Sample records for urea creatinine uric

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

    PubMed Central

    Musso, Carlos Guido; Álvarez Gregori, Joaquín; Jauregui, José Ricardo; Macías Núńez, Juan Florencio

    2012-01-01

    Renal physiology in the healthy oldest old has the following characteristics, in comparison with the renal physiology in the young: a reduced creatinine clearance, tubular pattern of creatinine back-filtration, preserved proximal tubule sodium reabsorption and uric acid secretion, reduced sodium reabsorption in the thick ascending loop of Henle, reduced free water clearance, increased urea excretion, presence of medulla hypotonicity, reduced urinary dilution and concentration capabilities, and finally a reduced collecting tubules response to furosemide which expresses a reduced potassium excretion in this segment due to a sort of aldosterone resistance. All physiological changes of the aged kidney are the same in both genders. PMID:24175249

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

    SciTech Connect

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

    1988-07-01

    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.

  3. Diagnosis of premature rupture of membranes by assessment of urea and creatinine in vaginal washing fluid

    PubMed Central

    Kariman, Nourossadat; Afrakhte, Maryam; Hedayati, Mehdi; Fallahian, Masoumeh; Alavi Majd, Hamid

    2013-01-01

    Background: Rupture of fetal membranes can occur at any gestational age. Premature rupture of membranes (PROM) means rupture of fetal membranes before the onset of labor. Objective: The purpose of this study was to evaluate and compare the reliability of the vaginal washing fluid urea and creatinine for the diagnosis of PROM and to determine cut-off values. Materials and Methods: A total of 179 pregnant women were recruited. All patients underwent different examinations. These included nitrazine paper test, fern test, amniotic fluid pooling, vaginal washing fluid urea and creatinine sampling. The one group consisted of 126 pregnant women between 14 and 41 weeks of gestation with the complaint of vaginal fluid leakage. Patients who had positive pooling, nitrazine paper test and fern test were considered as confirmed PROM group (group 1). On the other side, patients with pooling (-) and/or nitrazine paper test (-) and/or fern test (-) were taken as suspected unconfirmed PROM cases (group 2). The control group consisted of 53 pregnant women between 14 and 41 weeks of gestation without any complaint or complication. Weconducted one-way ANOVA test on the urea and creatinine measures and post-hoc comparison test. Cut-off value was determined by receiver operating characteristic (ROC) curve. Results: Vaginal fluid concentrations of urea and creatinine were significantly different between the three groups (p<0.001). The sensitivity, specificity, positive and negative predictive values and accuracy were all 100% in detecting premature rupture of membranes by evaluation of vaginal fluid creatinine concentration with a cut-off value of 0.45 mg/dl, respectively. Conclusion: This study demonstrates that of two markers investigated creatinine has the higher diagnostic power. PMID:24639733

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

    Microsoft Academic Search

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

    2006-01-01

    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

  5. Seasonal serum urea-creatinine ratios in wild and captive American badgers, Taxidea taxus.

    PubMed

    Harlow, H J; Nelson, R A

    1990-01-01

    1. Blood samples were taken from 22 American badgers in the field during different seasons and analysed for urea and creatinine. 2. The urea-creatinine ratio (U/C) of these animals did not decrease during the winter as previously reported for black bears. This suggests that the badger, unlike the bear, does not demonstrate a winter physiological state of protein conservation. 3. This may be the consequence of intermittent ingestion of protein by the badger during the winter, or due to biochemical mechanisms unique to the bear which allows for protein turnover and resynthesis. 4. Captive badgers fasted in the laboratory during the winter also did not exhibit lower U/C ratios and protein catabolism, compared to a summer fast, thereby supporting the latter hypothesis that badgers do not have an adjustment in protein catabolism during the winter season. PMID:1968814

  6. The effect of ginger extract on blood urea nitrogen and creatinine in mice.

    PubMed

    Mehrdad, Modaresi; Messripour, Manouchehr; Ghobadipour, Mozhgan

    2007-09-01

    The present study is going to determine whether ginger has positive or negative effects of kidney. A hydro alcoholic extract of ginger was administered intraperitoneally (IP) every 48 h to male mice for a period of 20 days. Control group received saline containing equal volume of ethanol. Blood Urea Nitrogen (BUN) and creatinine were measured spectrophotometrically. Administration of ginger extract markedly decreased the BUN concentrations in experimental mice in a non linear fashion with regard to the administrated dosages. However, little changes were observed in the levels of creatinine in these animals as compared with control group. It is concluded that ginger may have a beneficial effect for removal of urea from plasma and it may be considered as a therapeutic herb to manage renal function in patient with uremia. PMID:19090210

  7. Determination of creatinine, uric and ascorbic acid in bovine milk and orange juice by hydrophilic interaction HPLC.

    PubMed

    Zuo, Ruiting; Zhou, Si; Zuo, Yuegang; Deng, Yiwei

    2015-09-01

    Creatinine (Cr), uric (UA) and ascorbic acid (AA) are common constituents in human fluids. Their abnormal concentrations in human fluids are associated with various diseases. Thus, apart from the endogenous formation in human body, it is also important to examine their sources from food products. In this study, a rapid and accurate HILIC method was developed for simultaneous determination of Cr, UA and AA in bovine milk and orange juice. Milk samples were pretreated by protein precipitation, centrifugation and filtration, followed by HPLC separation and quantification using a Waters Spherisorb S5NH2 column. The developed method has been successfully applied to determine the concentration of UA, AA and Cr in milk and fruit juice samples. The milk samples tested were found to contain UA and creatinine in the concentration range of 24.1-86.0 and 5.07-11.2 ?g mL(-1), respectively. The orange juices contain AA over 212 ?g mL(-1). PMID:25842333

  8. [Effect of urea and uric acid on the hemolytic activity of Sendai virus].

    PubMed

    Tryba?a, E; Larski, Z; Wi?niewski, J

    1989-01-01

    It was found that haemolytic activity of Fushimi strain of Sendai virus multiplied in allantoic cavity of chicken embryos is independent on its haemagglutinating titer and also on allantoic fluid urea and uric acid content. It was shown in experiments with embryonated eggs that these two compounds have no also influence on haemolytic activity induction in Sendai virus. Moreover, the results of an experiment in which allantoic fluid was replaced by Eagle's liquid suggest that most probably the other components present in allantoic fluid do not also influence the appearance of haemolytic activity of this virus. PMID:2548047

  9. Artificial cell microcapsules containing genetically engineered E. coli DH5 cells for in-vitro lowering of plasma potassium, phosphate, magnesium, sodium, chloride, uric acid, cholesterol, and creatinine: a preliminary report.

    PubMed

    Prakash, S; Chang, T M

    1999-01-01

    Lowering of plasma Mg, P, Na, Cl, uric acid, cholesterol, and creatinine is required in renal failure and other diseases. In this preliminary report, we studied the ability of artificial cells microencapsulated genetically engineered E. coli DH5 cells in lower K, Mg, P, Na, Cl, uric acid, cholestrol, creatinine, and billirubin from plasma in-vitro. Result shows that this novel approach has the ability to significantly lower these metabolites from the plasma in-vitro. PMID:10595451

  10. Availability of Blood Urea Nitrogen/Creatinine Ratio in Gastrointestinal Bleeding with Melena in Children

    PubMed Central

    Kim, Kyu Seon; Kang, Chan Ho

    2015-01-01

    Purpose The aims of our study were to evaluate the blood urea nitrogen to creatinine ratio (BUN/Cr ratio) for distinguishing between an upper and lower gastrointestinal bleeding (GIB), and differentiating between the two most common causes of upper gastrointestinal bleeding (UGIB) presenting with melena in children. Methods Retrospective data of patients with GIB presenting with melena were analyzed. The data from 60 cases were reviewed including demographics, laboratory findings, diagnostic modalities and results, treatments, and transfusions. Results Among the 60 cases, UGIB and lower gastrointestinal bleeding (LGIB) were found in 35 cases (58.3%) and 14 cases (23.3%), respectively. The two common causes of UGIB were varices (37.1%), and peptic ulcer diseases (PUD) (31.4%). The BUN/Cr ratio of 30 or greater was higher in UGIB than LGIB (odds ratio [OR], 6.9; 95% confidence interval [95% CI], 1.3-37.2). In UGIB, the BUN/Cr ratio of the varices group was higher than that of the PUD group (p=0.015). The OR for the BUN/Cr ratio appeared as 1.2 per unit increase in the varices group than the PUD group (95% CI, 1.03-1.3). There was no difference between the PUD group and Meckel's diverticulum group. Conclusion The BUN/Cr ratio was not uneven in differentiating UGIB from LGIB of children with melena in our study. This suggests that BUN/Cr ratio should be interpreted carefully. PMID:25866731

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

    PubMed Central

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

    2014-01-01

    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. PMID:25568686

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

    PubMed Central

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

    2012-01-01

    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. PMID:25653747

  13. 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

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

    2015-01-01

    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

  14. Prediction of Creatinine Clearance from Serum Creatinine

    Microsoft Academic Search

    Donald W. Cockcroft; Henry Gault

    1976-01-01

    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

  15. Uric acid protection of nucleobases from ozone-induced degradation

    SciTech Connect

    Meadows, J.; Smith, R.C.

    1986-05-01

    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.

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

    PubMed Central

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

    2014-01-01

    Aim. Several studies indicated that hyperuricemia may link to the worsening of diabetic nephropathy (DN). Meanwhile, low protein diet (LPD) retards exacerbation of renal damage in chronic kidney disease. We then assessed whether LPD influences uric acid metabolism and benefits the progression of DN in streptozotocin- (STZ-) induced diabetic rats. Methods. STZ-induced and control rats were both fed with LPD (5%) and normal protein diet (18%), respectively, for 12 weeks. Vital signs, blood and urinary samples for UA metabolism were taken and analyzed every 3 weeks. Kidneys were removed at the end of the experiment. Results. Diabetic rats developed into constantly high levels of serum UA (SUA), creatinine (SCr) and 24?h amounts of urinary albumin excretion (UAE), creatintine (UCr), urea nitrogen (UUN), and uric acid (UUA). LPD significantly decreased SUA, UAE, and blood glucose, yet left SCr, UCr, and UUN unchanged. A stepwise regression showed that high UUA is an independent risk factor for DN. LPD remarkably ameliorated degrees of enlarged glomeruli, proliferated mesangial cells, and hyaline-degenerated tubular epithelial cells in diabetic rats. Expression of TNF-? in tubulointerstitium significantly decreased in LPD-fed diabetic rats. Conclusion. LPD inhibits endogenous uric acid synthesis and might accordingly attenuate renal damage in STZ-induced diabetic rats. PMID:24772444

  17. Creatinine clearance test

    MedlinePLUS

    ... creatinine clearance test is used to estimate glomerular filtration rate (GFR) . GFR is a measure of how ... Kasiske BL. Laboratory assessment of kidney disease: glomerular filtration rate, urinalysis, and proteinuria. In: Taal MW, Chertow ...

  18. Uric Acid Is Independently Associated with Diabetic Kidney Disease: A Cross-Sectional Study in a Chinese Population

    PubMed Central

    Jiang, Feng; Wang, Jie; Zhang, Rong; Sun, Xue; Wang, Tao; Wang, Shiyun; Bao, Yuqian; Hu, Cheng; Jia, Weiping

    2015-01-01

    Background Association between hyperuricaemia and chronic kidney disease has been studied widely, but the influence of uric acid on the kidneys remains controversial. We aimed to summarize the association between uric acid and diabetic kidney disease (DKD), and to evaluate the role of uric acid in DKD. Methods We enrolled 3,212 type 2 diabetic patients in a cross-sectional study. The patients’ basic characteristics (sex, age, BMI, duration of disease, and blood pressure) and chemical parameters (triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), microalbuminuria, creatinine, and uric acid) were recorded, and the association between uric acid and DKD was evaluated. Results In the 3,212 diabetic patients, the prevalence of diabetic kidney disease was higher in hyperuricaemic patients than in patients with normouricaemia (68.3% vs 41.5%). The prevalence of DKD increased with increasing uric acid (p <0.0001). Logistic analysis identified uric acid as an independent predictor of DKD (p <0.0001; adjusted OR (95%CI) = 1.005 (1.004–1.007), p <0.0001). Uric acid was positively correlated with albuminuria and creatinine levels (p<0.0001) but negatively correlated with eGFR (p<0.0001) after adjusting for confounding factors. Conclusions Hyperuricaemia is a risk factor for DKD. Serum uric acid levels within the high-normal range are independently associated with DKD. PMID:26029914

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

    PubMed Central

    2012-01-01

    Background The finding reported in a previous paper - alkalization of urine facilitates uric acid excretion - is contradictory to what one might expect to occur: because food materials for the alkalization of urine contain fewer purine bodies than those for acidification, less uric acid in alkaline urine should have been excreted than in acid urine. To make clear what component of uric acid excretion mechanisms is responsible for this unexpected finding, we simultaneously collected data for the concentration of both creatinine and uric acid in serum as well as in urine, in order to calculate both uric acid and creatinine clearances. Methods Within the framework of the Japanese government’s health promotion program, we made recipes which consisted of protein-rich and less vegetable-fruit food materials for H?+?-load (acidic diet) and others composed of less protein and more vegetable-fruit rich food materials (alkaline diet). This is a crossover study within some limitations. Healthy female students, who had no medical problems at the regular physical examination provided by the university, were enrolled in this consecutive 5-day study for each test. From whole-day collected urine, total volume, pH, organic acid, creatinine, uric acid, titratable acid and all cations (Na+,K+,Ca2+,Mg2+,NH4+) and anions (Cl?,SO42?,PO4?) necessary for the estimation of acid–base balance were measured. In the early morning before breakfast of the 1st, 3rd and 5th experimental day, we sampled 5?mL of blood to estimate the creatinine and uric acid concentration in serum. Results and discussion Urine pH reached a steady state 3?days after switching from ordinary daily diets to specified regimens. The amount of acid generated ([SO42?]?+?organic acid???gut alkali)was linearly related with the excretion of acid (titratable acid?+?[NH4+]???[HCO3?]), indicating that H?+?in urine is generated by the metabolic degradation of food materials. Uric acid and excreted urine pH retained a linear relationship, as reported previously. Among the five factors which are associated with calculating clearances for both uric acid and creatinine, we identified a conspicuous difference between acidic and alkaline diets in the uric acid concentration in serum as well as in urine; uric acid in the serum was higher in the acidic group than in the alkaline group, while uric acid in the urine in the acidic group was lower than that in the alkaline group. These changes of uric acid in acidic urine and in serum were reflected in the reduction of its clearance. From these observations, it is considered that uric acid may be reabsorbed more actively in acidic urine than in alkaline urine. Conclusion We conclude that alkalization of urine by eating nutritionally well-designed alkaline -prone food is effective for removing uric acid from the body. PMID:22676161

  20. Stamping SERS for creatinine sensing

    NASA Astrophysics Data System (ADS)

    Li, Ming; Du, Yong; Zhao, Fusheng; Zeng, Jianbo; Santos, Greggy M.; Mohan, Chandra; Shih, Wei-Chuan

    2015-03-01

    Urine can be obtained easily, readily and non-invasively. The analysis of urine can provide metabolic information of the body and the condition of renal function. Creatinine is one of the major components of human urine associated with muscle metabolism. Since the content of creatinine excreted into urine is relatively constant, it is used as an internal standard to normalize water variations. Moreover, the detection of creatinine concentration in urine is important for the renal clearance test, which can monitor the filtration function of kidney and health status. In more details, kidney failure can be imminent when the creatinine concentration in urine is high. A simple device and protocol for creatinine sensing in urine samples can be valuable for point-of-care applications. We reported quantitative analysis of creatinine in urine samples by using stamping surface enhanced Raman scattering (S-SERS) technique with nanoporous gold disk (NPGD) based SERS substrate. S-SERS technique enables label-free and multiplexed molecular sensing under dry condition, while NPGD provides a robust, controllable, and high-sensitivity SERS substrate. The performance of S-SERS with NGPDs is evaluated by the detection and quantification of pure creatinine and creatinine in artificial urine within physiologically relevant concentration ranges.

  1. Urine Albumin and Albumin/ Creatinine Ratio

    MedlinePLUS

    ... limited. Search Help? Urine Albumin and Albumin/Creatinine Ratio Share this page: Was this page helpful? Also ... UACR Formal name: Urine Albumin; Albumin-to-Creatinine Ratio Related tests: Albumin ; Creatinine ; Glucose ; A1c ; Urine Protein ; ...

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

    SciTech Connect

    Meadows, J.R.

    1986-01-01

    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.

  3. [Uric acid and multiple sclerosis].

    PubMed

    Mattle, H P; Lienert, C; Greeve, I

    2004-09-01

    Multiple Sclerosis (MS) is a chronic inflammatory disease of the central nervous system. Its etiology is not known, but it is well established that auto-reactive T-cells and monocytes play an important pathogenetic role. Experimental allergic encephalomyelitis (EAE) of mice serves as disease model for MS. In both EAE and MS inflammatory cells produce nitric oxide and its oxidizing congeners such as peroxynitrite. Peroxynitrite and other reactive nitrogen oxide species exert a toxic effect on neurons, axons and glia cells and enhance apoptosis. In addition, they increase the blood-CNS-barrier permeability and can therefore promote invasion of inflammatory cells into the CNS. On the other hand, uric acid, a peroxynitrite scavenger inhibits blood-CNS-barrier permeability changes, CNS inflammation and tissue damage in EAE. Epidemiological studies have shown that MS and gout are almost mutually exclusive diseases. Uric acid levels in MS patients are lower than in controls and in patients with active disease lower than in MS patients in remission. Inosine, a uric acid precursor, can be used to raise uric acid levels in serum and may provide some benefit in MS patients. A small study of ten patients with progressive MS has demonstrated some improved function in three of them and no sign of progression or relapse in the other. However, this study does not justify a recommendation for use of inosine in MS patients yet. At present, uric acid can solely be regarded as a marker of disease activity in MS. In addition, the current knowledge of uric acid and MS supports hypotheses which predict a positive effect of radical scavengers in MS. PMID:15493114

  4. Prognostic significance of serum uric acid in women with gestational hypertension.

    PubMed

    Bellomo, Gianni; Venanzi, Sandro; Saronio, Paolo; Verdura, Claudio; Narducci, Pier Luca

    2011-10-01

    Aim of our study was to ascertain, prospectively, whether serum uric acid is a suitable predictor of preeclampsia and/or the delivery of small-for-gestational-age infants in women with gestational hypertension. We screened 206 primiparas, with a singleton pregnancy, referred for recent onset of hypertension. At presentation, we measured serum uric acid, creatinine, blood glucose, hemoglobin and platelet level, and 24-hour proteinuria, as well as office and 24-hour blood pressures. We followed the women until 1 month after delivery and recorded pregnancy outcome. After logistic regression analysis, uric acid resulted a significant predictor of preeclampsia, with an unadjusted odds ratio of 9.1 (95% CI: 4.8 to 17.4; P<0.001); after adjustment for age, gestation week, hemoglobin and platelet levels, serum creatinine, office and 24-hour average systolic and diastolic blood pressures, it was 7.1 (95% CI: 3.2 to 15.7; P<0.001). Regarding the association between maternal serum uric acid and the chance of giving birth to a small-for-gestational-age infant, the unadjusted odds ratio was 1.7 (95% CI: 1.4 to 2.2; P<0.001), and it was 1.6 (95% CI: 1.1 to 2.4; P=0.02) after adjustment. Receiver operating characteristic analysis showed that serum uric acid, at a 309-?mol/L cutoff, predicted the development of preeclampsia (area under the curve: 0.955), with 87.7% sensitivity and 93.3% specificity, and the delivery of small-for-gestational-age infants (area under the curve: 0.784) with 83.7% sensitivity and 71.7% specificity. In conclusion, the results of our study show that serum uric acid is a reliable predictor of preeclampsia in women referred for gestational hypertension. PMID:21876075

  5. Correlation of serum uric acid with bone mineral density and fragility fracture in patients with primary osteoporosis: a single-center retrospective study of 253 cases

    PubMed Central

    Chen, Lin; Peng, Yongde; Fang, Fang; Chen, Jinyu; Pan, Ling; You, Li

    2015-01-01

    Objective: This study aimed to investigate the correlation of serum uric acid with bone mineral density (BMD) and fragility fracture in primary osteoporosis (PO) patients. Methods: A retrospective analysis of biochemical parameters including bone turnover markers and bone density was done in patients (n=253) received initial treatment for PO from January 2011 to May 2012 at the Shanghai First People’s Hospital. Results: Pearson correlation analysis and multiple regression analysis showed that serum uric acid positively correlated with the lumbar spine BMD (P<0.05); serum uric acid negatively correlated with urine calcium/creatinine ratio, but positively correlated with blood 25-hydroxyvitamin D (25 [OH] D) (P<0.05); the serum uric acid in postmenopausal women with the history of fragility fracture was significantly lower than that in women without the this disease history. Conclusion: Serum uric acid may be a protective factor of bone metabolism in primary osteoporosis patients.

  6. Does the adequacy parameter Kt/V(urea) reflect uremic toxin concentrations in hemodialysis patients?

    PubMed

    Eloot, Sunny; Van Biesen, Wim; Glorieux, Griet; Neirynck, Nathalie; Dhondt, Annemieke; Vanholder, Raymond

    2013-01-01

    Hemodialysis aims at removing uremic toxins thus decreasing their concentrations. The present study investigated whether Kt/V(urea), used as marker of dialysis adequacy, is correlated with these concentrations. Predialysis blood samples were taken before a midweek session in 71 chronic HD patients. Samples were analyzed by colorimetry, HPLC, or ELISA for a broad range of uremic solutes. Solute concentrations were divided into four groups according to quartiles of Kt/V(urea), and also of different other parameters with potential impact, such as age, body weight (BW), Protein equivalent of Nitrogen Appearance (PNA), Residual Renal Function (RRF), and dialysis vintage. Dichotomic concentration comparisons were performed for gender and Diabetes Mellitus (DM). Analysis of Variance in quartiles of Kt/V(urea) did not show significant differences for any of the solute concentrations. For PNA, however, concentrations showed significant differences for urea (P<0.001), uric acid (UA), p-cresylsulfate (PCS), and free PCS (all P<0.01), and for creatinine (Crea) and hippuric acid (HA) (both P<0.05). For RRF, concentrations varied for ??-microglobulin (P<0.001), HA, free HA, free indoxyl sulfate, and free indole acetic acid (all P<0.01), and for p-cresylglucuronide (PCG), 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF), free PCS, and free PCG (all P<0.05). Gender and body weight only showed differences for Crea and UA, while age, vintage, and diabetes mellitus only showed differences for one solute concentration (UA, UA, and free PCS, respectively). Multifactor analyses indicated a predominant association of concentration with protein intake and residual renal function. In conclusion, predialysis concentrations of uremic toxins seem to be dependent on protein equivalent of nitrogen appearance and residual renal function, and not on dialysis adequacy as assessed by Kt/V(urea). Efforts to control intestinal load of uremic toxin precursors by dietary or other interventions, and preserving RRF seem important approaches to decrease uremic solute concentration and by extension their toxicity. PMID:24236005

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

    PubMed Central

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

    1964-01-01

    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

  8. Evaluation of Dietary Nitrogen Utilization in Dairy Cows Based on Urea Concentrations in Blood, Urine and Milk, and on Urinary Concentration of Purine Derivatives

    Microsoft Academic Search

    Horacio Leandro Gonda; Jan Erik Lindberg

    1994-01-01

    The effects of level and degradability of dietary protein on urea in blood, urine and milk, and on the urinary purine derivatives and creatinine in dairy cows, were studied. Diurnal variation in urinary concentration of urea, allantoin and creatinine was also studied. A total of 24 multiparous lactating dairy cows were selected from a production experiment and divided into two

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

    Microsoft Academic Search

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

    1997-01-01

    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

  10. Online measurement of urea concentration in spent dialysate during hemodialysis

    NASA Astrophysics Data System (ADS)

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

    2002-05-01

    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.

  11. Raised blood urea in the elderly: a clinical and pathological study.

    PubMed Central

    Bowker, L. K.; Briggs, R. S.; Gallagher, P. J.; Robertson, D. R.

    1992-01-01

    We have attempted to define a normal range for blood urea and creatinine for elderly inpatients and to determine the relative importance of pre-renal, renal and post-renal pathology in those with renal impairment. A total of 118 admissions to an acute geriatric unit and 67 separate post mortems in patients over 67 years of age were studied prospectively. Up to 123 items of data were coded and analysed including blood urea and creatinine, clinical or pathological changes associated with renal disease, clinical outcome and post mortem findings. We determined our own 'normal' hospital ranges for urea (1.4-13.2 mmol/l) and creatinine (48-141 mumol/l) from plasma values in 76 patients with no evidence of renal impairment, either on admission or in the past. Using these values 41% of post mortem cases and 25% of clinical admissions had a raised blood urea. Pre-renal conditions such as cardiac failure, dehydration and gastrointestinal haemorrhage, either alone or in combination, were present in 56% of these patients. Urea and creatinine values were substantially higher in patients who died in hospital as opposed to those who were discharged or transferred. Creatinine values were greater in those with intrinsic renal disease or post-renal obstruction as compared to patients with pre-renal causes of renal impairment. Patients with histological evidence of extensive glomerulosclerosis or nephrosclerosis had higher urea and creatinine levels than those with only minor ageing changes. PMID:1589374

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    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.

  13. Uric Acid Promotes Tumor Immune Rejection

    Microsoft Academic Search

    De-En Hu; Alistair M. Moore; Lindy L. Thomsen; Kevin M. Brindle

    2004-01-01

    Uric acid released from dying cells has been shown recently to act as a danger signal for the immune system, stimulating dendritic cell matura- tion and enhancing T-cell responses to foreign antigens. Stimulation of dendritic cell maturation by uric acid has been proposed as a mechanism by which the immune system could generate responses against tumors. We show here that

  14. Blood creatinine level in postmortem cases.

    PubMed

    Nishida, Atsushi; Funaki, Hironao; Kobayashi, Masaki; Tanaka, Yuka; Akasaka, Yoshihisa; Kubo, Toshikazu; Ikegaya, Hiroshi

    2015-05-01

    Blood chemical analysis for the diagnosis of diseases in forensic cases should be conducted in the same way as for clinical cases. However, it is sometimes difficult to obtain serum samples in forensic cases because of postmortem changes such as hemolysis and putrefaction. This study aimed to evaluate renal function in postmortem cases by blood creatinine analysis. The blood creatinine level was measured by high performance liquid chromatography (HPLC) using whole blood samples taken from 77 postmortem cases, and the relationships between blood creatinine level, postmortem interval, and cause of death were examined. The median blood creatinine level was found to be 1.15mg/dL, with no significant differences between blood samples taken from different parts of the body. The blood creatinine level was stable for 3days after death and gradually increased after that period, in line with a previous study using enzymatic analysis that found the serum creatinine level was stable in the early postmortem period. The blood creatinine level was high in the cases of blunt injury, intoxication, and in deaths caused by fire. This was considered to reflect acute renal dysfunction. However, the postmortem blood creatinine level remained higher than the clinical normal value despite omitting cases with renal dysfunction from the analysis. Therefore, we next investigated the change in postmortem creatinine levels in mice and found that the blood creatinine level increased with the emergence of rigor mortis. Our findings indicate that HPLC is useful in the postmortem evaluation of renal function even in the cases where serum cannot be obtained. However, the presence of rigor mortis should be considered in the evaluation of blood creatinine values. PMID:25934372

  15. UREA INFRASTRUCTURE FOR UREA SCR NOX REDUCTION

    SciTech Connect

    Bunting, Bruce G.

    2000-08-20

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

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

    PubMed Central

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

    2014-01-01

    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

  17. Plasma Creatinine Clearance in the Dog

    ERIC Educational Resources Information Center

    Frazier, Loy W.

    1977-01-01

    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)

  18. Uric Acid, Hyperuricemia and Vascular Diseases

    PubMed Central

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

    2011-01-01

    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

  19. Reagent- and separation-free measurements of urine creatinine concentration using stamping surface enhanced Raman scattering (S-SERS)

    PubMed Central

    Li, Ming; Du, Yong; Zhao, Fusheng; Zeng, Jianbo; Mohan, Chandra; Shih, Wei-Chuan

    2015-01-01

    We report a novel reagent- and separation-free method for urine creatinine concentration measurement using stamping surface enhanced Raman scattering (S-SERS) technique with nanoporous gold disk (NPGD) plasmonic substrates, a label-free, multiplexed molecular sensing and imaging technique recently developed by us. The performance of this new technology is evaluated by the detection and quantification of creatinine spiked in three different liquids: creatinine in water, mixture of creatinine and urea in water, and creatinine in artificial urine within physiologically relevant concentration ranges. Moreover, the potential application of our method is demonstrated by creatinine concentration measurements in urine samples collected from a mouse model of nephritis. The limit of detection of creatinine was 13.2 nM (0.15 µg/dl) and 0.68 mg/dl in water and urine, respectively. Our method would provide an alternative tool for rapid, cost-effective, and reliable urine analysis for non-invasive diagnosis and monitoring of renal function. PMID:25798309

  20. Uric Acid May Limit Stroke Disability in Women

    MedlinePLUS

    Uric Acid May Limit Stroke Disability In Women But study found no benefit for men, and plan further research ... recovering without disabilities if they're given uric acid along with standard "clot-busting" medication, a new ...

  1. [Creatinine clearance as the foundation for clinical determination of kidney function in swine].

    PubMed

    Waldmann, K H; Wendt, M; Bickhardt, K

    1991-08-01

    Comparative examinations of renal function using inulin- and endogenous creatinine-clearance tests in 5 pigs showed nearly identical values of glomerular filtration rate (GFR). Based on this relation 79 healthy pigs, weighting 2 kg to 230 kg were investigated using the creatinine-clearance test for determination of normal values of GFR and urine flow rate (Vu) as well as renal excretion (E), renal clearance (Clr) and fractional excretion (FE) of urea, sodium, potassium, calcium, phosphorus, glucose and lactate. The renal excretion of creatinine (E-Creat) was closely correlated with the body weight. Therefore it is possible to use the body weight for estimation of E-Creat and to calculate GFR and Vu using plasma and urine concentrations of creatinine independent of a timed volumetric urine collection. Subsequently E, Clr and FE of electrolytes or other endogenous substances can be evaluated. Finally the practicability of this procedure for detection of disturbed glomerular filtration or tubular reabsorption was demonstrated in piglets suffering from colidiarrhoea and/or transmissible gastroenteritis. PMID:1948984

  2. Original article Evaluation of urinary creatinine excretion

    E-print Network

    Boyer, Edmond

    in the urine. Dinning et al. [8] concluded that daily excretion of creatinine is not affected by protein intake Agricultural Research Centre-Ghent, Department Animal Nutrition and Husbandry, Scheldeweg 68, 9090 Melle fasted live weight (fLW) range (308­710 kg), kg water and protein in the empty body were quite accurately

  3. Anaerobic Degradation of Uric Acid by Gut Bacteria of Termites †

    PubMed Central

    Potrikus, C. J.; Breznak, John A.

    1980-01-01

    A study was done of anaerobic degradation of uric acid (UA) by representative strains of uricolytic bacteria isolated from guts of Reticulitermes flavipes termites. Streptococcus strain UAD-1 degraded UA incompletely, secreting a fluorescent compound into the medium, unless formate (or a formicogenic compound) was present as a cosubstrate. Formate functioned as a reductant, and its oxidation to CO2 by formate dehydrogenase provided 2H+ + 2e? needed to drive uricolysis to completion. Uricolysis by Streptococcus UAD-1 thus corresponded to the following equation: 1UA + 1formate ? 4CO2 + 1acetate + 4NH3. Urea did not appear to be an intermediate in CO2 and NH3 formation during uricolysis by strain UAD-1. Formate dehydrogenase and uricolytic activities of strain UAD-1 were inducible by growth of cells on UA. Bacteroides termitidis strain UAD-50 degraded UA as follows: 1UA ? 3.5 CO2 + 0.75acetate + 4NH3. Exogenous formate was neither required for nor stimulatory to uricolysis by strain UAD-50. Studies of UA catabolism by Citrobacter strains were limited, because only small amounts of UA were metabolized by cells in liquid medium. Uricolytic activity of such bacteria in situ could be important to the carbon, nitrogen, and energy economy of R. flavipes. PMID:16345588

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

    MedlinePLUS

    ... What to Know Urine Test: Microalbumin-to-Creatinine Ratio KidsHealth > Parents > Doctors & Hospitals > Medical Tests & Exams > Urine Test: Microalbumin-to-Creatinine Ratio Print A A A Text Size What's in ...

  5. Limitations of creatinine as a filtration marker in glomerulopathic patients

    Microsoft Academic Search

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

    1985-01-01

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

  6. Denaturing Urea Polyacrylamide Gel Electrophoresis (Urea PAGE)

    PubMed Central

    Summer, Heike; Grämer, René; Dröge, Peter

    2009-01-01

    Urea PAGE or denaturing urea polyacrylamide gel electrophoresis employs 6-8 M urea, which denatures secondary DNA or RNA structures and is used for their separation in a polyacrylamide gel matrix based on the molecular weight. Fragments between 2 to 500 bases, with length differences as small as a single nucleotide, can be separated using this method1. The migration of the sample is dependent on the chosen acrylamide concentration. A higher percentage of polyacrylamide resolves lower molecular weight fragments. The combination of urea and temperatures of 45-55 °C during the gel run allows for the separation of unstructured DNA or RNA molecules. In general this method is required to analyze or purify single stranded DNA or RNA fragments, such as synthesized or labeled oligonucleotides or products from enzymatic cleavage reactions. In this video article we show how to prepare and run the denaturing urea polyacrylamide gels. Technical tips are included, in addition to the original protocol 1,2. PMID:19865070

  7. Luteolin prevents uric acid-induced pancreatic ?-cell dysfunction.

    PubMed

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

    2014-07-01

    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

  8. Urea Cycle Disease Overview

    MedlinePLUS

    ... be delayed for months or years. Early in life, infants with urea cycle disorders develop toxic levels of ammonia build-up ... for the presence of a UCD. Amino acid analysis can be used to diagnose a specific urea cycle disorder. The amino acid arginine may be reduced ...

  9. Allopurinol, uric acid, and oxidative stress in cardiorenal disease

    Microsoft Academic Search

    Markus Riegersperger; Adrian Covic; David Goldsmith

    2011-01-01

    In humans, the hepatic end product of purine metabolism is uric acid. Serum uric acid levels physiologically and gradually\\u000a rise during human lifetime. Hyperuricemia also arises from excess dietary purine or ethanol intake, decreased renal excretion\\u000a of uric acid, tumor lysis in lymphoma, leukemia or solid tumors, and sometimes pharmacotherapy. The definition of hyperuricemia\\u000a is currently arbitrary. Hyperuricemia is associated

  10. Association between serum uric acid and motor subtypes of Parkinson's disease.

    PubMed

    Lolekha, Praween; Wongwan, Piyanat; Kulkantrakorn, Kongkiat

    2015-08-01

    The aim of this study was to evaluate serum uric acid (UA) levels and serum uric acid/creatinine ratios (UA/Cr) in patients with non-tremor dominant (NTD) Parkinson's disease (PD) compared to tremor dominant (TD) PD and healthy controls (HC). UA is believed to have a protective effect on the central nervous system against oxidative damage and neuronal cell death which could impact on progression and motor subtypes of PD. Serum UA levels and UA/Cr were determined in 100 PD patients and 100 age and sex matched HC. Subtypes of PD were classified into TD and NTD. Patients with PD showed statistically significantly lower serum UA (p=0.007) and serum UA/Cr ratios (p<0.001) than HC. Patients with NTD PD had statistically significantly lower serum UA (p<0.001) and serum UA/Cr (p=0.001) than in patients with TD PD. Patients with mild PD severity also had significantly higher serum UA (p=0.015) and serum UA/Cr (p=0.004) than patients with moderate to severe disease. Our study suggests that UA has a pathogenic role in the clinical subtype of PD. Serum UA levels together with serum UA/Cr are potentially useful biomarkers to indicate risk, severity and motor subtype of PD. PMID:26055955

  11. [Renal regulation of the excretion of urea in fasting camels].

    PubMed

    Leng, L; Bod'a, K; Tasenov, K T; Karinbaev, R S; Makasev, E K; Rachimberdiev, S A; Tlegenov, D K; Jurgalieva, L A

    1984-09-01

    Experiments were performed with young two-humped camels exposed to 36-hour starvation with free access to water. The renal functions were measured by the standard clearance method. In spite of the administration of 20 micrograms DDAVP, a higher urine flow rate was recorded in the camels subjected to control measurements (feed intake) than in the fasting period (1.45 +/- 0.06 vs. 0.96 +/- 0.06 ml . min-1, P less than less than 0.001). On the second day of fasting the camels had a significantly reduced glomerular filtration rate (GFR 317.5 +/- 23.2 vs. 170.2 +/- 17.4 ml . min-1, P less than 0.001), urea output (700.5 +/- 62.9 vs. 352.2 +/- 64.7 mumol . min-1, P less than 0.005), and fractional excretion of urea (26.9 +/- 2.8 vs. 17.9 +/- 1.7%, P less than 0.01), whereas their tubular resorption. of urea (Reab urea/GFR) increased (6.28 +/- 0.61 vs. 9.12 +/- 0.82 mumol . ml-1, P less than 0.02). No significant difference was found in the concentration of urea in plasma in the fed camels and in fasting camels (8.55 +/- 0.64 vs. 11.18 +/- 1.09 mmol . l-1, N. S.). The creatinine inulin clearance ratio (C creat/Cin) was 0.92 +/- 0.07 when the animals were fed and 1.17 +/- 0.05 when the animals starved (P less than 0.001); this suggests that the clearance of endogenous creatinine is not suitable for GFR measurement in camels under different conditions of nutrition. The kidneys of camels regulate the excretion of urea during short-time fasting mainly through the reduction of glomerular filtration rate and just partly through an increased tubular resorption. PMID:6438869

  12. Role of insulin resistance in uric acid nephrolithiasis

    PubMed Central

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

    2014-01-01

    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

  13. Role of insulin resistance in uric acid nephrolithiasis.

    PubMed

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

    2014-11-01

    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

  14. glucose (GLU), urea (UR), creatinine (CR) and cholesterol (CHOL) and the activity of

    E-print Network

    Paris-Sud XI, Université de

    cows. The effect of the BL allele on productivity was estimated from the statistical analysis of milk pro- ductivity of 140 cow - half sisters (71 wild type and 69 carriers of the BL allele). All were/TL cows pro- duced 734.56 kg of milk and 23.79 kg of #12;milk protein more than their TL/TL half sis- ters

  15. Elevated plasma creatinine due to creatine ethyl ester use.

    PubMed

    Velema, M S; de Ronde, W

    2011-02-01

    Creatine is a nutritional supplement widely used in sport, physical fitness training and bodybuilding. It is claimed to enhance performance. We describe a case in which serum creatinine is elevated due to the use of creatine ethyl esther. One week after withdrawal, the plasma creatinine had normalised. There are two types of creatine products available: creatine ethyl esther (CEE) and creatine monohydrate (CM). Plasma creatinine is not elevated in all creatine-using subjects. CEE , but not CM, is converted into creatinine in the gastrointestinal tract. As a result the use of CEE may be associated with elevated plasma creatinine levels. Since plasma creatinine is a widely used marker for renal function, the use of CEE may lead to a false assumption of renal failure. PMID:21411845

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

    PubMed Central

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

    2012-01-01

    Background Patients with chronic kidney disease (CKD) need regular monitoring, usually by blood urea and creatinine measurements, needing venepuncture, frequent attendances and a healthcare professional, with significant inconvenience. Noninvasive monitoring will potentially simplify and improve monitoring. We tested the potential of transdermal reverse iontophoresis of urea in patients with CKD and healthy controls. Methods Using a MIC 2® Iontophoresis Controller, reverse iontophoresis was applied on the forearm of five healthy subjects (controls) and 18 patients with CKD for 3–5 h. Urea extracted at the cathode was measured and compared with plasma urea. Results Reverse iontophoresis at 250 ?A was entirely safe for the duration. Cathodal buffer urea linearly correlated with plasma urea after 2 h (r = 0·82, P < 0·0001), to 3·5 h current application (r = 0·89, P = 0·007). The linear equations y = 0·24x + 1 and y = 0·21x + 4·63 predicted plasma urea (y) from cathodal urea after 2 and 3 h, respectively. Cathodal urea concentration in controls was significantly lower than in patients with CKD after a minimum current application of 2 h (P < 0·0001), with the separation between the two groups becoming more apparent with longer application (P = 0·003). A cathodal urea cut-off of 30 ?M gave a sensitivity of 83·3% and positive predictive value of 87% CKD. During haemodialysis, the fall in cathodal urea was able to track that of blood urea. Conclusion Reverse iontophoresis is safe, can potentially discriminate patients with CKD and healthy subjects and is able to track blood urea changes on dialysis. Further development of the technology for routine use can lead to an exciting opportunity for its use in diagnostics and monitoring. PMID:22409780

  17. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...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)...

  18. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...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....

  19. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...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....

  20. Linking uric acid metabolism to diabetic complications

    PubMed Central

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

    2014-01-01

    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

  1. Linking uric acid metabolism to diabetic complications.

    PubMed

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

    2014-12-15

    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

  2. Detection of Interstellar Urea

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  3. Effects of moderate-dose versus high-dose trimethoprim on serum creatinine and creatinine clearance and adverse reactions.

    PubMed Central

    Naderer, O; Nafziger, A N; Bertino, J S

    1997-01-01

    The effects of a 10-day course of moderate-dose (10 mg/kg/day) or high-dose (20 mg/kg/day) trimethoprim therapy on serum creatinine, measured creatinine clearance, urinary creatinine excretion, and serum folate were studied in 20 healthy volunteers. Serum creatinine concentrations increased significantly during trimethoprim therapy, began to decrease near day 10, and returned to baseline during the washout phase at both dosage levels. At the same time, measured creatinine clearance and urine creatinine changed in the opposite direction. No clinical or statistical differences were noted between changes in the moderate- versus the high-dose phases. Serum folate concentration decreases during high-dose trimethoprim therapy were statistically significant. Adverse drug reactions in the two groups were statistically different during the first study period, with the high-dose group having a 75% incidence rate and the moderate-dose group having an 11% incidence rate (P < 0.02). Serum creatinine, measured creatinine clearance, and urinary creatinine excretion demonstrated statistically, but not clinically, significant changes during trimethoprim therapy. In addition, high-dose trimethoprim caused significantly more adverse drug reactions than moderate-dose trimethoprim in normal volunteers. PMID:9371351

  4. The effect of co-trimoxazole on serum creatinine.

    PubMed Central

    Dijkmans, B A; van Hooff, J P; de Wolff, F A; Mattie, H

    1981-01-01

    1 Co-trimoxazole induces a highly significant and reversible elevation of the serum creatinine level. 2 In renal-allograft patients the degree of this elevation is significantly correlated with the concentration of serum creatinine before administration of co-trimoxazole and with the concentration of non-protein-bound trimethoprim. PMID:6977366

  5. Chemiresistor urea sensor

    DOEpatents

    Glass, Robert S. (Livermore, CA)

    1997-01-01

    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.

  6. Molecular evolution of urea amidolyase and urea carboxylase in fungi

    PubMed Central

    2011-01-01

    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

  7. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...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....

  8. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...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....

  9. CalorimetricEnzymicMeasurement of UricAcidin Serum

    Microsoft Academic Search

    Nadja N. Rehak; Gail Janes

    Uric acid in serum was determined calorimetrically with a batch type microcalorimeter, by measuring the heat evolved during a coupled uricase\\/catalase enzymic re.- action in tris(hydroxymethyl)aminomethane HCI buffer (pH 9.0 at 30 #{176}C). Heat evolutionandconcentrationare linearly related throughthe physiologicalrangeof serum uric acid concentrationsand the method is free of interferences of the sort encountered with spectrophotometric methods. Precisionandaccuracy are good(CV, 2%)

  10. Focusing on the clinical impact of standardization of creatinine measurements: a report by the EFCC Working Group on Creatinine Standardization.

    PubMed

    Delanghe, Joris R; Cobbaert, Christa; Harmoinen, Aimo; Jansen, Rob; Laitinen, Päivi; Panteghini, Mauro

    2011-06-01

    The recent campaign for standardization of creatinine measurements has been promoted to allow the widespread use of formulas for estimating the glomerular filtration rate (GFR). However, studies on trueness verification and measurement interferences still show disappointing interassay variation of serum creatinine results. Creatinine recalibration has major clinical consequences. In particular, in pediatrics where reference ranges for serum and plasma creatinine are low, calculation of the GFR is problematic when based on alkaline picrate methods because of method non-specificity and the lack of appropriate GFR estimating formulas. Therefore, enzymatic creatinine assays are preferred. In the near future, cystatin C might offer an interesting alternative for GFR estimation. For the calculation of drug doses, the Modification of Diet in Renal Disease study formula generally offers reliable data. However, attention has to be paid to the elderly. Also, the calculation of the Model for End-Stage Liver Disease score, which is used to prioritize patients for liver transplantation, may significantly be influenced by recalibration of creatinine assays. Creatinine restandardization may also affect the current guidelines for referral of chronic kidney disease patients to nephrologists. PMID:21428858

  11. Improved GFR estimation by combined creatinine and cystatin C measurements

    Microsoft Academic Search

    Y-C Ma; L Zuo; J-H Chen; Q Luo; X-Q Yu; Y Li; J-S Xu; S-M Huang; L-N Wang; W Huang; M Wang; G-B Xu; H-Y Wang

    2007-01-01

    Plasma creatinine may not reflect glomerular filtration rate (GFR) especially in the early stages of chronic kidney disease (CKD). Plasma cystatin C (cysC), however, has the potential to more accurately determine early GFR reduction. We sought to improve the creatinine-based GFR estimation by including cysC measurements. We derived a reference GFR from standard dual plasma sampling 99mTc-DTPA clearance in a

  12. Chemiresistor urea sensor

    DOEpatents

    Glass, R.S.

    1997-12-16

    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.

  13. Renal Transport of Uric Acid: Evolving Concepts and Uncertainties

    PubMed Central

    Bobulescu, Ion Alexandru; Moe, Orson W.

    2013-01-01

    In addition to its role as a metabolic waste product, uric acid has been proposed to be an important molecule with multiple functions in human physiology and pathophysiology and may be linked to human diseases beyond nephrolithiasis and gout. Uric acid homeostasis is determined by the balance between production, intestinal secretion, and renal excretion. The kidney is an important regulator of circulating uric acid levels, by reabsorbing around 90% of filtered urate, while being responsible for 60–70% of total body uric acid excretion. Defective renal handling of urate is a frequent pathophysiologic factor underpinning hyperuricemia and gout. In spite of tremendous advances over the past decade, the molecular mechanisms of renal urate transport are still incompletely understood. Many transport proteins are candidate participants in urate handling, with URAT1 and GLUT9 being the best characterized to date. Understanding these transporters is increasingly important for the practicing clinician as new research unveils their physiology, importance in drug action, and genetic association with uric acid levels in human populations. The future may see the introduction of new drugs that specifically act on individual renal urate transporters for the treatment of hyperuricemia and gout. PMID:23089270

  14. Dietary protein-induced increases in urinary calcium are accompanied by similar increases in urinary nitrogen and urinary urea: a controlled clinical trial.

    PubMed

    Bihuniak, Jessica D; Simpson, Christine A; Sullivan, Rebecca R; Caseria, Donna M; Kerstetter, Jane E; Insogna, Karl L

    2013-03-01

    To determine the usefulness of urinary urea as an index of dietary protein intake, 10 postmenopausal women were enrolled in and completed a randomized, double-blind, cross-over feeding trial from September 2008 to May 2010 that compared 10 days of a 45-g whey supplement with 10 days of a 45-g maltodextrin control. Urinary nitrogen, urinary calcium, urinary urea, and bone turnover markers were measured at days 0, 7, and 10. Paired sample t tests, Pearson's correlation statistic, and simple linear regression were used to assess differences between treatments and associations among urinary metabolites. Urinary nitrogen/urinary creatinine rose from 12.3±1.7 g/g (99.6±13.8 mmol/mmol) to 16.8±2.2 g/g (135.5±17.8 mmol/mmol) with whey supplementation, but did not change with maltodextrin. Whey supplementation caused urinary calcium to rise by 4.76±1.84 mg (1.19±0.46 mmol) without a change in bone turnover markers. Because our goal was to estimate protein intake from urinary nitrogen/urinary creatinine, we used our data to develop the following equation: protein intake (g/day)=71.221+1.719×(urinary nitrogen, g)/creatinine, g) (R=0.46, R(2)=0.21). As a more rapid and less costly alternative to urinary nitrogen/urinary creatinine, we next determined whether urinary urea could predict protein intake and found that protein intake (g/day)=63.844+1.11×(urinary urea, g/creatinine, g) (R=0.58, R(2)=0.34). These data indicate that urinary urea/urinary creatinine is at least as good a marker of dietary protein intake as urinary nitrogen and is easier to quantitate in nutrition intervention trials. PMID:23438496

  15. Comparison of Carbonate and Uricase-Carbonate Methods for the Determination of Uric Acid in Serum

    Microsoft Academic Search

    Wendell T. Caraway; Herman Marable

    1965-01-01

    A colorimetric carbonate procedure for the determination of uric acid has been modi- fied to include incubation of serum with uricase to destroy uric acid. Residual non- urate chromogens are subtracted from total chromogens to obtain the concentration of \\

  16. Calorimetric enzymic measurement of uric acid in serum.

    PubMed

    Rehak, N N; Janes, G; Young, D S

    1977-02-01

    Uric acid in serum was determined calorimetrically with a batch type microcalorimeter, by measuring the heat evolved during a coupled uricase/catalase enzymic reaction in tris(hydroxymethyl)aminomethane HCl buffer (pH 9.0 at 30 degrees C). Heat evolution and concentration are linearly related through the physiological range of serum uric acid concentrations and the method is free of interferences of the sort encountered with spectrophotometric methods. Precision and accuracy are good (CV, 2%) and the results correlate well with those obtained by a mechanized colorimetric uricase/peroxidase system. PMID:832382

  17. Serum uric acid correlates with extracellular superoxide dismutase activity in patients with chronic heart failure

    Microsoft Academic Search

    Hernan Alcaino; Douglas Greig; Mario Chiong; Hugo Verdejo; Rodrigo Miranda; Roberto Concepcion; José Luis Vukasovic; Guillermo Diaz-Araya; Rosemarie Mellado; Lorena Garcia; Daniela Salas; Leticia Gonzalez; Ivan Godoy; Pablo Castro; Sergio Lavandero

    Increased serum uric acid has been identified as an independent risk factor for cardiovascular disease. However, because of its antioxidant capacity, uric acid may play a beneficial role in endothelial function. This paradoxical relationship between uric acid and endothelial function in chronic heart failure patients remains poorly understood. Thirty-eight chronic heart failure patients (New York Heart Association functional class II-III,

  18. Uric Acid in Hypertension and Renal Disease: The Chicken or the Egg?

    Microsoft Academic Search

    Mehmet Kanbay; Yalcin Solak; Ekrem Dogan; Miguel A. Lanaspa; Adrian Covic

    2010-01-01

    After uric acid was recognized as the causative factor in gout, increased prevalence of renal disease and hypertension in this patient population caught the attention of the medical community. Thus, it has been proposed that uric acid might have caused these disorders. However, uric acid suffered a long period of ignorance in which it was considered a metabolically inert substance.

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

    Microsoft Academic Search

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

    2011-01-01

    Background: An elevated serum uric acid level is strongly associated with endothelial dysfunction and inflammation, both of which are common in chronic kidney disease (CKD). We hypothesized that endothelial dysfunction in subjects with CKD would correlate with uric acid levels. Materials and Methods: We evaluated the association between serum uric acid level and ultrasonographic flow-mediated dilatation (FMD) in 263 of

  20. Could uric acid have a pathogenic role in pre-eclampsia?

    Microsoft Academic Search

    Annabel C. Martin; Mark A. Brown

    2010-01-01

    Interest has been renewed over the role of uric acid in the pathogenesis of hypertension, endothelial dysfunction and renal dysfunction, which are all features of pre-eclampsia. Uric acid is not a consistent predictive factor for the development of pre-eclampsia but its levels generally increase once the disease manifests, and plasma levels of uric acid approximately correlate with disease severity. Hyperuricemia

  1. Urea dewaxing of naphthene oils

    SciTech Connect

    Mead, Th. C.; Wright, J. H.

    1985-03-12

    In an improved urea dewaxing process a urea/alcohol slurry chilled to 60/sup 0/ F. to 65/sup 0/ F. is added to a naphthenic distillate chilled to 60/sup 0/ F. to 65/sup 0/ F. to produce a refrigerator oil with improved low temperature properties.

  2. Fenofibrate Increases Creatininemia by Increasing Metabolic Production of Creatinine

    Microsoft Academic Search

    Carine Hottelart; Najeh El Esper; Françoise Rose; Jean-Michel Achard; Albert Fournier

    2002-01-01

    Fenofibrate is a potent hypolipemic agent, widely used in patients with renal insufficiency in whom dyslipidemia is frequent. A moderate reversible increase in creatinine plasma levels is an established side effect of fenofibrate therapy, which mechanism remains unknown. We have previously reported that in 13 patients with normal renal function or moderate renal insufficiency, two weeks of fenofibrate therapy increased

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

    ERIC Educational Resources Information Center

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

    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…

  4. Type 2 Diabetes Increases the Risk for Uric Acid Stones

    Microsoft Academic Search

    Michel Daudon; Olivier Traxer; Pierre Conort; Bernard Lacour; Paul Jungers; Hopital Tenon; Groupe Hospitalier Pitie

    An increased prevalence of nephrolithiasis has been reported in patients with diabetes. Because insulin resistance, charac- teristic of the metabolic syndrome and type 2 diabetes, results in lower urine pH through impaired kidney ammoniagenesis and because a low urine pH is the main factor of uric acid (UA) stone formation, it was hypothesized that type 2 diabetes should favor the

  5. Uric Acid as a Marker of Kidney Disease: Review of the Current Literature

    PubMed Central

    Giordano, Christin; Karasik, Olga; King-Morris, Kelli; Asmar, Abdo

    2015-01-01

    Uric acid has been implicated in the pathophysiology of renal disease; however renal clearance makes a causal relationship difficult to prove. We examine the current literature to support a potential role of uric acid in the development of kidney disease and to determine the potential to use uric acid as a marker for future renal decline. After review, we conclude that uric acid is definitively linked to the development of chronic kidney disease and can be a poor prognostic factor for the development of acute renal failure, as well. However, further human research is needed before predictive models utilizing uric acid can be developed and used in the clinical setting.

  6. 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

    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

    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

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

    E-print Network

    Mandelbaum, Tal

    Purpose: The observation periods and thresholds of serum creatinine and urine output defined in the Acute Kidney Injury Network (AKIN) criteria were not empirically derived. By continuously varying creatinine/urine output ...

  8. Uric Acid and Dementia in Community-Dwelling Older Persons

    Microsoft Academic Search

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

    2009-01-01

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

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

    PubMed Central

    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

    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

  10. Uric Acid as a Target of Therapy in CKD

    PubMed Central

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

    2012-01-01

    The prevalence of chronic kidney disease (CKD) has risen and will continue to rise in the United States and worldwide. This is alarming considering that CKD remains an irreversible condition and patients who progress to chronic kidney failure suffer reduced quality of life and high mortality rates. As such, it is imperative to identify modifiable risk factors to develop strategies to slow CKD progression. One such factor is hyperuricemia. Recent observational studies have associated hyperuricemia with kidney disease. In addition, hyperuricemia is largely prevalent in patients with CKD. Data from experimental studies have revealed several potential mechanisms by which hyperuricemia may contribute to the development and progression of CKD. In this manuscript we offer a critical review of the experimental evidence linking hyperuricemia to CKD, we highlight the gaps in our knowledge on the topic as it stands today, and we review the observational and interventional studies that have examined the potential nephro-protective effect of lowering uric acid in CKD patients . While uric acid may also be linked to cardiovascular disease and mortality in patients with CKD, this review will focus only on uric acid as a potential therapeutic target to prevent kidney disease onset and progression. PMID:23058478

  11. Effects of sitagliptin on the serum creatinine in Japanese type 2 diabetes.

    PubMed

    Maeda, Hajime; Kubota, Akira; Kanamori, Akira; Tanaka, Yasushi; Terauchi, Yasuo; Matsuba, Ikuro

    2015-06-01

    We found a slight elevation of serum creatinine in the subjects treated with sitagliptin for 2 years and a correlation between creatinine elevation and HbA1c reduction. These results suggest that creatinine elevation is associated with activation of incretin, most possibly with up-regulation of diuretic activity of GLP-1. PMID:25836945

  12. Acute uric acid nephropathy in two gouty patients with moderate hyperuricemia and high urine acidity.

    PubMed

    Hess, B; Binswanger, U

    1990-09-01

    Acute uric acid nephropathy has been described almost uniformly in patients with massive uric acid overload (malignancies with rapid cell destruction, epileptic seizures). Severe hyperuricosuria and intratubular uric acid precipitation result. Here we present two patients with gout, normal uric acid production, and moderate hyperuricemia, both of whom developed acute uric acid nephropathy. Because of pronounced urine acidity (pH values of 4.6 and 5.0 in morning fasting urines), supersaturation with respect to undissociated uric acid exceeded solubility (0.54 mmol/l), despite basal urate secretions of less than 2.2 mmol/24 hours. Additional predisposing factors, such as uricosuric treatment, heavy beer-drinking, over-consumption of purine-rich foods, and hot environment, were superimposed in both cases. PMID:2214614

  13. Update on the Pathophysiology and Management of Uric Acid Renal Stones

    Microsoft Academic Search

    Jon-Emile S. Kenny; David S. Goldfarb

    2010-01-01

    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

  14. Soluble Neuroprotective Antioxidant Uric Acid Analogs Ameliorate Ischemic Brain Injury in Mice

    Microsoft Academic Search

    Frank Haberman; Sung-Chun Tang; Thiruma V. Arumugam; Dong-Hoon Hyun; Qian-Sheng Yu; Roy G. Cutler; Zhihong Guo; Harold W. Holloway; Nigel H. Greig; Mark P. Mattson

    2007-01-01

    Uric acid is a major antioxidant in the blood of humans that can protect cultured neurons against oxidative and metabolic\\u000a insults. However, uric acid has a very low solubility which compromises its potential clinical use for neurodegenerative disorders.\\u000a Here we describe the synthesis, characterization and preclinical development of neuroprotective methyl- and sulfur-containing\\u000a analogs of uric acid with increased solubility. In vitro

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  16. Elevated levels of plasma uric acid and its relation to hypertension in arsenic-endemic human individuals in Bangladesh.

    PubMed

    Huda, Nazmul; Hossain, Shakhawoat; Rahman, Mashiur; Karim, Md Rezaul; Islam, Khairul; Mamun, Abdullah Al; Hossain, Md Imam; Mohanto, Nayan Chandra; Alam, Shahnur; Aktar, Sharmin; Arefin, Afroza; Ali, Nurshad; Salam, Kazi Abdus; Aziz, Abdul; Saud, Zahangir Alam; Miyataka, Hideki; Himeno, Seiichiro; Hossain, Khaled

    2014-10-01

    Blood uric acid has been recognized as a putative marker for cardiovascular diseases (CVDs). CVDs are the major causes of arsenic-related morbidity and mortality. However, the association of arsenic exposure with plasma uric acid (PUA) levels in relation to CVDs has not yet been explored. This study for the first time demonstrated the associations of arsenic exposure with PUA levels and its relationship with hypertension. A total of 483 subjects, 322 from arsenic-endemic and 161 from non-endemic areas in Bangladesh were recruited as study subjects. Arsenic concentrations in the drinking water, hair and nails of the study subjects were measured by inductively coupled plasma mass spectroscopy. PUA levels were measured using a colorimetric method. We found that PUA levels were significantly (p<0.001) higher in males and females living in arsenic-endemic areas than those in non-endemic area. Arsenic exposure (water, hair and nail arsenic) levels showed significant positive correlations with PUA levels. In multiple regression analyses, arsenic exposure levels were found to be the most significant contributors on PUA levels among the other variables that included age, body mass index, blood urea nitrogen, and smoking. There were dose-response relationships between arsenic exposure and PUA levels. Furthermore, diastolic and systolic blood pressure showed significant positive correlations with PUA levels. Finally, the average PUA levels were significantly higher in the hypertensive group than those in the normotensive group in both males and females living in arsenic-endemic areas. These results suggest that arsenic exposure-related elevation of PUA levels may be implicated in arsenic-induced CVDs. PMID:25281834

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

    PubMed Central

    Sabater, David; Arriarán, Sofía; Fernández-López, José-Antonio; Romero, María del Mar; Remesar, Xavier

    2014-01-01

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

  18. Regulation of urea uptake in Pseudomonas aeruginosa

    Microsoft Academic Search

    Thomas Jahns

    1992-01-01

    The energy-dependent urea permease was studied in two strains ofPseudomonas aeruginosa, measuring the uptake (transport and metabolism) of14C-urea. In both strains urea uptakein vivo and urease activityin vitro differed significantly with respect to kinetic parameters, temperature and pH dependence and response to metabolic inhibitors. Ammonium strongly interfered both with the expression of the urea uptake system and its activity. The

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

    PubMed Central

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

    2014-01-01

    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

  20. Association of Serum Uric Acid with Body Mass Index: A Cross-Sectional Study from Jiangsu Province, China

    PubMed Central

    WANG, Honggang; WANG, Lizhen; XIE, Rui; DAI, Weijie; GAO, Chengcheng; SHEN, Peng; HUANG, Xiaodan; ZHANG, Faming; YANG, Xiaozhong; JI, Guozhong

    2014-01-01

    Abstract Background Body mass index (BMI) has been demonstrated to be associated with serum uric acid (SUA) level in many developed countries, however, there is still a lack of large sample study in Jiangsu Province, one of the most economically developed regions in China, where fat-rich diet is common. Methods Through retrospective analysis in healthy subjects, we determined the association of BMI with hyperuricemia risk. Data of 39,736 participants from January 2011 to June 2013 in China were analyzed for parameters including physical examinations and biochemical blood analysis. Results On univariate analysis, SUA was positively correlated with age, SBP, DBP, BMI, FPG, red blood cell count, hemoglobin, white blood cell count, platelet, cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, ALT, AST, bilirubin, albumin, BUN and creatinine. SUA was significantly elevated in a linear fashion as BMI increased, and SUA in obesity was significantly higher than underweight. The prevalence of hyperuricemia remained approximately 2.98 times greater among individuals with overweight, and 5.96 times greater among obesity, compared to individuals with underweight. Conclusion There is a positive relationship between BMI and SUA among healthy subjects in Jiangsu province, China.

  1. Uric acid modulates vascular endothelial function through the down regulation of nitric oxide production.

    PubMed

    Papežíková, I; Pekarová, M; Kolá?ová, H; Klinke, A; Lau, D; Baldus, S; Lojek, A; Kubala, L

    2013-02-01

    Endothelial dysfunction characterized by decreased nitric oxide (NO) bioavailability is the first stage of coronary artery disease. It is known that one of the factors associated with an increased risk of coronary artery disease is a high plasma level of uric acid. However, causative associations between hyperuricaemia and cardiovascular risk have not been definitely proved. In this work, we tested the effect of uric acid on endothelial NO bioavailability. Electrochemical measurement of NO production in acetylcholine-stimulated human umbilical endothelial cells (HUVECs) revealed that uric acid markedly decreases NO release. This finding was confirmed by organ bath experiments on mouse aortic segments. Uric acid dose-dependently reduced endothelium-dependent vasorelaxation. To reveal the mechanism of decreasing NO bioavailability we tested the effect of uric acid on reactive oxygen species production by HUVECs, on arginase activity, and on acetylcholine-induced endothelial NO synthase phosphorylation. It was found that uric acid increases arginase activity and reduces endothelial NO synthase phosphorylation. Interestingly, uric acid significantly increased intracellular superoxide formation. In conclusion, uric acid decreases NO bioavailability by means of multiple mechanisms. This finding supports the idea of a causal association between hyperuricaemia and cardiovascular risk. PMID:23136942

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

    PubMed

    Kang, Duk-Hee; Ha, Sung-Kyu

    2014-06-01

    Hyperuricemia is known to be associated with the presence of cardiovascular and metabolic syndrome and with the development of incipient kidney disease and an accelerated renal progression. However, an elevated uric acid level was not generally regarded as a true etiology or mediator, but an indicator of these diseases. Uric acid has recently regained the clinical interest and popularity based on emerging data suggesting the causative role of hyperuricemia in cardiovascular and renal disease. Experimental data demonstrates oxidative stress is one of the earliest phenomena observed in vascular, renal, liver cells and adipocytes exposed to uric acid. Since uric acid is one of the major antioxidants of plasma acting as a free radical scavenger and a chelator of transitional metal ion, uric acid-induced oxidative stress seems paradoxical. Data regarding the clinical implication of hyperuricemia is even more confusing, which defines hyperuricemia as a useless parameter to be eliminated from routine follow-up or a major risk factor to be therapeutic target. With a review of experimental and epidemiologic data, the presence of molecular switch to regulate the role of uric acid as anti- or pro-oxidant in different compartment of our body is suggested, which may shed light on understanding the paradoxical role of uric acid and solving the "uric acid debate". PMID:25061467

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

    PubMed Central

    Kang, Duk-Hee

    2014-01-01

    Hyperuricemia is known to be associated with the presence of cardiovascular and metabolic syndrome and with the development of incipient kidney disease and an accelerated renal progression. However, an elevated uric acid level was not generally regarded as a true etiology or mediator, but an indicator of these diseases. Uric acid has recently regained the clinical interest and popularity based on emerging data suggesting the causative role of hyperuricemia in cardiovascular and renal disease. Experimental data demonstrates oxidative stress is one of the earliest phenomena observed in vascular, renal, liver cells and adipocytes exposed to uric acid. Since uric acid is one of the major antioxidants of plasma acting as a free radical scavenger and a chelator of transitional metal ion, uric acid-induced oxidative stress seems paradoxical. Data regarding the clinical implication of hyperuricemia is even more confusing, which defines hyperuricemia as a useless parameter to be eliminated from routine follow-up or a major risk factor to be therapeutic target. With a review of experimental and epidemiologic data, the presence of molecular switch to regulate the role of uric acid as anti- or pro-oxidant in different compartment of our body is suggested, which may shed light on understanding the paradoxical role of uric acid and solving the "uric acid debate". PMID:25061467

  4. Observations on Serum Uric Acid Levels and the Risk of Idiopathic Parkinson's Disease

    Microsoft Academic Search

    J. W. Davis; A. Grandinetti; C. I. Waslien; G. W. Ross; L R. White; D. M. Morens

    Uric acid, an antioxidant found in high concentrations in serum and in the brain, has been hypothesized to protect against oxidative damage and cell death in Parkinson's disease. The authors tested this hypothesis among men participating in a 30-year prospective study known as the Honolulu Heart Program. Serum uric acid was measured in 7,968 men at the baseline examination held

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

    PubMed

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

    2013-09-20

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

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

    Microsoft Academic Search

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

    1997-01-01

    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

  7. Effect of prilled urea and modified urea materials on yield and quality of geranium ( Pelargonium graveolens L. Her.)

    Microsoft Academic Search

    B. R. Rajeswara Rao; Kailash Singh; A. K. Bhattacharya; A. A. Naqvi

    1990-01-01

    Two field experiments were conducted to study the effect of prilled urea, neem cake coated urea, dicyandiamide treated urea and urea supergranules applied to a perennial aromatic herb, geranium (Pelargonium graveolens L. Her'.) grown on a sandy loam soil. Application of nitrogen increased the biomass and essential oil yields. Neem cake coated urea significantly increased the yields over prilled urea.

  8. Regulation of uric acid excretion by the kidney.

    PubMed

    Lipkowitz, Michael S

    2012-04-01

    It has been known for many years that the kidney plays a major role in uric acid homeostasis, as more than 70% of urate excretion is renal. Furthermore, hyperuricemia in gout is most commonly the result of relative urate underexcretion, as the kidney has enormous capacity for urate reabsorption. A clear understanding of the mechanisms of renal handling of urate has been hampered by the differences between humans and animal models. The power of human genetics and genome-wide association studies has now provided new insight into the molecular mechanisms of urate transport by identifying the transporters that have critical roles in urate transport. This review surveys the new evidence for a molecular model of urate transport in the renal proximal tubule and uses these data to refute the popular four-component model for urate transport that has long been in vogue. It also discusses data that help us understand the relation of diuretics to hyperuricemia, losartan-induced uricosuria, variations in uric acid levels in hyperglycemia, and the effects of dairy diets on serum urate levels. In the end, several of these clinical findings are explained, and the remaining gaps in our knowledge will become evident. PMID:22359229

  9. Rare mutations associating with serum creatinine and chronic kidney disease.

    PubMed

    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

    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

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

    PubMed Central

    Dawson, Jesse; Walters, Matthew

    2006-01-01

    Serum uric acid may be an independent risk factor for cardiovascular disease. This review examines this association, potential mechanisms, and explores whether strategies to reduce uric acid will improve outcomes. The recent studies of xanthine oxidase inhibition are given particular focus. Epidemiological evidence supports the theory that uric acid is an independent risk factor for cardiovascular disease. Recent studies of losartan, atorvastatin and fenofibrate suggest that uric acid reduction contributes to the risk reduction offered by these therapies. Several small studies of xanthine oxidase inhibition have shown improvements in measures of cardiovascular function of a similar magnitude to that of other proven preventative treatments. These trial data and the convincing epidemiological evidence mandate that large clinical trials of uric acid-lowering strategies are performed in patients with or at high risk of cardiovascular disease. If such approaches are shown to be effective in reducing cardiovascular events, they would represent a novel and cost-effective preventative approach. PMID:21894646

  11. Structure and properties of urea-plasticized starch films with different urea contents.

    PubMed

    Wang, Jia-Li; Cheng, Fei; Zhu, Pu-Xin

    2014-01-30

    Films of thermoplastic starch (TPS) plasticized with different contents of urea were prepared by using a solution casting method. Scanning electron microscopy, X-ray diffraction and IR spectroscopy were used to characterize structures of the TPS films, respectively. Water vapor sorption isotherms and tensile properties of the films were determined. TPS films showed more smooth and transparent in appearance and less B-type crystallinity than the starch film without urea. The effect of urea content on the structure and behavior of the TPS film could be divided in three stages: (1) below urea 10% where urea interacted with starch via H-bonding and the films showed an antiplasticization effect, (2) from urea 10% to 30% where an apparent plasticization effect appeared on the starch because of free urea molecules as the effective plasticizer, and (3) a macroscopic phase separation occurred due to supersaturation of urea when urea content was more than 30%. PMID:24299881

  12. Urea biosensor for hemodialysis monitoring

    DOEpatents

    Glass, R.S.

    1999-01-12

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

  13. Urea biosensor for hemodialysis monitoring

    DOEpatents

    Glass, Robert S. (Livermore, CA)

    1999-01-01

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

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

    PubMed Central

    West, Caroline E.; Rhodes, Blaine N.

    2014-01-01

    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. PMID:25614740

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

    PubMed Central

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

    2014-01-01

    Background: Excess serum uric acid (UA) accumulation can lead to various diseases. Increasing evidences reveal that UA may have a key role in the pathogenesis of metabolic syndrome. Little is known about the associations of UA levels with cardiometabolic risk factors in prediabetic individuals. This study was designed to evaluate the association between UA and cardiometabolic risk factors in prediabetic subjects with family history of diabetes compared with those with normal glucose tolerance (NGT). Materials and Methods: In a cross-sectional setting, a sample containing 643 (302 prediabetic subjects and 341 normal) of the first-degree relatives of diabetic patients aged 35-55-years old were investigated. Samples were assessed in prediabetic and normal groups using glucose tolerance categories. Prediabetes was defined based on American Diabetes Association (ADA) criteria. Body weight and height, systolic and diastolic blood pressure (SBP and DBP), UA, creatinine (Cr), albumin (Alb), fasting blood glucose (FBG), hemoglobin A1c (HbA1c), and lipid profiles were measured and compared between two groups. Results: Prediabetic persons were older and obese than normal persons. Also, prediabetic persons (5.2 ± 1.3 mg/dl) had significantly higher UA than normal persons (4.9 ± 1.4 mg/dl) (P < 0.05). FBG after 0, 30, 60, and 120 min in prediabetic were higher than normal persons (P < 0.001). With respect to metabolic parameters, the patients in the higher UA quartiles exhibited higher levels of body mass index (BMI), SBP, FBG and triglycerides (TG). The higher quartiles of UA tended to be associated with higher BMI and higher total cholesterol (TC) in females prediabetic persons. Based on logistic regression analysis in different models, UA was positively (odds ratio (OR) >1, P < 0.05) associated with glucose tolerance categories. This association remained statistically significant after adjusting the effects of age and BMI. Also, the association between glucose tolerance categories and UA were positively significant in both genders. Conclusion: High UA level was associated with some cardiometabolic risk factors in prediabetic individuals compared with normal person. UA level was also a significant predictor for prediabetes condition. PMID:24949036

  16. Some factors in liquid supplements affecting urea toxicity 

    E-print Network

    McClain, William Ray

    1979-01-01

    Experiment 1: Site of Rumen Sampling Experiment 2: Determination of Lethal Levels of Urea in Molasses-Urea or Water-Urea Solutions Sheep Work Cattle Work Experiment 3: Effect of Repetitive Doses of Urea on Toxicity Pooled Data of Experiments 2 and 3... DOSE OF UREA (SHEEP) COMPOSITION OF MAINTENANCE RATION (CATTLE). TREATMENT AND LEVEL OF INITIAL DOSE OF UREA (CATTLE) ~Pa e 15 18 19 TREATMENT, TIME INTERVAL, AND LEVEL OF UREA DRENCHED IN REPETITIVE DOSAGE EXPERIMENT 21 EFFECT OF THREE...

  17. Urea transformation of wetland microbial communities.

    PubMed

    Thorén, Ann-Karin

    2007-02-01

    Transformation of urea to ammonium is an important link in the nitrogen cycle in soil and water. Although microbial nitrogen transformations, such as nitrification and denitrification, are well studied in freshwater sediment and epiphytic biofilm in shallow waters, information about urea transformation in these environments is scarce. In this study, urea transformation of sedimentary, planktonic, and epiphytic microbial communities was quantified and urea transformation of epiphytic biofilms associated with three different common wetland macrophyte species is compared. The microbial communities were collected from a constructed wetland in October 2002 and urea transformation was quantified in the laboratory at in situ temperature (12 degrees C) with the use of the 14C-urea tracer method, which measures the release of 14CO2 as a direct result of urease activity. It was found that the urea transformation was 100 times higher in sediment (12-22 mmol urea-N m(-2) day(-1)) compared with the epiphytic activity on the surfaces of the submerged plant Elodea canadensis (0.1-0.2 mmol urea-N m(-2) day(-1)). The epiphytic activity of leaves of Typha latifolia was lower (0.001-0.03 mmol urea-N m(-2) day(-1)), while urea transformation was negligible in the water column and on the submerged leaves of the emergent plant Phragmites australis. However, because this wetland was dominated by dense beds of the submerged macrophyte E. canadensis, this plant provided a large surface area for epiphytic microbial activity-in the range of 23-33 m2 of plant surfaces per square meter of wetland. Thus, in the wetland system scale at the existing plant distribution and density, the submerged plant community had the potential to transform 2-7 mmol urea-N m(-2) day(-1) and was in the same magnitude as the urea transformation in the sediment. PMID:17268879

  18. Molecularly imprinted titania nanoparticles for selective recognition and assay of uric acid

    NASA Astrophysics Data System (ADS)

    Mujahid, Adnan; Khan, Aimen Idrees; Afzal, Adeel; Hussain, Tajamal; Raza, Muhammad Hamid; Shah, Asma Tufail; uz Zaman, Waheed

    2015-06-01

    Molecularly imprinted titania nanoparticles are su ccessfully synthesized by sol-gel method for the selective recognition of uric acid. Atomic force microscopy is used to study the morphology of uric acid imprinted titania nanoparticles with diameter in the range of 100-150 nm. Scanning electron microscopy images of thick titania layer indicate the formation of fine network of titania nanoparticles with uniform distribution. Molecular imprinting of uric acid as well as its subsequent washing is confirmed by Fourier transformation infrared spectroscopy measurements. Uric acid rebinding studies reveal the recognition capability of imprinted particles in the range of 0.01-0.095 mmol, which is applicable in monitoring normal to elevated levels of uric acid in human blood. The optical shift (signal) of imprinted particles is six times higher in comparison with non-imprinted particles for the same concentration of uric acid. Imprinted titania particles have shown substantially reduced binding affinity toward interfering and structurally related substances, e.g. ascorbic acid and guanine. These results suggest the possible application of titania nanoparticles in uric acid recognition and quantification in blood serum.

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

    PubMed

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

    2011-04-01

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

  20. The association of vitamin C, alcohol, coffee, tea, milk and yogurt with uric acid and gout.

    PubMed

    Towiwat, Patapong; Li, Zhan-Guo

    2015-06-01

    About 2500 years ago, gout was observed by Hippocrates and many people suffered severe pain and deformity. Lifestyle and diet play a significant role in gout and serum uric acid levels. Epidemiological and research studies have supported this evidence. Many recommendations and guidelines from different parts of the world mention the impact of diet on gout. Recently, new research has shown associations between vitamin C, alcohol, coffee, tea, milk and yogurt with uric acid and the risk of gout. Our review summarizes recently published research regarding dietary impact on the risk of gout and serum uric acid levels. PMID:26082349

  1. Urea Transformation of Wetland Microbial Communities

    Microsoft Academic Search

    Ann-Karin Thorén

    2007-01-01

    Transformation of urea to ammonium is an important link in the nitrogen cycle in soil and water. Although microbial nitrogen\\u000a transformations, such as nitrification and denitrification, are well studied in freshwater sediment and epiphytic biofilm\\u000a in shallow waters, information about urea transformation in these environments is scarce. In this study, urea transformation\\u000a of sedimentary, planktonic, and epiphytic microbial communities was

  2. Factors influencing urea space estimates in goats

    Microsoft Academic Search

    A. Asmare; L. J. Dawson; R. Puchala; T. A. Gipson; M. Villaquiran; I. Tovar-Luna; G. Animut; T. Ngwa; T. Sahlu; R. C. Merkel; A. L. Goetsch

    2007-01-01

    Female Alpine goats, 18 approximately 17 months of age (yearling) and 18 approximately 5-month-old (growing), were used in an experiment to determine effects of animal age, urea dose (100, 130, and 160mg\\/kg BW), and time without feed and water (shrink; 0, 16, and 24h) on urea space (US) estimates. A 20% (w\\/v) urea solution was infused into a jugular vein,

  3. Low Temperature Urea Decomposition and SCR Performance

    Microsoft Academic Search

    C. Scott Sluder; John M. E. Storey; Samuel A. Lewis; Linda A. Lewis

    Urea-SCR systems are potentially a highly-effective means of NOX reduction for light-duty diesel vehicles. However, use of urea-SCR technologies at low temperatures presents unique technical challenges. This study was undertaken to provide more knowledge about low temperature urea decomposition and the resulting effects on SCR performance. Data are presented for experiments using two SCR catalysts of differing size with a

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

    Microsoft Academic Search

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

    2009-01-01

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

  5. Automated urinalysis technique determines concentration of creatine and creatinine by colorimetry

    NASA Technical Reports Server (NTRS)

    Rho, J. H.

    1967-01-01

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

  6. Substituted Ureas. Methods of Synthesis and Applications

    NASA Astrophysics Data System (ADS)

    Vishnyakova, T. P.; Golubeva, I. A.; Glebova, E. V.

    1985-03-01

    Systematic data on the method of synthesis of ureas by the interaction of compounds containing the amino-group with organic isocyanates, of amines and alkyl halides with alkali metal cyanates, and of primary and secondary amines with phosgene, carbon dioxide, urea, or nitrourea and by the carbonylation of amines are presented. The reactions involving the alkylation of urea and its interaction with various compounds containing functional groups are considered. The advantages and disadvantages of various methods are noted. The principal and practical applications of substituted ureas, including their applications as additives to organic materials, are discussed. The bibliography includes 314 references.

  7. Increasing urea-N efficiency in transplanted lowland rice by urea solution band placement

    Microsoft Academic Search

    P. Devasenapathy; S. P. Palaniappan

    1996-01-01

    Alternative N fertiliser management strategies are needed to increase N-use efficiency in wetland rice (Oryza sativa L.). In the wet season of 1993–1994, field experiments were conducted to evaluate the band placement of urea solution in comparison with broadcast prilled urea, neem-coated urea, or point-placement of urea supergranules. Both grain yield and N-use efficiency were higher with band placement of

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

    PubMed

    Najafi, Mahdi

    2014-09-26

    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

  9. The GLUT9 Gene Is Associated with Serum Uric Acid Levels

    E-print Network

    Abecasis, Goncalo

    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

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

    NASA Astrophysics Data System (ADS)

    Zhang, Tiliang; Sun, Xiangying; Liu, Bin

    2011-09-01

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

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

    PubMed Central

    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

    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

  12. Bilateral Uric Acid Nephrolithiasis and Ureteral Hypertrophy in a Free-ranging River Otter (Lontra canadensis)

    Microsoft Academic Search

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

    2003-01-01

    We report the first case of uric acid nephrolithiasis in a free-ranging river otter (Lontra canadensis ). A7y r oldmale river otter collected from the Skagit River of western Washington (USA) had bilateral nephrolithiasis and severely enlarged ureters (one of 305 ex- amined (0.33%)). The uroliths were 97% uric acid and 3% protein. Microscopic changes in the kidney were confined

  13. Uric Acid Spherulites in the Reflector Layer of Firefly Light Organ

    PubMed Central

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

    2013-01-01

    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

  14. The impact of serum uric acid on cardiovascular outcomes in the LIFE study

    Microsoft Academic Search

    AUD HŘIEGGEN; Michael H. Alderman; Sverre E. Kjeldsen; STEVO JULIUS; Richard B. Devereux; ULF DE FAIRE; FREJ FYHRQUIST; HANS IBSEN; KRISTER KRISTIANSON; OLE LEDERBALLE-PEDERSEN; Lars H. Lindholm; Markku S. Nieminen; PER OMVIK; SUZANNE OPARIL; HANS WEDEL; CONG CHEN; BJÖRN DAHLÖF

    2004-01-01

    The impact of serum uric acid on cardiovascular outcomes in the LIFE study.BackgroundThe Losartan Intervention For Endpoint reduction in hypertension (LIFE) study demonstrated the superiority of a losartan-based regimen over atenolol-based regimen for reduction of cardiovascular (CV) morbidity and mortality. It has been suggested that the LIFE study results may be related to the effects of losartan on serum uric

  15. Identification of low-frequency variants associated with gout and serum uric acid levels

    Microsoft Academic Search

    Daniel F Gudbjartsson; G Bragi Walters; Hafdis T Helgadottir; Agnar Helgason; Sigurjon A Gudjonsson; Carlo Zanon; Soren Besenbacher; Gyda Bjornsdottir; Olafur T Magnusson; Gisli Magnusson; Eirikur Hjartarson; Jona Saemundsdottir; Arnaldur Gylfason; Adalbjorg Jonasdottir; Hilma Holm; Ari Karason; Thorunn Rafnar; Hreinn Stefansson; Ole A Andreassen; Jesper H Pedersen; Allan I Pack; Marieke C H de Visser; Lambertus A Kiemeney; Arni J Geirsson; Gudmundur I Eyjolfsson; Isleifur Olafsson; Augustine Kong; Gisli Masson; Helgi Jonsson; Unnur Thorsteinsdottir; Ingileif Jonsdottir; Patrick Sulem; Kari Stefansson

    2011-01-01

    We tested 16 million SNPs, identified through whole-genome sequencing of 457 Icelanders, for association with gout and serum uric acid levels. Genotypes were imputed into 41,675 chip-genotyped Icelanders and their relatives, for effective sample sizes of 968 individuals with gout and 15,506 individuals for whom serum uric acid measurements were available. We identified a low-frequency missense variant (c.1580C>G) in ALDH16A1

  16. Higher Serum Uric Acid on Admission Is Associated with Higher Short-term Mortality and Poorer Long-term Survival After Myocardial Infarction: Retrospective Prognostic Study

    PubMed Central

    Car, Siniša; Trkulja, Vladimir

    2009-01-01

    Aim To assess serum uric acid (SUA) levels determined on admission as a potential predictor of short-term mortality and long-term survival in acute myocardial infarction (AMI) patients. Method Data for this retrospective prognostic study were drawn from the patient database of the Varaždin County General Hospital in Varaždin, Croatia. We included consecutive patients with verified AMI admitted within 48 hours since the symptom onset during the period between January 1, 1996 and December 31, 2001. Long-term survival/mortality data were collected through direct contacts with patients and search of the community death registries. Relative risks (RR) and hazard ratios (HR) by 10 µmol/L increase in SUA were determined using modified Poisson regression with robust error variance and proportional hazard regression, respectively. Results A total of 621 patients (age 27-90 years, 64.7% men, 77.5% AMI with ST elevation, SUA 63-993 µmol/L) were included. Higher SUA on admission was independently associated with higher in-hospital mortality (RR, 1.016; 95% confidence interval [CI], 1.001-1.031, P?=?0.043) and higher thirty-day mortality (RR, 1.016; 95% CI, 1.003-1.029, P?=?0.018). Considered covariates were demographics, pre-index event cardiovascular morbidity and treatment, on-admission serum creatinine, total cholesterol and triglycerides, AMI characteristics, and peak creatine phosphokinase. Higher SUA on admission was also independently associated with poorer long-term survival (ie, higher all-cause mortality) (HR, 1.105; 95% CI, 1.020-1.195, P?=?0.010). Considered covariates were demographics, laboratory variables on admission, AMI characteristics, peak creatine phosphokinase, acute complications, and treatment at discharge. Conclusion Higher serum uric acid determined on admission is associated with higher in-hospital mortality and thirty-day mortality and poorer long-term survival after AMI. PMID:20017224

  17. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Urea nitrogen test system. 862.1770 Section 862...Chemistry Test Systems § 862.1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to...

  18. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Urea nitrogen test system. 862.1770 Section 862...Chemistry Test Systems § 862.1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to...

  19. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Urea nitrogen test system. 862.1770 Section 862...Chemistry Test Systems § 862.1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to...

  20. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Urea nitrogen test system. 862.1770 Section 862...Chemistry Test Systems § 862.1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to...

  1. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Urea nitrogen test system. 862.1770 Section 862...Chemistry Test Systems § 862.1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to...

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

    PubMed

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

    2013-07-01

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

  3. Reagentless uric acid biosensor based on Ni microdiscs-loaded NiO thin film matrix.

    PubMed

    Arora, Kashima; Tomar, Monika; Gupta, Vinay

    2014-09-21

    The development of a noninvasive test for uric acid has been the holy grail of uric acid detection research over the last decade. In the present work, a novel matrix comprising of a NiO thin film (a biocompatible material) loaded with Ni microdiscs was prepared on an ITO-coated glass substrate (Ni/NiO/ITO) with the help of RF sputtering for the reagentless detection of uric acid. The bioelectrode was fabricated by immobilizing uricase using a physical adsorption technique on the surface of the Ni/NiO/ITO electrode. The prepared matrix was found to be efficient in sensing biological processes occurring on the surface of the bioelectrode (Ur/Ni/NiO/ITO) in the presence of the analyte (uric acid) to obtain an electronic output. The biosensor exhibits a high sensitivity (431.09 ?A mM(-1)), low Km value (0.15 mM), high apparent enzyme activity (5.07 × 10(-2) units per cm(2)), high shelf life (20 weeks) and good selectivity for the detection of uric acid over a wide concentration range (0.05 mM to 1 mM) without any external mediator in the PBS buffer. The obtained results are encouraging for the realization of a reagentless uric acid biosensor with efficient sensing response characteristics. PMID:25046556

  4. The role of uric acid in kidney fibrosis: experimental evidences for the causal relationship.

    PubMed

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

    2014-01-01

    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

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

    PubMed

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

    2013-04-01

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

  6. Urea transport through composite polyallylamine membranes

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    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.

  7. Prognostic value of serum creatinine levels in children with posterior urethral valves treated by primary valve ablation

    Microsoft Academic Search

    Osama Sarhan; Khaled El-Dahshan; Mohamed Sarhan

    2010-01-01

    PurposeWe evaluated the prognostic value of serum creatinine level at presentation and nadir creatinine during follow up for future renal function (RF) in children with posterior urethral valves (PUV).

  8. Total-body skeletal muscle mass: evaluation of 24-h urinary creatinine excretion by computerized axial tomography13

    Microsoft Academic Search

    Zi-Mian Wang; Dympna Gallagher; Miriam E Nelson; Dwight E Matthews; Steven B Heymsfield

    A classic body-composition method is estima- tion of total-body skeletal muscle mass (SM, in kg) from 24-h urinary creatinine excretion (in g). Two approaches of unknown validity have been used to calculate SM from creatinine: one assumes a constant ratio of SM to creatinine, the so-called creat- mine equivalence (k), and that SM = k X creatinine; the other suggests

  9. Toxicologic evaluation of acute and subacute oral administration of Cucurbita maxima seed extracts to rats and swine.

    PubMed

    de Queiroz-Neto, A; Mataqueiro, M I; Santana, A E; Alessi, A C

    1994-06-01

    The extract prepared from dried seeds of Cucurbita maxima was administered to rats and pigs. Following a single dose or 4 weeks of daily oral administration, the extract produced no changes in serum glucose, urea, creatinine, total protein, uric acid, GOT, GPT, LDH or blood counts. Urine analysis (urea, uric acid, creatinine, total protein, Na and K), as well as histopathological investigation, showed no abnormalities. These results taken as a whole indicate that the seeds of C. maxima as used in Brazilian folk medicine are not toxic for rats and swine. PMID:7967649

  10. Rapid dissolution of cellulose in LiOH/urea and NaOH/urea aqueous solutions.

    PubMed

    Cai, Jie; Zhang, Lina

    2005-06-24

    Rapid dissolution of cellulose in LiOH/urea and NaOH/urea aqueous solutions was studied systematically. The dissolution behavior and solubility of cellulose were evaluated by using (13)C NMR, optical microscopy, wide-angle X-ray diffraction (WAXD), FT-IR spectroscopy, DSC, and viscometry. The experiment results revealed that cellulose having viscosity-average molecular weight ((overline) M eta) of 11.4 x 104 and 37.2 x 104 could be dissolved, respectively, in 7% NaOH/12% urea and 4.2% LiOH/12% urea aqueous solutions pre-cooled to -10 degrees C within 2 min, whereas all of them could not be dissolved in KOH/urea aqueous solution. The dissolution power of the solvent systems was in the order of LiOH/urea > NaOH/urea > KOH/urea aqueous solution. The results from DSC and (13)C NMR indicated that LiOH/urea and NaOH/urea aqueous solutions as non-derivatizing solvents broke the intra- and inter-molecular hydrogen bonding of cellulose and prevented the approach toward each other of the cellulose molecules, leading to the good dispersion of cellulose to form an actual solution. PMID:15954076

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

    Microsoft Academic Search

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

    2000-01-01

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

  12. Prediction of Glomerular Filtration Rate by Serum Creatinine and ?2Microglobulin

    Microsoft Academic Search

    Peter H. Shea; John F. Maher; Eva Horak

    1981-01-01

    The reciprocal of serum creatinine concentration (1\\/Cr) is often used to predict glomerular filtration rate (GFR). Serum creatinine also varies with age, size, and muscle mass, and so it may inaccurately estimate GFR. The reciprocal of serum ?2 -microglobulin (1\\/?2?) has been proposed as an alternative estimator of GFR. This study compares 1\\/Cr and 1\\/?2? as predictors of GFR as

  13. Disposition of plasma creatinine in non-azotaemic and moderately azotaemic cats.

    PubMed

    Le Garreres, Alain; Laroute, Valérie; De La Farge, France; Boudet, Karine G; Lefebvre, Hervé P

    2007-04-01

    The objectives of this study were to compare assay methods for plasma creatinine (Pl-creat) in cats and to describe the disposition of creatinine and iohexol in 12 healthy and moderately azotaemic cats. Exogenous creatinine and iohexol were injected simultaneously by intravenous bolus, and repeated blood samples were taken to determine the pharmacokinetic parameters of each marker. Pl-creat was assayed by high-performance liquid chromatography (HPLC), Jaffé and enzymatic methods. The enzymatic method was shown to be more reliable than the Jaffé method. Two stereoisomers, exo- and endo-iohexol were identified. The plasma clearance of creatinine (2.3+/-0.66 ml/min/kg) was significantly higher (P<0.001) than that of exo-iohexol (1.7+/-0.40 ml/min/kg). The volume of distribution (447+/-97 ml/kg) and elimination half-life (181+/-77 min) of creatinine were also higher (P<0.001) than those of exo- and endo-iohexol. The estimated daily endogenous production of creatinine was 65+/-23 mg/kg. None of the pharmacokinetic parameters was changed by the azotaemic status of the animals. PMID:17049290

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

    PubMed

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

    2015-02-01

    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

  15. Managing Urea-Containing Fertilizers1 Larry G. Bundy2

    E-print Network

    Balser, Teri C.

    of the reactions urea undergoes when added to soils. Urea is hydrolyzed or broken down to ammonia and carbon of the urea was hydrolyzed within 2 days after application at 50o F and over 80% was broken down within 4 days was hydrolyzed within 2 days at a temperature of 79o F. Alternatively, cold temperatures slow down urea

  16. Clinical Value of Plasma Creatine Kinase and Uric Acid Levels during First Week of Life

    PubMed Central

    Wharton, B. A.; Bassi, Urmilla; Gough, G.; Williams, Angela

    1971-01-01

    Levels of creatine kinase and uric acid in cord blood were variable but similar to those in maternal blood. During the first 24 hours of life there was a rise in the concentration of both substances, particularly of creatine kinase, to reach levels well above those normally found in later childhood. Thereafter there was a steady fall to stable levels around the fifth day. The causes of these obvious changes in concentration are not known. Uric acid levels during the first 24 hours were higher after a longer labour. Creatine kinase levels were lower, and uric acid levels higher in low birthweight babies. The plasma creatine kinase originated from non-cardiac muscle. Plasma creatine kinase and uric acid levels may help in the early diagnosis of rare specific disorders such as muscular dystrophy and the Lesch-Nyhan syndrome, but do not help in the diagnosis of other neurological disorders at this time of life, and give no indication of the child's prognosis, despite their occasional help in adult patients. Even with the specific syndromes, however, interpretation must be guarded. It is not known whether the high creatine kinase levels associated with Duchenne muscular dystrophy would be lost in the upper limits of the normal range for the first few days of life or whether they would be higher still. In the Lesch-Nyhan syndrome uric acid levels are well above the normal range defined in this investigation. PMID:5104539

  17. A Comparative Study of Serum Uric Acid levels and Lipid Ratios in Coronary Artery Disease Patients

    PubMed Central

    Sathiya, R.; Velu, V. Kuzhandai; Niranjan, G.; Srinivasan, A. R.; Amirtha, Ganesh B.; Ramesh, R.; Babu, M. Sathish; Saha, Subiman

    2014-01-01

    Introduction: Coronary Artery Disease (CAD) appears to be common in the Indian population of different geographical origins, religions and languages. Measurement of lipid fractions and ratios are widely recommended for risk assessment. A few studies have shown that serum uric acid plays a role in the development of cardiovascular morbidity. Very few reports are cited linking serum uric acid with the lipid fraction in CAD Objectives: To find the significance of non-HDL cholesterol, LDL-c/HDL-c ratio, TC/HDL ratio and serum uric acid level in CAD patients Subjects and Methodology: In this study, we included fifty CAD patients as subjects and an equal number of controls. Both subjects and controls were assessed for anthropometric, physiological and biochemical parameters Results: The present study showed significant increased levels of total cholesterol (p=0.002), TAGs (p<0.001), HDL (p=0.005), LDL (p<0.006) and non-HDL cholesterol (p<0.001). LDL-c/HDL-c ratio (p<0.001) and TC/HDL ratio (p<0.001) in CAD patients (subjects) were also significant when compared to controls. Uric acid level in CAD patients was increased (p<0.001). Conclusion: Serum Uric Acid, TC/HDL and LDL/HDL ratios could be regarded as objective markers, in association with existing atherogenic dyslipidemia in patients with CAD. PMID:25018681

  18. A novel flow-injection chemiluminescence determination of uric acid based on diperiodatoargentate(III) oxidation.

    PubMed

    Yang, Chunyan; Zhang, Zhujun

    2010-04-15

    A novel and high selectivity flow-injection chemiluminescence (FI-CL) system with diperiodatoargentate(III) (DPA) is developed for the determination of uric acid for the first time. It is based on the reaction of diperiodatoargentate(III) (DPA) with uric acid in alkaline medium to emit CL. With the peak height as a quantitative parameter applying optimum working conditions, the relative CL intensity was linear with the uric acid concentration in the range of 4.0 x 10(-7)-2.0 x 10(-4) mol L(-1) with a detection limit of 1.2 x 10(-7) mol L(-1) (3 sigma). The relative standard deviation (RSD) was 2.1% for 5.0 x 10(-5) mol L(-1) uric acid (n=7). The proposed method held higher selectivity than other CL methods and was applied to determination of uric acid in human serum. The possible CL reaction mechanism was also discussed briefly. PMID:20188949

  19. Elevated first-trimester uric acid concentrations are associated with the development of gestational diabetes

    PubMed Central

    LAUGHON, S. Katherine; CATOVR, Janet; PROVINS, Traci; ROBERTS, James M.; GANDLEY, Robin E.

    2009-01-01

    Objective: To demonstrate that elevated first trimester uric acid is associated with development of gestational diabetes mellitus (GDM). Study Design: Uric acid was measured in 1570 plasma samples collected at mean gestational age of 8.9 ± 2.5 weeks. The primary outcome was GDM, diagnosed by three hour glucose tolerance test using Carpenter and Coustan criteria or by a one hour value of ? 200 mg/dl. Logistic regression was performed, adjusting for relevant covariates. Results: Almost half (46.6%) of the women with GDM had first trimester uric acid concentrations in the highest quartile (>3.57-8.30 mg/dl). Women with uric acid in the highest quartile had a 3.25-fold increased risk (95%CI: 1.35, 7.83) of developing GDM after adjustment for BMI and age. This effect was concentration dependent as risk increased with increasing uric acid quartiles (p=0.003). Conclusion: First trimester hyperuricemia is associated with an increased risk of developing GDM, independent of BMI. PMID:19788971

  20. Detection of Interstellar Urea with Carma

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

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

    PubMed Central

    2013-01-01

    Objectives To assess the associations between both uric acid levels and hyperuricaemia, with ischaemic heart disease and blood pressure, and to explore the potentially confounding role of body mass index. Design Mendelian randomisation analysis, using variation at specific genes (SLC2A9 (rs7442295) as an instrument for uric acid; and FTO (rs9939609), MC4R (rs17782313), and TMEM18 (rs6548238) for body mass index). Setting Two large, prospective cohort studies in Denmark. Participants We measured levels of uric acid and related covariables in 58?072 participants from the Copenhagen General Population Study and 10?602 from the Copenhagen City Heart Study, comprising 4890 and 2282 cases of ischaemic heart disease, respectively. Main outcome Blood pressure and prospectively assessed ischaemic heart disease. Results Estimates confirmed known observational associations between plasma uric acid and hyperuricaemia with risk of ischaemic heart disease and diastolic and systolic blood pressure. However, when using genotypic instruments for uric acid and hyperuricaemia, we saw no evidence for causal associations between uric acid, ischaemic heart disease, and blood pressure. We used genetic instruments to investigate body mass index as a potentially confounding factor in observational associations, and saw a causal effect on uric acid levels. Every four unit increase of body mass index saw a rise in uric acid of 0.03 mmol/L (95% confidence interval 0.02 to 0.04), and an increase in risk of hyperuricaemia of 7.5% (3.9% to 11.1%). Conclusion By contrast with observational findings, there is no strong evidence for causal associations between uric acid and ischaemic heart disease or blood pressure. However, evidence supports a causal effect between body mass index and uric acid level and hyperuricaemia. This finding strongly suggests body mass index as a confounder in observational associations, and suggests a role for elevated body mass index or obesity in the development of uric acid related conditions. PMID:23869090

  2. Reversible denaturation of cyclosporin synthetase by urea

    Microsoft Academic Search

    Joachim Dittmann; François Vaillant; Horst Kleinkauf; Alfons Lawen

    1996-01-01

    The reversible denaturation of the multifunctional polypeptide, cyclosporin synthetase, by urea was analyzed. It is possible to discriminate between at least two stages of enzyme denaturation. While at low urea concentration (up to 0.8 M) cyclosporin A formation is inhibited, synthesis of the diketopiperazine cyclo-(d-alanyl-N-methylleucyl), a molecule representing a partial sequence of cyclosporin A is still detectable. At higher concentrations

  3. The fractionation of lanolin with urea

    Microsoft Academic Search

    Abner Eisner; Wilfred R. Noble; John T. Scanlan

    1959-01-01

    Summary  A fractionation of lanolin was effected by contacting lanolin with urea in the presence of methyl alcohol. About 6–8% of the\\u000a lanolin formed a urea adduct which, upon decomposition, yielded a hard, nontacky wax fraction. In addition to the wax fraction,\\u000a a fluid fraction and a sticky semi-solid were also obtained. The latter two fractions were obtained by the solvent

  4. Nanostructured zinc oxide film for urea sensor

    Microsoft Academic Search

    Azahar Ali; Anees A. Ansari; Ajeet Kaushik; Pratima R. Solanki; A. Barik; M. K. Pandey; B. D. Malhotra

    2009-01-01

    Nanostructured zinc oxide (Nano-ZnO) film has been electrochemically deposited onto indium-tin-oxide (ITO) coated glass plate to co-immobilized urease (Urs) and glutamate dehydrogenase (GLDH) for urea detection. The observed reflection planes corresponding to wurtzite ZnO nanoparticles (~25nm) in XRD diffraction pattern and UV-visible absorption band at 338nm reveal the formation of Nano-ZnO. Urs-GLDH\\/Nano-ZnO\\/ITO bioelectrode shows high sensitivity for urea detection within

  5. Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas.

    PubMed

    Anderson, W Gary; Good, Jonathan P; Pillans, Richard D; Hazon, Neil; Franklin, Craig E

    2005-10-01

    Plasma urea levels and hepatic urea production in the euryhaline bull shark, Carcharhinus leucas, acclimated to freshwater and seawater environments were measured. It was found that plasma urea concentration increased with salinity and that this increase was, in part, the result of a significant increase in hepatic production of urea. This study provides direct evidence that hepatic production of urea plays an important role in the osmoregulatory strategy of C. leucas. PMID:16161010

  6. Uric acid levels predict survival in men with amyotrophic lateral sclerosis.

    PubMed

    Paganoni, Sabrina; Zhang, May; Quiroz Zárate, Alejandro; Jaffa, Matthew; Yu, Hong; Cudkowicz, Merit E; Wills, Anne-Marie

    2012-09-01

    Elevated uric acid levels have recently been found to be associated with slower disease progression in Parkinson's disease, Huntington's disease, multiple system atrophy, and mild cognitive impairment. The aim of this study is to determine whether serum uric acid levels predict survival in amyotrophic lateral sclerosis (ALS). A total of 251 people with ALS enrolled in two multicenter clinical trials were included in our analysis. The main outcome measure was survival time, which was calculated as time to death, tracheostomy, or permanent assistive ventilation, with any event considered a survival endpoint. Cox proportional hazards models were used to estimate the hazard ratio (HR) of reaching a survival endpoint according to baseline uric acid levels after adjusting for markers of disease severity (FVC, total ALSFRS-R score, time since symptom onset, diagnostic delay, BMI, bulbar vs. spinal onset, age, and riluzole use). There was a dose-dependent survival advantage in men, but not women, with higher baseline uric acid levels (logrank test: p = 0.018 for men, p = 0.81 for women). There was a 39% reduction in risk of death during the study for men with each 1 mg/dl increase in uric acid levels (adjusted HR: 0.61, 95% CI 0.39-0.96, p = 0.03). This is the first study to demonstrate that serum uric acid is associated with prolonged survival in ALS, after adjusting for markers of disease severity. Similar to previous reports in Parkinson's disease, this association was seen in male subjects only. PMID:22323210

  7. Association of three genetic loci with uric acid concentration and risk of gout: a genome-wide association study

    Microsoft Academic Search

    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

    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

  8. Disposition and uric acid lowering effect of oxipurinol: comparison of different oxipurinol formulations and allopurinol in healthy individuals

    Microsoft Academic Search

    I. Walter-Sack; J. X. de Vries; C. Kutschker; A. Ittensohn; A. Voss

    1995-01-01

    We have investigated the disposition and plasma uric acid lowering effect of oxipurinol in ten healthy individuals following oral administration of three different formulations of oxipurinol and of allopurinol in equimolar doses. The reduction of plasma uric acid was clearcut up to 48 h. As estimated from plasma AUC0-8, Cmax, tmax, tlag, and urinary drug excretion, a conventional rapid release

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

    Microsoft Academic Search

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

    1994-01-01

    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

  10. The determination of ascorbic acid and uric acid in human seminal plasma using an HPLC with UV detection

    Microsoft Academic Search

    Roman Kan?ár; Petra Drábková; Radek Hampl

    2011-01-01

    Oxidative stress has been proposed as one of the potential causes for infertility in men. Ascorbic acid and uric acid play important role in protection of spermatozoa against free radicals. A method for the simultaneous determination of ascorbic acid and uric acid in human seminal plasma using HPLC with UV detection and investigation their clinical significance as antioxidants protecting male

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

    Microsoft Academic Search

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

    1981-01-01

    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

  12. Increased fluid intake and adequate dietary modification may be enough for the successful treatment of uric acid stone.

    PubMed

    Chae, Ji Yun; Kim, Jong Wook; Kim, Jin Wook; Yoon, Cheol Yong; Park, Hong Seok; Moon, Du Geon; Oh, Mi Mi

    2013-04-01

    Uric acid stones are the most readily dissolvable of all types of urinary stones. The present paper describes two patients with uric acid stones in kidney and ureter, whom we have treated successfully only by a combination of increased fluid intake and adequate dietary modification. PMID:23503881

  13. Preliminary Use of Uric Acid as a Biomarker for Wading Birds on Everglades Tree Islands, Florida, United States

    USGS Publications Warehouse

    Bates, Anne L.; Orem, William H.; Newman, Susan; Gawlik, Dale E.; Lerch, Harry E.; Corum, Margo D.; Van Winkle, Monica

    2010-01-01

    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.

  14. An excess electron bound to urea. III. The urea dimer as an electron trap Piotr Skurski

    E-print Network

    Simons, Jack

    Simonsa) Henry Eyring Center for Theoretical Chemistry, Department of Chemistry, University of Utah, SaltAn excess electron bound to urea. III. The urea dimer as an electron trap Piotr Skurski Henry Eyring Center for Theoretical Chemistry Department of Chemistry, University of Utah, Salt Lake City, Utah

  15. 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]...

  16. A Method for Estimating Uptake and Produdion Rates for Urea in Seawater using Urea and

    E-print Network

    Hansell, Dennis

    estimatinguptakeand productionrates for urea in seawater using [j4"N]ureaand ["Clurea. Can. J.Fish. Aquat. Sci. 46: 19. Several models have been developed that attempt to describe the pathways sf the nitrogennutrientsmost have not been horougMy tested. Urea is an endproduct of hekrotrophic nitrogen metabolism thatcanbe

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

    Microsoft Academic Search

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

    2006-01-01

    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

  18. Uric Acid and Pentraxin-3 Levels Are Independently Associated with Coronary Artery Disease Risk in Patients with Stage 2 and 3 Kidney Disease

    Microsoft Academic Search

    Mehmet Kanbay; Mustafa Ikizek; Yalcin Solak; Yusuf Selcoki; Sema Uysal; Ferah Armutcu; Beyhan Eryonucu; Adrian Covic; Richard J. Johnson

    2011-01-01

    Background and Objectives: Cardiovascular disease is prevalent in chronic kidney disease (CKD). Uric acid is increased in subjects with CKD and has been linked with cardiovascular mortality in this population. However, no study has evaluated the relationship of uric acid with angiographically proven coronary artery disease (CAD) in this population. We therefore investigated the link between serum uric acid (SUA)

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

    PubMed

    Recavarren, M I; Milano, G D

    2014-12-01

    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

  20. 69 FR 58957 - Solid Urea From Belarus, Estonia, Lithuania, Romania, Russia, Tajikistan, Turkmenistan, Ukraine...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2004-10-01

    ...Urea From Belarus, Estonia, Lithuania, Romania, Russia, Tajikistan, Turkmenistan...urea from Belarus, Estonia, Lithuania, Romania, Russia, Tajikistan, Turkmenistan...urea from Belarus, Estonia, Lithuania, Romania, Russia, Tajikistan,...

  1. Creatinine and myoglobin are poor predictors of anaerobic threshold in colorectal cancer and health

    PubMed Central

    Nyasavajjala, Sitaramachandra M; Phillips, Beth E; Lund, Jon N; Williams, John P

    2015-01-01

    Aims Myoglobin is a haem protein produced in skeletal muscles. Serum concentrations of myoglobin have been proposed as a surrogate marker of muscle mass and function in both cachectic cancer patients and healthy non-cancer individuals. Creatinine, a metabolite of creatine phosphate, an energy store found in skeletal muscle, is produced at a constant rate from skeletal muscle. Urinary and plasma creatinine have been used in clinical practice as indicators of skeletal muscle mass in health and disease. Our study aimed to test the hypothesis that plasma myoglobin and creatinine concentration could accurately predict skeletal muscle mass and aerobic capacity in colorectal cancer (CRC) patients and matched healthy controls and thereby an indicative of aerobic performance. Methods We recruited 47 patients with CRC and matching number of healthy volunteers for this study. All participants had their body composition measured by dual-energy X-ray absorptiometry scan, aerobic capacity measured to anaerobic threshold (AT) by cardiopulmonary exercise testing and filled in objective questionnaires to assess the qualitative functions. This study was carried out in accordance with the Declaration of Helsinki, after approval by the local National Health Service (NHS) Research Ethics Committee. Results Age-matched groups had similar serum myoglobin and creatinine concentrations in spite of differences in their aerobic capacity. AT was significantly lower in the CRC group compared with matched controls (1.18?±?0.44 vs. 1.41?±?0.71?L/min; P?creatinine had poor correlation with LMM and AT. Conclusions Serum myoglobin is a poor predictor of muscle mass, and serum myoglobin and creatinine concentrations do not predict aerobic performance in CRC patients or healthy matched controls.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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.

  3. Pharmacokinetics, pharmacodynamics, and safety of lesinurad, a selective uric acid reabsorption inhibitor, in healthy adult males

    PubMed Central

    Shen, Zancong; Rowlings, Colin; Kerr, Brad; Hingorani, Vijay; Manhard, Kimberly; Quart, Barry; Yeh, Li-Tain; Storgard, Chris

    2015-01-01

    Lesinurad is a selective uric acid reabsorption inhibitor under investigation for the treatment of gout. Single and multiple ascending dose studies were conducted to evaluate pharmacokinetics, pharmacodynamics, and safety of lesinurad in healthy males. Lesinurad was administered as an oral solution between 5 mg and 600 mg (single ascending dose; N=34) and as an oral solution or immediate-release capsules once daily (qday) between 100 mg and 400 mg for 10 days under fasted or fed condition (multiple ascending dose; N=32). Following single doses of lesinurad solution, absorption was rapid and exposure (maximum observed plasma concentration and area under the plasma concentration–time curve) increased in a dose-proportional manner. Following multiple qday doses, there was no apparent accumulation of lesinurad. Urinary excretion of unchanged lesinurad was generally between 30% and 40% of dose. Increases in urinary excretion of uric acid and reductions in serum uric acid correlated with dose. Following 400 mg qday dosing, serum uric acid reduction was 35% at 24 hours post-dose, supporting qday dosing. A relative bioavailability study in healthy males (N=8) indicated a nearly identical pharmacokinetic profile following dosing of tablets or capsules. Lesinurad was generally safe and well tolerated. PMID:26170627

  4. Adaptation to multiday ozone exposure is associated with a sustained increase of bronchoalveolar uric acid.

    PubMed

    Kirschvink, Nathalie; Fiévez, Laurence; Bureau, Fabrice; Degand, Guy; Maghuin-Rogister, Guy; Smith, Nicola; Art, Tatiana; Lekeux, Pierre

    2002-01-01

    The phenomenon of ozone tolerance is described, but the underlying mechanisms remain unknown. We tested whether adaptation to multiday ozone exposure was related to an upregulated pulmonary antioxidant defence. Six calves were exposed to 0.75 ppm ozone, 12 h day(-1) for seven consecutive days. Pulmonary function tests and bronchoalveolar lavage (BAL) were performed before, after the first (D1), third (D3) and seventh (D7) exposure. Differential cell count, total proteins, 8-epi-PGF2alpha, glutathione and uric acid were determined in BAL. Dynamic lung compliance and arterial oxygen tension were significantly decreased and lung oedema impaired pulmonary function on D1. By repeating ozone exposures, progressive functional adaptation occurred. Ozone induced a significant increase of BAL neutrophil percentage on D1. On D3 and D7, neutrophil percentage was progressively decreased, but remained significantly elevated. BAL total proteins were significantly increased on D1 and decreased progressively until D7. 8-Epi-PGF2alpha was significantly increased on D1 and was returned to baseline on D3 and D7, whilst glutathione significantly increased on D3 and returned to baseline on D7. Uric acid was increased ten-fold on D1. On D3, uric acid was increased six-fold and was persistently elevated at D7. This study suggests that ozone adaptation of functional and inflammatory variables is accompanied with sustained BAL uric acid elevation. PMID:11999700

  5. Simultaneous electrochemical determination of xanthine and uric acid at a nanoparticle film electrode

    Microsoft Academic Search

    Yanyi Sun; Junjie Fei; Kangbing Wu; Shengshui Hu

    2003-01-01

    A sensitive electrochemical method was developed for simultaneous determination of uric acid (UA) and xanthine (XA) at a glassy carbon electrode modified with multi-wall carbon nanotubes (MWNTs) film. The oxidation peak currents of UA and XA were increased at the MWNTs film electrode significantly. The experimental parameters, which influence the peak currents of UA and XA, such as the amount

  6. Uric acid accumulation in an Arabidopsis urate oxidase mutant impairs seedling establishment by blocking peroxisome maintenance.

    PubMed

    Hauck, Oliver K; Scharnberg, Jana; Escobar, Nieves Medina; Wanner, Gerhard; Giavalisco, Patrick; Witte, Claus-Peter

    2014-07-01

    Purine nucleotides can be fully catabolized by plants to recycle nutrients. We have isolated a urate oxidase (uox) mutant of Arabidopsis thaliana that accumulates uric acid in all tissues, especially in the developing embryo. The mutant displays a reduced germination rate and is unable to establish autotrophic growth due to severe inhibition of cotyledon development and nutrient mobilization from the lipid reserves in the cotyledons. The uox mutant phenotype is suppressed in a xanthine dehydrogenase (xdh) uox double mutant, demonstrating that the underlying cause is not the defective purine base catabolism, or the lack of UOX per se, but the elevated uric acid concentration in the embryo. Remarkably, xanthine accumulates to similar levels in the xdh mutant without toxicity. This is paralleled in humans, where hyperuricemia is associated with many diseases whereas xanthinuria is asymptomatic. Searching for the molecular cause of uric acid toxicity, we discovered a local defect of peroxisomes (glyoxysomes) mostly confined to the cotyledons of the mature embryos, which resulted in the accumulation of free fatty acids in dry seeds. The peroxisomal defect explains the developmental phenotypes of the uox mutant, drawing a novel link between uric acid and peroxisome function, which may be relevant beyond plants. PMID:25052714

  7. Serum uric acid and its association with metabolic syndrome and carotid atherosclerosis in obese children

    Microsoft Academic Search

    Lucia Pacifico; Vito Cantisani; Caterina Anania; Elisabetta Bonaiuto; Francesco Martino; Roberto Pascone; Claudio Chiesa

    2008-01-01

    Objective: The association between hyperuricemia, metabolic syndrome (MS), and atherosclerotic vascular disease has been reported in adults, but very little is known about this association in children. The aims of our study were to ascertain the correlates of uric acid (UA) in a sample of obese children, and to investigate whether UA is associated with carotid intima-media thickness (IMT) independently

  8. Discrete analysis of serum uric acid with immobilized uricase and peroxidase.

    PubMed

    Bhargava, A K; Lal, H; Pundir, C S

    1999-05-13

    Commercially available uricase and peroxidase have been immobilized onto alkylamine glass and arylamine glass beads respectively. A discrete method has been developed to determine uric acid in serum using immobilized uricase and peroxidase. The method is based on generation of H2O2 from serum uric acid by immobilized uricase and its measurement by a colour reaction catalyzed by immobilized peroxidase. The minimum detection limit of the method was 8 microg/0.1 ml sample. The mean analytical recovery of added uric acid in serum was 87.5%. The within and between assay coefficient of variation (C.V.) were <6.58% and <10.77% respectively. The serum uric acid in apparently healthy adults and persons suffering from different disease was found to be 25-55 microg/ml, 32+/-2.25 (range, mean+/-S.D.) and 55-200 microg/ml; 52+/-6.4 (range, mean+/-S.D.) respectively by our method. A good correlation (r = 0.8170) was obtained between the serum urate values by this method and with those obtained by commercial Enzo-kit method. PMID:10392568

  9. A Synthetic Uric Acid Analog Accelerates Cutaneous Wound Healing in Mice

    Microsoft Academic Search

    Srinivasulu Chigurupati; Mohamed R. Mughal; Sic L. Chan; Thiruma V. Arumugam; Akanksha Baharani; Sung-Chun Tang; Qian-Sheng Yu; Harold W. Holloway; Ross Wheeler; Suresh Poosala; Nigel H. Greig; Mark P. Mattson; Joanna Mary Bridger

    2010-01-01

    Wound healing is a complex process involving intrinsic dermal and epidermal cells, and infiltrating macrophages and leukocytes. Excessive oxidative stress and associated inflammatory processes can impair wound healing, and antioxidants have been reported to improve wound healing in animal models and human subjects. Uric acid (UA) is an efficient free radical scavenger, but has a very low solubility and poor

  10. Serum uric acid is associated with microvascular function in hypertensive individuals

    Microsoft Academic Search

    T de A Coutinho; S T Turner; I J Kullo

    2007-01-01

    We investigated the relationship of serum uric acid (UA) with resting forearm blood flow (FBF), reactive hyperaemia (RH) and flow-mediated dilation (FMD) of the brachial artery in hypertensive adults (n=506, mean age 62 years, 59% women). UA was measured by a colorimetric method. FBF, RH and FMD were measured by brachial artery ultrasound. Regression analyses were used to assess whether

  11. Uric acid is a strong independent predictor of renal dysfunction in patients with rheumatoid arthritis

    Microsoft Academic Search

    Dimitrios Daoussis; Vasileios Panoulas; Tracey Toms; Holly John; Ioannis Antonopoulos; Peter Nightingale; Karen MJ Douglas; Rainer Klocke; George D Kitas

    2009-01-01

    INTRODUCTION: Recent evidence suggests that uric acid (UA), regardless of crystal deposition, may play a direct pathogenic role in renal disease. We have shown that UA is an independent predictor of hypertension and cardiovascular disease (CVD), and that CVD risk factors associate with renal dysfunction, in patients with rheumatoid arthritis (RA). In this study we investigated whether UA associates with

  12. The Value of Serum Uric Acid as a Mortality Prediction in Critically Ill Children

    PubMed Central

    Hooman, Nakysa; Mehrazma, Mitra; Nakhaii, Shahrbanoo; Otukesh, Hasan; Moradi-Lakeh, Maziar; Dianati-Maleki, Neda; Ehteshami-Afshar, Arash

    2010-01-01

    Objective The role of initial serum uric acid on admission in critically ill patients is controversial; we presumed that uric acid level can predict the mortality of the admitted patients to intensive care unit as a simple test. Methods Totally, 220 consecutively admitted children (96 girls, 124 boys) with mean age 3.5 years, who were at least 24 hours in pediatric intensive care unit (PICU), were enrolled in a prospective cohort study during January 2006 to December 2007. The subsequent PICU admission in the same hospitalization, those who were discharged from the hospital and then re-admitted to the PICU during the observation period, and the patients with chronic renal failure were excluded. Serum uric acid level was measured during the first day of PICU admission. Death or transfer from PICU was considered as final outcome. The statistical analysis was done by using linear regression analysis, ROC curve, Student t-test, and Chi- square. P value less than 0.05 was considered significant. Findings From 44 patients who had serum uric acid level more than 8 mg/dl, 17 cases died showing with a higher relative risk of 1.88, higher mortality (P<0.05). The relative risk of death in patients who had serum uric acid >8 mg/dl and needed vasopressor was 1.04, and in those under mechanical ventilation 1.33. In patients who scored pediatric risk of mortality of >38 it was 1.4, and in septic cases 4 (P<0.05). Stepwise linear regression analysis showed that mainly the need for mechanical ventilation (P=0.001) and vasopressor had statistically significant correlation with the poor outcome (P=0.001). Conclusion Uric acid level during the first day of intensive critical care admission is not an independent risk of mortality in PICU. Need for mechanical ventilation or inotropic agents was associated with poor outcome and only higher uric acid level in sepsis played an additive risk factor role. PMID:23056724

  13. Plasma uric acid level indicates tubular interstitial leisions at early stage of IgA nephropathy

    PubMed Central

    2014-01-01

    Background Hyperuricemia appeared to be a common symptom in IgA nephropathy (IgAN), even in those with normal eGFR. IgAN was characterized by variation of pathological features, especially variable tubulointerstitial lesions. Since tubular reabsorption and excretion appeared to be more important in determination of plasma uric acid levels in persons without obvious decrease of glomerular filtration rate, we took advantage of our IgAN cohort to investigate whether plasma uric acid level associated with tubular interstitial lesions, and could be considered as a maker for tubular interstitial lesions, especially at early stage with normal eGFR. Methods 623 IgAN patients were involved in the present study. Morphological changes were evaluated with Oxford classification scoring system as well as Beijing classification system of IgAN. Statistical analysis was done with SPSS 13.0. Results We found that plasma uric acid level associated with percentage of interstitial fibrosis/tubular atrophy. Higher plasma uric acid levels indicated higher tubulointerstitial scores, either with Oxford system (P?=?0.012) or with Beijing classification system (P?=?4.8*10-4) in the whole cohort. We also found that in the subgroup of 258 IgAN cases with normal baseline eGFR (eGFR?>?=90 ml/min/1.73 M2), higher plasma uric acid associated with more severe tubulointerstitial lesions with Beijing scoring system (P?=?3.4*10-5). The risk of having more than 10% tubulointerstitial lesions in patients with hyperuricemia increased 58% compared with normal uric acid level. In subgroup with normal eGFR, only hyperuricemia predicted tubulointerstitial leisions, and the risk of having more tubulointerstitial changes increased 100%. Among these patients, hyperuricemia was associated with more tubulointerstitial lesions with a specificity of 60.3%. Specificity increased to 65% among those patients with eGFR?>?=90 ml/min/1.73 m2. Conclusions Plasma uric acid levels indicate tubular interstitial lesions in IgAN and hyperuricemia may be considered as a marker for tubulointerstitial lesions. PMID:24423013

  14. On-line near-infrared spectrometer to monitor urea removal in real time during hemodialysis.

    PubMed

    Cho, David S; Olesberg, Jonathon T; Flanigan, Michael J; Arnold, Mark A

    2008-08-01

    The ex vivo removal of urea during hemodialysis treatments is monitored in real time with a noninvasive near-infrared spectrometer. The spectrometer uses a temperature-controlled acousto optical tunable filter (AOFT) in conjunction with a thermoelectrically cooled extended wavelength InGaAs detector to provide spectra with a 20 cm(-1) resolution over the combination region (4000-5000 cm(-1)) of the near-infrared spectrum. Spectra are signal averaged over 15 seconds to provide root mean square noise levels of 24 micro-absorbance units for 100% lines generated over the 4600-4500 cm(-1) spectral range. Combination spectra of the spent dialysate stream are collected in real-time as a portion of this stream passes through a sample holder constructed from a 1.1 mm inner diameter tube of Teflon. Real-time spectra are collected during 17 individual dialysis sessions over a period of 10 days. Reference samples were extracted periodically during each session to generate 87 unique samples with corresponding reference concentrations for urea, glucose, lactate, and creatinine. A series of calibration models are generated for urea by using the partial least squares (PLS) algorithm and each model is optimized in terms of number of factors and spectral range. The best calibration model gives a standard error of prediction (SEP) of 0.30 mM based on a random splitting of spectra generated from all 87 reference samples collected across the 17 dialysis sessions. PLS models were also developed by using spectra collected in early sessions to predict urea concentrations from spectra collected in subsequent sessions. SEP values for these prospective models range from 0.37 mM to 0.52 mM. Although higher than when spectra are pooled from all 17 sessions, these prospective SEP values are acceptable for monitoring the hemodialysis process. Selectivity for urea is demonstrated and the selectivity properties of the PLS calibration models are characterized with a pure component selectivity analysis. PMID:18702859

  15. The incidence of urea cycle disorders.

    PubMed

    Summar, Marshall L; Koelker, Stefan; Freedenberg, Debra; Le Mons, Cynthia; Haberle, Johannes; Lee, Hye-Seung; Kirmse, Brian

    2013-01-01

    A key question for urea cycle disorders is their incidence. In the United States two UCDs, argininosuccinic synthetase and lyase deficiency, are currently detected by newborn screening. We used newborn screening data on over 6million births and data from the large US and European longitudinal registries to determine how common these conditions are. The incidence for the United States is predicted to be 1 urea cycle disorder patient for every 35,000 births presenting about 113 new patients per year across all age groups. PMID:23972786

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

    PubMed

    Costa, A; Igualá, I; Bedini, J; Quintó, L; Conget, I

    2002-03-01

    High uric acid concentration is a common finding in subjects with risk factors for cardiovascular disease (CVD), including some characteristics of the metabolic syndrome. However, its exact role in this setting and in the progression to type 2 diabetes mellitus (DM) is not well understood and could be affected by confounding factors such as hypertriglyceridemia. Our study aimed to establish the relationship between uric acid (avoiding the interference of high triglyceride levels), insulin sensitivity, and components of the metabolic syndrome in a group of subjects at high risk of developing DM. Among 201 subjects included in the study, 111 (55.2%) showed an abnormal oral glucose tolerance and uric acid levels higher than those measured in subjects with normal glucose tolerance. Body mass index (BMI), triglycerides, diastolic blood pressure (DBP), and 2-hour glycemia in the oral glucose tolerance test (OGTT) contributed independently to uric acid concentration (R2 =.59). However, uric acid did not affect either insulin sensitivity or glucose tolerance. The recovery tests revealed that a triglyceride concentration > or = 3 mmol/L interfered with the measurement of uric acid level when a colorimetric method was used, but not when a dry-chemistry method was used. In conclusion, uric acid concentration is higher in subjects at high risk of DM with abnormal glucose tolerance and is independently determined by various components of the metabolic syndrome. PMID:11887176

  17. Arxula adeninivorans recombinant urate oxidase and its application in the production of food with low uric acid content.

    PubMed

    Trautwein-Schult, Anke; Jankowska, Dagmara; Cordes, Arno; Hoferichter, Petra; Klein, Christina; Matros, Andrea; Mock, Hans-Peter; Baronian, Keith; Bode, Rüdiger; Kunze, Gotthard

    2013-01-01

    Hyperuricemia and its symptoms are becoming increasingly common worldwide. Elevated serum uric acid levels are caused by increased uric acid synthesis from food constituents and reduced renal excretion. Treatment in most cases involves reducing alcohol intake and consumption of meat and fish or treatment with pharmaceuticals. Another approach could be to reduce uric acid level in food, either during production or consumption. This work reports the production of recombinant urate oxidase by Arxula adeninivorans and its application to reduce uric acid in a food product. The A. adeninivorans urate oxidase amino acid sequence was found to be similar to urate oxidases from other fungi (61-65% identity). In media supplemented with adenine, hypoxanthine or uric acid, induction of the urate oxidase (AUOX) gene and intracellular accumulation of urate oxidase (Auoxp) was observed. The enzyme characteristics were analyzed from isolates of the wild-type strain A. adeninivorans LS3, as well as from those of transgenic strains expressing the AUOX gene under control of the strong constitutive TEF1 promoter or the inducible AYNI1 promoter. The enzyme showed high substrate specificity for uric acid, a broad temperature and pH range, high thermostability and the ability to reduce uric acid content in food. PMID:24022585

  18. Inhibition of UV-induced uric acid production using allopurinol prevents suppression of the contact hypersensitivity response.

    PubMed

    Leighton, Sarah; Kok, Lai-Fong; Halliday, Gary M; Byrne, Scott N

    2013-03-01

    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

  19. The impact of dietary protein intake on urinary creatinine excretion in a healthy pediatric population

    Microsoft Academic Search

    Annette Neubert; Thomas Remer

    1998-01-01

    Objective: The aim of the study was to investigate the effect of daily protein intake on urinary creatinine (CR) excretion in healthy children. Methods: In a cross-sectional study, 24-hour urinary CR excretion rates were measured in 350 children aged 4 to 13 years. Body composition was assessed according to anthropometric measurements, and intake of protein was estimated from dietary records.

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

    PubMed Central

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

    2015-01-01

    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

  1. Exogenous thyrotropin improves renal function in euthyroid patients, while serum creatinine levels are increased in hypothyroidism

    PubMed Central

    Duranton, Flore; Lacoste, Anouchka; Faurous, Patrick; Deshayes, Emmanuel; Ribstein, Jean; Avignon, Antoine; Mourad, Georges; Argilés, Ŕngel

    2013-01-01

    Background There is evidence showing that the hypothyroid state results in increased serum creatinine levels. However, whether this is only due to the peripheral thyroid hormones or if thyroid-stimulating hormone (TSH) is also involved is not known. Methods Serum creatinine levels and estimated glomerular filtration rate (eGFR) were assessed in thyroidectomized patients with varying thyroid hormones and TSH levels. Blood samples from Group 1 (21 patients) were obtained 1 month after complete thyroidectomy, while under a hypothyroid state (t1) and a sufficient time after thyroid hormones initiation (euthyroid state, t2). Group 2 (20 euthyroid patients) were sampled after recombinant human thyrotropin injections (rhTSH, t1) and later after rhTSH extinction (t2). Results In Group 1, serum creatinine levels decreased after correction of hypothyroidism (85.3 ± 4.3 versus 78.0 ± 3.9 µmol/L; P = 0.04). In Group 2, serum creatinine levels increased after rhTSH withdrawal (70.6 ± 5.7 µmol/L versus 76.5 ± 5.8 µmol/L; P = 0.007). Between t1 and t2, eGFR varied accordingly [Group 1, 71.7 ± 3.5 versus 81.2 ± 4.5 mL/min/1.73 m˛ (P = 0.02); Group 2, 97.7 ± 7.4 versus 87.5 ± 5.9 (P = 0.007)]. The changes in TSH and eGFR following supplementation with thyroxine were significantly correlated (r = ?0.6, P = 0.0041). Conclusions Iatrogenic hypothyroidism significantly increases serum creatinine and reversibly impairs eGFR, while treatment with rhTSH enhances renal function in euthyroid patients, supporting the existence of an influence of TSH level on renal function. The mechanisms by which peripheral thyroid hormones and TSH influence GFR need to be identified in physiology-orientated studies.

  2. Chronic administration of troxerutin protects mouse kidney against d-galactose-induced oxidative DNA damage

    Microsoft Academic Search

    Chan-Min Liu; Jie-Qiong Ma; Yao Lou

    2010-01-01

    Troxerutin, a natural bioflavonoid, has been reported to have many benefits and medicinal properties. In this study, we evaluated the protective effect of troxerutin against d-gal-induced oxidative DNA damage in mouse kidney, and explored the potential mechanism of its action. Our data showed that troxerutin significantly decreased levels of urea, uric acid and creatinine in serum and the renal histological

  3. APPLICATION OF MILK UREA NITROGEN VALUES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Statistical analyses using both linear and multi-component regression and mixed effects models have been applied to a number of databases relating milk urea nitrogen (MUN) to factors important for N utilization in lactating dairy cows. Concentrations of MUN are highly correlated to BUN, which is a s...

  4. Aldehyde-containing urea-absorbing polysaccharides

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    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.

  5. Continuous Crystallization of Urea-Water Mixture

    NASA Astrophysics Data System (ADS)

    Hokamura, Taku; Ohkubo, Hidetoshi; Watanabe, Satoshi; Seki, Mitsuo; Murakoshi, Hiromichi

    Ice slurries have been used as environmentally-friendly secondary refrigerants. In addition to such ice slurries, aqueous solutions in slurry-state have also been put to practical use at temperatures below 0 oC. Urea-water mixture is a multi-component substance that has a eutectic point. If we can form a two-phase fluid substance by the liquid-solid phases at the eutectic point, it can be used as a fluid latent heat storage material, which will maintain the secondary refrigerant in a heat exchanger at constant temperature. In the present study, we propose a urea-water mixture as a novel functional thermal fluid that can be used as a fluid latent heat material. To demonstrate its feasibility, we first measured the latent heat and density of a urea-water mixture, and then used a counter-flow double tube heat exchanger to produce a liquid-solid two-phase flow of the urea-water mixture. This work demonstrates that it is possible to make a fluid latent heat storage material continuously from an aqueous solution at the eutectic point by flowing it through a double tube heat exchanger equipped with a stirrer.

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

    E-print Network

    Park, Yong Hun

    2004-09-30

    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 ...

  7. 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. ...

  8. Homogeneous precipitation of alumina precursors via enzymatic decomposition of urea

    Microsoft Academic Search

    Hidero Unuma; Shinichi Kato; Toshitaka Ota; Minoru Takahashi

    1998-01-01

    A modified homogeneous precipitation technique involving enzymatic decomposition of urea was proposed and was applied to the synthesis of alumina precursors. Spherical aluminum hydroxide aggregates were prepared at 298 K from aqueous solutions containing aluminum sulfate, urea and urease. In contrast to the conventional technique involving thermally induced decomposition of urea, the resultant aggregates were amorphous with no trace of

  9. Hemodialysis urea rebound: The effect of increasing dialysis efficiency

    Microsoft Academic Search

    David M. Spiegel; Penny L. Baker; Susan Babcock; Robert Contiguglia; Melvyn Klein

    1995-01-01

    Urea rebound has been documented to occur after hemodialysis, but the magnitude and causes are not clearly defined. In this study we evaluated the effect of high-flux hemodialysis on urea rebound and Kt\\/V. Blood urea nitrogen samples were obtained before, immediately after, and 30 minutes after hemodialysis in 49 patients. Rebound was evaluated with respect to dialysis efficiency, dialysis treatment

  10. Characterization of urea transport in Bufo arenarum oocytes.

    PubMed

    Silberstein, Claudia; Zotta, Elsa; Ripoche, Pierre; Ibarra, Cristina

    2003-07-01

    Xenopus laevis oocytes have been extensively used for expression cloning, structure/function relationships, and regulation analysis of transporter proteins. Urea transporters have been expressed in Xenopus oocytes and their properties have been described. In order to establish an alternative system in which urea transporters could be efficiently expressed and studied, we determined the urea transport properties of ovarian oocytes from Bufo arenarum, a toad species common in Argentina. Bufo oocytes presented a high urea permeability of 22.3 x 10(-6) cm/s, which was significantly inhibited by the incubation with phloretin. The urea uptake in these oocytes was also inhibited by mercurial reagents, and high-affinity urea analogues. The urea uptake was not sodium dependent. The activation energy was 3.2 Kcal/mol, suggesting that urea movement across membrane oocytes may be through a facilitated urea transporter. In contrast, Bufo oocytes showed a low permeability for mannitol and glycerol. From these results, we propose that one or several specific urea transporters are present in ovarian oocytes from Bufo arenarum. Therefore, these oocytes cannot be used in expression studies of foreign urea transporters. The importance of Bufo urea transporter is not known but could be implicated in osmotic regulation during the laying of eggs in water. PMID:12840834

  11. Synergetic Effects of Nanoporous Support and Urea on Enzyme Activity

    SciTech Connect

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

    2007-02-01

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

  12. Ammonia volatilization losses from prilled urea, urea supergranules (USG) and coated USG in rice fields

    Microsoft Academic Search

    K. Sudhakara; R. Prasad

    1986-01-01

    Summary  About 8.4 per cent of applied nitrogen was lost as ammonia during a week after application when prilled urea was broadcast\\u000a or banded and incorporated in soil 20 days after sowing of rice. Ammonia volatilization was reduced to 3.3 per cent when urea\\u000a supergranules (USG) were used. Coating of USG with DCD or neem cake showed no advantage. Ammonia volatilization

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

    PubMed

    Ghosh, Tanushree; Sarkar, Priyabrata

    2014-12-01

    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

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

    ERIC Educational Resources Information Center

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

    2010-01-01

    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…

  15. Calibration and random variation of the serum creatinine assay as critical elements of using equations to estimate glomerular filtration rate

    Microsoft Academic Search

    Josef Coresh; Brad C. Astor; Geraldine McQuillan; John Kusek; Tom Greene; Frederick Van Lente; Andrew S. Levey

    2002-01-01

    Equations using serum creatinine level, age, sex, and other patient characteristics often are used to estimate glomerular filtration rate (GFR) in both clinical practice and research studies. However, the critical dependence of these equations on serum creatinine assay calibration often is overlooked, and the reproducibility of estimated GFR is rarely discussed. We address these issues in frozen samples from 212

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

    PubMed Central

    2013-01-01

    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

  17. The Action of Certain Acid Reagents on the Substituted Ureas

    E-print Network

    Brewster, Ray Q.

    1915-01-01

    aniline and methyl phenyl urea chloride with pyridine - 6 Di-phenyl ethyl thio urea and phosgene with pyridine 7 Para mono brom di-phenyl thio urea and methyl phenyl urea chloride - 8 Di-phenyl thio urea and chlor formic ethyl ester with pyridine 9...°C. to 150°C. for an hour. A gas was given off which darkened lead acetate paper. The reaction product, a green resinous mass, on distillation with steam, gave phenyl mustard oil and a trace of methyl aniline. The gummy product remaining...

  18. Meta-Analysis of 28,141 Individuals Identifies Common Variants within Five New Loci That Influence Uric Acid Concentrations

    Microsoft Academic Search

    Melanie Kolz; Toby Johnson; Serena Sanna; Alexander Teumer; Veronique Vitart; Markus Perola; Massimo Mangino; Eva Albrecht; Chris Wallace; Martin Farrall; Ĺsa Johansson; Dale R. Nyholt; Yurii Aulchenko; Jacques S. Beckmann; Sven Bergmann; Murielle Bochud; Morris Brown; Harry Campbell; John Connell; Anna Dominiczak; Georg Homuth; Claudia Lamina; Mark I. McCarthy; Thomas Meitinger; Vincent Mooser; Patricia Munroe; Matthias Nauck; John Peden; Holger Prokisch; Perttu Salo; Veikko Salomaa; Nilesh J. Samani; David Schlessinger; Manuela Uda; Uwe Völker; Gérard Waeber; Dawn Waterworth; Rui Wang-Sattler; Alan F. Wright; Jerzy Adamski; John B. Whitfield; Ulf Gyllensten; James F. Wilson; Igor Rudan; Peter Pramstaller; Hugh Watkins; Angela Doering; H.-Erich Wichmann; Tim D. Spector; Leena Peltonen; Henry Völzke; Ramaiah Nagaraja; Peter Vollenweider; Mark Caulfield; Thomas Illig; Christian Gieger

    2009-01-01

    Elevated serum uric acid levels cause gout and are a risk factor for cardiovascular disease and diabetes. To investigate the polygenetic basis of serum uric acid levels, we conducted a meta-analysis of genome-wide association scans from 14 studies totalling 28,141 participants of European descent, resulting in identification of 954 SNPs distributed across nine loci that exceeded the threshold of genome-wide

  19. Serum uric acid level, longitudinal blood pressure, renal function, and long-term mortality in treated hypertensive patients.

    PubMed

    Dawson, Jesse; Jeemon, Panniyammakal; Hetherington, Lucy; Judd, Caitlin; Hastie, Claire; Schulz, Christin; Sloan, William; Muir, Scott; Jardine, Alan; McInnes, Gordon; Morrison, David; Dominiczak, Anna F; Padmanabhan, Sandosh; Walters, Matthew

    2013-07-01

    Uric acid may have a role in the development of hypertension and renal dysfunction. We explored the relationship among longitudinal blood pressure, renal function, and cardiovascular outcomes in a large cohort of patients with treated hypertension. We used data from the Glasgow Blood Pressure Clinic database. Patients with a baseline measure of serum uric acid and longitudinal measures of blood pressure and renal function were included. Mortality data were obtained from the General Register Office for Scotland. Generalized estimating equations were used to explore the relationship among quartiles of serum uric acid, blood pressure, and estimated glomerular filtration rate. Cox proportional hazard models were developed to assess mortality relationships. In total, 6984 patients were included. Serum uric acid level did not influence the longitudinal changes in systolic or diastolic blood pressure but was related to change in glomerular filtration rate. In comparison with patients in the first quartile of serum uric acid, the relative decrease in glomerular filtration rate in the fourth was 10.7 (95% confidence interval, 7.9-13.6 mL/min per 1.73 m(2)) in men and 12.2 (95% confidence interval, 9.2-15.2 mL/min per 1.73 m(2)) in women. All-cause and cardiovascular mortality differed across quartiles of serum uric acid in women only (P<0.001; hazard ratios for all-cause mortality 1.38 [95% confidence interval, 1.14-1.67] for the fourth quartile of serum uric acid compared with the first). Serum uric acid level was not associated with longitudinal blood pressure control in adults with treated hypertension but was related to decline in renal function and mortality in women. PMID:23690348

  20. Non-invasive and transdermal measurement of blood uric acid level in human by electroporation and reverse iontophoresis

    PubMed Central

    Lee, Chih-Kuei; Ching, Congo Tak-Shing; Sun, Tai-Ping; Tsai, Chun-Lang; Huang, Wei; Huang, Hsin-Hung; Kuo, Jen-Fu; Lai, Li-Hang; Chien, Mei-Ya; Tseng, Hsin-Hui; Pan, Hui-Tzu; Huang, Shiow-Yuan; Shieh, Hsiu-Li; Liu, Wei-Hao; Liu, Chia-Ming; Huang, Hsin-Wei

    2010-01-01

    The aim of this study was to find out the optimum combination of electroporation (EP) and reverse iontophoresis (RI) on noninvasive and transdermal determination of blood uric acid level in humans. EP is the use of high-voltage electric pulse to create nano-channels on the stratum corneum, temporarily and reversibly. RI is the use of small current to facilitate both charged and uncharged molecule transportation across the skin. It is believed that the combination of these two techniques has additional benefits on the molecules’ extraction across the human skin. In vitro studies using porcine skin and diffusion cell have indicated that the optimum mode for transdermal uric acid extraction is the combination of RI with symmetrical biphasic direct current (current density = 0.3 mA/cm2; phase duration = 180 s) and EP with 10 pulses per second (voltage = 100 V/cm2; pulse width = 1 ms). This optimum mode was applied to six human subjects. Uric acid was successfully extracted through the subjects’ skin into the collection solution. A good correlation (r2 = 0.88) between the subject’s blood uric acid level and uric acid concentrations in collection solutions was observed. The results suggest that it may be possible to noninvasively and transdermally determine blood uric acid levels. PMID:21187918

  1. Effects of allopurinol on uric acid concentrations, xanthine oxidoreductase activity and oxidative stress in broiler chickens

    Microsoft Academic Search

    M. D. Carro; E. Falkenstein; W. J. Radke; H. Klandorf

    2010-01-01

    The purpose of this study was to determine the effects of allopurinol (AL) on xanthine oxidoreductase (XOR) activity and uric acid (UA) levels in chickens. Thirty 5-week-old broilers were divided into three groups and fed 0 (control), 25 (AL25) or 50 (AL50) mg AL per kg of body mass for 5weeks. Chicks were weighed twice weekly and leukocyte oxidative activity

  2. Effects of allopurinol on plasma uric acid levels in normouricaemic and hyperuricaemic green iguanas (Iguana iguana)

    Microsoft Academic Search

    S. J. Hernandez-Divers; D. Martinez-Jimenez; S. Bush; K. S. Latimer; P. Zwart; E. J. B. Veldhuis Kroeze

    2008-01-01

    A two-phase cross-over therapeutic study was performed with 19 green iguanas (Iguana iguana) maintained within a preferred optimum temperature range of 26 to 37°C. During phase 1, they were fed a normal vegetarian diet and medicated orally with either allopurinol or a placebo control once a day for seven days. Uric acid concentrations, total protein, packed-cell volumes (pcv) and bodyweights

  3. Electrochemical behavior of uric acid at a penicillamine self-assembled gold electrode

    Microsoft Academic Search

    Ling Mei Niu; Nian Bing Li; Wei Jun Kang

    2007-01-01

    .  The fabrication and electrochemical characteristics of a penicillamine (PCA) self-assembled monolayer modified gold electrode\\u000a were investigated. The electrode can enhance the electrochemical response of uric acid (UA), and the electrochemical reaction\\u000a of UA on the PCA electrode has been studied by cyclic voltammetry and differential pulse voltammetry. Some electrochemical\\u000a parameters, such as diffusion coefficient, standard rate constant, electron transfer coefficient

  4. The presence of uric acid, an antioxidantive substance, in fish seminal plasma

    Microsoft Academic Search

    A. Ciereszko; K. Dabrowski; D. Kucharczyk; S. Dobosz; K. Goryczko; J. Glogowski

    1999-01-01

    High concentrations of uric acid in seminal plasma of a range of teleost fish species are reported for the first time. Concentrations of urate amounted to 223.4; 121.9–130.0, 355.9, 735.6, 124.0, 192.7 and 148.0 µM for rainbow trout (Oncorhynchus mykiss), yellow perch (Perca flavescens), muskellunge (Esox masquinongy), Northern pike (Esox lucius), carp koi (Cyprinus carpio), bream (Abramis brama), and tench (Tinca

  5. Relation of serum uric acid to cardiovascular endpoints in hypertension: the life study

    Microsoft Academic Search

    Aud Hřieggen; Sverre E. Kjeldsen; Stevo Julius; Richard B. Devereux; Michael Alderman; Cong Chen; Bjorn Dahlof

    2003-01-01

    Serum uric acid (SUA) has been proposed to be an independent risk factor for cardiovascular morbidity and death. Losartan is uricosuric, in contrast to atenolol and to other AII antagonists. The LIFE study was a double-masked, randomized, parallel-group trial in 9193 patients (54% female) with essential hypertension and left ventricular hypertrophy. The participants received once-daily losartan- or atenolol-based treatment. We

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

    PubMed Central

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

    2014-01-01

    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

  7. Optimization of pH values to formulate the bireagent kit for serum uric acid assay.

    PubMed

    Huang, Ya; Chen, Yuanxiang; Yang, Xiaolan; Zhao, Hua; Hu, Xiaolei; Pu, Jun; Liao, Juan; Long, Gaobo; Liao, Fei

    2015-01-01

    A new formulation of the bireagent kit for serum uric acid assay was developed based on the effects of pH on enzyme stability. At 4 °C, half-lives of uricases from Bacillus fastidious and Arthrobacter globiforms were longer than 15 months at pH 9.2, but became shorter at pH below 8.0; half-lives of ascorbate oxidase and peroxidase were comparable at pH 6.5 and 7.0, but became much shorter at pH higher than 7.4. In the new formulation of the bireagent kit, Reagent A contained peroxidase, 4-aminoantipyrine, and ascorbate oxidase in 50 mM phosphate buffer at pH 6.5; Reagent B contained B. fastidious or A. globiforms uricase in 50 mM sodium borate buffer at pH 9.2; Reagents A and B were mixed at 4:1 to produce a final pH from 7.2 to 7.6 for developing a stable color. The new bireagent kit consumed smaller quantities of three enzymes for the same shelf life. With the new bireagent kit, there were linear responses of absorbance at 546 nm to uric acid up to 34 mM in reaction mixtures and a good correlation of uric acid levels in clinical sera with those by a commercial kit, but stronger resistance to ascorbate. Therefore, the new formulation was advantageous. PMID:24673428

  8. Uric acid transport in brush border membrane vesicles isolated from rabbit kidney.

    PubMed

    Boumendil-Podevin, E F; Podevin, R A; Priol, C

    1979-06-01

    The transport of uric acid was studied in brush border membrane vesicles isolated from rabbit kidney. The uptake of uric acid by the vesicles was osmotically sensitive and occurred in the absence of significant uric acid degradation. Under the conditions used to evaluate transport, urate binding to the membranes represented only 10--15% of the total uptake. The initial rate of uptake was linear over the concentration range 0.04--8 mM urate. Uptake of urage was Na+ gradient independent. It was dependent on external pH and temperature with Q10 near 3. The urate uptake was inhibited reversibly by p-chloromercuribenzoate. Probenecid, ouabain, cyclic adenosine 3',5'--monophosphate, and its dibutyryl derivative had no appreciable effects. Pyrazinoic acid and pyrazinamide stimulated urate uptake. Experiments performed with osmotically shocked vesicles demonstrated that this stimulatory effect resulted from increased binding of urate to the membranes. These results indicate that in several ways urate transport in vesicles resembles that observed with more physiologically intact preparations. PMID:220886

  9. Serum Uric Acid and Ambulatory Blood Pressure in Children with Primary Hypertension

    PubMed Central

    Jones, Deborah P.; Richey, Phyllis A.; Alpert, Bruce S.; Li, Rongling

    2008-01-01

    Hyperuricemia is associated with primary hypertension (HTN) in adults and children. Furthermore, uric acid levels during childhood are associated with blood pressure (BP) levels in adulthood. We measured 24-h ambulatory BP and serum uric acid (SUA) in 104 children referred for possible hypertension. Mean age was 13.7 ± 2.6 y (range 7-18y) with 67 males and 37 females; 74 were African-American, 29 Caucasian and one Asian. SUA was associated with age (r=0.38, P=0.0001) and BMI Z-score (r=0.23, P=0.021). SUA was significantly associated with mean ambulatory systolic (S) and diastolic (D) BP. Mean ambulatory BP was normalized to gender- and height-specific reference standards using BP index. SUA was significantly associated with 24-h DBP index and nocturnal DBP index after adjusting for age, gender, race, BMI Z-score and urinary sodium excretion. SUA was also significantly associated with 24-h DBP load and nocturnal DBP load. Uric acid was significantly associated with increased likelihood for diastolic HTN (OR 2.1, CI 1.2, 3.7; P=0.0063) after adjusting for other co-variables. Among children at risk for HTN, the likelihood for diastolic HTN (as defined by ambulatory blood pressure monitoring) increases significantly as SUA increases. SUA may be associated with increased severity of HTN during youth. PMID:18596575

  10. Mechanism and specificity of increased amylase\\/creatinine clearance ratio in pancreatitis 1

    Microsoft Academic Search

    A. Marten; D. Beales; E. Elias

    1977-01-01

    The amylase\\/creatinine clearance ratio (Cam\\/Ccr ratio) was determined in 239 subjects. In 87 hospitalised patients without pancreatic disease (controls) the Cam\\/Ccr ratio was 3·02 ± 0·69 (mean ± ISD). The ratio was above the normal range in all patients with acute pancreatitis but was normal in those with chronic pancreatitis and carcinoma of the pancreas. In 18 patients with choledocholithiasis

  11. Inflammation and dietary protein intake exert competing effects on serum albumin and creatinine in hemodialysis patients

    Microsoft Academic Search

    George A Kaysen; Glenn M Chertow; Rohini Adhikarla; Belinda Young; Claudio Ronco; Nathan W Levin

    2001-01-01

    Inflammation and dietary protein intake exert competing effects on serum albumin and creatinine in hemodialysis patients.BackgroundCross-sectional studies have shown an inverse correlation between serum C-reactive protein (CRP) and serum albumin concentration in hemodialysis patients. The net effects of inflammation and dietary protein intake on nutritional markers over time are unknown.MethodsTo explore the effects of CRP and normalized protein catabolic rate

  12. Computation and simulation of the structural characteristics of the kidney urea transporter and behaviors of urea transport.

    PubMed

    Wang, Zhe; Yu, Tao; Sang, Jian-Ping; Zou, Xian-Wu; Yan, Chengfei; Zou, Xiaoqin

    2015-04-23

    Urea transporters are a family of membrane proteins that transport urea molecules across cell membranes and play important roles in a variety of physiological processes. Although the crystal structure of bacterial urea channel dvUT has been solved, there lacks an understanding of the dynamics of urea transport in dvUT. In this study, by using molecular dynamics simulations, Monte Carlo methods, and the adaptive biasing force approach, we built the equilibrium structure of dvUT, calculated the variation in the free energy of urea, determined the urea-binding sites of dvUT, gained insight into the microscopic process of urea transport, and studied the water permeability in dvUT including the analysis of a water chain in the pore. The strategy used in this work can be applied to studying transport behaviors of other membrane proteins. PMID:25781365

  13. Genome-Wide Association Study of Serum Creatinine Levels during Vancomycin Therapy

    PubMed Central

    Van Driest, Sara L.; McGregor, Tracy L.; Velez Edwards, Digna R.; Saville, Ben R.; Kitchner, Terrie E.; Hebbring, Scott J.; Brilliant, Murray; Jouni, Hayan; Kullo, Iftikhar J.; Creech, C. Buddy; Kannankeril, Prince J.; Vear, Susan I.; Brothers, Kyle B.; Bowton, Erica A.; Shaffer, Christian M.; Patel, Neelam; Delaney, Jessica T.; Bradford, Yuki; Wilson, Sarah; Olson, Lana M.; Crawford, Dana C.; Potts, Amy L.; Ho, Richard H.; Roden, Dan M.; Denny, Josh C.

    2015-01-01

    Vancomycin, a commonly used antibiotic, can be nephrotoxic. Known risk factors such as age, creatinine clearance, vancomycin dose / dosing interval, and concurrent nephrotoxic medications fail to accurately predict nephrotoxicity. To identify potential genomic risk factors, we performed a genome-wide association study (GWAS) of serum creatinine levels while on vancomycin in 489 European American individuals and validated findings in three independent cohorts totaling 439 European American individuals. In primary analyses, the chromosome 6q22.31 locus was associated with increased serum creatinine levels while on vancomycin therapy (most significant variant rs2789047, risk allele A, ? = -0.06, p = 1.1 x 10-7). SNPs in this region had consistent directions of effect in the validation cohorts, with a meta-p of 1.1 x 10-7. Variation in this region on chromosome 6, which includes the genes TBC1D32/C6orf170 and GJA1 (encoding connexin43), may modulate risk of vancomycin-induced kidney injury. PMID:26030142

  14. The Total Urine Protein-to-Creatinine Ratio Can Predict the Presence of Microalbuminuria

    PubMed Central

    Yamamoto, Kyoko; Yamamoto, Hiroyuki; Yoshida, Katsumi; Niwa, Koichiro; Nishi, Yutaro; Mizuno, Atsushi; Kuwabara, Masanari; Asano, Taku; Sakoda, Kunihiro; Niinuma, Hiroyuki; Nakahara, Fumiko; Takeda, Kyoko; Shindoh, Chiyohiko; Komatsu, Yasuhiro

    2014-01-01

    Background The Kidney Disease: Improving Global Outcomes chronic kidney disease (CKD) guidelines recommend that CKD be classified based on the etiology, glomerular filtration rate (GFR) and degree of albuminuria. The present study aimed to establish a method that predicts the presence of microalbuminuria by measuring the total urine protein-to-creatinine ratio (TPCR) in patients with cardiovascular disease (CVD) risk factors. Methods and Results We obtained urine samples from 1,033 patients who visited the cardiovascular clinic at St. Luke's International Hospital from February 2012 to August 2012. We measured the TPCR and the urine albumin-to-creatinine ratio (ACR) from random spot urine samples. We performed correlation, receiver operating characteristic (ROC) curve, sensitivity, and subgroup analyses. There was a strong positive correlation between the TPCR and ACR (R2?=?0.861, p<0.001). A ROC curve analysis for the TPCR revealed a sensitivity of 94.4%, a specificity of 86.1%, and an area under the curve of 0.903 for detecting microalbuminuria for a TPCR cut-off value of 84 mg/g of creatinine. The subgroup analysis indicated that the cut-off value could be used for patients with CVD risk factors. Conclusions These results suggest that the TPCR with an appropriate cut-off value could be used to screen for the presence of microalbuminuria in patients with CVD risk factors. This simple, inexpensive measurement has broader applications, leading to earlier intervention and public benefit. PMID:24614247

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

    SciTech Connect

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

    1981-01-01

    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).

  16. Enzymatic Characterization of a Prokaryotic Urea Carboxylase

    Microsoft Academic Search

    Takeshi Kanamori; Norihisa Kanou; Haruyuki Atomi; Tadayuki Imanaka

    2004-01-01

    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

  17. 1H and 13C NMR spectra and solution structures of novel derivatives of 5-substituted creatinines.

    PubMed

    Krawczyk, Hanna; Pietras, Agnieszka; Kraska, Anna

    2007-01-01

    Five creatinine derivatives were prepared by the treatment of creatinine with activated carbon and appropriate alcohol (1-4), or ammonia solution (5). Product structures were determined by 1H and 13C NMR spectroscopy in solution, including 2D HSQC and HMBC experiments. Then, the proton and carbon chemical shifts for these compounds were calculated using GIAO-DFT [B3LYP/6-311G(2d,p)] method and the Gaussian 03W program and furthermore for 1 and 5 using polarizable continuum model (PCM). The conclusions coming from the comparison of the experimental and theoretical spectra supported the adopted signal assignments and solved the structural problems due to the potential annular tautomerism of the investigated compounds. One can predict that 5-substituted creatinines, just like creatinine, appear in solution in the form of 2-amino-1,5-dihydro-1-methyl-4-imidazolone. Correlations between experimental and calculated substituent-induced chemical shifts for two tautomeric forms of 5-substituted creatinines indicate that the mechanism of the substituent influence in both tautomers for the investigated compounds appears to be analogous. We can predict that in solution this accepting inductive effect of substituent groups does not significantly influence the structure of creatinine molecule in solution. The analysis of coupling constants for 5-substituted creatinines gives information about conformation of the investigated molecules in solution. PMID:16920395

  18. Dichloridobis(thio-urea-?S)nickel(II).

    PubMed

    Zouihri, Hafid

    2012-03-01

    The title complex, [NiCl(2)(CH(4)N(2)S)(2)], has been synthesized from the previously reported (diamino-methyl-idene)sulfonium chloride-thio-urea (3/2) salt [Zouihri (2012b ?). Acta Cryst. E68, o257]. The Ni(II) ion is coordinated in a distorted tetra-hedral geometry by two mol-ecules of thio-urea [Ni-S = 2.3079?(7) and 2.3177?(6)?Ĺ] and two chloride anions [Ni-Cl = 2.2516?(7) and 2.2726?(7)?Ĺ]. The bond angles at the Ni atom lie between 96.69?(2) and 115.40?(3)°, while the dihedral angle between the mean planes of the two thio-urea ligands is 6.36?(15)°. The crystal structure is characterized by intra- and inter-molecular N-H?Cl hydrogen bonds, which lead to the formation of two-dimensional networks lying parallel to the ab plane. The networks are linked via classical N-H?Cl and N-H?S hydrogen bonds, forming a three-dimensional arrangement. PMID:22412454

  19. Dichloridobis(thio­urea-?S)nickel(II)

    PubMed Central

    Zouihri, Hafid

    2012-01-01

    The title complex, [NiCl2(CH4N2S)2], has been synthesized from the previously reported (diamino­methyl­idene)sulfonium chloride–thio­urea (3/2) salt [Zouihri (2012b ?). Acta Cryst. E68, o257]. The NiII ion is coordinated in a distorted tetra­hedral geometry by two mol­ecules of thio­urea [Ni—S = 2.3079?(7) and 2.3177?(6)?Ĺ] and two chloride anions [Ni—Cl = 2.2516?(7) and 2.2726?(7)?Ĺ]. The bond angles at the Ni atom lie between 96.69?(2) and 115.40?(3)°, while the dihedral angle between the mean planes of the two thio­urea ligands is 6.36?(15)°. The crystal structure is characterized by intra- and inter­molecular N—H?Cl hydrogen bonds, which lead to the formation of two-dimensional networks lying parallel to the ab plane. The networks are linked via classical N—H?Cl and N—H?S hydrogen bonds, forming a three-dimensional arrangement. PMID:22412454

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

    PubMed Central

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

    2013-01-01

    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

  1. Performance of Chronic Kidney Disease Epidemiology Collaboration Creatinine-Cystatin C Equation for Estimating Kidney Function in Cirrhosis

    PubMed Central

    Mindikoglu, Ayse L.; Dowling, Thomas C.; Weir, Matthew R.; Seliger, Stephen L.; Christenson, Robert H.; Magder, Laurence S.

    2013-01-01

    Conventional creatinine-based glomerular filtration rate (GFR) equations are insufficiently accurate for estimating GFR in cirrhosis. The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) recently proposed an equation to estimate GFR in subjects without cirrhosis using both serum creatinine and cystatin C levels. Performance of the new CKD-EPI creatinine-cystatin C equation (2012) was superior to previous creatinine- or cystatin C-based GFR equations. To evaluate the performance of the CKD-EPI creatinine-cystatin C equation in subjects with cirrhosis, we compared it to GFR measured by non-radiolabeled iothalamate plasma clearance (mGFR) in 72 subjects with cirrhosis. We compared the “bias”, “precision” and “accuracy” of the new CKD-EPI creatinine-cystatin C equation to that of 24-hour urinary creatinine clearance (CrCl), Cockcroft-Gault (CG) and previously reported creatinine- and/or cystatin C-based GFR-estimating equations. Accuracy of CKD-EPI creatinine-cystatin C equation as quantified by root mean squared error of difference scores [differences between mGFR and estimated GFR (eGFR) or between mGFR and CrCl, or between mGFR and CG equation for each subject] (RMSE=23.56) was significantly better than that of CrCl (37.69, P=0.001), CG (RMSE=36.12, P=0.002) and GFR-estimating equations based on cystatin C only. Its accuracy as quantified by percentage of eGFRs that differed by greater than 30% with respect to mGFR was significantly better compared to CrCl (P=0.024), CG (P=0.0001), 4-variable MDRD (P=0.027) and CKD-EPI creatinine 2009 (P=0.012) equations. However, for 23.61% of the subjects, GFR estimated by CKD-EPI creatinine-cystatin C equation differed from the mGFR by more than 30%. CONCLUSIONS The diagnostic performance of CKD-EPI creatinine-cystatin C equation (2012) in patients with cirrhosis was superior to conventional equations in clinical practice for estimating GFR. However, its diagnostic performance was substantially worse than reported in subjects without cirrhosis. PMID:23744636

  2. Plasma chemistry references values in psittaciformes.

    PubMed

    Lumeij, J T; Overduin, L M

    1990-04-01

    Reference values for 17 plasma chemical variables in African greys. Amazons, cockatoos and macaws were established for use in avian clinical practice. The inner limits are given for the percentiles P(2.5) and P(97.5) with a probability of 90%. The following variables were studied: urea, creatinine, uric acid, urea/uric acid ratio, osmolality, sodium, potassium, calcium, glucose, aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase, lactate dehydrogenase, creatine kinase, bile acids, total protein, albumin/globulin ratio. Differences between methods used and values found in this study and those reported previously are discussed. PMID:18679934

  3. How the use of creatine supplements can elevate serum creatinine in the absence of underlying kidney pathology.

    PubMed

    Williamson, Lydia; New, David

    2014-01-01

    Serum creatinine is a widely used marker in the assessment of renal function. Elevated creatinine levels suggest kidney dysfunction, prompting the need for further investigation. This report describes a case in which the consumption of the bodybuilding supplement creatine ethyl ester resulted in raised serum creatinine in the absence of true underlying kidney pathology. The abnormalities reversed after discontinuation of the supplement. A case of pseudo renal failure was recognised and kidney function was concluded to be normal. This report aims to address the mechanisms by which the ingestion of creatine ethyl ester can mimic the blood results expected in advanced renal failure, and confronts the problems faced when relying on serum creatinine as a diagnostic tool. PMID:25239988

  4. IMPROVEMENT IN PROPERTIES OF UREA BY PHOSPHOGYPSUM COATING

    Microsoft Academic Search

    Manish Vashishtha; Papireddy Dongara; Dhananjay Singh

    Particle coating is becoming increasingly important in fertilizer, pharmaceutical and food industries. The demand for coating granular fertilizers with minerals is increasing. Urea is coated with PhosphoGypsum, neem oil, polymeric suspensions and micronutrients like sulfer, zinc etc.Coating of PhosphoGypsum on urea fertilizer is a important application of coating process . Coating of urea particles is done to increase nitrogen use

  5. Use of urease inhibitors and urea fertilizers on winter wheat

    Microsoft Academic Search

    AJ Schlegel; DW Nelson; LE Sommers

    1987-01-01

    Phosphoroamide urease inhibitors were evaluated for their ability to increase grain protein and yield of winter wheat (Triticum aestivum L.) when added to surfaceapplied urea-based fertilizers. Six urease inhibitors [trichloroethyl phosphorodiamidate, diethyl phosphoric triamide, dimethyl phosphoric triamide, N-(diaminophosphinyl)-cyclohexylamine, N-benzyl-N-methyl phosphoric triamide, and phenylphosphorodiamide] were evaluated. Nitrogen treatments were urea prills, urea solution, and ureaammonium nitrate (UAN) solution broadcast and UAN

  6. Macrocyclic ureas: A simple building block for supramolecular structures

    Microsoft Academic Search

    Linda S. Shimizu

    There is great interest in developing new building blocks that predictably self-assemble into well-defined supramolecular structures. We have utilized the self-assembly of simple, rigid macrocyclic bis-ureas to reliably form columnar structures. Larger macrocycles assemble into porous crystals containing channels of predetermined dimensions. The self-assembly of these monomers is directed by the formation of strong urea-urea hydrogen bond and by the

  7. Urea and ethanolamine as a mixed plasticizer for thermoplastic starch

    Microsoft Academic Search

    X. F. Ma; J. G. Yu; J. J. Wan

    2006-01-01

    Mixtures of urea and ethanolamine were used as plasticizers for preparing thermoplastic starch (TPS) in a single-screw extruder. The interaction between urea\\/ethanolamine and starch was investigated using Fourier Transform Infrared (FT-IR). Glass transition temperature of TPS was tested by Differential scanning calorimetry (DSC). Both FT-IR and DSC proved that the mixture of urea and ethanolamine could form more stable and

  8. The Physiology and Evolution of Urea Transport in Fishes

    Microsoft Academic Search

    M. D. McDonald; C. P. Smith; P. J. Walsh

    2006-01-01

    This review summarizes what is currently known about urea transporters in fishes in the context of their physiology and evolution\\u000a within the vertebrates. The existence of urea transporters has been investigated in red blood cells and hepatocytes of fish\\u000a as well as in renal and branchial cells. Little is known about urea transport in red blood cells and hepatocytes, in

  9. Urea and glutamine synthesis: Environmental influences on nitrogen excretion

    Microsoft Academic Search

    Paul M. Anderson

    2001-01-01

    The focus of this chapter is on recent developments in our understanding of the expression of the urea cycle and the roles of glutamine synthetase (GSase) and glutamine-dependent carbamoyl-phosphate synthetase (CPSase III) in ammonia detoxification in fish, with emphasis on teleosts. Marine elasmobranch fishes have an active urea cycle, synthesizing and retaining urea for the purpose of osmoregulation. Well-characterized biochemical

  10. Serial blood pressure measurements and exogenous creatinine clearance rates in partially nephrectomized dogs: the effect of dietary sodium intake 

    E-print Network

    Greco, Deborah Susan

    1987-01-01

    SERIAL BIOOD PRESSURE MEASUREMENTS AND EXOGENOUS CREATININE CLEARANCE RATES IN PARTIALLY NEPHRECTOM IZED DOGS: THE EFFECT OF DIETARY SODIUM INTAKE A Thesis DEBORAH SUSAN GRECO Submitted to the Graduate College of Texas A&M University... in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1987 Major Subject: Veterinary Medicine and Surgery SERIAL BLOOD PRESSURE MEASUREMENTS AND EXOGENOUS CREATININE CLEARANCE RATES IN PARTIALLY NEPHRECIOMIZED DOGS...

  11. Urea in the management of advanced malignancies (preliminary report).

    PubMed

    Gandhi, G M; Anasuya, S R; Kawathekar, P; Bhaskarmall; Krishnamurthy, K R

    1977-01-01

    Twenty cases of advanced (Stage III) cancer of the cervix were treated with intratumour injection of 40% urea solution and local application of 50% urea ointment. Sixty percent of these patients had beneficial effect and in 25% of the patients there was minimal response. Patients with multiple secondaries in liver had very good symptomatic relief with oral urea. Urea therapy is a simple, cheap, and safe method of treating advanced stages of cancer, where very little can be done by the accepted lines of treatment such as surgery or radiotherapy. This line of treatment can be practiced even in a consulting room or primary health center. PMID:266635

  12. Urinary protein-to-creatinine ratio versus 24-h proteinuria in the screening for nephropathy in HIV patients.

    PubMed

    Antonello, Vicente Sperb; Poli-De-Figueiredo, Carlos Eduardo; Antonello, Ivan Carlos Ferreira; Tovo, Cristiane Valle

    2015-06-01

    To determine the correlation between protein-to-creatinine ratio and 24-h urinary protein, proteinuria was measured in 45 patients attending a public HIV clinic in Porto Alegre, Brazil, using 24-h urinary protein excretion (24hUP) and urinary protein-to-creatinine ratio. Spearman's correlation test was done to evaluate the association between spot protein-to-creatinine ratio and 24hUP. The limits of agreement between the two methods were analysed by the Bland-Altman method. For protein excretion <1?g/day, limits (95%) of agreement of protein-to-creatinine ratio and 24hUP were +0.112 and -0.097?g/day. A strong correlation (r?=?0.957) was found between protein-to-creatinine ratio and 24hUP excretion. The conclusion is that the protein-to-creatinine ratio in spot urine specimens is an accurate, convenient and reliable screening method to estimate the urinary protein excretion in HIV patients to detect abnormal urinary protein loss. Further studies are required to evaluate renal disease in HIV patients with chronic renal disease and higher urinary protein excretion. PMID:25015935

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

    PubMed

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

    2014-04-20

    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

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

    NASA Astrophysics Data System (ADS)

    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

    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).

  15. Analysis of metformin, sitagliptin and creatinine in human dried blood spots.

    PubMed

    Scherf-Clavel, Maike; Högger, Petra

    2015-08-01

    For analysis of the anti-diabetic drugs metformin and sitagliptin and the renal clearance marker creatinine in the same human dried blood spot (DBS) extract two liquid chromatography methods employing HPLC/UV and LC-ESI-MS/MS have been developed and validated. An accurate volume of 40?L blood was spotted on a sampling paper which was extracted using 90% acetonitrile with 10% formic acid. The new methods were shown to be selective, accurate and precise. The validated ranges were 0.2-5?g/mL for metformin, 1.5-15?g/mL for creatinine and 3-500ng/mL for sitagliptin. Since drug analysis in DBS determines whole blood concentrations as opposed to the typically used plasma levels the partition ratios between human plasma and blood cells, c(P)/c(BC), were elucidated in vitro to gain insight into the significance of blood cells as compartment of distribution for both compounds. The c(P)/c(BC) was found to be 4.65±0.73 for metformin and 5.58±0.98 for sitagliptin. While an accumulation of metformin in erythrocytes was already known we now present the first evidence that sitagliptin distributes into human blood cells. The analytical methods were also successfully applied to authentic capillary blood samples from two diabetic patients regularly taking a combination of metformin and sitagliptin. Both samples revealed analyte trough concentrations well above the lower limit of quantification of the respective compounds. Therefore, the present study offers a methodological basis for the DBS analysis of metformin and sitagliptin in relation to the patients' creatinine concentration. PMID:26121599

  16. Uric acid and IGF1 as possible determinants of FGF23 metabolism in children with normal renal function

    PubMed Central

    Bacchetta, Justine; Cochat, Pierre; Salusky, Isidro B; Wesseling-Perry, Katherine

    2013-01-01

    Background Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone and a suppressor of renal 1? hydroxylase. Although circulating values of FGF23 are increased in early chronic kidney disease (CKD), the interplay between FGF23 levels, growth and nutritional biomarkers has not been evaluated in children with normal renal function. Methods We performed a secondary analysis of the cross-sectional observational INU23 study in 98 children (51 boys, mean age 10.5 ± 3.9 years) with preserved renal function (glomerular filtration rate (GFR) 114 ± 14 ml/min/1.73 m2). Results In bivariate analyses, C-terminal FGF23 levels were positively related to phosphorus and uric acid levels. Intact FGF23 levels were positively associated with uric acid and insulin growth factor 1 (IGF1) levels, with similar results for age, body mass index (BMI), and 25OH vitamin D (25(OH) D). By multivariable analyses, 25(OH)D, uric acid, and phosphorus were independent predictors of C-terminal FGF23, while 25(OH)D, uric acid, and IGF1 were independent predictors of intact FGF23. Conclusions In children with preserved kidney function, the association between FGF23, uric acid, and IGF1 suggests that FGF23 could be an early nutritional indicator of high protein and phosphate intake. The association between FGF23 and IGF1 also suggests a relationship between FGF23 and growth, and warrants further investigation. PMID:22311343

  17. Surface modification of vesicles with methylol urea

    Microsoft Academic Search

    Jin-Chul Kim; Jong-Duk Kim

    2002-01-01

    Surface-modified vesicles were prepared using N-[3-(dimethylamino)propyl]-octadecanamide and stearic acid as bilayer-forming lipids, and N-methylol urea-dodecylamine conjugated (MU-DOA) as a surface modifier. The conjugation of MU to DOA was confirmed by FTIR\\u000a spectra. MU-DOA was incorporated into the vesicles by co-homogenization of the lipids and MU-DOA, and the incorporated MU-DOA\\u000a was then reacted with MU in aqueous bulk phase through a

  18. Nitrous oxide emissions from anhydrous ammonia, urea, and polymer-coated urea in illinois cornfields.

    PubMed

    Fernández, Fabián G; Terry, Richard E; Coronel, Eric G

    2015-03-01

    The use of alternative N sources relative to conventional ones could mitigate soil-surface NO emissions. Our objective was to evaluate the effect of anhydrous ammonia (AA), urea, and polymer-coated urea (ESN) on NO emissions for continuous corn ( L.) production. Corn received 110 kg N ha in 2009 and 180 kg N ha in 2010 and 2011. Soil NO fluxes were measured one to three times per week early in the growing season and less frequently later, using vented non-steady state closed chambers and a gas chromatograph. Regardless of N source, NO emissions were largest immediately after substantial (>20 mm) rains, dropping to background levels thereafter. Averaged across N sources, 2.85% of the applied N was lost as NO. Emission differences for treatments only occurred in 2010, the year with maximum NO production. In the 2010 growing season, cumulative emissions (in kg NO-N ha) were lowest for the check (2.21), followed by ESN (9.77), and ESN was lower than urea (14.07) and AA (16.89). Emissions in 2010 based on unit of corn yield produced followed a similar pattern, and NO emissions calculated as percent of applied N showed that AA losses were 1.9 times greater than ESN. Across years, relative to AA, ESN reduced NO emissions, emissions per unit of corn yield, and emissions per unit of N applied, whereas urea produced intermediate values. The study indicates that, under high N loss potential (wet and warm conditions), ESN could reduce NO emissions more that urea and AA. PMID:26023960

  19. Serum Cystatin-C Is Not Superior to Serum Creatinine in Predicting Glomerular Filtration Rate in Cirrhotic Patients

    PubMed Central

    Nasseri-Moghaddam, Siavosh; Ganji, Mohamad-Reza; Kochari, Mohammad-Reza; Tofangchiha, Shahnaz

    2013-01-01

    BACKGROUND Assessment of glomerular filtration rate (GFR) by common creatininebased methods is potentially inaccurate in patients with cirrhosis. Cirrhotic patients have several underlying conditions that contribute to falsely low serum creatinine concentrations, even in the presence of moderate to severe renal impairment. Therefore creatinine-based methods usually overestimate true GFR in these patients. Cystatin-C is a low molecular weight protein and an endogenous marker of GFR. We compared the accuracy of plasma cystatin-C and creatinine in assessing renal function in cirrhotic patients. METHODS We serially enrolled cirrhotic patients with stable renal function admitted in our ward if they met the inclusion criteria and consented to participate. Child-Pugh (CP) score was calculated for all patients. GFR was calculated using serum creatinine, serum cystatin-C, and 99m TC-DTPA clearance with the last one serving as the gold standard. The area under curve (AUC) on receiveroperating characteristic curves (ROC) were used to assess the diagnostic accuracy of each calculated GFR with that measured by DTPA. RESULTS Fourty-eight patients were enrolled (32 males, 66.7%). Nine were in class-A, 20 in class-B and 19 in class-C of CP. Cystatin-C did not perform well in predicting the true GFR, while serum creatinine performed relatively accurately at GFR<80ml/min (AUC=0.764, p=0.004). Serum creatinine at a cutoff of 1.4 mg/dl was 20% sensitive & 92% specific and with at a cutoff of 0.9 mg/dl was 77%sensitive & 72% specific for diagnosis of impaired renal function. Cystatin-C could not predict GFR effectively even after stratification for CP score, gender, and BMI. Serum creatinine could predict GFR<65ml/min in females (ROC curve AUC=0.844, p=0.045). In those with BMI>20 kg/m2 a GFR<80 ml/min could also be predicted by serum creatinine (ROC curve AUC=0.739, p=0.034). It also could predict GFR<80ml/min in patients with CP class A & B (ROC curve AUC=0.795, p=0.01), but not in patients with CP class C. CONCLUSION Neither serum creatinine nor Cystatin-C are good predictors of GFR in cirrhotic patients, although serum creatinine seems to perform better in selected subgroups. PMID:24829693

  20. Early-onset metabolic syndrome in mice lacking the intestinal uric acid transporter SLC2A9

    PubMed Central

    DeBosch, Brian J.; Kluth, Oliver; Fujiwara, Hideji; Schürmann, Annette; Moley, Kelle

    2015-01-01

    Excess circulating uric acid, a product of hepatic glycolysis and purine metabolism, often accompanies metabolic syndrome. However, whether hyperuricemia contributes to development of metabolic syndrome or is merely a by-product of other processes that cause this disorder has not been resolved. Additionally, how uric acid is cleared from the circulation is incompletely understood. Here, we present a genetic model of spontaneous, early-onset metabolic syndrome in mice lacking the enterocyte urate transporter Glut9 (encoded by the SLC2A9 gene). Glut9-deficient mice develop impaired enterocyte uric acid transport kinetics, hyperuricemia, hyperuricosuria, spontaneous hypertension, dyslipidemia, and elevated body fat. Allopurinol, a xanthine oxidase inhibitor, can reverse the hypertension and hypercholesterolemia. These data provide evidence that hyperuricemia per se could have deleterious metabolic sequelae. Moreover, these findings suggest that enterocytes may regulate whole-body metabolism, and that enterocyte urate metabolism could potentially be targeted to modulate or prevent metabolic syndrome. PMID:25100214

  1. Physical Activity Alters Urinary Albumin/ Creatinine Ratio in Type 1 Diabetic Patient

    PubMed Central

    Tuncel, Ercan; Erturk, Erdinc; Ersoy, Canan; Kiyici, Sinem; Duran, Cevdet; Kuru, Nesrin; Imamoglu, Sazi

    2004-01-01

    While the best way to identify microalbuminuria is to determine albumin excretion rate (AER) in a 24 h urine sample. Published data have shown that calculation of an albumin/creatinine ratio (ACR) in a spot urine sample has reasonable rate of sensitivity and specificity. We aimed to evaluate the effect of daily exercise on ACR and estimate the best time for the examination of the ACR in a spot urine sample. Sixteen eligible patients with Type 1 diabetes mellitus were asked to perform varying degree of exercise periods. Urinary albumin and creatinine excretion rates during each period were determined. ACR and AER of timed urinary samples were compared with the 24 hour urinary AER. We found significant correlations between timed and 24 hour urinary AER. According to diagnostic performance tests, ACR and AER of timed urine samples were both found to be significantly more sensitive during resting period when compared with mild or moderate active periods. It is concluded that ACR and AER of a timed urine sample are sensitive and specific methods for determining microalbuminuria, while overnight resting samples give the impression of being more diagnostic. Key Points Timed urine samples can predict microalbuminuria but because of the erroneous urine collections, microalbuminuria measurement should be calculated with creatiniuria measurement. With increasing physical activity during urine collection diagnostic performances of the cut-off values go downhill. For detecting microalbuminuria best results are reached with the early-morning urine samples. PMID:24497821

  2. Microalbuminuria in diabetes mellitus: Association with age, sex, weight, and creatinine clearance

    PubMed Central

    Chowta, N. K.; Pant, P.; Chowta, M. N.

    2009-01-01

    Studies in the Western literature show a linear relationship between degree of microalbuminuria and body mass index (BMI), blood pressure, and duration of diabetes. This study was aimed to determine the correlation of microalbuminuria with age, sex, duration of diabetes, BMI, and creatinine clearance in type-2 diabetics in Indian population. One hundred patients (59 males and 41 females) with type-2 diabetes mellitus of duration six months or more and negative for albumin in urine by albustic method were included in the study. Detailed clinical history was taken followed by a thorough physical examination that included neurological examination in the selected patients. Micral test was used for estimation of microalbuminuria. Overall prevalence of microalbuminuria in the present study was 37%. Among the patients with microalbuminuria, 20 were males and 17 were females. Pearson correlation of microalbuminuria with age showed statistically significant linear relationship. Gender-wise correlation analysis of microalbuminuria failed to show any statistical significance. Correlation of microalbuminuria with BMI was also not significant (r = 0.063, P > 0.05). Creatinine clearance negatively correlated with microalbuminuria, but this was statistically insignificant. There was a statistically significant correlation of microalbuminuria with duration of diabetes. Prevalence of microalbuminuria is around 37% in type-2 diabetes mellitus. Incidence of microalbuminuria increases with age as well as with increased duration of diabetes mellitus. There is no effect of BMI and sex on the prevalence of microalbuminuria. PMID:20368924

  3. Low Baseline Urine Creatinine Excretion Rate Predicts Poor Outcomes among Critically Ill Acute Stroke Patients

    PubMed Central

    Hsu, Chia-Yu; Wu, Yi-Ling; Cheng, Chun-Yu; Lee, Jiann-Der; Huang, Ying-Chih; Lee, Ming-Hsueh; Wu, Chih-Ying; Hsu, Huan-Lin; Lin, Ya-Hui; Huang, Yen-Chu; Yang, Hsin-Ta; Yang, Jen-Tsung; Lee, Meng; Ovbiagele, Bruce

    2015-01-01

    Urinary creatinine excretion rate (CER) is an established marker of muscle mass. Low CER has been linked to poor coronary artery disease outcomes, but a link between CER and acute stroke prognosis has not been previously explored. We prospectively collected data from patients with acute stroke (ischemic or hemorrhagic) within 24 hours from symptom onset in a Neurological and Neurosurgery Intensive Care Unit in Taiwan. Baseline CER (mg/d) was calculated by urine creatinine concentration in morning spot urine multiplies 24-hour urine volume on the second day of admission. Patients were divided into 3 tertiles with highest, middle, and lowest CER. Primary endpoint was poor outcome defined as modified Rankin Scale 3-6 at 6 months. Among 156 critically ill acute stroke patients meeting study entry criteria, average age was 67.9 years, and 83 (53.2%) patients had ischemic stroke. Patients with lowest CER (vs. highest CER) had a high risk of poor outcome at 6-month after adjustment (odds ratio 4.96, 95% confidence interval 1.22 to 20.15, p value = 0.025). In conclusion, low baseline CER, a marker of muscle mass, was independently associated with poor 6-month outcome among critically ill acute stroke patients. We speculate that preservation of muscle mass through exercise or protein-energy supplement might be helpful for improving prognosis in severe stroke patients. PMID:25557376

  4. 64 FR 48360 - Final Result of Expedited Sunset Review: Solid Urea from Romania

    Federal Register 2010, 2011, 2012, 2013, 2014

    1999-09-03

    ...Expedited Sunset Review: Solid Urea from Romania AGENCY: Import Administration, International...Expedited Sunset Review on Solid Urea from Romania...antidumping duty order on solid urea from Romania pursuant to section 751(c) of the...

  5. 64 FR 62653 - Continuation of Antidumping Duty Orders: Solid Urea From Belarus, Estonia, Lithuania, Romania...

    Federal Register 2010, 2011, 2012, 2013, 2014

    1999-11-17

    ...Urea From Belarus, Estonia, Lithuania, Romania, Russia, Tajikistan, Turkmenistan...urea from Belarus, Estonia, Lithuania, Romania, Russia, Tajikistan, Turkmenistan...antidumping duty order on solid urea from Romania would be likely to lead to...

  6. 76 FR 78885 - Solid Urea From the Russian Federation and Ukraine: Continuation of Antidumping Duty Orders

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-20

    ...A-823-801] Solid Urea From the Russian Federation and Ukraine: Continuation of...orders on solid urea from the Russian Federation (Russia) and Ukraine would likely lead...See Solid Urea From the Russian Federation and Ukraine: Final...

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

    PubMed Central

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

    2014-01-01

    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

  8. 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

    Roman Kand'ár; Pavla Žáková; Vladimíra Mužáková

    2006-01-01

    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

  9. Nonhepatic hyperammonemic encephalopathy due to undiagnosed urea cycle disorder

    PubMed Central

    Nugent, Kenneth

    2015-01-01

    Ornithine transcarbamoylase deficiency is the most common inherited urea cycle disorder. In adults, its phenotypes are diverse. In asymptomatic patients with late presentations, symptom onset is often associated with a precipitating factor. We present a case of a woman with urea cycle disorder diagnosed after an acute peptic ulcer bleed and fasting. PMID:26130895

  10. Nitrification and Anammox with Urea as the Energy Source

    Microsoft Academic Search

    A. Olav Sliekers; Suzanne Haaijer; Markus Schmid; Harry Harhangi; Karin Verwegen; J. Gijs Kuenen; Mike S. M. Jetten

    2004-01-01

    Urea is present in many ecosystems and can be used as an energy source by chemolithotrophic aerobic ammonia oxidizing bacteria (AOB). Thus the utilization of urea in comparison to ammonia, by AOB as well as anaerobic ammonia oxidizing (Anammox) bacteria was investigated, using enrichments cultures, inoculated with activated sludge, and molecular ecological methods. In batch enrichment cultures grown with ammonia

  11. Evidence for Urea-Induced Hypometabolism in Isolated

    E-print Network

    Lee Jr., Richard E.

    to reduced metabolism of hibernating wood frogs (Rana sylvatica). Urea accumulation during dormancy (Malaclemys terrapin), and Gastropoda (Anguispira alternata), and one amphibian species (R. pipiens) that does treatment. However, _VO2 of organs from R. pipiens, the one species tested that does not accumulate urea

  12. 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...

  13. Molecular Basis of the Apparent Near Ideality of Urea Solutions

    PubMed Central

    Kokubo, Hironori; Rösgen, Jörg; Bolen, D. Wayne; Pettitt, B. Montgomery

    2007-01-01

    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. PMID:17693466

  14. Efficiency and future potential of urea for temperate grassland

    Microsoft Academic Search

    C. J. Watson; R. J. Stevens; M. K. Garrett; C. H. McMurray

    1990-01-01

    The efficacy of urea as a grassland fertilizer under temperate conditions has been assessed in a wide variety of comparisons with either ammonium nitrate or calcium ammonium nitrate (CAN). Data from the British Isles have been evaluated and compared to results mainly from continental Europe.In general urea is as good as CAN early in the growing season, but less-effective in

  15. Fate and efficiency of urea fertilizer in wetland rice soil

    Microsoft Academic Search

    Sakorn Phongpan; Sorasith Vacharotayan; Kikuo Kumazawa

    1988-01-01

    Pot experiments conducted with a non-acid marine soil (Typic Tropaquepts) from the Central Region of Thailand showed that in general, urea, DAP, MAP, and urea supergranule were equally effective for increasing rice yield. Evidence indicated that soil incorporation of N fertilizers was superior to the broadcasting method. The grain and straw yields as well as N uptake by rice increased

  16. Foliar applied urea improves freezing protection to avocado and peach

    Microsoft Academic Search

    S. Zilkah; Z. Wiesmann; I. Klein; I. David

    1996-01-01

    The effect of foliar applied urea on freeze hardiness was evaluated under orchard and laboratory conditions. Freezing injury and senescence of avocado (Persea americana Mill.) cv. ‘Hass’ leaves in the orchard was inversely correlated to N content. Three foliar applications of 2% low-biuret urea caused a 26% nitrogen enrichment of leaves. Consequently, leaf freezing hardiness was increased and senescence retarded.

  17. Variability of urea concentration in camel milk in Kazakhstan

    E-print Network

    Paris-Sud XI, Université de

    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

  18. Relative ammonia loss from urea-based fertilizers applied to rice under different hydrological situations

    Microsoft Academic Search

    S. K. Patel; D. Panda; S. K. Mohanty

    1989-01-01

    Relative ammonia volatilization loss from prilled urea, urea supergranule (USG), neem cake-coated urea (NCU), rock phosphate-coated urea (RPCU), gypsum-coated urea (GCU), and prilled urea supplemented with dhaincha (Sesbania aculeata) green manure (Dh + PU) was measured in the fields under different hydrological situations of rice growing. Ammoniacal-N and pH of flood water were less with point placement of USG and

  19. Structure and permeation mechanism of a mammalian urea transporter

    PubMed Central

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

    2012-01-01

    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 ?. 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. PMID:22733730

  20. Determination of uric acid in plasma and allantoic fluid of chicken embryos by capillary electrophoresis.

    PubMed

    Matejcková, Jana; T?ma, Petr; Samcová, Eva; Zemanová, Zdenka

    2007-08-01

    Capillary electrophoresis with diode array detection (DAD) was used to determine uric acid (UA) in chicken plasma and the allantoic fluid of chicken embryos. Complete separation of uric and ascorbic acids was attained in less than 10 min in the optimized BGE containing 60 mM MES + 30 mM Tris + 0.001% (w/v) polybrene (pH 6.1). The limit of UA detection (0.2 mg/L) was found to be low enough for sensitive analysis of native plasma and allantoic fluid samples. Range of linearity (1-200 mg/L), repeatability for peak area (CV <4.1%) and migration time (CV < 2.5%), as well as recovery of UA from biological samples (97-100%), were found to be satisfactory. The method was applied to detect the elevated UA concentrations (hyperuricemia) in chicken embryos with induced unilateral renal agenesis. CE/DAD analysis of the chicken plasma can be carried out with a relatively small volume of samples (1 microL). PMID:17638368

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

    USGS Publications Warehouse

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

    2003-01-01

    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.

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

    PubMed

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

    2003-10-01

    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. PMID:14733290

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

    PubMed

    Amiri, Mandana; Imanzadeh, Hamideh; Banaei, Alireza

    2015-02-01

    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

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

    PubMed

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

    2013-05-01

    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

  5. Uric acid as a danger signal in gout and its comorbidities

    PubMed Central

    Rock, Kenneth L.; Kataoka, Hiroshi; Lai, Jiann-Jyh

    2013-01-01

    Uric acid is a waste product of purine catabolism. This molecule comes to clinical attention when it nucleates to form crystals of monosodium urate (MSU) in joints or other tissues and thereby causes the inflammatory disease of gout. Patients with gout also frequently suffer from a number of co-morbid conditions including hypertension, diabetes mellitus and cardiovascular disease. Why MSU crystals trigger inflammation and are associated with comorbidities of gout has been unclear, but recent studies provide new insights these issues. Rather than simply being a waste product, uric acid could serve a pathophysiological role as a local alarm signal that alerts the immune system to cell injury and helps to trigger both innate and adaptive immune responses. The inflammatory component of these immune responses is caused when urate crystals trigger both inflammasome-dependent and independent pathways to generate the proinflammatory cytokine IL-1. The resulting bioactive IL-1 stimulates the inflammation of gout and might contribute to the development of other comorbidities. Surprisingly, the same mechanisms underlie the inflammatory response to a number of irritant particles, many of which also cause disease. These new insights help to explain the pathogenesis of gout and point to potential new therapeutic targets for this and other sterile inflammatory diseases. PMID:22945591

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

    PubMed

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

    2014-01-01

    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

  7. Dispersion interactions between urea and nucleobases contribute to the destabilization of RNA by urea in aqueous solution.

    PubMed

    Kasavajhala, Koushik; Bikkina, Swetha; Patil, Indrajit; MacKerell, Alexander D; Priyakumar, U Deva

    2015-03-01

    Urea has long been used to investigate protein folding and, more recently, RNA folding. Studies have proposed that urea denatures RNA by participating in stacking interactions and hydrogen bonds with nucleic acid bases. In this study, the ability of urea to form unconventional stacking interactions with RNA bases is investigated using ab initio calculations (RI-MP2 and CCSD(T) methods with the aug-cc-pVDZ basis set). A total of 29 stable nucleobase-urea stacked complexes are identified in which the intermolecular interaction energies (up to -14 kcal/mol) are dominated by dispersion effects. Natural bond orbital (NBO) and atoms in molecules (AIM) calculations further confirm strong interactions between urea and nucleobases. Calculations on model systems with multiple urea and water molecules interacting with a guanine base lead to a hypothesis that urea molecules along with water are able to form cage-like structures capable of trapping nucleic acid bases in extrahelical states by forming both hydrogen-bonded and dispersion interactions, thereby contributing to the unfolding of RNA in the presence of urea in aqueous solution. PMID:25668757

  8. Effect of treatment of hyperuricemia with allopurinol on blood pressure, creatinine clearence, and proteinuria in patients with normal renal functions

    Microsoft Academic Search

    Mehmet Kanbay; Adem Ozkara; Yusuf Selcoki; Bunyamin Isik; Faruk Turgut; Nuket Bavbek; Ebru Uz; Ali Akcay; Ramazan Yigitoglu; Adrian Covic

    2007-01-01

    Background  Hyperuricemia has been associated with the development of hypertension, cardiovascular, and renal disease. However, there\\u000a is no data about the effect of lowering uric acid level on hypertension, renal function, and proteinuria in patients with\\u000a glomerular filtration rate (GFR) >60 ml\\/min. We therefore conducted a prospective study to investigate the benefits of allopurinol\\u000a treatment in hyperuricemic patients with normal renal function.

  9. Amylase/creatinine clearance ratio in diabetic ketoacidosis: a case report.

    PubMed

    Boybeyi, Ozlem; Ergür, Ayça Törel; Dursun, Zarife Esra; Gülerman, Fulya

    2014-11-01

    Diabetic ketoacidosis (DKA) accompanies any other intra-abdominal pathology. Serum amylase/lipase levels are commonly used in order to rule out acute pancreatitis in patients having abdominal pain in DKA. A more specific and noninvasive diagnostic tool - amylase/creatinine clearance ratio (ACCR) - can be used to rule out pancreatitis in patients with DKA. A 14-year-old girl was admitted with abdominal pain and nausea. She had been followed up for type 1 diabetes mellitus for the last 5 years. The serum amylase levels were increased up to 687 U/L (normal: 28-120 U/L) on the third day of hospitalization. Simultaneous serum and urinary amylase concentrations were measured, and ACCR was calculated (1.2%). The diagnosis of pancreatitis was ruled out. The serum amylase levels decreased in the following days, and she was discharged. ACCR determination is a simple and specific test to diagnose pancreatitis, especially in patients with DKA. PMID:25153214

  10. Glomerular filtration rate estimation using cystatin C alone or combined with creatinine as a confirmatory test

    PubMed Central

    Fan, Li; Inker, Lesley A.; Rossert, Jerome; Froissart, Marc; Rossing, Peter; Mauer, Michael; Levey, Andrew S.

    2014-01-01

    Background Glomerular filtration rate (GFR) estimating equations using the combination of creatinine and cystatin C (eGFRcr-cys) are more accurate than equations using either alone (eGFRcr or eGFRcys). New guidelines suggest measuring cystatin C as a confirmatory test when eGFRcr may be inaccurate, but do not specify demographic or clinical conditions in which eGFRcys or eGFRcr-cys are more accurate than eGFRcr nor which estimate to use in such circumstances. Methods We compared the performance of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in 1119 subjects in the CKD-EPI cystatin C external validation dataset. Subgroups were defined by eGFRcr, age, sex, diabetes status and body mass index (BMI). The reference test was GFR measured using urinary or plasma clearance of exogenous filtration markers. Cystatin C and creatinine assays were traceable to primary reference materials. Accuracy was defined as the absolute difference in eGFR compared with mGFR. Results The mean mGFR was 70 ± 41 (SD) mL/min/1.73 m2. eGFRcys was more accurate than eGFRcr at lower BMI and less accurate at higher BMI, especially at higher levels of eGFRcr. There were small differences in accuracy in people according to the diabetes status. eGFRcr-cys was as accurate or more accurate than eGFRcr or eGFRcys in these and all other subgroups. Conclusions eGFRcr-cys, but not eGFRcys, is more accurate than eGFRcr in most subgroups we studied, suggesting preferential use of eGFRcr-cys when serum cystatin C is measured as a confirmatory test to obtain more accurate eGFR. Further studies are necessary to evaluate diagnostic strategies for using eGFRcys and eGFRcr-cys. PMID:24449101

  11. Relationship between High-Performance Liquid Chromatography Fingerprints and Uric Acid-Lowering Activities of Cichorium intybus L.

    PubMed

    Zhu, Chun-Sheng; Zhang, Bing; Lin, Zhi-Jian; Wang, Xue-Jie; Zhou, Yue; Sun, Xiao-Xia; Xiao, Ming-Liang

    2015-01-01

    This study aimed to explore the spectrum-effect relationships between high-performance liquid chromatography fingerprints and the uric acid-lowering activities of chicory. Chemical fingerprints of chicory samples from ten different sources were determined by high-performance liquid chromatography, and then investigated by similarity analysis and hierarchical clustering analysis. Pharmacodynamics experiments were conducted in animals to obtain the uric acid-lowering activity information of each chicory sample. The spectrum-effect relationships between chemical fingerprints and the uric acid-lowering activities of chicory were established by canonical correlation analysis. The structures of potential effective peaks were identified by liquid chromatography with tandem mass spectrometry. The results showed that a close correlation existed between the spectrum and effect of chicory. Aesculin, chlorogenic acid, chicoric acid, isochlorogenic acid A/B/C and 13,14-seco-stigma5(6),14(15)-diene-3?-ol might be the main effective constituents. This work provides a general model of the combination of high-performance liquid chromatography and uric acid-lowering activities to study the spectrum-effect relationships of chicory, which can be used to discover the principle components responsible for the bioactivity. PMID:26007193

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

    PubMed

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

    2013-04-01

    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

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

    Microsoft Academic Search

    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

    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

  14. Uric Acid Accumulation in an Arabidopsis Urate Oxidase Mutant Impairs Seedling Establishment by Blocking Peroxisome Maintenance[W

    PubMed Central

    Hauck, Oliver K.; Scharnberg, Jana; Escobar, Nieves Medina; Wanner, Gerhard; Giavalisco, Patrick; Witte, Claus-Peter

    2014-01-01

    Purine nucleotides can be fully catabolized by plants to recycle nutrients. We have isolated a urate oxidase (uox) mutant of Arabidopsis thaliana that accumulates uric acid in all tissues, especially in the developing embryo. The mutant displays a reduced germination rate and is unable to establish autotrophic growth due to severe inhibition of cotyledon development and nutrient mobilization from the lipid reserves in the cotyledons. The uox mutant phenotype is suppressed in a xanthine dehydrogenase (xdh) uox double mutant, demonstrating that the underlying cause is not the defective purine base catabolism, or the lack of UOX per se, but the elevated uric acid concentration in the embryo. Remarkably, xanthine accumulates to similar levels in the xdh mutant without toxicity. This is paralleled in humans, where hyperuricemia is associated with many diseases whereas xanthinuria is asymptomatic. Searching for the molecular cause of uric acid toxicity, we discovered a local defect of peroxisomes (glyoxysomes) mostly confined to the cotyledons of the mature embryos, which resulted in the accumulation of free fatty acids in dry seeds. The peroxisomal defect explains the developmental phenotypes of the uox mutant, drawing a novel link between uric acid and peroxisome function, which may be relevant beyond plants. PMID:25052714

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

    PubMed Central

    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

    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

  16. Preparation and characterization of urea-oxalic acid solid form

    NASA Astrophysics Data System (ADS)

    Onija, Oana; Borodi, Gh.; Kacso, Irina; Pop, M. N.; Dadarlat, D.; Bratu, I.; Jumate, N.

    2012-02-01

    The selective production of crystalline polymorphs is an outstanding problem in solid-state chemistry. In this study, the preparation of a new urea solid form is based on pure urea and oxalic acid (1:1), by grinding the components at room temperature. The resulted compound was investigated by X-ray powder diffraction (PXRD), thermal analysis (DSC, PPE) and infrared (FTIR) spectroscopy. The difference between the PXRD patterns of urea-oxalic acid and of the starting components evidenced a new compound. Using X-ray powder diffraction method, the lattice parameters were determined. Some thermal properties of the obtained compound were also investigated by the previous mentioned calorimetric techniques.

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

    PubMed

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

    2006-09-01

    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

  18. Serum uric acid: not a discriminator of coronary heart disease in men and women.

    PubMed

    Allard, C; Goulet, C

    1973-11-17

    Fasting serum uric acid (SUA) was measured using a spectrophotometric method in 635 randomized male subjects aged 20 to 70, as part of an epidemiological study carried our among the civil employees of French origin working for the City of Montreal. It was observed that SUA was not age-dependent and that the overall mean value was 6.26 mg./100 ml. On the other hand SUA was studied in 742 males and 260 females, all of whom had had coronarography. A significant difference in SUA between males and females of 1.26 mg./100 ml. was noted. Correlating the SUA levels with the incidence of CHD or the severity of the lesions in the coronary arteries indicated no relationship between CHD and SUA concentrations in men or in women. The results of this study permit the conclusion that SUA is not a discriminator for CHD. PMID:4758870

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

    PubMed Central

    Wang, Jiajia; Tan, Xijuan; Song, Zhenghua

    2013-01-01

    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

  20. Fructose and Uric Acid: Is There a Role in Endothelial Function?

    PubMed Central

    Jia, Guanghong; Aroor, Annayya R.; Whaley-Connell, Adam T.; Sowers, James R.

    2014-01-01

    Population level data support that consumption of fructose and fructose-based sweeteners has dramatically increased and suggest that high dietary intake of fructose is an important factor in the development of the cardiorenal metabolic syndrome (CRS). The CRS is a constellation of cardiac, kidney and metabolic disorders including insulin resistance, obesity, metabolic dyslipidemia, high blood pressure, and evidence of early cardiac and kidney disease. The consequences of fructose metabolism may result in intracellular ATP depletion, increased uric acid production, oxidative stress, inflammation, and increased lipogenesis, which are associated with endothelial dysfunction. Endothelial dysfunction is an early manifestation of vascular disease and a driver for the development of CRS. A better understanding of fructose overconsumption in the development of CRS may provide new insights into pathogenesis and future therapeutic strategies. PMID:24760443

  1. Effects of low birth weight in 8- to 13-year-old children: implications in endothelial function and uric acid levels.

    PubMed

    Franco, Maria C P; Christofalo, Dejaldo M J; Sawaya, Ana Lydia; Ajzen, Sérgio A; Sesso, Ricardo

    2006-07-01

    Low birth weight has been associated with an increased incidence of adult cardiovascular disease. Endothelial dysfunction and high levels of serum uric acid are associated with hypertension. In this study, we have determined whether uric acid is related to blood pressure and vascular function in children with low birth weight. We evaluated vascular function using high-resolution ultrasound, blood pressure, and uric acid levels in 78 children (35 girls, 43 boys, aged 8 to 13 years). Increasing levels of uric acid and systolic blood pressure were observed in children with low birth weight. Birth weight was inversely associated with both systolic blood pressure and uric acid; on the other hand, uric acid levels were directly correlated with systolic blood pressure in children of the entire cohort. Low birth weight was associated with reduced flow-mediated dilation (r=0.427, P<0.001). Because the children with low birth weight had elevated uric acid as well as higher systolic blood pressure levels, we evaluated the correlation between these variables. In the low birth weight group, multiple regression analysis revealed that uric acid (beta=-2.886; SE=1.393; P=0.040) had a graded inverse relationship with flow-mediated dilation, which was not affected in a model adjusting for race and gender. We conclude that children with a history of low birth weight show impaired endothelial function and increased blood pressure and uric acid levels. These findings may be early expressions of vascular compromise, contributing to susceptibility to disease in adult life. PMID:16682609

  2. Serum Uric Acid Concentrations in Meat Eaters, Fish Eaters, Vegetarians and Vegans: A Cross-Sectional Analysis in the EPIC-Oxford Cohort

    PubMed Central

    Schmidt, Julie A.; Crowe, Francesca L.; Appleby, Paul N.; Key, Timothy J.; Travis, Ruth C.

    2013-01-01

    Introduction Circulating concentrations of uric acid may be affected by dietary components such as meat, fish and dairy products, but only a few studies have compared uric acid concentrations among individuals who exclude some or all of these foods from their diet. The aim of this study was to investigate differences in serum uric acid concentrations between meat eaters, fish eaters, vegetarians and vegans. Subjects and Methods A sample of 670 men and 1,023 women (424 meat eaters, 425 fish eaters, 422 vegetarians and 422 vegans, matched on age and sex) from the European Prospective Investigation into Cancer and Nutrition Oxford cohort were included in this cross-sectional analysis. Diet was assessed using a semi-quantitative food frequency questionnaire and serum concentrations of uric acid were measured. Mean concentrations of uric acid by diet group were calculated after adjusting for age, body mass index, calcium and alcohol intake. Results In both men and women, serum uric acid concentrations differed significantly by diet group (p<0.0001 and p?=?0.01, respectively). The differences between diet groups were most pronounced in men; vegans had the highest concentration (340, 95% confidence interval 329–351 µmol/l), followed by meat eaters (315, 306–324 µmol/l), fish eaters (309, 300–318 µmol/l) and vegetarians (303, 294–312 µmol/l). In women, serum uric acid concentrations were slightly higher in vegans (241, 234–247 µmol/l) than in meat eaters (237, 231–242 µmol/l) and lower in vegetarians (230, 224–236 µmol/l) and fish eaters (227, 221–233 µmol/l). Conclusion Individuals consuming a vegan diet had the highest serum concentrations of uric acid compared to meat eaters, fish eaters and vegetarians, especially in men. Vegetarians and individuals who eat fish but not meat had the lowest concentrations of serum uric acid. PMID:23418557

  3. Endogenous and Uric Acid-Induced Activation of NLRP3 Inflammasome in Pregnant Women with Preeclampsia

    PubMed Central

    Matias, Mariana Leticia; Romăo, Mariana; Weel, Ingrid Cristina; Ribeiro, Vanessa Rocha; Nunes, Priscila Rezeck; Borges, Vera Therezinha; Araújo, Joăo Pessoa; Peraçoli, José Carlos; de Oliveira, Leandro; Peraçoli, Maria Terezinha

    2015-01-01

    Preeclampsia (PE) is a specific syndrome of pregnancy, characterized by hypertension and proteinuria. This pathology is associated with hyperuricemia and elevated serum levels of inflammatory cytokines. Uric acid crystals may activate an intracellular complex called inflammasome, which is important for processing and release of inflammatory cytokines. This study investigated the state of monocyte activation, both endogenous and stimulated with monosodium urate (MSU), by gene expression of NLRP1 and NLRP3 receptors as well as their association with inflammatory cytokines expression. Monocytes were obtained from peripheral blood of 23 preeclamptic pregnant women, 23 normotensive pregnant women (NT) and 23 healthy non-pregnant women (NP). Inflammasome activation was evaluated by the gene expression of NLRP1, NLRP3, caspase-1, IL-1?, IL-18 and TNF-? by RT-qPCR in unstimulated monocytes (endogenous expression), or after cell stimulation with MSU (stimulated expression). The concentration of cytokines was assessed by ELISA. In preeclamptic pregnant women, gene expression of NLRP1, NLRP3, caspase-1, IL-1? and TNF-? by monocytes stimulated or not with MSU was significantly higher than in NT and NP groups. Stimulation of monocytes from preeclamptic and non-pregnant women with MSU induced increased gene expression of NLRP3, caspase-1 and TNF-? in relation to the endogenous expression in these groups, while this was not observed in the NT group. The cytokine determination showed that monocytes from women with PE produced higher endogenous levels of IL-1?, IL-18 and TNF-? compared to the other groups, while the stimulus with MSU led to higher production of these cytokines in preeclamptic group than in the NT group. In conclusion, the results showed increased basal gene expression of NLRP1 and NLRP3 receptors in monocytes from PE group. These cells stimulation with MSU demonstrates that uric acid plays a role in NLRP3 inflammasome activation, suggesting the participation of this inflammatory complex in the pathogenesis of preeclampsia. PMID:26053021

  4. Ammonia volatilization from a flooded rice field fertilized with amended urea materials

    Microsoft Academic Search

    H. S. Chauhan; B. Mishra

    1989-01-01

    The extent of ammonia volatilization from prilled urea, urea supergranule and urea amended with neem seed cake, shell-lac and dicyandiamide was studied in a field experiment on flooded rice. The ammonia loss was measured by the closed acid trap method. The collected ammonia was highest from unamended prilled urea, accounting for 19 to 20 per cent of the applied N

  5. Urea Metabolism in Beef Steers Fed Tall Fescue, Orchardgrass, or Gamagrass Hays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two experiments were conducted to assess effects of endophyte treatments (Exp. 1), forage species, and supplementation (Exp. 2) on urea production, excretion, and recycling in beef steers. Infusion of 15,15N-urea and enrichment of urea in urine samples were used to calculate urea N entry and recyc...

  6. Correcting Nitrogen Deficiencies in Cotton with Urea-Based Products

    E-print Network

    Livingston, Stephen; Stichler, Charles

    1995-11-22

    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....

  7. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...PAPERBOARD COMPONENTS Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium...a component of articles intended for use in producing, manufacturing,...

  8. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...PAPERBOARD COMPONENTS Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium...a component of articles intended for use in producing, manufacturing,...

  9. Hydrogen production via urea electrolysis using a gel electrolyte

    NASA Astrophysics Data System (ADS)

    King, Rebecca L.; Botte, Gerardine G.

    2011-03-01

    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.

  10. Correcting Nitrogen Deficiencies in Cotton with Urea-Based Products 

    E-print Network

    Livingston, Stephen; Stichler, Charles

    1995-11-22

    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....

  11. Formation of urea and guanidine by irradiation of ammonium cyanide.

    NASA Technical Reports Server (NTRS)

    Lohrmann, R.

    1972-01-01

    Aqueous solutions of ammonium cyanide yield urea, cyanamide and guanidine when exposed to sunlight or an unfiltered 254 nm ultraviolet source. The prebiotic significance of these results is discussed.

  12. Physics based modeling of urea selective catalytic reduction systems

    E-print Network

    Na, Hanbee

    2010-01-01

    This thesis addresses control-oriented modeling of urea-selective catalytic reduction (SCR) after-treatment systems used for reducing NO, emission in diesel vehicles. Starting from first-principles, appropriate simplifications ...

  13. Materials for thermohydrolysis of urea in a fluidized bed

    Microsoft Academic Search

    O. Kröcher; M. Elsener

    2009-01-01

    The production of ammonia from urea was investigated in a fluidized bed reactor in order to avoid the formation of N2O in the selective non-catalytic reduction (SNCR) process, which occurs when urea is directly injected into an SNCR reactor.Among about 20 tested materials, ?-Al2O3 proved to be the best suited as a fluidized bed material due to its high catalytic

  14. Detoxication of Ammonia in Sheep Fed Soy Protein or Urea

    Microsoft Academic Search

    WILLIAM CHALUPA; JIMMY CLARK; PAMELA OPLIGER

    Urea-fed sheep were able to detoxify additional ammonia absorbed from the digestive tract by a mechanism involving increased concentrations of liver ornithine. Feeding urea as the sole nitrogen source caused decreases in activities of carbamyl phosphate synthetase, ornithine transcarbamylase and argĂĽĂ­ase while no differences were noted in activities of arginine synthetase and argininosuccinase. Decreases in these enzyme systems were concluded

  15. Urea-requiring lactate dehydrogenases of marine elasmobranch fishes

    Microsoft Academic Search

    Paul H. Yancey; George N. Somero

    1978-01-01

    The kinetic properties — apparentKm of pyruvate, pyruvate inhibition pattern, and maximal velocity — of M4 (skeletal muscle) lactate dehydrogenases of marine elasmobranch fishes resemble those of the homologous lactate dehydrogenases of non-elasmobranchs only when physiological concentrations of urea (approximately 400 mM) are present in the assay medium. Urea increases the apparentKm of pyruvate to values typical of other vertebrates

  16. Pulsatile urea excretion in the gulf toadfish: mechanisms and controls

    Microsoft Academic Search

    Chris M. Wood; M. Danielle McDonald; Lena Sundin; Pierre Laurent; Patrick J. Walsh

    2003-01-01

    Opsanus beta expresses a full complement of ornithine–urea cycle (OUC) enzymes and is facultatively ureotelic, reducing ammonia-N excretion and maintaining urea-N excretion under conditions of crowding\\/confinement. The switch to ureotelism is keyed by a modest rise in cortisol associated with a substantial increase in cytosolic glutamine synthetase for trapping of ammonia-N and an upregulation of the capacity of the mitochondrial

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

    Microsoft Academic Search

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

    2004-01-01

    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

  18. In vitro metabolism of creatinine, methylamine and amino acids by intestinal contents of normal and uraemic subjects

    Microsoft Academic Search

    C W Owens; Z P Albuquerque; G M Tomlinson

    1979-01-01

    An original method which uses in vitro anaerobic incubation at 37 degrees C followed by centrifugation, ultrafiltration, and ion exchange chromatography is described; it shows that faecal material suspended in physiological saline can destroy added creatinine. The rate of breakdown by suspensions from uraemic subjects (mean 780 mumol h-1kg-1 SEM 70) was slightly faster than in normal subjects (mean 550

  19. Extract of Rhodiola rosea Radix Reduces the Level of C-Reactive Protein and Creatinine Kinase in the Blood

    Microsoft Academic Search

    M. Abidov; S. Grachev; R. D. Seifulla; T. N. Ziegenfuss

    2004-01-01

    The effects of extracts of Rhodiola rosea radix on blood levels of inflammatory C-reactive protein and creatinine kinase were studied in healthy untrained volunteers before and after exhausting exercise. Rhodiola rosea extract exhibited an antiinflammatory effect and protected muscle tissue during exercise.

  20. Correlation between creatinine clearance and Helicobacter pylori infection eradication with sequential and triple therapeutic regimens: A randomised clinical trial

    Microsoft Academic Search

    Mohammadreza Seyyedmajidi; Kianoosh Falaknazi; Dariush Mirsattari; Homayoun Zojaji; Mohammad Roshani; Farhad Lahmi; Peyman Gooran Orimi; Maryam Hadizadeh; Mohammadreza Zali

    2011-01-01

    Background and study aimsUraemic patients show susceptibility to gastrointestinal mucosal lesions and colonisation by Helicobacter pylori (HP). Antibiotic resistance constitutes a problem in treatment and bismuth preparations are toxic in uraemic patients. This study aimed to assess the correlation between creatinine clearance (CrCl) and eradication of HP infection with new sequential and standard triple therapeutic regimens.

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

    PubMed

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

    2015-02-01

    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

  2. Taste modulating N-(1-methyl-4-oxoimidazolidin-2-ylidene) ?-amino acids formed from creatinine and reducing carbohydrates.

    PubMed

    Kunert, Christof; Walker, Alesia; Hofmann, Thomas

    2011-08-10

    Recent investigations led to the discovery of N-(1-methyl-4-oxoimidazolidin-2-ylidene)aminopropionic acid as a taste modulator enhancing the typical thick-sour mouthdryness and mouthfulness imparted by stewed beef juice. In the present study, systematic model reactions were targeted toward the generation of a series of N-(1-methyl-4-oxoimidazolidin-2-ylidene)-?-amino acids by Maillard-type reactions between creatinine and ribose, glucose, methylglyoxal, or glyoxal, respectively. By application of a comparative taste dilution analysis on fractions isolated from thermally treated creatinine/carbohydrate mixtures by means of hydrophilic liquid interaction chromatography (HILIC), a total of nine N-(1-methyl-4-oxoimidazolidin-2-ylidene)-?-amino acids were identified by means of LC-MS, LC-TOF-MS, and 1D/2D NMR experiments. Six of the nine creatinine glycation products were previously not reported in the literature. Whereas creatinine exhibited a bitter taste, none of the N-(1-methyl-4-oxoimidazolidin-2-ylidene)-?-amino acids imparted any intrinsic taste activity up to levels of 10 mmol/L (in water). Depending strongly on their chemical structure, these N-(1-methyl-4-oxoimidazolidin-2-ylidene)-?-amino acids induced a thick-sour, mouthdrying orosensation and mouthfulness enhancement when evaluated in model broth with recognition thresholds ranging from 31 to >1000 ?mol/L. PMID:21702476

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

    PubMed

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

    2013-05-01

    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

  4. Association of blood lipids, creatinine, albumin, and CRP with socioeconomic status in Malawi

    PubMed Central

    2013-01-01

    Background The objective of these analyses is to document the relationship between biomarker-based indicators of health and socioeconomic status (SES) in a low-income African population where the cumulative effects of exposure to multiple stressors on physiological functions and health in general are expected to be highly detrimental for the well-being of individuals. Methods Biomarkers were collected subsequent to the 2008 round of the Malawi Longitudinal Study of Families and Health (MLSFH), a population-based study in rural Malawi, including blood lipids (total cholesterol, LDL, HDL, ratio of total cholesterol to HDL), biomarkers of renal and liver organ function (albumin and creatinine) and wide-range C-reactive protein (CRP) as a non-specific biomarker for inflammation. These biomarkers represent widely used indicators of health that are individually or cumulatively recognized as risk factors for age-related diseases among prime-aged and elderly individuals. Quantile regressions are used to estimate the age-gradient and the within-day variation of each biomarker distribution. Differences in biomarker levels by socioeconomic status are investigated using descriptive and multivariate statistics. Results Overall, the number of significant associations between the biomarkers and socioeconomic measures is very modest. None of the biomarkers significantly varies with schooling. Except for CRP where being married is weakly associated with lower risk of having an elevated CRP level, marriage is not associated with the biomarkers measured in the MLSFH. Similarly, being Muslim is associated with a lower risk of having elevated CRP but otherwise religion does not predict being in the high-risk quartiles of any of the MLSFH biomarkers. Wealth does not predict being in the high-risk quartile of any of the MLSFH biomarkers, with the exception of a weak effect on creatinine. Being overweight or obese is associated with increased likelihood of being in the high-risk quartile for cholesterol, Chol/HDL ratio, and LDL. Conclusions The results provide only weak evidence for variation of the biomarkers by socioeconomic indicators in a poor Malawian context. Our findings underscore the need for further research to understand the determinants of health outcomes in a poor low-income context such as rural Malawi. PMID:23448548

  5. EVALUATION OF UREA FERTILIZERS AND UREASE INHIBITORS FOR CORN AND WHEAT PRODUCTION (PHOSPHOROAMIDE, HYDROLYSIS)

    Microsoft Academic Search

    ALAN JAY SCHLEGEL

    1985-01-01

    Urea is the major solid N fertilizer in world agriculture, however, ammonia volatilization from surface-applied urea fertilizers can result in urea producing lower crop yields than other N fertilizers. Urease inhibitors retard urea hydrolysis and, in laboratory studies, reduce ammonia volatilization loss from urea fertilizers.^ Six phosphoroamide urease inhibitors trichloroethyl phosphorodiamidate, diethyl phosphoric triamide, dimethyl phosphoric triamide, N-(diaminophosphinyl)-cyclohexylamine, N-benzyl-N-methyl phosphoric

  6. Evaluation of the urinary cortisol: creatinine ratio in the diagnosis of hyperadrenocorticism in dogs.

    PubMed

    Jensen, A L; Iversen, L; Koch, J; Hřier, R; Petersen, T K

    1997-03-01

    The diagnostic accuracy of the urinary cortisol:creatinine ratio (CCR), with the cortisol being measured by ELISA, was evaluated by subjecting data from 18 dogs with and 20 dogs without hyperadrenocorticism to receiver operating characteristic (ROC) curve analysis. The area under the ROC curve (W 0.93, SE(w) 0.044) was much higher than 0.5, indicating that the CCR did distinguish between dogs with and without hyperadrenocorticism. A cutoff value of about 60 x 10(-6) was associated with the highest sensitivity (1.0) and specificity (0.85). At the disease prevalence rate of the present study (0.47), the positive and negative predictive values were 0.87 and 1.0, respectively. These numbers indicate that canine hyperadrenocorticism may be safely excluded when the CCR is below 60 x 10(-6) but that a test of higher specificity (eg, the ACTH stimulation test) should be used to confirm the diagnosis of canine hyperadrenocorticism when the CCR is above 60 x 10(-6). PMID:9097240

  7. The effect of hibiscus sabdariffa on lipid profile, creatinine, and serum electrolytes: a randomized clinical trial.

    PubMed

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

    2011-01-01

    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

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

    PubMed Central

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

    2011-01-01

    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

  9. Catalyzed Decomposition of Urea. Molecular Dynamics Simulations of the Binding of Urea to Urease

    PubMed Central

    Estiu, Guillermina; Merz, Kenneth M.

    2008-01-01

    We present the results of molecular dynamics simulations on the urea/urease system. The starting structure was prepared from the 2.0Ĺ crystal structure of Benini et al. of DAP-inhibited urease (PDB code 3UBP),1 and the trimeric structure (2479 residues) resulted in 180K atoms after solvation by water. The force field parameters were derived using the bonded model approach described by Hoops et al.2 Three different systems were analyzed, each one modeling a different protonation pattern for the His320 and His219 residues. In each case, the three monomers of urease have been analyzed separately. The time averaged structures observed in the three monomers suggest that urease could follow two different competitive mechanisms. A “protein assisted proton transfer” mechanism points to Asp221 as crucial for catalysis. An “Asp mediated proton transfer” involves the transfer of a proton from the bridging OH to a NH2 moiety of urea, assisted by Asp360 in the active site. The impact of the simulation results on our understanding of urease catalysis are discussed in detail. PMID:16584179

  10. Pulsatile urea excretion in the gulf toadfish: mechanisms and controls.

    PubMed

    Wood, Chris M; McDonald, M Danielle; Sundin, Lena; Laurent, Pierre; Walsh, Patrick J

    2003-12-01

    Opsanus beta expresses a full complement of ornithine-urea cycle (OUC) enzymes and is facultatively ureotelic, reducing ammonia-N excretion and maintaining urea-N excretion under conditions of crowding/confinement. The switch to ureotelism is keyed by a modest rise in cortisol associated with a substantial increase in cytosolic glutamine synthetase for trapping of ammonia-N and an upregulation of the capacity of the mitochondrial OUC to use glutamine-N. The entire day's urea-N production is excreted in 1 or 2 short-lasting pulses, which occur exclusively through the gills. The pulse event is not triggered by an internal urea-N threshold, is not due to pulsatile urea-N production, but reflects pulsatile activation of a specific branchial excretion mechanism that rapidly clears urea-N from the body fluids. A bidirectional facilitated diffusion transporter, with pharmacological similarity to the UT-A type transporters of the mammalian kidney, is activated in the gills, associated with an increased trafficking of dense-cored vesicles in the pavement cells. An 1814 kB cDNA ('tUT') coding for a 475-amino acid protein with approximately 62% homology to mammalian UT-A's has been cloned and facilitates phloretin-sensitive urea transport when expressed in Xenopus oocytes. tUT occurs only in gill tissue, but tUT mRNA levels do not change over the pulse cycle, suggesting that tUT regulation occurs at a level beyond mRNA. Circulating cortisol levels consistently decline prior to a pulse event and rise thereafter. When cortisol is experimentally clamped at high levels, natural pulse events are suppressed in size but not in frequency, an effect mediated through glucocorticoid receptors. The cortisol decline appears to be permissive, rather than the actual trigger of the pulse event. Fluctuations in circulating AVT levels do not correlate with pulses; and injections of AVT (at supraphysiological levels) elicit only minute urea-N pulses. However, circulating 5-hydroxytryptamine (5-HT) levels fluctuate considerably and physiological doses of 5-HT cause large urea-N pulse events. When the efferent cranial nerves to the gills are sectioned, natural urea pulse events persist, suggesting that direct motor output from the CNS to the gill is not the proximate control. PMID:14662293

  11. Recycling of polyurethane-urea RIM

    SciTech Connect

    Xiao, H.X.; Kresta, J.E.; Suthar, B.; Li, X.H. [Univ. of Detroit, Mercy, MI (United States)

    1997-12-31

    Polyurethane-urea (PUU) RIM are crosslinked materials, which cannot be reprocessed or recycled by using the conventional process. The chemical decrosslinking reaction or transesterification of themosetting polyurethanes by using various inorganic and organic catalysts were investigated. The recycling of waste PUU RIM materials (unpainted, painted and filler reinforced) through decrosslinking (transesterification) using low molecular weight glycols in presence of catalyst was evaluated. It was established that the transestification of PUU RIM can be carried out at the low glycol (EG)/RIM ratio (15/84.5) and that the usual recovery step for the excess glycol (EG) can be avoided resulting in an economical process. The process was scaled up in a 50 gallon reactor at the LymTal International Inc. successfully. It was established that the products from the decrosslinking of PUU RIM are a mixture of the liquid oligomers (LOs) containing urethane, OH and NH{sub 2} groups. These functional groups in LOs exhibit many potential applications as raw materials in the preparation of RIM coatings, adhesives, foams, sealants and composites. PUU RIM made from LOs exhibited promising and interesting results. Both solvent-based and waterborne urethane coatings could be made from LOs. Urethane adhesives made from LOs showed improvement of properties with increasing amounts of LOs. Structural adhesives based on epoxy and LOs were prepared and the effects of equivalent ratios and curing conditions on the adhesive strength of the epoxy/LO adhesives were investigated. Solvent-free coating based on epoxy and LOs was prepared and their properties were determined. Both wood fiber and glass fabric reinforced composites were prepared by using epoxy and LOs and they exhibited interesting properties for different potential applications.

  12. Salvage of blood urea nitrogen in sheep is highly dependent on plasma urea concentration and the efficiency of capture within the diegestive tract

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective was to establish the relationships between transfer of blood urea-N to the digestive tract (GIT) and utilisation of recycled urea-N within the GIT, and to determine which of these two mechanisms of the urea recycling process places greater limits on N salvage by growing sheep. Four gro...

  13. NHEXAS PHASE I MARYLAND STUDY--STANDARD OPERATING PROCEDURE FOR COLLECTION, STORAGE, AND SHIPMENT OF URINE SAMPLES FOR METAL, PESTICIDE, AND CREATININE ANALYSIS (F10)

    EPA Science Inventory

    The purpose of this SOP is to describe the procedures for collection, storage, and shipment of urine samples for metal, pesticides, and creatinine analysis. Samples were collected on Days 2 and 8 of each Cycle. The Day 2 sample was analyzed for metals and creatinine. The Day 8...

  14. 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

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

    2000-01-01

    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

  15. Uric Acid Lowering to Prevent Kidney Function Loss in Diabetes: The Preventing Early Renal Function Loss (PERL) Allopurinol Study

    PubMed Central

    Maahs, David M.; Caramori, M. Luiza; Cherney, David Z.I.; Galecki, Andrzej T.; Gao, Chuanyun; Jalal, Diana; Perkins, Bruce A.; Pop-Busui, Rodica; Rossing, Peter; Mauer, Michael; Doria, Alessandro

    2013-01-01

    Diabetic kidney disease causes significant morbidity and mortality among people with type 1 diabetes (T1D). Intensive glucose and blood pressure control have thus far failed to adequately curb this problem and therefore a major need for novel treatment approaches exists. Multiple observations link serum uric acid levels to kidney disease development and progression in diabetes and strongly argue that uric acid lowering should be tested as one such novel intervention. A pilot of such a trial, using allopurinol, is currently being conducted by the Preventing Early Renal Function Loss (PERL) Consortium. Although the PERL trial targets T1D individuals at highest risk of kidney function decline, the use of allopurinol as a renoprotective agent may also be relevant to a larger segment of the population with diabetes. As allopurinol is inexpensive and safe, it could be cost-effective even for relatively low-risk patients, pending the completion of appropriate trials at earlier stages. PMID:23649945

  16. Conductimetric biosensor for the detection of uric Acid by immobilization uricase on nata de coco membrane-pt electrode.

    PubMed

    Mulyasuryani, Ani; Srihardiastutie, Arie

    2011-01-01

    A conductimetric enzyme biosensor for uric acid detection has been developed. The uricase, as enzyme, is isolated from Candida utilis and immobilized on a nata de coco membrane-Pt electrode. The biosensor demonstrates a linear response to urate over the concentration range 1-6 ppm and has good selectivity properties. The response is affected by the membrane thickness and pH change in the range 7.5-9.5. The response time is three minutes in aqueous solutions and in human serum samples. Application of the biosensor to the determination of uric acid in human serum gave results that compared favourably with those obtained by medical laboratory. The operational stability of the biosensor was not less than three days and the relative error is smaller than 10%. PMID:21792276

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

    Microsoft Academic Search

    M Czauderna; J Kowalczyk

    1997-01-01

    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).

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

    Microsoft Academic Search

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

    2006-01-01

    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

  19. Common Polymorphisms Influencing Serum Uric Acid Levels Contribute to Susceptibility to Gout, but Not to Coronary Artery Disease

    Microsoft Academic Search

    Klaus Stark; Wibke Reinhard; Martina Grassl; Jeanette Erdmann; Heribert Schunkert; Thomas Illig; Christian Hengstenberg

    2009-01-01

    BackgroundRecently, a large meta-analysis including over 28,000 participants identified nine different loci with association to serum uric acid (UA) levels. Since elevated serum UA levels potentially cause gout and are a possible risk factor for coronary artery disease (CAD) and myocardial infarction (MI), we performed two large case-control association analyses with participants from the German MI Family Study. In the

  20. Improving ammonium and nitrate release from urea using clinoptilolite zeolite and compost produced from agricultural wastes.

    PubMed

    Omar, Latifah; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad

    2015-01-01

    Improper use of urea may cause environmental pollution through NH3 volatilization and NO3 (-) leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4 (+) and NO3 (-) release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4 (+) and NO3 (-) losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4 (+) and NO3 (-) release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3 (-) leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4 (+) retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4 (+) and NO3 (-) release from urea. PMID:25793220

  1. Improving Ammonium and Nitrate Release from Urea Using Clinoptilolite Zeolite and Compost Produced from Agricultural Wastes

    PubMed Central

    Omar, Latifah; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab.

    2015-01-01

    Improper use of urea may cause environmental pollution through NH3 volatilization and NO3? leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4+ and NO3? release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4+ and NO3? losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4+ and NO3? release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3? leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4+ retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4+ and NO3? release from urea. PMID:25793220

  2. Influence of modified forms of urea and nitrogen levels on weed growth and grain yield of lowland rice

    Microsoft Academic Search

    R. Venkitaswamy; S. Subramanian; V. Veerabadran

    1991-01-01

    The growth of weeds and their subsequent reduction of rice yield as affected by N source neem cake coated urea (NCU), dicyandiamide coated urea (DCU), rock phosphate coated urea (RPCU), urea supergranules (USG) and prilled urea (PU) was studied on a clay loam soil at Coimbatore, India. Experiments were conducted in northeast monsoon (NEM) 1981, summer 1982, and southwest monsoon

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

    PubMed

    Eriksson, T; Rustas, B-O

    2014-07-01

    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

  4. Toxicology of urea formaldehyde and polyurethane foam insulation.

    PubMed

    Harris, J C; Rumack, B H; Aldrich, F D

    1981-01-16

    Two types of foam insulation are in wide use. Urea formaldehyde foam is a relatively inexpensive, easily installed, and efficient insulation. Toxicity from this insulation is related to release of free formaldehyde into the home. Mild to incapacitating symptoms have been reported in occupants of urea formaldehyde-insulated homes. Airborne formaldehyde levels frequently have exceeded standards set for occupational exposure. The long-term consequences of such exposure are unknown. Because of publicity over the toxicity of urea formaldehyde foam, many physicians and patients have confused urea formaldehyde and polyurethane foam. Unlike urea formaldehyde, polyurethane foam is fully cured before construction. Toxicity occurs only during manufacture and curing. To date, there have been no reports to our knowledge of toxicity in occupants of polyurethane-insulated homes. However, toxicity caused by pyrolysis products may occur during combustion in homes insulated with either type of insulation. This report details 48 patients in whom complete medical data were obtained out of the first 100 patients contacting the Rocky Mountain Poison Center. PMID:7452848

  5. Novel graphene flowers modified carbon fibers for simultaneous determination of ascorbic acid, dopamine and uric acid.

    PubMed

    Du, Jiao; Yue, Ruirui; Ren, Fangfang; Yao, Zhangquan; Jiang, Fengxing; Yang, Ping; Du, Yukou

    2014-03-15

    A novel and sensitive carbon fiber electrode (CFE) modified by graphene flowers was prepared and used to simultaneously determine ascorbic acid (AA), dopamine (DA) and uric acid (UA). SEM images showed that beautiful and layer-petal graphene flowers homogeneously bloomed on the surface of CFE. Moreover, sharp and obvious oxidation peaks were found at the obtained electrode when compared with CFE and glassy carbon electrode (GCE) for the oxidation of AA, DA and UA. Also, the linear calibration plots for AA, DA and UA were observed, respectively, in the ranges of 45.4-1489.23 ?M, 0.7-45.21 ?M and 3.78-183.87 ?M in the individual detection of each component. By simultaneously changing the concentrations of AA, DA and UA, their oxidation peaks appeared at -0.05 V, 0.16 V and 2.6 V, and the good linear responses ranges were 73.52-2305.53 ?M, 1.36-125.69 ?M and 3.98-371.49 ?M, respectively. In addition, the obtained electrode showed satisfactory results when applied to the determination of AA, DA and UA in urine and serum samples. PMID:24140872

  6. Simultaneous determination of ascorbic acid, dopamine, uric acid, and tryptophan by nanocrystalline ZSM-5 modified electrodes.

    PubMed

    Kaur, Balwinder; Srivastava, Rajendra

    2014-09-01

    Nanocrystalline ZSM-5 was prepared by using propyltriethoxysilane as an additive in the conventional ZSM-5 synthesis composition. Materials were characterized by a complementary combination of X-ray diffraction, nitrogen sorption, and Scanning electron microscopy. Transition metal ion exchanged nanocrystalline ZSM-5 (M-Nano-ZSM-5, where M = Cu2+, Ni2+, Co2+, Fe2+, and Mn2+) modified electrodes were constructed for the simultaneous determination of ascorbic acid (AA), dopamine (DA), uric acid (UA), and tryptophan (Trp). Electrochemical studies were carried out by using cyclic voltammetry, linear sweep voltammetry, and chronoamperometry in buffer solution at pH 3.5. Fe-Nano-ZSM-5 modified electrode exhibited excellent electrocatalytic activity with well-separated oxidation peaks towards AA, DA, UA, and Trp in their simultaneous determination. Among the M-Nano-ZSM-5 and transition metal ion-exchanged ZSM-5 (M-ZSM-5) materials investigated in this study, Fe-Nano-ZSM-5 exhibited the highest catalytic activities towards the oxidation of AA, DA, UA, and Trp with good stability, sensitivity, and selectivity. The analytical performance of this sensor was demonstrated for the simultaneous determination of AA, DA, UA, and Trp in blood serum and UA concentration in urine samples. PMID:25924298

  7. Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene.

    PubMed

    Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia; Lu, Xiaoquan; Zhou, Xibin

    2014-05-01

    A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via ?-? conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA-DA, DA-UA and UA-AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2-12.9 mM, 0.5-110 ?M, and 10-1000 ?M, with the detection limits (S/N=3) of 10.09 ?M, 0.29 ?M and 1.24 ?M, respectively. Furthermore, the modified electrode was investigated for real sample analysis. PMID:24746351

  8. Serum Uric Acid, Alanine Aminotransferase, Hemoglobin and Red Blood Cell Count Levels in Pseudoexfoliation Syndrome

    PubMed Central

    Simavl?, Hüseyin; Bucak, Yasin Yücel; Tosun, Mehmet; Erdurmu?, Mesut

    2015-01-01

    Purpose. The pathogenesis of pseudoexfoliation (PEX), the most common cause of secondary glaucoma, has not been clearly identified, but there is increasing evidence that points out the role of oxidative stress. The aim of this study is to evaluate some of the most commonly used blood parameters, hemoglobin (Hb), red blood cell count (RBC), alanine aminotransferase (ALT), and uric acid (UA) levels, in subjects with PEX. Materials and Methods. This study is performed in a state hospital between November 2011 and December 2012. Retrospective chart review of subjects who underwent cataract surgery was performed. Thirty-one healthy subjects with PEX and 34 healthy subjects without PEX were evaluated. Hb, RBC, ALT, and UA levels were recorded. Student's t-test was used to compare the two groups. Results. The mean age was 73.6 ± 14.1 years in PEX group and 70.1 ± 12.7 in control group (p = 0.293). Hb, RBC, ALT, and UA levels did not show a statistically significant difference among PEX and control groups (p > 0.05 for all). Conclusion. Serum levels of Hb, RBC, ALT, and UA levels were similar in subjects with and without PEX. Further studies are needed to clarify the precise role of Hb, RBC, ALT, and UA in the pathogenesis of PEX.

  9. Uric Acid-Degrading Bacteria in Guts of Termites [Reticulitermes flavipes (Kollar)] †

    PubMed Central

    Potrikus, C. J.; Breznak, John A.

    1980-01-01

    Uricolytic bacteria were present in guts of Reticulitermes flavipes in populations up to 6 × 104 cells per gut. Of 82 strains isolated under strict anaerobic conditions, most were group N Streptococcus sp., Bacteroides termitidis, and Citrobacter sp. All isolates used uric acid (UA) as an energy source anaerobically, but not aerobically, and NH3 was the major nitrogenous product of uricolysis. However, none of the isolates had an absolute requirement for UA. Utilization of heterocyclic compounds other than UA was limited. Fresh termite gut contents also degraded UA anaerobically, as measured by 14CO2 evolution from [2-14C]UA. The magnitude of anaerobic uricolysis [0.67 pmol of UA catabolized/(gut × h)] was entirely consistent with the population density of uricolytic bacteria in situ. Uricolytic gut bacteria may convert UA in situ to products usable by termites for carbon, nitrogen, energy, or all three. This possibility is consistent with the fact that R. flavipes termites from UA, but they do not void the purine in excreta despite the lack of uricase in their tissues. PMID:16345587

  10. Development of a sandwich format, amperometric screen-printed uric acid biosensor for urine analysis.

    PubMed

    Kanyong, P; Pemberton, R M; Jackson, S K; Hart, J P

    2012-09-01

    A screen-printed carbon electrode (SPCE) incorporating the electrocatalyst cobalt phthalocyanine (CoPC), fabricated using a water-based ink formulation, has been investigated as the base transducer for a uric acid biosensor. A sandwich biosensor was fabricated by first depositing cellulose acetate (CA) onto this transducer (CoPC-SPCE), followed by uricase (UOX) and finally a polycarbonate (PC) membrane; this device is designated PC-UOX-CA-CoPC-SPCE. This biosensor was used in conjunction with chronoamperometry to optimize the conditions for the analysis of urine: temperature, 35°C; buffer, pH 9.2; ionic strength, 50 mM; uricase, 0.6 U; incubation time, 180 s. The proposed biosensor was applied to urine from a healthy subject. The precision determined on unspiked urine (n=6) was 5.82%. Urine was fortified with 0.225 mM UA, and the resulting precision and recovery were 4.21 and 97.3%, respectively. The linear working range of the biosensor was found to be 0.015 to 0.25 mM (the former represents the detection limit), and the sensitivity was calculated to be 2.10 ?A/mM. PMID:22705172

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

    PubMed Central

    Kim, Tae-Hyoung; Lee, Jae-Hyeok

    2014-01-01

    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

  12. Role for urea in nitrification by polar marine Archaea

    PubMed Central

    Alonso-Sáez, Laura; Waller, Alison S.; Mende, Daniel R.; Bakker, Kevin; Farnelid, Hanna; Yager, Patricia L.; Lovejoy, Connie; Tremblay, Jean-Éric; Potvin, Marianne; Heinrich, Friederike; Estrada, Marta; Riemann, Lasse; Bork, Peer; Pedrós-Alió, Carlos; Bertilsson, Stefan

    2012-01-01

    Despite the high abundance of Archaea in the global ocean, their metabolism and biogeochemical roles remain largely unresolved. We investigated the population dynamics and metabolic activity of Thaumarchaeota in polar environments, where these microorganisms are particularly abundant and exhibit seasonal growth. Thaumarchaeota were more abundant in deep Arctic and Antarctic waters and grew throughout the winter at surface and deeper Arctic halocline waters. However, in situ single-cell activity measurements revealed a low activity of this group in the uptake of both leucine and bicarbonate (<5% Thaumarchaeota cells active), which is inconsistent with known heterotrophic and autotrophic thaumarchaeal lifestyles. These results suggested the existence of alternative sources of carbon and energy. Our analysis of an environmental metagenome from the Arctic winter revealed that Thaumarchaeota had pathways for ammonia oxidation and, unexpectedly, an abundance of genes involved in urea transport and degradation. Quantitative PCR analysis confirmed that most polar Thaumarchaeota had the potential to oxidize ammonia, and a large fraction of them had urease genes, enabling the use of urea to fuel nitrification. Thaumarchaeota from Arctic deep waters had a higher abundance of urease genes than those near the surface suggesting genetic differences between closely related archaeal populations. In situ measurements of urea uptake and concentration in Arctic waters showed that small-sized prokaryotes incorporated the carbon from urea, and the availability of urea was often higher than that of ammonium. Therefore, the degradation of urea may be a relevant pathway for Thaumarchaeota and other microorganisms exposed to the low-energy conditions of dark polar waters. PMID:23027926

  13. Role for urea in nitrification by polar marine Archaea.

    PubMed

    Alonso-Sáez, Laura; Waller, Alison S; Mende, Daniel R; Bakker, Kevin; Farnelid, Hanna; Yager, Patricia L; Lovejoy, Connie; Tremblay, Jean-Éric; Potvin, Marianne; Heinrich, Friederike; Estrada, Marta; Riemann, Lasse; Bork, Peer; Pedrós-Alió, Carlos; Bertilsson, Stefan

    2012-10-30

    Despite the high abundance of Archaea in the global ocean, their metabolism and biogeochemical roles remain largely unresolved. We investigated the population dynamics and metabolic activity of Thaumarchaeota in polar environments, where these microorganisms are particularly abundant and exhibit seasonal growth. Thaumarchaeota were more abundant in deep Arctic and Antarctic waters and grew throughout the winter at surface and deeper Arctic halocline waters. However, in situ single-cell activity measurements revealed a low activity of this group in the uptake of both leucine and bicarbonate (<5% Thaumarchaeota cells active), which is inconsistent with known heterotrophic and autotrophic thaumarchaeal lifestyles. These results suggested the existence of alternative sources of carbon and energy. Our analysis of an environmental metagenome from the Arctic winter revealed that Thaumarchaeota had pathways for ammonia oxidation and, unexpectedly, an abundance of genes involved in urea transport and degradation. Quantitative PCR analysis confirmed that most polar Thaumarchaeota had the potential to oxidize ammonia, and a large fraction of them had urease genes, enabling the use of urea to fuel nitrification. Thaumarchaeota from Arctic deep waters had a higher abundance of urease genes than those near the surface suggesting genetic differences between closely related archaeal populations. In situ measurements of urea uptake and concentration in Arctic waters showed that small-sized prokaryotes incorporated the carbon from urea, and the availability of urea was often higher than that of ammonium. Therefore, the degradation of urea may be a relevant pathway for Thaumarchaeota and other microorganisms exposed to the low-energy conditions of dark polar waters. PMID:23027926

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

    PubMed

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

    2013-06-01

    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

  15. Effect of the super-flux cellulose triacetate dialyser membrane on the removal of non-protein-bound and protein-bound uraemic solutes

    Microsoft Academic Search

    Rita De Smet; Annemieke Dhondt; Sunny Eloot; Francesco Galli; Marie Anne Waterloos; Raymond Vanholder

    Background. Uraemic solutes accumulate in haemodialysis (HD) patients and interfere with physiological functions. Low-flux (LF) HD does not efficiently remove all uraemic compounds. We investigated whether large pore super-flux (SF) cellulose triacetate membranes (CTA) result in a better removal of uraemic solutes. Methods. Eleven patients were dialysed consecutively with LF-CTA and SF-CTA during 3 weeks. Urea (UR), creatinine (CR), uric

  16. New Cytochrome P-450 Ligands Based on Urea Derivatives

    Microsoft Academic Search

    A. I. Khlebnikov; R. R. Akhmedzhanov; O. I. Naboka; A. A. Bakibaev; M. I. Tartynova; T. P. Novozheeva; A. S. Saratikov

    2005-01-01

    Cytochrome P-450 (CYPIIB1 isoform) ligands were constructed de novo on the basis of QSAR models derived using the frontal polygon (FP) method. The following compounds were designed and synthesized: 2-phenyl-6-benzyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione, N-acetyl-N'-(1-phenylethyl)urea, and (1-phenyl-3-methylbutyl)urea. Their interaction with phenobarbital-induced microsomes isolated from rat liver was studied spectrophotometrically. The dissociation constants Ks of the enzyme - substrate complexes measured are in good agreement

  17. Urea impedimetric biosensor based on polymer degradation onto interdigitated electrodes

    Microsoft Academic Search

    M. Cortina; M. J. Esplandiu; S. Alegret; M. del Valle

    2006-01-01

    The measurement of urea was accomplished with an interdigitated\\u000a electrode by using ac impedance spectroscopy to follow capacitance\\u000a changes, which were produced during enzyme-catalyzed dissolution of a\\u000a polymer coating. The employed coating was the enteric polymer Eudragit\\u000a S-100, on which urease enzyme was immobilized by carbodiimide coupling.\\u000a Urea was determined in the 0.02-2 M range, proving that the combination\\u000a of

  18. What is Milk Urea Nitrogen and How is It Interpreted? Dr. Doo-Hong Min, Extension Forage Specialist, MSU UPES

    E-print Network

    in milk urea nitrogen. Excess concentrations of urea in the blood can affect milk production, reproductive causes of low milk production and fertility. Urea is an indicator of the balance of the rumen system so

  19. Characterization of Organic Anion Transporter 2 (SLC22A7): A Highly Efficient Transporter for Creatinine and Species-Dependent Renal Tubular Expression.

    PubMed

    Shen, Hong; Liu, Tongtong; Morse, Bridget L; Zhao, Yue; Zhang, Yueping; Qiu, Xi; Chen, Cliff; Lewin, Anne C; Wang, Xi-Tao; Liu, Guowen; Christopher, Lisa J; Marathe, Punit; Lai, Yurong

    2015-07-01

    The contribution of organic anion transporter OAT2 (SLC22A7) to the renal tubular secretion of creatinine and its exact localization in the kidney are reportedly controversial. In the present investigation, the transport of creatinine was assessed in human embryonic kidney (HEK) cells that stably expressed human OAT2 (OAT2-HEK) and isolated human renal proximal tubule cells (HRPTCs). The tubular localization of OAT2 in human, monkey, and rat kidney was characterized. The overexpression of OAT2 significantly enhanced the uptake of creatinine in OAT2-HEK cells. Under physiologic conditions (creatinine concentrations of 41.2 and 123.5 µM), the initial rate of OAT2-mediated creatinine transport was approximately 11-, 80-, and 80-fold higher than OCT2, multidrug and toxin extrusion protein (MATE)1, and MATE2K, respectively, resulting in approximately 37-, 1850-, and 80-fold increase of the intrinsic transport clearance when normalized to the transporter protein concentrations. Creatinine intracellular uptake and transcellular transport in HRPTCs were decreased in the presence of 50 µM bromosulfophthalein and 100 µM indomethacin, which inhibited OAT2 more potently than other known creatinine transporters, OCT2 and multidrug and toxin extrusion proteins MATE1 and MATE2K (IC50: 1.3 µM vs. > 100 µM and 2.1 µM vs. > 200 µM for bromosulfophthalein and indomethacin, respectively) Immunohistochemistry analysis showed that OAT2 protein was localized to both basolateral and apical membranes of human and cynomolgus monkey renal proximal tubules, but appeared only on the apical membrane of rat proximal tubules. Collectively, the findings revealed the important role of OAT2 in renal secretion and possible reabsorption of creatinine and suggested a molecular basis for potential species difference in the transporter handling of creatinine. PMID:25904762

  20. Rates and predictors of ACE inhibitor discontinuation subsequent to elevated serum creatinine: a retrospective cohort study

    PubMed Central

    Jackevicius, Cynthia A; Wong, Joyce; Aroustamian, Irina; Gee, Manyee; Mody, Freny Vaghaiwalla

    2014-01-01

    Objectives ACE inhibitors (ACEI) are underutilised despite cardiovascular benefits, in part due to concerns of known transient elevations in serum creatinine (SCr) after initiation. Our objectives were to evaluate rates and predictors of ACEI discontinuation after SCr elevation post-ACEI initiation since limited data are available that examine this issue. Setting Primary and tertiary Veterans healthcare system in Los Angeles, California, USA Participants 3039 outpatients initiating an ACEI with a SCr measured within 6?months prior to and approximately 3?months after initiating an ACEI. Patients were divided into three groups (SCr <1.5, 1.5–2 and >2). Primary and secondary outcome measures Rates and factors associated with ACEI discontinuation subsequent to SCr elevation after ACEI initiation and for patients with baseline SCr >2?mg/dL, the change in SCr associated with chronic use. Predictors were identified using multivariate logistic regression modelling. Results At 3?months follow-up, for those with an increase in SCr, the mean increase post-ACEI initiation was 26%, ranging from ?0.01?mg/dL to 0.42?mg/dL varying according to a level of baseline renal function. ACEI discontinuation was higher in patients with elevated baseline SCr (19/165, 11.5%) compared with those with SCr <1.5 (135/2497, 5.4%), and those with SCr 1.5–2.0 (28/377, 7.4%). Male patients, and those with heart failure were less likely to discontinue ACEI after an elevation of SCr post-ACEI initiation, while those taking non-steroidal anti-inflammatory drugs, diuretics and ?-blockers were more likely to discontinue ACEI. Conclusions SCr increases <30% on average within 3?months of ACEI initiation, with subsequent discontinuation rates varying by baseline SCr. Elevation in SCr was not associated with ACEI discontinuation rates. In patients with SCr >2?mg/dL at baseline, despite an acute increase in SCr after ACEI initiation, chronic ACEI use was associated with a decrease in SCr in most patients. PMID:25232564

  1. Formation of a mutagenic heterocyclic aromatic amine from creatinine in urine of meat eaters and vegetarians.

    PubMed

    Holland, Ricky D; Gehring, Theresa; Taylor, Jason; Lake, Brian G; Gooderham, Nigel J; Turesky, Robert J

    2005-03-01

    Liquid chromatography electrospray ionization mass spectrometry (MS) with a triple quadrupole MS was used to identify known and novel heterocyclic aromatic amines (HAAs) in human urine. The identities of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were confirmed by their product ion spectra. The constant neutral loss scan mode was employed to probe for other analytes in urine that display the transition [M+H]+-->[M+H-CH3*]+*, which is common to HAAs containing an N-methylimidazo moiety, and led to the detection of a previously unreported isomer of 8-MeIQx [Holland, R., et al. (2004) Chem. Res. Toxicol. 17, 1121-1136]. We now report the identification of another novel HAA, 2-amino-1-methylimidazo[4,5-b]quinoline (IQ[4,5-b]), an isomer of the powerful animal carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ). The amounts of IQ[4,5-b] measured in the urine of human volunteers who consumed grilled beef ranged from 15 to 135% of the ingested dose, while the amounts of 8-MeIQx and PhIP excreted in urine were on average <2% of the ingested dose. Base treatment of urine at 70 degrees C increased the concentrations of 8-MeIQx and PhIP by as much as 6-fold, indicating the presence of phase II conjugates; however, the amount of IQ[4,5-b] increased by more than 100-fold. IQ[4,5-b] was also detected in the urine of vegetarians following base hydrolysis. The formation of IQ[4,5-b], but not IQ, 8-MeIQx, or PhIP, also occurred in urine incubated at 37 degrees C. Creatinine and 2-aminobenzaldehyde are likely precursors of IQ[4,5-b]. The detection of IQ[4,5-b] in the urine of both meat eaters and vegetarians suggests that this HAA may be present in nonmeat staples or that IQ[4,5-b] formation may occur endogenously within the urinary bladder or other biological fluids. PMID:15777097

  2. Doubling of serum creatinine as an outcome after renal transplant - pathological evidence of graft biopsy.

    PubMed

    Tsai, Shang-Feng; Shu, Kuo-Hsiung; Ho, Hao-Chung; Chen, Cheng-Hsu; Wu, Ming-Ju; Wen, Mei-Chin

    2013-01-01

    Background Doubling of serum creatinine (DSC) in transplantation has been seen as the end-point of renal function without pathological evidence. We conducted this study to elucidate the relationship between DSC and pathological findings. Material and Methods We conducted a retrospective cohort study to illustrate pathologic changes in patients receiving a kidney biopsy in the previous 5 years with clinicopathological correlations to DSC and proteinuria. Results Of a total of 99 kidney recipients (146 biopsies), results of graft biopsy were as follows: calcineurin inhibitor toxicity (CNI) (38.7%) and rejection (36.9%). Compared to males, females had higher proportions of class I (p=0.003) and class II PRA (p<0.001), and a higher rejection rate (p=0.042), but had the same clinical outcomes as males, like eGFR at follow-up (p=0.882), DSC (p=0.703), and proteinuria (p=0.745).                         Pathological diagnoses and findings were related to proteinuria: glomerulopathy (HR=4.9, p=0.01), AMR (HR=2.5, p=0.025), especially acute AMR (HR=2.9, p=0.008), chronic glomerular change (HR=10.2, p=0.002), arteriolar hyaline (HR=2.3, p=0.026), and mesangial matrix change (HR=6.3, p=0.002).                         BK nephropathy and rejection were the only 2 risk factors. Pathological findings favoring AMR (PTC infiltration and glomerulitis) showed a greater risk of DSC compared with those favoring CMR (interstitial inflammation, intimal arteritis, and tubulitis). DSC was correlated with clinical manifestation (rejection) and provided strong pathological evidence. Conclusions There was more acute rejection and chronic pathological change in women, but outcomes were the same due to less activity of renin-angiotensin-aldosterone and hyperfiltration in females. DSC as an end-point of graft function can be used to identify recipients, especially AMR or mixed AMR and CMR. 1. All forms of support received by each author: None of the authors received support. 2. Any potential conflict of interest for each author: No conflict of interest for any of the authors. PMID:24025693

  3. Random spot urine protein/creatinine ratio: a reliable method for monitoring lupus nephritis?

    PubMed Central

    Guedes Marques, Maria; Cotovio, Patrícia; Ferrer, Francisco; Silva, Cristina; Botelho, Carlos; Lopes, Karina; Maia, Pedro; Carreira, Armando; Campos, Mário

    2013-01-01

    Background Lupus nephritis (LN) is a common and severe manifestation of systemic lupus erythematosus (SLE) that can lead to end-stage renal disease. According to the Kidney Disease Outcomes Global Improving clinical Guidelines for Glomerulonephritis, spot urine protein/creatinine (P/C) ratio should be used for monitoring LN. However, some reports write that the random spot urine P/C ratio is unreliable in monitoring proteinuria in SLE glomerulonephritis patients. The aim of this study was to evaluate the agreement of these two assay methods. Methods The prospective observational study was performed. Fifty-three paired (total 106) spot and 24-h urine collections were evaluated. Statistical analysis: SPSS 20.0. Results Paired samples t-test did not reveal significant differences between the two-paired assay methods (spot P/C ratio versus 24-h proteinuria and 24-h P/C ratio) and a statistically significant correlation was observed between them: Pearson's coefficient of 0.847 (P < 0.001) and 0.863 (P < 0.001), respectively. However, after stratifying by degrees of proteinuria, a poor correlation was found in the range of <500 mg/day and only 26.6% of 24-h P/C ratio was explained by the spot P/C ratio. Adding to this, for proteinuria range between 500 and 1000 mg/day, there was no correlation (Pearson's ?0.098; P > 0.05). In fact, only 1% of 24-h measurements could be explained by the spot P/C ratio. Conclusions Our study demonstrated a good correlation between 24-h proteinuria and random P/C ratio among patients with LN. However, this correlation was poor for proteinuria under 500 mg/day and did not exist in a range between 500 and 1000 mg/day. This finding is of greater importance because this range is quite common in patients with LN remission. Until further clarification, to the best of our knowledge, we maintain reluctant to completely substitute the 24-h collection by the P/C ratio especially when a renal flare is suspected, or before any change in therapy.

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

    PubMed

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

    2015-01-01

    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

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

    PubMed

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

    2015-04-01

    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. PMID:24858040

  6. Nomogram to predict uric acid kidney stones based on patient’s age, BMI and 24-hour urine profiles: A multicentre validation

    PubMed Central

    Torricelli, Fabio Cesar Miranda; Brown, Robert; Berto, Fernanda C.G.; Tarplin, Sarah; Srougi, Miguel; Mazzucchi, Eduardo; Monga, Manoj

    2015-01-01

    Introduction: We performed a multicentre validation of a nomogram to predict uric acid kidney stones in two populations. Methods: We reviewed the kidney stone database of two institutions, searching for patients with kidney stones who had stone composition analysis and 24-hour urine collection from January 2010 to December 2013. A nomogram to predict uric acid kidneys stones based on patient age, body mass index (BMI), and 24-hour urine collection was tested. Receiver-operating curves (ROC) were performed. Results: We identified 445 patients, 355 from Cleveland, United States, and 90 from Sao Paulo, Brazil. Uric acid stone formers were 7.9% and 8.9%, respectively. Uric acid patients had a significantly higher age and BMI, as well as significant lower urinary calcium than calcium stone formers in both populations. Uric acid had significantly higher total points when scored according to the nomogram. ROC curves showed an area under the curve of 0.8 for Cleveland and 0.92 for Sao Paulo. The cutoff value that provided the highest sensitivity and specificity was 179 points and 192 for Cleveland and Sao Paulo, respectively. Using 180 points as a cutoff provided a sensitivity and specificity of 87.5% and 68% for Cleveland, and 100% and 42% for Sao Paulo. Higher cutoffs were associated with higher specificity. The main limitation of this study is that only patients from high volume hospitals with uric acid or calcium stones were included. Conclusion: Predicting uric acid kidneys stone based on a nomogram, which includes only demographic data and 24-hour urine parameters, is feasible with a high degree of accuracy. PMID:26085876

  7. 40 CFR 721.6440 - Polyamine urea-for-malde-hyde condensate (specific name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Polyamine urea-for-malde-hyde condensate (specific name). 721...urea-for-malde-hyde condensate (specific name). ...polyamine ureaformaldehyde condensate (PMN P-87-1456) is...uses are: (i) Release to water. Requirements as...

  8. 40 CFR 721.6440 - Polyamine urea-for-malde-hyde condensate (specific name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Polyamine urea-for-malde-hyde condensate (specific name). 721...urea-for-malde-hyde condensate (specific name). ...polyamine ureaformaldehyde condensate (PMN P-87-1456) is...uses are: (i) Release to water. Requirements as...

  9. 40 CFR 721.6440 - Polyamine urea-for-malde-hyde condensate (specific name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Polyamine urea-for-malde-hyde condensate (specific name). 721...urea-for-malde-hyde condensate (specific name). ...polyamine ureaformaldehyde condensate (PMN P-87-1456) is...uses are: (i) Release to water. Requirements as...

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

    E-print Network

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

    2009-12-07

    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.

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

    E-print Network

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

    2009-01-01

    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.

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

    PubMed Central

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

    2009-01-01

    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

  13. 77 FR 42273 - Solid Urea From the Russian Federation: Preliminary Results of Antidumping Duty Administrative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-18

    ...Initiation of Antidumping and Countervailing Duty Administrative Reviews and Requests for Revocation...See Solid Urea From the Russian Federation: Extension...See Solid Urea from the Russian Federation: Final Results...explaining that price and quantity are not...

  14. 76 FR 35405 - Solid Urea From the Russian Federation: Preliminary Results of Antidumping Duty Administrative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-17

    ...Initiation of Antidumping and Countervailing Duty Administrative Reviews and Deferral of Initiation...See Solid Urea From the Russian Federation: Extension...exists between EuroChem and its franchisees. For...Solid Urea from the Russian...

  15. catena-Poly[[[bis­(thio­urea-?S)copper(I)]-?-thio­urea-?2 S:S] iodide acetonitrile hemisolvate

    PubMed Central

    Jia, Li; Kong, Ling-Qian; Li, Da-Cheng

    2008-01-01

    The title complex, {[Cu(CH4N2S)3]I·0.5CH3CN}n, was formed by the reaction of CuI and thio­urea in acetonitrile. There are two independent CuI ions in the asymmetric unit which are coordinated by two terminal and two bridging thio­urea ligands to form a one-dimensional helical chain structure progagating in the a-axis direction. Each CuI ion is in a distorted tetra­hedral coordination environment. The crystal structure is stabilized by weak N—H?S and N—H?I hydrogen bonds. PMID:21202021

  16. Association of plasma manganese levels with chronic renal failure.

    PubMed

    Sánchez-González, Cristina; López-Chaves, Carlos; Gómez-Aracena, Jorge; Galindo, Pilar; Aranda, Pilar; Llopis, Juan

    2015-07-01

    Manganese (Mn) is an essential trace element involved in the formation of bone and in amino acid, lipid and carbohydrate metabolism. Mn excess may be neurotoxic to humans, affecting specific areas of the central nervous system. However, relatively little is known about its physiological and/or toxicological effects, and very few data are available concerning the role of Mn in chronic renal failure (CRF). This paper describes a 12-month study of the evolution of plasma Mn levels in predialysis patients with CRF and the relationship with energy and macronutrient intake. The participants in this trial were 64 patients with CRF in predialysis and 62 healthy controls. Plasma levels of creatinine, urea, uric acid, total protein and Mn were measured. The glomerular filtration rate (GFR) was calculated using the Cockcroft-Gault index. The CRF patients had higher plasma levels of creatinine, urea, uric acid and Mn and a lower GFR than the controls. Plasma Mn was positively correlated with creatinine, plasma urea and plasma uric acid and was negatively correlated with the GFR and the intake of energy and macronutrients. In conclusion, CRF in predialysis patients is associated with increases in circulating levels of Mn. PMID:26004896

  17. Regulation of urea permeability in frog urinary bladder by prostaglandin E 2

    Microsoft Academic Search

    Vera T. Bachteeva; Ekaterina M. Fock; Elena A. Lavrova; Elena V. Naboka; Rimma G. Parnova

    2002-01-01

    The present study was performed to investigate the role of prostaglandin E2 (PGE2) in the regulation of urea transport in the frog urinary bladder, which is known to occur via a specialized arginine-vasotocin- (AVT-) regulated urea transporter. The bladders isolated from Rana temporaria L. were filled with amphibian Ringer solution containing 370 Bq\\/ml (0.01 µCi\\/ml) of [14C]urea, and urea permeability

  18. Curing of urea-formaldehyde adhesives with collagen type hydrolysates under acid condition

    Microsoft Academic Search

    F. Langmaier; J. Šivarová; K. Kolomazník; M. Mládek

    2004-01-01

    Condensation of dimethylol urea and its mixtures with urea or hydrolysate of chrome-tanned leather waste (mass fraction in\\u000a mixture 0.05) in the presence of a variable quantity of phthalic acid, as acid curing agent (within mass fraction limits 0.01-0.1),\\u000a was studied through TG technique. During condensation of sole dimethylol urea or of its mixture with urea, oxy-methylene as\\u000a well as

  19. Irritant and protective action of urea-urease ammonia in rat gastric mucosa

    Microsoft Academic Search

    Joji Takeuchi; Tomohisa Ohuchi; Hiroyuki Harada; Susumu Okabe

    1995-01-01

    The effects of urea-urease-ammonia on the rat gastric mucosa were examined and compared with those of NH4OH and NH4Cl. The mucosal application of urea with urease produced a reduction in potential difference (PD) in a dose-related manner for urea, and a significant drop was observed by >0.1% urea in the presence of 100 units urease. Such PD reduction was also

  20. Glass fiber reinforced composites of phenolic–urea–epoxy resin blends

    Microsoft Academic Search

    M. M. Raj; L. M. Raj; P. N. Dave

    The present work aims to modify conventional epoxy resin by blending with four different phenolic–urea oligomers. These oligomers are similar to phenolic–urea resin matrix and simultaneously function as amino curing agent for epoxy matrix. In this context, phenolic–urea oligomers were prepared respectively by polycondensation reaction of four phenols namely phenol, m-cresol, resorcinol and 1,5-dihydroxy naphthalene, respectively with formaldehyde and urea

  1. Neuro-Fuzzy System for Post-Dialysis Urea Rebound Prediction

    Microsoft Academic Search

    A. T. Azar; A. H. Kandil; K. M. Wahba; A. M. Elgarhy; W. A. Massoud

    2008-01-01

    Measuring post dialysis urea rebound (PDUR) requires a 30- or 60-minute post-dialysis sampling, which is inconvenient. This paper presents a novel technique for predicting equilibrated urea concentration and post dialysis urea rebound in the form of a Takagi-Sugeno-Kang fuzzy inference system. The advantage of this neuro-fuzzy hybrid approach is that it doesn't require 30-60-minute post-dialysis urea sample. Adaptive neuro-fuzzy inference

  2. Refolding of urea-induced denaturation of model proteins by trimethylamine N-oxide

    Microsoft Academic Search

    Pankaj Attri; Pannuru Venkatesu

    2011-01-01

    The biomolecules are known to be stabilized by osmolytes, trimethylamine-N-oxide (TMAO) while urea, destabilizes the protein structures. The deleterious effect of urea on proteins has been counteracted by TMAO is well understood; nonetheless, refolding of urea-induced conformational changes of proteins by TMAO is still an active subject. To understand the refolding ability of TMAO from urea-induced denaturation of biomolecules, we

  3. The Associations of Uric Acid, Cardiovascular and All-Cause Mortality in Peritoneal Dialysis Patients

    PubMed Central

    Dong, Jie; Han, Qing-Feng; Zhu, Tong-Ying; Ren, Ye-Ping; Chen, Jiang-Hua; Zhao, Hui-Ping; Chen, Meng-Hua; Xu, Rong; Wang, Yue; Hao, Chuan-Ming; Zhang, Rui; Zhang, Xiao-Hui; Wang, Mei; Tian, Na; Wang, Hai-Yan

    2014-01-01

    Aims To investigate whether uric acid (UA) is an independent predictor of cardiovascular (CV) and all-cause mortality in peritoneal dialysis (PD) patients after controlling for recognized CV risk factors. Methods A total of 2264 patients on chronic PD were collected from seven centers affiliated with the Socioeconomic Status on the Outcome of Peritoneal Dialysis (SSOP) Study. All demographic and laboratory data were recorded at baseline. Multivariate Cox regression was used to calculate the hazard ratio (HR) of CV and all-cause mortality with adjustments for recognized traditional and uremia-related CV factors. Results There were no significant differences in baseline characteristics between patients with (n?=?2193) and without (n?=?71) UA measured. Each 1 mg/dL of increase in UA was associated with higher all-cause mortality with 1.05(1.00?1.10) of HR and higher CV mortality with 1.12 (1.05?1.20) of HR after adjusting for age, gender and center size. The highest gender-specific tertile of UA predicted higher all-cause mortality with 1.23(1.00?1.52) of HR and higher CV mortality with 1.69 (1.21?2.38) of HR after adjusting for age, gender and center size. The predictive value of UA was stronger in patients younger than 65 years without CV disease or diabetes at baseline. The prognostic value of UA as both continuous and categorical variable weakened or disappeared after further adjusted for uremia-related and traditional CV risk factors. Conclusions The prognostic value of UA in CV and all-cause mortality was weak in PD patients generally, which was confounded by uremia-related and traditional CV risk factors. PMID:24416142

  4. Uric acid is a strong independent predictor of renal dysfunction in patients with rheumatoid arthritis

    PubMed Central

    Daoussis, Dimitrios; Panoulas, Vasileios; Toms, Tracey; John, Holly; Antonopoulos, Ioannis; Nightingale, Peter; Douglas, Karen MJ; Klocke, Rainer; Kitas, George D

    2009-01-01

    Introduction Recent evidence suggests that uric acid (UA), regardless of crystal deposition, may play a direct pathogenic role in renal disease. We have shown that UA is an independent predictor of hypertension and cardiovascular disease (CVD), and that CVD risk factors associate with renal dysfunction, in patients with rheumatoid arthritis (RA). In this study we investigated whether UA associates with renal dysfunction in patients with RA and whether such an association is independent or mediated through other comorbidities or risk factors for renal impairment. Methods Renal function was assessed in 350 consecutive RA patients by estimated glomerular filtration rate (GFR) using the six-variable Modification of Diet in Renal Disease equation. Risk factors for renal dysfunction were recorded or measured in all participants. Linear regression was used to test the independence of the association between GFR and UA. Results Univariable analysis revealed significant associations between GFR and age, systolic blood pressure, total cholesterol, triglycerides, RA duration and UA. UA had the most powerful association with renal dysfunction (r = -0.45, P < 0.001). A basic model was created, incorporating all of the above parameters along with body mass index and gender. UA ranked as the first correlate of GFR (P < 0.001) followed by age. Adjustments for the use of medications (diuretics, low-dose aspirin, cyclooxygenase II inhibitors and nonsteroidal anti-inflammatory drugs) and further adjustment for markers of inflammation and insulin resistance did not change the results. Conclusions UA is a strong correlate of renal dysfunction in RA patients. Further studies are needed to address the exact causes and clinical implications of this new finding. RA patients with elevated UA may require screening for renal dysfunction and appropriate management. PMID:19630964

  5. Serum Uric Acid Predicts Both Current and Future Components of the Metabolic Syndrome

    PubMed Central

    Osgood, Kristy; Krakoff, Jonathan

    2013-01-01

    Abstract Background Uric acid (UA) is known to be associated with excess adiposity and insulin resistance. Our aim was to investigate the relationship between UA and the factors associated with the metabolic syndrome and type 2 diabetes mellitus (T2DM), both initially and longitudinally. Methods Serum UA was assessed as a potential determinant of concurrent blood pressure, serum lipids, glucose regulation measured via an oral glucose tolerance test (OGTT), acute insulin response (AIR), and insulin action (M) measured with hyperinsulinemic–euglycemic clamps in 245 participants (72% Native American, 56% male). UA was also assessed as a predictor of the above variables in 60 participants with follow-up data available (median follow-up time=11.2 years [interquartile range (IQR)=8.1, 13.6 years]. The impact of UA on the risk of T2DM was determined as 36 of the 245 participants developed T2DM after the baseline visit. Results UA was negatively associated with both concurrent and future M, such that for every 1?mg/dL increase in serum UA, M decreased 7.6% (P<0.001) and future M decreased 6.3% (P=0.02). However, UA was not associated with AIR (P=0.7). UA concentrations were a predictor of T2DM [hazard risk ratio (HRR)=1.5; P=0.02]. UA was positively associated with both concurrent blood pressure and lipids and also predicted future increases in blood pressure and total cholesterol. Conclusions Not only did UA associate with concomitant insulin action, blood pressure, and lipids, it also predicted future declines in insulin action and T2DM. UA is a potential target for preventing decreases in insulin sensitivity and rises in blood pressure and cholesterol. PMID:23360433

  6. Noncrystalline uric acid inhibits proteoglycan and glycosaminoglycan synthesis in distal tubular epithelial cells (MDCK).

    PubMed

    Borges, F T; Dalboni, M A; Michelacci, Y M; Schor, N

    2010-10-01

    Hyperuricemia is associated with renal stones, not only consisting of uric acid (UrAc) but also of calcium oxalate (CaOx). Glycosaminoglycans (GAGs) are well-known inhibitors of growth and aggregation of CaOx crystals. We analyzed the effect of noncrystalline UrAc on GAG synthesis in tubular distal cells. MDCK (Madin-Darby canine kidney) cells were exposed to noncrystalline UrAc (80 µg/mL) for 24 h. GAGs were labeled metabolically and characterized by agarose gel electrophoresis. The expression of proteoglycans and cyclooxygenase 2 (COX-2) was assessed by real-time PCR. Necrosis, apoptosis and prostaglandin E2 (PGE2) were determined by acridine orange, HOESCHT 33346, and ELISA, respectively. CaOx crystal endocytosis was evaluated by flow cytometry. Noncrystalline UrAc significantly decreased the synthesis and secretion of heparan sulfate into the culture medium (UrAc: 2127 ± 377; control: 4447 ± 730 cpm) and decreased the expression of perlecan core protein (UrAc: 0.61 ± 0.13; control: 1.07 ± 0.16 arbitrary units), but not versican. Noncrystalline UrAc did not induce necrosis or apoptosis, but significantly increased COX-2 and PGE2 production. The effects of noncrystalline UrAc on GAG synthesis could not be attributed to inflammatory actions because lipopolysaccharide, as the positive control, did not have the same effect. CaOx was significantly endocytosed by MDCK cells, but this endocytosis was inhibited by exposure to noncrystalline UrAc (control: 674.6 ± 4.6, CaOx: 724.2 ± 4.2, and UrAc + CaOx: 688.6 ± 5.4 geometric mean), perhaps allowing interaction with CaOx crystals. Our results indicate that UrAc decreases GAG synthesis in MDCK cells and this effect could be related to the formation of UrAc and CaOx stones. PMID:20878016

  7. Multiple organic anion transporters contribute to net renal excretion of uric acid

    PubMed Central

    Eraly, Satish A.; Vallon, Volker; Rieg, Timo; Gangoiti, Jon A.; Wikoff, William R.; Siuzdak, Gary; Barshop, Bruce A.; Nigam, Sanjay K.

    2010-01-01

    Excretion of uric acid, a compound of considerable medical importance, is largely determined by the balance between renal secretion and reabsorption. The latter process has been suggested to be principally mediated by urate transporter 1 (URAT1; slc22a12), but the role of various putative urate transporters has been much debated. We have characterized urate handling in mice null for RST, the murine ortholog of URAT1, as well as in those null for the related organic anion transporters Oat1 and Oat3. Expression of mRNA of other putative urate transporters (UAT, MRP2, MRP4, Oatv1) was unaffected in the knockouts, as were general indexes of renal function (glomerular filtration rate, fractional excretion of fluid and electrolytes). While mass spectrometric analyses of urine and plasma revealed significantly diminished renal reabsorption of urate in RST-null mice, the bulk of reabsorption, surprisingly, was preserved. Oat1- and Oat3-null mice manifested decreased secretion rather than reabsorption, indicating that these related transporters transport urate in the “opposite” direction to RST. Moreover, metabolomic analyses revealed significant alteration in the concentration of several molecules in the plasma and urine of RST knockouts, some of which may represent additional substrates of RST. The results suggest that RST, Oat1, and Oat3 each contribute to urate handling, but, at least in mice, the bulk of reabsorption is mediated by a transporter(s) that remains to be identified. We discuss the data in the context of recent human genetic studies that suggest that the magnitude of the contribution of URAT1 to urate reabsorption might vary with ethnic background. PMID:18270321

  8. Use of Two Sulfonyl Urea Herbicides in Lowbush Blueberry

    Microsoft Academic Search

    Klaus I. N. Jensen; Eric G. Specht

    2004-01-01

    The continuous use of the broad spectrum herbicide hexazinone since 1981 has resulted in many changes to the weedy flora of lowbush blueberry fields, including shifts to hexazinone-tolerant species. Many of these occur in patches and could best be controlled by selective, foliar herbicide treatments. Preliminary assessments of several sufonyl urea (SU) herbicides indicated that tribenuron (Spartan or Express 75%

  9. Growth and evaluation of some urea derivative crystals

    Microsoft Academic Search

    M Ardoino; L Zeng; C Razzetti; M Zha; L Zanotti; M Curti

    2000-01-01

    Looking for compounds with optical properties comparable or better than those of urea we have performed crystallization tests on phenylurea, 1,1-dimethylurea and 1,3-dimethylurea. Appreciable results have been obtained for 1,3-dimethylurea grown by the normal freezing method. The ingots display good keeping and mechanical properties. Phase matching has been achieved with an encouraging doubling efficiency.

  10. In situ poly(urea-formaldehyde) microencapsulation of dicyclopentadiene

    E-print Network

    Sottos, Nancy R.

    material are required for self-healing materials. Urea-formaldehyde microcapsules containing a mechanical trigger for the self-healing process when damage occurs in the host material and the capsules rupture. The key feature of self-healing materials is the highly engineered microencapsulated healing

  11. Prebiotic formation of polyamino acids in molten urea

    NASA Astrophysics Data System (ADS)

    Mita, H.; Nomoto, S.; Terasaki, M.; Shimoyama, A.; Yamamoto, Y.

    2005-04-01

    It is important for research into the origins of life to elucidate polyamino acid formation under prebiotic conditions. Only a limited set of amino acids has been reported to polymerize thermally. In this paper we demonstrate a novel thermal polymerization mechanism in a molten urea of alkylamino acids (i.e. glycine, alanine, ?-alanine, ?-aminobutyric acid, valine, norvaline, leucine and norleucine), which had been thought to be incapable of undergoing thermal polymerization. Also, aspartic acid was found to polymerize in molten urea at a lower temperature than that at which aspartic acid alone had previously been thermally polymerized. Individual oligomers produced in heating experiments on urea-amino acid mixtures were analysed using a liquid chromatograph mass spectrometer. Major products in the reaction mixture were three different types of polyamino acid derivatives: N-carbamoylpolyamino acids, polyamino acids containing a hydantoin ring at the N-terminal position and unidentified derivatives with molecular weights that were greater by 78 than those of the corresponding peptide forms. The polymerization reaction occurred by taking advantage of the high polarity of molten urea as well as its dehydrating ability. Under the presumed prebiotic conditions employed here, many types of amino acids were thus revealed to undergo thermal polymerization.

  12. ANTIMICROBIAL ACTIVITIES OF N-CHLORAMINES AND DIAZOLIDINYL UREA

    EPA Science Inventory

    A combination of MICs of an N-chloramine, a simple chlorinated amino acid, and diazolidinyl urea gave synergistic activity against bacteria, but not fungi. The two compounds at a higher concentration, 0.1 and 0.3%, respectively, gave synergistic inhibition of fungi; kill times we...

  13. Using urea to decompose polylactic acid in bark compost

    Microsoft Academic Search

    Kenji Nakamura

    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

  14. NEW QUATERNARY AMMONIUM ION REAGENTS FROM UREA FOR FABRIC TREATMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recently, we showed a one step conversion of urea to tertiary amines in water (J. Org. Chem., 2000, 65, 9234-9237). Of these, we used triallylamine to quaternize PEG, PPG, and aryl bromides (Figure 1). One and two-dimensional NMR and chemical ionization mass spectrometries were used to characteriz...

  15. Corrosion testing of urea-formaldehyde foam insulating material

    Microsoft Academic Search

    R. Weil; A. Graviano; K. Sheppard

    1980-01-01

    Two tests of the corrosiveness of urea-formaldehyde (UF) foam insulating materials were compared. One test, the Timm test, had test coupons foamed in place. In the second, the Canadian test, blocks of foam already set were placed in contact with test coupons. The Timm test uses 10 gage thick coupons, while the Canadian test specifies 3 mil thick ones. Two

  16. Effect of alternative pathway therapy on branched chain amino acid metabolism in urea cycle disorder patients

    Microsoft Academic Search

    Fernando Scaglia; Susan Carter; William E O’Brien; Brendan Lee

    2004-01-01

    Urea cycle disorders (UCDs) are a group of inborn errors of hepatic metabolism caused by the loss of enzymatic activities that mediate the transfer of nitrogen from ammonia to urea. These disorders often result in life-threatening hyperammonemia and hyperglutaminemia. A combination of sodium phenylbutyrate and sodium phenylacetate\\/benzoate is used in the clinical management of children with urea cycle defects as

  17. Relationships Between Urea Dilution Measurements and Body Weight and Composition of Lactating Dairy Cows

    Microsoft Academic Search

    R. E. Agnew; T. Yan; W. J. McCaughey; J. D. McEvoy; D. C. Patterson; M. G. Porter; R. W. J. Steen

    2005-01-01

    The objective of the present study was to investigate the potential of the urea dilution technique, coupled with live animal measures to predict the body compo- nents of dairy cattle. The study involved 104 lactating Holstein-Friesian cows offered grass silage-based diets. Urea space volume (USV) was calculated from 2 collec- tion periods of blood samples following infusion of urea at

  18. Use of natural and biobased materials for controlled-release of urea in water: Environmental applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Urea pearls were encapsulated in cloisite-based matrices using different natural materials (lignin, beeswax and latex) to control the release of urea over time. It was found that all cloisite-based fertilizer tablets showed better release profiles than neat urea tablets. The best release profile was...

  19. Inhibition of Smooth Muscle Proliferation by Urea-Based Alkanoic Acids via Peroxisome Proliferator-Activated

    E-print Network

    Hammock, Bruce D.

    Inhibition of Smooth Muscle Proliferation by Urea-Based Alkanoic Acids via Peroxisome Proliferator cell proliferation. We examined the possibility that urea-based alkanoic acids activate the nuclear--These results show that attenuation of smooth muscle cell proliferation by urea-based alkanoic acids is mediated

  20. Role of urea in the postprandial urine concentration cycle of the insectivorous bat Antrozous pallidus.

    PubMed

    Bassett, John E

    2004-02-01

    Insectivorous bats, which feed once daily, produce maximally concentrated urine only after feeding. The role of urea as an osmolyte in this process was investigated in pallid bats (Antrozous pallidus) in the laboratory. Following a 24-h fast, plasma and urine were sampled before and 2 h after feeding in postprandial (PP) animals and before and 2 h after similar treatment without feeding in nonfed (NF) animals. Food consumption by PP animals and handling of NF animals had no effect on blood water content as measured by hematocrit and plasma oncotic pressure. Food consumption increased both plasma osmolality (P(osm)) and plasma urea (P(urea)) by as much as 15%. Food consumption also increased urine osmolality (U(osm)) and urine urea (U(urea)) by 50-100%. Feeding increased U(osm) regardless of changes in P(osm), and elevation of U(osm) resulted primarily from increased U(urea). In NF bats, P(osm) and P(urea) were unchanged, while U(osm) and U(urea) increased by as much as 25%. Again, increased U(osm) resulted primarily from increased U(urea). The PP urine concentration cycle of pallid bats resulted from increased urea excretion in response to apparent rapid urea synthesis. Bats rapidly metabolized protein and excreted urea following feeding when body water was most plentiful. PMID:15123201

  1. Allophanate hydrolase of Oleomonas sagaranensis involved in an ATP-dependent degradation pathway specific to urea

    Microsoft Academic Search

    Takeshi Kanamori; Norihisa Kanou; Shingo Kusakabe; Haruyuki Atomi; Tadayuki Imanaka

    2005-01-01

    The first prokaryotic urea carboxylase has previously been purified and characterized from Oleomonas sagaranensis. As the results indicated the presence of an ATP-dependent urea degradation pathway in Bacteria, the characterization of the second component of this pathway, allophanate hydrolase, was carried out. The gene encoding allophanate hydrolase was found adjacent to the urea carboxylase gene. The purified, recombinant enzyme exhibited

  2. 75 FR 78243 - Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-15

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

  3. Effects of Urea Infusion on the Uterine Luminal Environment of Dairy Cows

    Microsoft Academic Search

    M. L. Rhoads; R. O. Gilbert; M. C. Lucy; W. R. Butler

    2004-01-01

    Previous research indicates that high plasma urea nitrogen (PUN) concentrations are associated with de- creased fertility in lactating dairy cows. The objective of this study was to monitor changes in the uterine environment during acute elevation of PUN. Lactating dairy cows (n = 8) were infused with saline or urea (0.01 g of urea\\/h per kg of body weight) through

  4. Fate and surface transport of urea in a coastal plain soil: a rainfall simulation study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The surface transport of urea has rarely been studied since it is assumed to undergo rapid hydrolysis to ammonia. However, studies have shown urea to exist in estuarine and coastal waters. Urea in small amounts can trigger the diatom Pseudo-nitzschia spp. to produce the toxin domoic acid, which is o...

  5. 75 FR 51440 - Solid Urea from the Russian Federation: Final Results of Antidumping Duty Administrative Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-20

    ...solid urea from the Russian Federation. The...review was produced and exported by MCC...in the ``Issues and Decision Memorandum...Solid Urea from the Russian Federation for the...solid urea from the Russian Federation produced and exported by...

  6. Crystal Structure of Urea Carboxylase Provides Insights into the Carboxyltransfer Reaction*S

    E-print Network

    Tong, Liang

    , fungi, algae, and bacteria possess an enzymatic activity that converts urea to ammonium, enabling them in many bacteria, algae, and fungi and catalyzes the conversion of urea to allophanate, an essential step. In the digestive tracts of many ani- mals, the residing microbes utilize urea from the host to pro- duce biomass

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

    E-print Network

    Paris-Sud XI, Université de

    Urea cycling and ammonia absorption in vivo in the digestive tract of the rat C. DEMIGNÉ C. RÉMÉSY. 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

  8. Protective effect of iridoid glycosides from Paederia scandens (LOUR.) MERRILL (Rubiaceae) on uric acid nephropathy rats induced by yeast and potassium oxonate.

    PubMed

    Hou, Shi-xiang; Zhu, Wen-jing; Pang, Ming-qun; Jeffry, Joseph; Zhou, Lan-lan

    2014-02-01

    Iridoid glycosides of Paederia scandens (IGPS) are an active component isolated from Chinese herb P. scandens (LOUR.) MERRILL (Rubiaceae). Uric acid nephropathy (UAN) is caused by excessive uric acid, which results in damage of kidney tissue via urate crystals deposition in the kidneys. This study aimed to investigate the protective effects of IGPS on UAN in rats induced by yeast and potassium oxonate. Treatment groups received different doses of IGPS and allopurinol (AP) daily for 35 days respectively. The results showed that treatment with IGPS significantly prevented the increases of uric acid in serum and the elevation of systolic blood pressure (SBP), attenuated renal tissue injury, improved renal function and reserved the biological activity of NOS-1. IGPS also inhibited the biological activity of TNF-? and TGF-?1, and suppressed the mRNA expressions of TNF-? and TGF-?1 in renal tissue. Taken together, the present and our previous findings suggest that IGPS exerts protective effects against kidney damage in UAN rats through its uric acid-lowering, anti-inflammatory and immunomodulatory properties. Furthermore, decreasing SBP by up regulation of NOS-1 expression and down regulation of TNF-? and TGF-?1 expression are involved in the effect of IGPS on high uric acid-induced nephropathy. PMID:24287205

  9. Comparison of measured glomerular filtration rates with isotope infusion and with the modification of diet in renal disease equation in cancer patients with raised serum creatinine.

    PubMed

    Javaid, Amrah; Jaffri, Saghir Ahmed; Munir, Iqbal; Qazi, Muhammad H; Nawaz, Muhammad Khalid

    2015-03-01

    To compare the measured glomerular filtration rate (rGFR) using [99mTc] diethylene triamine pentacetic acid (DTPA) clearance or estimated GFR (eGFR) by the Modification of Diet in Renal Disease (MDRD) equation in cancer patients with raised serum creatinine level, we studied 100 cancer patients; 50 patients with normal serum creatinine (control group) and 50 patients with abnormal serum creatinine (study group). History of patients, including site of cancer, chemotherapy regime and dose of chemotherapy, was recorded. The rGFR and eGFR were increased in the study group as compared with the control group, but the GFR recorded by the MDRD formula or DTPA revealed similar values. It is therefore concluded that the MDRD equation may be recommended for eGFR estimation even with abnormal creatinine, without the need for exposure to radiation. PMID:25758877

  10. Effects of acute creatine supplementation on iron homeostasis and uric acid-based antioxidant capacity of plasma after wingate test

    PubMed Central

    2012-01-01

    Background Dietary creatine has been largely used as an ergogenic aid to improve strength and athletic performance, especially in short-term and high energy-demanding anaerobic exercise. Recent findings have also suggested a possible antioxidant role for creatine in muscle tissues during exercise. Here we evaluate the effects of a 1-week regimen of 20?g/day creatine supplementation on the plasma antioxidant capacity, free and heme iron content, and uric acid and lipid peroxidation levels of young subjects (23.1?±?5.8?years old) immediately before and 5 and 60?min after the exhaustive Wingate test. Results Maximum anaerobic power was improved by acute creatine supplementation (10.5?%), but it was accompanied by a 2.4-fold increase in pro-oxidant free iron ions in the plasma. However, potential iron-driven oxidative insult was adequately counterbalanced by proportional increases in antioxidant ferric-reducing activity in plasma (FRAP), leading to unaltered lipid peroxidation levels. Interestingly, the FRAP index, found to be highly dependent on uric acid levels in the placebo group, also had an additional contribution from other circulating metabolites in creatine-fed subjects. Conclusions Our data suggest that acute creatine supplementation improved the anaerobic performance of athletes and limited short-term oxidative insults, since creatine-induced iron overload was efficiently circumvented by acquired FRAP capacity attributed to: overproduction of uric acid in energy-depleted muscles (as an end-product of purine metabolism and a powerful iron chelating agent) and inherent antioxidant activity of creatine. PMID:22691230

  11. Final report on CCQM-K80: Comparison of value-assigned CRMs and PT materials: Creatinine in human serum

    NASA Astrophysics Data System (ADS)

    Camara, Johanna E.; Duewer, David L.; Gasca Aragon, Hugo; Lippa, Katrice A.; Toman, Blaza

    2013-01-01

    The 2009 CCQM-K80 'Comparison of value-assigned CRMs and PT materials: creatinine in human serum' is the first in a series of key comparisons directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes. CCQM-K80 compared the assigned serum creatinine values of certified reference materials (CRMs) using measurements made on these materials under repeatability conditions. Six NMIs submitted 17 CRM materials for evaluation, all intended for sale to customers. These materials represent nearly all of the higher-order CRMs then available for this clinically important measurand. The certified creatinine mass fraction in the materials ranged from 3 mg/kg to 57 mg/kg. All materials were stored and prepared according the specifications provided by each NMI. Samples were processed and analyzed under repeatability conditions by one analyst using isotope dilution liquid chromatography-mass spectrometry. The instrumental repeatability imprecision, expressed as a percent relative standard deviation, was 1.2%. Given the number of materials and the time required for each analysis, the measurements were made in two measurement campaigns ('runs'). In both campaigns, replicate analyses (two injections of one preparation separated in time) were made on each of two or three independently prepared aliquots from one randomly selected unit of each of the 17 materials. The mean value, between-campaign, between-aliquot and between-replicate variance components, standard uncertainty of the mean value, and the number of degrees of freedom associated with the standard uncertainty were estimated using a linear mixed model. Since several of the uncertainties estimated using this traditional frequentist approach were associated with a single degree of freedom, Markov Chain Monte Carlo Bayesian analysis was used to estimate 95% level-of-confidence coverage intervals, U95. Uncertainty-weighted generalized distance regression was used to establish the key comparison reference function (KCRF) relating the assigned values to the repeatability measurements. Parametric bootstrap Monte Carlo was used to estimate 95% level-of-confidence coverage intervals for the degrees of equivalence of materials, d +/- U95(d), and of the participating NMIs, D +/- U95(D). Because of the wide range of creatinine mass fraction in the materials, these degrees of equivalence are expressed in percent relative form: %d +/- U95(%d) and %D +/- U95(%D). On the basis of leave-one-out cross-validation, the assigned values for 16 of the 17 materials were deemed equivalent at the 95% level of confidence. These materials were used to define the KCRF. The excluded material was identified as having a marginally underestimated assigned uncertainty, giving it large and potentially anomalous influence on the KCRF. However, this material's %d of 1.4 +/- 1.5 indicates that it is equivalent with the other materials at the 95% level of confidence. The median |%d| for all 17 of the materials is 0.3 with a median U95(%d) of 1.9. All of these higher-order CRMs for creatinine in human serum are equivalent within their assigned uncertainties. The median |%D| for the participating NMIs is 0.3 with a median U95(%D) of 2.1. These results demonstrate that all participating NMIs have the ability to correctly value-assign CRMs and proficiency test materials for creatinine in human serum and similar measurands. 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 CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Elevation of BUN is predictive of long-term mortality in critically ill patients independent of 'normal' creatinine

    PubMed Central

    Beier, Kevin; Eppanapally, Sabitha; Bazick, Heidi S.; Chang, Domingo; Mahadevappa, Karthik; Gibbons, Fiona K.; Christopher, Kenneth B.

    2012-01-01

    Objective We hypothesized that elevated BUN can be associated with all cause mortality independent of creatinine in a heterogeneous critically ill population. Design Multicenter observational study of patients treated in medical and surgical intensive care units. Setting 20 intensive care units in two teaching hospitals in Boston, Massachusetts Patients 26,288 patients, age ? 18 years, hospitalized between 1997 and 2007 with creatinine 0.80–1.30 mg/dl. Measurements BUN at ICU admission was categorized as 10–20, 20–40 and >40 mg/dl. Logistic regression examined death at days 30, 90 and 365 post-ICU admission as well as in hospital mortality. Adjusted odds ratios were estimated by multivariable logistic regression models. Interventions None Key Results BUN at ICU admission is predictive for short term and long term mortality independent of creatinine. 30 days following ICU admission, patients with BUN >40 mg/dl have an Odds Ratio for mortality of 5.12 (95% CI, 4.30–6.09; P<.0001) relative to patients with BUN 10–20 mg/dl. BUN remains a significant predictor of mortality at 30 days following ICU admission following multivariable adjustment for confounders, patients with BUN >40 mg/dl have an Odds Ratio for mortality of 2.78 (95% CI, 2.27–3.39; P<.0001) relative to patients with BUN 10–20 mg/dl. 30 days following ICU admission, patients with BUN 20–40 mg/dl have an OR of 2.15 (95% CI, 1.98–2.33; <.0001) and a multivariable OR of 1.53 (95% CI, 1.40–1.68; P<.0001) relative to patients with BUN 10–20 mg/dl. Results were similar at 90 and 365 days following ICU admission as well as in-hospital mortality. A subanalysis of patients with blood cultures (n= 7,482), demonstrated that BUN at ICU admission was associated with the risk of blood culture positivity. Conclusion Among critically ill patients with Cr 0.8–1.3 mg/dl, an elevated BUN is associated with increased mortality, independent of serum creatinine. PMID:21099426

  13. Chelate effects in sulfate binding by amide/urea-based ligands.

    PubMed

    Jia, Chuandong; Wang, Qi-Qiang; Begum, Rowshan Ara; Day, Victor W; Bowman-James, Kristin

    2015-07-01

    The influence of chelate and mini-chelate effects on sulfate binding was explored for six amide-, amide/amine-, urea-, and urea/amine-based ligands. Two of the urea-based hosts were selective for SO4(2-) in water-mixed DMSO-d6 systems. Results indicated that the mini-chelate effect provided by a single urea group with two NH binding sites appears to provide enhanced binding over two amide groups. Furthermore, additional urea binding sites incorporated into the host framework appeared to overcome to some extent competing hydration effects with increasing water content. PMID:25966663

  14. Urea uptake enhances barrier function and antimicrobial defense in humans by regulating epidermal gene expression

    PubMed Central

    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

    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

  15. Choline chloride/urea as an effective plasticizer for production of cellulose films.

    PubMed

    Wang, Sha; Peng, Xinwen; Zhong, Linxin; Jing, Shuangshuang; Cao, Xuefei; Lu, Fachuang; Sun, Runcang

    2015-03-01

    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

  16. Study of photo-oxidative reactivity of sunscreening agents based on photo-oxidation of uric acid by kinetic Monte Carlo simulation.

    PubMed

    Moradmand Jalali, Hamed; Bashiri, Hadis; Rasa, Hossein

    2015-05-01

    In the present study, the mechanism of free radical production by light-reflective agents in sunscreens (TiO2, ZnO and ZrO2) was obtained by applying kinetic Monte Carlo simulation. The values of the rate constants for each step of the suggested mechanism have been obtained by simulation. The effect of the initial concentration of mineral oxides and uric acid on the rate of uric acid photo-oxidation by irradiation of some sun care agents has been studied. The kinetic Monte Carlo simulation results agree qualitatively with the existing experimental data for the production of free radicals by sun care agents. PMID:25746246

  17. A Comprehensive Software and Database Management System for Glomerular Filtration Rate Estimation by Radionuclide Plasma Sampling and Serum Creatinine Methods.

    PubMed

    Jha, Ashish Kumar

    2015-01-01

    Glomerular filtration rate (GFR) estimation by plasma sampling method is considered as the gold standard. However, this method is not widely used because the complex technique and cumbersome calculations coupled with the lack of availability of user-friendly software. The routinely used Serum Creatinine method (SrCrM) of GFR estimation also requires the use of online calculators which cannot be used without internet access. We have developed user-friendly software "GFR estimation software" which gives the options to estimate GFR by plasma sampling method as well as SrCrM. We have used Microsoft Windows(®) as operating system and Visual Basic 6.0 as the front end and Microsoft Access(®) as database tool to develop this software. We have used Russell's formula for GFR calculation by plasma sampling method. GFR calculations using serum creatinine have been done using MIRD, Cockcroft-Gault method, Schwartz method, and Counahan-Barratt methods. The developed software is performing mathematical calculations correctly and is user-friendly. This software also enables storage and easy retrieval of the raw data, patient's information and calculated GFR for further processing and comparison. This is user-friendly software to calculate the GFR by various plasma sampling method and blood parameter. This software is also a good system for storing the raw and processed data for future analysis. PMID:26097422

  18. The effect of inter-laboratory variability on the protein:creatinine (UPC) ratio in canine urine.

    PubMed

    Rossi, G; Bertazzolo, W; Dondi, F; Binnella, M; Gruarin, M; Scarpa, P; Paltrinieri, S

    2015-04-01

    Quantification of proteinuria is a fundamental step in staging dogs with chronic kidney disease and in monitoring the course of disease or the efficacy of anti-proteinuric treatments. Analytical precision and accuracy of the proteinuria assessment could be affected by several factors such as biological variability, different operators and quality control materials. The aim of this study was to assess whether inter-laboratory variability could affect the urinary protein to creatinine (UPC) ratio and whether this variability may affect patient classification according to the International Renal Interest Society (IRIS) sub-staging system. The same urine samples were analysed in three different laboratories using different instruments and different reagent brands. The results of the three laboratories were highly correlated to each other although urinary protein (UP), urinary creatinine (UC) and the UPC ratio of one laboratory were found to be significantly higher than those of the other two. No significant differences between the other two laboratories were recorded. The concordance in classifying dogs according to the IRIS guidelines was good if all three proteinuria categories were analysed separately or if borderline proteinuric (BP) dogs were included in the proteinuric group, and very good if BP dogs were merged into the non-proteinuric group. The inter-laboratory variability in UPC ratio measurement was not so great as to impede the identification of proteinuric dogs, but may influence the estimation of the magnitude of proteinuria. PMID:25744805

  19. A Comprehensive Software and Database Management System for Glomerular Filtration Rate Estimation by Radionuclide Plasma Sampling and Serum Creatinine Methods

    PubMed Central

    Jha, Ashish Kumar

    2015-01-01

    Glomerular filtration rate (GFR) estimation by plasma sampling method is considered as the gold standard. However, this method is not widely used because the complex technique and cumbersome calculations coupled with the lack of availability of user-friendly software. The routinely used Serum Creatinine method (SrCrM) of GFR estimation also requires the use of online calculators which cannot be used without internet access. We have developed user-friendly software “GFR estimation software” which gives the options to estimate GFR by plasma sampling method as well as SrCrM. We have used Microsoft Windows® as operating system and Visual Basic 6.0 as the front end and Microsoft Access® as database tool to develop this software. We have used Russell's formula for GFR calculation by plasma sampling method. GFR calculations using serum creatinine have been done using MIRD, Cockcroft-Gault method, Schwartz method, and Counahan-Barratt methods. The developed software is performing mathematical calculations correctly and is user-friendly. This software also enables storage and easy retrieval of the raw data, patient's information and calculated GFR for further processing and comparison. This is user-friendly software to calculate the GFR by various plasma sampling method and blood parameter. This software is also a good system for storing the raw and processed data for future analysis.

  20. Enhancement of urea, ammonia and carbon dioxide removal from industrial wastewater using a cascade of hydrolyser–desorber loops

    Microsoft Academic Search

    M. R. Rahimpour; H. R. Mottaghi; M. M. Barmaki

    2010-01-01

    In this study, removal of urea, ammonia and carbon dioxide from wastewater of conventional urea plant in both high and low concentration (ppm scale) levels using a cascade of hydrolyser–desorber loops has been investigated. In conventional urea plants, wastewater treatment sections including co-current configuration of hydrolyser were designed according to the old environmental standards. Nevertheless, the amounts of urea and

  1. Oxidative balance, homocysteine, and uric acid levels in older patients with Late Onset Alzheimer's Disease or Vascular Dementia.

    PubMed

    Cervellati, Carlo; Romani, Arianna; Seripa, Davide; Cremonini, Eleonora; Bosi, Cristina; Magon, Stefania; Passaro, Angelina; Bergamini, Carlo M; Pilotto, Alberto; Zuliani, Giovanni

    2014-02-15

    This study aimed to investigate whether Late Onset Alzheimer's Disease (LOAD) and Vascular Dementia (VAD) might be associated with a distinct profile of oxidative stress (OxS) peripheral markers. Serum levels of hydroperoxides, homocysteine, advanced oxidation protein products, uric acid, thiols, and total and residual antioxidant power were assessed in 103 mild cognitive impairment (MCI), 89 LOAD, 54 VAD patients and 48 Controls. Compared with Controls, a similar oxidative unbalance (high hydroperoxides and low residual antioxidant power) was observed in MCI, LOAD and, although less pronounced, VAD. Moreover, individuals with simultaneously high levels of homocysteine and uric acid, both well-known risk factors for cardiovascular disease, had a high probability to be affected by VAD (O.R.:10.50; 95% C.I.: 2.33-47.2), but not LOAD (O.R.: 3.0; 95% C.I.:0.86-10.76) compared with individuals with normal values. Our data suggest that, although they might share a common OxS-related pathogenesis, VAD and LOAD might maintain some distinctive features, with a predominance of "vascular component" in VAD compared with LOAD. PMID:24321755

  2. Accuracy of some routine method used in clinical chemistry as judged by isotope dilution-mass spectrometry

    SciTech Connect

    Bjoerkhem, I.; Bergman, A.; Falk, O.; Kallner, A.; Lantto, O.; Svensson, L.; Akerloef, E.; Blomstrand, R.

    1981-05-01

    Serum from patients was pooled, filtered, dispensed, and frozen. This pooled specimen was used for accuracy control in 64 participating laboratories in Sweden. Mean values (state-of-the-art values) were obtained for creatinine, cholesterol, glucose, urea, uric acid, and cortisol. These values were compared with values obtained with highly accurate reference methods based on isotope dilution-mass spectrometry. Differences were marked in the case of determination of creatinine and cortisol. Concerning the other components, the differences between the state-of-the-art value and the values obtained with the reference methods were negligible. Moreover, the glucose oxidase and the oxime methods for determination of glucose and urea were found to give significantly lower values than the hexokinase and urease methods, respectively. Researchers conclude that methods with a higher degree of accuracy are required for routine determination of creatinine and cortisol.

  3. Model selection for urea kinetics in dialysis therapy

    Microsoft Academic Search

    F. Grandi; G. Avanzolini; A. Cappello; A. Santoro

    1993-01-01

    Single- and doublepi modeh of U- The parameters characterizing Model 1 are the urea kinetics during dialysis therapy are compared on the Production, G,, and the initial total volume, vo while basis of simulated and experimental data. The adopted initial condition is estimated by x(O)=C(O)\\/v,. criterium includes descriptive ability, accuracy of Fig.lb shows the second-order model (Model 2) where parameter

  4. Zinc oxide-chitosan nanobiocomposite for urea sensor

    Microsoft Academic Search

    Pratima R. Solanki; Ajeet Kaushik; Anees A. Ansari; G. Sumana; B. D. Malhotra

    2008-01-01

    Zinc oxide (ZnO)-chitosan (CH) nanobiocomposite film onto indium-tin-oxide (ITO) coated glass has been used to immobilize urease (Urs) and glutamate dehydrogenase (GLDH) for urea detection. The presence of ZnO nanoparticles in CH results in its increased surface area and enhanced electron transfer kinetics. The Urs-GLDH\\/CH-ZnO\\/ITO bioelectrode characterized using electrochemical, Fourier transform infrared, and scanning electron microscopy studies exhibit linearity of

  5. Odor evaluation of fatty methyl esters purified as urea adducts

    Microsoft Academic Search

    G. R. List; R. L. Hoffmann; Helen A. Moser; C. D. Evans

    1967-01-01

    Volatile oxidative cleavage products which are present in distilled fatty methyl esters make them unsuitable starting-materials\\u000a for odor evaluation studies. Sensory evaluation of treated and untreated esters shows that crystallization with urea removes\\u000a undersirable odor constituents which result from autoxidation, metal-catalyzed oxidation, light exposure, and distillation.\\u000a The method is simple and by clathrate formation gives, in high yields, pure fatty

  6. Simple and sensitive determination of urea in serum and urine.

    PubMed

    Orsonneau, J L; Massoubre, C; Cabanes, M; Lustenberger, P

    1992-05-01

    In this method for serum and urinary urea determination, the same reagent is used without predilution of urine samples. The method is based on the pH increase resulting from the ammonia released by urease hydrolysis of urea. o-Cresolphthalein complexone is used to monitor the pH change colorimetrically. Urea concentration and absorbance at 570 nm are linearly related for concentrations as great as 600 mmol/L for urine samples and 100 mmol/L for serum. There are no clinically significant interferences from physiological substances or drugs, and precision and accuracy are excellent (CV approximately 2%, except at very low concentrations in serum; analytical recovery was 99% in urine, 100% in serum). Results by this method (y) and by the Astra method (x) for urine correlated well (y = 0.991x - 2.87, Sy/x = 9.21, r = 0.994), as did the results by this method and by the total enzymatic method (x') for serum (y = 1.002x' + 0.192, Sy/x' = 0.598, r = 0.997). This method is applicable to automated as well as manual instruments, and one-reagent or two-reagent formats can be used. PMID:1582010

  7. Manometric biosensor for on-line measurement of milk urea.

    PubMed

    Jenkins, Daniel M; Delwiche, Michael J

    2002-06-01

    Performance of a prototype sensor for on-line measurement of urea in milk during milking was evaluated. The sensor was based on a manometric assay of the carbon dioxide generated by the enzymatic hydrolysis of urea. Temperature compensation of the sensor was described briefly, and was shown to be effective. The calibration of the sensor was described and resulted in a standard calibration error of about 0.15 mM of urea. The standard error of the sensor in milk was shown to be about 0.25 mM (given a physiological range of about 2-7 mM in cow milk). The sensor was simple, inexpensive, suffered from no interferences in raw milk, and completed a measurement cycle in about 5 min (less than the time to milk a typical cow). A custom made sampling device, whereby milk was passively collected from the milk line under vacuum, was shown to collect an ample volume within 10 s to run a test with the sensor. No measurable bubbles or foam were introduced from the sampling mechanism so that the milk sampled was not diminished in density compared to samples taken by other methods. PMID:11959478

  8. Rigid urea and self-healing thiourea ethanolamine monolayers.

    PubMed

    Stefaniu, Cristina; Zaffalon, Pierre-Léonard; Carmine, Alessio; Verolet, Quentin; Fernandez, Samuel; Wesolowski, Tomasz A; Brezesinski, Gerald; Zumbuehl, Andreas

    2015-02-01

    A series of long-tail alkyl ethanolamine analogs containing amide-, urea-, and thiourea moieties was synthesized and the behavior of the corresponding monolayers was assessed on the Langmuir-Pockels trough combined with grazing incidence X-ray diffraction experiments and complemented by computer simulations. All compounds form stable monolayers at the soft air/water interface. The phase behavior is dominated by strong intermolecular headgroup hydrogen bond networks. While the amide analog forms well-defined monolayer structures, the stronger hydrogen bonds in the urea analogs lead to the formation of small three-dimensional crystallites already during spreading due to concentration fluctuations. The hydrogen bonds in the thiourea case form a two-dimensional network, which ruptures temporarily during compression and is recovered in a self-healing process, while in the urea clusters the hydrogen bonds form a more planar framework with gliding planes keeping the structure intact during compression. Because the thiourea analogs are able to self-heal after rupture, such compounds could have interesting properties as tight, ordered, and self-healing monolayers. PMID:25594235

  9. Developing Hypothetical Inhibition Mechanism of Novel Urea Transporter B Inhibitor

    NASA Astrophysics Data System (ADS)

    Li, Min; Tou, Weng Ieong; Zhou, Hong; Li, Fei; Ren, Huiwen; Chen, Calvin Yu-Chian; Yang, Baoxue

    2014-07-01

    Urea transporter B (UT-B) is a membrane channel protein that specifically transports urea. UT-B null mouse exhibited urea selective urine concentrating ability deficiency, which suggests the potential clinical applications of the UT-B inhibitors as novel diuretics. Primary high-throughput virtual screening (HTVS) of 50000 small-molecular drug-like compounds identified 2319 hit compounds. These 2319 compounds were screened by high-throughput screening using an erythrocyte osmotic lysis assay. Based on the pharmacological data, putative UT-B binding sites were identified by structure-based drug design and validated by ligand-based and QSAR model. Additionally, UT-B structural and functional characteristics under inhibitors treated and untreated conditions were simulated by molecular dynamics (MD). As the result, we identified four classes of compounds with UT-B inhibitory activity and predicted a human UT-B model, based on which computative binding sites were identified and validated. A novel potential mechanism of UT-B inhibitory activity was discovered by comparing UT-B from different species. Results suggest residue PHE198 in rat and mouse UT-B might block the inhibitor migration pathway. Inhibitory mechanisms of UT-B inhibitors and the functions of key residues in UT-B were proposed. The binding site analysis provides a structural basis for lead identification and optimization of UT-B inhibitors.

  10. Ammonia and urea excretion in the tidepool sculpin ( Oligocottus maculosus ): sites of excretion, effects of reduced salinity and mechanisms of urea transport

    Microsoft Academic Search

    P. A. Wright; P. Part; C. M. Wood

    1995-01-01

    Tidepool sculpins live in a variable environment where water temperature, salinity, gas tensions, and pH can change considerably with the daily tide cycle. Tidepool sculpins are primarily ammoniotelic, with 8–17% of nitrogen wastes excreted as urea. The majority of net ammonia (Jnetamm; 85%) and urea (Jneturea; 74%) excretion occurred across the gill, with the remainder excreted across the skin, the

  11. Non-enzymatic detection of urea using unmodified gold nanoparticles based aptasensor.

    PubMed

    Kumar, Piyush; Ramulu Lambadi, Paramesh; Kumar Navani, Naveen

    2015-10-15

    Biosensing nitrogenous compounds like urea is required to control the incidents of Economically Motivated Adulteration (EMA). In this study, we report the FluMag Systematic Evolution of Ligands by Exponential Enrichment (FluMag-SELEX) method to isolate a urea specific DNA aptamer with a dissociation constant (Kd) of 232nM. The interaction of DNA aptamer with urea has been confirmed by affinity assay, CD analysis, melting curve analysis and truncation studies. Unlike other urea sensing methods reported so far, using this urea aptamer, we demonstrate a simple, 'non-enzymatic' easy-to-use, dual readout aptasensor that exploits unmodified gold nanoparticles (AuNPs) to transduce the signals of aptamer binding to urea in terms of intrinsic fluorescence differences and color changes simultaneously. This method is free from complicated sample processing and labeling steps. The urea aptasensor displays high selectivity for urea and is free from interference from common milk adulterants. The developed aptasensor reliably detects urea adulteration in milk. The response signals linearly correlate with the increasing concentrations of urea in milk ranging from 20mM to 150mM with detection limit of 20mM. We also show that this aptasensor can also be used as a simple fluorescence based "turn-on" sensor. The results obtained in this study are comparable to the commercial urease based detection methods. PMID:26002019

  12. Cow level sampling factors affecting analysis and interpretation of milk urea concentrations in 2 dairy herds.

    PubMed

    Eicher, R; Bouchard, E; Tremblay, A

    1999-07-01

    The goals of this study were to determine the influence of the variations among udder quarters, the somatic cell count, the time of sampling during the day, sample conservation, and centrifugation on milk urea (UREA) concentrations, and to propose a sample collection procedure for herds that are not on a Dairy Herd Improvement (DHI) program. Forty cows from 2 herds with different feeding practices were randomly selected. The quarter sampled and the somatic cell count did not significantly influence UREA concentrations. Milk urea concentrations were highest in the morning. The diurnal pattern was not influenced by intrinsic factors like parity, days postpartum, or daily milk yield. The UREA concentrations were significantly higher after refrigeration for one week (mean UREA change = +0.41 +/- 0.24 mmol/L, P = 0.0001) and freezing for one month (mean UREA change = +1.52 +/- 1.25 mmol/L, P = 0.0001). Urea concentrations were slightly higher in lactoserum than in whole milk (mean UREA difference = +0.17 +/- 0.24 mmol/L, P = 0.0001). Although this study included only 2 herds and does not allow extrapolation, differences were found in the diurnal pattern of UREA in these 2 herds, which possibly reflect differences in feeding strategy. With consideration of these results, a 6-point sampling procedure for herds that are not on a DHI program is proposed. PMID:10416068

  13. Evaluation of Random Urine Sodium and Potassium Compensated by Creatinine as Possible Alternative Markers for 24 Hours Urinary Sodium and Potassium Excretion

    PubMed Central

    Koo, Hyunmin; Lee, Sang-Guk

    2015-01-01

    Sodium and potassium intake was assessed on the basis of its respective excretion levels in 24 hr urine samples. However, owing to the inconvenience of collection, we evaluated random spot urine for alternative sodium and potassium excretion markers. We included 250 patients who submitted 24 hr- and spot urine for clinical tests. However, 22 patients who showed 24 hr urine creatinine excretion levels <500 mg/day were excluded, because these samples possibly resulted from incomplete urine collection. Moreover, 24 patients were excluded because of their use of diuretics during the urine collection period. We observed significant correlations between 24 hr urine sodium excretion and both the sodium/creatinine (r=0.34, P<0.0001) and the sodium/specific gravity unit (SGU) ratios (r=0.19, P=0.007) in random urine samples. Similarly, 24 hr urine potassium excretion and both the spot urine potassium/creatinine (r=0.47, P<0.0001) and potassium/SGU ratios (r=0.28, P<0.0001) were significantly correlated. Although the estimated sodium/creatinine and potassium/creatinine ratios showed a significant correlation with 24 hr urine sodium and potassium excretion, respectively, further studies are required to develop a spot urine test for individualized monitoring of sodium and potassium excretion. PMID:25729727

  14. Voltammetric detection of uric acid in the presence of ascorbic acid at a gold electrode modified with a self-assembled monolayer of heteroaromatic thiol

    Microsoft Academic Search

    C. Retna Raj; Takeo Ohsaka

    2003-01-01

    Fabrication of a voltammetric sensor based on a self-assembled monolayer (SAM) of a heteroaromatic thiol, mercaptobenzimidazole (MBI) for the determination of uric acid (UA) in the presence of ascorbic acid (AA) is described. The MBI monolayer facilitates the oxidation processes of AA and UA. The orientation of the monolayer on the electrode surface controls the voltammetric behavior of AA and

  15. Use of Contrast-Enhanced Ultrasound to Study Relationship between Serum Uric Acid and Renal Microvascular Perfusion in Diabetic Kidney Disease

    PubMed Central

    Wang, Ling; Cheng, Jia-Fen; Sun, Li-Ping; Song, Ya-Xiang; Xu, Jun-Mei; Wu, Tian-Fu; Mohan, Chandra; Peng, Ai; Liu, Xin-Ying

    2015-01-01

    Purpose. To investigate the relationship between uric acid and renal microvascular perfusion in diabetic kidney disease (DKD) using contrast-enhanced ultrasound (CEUS) method. Materials and Methods. 79 DKD patients and 26 healthy volunteers were enrolled. Renal function and urine protein markers were tested. DKD patients were subdivided into two groups including a normal serum uric acid (SUA) group and a high SUA group. Contrast-enhanced ultrasound (CEUS) was performed, and low acoustic power contrast-specific imaging was used for quantitative analysis. Results. Normal controls (NCs) had the highest levels of AUC, AUC1, and AUC2. Compared to the normal SUA DKD group, high SUA DKD patients had significantly higher IMAX, AUC, and AUC1 (P < 0.05). DKD patients with low urinary uric acid (UUA) excretion had significantly higher AUC2 compared to DKD patients with normal UUA (P < 0.05). Conclusion. Hyperuricemia in DKD patients was associated with a renal ultrasound image suggestive of microvascular hyperperfusion. The CEUS parameter AUC1 holds promise as an indicator for renal microvascular hyperperfusion, while AUC2 might be a useful indicator of declining glomerular filtration rate in DKD patients with decreased excretion of uric acid.

  16. Preparation of selective and sensitive electrochemically treated pencil graphite electrodes for the determination of uric acid in urine and blood serum

    Microsoft Academic Search

    Ali Özcan; Yücel ?ahin

    2010-01-01

    In this study, the preparation of electrochemically treated pencil graphite (ETPG) electrodes in the mixture of lithium perchlorate and sodium carbonate solutions was investigated for the first time in the literature. The prepared ETPG electrodes showed high selectivity and sensitivity for uric acid (UA) oxidation over ascorbic acid and dopamine. Differential pulse voltammetry (DPV) was used as electrochemical method. The

  17. Exercise does not induce major changes in plasma muscle enzymes, creatinine, glucose and total proteins concentrations in untrained beagle dogs.

    PubMed

    Chanoit, G P; Concordet, D; Lefebvre, H P; Orcel, K; Braun, J P

    2002-05-01

    Changes in plasma creatinine (Pl-Creat), glucose, total proteins (Pl-TP), creatine kinase (Pl-CK), lactate dehydrogenase, aspartate aminotransferase and packed cell volume were evaluated in untrained Beagle dogs before, during and after a 60 min race at an average speed of 9 km/h. There was no major effect of exercise on those parameters except, when phases are compared, a slight increase of Pl-TP during exercise (max. + 6.4%), a moderate but after exercise (delayed increase of Pl-CK max. + 245%) and a slight decrease of Pl-Creat after exercise (max. -9.6%). It was therefore concluded that strenuous exercise in sedentary dogs did not induce major variations in any of routine plasma variables measured and would not lead to clinically relevant misinterpretation. However, for Pl-CK, the interpretation of repeated measures may be misleading if two samples are collected in the same animal before and after exercise. PMID:12069266

  18. Feasibility of Discriminating Uric-Acid from Non-Uric-Acid Renal Stones Using Serially Acquired Low- and High-energy CT Scans on a Single-Source CT Scanner

    PubMed Central

    Leng, Shuai; Shiung, Maria; Ai, Songtao; Qu, Mingliang; Vrtiska, Terri J.; Grant, Katharine L.; Krauss, Bernhard; Schmidt, Bernhard; Lieske, John C.; McCollough, Cynthia H.

    2014-01-01

    Objective To demonstrate the feasibility of differentiating uric acid (UA) and non-uric-acid (NUA) renal stones using two consecutive, spatially-registered low- and high-energy scans acquired on a conventional CT system. Materials and Methods A total of 34 patients undergoing clinically indicated dual-source, dual-energy CT exams to differentiate UA and NUA kidney stones were enrolled in this IRB-approved study. Immediately after clinically-indicated dual-source, dual-energy CT and written informed consent, two consecutive scans (one at 80 kV and one at 140 kV) were performed on a conventional CT scanner over the region limited to stones identified on the dual-source scan. After 3D deformable registration of the 80 and 140 kV images, UA and non-UA stones were identified using commercial software. Sensitivity, specificity, and accuracy of stone classification were calculated using the dual-source results as the reference standard. Results A total of 469 stones were identified in dual-source exams (26 UA and 443 NUA). Average in-plane stone diameter was 4.4 ± 2.5 mm (range 2.0 to 18.9 mm). Overall sensitivity, specificity, and accuracy for identifying UA stones were 73%, 90%, and 89%, respectively. The sensitivity, specificity, and accuracy were 95%, 97%, and 97% for stones ?3 mm (n = 341, 19 UA and 322 NUA). Conclusions Accurate differentiation of UA and NUA renal stones is feasible using two consecutively-acquired and spatially-registered conventional CT scans. PMID:25539242

  19. [Use of the Lachema Bio-La-Test for the determination of urea in milk].

    PubMed

    Zelený, J; Síchová, J

    1987-07-01

    The content of urea in milk was studied as a parameter of dairy cow nutrition. It is possible to use for the analysis whole milk where the values are lower by 5.96% than in defatted milk (this fact must be borne in mind when the results are interpreted). Protein can be removed from whole milk within 24 hours after sampling provided that it was placed in a refrigerator within four hours from milking to be stored there at 4 degrees C. In such a case the decrease in urea level is not greater than 4%. No significant differences were found between urea concentration in milk collected by stripping and that in bulk milk. It is not recommended to take samples at the end of milking because such milk contains less urea. Urea concentration in the bulk milk samples corresponds to the average urea concentration in the milk samples taken from dairy cows in the stable. PMID:3116744

  20. Effect of urea addition on giant reed ensilage and subsequent methane production by anaerobic digestion.

    PubMed

    Liu, Shan; Ge, Xumeng; Liew, Lo Niee; Liu, Zhe; Li, Yebo

    2015-09-01

    The effect of urea addition on giant reed ensilage and sequential anaerobic digestion (AD) of the ensiled giant reed was evaluated. The dry matter loss during ensilage (up to 90days) with or without urea addition was about 1%. Addition of 2% urea enhanced production of lactic acid by about 4 times, and reduced production of propionic acid by 2-8 times. Besides, urea addition reduced degradation of cellulose and hemicellulose, and increased degradation of lignin in giant reed during ensilage. Ensilage with or without urea addition had no significant effects on the enzymatic digestibility of giant reed, but ensilage with urea addition achieved a cumulative methane yield of 173L/kgVS, which was 18% higher than that of fresh giant reed. The improved methane yield of giant reed could be attributed to the production of organic acids and ethanol during ensilage. PMID:26094194

  1. Dynamic urea bond for the design of reversible and self-healing polymers

    NASA Astrophysics Data System (ADS)

    Ying, Hanze; Zhang, Yanfeng; Cheng, Jianjun

    2014-02-01

    Polymers bearing dynamic covalent bonds may exhibit dynamic properties, such as self-healing, shape memory and environmental adaptation. However, most dynamic covalent chemistries developed so far require either catalyst or change of environmental conditions to facilitate bond reversion and dynamic property change in bulk materials. Here we report the rational design of hindered urea bonds (urea with bulky substituent attached to its nitrogen) and the use of them to make polyureas and poly(urethane-urea)s capable of catalyst-free dynamic property change and autonomous repairing at low temperature. Given the simplicity of the hindered urea bond chemistry (reaction of a bulky amine with an isocyanate), incorporation of the catalyst-free dynamic covalent urea bonds to conventional polyurea or urea-containing polymers that typically have stable bulk properties may further broaden the scope of applications of these widely used materials.

  2. A modified manual method for the determination of urea in seawater using diacetylmonoxime reagent

    NASA Astrophysics Data System (ADS)

    Mulvenna, Pamela F.; Savidge, Graham

    1992-05-01

    A manual method for the quantitative determination of urea in seawater was developed based on the reaction of urea with diacetylmonoxime. Critical factors include the treatment of collection bottles, sample storage, pre-filtration techniques, water purification, reaction temperature and reproducible cooling of samples during analysis. The limit of detection was 0·14 ?g-at urea-N 1 -1 with Beer's Law being obeyed in the range tested of 0-15 ?g-at urea-N 1 -1. The precision (±1 SD) of replicate samples of 1,2 and 15 ?g-at urea-N 1 -1 was 0·024, 0·019 and 0·03 ?g-at urea-N 1 -1 ( n = 10) respectively.

  3. Trypsin-inspired poly(urethane-urea)s based on poly-lysine oligomer segment.

    PubMed

    Gu, Zhenqian; Wang, Fangjie; Lu, Haoxiang; Wang, Xinling; Zheng, Zhen

    2015-01-01

    A new kind of biodegradable poly(urethane-urea)s based on poly-lysine oligomer used as the soft segment was synthesized and characterized. In vitro degradation behavior of poly (urethane-urea)s was investigated, and was assessed by (1)H NMR and mass loss. The results indicated that the peptide bonds in poly(urethane-urea)s were effectively cleaved in simulated pancreatic juice containing trypsin, while those in buffer solution without trypsin remained unaffected. The degradability was obviously improved by introducing poly-lysine oligomer into the main chain of poly(urethane-urea)s. The results of cells viability test indicated that the poly (urethane-urea)s showed a good biocompatibility on endothelial cells. The thermostability and hydrophilicity of poly(urethane-urea)s increased with increase in poly-lysine oligomer content. PMID:25584962

  4. Photochemical decoration of magnetic composites with silver nanostructures for determination of creatinine in urine by surface-enhanced Raman spectroscopy.

    PubMed

    Alula, Melisew Tadele; Yang, Jyisy

    2014-12-01

    In this study, silver nanostructures decorated magnetic nanoparticles for surface-enhanced Raman scattering (SERS) measurements were prepared via photoreduction utilizing the catalytic activity of ZnO nanostructure. The ZnO/Fe3O4 composite was first prepared by dispersing pre-formed magnetic nanoparticles into alkaline zinc nitrate solutions. After annealing of the precipitates, the formed ZnO/Fe3O4 composites were successfully decorated with silver nanostructures by soaking the composites into silver nitrate/ethylene glycol solution following UV irradiations. To find the optimal condition when preparing Ag@ZnO/Fe3O4 composites for SERS measurements, factors such as the reaction conditions, photoreduction time, concentration of zinc nitrate and silver nitrate were studied. Results indicated that the photoreduction efficiency was significantly improved with the assistance of ZnO but the amount of ZnO in the composite is not critical. The concentration of silver nitrate and UV irradiation time affected the morphologies of the formed composites and optimal condition in preparation of the composites for SERS measurement was found using 20mM of silver nitrate with an irradiation time of 90 min. Under the optimized condition, the obtained SERS intensities were highly reproducible with a SERS enhancement factor in the order of 7. Quantitative analyses showed that a linear range up to 1 µM with a detection limit lower than 0.1 µM in the detection of creatinine in aqueous solution could be obtained. Successful applying of these prepared composites to determine creatinine in urine sample was obtained. PMID:25159379

  5. The Biginelli Reaction Is a Urea-Catalyzed Organocatalytic Multicomponent Reaction.

    PubMed

    Puripat, Maneeporn; Ramozzi, Romain; Hatanaka, Miho; Parasuk, Waraporn; Parasuk, Vudhichai; Morokuma, Keiji

    2015-07-17

    The recently developed artificial force induced reaction (AFIR) method was applied to search systematically all possible multicomponent pathways for the Biginelli reaction mechanism. The most favorable pathway starts with the condensation of the urea and benzaldehyde, followed by the addition of ethyl acetoacetate. Remarkably, a second urea molecule catalyzes nearly every step of the reaction. Thus, the Biginelli reaction is a urea-catalyzed multicomponent reaction. The reaction mechanism was found to be identical in both protic and aprotic solvents. PMID:26066623

  6. Influence of emulsions with and without urea on water-binding capacity of the stratum corneum

    Microsoft Academic Search

    M. GLOOR; W. GEHRING; W. WOLF

    This study was undertaken to delineate the effects of emulsions with and without urea on the water-binding behavior of the stratum corneum at different relative humidities (RH). The heels of 54 human volunteers were treated with water-in-oil (w\\/o), and oil-in-water (o\\/w) emulsions with and without urea (urea content 10%). After treatment the water content was determined by measuring the weight

  7. Causes, kinetics and clinical implications of post-hemodialysis urea rebound

    Microsoft Academic Search

    Luciano A Pedrini; Samir Zereik; Samir Rasmy

    1988-01-01

    Causes, kinetics and clinical implications of post-hemodialysis urea rebound. The rapid increase in end-dialysis urea concentration (Co) immediately after the end of dialysis (HD), which greatly exceeds that expected as an effect of urea generation and defined as “net rebound,” was assessed in 21 chronic HD patients. The curve of serial values of net rebound correlated (r = 0.70) with

  8. Molecular cloning of urea transporters from the kidneys of baleen and toothed whales

    Microsoft Academic Search

    Naoko Birukawa; Hironori Ando; Mutsuo Goto; Naohisa Kanda; Luis A. Pastene; Akihisa Urano

    2008-01-01

    Urea transport in the kidney is important for the production of concentrated urine. This process is mediated by urea transporters (UTs) encoded by two genes, UT-A (Slc14a2) and UT-B (Slc14a1). Our previous study demonstrated that cetaceans produce highly concentrated urine than terrestrial mammals, and that baleen whales showed higher concentrations of urinary urea than sperm whales. Therefore, we hypothesized that

  9. Juvenile amphibians do not avoid potentially lethal levels of urea on soil substrate.

    PubMed

    Hatch, A C; Belden, L K; Scheessele, E; Blaustein, A R

    2001-10-01

    We examined the effects of a forest fertilizer (urea) on newly metamorphosed terrestrial amphibians (Western toads, Bufo boreas; Cascades frogs, Rana cascadae; long-toed salamanders, Ambystoma macrodactylum; and roughskin newts, Taricha granulosa). We examined avoidance behavior of Western toads and Cascades frogs on both paper towel and soil substrates dosed with urea (control and 100 kg N/ha and an additional treatment of 50 kg N/ha for Western toads on soil substrate) and avoidance behavior of long-toed salamanders on soil substrate dosed with urea. We further examined the survival and feeding behavior of all four species exposed to urea on soil substrate (100 kg N/ha) for 5 d. Juvenile Western toads and Cascades frogs avoided paper towels dosed with urea but did not avoid urea-dosed soil substrate. However, Western toads and Cascades frogs both suffered significant mortality when exposed to urea on a soil substrate for 5 d. Furthermore, after adjusting for weight, we found that urea-exposed juvenile Western toads and Cascades frogs consumed significantly fewer prey items (crickets) compared with nonexposed control animals. Long-toed salamanders did not discriminate against soil substrate dosed with urea, and neither long-toed salamanders nor roughskin newts died or reduced prey consumption as a result of urea exposure. Juvenile amphibians may not be able to detect and avoid harmful levels of urea fertilizer on a natural substrate. Furthermore, anthropogenic stressors such as urea fertilizer can significantly reduce the survival and prey consumption of juvenile amphibians. These effects are important to consider in light of possible threats to the conservation status of many amphibian species. PMID:11596767

  10. Artificial Neural Network for accurate prediction of post-dialysis urea rebound

    Microsoft Academic Search

    A. T. Azar; Valentina E. Balas; Teodora Olariu

    2010-01-01

    Total dialysis dose (Kt\\/V) is considered to be a major determinant of morbidity and mortality in hemodialyzed patients. The continuous growth of the blood urea concentration over the 30- to 60-min period following dialysis, a phenomenon known as urea rebound, is a critical factor in determining the true dose of hemodialysis. The misestimation of the equilibrated (true) post-dialysis blood urea

  11. Fate of urea nitrogen applied to a banana crop in the wet tropics of Queensland

    Microsoft Academic Search

    P. Prasertsak; J. R. Freney; P. G. Saffigna; O. T. Denmead; B. G. Prove

    2001-01-01

    This paper reports a study in the wet tropics of Queensland on the fate of urea applied to a dry or wet soil surface under banana plants. The transformations of urea were followed in cylindrical microplots (10.3 cm diameter × 23 cm long), a nitrogen (N) balance was conducted in macroplots (3.85 m × 2.0 m) with 15N labelled urea,

  12. Urea cycle enzymes through the development of pacu ( Piaractus mesopotamicus ): the role of ornithine carbamoyl transferase

    Microsoft Academic Search

    Paulo Sérgio Monzani; Gilberto Moraes

    2008-01-01

    The present work reports the activities of urea cycle enzymes during the ontogenic development of the teleost pacu (Piaractus mesopotamicus). Urea cycle enzymes from the kidney and liver of adult fish were compared with those from the fish's embryonic phases. Samples\\u000a were evaluated over all phases of embryonic development, the larval period and alevin. Ammonia and urea concentrations were\\u000a determined

  13. Correlation Between C-reactive Protein and Non-enzymatic Antioxidants (Albumin, Ferritin, Uric Acid and Bilirubin) in Hemodialysis Patients

    PubMed Central

    Beciragic, Amela; Resic, Halima; Prohic, Nejra; Karamehic, Jasenko; Smajlovic, Ajdin; Masnic, Fahrudin; Ajanovic, Selma; Coric, Aida

    2015-01-01

    Introduction: Increased levels of C-Reactive Protein are found in 30-60% on hemodialysis patients and it is closely associated with the progression of atherosclerosis, cardiovascular morbidity and mortality. Non enzymatic antioxidants are antioxidants which primarily retain potentially dangerous ions of iron and copper in their inactive form and thereby prevent its participation in the production of free radicals. Aim: The aim of the study was to examine the relationship of CRP and non enzymatic antioxidants (albumin, ferritin, uric acid and bilirubin) i.e. examine the importance of CRP as a serum biomarker in assessing the condition of inflammation and its relationship to antioxidant protection in patients on hemodialysis. Methods: The study was cross-sectional, clinical, comparative and descriptive. The study involved 100 patients (non diabetic) on chronic hemodialysis. The control group consisted of 50 subjects without subjective and objective indicators of chronic renal disease. In all patients, the concentration of CRP as well as concentrations of non enzymatic antioxidants were determined. Results: In the group of hemodialysis patients 60% were men and 40% women. The average age of hemodialysis patients was 54.13 ± 11.8 years and the average age of the control group 41.72 ± 9.8 years. The average duration of hemodialysis treatment was 91.42 ± 76.2 months. In the group of hemodialysis patients statistically significant, negative linear correlation was determined between the concentration of CRP in and albumin concentration (rho = -0.251, p = 0.012) as well as negative, statistics insignificant, linear correlation between serum CRP and the concentration of uric acid (r = -0.077, p = 0.448). Furthermore, the positive, linear correlation was determined between serum CRP and ferritin (r = 0.159, p = 0.114) and positive linear correlation between CRP and total serum bilirubin (r = 0.121, p = 0.230). In the control group was determined a statistically significant, positive, linear correlation between serum CRP and uric acid concentration (rho = 0.438, p = 0.001) and statistically significant, positive, linear correlation between serum CRP and total serum bilirubin (rho = 0.510, p = 0.0001) A statistically significant, negative linear correlation was determined between CRP and albumin concentration (rho= -0.393, p = 0.005) as well as statistically significant, negative linear correlation between serum CRP and ferritin control group (rho = -0.391, p = 0.005). Conclusion: Elevated CRP level is a strong and independent predictor of low levels of serum albumin, which indicates that the hypoalbuminemia in hemodialysis patients could be more due to inflammation than malnutrition. There was no statistically significant correlation between CRP and other non enzymatic antioxidants (uric acid, ferritin, bilirubin), which shows that indicators of antioxidant defense in hemodialysis patients must be individually measured to determine their actual stocks and activity. PMID:26005382

  14. Substrate Orientation and Catalytic Specificity in the Action of Xanthine Oxidase: The Sequential Hydroxylation of Hypoxanthine to Uric Acid

    SciTech Connect

    Cao, Hongnan; Pauff, James M.; Hille, Russ (UCR)

    2010-11-29

    Xanthine oxidase is a molybdenum-containing enzyme catalyzing the hydroxylation of a sp{sup 2}-hybridized carbon in a broad range of aromatic heterocycles and aldehydes. Crystal structures of the bovine enzyme in complex with the physiological substrate hypoxanthine at 1.8 {angstrom} resolution and the chemotherapeutic agent 6-mercaptopurine at 2.6 {angstrom} resolution have been determined, showing in each case two alternate orientations of substrate in the two active sites of the crystallographic asymmetric unit. One orientation is such that it is expected to yield hydroxylation at C-2 of substrate, yielding xanthine. The other suggests hydroxylation at C-8 to give 6,8-dihydroxypurine, a putative product not previously thought to be generated by the enzyme. Kinetic experiments demonstrate that >98% of hypoxanthine is hydroxylated at C-2 rather than C-8, indicating that the second crystallographically observed orientation is significantly less catalytically effective than the former. Theoretical calculations suggest that enzyme selectivity for the C-2 over C-8 of hypoxanthine is largely due to differences in the intrinsic reactivity of the two sites. For the orientation of hypoxanthine with C-2 proximal to the molybdenum center, the disposition of substrate in the active site is such that Arg880 and Glu802, previous shown to be catalytically important for the conversion of xanthine to uric acid, play similar roles in hydroxylation at C-2 as at C-8. Contrary to the literature, we find that 6,8-dihydroxypurine is effectively converted to uric acid by xanthine oxidase.

  15. Effect of Oral Vitamin C Supplementation on Serum Uric Acid: A Meta-analysis of Randomized Controlled Trials

    PubMed Central

    Juraschek, Stephen P.; Miller, Edgar R.; Gelber, Allan C.

    2011-01-01

    Objective To assess the effect of vitamin C supplementation on serum uric acid (SUA) by pooling the findings from published randomized, controlled trials (RCTs). Methods A total of 2,082 publications identified through systematic search were subjected to the following inclusion criteria: (1) RCTs conducted on human subjects; (2) reported end-trial SUA means and variance; (3) study design with oral vitamin C supplementation and concurrent control groups; and (4) trial duration of at least one week. Trials that enrolled children or patients on dialysis were excluded. Two investigators independently abstracted trial and participant characteristics. SUA effects were pooled by random-effects models and weighted by inverse variance. Results Thirteen RCTs were identified in MEDLINE, EMBASE, and CENTRAL databases. The total number of participants was 556, median dose of vitamin C was 500 mg/d, trial size ranged from 8 to 184 participants, and median study duration was 30 days. Pretreatment SUA values ranged from 2.9 to 7.0 mg/dL (SI: 172.5 – 416.4 ?mol/L). The combined effect of these trials was a significant reduction in SUA of -0.35 mg/dL (95% CI: -0.66, -0.03; P = 0.032; SI: -20.8 ?mol/L). Trial heterogeneity was significant (I2 = 77%; P < 0.01). Subgroup analyses based on trial characteristics indicated larger reductions in uric acid in trials that were placebo-controlled. Conclusions In aggregate, vitamin C supplementation significantly lowered SUA. Future trials are needed to determine whether vitamin C supplementation can reduce hyperuricemia or prevent incident and recurrent gout. PMID:21671418

  16. Poly(Urethane–Urea) Varnishes Containing Tributyltin Groups

    Microsoft Academic Search

    Constantin Gaina; Viorica Gaina; Mariana Cristea

    2009-01-01

    New poly(urethane–urea) varnishes containing tributyltin groups were prepared by the reaction of dibenzyldiisocyanate in excess\\u000a with a macrodiol (PEGA-2000), trimethylolpropane, diethylene glycol and a bisalcohol maleimide monomer containing tributyltin\\u000a carboxylate group. Tributyltin maleimide monomers were obtained from 4-{3,4-bis[(2-hydroxyethyl)sulfanyl]-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl}benzoic acid and bis(tributyltin) oxide. Structure of monomers and polymers was confirmed by the IR, NMR spectroscopy\\u000a and elemental analysis. The polymer films

  17. Significantly enhanced dehydrogenation properties of calcium borohydride combined with urea.

    PubMed

    Chu, Hailiang; Qiu, Shujun; Liu, Lin; Zou, Yongjin; Xiang, Cuili; Zhang, Huanzhi; Xu, Fen; Sun, Lixian; Zhou, Huaiying; Wu, Guotao

    2014-11-01

    The interaction of [BH(x)]- and [NH(x)]-containing species gives rise to molecular hydrogen and the establishment of the B-N bond. Up to now, metal amides and ammonia are the commonly used [NH(x)] sources. Herein, urea, an organic carbonyl diamide, was used to react with Ca(BH4)2. A new type of complex hydride Ca(BH4)2·4CO(NH2)2 was synthesized with release of ca. 5.2 wt% hydrogen below 250 °C. PMID:25186984

  18. [Source analysis of urea-N in Lake Taihu during summer].

    PubMed

    Han, Xiao-Xi; Zhu, Guang-Wei; Xu, Hai; Wilhelm, Steven W; Qin, Bo-Qiang; Li, Zhao-Fu

    2014-07-01

    To study the effect of urea nitrogen on the ecosystem of Lake Taihu, we conducted urea and various nitrogen analysis for the water samples collected from the lake and surrounding rivers during summer. The ecological index analysis of 82 sites in rivers and lake yielded the following results: (1) The urea nitrogen contents in Taihu ranged from 0.011 to 0.161 mg x L(-1), which was high in the northwest and low in the southeast, related to the main pollution sources distribution of its drainage basin. (2) The dissolved nitrogen was dominated by inorganic nitrogen and the ratio between ammonia nitrogen and nitrate nitrogen was 5: 1. The average percentage of urea nitrogen in total nitrogen, dissolved nitrogen, dissolved organic nitrogen and bioavailable nitrogen was respectively 2.28%, 5.91%, 15.86%, and 6.22%, which showed a significant ecological function in Taihu. (3) Urea nitrogen concentration in river was more than twice that in lake, and the lake river concentration was slightly higher than the river into the lake. (3) In Taihu, there was a transformation relationship between urea nitrogen and the nitrogen in other forms. It showed that urea nitrogen had a significant positive correlation with permanganate index and the other forms of nitrogen, and a significant negative correlation with dissolved oxygen. In addition, urea nitrogen was weakly and positively correlated with chlorophyll a, while closely related to the spatial distribution of benthos and zooplankton species. All the results above showed that urea nitrogen was the bridge of organic and inorganic nitrogen transformation, and was the sign of nitrogen cycle of Lake Taihu, which was controlled by the circulating rate. High nitrogen content (especially the organic nitrogen) and low dissolved oxygen content were the key contributors to the increased urea nitrogen content. In Taihu, the urea nitrogen content was affected by both exogenous input and endogenous release. PMID:25244836

  19. Banding of urea increased ammonia volatilization in a dry acidic soil.

    PubMed

    Rochette, Philippe; Macdonald, J Douglas; Angers, Denis A; Chantigny, Martin H; Gasser, Marc-Olivier; Bertrand, Normand

    2009-01-01

    Volatilization of ammonia following application of urea contributes to smog formation and degradation of natural ecosystems. The objective of this study was to evaluate the impact of (i) incorporation and banding of urea and (ii) surface broadcast of slow-release urea types on NH(3) volatilization in a dry acidic soil. Volatilization was measured using wind tunnels for 25 d after standard urea (140 kg N ha(-1)) was broadcast, broadcast and incorporated (0-5 cm), or incorporated in shallow bands (3-5 cm) to a conventionally tilled silty loam soil. Urea supplemented with a urease inhibitor or coated with a polymer was also broadcast at the soil surface. Little N diffused out of the polymer-coated granules and ammonia losses were low (4% of applied N). Use of a urease inhibitor also resulted in a low NH(3) loss (5% of applied N) while maintaining soil mineral N at levels similar to plots where untreated urea was broadcast. The rate of hydrolysis of urea broadcast at the soil surface was slowed by the lack of moisture and NH(3) loss (9% applied N) was the lowest of all treatments with standard urea. Incorporation of broadcast urea increased emissions (16% applied N) by increasing urea hydrolysis relative to surface application. Furthermore, incorporation in band also increased emissions (27% applied N) due to a localized increase in soil pH from 6.0 to 8.7. We conclude that incorporating urea in bands in a dry acidic soil can increase NH(3) volatilization compared to broadcast application followed by incorporation. PMID:19465713

  20. Examining urea flux across the intestine of the spiny dogfish, Squalus acanthias.

    PubMed

    Gary Anderson, W; McCabe, Chris; Brandt, Catherine; Wood, Chris M

    2015-03-01

    Recent examination of urea flux in the intestine of the spiny dogfish shark, Squalus acanthias, has shown that feeding significantly enhances urea uptake across the intestine, and this was significantly inhibited following mucosal addition of phloretin. The present study examined potential mechanisms of urea uptake across the dogfish intestine in starved and fed dogfish. Unidirectional flux chambers were used to examine the kinetics of urea uptake, and to determine the influence of sodium, ouabain, competitive urea analogues, and phloretin on urea uptake across the gut of fed dogfish. Intestinal epithelial preparations from starved and fed dogfish were mounted in Ussing chambers to examine the effect of phloretin on bidirectional solute transport across the intestine. In the unidirectional studies, the maximum uptake rate of urea was found to be 35.3±6.9 ?mol.cm(-2).h(-1) and Km was found to be 291.8±9.6 mM in fed fish, and there was a mild inhibition of urea uptake following mucosal addition of competitive agonists. Addition of phloretin, Na-free Ringers and ouabain to the mucosal side of intestinal epithelia also led to a significant reduction in urea uptake in fed fish. In the Ussing chamber studies there was a net influx of urea in fed fish and a small insignificant efflux in starved fish. Addition of phloretin blocked urea uptake in fed fish when added to the mucosal side. Furthermore, phloretin had no effect on ion transport across the intestinal epithelia with the exception of the divalent cations, magnesium and calcium. PMID:25479361

  1. On the urea induced hydrophobic collapse of a water soluble polymer.

    PubMed

    Rodríguez-Ropero, Francisco; van der Vegt, Nico F A

    2015-04-01

    Stabilization of macromolecular folded states in solution by protective osmolytes has been traditionally explained on the basis of preferential osmolyte depletion from the macromolecule's first solvation shell. However recent theoretical and experimental studies suggest that protective osmolytes may directly interact with the macromolecule. An example is the stabilization of the collapsed globular state of poly(N-isopropylacrylamide) (PNiPAM) by urea in aqueous solution. Based on Molecular Dynamics simulations we have characterized the mechanism through which urea stabilizes the collapsed state of PNiPAM in water. Analysis and comparison of the different components of the excess chemical potentials of folded and unfolded PNiPAM chains in aqueous urea solutions indicates that enthalpic interactions play no role in stabilizing the collapsed state. We instead find that with increasing urea, solvation of the unfolded state is entropically penalized over solvation of the folded state, thereby shifting the folding equilibrium in favour of the folded state. The unfavourable entropy contribution to the excess chemical potential of unfolded PNiPAM chains results from two urea effects: (1) an increasing cost of cavity formation with increasing urea, (2) larger fluctuations in the energy component corresponding to PNiPAM-(co)solvent attractive interactions. These energy fluctuations are particularly relevant at low urea concentrations (<3 M) and result from attractive polymer-urea van der Waals interactions that drive the formation of "urea clouds" but bias the spatial distribution of urea and water molecules with a corresponding reduction of the entropy. We further find indications that urea increases the entropy of the globular state. PMID:25684267

  2. Binding of carboxylic acids by fluorescent pyridyl ureas.

    PubMed

    Jordan, Lisa M; Boyle, Paul D; Sargent, Andrew L; Allen, William E

    2010-12-17

    Fluorescent pyrid-2-yl ureas were prepared by treating halogenated 2-aminopyridines with hexyl isocyanate, followed by Sonogashira coupling with arylacetylenes. The sensors emit light of ?360 nm with quantum yields of 0.05-0.1 in acetonitrile solution. Addition of strong organic acids (pK(a) < 13 in CH(3)CN) shifts the fluorescence band to lower energy, and clean isoemissive behavior is observed. Fluorescence response curves (i.e., F/F(0) vs [acid](total)) are hyperbolic in shape for CCl(3)COOH and CF(3)COOH, with association constants on the order of 10(3) M(-1) for both acids. (1)H NMR titrations and DFT analyses indicate that trihaloacetic acids bind in ionized form to the receptors. Pyridine protonation disrupts an intramolecular H-bond, thereby unfolding an array of ureido NH donors for recognition of the corresponding carboxylates. Methanesulfonic acid protonates the sensors, but no evidence for conjugate base binding at the urea moiety is found by NMR. An isosteric control compound that lacks an integrated pyridine does not undergo significant fluorescence changes upon acidification. PMID:21080667

  3. Uric Acid Level Has a U-Shaped Association with Loss of Kidney Function in Healthy People: A Prospective Cohort Study

    PubMed Central

    Kanda, Eiichiro; Muneyuki, Toshitaka; Kanno, Yoshihiko; Suwa, Kaname; Nakajima, Kei

    2015-01-01

    Background The relationship between hyperuricemia and chronic kidney disease (CKD) has been found in various observational studies. Although hypouricemia is associated with cardiovascular events, it has not been established as a risk factor for CKD. We investigated the relationship between serum uric acid level and the loss of kidney function and incident CKD in healthy people. Materials and Methods Healthy people were enrolled in this community-based prospective cohort study, the Saitama Cardiometabolic Disease and Organ Impairment Study, Japan. The analysis was conducted on 4188 subjects followed up for at least 3 years, 3102 for 6 years and 1052 for 9 years. Their data including glomerular filtration rate (eGFR) decline were examined every three years. The outcome event was incident CKD or the decrease in eGFR by more than 25% in three years. Multivariate statistical models were adjusted for the baseline characteristics. Results The following data was obtained: mean±SD age, male, 39.6±10.4 years, female 38.4±10.8 years; eGFR, male, 81.9±16.4 ml/min/1.73m2, female, 82.1±17.5 ml/min/1.73m2; serum uric acid level, male, 5.8±1.2 mg/dl, female, 4.1±0.9 mg/dl. Both low and high serum uric acid levels were associated with the outcome and eGFR decline in males (multivariate logistic additional additive models, linear p = 0.0001, spline p = 0.043; generalized additive models, linear p = 0.0001, spline p = 0.012). In subjects with low serum uric acid levels (male, <5 mg/dl; female, <3.6 mg/dl), multivariate linear mixed models showed that low serum uric acid levels were associated with eGFR decline in a time-dependent manner (male, p = 0.0001; female, p = 0.045). Conclusion This study showed that low as well as high levels of uric acid are associated with the loss of kidney function. Hypouricemia is a candidate predictor of kidney function decline in healthy people. PMID:25658588

  4. Serum Uric Acid Is Associated with Incident Chronic Kidney Disease in Middle-Aged Populations: A Meta-Analysis of 15 Cohort Studies

    PubMed Central

    Zhu, Ping; Liu, Yan; Han, Lu; Xu, Gang; Ran, Jian-min

    2014-01-01

    Background Mounting evidence indicates that elevated serum uric acid may increase the incidence of chronic kidney disease (CKD). Our goal was to systematically evaluate longitudinal cohort studies for the association of serum uric acid levels and incident CKD. Methods We searched electronic databases and the reference lists of relevant articles. The primary outcome was incident CKD, which was defined as an eGFR less than 60 mL/min/1.73 m2 at the follow-up examination. Study-specific risk estimates were combined using random-effects models. The included studies were stratified into subgroups, and meta-regression analyses were performed. Results Fifteen unique cohorts with a total of 99,205 individuals and 3,492 incident CKD cases were included. The relative risk of CKD was 1.22 (95% CI 1.16–1.28, I2?=?65.9%) per 1 mg/dL serum uric level increment. This positive association was consistently observed in subgroups stratified according to most of the study-level characteristics. The observed positive association was more pronounced among group with a mean age <60 years (RR 1.26, 95% CI 1.21–1.31), and low-level heterogeneity was observed in the findings for this age group (I2?=?46.4%, P?=?0.022). However, no association was observed among studies with a mean age?60 years (RR 1.04, 95% CI 0.96–1.13), and no evidence of heterogeneity was evident among the studies (I2?=?0%, P?=?0.409). This mean age-related difference in the association between serum uric acid levels and CKD was significant (P?=?0.004). The sensitivity analysis results were consistent when the analyses were restricted to studies that controlled for proteinuria and metabolic syndrome. Conclusions Our meta-analysis demonstrated a positive association between serum uric acid levels and risk of CKD in middle-aged patients independent of established metabolic risk factors. Future randomized, high-quality clinical trials are warranted to determine whether lowering uric acid levels is beneficial in CKD. PMID:24959886

  5. Urinary amylase / urinary creatinine ratio (uAm/uCr) - a less-invasive parameter for management of hyperamylasemia

    PubMed Central

    2013-01-01

    Background The serum level of amylase (sAm) is commonly used as a biochemical marker for diagnosis and management of pancreatic disorders. However, the use of the urine level of amylase (uAm) is limited in practice, because the diagnostic ability of uAm is inferior to that of sAm. In the present study, the possible concordance of uAm-rerated parameters with sAm was investigated, and evaluate the usefulness of uAm for management of hyperamylasemia. Methods From June 1995 to October 2009, 804 samples of both urine and blood were collected from 128 patients in order to measure the serum level of amylase (sAm) and the urine level of amylase (uAm) and creatinine (uCr). Concordance of parameters using uAm compared to sAm was assessed. Parameters used were uAm, amylase creatinine clearance ratio (ACCR), and the ratio of uAm to uCr (uAm/uCr). Results uAm/uCr had the best correlation with sAm (r =?0.779, p

  6. Simultaneous determination of creatinine and creatine in human serum by double-spike isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS).

    PubMed

    Fernández-Fernández, Mario; Rodríguez-González, Pablo; Ańón Álvarez, M Elena; Rodríguez, Felix; Menéndez, Francisco V Álvarez; García Alonso, J Ignacio

    2015-04-01

    This work describes the first multiple spiking isotope dilution procedure for organic compounds using (13)C labeling. A double-spiking isotope dilution method capable of correcting and quantifying the creatine-creatinine interconversion occurring during the analytical determination of both compounds in human serum is presented. The determination of serum creatinine may be affected by the interconversion between creatine and creatinine during sample preparation or by inefficient chemical separation of those compounds by solid phase extraction (SPE). The methodology is based on the use differently labeled (13)C analogues ((13)C1-creatinine and (13)C2-creatine), the measurement of the isotopic distribution of creatine and creatinine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the application of multiple linear regression. Five different lyophilized serum-based controls and two certified human serum reference materials (ERM-DA252a and ERM-DA253a) were analyzed to evaluate the accuracy and precision of the proposed double-spike LC-MS/MS method. The methodology was applied to study the creatine-creatinine interconversion during LC-MS/MS and gas chromatography-mass spectrometry (GC-MS) analyses and the separation efficiency of the SPE step required in the traditional gas chromatography-isotope dilution mass spectrometry (GC-IDMS) reference methods employed for the determination of serum creatinine. The analysis of real serum samples by GC-MS showed that creatine-creatinine separation by SPE can be a nonquantitative step that may induce creatinine overestimations up to 28% in samples containing high amounts of creatine. Also, a detectable conversion of creatine into creatinine was observed during sample preparation for LC-MS/MS. The developed double-spike LC-MS/MS improves the current state of the art for the determination of creatinine in human serum by isotope dilution mass spectrometry (IDMS), because corrections are made for all the possible errors derived from the sample preparation step. PMID:25751287

  7. Biomechanical studies on aliphatic physically crosslinked poly(urethane urea) for blood contact applications.

    PubMed

    Thomas, Vinoy; Muthu, Jayabalan

    2008-07-01

    Hydrophobic and physically crosslinked (virtually crosslinked through hydrogen bonding) aliphatic poly(urethane urea)s were developed and characterized for its biomechanical properties. The aging under induced-stress (bend samples) condition reveals resistance of poly(urethane urea) to environmental stress corrosion cracking (ESC) in hydrolytic media, Ringer's solution and phosphate buffered saline at 50 degrees C. The strain-induced (20% tensile strain) and aged polymer in hydrolytic enzyme medium, papain and in buffer reveals increase of elastic modulus in papain enzyme and papain buffer. The increase of elastic modulus is attributed to unidirectional reorganisation of chains under continually strained conditions. The polymer exposed in boiling alcoholic potassium hydroxide solution (accelerated hydrolytic chemical degradation) reveals no degradation. A comparative evaluation of poly(ether urethane urea)s reveals inferior properties. Poly(ether urethane urea)s polymer undergo hydrolytic degradation in boiling alcoholic potassium hydroxide solution. The candidate poly(urethane urea) HFL 18-PUU is more promising elastomer for long-term biomechanically sensitive blood contact applications such as heart valve and blood pump diaphragm of left ventricular assist device. PMID:18305906

  8. Coating of Prilled Urea with Neem (Azadirachta Indica Juss) Oil for Efficient Nitrogen Use in Rice

    Microsoft Academic Search

    R. Prasad; S. Singh; V. S. Saxena; C. Devkumar

    1999-01-01

    A field study made with rice at the Indian Agricultural Research Institute, New Delhi, showed that coating urea with neem\\u000a oil, neem cake or neem oil microemulsion improved rice growth and resulted in more grain and straw than did commercial prilled\\u000a urea.

  9. Coating of prilled urea with neem (Azadirachta indica juss) oil for efficient nitrogen use in rice

    PubMed

    Prasad; Singh; Saxena; Devkumar

    1999-11-01

    A field study made with rice at the Indian Agricultural Research Institute, New Delhi, showed that coating urea with neem oil, neem cake or neem oil microemulsion improved rice growth and resulted in more grain and straw than did commercial prilled urea. PMID:10551949

  10. Coating of Prilled Urea with Neem (Azadirachta Indica Juss) Oil for Efficient Nitrogen Use in Rice

    NASA Astrophysics Data System (ADS)

    Prasad, R.; Singh, S.; Saxena, V. S.; Devkumar, C.

    A field study made with rice at the Indian Agricultural Research Institute, New Delhi, showed that coating urea with neem oil, neem cake or neem oil microemulsion improved rice growth and resulted in more grain and straw than did commercial prilled urea.

  11. Salt-stabilized globular protein structure in 7 M aqueous urea solution

    E-print Network

    Wider, Gerhard

    1 Salt-stabilized globular protein structure in 7 M aqueous urea solution V. Dötsch,1 G. Wider, G Hochschule- Hönggerberg, CH-8093 Zürich, Switzerland Keywords Protein folding; Urea denaturation; Salt changing the solution conditions. In this paper we describe the influence of various salts or non

  12. Soy flour adhesive modified with urea, citric acid and boric acid

    Microsoft Academic Search

    F. Li; X. P. Li; W. H. Wang

    2010-01-01

    Purpose – The purpose of this paper is to investigate an adhesive prepared from soy flour (SF) modified with urea, citric acid and boric acid as an environmentally friendly product for the wood industry. Design\\/methodology\\/approach – Urea solution was prepared at 30°C and then SF was added and stirred at 30°C for 2 hours. Citric acid solution was added and

  13. COMPARISON OF THREE ANALYTICAL METHODS TO ASSESS UREA NITROGEN IN COLOSTRUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Milk urea nitrogen (MUN) obtained from cows fed mid to late lactation diets has been used as an indicator of diet composition adequacy and can be used to predict urine urea nitrogen. However, recent research has suggested that in early lactation, MUN was positively correlated with feed efficiency (...

  14. Evaluation of milk urea nitrogen as a management tool to reduce ammonia emissions from dairy farms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to compile and evaluate relationships between feed nitrogen (N) intake, milk urea N (MUN), urinary urea N (UUN) and ammonia (NH3) emissions from dairy farms to aid policy development. Regression relationships between MUN (within the range of 10 to 25 mg/dL), UUN, and re...

  15. Concentration of ?-Linoleic Acid of Perilla Oil by Gradient Cooling Urea Inclusion

    Microsoft Academic Search

    Hai-bo GU; Xue-yi MA; Jing-bo WU; Qi ZHANG; Wen-bing YUAN; Yi-ping CHEN

    2009-01-01

    In this study, production of ?-linoleic acid concentrated from crude perilla oil by gradient cooling urea inclusion was optimized. The fatty acid composition was determined after ethyl esterification by gas chromatography (GC). In this process, orthogonal experiment was carried out. Under optimum conditions, the maximum amount of ?-linoleic acid (91.5%) was obtained at a urea to fatty acid ratio of

  16. Effect of Granular Urea Placement on Nitrous Oxide Production from a Silt Loam Soil

    E-print Network

    Lawrence, Rick L.

    Effect of Granular Urea Placement on Nitrous Oxide Production from a Silt Loam Soil Richard Engel1 emission patterns and losses from urea prills applied to a silt loam soil using band, nest, and broadcast, and the soil is classified as an Amsterdam silt loam (fine-silty, mixed, superactive, frigid Typic Haplustolls

  17. Effect of urea on sodium bis(2-ethylhexyl) sulfosuccinate thin films on solid substrates

    Microsoft Academic Search

    Carmen Lúcia Costa Amaral; Mário José Politi

    2004-01-01

    The effect of urea on sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reversed micelles films deposited on hydrophobic and hydrophilic glass substrates was studied by optical and electron microscopy. Films growth in the absence of urea presented a droplet aspect, whereas in its presence, the films had a more tubular structure and seemed to merge one into the other suggesting a less rigid

  18. MICROWAVE ASSISTED PREPARATION OF CYCLIC UREAS FROM DIAMINES IN THE PRESENCE OF ZNO

    EPA Science Inventory

    A microwave-assisted facile method for the preparation of various ureas, cyclic ureas, and urethanes has been developed that affords nearly quantitative yield of products at 120 degrees C (150 W), 71 kPa within 10 min using ZnO as a catalyst. The enhanced selectivity in this rea...

  19. Factors Influencing Intake of High Urea-Containing Rations by Lactating Dairy Cows

    Microsoft Academic Search

    A. F. Kertz; M. K. Koepke; L. E. Davidson; N. L. Betz; J. R. Norris; L. V. Skoch; B. R. Cords; D. T. Hopkins

    1982-01-01

    In a series of experiments we inves- tigated effects of several factors on intake of urea by lactating dairy cows. Cows given an unfamiliar ingredient or altered moisture in the ration reduced their in- take, and this effect was attributed to a newness factor. Addition of urea to a ration may have a similar effect. An experimental design providing both

  20. Morphological and functional characteristics of the kidney of cartilaginous fishes: with special reference to urea reabsorption.

    PubMed

    Hyodo, Susumu; Kakumura, Keigo; Takagi, Wataru; Hasegawa, Kumi; Yamaguchi, Yoko

    2014-12-15

    For adaptation to high-salinity marine environments, cartilaginous fishes (sharks, skates, rays, and chimaeras) adopt a unique urea-based osmoregulation strategy. Their kidneys reabsorb nearly all filtered urea from the primary urine, and this is an essential component of urea retention in their body fluid. Anatomical investigations have revealed the extraordinarily elaborate nephron system in the kidney of cartilaginous fishes, e.g., the four-loop configuration of each nephron, the occurrence of distinct sinus and bundle zones, and the sac-like peritubular sheath in the bundle zone, in which the nephron segments are arranged in a countercurrent fashion. These anatomical and morphological characteristics have been considered to be important for urea reabsorption; however, a mechanism for urea reabsorption is still largely unknown. This review focuses on recent progress in the identification and mapping of various pumps, channels, and transporters on the nephron segments in the kidney of cartilaginous fishes. The molecules include urea transporters, Na(+)/K(+)-ATPase, Na(+)-K(+)-Cl(-) cotransporters, and aquaporins, which most probably all contribute to the urea reabsorption process. Although research is still in progress, a possible model for urea reabsorption in the kidney of cartilaginous fishes is discussed based on the anatomical features of nephron segments and vascular systems and on the results of molecular mapping. The molecular anatomical approach thus provides a powerful tool for understanding the physiological processes that take place in the highly elaborate kidney of cartilaginous fishes. PMID:25339681

  1. Crystalline Bis-urea Nanochannel Architectures Tailored for Single-File Diffusion Studies.

    PubMed

    Bowers, Clifford R; Dvoyashkin, Muslim; Salpage, Sahan R; Akel, Christopher; Bhase, Hrishi; Geer, Michael F; Shimizu, Linda S

    2015-06-23

    Urea is a versatile building block that can be modified to self-assemble into a multitude of structures. One-dimensional nanochannels with zigzag architecture and cross-sectional dimensions of only ?3.7 Ĺ × 4.8 Ĺ are formed by the columnar assembly of phenyl ether bis-urea macrocycles. Nanochannels formed by phenylethynylene bis-urea macrocycles have a round cross-section with a diameter of ?9.0 Ĺ. This work compares the Xe atom packing and diffusion inside the crystalline channels of these two bis-ureas using hyperpolarized Xe-129 NMR. The elliptical channel structure of the phenyl ether bis-urea macrocycle produces a Xe-129 powder pattern line shape characteristic of an asymmetric chemical shift tensor with shifts extending to well over 300 ppm with respect to the bulk gas, reflecting extreme confinement of the Xe atom. The wider channels formed by phenylethynylene bis-urea, in contrast, present an isotropic dynamically average electronic environment. Completely different diffusion dynamics are revealed in the two bis-ureas using hyperpolarized spin-tracer exchange NMR. Thus, a simple replacement of phenyl ether with phenylethynylene as the rigid linker unit results in a transition from single-file to Fickian diffusion dynamics. Self-assembled bis-urea macrocycles are found to be highly suitable materials for fundamental molecular transport studies on micrometer length scales. PMID:26035000

  2. Dialysis system. [using ion exchange resin membranes permeable to urea molecules

    NASA Technical Reports Server (NTRS)

    Mueller, W. A. (inventor)

    1978-01-01

    The improved hemodialysis system utilizes a second polymeric membrane having dialyzate in contact with one surface and a urea decomposition solution in contact with the other surface. The membrane selectively passes urea from the dialyzate into the decomposition solution, while preventing passage of positively charged metal ions from the dialyzate into the solution and ammonium ions from the solution into the dialyzate.

  3. Microbial protein production determined by urinary allantoin and renal urea sparing in normal

    E-print Network

    Paris-Sud XI, Université de

    Short note Microbial protein production determined by urinary allantoin and renal urea sparing. Renal functional tests for urea handling studies, and determination of urinary allantoin as an indirect of allantoin, thereby leading to an underestimation of the amount of microbial protein entering in the duodenum

  4. Determination of urea and its thermal decomposition products by high-performance liquid chromatography

    Microsoft Academic Search

    Manfred Koebel; Martin Elsener

    1995-01-01

    The thermal decomposition of urea can yield a wide variety of products; apart from ammonia and isocyanic acid, addition compounds of higher molecular mass may appear. In order to detect their presence in exhaust gases from a selective catalytic reduction (SCR) process using urea as a reducing agent, a chromatographic method was developed. The chromatographic separation is performed on an

  5. 75 FR 51055 - Propionic Acid and Salts, and Urea Sulfate; Registration Review Proposed Decisions; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ...EPA-HQ-OPP-2010-0650; FRL-8840-5] Propionic Acid and Salts, and Urea Sulfate; Registration...decisions for the pesticides propionic acid and salts, and urea sulfate and opens...decisions. The active ingredient propionic acid is a fungicide and bactericide that...

  6. Comparison of hydrogen bonding in polydimethylsiloxane and polyether based urethane and urea copolymers

    Microsoft Academic Search

    E. Yilgör; E. Burgaz; E. Yurtsever

    2000-01-01

    Hydrogen bonding in polydimethylsiloxane and polyether based urethane and urea type segmented copolymers was investigated by infrared spectroscopy, differential scanning calorimetry and quantum mechanical calculations. Hydrogen bonding in model urethane and urea compounds was compared with those of the copolymers, in order to determine the extent of interaction and resulting phase mixing between hard and soft segments in these copolymers.

  7. Peptidyl-urea based inhibitors of soluble epoxide hydrolases Christophe Morisseau,a

    E-print Network

    Hammock, Bruce D.

    Peptidyl-urea based inhibitors of soluble epoxide hydrolases Christophe Morisseau,a John W. Newman a series of amino acid derived cyclohexyl and adamantyl ureas and tested them as inhibitors of the human than previously described sEH inhibitors. While our lead compound 2 showed low apparent bioavailability

  8. Milk Urea Testing as a Tool to Monitor Reproductive Performance in Ontario Dairy Herds

    Microsoft Academic Search

    S. M. Godden; D. F. Kelton; K. D. Lissemore; J. S. Walton; K. E. Leslie; J. H. Lumsden

    2001-01-01

    Dairy herd improvement test-day data, including milk urea concentrations measured using infrared test method, were collected from 60 commercial Ontario Holstein dairy herds for a 13-mo period between Decem- ber 1, 1995, and December 31, 1996. The objective of the study was to describe, at the cow and the group level, the relationship between DHI milk urea concen- trations and

  9. EFFECTS OF DIETARY CRUDE PROTEIN ON SERUM AND URINE UREA NITROGEN IN FEEDLOT STEERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the effects of dietary CP concentration and source on serum urea N (SUN) and urine urea N (UUN). A metabolism trial with three collection periods (approximately d 35, 95, and 155 on feed) was conducted using twenty seven crossbred steers (average BW = 353.2 ± 8.4 kg). Treatments were ...

  10. 77 FR 64464 - Solid Urea From the Russian Federation: Antidumping Duty Administrative Review; 2010-2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-22

    ...order on solid urea from the Russian Federation (Russia). The...Department of Commerce, 14th Street and Constitution Avenue NW., Washington...Russia. See Solid Urea From the Russian Federation: Preliminary Results...is provided for convenience and customs purposes, the...

  11. 76 FR 66690 - Solid Urea From the Russian Federation: Final Results of Antidumping Duty Administrative Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ...on solid urea from the Russian Federation. The solid...this review was produced and exported by MCC EuroChem...versions of the Issues and Decision Memorandum are...on solid urea from the Russian Federation produced and exported by EuroChem...

  12. 78 FR 67335 - Solid Urea From the Russian Federation: Final Results of Antidumping Duty Administrative Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-12

    ...A-821-801] Solid Urea From the Russian Federation: Final Results of...2011-2012 AGENCY: Enforcement and Compliance (formerly Import...order on solid urea from the Russian Federation (Russia). For...Operations, Office I, Enforcement and Compliance (E&C),...

  13. 13C-urea breath test in the management of Helicobacter pylori infection

    Microsoft Academic Search

    J. P. Gisbert; J. M. Pajares

    2005-01-01

    The urea breath test is a noninvasive and very accurate test for the diagnosis of Helicobacter pylori infection. However, false negative urea breath test results have been reported to occur in a considerable percentage of the individuals taking proton pump inhibitors; the interval needed to be completely confident that false negative tests had been excluded has varied among the different

  14. Effect of urea on growth and microcystins production of Microcystis aeruginosa.

    PubMed

    Wu, Xuanhao; Yan, Yangwei; Wang, Pinfei; Ni, Lanqi; Gao, Jiayi; Dai, Ruihua

    2015-04-01

    The effects of urea on the growth and toxin content of Microcystis aeruginosa isolated from Dianchi Lake in China were investigated. Experiments were carried out in lab using (15)N isotopic technique to characterize urea-N biosynthesis to microcystins. High urea concentration (3.6 mmol-N L(-1)) would restrict the growth of M.aeruginosa and the production of microcystin-LR, while low urea concentration (0.4-1.4 mmol-N L(-1)) would promote the growth of M.aeruginosa and the production of microcystin-LR. The (15)N labeling experiment further demonstrated that there existed selectivity when M.aeruginosa assimilated urea to form its structure. The majority of M.aeruginosa assimilated 1 urea molecule at first which was biosynthesized into the Ala or Leu residue. On day 18, The m/z=1004 parent ion assimilated 9 (15)N except that the Mdha residue did not assimilate any urea-(15)N. The results give deeper insight to the biosynthesis of urea into microcystins. PMID:25638406

  15. Use of Cystatin C and Serum Creatinine for the Diagnosis of Contrast-Induced Nephropathy in Patients Undergoing Contrast-Enhanced Computed Tomography at an Oncology Centre

    PubMed Central

    Fortalesa Melo, Joao Italo; Chojniak, Rubens; Costa Silva, Debora Helena; Oliveira Junior, Jose Carlos; Vieira Bitencourt, Almir Galvăo; Holanda Silva, Diego; Guimarăes, Marcos Duarte; Silva, Hernandes Cerqueira Souza; Dias, Denis Guilherme Teixeira; Rodrigues, Winglison Carli; Brancucci, Ellen Luzia; Cruz, Barbara Martins Soares; Schiavon, Beatriz Nunes; Argenton, Juliana Luz Passos; Camporini, Margareth Arrivabene; Zocchio, Adriana

    2015-01-01

    Objective Our aim was to assess renal function using as laboratory measurements serum creatinine and cystatin C concentrations before and after administration of low-osmolarity (nonionic) iodinated contrast medium in patients with cancer undergoing computed tomography (CT). Methods This prospective study included 400 oncologic outpatients. Serum creatinine and cystatin C concentrations were measured before and 72 h after contrast administration. Glomerular filtration rates (GFRs) were estimated using serum creatinine–based [Modification of Diet in Renal Disease (MDRD) and Cockroft-Gault and cystatin C based (Larsson) equations. Exploratory data analysis was performed. The nonparametric Wilcoxon test was used to compare pre and post contrast of test results and estimated clearance. The confidence interval used in the analysis was 95%. Results Compared with the pre-contrast values, the mean serum creatinine concentration was significantly higher and average GFRs estimated using MDRD and Cockcroft-Gault equations were significantly lower after the administration of contrast (p <0.001). It was also observed a significant increase after contrast in the concentration of Cystatin C (p = 0.015). In addition, a decrease in GFR estimated using the average Larsson (p = 0.021) was observed between time points. However, none of the patients presented clinically significant nephropathy. Conclusions Assessment using serum creatinine and cystatin C concentrations showed changes in renal function among patients with cancer undergoing contrast-enhanced CT examination in this study. No significant renal damage related to the use of low-osmolarity iodinated contrast medium of the type and dosage employed in this study was observed. This contrast medium is thus safe for use in patients with cancer. PMID:25961558

  16. Evaluation of creatinine, cystatin C and eGFR by different equations in professional cyclists during the Giro d'Italia 3-weeks stage race.

    PubMed

    Colombini, Alessandra; Corsetti, Roberto; Graziani, Rosa; Lombardi, Giovanni; Lanteri, Patrizia; Banfi, Giuseppe

    2012-04-01

    Abstract In this study, creatinine-based equations to evaluate glomerular filtration rate (eGFR) were proposed to more accurately assess kidney function, and cystatin C, a parameter not dependent on muscular mass, was introduced to improve GFR calculation in professional cyclists during a long-lasting race. Nine cyclists participating in the 2011 Giro d'Italia were recruited. Blood and anthropometrical data were collected the day before (T-1) the race, on the 12th day (T 12) and on the 22nd day (T 22) of the race. Haemoglobin and haematocrit were registered. Haemodilution was observed at T 12, whilst stabilization was evident at T 22. Creatinine, cystatin C concentrations and eGFR values were not modified during the observed period; only GFR evaluated with the Cockcroft-Gault (CG) formula and expressed as ml/min/1.73 m(2) significantly decreased (p < 0.05) at T 22 in comparison with T-1, probably as a consequence of weight decrease. Cystatin C levels were in the reference range, while creatinine concentrations were lower. The lowest eGFR values were observed with CG normalized and the Modification of Diet in Renal Disease (MDRD) formulas. A good correlation was observed between the MDRD and the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equations and between CG normalized and both CKD-EPI and MDRD formulas. The worst correlation was registered between CKD-EPI creatinine and cystatin C and all the other equations. In conclusion, adaptive mechanisms of renal function allow athletes to maintain stable creatinine, cystatin C and eGFR values during a long-lasting race. The use of GFR equations to evaluate general health status of sportsmen should be recommended with caution, considering also weight modification during competition. PMID:22201455

  17. Electron spin echo modulation study of sodium dodecyl sulfate and dodecyltrimethylammonium bromide micellar solutions in the presence of urea: Evidence for urea interaction at the micellar surface

    SciTech Connect

    Baglioni, P. (Univ. of Udine (Italy)); Ferroni, E. (Univ. of Florence (Italy)); Kevan, L. (Univ. of Houston, TX (USA))

    1990-05-17

    Electron spin echo studies have been carried out for a series of x-doxylstearic acid (x-DSA, x = 5,7,10,12,16) and 4-octanoyl-2,2,6,6-tetramethylpiperidine-1-oxy (C{sub 8}-TEMPO) spin probes in micellar solutions of anionic sodium dodecyl sulfate (SDS) and cationic dodecyltrimethylammonium bromide (DTAB) in D{sub 2}O and in the presence of 2 or 6 M urea or urea-d{sub 4}. Modulation effects due to the interaction of the unpaired electron with urea and water deuteriums show that urea does not affect the bent conformation of the x-DSA probe in the micelle. The analysis of the deuterium modulation depth and the Fourier transformation of the two-pulse electron spin echo spectra show that urea interacts with the surfactant polar headgroups at the micelle surface. These results support recent molecular dynamics and Monte Carlo calculations of micellar systems and are in agreement with direct interaction of urea at micellar surfaces in which it replaces some water molecules in the surface region.

  18. Urea-montmorillonite-extruded nanocomposites: a novel slow-release material.

    PubMed

    Pereira, Elaine I; Minussi, Fernando B; da Cruz, Camila C T; Bernardi, Alberto C C; Ribeiro, Caue

    2012-05-30

    The present study describes the preparation and characterization of a novel urea slow-release nanocomposite, based on urea intercalation into montmorillonite clay by an extrusion process at room temperature. Nanocomposites with urea contents ranging from 50 to 80 wt % were successfully produced and characterized. Analyses by XRD, DTA, and SEM-EDX confirmed the effectiveness of this simple process to exfoliate the clay lamellae into the urea matrix, forming a product that can be classified as a nanocomposite, due to the exfoliation degree attained. Diametral compression tests showed that the samples were very deformable, and the release rate of active components in water showed that the nanocomposite showed a slow release behavior for urea dissolution, even in low montmorillonite amounts (20% in weight). PMID:22574809

  19. Population-specific serum creatinine centiles in neonates with posterior urethral valves already predict long-term renal outcome.

    PubMed

    Lemmens, An-Sofie; Mekahli, Djalila; Devlieger, Roland; Levtchenko, Elena; Allegaert, Karel

    2014-07-28

    Abstract Introduction: The lowest serum creatinine (nadir Scr, cut-off 1?mg/dl) during infancy predicts subsequent renal outcome in posterior urethral valve (PUV) infants, but early, neonatal values may be useful to guide care. We aimed to explore correlations between neonatal Scr values and long-term renal outcome. Methods: Retrospective evaluation of records of 39 PUV patients, treated in the University Hospitals Leuven (2001-2011). Scr measurements were collected and associations (Mann-Whitney U, Spearman) to predict unfavorable renal outcome [GFR <60?ml/min/1.73?m(2) at 2 years] were explored. Results: Unfavorable renal outcome at the last follow-up was observed in 7/36 patients (19%). Besides the nadir Scr at a median age of 5 months, also the peak Scr and Scr between days 9 and 42 correlated significantly with renal outcome. By introducing "centiles" for neonatal Scr values in this PUV cohort, the 75th Scr percentile in this PUV cohort was highly predictive for unfavorable renal outcome. Conclusions: Besides the nadir Scr, early neonatal Scr values (peak, days 9-42, PUV cohort-specific 75th centile) also predicted unfavorable renal outcome. The introduction of PUV disease specific reference Scr centiles may be helpful to facilitate earlier prediction and guide counseling, but necessitates external validation. PMID:25000449

  20. Serum creatinine concentration in very-low-birth-weight infants from birth to 34–36?wk postmenstrual age

    PubMed Central

    Bateman, David A.; Thomas, William; Parravicini, Elvira; Polesana, Elena; Locatelli, Chiara; Lorenz, John M.

    2015-01-01

    Background: Serum creatinine (s[Cr]) reference ranges for very-low-birth-weight (VLBW) infants must account for physiologic changes in the first months of life. Methods: We retrospectively identified a sample of 218 appropriate-for-gestational age (GA) VLBW infants without risk factors for renal impairment, and classified into one of three GA groups: 25–27, 28–29, and 30–33?wk. We observed three phases of s[Cr] change (initial, decline, and equilibrium), whose characteristics varied by GA group. We used mixed-effects regression models to estimate mean and upper 95th prediction interval of s[Cr] for each GA group from birth to 34–36?wk post menstrual age (PMA). Results: In phase I, s[Cr] increased after birth, then returned slowly to baseline. The duration of phase I and the magnitude of s[Cr] rise decreased with increasing GA. In phase II, s[Cr] declined abruptly at a rate that increased with GA. A gradual transition to phase III, a steady-state equilibrium with similar s[Cr] among GA groups, began at approximately 34–36?wk PMA. We constructed GA group-specific nomograms depicting s[Cr] behaviour across the three phases. Conclusion: The reference ranges derived from a sample of infants without risk factors for renal impairment provide a context for quantitative interpretation of s[Cr] trends in VLBW infants. PMID:25675426