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Sample records for urea creatinine uric

  1. 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.

  2. Creatinine

    MedlinePLUS

    ... helpful? Also known as: Creat; Blood Creatinine; Serum Creatinine; Urine Creatinine Formal name: Creatinine Related tests: BUN ; BUN/ ... Panel ; Basic Metabolic Panel ; Urinalysis ; Urine Protein to Creatinine Ratio ; Urine Albumin and Urine Albumin/Creatinine Ratio ; Renal Panel ; ...

  3. Creatinine

    MedlinePLUS

    ... then passes out of the body in your urine. If you have kidney disease, the level of creatinine in your blood increases. Blood (serum) and urine tests can check your creatinine levels. The tests ...

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

    PubMed

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

    2014-04-01

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

  5. Spectroscopic and structural study of the newly synthesized heteroligand complex of copper with creatinine and urea.

    PubMed

    Gangopadhyay, Debraj; Singh, Sachin Kumar; Sharma, Poornima; Mishra, Hirdyesh; Unnikrishnan, V K; Singh, Bachcha; Singh, Ranjan K

    2016-02-01

    Study of copper complex of creatinine and urea is very important in life science and medicine. In this paper, spectroscopic and structural study of a newly synthesized heteroligand complex of copper with creatinine and urea has been discussed. Structural studies have been carried out using DFT calculations and spectroscopic analyses were carried out by FT-IR, Raman, UV-vis absorption and fluorescence techniques. The copper complex of creatinine and the heteroligand complex were found to have much increased water solubility as compared to pure creatinine. The analysis of FT-IR and Raman spectra helps to understand the coordination properties of the two ligands and to determine the probable structure of the heteroligand complex. The LIBS spectra of the heteroligand complex reveal that the complex is free from other metal impurities. UV-visible absorption spectra and the fluorescence emission spectra of the aqueous solution of Cu-Crn-urea heteroligand complex at different solute concentrations have been analyzed and the complex is found to be rigid and stable in its monomeric form at very low concentrations. PMID:26529636

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

    PubMed Central

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

    2012-01-01

    This study was carried out to investigate the effect of Aloe vera extract (AvE) on serum electrolytes, urea, and creatinine as indices of renal function in Sprague-Dawley rats. Twelve male Sprague-Dawley rats weighing between 80 and 130 g were used. Rats were divided into two groups: The control and the test groups (n=6). The test group received 1 ml of AvE daily for 28 days. Both the groups fed on standard rat chow and water ad libitum. The results showed a decrease in serum levels of sodium, and potassium, but an increase in the serum levels of bicarbonate, urea, and creatinine in the test group. The changes seen were, however, statistically insignificant, except for the serum levels of sodium and creatinine (P<0.05). It is thus concluded that AvE impairs renal handling of electrolytes with consequent hyponatremia and hypercreatinemia. However, this might be of therapeutic value in conditions associated with hypernatremia. PMID:22754258

  7. Creatinine and urea biosensors based on a novel ammonium ion-selective copper-polyaniline nano-composite.

    PubMed

    Zhybak, M; Beni, V; Vagin, M Y; Dempsey, E; Turner, A P F; Korpan, Y

    2016-03-15

    The use of a novel ammonium ion-specific copper-polyaniline nano-composite as transducer for hydrolase-based biosensors is proposed. In this work, a combination of creatinine deaminase and urease has been chosen as a model system to demonstrate the construction of urea and creatinine biosensors to illustrate the principle. Immobilisation of enzymes was shown to be a crucial step in the development of the biosensors; the use of glycerol and lactitol as stabilisers resulted in a significant improvement, especially in the case of the creatinine, of the operational stability of the biosensors (from few hours to at least 3 days). The developed biosensors exhibited high selectivity towards creatinine and urea. The sensitivity was found to be 85±3.4mAM(-1)cm(-2) for the creatinine biosensor and 112±3.36mAM(-1)cm(-2) for the urea biosensor, with apparent Michaelis-Menten constants (KM,app), obtained from the creatinine and urea calibration curves, of 0.163mM for creatinine deaminase and 0.139mM for urease, respectively. The biosensors responded linearly over the concentration range 1-125µM, with a limit of detection of 0.5µM and a response time of 15s. The performance of the biosensors in a real sample matrix, serum, was evaluated and a good correlation with standard spectrophotometric clinical laboratory techniques was found. PMID:26457736

  8. 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

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

    PubMed

    Risch, Lorenz; Hess, Bernhard

    2013-08-01

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

  10. Relationship of serum uric acid, serum creatinine and serum cystatin C with maternal and fetal outcomes in rural Indian pregnant women

    PubMed Central

    Yalamati, Padma; Bhongir, Aparna Varma; Betha, Kalpana; Verma, Ritika; Dandge, Shailendra

    2015-01-01

    Background Hypertensive disorders are the most common in pregnancy. Several studies showed a positive correlation between elevated maternal serum uric acid (UA), serum creatinine and adverse maternal and fetal outcomes, but only a few studies are available on serum cystatin C and maternal and fetal outcomes. The present study was undertaken to study the association of serum UA, creatinine and cystatin C with maternal and fetal outcomes. Methods Out of 116 pregnant women 69 women had no hypertension and 47 had hypertension with or without proteinuria. Serum UA, creatinine and cystatin C was measured by modified Uricase method, modified kinetic Jaffe’s reaction and particle-enhanced immunonephelometric assay respectively. Multivariate logistic regression was performed to determine the independent effects of serum UA, creatinine and cystatin C on maternal and fetal outcomes using stata 13.1. Results The adjusted odds ratio (OR) was 3.73 (95% CI: 1.18-11.75; P=0.024) for UA; 15.79 (95% CI: 3.04-81.94; P=0.001) for creatinine and 2.03 (95% CI: 0.70-5.87; P=0.192) for cystatin C in hypertensive disorders of pregnancy. All the three renal parameters were not significantly associated with birth weight, gestational age of delivery and mode of delivery after adjusting for the confounding factors. Conclusions Serum creatinine and uric acid are independent risk factors for hypertensive disorders of pregnancy. High serum uric acid is associated with low birth weight and delivery by caesarian section whereas high serum creatinine with preterm delivery only before adjustment for confounding factors and not after adjustment. Serum cystatin C was not significantly associated with the maternal and fetal outcomes.

  11. Animals excrete three main nitrogen products, ammonia, urea and uric acid (Fig. 1), as well as some minor nitrogen

    E-print Network

    Paiva, Paulo Cesar de

    Animals excrete three main nitrogen products, ammonia, urea and uric acid (Fig. 1), as well as some and amino acids. The term ammonia will be used to indicate the total ammonia, whereas NH3 and NH4 + will refer to non-ionic ammonia and ammonium ion, respectively. Whether an animal excretes predominantly

  12. 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

  13. Increased serum urea to creatinine ratio and its negative correlation with arterial pressure in canine babesiosis.

    PubMed

    Zygner, Wojciech; Gójska-Zygner, Olga

    2014-09-01

    The increase of the serum urea to creatinine ratio (UCR) was observed in dogs infected with Babesia canis. Previous studies have suggested that decrease of blood pressure can be one of the reasons for this phenomenon. In this work statistically significant increase of the UCR was observed in dogs with babesiosis. Comparison of the UCR between 23 azotaemic dogs and 25 non-azotaemic dogs infected with Babesia canis showed statistically significantly higher mean of the UCR in azotaemic dogs. Correlations between UCR and systolic, diastolic and mean arterial pressure (SAP, DAP and MAP) in 48 dogs infected with B. canis were negative (UCR and SAP: r = -0.3909; UCR and DAP: r = -0.3182; UCR and MAP: r = -0.3682) and statistically significant (p < 0.05). This result may indicate contribution of hypotension in the increase of the UCR in canine babesiosis. However, the correlations were not high, and there was no statistically significant correlation between UCR and arterial pressures in azotaemic dogs. Thus, it seems that decrease of blood pressure in dogs with babesiosis explains only partially the cause of increased UCR in infected dogs. The other authors suggested hyperureagenesis and myocardial injury as a potential reason for the increased UCR in canine babesiosis. Thus, further studies are needed to determine causes of increased UCR in dogs with babesiosis, especially on the connection between UCR changes and the concentrations of plasma cardiac troponins and ammonia, and the occurrence of occult blood on fecal examination. PMID:25119372

  14. A multi-functional electrochemical sensing system using microfluidic technology for the detection of urea and creatinine.

    PubMed

    Huang, Chao-June; Lin, Jiun-Lin; Chen, Ping-Hong; Syu, Mei-Jywan; Lee, Gwo-Bin

    2011-04-01

    This study presents a new microfluidic system capable of precise measurements of two important biomarkers, urea and creatinine, automatically. In clinical applications, high levels of these two biomarkers are early indicators of nephropathy or renal failure and should be monitored on a regular basis. The microfluidic system is composed of a microfluidic chip, a control circuit system, a compressed air source and several electromagnetic valves to form a handheld system. The microfluidic chip is fabricated by using micro-electromechanical systems and microfluidic techniques comprising electrochemical sensor arrays and polydimethylsiloxane-based microfluidic structures such as micropumps/micromixers, normally closed valves and microchannels. The microfluidic system performs a variety of critical processes including sample pretreatment, mixing, transportation and detection on a single chip. The experimental results show that the entire procedure takes approximately 40 min, which is much faster than the traditional method (more than 6 h). Furthermore, the total sample volume consumed in each operation is only 0.1 mL, which is significantly less than that required in a large system (5 mL). The developed automatic microfluidic system may provide a powerful platform for further clinical applications. PMID:21437917

  15. 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

  16. Serologic Investigation of Hantavirus Infection in Patients with Previous Thrombocytopenia, and Elevated Urea and Creatinine Levels in an Epidemic Region of Turkey.

    PubMed

    Sevencan, Funda; Gözalan, Aysegül; Uyar, Yavuz; Kavakli, Ismet; Türkyilmaz, Bedia; Ertek, Mustafa; Lundkvist, Ake

    2015-11-20

    The first cases of Hantavirus infection in Turkey were reported in early 2009 in the Zonguldak and Bartin provinces. The aim of this study was to investigate the presence of Hantavirus antibodies in patients who had clinical and laboratory findings that were potentially associated with Hantavirus infection prior to the epidemic in Bartin in 2009. After screening 314,577 medical records from between 2007 and 2009, the clinical and laboratory data for 442 patients meeting the criteria of coexistent thrombocytopenia, and elevated urea and creatinine levels were transferred to a statistical program. Home visits were made to 170 patients, 84 of whom consented to participate in the study. The participants completed a questionnaire and provided a blood sample. Commercial anti-Hantavirus IgG and IgM ELISA and immunoblotting assays were used, with seropositive samples being confirmed by focus reduction neutralization tests (FRNT). ELISA and/or immunoblotting assays detected 10 positive samples; however, only 7 of these were recorded as positive by FRNT. FRNT positivity was significantly associated with female sex, the presence of a barn near to the house, and working in a forest (P < 0.05). In a Hantavirus endemic region, physicians must keep in mind that thrombocytopenia, and elevated urea and creatinine levels may indicate Hantavirus infection. PMID:25866109

  17. Urea

    Integrated Risk Information System (IRIS)

    Urea ; CASRN : 57 - 13 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects ) a

  18. Creatinine - urine

    MedlinePLUS

    Urine creatinine test ... Urine creatinine (24-hour sample) values can range from 500 to 2000 mg/day. Results depend on your ... Abnormal results of urine creatinine may be due to any of the following: High meat diet Kidney problems, such as damage to the tubule ...

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

  20. Creatinine clearance test

    MedlinePLUS

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

  1. Creatinine blood test

    MedlinePLUS

    ... work. Creatinine can also be measured with a urine test . ... increases in your blood. This is because less creatinine is released through your urine. The creatinine level also varies according to a ...

  2. Uric acid test (image)

    MedlinePLUS

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

  3. Uric acid - blood

    MedlinePLUS

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

  4. Uric Acid Test

    MedlinePLUS

    ... limited. Home Visit Global Sites Search Help? Uric Acid Share this page: Was this page helpful? Also known as: Serum Urate; UA Formal name: Uric Acid Related tests: Synovial Fluid Analysis , Kidney Stone Analysis , ...

  5. Spreadsheet Use to Calculate Creatinine Clearance From Serum Creatinine

    PubMed Central

    Shrewsberry, Timothy W.; Banoub, Ashraf; Fleming, Kevin; Snyder, Holly; Stehlik, James

    2007-01-01

    Abstract: Spreadsheets may be created to include the Cockcroft-Gault Formula (CGF) for creatinine-based estimation of glomerular filtration rate. Creatinine clearance (CrCl) provides a more accurate method for perioperative risk assessment of renal function than serum creatinine. CrCl may be used to develop guidelines for renal protective management strategies during cardiopulmonary bypass. CGF uses serum creatinine, age, kilogram weight, sex, and “logical test” functions within the spreadsheet to calculate the CrCl. Implementation of spreadsheets has the potential for numerous other calculations and may provide an accurate and consistent method of clinical perfusion management. PMID:18293814

  6. 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.

  7. Urine Albumin and Albumin/ Creatinine Ratio

    MedlinePLUS

    ... Albumin; Albumin-to-Creatinine Ratio Related tests: Albumin ; Creatinine ; Glucose ; A1c ; Urine Protein ; Beta-2 Microglobulin All content on Lab ... urine ). Most of the time, both albumin and creatinine are measured in a random urine sample and an albumin/creatinine ratio (ACR) is ...

  8. Approach to managing elevated creatinine.

    PubMed Central

    Tremblay, Richard

    2004-01-01

    OBJECTIVE: To describe a systematic approach to finding the underlying cause of an elevated creatinine level. QUALITY OF EVIDENCE: This diagnostic approach is based on a synthesis of information from reference works on nephrology, articles found through a MEDLINE search, and the author's personal experience. MAIN MESSAGE: Elevated creatinine levels suggest the differential diagnosis of renal failure (RF). History and a complete physical examination are important, keeping in mind that RF is often asymptomatic in the early stages. After repeating the creatinine test to verify results, baseline tests should be ordered to identify the cause of the RF. Comparing results of serial tests is essential for determining whether RF is acute or chronic, stable or progressive. An ultrasound scan is particularly useful for eliminating an obstructive cause; the size of the kidney can indicate whether disease is acute or chronic. Complementary blood tests and imaging studies might be useful. CONCLUSION: Diagnosing and managing RF can appear complex, but a systematic approach will help you find the cause and treat the condition. PMID:15171676

  9. A creatinine biosensor based on admittance measurement

    NASA Astrophysics Data System (ADS)

    Ching, Congo Tak-Shing; Sun, Tai-Ping; Jheng, Deng-Yun; Tsai, Hou-Wei; Shieh, Hsiu-Li

    2015-08-01

    Regular check of blood creatinine level is very important as it is a measurement of renal function. Therefore, the objective of this study is to develop a simple and reliable creatinine biosensor based on admittance measurement for precise determination of creatinine. The creatinine biosensor was fabricated with creatinine deiminase immobilized on screen-printed carbon electrodes. Admittance measurement at a specific frequency ranges (22.80 - 84.71 Hz) showed that the biosensor has an excellent linear (r2 > 0.95) response range (50 - 250 uM), which covers the normal physiological and pathological ranges of blood creatinine levels. Intraclass correlation coefficient (ICC) showed that the biosensor has excellent reliability and validity (ICC = 0.98). In conclusion, a simple and reliable creatinine biosensor was developed and it is capable of precisely determining blood creatinine levels in both the normal physiological and pathological ranges.

  10. Metabolomics insights into chronic kidney disease and modulatory effect of rhubarb against tubulointerstitial fibrosis

    E-print Network

    2015-01-01

    to creatinine. Creatinine is excreted in the urine andcreatinine (CREA), urea, uric acid (UA), phosphorus (P), potassium (K + ) and urineurine creatine, dimethylglycine and glyceric acid as well as significant reduction of creatinine,

  11. [Predictability of creatinine clearance from serum creatinine in chronic glomerulonephritis].

    PubMed

    Shoji, T; Hayashi, T; Kitamura, E; Okada, N; Nakanishi, I; Tsubakihara, Y

    1993-03-01

    We evaluated the formulas of urine-free prediction of creatinine clearance (CCr) for clinical use in the patients with chronic glomerulonephritis (CGN). Subjects were 246 patients with CGN diagnosed by renal biopsy with range from normal renal function to end stage renal failure. CCr were measured exactly with urine collections more than 2 times and compared with the values calculated using four urine-free mathematical formulas of Cockcroft et al, Mawer et al, Konishi et al, and Tozune et al. Strong, statistically significant correlations were observed between CCr estimated with each prediction method and measured CCr (r > or = 0.946). However, the latter two formulas tended to overestimate the values. Predicted errors more than 20% of the formula of Cockcroft et al, were the least. And their formula was the easiest for clinical use because of the simplicity for learning by heart. We conclude that these four formulas can be used with reasonable accuracy in the patients with CGN from normal renal function to end stage renal failure, and the formula of Cockcroft et al, is the most recommendable for clinical use. PMID:8501859

  12. 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 1.15 mg/dL, with no significant differences between blood samples taken from different parts of the body. The blood creatinine level was stable for 3 days 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

  13. 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.

  14. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....1225 Creatinine test system. (a) Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Creatinine test system. 862.1225 Section...

  15. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ....1225 Creatinine test system. (a) Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Creatinine test system. 862.1225 Section...

  16. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ....1225 Creatinine test system. (a) Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Creatinine test system. 862.1225 Section...

  17. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....1225 Creatinine test system. (a) Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Creatinine test system. 862.1225 Section...

  18. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ....1225 Creatinine test system. (a) Identification. A creatinine test system is a device intended to measure creatinine levels in plasma and urine. Creatinine measurements are used in the diagnosis and... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Creatinine test system. 862.1225 Section...

  19. Type 2 Diabetes and Uric Acid Nephrolithiasis

    NASA Astrophysics Data System (ADS)

    Maalouf, Naim M.

    2008-09-01

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

  20. Urea transport by cotransporters.

    PubMed

    Leung, D W; Loo, D D; Hirayama, B A; Zeuthen, T; Wright, E M

    2000-10-15

    The rabbit Na+-glucose cotransporter (rbSGLT1) was expressed in Xenopus laevis oocytes and urea transport in rbSGLT1 and non-injected (control) oocytes was studied using [14C]urea as a tracer. The level of rbSGLT1 expression in these batches of oocytes was monitored by measuring the uptake of alpha-methyl-D-[14C]glucopyranoside ([14C]alphaMDG). In rbSGLT1-expressing oocytes, there was a 4-fold increase in urea transport in the absence of sugar relative to that in control oocytes. Urea uptake was not Na+ dependent and was linear with both time of incubation (5-120 min) and increasing urea concentration (50 microM to 100 mM) in the bathing medium. rbSGLT1 urea uptake was blocked by the rbSGLT1-specific inhibitor phlorizin (Ki 1 microM) in 100 mM NaCl buffer, but was not affected in 100 mM choline chloride buffer. Phloretin inhibited rbSGLT1 urea uptake with a low affinity (Ki > 1 mM) in the presence and absence of Na+. The uptake of 55 m[mu]M urea through rbSGLT1 was not blocked by 100 mM urea analogues including thiourea, 1,3-dimethyl urea, 1,1-dimethyl urea and acetamide. The activation energies (Ea) of urea transport for control and rbSGLT1-expressing oocytes were 14+/-3 and 6+/-1 kcal mol(-1), respectively. The low Ea for urea transport through rbSGLT1 is comparable to the Ea of passive water transport through rbSGLT1. Urea transport through rbSGLT1 was further increased when the cotransporter was activated by the addition of sugar to the external medium. The rate of sugar-dependent urea uptake was directly proportional to the rate of Na+-glucose-H2O cotransport such that the amount of urea transport was approximately proportional to the molar concentration ratio of urea to H2O (55 microM/55 M). The low affinity Na+-glucose (pSGLT3), the Na+-iodide (rNIS) and the Na+-(Cl-)-GABA (hGAT1) cotransporters expressed in oocytes demonstrated similar urea transport properties. These observations suggest that cotransporters behave as urea channels in the absence of substrates. Furthermore, under substrate-transporting conditions, the same cotransporters serve as urea cotransporters. This could account for urea transport in cells that appear not to have urea uniporters or channels. PMID:11034615

  1. 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)

  2. 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

  3. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Uric acid test system. 862.1775 Section 862.1775....1775 Uric acid test system. (a) Identification. A uric acid test system is a device intended to measure uric acid in serum, plasma, and urine. Measurements obtained by this device are used in the...

  4. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Uric acid test system. 862.1775 Section 862.1775....1775 Uric acid test system. (a) Identification. A uric acid test system is a device intended to measure uric acid in serum, plasma, and urine. Measurements obtained by this device are used in the...

  5. 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

  6. 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

  7. Plasma exogenous creatinine clearance in clinically healthy cats: comparison with urinary exogenous creatinine clearance, tentative reference intervals and indexation to bodyweight.

    PubMed

    Reynolds, B S; Massal, M R; Nguyen, P; Grégoire, L L; Périgaud, A E; Concordet, D; Biourge, V; Lefebvre, H P

    2014-10-01

    Glomerular filtration rate (GFR) is considered to be the best indicator of overall kidney function. The major objectives of this study were to compare plasma exogenous creatinine clearance (PECC) with a reference method, to establish reference intervals (RIs) for PECC and to assess the effects of indexation of GFR to bodyweight (BW) in cats. PECC was compared with urinary clearance of exogenous creatinine (UECC) in six clinically healthy domestic shorthair cats (experiment 1). Tentative RIs were determined according to current guidelines and the effects of indexation to BW and of covariables on GFR were assessed in 43 clinically healthy cats of various breeds (experiment 2). PECC was 15% higher than UECC (P?<0.01), but the two estimates were strongly correlated (r(2)=0.97, P?=?0.001). RIs for PECC were 6.4-21.3?mL/min or 1.2-4.9?mL/min/kg. The absolute (i.e. non-indexed) GFR value was not dependent on BW. Thus, indexation of GFR to BW in cats would not standardize the GFR value, but could introduce bias in clinical interpretation. Significant effects of breed, plasma protein concentration and plasma albumin concentration on GFR were demonstrated. Plasma concentrations of urea and creatinine, when assessed separately, were also weakly correlated with GFR in healthy cats. These combined findings contribute to a better understanding of renal function assessment in cats. PMID:25193408

  8. Reduction of urinary uric acid excretion in patients with proteinuria.

    PubMed

    Zou, Huiqing; Xiang, Mingfeng; Ye, Xinming; Xiong, Yuanzhen; Xie, Baogang; Shao, Jianghua

    2015-12-01

    Serum uric acid (UA) concentration is positively associated with proteinuria. However, the relationship between proteinuria and urinary metabolites of purine metabolism remains unknown. This study developed a hydrophilic interaction chromatography (HILIC)-based HPLC method with ultraviolet detection (UV) to quantify creatinine (Cr), UA, xanthine, and hypoxanthine in human urine simultaneously. The urinary concentrations of UA and Cr obtained by our method are consistent with those measured by an autoanalyzer. The HPLC-HILIC-UV method was validated as selective and robust with simple sample preparation for measuring UA, xanthine, hypoxanthine and Cr, which is suitable for large clinical studies. The UA/Cr ratios in random urine samples were 5.5 times lower in proteinuria patients (0.077±0.008) than in healthy individuals (0.424±0.037). Moreover, the UA/hypoxanthine ratio in proteinuria patients was approximately 10 times lower than that in healthy individuals. Our findings revealed a reduced urinary UA excretion, which is one of the factors leading to increased serum UA in proteinuria patients. PMID:26523664

  9. Uric acid in the etiology of psoriasis.

    PubMed

    Goldman, M

    1981-01-01

    The potential etiologic relationship between uric acid in its microcrystalline monosodium urate form and psoriasis was examined by 1) substantiating the reported correlation between hyperuricemia and psoriasis using the phosphotungstate method; 2) examining psoriatic tissue samples for the presence of urates under a microscope using polarized light and a compensator; 3) attempting to induce psoriasis-like symptoms in laboratory animals with purine-to-uric acid metabolism by increasing serum uric acid level; and 4) observing psoriasis-hyperuricemic patients following treatment for their hyperuricemia with Allopurinol. As expected, both men and women psoriatics had higher uric acid levels than did their counterparts in a control group. Monosodium urate crystals were found in samples from psoriatic plaques by both methods used. They were clustered particularly around sweat pores and Munro abscesses, but were found only occasionally in epidermal tissue taken from nonpsoriatics. Psoriasis-like symptoms were induced in laboratory animals (the South American boa, Constrictor constrictor) when they were fed doses of uric acid. Patients with psoriasis and hyperuricemia showed marked improvement in psoriasis when treated for their hyperuricemia. Psoriasis, like gout, may be, at least partly, a result of disorder of purine metabolism and monosodium urate crystals may be responsible for the cell proliferation that is characteristic of psoriatic plaques. Monosodium urate crystals were found by the author to be strikingly segmented. This structure may result in ease of fragmentation, thus increasing the difficulty in identifying urates in any tissue. PMID:7337193

  10. Uric acid deposits in symbiotic marine algae.

    PubMed

    Clode, Peta L; Saunders, Martin; Maker, Garth; Ludwig, Martha; Atkins, Craig A

    2009-02-01

    The symbiosis between cnidarians and dinoflagellate algae is not understood at the cell or molecular level, yet this relationship is responsible for the formation of thousands of square kilometres of coral reefs. We have investigated the nature of crystalline material prominent within marine algal symbionts of Aiptasia sp. anemones. This material, which has historically been considered to be calcium oxalate, is shown to be uric acid. We demonstrate that these abundant uric acid stores can be mobilized rapidly, thereby allowing the algal symbionts to flourish in an otherwise N-poor environment. This is the first report of uric acid accumulation by symbiotic marine algae. These data provide new insight and considerations for understanding the physiological basis of algal symbioses, and represent a new and previously unconsidered aspect of N metabolism in cnidarian, and a variety of other, marine symbioses. PMID:19021889

  11. Uric acid protects erythrocytes from ozone-induced changes

    SciTech Connect

    Meadows, J.; Smith, R.C.

    1987-08-01

    Uric acid effectively reduced hemolysis and methemoglobin formation in bovine and swine erythrocytes bubbled with ozone in vitro. In bovine erythrocytes, formation of thiobarbituric acid-reactive material was inhibited by uric acid, but there was little immediate protection for the swine cells. Antioxidant protection was due to preferential degradation of the uric acid by ozone. These results provide evidence to support the hypothesis that in plasma, uric acid can provide antioxidant protection for erythrocytes.

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

    NASA Astrophysics Data System (ADS)

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

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

  13. RESPONSE TO COMMENTARIES On Arsenic, Diabetes, Creatinine, and Multiple Regression

    E-print Network

    California at Berkeley, University of

    . Adjustment for creatinine is done to account for urine dilution, but there is an expanding body of literature­2006, for example, the range in urine creatinine concentrations was over 100-fold (7­768 mg/dL)--well beyond any. In addition, arsenic and creatinine concentrations in urine have been found to be correlated, even after

  14. 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.

  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. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...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....

  17. 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....

  18. 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....

  19. 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

  20. Urine Protein and Urine Protein to Creatinine Ratio

    MedlinePLUS

    ... Visit Global Sites Search Help? Urine Protein and Urine Protein to Creatinine Ratio Share this page: Was this page helpful? ... Urine Protein; Urine Total Protein; Urine Protein to Creatinine Ratio; UPCR Formal name: Urine Protein Related tests: Urinalysis ; Albumin ; Microalbumin ; Protein Electrophoresis ; ...

  1. Increasing the sensitivity of the Jaffe reaction for creatinine

    NASA Technical Reports Server (NTRS)

    Tom, H. Y.

    1973-01-01

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

  2. 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.

  3. Uric Acid Levels in Normotensive Children of Hypertensive Parents

    PubMed Central

    Yildirim, Ali; Keles, Fatma; Kosger, Pelin; Ozdemir, Gokmen; Ucar, Birsen; Kilic, Zubeyir

    2015-01-01

    This study evaluated uric acid concentrations in normotensive children of parents with hypertension. Eighty normotensive children from families with and without a history of essential hypertension were included. Concentrations of lipid parameters and uric acid were compared. Demographic and anthropometric characteristics were similar in the groups. Systolic and diastolic blood pressure were higher in the normotensive children of parents with hypertension without statistically significant difference (P > 0.05). Uric acid concentrations were higher in the normotensive children of parents with hypertension (4.61 versus 3.57?mg/dL, P < 0.01). Total cholesterol and triglyceride concentrations were similar in the two groups. Systolic and diastolic blood pressure were significantly higher in control children aged >10 years (P < 0.01). Uric acid levels were significantly higher in all children with more pronounced difference after age 10 of years (P < 0.001). Positive correlations were found between the level of serum uric acid and age, body weight, body mass index, and systolic and diastolic blood pressure in the normotensive children of parents. The higher uric acid levels in the normotensive children of hypertensive parents suggest that uric acid may be a predeterminant of hypertension. Monitoring of uric acid levels in these children may allow for prevention or earlier treatment of future hypertension. PMID:26464873

  4. Ancient insights into uric acid metabolism in primates

    E-print Network

    Chang, Belinda

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

  5. Natural history of elevated creatinine levels

    PubMed Central

    Marcotte, Laura; Godwin, Marshall

    2006-01-01

    OBJECTIVE To investigate what happens to the serum creatinine (SC) levels of people with initial mild elevations in SC; whether a stable, non-progressive elevation in SC level is the most common scenario; how common a progressive increase in SC is among primary care patients; and how often primary care patients with substantial elevations in SC (>300 ?mol/L) progress to end-stage renal disease. DESIGN Retrospective analysis of laboratory data and chart review. SETTING Queen’s University Family Medicine Centre in Kingston, Ont. PARTICIPANTS All patients who had SC levels measured at a nearby hospital laboratory between January 1994 and December 1998. MAIN OUTCOME MEASURES Recently recorded height and weight measurements, latest SC measurements (if available), whether patients had been referred to nephrologists, comorbidity, medications being taken, whether patients were currently undergoing dialysis or had received a renal transplant, and whether patients had died. RESULTS In the 1434 charts of eligible patients, 64 (4.5%) had elevated initial SC levels (>130 ?mol/L) recorded, and 57 of these contained follow-up SC levels also. Among these 57 patients, 32 (56%) saw their SC levels return to normal, including 50% of those whose initial levels had been >300 ?mol/L. Only 7 patients (12%) with elevated SC levels progressed to higher levels during the follow-up period. Average age in the study group was 63 years; those with initial elevated SC levels were older than the average (70 years). CONCLUSION More than half of those with initially elevated SC levels (>130 ?mol/L) saw their levels return to normal, including patients whose initial levels had been >300 ?mol/L. It seems that a single elevated SC measurement does not predict ongoing decline in renal function. PMID:17279186

  6. Uric Acid and Cardiovascular Events: A Mendelian Randomization Study.

    PubMed

    Kleber, Marcus E; Delgado, Graciela; Grammer, Tanja B; Silbernagel, Günther; Huang, Jie; Krämer, Bernhard K; Ritz, Eberhard; März, Winfried

    2015-11-01

    Obesity and diets rich in uric acid-raising components appear to account for the increased prevalence of hyperuricemia in Westernized populations. Prevalence rates of hypertension, diabetes mellitus, CKD, and cardiovascular disease are also increasing. We used Mendelian randomization to examine whether uric acid is an independent and causal cardiovascular risk factor. Serum uric acid was measured in 3315 patients of the Ludwigshafen Risk and Cardiovascular Health Study. We calculated a weighted genetic risk score (GRS) for uric acid concentration based on eight uric acid-regulating single nucleotide polymorphisms. Causal odds ratios and causal hazard ratios (HRs) were calculated using a two-stage regression estimate with the GRS as the instrumental variable to examine associations with cardiometabolic phenotypes (cross-sectional) and mortality (prospectively) by logistic regression and Cox regression, respectively. Our GRS was not consistently associated with any biochemical marker except for uric acid, arguing against pleiotropy. Uric acid was associated with a range of prevalent diseases, including coronary artery disease. Uric acid and the GRS were both associated with cardiovascular death and sudden cardiac death. In a multivariate model adjusted for factors including medication, causal HRs corresponding to each 1-mg/dl increase in genetically predicted uric acid concentration were significant for cardiovascular death (HR, 1.77; 95% confidence interval, 1.12 to 2.81) and sudden cardiac death (HR, 2.41; 95% confidence interval, 1.16 to 5.00). These results suggest that high uric acid is causally related to adverse cardiovascular outcomes, especially sudden cardiac death. PMID:25788527

  7. 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

  8. Quantitative analysis of creatinine in urine by metalized nanostructured parylene

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

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

    USGS Publications Warehouse

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

    2000-01-01

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

  10. Automated measurement of urinary creatinine by multichannel kinetic spectrophotometry.

    PubMed

    Ohira, Shin-Ichi; Kirk, Andrea B; Dasgupta, Purnendu K

    2009-01-15

    Urinary creatinine analysis is required for clinical diagnosis, especially for evaluation of renal function. Creatinine adjustment is also widely used to estimate 24-h excretion from spot samples. Few convenient validated approaches are available for in-house creatinine measurement for small- to medium-scale studies. Here we apply the Jáffe reaction to creatinine determination with zone fluidic multichannel kinetic spectrophotometry. Diluted urine sample and reagent, alkaline picric acid, were mixed by a computer-programmed dispenser and rapidly delivered to a four-channel detection cell. The absorbance change was monitored by a flow-through light-emitting diode-photodiode-based detector. Validation results against high-performance liquid chromatography-ultraviolet (HPLC-UV)/mass spectrometry (MS) are presented. Responses for 10-fold diluted samples were linear within clinically relevant ranges (0-250 mg/L after dilution). The system can analyze 70 samples per hour with a limit of detection of 0.76 mg/L. The relative standard deviation was 1.29% at 100 mg/L creatinine (n=225). Correlation with the HPLC (UV quantitation/MS confirmation) system was excellent (linear, r2=0.9906). The developed system allows rapid, simple, cost-effective, and robust creatinine analysis and is suitable for the analysis of large numbers of urine samples. PMID:18977332

  11. Associations between blood pressure responses to acute stress and impaired renal function and serum uric acid level.

    PubMed

    Ohno, Sachi; Miyata, Masaaki; Kohjitani, Atsushi; Tohya, Akina; Ohishi, Mitsuru; Sugiyama, Kazuna

    2015-12-01

    The study aimed to examine correlations between blood pressure (BP) responses to direct laryngoscopy and tracheal intubation and parameters of renal function, serum uric acid (SUA) level, and mean preoperative BP. Fifty-four patients (?40 years) who were scheduled for oral surgery were analyzed. General anesthesia was induced by the rapid sequence method without opioid analgesics. Systolic and diastolic BP (SBP, DBP) in the operation room were measured when an electrocardiogram, a BP cuff, and a pulse oximetry probe were attached to the patients (T1) and immediately after the trachea was intubated (T2). The ?SBP was defined as the difference between SBP at T2 and T1. The increasing rate of SBP (?SBPr) was defined as ?SBP/SBP at T1. SBP at T2 was associated with increasing age (R?=?0.44), serum creatinine (R?=?0.32), SUA (R?=?0.30), mean preoperative SBP and DBP (R?=?0.54 and 0.37, respectively), and reduced estimated glomerular filtration rate (eGFR) (R?=?-0.44). Serum creatinine and SUA were positively associated, and eGFR was negatively associated with ?SBP (R?=?0.36, 0.34, and -0.29) and ?SBPr (R?=?0.39, 0.37, and -0.29). Multivariate regression analysis revealed that age and mean preoperative SBP was independently associated with SBP at T2, and serum creatinine was independently associated with ?SBP and ?SBPr. These findings suggested that elevated serum creatinine level, as well as elevated preoperative BP level, was associated with enhanced BP responses to acute stress in middle-aged to elderly patients. PMID:26114353

  12. [Gout in the past and uric arthritis today in Croatia] ].

    PubMed

    Cunovi?, S; Cunovi?-Dubroja, R

    2001-01-01

    In the past, gout was well known in these places, from Istria to Dubrovnik. Our very first dictionaries also witness about gout. Old doctors from Krapinske Toplice had also written about gout. Dr Edmund Mai, in his article published in "Lijecnicki vjesnik" in 1904 mentions "171 cases of uric arthritis". But, after that, for long 60 years there wasn't even a word about our patients, except surprise on very high incidence of the disease in the past. Even our handbooks had claimed that uric arthritis is not common in our country. In 1964 after 60 years of silence, the first article about our patients with uric arthritis, was published in "Lijecnicki vjesnik". These patients were medically treated for average of 13 years, and still were misdiagnosed. After that article, the numbers of patients with gout and articles on uric arthritis permanently rise. Today, the incidence of gout in Croatia is similar to that in other European countries. PMID:11845585

  13. 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....

  14. 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....

  15. SERS quantitative urine creatinine measurement of human subject

    NASA Astrophysics Data System (ADS)

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

    2005-03-01

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

  16. Classifying AKI by Urine Output versus Serum Creatinine Level.

    PubMed

    Kellum, John A; Sileanu, Florentina E; Murugan, Raghavan; Lucko, Nicole; Shaw, Andrew D; Clermont, Gilles

    2015-09-01

    Severity of AKI is determined by the magnitude of increase in serum creatinine level or decrease in urine output. However, patients manifesting both oliguria and azotemia and those in which these impairments are persistent are more likely to have worse disease. Thus, we investigated the relationship of AKI severity and duration across creatinine and urine output domains with the risk for RRT and likelihood of renal recovery and survival using a large, academic medical center database of critically ill patients. We analyzed electronic records from 32,045 patients treated between 2000 and 2008, of which 23,866 (74.5%) developed AKI. We classified patients by levels of serum creatinine and/or urine output according to Kidney Disease Improving Global Outcomes staging criteria for AKI. In-hospital mortality and RRT rates increased from 4.3% and 0%, respectively, for no AKI to 51.1% and 55.3%, respectively, when serum creatinine level and urine output both indicated stage 3 AKI. Both short- and long-term outcomes were worse when patients had any stage of AKI defined by both criteria. Duration of AKI was also a significant predictor of long-term outcomes irrespective of severity. We conclude that short- and long-term risk of death or RRT is greatest when patients meet both the serum creatinine level and urine output criteria for AKI and when these abnormalities persist. PMID:25568178

  17. Incidence and Risk Factors of Acute Kidney Injury after Radical Cystectomy: Importance of Preoperative Serum Uric Acid Level

    PubMed Central

    Joung, Kyoung-Woon; Choi, Seong-Soo; Kong, Yu-Gyeong; Yu, Jihion; Lim, Jinwook; Hwang, Jai-Hyun; Kim, Young-Kug

    2015-01-01

    Background: Acute kidney injury (AKI) is a common complication after surgery and increases costs, morbidity, and mortality of hospitalized patients. While radical cystectomy associates significantly with an increased risk of serious complications, including AKI, risk factors of AKI after radical cystectomy has not been reported. This study was performed to determine the incidence and independent predictors of AKI after radical cystectomy. Methods: All consecutive patients who underwent radical cystectomy in 2001-2013 in a single tertiary-care center were identified. Their demographics, laboratory values, and intraoperative data were recorded. Postoperative AKI was defined and staged according to the Acute Kidney Injury Network criteria on the basis of postoperative changes in creatinine levels. Independent predictors of AKI were identified by univariate and multivariate logistic regression analyses. Results: Of the 238 patients who met the eligibility criteria, 91 (38.2%) developed AKI. Univariate logistic regression analyses showed that male gender, high serum uric acid level, and long operation time associated with the development of AKI. On multivariate logistic regression analysis, preoperative serum uric acid concentration (odds ratio [OR] = 1.251; 95% confidence interval [CI] = 1.048-1.493; P = 0.013) and operation time (OR = 1.005; 95% CI = 1.002-1.008; P = 0.003) remained as independent predictors of AKI after radical cystectomy. Conclusions: AKI after radical cystectomy was a relatively common complication. Its independent risk factors were high preoperative serum uric acid concentration and long operation time. These observations can help to prevent AKI after radical cystectomy. PMID:26283877

  18. Chemiluminescence of creatinine/H2O2/Co(2+) and its application for selective creatinine detection.

    PubMed

    Hanif, Saima; John, Peter; Gao, Wenyue; Saqib, Muhammad; Qi, Liming; Xu, Guobao

    2016-01-15

    Creatinine is an important biomarker in clinical diagnosis and biomonitoring programs as well as urinary metabolomic/metabonomics research. Current methods are either nonselective, time consuming or require heavy and expensive instruments. In this study, chemiluminescence of creatinine with hydrogen peroxide has been reported for the first time, and its chemiluminescence is remarkably enhanced in the presence of cobalt ions. By utilizing these phenomena, we have developed a sensitive and selective chemiluminescence method for creatinine determination by coupling with flow injection analysis. The calibration curve is linear in the range of 1×10(-7)-3×10(-5)mol/L with a limit of detection (S/N=3) of 7.2×10(-8)mol/L, which is adequate for detecting creatinine in the clinically accepted range. The relative standard deviation for seven measurements of 3×10(-5)mol/L creatinine is 1.2%. The chemiluminescence method was then utilized to detect creatinine in human urine samples after simple dilution with water. It takes less than 1min each measurement and the recoveries for spiked urine samples were 100-103%. The interference study demonstrates that some common species in urine, such as amino acids, ascorbic acid and creatine, have negligible effects on creatinine detection. The present method does not use expensive instruments, enzymes and separation technique. This method has the advantages of sensitivity, selectivity, simplicity, rapidity, and low cost. It holds great promise for basic or comprehensive metabolic panel, drug screening, anti-dopping, and urinary metabolomic/metabonomics research. PMID:26339931

  19. National Urea Cycle Disorders Foundation

    MedlinePLUS

    ... urea cycle in regulating nitric oxide in the human body, the study is being conducted by Dr. ... a major discovery in ASA deficiency that transforms human science. The research has been published in Nature ...

  20. Critical Serum Creatinine Values in Very Preterm Newborns

    PubMed Central

    Bruel, Alexandra; Rozé, Jean-Christophe; Flamant, Cyril; Simeoni, Umberto; Roussey-Kesler, Gwenaëlle; Allain-Launay, Emma

    2013-01-01

    Background Renal failure in neonates is associated with an increased risk of mortality and morbidity. But critical values are not known. Objective To define critical values for serum creatinine levels by gestational age in preterm infants, as a predictive factor for mortality and morbidity. Study Design This was a retrospective study of all preterm infants born before 33 weeks of gestational age, hospitalized in Nantes University Hospital NICU between 2003 and 2009, with serum creatinine levels measured between postnatal days 3 to 30. Children were retrospectively randomized into either training or validation set. Critical creatinine values were defined within the training set as the 90th percentile values of highest serum creatinine (HSCr) in infants with optimal neurodevelopmental at two years of age. The relationship between these critical creatinine values and neonatal mortality, and non-optimal neural development at two years, was then assessed in the validation set. Results and Conclusion The analysis involved a total of 1,461 infants (gestational ages of 24-27 weeks (n=322), 28-29 weeks (n=336), and 30-32 weeks (803)), and 14,721 creatinine assessments. The critical values determined in the training set (n=485) were 1.6, 1.1 and 1.0 mg/dL for each gestational age group, respectively. In the validation set (n=976), a serum creatinine level above the critical value was significantly associated with neonatal mortality (Odds ratio: 8.55 (95% confidence interval: 4.23-17.28); p<0.01) after adjusting for known renal failure risk factors, and with non-optimal neurodevelopmental outcome at two years (odds ratio: 2.06 (95% confidence interval: 1.26-3.36); p=0.004) before adjustment. Creatinine values greater than 1.6, 1.1 and 1.0 mg/dL respectively at 24-27, 28-29, 30-32 weeks of gestation were associated with mortality before and after adjustment for risk factors, and with non-optimal neurodevelopmental outcome, before adjustment. PMID:24386431

  1. Renal transport of uric acid: evolving concepts and uncertainties.

    PubMed

    Bobulescu, Ion Alexandru; Moe, Orson W

    2012-11-01

    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 physiologic and pathophysiologic processes 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 about 90% of filtered urate and being responsible for 60% to 70% of total body uric acid excretion. Defective renal handling of urate is a frequent pathophysiologic factor underpinning hyperuricemia and gout. Despite 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 physiologic characteristics, importance in drug action, and genetic association with uric acid levels in human populations. The future may see the introduction of new drugs that act specifically on individual renal urate transporters for the treatment of hyperuricemia and gout. PMID:23089270

  2. Evaluating an alternative method for rapid urinary creatinine determination

    EPA Science Inventory

    Creatinine (CR) is an endogenously-produced chemical routinely assayed in urine specimens to assess kidney function, sample dilution. The industry-standard method for CR determination, known as the kinetic Jaffe (KJ) method, relies on an exponential rate of a colorimetric change,...

  3. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Creatinine test system. 862.1225 Section 862.1225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  4. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Creatinine test system. 862.1225 Section 862.1225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  5. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Creatinine test system. 862.1225 Section 862.1225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  6. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Creatinine test system. 862.1225 Section 862.1225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  7. 21 CFR 862.1225 - Creatinine test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Creatinine test system. 862.1225 Section 862.1225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  8. Low temperature Raman and DFT study of creatinine

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

  9. Blood pressure and serum creatinine in obese female.

    PubMed

    Asrin, M; Nessa, A; Hasan, M I; Das, R K

    2015-01-01

    Obesity is increasing in developed as well as in developing countries. This analytical cross sectional study was carried out to document the relation between blood pressure, serum creatinine and body mass index in female and to assess potential health differences among obese female and normal weight female. This study was done in the Department of Physiology, Mymensingh Medical College, Mymensingh, Bangladesh from July 2012 to June 2013. Seventy female persons volunteered as subjects. Among them 35 were within normal weight (BMI 18.5-24.9kg/m˛) and 35 were obese (BMI?30kg/m˛). Non probability purposive type of sampling technique was used to select the subjects. Measurement of body mass index and blood pressure were done as per procedure. Serum creatinine level was estimated by enzymatic colorimetric method. The results were calculated and analyzed by using SPSS (statistical package for social science, version 17.0), scientific electronic calculator and simultaneously with a computer assisted program like Microsoft excel. Unpaired 't' test was applied to find the significance of difference regarding serum creatinine and blood pressure levels in obese female. The value of p was 1% to indicate highly significant and 5% to indicate simply significant or statistically significant. The mean±SE of systolic blood pressure, diastolic blood pressure and serum creatinine levels were 135.71±1.58mmHg, 88.74±0.95mmHg and 1.03±0.01mg/dl respectively; significant at 1% level for obese group of BMI (p<0.0001). The examinations and biochemical investigations revealed that high BMI is significantly related to increased levels of serum creatinine & blood pressure in obese female which indicate the obese subjects are prone to cardiovascular & metabolic risk. PMID:25725665

  10. Liver Enzymes and Uric acid in Acute Heart Failure

    PubMed Central

    Vakilian, Farveh; Rafighdoost, Abbas Ali; Rafighdoost, Amir Hossein; Amin, Ahmad; Salehi, Maryam

    2015-01-01

    Background: Acute heart failure (AHF) is defined as the new onset or recurrence of gradual or rapidly worsening signs and symptoms of heart failure, requiring urgent or emergent therapy. Objectives: This study attempts to assess the association of liver function tests (LFT) and uric acid level with in hospital outcome and echocardiography parameters, in patients with acute decompensated heart failure. Patients and Methods: A total of 100 patients (aged 16 - 90 years, 60% men) admitted with AHF were enrolled. LFTs and uric acid levels were assessed on first day and before discharge, and patients were followed for 3 months. Results: In-hospital outcomes were considered. Mean Left Ventricular Ejection Fraction (LVEF) was 35% (20 - 45%). Mean Uric acid level was 8.4 mg/dL, significantly higher than chronic HF and normal groups (P < 0.02). Elevated liver enzymes were seen in 52% patients, mostly (87%) in transaminases. Liver enzymes were decreased in 85% patients before discharge. LFT and uric acid levels were inversely and significantly correlated with LVEF on echocardiography (P = 0.02), but not with diastolic parameters. Although there was no significant correlation between uric acid level and in-hospital mortality, risk of intubation and rehospitalization in 3 months, enzyme levels increased in these groups. Increased aspartate transaminase (AST level) was associated with inotrope infusion in AHF patients (42 vs. 82 mg/dL, P = 0.03). Conclusions: Abnormal transaminases and uric acid levels are seen in AHF patients. Increased AST levels may be a predictor of the need for inotrope during hospital course in these patients. PMID:26528447

  11. Blood urea nitrogen to creatinine ratio is associated with congestion and mortality in heart failure patients with renal dysfunction.

    PubMed

    Parrinello, Gaspare; Torres, Daniele; Testani, Jeffrey M; Almasio, Piero Luigi; Bellanca, Michele; Pizzo, Giuseppina; Cuttitta, Francesco; Pinto, Antonio; Butler, Javed; Paterna, Salvatore

    2015-12-01

    Renal dysfunction (RD) and venous congestion are related and common in heart failure (HF). Studies suggest that venous congestion may be the primary driver of RD in HF. In this study, we sought to investigate retrospectively the relationship between common measures of renal function with caval congestion and mortality among outpatients with HF and RD. We reviewed data from 103 HF outpatients (45 males, mean age 74 years, ejection fraction 41.8 ± 11.6 %) with estimated glomerular filtration rate (eGFR) of <60 ml/min in a single centre. During an ambulatory visit, all patients underwent blood test and ultrasonography of the inferior vena cava (IVC). Caval congestion was defined as IVC with both dilatation and impaired collapsibility. The best values of renal metrics in predicting caval congestion were determined with receiver-operating characteristic analysis. The BUN/Cr ratio is moderately correlated with IVC expiratory maximum diameter (r = 0.31, p < 0.0007). In a multiple logistic regression model, BUN/Cr >25.5 (adjusted OR 2.98, p 0.015) and eGFR ?45.8 (adjusted OR 5.38, p 0.002) identify patients at risk for caval congestion; a BUN/Cr >23.7 was the best predictor of impaired collapsibility (adjusted OR 4.41, p 0.001). a BUN/Cr >25.5 (HR 2.19, 95 % CI 1.21-3.94, p < 0.001) and NYHA class 3 (HR 2.91, 95 % CI 1.60-5.31, p < 0.0005) were independent risk factors associated with all-cause death during a median follow-up of 31 months. In outpatients with HF and RD, a higher BUN/Cr and lower eGFR are reliable renal biomarkers for caval congestion. The BUN/Cr is associated with long-term mortality and may help to stratify HF severity. PMID:26037394

  12. New enzymatic assay for serum urea nitrogen using urea amidolyase.

    PubMed

    Kimura, Shigeki; Iyama, Shigeru; Yamaguchi, Yoshihisa; Kanakura, Yuzuru

    2003-01-01

    We established an enzymatic assay for measurement of serum urea nitrogen using urea amidolyase (EC 3.5.1.45) from yeast species. The method is based on hydrolysis of urea by the enzyme. In this assay, we eliminated endogenous ammonium ion by use of glutamate dehydrogenase (EC 1.4.1.4). Then in the presence of urea amido-lyase, ATP, bicarbonate, magnesium, and potassium ions, ammonium ion was produced proportionally to urea concentration in serum. The concentra-tion of ammonium ion formed was determined by adding GLDH to produce NADP(+) in the presence of 2-oxoglutarate and NADPH. We then monitored the change of absorbance at 340 nm. The inhibitory effect of calcium ion on this assay was eliminated by adding glyco-letherdiamine-N, N, N', N'-tetraacetic acid to the reaction system. The with-in-assay coefficient of variations (CVs) of the present method were 1.80-3.76% (n = 10) at 2.8-19.0 mmol/L, respectively. The day-to-day CVs were 2.23-4.59%. Analytical recovery was 92-115%. The presence of ascorbic acid, bilirubin, hemoglobin, lipemic material, ammo-nium ion, or calcium ion did not affect this assay system. The correlation be-tween values obtained with the present method (y) and those by another enzy-matic method (x) was 0.997 (y = 1.02x - 0.10 mmol/L, Sy/x = 0.841, n = 100), with a mean difference of -0.18 +/- 0.86 mmol/L [(values by reference method - that of present method) +/- SD] using the Bland-Altman technique. J. Clin. Lab. Anal. 17:52-56, 2003. PMID:12640627

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

    PubMed Central

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

    2014-01-01

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

  14. Kocher-Debré-Semelaigne syndrome with rhabdomyolysis and increased creatinine.

    PubMed

    Cimbek, Emine Ayça; ?en, Ya?ar; Yuca, Sevil Ar?; Çam, Demet; Gür, Celal; Peru, Harun

    2015-11-01

    Association of Kocher-Debré-Semelaigne syndrome-a myopathy of hypothyroidism in childhood characterized by muscular hypertrophy, with rhabdomyolysis is very rare. We present a case of Kocher-Debré-Semelaigne syndrome with rhabdomyolysis secondary to Hashimoto's thyroiditis. He had muscular symptoms simulating poly/dermatomyositis, massively elevated creatine kinase (CK) levels and high creatinine levels. All of the findings reversed on treatment of hypothyroidism. The response to the therapy strongly suggested that Kocher-Debré-Semelaigne (KDS) syndrome was the underlying etiology. Serum thyroid- stimulating hormone levels should be routinely determined in all patients with muscular symptoms and/or elevation of CK and creatinine, keeping KDS syndrome in mind. PMID:26181046

  15. What Is a Urea Cycle Disorder?

    MedlinePLUS

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

  16. Remote calorimetric detection of urea via flow injection analysis.

    PubMed

    Gaddes, David E; Demirel, Melik C; Reeves, W Brian; Tadigadapa, Srinivas

    2015-12-01

    The design and development of a calorimetric biosensing system enabling relatively high throughput sample analysis are reported. The calorimetric biosensor system consists of a thin (?20 ?m) micromachined Y-cut quartz crystal resonator (QCR) as a temperature sensor placed in close proximity to a fluidic chamber packed with an immobilized enzyme. Layer by layer enzyme immobilization of urease is demonstrated and its activity as a function of the number of layers, pH, and time has been evaluated. This configuration enables a sensing system where a transducer element is physically separated from the analyte solution of interest and is thereby free from fouling effects typically associated with biochemical reactions occuring on the sensor surface. The performance of this biosensing system is demonstrated by detection of 1-200 mM urea in phosphate buffer via a flow injection analysis (FIA) technique. Miniaturized fluidic systems were used to provide continuous flow through a reaction column. Under this configuration the biosensor has an ultimate resolution of less than 1 mM urea and showed a linear response between 0-50 mM. This work demonstrates a sensing modality in which the sensor itself is not fouled or contaminated by the solution of interest and the enzyme immobilized Kapton® fluidic reaction column can be used as a disposable cartridge. Such a system enables reuse and reliability for long term sampling measurements. Based on this concept a biosensing system is envisioned which can perform rapid measurements to detect biomarkers such as glucose, creatinine, cholesterol, urea and lactate in urine and blood continuously over extended periods of time. PMID:26479269

  17. Creatinine kinetics and the definition of acute kidney injury.

    PubMed

    Waikar, Sushrut S; Bonventre, Joseph V

    2009-03-01

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

  18. 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…

  19. Urea Biosynthesis Using Liver Slices

    ERIC Educational Resources Information Center

    Teal, A. R.

    1976-01-01

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

  20. 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 ...

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

    E-print Network

    Hammock, Bruce D.

    Creatinine Measurements in 24 h Urine by Liquid Chromatography-Tandem Mass Spectrometry EUN (LC-MS/MS) method for determining urinary creatinine was developed and used to evaluate 24 h urine of creatinine was 0.59 min. The linear range was 1-2000 ng/mL, with a detection limit in urine of 1 ng/mL. LC

  2. Urea-triazone N characteristics and uses.

    PubMed

    Clapp, J G

    2001-11-21

    Urea-triazone nitrogen (N) is a stable solution resulting from a controlled reaction in aqueous medium of urea, formaldehyde, and ammonia which contains at least 25% total N. This N source contains no more than 40%, nor less than 5%, of total N from unreacted urea and not less that 40% from triazone. All other N shall be derived from water-soluble dissolved reaction products of the above reactants. It is a source of slowly available N. The rate of mineralization of urea-triazone is about 66% that of urea after 8 days when incorporated in a Munjor sandy loam. Ammonia volatilization losses of N applied as urea-triazone were about 41% of those from urea on a Cecil sandy loam in the first week after application. N leaching losses through saturated Yolo loam columns of urea-triazone were about two thirds that of urea or nitrate N. This N source has proven to be a safer and more effective material for direct application on plant foliage. Tomato growth was enhanced with foliar application of urea-triazone relative to that obtained from ammonium nitrate or urea. The stability of this N source from potential losses via ammonia volatilization and nitrate leaching when soil applied is also documented by results from university trials. PMID:12805784

  3. 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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Sittiwong, Jarinya; Unob, Fuangfa

    2015-03-01

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

  6. The effect of uric acid on outdoor copper and bronze.

    PubMed

    Bernardi, E; Bowden, D J; Brimblecombe, P; Kenneally, H; Morselli, L

    2009-03-15

    Bird droppings are often quoted as a decay agent for outdoor goods, in particular buildings and statues. Undoubtedly, they represent one of the major causes of aesthetic damage on outdoor materials, but the real chemical damage they are able to induce, in particular on metals, is not so well studied. This work focused on the short term role of uric acid, the main constituent of bird urine, with respect to copper, which make such an important contribution to architectural elements of buildings and outdoor sculpture. Preliminary results of laboratory tests and analyses on real exposed samples showed that uric acid chemically affects copper and bronzes: the surface of the metal is modified and copper urates formed. Also natural patina, formed on statues and roof, react with uric acid, even if it seems to afford some protection toward bird droppings. In general, experimental results confirm that the potential chemical damage by bird droppings is significant when considering external cultural heritage such as statues, metal monuments and buildings with historic copper roofs. PMID:19157513

  7. 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.

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

    PubMed

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

    2013-10-01

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

  9. Impacts of active urea secretion into pars recta on urine concentration and urea excretion rate

    PubMed Central

    Layton, Anita T; Bankir, Lise

    2013-01-01

    It has been observed experimentally that early distal tubular urea flow exceeds urea delivery by the proximal convoluted tubule to the pars recta and loop of Henle. Moreover, the fractional excretion of urea in the urine may exceed values compatible with the reabsorption known to occur in the proximal convoluted tubule in the cortex. A likely explanation for these observations is that urea may be actively secreted into the pars recta, as proposed in a few studies. However, this hypothesis has yet to be demonstrated experimentally. In this study, we used a mathematical model of the renal medulla of the rat kidney to investigate the impacts of active urea secretion in the intrarenal handling of urea and in the urine concentrating ability. The model represents only the outer and inner medullary zones, with the actions taking place in the cortex incorporated via boundary conditions. Blood flow in the model vasculature is divided into plasma and red blood cell compartments. We compared urea flow rates and other related model variables without and with the hypothetical active urea secretion in the pars recta. The simulation suggests that active urea secretion induces a “urea-selective” improvement in urine concentrating ability by enhancing the efficiency of urea excretion without requiring a higher urine flow rate, and with only modest changes in the excretion of other solutes. These results should encourage experimental studies in order to assess the existence of an active urea secretion in the rodent kidney. PMID:24058732

  10. Assessment of microalbuminuria and albumin creatinine ratio in patients with type 2 diabetes mellitus

    PubMed Central

    Karar, Tarig; Alniwaider, Rashed Ahmed R.; Fattah, Mohamed Abdel; Al Tamimi, Waleed; Alanazi, Abdullah; Qureshi, Shoeb

    2015-01-01

    Aim: We aimed to evaluate the levels of urine microalbumin, urine albumin creatinine ratio, plasma creatinine and glycosylated hemoglobin (HbA1c) among type 2 diabetic patients and assessed the correlation between microalbuminuria and plasma creatinine levels. Materials and Methods: A retrospective chart review study was conducted at Department of Clinical Chemistry, King Abdulaziz Medical City in Riyadh, Saudi Arabia, during August to December 2014. The study included 100 male and female patients diagnosed with type 2 diabetes mellitus (DM) and excluding patients with type 1 DM. Medical history and biochemical laboratory data were obtained from medical records and from biochemistry laboratory database. Results: Increase in mean level of plasma creatinine (138 ?mol/L), urine microalbuminuria (240 mg/L), albumin creatinine ratio (82) and HbA1c (8.7%) was observed among type 2 DM patients. Moderate positive correlation was observed between microalbuminuria and urine albumin creatinine ratio (r = 0.509 P = 0.0006) and between urine albumin creatinine ratio and plasma creatinine (r = 0.553 P = 0.017). Conclusion: We concluded that type 2 DM patients who are at risk of developing renal impairment must be regularly monitored for microalbuminuria, urine albumin creatinine ratio, and HbA1c levels. PMID:26604628

  11. 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...

  12. 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...

  13. Extraction of urea and ammonium ion

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  14. 21 CFR 184.1923 - Urea.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Urea. 184.1923 Section 184.1923 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1923 Urea....

  15. 21 CFR 184.1923 - Urea.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea. 184.1923 Section 184.1923 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1923 Urea....

  16. Hydrogel allergic contact dermatitis and imidazolidinyl urea/diazolidinyl urea.

    PubMed

    Carvalho, Rodrigo; Maio, Paula; Amaro, Cristina; Santos, Raquel; Cardoso, Jorge

    2011-12-01

    Hydrogels contain modified carboxymethylcellulose polymer together with propylene glycol as known components. Nowadays, they are common agents used in the treatment of leg ulcer patients, and a possible cause of allergic contact dermatitis. However in the published data, not all the patients with positive patch tests to hydrogels were sensitized to propylene glycol, remaining some allergens to be identified. The authors describe two leg ulcer patients sensitized for different commercial available hydrogels tested "as is", with concomitant patch tested positivity to imidazolidinyl urea (IU) and diazolidinyl urea (DU). Patient A was an 84-year-old male, and patient B was a 77-year-old female, both with a known history of leg ulcer for more than 8 weeks. Patient A was sensitized for Intrasite Gel(®), Hydrogel Nu-Gel(®), Askina Gel(®), neomycin and budesonide. Patient B was sensitized for Intrasite Gel(®), Hydrogel Nu-Gel(®), Askina Gel(®), Hydrosorb Gel(®), Fragance mix 1 and 2, Amerchol, geraniol and citral. They were negative to propylene glycol tested in 5% pet. and 20% aq. IU and DU are formaldehyde-releasing agents, used as antimicrobial preservatives in the formulation of pharmaceutical creams and ointments and are known to cause contact dermatitis. Also, in many studies performed, it has been shown that contact allergy is high in patients with leg ulcers. As result, assessment of the relevance of positive patch test reactions in these patients can be difficult. Although we were not able to get the complete ingredient list of the hydrogels tested, attending to these observations, could be of importance to evaluate the presence of IU/DU in patients with suspected contact dermatitis to hydrogels. PMID:21425953

  17. 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.

  18. Transport characteristics of urea transporter-B.

    PubMed

    Yang, Baoxue

    2014-01-01

    UT-B represents the major urea transporter in erythrocytes, in addition to being expressed in kidney descending vasa recta, brain, spleen, ureter, bladder, and testis. Expression of urea transporter UT-B confers high urea permeability to mammalian erythrocytes. Erythrocyte membranes are also permeable to various urea analogues, suggesting common transport pathways for urea and structurally similar solutes. UT-B is highly permeable to urea and the chemical analogues formamide, acetamide, methylurea, methylformamide, ammonium carbamate, and acrylamide, each with a Ps > 5.0 × 10(-6) cm/s at 10 °C. The amides formamide, acetamide, acrylamide, and butyramide efficiently diffuse across lipid bilayers. The urea analogues dimethylurea, acryalmide, methylurea, thiourea, and methylformamide inhibit UT-B-mediated urea transport by >60 % by a pore-blocking mechanism. UT-B is also a water channel in erythrocytes and has a single-channel water permeability that is similar to aquaporin-1. Whether UT-B is an NH3 channel still needs further study. Urea permeability (Purea) in erythrocytes differs between different mammals. Carnivores (dog, fox, cat) exhibit high Purea. In contrast, herbivores (cow, donkey, sheep) show much lower Purea. Erythrocyte Purea in human and pig (omnivores) was intermediate. Rodents and lagomorphs (mouse, rat, rabbit) have Purea intermediate between carnivores and omnivores. Birds that do not excrete urea and do not express UT-B in their erythrocytes have very low values. In contrast to Purea, water permeability is relatively similar in all mammals studied. This chapter will provide information about the transporter characteristics of UT-B. PMID:25298342

  19. Some reactions of the ureas

    E-print Network

    Geauque, Harry Aiman

    1915-01-01

    was reorystallised from hot alcohol and melted at 80S0. This was 2-Thiocarb- onyl-,5-Dike to-1,3,-Diphenyltetrahydroimidazol#. The reaction was HC1 C6H5ITH C1C0 C6H5?"~—9° +H01. Si C6H5UH CICO 06H5!f— 00 M. V. Stojentin+ prepared this compound by heating... was recrystallised several times from- (CH3)2C6H3NC8 + H2S M01T0PHKNYL THIOUREA and DIPHENYL UREA CHLORIDE 5. alcohol and finally from gasoline which gave a crystalline comp­ ound. This melted at 190° "but there was very little of it, and not enough to identify...

  20. Wearable salivary uric acid mouthguard biosensor with integrated wireless electronics.

    PubMed

    Kim, Jayoung; Imani, Somayeh; de Araujo, William R; Warchall, Julian; Valdés-Ramírez, Gabriela; Paixăo, Thiago R L C; Mercier, Patrick P; Wang, Joseph

    2015-12-15

    This article demonstrates an instrumented mouthguard capable of non-invasively monitoring salivary uric acid (SUA) levels. The enzyme (uricase)-modified screen printed electrode system has been integrated onto a mouthguard platform along with anatomically-miniaturized instrumentation electronics featuring a potentiostat, microcontroller, and a Bluetooth Low Energy (BLE) transceiver. Unlike RFID-based biosensing systems, which require large proximal power sources, the developed platform enables real-time wireless transmission of the sensed information to standard smartphones, laptops, and other consumer electronics for on-demand processing, diagnostics, or storage. The mouthguard biosensor system offers high sensitivity, selectivity, and stability towards uric acid detection in human saliva, covering the concentration ranges for both healthy people and hyperuricemia patients. The new wireless mouthguard biosensor system is able to monitor SUA level in real-time and continuous fashion, and can be readily expanded to an array of sensors for different analytes to enable an attractive wearable monitoring system for diverse health and fitness applications. PMID:26276541

  1. High plasma uric acid concentration: causes and consequences

    PubMed Central

    2012-01-01

    High plasma uric acid (UA) is a precipitating factor for gout and renal calculi as well as a strong risk factor for Metabolic Syndrome and cardiovascular disease. The main causes for higher plasma UA are either lower excretion, higher synthesis or both. Higher waist circumference and the BMI are associated with higher insulin resistance and leptin production, and both reduce uric acid excretion. The synthesis of fatty acids (tryglicerides) in the liver is associated with the de novo synthesis of purine, accelerating UA production. The role played by diet on hyperuricemia has not yet been fully clarified, but high intake of fructose-rich industrialized food and high alcohol intake (particularly beer) seem to influence uricemia. It is not known whether UA would be a causal factor or an antioxidant protective response. Most authors do not consider the UA as a risk factor, but presenting antioxidant function. UA contributes to > 50% of the antioxidant capacity of the blood. There is still no consensus if UA is a protective or a risk factor, however, it seems that acute elevation is a protective factor, whereas chronic elevation a risk for disease. PMID:22475652

  2. 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.

  3. Quantitative concentration measurements of creatinine dissolved in water and urine using Raman

    E-print Network

    Berger, Andrew J.

    Quantitative concentration measurements of creatinine dissolved in water and urine using Raman (LCOF) geometry to enhance the collection of Raman scattering from the biochemical creatinine, dissolved in water and in urine. At short integration times, where shot noise is most troublesome, the enhanced

  4. How we estimate GFR--a pitfall of using a serum creatinine-based formula.

    PubMed

    Refaie, R; Moochhala, S H; Kanagasundaram, N S

    2007-10-01

    Chronic kidney disease (CKD) is defined using the estimated glomerular filtration rate (eGFR). This has led to a large increase in the diagnosis of CKD in the United Kingdom, the majority of which is in its earlier stages and is detected in non-hospital settings. It is important to be aware that eGFR calculations will reflect inaccuracies in the measured serum creatinine, as the latter is an important component of the calculation. We report a case in which a patient with high muscle-mass who had consumed large quantities of a creatine-containing nutritional supplement presented with apparently reduced renal function on the basis of the serum creatinine and therefore also the eGFR calculation (MDRD equation). Creatine is an amino acid which is a precursor of creatinine, and is known to transiently increase serum creatinine. 6 weeks after discontinuing creatine ingestion, serum creatinine had fallen but still gave rise to an apparently abnormal calculated eGFR. In fact, renal function was shown to be normal when estimated using 24-hour urinary creatinine clearance. This case demonstrates that the upper extreme of muscle mass and ingestion of creatine can affect not only serum creatinine but also the calculated eGFR. Knowledge of common confounding factors and their effects on serum creatinine and eGFR will allow appreciation of the limitations of these measures of renal function, and can prevent unnecessary over-investigation of such patients. PMID:17969491

  5. Computer prediction of the need for dialysis and transplantation using calculated creatinine clearance.

    PubMed Central

    Ballardie, F W; Gartside, S; Mallick, N P

    1983-01-01

    A computerised system capable of prospective assessment of the course of chronic renal failure has been devised. Rapid analysis is possible of the progress of a large cohort of patients and therefore of the prospective load on renal unit facilities. Calculated creatinine clearance values provide a more accurate and earlier prediction of end stage failure than the reciprocals of serum creatinine values. PMID:6404450

  6. Decreased serum creatinine concentration is associated with short telomeres of adipose tissue cells.

    PubMed

    Fernández-Real, J M; Moreno-Navarrete, J M; Ortega, F; Ricart, W

    2011-07-01

    Decreased serum creatinine concentration has been recently described to constitute a new risk factor of type 2 diabetes. Increased free radicals have been consistently associated with decreased serum creatinine and with cellular senescence. Telomere length is considered as a biological marker for senescence. We aimed to study the association of telomere length with serum creatinine. Telomere length of subcutaneous adipose tissue cells was measured in a sample of obese and nonobese subjects (n = 49). Telomere length of subcutaneous adipose tissue cells was positively associated with serum creatinine (r = 0.40, P = 0.004), i.e., the lower the telomere length, the lower the serum creatinine, but not with glomerular filtration rate (GFR). In addition, telomere length was negatively associated with BMI (r = -0.45, P = 0.001) and systolic blood pressure (r = -0.41, P = 0.003). In a multiple linear regression analysis, BMI (P = 0.005), systolic blood pressure (P = 0.01) and telomere length (P = 0.03) independently contributed to 37% of serum creatinine variance after controlling for sex and age. In conclusion, the association of serum creatinine with a marker of cellular senescence suggests an underlying mechanism influencing both decreased serum creatinine and increased risk of type 2 diabetes. PMID:21350437

  7. The significance of post-operative creatinine in predicting prognosis in cardiac surgery patients.

    PubMed

    Ye, Ming; Dai, Qingqing; Zheng, Junbo; Jiang, Xuesong; Wang, Huaiquan; Lou, Shaofei; Yu, Kaijiang

    2014-09-01

    The purpose of the study is to investigate the effectiveness of serum creatinine, the most common indicator of acute kidney injury (AKI), in predicting the prognosis of critically ill patients after cardiac surgery. Also, we sought to validate the use of this biomarker in assessing the direct outcome of a clinical setting. We selected 592 patients from our hospital; the relevant information including name, disease, gender, age, EuroSCORE, length of stay (LOS), days of mechanical ventilation, days of noninvasive positive pressure ventilation, days of continuous renal replacement treatment, and mortality was recorded. Creatinine of pre-operative, 24, and 48 h post-operation specimens were analyzed. The difference in serum creatinine levels at various time points was compared using t test. Spearman correlation was used to analyze the correlation of serum creatinine to AKI and hard outcomes. Receiver-operating characteristic curves were generated, and the areas under the curves (AUCs) were compared to validate the adequacy of creatinine in predicting the post-operative AKI. The 48 h post-operative and pre-operative serum creatinine were found to be informative in predicting the outcome of patients as indicated by the t test and Spearman correlation analysis. The 48 h creatinine with AUC of 0.811 was indicated to be significantly associated with the hard outcome. However, the 24 h and pre-operative creatinine with AUCs of 0.701 and 0.658, respectively, were not adequately related to the outcomes. In conclusion, contrary to the existing belief that creatinine is not an informative parameter for the diagnosis and prognosis of AKI, we found that when measured at 48 h of cardiac surgery, serum creatinine is reflective of the outcome. PMID:24782058

  8. Urea and water permeability in dogfish (Squalus acanthias) gills.

    PubMed

    Pärt, P; Wright, P A; Wood, C M

    1998-01-01

    We used a perfused gill preparation from dogfish to investigate the origin of low branchial permeability to urea. Urea permeability (14C-urea) was measured simultaneously with diffusional water permeability (3H2O). Permeability coefficients for urea and ammonia in the perfused preparation were almost identical to in vivo values. The permeability coefficient of urea was 0.032 x 10(-6) cm/sec and of 3H2O 6.55 x 10(-6) cm/sec. Adrenalin (1 x 10(-6) M) increased water and ammonia effluxes by a factor of 1.5 and urea efflux by a factor of 3.1. Urea efflux was almost independent of the urea concentration in the perfusion medium. The urea analogue thiourea in the perfusate had no effect on urea efflux, whereas the non-competitive inhibitor of urea transport, phloretin, increased efflux markedly. The basolateral membrane is approximately 14 times more permeable to urea than the apical membrane. We conclude that the dogfish apical membrane is extremely tight to urea, but the low apparent branchial permeability may also relate to the presence of an active urea transporter on the basolateral membrane that returns urea to the blood and hence reduces the apical urea gradient. PMID:11253775

  9. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and...

  10. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and...

  11. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and...

  12. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and...

  13. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and...

  14. Urea and deuterium mixtures at high pressures.

    PubMed

    Donnelly, M; Bull, C L; Husband, R J; Frantzana, A D; Klotz, S; Loveday, J S

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D2 mixtures that indicate no inclusion compound forms up to 3.7 GPa. PMID:25833592

  15. Surface modified silicon nanochannel for urea sensing

    E-print Network

    Chen, Yu; Hong, Mi; Erramilli, Shyamsunder; Mohanty, Pritiraj

    2008-01-01

    Silicon nanowires have been surface functionalized with the enzyme urease for biosensor applications to detect and quantify urea concentration. The device is nanofabricated from a silicon on insulator (SOI) wafer with a top down lithography approach. The differential conductance of silicon nanowires can be tuned for optimum performance using the source drain bias voltage, and is sensitive to urea at low concentration. The experimental results show a linear relationship between surface potential change and urea concentration in the range of 0.1 to 0.68 mM. The sensitivity of our devices shows high reproducibility with time and different measurement conditions. The nanowire urea biosensor offers the possibility of high quality, reusable enzyme sensor array integration with silicon based circuits.

  16. Urea and deuterium mixtures at high pressures

    SciTech Connect

    Donnelly, M. Husband, R. J.; Frantzana, A. D.; Loveday, J. S.; Bull, C. L.; Klotz, S.

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  17. 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.

  18. 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

  19. Uric Acid Levels Can Predict Metabolic Syndrome and Hypertension in Adolescents: A 10-Year Longitudinal Study

    PubMed Central

    Sun, Hai-Lun; Pei, Dee; Lue, Ko-Huang; Chen, Yen-Lin

    2015-01-01

    The relationships between uric acid and chronic disease risk factors such as metabolic syndrome, type 2 diabetes mellitus, and hypertension have been studied in adults. However, whether these relationships exist in adolescents is unknown. We randomly selected 8,005 subjects who were between 10 to 15 years old at baseline. Measurements of uric acid were used to predict the future occurrence of metabolic syndrome, hypertension, and type 2 diabetes. In total, 5,748 adolescents were enrolled and followed for a median of 7.2 years. Using cutoff points of uric acid for males and females (7.3 and 6.2 mg/dl, respectively), a high level of uric acid was either the second or third best predictor for hypertension in both genders (hazard ratio: 2.920 for males, 5.222 for females; p<0.05). However, uric acid levels failed to predict type 2 diabetes mellitus, and only predicted metabolic syndrome in males (hazard ratio: 1.658; p<0.05). The same results were found in multivariate adjusted analysis. In conclusion, a high level of uric acid indicated a higher likelihood of developing hypertension in both genders and metabolic syndrome in males after 10 years of follow-up. However, uric acid levels did not affect the occurrence of type 2 diabetes in both genders. PMID:26618358

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

    PubMed

    Numnuam, Apon; Thavarungkul, Panote; Kanatharana, Proespichaya

    2014-06-01

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

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

    PubMed Central

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

    2012-01-01

    A simple and sensitive high performance liquid chromatography-tandem mass spectrometry (HPLC-ESI-MS-MS) method was developed and validated for the quantification of creatinine in human urine. The analysis was carried out on an Agilent Zorbax Eclipse XDB-C18 column (2.1 × 150?mm, 3.5??m). The mobile phase was 0.1% formic acid in water and 0.1% formic acid in acetonitrile (50/50, v/v). Linear calibration curves were obtained in the concentration range of 1–2000.0?ng/mL, with a lower limit of quantification of 0.99?ng/mL. The intra- and interday precision (RSD) values were below 3%. The method was successfully applied to a bioequivalence study of creatinine in Chinese smokers and nonsmokers. The total cotinine in 24?h urine and cotinine?:?creatinine ratio were also positively associated (Pearson R = 0.942, P < 0.0001). However, cotinine?:?creatinine ratio varied significantly across smoking groups for the difference of individual. 24?h urinary cotinine was more appropriate for expressing correlation with tar than cotinine?:?creatinine ratio. PMID:23209947

  2. Xenobiotic-urea conjugates; chemical or biological?

    PubMed

    Mitchell, Stephen C

    2014-12-01

    1. Although the major pathways involved in drug metabolism have been elucidated, there remain those routes that may be considered as minor, esoteric, or even artifactual. 2. Conjugation with urea, an abundant, non-toxic, small water soluble molecule, is such a disputed and debatable Phase II pathway. 3. The present article collates data gleaned from the literature concerning xenobiotic-urea conjugation, presents pertinent information resurrecting the controversy and poses questions as to the nature of the phenomenon. PMID:25144804

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2006-03-01

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

  5. A Mendelian Randomization Study of Circulating Uric Acid and Type 2 Diabetes.

    PubMed

    Sluijs, Ivonne; Holmes, Michael V; van der Schouw, Yvonne T; Beulens, Joline W J; Asselbergs, Folkert W; Huerta, José María; Palmer, Tom M; Arriola, Larraitz; Balkau, Beverley; Barricarte, Aurelio; Boeing, Heiner; Clavel-Chapelon, Françoise; Fagherazzi, Guy; Franks, Paul W; Gavrila, Diana; Kaaks, Rudolf; Khaw, Kay Tee; Kühn, Tilman; Molina-Montes, Esther; Mortensen, Lotte Maxild; Nilsson, Peter M; Overvad, Kim; Palli, Domenico; Panico, Salvatore; Quirós, J Ramón; Rolandsson, Olov; Sacerdote, Carlotta; Sala, Núria; Schmidt, Julie A; Scott, Robert A; Sieri, Sabina; Slimani, Nadia; Spijkerman, Annemieke M W; Tjonneland, Anne; Travis, Ruth C; Tumino, Rosario; van der A, Daphne L; Sharp, Stephen J; Forouhi, Nita G; Langenberg, Claudia; Riboli, Elio; Wareham, Nicholas J

    2015-08-01

    We aimed to investigate the causal effect of circulating uric acid concentrations on type 2 diabetes risk. A Mendelian randomization study was performed using a genetic score with 24 uric acid-associated loci. We used data of the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct case-cohort study, comprising 24,265 individuals of European ancestry from eight European countries. During a mean (SD) follow-up of 10 (4) years, 10,576 verified incident case subjects with type 2 diabetes were ascertained. Higher uric acid was associated with a higher diabetes risk after adjustment for confounders, with a hazard ratio (HR) of 1.20 (95% CI 1.11, 1.30) per 59.48 µmol/L (1 mg/dL) uric acid. The genetic score raised uric acid by 17 µmol/L (95% CI 15, 18) per SD increase and explained 4% of uric acid variation. By using the genetic score to estimate the unconfounded effect, we found that a 59.48 µmol/L higher uric acid concentration did not have a causal effect on diabetes (HR 1.01 [95% CI 0.87, 1.16]). Including data from the Diabetes Genetics Replication And Meta-analysis (DIAGRAM) consortium, increasing our dataset to 41,508 case subjects with diabetes, the summary odds ratio estimate was 0.99 (95% CI 0.92, 1.06). In conclusion, our study does not support a causal effect of circulating uric acid on diabetes risk. Uric acid-lowering therapies may therefore not be beneficial in reducing diabetes risk. PMID:25918230

  6. 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

  7. Effect of slow-release urea inclusion in diets containing modified corn distillers grains on total tract digestibility and ruminal fermentation in feedlot cattle.

    PubMed

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

    2015-08-01

    Ruminal degradable intake protein (DIP) deficit may result when cattle are fed diets containing a greater inclusion of processed corn grain and small to moderate inclusion of corn distillers grains (DG). This deficit may arise from greater proportions of rapidly fermentable carbohydrates and RUP in corn grain. Urea-derived N is 100% DIP; however, rates of degradation of carbohydrates and conventional urea (CU) may not match. Therefore, beneficial effects may result from the use of slow-release urea (SRU) sources over CU when added to DIP-deficient diets. An experiment was conducted to evaluate the effect of increasing DIP concentration through inclusion of 1 of 2 SRU sources or CU in DG-containing feedlot diets on ruminal fermentation and total tract digestibility. In addition, an in situ experiment was conducted to characterize N disappearance of urea sources from polyester bags. Four ruminally cannulated steers (initial BW = 588 ± 8 kg) were arranged in a 4 × 4 Latin square design and assigned randomly to 1 of 4 dietary treatments containing 0% (CON) or 0.6% urea in the form of CU (UREA) or SRU as Optigen II (polymer-encapsulated urea; OPTI) or NitroShure (lipid-encapsulated urea; NITRO), and 30% corn earlage, 20% modified corn DG with solubles, 7.8% corn silage, 4.3% dry supplement, and dry-rolled corn (DM basis). Dietary DIP was estimated at 6.6% and 8.3% for CON and urea-containing dietary treatments, respectively. Steers were fed ad libitum once daily. Differences in purine derivatives-to-creatinine (PDC) index between treatments were used as indicators of differences in microbial CP synthesis. Intake of OM, digestibility of OM, NDF, CP, and starch, ruminal pH, total VFA ruminal concentration, and PDC index were not affected by treatment ( ? 0.21). Concentration of ammonia-N noticeably peaked at 4 h after feed delivery for cattle fed UREA (treatment × time, = 0.06) and measured at least 5.5 mg/dL for any treatment and at any hour after feed delivery. During the first 12 h after incubation, N disappearance was greater for CU and NitroShure than Optigen II (urea source × time, < 0.01). Supplementing DIP through inclusion of CU or SRU did not affect feed intake, digestibility, or most of the ruminal fermentation parameters evaluated, which may relate to the lack of need of urea supplementation in the present experiment. More research is warranted to evaluate the use of SRU in DIP-deficient diets. PMID:26440185

  8. 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

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

    SciTech Connect

    Weaver, Virginia M.; Kim, Nam-Soo; Lee, Byung-Kook; Parsons, Patrick J.; Department of Environmental Health Sciences, School of Public Health, University at Albany, Albany, NY ; Spector, June; Fadrowski, Jeffrey; Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD ; Jaar, Bernard G.; Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD; Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD ; Steuerwald, Amy J.; Department of Environmental Health Sciences, School of Public Health, University at Albany, Albany, NY ; Todd, Andrew C.; and others

    2011-11-15

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

  10. Creatinine Change on Vasoconstrictors as Mortality Surrogate in Hepatorenal Syndrome: Systematic Review & Meta-Analysis

    PubMed Central

    Belcher, Justin M.; Coca, Steven G.; Parikh, Chirag R.

    2015-01-01

    Background and Aims Hepatorenal syndrome is a severe complication of cirrhosis and associates with significant mortality. Vasoconstrictor medications improve renal function in patients with hepatorenal syndrome. However, it is unclear to what extent changes in serum creatinine during treatment may act as a surrogate for changes in mortality. We have performed a meta-analysis of randomized trials of vasoconstrictors assessing the association between changes in serum creatinine, taken as a continuous variable, and mortality, both while on treatment and during the follow-up period for survivors. Methods The electronic databases of PubMed, Web of Science and Embase were searched for randomized trials evaluating the efficacy of vasoconstrictor therapy for treatment of HRS type 1 or 2. The relative risk (RR) for mortality was calculated against delta creatinine. The proportion of treatment effect explained (PTE) was calculated for delta creatinine. Results Seven trials enrolling 345 patients were included. The correlation between delta creatinine and ln (RR) was moderately good (R2 = 0.61). The intercept and parameter estimate indicated a fall in creatinine while on treatment of 1 mg/dL resulted in a 27% reduction in RR for mortality compared to the control arm. In patients surviving the treatment period, a fall in creatinine while on treatment of 1 mg/dL resulted in a 16% reduction in RR for post-treatment mortality during follow-up. The PTE of delta creatinine for overall mortality was 0.91 and 0.26 for post-treatment mortality. Conclusions Changes in serum creatinine in response to vasoconstrictor therapy appear to be a valid surrogate for mortality, even in the period following the completion of treatment. PMID:26295585

  11. Altered Serum Uric Acid Level in Lichen Planus Patients

    PubMed Central

    Chakraborti, Goutam; Biswas, Rabindranath; Chakraborti, Sandip; Sen, Pradyot Kumar

    2014-01-01

    Background: Lichen planus (LP) is a common disorder whose etiopathogenesis is not clear. Recently, it has been suggested that increased reactive oxygen species (ROS) play important roles in the underlying mechanism of LP. Objectives: The principal aim of this study was to evaluate serum uric acid (UA) levels as a measure of the antioxidant defense status in LP patients. Methods: Serum UA levels were determined in 58 LP patients and 61 controls. Results: Serum UA levels were significantly decreased in patients with respect to controls. Moreover, serum UA level was decreased according to increasing duration of disease. Conclusions: The results of our study suggest that LP is associated with decrease of UA levels in serum. UA may be a potential, useful biomarker of antioxidant status in LP for elaboration of treatment strategy and monitoring. PMID:25484383

  12. Bilirubin and metamizol do not interfere with the randox enzymatic creatinine test. An evaluation of a new enzymatic creatinine determination method.

    PubMed

    Harmoinen, A P

    1996-12-01

    We evaluated the new commercially available enzymatic test kit for creatinine (Randox Laboratories Ltd. Ardmore, Crumlin, UK). The test correlated well with the reference HPLC method (yenz = 0.98x + 1.4; r = 1.00; n = 72). The correlations with the Jaffe method (yenz = 1.00x + 14.1; r = 0.99; n = 72) and the dry slide technique (yenz = 1.07x + 4.1; r = 1.00; n = 72) were also good, but these techniques gave slightly higher creatinine results than the HPLC or the Randox enzymatic method. This new test is insensitive to bilirubin interference. It has been reported that patients receiving metamizol showed unusually low values of creatinine, when determined enzymatically, but this drug does not interfere with the Randox method. The test evaluated is more specific than enzymatic methods published earlier and it provides an attractive alternative to the traditional picrate test. PMID:8986403

  13. Uric acid as radical scavenger and antioxidant in the heart.

    PubMed

    Becker, B F; Reinholz, N; Ozçelik, T; Leipert, B; Gerlach, E

    1989-11-01

    Uric acid (UA) is released from the heart of many species, including man, and its site of formation has been shown to be the microvascular endothelium. Since UA reacts with oxygen radicals in vitro, experiments were conducted on guinea pig hearts perfused with Krebs-Henseleit buffer (KHB) to evaluate whether the formation of UA could afford protection from damage by radicals and oxidants. The following results were obtained: (1) Upon addition of the hydroxyl radical scavenger DMSO to the perfusate, the coronary rate of release of endogenous uric acid was increased relative to the precursor purines. (2) UA was degraded during passage through the coronary system and also in KHB in vitro after addition of substances generating hydroxyl radicals or hypochlorite. Superoxide (O2-) radicals did not seem to react directly with UA, though UA concentration-dependently quenched the chemiluminescence generated from luminol in the presence of O2- and OH radicals. (3) Coronary dilation by acetylcholine (Ach) and sub-microM concentrations of adenosine, induced by both via endothelial mechanisms, was attenuated after prolonged inhibition of endothelial UA formation by allopurinol. Furthermore, the effect of Ach but not of adenosine proved acutely sensitive to methylene blue and O2-, substances known to inactivate EDRF. This finding suggests involvement of EDRF in Ach-mediated, but not in adenosine-induced dilatation of the intact coronary system. Exogenously applied UA prevented the impairment of vascular responses to Ach and adenosine caused by allopurinol, and to Ach upon generation of O2-. (4) Hearts performed more pressure-volume work and exhibited greater functional stability when perfused with KHB supplemented with UA in a physiological concentration.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2556684

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

    PubMed Central

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

    2012-01-01

    Background: Definitions of chronic kidney disease (CKD) in many catheterization laboratories have relied on the serum creatinine (Scr) rather than glomerular filtration rate (GFR). Regarding that CKD is the primary predisposing factor for contrast induced nephropathy (CIN), we compared the sensitivity of calculated GFR by 24-h Urine creatinine with Cockcroft-Gault (CG) equation and Scr level to define at risk patients for CIN who were undergone coronary angiography (CAG). Materials and Methods: Two hundred fifty four subjects who were candidate for CAG and had normal creatinine level were enrolled. Before CAG, GFR was calculated from a 24-h urine collection, CG equation and a single Scr sample regarding to previously described protocol. Contrast volume used for each case <100 ml. CIN was defined as a 0.5 mg/dL or 25% elevation in the Scr. Results: CIN occurred in 10.6%. Baseline GFR, the volume of contrast agent, and diabetes were the independent risk factors for CIN. GFR was less than 60 ml/min/1.73 m2 in 28% and 23.2% of patients regarding to 24-h urine creatinine and CG equation, respectively. In CIN prediction, 24-h urine creatinine estimated GFR had 85.2%, 59.3% and CG equation GFR had 78.9%, 81.1% sensitivity and specificity, respectively. Conclusion: Although, GFR estimated by CG equation has less sensitivity than GFR calculated from 24-h creatinine in CIN probability, but it is better than Scr alone and because of cost-effectiveness and convenience using of this method, we suggest at least using CG equation for GFR calculation before CIN, especially in diabetic and/or older than 60 years cases. PMID:23826014

  15. Day-to-Day Variation of the Urine Protein : Creatinine Ratio in Female Dogs with Stable Glomerular Proteinuria Caused

    E-print Network

    Boggess, May M.

    Day-to-Day Variation of the Urine Protein : Creatinine Ratio in Female Dogs with Stable Glomerular, and George E. Lees Background: Interpretation of serial urine protein : creatinine (UPC) values is confounded with other glomerulopathies. Key words: Creatinine; Power of mean model; Renal disease; Urine; Variance

  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. Synthesis and Characterization of Branched Poly(ester urea)s with Different Branch Density

    NASA Astrophysics Data System (ADS)

    Yu, Jiayi; Becker, Matthew

    2015-03-01

    A new class of L-phenylalanine-based poly(ester urea)s (PEU) was developed that possess tunable mechanical properties, water uptake ability and degradation rates. Our preliminary data has shown that 1,6-hexanediol L - phenylalanine-based poly(ester urea)s possesses an elastic modulus nearly double that of poly(lactic acid). My work details the synthesis of a series of L - phenylalanine-based poly(ester urea)s possessing a variation in diol chain length and in branch density and shows how these subtle structural differences influence the mechanical properties and in vitro biodegradation rates. The elastic moduli span a range of values that overlap with several currently clinically available degradable polymers. Increasingly the diol chain lengths increases the amount of flexible segment in the chemical structure, which results in reduced elastic modulus values and increased values of elongation at break. Increasing the amount of branch monomer incorporated into the system reduces the molecular entanglement, which also results in decreased elastic modulus values and increased values of elongation at break. The L - phenylalanine-based poly(ester urea)s also exhibited a diol length dependent degradation process that varied between 1-5 % over 16 weeks. Compared with PLLA, PEUs degrade more quickly and the rate can be tuned by changing the diol chain length. PEUs absorb more water and the water uptake ability can be tuned by changing the branch density. This work was supported by Akron Functional Materials Center.

  18. 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]...

  19. 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

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

    EPA Science Inventory

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

  1. Kidney injury biomarkers and urinary creatinine variability in nominally healthy adults

    EPA Science Inventory

    Environmental exposure diagnostics use creatinine concentrations in urine aliquots as the internal standard for dilution normalization of all other excreted metabolites when urinary excretion rate data are not available. This is a reasonable approach for healthy adults as creati...

  2. Measurement of creatinine in human plasma using a functional porous polymer structure sensing motif

    PubMed Central

    Nanda, Sitansu Sekhar; An, Seong Soo A; Yi, Dong Kee

    2015-01-01

    In this study, a new method for detecting creatinine was developed. This novel sensor comprised of two ionic liquids, poly-lactic-co-glycolic acid (PLGA) and 1-butyl-3-methylimidazolium (BMIM) chloride, in the presence of 2?,7?-dichlorofluorescein diacetate (DCFH-DA). PLGA and BMIM chloride formed a functional porous polymer structure (FPPS)-like structure. Creatinine within the FPPS rapidly hydrolyzed and released OH?, which in turn converted DCFH-DA to DCFH, developing an intense green color or green fluorescence. The conversion of DCFH to DCF+ resulted in swelling of FPPS and increased solubility. This DCF+-based sensor could detect creatinine levels with detection limit of 5 µM and also measure the creatinine in blood. This novel method could be used in diagnostic applications for monitoring individuals with renal dysfunction. PMID:26347475

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

    EPA Science Inventory

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

  4. Lower Serum Creatinine Is Associated with Low Bone Mineral Density in Subjects without Overt Nephropathy

    PubMed Central

    Huh, Ji Hye; Choi, Soo In; Lim, Jung Soo; Chung, Choon Hee; Shin, Jang Yel; Lee, Mi Young

    2015-01-01

    Background Low skeletal muscle mass is associated with deterioration of bone mineral density. Because serum creatinine can serve as a marker of muscle mass, we evaluated the relationship between serum creatinine and bone mineral density in an older population with normal renal function. Methods Data from a total of 8,648 participants (4,573 men and 4,075 postmenopausal women) aged 45–95 years with an estimated glomerular filtration rate >60 ml/min/1.73 m2 were analyzed from the Fourth Korea National Health and Nutrition Examination Survey (2008–2010). Bone mineral density (BMD) and appendicular muscle mass (ASM) were measured using dual-energy X-ray absorptiometry. Receiver operating characteristic curve analysis revealed that the cut points of serum creatinine for sarcopenia were below 0.88 mg/dl in men and 0.75 mg/dl in women. Subjects were divided into two groups: low creatinine and upper normal creatinine according to the cut point value of serum creatinine for sarcopenia. Results In partial correlation analysis adjusted for age, serum creatinine was positively associated with both BMD and ASM. Subjects with low serum creatinine were at a higher risk for low BMD (T-score ? –1.0) at the femur neck, total hip and lumbar spine in men, and at the total hip and lumbar spine in women after adjustment for confounding factors. Each standard deviation increase in serum creatinine was significantly associated with reduction in the likelihood of low BMD at the total hip and lumbar spine in both sexes (men: odds ratio (OR) = 0.84 [95% CI = 0.74?0.96] at the total hip, OR = 0.8 [95% CI = 0.68?0.96] at the lumbar spine; women: OR = 0.83 [95% CI = 0.73–0.95] at the total hip, OR=0.81 [95% CI = 0.67–0.99] at the lumbar spine). Conclusions Serum creatinine reflected muscle mass, and low serum creatinine was independently associated with low bone mineral density in subjects with normal kidney function. PMID:26207750

  5. A facile low-cost enzymatic paper-based assay for the determination of urine creatinine.

    PubMed

    Talalak, Kwanrutai; Noiphung, Julaluk; Songjaroen, Temsiri; Chailapakul, Orawon; Laiwattanapaisal, Wanida

    2015-11-01

    Creatinine is one of many markers used to investigate kidney function. This paper describes a low-cost enzymatic paper-based analytical device (enz-PAD) for determining urine creatinine. The disposable dead volumes of creatinine enzyme reagents from an automatic analyser cassette were utilised. Whatman No. 3 paper was cut into long rectangular shapes (4×40mm(2)) on which the enzyme reagents, R1 and R2, were adsorbed in two consecutive regions. The assay was performed by immersing test strips into urine samples contained in microwells to allow creatinine in the sample to react with immobilised active ingredients and, then, traverse via capillary action to the detection area where chromogen products accumulated. The method is based on hydrogen peroxide (H2O2) formation via creatinine conversion using creatininase, creatinase, and sarcosine oxidase. The liberated H2O2 reacts with 4-aminophenazone and 2,4,6-triiodo-3-hydroxybenzoic acid to form quinoneimine with a pink-red colour at the detection zone. The linear range of the creatinine assay was 2.5-25mgdL(-1) (r(2)=0.983), and the detection limit was 2.0mgdL(-1). The colorimetric enz-PAD for the creatinine assay was highly correlated with a conventional alkaline picrate method when real urine samples were evaluated (r(2)=0.977; n=40). This simple and nearly zero-cost paper-based device provides a novel alternative method for screening urinary creatinine and will be highly beneficial for developing countries. PMID:26452908

  6. Measurement of uric acid as a marker of oxygen tension in the lung.

    PubMed

    Elsayed, N M; Nakashima, J M; Postlethwait, E M

    1993-04-01

    Changes in O2 tension such as those associated with hypoxic ischemia or hyperoxia may potentially modulate purine nucleotide turnover and production of associated catabolites. We used an isolated perfused rat lung preparation to evaluate the effect of O2 tension on pulmonary uric acid production. Three O2 concentrations (21%, normoxia; 95%, hyperoxia; 0%, hypoxia) were utilized for both pulmonary ventilation and equilibration of recirculating perfusate. All gas mixtures contained 5% CO2 and were balanced with N2. We used Certified Virus Free Sprague-Dawley male rats weighting 250-300 g, four to five rats in each exposure regimen. After a 10-min equilibration period, we measured uric acid levels at 0 and 60 min in lung perfusate and at 60 min in lung tissue. After 60 min of ventilation/perfusion, we observed significant uric acid accumulation in both lung tissue (25-60%) and perfusate (8- to 10-fold) for all three O2 regimens. However, hypoxia produced substantially greater net uric acid concentrations (net = the difference between zero and 60 min) than either normoxia or hyperoxia (1.5-fold in lung tissue, and 2-fold in perfusate, respectively). The data suggest that pulmonary hypoxia results in greater purine catabolism leading to increased uric acid production. Vascular space uric acid, as measured in the recirculating perfusate, was proportional to lung weight changes (r = 0.99) with hypoxia exhibiting the greatest values, possibly reflecting a linkage between tissue perturbation and uric acid release. Thus, measurement of uric acid may serve as a useful marker of adenine nucleotide turnover and lung injury. PMID:8470901

  7. Uric Acid – Key Ingredient in the Recipe for Cardiorenal Metabolic Syndrome

    PubMed Central

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

    2013-01-01

    Elevated serum uric acid levels are a frequent finding in persons with obesity, hypertension, cardiovascular and kidney disease as well as in those with the cardiorenal metabolic syndrome (CRS). The increased consumption of a fructose-rich Western diet has contributed to the increasing incidence of the CRS, obesity and diabetes especially in industrialized populations. There is also increasing evidence that supports a causal role of high dietary fructose driving elevations in uric acid in association with the CRS. Animal and epidemiological studies support the notion that elevated serum uric acid levels play an important role in promoting insulin resistance and hypertension and suggest potential pathophysiological mechanisms that contribute to the development of the CRS and associated cardiovascular disease and chronic kidney disease. To this point, elevated serum levels of uric acid appear to contribute to impaired nitric oxide production/endothelial dysfunction, increased vascular stiffness, inappropriate activation of the renin-angiotensin-aldosterone system, enhanced oxidative stress, and maladaptive immune and inflammatory responses. These abnormalities, in turn, promote vascular, cardiac and renal fibrosis as well as associated functional abnormalities. Small clinical trials have suggested that uric acid-lowering therapies may be beneficial in such patients; however, a consensus on the treatment of asymptomatic hyperuricemia is lacking. Larger randomized controlled trials need to be performed in order to critically evaluate the beneficial effect of lowering serum uric acid in patients with the CRS and those with diabetes and/or hypertension. PMID:24454316

  8. Relationship between serum uric acid level and cardiometabolic risks in nondiabetic patients with schizophrenia.

    PubMed

    Rajan, Shirley; Zalpuri, Isheeta; Harrington, Amy; Cimpeanu, Cezar; Song, Xueqin; Fan, Xiaoduo

    2016-01-01

    This study examined the relationship between serum levels of uric acid and insulin resistance and metabolic syndrome in nondiabetic patients with schizophrenia. Outpatients diagnosed with schizophrenia or schizoaffective disorder participated in a multicenter, cross-sectional study. Fasting blood samples were obtained to determine serum levels of metabolic measures. A total of 135 patients were recruited for the study. A significant positive relationship was found between serum levels of uric acid and the homeostasis model of assessing insulin resistance (log transformed, r=0.394, P<0.001), and a significant negative relationship was found between serum levels of uric acid and low-density lipoprotein particle size (log transformed, r=-0.306, P=0.001) after controlling for potential confounding variables. Hierarchical multiple regression suggested that serum uric acid level is a significant predictor of insulin resistance (P=0.001) and of low-density lipoprotein particle size (P<0.015). Further, logistic regression showed that serum uric acid levels strongly predicted the condition of metabolic syndrome (odds ratio 0.630, 95% confidence interval 0.463-0.856, P=0.003). This study suggested that uric acid may be a clinically useful biomarker to indicate cardiometabolic risks in nondiabetic patients with schizophrenia. PMID:26550697

  9. Quantitative determination of uric acid using CdTe nanoparticles as fluorescence probes.

    PubMed

    Jin, Dongri; Seo, Min-Ho; Huy, Bui The; Pham, Quoc-Thai; Conte, Maxwell L; Thangadurai, Daniel; Lee, Yong-Ill

    2016-03-15

    A convenient enzymatic optical method for uric acid detection was developed based on the fluorescence quenching of ligand-capped CdTe nanoparticles by H2O2 which was generated from the enzymatic reaction of uric acid. The interactions between the CdTe nanoparticles capped with different ligands (glutathione, 3-mercaptopropionic acid, and thioglycerol) and H2O2 were investigated. The fluorescence quenching studies of GSH-capped CdTe nanoparticles demonstrated an excellent sensitivity to H2O2. The effects of uric acid, uricase and H2O2 on the fluorescence intensity of CdTe nanoparticles were also explored. The detection conditions, reaction time, pH value, incubation period and the concentration of uricase and uric acid were optimized. The detection limit of uric acid was found to be 0.10µM and the linear range was 0.22-6µM under the optimized experimental conditions. These results typify that CdTe nanoparticles could be used as a fluorescent probe for uric acid detection. PMID:26433069

  10. Heat Stress Nephropathy From Exercise-Induced Uric Acid Crystalluria: A Perspective on Mesoamerican Nephropathy.

    PubMed

    Roncal-Jimenez, Carlos; García-Trabanino, Ramón; Barregard, Lars; Lanaspa, Miguel A; Wesseling, Catharina; Harra, Tamara; Aragón, Aurora; Grases, Felix; Jarquin, Emmanuel R; González, Marvin A; Weiss, Ilana; Glaser, Jason; Sánchez-Lozada, Laura G; Johnson, Richard J

    2016-01-01

    Mesoamerican nephropathy (MeN), an epidemic in Central America, is a chronic kidney disease of unknown cause. In this article, we argue that MeN may be a uric acid disorder. Individuals at risk for developing the disease are primarily male workers exposed to heat stress and physical exertion that predisposes to recurrent water and volume depletion, often accompanied by urinary concentration and acidification. Uric acid is generated during heat stress, in part consequent to nucleotide release from muscles. We hypothesize that working in the sugarcane fields may result in cyclic uricosuria in which uric acid concentrations exceed solubility, leading to the formation of dihydrate urate crystals and local injury. Consistent with this hypothesis, we present pilot data documenting the common presence of urate crystals in the urine of sugarcane workers from El Salvador. High end-of-workday urinary uric acid concentrations were common in a pilot study, particularly if urine pH was corrected to 7. Hyperuricemia may induce glomerular hypertension, whereas the increased urinary uric acid may directly injure renal tubules. Thus, MeN may result from exercise and heat stress associated with dehydration-induced hyperuricemia and uricosuria. Increased hydration with water and salt, urinary alkalinization, reduction in sugary beverage intake, and inhibitors of uric acid synthesis should be tested for disease prevention. PMID:26455995

  11. De-crystallization of Uric Acid Crystals in Synovial Fluid Using Gold Colloids and Microwave Heating

    PubMed Central

    Kioko, Bridgit; Ogundolie, Taiwo; Adebiyi, Morenike; Ettinoffe, Yehnara; Rhodes, Caleb; Gordon, Brittney; Thompson, Nishone; Mohammed, Muzaffer; Abel, Biebele

    2015-01-01

    In this study, we demonstrated a unique application of our Metal-Assisted and Microwave-Accelerated Evaporative Crystallization (MA-MAEC) technique for the de-crystallization of uric acid crystals, which causes gout in humans when monosodium urate crystals accumulate in the synovial fluid found in the joints of bones. Given the shortcomings of the existing treatments for gout, we investigated whether the MA-MAEC technique can offer an alternative solution to the treatment of gout. Our technique is based on the use of metal nanoparticles (i.e., gold colloids) with low microwave heating to accelerate the de-crystallization process. In this regard, we employed a two-step process; (i) crystallization of uric acid on glass slides, which act as a solid platform to mimic a bone, (ii) de-crystallization of uric acid crystals on glass slides with the addition of gold colloids and low power microwave heating, which act as “nano-bullets” when microwave heated in a solution. We observed that the size and number of the uric acid crystals were reduced by >60% within 10 minutes of low power microwave heating. In addition, the use of gold colloids without microwave heating (i.e. control experiment) did not result in the de-crystallization of the uric acid crystals, which proves the utility of our MA-MAEC technique in the de-crystallization of uric acid. PMID:25745585

  12. An amperometric biosensor for uric acid determination prepared from uricase immobilized in polypyrrole film.

    PubMed

    Cete, Servet; Ya?ar, Ahmet; Arslan, Fatma

    2006-01-01

    In order to prepare a biosensor for the determination of uric acid, electropolymerization of pyrrole on Pt surface was carried out with an electrochemical cell containing pyrrole, ferrocene (as a electron mediator) and tetrabutylammonium tetrafluoroborat in acetonitrile by cyclic voltammetry between 0.0 and 1.0 V (vs. Ag/AgCl) at a scan rate of 50 mV/s upon Pt electrode. Uricase was immobilized by a glutaraldehyde/gelatine croslinking procedure on to polypyrrole film after the electropolymerization processes. The response of the biosensor against uric acid was measured after 330 seconds following the application of a constant potential of +0.7 V (vs. Ag/AgCl). The resulting biosensor exhibits excellent electrocatalysis for the uric acid. The amperometric determination is based on the electrochemical detection of H2O2, which is generated in enzymatic reaction of uric acid. The sensor responds to uric acid with a detection limit of 5.0 x 10(-7) M. The sensor remains relatively stable for 5 weeks. Interference effect were investigated on the amperometric response of the biosensor. Determination of uric acid was carried out in the biological fluids by biosensor. PMID:16809136

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

    PubMed

    Wood, Chris M; Liew, Hon Jung; De Boeck, Gudrun; Walsh, Patrick J

    2013-01-01

    The branchial mechanism of urea retention in elasmobranchs was investigated using an in vitro isolated-perfused head preparation, as well as in vivo samples, in the spiny dogfish shark. Both in vivo and in control saline perfusions containing 350 mmol L(-1) urea, calculated intracellular urea concentrations in gill epithelial cells were close to extracellular concentrations. Urea efflux to the external water fell only non-significantly, and calculated gill intracellular urea concentration did not change when perfusate urea concentration was reduced from 350 to 175 mmol?L(-1) with osmotic compensation by 175 mmol L(-1) mannitol. However, when the urea analogues thiourea or acetamide were present in the perfusate at concentrations equimolar (175 mmol L(-1)) to those of urea (175 mmol L(-1)), urea efflux rates were increased 4-fold and 6.5-fold respectively, and calculated gill intracellular urea concentrations were depressed by about 55%. Analogue efflux rates were similar to urea efflux rates. Previous studies have argued that either the basolateral or apical membranes provided the limiting permeability barrier, and/or that a back-transporter on the basolateral membranes of gill cells is responsible for urea retention. The present results provide new evidence that the apical membrane is the limiting factor in maintaining gill urea impermeability, and raise the prospect that a urea back-transporter, which can be competitively inhibited by thiourea and acetamide, operates at the apical membrane. PMID:23638369

  14. [Effects of urea and coated urea on harmful gases concentrations in plastic greenhouse].

    PubMed

    Zhou, Xihong; Zeng, Qingru; Mao, Xiaoyun; Zhang, Litian; Liao, Bohan; Tie, Baiqing; Liao, Zongwen

    2006-09-01

    With simulation test and plastic greenhouse experiment, this paper studied the effects of urea and minerals- coated urea on the soil pH and harmful gases concentrations in plastic greenhouse. The results showed that under simulated condition, the application of these'two N fertilizers led to an initial increase of soil pH, which reached the maximum (an increment of > 50%) within the first week and dropped to the initial level by the end of the fifth week. In plastic greenhouse, applying urea and coated urea resulted in the increase of NH3, NO2 and O3 concentrations. The daily volatilization amount of NH3 and NO2 was higher in urea treatment than in coated urea treatment, and the highest value in urea treatment was 42.36 microg x m(-3) x d(-1) for NH3, 41.95 microg x m(-3) x d(-1) for NO2, and 86.00 microg x m(-3) x d(-1) for O3. The volatilization intensity of NH3 and NO2 was influenced by temperature and sunlight, while the O3 concentration was influenced by sunlight. PMID:17147165

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

    SciTech Connect

    Cirio, A.; Boivin, R. )

    1990-05-01

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

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

    USGS Publications Warehouse

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

    1994-01-01

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

  17. Treatment of renal uric acid stone by extracorporeal shock wave lithotripsy combined with sodium bicarbonate: 2 case reports.

    PubMed

    Li, Hao-Yong; Lian, Pei-Yu; Zhou, Zhi-Yan; Song, Peng; Yan, Yi; Liu, Ji-Hong

    2015-01-01

    Uric acid stone is the most comment radiolucent renal stone with high recurrence rate, which would further cause acute upper urinary tract obstruction and kidney failure. Here we report two cases of renal uric acid stone from December 2012 to April 2013. One 43-year-old male patient suffered from chronic uric acid nephrolithiasis caused by the long-term indwelling of bilateral double-J stent. Another 69-year-old patient was also diagnosed with uric acid nephrolithiasis at the right kidney. Both patients were first treated with extracorporeal shock wave lithotripsy (ESWL), followed by 1.5% sodium bicarbonate dissolution therapy. After a week of the treatment, the uric acid stones in both patients were completely dissolved without retrograde infection. In summary, the use of ESWL and sodium bicarbonate dissolution therapy as a combined modality is a safe, effective, inexpensive treatment for uric acid nephrolithiasis. PMID:26550383

  18. Treatment of renal uric acid stone by extracorporeal shock wave lithotripsy combined with sodium bicarbonate: 2 case reports

    PubMed Central

    Li, Hao-Yong; Lian, Pei-Yu; Zhou, Zhi-Yan; Song, Peng; Yan, Yi; Liu, Ji-Hong

    2015-01-01

    Uric acid stone is the most comment radiolucent renal stone with high recurrence rate, which would further cause acute upper urinary tract obstruction and kidney failure. Here we report two cases of renal uric acid stone from December 2012 to April 2013. One 43-year-old male patient suffered from chronic uric acid nephrolithiasis caused by the long-term indwelling of bilateral double-J stent. Another 69-year-old patient was also diagnosed with uric acid nephrolithiasis at the right kidney. Both patients were first treated with extracorporeal shock wave lithotripsy (ESWL), followed by 1.5% sodium bicarbonate dissolution therapy. After a week of the treatment, the uric acid stones in both patients were completely dissolved without retrograde infection. In summary, the use of ESWL and sodium bicarbonate dissolution therapy as a combined modality is a safe, effective, inexpensive treatment for uric acid nephrolithiasis. PMID:26550383

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

    PubMed Central

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

    2011-01-01

    Urea transporters UT-A2 and UT-B are expressed in epithelia of thin descending limb of Henle's loop and in descending vasa recta, respectively. To study their role and possible interaction in the context of the urine concentration mechanism, a UT-A2 and UT-B double knockout (UT-A2/B knockout) mouse model was generated by targeted deletion of the UT-A2 promoter in embryonic stem cells with UT-B gene knockout. The UT-A2/B knockout mice lacked detectable UT-A2 and UT-B transcripts and proteins and showed normal survival and growth. Daily urine output was significantly higher in UT-A2/B knockout mice than that in wild-type mice and lower than that in UT-B knockout mice. Urine osmolality in UT-A2/B knockout mice was intermediate between that in UT-B knockout and wild-type mice. The changes in urine osmolality and flow rate, plasma and urine urea concentration, as well as non-urea solute concentration after an acute urea load or chronic changes in protein intake suggested that UT-A2 plays a role in the progressive accumulation of urea in the inner medulla. These results suggest that in wild-type mice UT-A2 facilitates urea absorption by urea efflux from the thin descending limb of short loops of Henle. Moreover, UT-A2 deletion in UT-B knockout mice partially remedies the urine concentrating defect caused by UT-B deletion, by reducing urea loss from the descending limbs to the peripheral circulation; instead, urea is returned to the inner medulla through the loops of Henle and the collecting ducts. PMID:21849488

  20. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  1. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  2. 21 CFR 862.1770 - Urea nitrogen test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  3. 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

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  5. Uric Acid Inhibition of Dipeptidyl Peptidase IV In Vitro is Dependent on the Intracellular Formation of Triuret

    PubMed Central

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

    2014-01-01

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

  6. 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...

  7. 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.

  8. Cystatin C versus Creatinine in Determining Risk Based on Kidney Function

    PubMed Central

    Shlipak, Michael G.; Matsushita, Kunihiro; Ärnlöv, Johan; Inker, Lesley A.; Katz, Ronit; Polkinghorne, Kevan R.; Rothenbacher, Dietrich; Sarnak, Mark J.; Astor, Brad C.; Coresh, Josef; Levey, Andrew S.; Gansevoort, Ron T.

    2014-01-01

    BACKGROUND Adding the measurement of cystatin C to that of serum creatinine to determine the estimated glomerular filtration rate (eGFR) improves accuracy, but the effect on detection, staging, and risk classification of chronic kidney disease across diverse populations has not been determined. METHODS We performed a meta-analysis of 11 general-population studies (with 90,750 participants) and 5 studies of cohorts with chronic kidney disease (2960 participants) for whom standardized measurements of serum creatinine and cystatin C were available. We compared the association of the eGFR, as calculated by the measurement of creatinine or cystatin C alone or in combination with creatinine, with the rates of death (13,202 deaths in 15 cohorts), death from cardiovascular causes (3471 in 12 cohorts), and end-stage renal disease (1654 cases in 7 cohorts) and assessed improvement in reclassification with the use of cystatin C. RESULTS In the general-population cohorts, the prevalence of an eGFR of less than 60 ml per minute per 1.73 m2 of body-surface area was higher with the cystatin C–based eGFR than with the creatinine-based eGFR (13.7% vs. 9.7%). Across all eGFR categories, the reclassification of the eGFR to a higher value with the measurement of cystatin C, as compared with creatinine, was associated with a reduced risk of all three study outcomes, and reclassification to a lower eGFR was associated with an increased risk. The net reclassification improvement with the measurement of cystatin C, as compared with creatinine, was 0.23 (95% confidence interval [CI], 0.18 to 0.28) for death and 0.10 (95% CI, 0.00 to 0.21) for end-stage renal disease. Results were generally similar for the five cohorts with chronic kidney disease and when both creatinine and cystatin C were used to calculate the eGFR. CONCLUSIONS The use of cystatin C alone or in combination with creatinine strengthens the association between the eGFR and the risks of death and end-stage renal disease across diverse populations. (Funded by the National Kidney Foundation and others.) PMID:24004120

  9. 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 ...

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

    PubMed Central

    2011-01-01

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

  11. Creatinine measurements in 24 h urine by liquid chromatography--tandem Mass Spectrometry.

    PubMed

    Park, Eun-Kee; Watanabe, Takaho; Gee, Shirley J; Schenker, Marc B; Hammock, Bruce D

    2008-01-23

    A simple, sensitive, and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining urinary creatinine was developed and used to evaluate 24 h urine samples collected during an exposure study. Urine (1 microL) was diluted with methanol and then directly applied to LC-MS/MS. Under electrospray ionization (ESI) conditions, the transition molecules of creatinine and creatinine- d3 were observed at m/ z 114 > 44 and m/ z 117 > 47, respectively. The retention time of creatinine was 0.59 min. The linear range was 1-2000 ng/mL, with a detection limit in urine of 1 ng/mL. LC-MS/MS and colorimetric end-point methods were significantly associated ( R2 = 0.8785, p < 0.0001). The LC-MS/MS method to determine creatinine in 24 h urine samples had shorter retention times, was more sensitive, reliable, reproducible, simple, selective, and used a smaller sample size than other LC-MS/MS or commercial methods. PMID:18092755

  12. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium nitrate-urea complex. 176.320 Section 176... Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a..., packaging, transporting, or holding food, subject to the provisions of this section. (a) Sodium...

  13. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium... the provisions of this section. (a) Sodium nitrate-urea complex is a clathrate of approximately...

  14. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium... the provisions of this section. (a) Sodium nitrate-urea complex is a clathrate of approximately...

  15. 76 FR 77015 - Solid Urea From Russia and Ukraine

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-09

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

  16. 76 FR 15339 - Solid Urea From Russia and Ukraine

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-21

    ...340-H (Third Review)] Solid Urea From Russia and Ukraine AGENCY: United States International...antidumping duty orders on solid urea from Russia and Ukraine...antidumping duty orders on solid urea from Russia and Ukraine would be likely to lead...

  17. 75 FR 74746 - Solid Urea From Russia and Ukraine

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-01

    ...340-H (Third Review)] Solid Urea From Russia and Ukraine AGENCY: United States International...antidumping duty orders on solid urea from Russia and Ukraine...antidumping duty orders on solid urea from Russia and Ukraine would be likely to lead...

  18. 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. ...

  19. Investigating the Hydrogen-Bonding Model of Urea Denaturation

    E-print Network

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

  20. Comparison between Procalcitonin, Brain Natriuretic Peptide, and Uric Acid in Children with Cardiomyopathy and Controls

    PubMed Central

    Noori, Noor Mohammad; Mahjoubifard, Maziar; Shahramian, Iraj; Teimouri, Alireza; Jahangirifard, Alireza

    2015-01-01

    Objective. This study was performed to determine the level of procalcitonin, Brain Natriuretic Peptide (BNP), and uric acid in children with cardiomyopathy in comparison with controls and the association with echocardiographic findings. Methods. The levels of BNP, procalcitonin, and serum uric acid were measured and the amounts of biomarkers compared with echocardiographic findings. Results. In this study mean age of participants was the same (p=0.321). The majority of echocardiographic indices in left and right heart have different means in case and controls (p<0.05). Means of BNP, procalcitonin, and uric acid were 213.814 ± 309.601, 9.326 ± 3.881, and 6.846 ± 1.814 for case group and 2.76 ± 1.013, 1.851 ± 1.466, and 3.317 ± 0.924 for control (p<0.001), respectively. In the patients group there was relationship of Ross classification with BNP (?2 = 15.845, p<0.05) and with age (?2 = 8.946, p<0.05). For uric acid and procalcitonin no significant relationships were observed. Conclusions. procalcitonin, uric acid, and BNP had significant relationship with many echocardiographic findings in participants. For patients, procalcitonin did not show correlation. The severity of illness based on the Ross classification showed significant correlation with BNP level and age in patients. PMID:26495299

  1. Low Serum Levels of Uric Acid are Associated With Development of Poststroke Depression.

    PubMed

    Gu, Yingying; Han, Bin; Wang, Liping; Chang, Yaling; Zhu, Lin; Ren, Wenwei; Yan, Mengjiao; Zhang, Xiangyang; He, Jincai

    2015-11-01

    Poststroke depression (PSD) is a frequent complication of stroke that has been associated with poorer outcome of stroke patients. This study sought to examine the possible association between serum uric acid levels and the development of PSD.We recruited 196 patients with acute ischemic stroke and 100 healthy volunteers. Serum uric acid levels were tested by uricase-PAP method within 24?hr after admission. Neuropsychological evaluations were conducted at 3-month poststroke. The 17-item Hamilton Depression Scale was used to assess depressive symptoms. Diagnosis of PSD was made in accordance with DSM-IV criteria for depression. Multivariate analyses were conducted using logistic regression models.Fifty-six patients (28.6%) were diagnosed as having PSD at 3 months. PSD patients showed significantly lower levels of uric acid at baseline as compared to non-PSD patients (237.02?±?43.43 vs 309.10?±?67.44??mol/L, t?=?-8.86, P?uric acid levels (?239.0 and ?328.1??mol/L) were independently associated with the development of PSD (OR, 7.76; 95% confidence interval [CI], 2.56-23.47, P?uric acid levels at admission are found to be correlated with PSD and may predict its development at 3 months after stroke. PMID:26559256

  2. The role of uric acid in the insulin resistance in children and adolescents with obesity

    PubMed Central

    de Miranda, Josiane Aparecida; Almeida, Guilherme Gomide; Martins, Raissa Isabelle Leăo; Cunha, Mariana Botrel; Belo, Vanessa Almeida; dos Santos, José Eduardo Tanus; Mourăo-Júnior, Carlos Alberto; Lanna, Carla Márcia Moreira

    2015-01-01

    Objective: To investigate the association between serum uric acid levels and insulin resistance in children and adolescents with obesity. Methods: Cross-sectional study with 245 children and adolescents (134 obese and 111 controls), aged 8-18 years. The anthropometric variables (weight, height and waist circumference), blood pressure and biochemical parameters were collected. The clinical characteristics of the groups were analyzed by t-test or chi-square test. To evaluate the association between uric acid levels and insulin resistance the Pearson's test and logistic regression were applied. Results: The prevalence of insulin resistance was 26.9%. The anthropometric variables, systolic and diastolic blood pressure and biochemical variables were significantly higher in the obese group (p<0.001), except for the high-density-lipoprotein cholesterol. There was a positive and significant correlation between anthropometric variables and uric acid with HOMA-IR in the obese and in the control groups, which was higher in the obese group and in the total sample. The logistic regression model that included age, gender and obesity, showed an odds ratio of uric acid as a variable associated with insulin resistance of 1.91 (95%CI 1.40-2.62; puric acid showed a positive statistical correlation with insulin resistance and it is associated with and increased risk of insulin resistance in obese children and adolescents. PMID:26300523

  3. The relative contribution of urine extravasation to elevate plasma creatinine levels in acute unilateral ureteral obstruction

    PubMed Central

    Rosenzweig, Barak; Pinthus, Jehonathan H.; Kleinmann, Nir; Joffe, Erel; Erlich, Tomer; Fridman, Eddie; Winkler, Harry; Mor, Yoram; Ramon, Jacob; Dotan, Zohar A.

    2015-01-01

    Introduction: Rising levels of plasma creatinine in the setting of acute unilateral ureteral obstruction (AUUO) often reflects acute renal failure, mandating kidney drainage. We hypothesize that re-absorption of peri-renal urine extravasation (PUE), a common result of UUO, contributes significantly to the elevation in plasma creatinine, rendering the latter an inaccurate benchmark for renal function. We explored this hypothesis in a rat model of AUUO and PUE. Methods: In total, 20 rats were equally divided into 4 groups. Groups 1 and 2 underwent unilateral ligation of the ureter with infiltration of rat’s urine (index group) or saline (control) into the peri-renal space. Two additional control groups underwent peri-renal injection of either urine or saline without AUUO. Plasma creatinine levels were determined immediately prior to the procedure (T0), and hourly for 3 hours (T1, T2 and T3). Renal histology was investigated after 3 hours. Results: Rats in the index group had a significantly greater increase in plasma creatinine levels over 3 hours compared to all other groups (p < 0.05). At T3, average plasma creatinine levels for the index group increased by 96% (0.49 ± 0.18 mg/dL) compared to 46% (0.23 ± 0.06 mg/dL increase) in the AUUO and saline group, and less than 15% rise in both the non-obstructed control groups. Our study limitations includes lack of spontaneous PUE and intraperitoneal surgical approach. Conclusions: Absorption of peri-renal urine in the presence of AUUO is a significant contributor to rising plasma creatinine levels, beyond those attributable to the obstruction alone, and may overestimate the extent of the true renal functional impairment. PMID:26279711

  4. Creatinine generation is reduced in patients requiring continuous venovenous hemodialysis and independently predicts mortality

    PubMed Central

    Wilson, Francis P.; Sheehan, Jessica M.; Mariani, Laura H.; Berns, Jeffrey S.

    2012-01-01

    Background Existing systems for grading severity of acute kidney injury (AKI) rely on a change of serum creatinine concentration over a defined time interval. The rate of change in serum creatinine increases by degree of reduction in glomerular filtration rate, but is mitigated by low creatinine generation rate (CGR). Failure to appreciate variation in CGR may lead to erroneous conclusions regarding severity of AKI and distorted predictions regarding patient outcomes based on AKI severity. Methods Cohort study of 103 patients who received continuous venovenous hemodialysis (CVVHD) over a 2-year period in a tertiary care hospital setting. Study participants entered the cohort when they were anuric, receiving a stable and uninterrupted dose of CVVHD with serum creatinine in steady state. They were followed until hospital discharge. CGR was measured based on dialyzate effluent volume and effluent creatinine concentration (prospective cohort) and via effluent volume and serum creatinine concentration (retrospective cohort). Results CGR (mean 10.5, range 1.7–22.4 mg/kg/day) was substantially lower in this patient population than what would be predicted from existing equations. Correlates of CGR in multivariable analysis included the length of hospitalization prior to measurement and presence of an oncologic diagnosis. Lower CGR was independently associated with in-hospital mortality in unadjusted analysis and after multivariable adjustment for measures of severity of illness. Conclusions Grading systems for severity of AKI fail to account for variation in CGR, limiting their ability to predict relevant outcomes. Calculation of CGR is superior to other risk metrics in predicting hospital mortality in this population. PMID:22273668

  5. 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. PMID:26136188

  6. 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.

  7. Kidney injury biomarkers and urinary creatinine variability in nominally healthy adults.

    PubMed

    Stiegel, M A; Pleil, J D; Sobus, J R; Angrish, M M; Morgan, M K

    2015-09-01

    Environmental exposure diagnostics use creatinine concentrations in urine aliquots as the internal standard for dilution normalization of all other excreted metabolites when urinary excretion rate data are not available. This is a reasonable approach for healthy adults as creatinine is a human metabolite that is continually produced in skeletal muscles and presumably excreted in the urine at a stable rate. However, creatinine also serves as a biomarker for glomerular filtration rate (efficiency) of the kidneys, so undiagnosed kidney function impairment could affect this commonly applied dilution calculation. The United States Environmental Protection Agency (US EPA) has recently conducted a study that collected approximately 2600 urine samples from 50 healthy adults, aged 19-50 years old, in North Carolina in 2009-2011. Urinary ancillary data (creatinine concentration, total void volume, elapsed time between voids), and participant demographic data (race, gender, height, and body weight) were collected. A representative subset of 280 urine samples from 29 participants was assayed using a new kidney injury panel (KIP). In this article, we investigated the relationships of KIP biomarkers within and between subjects and also calculated their interactions with measured creatinine levels. The aims of this work were to document the analytical methods (procedures, sensitivity, stability, etc.), provide summary statistics for the KIP biomarkers in "healthy" adults without diagnosed disease (distribution, fold range, central tendency, variance), and to develop an understanding as to how urinary creatinine level varies with respect to the individual KIP proteins. Results show that new instrumentation and data reduction methods have sufficient sensitivity to measure KIP levels in nominally healthy urine samples, that linear regression between creatinine concentration and urinary excretion explains only about 68% of variability, that KIP markers are poorly correlated with creatinine (r(2) ? 0.34), and that statistical outliers of KIP markers are not random, but are clustered within certain subjects. In addition, we interpret these new adverse outcome pathways based in vivo biomarkers for their potential use as intermediary chemicals that may be diagnostic of kidney adverse outcomes to environmental exposure. PMID:26616147

  8. Serum uric acid concentrations and SLC2A9 genetic variation in Hispanic children: The Viva La Familia Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated concentrations of serum uric acid are associated with increased risk of gout and renal and cardiovascular diseases. Genetic studies in adults have consistently identified associations of solute carrier family 2, member 9 (SLC2A9), polymorphisms with variation in serum uric acid. However, it...

  9. Urea-induced denaturation of PreQ1-riboswitch

    E-print Network

    Jeseong Yoon; D. Thirumalai; Changbong Hyeon

    2013-07-20

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

  10. Design and Simulation of a Microfluidic Blood-Plasma Separation Chip Using Microchannel Structures

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    ; and metabolic waste products, such as urea, uric acid creatinine from the kidneys, and bilirubin from the gall for the separation of whole blood into blood cells and cell-free plasma are currently based on large facility the efficiency of plasma extraction. Based on the numerical simulations, the design with both converging

  11. HOME AIR NICOTINE LEVELS AND URINE COTININE-CREATININE RATIOS IN PRESCHOOL CHILDREN

    EPA Science Inventory

    We studied urine cotinine excretion in 27 children who attended a research day care center to determine the extent of correlation between urine cotinine-creatinine ratios (CCR) and intensity of nicotine exposure in the home. verage nicotine levels in home air were determined by a...

  12. Adjustment of creatinine-adjusted value to urine flow rate in lead workers.

    PubMed

    Sata, F; Araki, S

    1996-01-01

    Two male lead workers, aged 57 and 51 y, were studied to compare the urinary flow/creatinine-adjusted values published earlier by Araki et al. and by Greenberg and Levine. We collected 24-h urine samples once a month for 31 mo and 16 mo for workers 1 and 2, respectively. The workers' urinary excretions of lead, delta-aminolevulinic acid, and coproporphyrin were measured. No significant correlations between urine flow rate and urinary flow/creatinine-adjusted values published by Araki et al. for the three substances were found for these two workers. However, urinary flow/creatinine-adjusted values presented by Greenberg and Levine for lead and delta-aminolevulinic acid were correlated positively with urine flow rate in the two workers, and their adjusted value for coproporphyrin was correlated positively with urine flow rate in one of the workers. We concluded that use of the urinary flow/creatinine-adjusted value by Greenberg and Levine for biological monitoring poses a problem because of the theoretical fallacy. PMID:8757415

  13. Normalization of urinary biomarkers to creatinine during changes in glomerular filtration rate

    PubMed Central

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

    2011-01-01

    Urinary biomarkers, such as albumin and other markers of kidney injury, are frequently reported as a normalized ratio to urinary creatinine (UCr) concentration [UCr] to control for variations in urine flow rate. The implicit assumption is that UCr excretion is constant across and within individuals, such that changes in the ratio will reflect changes in biomarker excretion. Using computer simulations of creatinine kinetics, we found that normalized levels of a biomarker reflecting tubular injury can be influenced by dynamic changes in the UCr excretion rate when the glomerular filtration rate changes. Actual timed urine collections from hospitalized patients with changing glomerular filtration rates and/or critical illness exhibited variability in UCr excretion rates across and within individuals. Normalization by [UCr] may, therefore, result in an underestimation or overestimation of the biomarker excretion rate depending on the clinical context. Lower creatinine excretion in the setting of acute kidney injury or poor renal allograft function may amplify a tubular injury biomarker signal, thereby increasing its clinical utility. The variability of creatinine excretion, however, will complicate the determination of a threshold value for normalized biomarkers of acute or chronic kidney disease, including albumin. Thus, we suggest that the most accurate method to quantify biomarkers requires the collection of timed urine specimens to estimate the actual excretion rate, provided that the biomarker is stable over the period of collection. This ideal must be balanced, however, against practical considerations. PMID:20555318

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

    PubMed Central

    Agarwal, Banwari; Davenport, Andrew

    2014-01-01

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

  15. Comparison between Cystatin C- and Creatinine-Estimated Glomerular Filtration Rate in Cardiology Patients

    PubMed Central

    Ĺkerblom, Axel; Helmersson-Karlqvist, Johanna; Flodin, Mats; Larsson, Anders

    2015-01-01

    Objective Estimation of the glomerular filtration rate (GFR) is essential for identification, evaluation and risk prediction in patients with kidney disease. Estimated GFR (eGFR) is also needed for the correct dosing of drugs eliminated by the kidneys and to identify high-risk individuals in whom coronary angiography or other procedures may lead to kidney failure. Both cystatin C and creatinine are used for the determination of GFR, and we aimed to investigate if eGFR by the two methods differ in cardiology patients. Methods We compared cystatin C and creatinine (CKD-EPI) eGFR calculated from the same request from a cardiology outpatient unit (n = 2,716), a cardiology ward (n = 980), a coronary care unit (n = 1,464), and an advanced coronary care unit (n = 518) in an observational, cross-sectional study. Results The median creatinine eGFR results are approximately 10 ml/min/1.73 m2 higher than the median cystatin C eGFR that is up to 90 ml/min/1.73 m2, irrespective of the level of care. Creatinine eGFR resulted in a less advanced eGFR category in the majority of patients with a cystatin C eGFR <60 ml/min/1.73 m2. Conclusions Our study demonstrates a difference between creatinine and cystatin C eGFR in cardiology patients. It is important to be aware of which marker is used for the reported eGFR to minimize erroneous interpretations of the test results, as this could lead to under- or overmedication. Further studies are needed to determine the best method of estimating the GFR in cardiology units.

  16. 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…

  17. Urea perturbation and the reversibility of nucleohistone conformation

    PubMed Central

    Chang, Catherine; Li, Hsueh Jei

    1974-01-01

    Urea effect on conformation and thermal stabilities in nucleohistone and NaCl-treated partially dehistonized nucleohistones has been studied by circular dichroism (CD) and thermal denaturation. Urea imposes a CD change at 278mm of DNA base pairs in native and NaCl-treated nucleohistones which can be decomposed into two parts: a decrease in ??278 for histone-free base pairs and an increase for histone-bound base pairs. The reduction by urea of ??220 of bound histones is approximately proportional to the increase of ??278 of histone-bound base pairs. Urea also lowers the melting temperatures of base pairs both free and bound by histones. The presence of urea indeed destroys the secondary structure of bound histones, causing changes in the conformation and thermal stabilities of histone-bound base pairs in nucleohistone. Such a urea perturbation on nucleohistone conformation is reversible. PMID:10793727

  18. Volatile disinfection byproducts resulting from chlorination of uric acid: implications for swimming pools.

    PubMed

    Lian, Lushi; E, Yue; Li, Jing; Blatchley, Ernest R

    2014-03-18

    Cyanogen chloride (CNCl) and trichloramine (NCl3) are important disinfection byproducts in chlorinated swimming pools. However, some unknowns exist regarding the precursors of their formation. In this study, uric acid is shown to be an efficient precursor to formation of CNCl and NCl3. The molar yields of CNCl and NCl3 were observed to be as high as 44% (pH = 6.0, chlorine/precursor molar ratio [Cl/P] = 6.4) and 108% (pH = 7.0, Cl/P = 30), respectively, both being strong functions of Cl/P, pH, and temperature. Analysis of swimming pool water samples, combined with the results of experiments involving chlorination of uric acid, and chlorination of body fluid analog mixtures, indicated that uric acid chlorination may account for a large fraction of CNCl formation in swimming pools. Moreover, given that uric acid introduction to pools is attributable to urination, a voluntary action for most swimmers, these findings indicate important benefits to pool water and air chemistry that could result from improved hygiene habits on the part of swimmers. PMID:24568660

  19. 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

  20. Serum Uric Acid, Hyperuricemia and Body Mass Index in Children and Adolescents with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Lin, Jin-Ding; Lin, Pei-Ying; Lin, Lan-Ping; Hsu, Shang-Wei; Yen, Chia-Feng; Fang, Wen-Hui; Wu, Sheng-Ru; Chien, Wu-Chien; Loh, Ching-Hui; Chu, Cordia M.

    2009-01-01

    The aims of the preset study were to describe the profile of serum uric acid, the prevalence of hyperuricemia and its risk factors among children and adolescents with intellectual disabilities. We conducted a cross-sectional study of 941 children and adolescents with intellectual disabilities (aged 4-18 years) who participated in annual health…

  1. Preferential interactions in aqueous solutions of urea and KCl.

    PubMed

    Hong, Jiang; Capp, Michael W; Anderson, Charles F; Record, M Thomas

    2003-09-01

    A quantitative characterization of the thermodynamic effects due to interactions of salt ions and urea in aqueous solution is needed for rigorous analyses of the effects of changing urea concentration on biopolymer processes in solutions that also contain salt. Therefore, we investigate preferential interactions in aqueous solutions containing KCl and urea by using vapor pressure osmometry (VPO) to measure osmolality as a function of the molality of urea (component 3) over the range 0.09urea or KCl, we evaluate approximately the chemical potential derivative micro(23)=( partial differential micro(KCl)/ partial differential m(urea))(T,P,m(KCl))=( partial differential micro(urea)/ partial differential m(KCl))(T,P,m(urea))= micro(32) and hence the preferential interaction coefficients Gammamicro(3) and Gammamicro(1),micro(3). These results show that for water-KCl-urea solutions neither of these coefficients is determined primarily by contributions from thermodynamic nonideality to micro(23). In aqueous solutions containing a biopolymer and a small solute, the contribution of ideal mixing entropy to micro(23) is negligible in comparison with the experimental uncertainty, whereas in KCl-urea solutions the contribution due to ideal mixing entropy accounts for at least half of the magnitude of micro(23). For comparison, we analyze literature data for NaCl-urea interactions and find again that nonideality makes a smaller contribution to micro(23) than does ideal mixing entropy. In contrast, for aqueous solutions of urea and the protein bovine serum albumin, the experimentally determined contribution of nonideality to micro(23) exceeds the contribution of ideal mixing by a factor of approximately 2 x 10(2). PMID:14499915

  2. Impact on creatinine renal clearance by the interplay of multiple renal transporters: a case study with INCB039110.

    PubMed

    Zhang, Yan; Warren, Mark S; Zhang, Xuexiang; Diamond, Sharon; Williams, Bill; Punwani, Naresh; Huang, Jane; Huang, Yong; Yeleswaram, Swamy

    2015-04-01

    Serum creatinine is commonly used as a marker of renal function, but increases in serum creatinine might not represent changes in glomerular filtration rate (GFR). INCB039110 (2-(3-(4-(7H-pyrrolo[2,3-day]pyrimidin-4-yl)-1H-pyrazol-1-yl)-1-(1-(3-fluoro-2-(trifluoromethyl)isonicotinoyl)piperidin-4-yl)azetidin-3-yl)acetonitrile) is an inhibitor of the Janus kinases (JAKs) with selectivity for JAK1. In a phase 1 study, a modest and reversible increase in serum creatinine was observed after treatment with INCB039110. However, a dedicated renal function study with INCB039110, assessed by iohexol plasma clearance, conducted in healthy volunteers indicated no change in GFR. In vitro studies were therefore conducted to investigate the interaction of INCB039110 with five transporters that are likely involved in the renal clearance of creatinine. Cell systems expressing individual or multiple transporters were used, including a novel quintuple-transporter model OAT2/OCT2/OCT3/MATE1/MATE2-K. INCB039110 potently inhibited OCT2-mediated uptake of creatinine as well as MATE1-/MATE2-K-mediated efflux of creatinine. Given the interactions of INCB039110 with multiple transporters affecting creatinine uptake and efflux, an integrated system expressing all five transporters was sought; in that system, INCB039110 caused a dose-dependent decrease in transcellular transport of creatinine with weaker net inhibition compared with the effects on individual transporters. In summary, a molecular mechanism for the increase in serum creatinine by INCB039110 has been established. These studies also underline the limitations of using serum creatinine as a marker of renal function. PMID:25605813

  3. Uric Acid-Induced Adipocyte Dysfunction Is Attenuated by HO-1 Upregulation: Potential Role of Antioxidant Therapy to Target Obesity.

    PubMed

    Sodhi, Komal; Hilgefort, Jordan; Banks, George; Gilliam, Chelsea; Stevens, Sarah; Ansinelli, Hayden A; Getty, Morghan; Abraham, Nader G; Shapiro, Joseph I; Khitan, Zeid

    2016-01-01

    Increased uric acid levels have been implicated in the pathogenesis of metabolic syndrome. To examine the mechanisms by which this occurs, we hypothesized that an increase in heme oxygenase 1, a potent antioxidant gene, will decrease uric acid levels and adipocyte dysfunction via suppression of ROS and xanthine oxidase (XO) levels. We examined the effect of uric acid on adipogenesis in human mesenchymal stem cells (MSCs) in the presence and absence of cobalt protoporphyrin (CoPP), an HO-1 inducer, and tin mesoporphyrin (SnMP), an HO activity inhibitor. Uric acid increased adipogenesis by increasing NADPH oxidase expression and elevation in the adipogenesis markers C/EBP?, PPAR?, and Mest, while decreasing small lipid droplets and Wnt10b levels. We treated MSCs with fructose, a fuel source that increases uric acid levels. Our results showed that fructose increased XO expression as compared to the control and concomitant treatment with CoPP significantly decreased XO expression and uric acid levels. These beneficial effects of CoPP were reversed by SnMP, supporting a role for HO activity in mediating these effects. These findings demonstrate that increased levels of HO-1 appear crucial in modulating the phenotype of adipocytes exposed to uric acid and in downregulating XO and NADPH oxidase levels. PMID:26681956

  4. Conversion of Uric Acid into Ammonium in Oil-Degrading Marine Microbial Communities: a Possible Role of Halomonads.

    PubMed

    Gertler, Christoph; Bargiela, Rafael; Mapelli, Francesca; Han, Xifang; Chen, Jianwei; Hai, Tran; Amer, Ranya A; Mahjoubi, Mouna; Malkawi, Hanan; Magagnini, Mirko; Cherif, Ameur; Abdel-Fattah, Yasser R; Kalogerakis, Nicolas; Daffonchio, Daniele; Ferrer, Manuel; Golyshin, Peter N

    2015-10-01

    Uric acid is a promising hydrophobic nitrogen source for biostimulation of microbial activities in oil-impacted marine environments. This study investigated metabolic processes and microbial community changes in a series of microcosms using sediment from the Mediterranean and the Red Sea amended with ammonium and uric acid. Respiration, emulsification, ammonium and protein concentration measurements suggested a rapid production of ammonium from uric acid accompanied by the development of microbial communities containing hydrocarbonoclastic bacteria after 3 weeks of incubation. About 80 % of uric acid was converted to ammonium within the first few days of the experiment. Microbial population dynamics were investigated by Ribosomal Intergenic Spacer Analysis and Illumina sequencing as well as by culture-based techniques. Resulting data indicated that strains related to Halomonas spp. converted uric acid into ammonium, which stimulated growth of microbial consortia dominated by Alcanivorax spp. and Pseudomonas spp. Several strains of Halomonas spp. were isolated on uric acid as the sole carbon source showed location specificity. These results point towards a possible role of halomonads in the conversion of uric acid to ammonium utilized by hydrocarbonoclastic bacteria. PMID:25916483

  5. Uric Acid-Induced Adipocyte Dysfunction Is Attenuated by HO-1 Upregulation: Potential Role of Antioxidant Therapy to Target Obesity

    PubMed Central

    Sodhi, Komal; Hilgefort, Jordan; Banks, George; Gilliam, Chelsea; Stevens, Sarah; Ansinelli, Hayden A.; Getty, Morghan; Abraham, Nader G.; Shapiro, Joseph I.

    2016-01-01

    Increased uric acid levels have been implicated in the pathogenesis of metabolic syndrome. To examine the mechanisms by which this occurs, we hypothesized that an increase in heme oxygenase 1, a potent antioxidant gene, will decrease uric acid levels and adipocyte dysfunction via suppression of ROS and xanthine oxidase (XO) levels. We examined the effect of uric acid on adipogenesis in human mesenchymal stem cells (MSCs) in the presence and absence of cobalt protoporphyrin (CoPP), an HO-1 inducer, and tin mesoporphyrin (SnMP), an HO activity inhibitor. Uric acid increased adipogenesis by increasing NADPH oxidase expression and elevation in the adipogenesis markers C/EBP?, PPAR?, and Mest, while decreasing small lipid droplets and Wnt10b levels. We treated MSCs with fructose, a fuel source that increases uric acid levels. Our results showed that fructose increased XO expression as compared to the control and concomitant treatment with CoPP significantly decreased XO expression and uric acid levels. These beneficial effects of CoPP were reversed by SnMP, supporting a role for HO activity in mediating these effects. These findings demonstrate that increased levels of HO-1 appear crucial in modulating the phenotype of adipocytes exposed to uric acid and in downregulating XO and NADPH oxidase levels. PMID:26681956

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

    PubMed

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

    2014-10-01

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

  7. Relationship between urinary albumin and albumin/creatinine ratio during normal pregnancy and pre-eclampsia.

    PubMed

    Risberg, A; Larsson, A; Olsson, K; Lyrenäs, S; Sjöquist, M

    2004-01-01

    Pre-eclampsia is a serious complication of pregnancy and it is important to detect the condition as early as possible. Albuminuria is an important symptom of pre-eclampsia and repeated urine analyses to screen for the condition are part of the standard antenatal care. The purpose of this study was to investigate whether measurement of the urine albumin/creatinine ratio in spot samples could be a complement to the dipstick method and could reduce the need for 24-h urine collections. Urine samples were collected for 24 h in weeks 12, 24 and 36 of pregnancy from both normotensive women and women who developed hypertension or who had pregnancy-induced hypertension (PIH) when they entered the study. The 24-h albumin excretion was significantly correlated to the albumin/creatinine ratio in all measurements (Pearson correlation coefficient). In week 12, the values were: n = 44, r = 0.964, p < 0.001 (normotensive group) and in the PIH group: n = 8, r = 0.789, p < 0.05. In week 24, the correlation values were r = 1.0 and p < 0.001 in both the normotensive group (n = 41) and in the PIH group (n = 11). In week 36 the correlation values were r = 0.791 and p < 0.001 in the normotensive group (n = 39) and r = 1.0 and p < 0.001 in the PIH group (n = 16). Microalbuminuria was defined as urine albumin excretion higher than 30 mg/24 h and this corresponded to an albumin/creatinine ratio of 2.9. Microalbuminuria was found in three persons in the PIH group and in two persons in the normotensive group. Overt albuminuria (> 300 mg/24 h) was found in one of the 46 normotensive women (2%) and in 3 of the 19 PIH women (16%). In all these women the high albumin values had been detected by using the albumin/creatinine ratio method. In conclusion, it has been found that the albumin excretion in urine correlates significantly to the albumin/creatinine ratio during pregnancy. The urinary albumin/creatinine ratio appears to be a good alternative to the dipstick method and to 24-h urine collections. PMID:15025425

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

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

  10. Long-term prognostic role of uric acid in patients with ST-elevation myocardial infarction and renal dysfunction.

    PubMed

    Lazzeri, Chiara; Valente, Serafina; Chiostri, Marco; Gensini, Gian Franco

    2015-11-01

    Patients with renal impairment have decreased excretion of uric acid, thus being particularly prone to having elevated serum uric acid concentrations. No data are available on the long-term prognostic role of uric acid in patients with ST-elevation myocardial infarction (STEMI) and renal dysfunction, submitted to percutaneous coronary intervention (PCI). We therefore prospectively assessed, in 329 patients with STEMI and renal dysfunction (admission estimated glomerular filtration rate <60?ml/min/1.73?m), all submitted to PCI, whether uric acid levels are associated with increased mortality at 1-year postdischarge follow-up.Patients in the third tertile of uric acid showed a higher BMI (P?=?0.014), a higher incidence of hypertension (P?=?0.029), and two or more comorbidities (P?=?0.034). The highest incidence of bleeding and of acute kidney injury was detectable in patients in the third tertile (P?=?0.011 and P?uric acid was an independent predictor of 1-year postdischarge mortality (hazard ratio 1.26, 95% confidence interval 1.06-1.51, P?=?0.011).In STEMI patients with estimated glomerular filtration rate below 60?ml/min/1.73?m treated with PCI, uric acid helps in identifying a subset of patients at a higher risk of bleeding and acute kidney injury. Increased uric acid is an independent prognostic risk factor for 1-year mortality. Further studies performed in larger cohorts of patients are needed to confirm our findings and to evaluate whether lowering uric acid in these patients is beneficial. PMID:25806469

  11. Racial/Ethnic and Gender Differences in the Relationship between Uric Acid and Metabolic Syndrome in Adolescents: An Analysis of NHANES 1999–2006

    PubMed Central

    DeBoer, Mark D.; Dong, Lili; Gurka, Matthew J.

    2011-01-01

    Background Among adolescents uric acid is associated with insulin resistance, hypertension and the metabolic syndrome (MetS) and in adults high uric acid levels are an independent risk factor for cardiovascular disease and diabetes. Objective Determine whether the relationship of uric acid with MetS varies in adolescents by race/ethnicity and gender. Methods We used linear regression to evaluate associations between uric acid and other MetS-associated clinical and laboratory measures among 3,296 non-Hispanic-white, non-Hispanic-black and Hispanic adolescents age 12–19y participating in the National Health and Nutrition Evaluation Survey (1999–2006). Results Overall, non-Hispanic-white males and females had the highest uric acid levels among the three racial/ethnic groups. In each racial/ethnic group there were higher uric acid levels for those adolescents with vs. without MetS. However, the extent of the MetS-related increase in uric acid level varied by race and gender. Among males, MetS was associated with the greatest increases in uric acid among non-Hispanic whites. However, among females, the MetS-related increase in uric acid was greatest among non-whites. Non-Hispanic-white females exhibited the lowest degrees of correlation between levels of uric acid and MetS-associated variables. Uric acid levels did not correlate with insulin levels in non-Hispanic-white females. Conclusions These data suggest the relationship between uric acid and MetS varies by race/ethnicity and gender. In particular, non-Hispanic-white males exhibit a strong relationship and non-Hispanic-white females exhibit a relatively poor correlation between uric acid and MetS-related factors. These data may have implications for the use of uric acid as a marker of future risk among adolescents. PMID:22000606

  12. Normalisation of urinary biomarkers to creatinine for clinical practice and research – when and why

    PubMed Central

    Tang, Kai Wen Aaron; Toh, Qi Chun; Teo, Boon Wee

    2015-01-01

    Acute kidney injury (AKI) and chronic kidney disease (CKD) are major health problems. Urinary biomarkers have both diagnostic and prognostic utility in AKI and CKD. However, how biomarker excretion rates should be reported, especially whether they should be normalised to urinary creatinine concentration (uCr), is controversial. Some studies suggest that normalisation to uCr may be inappropriate at times, as urinary creatinine excretion rate may vary greatly, depending on the situation. Notably, recent studies suggest that while normalisation of values to UCr may be valid for the evaluation of CKD and prediction of AKI sequelae and occurrences, it could be inappropriate for the diagnosis of AKI, or in the presence of certain acute kidney disease states. PMID:25640093

  13. ?2?Microglobulin, Cystatin C, and Creatinine and Risk of Symptomatic Peripheral Artery Disease

    PubMed Central

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

    2014-01-01

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

  14. Fluorescence-based assay for reactive oxygen species: A protective role for creatinine

    SciTech Connect

    Glazer, A.N. )

    1988-06-01

    Attack by reactive oxygen species leads to a decay in phycoerythrin fluorescence emission. This phenomenon provides a versatile new assay for small molecules and macromolecules that can function as protective compounds. With 1-2 {times} 10{sup {minus}8} M phycoerythrin, under conditions where peroxyl radical generation is rate-limiting, the fluorescence decay follows apparent zero-order kinetics. On reaction with HO{center dot}, generated with the ascorbate-Cu{sup 2+} system, the fluorescence decays with apparent first-order kinetics. Examination of the major components of human urine in this assay confirms that at physiological concentrations, urate protects against both types of oxygen radicals. A novel finding is that creatinine protects efficiently by a chelation mechanism against radical damage in the ascorbate-Cu{sup 2+} system at creatinine, ascorbate, and Cu{sup 2+} concentrations comparable to those in normal urine. Urate and creatinine provide complementary modes of protection against reactive oxygen species in the urinary tract.

  15. Detection of urinary estrogen conjugates and creatinine using near infrared spectroscopy in Bornean orangutans (Pongo Pygmaeus).

    PubMed

    Kinoshita, Kodzue; Kuze, Noko; Kobayashi, Toshio; Miyakawa, Etsuko; Narita, Hiromitsu; Inoue-Murayama, Miho; Idani, Gen'ichi; Tsenkova, Roumiana

    2016-01-01

    For promoting in situ conservation, it is important to estimate the density distribution of fertile individuals, and there is a need for developing an easy monitoring method to discriminate between physiological states. To date, physiological state has generally been determined by measuring hormone concentration using radioimmunoassay or enzyme immunoassay (EIA) methods. However, these methods have rarely been applied in situ because of the requirements for a large amount of reagent, instruments, and a radioactive isotope. In addition, the proper storage of the sample (including urine and feces) on site until analysis is difficult. On the other hand, near infrared (NIR) spectroscopy requires no reagent and enables rapid measurement. In the present study, we attempted urinary NIR spectroscopy to determine the estrogen levels of orangutans in Japanese zoos and in the Danum Valley Conservation Area, Sabah, Malaysia. Reflectance NIR spectra were obtained from urine stored using a filter paper. Filter paper is easy to use to store dried urine, even in the wild. Urinary estrogen and creatinine concentrations measured by EIA were used as the reference data of partial least square (PLS) regression of urinary NIR spectra. High accuracies (R (2) > 0.68) were obtained in both estrogen and creatinine regression models. In addition, the PLS regressions in both standards showed higher accuracies (R (2) > 0.70). Therefore, the present study demonstrates that urinary NIR spectra have the potential to estimate the estrogen and creatinine concentrations. PMID:26561334

  16. Urinary Aldosterone/Creatinine Ratio After Fludrocortisone Suppression Consistent with PHA in a Cat.

    PubMed

    Koutinas, Christos K; Soubasis, Nektarios C; Djajadiningrat-Laanen, Sylvia C; Kolia, Elissavet; Theodorou, Konstantina

    2015-01-01

    A 9 yr old cat was presented with clinical signs and laboratory abnormalities attributed to arterial hypertension (mean systolic arterial pressure, 290 mm Hg). Plasma aldosterone concentration was increased at the time of admission (651 pmol/L), but serum creatinine and potassium concentrations were within the reference range. A second increased aldosterone (879 pmol/L) and normal plasma renin activity (1.85 ng/mL/hr) resulted in an increased aldosterone/renin ratio, which was suggestive of primary hyperaldosteronism (PHA). To further support the diagnosis of PHA, the urinary aldosterone/creatinine ratio was calculated both before and after oral administration of fludrocortisone acetate (0.05 mg/kg q 12 hr for 4 consecutive days). The urinary aldosterone/creatinine ratio was 92.6 × 10(-9) before fludrocortisone administration and 155.8 × 10(-9) 4 days later. Absence of suppression was typical of PHA. The cat had a limited response to antihypertensive medication and died before treatment for PHA could be instituted. A necropsy was not permitted by the owner. PMID:26355586

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

    SciTech Connect

    Friedlander, M.A.; 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).

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  20. Interactions between Hydrophobic and Ionic Solutes in Aqueous Guanidinium Chloride and Urea Solutions: Lessons

    E-print Network

    Thirumalai, Devarajan

    Interactions between Hydrophobic and Ionic Solutes in Aqueous Guanidinium Chloride and Urea species in aqueous guanidinium chloride and urea solutions using molecular dynamics simulations. Hydrophobic association is not significantly changed in urea or guanidinium chloride solutions. The strength

  1. 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

    ...antidumping duty order on solid urea from the Soviet...Commonwealth of Independent States. See Solid Urea From the Union of...Antidumping Order on Solid Urea From the Union of...Commonwealth of Independent States and the Baltic...

  2. 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

    ...antidumping duty order on solid urea from the Soviet...Commonwealth of Independent States. See Solid Urea From the Union of...Antidumping Order on Solid Urea From the Union of...Commonwealth of Independent States and the Baltic...

  3. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...true Urea-formaldehyde resins in molded...177.1900 Food and Drugs ...Repeated Use Food Contact Surfaces...1900 Urea-formaldehyde resins in molded...articles. Urea-formaldehyde resins may be safely used as the food-contact...

  4. 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

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

    PubMed Central

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

    2015-01-01

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

  6. 76 FR 15339 - Solid Urea From Russia and Ukraine

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-21

    ... its notice of institution (75 FR 74746, December 1, 2010) were adequate and that the respondent... Solid Urea From Russia and Ukraine AGENCY: United States International Trade Commission. ACTION: Notice... on solid urea from Russia and Ukraine. SUMMARY: The Commission hereby gives notice that it...

  7. Final report of the safety assessment of Urea.

    PubMed

    2005-01-01

    Although Urea is officially described as a buffering agent, humectant, and skin-conditioning agent-humectant for use in cosmetic products, there is a report stating that Urea also is used in cosmetics for its desquamating and antimicrobial action. In 2001, the Food and Drug Administration (FDA) reported that Urea was used in 239 formulations. Concentrations of use for Urea ranged from 0.01% to 10%. Urea is generally recognized as safe by FDA for the following uses: side-seam cements for food contact; an inhibitor or stabilizer in pesticide formulations and formulations applied to animals; internal sizing for paper and paperboard and surface sizing and coating of paper and paper board that contact water-in-oil dairy emulsions, low-moisture fats and oils, moist bakery products, dry solids with surface containing no free fats or oil, and dry solids with the surface of fat or oil; and to facilitate fermentation of wine. Urea is the end product of mammalian protein metabolism and the chief nitrogenous compound of urine. Urea concentrations in muscle, liver, and fetuses of rats increased after a subcutaneous injection of Urea. Urea diffused readily through the placenta and into other maternal and fetal organs. The half-life of Urea injected into rabbits was on the order of several hours, and the reutilization rate was 32.2% to 88.8%. Urea given to rats by a bolus injection or continuous infusion resulted in distribution to the following brain regions: frontal lobe, caudate nucleus, hippocampus, thalamus plus hypothalamus, pons and white matter (corpus callosum). The permeability constant after treatment with Urea of whole skin and the dermis of rabbits was 2.37 +/- 0.13 (x 10(6)) and 1.20 +/- 0.09 (x10(3)) cm/min, respectively. The absorption of Urea across normal and abraded human skin was 9.5% +/- 2.3% and 67.9% +/- 5.6%, respectively. Urea increased the skin penetration of other compounds, including hydrocortisone. No toxicity was observed for Urea at levels as high as 2000 mg/kg in acute oral studies using female rats or mice. No signs of toxicity were observed in male piglets dosed orally with up to 4 g/kg Urea for 5 days. Dogs dosed orally with 5 to 30 g/L Urea for 4 to 10 days had signs of toxicity, including weakness, anorexia, vomiting and retching, diarrhea and a decreased body temperature, which led to a deep torpor or coma. No significant microscopic changes were observed in the skin of male nude mice dermally exposed to 100% Urea for 24 h. No observable effect on fetal development was seen in rats and mice dosed orally with an aqueous solution of Urea (2000 mg/kg) on days 10 and 12 of gestation. The mean number of implants, live fetuses, percent fetal resorptions, mean fetal weight, and percent fetuses malformed were comparable to control group. A detergent containing 15% Urea was injected into pregnant ICR-JCl mice and dams and fetuses had no significant differences when compared to control animals. Urea given orally did not enhance the developmental toxicity of N-nitrosomethylurea. Female Sprague-Dawley rats injected in the uterine horn with 0.05 ml Urea on day 3 (preimplantation) or on day 7 (post implantation) exhibited no maternal mortality or morbidity; a dose-dependent reduction in embryo survival was seen with preimplantation treatment. Urea injected intra-amniotically induces mid-trimester abortions in humans. Urea was not genotoxic in several bacterial and mammalian assays; although in assays where Urea was used at a high concentration, genotoxicity was found, many in in vitro assays. Urea is commonly used in studies of DNA because it causes uncoiling of DNA molecules. Urea was not carcinogenic in Fisher 344 rats or C57B1/6 mice fed diets containing up to 4.5% Urea. Exposure of normal human skin to 60% Urea produced no significant irritation in one study, but 5% Urea was slightly irritating and 20% Urea was irritating in other reports. Burning sensations are the most frequently reported effect of Urea used alone or with other agents in treatment of diseased skin. Overall, there are few reports of sensiti

  8. 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...

  9. [The frequency of gout and other disorders of uric acid metabolism in Dalmatia in comparison with these disorders in Croatia].

    PubMed

    Klarica, J; Jaji?, I

    1993-01-01

    According to the literature gout is more frequent in Dalmatia than in continental part of Croatia. Higher average values of uric acid in serum, prevalence of hyperuicaemia as well as uric nephrolithiasis are also seen more frequently in Dalmatia comparing to the continental Croatia. This is probably genetically determined and is connected with metabolic changes of uric acid. Relative isolation of population in Dalmatian where the part of immigrants from other regions since the war started was very small favoured these changes. In addition some exogenous factors contribute in clinical manifestation of uric acid metabolic disturbances. The most important among them are consumption of food rich in nucleoproteins and dehydration in summer period. PMID:7761704

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

    E-print Network

    Gaucher, Eric

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

  11. Urea enhances the photodynamic efficiency of methylene blue.

    PubMed

    Nuńez, Silvia C; Yoshimura, Tania M; Ribeiro, Martha S; Junqueira, Helena C; Maciel, Cleiton; Coutinho-Neto, Maurício D; Baptista, Maurício S

    2015-09-01

    Methylene blue (MB) is a well-known photosensitizer used mostly for antimicrobial photodynamic therapy (APDT). MB tends to aggregate, interfering negatively with its singlet oxygen generation, because MB aggregates lean towards electron transfer reactions, instead of energy transfer with oxygen. In order to avoid MB aggregation we tested the effect of urea, which destabilizes solute-solute interactions. The antimicrobial efficiency of MB (30 ?M) either in water or in 2M aqueous urea solution was tested against a fungus (Candida albicans). Samples were kept in the dark and irradiation was performed with a light emitting diode (? = 645 nm). Without urea, 9 min of irradiation was needed to achieve complete microbial eradication. In urea solution, complete eradication was obtained with 6 min illumination (light energy of 14.4 J). The higher efficiency of MB/urea solution was correlated with a smaller concentration of dimers, even in the presence of the microorganisms. Monomer to dimer concentration ratios were extracted from the absorption spectra of MB solutions measured as a function of MB concentration at different temperatures and at different concentrations of sodium chloride and urea. Dimerization equilibrium decreased by 3 and 6 times in 1 and 2M urea, respectively, and increased by a factor of 6 in 1M sodium chloride. The destabilization of aggregates by urea seems to be applied to other photosensitizers, since urea also destabilized aggregation of Meso-tetra(4-n-methyl-pyridyl)porphyrin, which is a positively charged porphyrin. We showed that urea destabilizes MB aggregates mainly by causing a decrease in the enthalpic gain of dimerization, which was exactly the opposite of the effect of sodium chloride. In order to understand this phenomenon at the molecular level, we computed the free energy for the dimer association process (?G(dimer)) in aqueous solution as well as its enthalpic component in aqueous and in aqueous/urea solutions by molecular dynamics simulations. In 2M-urea solution the atomistic picture revealed a preferential solvation of MB by urea compared with MB dimers while changes in ?H(dimer) values demonstrated a clear shift favoring MB monomers. Therefore, MB monomers are more stable in urea solutions, which have significantly better photophysics and higher antimicrobial activity. This information can be of use for dental and medical professionals that are using MB based APDT protocols. PMID:25862463

  12. Structure and permeation mechanism of a mammalian urea transporter

    SciTech Connect

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

    2012-09-17

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

  13. Regeneration of hemofiltrate by anodic oxidation of urea.

    PubMed

    Köster, K; Wendt, H; Gallus, J; Krisam, G; Lehmann, H D

    1983-05-01

    Urea can be oxidized electrochemically in a chloride solution to carbon dioxide, water, and nitrogen. The microkinetics of this hypochlorite-mediated urea oxidation are elucidated. Based on this kinetic information, the optimal conditions and construction principles for an electrochemical reactor are deduced. The construction of a cheap, disposable oxidation cell and necessary auxiliary equipment are described. In vitro data are reported for urea removal. A 36-L volume was used to simulate a 60-kg patient; 18 L was recirculated through a 0.12-m2 oxidation cell. Within 3 h, 35 g urea could be removed from the system. The technical and economic possibilities as well as safety requirements for hemofiltrate regeneration to a reinfusable substitution solution by anodic urea oxidation are discussed critically. Although the process does not appear to be economically practical for discontinuous hemofiltration, it might be desirable for continuous (24 h/day) treatment. PMID:6307234

  14. 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

  15. Quantum crystallographic charge density of urea

    E-print Network

    Wall, Michael E

    2015-01-01

    Standard X-ray crystallography methods use free-atom models to calculate total charge densities. Real molecules, however, have shared charge that is not captured accurately using free-atom models. To address this limitation, a charge density model of crystalline urea was calculated using high-level quantum theory and refined against publicly available ultra high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared to models obtained using atomic monopole or multipole methods. Despite using only the same number of free parameters as the monopole model, the agreement of the quantum model with the data is comparable to the multipole model. The monopole and multipole charge densities are more similar to each other than they are to the quantum charge density, indicating the quantum model provides substantially new information. In particular, the quantum model is smoother away from the atom centers and lacks peaks betw...

  16. An Amperometric Biosensor for Uric Acid Determination Prepared From Uricase Immobilized in Polyaniline-Polypyrrole Film

    PubMed Central

    Arslan, Fatma

    2008-01-01

    A new amperometric uric acid biosensor was developed by immobilizing uricase by a glutaraldehyde crosslinking procedure on polyaniline-polypyrrole (pani-ppy) composite film on the surface of a platinum electrode. Determination of uric acid was performed by the oxidation of enzymatically generated H2O2 at 0.4 V vs. Ag/AgCl. The linear working range of the biosensor was 2.5×10-6 × 8.5×10-5 M and the response time was about 70 s. The effects of pH, temperature were investigated and optimum parameters were found to be 9.0, 55 °C, respectively. The stability and reproducibility of the enzyme electrode have been also studied.

  17. 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

  18. Synthesis of aluminum nitride nanoparticles by a facile urea glass route and influence of urea/metal molar ratio

    NASA Astrophysics Data System (ADS)

    Gao, Zhifang; Wan, Yizao; Xiong, Guangyao; Guo, Ruisong; Luo, Honglin

    2013-09-01

    Attention toward nanosized aluminum nitride (AlN) was rapidly increasing due to its physical and chemical characteristics. In this work, nanocrystalline AlN particles were prepared via a simple urea glass route. The effect of the urea/metal molar ratio on the crystal structure and morphology of nanocrystalline AlN particles was studied using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results revealed that the morphology and the crystal structure of AlN nanoparticles could be controlled by adjusting the urea/metal ratio. Furthermore, a mixture of Al2O3 and h-AlN was detected at the urea/metal molar ratio of 4 due to the inadequate urea content. With increasing the molar ratio, the pure h-AlN was obtained. In addition, the nucleation and growth mechanisms of AlN nanocrystalline were proposed.

  19. Variation in the uric acid transporter gene (SLC2A9) and memory performance.

    PubMed

    Houlihan, Lorna M; Wyatt, Niki D; Harris, Sarah E; Hayward, Caroline; Gow, Alan J; Marioni, Riccardo E; Strachan, Mark W J; Price, Jackie F; Starr, John M; Wright, Alan F; Deary, Ian J

    2010-06-01

    Understanding human cognitive ageing is important to improve the health of an increasing elderly population. Serum uric acid levels have been linked to many ageing illnesses and are also linked to cognitive functioning, though the direction of the association is equivocal. SLC2A9, a urate transporter, influences uric acid levels. This study first tested four SLC2A9 SNPs, previously associated with uric acid levels, in approximately 1000 Scots: the Lothian Birth Cohort 1936 (LBC1936). These participants were tested on general cognitive ability at ages 11 and 70. At age 70, they took a battery of diverse cognitive tests. Two replication cohorts were investigated. First, the LBC1921, who were tested on general cognitive ability at age 11. At ages 79 (n = 520), 83 (n = 281) and age 87 (n = 177), they completed cognitive ability test batteries. Second, the Edinburgh Type 2 Diabetes Study (ET2DS) were tested for cognitive abilities aged between 60 and 75 years (n = 1066). All analyses were adjusted for age, gender, body mass index and either childhood cognitive ability test score (LBC) or vocabulary-a measure of prior cognitive ability in ET2DS. Significant associations were detected with SLC2A9 and a general memory factor in LBC1936 and other individual cognitive ability tests (lowest P = 0.0002). The association with logical memory replicated in LBC1921 at all ages (all P < 0.05). These associations were not replicated in ET2DS (all P > 0.1). If the positive associations withstand, then this study could suggest that higher uric acid levels may be associated with increased performance on memory-related tasks. PMID:20197412

  20. Uric Acid Induces Trophoblast Il-1? Production Via The Inflammasome: Implications For The Pathogenesis Of Preeclampsia

    PubMed Central

    Mulla, Melissa J.; Myrtolli, Kledia; Potter, Julie; Boeras, Crina; Kavathas, Paula B.; Sfakianaki, Anna K.; Tadesse, Serkelem; Norwitz, Errol R.; Guller, Seth; Abrahams, Vikki M.

    2010-01-01

    Problem Preeclampsia is associated with hyperuricemia, which correlates with the disease severity. Levels of circulating uric acid increase before the clinical manifestations, suggesting they may be causally related. Uric acid, or monosodium urate (MSU), activates the Nod-like receptor, Nalp3, leading to inflammasome activation and IL-1? processing. Since preeclampsia is associated with placental immune/inflammatory dysregulation, we sought to determine in the trophoblast, the presence of the Nalp3 inflammasome, and the effect of MSU on its activation. Method of Study Isolated first and third trimester trophoblast were assessed for expression of the inflammasome components, Nalp1, Nalp3 and ASC. First trimester trophoblast cells were incubated with or without MSU, after which, IL-1? secretion and processing and caspase-1 activation was determined. Results Trophoblast cells expressed Nalp1, Nalp3 and ASC under basal conditions. Following incubation with MSU, first trimester trophoblast IL-1? secretion was upregulated. This correlated with increased expression levels of active IL-1? and active caspase-1. ASC knockdown reduced MSU-induced IL-1? secretion. Conclusion These findings demonstrate that uric acid activates the inflammasome in the trophoblast, leading to IL-1? production. This may provide a novel mechanism for the induction of inflammation at the maternal-fetal interface leading to placental dysfunction and adverse pregnancy outcome, including preeclampsia. PMID:21352397

  1. Do Uric Acid Deposits in Zooxanthellae Function as Eye-Spots?

    PubMed Central

    Yamashita, Hiroshi; Kobiyama, Atsushi; Koike, Kazuhiko

    2009-01-01

    The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium) and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100–150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot. PMID:19609449

  2. 3-D periodic mesoporous nickel oxide for nonenzymatic uric acid sensors with improved sensitivity

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Cao, Yang; Chen, Yong; Zhou, Yang; Huang, Qingyou

    2015-12-01

    3-D periodic mesoporous nickel oxide (NiO) particles with crystalline walls have been synthesized through the microwave-assisted hard template route toward the KIT-6 silica. It was investigated as a nonenzymatic amperometric sensor for the detection of uric acid. 3-D periodic nickel oxide matrix has been obtained by the hard template route from the KIT-6 silica template. The crystalline nickel oxide belonged to the Ia3d space group, and its structure was characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and transmission electron microscopy (TEM). The analysis results showed that the microwave-assisted mesoporous NiO materials were more appropriate to be electrochemical sensors than the traditional mesoporous NiO. Cyclic voltammetry (CV) revealed that 3-D periodic NiO exhibited a direct electrocatalytic activity for the oxidation of uric acid in sodium hydroxide solution. The enzyme-less amperometric sensor used in the detection of uric acid with detection limit of 0.005 ?M (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 ?A mM-1 cm-2, and a possible mechanism was also given in the paper.

  3. D-tagatose, a stereoisomer of D-fructose, increases blood uric acid concentration.

    PubMed

    Buemann, B; Toubro, S; Holst, J J; Rehfeld, J F; Bibby, B M; Astrup, A

    2000-08-01

    D-Fructose has been found to increase uric acid production by accelerating the degradation of purine nucleotides, probably due to hepatocellular depletion of inorganic phosphate (Pi) by an accumulation of ketohexose-1-phosphate. The hyperuricemic effect of D-tagatose, a stereoisomer of D-fructose, may be greater than that of D-fructose, as the subsequent degradation of D-tagatose-1-phosphate is slower than the degradation of D-fructose-1-phosphate. We tested the effect of 30 g oral D-tagatose versus D-fructose on plasma uric acid and other metabolic parameters in 8 male subjects by a double-blind crossover design. Both the peak concentration and 4-hour area under the curve (AUC) of serum uric acid were significantly higher after D-tagatose compared with either 30 g D-fructose or plain water. The decline in serum Pi concentration was greater at 50 minutes after D-tagatose versus D-fructose. The thermogenic and lactacidemic responses to D-tagatose were blunted compared with D-fructose. D-Tagatose attenuated the glycemic and insulinemic responses to a meal that was consumed 255 minutes after its administration. Moreover, both fructose and D-tagatose increased plasma concentrations of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1). The metabolic effects of D-tagatose occurred despite its putative poor absorption. PMID:10954012

  4. A simple and rapid creatinine sensing via DLS selectivity, using calix[4]arene thiol functionalized gold nanoparticles.

    PubMed

    Sutariya, Pinkesh G; Pandya, Alok; Lodha, Anand; Menon, Shobhana K

    2016-01-15

    A new, simple, ultra-sensitive and selective approach has been reported for the "on spot" colorimetric detection of creatinine based on calix[4]arene functionalized gold nanoparticles (AuNPs) with excellent discrimination in the presence of other biomolecules. The lower detection limit of the method is 2.16nM. The gold nanoparticles and p-tert-butylcalix[4]arene were synthesized by microwave assisted method. Specifically, in our study, we used dynamic light scattering (DLS) which is a powerful method for the determination of small changes in particle size, improved selectivity and sensitivity of the creatinine detection system over colorimetric method. The nanoassembly is characterized by Transmission electron microscopy (TEM), DLS, UV-vis and ESI-MS spectroscopy, which demonstrates the binding affinity due its ability of hydrogen bonding and electrostatic interaction between -NH group of creatinine and pSDSC4. It exhibits fast response time (<60s) to creatinine and has long shelf-life (>5 weeks). The developed pSDSC4-AuNPs based creatinine biosensor will be established as simple, reliable and accurate tool for the determination of creatinine in human urine samples. PMID:26592650

  5. Tri-enzyme functionalized ZnO-NPs/CHIT/c-MWCNT/PANI composite film for amperometric determination of creatinine.

    PubMed

    Yadav, Sandeep; Devi, Rooma; Kumar, Ashok; Pundir, C S

    2011-10-15

    A new zinc oxide nanoparticles/chitosan/carboxylated multiwall carbonnanotube/polyaniline (ZnO-NPs/CHIT/c-MWCNT/PANI) composite film has been synthesized on platinum (Pt) electrode using electrochemical techniques. Three enzymes, creatinine amidohydrolase (CA), creatine amidinohydrolase (CI) and sarcosine oxidase (SO) were immobilized on ZnO-NPs/CHIT/c-MWCNT/PANI/Pt electrode to construct the creatinine biosensor. The enzyme electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS). The enzyme electrode detects creatinine level as low as 0.5 ?M at a signal to noise ratio of 3 within 10s at pH 7.5 and 30°C. The fabricated creatinine biosensor showed linear working range of 10-650 ?M creatinine with a sensitivity of 0.030 ?A ?M(-1)cm(-2). The biosensor shows only 15% loss of its initial response over a period of 120 days when stored at 4°C. The fabricated biosensor was successfully employed for determination of creatinine in human blood serum. PMID:21803561

  6. Determination of the serum levels of troponin I and creatinine among Sudanese type 2 diabetes mellitus patients

    PubMed Central

    Karar, Tarig; Elfaki, Elyasa Mustafa; Qureshi, Shoeb

    2015-01-01

    Background: Diabetes mellitus (DM) is a significant risk factor for developing cardiac diseases. Hence, we compare the serum levels of cardiac troponin I (CTnI) among type 2 diabetic and healthy patients. We additionally correlated CTnI and creatinine levels with duration of disease. Materials and Methods: A cross-sectional study was conducted at Department of Clinical Chemistry, Sudan University of Sciences and Technology, Khartoum, Sudan, from February 2008 to February 2011. 200 patients diagnosed with DM type 2 from Jabir Abulizz Diabetes Centre in Khartoum state, Sudan, and 100 healthy volunteers were included in this study. Blood samples were collected from both groups, and the serum levels of CTnI, creatinine, fasting plasma glucose and glycosylated hemoglobin (HbA1c) levels were measured. Results: Significant increase in serum levels of CTnI, glucose, HbA1c, and creatinine was observed in diabetic patients compared to healthy controls. In addition, the significant increase in CTnI and creatinine levels was observed among diabetic patients with ischemic heart disease or hypertension when compared with those without ischemic heart disease or hypertension. Further a strong positive correlation was observed between the duration of diabetes and the serum levels of CTnI and creatinine (r = 0.84, P > 0.01) and (r = 0.72, P > 0.01), respectively. Conclusion: The higher levels of CTnI and creatinine may be indicative of progressive cardiovascular disease and nephropathy among diabetic patients. PMID:26604626

  7. Estimation of Glomerular Filtration Rate Based on Serum Cystatin C versus Creatinine in a Uruguayan Population

    PubMed Central

    Lujambio, Inés; Sottolano, Mariana; Robaina, Sebastián; Carusso, Florencia; da Rosa, Alicia; Ríos, Ana Carina; Olascoaga, Alicia; Gadola, Liliana; Noboa, Oscar; Staessen, Jan A.; Boggia, José

    2014-01-01

    Background. Estimation of glomerular filtration rate (eGFR) from biomarkers has evolved and multiple equations are available to estimate renal function at bedside. Methods. In a random sample of 119 Uruguayans (54.5% women; 56.2 years (mean)), we used Bland and Altman's method and Cohen's kappa statistic to assess concordance on a continuous or categorical (eGFR < 60 versus ?60?mL/min/1.73?m2) scale between eGFRcys (reference) and eGFR derived from serum creatinine according to the Modification of Diet in Renal Disease (eGFRmdrd) or the Chronic Kidney Disease Epidemiology Collaboration equations (eGFRepi) or from both serum cystatin C and creatinine (eGFRmix). Results. In all participants, eGFRmdrd, eGFRepi, and eGFRmix were, respectively, 9.7, 11.5, and 5.6?mL/min/1.73?m2 higher (P < 0.0001) than eGFRcys. The prevalence of eGFR <60?mL/min/1.73?m2 was the highest for eGFRcys (21.8%), intermediate for eGFRmix (11.8%), and the lowest for eGFRmdrd (5.9%) and eGFRepi (3.4%). Using eGFRcys as reference, we found only fair agreement with the equations based on creatinine (Cohen's kappa statistic 0.15 to 0.23). Conclusion. Using different equations we reached clinically significant differences in the estimation of renal function. eGFRcys provides lower estimates, resulting in higher prevalence of eGFR <60?mL/min/1.73?m2. PMID:25215234

  8. Urea production and salvage during pregnancy in normal Jamaican women.

    PubMed

    Forrester, T; Badaloo, A V; Persaud, C; Jackson, A A

    1994-09-01

    The pattern of aggregate nitrogen demand during pregnancy and the fetal and maternal components are unclear. Excess demand enhances efficiency of nitrogen utilization. Urea salvage contributes to enhanced efficiency. Dietary protein intake, urea production, and salvage of urea nitrogen were measured in eight nonpregnant control subjects, and trimesterly in nine pregnant women. Production was measured after prime-intermittent intravenous doses of [15N 15N]-urea by dilution of label in urinary urea. Dietary protein intake was greater in trimester 1 than in nonpregnant women (167 +/- 36 vs 224 +/- 60 mg N.kg-1.d-1), and increased further in trimester 2 (266 +/- 59 mg N.kg-1.d-1). Urea production was not higher during pregnancy. Despite higher protein intake, urea salvage was higher in pregnancy (40 +/- 24 nonpregnant vs 77 +/- 23, 61 +/- 31, and 51 +/- 12 mg N.kg-1.d-1). Therefore, the demand-supply gap for nitrogen was greatest early in pregnancy when fetoplacental growth is slowest, and implies heightened maternal demand. PMID:8074063

  9. Kinetic study on urea uptake with chitosan based sorbent materials.

    PubMed

    Xue, Chen; Wilson, Lee D

    2016-01-01

    A one-pot kinetic uptake study of urea in aqueous solution with various chitosan sorbent materials such as pristine chitosan, cross-linked chitosan with glutaraldehyde from low (C-1) to higher (C-2) glutaraldehyde content, and a Cu(II) complex of a glutaraldehyde cross-linked chitosan material (C-3) is reported herein. The kinetic uptake profiles were analyzed by the pseudo-first order (PFO) and pseudo-second-order (PSO) models, respectively. The uptake rate constant of urea and the sorption capacity (qe) of high molecular weight (HMW) chitosan, C-1, C-2, and C-3 were best described by the PFO model. The uptake rate constant of urea with the various sorbents is listed in ascending order: HMW chitosanurea/g sorbent) for the sorbent/urea systems are listed in ascending order: HMW chitosan (48.1)?C-1 (44.7)urea uptake and greater adsorption capacity when compared with pristine chitosan. The observed trends are in agreement with the greater surface accessibility and pore structure properties of cross-linked chitosan based on scanning electron microscopy studies. These results further illustrate the rational design of chitosan-based materials for the controlled uptake of urea in aquatic environments. PMID:26453866

  10. Urea encapsulation in modified starch matrix for nutrients retention

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  11. Discovery of URAT1 SNPs and association between serum uric acid levels and URAT1

    PubMed Central

    Cho, Sung Kweon; Kim, Soriul; Chung, Jae-Yong; Jee, Sun Ha

    2015-01-01

    Objectives Human urate transporter 1 (URAT1) is a member of the organic anion transporter family (SLC22A12) that primarily regulates the renal tubular reabsorption of uric acid. This case–control study was designed to analyse whether hURAT1 might also be a candidate gene for hyperuricaemia or hypouricaemia. Setting We recruited 68 healthy volunteers and divided them into two groups: a normal uric acid group and a hyperuricaemia group. We analysed the sequence of the URAT1 gene and found five significant single nucleotide polymorphisms (SNPs). We then selected 900 male subjects from the 262?200 enrolled in the Korean Cancer Prevention Study-II (KCPS-II) cohort for further genetic analysis. Participants DNA samples from 36 individuals with normal uric acid (<4.5?mg/dL) and 32 individuals with hyperuricaemia (>8.5?mg/dL) were sequenced. Five significant SNPs (rs7929627, rs75786299, rs3825017, rs11602903 and rs121907892) were identified. We then chose 900 subjects from the KCPS-II cohort consisting of 450 subjects with normal uric acid (UA <4.1?mg/dL) and 450 subjects with hyperuricaemia (UA >8.7?mg/dL). The groups were matched by age, body mass index, metabolic syndrome and use of anti-hypertensive medication. Primary outcome measures We compared the OR of the incidence of hyperuricaemia by URAT1 genotype. Results The strongest association with hyperuricaemia was observed for rs75786299 (IVS3+11A/G) with an OR of 32.05. rs7929627 (IVS7-103A/G) and rs3825017 (N82N) showed an association with hyperuricaemia with ORs of 2.56 and 2.29, respectively. rs11602903 (788A/T) and rs121907892 (W258X) were negatively correlated with hyperuricaemia with ORs of 0.350 and 0.447, respectively. Individuals carrying the GATAG haplotype (n=32)—a relatively common variant consisting of rs7929627, rs75786299 and rs3825017—showed the highest risk for hyperuricaemia with an OR of 92.23 (p=9.55×10?3). Conclusions These results indicate that five newly described SNPs in the hURAT1 gene are significantly associated with uric acid level (4-2008-0318 and 4-2011-0277). PMID:26603249

  12. 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.

  13. 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

    ...solid urea from the Russian Federation (Russia). The period of review is July 1, 2010...antidumping duty order on solid urea from Russia. See Solid Urea From the Russian Federation...notice for all shipments of solid urea from Russia entered, or withdrawn from...

  14. 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...

  15. Performance of the estimated glomerular filtration rate creatinine and cystatin C based equations in Thai patients with chronic glomerulonephritis

    PubMed Central

    Satirapoj, Bancha; Jirawatsiwaporn, Ketkan; Tangwonglert, Theerasak; Choovichian, Panbubpa

    2015-01-01

    Background Glomerular filtration rate (GFR) is considered the indicator of overall kidney function, and therefore, its assessment has become an important clinical tool in the daily care of chronic glomerulonephritis (CGN) patients. Currently, practical guidelines recommend using Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations to assess GFR in CKD patients. Methods A cross-sectional study was performed in CGN patients. Standard GFR was measured using 24-hour urine creatinine clearance. GFR was estimated using the Cockcroft-Gault, Modification of Diet in Renal Disease, CKD-EPI equation based creatinine, cystatin C, and combined creatinine and cystatin C. The performance of GFR estimation equations were examined using bias, precision and accuracy and agreement between standard GFR and estimated GFR by calculating Cohen’s k. Results A total of 125 patients (74 male, 59.2%) with mean age 56.1±18.1 years were included. Mean standard GFR was 51.6±32.2 mL/min per 1.73 m2. A significant correlation was found between standard GFR and all estimated GFRs (r=0.573 to 0.660, P<0.001). CKD-EPI-creatinine-cystatin C equation had the smallest absolute bias and the significantly highest accuracy, although it was not significantly different from CKD-EPI-cystatin C equation (P=0.523). CKD-EPI-creatinine-cystatin C equation had the highest accuracy to classify CKD staging (Cohen’s k=0.345), but it underestimated GFR in 32% and overestimated GFR in 18% of the CGN patients. Conclusion CKD-EPI-creatinine-cystatin C equation estimated GFR with little bias, and the highest accuracy among CGN patients. This equation gave a better estimate of GFR than the equation based on serum creatinine. PMID:26527894

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

    NASA Technical Reports Server (NTRS)

    Geiger, P. J.

    1969-01-01

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

  17. 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....

  18. IRIS TOXICOLOGICAL REVIEW OF UREA (EXTERNAL REVIEW DRAFT)

    EPA Science Inventory

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

  19. Hydrolyzable polyureas bearing hindered urea bonds.

    PubMed

    Ying, Hanze; Cheng, Jianjun

    2014-12-10

    Hydrolyzable polymers are widely used materials that have found numerous applications in biomedical, agricultural, plastic, and packaging industrials. They usually contain ester and other hydrolyzable bonds, such as anhydride, acetal, ketal, or imine, in their backbone structures. Here, we report the first design of hydrolyzable polyureas bearing dynamic hindered urea bonds (HUBs) that can reversibly dissociate to bulky amines and isocyanates, the latter of which can be further hydrolyzed by water, driving the equilibrium to facilitate the degradation of polyureas. Polyureas bearing 1-tert-butyl-1-ethylurea bonds that show high dynamicity (high bond dissociation rate), in the form of either linear polymers or cross-linked gels, can be completely degraded by water under mild conditions. Given the simplicity and low cost for the production of polyureas by simply mixing multifunctional bulky amines and isocyanates, the versatility of the structures, and the tunability of the degradation profiles of HUB-bearing polyureas, these materials are potentially of very broad applications. PMID:25406025

  20. Hydrolyzable Polyureas Bearing Hindered Urea Bonds

    PubMed Central

    2015-01-01

    Hydrolyzable polymers are widely used materials that have found numerous applications in biomedical, agricultural, plastic, and packaging industrials. They usually contain ester and other hydrolyzable bonds, such as anhydride, acetal, ketal, or imine, in their backbone structures. Here, we report the first design of hydrolyzable polyureas bearing dynamic hindered urea bonds (HUBs) that can reversibly dissociate to bulky amines and isocyanates, the latter of which can be further hydrolyzed by water, driving the equilibrium to facilitate the degradation of polyureas. Polyureas bearing 1-tert-butyl-1-ethylurea bonds that show high dynamicity (high bond dissociation rate), in the form of either linear polymers or cross-linked gels, can be completely degraded by water under mild conditions. Given the simplicity and low cost for the production of polyureas by simply mixing multifunctional bulky amines and isocyanates, the versatility of the structures, and the tunability of the degradation profiles of HUB-bearing polyureas, these materials are potentially of very broad applications. PMID:25406025

  1. Ammonia volatilization and nitrogen retention: how deep to incorporate urea?

    PubMed

    Rochette, Philippe; Angers, Denis A; Chantigny, Martin H; Gasser, Marc-Olivier; MacDonald, J Douglas; Pelster, David E; Bertrand, Normand

    2013-11-01

    Incorporation of urea decreases ammonia (NH) volatilization, but field measurements are needed to better quantify the impact of placement depth. In this study, we measured the volatilization losses after banding of urea at depths of 0, 2.5, 5, 7.5, and 10 cm in a slightly acidic (pH 6) silt loam soil using wind tunnels. Mineral nitrogen (N) concentration and pH were measured in the top 2 cm of soil to determine the extent of urea N migration and the influence of placement depth on the availability of ammoniacal N for volatilization near the soil surface. Ammonia volatilization losses were 50% of applied N when urea was banded at the surface, and incorporation of the band decreased emissions by an average of 7% cm (14% cm when expressed as a percentage of losses after surface banding). Incorporating urea at depths >7.5 cm therefore resulted in negligible NH emissions and maximum N retention. Cumulative losses increased exponentially with increasing maximum NH-N and pH values measured in the surface soil during the experiment. However, temporal variations in these soil properties were poorly related to the temporal variations in NH emission rates, likely as a result of interactions with other factors (e.g., water content and NH-N adsorption) on, and fixation by, soil particles. Laboratory and field volatilization data from the literature were summarized and used to determine a relationship between NH losses and depth of urea incorporation. When emissions were expressed as a percentage of losses for a surface application, the mean reduction after urea incorporation was approximately 12.5% cm. Although we agree that the efficiency of urea incorporation to reduce NH losses varies depending on several soil properties, management practices, and climatic conditions, we propose that this value represents an estimate of the mean impact of incorporation depth that could be used when site-specific information is unavailable. PMID:25602404

  2. Identification of allantoin, uric acid, and indoxyl sulfate as biochemical indicators of filth in food packaging by LC.

    PubMed

    Carlson, M; Thompson, R D

    2001-01-01

    A liquid chromatographic (LC) method was developed for the determination of allantoin, uric acid, and indoxyl sulfate in mammalian urine contaminated packaging material including paper bagging, corrugated cardboard, grayboard, and burlap bagging. The procedure involves solvent extraction and isolation of the 3 analytes by reversed-phase LC with ultraviolet detection at 225 nm for allantoin and 286 nm for uric acid and indoxyl sulfate. The composition of authentic mammalian urine such as mouse, rat, cat, dog, and human were also determined with regard to the 3 compounds of interest. A linear concentration range of 0.11-20.4, 0.02-10.0, and 0.04-30.0 microg/mL was obtained for allantoin, uric acid, and indoxyl sulfate, respectively. Limits of detection (LOD) and quantitation (LOQ) were 0.0104 and 0.0345 microg/mL for allantoin; 0.0018 and 0.0060 microg/mL for uric acid; and 0.0049 and 0.0165 microg/mL for indoxyl sulfate, respectively. Interday relative standard deviation values for a mixture of standard allantoin, uric acid, and indoxyl sulfate (n = 5) were 0.97, 0.80, and 0.94%, respectively. Analyte composition for 5 types of authentic mammalian urine varied from 0.19-6.88 mg/mL allantoin; 0.08-0.57 mg/mL uric acid; and 0.03-0.78 mg/mL indoxyl sulfate. Analyte content for 8 samples including 2 samples each for paper, cardboard, grayboard, and burlap bagging each contaminated with mouse or rat urine ranged from uric acid; and 17.5 to 616 microg/gm indoxyl sulfate. Recoveries of allantoin, uric acid, and indoxyl sulfate from 11 fortified samples (4 types) for both mouse and rat urine ranged from 28.2 to 114.1 % for allantoin; 32.6 to 123.4% for uric acid; and 52.6 to 118.2% for indoxyl sulfate. PMID:11417643

  3. Formation and Characteristics of Acrylonitrile/Urea Inclusion Compound

    NASA Astrophysics Data System (ADS)

    Zou, Jun-ting; Wang, Yu-song; Pang, Wen-min; Shi, Lei; Lu, Fei

    The formation process and composition of the acrylonitrile/urea inclusion compounds (AN/UIC) with different aging times and AN/urea molar feed ratios are studied by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). It is suggested that DSC could be one of the helpful methods to determine the guest/host ratio and the heat of decomposition. Meanwhile, the guest/host ratio and heat of deformation are obtained, which are 1.17 and 5361.53 J/mol, respectively. It is suggested AN molecules included in urea canal lattice may be packed flat against each other. It is found that the formation of AN/UIC depends on the aging time. XRD results reveal that once AN molecules enter urea lattice, AN/UIC are formed, which possess the final structure. When AN molecules are sufficient, the length of AN molecular arrays in urea canals increases as aging time prolonging until urea tunnels are saturated by AN.

  4. Molecular Complexation and Phase Diagrams of Urea/PEG Mixtures

    NASA Astrophysics Data System (ADS)

    Fu, Guoepeng; Kyu, Thein

    2014-03-01

    Polyethylene glycol (PEG) and urea complexation has been known to form a stable crystal due to molecular complexation. The effect of molecular weight of PEG on the phase diagrams of its blends with urea has been explored. In the case of high molecular weight PEG8k/urea, the observed phase diagram is azeotrope, accompanied by eutectoid reactions in the submerged phases such as induced stable ``alpha'' phase crystals and metastable ``beta'' phase crystals. The metastable crystal can transform to stable crystal under a certain thermal annealing condition. However, the phase diagram of PEG1k/urea is of coexistence loop, whereas PEG400/urea exhibits eutectic character. Subsequently, the change of azeotrope to eutectic behavior with PEG molecular weight is analyzed in the context of the combined Flory-Huggins theory of liquid-liquid demixing and phase field theory of crystal solidification. Of particular interest is that only a very small urea amount (2 wt%) is needed to form a stable inclusion crystal via complexation with PEG. Potential application in lithium battery is discussed based on AC impedance spectroscopy and cyclic voltammetry. Supported by NSF-DMR 1161070.

  5. Renal clearance of uric acid is linked to insulin resistance and lower excretion of sodium in gout patients.

    PubMed

    Perez-Ruiz, Fernando; Aniel-Quiroga, Maria Angeles; Herrero-Beites, Ana María; Chinchilla, Sandra Pamela; Erauskin, Gorka Garcia; Merriman, Toni

    2015-09-01

    Inefficient renal excretion of uric acid is the main pathophysiological mechanism for hyperuricemia in gout patients. Polymorphisms of renal tubular transporters linked with sodium and monosaccharide transport have yet to be demonstrated. We intended to evaluate the impact of insulin resistance, evaluated with the homeostasis model assessment (HOMA), through a transversal study of non-diabetic patients with gout, with normal renal function, not treated with any medication but colchicine as prophylaxis. One hundred and thirty-three patients were evaluated. Clearance of uric acid was inversely correlated with insulin resistance and directly correlated with fractional excretion of sodium. In multivariate analysis, hypertension and hyperlipidemia, in addition to insulin resistance and fractional excretion of sodium, were associated with renal clearance of uric acid. HOMA cutoff for efficient versus inefficient renal handling of uric acid was 2.72, close to that observed in studies of reference population. The impact of insulin resistance and renal handling of sodium on renal clearance of uric acid may help to explain why hyperuricemia is more commonly associated with diabetes and hypertension. PMID:25763991

  6. Fast vaporization solid phase microextraction and ion mobility spectrometry: A new approach for determination of creatinine in biological fluids.

    PubMed

    Jafari, Mostafa; Ebrahimzadeh, Homeira; Banitaba, Mohamma Hossein

    2015-11-01

    In this work a rapid and simple method for creatinine determination in urine and plasma samples based on aqueous derivatization of creatinine and complete vaporization of sample (as low as 10µL), followed by ion mobility spectrometry analysis has been proposed. The effect of four important parameters (extraction temperature, total volume of solution, desorption temperature and extraction time) on ion mobility signal has been studied. Under the optimized conditions, the quantitative response of ion mobility spectrometry for creatinine was linear in the range of 0-500mgL(-1) with a detection limit of 0.6mgL(-1) in urine and 0-250mgL(-1) with a detection limit of 2.6mgL(-1) in plasma sample. The limit of quantitation of creatinine was 2.1mgL(-1) and 8.7mgL(-1) in urine and plasma samples, respectively. The relative standard deviation of the method was found to be 13%. The method was successfully applied to the analysis of creatinine in biological samples, showing recoveries from 92% to 104% in urine and 101-110% in plasma samples. PMID:26452850

  7. Serum Creatinine Levels During and After Long-term Treatment with Cyclosporine A in Patients with Severe Atopic Dermatitis.

    PubMed

    van der Schaft, Jorien; van Zuilen, Arjan D; Deinum, Joukje; Bruijnzeel-Koomen, Carla A F M; de Bruin-Weller, Marjolein S

    2015-11-01

    Safety data with respect to kidney function during long-term treatment with cyclosporine A (CsA) in patients with atopic dermatitis is limited. Data on serum creatinine levels before, during and after CsA treatment were collected in a retrospective cohort of adult patients with atopic dermatitis. The median duration of treatment of 150 patients was 280 days (interquartile range 203-528 days). There was a significant, but not clinically relevant, increase in serum creatinine compared with the baseline level after 3 weeks of treatment with CsA and stabilization during the maintenance phase at the group level. Twenty-two (14.7%) patients had a greater than 30% increase in serum creatinine (cut-off point for clinically relevant change) compared with baseline. These patients were significantly older than the patients without a 30% increase (mean?±?standard deviation age 41.4?±?15.6 vs. 33.8?±?11.7 years (p?=?0.01)). During follow-up, all patients had a less than 30% increase in serum creatinine levels compared with baseline levels. At the group level serum creatinine levels during follow-up were not significantly different from baseline. PMID:25916428

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

    NASA Technical Reports Server (NTRS)

    Bruno, John G.

    2013-01-01

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

  9. Recycling of polyurethane-urea RIM

    SciTech Connect

    Xiao, H.X.; Kresta, J.E.; Suthar, B.; Li, X.H.

    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.

  10. Using electronic health record systems to optimize admission decisions: the Creatinine case study.

    PubMed

    Ben-Assuli, Ofir; Shabtai, Itamar; Leshno, Moshe

    2015-03-01

    Many medical organizations have implemented electronic health record (EHR) and health information exchange (HIE) networks to improve medical decision-making. This study evaluated the contribution of EHR and HIE networks to physicians by investigating whether health information technology can lead to more efficient admission decisions by reducing redundant admissions in the stressful environment of emergency. Log-files were retrieved from an integrative and interoperable EHR that serves seven main Israeli hospitals. The analysis was restricted to a group of patients seen in the emergency departments who were administered a Creatinine test. The assessment of the contribution of EHR to admission decisions used various statistical analyses and track log-file analysis. We showed that using the EHR contributes to more efficient admission decisions and reduces the number of avoidable admissions. In particular, there was a reduction in readmissions when patient history was viewed. Using EHR can help respond to the international problem of avoidable hospital readmissions. PMID:24692078

  11. Effects of urinary volume on urinary concentrations of lead, delta-aminolaevulinic acid, coproporphyrin, creatinine, and total solutes.

    PubMed Central

    Araki, S

    1980-01-01

    Urinary volume was related to urinary concentrations of lead, delta-aminolaevulinic acid (ALA), coproporphyrin (COPRO), creatinine, and total solutes in nine lead workers. On a log scale, linear relationships were found between urinary volume and the urinary concentrations. There was a certain difference in the extent of the effects of urinary volume on the urinary concentrations. For example, the concentration of creatinine was more affected by urinary volume than those of lead, ALA, and total solutes among the substances examined: similarly, the concentration of COPRO more than that of ALA. An equation was introduced to eliminate the effects of urinary volume on urinary concentrations. The effects of urinary volume on the concentrations adjusted to urinary specific gravity, osmolality, and creatinine are discussed in the light of these findings. PMID:7370193

  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. Evidence that the adverse effect of urea fertilizer on seed germination in soil is due to ammonia formed through hydrolysis of urea by soil urease

    PubMed Central

    Bremner, John M.; Krogmeier, Michael J.

    1989-01-01

    Studies using seeds of wheat (Triticum aestivum L.), rye (Secale cereale L.), barley (Hordeum vulgare L.), and corn (Zea mays L.) indicated that the adverse effect of urea fertilizer on seed germination in soil is due to ammonia formed through hydrolysis of urea by soil urease and is not due to urea itself, to urea fertilizer impurities such as biuret, or to nitrite formed by nitrification of urea nitrogen. Support for this conclusion was obtained from (i) comparison of the effects on seed germination in soil of purified urea, urea fertilizers, urea fertilizer impurities, and compounds formed by enzymatic and microbial transformations of urea in soil; (ii) studies showing that ammonia volatilized from soils treated with urea completely inhibited germination of seeds close to, but not in contact with, these soils; and (iii) experiments showing that the adverse effect of urea fertilizer on seed germination in soil was completely eliminated when the soil was autoclaved to destroy urease or was treated with phenylphosphorodiamidate to inhibit soil urease activity before treatment with urea fertilizer. PMID:16594076

  14. Hypouricemic effects of phenylpropanoid glycosides acteoside of Scrophularia ningpoensis on serum uric acid levels in potassium oxonate-pretreated Mice.

    PubMed

    Huang, Cai Guo; Shang, Yan Jun; Zhang, Jun; Zhang, Jian Rong; Li, Wen Jie; Jiao, Bin Hua

    2008-01-01

    Phenylpropanoid glycoside acteoside was extracted from the traditional Chinese medicine Scrophularia ningpoenis Hemsl. In the present study, we investigated the effects of acteoside administration on serum uric acid levels in mice rendered hyperuricemic with the uricase inhibitor potassium oxonate. When administered orally for 3 days at doses of 50, 100 and 150 mg/kg, acteoside reduced serum uric acid levels by 15.2, 23.8 and 33.1%, respectively, relative to vehicle-treated hyperuricemic mice. Importantly, in non-hyperuricemic mice, the serum uric acid levels were not affected by acetoside treatment. Acteoside also inhibited mouse liver xanthine dehydrogenase XDH and xanthine oxidase XO activity at all three doses. These results suggest that the hypouricemic action of acteoside may be attributable to its inhibition of XDH/XO activity. PMID:18306458

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

    PubMed

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

    2010-08-01

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

  16. Ratio of Urine Albumin to Creatinine Attenuates the Association of Dementia With Hip Fracture Risk

    PubMed Central

    B?žková, Petra; Fink, Howard A.; Robbins, John A.; Cauley, Jane A.; Fitzpatrick, Annette L.

    2014-01-01

    Context: Microvascular disease is a leading cause of cognitive impairment. Approximately 50% of people with a hip fracture have cognitive impairment. Objective: We tested the hypothesis that microvascular diseases of the brain (lacunar infarcts and white matter disease [WMD]), kidney (albuminuria [? 30 mg/g creatinine] and albumin creatinine ratio [ACR]), and eye (retinal vascular disorders) attenuate the association of cognitive impairment with hip fracture risk. Setting: The Cardiovascular Health Cognition Study. Patients: Three thousand, one-hundred six participants (mean age, ?79 y; 8.84 y median follow-up) with cognitive testing. Subsets received ACR testing (n=2389), brain magnetic resonance imaging scans (n = 2094), and retinal photography (n = 1098). Main Outcome Measure: Incident hip fracture. Results: There were 488 participants (16%) with mild cognitive impairment (MCI) and 564 (18%) with dementia. There were 337 incident hip fractures, of which 19% occurred in participants with MCI and 26% in participants with dementia. Adjusted hazard ratios (HR) and 95% confidence interval for hip fracture in participants with MCI were 2.45 (1.67–3.61) and for dementia 2.35 (1.57–3.52). With doubling of ACR, the HR for fracture was attenuated in participants with dementia compared with participants with normal cognition [interaction HR 0.70 (0.55–0.91)]. No such effect was found in participants with MCI. Albuminuria, lacunar infarcts, WMD, and retinal vascular disease (RVD) did not modify the association of dementia or MCI with hip fracture risk. Conclusions: ACR attenuates part of the risk of hip fracture in people with dementia, suggesting that these disorders share a common pathogenesis. PMID:25148233

  17. Carbon-Pt nanoparticles modified TiO2 nanotubes for simultaneous detection of dopamine and uric acid.

    PubMed

    Mahshid, Sara; Luo, Shenglian; Yang, Lixia; Mahshid, Sahar Sadat; Askari, Masoud; Dolati, Abolghasem; Cai, Qingyun

    2011-08-01

    The present work describes sensing application of modified TiO2 nanotubes having carbon-Pt nanoparticles for simultaneous detection of dopamine and uric acid. The TiO2 nanotubes electrode was prepared using anodizing method, followed by electrodeposition of Pt nanoparticles onto the tubes. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. The C-Pt-TiO2 nanotubes modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry methods. The modified electrode displayed high sensitivity towards the oxidation of dopamine and uric acid in a phosphate buffer solution (pH 7.00). The electro-oxidation currents of dopamine and uric acid were linearly related to the concentration over a wide range of 3.5 x 10(-8) M to 1 x 10(-5) M and 1 x 10(-7) M to 3 x 10(-5) M respectively. The limit of detection was determined as 2 x 10(-10) M for dopamine at signal-to-noise ratio of 3. The interference of uric acid was also investigated. Electro-oxidation currents of dopamine in the presence of fix amount of uric acid represented a linear behaviour towards successive addition of dopamine in range of 1 x 10(-7) M to 1 x 10(-5) M. Furthermore, in a solution containing dopamine, uric acid and ascorbic acid the overlapped oxidation peaks of dopamine and ascorbic acid could be easily separated by using C-Pt-TiO2 nanotubes modified electrode. PMID:22103066

  18. Crystal structure of a bacterial homologue of the kidney urea transporter

    SciTech Connect

    Levin, Elena J.; Quick, Matthias; Zhou, Ming

    2010-03-19

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

  19. 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

  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. Porous Cross-Linked Polyimide-Urea Networks

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Nguyen, Baochau N. (Inventor)

    2015-01-01

    Porous cross-linked polyimide-urea networks are provided. The networks comprise a subunit comprising two anhydride end-capped polyamic acid oligomers in direct connection via a urea linkage. The oligomers (a) each comprise a repeating unit of a dianhydride and a diamine and a terminal anhydride group and (b) are formulated with 2 to 15 of the repeating units. The subunit was formed by reaction of the diamine and a diisocyanate to form a diamine-urea linkage-diamine group, followed by reaction of the diamine-urea linkage-diamine group with the dianhydride and the diamine to form the subunit. The subunit has been cross-linked via a cross-linking agent, comprising three or more amine groups, at a balanced stoichiometry of the amine groups to the terminal anhydride groups. The subunit has been chemically imidized to yield the porous cross-linked polyimide-urea network. Also provided are wet gels, aerogels, and thin films comprising the networks, and methods of making the networks.

  2. Ocean urea fertilization for carbon credits poses high ecological risks.

    PubMed

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

    2008-06-01

    The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. PMID:18439628

  3. 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.

  4. 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

  5. Kinetic Studies with Ion Selective Electrodes: Determination of Creatinine in Urine with a Picrate Ion Selective Electrode: A Laboratory Experiment.

    ERIC Educational Resources Information Center

    Diamandis, E. P.; And Others

    1983-01-01

    The kinetic of the Jaffe reaction with picrate ion selective electrode (ISE) and a kinetic method for determining creatinine in urine is presented. The experiment could be used to familarize students with the application of ISE in kinetic studies and chemical analysis. (Author/JN)

  6. 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

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

    PubMed

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

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  9. Spot Protein/Creatinine Ratio in Preeclampsia as an Alternative for 24-Hour Urine Protein

    PubMed Central

    Demirci, Oya; Kumru, P?nar; Ar?nkan, Arzu; Ard?ç, Cem; Ar?soy, Resul; Tozk?r, Elif; Tando?an, Bülent; Ayvac?, Habibe; Tu?rul, Ahmet S.

    2015-01-01

    Background: Proteinuria is a major component of preeclampsia. Urine protein measurement after 24-hour urine collection is the traditional standard method for the detection of proteinuria. It is time-consuming. As an alternative, random spot sampling for a urine protein to creatinine (P/C) ratio has been investigated. Aims: The aim of the study was to determine the diagnostic accuracy of the protein to creatinine ratio (P/C) compared with 24-hour urine collection for the detection of remarkable proteinuria and to evaluate the P/C ratio for different proteinuria ranges in patients with preeclampsia. Study Design: Case-control study. Methods: Two hundred and eleven pregnant women who met the criteria of preeclampsia comprised the study group and fifty three pregnant women were taken as the control group. Spot urine specimens for measuring P/C ratio were obtained taken immediately before 24-hour urine collection. The correlation between the P/C ratio in the spot urine samples and urinary protein excretion in the 24-hour collections was examined using the Spearman correlation test. Results: It was found a good positive correlation between the P/C ratio and 24-hour protein excretion, with a correlation coefficient (r) of 0.758. The best cut-off which gave the maximum area under the curve was 0.45 for 300 mg, 0.9 for 1000 mg, 1.16 for 2000 mg, 1.49 for 3000 mg, 2.28 for 4000 mg and 2.63 for 5000 mg per 24h. A P/C ratio above 0.9 strongly predicts significant proteinuria for more than 1 gram (AUC 0.97, 95% CI: 0.94–0.99 and sensitivity, specificity, positive and negative predictive value of 91%, 95.4%, 95.2%, and 91.2%, respectively). Conclusion: The P/C ratio can be used as a screening test as a good predictor for remarkable proteinuria. The P/C ratio seems to be highly predictive for diagnosis to detect proteinuria over one gram and it could be used as a rapid alternative test in preeclamptic patients not to delay implementation treatment. PMID:25759772

  10. Comparison of Urinary Protein: Creatinine Index and Dipsticks for Detection of Microproteinuria in Diabetes Mellitus Patients

    PubMed Central

    Kumar, Anoop; Kapoor, Sangeeta; Gupta, R.C.

    2013-01-01

    Background: Proteinuria has been recognized as one of the earliest signs of renal function deterioration in Diabetes mellitus. Proteinuria occurs due to alterations in the glomerular permeability and later, due to a failure in the reabsorption of filtered protein by the tubular cells. Normally, most of the healthy adults excrete 20-150 mg of protein in urine over 24 hours. Objectives: To find out the normal urinary Protein Creatinine Index (PCI) in healthy subjects, to compare the urinary PCI of diabetic patients with that of healthy subjects and to compare the urinary PCI with dipsticks for the detection of microproteinuria. Material and Methods: This study was conducted on 28 type 2 Diabetes mellitus patients and 40 age and sex matched healthy controls. Freshly collected urine samples were tested qualitatively for the presence of proteinuria by Heller’s test, the sulfosalicylic acid test, heat-coagulation tests and urine dipsticks. Later on, the results were compared by performing a quantitative analysis of the protein in the spot urine samples by the sulfosalicylic acid method. A quantitative analysis of creatinine was done by the modified Jaffe’s test. The PCI was calculated for each of the participant in the study. The Mean and Standard Deviation (SD) of the PCI was calculated and it was compared between the two groups. Results: The normal range of the PCI which was established in this study was 60 to 220. Significantly higher amount of proteins were found to be excreted in urine in diabetic patients (25.37 ± 12.51 mg/dl) as compared to those in normal subjects (8.93 ± 3.54 mg/dl). On comparison of the PCI between the controls and the diabetic subjects, it was found to be significantly elevated in the Diabetes mellitus patients (controls = 114.65 ±47.97 and in the diabetic patients =373.04 ± 98.53) (p < 0.001). Conclusion: The PCI of a random urine sample can provide a very useful, simple and convenient method for the quantitative assessment of proteinuria, to judge the extent of kidney damage and for avoiding the drawbacks of the 24 - hr urine collections. PMID:23730632

  11. Creatinine, Arsenic Metabolism, and Renal Function in an Arsenic-Exposed Population in Bangladesh

    PubMed Central

    Peters, Brandilyn A.; Hall, Megan N.; Liu, Xinhua; Neugut, Y. Dana; Pilsner, J. Richard; Levy, Diane; Ilievski, Vesna; Slavkovich, Vesna; Islam, Tariqul; Factor-Litvak, Pam; Graziano, Joseph H.; Gamble, Mary V.

    2014-01-01

    Kidney disease is emerging as an arsenic (As)-linked disease outcome, however further evidence of this association is warranted. Our first objective for this paper was to examine the potential renal toxicity of As exposure in Bangladesh. Our second objective relates to examining whether the previously reported positive association between urinary creatinine (uCrn) and As methylation may be explained by renal function. We had hypothesized that these associations relate to supply and demand for s-adenosylmethionine, the methyl donor for both creatine synthesis and As methylation. Alternatively, renal function could influence both As and creatinine excretion, or the As metabolites may influence renal function, which in turn influences uCrn. We conducted a cross-sectional study (N?=?478) of adults, composed of a sample recruited in 2001 and a sample recruited in 2003. We assessed renal function using plasma cystatin C, and calculated the estimated glomerular filtration rate (eGFR). Consistent with renal toxicity of As, log-uAs had a marginal inverse association with eGFR in the 2003 sample (b?=??5.6, p?=?0.07), however this association was not significant in the 2001 sample (b?=??1.9, p?=?0.24). Adjustment for eGFR did not alter the associations between uCrn and the %uAs metabolites, indicating that GFR does not explain these associations. Increased eGFR was associated with increased odds of having %uInAs >12.2% (2001: OR?=?1.01, 95%CI (1.00,1.03); 2003: OR?=?1.04, 95%CI (1.01,1.07)). In the 2003 sample only, there was a negative association between eGFR and %uDMA (b?=??0.08, p?=?0.02). These results may indicate differential effects of renal function on excretion of InAs and DMA. Alternatively, a certain methylation pattern, involving decreased %InAs and increased %DMA, may reduce renal function. Given that these studies were cross-sectional, we cannot distinguish between these two possibilities. Discrepancies between the samples may be due to the higher As exposure, poorer nutrition, and lower As methylation capacity in the 2003 sample. PMID:25438247

  12. A Risk Assessment of the Jaffe vs Enzymatic Method for Creatinine Measurement in an Outpatient Population

    PubMed Central

    Schmidt, Robert L.; Straseski, Joely A.; Raphael, Kalani L.; Adams, Austin H.; Lehman, Christopher M.

    2015-01-01

    Background The Jaffe and enzymatic methods are the two most common methods for measuring serum creatinine. The Jaffe method is less expensive than the enzymatic method but is also more susceptible to interferences. Interferences can lead to misdiagnosis but interferences may vary by patient population. The overall risk associated with the Jaffe method depends on the probability of misclassification and the consequences of misclassification. This study assessed the risk associated with the Jaffe method in an outpatient population. We analyzed the discordance rate in the estimated glomerular filtration rate based on serum creatinine measurements obtained by the Jaffe and enzymatic method. Methods Method comparison and risk analysis. Five hundred twenty-nine eGFRs obtained by the Jaffe and enzymatic method were compared at four clinical decision limits. We determined the probability of discordance and the consequence of misclassification at each decision limit to evaluate the overall risk. Results We obtained 529 paired observations. Of these, 29 (5.5%) were discordant with respect to one of the decision limits (i.e. 15, 30, 45 or 60 ml/min/1.73m2). The magnitude of the differences (Jaffe result minus enzymatic result) were significant relative to analytical variation in 21 of the 29 (72%) of the discordant results. The magnitude of the differences were not significant relative to biological variation. The risk associated with misclassification was greatest at the 60 ml/min/1.73m2 decision limit because the probability of misclassification and the potential for adverse outcomes were greatest at that decision limit. Conclusion The Jaffe method is subject to bias due to interfering substances (loss of analytical specificity). The risk of misclassification is greatest at the 60 ml/min/1.73m2 decision limit; however, the risk of misclassification due to bias is much less than the risk of misclassification due to biological variation. The Jaffe method may pose low risk in selected populations if eGFR results near the 60 ml/min/1.73m2 decision limit are interpreted with caution. PMID:26599086

  13. Reinvestigation of growth of urea thiosemicarbazone monohydrate crystal

    NASA Astrophysics Data System (ADS)

    Srinivasan, Bikshandarkoil R.; Raghavaiah, Pallepogu; Nadkarni, V. S.

    2013-08-01

    The reaction of urea with thiosemicarbazide in 1:1 mole ratio in aqueous solution does not result in the formation of urea thiosemicarbazone monohydrate crystal, as reported by Hanumantharao, Kalainathan and Bhagavannarayana [Spectrochim. Acta A91 (2012) 345-351]. A reinvestigation of the reported reaction reveals that the crystal obtained is the starting material namely thiosemicarbazide, which has been unambiguously confirmed with the aid of infrared and 1H NMR spectra and single crystal X-ray structure determination. Analysis of 1H NMR spectrum reveals that thiosemicarbazide exhibits thione-thiol tautomerism in solution. In contrast, thiosemicarbazide exists as the thione tautomer in the solid state.

  14. Trends in serum creatinine testing in Oxfordshire, UK, 1993–2013: a population-based cohort study

    PubMed Central

    Oke, Jason; Shine, Brian; McFadden, Emily; Lasserson, Daniel; Perera, Rafael

    2015-01-01

    Objectives To determine how many kidney function tests are done, on whom, how frequently they are performed and how they have changed over time. Design Retrospective study of all serum creatinine, urine albumin and urine creatinine tests. Setting Primary and secondary care in Oxfordshire from 1993 to 2013. Participants Unselected population of 1?220?447 people. Main outcome measures The total number of creatinine and urinary protein tests ordered from primary and secondary care and the number of tests per year stratified by categories of estimated glomerular filtration rate (eGFR). The frequency of testing in patients having their kidney function monitored. Results Creatinine requests from primary care increased steadily from 1997 and exceeded 220?000 requests in 2013. Tests corresponding to normal kidney function (eGFR >60/mL/min/1.73?m2) constituted 59% of all kidney function tests in 1993 and accounted for 83% of all tests in 2013. Test corresponding to chronic kidney disease (CKD) stages 3–5 declined after 2007. Reduced kidney function, albuminuria, male gender, diabetes and age were independently associated with more frequent monitoring. For a female patient between 61 and 80?years and with stage 3a CKD, the average number of serum creatinine tests (95% CI) was 3.23/year (3.19 to 3.26) and for a similar woman with diabetes, the average number of tests was 5.50 (5.44 to 5.56) tests per year. Conclusions There has been a large increase in the number of kidney function tests over the past two decades. However, we found little evidence that this increase is detecting more CKD. Tests are becoming more frequent in people with and without evidence of renal impairment. Future work using a richer data source could help unravel the underlying reasons for the increased testing and determine how much is necessary and useful. PMID:26674500

  15. Effects of nitrocompounds on uric acid-utilizing microorganisms, nitrogen retention, and microbial community in laying hen manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to evaluate the effects of nitrocompounds on the growth of uric acid-utilizing microorganisms, nitrogen retention, and microbial community in laying hen manure. There were three treatments: control, 100 mM nitropropanol (NPL), and 100 mM nitropropionic acid (NPC). The mixed la...

  16. Inborn enzymatic defect as the probable cause of the formation of renal stones consisting of uric acid

    PubMed Central

    Krawczynski, Jerzy; Sagan, Zbigniew; Walajtys, Elzbieta; Ilowiecka, Krystyna

    1965-01-01

    In four persons of one family the existence of an enzymatic defect, presumably consisting of a deficiency of glutaminase in the cells of the renal tubules, is postulated, and is implied by a reduced elimination of ammonia in the urine, by a relatively low urinary pH, and by its increased titratable acidity. The most characteristic clinical symptom is irritation of the distal part of the urinary tract, connected with numerous crystals of uric acid appearing in the urinary sediment. The elimination of uric acid is normal, or even reduced, and the level of uric acid in the blood serum is also within normal limits. After the administration of glutaminic acid elimination of ammonia is further decreased and the quantity of uric acid crystals is increased. Loading with glutaminic acid may also cause an attack of renal pain in the individual suffering from this defect but the administration of ammonium chloride does not cause any increase in ammonia production. It seems probable that the enzymatic defect is connected with the presence of antigen B in the erythrocytes and that it is inherited as a dominant autosomal feature. A suitable diet to make the urine alkaline allows kidneys to function efficiently in individuals suffering from this defect. PMID:14276160

  17. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    PubMed Central

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

    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 significance, five of which are novel. Overall, the common variants associated with serum uric acid levels fall in the following nine regions: SLC2A9 (p?=?5.2×10?201), ABCG2 (p?=?3.1×10?26), SLC17A1 (p?=?3.0×10?14), SLC22A11 (p?=?6.7×10?14), SLC22A12 (p?=?2.0×10?9), SLC16A9 (p?=?1.1×10?8), GCKR (p?=?1.4×10?9), LRRC16A (p?=?8.5×10?9), and near PDZK1 (p?=?2.7×10?9). Identified variants were analyzed for gender differences. We found that the minor allele for rs734553 in SLC2A9 has greater influence in lowering uric acid levels in women and the minor allele of rs2231142 in ABCG2 elevates uric acid levels more strongly in men compared to women. To further characterize the identified variants, we analyzed their association with a panel of metabolites. rs12356193 within SLC16A9 was associated with DL-carnitine (p?=?4.0×10?26) and propionyl-L-carnitine (p?=?5.0×10?8) concentrations, which in turn were associated with serum UA levels (p?=?1.4×10?57 and p?=?8.1×10?54, respectively), forming a triangle between SNP, metabolites, and UA levels. Taken together, these associations highlight additional pathways that are important in the regulation of serum uric acid levels and point toward novel potential targets for pharmacological intervention to prevent or treat hyperuricemia. In addition, these findings strongly support the hypothesis that transport proteins are key in regulating serum uric acid levels. PMID:19503597

  20. Reactive oxygen species derived from xanthine oxidase interrupt dimerization of breast cancer resistance protein, resulting in suppression of uric acid excretion to the intestinal lumen.

    PubMed

    Ogura, Jiro; Kuwayama, Kaori; Sasaki, Shunichi; Kaneko, Chihiro; Koizumi, Takahiro; Yabe, Keisuke; Tsujimoto, Takashi; Takeno, Reiko; Takaya, Atsushi; Kobayashi, Masaki; Yamaguchi, Hiroaki; Iseki, Ken

    2015-09-01

    The prevalence of hyperuricemia/gout increases with aging. However, the effect of aging on function for excretion of uric acid to out of the body has not been clarified. We found that ileal uric acid clearance in middle-aged rats (11-12 months) was decreased compared with that in young rats (2 months). In middle-aged rats, xanthine oxidase (XO) activity in the ileum was significantly higher than that in young rats. Inosine-induced reactive oxygen species (ROS), which are derived from XO, also decreased ileal uric acid clearance. ROS derived from XO decreased the active homodimer level of breast cancer resistance protein (BCRP), which is a uric acid efflux transporter, in the ileum. Pre-administration of allopurinol recovered the BCRP homodimer level, resulting in the recovering ileal uric acid clearance. Moreover, we investigated the effects of ROS derived from XO on BCRP homodimer level directly in Caco-2 cells using hypoxanthine. Treatment with hypoxanthine decreased BCRP homodimer level. Treatment with hypoxanthine induced mitochondrial dysfunction, suggesting that the decreasing BCRP homodimer level might be caused by mitochondrial dysfunction. In conclusion, ROS derived from XO decrease BCRP homodimer level, resulting in suppression of function for uric acid excretion to the ileal lumen. ROS derived from XO may cause the suppression of function of the ileum for the excretion of uric acid with aging. The results of our study provide a new insight into the causes of increasing hyperuricemia/gout prevalence with aging. PMID:26119820

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

    PubMed Central

    2014-01-01

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

  2. Effect of castration on the urinary protein-to-creatinine ratio of male dogs.

    PubMed

    Bertieri, Marie-Blanche; Lapointe, Catherine; Conversy, Bérénice; Gara-Boivin, Carolyn

    2015-12-01

    OBJECTIVE To assess the urinary protein-to-creatinine ratio (UPCR) of healthy sexually intact male dogs and to compare the UPCR of these dogs before and after castration. ANIMALS 19 client- or shelter-owned healthy adult sexually intact male dogs. PROCEDURES Physical, hematologic, and biochemical examinations and urinalysis (including calculation of the UPCR) were performed on each dog. Dogs were then castrated, and physical examination and urinalysis (including calculation of the UPCR) were performed again at least 15 days after castration. RESULTS A dipstick test yielded positive results for protein in the urine of 10 sexually intact male dogs, but the UPCR was < 0.5 for all sexually intact male dogs. Mean UPCR for sexually intact male dogs was 0.12 (range, 0.10 to 0.32). The UPCR was < 0.2 for all castrated dogs, except for 1. Mean UPCR for all castrated dogs was 0.08 (range, 0.05 to 0.69). There was a significant difference between mean UPCR before and after castration. CONCLUSIONS AND CLINICAL RELEVANCE In this study, pathological proteinuria was not detected in sexually intact male dogs. Positive results for a urine dipstick test should be interpreted with caution in sexually intact male dogs and should be confirmed by assessment of the UPCR. An increased UPCR in sexually intact male dogs may be considered abnormal. PMID:26618734

  3. 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

  4. 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...

  5. 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

    ...solid urea from the Russian Federation (Russia). For the final results, we continue...antidumping duty order on solid urea from Russia.\\1\\ We invited interested parties...information reported by MCC EuroChem in...

  6. 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.

  7. A Journal of Integrative Biology Urea Production Capacity in the Wood Frog

    E-print Network

    Lee Jr., Richard E.

    , hyperuremia in fully hydrated frogs caused CPS I activity to decrease by $41%, suggesting that urea functions. Therefore, these animals must rely on other means to limit desiccation. Urea accumulation is one

  8. 40 CFR 418.30 - Applicability; description of the urea subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  9. 40 CFR 418.30 - Applicability; description of the urea subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  10. A genome wide association study of plasma uric acid levels in obese cases and never-overweight controls

    PubMed Central

    Li, Wei-Dong; Jiao, Hongxiao; Wang, Kai; Zhang, Clarence; Glessner, Joseph T.; Grant, Struan F.A.; Zhao, Hongyu; Hakonarson, Hakon; Price, R. Arlen

    2013-01-01

    Objective To identify plasma uric acid related genes in extremely obese and normal weight individuals using genome wide association studies (GWAS). Design and Methods Using genotypes from a GWAS focusing on obesity and thinness, we performed quantitative trait association analyses (PLINK) for plasma uric acid levels in 1,060 extremely obese individuals [body mass index (BMI) >35 kg/m2] and normal-weight controls (BMI<25kg/m2). In 961 samples with uric acid data, 924 were females. Results Significant associations were found in SLC2A9 gene SNPs and plasma uric acid levels (rs6449213, P=3.15×10?12). DIP2C gene SNP rs877282 also reached genome wide significance(P=4,56×10?8). Weaker associations (P<1×10?5) were found in F5, PXDNL, FRAS1, LCORL, and MICAL2genes. Besides SLC2A9, 3 previously identified uric acid related genes ABCG2 (rs2622605, P=0.0026), SLC17A1 (rs3799344, P=0.0017), and RREB1 (rs1615495, P =0.00055) received marginal support in our study. Conclusions Two genes/chromosome regions reached genome wide association significance (P< 1× 10?7, 550K SNPs) in our GWAS : SLC2A9, the chromosome 2 60.1 Mb region (rs6723995), and the DIP2C gene region. Five other genes (F5, PXDNL, FRAS1, LCORL, and MICAL2) yielded P<1× 10?5. Four previous reported associations were replicated in our study, including SLC2A9, ABCG2, RREB, and SLC17A1. PMID:23703922

  11. Erythrocyte permeability to urea and water: comparative study in rodents, ruminants, carnivores, humans, and birds.

    PubMed

    Liu, Lifeng; Lei, Tianluo; Bankir, Lise; Zhao, Dan; Gai, Xiaodong; Zhao, Xuejian; Yang, Baoxue

    2011-01-01

    Mammalian erythrocytes exhibit high urea permeability (P (urea)) due to UT-B expression in their cytoplasmic membrane. This high P (urea) allows fast equilibration of urea in erythrocytes during their transit in the hyperosmotic renal medulla. It also allows more urea (in addition to that in plasma) to participate in counter-current exchange between ascending and descending vasa recta, thus improving the trapping of urea in the medulla and improving urine concentrating ability. To determine if P (urea) in erythrocytes is related to diet and urine concentrating ability, we measured P (urea) in erythrocytes from 11 different mammals and 5 birds using stopped-flow light scattering. Carnivores (dog, fox, cat) exhibited high P (urea) (in x10(-5) cm/s, 5.3 ± 0.6, 3.8 ± 0.5 and 2.8 ± 0.7, respectively). In contrast, herbivores (cow, donkey, sheep) showed much lower P (urea) (0.8 ± 0.2, 0.7 ± 0.2, 1.0 ± 0.1, respectively). Erythrocyte P (urea) in human (1.1 ± 0.2), and pig (1.5 ± 0.1), the two omnivores, was intermediate. Rodents and lagomorphs (mouse, rat, rabbit) had P (urea) intermediate between carnivores and omnivores (3.3 ± 0.4, 2.5 ± 0.3 and 2.4 ± 0.3, respectively). Birds that do not excrete urea and do not express UT-B in their erythrocytes had very low values (<0.1 × 10(-5) cm/s). In contrast to P (urea), water permeability, measured simultaneously, was relatively similar in all mammals. The species differences in erythrocytes P (urea) most probably reflect adaptation to the different types of diet and resulting different needs for concentrating urea in the urine. PMID:20878327

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

    NASA Technical Reports Server (NTRS)

    Wydeven, T.; Leban, M.

    1973-01-01

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

  13. 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...

  14. INTRODUCTION Urea accumulation is a generalized amphibian response to osmotic

    E-print Network

    Lee Jr., Richard E.

    to increased plasma osmotic pressure during progressive dehydration (Muir et al., 2007). In nature, urea these is the synthesis of low-molecular-mass carbohydrates (glucose in R. sylvatica; glycerol and/or glucose in hylids the freezable fraction of body water and reduce cell dehydration and shrinkage, thereby limiting iono

  15. Reduction in slow intercompartmental clearance of urea during dialysis

    SciTech Connect

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

    1985-04-01

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

  16. Peptidyl-urea based inhibitors of soluble epoxide hydrolases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We prepared a series of amino acid derived cyclohexyl and adamantyl ureas and tested them as inhibitors of the human soluble epoxide hydrolase, and obtained very potent compounds (K(I)=15nM) that are >10-fold more soluble than previously described sEH inhibitors. While our lead compound 2 showed low...

  17. Evidence for Urea-Induced Hypometabolism in Isolated

    E-print Network

    Lee Jr., Richard E.

    Evidence for Urea-Induced Hypometabolism in Isolated Organs of Dormant Ectotherms TIMOTHY J. MUIRĂ in isolated organs of dormant ectotherms. J. Exp. Zool. 313A:28­34. When faced with unfavorable environmental conditions such as low water availability or extreme temperature, terrestrial ectotherms often enter

  18. New urea-absorbing polymers for artificial kidney machines

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  19. 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...

  20. Gelation by supramolecular dimerization of mono(urea)s.

    PubMed

    Hooper, Abigail E; Kennedy, Stuart R; Jones, Christopher D; Steed, Jonathan W

    2015-12-15

    Mono-ureido salicylic acid derivatives form hydrogen bonded dimers that mimic the gelation behaviour of covalently linked bis(urea)s. The 5-ureido salicylic acid isomers are much more effective gelators because of the lowered conjugation and less planar geometry, resulting in stronger ureaurea ?-tape hydrogen bonding interactions. PMID:26540132

  1. IRIS Toxicological Review of Urea (Interagency Science Consultation Draft)

    EPA Science Inventory

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

  2. IRIS Toxicological Review of Urea (Interagency Science Discussion Draft)

    EPA Science Inventory

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

  3. Tailoring of analytical performances of urea biosensors using nanomaterials

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  4. 75 FR 74746 - Solid Urea From Russia and Ukraine

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-01

    ... solid urea from the Union of Soviet Socialist Republics (``USSR'') (52 FR 26367). On June 29, 1992... part 207), as most recently amended at 74 FR 2847 (January 16, 2009). \\1\\ No response to this request... state (57 FR 28828). Following first five-year reviews by Commerce and the Commission,...

  5. Spectroscopic analyses on interaction of melamine, cyanuric acid and uric acid with DNA.

    PubMed

    Xie, Jinhui; Chen, Dandan; Wu, Qiong; Wang, Jun; Qiao, Heng

    2015-10-01

    In this work, the interaction of DNA with melamine (MEL), cyanuric acid (CYA) and uric acid (UA) were studied, respectively, by means of UV-vis, fluorescence, circular dichroism (CD) spectroscopy, viscosity and gel electrophoresis methods. The fluorescence quenching was used to study the interaction models of MEL, CYA and UA with DNA, respectively, and the bimolecular quenching constant (Kq), apparent quenching constant (Ksv), effective binding constant (KA) and corresponding dissociation constant (KD) and binding site number (n) were calculated by adopting Stern-Volmer, Lineweaver-Burk and Double logarithm equations. The results show that MEL, CYA and UA are all able to markedly bind to DNA, and the binding strength order is DNA-UA>DNA-CYA>DNA-MEL. It is wished that these researches would facilitate the understanding of the formation of kidney stones and gout in the body after ingesting excess MEL. PMID:25988817

  6. Electrochemical Determination of Uric Acid at CdTe Quantum Dot Modified Glassy Carbon Electrodes.

    PubMed

    Pan, Deng; Rong, Shengzhong; Zhang, Guangteng; Zhang, Yannan; Zhou, Qiang; Liu, Fenghai; Li, Miaojing; Chang, Dong; Pan, Hongzhi

    2015-01-01

    Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior of uric acid (UA) at a CdTe quantum dot (QD) modified the glassy carbon electrode (GCE). CdTe QDs, as new semiconductor nanocrystals, can greatly improve the peak current of UA. The anodic peak current of UA was linear with its concentration between 1.0×10(-6) and 4.0×10(-4) M in 0.1 M pH 5.0 phosphate buffer solution. The LOD for UA at the CdTe electrode (1.0×10(-7) M) was superior to that of the GCE. In addition, we also determined the effects of scan rate, pH, and interferences of UA for the voltammetric behavior and detection. The results indicated that modified electrode possessed excellent reproducibility and stability. Finally, a new and efficient electrochemical sensor for detecting UA was developed. PMID:26525244

  7. 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

    ...solid urea from the Russian Federation (Russia). The review covers one producer/ exporter...antidumping duty order on solid urea from Russia with respect to EuroChem on July 28...EuroChem's sales of solid urea from Russia were made in the United States at...

  8. 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

    ...solid urea from the Russian Federation (Russia) and Ukraine would likely lead to a continuation...antidumping duty orders on solid urea from Russia and Ukraine,\\1\\ pursuant to section...1, 2010); see also Solid Urea From Russia and Ukraine, 75 FR 74746 (December...

  9. 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

    ... AGENCY Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review... pesticides propionic acid and salts, case no. 4078, urea sulfate, case no. 7213, methidathion, case no. 0034... pesticides in the table below--propionic acid and salts, case 4078, urea sulfate, case no. 7213,...

  10. 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...review decisions for the pesticides propionic acid and salts, case no. 4078, urea...pesticides in the table below--propionic acid and salts, case 4078, urea...

  11. 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

  12. 75 FR 19610 - Solid Urea From the Russian Federation: Preliminary Results of Antidumping Duty Administrative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-15

    ...Commonwealth of Independent States. See Solid Urea From the Union...Antidumping Order on Solid Urea From the Union...Commonwealth of Independent States and the Baltic States...EuroChem's sales of solid urea from Russia were made in the United States at less than...

  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

    ...subject to the order is solid urea, a high-nitrogen...Schedules of the United States (HTSUS) item number...EuroChem's sales of solid urea from Russia were made in the United States at less than normal...i). \\10\\ See Solid Urea from the Russian...sold in the United States by a U.S....

  14. ORIGINAL PAPER Urea-induced hypometabolism in the hibernating wood frog

    E-print Network

    Lee Jr., Richard E.

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

  15. PHYSIOLOGY AND YIELD RESPONSES OF COTTON TO FOLIAR UREA WITH NBPT

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. Enantioselective Michael Addition/Iminium Ion Cyclization Cascades of Tryptamine-Derived Ureas

    PubMed Central

    2013-01-01

    A Michael addition/iminium ion cyclization cascade of enones with tryptamine-derived ureas under BINOL phosphoric acid (BPA) catalysis is reported. The cascade reaction tolerates a wide variety of easily synthesized tryptamine-derived ureas, including those bearing substituents on the distal nitrogen atom of the urea moiety, affording polyheterocyclic products in good yields and good to excellent enantioselectivities. PMID:23721179

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

    E-print Network

    Thirumalai, Devarajan

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

  18. Urea-Induced Denaturation of PreQ1Riboswitch Jeseong Yoon,

    E-print Network

    Thirumalai, Devarajan

    Urea-Induced Denaturation of PreQ1Riboswitch Jeseong Yoon, D. Thirumalai, and Changbong Hyeon the molecular underpinnings of urea-induced RNA denaturation. Urea displays its denaturing power in both secondary and tertiary motifs of the riboswitch structure. Our simulations reveal that the denaturation

  19. 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...

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

    E-print Network

    Kane, Andrew S.

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

  1. 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

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

    PubMed Central

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

    2011-01-01

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

  3. Use of Postoperative Creatinine to Predict Sustained Kidney Injury in Patients Undergoing Mesothelioma Surgery

    PubMed Central

    Mitani, Aya; Waikar, Sushrut S.; Ireland, Peter; Panizales, Christia; Deluke, Gretchen; Sugarbaker, David J.; Bonventre, Joseph V.; Frendl, Gyorgy

    2012-01-01

    Summary Background and objectives AKI leads to increased morbidity and mortality and progression to chronic kidney injury is a frequent consequence of AKI. Surgical treatment of mesothelioma is associated with increased risk for kidney injury. However, sustained kidney injury may limit therapeutic options for treating residual cancer. This study hypothesized that patients with significant serum creatinine (sCr) elevation within 48 hours of surgery would be at risk for sustained kidney injury. The goal was to determine the best acute sCr measure predictive of sustained kidney injury defined as a 50% increase in sCr from baseline measured 2–4 weeks after surgery. Design, setting, participants, & measurements In a prospective, observational cohort of surgical patients with mesothelioma, receiver operator characteristic curves were generated for the 24- and 48-hour absolute difference and relative sCr change over baseline in the derivation cohort (n=279). The prediction was tested in a validation cohort (n=207). The ability of various other AKI definitions to predict sustained kidney injury was evaluated. Results Sustained kidney injury occurred in 9.8% of patients in the derivation cohort. A ?59% increase in sCr 48 hours after surgery was most predictive of sustained kidney injury (c statistic=0.78). Among other AKI definitions, a sCr increase of 0.3 mg/dl in 24 hours or 0.5 mg/dl increase in 48 hours (Waikar and Bonventre criteria) also reliably predicted sustained kidney injury. Conclusions Development of clinically significant sustained kidney injury can be predicted by acute postoperative sCr elevation in patients treated for mesothelioma. PMID:22537654

  4. Evaluation of the Determination of Free Urea in Water-Soluble Liquid Fertilizers Containing Urea and Ureaforms by Urease and HPLC Methods.

    PubMed

    Hojjatie, Michael M; Abrams, Dean

    2015-12-01

    Currently there are three AOAC Official Methods for the determination of urea in fertilizers. AOAC Official Method 959.03, Urea in Fertilizers, Urease Method, First Action 1959, Final Action 1960, is based on the use of fresh commercial 1% urease solution, or preparation of such solution from urease powder in water, or from jack bean meal in water. AOAC Official Method 983.01, Urea and Methyleneureas (Water-Soluble) in Fertilizers, First Action 1983, Final Action 1984, is based on LC with a refractive index detector using water as the mobile phase and a C18 column. AOAC Official Method 2003.14, Determination of Urea in Water- Soluble Urea-Formaldehyde Fertilizer Products and in Aqueous Urea Solutions, First Action 2003, Final Action 2008, is based on LC with a UV detector using acetonitrile-water (85 + 15, v/v) mobile phase and a propylamine column. The urea method, AOAC Official Method 959.03, is very much dependent on the nature of the urease enzyme. The method was developed in 1960 and used for simple urea fertilizer solutions. With the advent of complex fertilizer compositions, especially with the class of liquid triazone fertilizers and water-soluble urea forms, the analyses of free urea in these fertilizers by the urease method is often inaccurate and inconsistent. AOAC Official Method 983.01 is not always reliable due to the interference of some of the components of these fertilizers, and due to the fact that the use of water as the mobile phase does not always separate the free urea from other components. AOAC Official Method 2003.14 was subjected to ring test studies that showed it could be used for the determination of "free urea" in these classes of fertilizers with good accuracy and precision. PMID:26651558

  5. Continuous multi-phase feeding of broiler chickens 

    E-print Network

    Nasril

    2005-02-17

    (ureoteley) and (2) its conversion to uric acid (uricoteley). In both mechanisms, the primary ammonia-detoxyfying reaction is located within the mitochondrial matrix of liver cells. The end products of nitrogen metabolism excreted in the urine of birds... include urates, ammonia, urea, and small amount of creatinine, amino acids and purines. Of these, urates are the prodominant compounds under all circumstances, though ammonia may account for as much as 25% of total nitrogen (Goldstein and Skadhauge...

  6. Serum Uric Acid and Renal Transplantation Outcomes: At Least 3-Year Post-transplant Retrospective Multivariate Analysis

    PubMed Central

    Zhang, Kun; Gao, Baoshan; Wang, Yuantao; Wang, Gang; Wang, Weigang; Zhu, Yaxiang; Yao, Liyu; Gu, Yiming; Chen, Mo; Zhou, Honglan; Fu, Yaowen

    2015-01-01

    Since the association of serum uric acid and kidney transplant graft outcome remains disputable, we sought to evaluate the predictive value of uric acid level for graft survival/function and the factors could affect uric acid as time varies. A consecutive cohort of five hundred and seventy three recipients transplanted during January 2008 to December 2011 were recruited. Data and laboratory values of our interest were collected at 1, 3, 6, 12, 24 and 36 months post-transplant for analysis. Cox proportional hazard model, and multiple regression equation were built to adjust for the possible confounding variables and meet our goals as appropriate. The current cohort study lasts for 41.86 ± 15.49 months. Uric acid level is proven to be negatively associated with eGFR at different time point after adjustment for age, body mass index and male gender (standardized ? ranges from -0.15 to -0.30 with all P<0.001).Males with low eGFR but high level of TG were on CSA, diuretics and RAS inhibitors and experienced at least one episode of acute rejection and diabetic issue were associated with a higher mean uric acid level. Hyperuricemia was significantly an independent predictor of pure graft failure (hazard ratio=4.01, 95% CI: 1.25-12.91, P=0.02) after adjustment. But it was no longer an independent risk factor for graft loss after adjustment. Interestingly, higher triglyceride level can make incidence of graft loss (hazard ratio=1.442, for each unit increase millimoles per liter 95% CI: 1.008-2.061, P=0.045) and death (hazard ratio=1.717, 95% CI: 1.105-2.665, P=0.016) more likely. The results of our study suggest that post-transplant elevated serum uric acid level is an independent predictor of long-term graft survival and graft function. Together with the high TG level impact on poor outcomes, further investigations for therapeutic effect are needed. PMID:26208103

  7. Early Acute Kidney Injury based on Serum Creatinine or Cystatin C in Intensive Care Unit after Major Trauma

    PubMed Central

    Zand, Farid; Sabetian, Golnar; Abbasi, Ghasem; Rezaianzadeh, Abbas; Salehi, Alireza; Khosravi, Abbas; Geramizadeh, Bita; Taregh, Shuja Ulhaq; Javadpour, Shohreh

    2015-01-01

    Background: Acute kidney injury (AKI) is a common problem in critically ill patients and is independently associated with increased morbidity and mortality. Recently, serum cystatin C has been shown to be superior to creatinine in early detection of renal function impairment. We compared estimated GFR based on serum cystatin C with estimated GFR based on serum creatinine for early detection of renal dysfunction according to the RIFLE criteria. Methods: During 9 months, three hundred post trauma patients that were referred to the intensive care unit of a referral trauma hospital were recruited. Serum creatinine and serum cystatin C were measured and the estimated GFR within 24 hours of ICU admission was calculated. The primary outcome was the incidence of AKI according to the RIFLE criteria within 2nd to 7th day of admission. Results: During the first week of ICU admission, 21% of patients experienced AKI. After adjusting for major confounders, only the patients with first day’s serum cystatin level higher than 0.78 mg/l were at higher risk of first week AKI (OR=6.14, 95% CI: 2.5-14.7, P<0.001). First day’s serum cystatin C and injury severity score were the major risk factors for ICU mortality (OR=3.54, 95% CI: 1.7-7.4, P=0.001) and (OR=4.6, 95% CI: 1.5-14, P=0.007), respectively. Conclusion: Within 24 hours after admission in ICU due to multiple trauma, high serum cystatin C level may have prognostic value in predicting early AKI and mortality during ICU admission. However, such correlation was not seen neither with creatinine nor cystatin C based GFR. PMID:26538776

  8. Synthesis and stacked conformations of symmetrical and unsymmetrical oligo-ureas of metaphenylenediamine.

    PubMed

    Clayden, Jonathan; Lemičgre, Loďc; Helliwell, Madeleine

    2007-03-30

    The addition of substituted anilines to nitro-substituted isocyanates followed by reduction generates new aniline-substituted ureas, which can be further extended in a one- or two-directional iterative manner to form oligomeric ureas based on a m-phenylenediamine monomer. Oligo-ureas with up to eight urea linkages are reported. Fully N-substituted oligo-ureas are crystalline, and the X-ray crystal structures display ring-stacked conformations. 1H NMR studies indicate that the stacked conformation persists in solution. PMID:17343415

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

    PubMed

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

    2015-05-15

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

  10. Adventures with Creatinine and eGFR - A National, International and Personal Story – AACB Roman Lecture 2014

    PubMed Central

    Jones, Graham R.D.

    2015-01-01

    In Australia and New Zealand today there is a commonality in all laboratories in many areas of testing related to Chronic Kidney Disease (CKD). These include creatinine assay standardisation, estimated Glomerular Filtration Rate (eGFR) reporting and the use of common units for serum creatinine and eGFR. This is supported by a single definition for diagnosis and staging of CKD, agreed indications for who and how to test together with detailed advice on test interpretation and patient management provided by our nephrology colleagues. These outcomes are the product of a decade of effort within Australia and New Zealand with collaboration between clinical disciplines and amongst laboratories. These local activities have been based on and supported by international actions in assay standardisation, eGFR formula development, understanding of clinical outcomes and guideline development. It is my belief that the local implementation of the current laboratory-based CKD testing processes is an outstanding example of good laboratory practice. This paper outlines the local and international activities and provides a view of my personal adventures with creatinine and eGFR. PMID:26224897

  11. 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

  12. High and Low Affinity Urea Root Uptake: Involvement of NIP5;1.

    PubMed

    Yang, Huayiu; Menz, Jochen; Häussermann, Iris; Benz, Martin; Fujiwara, Toru; Ludewig, Uwe

    2015-08-01

    Urea is the most widespread nitrogen (N) fertilizer worldwide and is rapidly degraded in soil to ammonium by urease. Ammonium is either taken up by plant roots or is further processed to nitrate by soil microorganisms. However, urea can be taken up by roots and is further degraded to ammonium by plant urease for assimilation. When urea is supplied under sterile conditions, it acts as a poor N source for seedlings or adult Arabidopsis thaliana plants. Here, the gene expression of young seedlings exposed to urea and ammonium nitrate nutrition was compared. Several primary metabolism and transport genes, including those for nitrate and urea, were differentially expressed in seedlings. However, urease and most major intrinsic proteins were not differentially expressed, with the exception of NIP6;1, a urea-permeable channel, which was repressed. Furthermore, little overlap with the gene expression with ammonium as the sole N source was observed, confirming that pure urea nutrition is not associated with the ammonium toxicity syndrome in seedlings. The direct root uptake of urea was increased under boron deficiency, in both the high and low affinity range. This activity was entirely mediated by the NIP5;1 channel, which was confirmed to transport urea when expressed in oocytes. The uptake of urea in the high and low affinity range was also determined for maize and wheat roots. The urea uptake by maize roots was only about half that of wheat, but was not stimulated by boron deficiency or N deficiency in either species. This analysis identifies novel components of the urea uptake systems in plants, which may become agronomically relevant to urea uptake and utilization, as stabilized urea fertilizers become increasingly popular. PMID:25957355

  13. Clinical evaluation of analytical variations in serum creatinine measurements: why laboratories should abandon Jaffe techniques

    PubMed Central

    2012-01-01

    Background Non-equivalence in serum creatinine (SCr) measurements across Dutch laboratories and the consequences hereof on chronic kidney disease (CKD) staging were examined. Methods National data from the Dutch annual external quality organization of 2009 were used. 144 participating laboratories examined 11 pairs of commutable, value-assigned SCr specimens in the range 52–262 ?mol/L, using Jaffe or enzymatic techniques. Regression equations were created for each participating laboratory (by regressing values as measured by participating laboratories on the target values of the samples sent by the external quality organization); area under the curves were examined and used to rank laboratories. The 10th and 90th percentile regression equation were selected for each technique separately. To evaluate the impact of the variability in SCr measurements and its eventual clinical consequences in a real patient population, we used a cohort of 82424 patients aged 19–106 years. The SCr measurements of these 82424 patients were introduced in the 10th and 90th percentile regression equations. The newly calculated SCr values were used to calculate an estimated glomerular filtration rate (eGFR) using the 4-variable Isotope Dilution Mass Spectrometry traceable Modification of Diet in Renal Disease formula. Differences in CKD staging were examined, comparing the stratification outcomes for Jaffe and enzymatic SCr techniques. Results Jaffe techniques overestimated SCr: 21%, 12%, 10% for SCr target values 52, 73 and 94 ?mol/L, respectively. For enzymatic assay these values were 0%, -1%, -2%, respectively. eGFR using the MDRD formula and SCr measured by Jaffe techniques, staged patients in a lower CKD category. Downgrading to a lower CKD stage occurred in 1-42%, 2-37% and 12–78.9% of patients for the 10th and 90th percentile laboratories respectively in CKD categories 45–60, 60–90 and >90 ml/min/1.73 m2. Using enzymatic techniques, downgrading occurred only in 2-4% of patients. Conclusions Enzymatic techniques lead to less variability in SCr measurements than Jaffe techniques, and therefore result in more accurate staging of CKD. Therefore the specific enzymatic techniques are preferably used in clinical practice in order to generate more reliable GFR estimates. PMID:23043743

  14. A study of nephron function in normal tropical residents using the creatinine and lithium clearances

    NASA Astrophysics Data System (ADS)

    Arthur, S. K.; Nyarko, A. K.; Asaku, J. Y.; Akyeampong, A. Y.

    The kidney bears the brunt of the demands of a tropical climate for water and electrolyte homeostasis. We hypothesised that a tropical climate may cause adaptive changes in the entire organism leading to altered renal function in our subjects. Hence renal function data for residents of a temperate climate may not be applic- able to tropical residents. We therefore sought to elucidate renal function in subjects residing in a tropical climate. We used lithium clearance, CLi, a non-invasive tool for assessing proximal tubular function in humans, and endogenous creatinine clearance, CCr, to estimate proximal tubular function and glomerular function, respectively, in our subjects. We did this in order to establish whether or not nephron function in our subjects differs from that for residents of a temperate climate. Nineteen male and 12 female Ghanaian subjects aged between 15 and 48 years were studied. The estimated GCr was 117.3+/-6.6 ml/min for male subjects and 97+/-6.4 ml/min for female subjects. CLi was 20.3+/-1.6 ml/min for male and 19.1+/-0.4 ml/min for female subjects, respectively. The estimated absolute reabsorption rate of fluid of proximal tubules was 97.0+/-6.0 ml/min for males and 78.1+/-6.0 ml/min for females. The percentage proximal fluid reabsorption for male and female subjects was 81.2+/-1.4 and 79.5+/-1.6, respectively. The differences between male and female values (mean+/-SEM) were not statistically significant. The data suggest that the proximal tubule in residents of a tropical climate may reabsorb more fluid compared to that in residents of a temperate climate. Our values for proximal tubular reabsorption are higher than those reported for residents of a temperature climate. Our estimate of glomerular filtration, however, is similar to published data for Caucasians. The difference in proximal tubular function may reflect possible renal adaptation to a hot, humid climate. We conclude that renal function of tropical residents differs from that of residents of a temperate climate. This difference may be due to renal adaptation to the hot, tropical climate.

  15. Molecular-dynamics simulations of urea nucleation from aqueous solution

    PubMed Central

    Salvalaglio, Matteo; Perego, Claudio; Giberti, Federico; Mazzotti, Marco; Parrinello, Michele

    2015-01-01

    Despite its ubiquitous character and relevance in many branches of science and engineering, nucleation from solution remains elusive. In this framework, molecular simulations represent a powerful tool to provide insight into nucleation at the molecular scale. In this work, we combine theory and molecular simulations to describe urea nucleation from aqueous solution. Taking advantage of well-tempered metadynamics, we compute the free-energy change associated to the phase transition. We find that such a free-energy profile is characterized by significant finite-size effects that can, however, be accounted for. The description of the nucleation process emerging from our analysis differs from classical nucleation theory. Nucleation of crystal-like clusters is in fact preceded by large concentration fluctuations, indicating a predominant two-step process, whereby embryonic crystal nuclei emerge from dense, disordered urea clusters. Furthermore, in the early stages of nucleation, two different polymorphs are seen to compete. PMID:25492932

  16. CVD synthesis of nitrogen-doped graphene using urea

    NASA Astrophysics Data System (ADS)

    Zhang, CanKun; Lin, WeiYi; Zhao, ZhiJuan; Zhuang, PingPing; Zhan, LinJie; Zhou, YingHui; Cai, WeiWei

    2015-10-01

    This work provides an effective low-cost synthesis and in-depth mechanistic study of high quality large-area nitrogen-doped graphene (NG) films. These films were synthesized using urea as nitrogen source and methane as carbon source, and were characterized by scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The N doping level was determined to be 3.72 at.%, and N atoms were suggested to mainly incorporated in a pyrrolic N configuration. All distinct Raman peaks display a shift due to the nitrogen-doping and compressive strain. The increase in urea concentration broadens the D and 2 D peak's Full Width at Half Maximum (FWHM), due to the decrease of mean free path of phonons. The N-doped graphene exhibited an n-type doping behavior with a considerably high carrier mobility of about 74.1 cm2/(V s), confirmed by electrical transport measurements.

  17. Reverse osmosis membrane of high urea rejection properties. [water purification

    NASA Technical Reports Server (NTRS)

    Johnson, C. C.; Wydeven, T. J. (inventors)

    1980-01-01

    Polymeric membranes suitable for use in reverse osmosis water purification because of their high urea and salt rejection properties are prepared by generating a plasma of an unsaturated hydrocarbon monomer and nitrogen gas from an electrical source. A polymeric membrane is formed by depositing a polymer of the unsaturated monomer from the plasma onto a substrate, so that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.

  18. Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite

    PubMed Central

    Das, Gautam; Yoon, Hyon Hee

    2015-01-01

    An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (?A · cm?2·mM?1. The biosensor achieved a broad linear range of detection (0.12–12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection. PMID:26346240

  19. Antibacterial kaolinite/urea/chlorhexidine nanocomposites: Experiment and molecular modelling

    NASA Astrophysics Data System (ADS)

    Holešová, Sylva; Valášková, Marta; Hlavá?, Dominik; Madejová, Jana; Samlíková, Magda; Tokarský, Jonáš; Pazdziora, Erich

    2014-06-01

    Clay minerals are commonly used materials in pharmaceutical production both as inorganic carriers or active agents. The purpose of this study is the preparation and characterization of clay/antibacterial drug hybrids which can be further included in drug delivery systems for treatment oral infections. Novel nanocomposites with antibacterial properties were successfully prepared by ion exchange reaction from two types of kaolinite/urea intercalates and chlorhexidine diacetate. Intercalation compounds of kaolinite were prepared by reaction with solid urea in the absence of solvents (dry method) as well as with urea aqueous solution (wet method). The antibacterial activity of two prepared samples against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was evaluated by finding the minimum inhibitory concentration (MIC). Antibacterial studies of both samples showed the lowest MIC values (0.01%, w/v) after 1 day against E. faecalis, E. coli and S. aureus. A slightly worse antibacterial activity was observed against P. aeruginosa (MIC 0.12%, w/v) after 1 day. Since samples showed very good antibacterial activity, especially after 1 day of action, this means that these samples can be used as long-acting antibacterial materials. Prepared samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The experimental data are supported by results of molecular modelling.

  20. Comparative formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in creatinine/phenylalanine and creatinine/phenylalanine/4-oxo-2-nonenal reaction mixtures.

    PubMed

    Zamora, Rosario; Alcón, Esmeralda; Hidalgo, Francisco J

    2013-05-01

    The comparative formation of the heterocyclic aromatic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in both creatinine/phenylalanine (CRN/Phe) and creatinine/phenylalanine/4-oxo-2-nonenal (CRN/Phe/ON) systems was studied to analyse the ability of lipid-derived reactive carbonyls to promote PhIP formation. Although PhIP was produced to some extent in the CRN/Phe system, the presence of the oxidized lipid increased considerably the amount of PhIP produced. This increase seemed to be a consequence of the decrease in the E(a) of the reaction when the lipid was present, which diminished from 112.9 to 80.9 kJ/mol. On the other hand, the addition of the lipid did not seem to produce PhIP by an alternative mechanism because PhIP was formed analogously in both CRN/Phe and CRN/Phe/ON systems as a function of pH, creatinine concentration, phenylalanine concentration, time, temperature, oxygen concentration in the reaction atmosphere, and the addition of different amounts of ammonia. All these results suggest that the ability of lipid oxidation products to produce PhIP is related to their capacity to induce the Strecker degradation of phenylalanine to phenylacetaldehyde. Therefore, any other reactive carbonyl compound that can produce the Strecker degradation of phenylalanine should also be considered as a potential inducer of PhIP formation under appropriate conditions. PMID:23265474

  1. Non-enzymatic detection of urea using unmodified gold nanoparticles based aptasensor.

    PubMed

    Kumar, Piyush; Lambadi, Paramesh Ramulu; Navani, Naveen Kumar

    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 232 nM. 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 150 mM 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

  2. Synergistic behavior of glycine betaine-urea mixture: A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Kumar, Narendra; Kishore, Nand

    2013-09-01

    Glycine betaine (GB) is one of the most important osmolyte which is known to stabilize proteins as well as counteract the denaturing effect of urea. There have been many studies indicating protein stabilization and counteraction of the effect of urea by GB. However, the exact mechanism of counteraction is still debated and is of important research interest. In this study, distribution functions, hydrogen bonds, and energetics were analysed to understand different interactions between GB and urea, and their solvation properties in presence of each other. The results show that in the GB-urea mixture, GB acted as a stronger osmolyte and urea became a weaker denaturing agent than its individual counterparts. The increase in the solvation of urea and GB in GB-urea mixture and their mutual interactions through hydrogen bonding and coulombic energy resulted in more involvement of GB and urea with solvent as well as with themselves. This might result in the increase of the exclusion of GB from protein surface and decrease in the protein-urea interactions in the mixture. This synergistic behavior might be the prime reason for the counteraction of denaturing effect of urea by GB.

  3. ENSURING THE AVAILABILITY AND RELIABILITY OF UREA DOSING FOR ON-ROAD AND NON-ROAD

    SciTech Connect

    Barton, G; Lonsdale, B

    2003-08-24

    The purpose of this presentation is to address two important issues. The first issue is nationwide availability of urea. The second is assurance by the engine maker that the engine cannot operate without urea. In regard to the first issue, North American urea production can support SCR needs for the Heavy Duty truck industry. The existing distribution methods, pathways and technology could be utilized for urea supply with no new invention required. Urea usage and storage capacity on vehicles would support long distances between tank refills, as SCR could be initially rolled out with a limited infrastructure. The price of urea should be less than diesel fuel and urea SCR should have a fuel economy advantage over competing technologies. It can be in place by 2007. In regard to the second issue, sensor technology exists to monitor urea tank level and verify that the fluid in the tank is urea. NOx sensors are available to monitor tailpipe NOx, ensuring the entire SCR system is functioning properly, and inferring that urea is in the system. The monitoring system could be used to monitor compliance, record faults, and initiate enforcement actions as necessary. The monitoring system could initiate actions to encourage compliance.

  4. Accuracy of serum uric acid as a predictive test for maternal complications in pre-eclampsia: bivariate meta-analysis and decision analysis.

    PubMed

    Koopmans, Corine M; van Pampus, Maria G; Groen, Henk; Aarnoudse, Jan G; van den Berg, Paul P; Mol, Ben W J

    2009-09-01

    The aim of this study is to determine the accuracy and clinical value of serum uric acid in predicting maternal complications in women with pre-eclampsia. An existing meta-analysis on the subject was updated. The accuracy of serum uric acid for the prediction of maternal complications was assessed with a bivariate model estimating a summary Receiver Operating Characteristic (sROC) curve. Subsequently, a clinical decision analysis was performed, in which three alternative strategies were modelled: (I) expectant management with monitoring until spontaneous labour; (II) induction of labour; (III) serum uric acid as test for predicting maternal complications. In the latter strategy, accuracy data of serum uric acid derived from the sROC curve were used to assess the value of serum uric acid in the management of women with pre-eclampsia. In this strategy, women with an increased serum uric acid were supposed to have labour induced, whereas women with serum uric acid levels below the threshold were managed expectantly. The decision whether to use the policy expectant management, to induce labour or to test serum uric acid levels, is based on the expected utility of each strategy. The expected utility depends on the probability of occurrence of severe maternal complications (i.e. severe hypertension, haemolysis, elevated liver enzymes and low platelet count (HELLP syndrome) or eclampsia) and the mode of delivery (caesarean section versus vaginal delivery). Valuation of the outcomes was performed using a distress ratio, which expresses how much worse a complication of pre-eclampsia is valued as compared to a caesarean section. Eight studies, testing 1565 women with pre-eclampsia, met the inclusion criteria. If the distress ratio was 10, the strategy regarding serum uric acid would be the preferred strategy when the probability of complications was between 2.9 and 6.3%. At higher complication rates induction of labour would be preferred, whereas at lower complication rates expectant management would be the best treatment option. These findings were stable in sensitivity analyses, using different distress ratios. Based on the decision analysis, serum uric acid seems to be a useful test in the management of pre-eclampsia under realistic assumptions. PMID:19540647

  5. Multicenter uric acid biosensor based on tetrapod-shaped ZnO nanostructures.

    PubMed

    Lei, Yang; Liu, Xi; Yan, Xiaoqin; Song, Yu; Kang, Zhuo; Luo, Ning; Zhang, Yue

    2012-01-01

    In this work, we developed a tetrapod-shaped ZnO nanostructure (T-ZnO) biosensor to determine uric acid (UA), which is the primary end product of purine metabolism. The as-fabricated UA sensor presents a higher performance than that of the reported biosensors based on ZnO nanorods and ZnS quantum dots, etc. High-quality ZnO nanotetrapods were characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectra (EDX), X-ray diffraction (XRD) and Raman spectroscopy, respectively. A high affinity of uricase/ZnO to UA was revealed by cyclic voltammograms. The biosensor performance has been systematically investigated by amperometric response measurements. A fast current response time is within 9 s. It was also found that the uricase/T-ZnO biosensor presented a high and reproducible sensitivity of 80.0 microA cm(-2) mM(-1) and an experiment limit of detection of 0.8 microM. This study provides an insight utilizing the unique ZnO nanostructure to develop the highly sensitive and rapidly responsive nano-bio devices. PMID:22524012

  6. Synthesis of water soluble chitosan stabilized gold nanoparticles and determination of uric acid

    NASA Astrophysics Data System (ADS)

    Lanh Le, Thi; Khieu Dinh, Quang; Hoa Tran, Thai; Nguyen, Hai Phong; Le Hien Hoang, Thi; Hien Nguyen, Quoc

    2014-06-01

    Gold nanoparticles (Au-NPs) have been successfully synthesized by utilizing water soluble chitosan as reducing and stabilizing agent. The colloidal Au-NPs were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). The results showed that the colloidal Au-NPs had a plasmon absorption band with maximum wavelength in the range of 520-526 nm and the diameters were about 8-15 nm. In addition, a new Au-NPs-modified electrode was fabricated by self-assembling Au-NPs to the surface of the L-cysteine-modified glassy carbon electrode (Au-NPs/L-Cys/GCE). The Au-NPs-modified electrode showed an excellent character for electro-catalytic oxidization of uric acid (UA) in 0.1 mol L-1 phosphate buffer solution (pH 3.2). Using differential pulse anodic stripping voltammetry (DP-ASV), a high selectivity for determination of UA has been explored for the Au-NPs-modified electrode. DP-ASV peak currents of UA increased linearly with their concentration at the range of 2.0 × 10-6 to 4.0 × 10-5 mol L-1 with the detection limit of 2.7 × 10-6 mol L-1 for UA. The proposed method was applied for the detection of UA in human urine and serum samples with satisfactory results.

  7. Effects of uric acid on endothelial dysfunction in early chronic kidney disease and its mechanisms

    PubMed Central

    2013-01-01

    Background An increase in serum uric acid (UA) occurs during the early and middle stages of chronic kidney disease (CKD) and aggravates the deterioration of kidney function. This study aims to explore the relation between UA and endothelial dysfunction in early CKD and its mechanisms in a murine model. Methods The experimental animals were randomly divided into three groups (n?=?10): sham-operation group (control group), right nephrectomy only group (CKD group) and right nephrectomy with oxonic potassium group (CKD with hyperuricemia group). Furthermore, we analyzed the relation between UA and endothelial dysfunction indices in early CKD as well as its mechanisms. Results Linear regression analysis showed that the level of serum UA had a significant positive correlation with serum endothelin-1 and the percentage of collagen I positive area, but a negative correlation with serum nitric oxide (NO) and NO/endothelin-1 ratio. In addition, the level of serum UA had significant positive correlations with serum malonaldehyde, serum C-reactive protein, serum oxidatively-modified low-density lipoprotein and serum low-density lipoprotein, but a negative correlation with serum superoxide dismutase. Conclusions Endothelial dysfunction in the CKD group was significant and had a positive correlation with the level of serum UA. Endothelial dysfunction in early CKD with hyperuricemia is perhaps related to oxidative stress, micro-inflammation and lipid oxidation. PMID:23895583

  8. The Relationship between Uric Acid Levels and Huntington’s Disease Progression

    PubMed Central

    Auinger, Peggy; Kieburtz, Karl; McDermott, Michael P.

    2009-01-01

    Uric acid (UA) may be associated with the progression of Parkinson’s disease and related neurodegenerative conditions; however, its association with Huntington’s disease (HD) progression has not been explored. A secondary analysis of 347 subjects from the CARE-HD clinical trial was performed to examine the relationship between baseline UA levels and the level of functional decline in HD. Outcomes included change in scores at 30 months for the Unified Huntington’s Disease Rating Scale components. There was less worsening of total functional capacity over time with increasing baseline UA levels (adjusted mean worsening in scores: 3.17, 2.99, 2.95, 2.28, 2.21, from lowest to highest UA quintile, p=0.03). These data suggest a possible association between higher UA levels and slower HD progression, particularly as measured by total functional capacity. If confirmed, UA could be an important predictor and potentially modifiable factor affecting the rate of HD progression. PMID:20063429

  9. Serum Uric Acid, Gender, and Low Ankle Brachial Index in Adults With High Cardiovascular Risk.

    PubMed

    Zhan, Yiqiang; Dong, Ying; Tang, Zheng; Zhang, Fen; Hu, Dayi; Yu, Jinming

    2015-08-01

    Uric acid (UA) has been reported to be associated with cardiovascular disease (CVD) in caucasians. However, it is unclear whether this association remains significant in a Chinese population. The present study aimed to investigate the association between UA and low ankle brachial index (ABI), a measurement of peripheral arterial disease, in Chinese patients. A total of 6262 hospital-based patients with high CVD risk were enrolled. Low ABI was defined as ABI ?0.9 in either side. Low ABI was detected in 1390 (22.2%) patients. Higher UA was significantly associated with higher risk of low ABI and modified by gender (P = .0045). After adjusting for age, body mass index, total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, fasting glucose, hypertension, and smoking, participants in the highest quartile of UA exhibited 37% (odds ratio [OR]:1.37, 95% confidence interval [CI]: 1.03-1.82) higher risk of low ABI compared to those in the lowest quartile in men, while OR (95% CI) was 1.69 (1.29-2.22) for women. However, when kidney function was further adjusted, the associations were attenuated in both men and women and were significant only in women. The results were suggestive of higher UA associating with higher risk of low ABI in women, and the association was largely driven by kidney function, especially in men. PMID:25564679

  10. EGCG Attenuates Uric Acid-Induced Inflammatory and Oxidative Stress Responses by Medicating the NOTCH Pathway

    PubMed Central

    Xie, Hua; Sun, Jianqin; Chen, Yanqiu; Zong, Min; Li, Shijie; Wang, Yan

    2015-01-01

    Background. The aim of this study is to investigate whether (-)-epigallocatechin-3-gallate (EGCG) can prevent the UA-induced inflammatory effect of human umbilical vein endothelial cells (HUVEC) and the involved mechanisms in vitro. Methods. HUVEC were subjected to uric acid (UA) with or without EGCG treatment. RT-PCR and western blots were performed to determine the level of inflammation marker. The antioxidant activity was evaluated by measuring scavenged reactive oxygen species (ROS). Functional studies of the role of Notch-1 in HUVEC lines were performed using RNA interference analyses. Results. UA significantly increased the expressions of IL-6, ICAM-1, TNF-?, and MCP-1 and the production of ROS in HUVEC. Meanwhile, the expression of Notch-1 and its downstream effects significantly increased. Using siRNA, inhibition of Notch-1 signaling significantly impeded the expressions of inflammatory cytokines under UA treatment. Interestingly, EGCG suppressed the expressions of inflammatory cytokines and the generation of ROS. Western blot analysis of Notch-1 showed that EGCG significantly decreased the expressions of inflammatory cytokines through Notch-1 signaling pathways. Conclusions. In summary, our findings indicated that Notch-1 plays an important role in the UA-induced inflammatory response, and the downregulation of Notch-1 by EGCG could be an effective approach to decrease inflammation and oxidative stress induced by UA. PMID:26539255

  11. Development of Anodic Titania Nanotubes for Application in High Sensitivity Amperometric Glucose and Uric Acid Biosensors

    PubMed Central

    Lee, Hsiang-Ching; Zhang, Li-Fan; Lin, Jyh-Ling; Chin, Yuan-Lung; Sun, Tai-Ping

    2013-01-01

    The purpose of this study was to develop novel nanoscale biosensors using titania nanotubes (TNTs) made by anodization. Titania nanotubes were produced on pure titanium sheets by anodization at room temperature. In this research, the electrolyte composition ethylene glycol 250 mL/NH4F 1.5 g/DI water 20 mL was found to produce the best titania nanotubes array films for application in amperometric biosensors. The amperometric results exhibit an excellent linearity for uric acid (UA) concentrations in the range between 2 and 14 mg/dL, with 23.3 (?A·cm?2)·(mg/dL)?1 UA sensitivity, and a correlation coefficient of 0.993. The glucose biosensor presented a good linear relationship in the lower glucose concentration range between 50 and 125 mg/dL, and the corresponding sensitivity was approximately 249.6 (?A·cm?2)·(100 mg/dL)?1 glucose, with a correlation coefficient of 0.973. PMID:24152934

  12. 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

  13. Uric acid enhances the antitumor immunity of dendritic cell-based vaccine.

    PubMed

    Wang, Yihan; Ma, Xuelei; Su, Chao; Peng, Bin; Du, Jing; Jia, Hongyuan; Luo, Min; Fang, Chunju; Wei, Yuquan

    2015-01-01

    Uric acid (UA) released from dying cells has been recognized by the immune system as a danger signal. In response to UA, dendritic cells (DC) in the immune system mature and enhance the T cell response to foreign antigens. It is conceivable that the antitumor immunity of a tumor vaccine could be promoted by the administration of UA. To test this concept, we applied UA as an adjuvant to a DC-based vaccine, and discovered that the administration of UA as an adjuvant significantly enhanced the ability of the tumor lysate-pulsed DC vaccine in delaying the tumor growth. The antitumor activity was achieved with adoptively transferred lymphocytes, and both CD8(+) T cells and NK cells were required to achieve effective immunity. This resulted in an increased accumulation of activated CD8(+) T cells and an elevated production of IFN-?. Collectively, our study shows that the administration of UA enhances the antitumor activity of tumor lysate-pulsed DC vaccine, thus providing the preclinical rationale for the application of UA in DC-based vaccine strategies. PMID:26553557

  14. Effects of composite restorations on nitric oxide and uric acid levels in saliva

    PubMed Central

    Akgul, Nilgun; Gul, Pinar; Alp, Hamit Hakan; Kiziltunc, Ahmet

    2015-01-01

    Background and Aims: Dental materials that are used in dentistry should be harmless to oral tissues, and should, therefore, not contain any leachable toxic and diffusible substances capable of causing side effects. This study was intended to investigate the effects on salivary nitric oxide (NO) and uric acid (UA) levels after application of dental composite filling materials to healthy volunteers. Materials and Methods: A total of 52 individuals (32 female and 20 male) participated in the study. Filtek Z250 composite filling material (3M ESPE, St Paul, MN, USA) was applied to healthy volunteers. Saliva samples were collected before restoration (baseline) and 1 h, 1-day, 7 days, and 30 days after restoration. NO concentrations were measured using the Griess reaction method, and UA was measured using an enzymatic method. Data were analyzed using repeated measures ANOVA and the Bonferroni post-hoc test (? =5%). Results: NO values increased statistically significant after 7 days (P < 0.05). In addition, lower UA levels were determined compared to the baseline levels, but the difference was not statistically significant (P > 0.05). There was no correlation between NO and UA levels in saliva (P > 0.05). Conclusion: Composite resins activated the antioxidant system in saliva. However, further studies are now needed to confirm our findings and to permit a definitive conclusion. PMID:26321839

  15. Uric acid enhances the antitumor immunity of dendritic cell-based vaccine

    PubMed Central

    Wang, Yihan; Ma, Xuelei; Su, Chao; Peng, Bin; Du, Jing; Jia, Hongyuan; Luo, Min; Fang, Chunju; Wei, Yuquan

    2015-01-01

    Uric acid (UA) released from dying cells has been recognized by the immune system as a danger signal. In response to UA, dendritic cells (DC) in the immune system mature and enhance the T cell response to foreign antigens. It is conceivable that the antitumor immunity of a tumor vaccine could be promoted by the administration of UA. To test this concept, we applied UA as an adjuvant to a DC-based vaccine, and discovered that the administration of UA as an adjuvant significantly enhanced the ability of the tumor lysate-pulsed DC vaccine in delaying the tumor growth. The antitumor activity was achieved with adoptively transferred lymphocytes, and both CD8+ T cells and NK cells were required to achieve effective immunity. This resulted in an increased accumulation of activated CD8+ T cells and an elevated production of IFN-?. Collectively, our study shows that the administration of UA enhances the antitumor activity of tumor lysate-pulsed DC vaccine, thus providing the preclinical rationale for the application of UA in DC-based vaccine strategies. PMID:26553557

  16. Salivary concentrations of urea released from a chewing gum containing urea and how these affect the urea content of gel-stabilized plaques and their pH after exposure to sucrose.

    PubMed

    Dawes, C; Dibdin, G H

    2001-01-01

    The objectives were to: (1) determine the salivary concentrations of urea during 20 min chewing of a sugar-free gum containing 30 mg of urea; (2) measure the degree to which this urea would diffuse into a gel-stabilized plaque; (3) study the effect of the urea on the fall and subsequent rise in pH (Stephan curve) on exposure to 10% sucrose for 1 min; (4) model the measurements 2 and 3 mathematically. In point 1, the salivary urea concentration of the 12 subjects peaked at 47 mmol/l in the first 2 min of gum chewing, falling within 15 min to the unstimulated salivary concentration of 3.4 mmol/l. Recovery of urea from the saliva averaged 81.5%. 'Plaques' of 1% agarose or 67% dead bacteria in agarose accumulated urea from the saliva roughly as expected, whereas those plaques containing 8% live and 59% dead Streptococcus vestibularis showed negligible accumulation. Computer modelling showed this difference to be due to urease of live bacteria breaking down the urea as rapidly as it entered the plaque. Simulation of the effect of gum chewing subsequent to initiation of a Stephan curve in the latter type of plaque showed a rapid rise in pH but then a fall again on return to unstimulated conditions. This fall had not been seen in previous studies, with Streptococcus oralis, nor was it predicted by the computer modelling. Neither experimental simulation nor computer modelling suggested that chewing urea-containing gum before exposure to sucrose would have any effect on a subsequent Stephan curve. Thus chewing gum is only likely to inhibit caries when it is chewed after consumption of fermentable carbohydrate, rather than before. PMID:11641570

  17. 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).

  18. Folate Deficiency, Hyperhomocysteinemia, Low Urinary Creatinine, and Hypomethylation of Leukocyte DNA Are Risk Factors for Arsenic-Induced Skin Lesions

    PubMed Central

    Pilsner, J. Richard; Liu, Xinhua; Ahsan, Habibul; Ilievski, Vesna; Slavkovich, Vesna; Levy, Diane; Factor-Litvak, Pam; Graziano, Joseph H.; Gamble, Mary V.

    2009-01-01

    Background Arsenic methylation relies on folate-dependent one-carbon metabolism and facilitates urinary As elimination. Clinical manifestations of As toxicity vary considerably among individuals and populations, and poor methylation capacity is thought to confer greater susceptibility. Objective After determining that folate deficiency, hyperhomocysteinemia, and low urinary creatinine are associated with reduced As methylation, and that As exposure is associated with increased genomic methylation of leukocyte DNA, we asked whether these factors are associated with As-induced skin lesion risk among Bangladeshi adults. Methods We conducted a nested case–control study of 274 cases who developed lesions 2 years after recruitment, and 274 controls matched to cases for sex, age, and water As. Results The odds ratios and 95% confidence intervals (CIs) for development of skin lesions for participants who had low folate (< 9 nmol/L), hyperhomocysteinemia (men, > 11.4 ?mol/L; women, > 10.4 ?mol/L), or hypomethylated leukocyte DNA at recruitment (< median) were 1.8 (95% CI, 1.1–2.9), 1.7 (95% CI, 1.1–2.6), and 1.8 (95% CI, 1.2–2.8), respectively. Compared with the subjects in the first quartile, those in the third and fourth quartiles for urinary creatinine had a 0.4-fold decrease in the odds of skin lesions (p < 0.01). Conclusions These results suggest that folate deficiency, hyperhomocysteinemia, and low urinary creatinine, each associated with decreased As methylation, are risk factors for As-induced skin lesions. The increased DNA methylation associated with As exposure previously observed, and confirmed among controls in this study, may be an adaptive change because hypomethylation of leukocyte DNA is associated with increased risk for skin lesions. PMID:19270796

  19. Metabolic danger signals, uric acid and ATP, mediate inflammatory cross-talk between hepatocytes and immune cells in alcoholic liver disease.

    PubMed

    Petrasek, Jan; Iracheta-Vellve, Arvin; Saha, Banishree; Satishchandran, Abhishek; Kodys, Karen; Fitzgerald, Katherine A; Kurt-Jones, Evelyn A; Szabo, Gyongyi

    2015-08-01

    Inflammation defines the progression of ALD from reversible to advanced stages. Translocation of bacterial LPS to the liver from the gut is necessary for alcohol-induced liver inflammation. However, it is not known whether endogenous, metabolic danger signals are required for inflammation in ALD. Uric acid and ATP, 2 major proinflammatory danger signals, were evaluated in the serum of human volunteers exposed to a single dose of ethanol or in supernatants of primary human hepatocytes exposed to ethanol. In vitro studies were used to evaluate the role of uric acid and ATP in inflammatory cross-talk between hepatocytes and immune cells. The significance of signaling downstream of uric acid and ATP in the liver was evaluated in NLRP3-deficient mice fed a Lieber-DeCarli ethanol diet. Exposure of healthy human volunteers to a single dose of ethanol resulted in increased serum levels of uric acid and ATP. In vitro, we identified hepatocytes as a significant source of these endogenous inflammatory signals. Uric acid and ATP mediated a paracrine inflammatory cross-talk between damaged hepatocytes and immune cells and significantly increased the expression of LPS-inducible cytokines, IL-1? and TNF-?, by immune cells. Deficiency of NLRP3, a ligand-sensing component of the inflammasome recognizing uric acid and ATP, prevented the development of alcohol-induced liver inflammation in mice and significantly ameliorated liver damage and steatosis. Endogenous metabolic danger signals, uric acid, and ATP are involved in inflammatory cross-talk between hepatocytes and immune cells and play a crucial role in alcohol-induced liver inflammation. PMID:25934928

  20. A clinical study of /sup 99m/Tc dimercaptosuccinic acid uptake in obstructed kidneys: comparison with the creatinine clearance

    SciTech Connect

    De Maeyer, P.; Simons, M.; Oosterlinck, W.; De Sy, W.A.

    1982-07-01

    We studied 17 hydronephrotic kidneys owing to stenosis of the pyeloureteral junction. Preoperative uptake of /sup 99m/Tc dimercaptosuccinic acid was compared to early postoperative unilateral creatinine clearance, measured by urine collection from the nephrostomy tube. An excellent correlation was found. Therefore, uptake of /sup 99m/Tc dimercaptosuccinic acid represents a reliable parameter of renal function even in the presence of severe urinary tract obstruction. However, /sup 99m/Tc dimercaptosuccinic acid uptake should be measured more than 24 hours after injection of the tracer.

  1. [Rate of controlled-release urea pervasion through membrane determined by ultraviolet spectrophotometry].

    PubMed

    Zuo, Xiu-jin; Wang, Zhen-xin; Dai, Xiao-min; Zhou, Yi; Ma, Xiao-jun

    2006-06-01

    Application of controlled-release nitrogenous fertilizers can improve the efficiency of fertilizers and reduce the environmental pollution. Controlled-release urea (coated urea) is one of the controlled-release nitrogenous fertilizers developed quickly in the recent years. The rate of controlled-release urea pervasion through membrane is the most important index of the capacity of controlled release. There is a maximum absorption at lambda=426 nm with complex in acidic solution, using p-dimethylaminozenzaldehyde as color reagent, and the absorbance exhibits a linear reponses to the urea concentration over the range of 7.5-210 microg x mL(-1). The method for determining the rate of controlled-release urea pervasion through membrane was realized through determining the content of urea in the liquor, the recovery efficiency of the method is 96.1%-103.9%. PMID:16961255

  2. 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 90 days) 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 173 L/kg VS, 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

  3. 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.

  4. 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

  5. A current perspective on the compensatory effects of urea and methylamine on protein stability and function.

    PubMed

    Rahman, Safikur; Warepam, Marina; Singh, Laishram R; Dar, Tanveer Ali

    2015-11-01

    Urea is a strong denaturant and inhibits many enzymes but is accumulated intracellularly at very high concentrations (up to 3-4 M) in mammalian kidney and in many marine fishes. It is known that the harmful effects of urea on the macromolecular structure and function is offset by the accumulation of an osmolytic agent called methylamine. Intracellular concentration of urea to methylamines falls in the ratio of 2:1 to 3:2 (molar ratio). At this ratio, the thermodynamic effects of urea and methylamines on protein stability and function are believed to be algebraically additive. The mechanism of urea-methylamine counteraction has been widely investigated on various approaches including, thermodynamic, structural and functional aspects. Recent advances have also revealed atomic level insights of counteraction and various molecular dynamic simulation studies have yielded significant molecular level informations on the interaction between urea and methylamines with proteins. It is worthwhile that urea-methylamine system not only plays pivotal role for the survival and functioning of the renal medullary cells but also is a key osmoregulatory component of the marine elasmobranchs, holocephalans and coelacanths. Therefore, it is important to combine all discoveries and discuss the developments in context to physiology of the mammalian kidney and adaptation of the marine organisms. In this article we have for the first time reviewed all major developments on urea-counteraction systems to date. We have also discussed about other additional urea-counteraction systems discovered so far including urea-NaCl, urea-myoinsoitol and urea-molecular chaperone systems. Insights for the possible future research have also been highlighted. PMID:26095775

  6. Thiomonas sp. CB2 is able to degrade urea and promote toxic metal precipitation in acid mine drainage waters supplemented with urea.

    PubMed

    Farasin, Julien; Andres, Jérémy; Casiot, Corinne; Barbe, Valérie; Faerber, Jacques; Halter, David; Heintz, Dimitri; Koechler, Sandrine; Ličvremont, Didier; Lugan, Raphael; Marchal, Marie; Plewniak, Frédéric; Seby, Fabienne; Bertin, Philippe N; Arsčne-Ploetze, Florence

    2015-01-01

    The acid mine drainage (AMD) in Carnoulčs (France) is characterized by the presence of toxic metals such as arsenic. Several bacterial strains belonging to the Thiomonas genus, which were isolated from this AMD, are able to withstand these conditions. Their genomes carry several genomic islands (GEIs), which are known to be potentially advantageous in some particular ecological niches. This study focused on the role of the "urea island" present in the Thiomonas CB2 strain, which carry the genes involved in urea degradation processes. First, genomic comparisons showed that the genome of Thiomonas sp. CB2, which is able to degrade urea, contains a urea genomic island which is incomplete in the genome of other strains showing no urease activity. The urease activity of Thiomonas sp. CB2 enabled this bacterium to maintain a neutral pH in cell cultures in vitro and prevented the occurrence of cell death during the growth of the bacterium in a chemically defined medium. In AMD water supplemented with urea, the degradation of urea promotes iron, aluminum and arsenic precipitation. Our data show that ureC was expressed in situ, which suggests that the ability to degrade urea may be expressed in some Thiomonas strains in AMD, and that this urease activity may contribute to their survival in contaminated environments. PMID:26441922

  7. Thiomonas sp. CB2 is able to degrade urea and promote toxic metal precipitation in acid mine drainage waters supplemented with urea

    PubMed Central

    Farasin, Julien; Andres, Jérémy; Casiot, Corinne; Barbe, Valérie; Faerber, Jacques; Halter, David; Heintz, Dimitri; Koechler, Sandrine; Ličvremont, Didier; Lugan, Raphael; Marchal, Marie; Plewniak, Frédéric; Seby, Fabienne; Bertin, Philippe N.; Arsčne-Ploetze, Florence

    2015-01-01

    The acid mine drainage (AMD) in Carnoulčs (France) is characterized by the presence of toxic metals such as arsenic. Several bacterial strains belonging to the Thiomonas genus, which were isolated from this AMD, are able to withstand these conditions. Their genomes carry several genomic islands (GEIs), which are known to be potentially advantageous in some particular ecological niches. This study focused on the role of the “urea island” present in the Thiomonas CB2 strain, which carry the genes involved in urea degradation processes. First, genomic comparisons showed that the genome of Thiomonas sp. CB2, which is able to degrade urea, contains a urea genomic island which is incomplete in the genome of other strains showing no urease activity. The urease activity of Thiomonas sp. CB2 enabled this bacterium to maintain a neutral pH in cell cultures in vitro and prevented the occurrence of cell death during the growth of the bacterium in a chemically defined medium. In AMD water supplemented with urea, the degradation of urea promotes iron, aluminum and arsenic precipitation. Our data show that ureC was expressed in situ, which suggests that the ability to degrade urea may be expressed in some Thiomonas strains in AMD, and that this urease activity may contribute to their survival in contaminated environments. PMID:26441922

  8. A novel small-molecule thienoquinolin urea transporter inhibitor acts as a potential diuretic.

    PubMed

    Li, Fei; Lei, Tianluo; Zhu, Juanjuan; Wang, Weiling; Sun, Yi; Chen, Jihui; Dong, Zixun; Zhou, Hong; Yang, Baoxue

    2013-06-01

    Urea transporters (UTs) are a family of membrane channel proteins that are specifically permeable to urea and play an important role in intrarenal urea recycling and in urine concentration. Using an erythrocyte osmotic lysis assay, we screened a small-molecule library for inhibitors of UT-facilitated urea transport. A novel class of thienoquinolin UT-B inhibitors were identified, of which PU-14 had potent inhibition activity on human, rabbit, rat, and mouse UT-B. The half-maximal inhibitory concentration of PU-14 on rat UT-B-mediated urea transport was ?0.8 ?mol/l, and it did not affect urea transport in mouse erythrocytes lacking UT-B but inhibited UT-A-type urea transporters, with 36% inhibition at 4 ?mol/l. PU-14 showed no significant cellular toxicity at concentrations up to its solubility limit of 80 ?mol/l. Subcutaneous delivery of PU-14 (at 12.5, 50, and 100 mg/kg) to rats caused an increase of urine output and a decrease of the urine urea concentration and subsequent osmolality without electrolyte disturbances and liver or renal damages. This suggests that PU-14 has a diuretic effect by urea-selective diuresis. Thus, PU-14 or its analogs might be developed as a new diuretic to increase renal fluid clearance in diseases associated with water retention without causing electrolyte imbalance. PU-14 may establish 'chemical knockout' animal models to study the physiological functions of UTs. PMID:23486518

  9. Functional characterization of Actinobacillus pleuropneumoniae urea transport protein, ApUT.

    PubMed

    Godara, Geeta; Smith, Craig; Bosse, Janine; Zeidel, Mark; Mathai, John

    2009-04-01

    Urea transporters (UTs) effect rapid flux of urea across biological membranes. In the mammalian kidney, UT activity is essential for effective urine concentration. In bacteria, UT-mediated urea uptake permits intracellular urease to degrade urea to ammonia and CO(2), a process that either buffers acid loads or provides nutrient nitrogen. We have characterized the urea transport channel protein ApUT from Actinobacillus pleuropneumoniae. Kinetic analysis of bacterial inside-out membranes enriched in ApUT showed approximately 28-fold increase in urea permeability (3.3 +/- 0.4 x 10(-4) cm/s) compared with control vesicles (0.11 +/- 0.02 x 10(-4) cm/s). In addition to urea, ApUT also conducts water. Urea and water transport across the channel was phloretin and mercury inhibitable, and the site of inhibition may be located on the cytoplasmic side of the protein. Glycerol and urea analogs, such as methylamine, dimethylurea, formamide, acetamide, methylurea, propanamide, and ethylamine did not permeate across ApUT. PMID:19144751

  10. Escalating worldwide use of urea a global change contributing to coastal eutrophication

    E-print Network

    Seitzinger, Sybil

    Escalating worldwide use of urea ­ a global change contributing to coastal eutrophication PATRICIA: Agricultural runoff, Eutrophication, Global change, Harmful algal blooms, Nitrogen fertilizer, Organic nitrogen

  11. Health effects of urea formaldehyde foam insulation: evidence of causation.

    PubMed Central

    Norman, G R; Newhouse, M T

    1986-01-01

    Studies of health effects of urea formaldehyde foam insulation (UFFI) were critically reviewed by means of accepted rules for evidence of causation. Three categories of health effects were examined: reported symptoms, primarily of the upper respiratory tract, lower respiratory tract disease and cancer. Most of the studies purporting to demonstrate health effects of UFFI failed to meet minimal methodologic criteria for evidence of causation. Evidence from the adequate studies provides little support for the hypothesis of a causative role of UFFI in health problems. PMID:3512066

  12. Determining the amounts of urea and glucose in urine of patients with renal complications from diabetes mellitus and hypertension by near-infrared Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Bispo, Jeyse A. M.; Silveira, Landulfo; Vieira, Elzo E. d. S.; Fernandes, Adriana B.

    2013-02-01

    Diabetes mellitus and hypertension diseases are frequently found in the same patient, which if untreated predispose to atherosclerotic and kidney diseases. The objective of this study was to identify potential biomarkers in the urine of diabetic and hypertensive patients through dispersive near-infrared Raman spectroscopy. Urine samples were collected from patients with diabetes and hypertension but no complications (LG), high degree of complications (HG), and control ones: one fraction was submitted to biochemical tests and another one was stored frozen (-20°C) until spectral analysis. Samples were warmed up and placed in an aluminum sample holder for Raman spectra collection using a dispersive spectrometer (830 nm wavelength, 300 mW laser power and 20 s exposure time). Spectra were then submitted to Principal Components Analysis. The PCA loading vectors 1 and 3 revealed spectral features of urea/creatinine and glucose, respectively; the PCA scores showed that patients with diabetes/hypertension (LG and HG) had higher amount of glucose in the urine compared to the normal group (p < 0.05), which can bring serious consequences to patients. Also, the PCA scores showed that the amount of urea decreased in the groups with diabetes/hypertension (p < 0.05), which generates the same concern as it is a marker that has a strong importance in the metabolic changes induced by such diseases. These results, applied to the analysis of urine of patients with diabetes/hypertension, can lead to early diagnostic information of complications and a possible disease prognosis in the patients where no complications from diabetes and hypertension were found.

  13. Urinary hydroxyproline to creatinine ratio as a biological effect marker for exposure to NO 2 and tobacco smoke

    NASA Astrophysics Data System (ADS)

    Yanagisawa, Yukio; Nishimura, Hajime; Matsuki, Hideaki; Osaka, Fumio; Kasuga, Hitoshi

    In order to study the relationship between NO 2 exposure and effects, we monitored personal NO 2 exposures and the hydroxyproline to creatinine ratio in urine of about 800 women in two communities near Tokyo. Monitoring was conducted during two seasons, winter and summer 1982. The hydroxyproline to creatinine ratio (HOP:C) was determined from urine samples collected in the early morning. Daily average personal NO 2 exposures (ENO 2) were measured by using a filter badge. In both seasons, HOP:C was found to have significant correlation with ENO 2 and active and passive smoking. In addition, subjects living near major roads had significantly higher HOP:C levels in the summer compared with those living far from them. We hypothesize that these higher HOP:C levels in the summer were due to higher air exchange rates resulting in infiltration of automobile exhaust into homes. ENO 2, however, did not correlate with either the distance of the subject's house from major roads or with the amount of smoking. Stepwise multiple regression analysis revealed that HOP:C could be predicted by personal NO 2 exposures and smoking variables with a high level of confidence.

  14. Personal exposure and health effect relationship for NO2 with urinary hydroxyproline to creatinine ratio as indicator

    SciTech Connect

    Yanagisawa, Y.; Nishimura, H.; Matsuki, H.; Osaka, F.; Kasuga, H.

    1986-01-01

    Establishment of an exposure-effect relationship was attempted between personal nitrogen dioxide (NO/sub 2/) exposure and urinary hydroxyproline to creatinine ratio of approximately 800 adult women, who were mothers of primary schoolchildren living in two communities around Tokyo. Daily average of the personal NO/sub 2/ exposure (ENO/sub 2/) was measured during wintertime by a newly developed personal monitor exposed for 24 hours. The hydroxyproline to creatinine ratio (HOP:C) in the urine sample collected early in the morning of the day for ENO/sub 2/ measurement was used as a biochemical indicator of the health effect of NO/sub 2/ exposure. The HOP:C was found to have significant correlation with ENO/sub 2/ and number of cigarettes smoked actively and passively. ENO/sub 2/, however, had no correlation with the intensity of the smoking levels; they might affect HOP:C independently. Stepwise multiple regression analysis revealed that HOP:C could be predicted by ENO/sub 2/ and smoking habits at a high confidence level. The regression analysis of the active smokers group indicated that a few cigarettes was enough to increase the HOP:C, while in the case of passive smoking, HOP:C increased proportionally to the number of cigarettes.

  15. 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. PMID:26097422

  16. Urinary output and fractional excretion of sodium and urea as indicators of transient versus intrinsic acute kidney injury during early sepsis

    PubMed Central

    2013-01-01

    Introduction The pathophysiology of acute kidney injury (AKI) in sepsis is ill defined. We investigated parameters associated with low glomerular filtration, and their predictive value to discriminate transient from intrinsic septic AKI. Methods In 107 sepsis patients, AKI was defined by the Risk, Injury, Failure, Loss of Kidney Function, End-stage renal disease (RIFLE) urinary output or serum creatinine criterion, or both. Transient AKI (TAKI) versus intrinsic AKI was defined as RIFLE R, I, or F on the first day evolving to no AKI or not, respectively, over the following 5 days. Fractional excretion of sodium (FENa), urea (FEUrea), and NGAL (FENGAL) at admission (d0t0), 4 (d0t4), and 24 hours (d1) was determined. Results Including versus not including the urinary-output criterion of RIFLE increased AKI from 43% to 64.5%. Median uNGAL levels and FENGAL were lower in no AKI versus transient AKI when AKI was defined based on creatinine (P = 0.002 and P = 0.04, respectively), but not when based on urinary output (P = 0.9 and P = 0.49, respectively). FENa < 1% and FEUrea <35% was present in 77.3% and 63.2% of patients. Urinary NGAL was higher (P < 0.001) in those with high versus low fractional sodium excretion, but this was only in patients with transient or intrinsic AKI (P < 0.001 in subgroups), and not in patients without AKI. The negative predictive value for either intrinsic AKI or not restoring diuresis in patients with FENa > 0.36% and FEUrea > 31.5% was 92% and 94.5% respectively. Conclusions A low FENa and FEUrea is highly prevalent in the first hours of sepsis. In sepsis, oliguria is an earlier sign of impending AKI than increase in serum creatinine. A combination of a high FENa and a low FEUrea is associated with intrinsic AKI, whereas a combined high FENa and FEUrea is strongly predictive of transient AKI. PMID:24119730

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

    NASA Astrophysics Data System (ADS)

    Palanisamy, Sivakumar

    2014-12-01

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

  18. Prognostic Role of Serum Levels of Uric Acid in Amyotrophic Lateral Sclerosis

    PubMed Central

    Oh, Seong-il; Baek, Soojeong; Park, Jin-Seok; Piao, Liying; Oh, Ki-Wook

    2015-01-01

    Background and Purpose It has been suggested that oxidative stress is one of the pathomechanisms underlying amyotrophic lateral sclerosis (ALS), and thus antioxidants such as uric acid (UA) that could reduce oxidative stress might be beneficial in the prevention or treatment of this disease. The objective of this study was to prospectively investigate serum UA levels in Korean ALS patients and to relate them to disease progression. Methods ALS patients and healthy controls who were individually well-matched for sex, age, and body mass index (BMI) underwent blood testing for serum UA levels, and analyzed whether UA levels were correlated with the disease status of the patients, as defined by the ALS Functional Rating Scale-Revised (ALSFRS-R). Results The study included 136 ALS patients and 136 matched controls. The UA level was lower in the ALS patients (4.50±1.17 mg/dL, mean±SD) than in the controls (5.51±1.22 mg/dL; p<0.001). Among the ALS patients, the level of UA acid was inversely correlated with the rate of disease progression (decrease in ALSFRS-R score). Kaplan-Meier analysis revealed that a better survival rate was more strongly correlated with top-tertile levels of serum UA than with bottom-tertile levels (log-rank test: p=0.035). Conclusions ALS patients had lower serum UA levels than did healthy individuals. UA levels in ALS were negatively correlated with the rate of disease progression and positively associated with survival, suggesting that UA levels contribute to the progression of ALS. UA levels could be considered a biomarker of disease progression in the early phase in ALS patients. PMID:26424237

  19. Association between colon diverticula and hemoglobin, triglyceride and uric acid levels

    PubMed Central

    TOMIZAWA, MINORU; SHINOZAKI, FUMINOBU; HASEGAWA, RUMIKO; SHIRAI, YOSHINORI; MOTOYOSHI, YASUFUMI; SUGIYAMA, TAKAO; YAMAMOTO, SHIGENORI; ISHIGE, NAOKI

    2015-01-01

    Colon diverticula cause bleeding and acute diverticulitis. The present study analyzed laboratory test variables, aiming to predict the presence of diverticula. Patient records from between April 2011 and March 2014 were analyzed retrospectively (1,520 patients) and a one-way analysis of variance was performed to analyze the association between the presence of diverticula and each variable. A ?2 test was then used to assess the correlation between the prevalence of diverticula and the percentage of patients with uric acid (UA) levels ?5.1 mg/dl. A receiver operating characteristic (ROC) analysis was performed to determine the threshold values required to predict the presence of diverticula. Hemoglobin (Hb) levels were lower in patients with diverticula than in those without diverticula (P=0.0027), and compared with patients without diverticula, UA and triglyceride (TG) levels were higher in patients with diverticula (P=0.0066 and P=0.0136, respectively). The patients were divided into two groups, as follows: Patients with UA levels ?5.1 mg/dl (the median value) and those with UA levels <5.1 mg/dl. The prevalence of diverticula was significantly higher in patients with UA levels ?5.1 mg/dl than in those with UA levels <5.1 mg/dl (P=0.0004). ROC analysis demonstrated that the threshold values of Hb, TG and UA were 12,400, 146 and 5.1 mg/dl, respectively. The sensitivity of the Hb and UA levels at the threshold values was 76.5 and 71.0%, respectively. The prevalence of diverticula was associated with low Hb levels, and high TG and UA levels. PMID:26668609

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

    PubMed Central

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

    2014-01-01

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

  1. Administration of Uric Acid in the Emergency Treatment of Acute Ischemic Stroke.

    PubMed

    Llull, Laura; Amaro, Sergio; Chamorro, Ángel

    2016-01-01

    Oxidative stress is one of the main mechanisms implicated in the pathophysiology of inflammatory and neurodegenerative diseases of the central nervous system (CNS). Uric acid (UA) is the end product of purine catabolism in humans, and it is the main endogenous antioxidant in blood. Low circulating UA levels have been associated with an increased prevalence and worse clinical course of several neurodegenerative and inflammatory diseases of the CNS, including Parkinson's disease and multiple sclerosis. Moreover, the exogenous administration of UA exerts robust neuroprotective properties in experimental models of CNS disease, including brain ischemia, spinal cord injury, meningitis, and experimental allergic encephalitis. In experimental brain ischemia, exogenous UA and the thrombolytic agent alteplase exert additive neuroprotective effects when administered in combination. UA is rapidly consumed following acute ischemic stroke, and higher UA levels at stroke admission are associated with a better outcome and reduced infarct growth at follow-up. A recent phase II trial demonstrated that the combined intravenous administration of UA and alteplase is safe and prevents an early decrease of circulating UA levels in acute ischemic stroke patients. Moreover, UA prevents the increase in the circulating levels of the lipid peroxidation marker malondialdehyde and of active matrix metalloproteinase (MMP) 9, a marker of blood-brain barrier disruption. The moderately sized URICOICTUS phase 2b trial showed that the addition of UA to thrombolytic therapy resulted in a 6 % absolute increase in the rate of excellent outcome at 90 days compared to placebo. The trial also showed that UA administration resulted in a significant increment of excellent outcome in patients with pretreatment hyperglycemia, in females and in patients with moderate strokes. Overall, the encouraging neuroprotective effects of UA therapy in acute ischemic stroke warrants further investigation in adequately powered clinical trials. PMID:26711273

  2. FITC-tagged macromolecule-based alginate microspheres for urea sensoring

    NASA Astrophysics Data System (ADS)

    Joshi, Abhijeet; Chaudhari, Rashmi; Srivastava, Rohit

    2014-04-01

    Urea is an important biomarker for identification of kidney diseases. Early urea detection using a specific and sensitive technique can significantly reduce the mortality of patients. The research aims at developing fluorescence-based FITCmediated pH and urea measurement. A system containing FITC-dextran in alginate microspheres was developed using air-driven atomization. pH/Urea biosensor was characterized using optical microscopy, SEM, and CLSM. Urea biosensing studies were performed by exposing different standard solutions of pH and urea standard solutions using fluorescence spectroscopy (?ex=488 nm and ?em=520 nm). FITC-dextran was entrapped using an encapsulation unit and alginate microspheres were formed. The microspheres were found to be uniform and spherical in nature with sizes (50±10?). FITC-dextran was found to be uniformly distributed in the alginate microspheres as per the CLSM scans. Urea biosensing studies indicate that a linear correlation was observed with increasing urea concentrations. The said microspheres can be used to detect changes in pH from 4-8 units owing to its linear response in this range. FITC dextran loaded alginate microspheres showed an improved range of detection upto 7 mM in comparison to 1.5 mM when in solution phase in a study with urea concentrations from 0-50 mM. The pH and urea detection was accurate to an extent of interday variation of 5%. FITC-dextran loaded alginate microspheres show a great potential for usage as a pH and urea biosensor for early detection of kidney diseases.

  3. 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

  4. Nitrogen leaching from Douglas-fir forests after urea fertilization.

    PubMed

    Flint, Cynthia M; Harrison, Rob B; Strahm, Brian D; Adams, A B

    2008-01-01

    Leaching of nitrogen (N) after forest fertilization has the potential to pollute ground and surface water. The purpose of this study was to quantify N leaching through the primary rooting zone of N-limited Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] forests the year after fertilization (224 kg N ha(-1) as urea) and to calculate changes in the N pools of the overstory trees, understory vegetation, and soil. At six sites on production forests in the Hood Canal watershed, Washington, tension lysimeters and estimates of the soil water flux were used to quantify the mobilization and leaching of NO(3)-N, NH(4)-N, and dissolved organic nitrogen below the observed rooting depth. Soil and vegetation samples were collected before fertilization and 1 and 6 mo after fertilization. In the year after fertilization, the total leaching beyond the primary rooting zone in excess of control plots was 4.2 kg N ha(-1) (p = 0.03), which was equal to 2% of the total N applied. The peak NO(3)-N concentration that leached beyond the rooting zone of fertilized plots was 0.2 mg NO(3)-N L(-1). Six months after fertilization, 26% of the applied N was accounted for in the overstory, and 27% was accounted for in the O+A horizon of the soil. The results of this study indicate that forest fertilization can lead to small N leaching fluxes out of the primary rooting zone during the first year after urea application. PMID:18689739

  5. Voltamperometric Discrimination of Urea and Melamine Adulterated Skimmed Milk Powder

    PubMed Central

    Hilding-Ohlsson, Astrid; Fauerbach, Jonathan A.; Sacco, Natalia J.; Bonetto, M. Celina; Cortón, Eduardo

    2012-01-01

    Nitrogen compounds like urea and melamine are known to be commonly used for milk adulteration resulting in undesired intoxication; a well-known example is the Chinese episode occurred in 2008. The development of a rapid, reliable and economic test is of relevance in order to improve adulterated milk identification. Cyclic voltammetry studies using an Au working electrode were performed on adulterated and non-adulterated milk samples from different independent manufacturers. Voltammetric data and their first derivative were subjected to functional principal component analysis (f-PCA) and correctly classified by the KNN classifier. The adulterated and non-adulterated milk samples showed significant differences. Best results of prediction were obtained with first derivative data. Detection limits in milk samples adulterated with 1% of its total nitrogen derived from melamine or urea were as low as 85.0 mg·L?1 and 121.4 mg·L?1, respectively. We present this method as a fast and robust screening method for milk adulteration analysis and prevention of food intoxication. PMID:23112709

  6. PLATELET ADHESION TO POLYURETHANE UREA UNDER PULSATILE FLOW CONDITIONS

    PubMed Central

    Navitsky, Michael A.; Taylor, Joshua O.; Smith, Alexander B.; Slattery, Margaret J.; Deutsch, Steven; Siedlecki, Christopher A.; Manning, Keefe B.

    2014-01-01

    Platelet adhesion to a polyurethane urea surface is a precursor to thrombus formation within blood-contacting cardiovascular devices, and platelets have been found to adhere strongly to polyurethane surfaces below a shear rate of approximately 500 s?1. The aim of the current work is to determine platelet adhesion properties to the polyurethane urea surface as a function of time varying shear exposure. A rotating disk system is used to study the influence of steady and pulsatile flow conditions (e.g. cardiac inflow and sawtooth waveforms) for platelet adhesion to the biomaterial surface. All experiments retain the same root mean square angular rotation velocity (29.63 rad/s) and waveform period. The disk is rotated in platelet rich bovine plasma for two hours with adhesion quantified by confocal microscopy measurements of immunofluorescently labeled bovine platelets. Platelet adhesion under pulsating flow is found to exponentially decay with increasing shear rate. Adhesion levels are found to depend upon peak platelet flux and shear rate regardless of rotational waveform. In combination with flow measurements, these results may be useful for predicting regions susceptible to thrombus formation within ventricular assist devices. PMID:24721222

  7. Soybean oil-isosorbide-based waterborne polyurethane-urea dispersions.

    PubMed

    Xia, Ying; Larock, Richard C

    2011-03-21

    A series of soybean oil-based amide diol-isosorbide waterborne polyurethane-urea (PUU) dispersions have been successfully prepared, with amounts of isosorbide ranging from 0 to 20?wt?% of the total diol content. The thermal and mechanical properties of the resulting PUU films have been characterized by dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, and mechanical testing. The results reveal that the glass transition temperature is increased with increased amounts of isosorbide, and the mechanical properties are improved significantly with the incorporation of isosorbide. For example, the Young's modulus increases from 2.3 to 63?MPa and the ultimate tensile strength increases from 0.7 to 8.2?MPa when the isosorbide amount is increased from 0 to 20?wt?%. The thermal stability decreases slightly with the incorporation of isosorbide. This work provides a new way of utilizing biorenewable materials, such as isosorbide and a soybean oil-based amide diol, for the preparation of high-performance polyurethane-urea coatings. PMID:21259447

  8. Efficient voltammetric discrimination of free bilirubin from uric acid and ascorbic acid by a CVD nanographite-based microelectrode.

    PubMed

    Taurino, Irene; Van Hoof, Viviane; Magrez, Arnaud; Forró, László; De Micheli, Giovanni; Carrara, Sandro

    2014-12-01

    We report a novel electrochemical sensor based on nanographite grown on platinum microelectrodes for the determination of bilirubin in the presence of normal concentrations of albumin. The albumin is a protein with an intrinsic ability to bind the bilirubin therefore reducing the concentration of the free electroactive metabolite in human fluids. In addition, the proposed device permits the discrimination of free bilirubin from two interferents, uric acid and ascorbic acid, by the separation of their oxidation peaks in voltammetry. Preliminary measurements in human serum prove that the proposed nanostructured platform can be used to detect bilirubin. PMID:25159430

  9. Diabetic Nephropathy and CKD—Analysis of Individual Patient Serum Creatinine Trajectories: A Forgotten Diagnostic Methodology for Diabetic CKD Prognostication and Prediction

    PubMed Central

    Onuigbo, Macaulay Amechi Chukwukadibia; Agbasi, Nneoma

    2015-01-01

    Creatinine is produced in muscle metabolism as the end-product of creatine phosphate and is subsequently excreted principally by way of the kidneys, predominantly by glomerular filtration. Blood creatinine assays constitute the most common clinically relevant measure of renal function. The use of individual patient-level real-time serum creatinine trajectories provides a very attractive and tantalizing methodology in nephrology practice. Topics covered in this review include acute kidney injury (AKI) with its multifarious rainbow spectrum of renal outcomes; the stimulating vicissitudes of the diverse patterns of chronic kidney disease (CKD) to end-stage renal disease (ESRD) progression, including the syndrome of rapid onset end stage renal disease (SORO-ESRD); the syndrome of late onset renal failure from angiotensin blockade (LORFFAB); and post-operative AKI linked with the role of intra-operative hypotension in patients with diabetes mellitus and suspected diabetic nephropathy with CKD. We conclude that the study of individual patient-level serum creatinine trajectories, albeit a neglected and forgotten diagnostic methodology for diabetic CKD prognostication and prediction, is a most useful diagnostic tool, both in the short-term and in the long-term practice of nephrology. The analysis of serum creatinine trajectories, both in real time and retrospectively, indeed provides supplementary superior diagnostic and prognostic insights in the management of the nephrology patient. PMID:26239680

  10. Diabetic Nephropathy and CKD-Analysis of Individual Patient Serum Creatinine Trajectories: A Forgotten Diagnostic Methodology for Diabetic CKD Prognostication and Prediction.

    PubMed

    Onuigbo, Macaulay Amechi Chukwukadibia; Agbasi, Nneoma

    2015-01-01

    Creatinine is produced in muscle metabolism as the end-product of creatine phosphate and is subsequently excreted principally by way of the kidneys, predominantly by glomerular filtration. Blood creatinine assays constitute the most common clinically relevant measure of renal function. The use of individual patient-level real-time serum creatinine trajectories provides a very attractive and tantalizing methodology in nephrology practice. Topics covered in this review include acute kidney injury (AKI) with its multifarious rainbow spectrum of renal outcomes; the stimulating vicissitudes of the diverse patterns of chronic kidney disease (CKD) to end-stage renal disease (ESRD) progression, including the syndrome of rapid onset end stage renal disease (SORO-ESRD); the syndrome of late onset renal failure from angiotensin blockade (LORFFAB); and post-operative AKI linked with the role of intra-operative hypotension in patients with diabetes mellitus and suspected diabetic nephropathy with CKD. We conclude that the study of individual patient-level serum creatinine trajectories, albeit a neglected and forgotten diagnostic methodology for diabetic CKD prognostication and prediction, is a most useful diagnostic tool, both in the short-term and in the long-term practice of nephrology. The analysis of serum creatinine trajectories, both in real time and retrospectively, indeed provides supplementary superior diagnostic and prognostic insights in the management of the nephrology patient. PMID:26239680

  11. Enhancing the urea-N use efficiency in maize (Zea mays) cultivation on acid soils amended with zeolite and TSP.

    PubMed

    Ahmed, Osumanu H; Hussin, Aminuddin; Ahmad, Husni M H; Rahim, Anuar A; Majid, Nik Muhamad Abd

    2008-01-01

    Ammonia loss significantly reduces the urea-N use efficiency in crop production. Efforts to reduce this problem are mostly laboratory oriented. This paper reports the effects of urea amended with triple superphosphate (TSP) and zeolite (Clinoptilolite) on soil pH, nitrate, exchangeable ammonium, dry matter production, N uptake, fresh cob production, and urea-N uptake efficiency in maize (Zea mays) cultivation on an acid soil in actual field conditions. Urea-amended TSP and zeolite treatments and urea only (urea without additives) did not have long-term effect on soil pH and accumulation of soil exchangeable ammonium and nitrate. Treatments with higher amounts of TSP and zeolite significantly increased the dry matter (stem and leaf) production of Swan (test crop). All the treatments had no significant effect on urea-N concentration in the leaf and stem of the test crop. In terms of urea-N uptake in the leaf and stem tissues of Swan, only the treatment with the highest amount of TSP and zeolite significantly increased urea-N uptake in the leaf of the test crop. Irrespective of treatment, fresh cob production was statistically not different. However, all the treatments with additives improved urea-N uptake efficiency compared to urea without additives or amendment. This suggests that urea amended with TSP and zeolite has a potential of reducing ammonia loss from surface-applied urea. PMID:18454247

  12. 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 (...

  13. 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

  14. 78 FR 46571 - Solid Urea From the Russian Federation: Preliminary Results of Antidumping Duty Administrative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-01

    ...antidumping duty order on solid urea from the Russian Federation (Russia). The period of review (POR) is July 1, 2011, through...of administrative review for all shipments of solid urea from Russia entered, or withdrawn from warehouse, for consumption on...

  15. 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...review decisions for the pesticides propionic acid and salts, and urea sulfate and...decisions. The active ingredient propionic acid is a fungicide and...

  16. 40 CFR 418.30 - Applicability; description of the urea subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the urea subcategory. 418.30 Section 418.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory §...

  17. 40 CFR 418.30 - Applicability; description of the urea subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the urea subcategory. 418.30 Section 418.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory §...

  18. 40 CFR 418.30 - Applicability; description of the urea subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Applicability; description of the urea subcategory. 418.30 Section 418.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory §...

  19. 40 CFR 418.30 - Applicability; description of the urea subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Applicability; description of the urea subcategory. 418.30 Section 418.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory §...

  20. 40 CFR 418.30 - Applicability; description of the urea subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the urea subcategory. 418.30 Section 418.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory §...

  1. Urea and Ammonia Metabolism and the Control of Renal Nitrogen Excretion.

    PubMed

    Weiner, I David; Mitch, William E; Sands, Jeff M

    2015-08-01

    Renal nitrogen metabolism primarily involves urea and ammonia metabolism, and is essential to normal health. Urea is the largest circulating pool of nitrogen, excluding nitrogen in circulating proteins, and its production changes in parallel to the degradation of dietary and endogenous proteins. In addition to serving as a way to excrete nitrogen, urea transport, mediated through specific urea transport proteins, mediates a central role in the urine concentrating mechanism. Renal ammonia excretion, although often considered only in the context of acid-base homeostasis, accounts for approximately 10% of total renal nitrogen excretion under basal conditions, but can increase substantially in a variety of clinical conditions. Because renal ammonia metabolism requires intrarenal ammoniagenesis from glutamine, changes in factors regulating renal ammonia metabolism can have important effects on glutamine in addition to nitrogen balance. This review covers aspects of protein metabolism and the control of the two major molecules involved in renal nitrogen excretion: urea and ammonia. Both urea and ammonia transport can be altered by glucocorticoids and hypokalemia, two conditions that also affect protein metabolism. Clinical conditions associated with altered urine concentrating ability or water homeostasis can result in changes in urea excretion and urea transporters. Clinical conditions associated with altered ammonia excretion can have important effects on nitrogen balance. PMID:25078422

  2. 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

  3. 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

    ... amended (the Act). See Initiation of Five-Year (``Sunset'') Review, 75 FR 74685 (December 1, 2010); see also Solid Urea From Russia and Ukraine, 75 FR 74746 (December 1, 2010). \\1\\ On July 14, 1987, the... States within a reasonably foreseeable time. See Solid Urea From Russia and Ukraine, 76 FR...

  4. 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

  5. 40 CFR 721.9920 - Urea, (hexahydro-6-methyl-2-oxopyrimidinyl)-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Urea, (hexahydro-6-methyl-2... Specific Chemical Substances § 721.9920 Urea, (hexahydro-6-methyl-2-oxopyrimidinyl)-. (a) Chemical...-methyl-2oxopyrimidinyl)- (PMN P-89-303) is subject to reporting under this section for the...

  6. 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.

  7. Role of rumen butyrate in regulation of nitrogen utilization and urea nitrogen kinetics in growing sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Butyrate, a major rumen VFA, has been indirectly linked to enhancement of urea recycling based on increased expression of urea transporter (UT-B) in the rumen epithelia of steers fed a rumen butyrate-enhancing diet. Two studies were conducted to quantify the effect of elevated rumen butyrate concent...

  8. 40 CFR 721.10533 - Amine-modified urea-formaldehyde polymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... polymer (generic). 721.10533 Section 721.10533 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10533 Amine-modified urea-formaldehyde polymer (generic). (a) Chemical... as amine-modified urea-formaldehyde polymer (PMN P-12-182) is subject to reporting under this...

  9. 40 CFR 721.10533 - Amine-modified urea-formaldehyde polymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... polymer (generic). 721.10533 Section 721.10533 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10533 Amine-modified urea-formaldehyde polymer (generic). (a) Chemical... as amine-modified urea-formaldehyde polymer (PMN P-12-182) is subject to reporting under this...

  10. UREA PRODUCTION, RECYCLING AND EXCRETION IN FORAGE-FED BEEF STEERS.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two experiments with growing beef steers fed hays of warm season (gamagrass and switchgrass) or cool season (tall fescue) grasses showed a strong linear relationship between urea production by the animal and urinary urea excretion as functions of nitrogen (crude protein) intake. The nature of the r...

  11. Monolithic gelation of chitosan solutions via enzymatic hydrolysis of urea A. Chenite a,

    E-print Network

    Buschmann, Michael

    Monolithic gelation of chitosan solutions via enzymatic hydrolysis of urea A. Chenite a, *, S. Gori hydrolysis of urea is shown to produce pH-induced hydrogels with monolithic and homogeneous coherent 3D presented. q 2006 Elsevier Ltd. All rights reserved. Keywords: Chitosan; Monolithic hydrogel; Rheology; p

  12. Synthesis of urea in cometary model ices and implications for Comet 67P/Churyumov-Gerasimenko.

    PubMed

    Förstel, M; Maksyutenko, P; Jones, B M; Sun, B-J; Chang, A H H; Kaiser, R I

    2015-12-24

    Urea is considered a fundamental building block in prebiotic chemistry. Its formation on early Earth has not yet been explained satisfactorily and exogenous delivery has been considered. We report on the synthesis along with the first online and in situ identification of urea after exposing inorganic ices to ionizing radiation. PMID:26564002

  13. Urea Destabilizes RNA by Forming Stacking Interactions and Multiple Hydrogen Bonds with Nucleic Acid Bases

    E-print Network

    Thirumalai, Devarajan

    Acid Bases U. Deva Priyakumar, Changbong Hyeon, D. Thirumalai,*,§ and Alexander D. MacKerell, Jr interactions with amide- like surfaces of the nucleic acids. The average base-base interaction energies (GC, AU that have a high propensity to misfold can be resolved using moderate amounts of urea.2 Urea titrations can

  14. Origins of Protein Denatured State Compactness and Hydrophobic Clustering in Aqueous Urea: Inferences from

    E-print Network

    Chan, Hue Sun

    Origins of Protein Denatured State Compactness and Hydrophobic Clustering in Aqueous Urea capacity signature ( CP) of a compact denatured state can be similar to CP values calculated by assuming: hydrophobicity; urea denaturation; sol- vent accessible surface area; compact denatured states; m-value; heat

  15. 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...

  16. 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

  17. CLINICAL CONSEQUENCES OF UREA CYCLE ENZYME DEFICIENCIES AND POTENTIAL LINKS TO ARGININE AND NITRIC OXIDE METABOLISM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Urea cycle disorders (UCD) are human conditions caused by the dysregulation of nitrogen transfer from ammonia nitrogen into urea. The biochemistry and the genetics of these disorders were well elucidated. Earlier diagnosis and improved treatments led to an emerging, longer-lived cohort of patients. ...

  18. A Gas-Sensor-Based Urea Enzyme Electrode: Its Construction and Use in the Undergraduate Laboratory.

    ERIC Educational Resources Information Center

    Riechel, Thomas L.

    1984-01-01

    Describes an undergraduate experiment for the potentiometric determination of urea based on the physical entrapment of urease on the tip of an ammonia gas sensor. An advantage of this technique is the ease with which the ammonia electrode can be converted to a urea electrode. (JN)

  19. Mitigation of Ammonia Loss from Urea Applied to Moist Soils by Agrotain

    E-print Network

    Lawrence, Rick L.

    Mitigation of Ammonia Loss from Urea Applied to Moist Soils by Agrotain® Richard Engel and Clain). In Fertilizer Fact Sheet 59 we reported that ammonia (NH3) losses from cold soils (e.g. as the soil dried, a worst-case scenario for NH3 loss. Methods Ammonia losses from urea and Agrotain® treated

  20. MONTANAFERTILIZEReFACTS Ammonia loss from surface-applied urea to cold soils

    E-print Network

    Lawrence, Rick L.

    March 2015 MONTANAFERTILIZEReFACTS Ammonia loss from surface-applied urea to cold soils: A second as a result of ammonia (NH3) volatilization. The process occurs after urea granules applied to the soil. Ammonia losses were quantified using a micrometeorological mass- balance approach (http

  1. Microbial hydrolysis of urea and its subsequent nitrification in East Texas lignite mine spoil 

    E-print Network

    Waggoner, Paul James

    1993-01-01

    source due to its high N content (47.0 %) and economical price. Since little is known about the behavior of urea in the mixed overburden mine spoils of east Texas, a two-year study was conducted to determine rates of urea hydrolysis, and its subsequent...

  2. [Effects of coated controlled release urea combined with conventional urea on winter wheat growth and soil NO3- -N].

    PubMed

    Yi, Wen-ping; Sun, Zhe; Wu, Liang; Shi, Gui-fang; Zhu, Guo-liang; Li, Ya-xing; Gu, Jia-lin; Xu, Qiu-ming

    2011-03-01

    Field experiments were conducted to study the effects of different dosages coated controlled release urea (PCU60, 60 d release duration) combined with conventional urea (U) used as basal on the winter wheat grain yield, nitrogen (N) recovery rate, and soil NO3- -N content, etc. Five treatments were installed, i.e., U (CK), 10% PCU60+90% U (PU1), 20% PCU60+80% U (PU2), 30% PCU60+70% U (PU3), and 40% PCU60+60% U (PU4). In the meantime, a comparative analysis was also carried out on the PCU60 N release characteristics under field condition and in 25 "C static water. At the same N dosage, all the test indices in treatment PU4 were significantly higher, with the grain yield, N recovery rate, total N accumulation amount, total tiller number and aboveground biomass at ripening stage, and economic benefit increased by 5.6%, 14.6%, 7.2%, 2.6%, 7.5%, and 984.3 yuan x hm(-2), respectively, compared with those in treatment U. The accumulation amount of NO3- -N in 0-100 cm soil layer in all treatments ranged in 39.70-49.93 kg x hm-2, and was the lowest (39.70 kg x hm(-2)) in treatment PU4. The N release pattern of PCU60 under field condition better fitted the N absorption characteristics of winter wheat. PMID:21657025

  3. 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. ); Ferroni, E. ); Kevan, L. )

    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.

  4. Reduction of Cr(VI) by Urea-Dispersed Nanoscale Zero-Valent Iron.

    PubMed

    Zhang, Jing; Zhang, Guilong; Zheng, Kang; Cai, Dongqing; Wu, Zhengyan

    2015-08-01

    Urea was used to disperse nanoscale zero-valent iron (NZVI) for reduction of Cr(VI) to Cr(III) in aqueous solution. Scanning electron microscope and fourier transform-infrared spectra investigations demonstrated that urea could effectively increase the dispersion of NZVI resulting in more effective reduction sites (ERS) for Cr(VI) ions. Batch reduction experiments indicated that the reductive capacity of urea dispersed NZVI (UNZVI) was significantly improved, as the reductive efficiency reached 96.8% under optimal condition compared with the raw NZVI (72.14%). Additionally, the NZVI was stable for at least 28 days after urea treatment. The dispersion mechanism was proposed that the steric hindrance effect of the urea coating on the surface might play a key role in dispersing the NZVI particles. PMID:26369206

  5. Serum Uric Acid and Subsequent Cognitive Performance in Patients with Pre-Existing Cardiovascular Disease

    PubMed Central

    Molshatzki, Noa; Weinstein, Galit; Streifler, Jonathan Y.; Goldbourt, Uri; Tanne, David

    2015-01-01

    High serum uric acid (UA) levels are associated with numerous vascular risk factors, and vascular disease, that predispose patients to cognitive impairment, yet UA is also a major natural antioxidant and higher levels have been linked to slower progression of several neurodegenerative disease. In-order to test the association between UA and subsequent cognitive performance among patients that carry a high vascular burden, UA levels were determined by calorimetric enzymatic tests in a sub-cohort of patients with chronic cardiovascular disease who previously participating in a secondary prevention trial. After an average of 9.8±1.7 years, we assessed cognitive performance (Neurotrax Computerized Cognitive Battery) as well as cerebrovascular reactivity (CVR) and common carotid intima-media thickness (IMT). Among 446 men (mean age 62.3±6.4 yrs) mean UA levels were 5.8±1.1 mg/dL. Adjusted linear regression models revealed that low UA levels (bottom quintile) were associated with poorer cognitive performance. Adjusted differences between the bottom quintile and grouped top UA quintiles were (B coefficient±SE) ?4.23±1.28 for global cognitive scores (p = 0.001), ?4.69±1.81 for memory scores (p = 0.010), ?3.32±1.43 for executive scores (p = 0.020) and ?3.43±1.97 for visual spatial scores (p = 0.082). Significant difference was also found for attention scores (p = 0.015). Additional adjustment for impaired CVR and high common carotid IMT slightly attenuated the relationship. Stronger UA effect on cognitive performance was found for older (age>65) patients with significant age interaction for global cognitive score (p = 0.016) and for executive (p = 0.018) and attention domains (p<0.001). In conclusion, we demonstrate that low UA levels in patients with preexisting cardiovascular disease are associated with poorer cognitive function a decade later. These findings lend support to the hypothesis that oxidative stress may be involved in the pathogenesis of age-associated cognitive impairment. PMID:25794156

  6. Genetic parameters for carnitine, creatine, creatinine, carnosine, and anserine concentration in longissimus muscle and their association with palatability traits in Angus cattle.

    PubMed

    Mateescu, R G; Garmyn, A J; O'Neil, M A; Tait, R G; Abuzaid, A; Mayes, M S; Garrick, D J; Van Eenennaam, A L; VanOverbeke, D L; Hilton, G G; Beitz, D C; Reecy, J M

    2012-12-01

    The objective of this study was to estimate genetic parameters for carnitine, creatine, creatinine, carnosine, and anserine concentration in LM and to evaluate their associations with Warner-Bratzler shear force (WBSF) and beef palatability traits. Longissimus muscle samples from 2,285 Angus cattle were obtained and fabricated into steaks for analysis of carnitine, creatine, creatinine, carnosine, anserine, and other nutrients, and for trained sensory panel and WBSF assessments. Restricted maximum likelihood procedures were used to obtain estimates of variance and covariance components under a multiple-trait animal model. Estimates of heritability for carnitine, creatine, creatinine, carnosine, and anserine concentrations in LM from Angus cattle were 0.015, 0.434, 0.070, 0.383, and 0.531, respectively. Creatine, carnosine, and anserine were found to be moderately heritable, whereas almost no genetic variation was observed in carnitine and creatinine. Moderate positive genetic (0.25, P < 0.05) and phenotypic correlations (0.25, P < 0.05) were identified between carnosine and anserine. Medium negative genetic correlations were identified between creatine and both carnosine (-0.53, P < 0.05) and anserine (-0.46, P < 0.05). Beef and livery/metallic flavor were not associated with any of the 5 compounds analyzed (P > 0.10), and carnitine concentrations were not associated (P > 0.10) with any of the meat palatability traits analyzed. Carnosine was negatively associated with overall tenderness as assessed by trained sensory panelists. Similar negative associations with overall tenderness were identified for creatinine and anserine. Painty/fishy was the only flavor significantly and negatively associated with creatinine and carnosine. These results provide information regarding the concentration of these compounds, the amount of genetic variation, and evidence for negligible associations with beef palatability traits in LM of beef cattle. PMID:22952371

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

    SciTech Connect

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

    1981-11-01

    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 a scavenger of singlet oxygen and radicals. We show that, at physiological concentrations, urate reduces the oxo-heme oxidant formed by peroxide reaction with hemoglobin, protects erythrocyte ghosts against lipid peroxidation, and protects erythrocytes from peroxidative damage leading to lysis. Urate is about as effective an antioxidant as ascorbate in these experiments. Urate is much more easily oxidized than deoxynucleosides by singlet oxygen and is destroyed by hydroxyl radicals at a comparable rate. The plasma urate level in humans (about 300 ..mu..M) is considerably higher than the ascorbate level, making it one of the major antioxidants in humans. Previous work on urate reported in the literature supports our experiments and interpretations, although the findings were not discussed in a physiological context.

  8. Electrochemical Sensing of Dopamine, Uric Acid and Ascorbic Acid Using tRGO-TiO2 Nanocomposites.

    PubMed

    Rajamani, A R; Kannan, Rajesh; Krishnan, Sruthy; Ramakrishnan, S; Raj, S Mohan; Kumaresan, D; Kothurkar, Nikhil; Rangarajan, Murali

    2015-07-01

    This work reports a graphene-based nonenzymatic electrochemical sensing platform for the detection of dopamine (DA), uric acid (UA), and ascorbic acid (AA). Graphene oxide, synthesized by modified Hummers method, was thermally reduced in an induction furnace at 200 °C in an Ar-H2 atmosphere to obtain thermally reduced graphene oxide (tRGO). Nanocomposites of tRGO-TiO2 were obtained by a hydrothermal method, and were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD). FTIR spectra showed Ti-O-C peaks, indicating covalent linkage between the TiO2 nanoparticles and the reduced graphene oxide sheets. Glassy carbon electrode (GCE) was modified with the nanocomposite (tRGO-TiO2-GCE), and the modified electrode could detect dopamine (DA: 1 to 1000 µM), uric acid (UA: 1 to 900 µM), and ascorbic acid (AA: 10 to 1000 µM) in each other's presence over wide ranges, with adequate separation in peak potentials. Differential pulse voltammetry experiments yielded linear responses with sensitivities of 133.18, 33.96, and 155.59 µA mM(-1) cm(-2) for DA, UA, and AA, respectively. PMID:26373074

  9. Potent Urea and Carbamate Inhibitors of Soluble Epoxide Hydrolases

    NASA Astrophysics Data System (ADS)

    Morisseau, Christophe; Goodrow, Marvin H.; Dowdy, Deanna; Zheng, Jiang; Greene, Jessica F.; Sanborn, James R.; Hammock, Bruce D.

    1999-08-01

    The soluble epoxide hydrolase (sEH) plays a significant role in the biosynthesis of inflammation mediators as well as xenobiotic transformations. Herein, we report the discovery of substituted ureas and carbamates as potent inhibitors of sEH. Some of these selective, competitive tightbinding inhibitors with nanomolar Ki values interacted stoichiometrically with the homogenous recombinant murine and human sEHs. These inhibitors enhance cytotoxicity of trans-stilbene oxide, which is active as the epoxide, but reduce cytotoxicity of leukotoxin, which is activated by epoxide hydrolase to its toxic diol. They also reduce toxicity of leukotoxin in vivo in mice and prevent symptoms suggestive of acute respiratory distress syndrome. These potent inhibitors may be valuable tools for testing hypotheses of involvement of diol and epoxide lipids in chemical mediation in vitro or in vivo systems.

  10. Macrocyclic bis(ureas) as ligands for anion complexation

    PubMed Central

    Kretschmer, Claudia; Dittmann, Gertrud

    2014-01-01

    Summary Two macrocyclic bis(ureas) 1 and 2, both based on diphenylurea, have been synthesized. Compound 1 represents the smaller ring with two ethynylene groups as linkers and 2 the larger ring with two butadiynylene groups. On thermal treatment to 130 °C molecule 1 splits up into two dihydroindoloquinolinone (3) molecules. Both compounds 1 and 2 form adducts with polar molecules such as dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) and act as complexing agents towards a series of anions (Cl?, Br?, I?, NO3 ?, HSO4 ?). The crystal structures of 3, 2·2DMSO, 2·2DMF, and of the complex NEt4[Br·2] have been determined. Quantitative investigations of the complexation equilibria were performed via 1H NMR titrations. While 1 is a rather weak complexing agent, the large ring of 2 binds anions with association constants up to log K = 7.93 for chloride ions. PMID:25161744

  11. Description of microparticles in urea-formaldehyde foam insulation products

    SciTech Connect

    Nantel, A.J.; Huy, N.D.; Roy, P.E.; Duchesneau, L.; Weber, J.P.

    1985-04-01

    Thousands of families living in homes insulated with urea-formaldehyde foam (UFF) have complained of various health problems. This product is now banned from the market both in Canada and the United States. Formaldehyde gas emitted by the products has been considered to be the source of these health problems but this cause-effect relationship has not been confirmed as yet. It has been suggested that other contaminants released by the foam could be involved. Work initiated to verify this possibility has permitted the observation of microparticles of less than 1 ..mu..m in diameter in foam samples obtained from various houses. The microparticles can easily be removed from the foam by passing air through it or, simply, by immersing it in water. These particles have been studied by different microscopy techniques and their morphological characteristics are described. They may represent a potential health risk.

  12. NITROGEN AND PHOSPHORUS UTILIZATION BY BEEF CATTLE FED THREE DIETARY CRUDE PROTEIN LEVELS WITH THREE LEVELS OF SUPPLEMENTAL UREA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three dietary CP levels (11.5, 13.0, and 14.5\\% of DM) and three supplemental urea levels (100, 50, and 0\\% of supplemental CP from urea) were fed to determine performance, serum urea N (SUN), and N and P balance. Crossbred steers (n = 27; average BW = 315 kg) were blocked by weight and individuall...

  13. 76 FR 23835 - Solid Urea From Russia and Ukraine; Scheduling of Full Five-Year Reviews Concerning the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-28

    ...340-H (Third Review)] Solid Urea From Russia and Ukraine; Scheduling of Full Five-Year...Antidumping Duty Orders on Solid Urea From Russia and Ukraine AGENCY: United States International...antidumping duty orders on solid urea from Russia and Ukraine would be likely to lead...

  14. 76 FR 19747 - Solid Urea From the Russian Federation and Ukraine: Final Results of the Expedited Sunset Reviews...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-08

    ...solid urea from the Russian Federation (Russia) and Ukraine, pursuant to section 751...antidumping duty orders \\1\\ on solid urea from Russia and Ukraine pursuant to section 751...antidumping duty orders on solid urea from Russia and Ukraine. Scope of the Orders...

  15. Keeping the shape but changing the charges: A simulation study of urea and its iso-steric analogs

    E-print Network

    Levitt, Michael

    -shaped analogs, which aggregate more as they become less polar, we find that urea mixes well in solution and has urea's unique behavior in comparison to its Y-shaped analogs has clear implications for models of urea the solubili- ties of most amino acids with hydrophobic or amide- containing side chains. Building upon

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

    E-print Network

    What is Milk Urea Nitrogen and How is It Interpreted? Dr. Doo-Hong Min, Extension Forage Specialist, MSU UPES Milk urea nitrogen (MUN) is another tool to assess the protein and energy balance status of a group of dairy cows and can be used for minimizing feed costs while maximizing production. Milk urea

  17. 75 FR 40827 - Petitions Concerning Whether Ammonia or Urea Sold or Distributed and Used for Certain Purposes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-14

    ...FRL-8836-6] Petitions Concerning Whether Ammonia or Urea Sold or Distributed and Used for...concerning petitions concerning whether ammonia or urea sold or distributed and used for...comment on petitions concerning whether ammonia or urea sold or distributed and used...

  18. Urea concentration in minor mucous gland secretions and the effect of salivary film velocity on urea metabolism by Streptococcus vestibularis in an artificial plaque.

    PubMed

    Macpherson, L M; Dawes, C

    1991-09-01

    Our purpose was to determine the urea concentration in minor mucous gland (MMG) secretions and the pH at proximal and distal aspects of the lower surface of artificial plaque in vitro during infusion of urea solutions over the surface, at different film velocities. Saliva is present in the mouth as a slowly moving film (ca. 0.1 mm thick) with an estimated velocity in the range of 0.8-8.0 mm/min. At low velocities, due to the accumulation of bacterial products, a progressive increase in their concentration may occur in both the plaque and the overlying salivary film at the distal edge (where the film leaves the plaque). S. vestibularis, an oral micro-organism possessing ureolytic activity, was combined with 1% agarose, to give a urease Vmax similar to that of natural plaque. The artificial plaque was in the chamber (6.0 x 6.0 square and 0.5 or 1.5 mm deep) of a diffusion apparatus, and a urea-containing artificial saliva (3.3 or 13.2 mmol/l) was infused over the surface, as a film 0.1 mm deep, at velocities of 0.8, 8.2 and 86.2 mm/min. At the lower (physiologically normal) urea concentration and the two lower film velocities, most urea appeared to be metabolized at the proximal end of the plaque, which developed a higher pH. At the higher urea concentration, and a film velocity of 8 mm/min, a higher pH was found at the distal end. This was probably due to the combination of greater urea availability and a reduced rate of ammonia loss distally. At a film velocity of 86.2 mm/min, proximal/distal pH gradients did not develop.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1832451

  19. [FTIR spectra study on the swellbility and controlled-release mechanism of polyurethane coated urea].

    PubMed

    Wu, Shu; Ru, Tie-Jun; Wang, Jin-Ming

    2013-05-01

    The nutrient release experiment of polyurethane coated urea (PCU) was carried out in pure water at 25 degrees C. With the release of urea, the structural variation of polyurethane coating was investigated by Fourier transform infrared spectroscopy (FTIR), then a series of curves were collated and compared so as to better reflect the relation between diffusion rate of urea and coating structure. It was found that when the nutrient was released by 50% wt, new absorption peaks at 3 435, 3 342, 1 671, 1 621, 1 448 and 1 159 cm(-1) appear in the FTIR spectra of polyurethane coating, moreover, the height of these absorption peaks was increased gradually when the nutrient was released by 70% wt, more importantly, these new absorption peaks are consistent with the characteristic absorption peaks of urea fertilizer, the spectra of urea were mainly characterized by bands at 3 440, 3 346, 1 672, 1 621 and 1 461 cm(-1). The results show that the IR spectra variation was caused by the content of urea, existing in the polyurethane coating, and was increased gradually, The more the urea content, the greater the swelling degree of the polyurethane coating. The swelling of polyurethane coating leads to the pores size change, and release rate is increased, so the "S" pattern curve of the nitrogen accumulative release is formed. PMID:23905318

  20. Vasopressin regulation of the renal UT-A3 urea transporter.

    PubMed

    Stewart, G S; Thistlethwaite, A; Lees, H; Cooper, G J; Smith, Craig

    2009-03-01

    Facilitative urea transporters in the mammalian kidney play a vital role in the urinary concentrating mechanism. The urea transporters located in the renal inner medullary collecting duct, namely UT-A1 and UT-A3, are acutely regulated by the antidiuretic hormone vasopressin. In this study, we investigated the vasopressin regulation of the basolateral urea transporter UT-A3 using an MDCK-mUT-A3 cell line. Within 10 min, vasopressin stimulates urea flux through UT-A3 transporters already present at the plasma membrane, via a PKA-dependent process. Within 1 h, vasopressin significantly increases UT-A3 localization at the basolateral membrane, causing a further increase in urea transport. While the basic trafficking of UT-A3 to basolateral membranes involves both protein kinase C and calmodulin, its regulation by vasopressin specifically occurs through a casein kinase II-dependent pathway. In conclusion, this study details the effects of vasopressin on UT-A3 urea transporter function and hence its role in regulating urea permeability within the renal inner medullary collecting duct. PMID:19052101

  1. NMR Studies of Cu/zeolite SCR Catalysts Hydrothermally Aged with Urea

    SciTech Connect

    Cheng, Yisun; Hoard, John; Lambert, Christine; Kwak, Ja Hun; Peden, Charles HF

    2008-06-26

    The effects of hydrothermal aging of Cu/zeolite urea-SCR catalysts on their reactivity and material properties was assessed by performance tests and multiple characterization techniques that included 27Al NMR and XRD. Three aging protocols were used that consisted of varying temperature during hydrothermal aging with or without exposure to aqueous urea solution. Differences in behavior were even found for samples hydrothermally aged immediately following exposure to the urea solution or if the sample was dried overnight before hydrothermal aging. The combination of urea and high temperature exposure increased the deactivation of Cu/zeolite SCR catalysts beyond that observed by hydrothermal aging alone, with an immediate high temperature exposure following wetting of the catalyst core with aqueous urea causing the most significant deterioration in performance. The impact of urea on SCR catalyst durability was also found to increase with the aging temperature. NMR analysis suggested that aging with urea resulted in relatively more dealumination of the zeolite for the SCR catalysts in this study.

  2. Adaptive network based on fuzzy inference system for equilibrated urea concentration prediction.

    PubMed

    Azar, Ahmad Taher

    2013-09-01

    Post-dialysis urea rebound (PDUR) has been attributed mostly to redistribution of urea from different compartments, which is determined by variations in regional blood flows and transcellular urea mass transfer coefficients. PDUR occurs after 30-90min of short or standard hemodialysis (HD) sessions and after 60min in long 8-h HD sessions, which is inconvenient. This paper presents adaptive network based on fuzzy inference system (ANFIS) for predicting intradialytic (Cint) and post-dialysis urea concentrations (Cpost) in order to predict the equilibrated (Ceq) urea concentrations without any blood sampling from dialysis patients. The accuracy of the developed system was prospectively compared with other traditional methods for predicting equilibrated urea (Ceq), post dialysis urea rebound (PDUR) and equilibrated dialysis dose (eKt/V). This comparison is done based on root mean squares error (RMSE), normalized mean square error (NRMSE), and mean absolute percentage error (MAPE). The ANFIS predictor for Ceq achieved mean RMSE values of 0.3654 and 0.4920 for training and testing, respectively. The statistical analysis demonstrated that there is no statistically significant difference found between the predicted and the measured values. The percentage of MAE and RMSE for testing phase is 0.63% and 0.96%, respectively. PMID:23806679

  3. Highly sensitive and selective uric acid biosensor based on a three-dimensional graphene foam/indium tin oxide glass electrode.

    PubMed

    Yue, Hong Yan; Zhang, Hong; Chang, Jing; Gao, Xin; Huang, Shuo; Yao, Long Hui; Lin, Xuan Yu; Guo, Er Jun

    2015-11-01

    A three-dimensional (3D) continuous and interconnected network graphene foam (GF) was synthesized by chemical vapor deposition using nickel foam as a template. The morphologies of the GF were observed by scanning electron microscopy. X-ray diffraction and Raman spectroscopy were used to investigate the structure of GF. The graphene with few layers and defect free was closely coated on the backbone of the 3D nickel foam. After etching nickel, the GF was transferred onto indium tin oxide (ITO) glass, which acted as an electrode to detect uric acid using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The GF/ITO electrode showed a high sensitivity for the detection of uric acid: approximately 9.44 mA mM(-1) in the range of 25 nM-0.1 ?M and 1.85 mA mM(-1) in the range of 0.1-60 ?M. The limit of detection of GF/ITO electrode for uric acid is 3 nM. The GF/ITO electrode also showed a high selectivity for the detection of uric acid in the presence of ascorbic acid. This electrode will have a wide range of potential application prospects in electrochemical detection. PMID:26254685

  4. Enhanced-efficiency fertilizers in nitrous oxide emissions from urea applied to sugarcane.

    PubMed

    Soares, Johnny R; Cantarella, Heitor; Vargas, Vitor P; Carmo, Janaina B; Martins, Acácio A; Sousa, Rafael M; Andrade, Cristiano A

    2015-03-01

    The environmental benefits of producing biofuels from sugarcane have been questioned due to greenhouse gas emissions during the biomass production stage, especially nitrous oxide (NO) associated with nitrogen (N) fertilization. The objective of this work was to evaluate the use of nitrification inhibitors (NIs) dicyandiamide (DCD) and 3,4 dimethylpyrazole phosphate (DMPP) and a controlled-release fertilizer (CRF) to reduce NO emissions from urea, applied at a rate of 120 kg ha of N. Two field experiments in ratoon cycle sugarcane were performed in Brazil. The treatments were (i) no N (control), (ii) urea, (iii) urea+DCD, (iv) urea+DMPP, and (v) CRF. Measurements of NO fluxes were performed using static chambers with four replications. The measurements were conducted three times per week during the first 3 mo and biweekly afterward for a total of 217 and 382 d in the first and second seasons, respectively. The cumulative NO-N emissions in the first ratoon cycle were 1098 g ha in the control treatment and 1924 g ha with urea (0.7% of the total N applied). Addition of NIs to urea reduced NO emissions by more than 90%, which did not differ from those of the plots without N. The CRF treatment showed NO emissions no different from those of urea. The results were similar in the second ratoon: the treatment with urea showed NO emissions of 0.75% of N applied N. Application of NIs resulted in a strong reduction in NO emissions, but CRF increased emissions compared with urea. We therefore conclude that both NIs can be options for mitigation of greenhouse gas emission in sugarcane used for bioenergy. PMID:26023961

  5. Sequential Dissociation of Subunits from Bovine Heart Cytochrome c Oxidase by Urea

    PubMed Central

    Sedlák, Erik; Robinson, Neal C.

    2009-01-01

    The quaternary stability of purified, detergent-solubilized, cytochrome c oxidase (CcO) was probed using two chemical denaturants, urea, and guanidinium chloride. Each chaotrope induces dissociation of five subunits in a concentration dependent manner. These five subunits are not scattered over the surface of CcO, but are clustered together in close contact at the dimer interface. Increasing the concentration of urea selectively dissociates subunits from CcO in the following order: VIa & VIb, followed by III & VIIa, and finally Vb. After incubation in urea for 10 min at room temperature, the sigmoidal dissociation transitions were centered at 3.7 M, 4.6 M, and 7.0 M urea, respectively. The secondary structure of CcO was only minimally perturbed, indicating that urea causes disruption of subunit interactions without urea-induced conformational changes. Incubation of CcO in urea for 120 min produced similar results, but shifted the sigmoidal dissociation curves to lower urea concentrations. Incubation of CcO with increasing concentrations of guanidinium chloride (GdmCl) produces an analogous effect; however, the GdmCl-induced dissociation of subunits occurs at lower concentrations and with a narrower concentration range. Thermodynamic parameters for each subunit dissociation were evaluated from the sigmoidal dissociation data by assuming a single transition from bound to dissociated subunit. The free energy change accompanying urea-induced dissociation of each subunit ranged from 18.0 to 29.7 kJ/mol, which corresponds to 0.32 to 0.59 kJ/mol per 100 Ĺ2 of newly exposed solvent accessible surface area. These values are 30-50-fold smaller than previously reported for the unfolding of soluble or membrane proteins. PMID:19663452

  6. Alternative channels for urea in the inner medulla of the rat kidney.

    PubMed

    Nawata, C Michele; Dantzler, William H; Pannabecker, Thomas L

    2015-12-01

    The ascending thin limbs (ATLs) and lower descending thin limbs (DTLs) of Henle's loop in the inner medulla of the rat are highly permeable to urea, and yet no urea transporters have been identified in these sections. We hypothesized that novel, yet-unidentified transporters in these tubule segments could explain the high urea permeability. cDNAs encoding for Na(+)-glucose transporter 1a (SGLT1a), Na(+)-glucose transporter 1 (NaGLT1), urea transporter (UT)-A2c, and UT-A2d were isolated and cloned from the Munich-Wistar rat inner medulla. SGLT1a is a novel NH2-terminal truncated variant of SGLT1. NaGLT1 is a Na(+)-dependent glucose transporter primarily located in the proximal tubules and not previously described in the thin limbs. UT-A2c and UT-A2d are novel variants of UT-A2. UT-A2c is truncated at the COOH terminus, and UT-A2d has one exon skipped. When rats underwent water restriction for 72 h, mRNA levels of SGLT1a increased in ATLs, NaGLT1 levels increased in both ATLs and DTLs, and UT-A2c increased in ATLs. [(14)C]urea uptake assays performed on Xenopus oocytes heterologously expressing these proteins revealed that despite having structural differences from their full-length versions, SGLT1a, UT-A2c, and UT-A2d enhanced urea uptake. NaGLT1 also facilitated urea uptake. Uptakes were Na(+) independent and inhibitable by phloretin and/or phloridzin. Our data indicate that there are several alternative channels for urea in the rat inner medulla that could potentially contribute to the high urea permeabilities in thin limb segments. PMID:26423860

  7. An alternative explanation for the collapse of unfolded proteins in an aqueous mixture of urea and guanidinium chloride

    NASA Astrophysics Data System (ADS)

    Graziano, Giuseppe

    2014-09-01

    Molecular dynamics simulations have shown that a totally unfolded protein in aqueous 8 M urea undergoes a collapse transition on replacing urea molecules by guanidinium chloride, GdmCl, assuming a compact conformation in 4 M urea + 4 M GdmCl [J. Am. Chem. Soc. 134 (2012) 18266]. This is unexpected because GdmCl is a denaturant stronger than urea. It is shown that such collapse can originate from an increase in the magnitude of the solvent-excluded volume effect due the high density of urea + GdmCl mixtures, coupled to their low water number density that pushes denaturant molecules toward the protein surface.

  8. On the ability of trehalose to offset the denaturing activity of urea

    NASA Astrophysics Data System (ADS)

    Graziano, Giuseppe

    2013-01-01

    Experimental and computational studies indicate that trehalose offsets the denaturing activity of urea. According to a statistical thermodynamic model, the fundamental stabilizing contribution arises from the difference in the work to create a cavity suitable to host the D-state and the N-state, respectively. The magnitude of this solvent-excluded volume effect increases with aqueous solution density. Trehalose and urea addition to water leads to a density increase, that translates in an increase in the magnitude of the solvent-excluded volume effect which is so large to overwhelm the destabilizing contribution arising from the energetic attractions of urea with protein surface groups.

  9. Urea for management of the syndrome of inappropriate secretion of ADH: A systematic review.

    PubMed

    de Solŕ-Morales, Oriol; Riera, Maribel

    2014-11-01

    Urea has been recently proposed for the management of hyponatremia linked to the syndrome of inappropriate secretion of ADH (SIADH). The objective of the study was to review the levels of evidence for treatment of hyponatremia associated with SIADH with urea. We performed a: systematic review of experimental trials and grading according to SIGN. No clinical trials were found. The 6 studies analysed had methodological limitations and were prone to biases. In conclusion, there is no evidence to support the efficacy of urea for the treatment of hyponatremia following SIADH. PMID:24954885

  10. Effect of amino acids on the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in creatinine/phenylalanine and creatinine/phenylalanine/4-oxo-2-nonenal reaction mixtures.

    PubMed

    Zamora, Rosario; Alcón, Esmeralda; Hidalgo, Francisco J

    2013-12-15

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation in mixtures of creatinine, phenylalanine, amino acids and 4-oxo-2-nonenal was studied, to analyse the role of amino acids on the generation of this heterocyclic aromatic amine. When oxidised lipid was absent, cysteine, serine, aspartic acid, threonine, asparagine, tryptophan, tyrosine, proline, and methionine increased significantly (p < 0.05) the amount of PhIP formed in comparison to the control. When lipid was present, only the addition of methionine, glycine, and serine increased significantly (p < 0.05) the amount of PhIP produced, while histidine, cysteine, lysine, tryptophan, tyrosine, and alanine reduced significantly (p < 0.05) PhIP. These results may be a consequence of the different competitive reactions that occur. Thus, in the absence of lipids, thermal decomposition of the amino acids produced reactive carbonyls that converted phenylalanine into phenylacetaldehyde as a key step in the formation of PhIP. When oxidised lipid was present, amino acids competed with phenylalanine for the lipid, and amino acid degradation products were formed, among which alpha-keto acids seemed to play a role in these reactions. These results suggest that PhIP can be produced by several alternative reaction pathways from all major food components, including amino acids and lipids, in addition to carbohydrates. PMID:23993611

  11. 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

  12. Accuracy of point-of-care serum creatinine devices for detecting patients at risk of contrast-induced nephropathy: a critical overview.

    PubMed

    Martínez Lomakin, Felipe; Tobar, Catalina

    2014-12-01

    Contrast-induced nephropathy (CIN) is a common event in hospitals, with reported incidences ranging from 1 to 30%. Patients with underlying kidney disease have an increased risk of developing CIN. Point-of-care (POC) creatinine devices are handheld devices capable of providing quantitative data on a patient's kidney function that could be useful in stratifying preventive measures. This overview aims to synthesize the current evidence on diagnostic accuracy and clinical utility of POC creatinine devices in detecting patients at risk of CIN. Five databases were searched for diagnostic accuracy studies or clinical trials that evaluated the usefulness of POC devices in detecting patients at risk of CIN. Selected articles were critically appraised to assess their individual risk of bias by the use of standard criteria; 13 studies were found that addressed the diagnostic accuracy or clinical utility of POC creatinine devices. Most studies incurred a moderate to high risk of bias. Overall concordance between POC devices and reference standards (clinical laboratory procedures) was found to be moderate, with 95% limits of agreement often lying between -35.4 and +35.4?µmol/L (-0.4 and +0.4?mg/dL). Concordance was shown to decrease with worsening kidney function. Data on the clinical utility of these devices were limited, but a significant reduction in time to diagnosis was reported in two studies. Overall, POC creatinine devices showed a moderate concordance with standard clinical laboratory creatinine measurements. Several biases could have induced optimism in these estimations. Results obtained from these devices may be unreliable in cases of severe kidney failure. Randomized trials are needed to address the clinical utility of these devices. PMID:25033794

  13. 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

  14. Differences in estimation of creatinine generation between renal function estimating equations in an Indian population: cross-sectional data from the Hyderabad arm of the Indian migration study

    PubMed Central

    2013-01-01

    Background Creatinine based formulae for estimating renal function developed in white populations may be less valid in other ethnic groups. We assessed the performance of various estimating formulae in an Indian population. Methods 917 subjects were recruited from the Hyderabad arm of the Indian Migration Study. Data were collected on comorbidity, serum creatinine and body composition from DXA scans. Renal function was compared using the modified Cockcroft-Gault, MDRD and CKD-EPI formulae. 24-hour creatinine production was derived from each estimate and the agreement with measured muscle mass examined. 24-hour creatinine production estimates were compared to that derived from a formula by Rule incorporating DXA measured muscle mass. Potential systematic biases were examined by age and eGFR. We assessed the association of renal function by each formula with hypertension and self-reported measures of vascular disease. Results Mean modified Cockcroft-Gault eCCl was 98.8?ml/min/1.73?m2, MDRD eGFR 91.2?ml/min/1.73?m2 and CKD-EPI eGFR 96.3?ml/min/1.73?m2. MDRD derived 24-hour creatinine production showed the least age-related underestimation compared to the Rule formula. CKD-EPI showed a marked bias at higher eGFRs. All formulae showed similar strength associations with vascular disease and hypertension. Conclusions Our analyses support the use of MDRD for estimating renal function in Indian populations. Further work is required to assess the predictive value of formulae for incident disease and complications of CKD. PMID:23379609

  15. Clec12a is an inhibitory receptor for uric acid crystals that regulates inflammation in response to cell death.

    PubMed

    Neumann, Konstantin; Castińeiras-Vilarińo, Mercedes; Höckendorf, Ulrike; Hannesschläger, Nicole; Lemeer, Simone; Kupka, Danny; Meyermann, Svenia; Lech, Maciej; Anders, Hans-Joachim; Kuster, Bernhard; Busch, Dirk H; Gewies, Andreas; Naumann, Ronald; Groß, Olaf; Ruland, Jürgen

    2014-03-20

    Recognition of cell death by the innate immune system triggers inflammatory responses. However, how these reactions are regulated is not well understood. Here, we identify the inhibitory C-type lectin receptor Clec12a as a specific receptor for dead cells. Both human and mouse Clec12a could physically sense uric acid crystals (monosodium urate, MSU), which are key danger signals for cell-death-induced immunity. Clec12a inhibited inflammatory responses to MSU in vitro, and Clec12a-deficient mice exhibited hyperinflammatory responses after being challenged with MSU or necrotic cells and after radiation-induced thymocyte killing in vivo. Thus, we identified a negative regulatory MSU receptor that controls noninfectious inflammation in response to cell death that has implications for autoimmunity and inflammatory disease. PMID:24631154

  16. Electrochemical detection of uric acid using ruthenium-dioxide-coated carbon nanotube directly grown onto Si wafer

    NASA Astrophysics Data System (ADS)

    Shih, Yi-Ting; Lee, Kuei-Yi; Lin, Chung-Kuang

    2015-12-01

    Carbon nanotubes (CNTs) directly grown onto a Si substrate by thermal chemical vapor deposition were used in uric acid (UA) detection. The process is simple and formation is easy without the need for additional chemical treatments. However, CNTs lack selectivity and sensitivity to UA. To enhance the electrochemical analysis, ruthenium oxide was used as a catalytic mediator in the modification of electrodes. The electrochemical results show that RuO2 nanostructures coated onto CNTs can strengthen the UA signal. The peak currents of RuO2 nanostructures coated onto CNTs linearly increase with increasing UA concentration, meaning that they can work as electrodes for UA detection. The lowest detection limit and highest sensitivity were 55 nM and 4.36 µA/µM, respectively. Moreover, the characteristics of RuO2 nanostructures coated onto CNTs were examined by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy.

  17. Simultaneous determination of dopamine and uric acid using layer-by-layer graphene and chitosan assembled multilayer films.

    PubMed

    Weng, Xuexiang; Cao, Qingxue; Liang, Lixin; Chen, Jianrong; You, Chunping; Ruan, Yongmin; Lin, Hongjun; Wu, Lanju

    2013-12-15

    Multilayer films containing graphene (Gr) and chitosan (CS) were prepared on glassy carbon electrodes with layer-by-layer (LBL) assembly technique. After being characterized with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM), the electrochemical sensor based on the resulted films was developed to simultaneously determine dopamine (DA) and uric acid (UA). The LBL assembled electrode showed excellent electrocatalytic activity towards the oxidation of DA and UA. In addition, the self-assembly electrode possessed an excellent sensing performance for detection of DA and UA with a linear range from 0.1 ?M to 140 µM and from 1.0 µM to 125 µM with the detection limit as low as 0.05 µM and 0.1 µM based on S/N=3, respectively. PMID:24209353

  18. Spectroscopic analyses and studies on respective interaction of cyanuric acid and uric acid with bovine serum albumin and melamine

    NASA Astrophysics Data System (ADS)

    Chen, Dandan; Wu, Qiong; Wang, Jun; Wang, Qi; Qiao, Heng

    2015-01-01

    In this work, the fluorescence quenching was used to study the interaction of cyanuric acid (CYA) and uric acid (UA) with bovine serum albumin (BSA) at two different temperatures (283 K and 310 K). The bimolecular quenching constant (Kq), apparent quenching constant (Ksv), effective binding constant (KA) and corresponding dissociation constant (KD), binding site number (n) and binding distance (r) were calculated by adopting Stern-Volmer, Lineweaver-Burk, Double logarithm and overlap integral equations. The results show that CYA and UA are both able to obviously bind to BSA, but the binding strength order is BSA + CYA < BSA + UA. And then, the interactions of CYA and UA with melamine (MEL) under the same conditions were also studied by using similar methods. The results indicates that both CYA and UA can bind together closely with melamine (MEL). It is wished that these research results would facilitate the understanding the formation of kidney stones and gout in the body after ingesting excess MEL.

  19. Gilbert Moeckel, M.D., Ph.D., F.A.S.N Renal Pathology and Electron Microscopy Lab

    E-print Network

    : Urinary Findings: Sediment Morphology: Protein (G/24 hours): Urine Protein/Creatinine Ratio: IVP Hepatitis C Creatinine Glucose C3 C4 Hepatitis B Creatinine Clearance ASO Cryoglobulins HIV Uric Acid C

  20. Protein-enriched meal replacements do not adversely affect liver, kidney or bone density: an outpatient randomized controlled trial

    E-print Network

    Li, Zhaoping; Treyzon, Leo; Chen, Steve; Yan, Eric; Thames, Gail; Carpenter, Catherine L

    2010-01-01

    p = 0.650), 24 hour urine creatinine clearance (HP -0.02 ±of serum creatinine, urea nitrogen and urine nitrogen andurine samples were collected at base- line and week 52 for urinary urea nitrogen, creatinine,