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Sample records for urea creatinine uric

  1. Urea nitrogen, creatinine, and uric acid levels in postmortem serum, vitreous humor, and pericardial fluid.

    PubMed

    Palmiere, Cristian; Mangin, Patrice

    2015-03-01

    Urea nitrogen, creatinine, and uric acid are relatively stable in postmortem serum and may, therefore, be used for diagnostic purposes when chronic kidney disease and end-stage renal failure are investigated as causes of death. Nevertheless, uncertainties remain in defining the best alternative to postmortem serum for the identification and assessment of significantly decreased kidney function. In this study, we investigated urea nitrogen, creatinine, and uric acid levels in postmortem serum, pericardial fluid, and vitreous humor in a series of medico-legal cases (500 autopsies) with various causes of death. No postmortem interval-related differences were observed in any of the investigated fluids for any analyzed parameter, confirming the biochemical stability of all compounds after death. Data analysis failed to reveal statistically significant differences between postmortem serum and pericardial fluid urea nitrogen, creatinine, and uric acid concentrations. Conversely, statistically significant differences were observed in all analyzed biomarkers between postmortem serum and vitreous humor levels, with lower concentrations of all markers measured in vitreous. The results of this study suggest that, in order to estimate as accurately as possible blood analyte concentrations at the time of death, pericardial fluid should be preferred to vitreous humor.

  2. Evaluation of postmortem urea nitrogen, creatinine and uric acid levels in pericardial fluid in forensic autopsy.

    PubMed

    Zhu, Bao-Li; Ishikawa, Takaki; Michiue, Tomomi; Li, Dong-Ri; Zhao, Dong; Quan, Li; Maeda, Hitoshi

    2005-10-01

    In postmortem biochemistry, there is insufficient data available for the practical analysis of factors in the pericardial fluid. The aim of the present study was to examine postmortem pericardial fluid for urea nitrogen (UN), creatinine (Cr) and uric acid (UA) levels to investigate the pathophysiology of death in forensic autopsy cases (total, n = 409; within 48 h postmortem), which included blunt, sharp instrument injury, asphyxiation, drowning, fire fatalities, hyperthermia, hypothermia, methamphetamine-related fatalities, other poisoning, delayed death from trauma and natural diseases. There was a significant elevation in the three markers for chronic renal failure, gastrointestinal bleeding, hyperthermia, hypothermia, methamphetamine fatalities and delayed traumatic death, which was comparable with the clinical criteria for their serum levels. These postmortem findings showed azotemia due to renal failure, elevated protein catabolism and rhabdomyolysis. Although the pericardial levels were otherwise similar to the clinical serum reference ranges, only the drowning fatalities showed significantly lower levels for each marker. These observations suggested the stability of UN, Cr and UA in the pericardial fluid within 48 h postmortem and their usefulness for the pathophysiological investigation of death involving azotemia.

  3. 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.

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

    PubMed

    Lumeij, J T; Remple, J D

    1991-03-01

    Significant post-prandial increases in plasma uric acid and plasma urea concentrations were observed in peregrine falcons. Post-prandial uric acid concentrations were similar to those in birds suffering from hyperuricaemia and gout and were well above the theoretical limit of solubility of sodium urate in plasma. It is not clear why under normal circumstances no urate deposits occur in peregrine falcons (and probably other raptorial birds), which show hyperuricaemia for at least 12 h after ingesting a natural meal. It is important to evaluate renal function in peregrine falcons (and perhaps other birds) after a 24-h fast to avoid misinterpretation due to physiological food-induced elevated concentrations of nonprotein nitrogen substances.

  5. Differences in postmortem urea nitrogen, creatinine and uric acid levels between blood and pericardial fluid in acute death.

    PubMed

    Zhu, Bao-Li; Ishikawa, Takaki; Michiue, Tomomi; Tanaka, Sayaka; Zhao, Dong; Li, Dong-Ri; Quan, Li; Oritani, Shigeki; Maeda, Hitoshi

    2007-05-01

    Previous studies showed significant differences in postmortem urea nitrogen (UN), creatinine (Cr) and uric acid (UA) levels in heart blood depending on the causes of death, including acute death. In addition, the levels in pericardial fluid approximated the clinical serum reference ranges, and their elevations may be assessed based on clinical criteria. The present study investigated difference between blood and pericardial levels of these markers. Medicolegal autopsy cases (n=556, within 48h postmortem) of the following causes of death were examined: injury (n=136), asphyxiation (n=50), drowning (n=39), fire fatalities (n=99), hyperthermia (n=11), hypothermia (n=8), poisoning (n=26), delayed traumatic death (n=44) and natural diseases (n=143). When serum UN, Cr and UA levels were compared with the pericardial levels, there was an equivalency for delayed traumatic death and chronic renal failure, although each level was markedly elevated. Parallel increases in serum and pericardial UA and/or Cr levels were also observed for hypothermia and gastrointestinal bleeding. However, in drowning cases, the left cardiac and pericardial UN levels were lower than the right cardiac and peripheral levels, suggesting the influence of water aspiration. Significant elevations in serum and pericardial Cr and UA levels with a higher serum/pericardial UA ratio for fatal methamphetamine intoxication suggest progressive skeletal muscle damage due to advanced hypoxia/acidosis. Similar findings were often observed for other acute and subacute deaths. These findings suggest that a comparison between blood and pericardial nitrogenous compounds would be useful for investigating the cause and process of death.

  6. Binding studies of creatinine and urea on iron-nanoparticle.

    PubMed

    Banerji, Biswadip; Pramanik, Sumit Kumar

    2015-01-01

    Kidney diseases are complicated and can be fatal. Dialysis and transplantation are the only survival solutions to the patients suffering from kidney failures. Both hemodialysis and peritoneal dialysis are risky, due to the possibility of infection and these are expensive and time consuming. The development of simple and reliable technique for the clearance of creatinine and urea from the body is an important part of biotechnology. We have synthesized an iron nanoparticle (INP) and studied its binding with creatinine and urea. The DLS, TEM, AFM, FT-IR and Powder-XRD studies demonstrate strong binding of creatinine and urea to the nanoparticles. This finding may be helpful if it is used in the dialysis technologies. The proposed method may substantially decrease dialysis time and improve its quality in terms of urea and creatinine clearances.

  7. Quantifying creatinine and urea in human urine through Raman spectroscopy aiming at diagnosis of kidney disease

    NASA Astrophysics Data System (ADS)

    Saatkamp, Cassiano Junior; de Almeida, Maurício Liberal; Bispo, Jeyse Aliana Martins; Pinheiro, Antonio Luiz Barbosa; Fernandes, Adriana Barrinha; Silveira, Landulfo, Jr.

    2016-03-01

    Due to their importance in the regulation of metabolites, the kidneys need continuous monitoring to check for correct functioning, mainly by urea and creatinine urinalysis. This study aimed to develop a model to estimate the concentrations of urea and creatinine in urine by means of Raman spectroscopy (RS) that could be used to diagnose kidney disease. Midstream urine samples were obtained from 54 volunteers with no kidney complaints. Samples were subjected to a standard colorimetric assay of urea and creatinine and submitted to spectroscopic analysis by means of a dispersive Raman spectrometer (830 nm, 350 mW, 30 s). The Raman spectra of urine showed peaks related mainly to urea and creatinine. Partial least squares models were developed using selected Raman bands related to urea and creatinine and the biochemical concentrations in urine measured by the colorimetric method, resulting in r=0.90 and 0.91 for urea and creatinine, respectively, with root mean square error of cross-validation (RMSEcv) of 312 and 25.2 mg/dL, respectively. RS may become a technique for rapid urinalysis, with concentration errors suitable for population screening aimed at the prevention of renal diseases.

  8. Quantifying creatinine and urea in human urine through Raman spectroscopy aiming at diagnosis of kidney disease

    NASA Astrophysics Data System (ADS)

    Saatkamp, Cassiano Junior; de Almeida, Maurício Liberal; Bispo, Jeyse Aliana Martins; Pinheiro, Antonio Luiz Barbosa; Fernandes, Adriana Barrinha; Silveira, Landulfo, Jr.

    2016-03-01

    Due to their importance in the regulation of metabolites, the kidneys need continuous monitoring to check for correct functioning, mainly by urea and creatinine urinalysis. This study aimed to develop a model to estimate the concentrations of urea and creatinine in urine by means of Raman spectroscopy (RS) that could be used to diagnose kidney disease. Midstream urine samples were obtained from 54 volunteers with no kidney complaints. Samples were subjected to a standard colorimetric assay of urea and creatinine and submitted to spectroscopic analysis by means of a dispersive Raman spectrometer (830 nm, 350 mW, 30 s). The Raman spectra of urine showed peaks related mainly to urea and creatinine. Partial least squares models were developed using selected Raman bands related to urea and creatinine and the biochemical concentrations in urine measured by the colorimetric method, resulting in r=0.90 and 0.91 for urea and creatinine, respectively, with root mean square error of cross-validation (RMSEcv) of 312 and 25.2 mg/dL, respectively. RS may become a technique for rapid urinalysis, with concentration errors suitable for population screening aimed at the prevention of renal diseases.

  9. Creatinine

    MedlinePlus

    ... Results from creatinine tests may be used in calculations that help assess kidney function: Blood creatinine measurements, ... seen with conditions that result in decreased muscle mass. Levels of 24-hour urine creatinine are evaluated ...

  10. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Development and validation of a simple determination of urine metabolites (oxalate, citrate, uric acid and creatinine) by capillary zone electrophoresis.

    PubMed

    Muñoz, Jose A; López-Mesas, Montserrat; Valiente, Manuel

    2010-04-15

    Oxalate, citrate, uric acid and creatinine are important urine markers for the evaluation and treatment of urolithiasic patients. They have been traditionally analysed by enzymatic and chromatographic techniques which present practical drawbacks, mainly in the sample pre-treatment step. The purpose of this study was to evaluate those markers in urine samples, by an easy multi-analyte assay using capillary zone electrophoresis. The four urine metabolites were determined, at 25 degrees C, by using a 50 cm x 75 microm capillary in 50 mmol l(-1) phosphate buffer (pH 6.5), at constant voltage of -30 kV and UV detection at 195 nm (for oxalate and citrate) or 30 kV and 234 nm (for creatinine and uric acid). The sample pre-treatment was minimum, 5- and 20-fold dilution of the urine sample and acidification to pH 3-4. Validation parameters (linear range, sensitivity, accuracy, precision and detection limits) were statistically comparable to those obtained with the official methods normally used in the clinical practice. The effect of freezing as a conservation method of urine samples is also discussed in terms of recoveries of the analytes. The analytical method developed is highly useful as a diagnostic tool for detecting metabolic renal disorders due to its simplicity, time consuming, easy automation, cost efficiency and analytical effectiveness, accomplishing with the clinical requirements.

  13. Urinary Uric Acid/Creatinine Ratio as a Marker of Mortality and Unfavorable Outcome in NICU-Admitted Neonates

    PubMed Central

    Nariman, Shahin; Mosayebi, Ziba; Sagheb, Setareh; Rastad, Hadith; Hosseininodeh, Seyyed Saeed

    2016-01-01

    Background The survival of neonates who have been admitted to the NICU, especially premature infants with few mortality and morbidity, is the most important attitude. Objectives We presumed whether urinary uric acid/creatinine (UUA/Cr) ratio can be a marker of mortality and adverse outcome in neonates which were admitted to the NICU. Patients and Methods All preterm infants admitted to our NICU after birth from March 2014 to April 2015 were enrolled in this prospective cohort study. UUA/Cr was measured during the first day of life. The severity of diseases (indicated by the need for high set-up of mechanical ventilation, complications of prematurity, and duration of stay in the NICU) and neonatal death were considered to be the final unfavorable outcomes. The relationship between the Log-transformation (Ln) urinary uric acid/creatinine ratio and the Apgar score at the first and 5th minute after birth and the duration of stay were analyzed by using linear regression. Statistical analysis was done by using STATA version 11 (STATA Corp, TX, USA). A P < 0.05 was considered to be statistically significant. Results A total of 362 preterm infants with a mean gestational age of 32.7 (± 3.9) weeks were admitted to the NICU, out of whom 64 (17.6%) had severe disease and 43 (11.8%) died. The mean UUA/Cr ratio was significantly higher in the admitted neonates (3.30 ± 1.95 vs. 1.36 ± 0.42. P = 0.0001). There was a negative correlation between the UUA/Cr ratio and the 1-minute Apgar score (r = -0.17, P = 0.006) and the 5-minute Apgar score (r = -0.19, P = 0.003). The 1-minute Apgar scores were negatively correlated with the outcome (OR = 0.68; P < 0.001) and the duration of stay (β = -.28; P < 0.001). There was no significant correlation between 5-minute Apgar scores and the outcome. There was a significant positive correlation between the UUA/Cr ratio and an unfavorable outcome (OR = 1.24; CI %95: 1.06 to 1.43, P = 0.006) and increasing duration of stay (β = 0.17; P = 0

  14. 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 ± 3.4 mAM(-1)cm(-2) for the creatinine biosensor and 112 ± 3.36 mAM(-1)cm(-2) for the urea biosensor, with apparent Michaelis-Menten constants (KM,app), obtained from the creatinine and urea calibration curves, of 0.163 mM for creatinine deaminase and 0.139 mM for urease, respectively. The biosensors responded linearly over the concentration range 1-125 µM, with a limit of detection of 0.5 µM 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.

  15. Estimating the concentration of urea and creatinine in the human serum of normal and dialysis patients through Raman spectroscopy.

    PubMed

    de Almeida, Maurício Liberal; Saatkamp, Cassiano Junior; Fernandes, Adriana Barrinha; Pinheiro, Antonio Luiz Barbosa; Silveira, Landulfo

    2016-09-01

    Urea and creatinine are commonly used as biomarkers of renal function. Abnormal concentrations of these biomarkers are indicative of pathological processes such as renal failure. This study aimed to develop a model based on Raman spectroscopy to estimate the concentration values of urea and creatinine in human serum. Blood sera from 55 clinically normal subjects and 47 patients with chronic kidney disease undergoing dialysis were collected, and concentrations of urea and creatinine were determined by spectrophotometric methods. A Raman spectrum was obtained with a high-resolution dispersive Raman spectrometer (830 nm). A spectral model was developed based on partial least squares (PLS), where the concentrations of urea and creatinine were correlated with the Raman features. Principal components analysis (PCA) was used to discriminate dialysis patients from normal subjects. The PLS model showed r = 0.97 and r = 0.93 for urea and creatinine, respectively. The root mean square errors of cross-validation (RMSECV) for the model were 17.6 and 1.94 mg/dL, respectively. PCA showed high discrimination between dialysis and normality (95 % accuracy). The Raman technique was able to determine the concentrations with low error and to discriminate dialysis from normal subjects, consistent with a rapid and low-cost test. PMID:27393683

  16. 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 μg mL(-1), respectively. The orange juices contain AA over 212 μg mL(-1).

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

    PubMed

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

    2010-11-01

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

  18. [Simultaneous determination of creatinine, pseudouridine and uric acid in serum and urine by high performance liquid chromatography].

    PubMed

    Peng, Z; Wang, C; Li, C; Gao, Q; Wang, Z; Zhang, G; Zhang, J; Li, X; Peng, J

    1998-03-01

    In this paper a sensitive, rapid and simple HPLC method for the simultaneous determination of creatinine (Cr), pseudouridine (Pu) and uric acid(UA) has been established. We have evaluated clinical value of the method in the early diagnosis of diabetic nephropathy (DN). Separation was obtained using Shim-pack CLC-ODS 15 x 0.6 cm column and mobile phase of buffer solution of phosphate (pH 3.0, 0.02 mol/L) with flow rate of 1 mL/min. Detection was performed with UV detector at an automatic adjustment of wavelength. The recoveries of Cr, Pu and UA were 101.4%, 104.9% and 105.0% respectively. The calibration curves were linear within the concentration range of 8.6-274.6 mumol/L for Cr, 0.72-22.93 mumol/L for Pu and 19.1-612.7 mumol/L for UA (n = 6, r > 0.999, p < 0.01). The CV for within day and between day measurements were < 2.5% and < 5.0% respectively. In addition, Pu, Cr and UA were simultaneously determined in serum and urine of 39 patients with diabetic mellitus (DM). 15 patients with nephrotic syndrome (NS) and 53 normal subjects by the method. Results include: 1. the levels of serum Pu in all DM patients (100%) with microalbuminuria (MiAU) and macroalbuminuria (MaAU) were greater than maximum of normal subjects (X + 2S). In addition, in 9 DM patients (41%) with normal albuminuria (NAU) the levels were also greater than the maximum. 2. In patients with DM, there was no correlation between the serum Pu and the urinary albumin excretion (UAE), whereas the serum Pu correlated closely with the serum Cr. However, the incidence for serum Pu increase was significantly greater in patients. 3. The levels of serum Pu in patients with NS were greater than those in control subjects and patients with DM. Conclusion is that the determination of serum Pu could be used as sensitivity index for the early diagnosis of DN.

  19. Effects of the Hydration State on the Mid-Infrared Spectra of Urea and Creatinine in Relation to Urine Analyses.

    PubMed

    Oliver, Katherine V; Maréchal, Amandine; Rich, Peter R

    2016-06-01

    When analyzing solutes by Fourier transform infrared (FT-IR) spectroscopy in attenuated total reflection (ATR) mode, drying of samples onto the ATR crystal surface can greatly increase solute band intensities and, therefore, aid detection of minor components. However, analysis of such spectra is complicated by the existence of alternative partial hydration states of some substances that can significantly alter their infrared signatures. This is illustrated here with urea, which is a dominant component of urine. The effects of hydration state on its infrared spectrum were investigated both by incubation in atmospheres of fixed relative humidities and by recording serial spectra during the drying process. Significant changes of absorption band positions and shapes were observed. Decomposition of the CN antisymmetric stretching (νas) band in all states was possible with four components whose relative intensities varied with hydration state. These correspond to the solution (1468 cm(-1)) and dry (1464 cm(-1)) states and two intermediate (1454 cm(-1) and 1443 cm(-1)) forms that arise from specific urea-water and/or urea-urea interactions. Such intermediate forms of other compounds can also be formed, as demonstrated here with creatinine. Recognition of these states and their accommodation in analyses of materials such as dried urine allows more precise decomposition of spectra so that weaker bands of diagnostic interest can be more accurately defined.

  20. Differences in Blood Urea and Creatinine Concentrations in Earthed and Unearthed Subjects during Cycling Exercise and Recovery.

    PubMed

    Sokal, Paweł; Jastrzębski, Zbigniew; Jaskulska, Ewelina; Sokal, Karol; Jastrzębska, Maria; Radzimiński, Lukasz; Dargiewicz, Robert; Zieliński, Piotr

    2013-01-01

    Contact of humans with the earth, either directly (e.g., with bare feet) or using a metal conductor, changes their biochemical parameters. The effects of earthing during physical exercise are unknown. This study was carried out to evaluate selected biochemical parameters in subjects who were earthed during cycling. In a double-blind, crossover study, 42 participants were divided into two groups and earthed during exercise and recovery. One group was earthed in the first week during 30 minutes of cycling exercise and during recovery, and a second group was earthed in the second week. A double-blind technique was applied. Blood samples were obtained before each training session, after 15 and 30 minutes of exercise, and after 40 minutes of recovery. Significantly lower blood urea levels were observed in subjects earthed during exercise and relaxation. These significant differences were noted in both groups earthed at the beginning of exercise (P < 0.0001), after 15 (P < 0.0001) and 30 minutes (P < 0.0001) of exercise, and after 40 minutes of relaxation (P < 0.0001). Creatinine concentrations in earthed subjects during exercise were unchanged. Conclusions. Earthing during exercise lowers blood urea concentrations and may inhibit hepatic protein catabolism or increase renal urea excretion. Exertion under earthing may result in a positive protein balance. PMID:24066011

  1. Pharmacogenetic effects of angiotensin-converting enzyme inhibitors over age-related urea and creatinine variations in patients with dementia due to Alzheimer disease

    PubMed Central

    Berretta, Juliana Marília; Suchi Chen, Elizabeth; Cardoso Smith, Marilia; Ferreira Bertolucci, Paulo Henrique

    2016-01-01

    Background: Renal function declines according to age and vascular risk factors, whereas few data are available regarding genetically-mediated effects of anti-hypertensives over renal function. Objective: To estimate urea and creatinine variations in dementia due to Alzheimer disease (AD) by way of a pharmacogenetic analysis of the anti-hypertensive effects of angiotensin-converting enzyme inhibitors (ACEis). Methods: Consecutive outpatients older than 60 years-old with AD and no history of kidney transplant or dialytic therapy were recruited for prospective correlations regarding variations in fasting blood levels of urea and creatinine in one year, considering ACE genotypes of rs1800764 and rs4291 and their respective haplotypes, and treatment with ACEis along with blood pressure variations. Results: For 190 patients, 152 had arterial hypertension, and 122 used ACEis. Minor allele frequencies were 0.492 for rs1800764-C and 0.337 for rs4291-T, both in Hardy-Weinberg equilibrium. There were no overall significant yearly variations in levels of urea and creatinine, but their concurrent variations were positively correlated (ρ <0.0001). Each A allele of rs4291 led to an yearly urea increase of 3,074 mg/dL, and an yearly creatinine increase of 0.044 mg/dL, while the use of ACEis was protective regarding creatinine variations. The use of ACEis was also protective for carriers of rs1800764-CT/rs4291-AA, while carriers of rs1800764-CT/rs4291-AT had steeper reductions in creatinine levels, particularly when they were treated with ACEis. Conclusions: Effects of ACEis over creatinine variations are genetically mediated and independent of blood pressure variations in older people with AD. PMID:27546928

  2. [Studies on the renal handling of urea nitrogen, creatinine, water and electrolytes in hyperthyroid patients with Graves' disease].

    PubMed

    Shirota, T

    1991-05-20

    To delineate the pathophysiological basis for increased blood urea nitrogen (BUN), decreased serum creatinine (SCr) and increased BUN/SCr ratio in patients with hyperthyroidism due to Graves' disease, systematic evaluation on renal handling of solutes and water was carried out before and during treatment of the disease. First, BUN, SCr, serum sodium (Na), serum potassium (K), serum chloride (Cl), creatine kinase (CK), serum triiodothyronine (T3) and serum thyroxine (T4) were consecutively measured in 16 patients (aged 18-62 yrs, 4 males and 12 females) with Graves' disease before and during antithyroid drug therapy, and 16 healthy subjects (aged 22-64 yrs, 4 males and 12 females) served as controls. BUN (14.8 +/- 2.9 mg/100ml) was significantly higher (p less than 0.01), and SCr (0.62 +/- 0.16 mg/100ml) and CK (41.7 +/- 23.6 U/l) were significantly lower (p less than 0.01) in untreated patients compared to respective values in the control group (BUN, 13.2 +/- 2.9 mg/100ml; SCr, 0.87 +/- 0.16 mg/100ml; CK, 99.3 +/- 49.5 U/l). Consequently, BUN/SCr ratio was significantly elevated (p less than 0.01) in the patients. As T4 and T3 returned to normal, BUN, SCr, BUN/SCr ratio and CK of the patients also normalized. Serum electrolytes were not significantly different in the patients compared to the controls. Second, renal clearance of para-aminohippurate (CPAH), inulin (CIn), creatinine (CCr), free water (CH2O) and chloride (CCl) was evaluated in 7 untreated patients (aged 17-44 yrs, 4 males and 3 females) and in 7 controls (aged 24-39 yrs, 5 males and 2 females). In patients with untreated Graves' disease, CPAH, CCr and Curea were significantly greater than in the controls (847 +/- 367 vs 442 +/- 124 ml/min, p less than 0.05, 132.7 +/- 14.7 vs 76.6 +/- 14.4 ml/min, p less than 0.01, and 86.9 +/- 16.0 ml/min vs 52.1 +/- 12.6 ml/min, p less than 0.05, respectively). CIn was slightly but insignificantly increased in the patients (95.3 +/- 20.8 ml/min) compared to the

  3. Interrelationship of βeta-2 microglobulin, blood urea nitrogen and creatinine in streptozotocin-induced diabetes mellitus in rabbits

    PubMed Central

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

    2014-01-01

    Measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) are used as indicators of glomerular filtration rate. The increased levels of these biomarkers are usually detectable at advanced stages of kidney complications. The aim of this study was to find the interrelationship of beta-2 microglobulin (β2M), BUN and Cr in streptozotocin (STZ)-induced diabetes mellitus in rabbits. Diabetes was induced by a single intraperitoneal (IP) injection of 65 mg kg-1 of STZ in rabbits. The levels of serum insulin, glucose and three above mentioned biomarkers were measured one day before (day -1) and on days 1-3 after injection of STZ and continued weekly to the end of the experiment (12 weeks). A statistically significant increase of serum β2M, BUN, Cr and glucose levels, and a significant decrease of insulin levels were observed in diabetic animals. However, β2M levels increased as early as one day after STZ injection compared to Cr and BUN that elevated at day two, suggesting a probable diagnostic advantage of β2M over currently used biomarkers in diabetic related kidney complications. PMID:25568686

  4. [Serum uric acid levels and risk of developing preeclampsia].

    PubMed

    Corominas, Ana I; Balconi, Silvia M; Palermo, Mario; Maskin, Bernardo; Damiano, Alicia E

    2014-01-01

    It is well known that preeclampsia is associated to high uric acid levels, but the clinical assessment of this relationship is still under consideration. Our research was to evaluate if periodic doses of uric acid during pregnancy might help to identify a high risk group prior to the onset of preeclampsia. We conducted a retrospective investigation in 79 primary gestates with normal blood pressure and 79 women with preeclampsia who were assisted at Hospital Nacional Posadas during 2010. Serum uric acid levels, creatininemia, uremia, and proteinuria data from the clinical records of the pregnant women were considered. Uric acid levels were similar in both groups during the first half of gestation. However, as of the 20th week, uric acid increased 1.5-times in preeclamptic women with no changes in creatinine and urea, confirming that these patients had no renal complications. Furthermore, we noted that higher levels of uric acid correlated with low birth weight. We also observed that pregnant women with a family history of hypertension were more likely to develop this condition. Moreover, we did not find a direct relationship with the fetal sex or the appearance of clinical symptoms. The analytical evidence suggests that changes in uric acid concentrations may be due to metabolic alterations at the initial stages of preeclampsia. Therefore, we propose that monitoring levels of uric acid during pregnancy might contribute to the early control of this condition.

  5. Validation of a multi-analyte HPLC-DAD method for determination of uric acid, creatinine, homovanillic acid, niacinamide, hippuric acid, indole-3-acetic acid and 2-methylhippuric acid in human urine.

    PubMed

    Remane, Daniela; Grunwald, Soeren; Hoeke, Henrike; Mueller, Andrea; Roeder, Stefan; von Bergen, Martin; Wissenbach, Dirk K

    2015-08-15

    During the last decades exposure sciences and epidemiological studies attracts more attention to unravel the mechanisms for the development of chronic diseases. According to this an existing HPLC-DAD method for determination of creatinine in urine samples was expended for seven analytes and validated. Creatinine, uric acid, homovanillic acid, niacinamide, hippuric acid, indole-3-acetic acid, and 2-methylhippuric acid were separated by gradient elution (formate buffer/methanol) using an Eclipse Plus C18 Rapid Resolution column (4.6mm×100mm). No interfering signals were detected in mobile phase. After injection of blank urine samples signals for the endogenous compounds but no interferences were detected. All analytes were linear in the selected calibration range and a non weighted calibration model was chosen. Bias, intra-day and inter-day precision for all analytes were below 20% for quality control (QC) low and below 10% for QC medium and high. The limits of quantification in mobile phase were in line with reported reference values but had to be adjusted in urine for homovanillic acid (45mg/L), niacinamide 58.5(mg/L), and indole-3-acetic acid (63mg/L). Comparison of creatinine data obtained by the existing method with those of the developed method showing differences from -120mg/L to +110mg/L with a mean of differences of 29.0mg/L for 50 authentic urine samples. Analyzing 50 authentic urine samples, uric acid, creatinine, hippuric acid, and 2-methylhippuric acid were detected in (nearly) all samples. However, homovanillic acid was detected in 40%, niacinamide in 4% and indole-3-acetic acid was never detected within the selected samples.

  6. 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

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

    PubMed Central

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

    2014-01-01

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

  8. Comparison of measurements of canine plasma creatinine, glucose, proteins, urea, alanine aminotransferase, and alkaline phosphatase obtained with Spotchem SP 4430 and Vitros 250 analyzers.

    PubMed

    Trumel, C; Diquélou, A; Germain, C; Palanché, F; Braun, J P

    2005-12-01

    The suitability of the Spotchem 4430 benchtop biochemistry analyzer for canine blood samples was tested for creatinine, glucose, proteins, urea, alkaline phosphatases and alanine aminotransferase. Results obtained from whole blood and corresponding heparin plasma were identical except for proteins which were higher in plasma (n=10). Between series imprecision (n=10) was <5% for substrates and <10% for enzymes. Comparison of results from 100 Li-heparin samples with those measured with a Vitros 250 analyzer showed good correlation (r>0.93). The slopes of the Passing-Bablock's regression ranged from 0.90 to 1.20 and intercepts were low. The mean biases were low, except for creatinine for which the results obtained by Spotchem (Jaffe reaction) were about 20 micromol/L higher than with the Vitros (enzymatic reaction). The results of this study show that the Spotchem analyzer is suitable for use in canine whole blood or plasma when small numbers of tests are to be performed and large analyzers are not available. PMID:16054888

  9. 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

  10. Associations among Lead Dose Biomarkers, Uric Acid, and Renal Function in Korean Lead Workers

    PubMed Central

    Weaver, Virginia M.; Jaar, Bernard G.; Schwartz, Brian S.; Todd, Andrew C.; Ahn, Kyu-Dong; Lee, Sung-Soo; Wen, Jiayu; Parsons, Patrick J.; Lee, Byung-Kook

    2005-01-01

    Recent research suggests that both uric acid and lead may be nephrotoxic at lower levels than previously recognized. We analyzed data from 803 current and former lead workers to determine whether lead biomarkers were associated with uric acid and whether previously reported associations between lead dose and renal outcomes were altered after adjustment for uric acid. Outcomes included uric acid, blood urea nitrogen, serum creatinine, measured and calculated creatinine clearances, and urinary N-acetyl-β-d-glucosaminidase (NAG) and retinol-binding protein. Mean (± SD) uric acid, tibia lead, and blood lead levels were 4.8 ± 1.2 mg/dL, 37.2 ± 40.4 μg/g bone mineral, and 32.0 ± 15.0 μg/dL, respectively. None of the lead measures (tibia, blood, and dimercaptosuccinic-acid–chelatable lead) was associated with uric acid, after adjustment for age, sex, body mass index, and alcohol use. However, when we examined effect modification by age on these relations, both blood and tibia lead were significantly associated (β= 0.0111, p < 0.01 and β= 0.0036, p = 0.04, respectively) in participants in the oldest age tertile. These associations decreased after adjustment for blood pressure and renal function, although blood lead remained significantly associated with uric acid (β= 0.0156, p = 0.01) when the population was restricted to the oldest tertile of workers with serum creatinine greater than the median (0.86 mg/dL). Next, in models of renal function in all workers, uric acid was significantly (p < 0.05) associated with all renal outcomes except NAG. Finally, in the oldest tertile of workers, associations between lead dose and NAG were unchanged, but fewer associations between the lead biomarkers and the clinical renal outcomes remained significant (p ≤0.05) after adjustment for uric acid. In conclusion, our data suggest that older workers comprise a susceptible population for increased uric acid due to lead. Uric acid may be one, but not the only, mechanism for

  11. Investigation of the efficacy of 99 mTc-DTPA scintigraphic GFR measurement with Gates method in the detection of cisplatin-induced nephrotoxicity in comparison with plasma urea and creatinine measurement.

    PubMed

    Özülker, Filiz; Özülker, Tamer; Uzun, Aysun Küçüköz; Özpaçacı, Tevfik

    2011-12-01

    In this study, we investigated the efficacy of 99mTc-DTPA scintigraphic analysis of GFR with the Gates method in comparison with the measurement of plasma urea and creatinine, in the detection of nephrotoxicity occurred in patients treated with cisplatin.Twenty-six male patients with a mean age of 26.73±6.39 years (age range 15-42) who had seminomatous and nonseminomatous testicular carcinoma were included in our study. The patients received cisplatin with a dose of 20 mg/m2 per day for five consecutive days repeated every 21 days. Before starting chemotherapy, immediately after the end of four cycles of chemotherapy and 7 months after the beginning of chemotherapy, plasma urea and creatinine levels were measured and simultaneously scintigraphic GFR estimation using 99 mTc-DTPA with the Gates method was performed. In the measurements done immediately after the chemotherapy, in 18 of the 26 patients GFR levels decreased, in 4 of the 8 remaining patients GFR did not change, and in 4 patients there was an increase in the GFR levels. The changes in the averages of the plasma urea and creatinine levels between measurements done before and after the chemotherapy were not statistically significant. The decrease in the average of the GFR values immediately after chemotherapy, in comparison to the average of GFR values measured before chemotherapy, was found to be statistically significant with paired sample t test analysis (P<0.009 with 95% CI). We concluded that scintigraphic GFR measurement using the Gates method with 99mTc-DTPA is a suitable method in the diagnosis of nephrotoxicity occuring due to cisplatine.

  12. 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.

  13. MedlinePlus: Creatinine

    MedlinePlus

    ... Kidney Diseases Resources Creatinine (American Association for Clinical Chemistry) Creatinine - blood Also in Spanish Creatinine - urine Also ... and Albumin/ Creatinine Ratio (American Association for Clinical Chemistry) Urine Protein and Urine Protein to Creatinine Ratio ( ...

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

    PubMed

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

    2015-01-01

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

  15. 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 ...

  16. Colorimetric Detection of Creatinine Based on Plasmonic Nanoparticles via Synergistic Coordination Chemistry.

    PubMed

    Du, Jianjun; Zhu, Bowen; Leow, Wan Ru; Chen, Shi; Sum, Tze Chien; Peng, Xiaojun; Chen, Xiaodong

    2015-09-01

    A simple and portable colorimetric assay for creatinine detection is fabricated based on the synergistic coordination of creatinine and uric acid with Hg(2+) on the surface of gold nanoparticles, which exhibits good selectivity and sensitivity. Point-of-care clinical creatinine monitoring can be supported for monitoring renal function and diagnosing corresponding renal diseases at home.

  17. Creatinine clearance test

    MedlinePlus

    Creatinine is a chemical waste product of creatine. Creatine is a chemical the body makes to supply energy, mainly to muscles. By comparing the creatinine level in urine with the creatinine level in blood , this test estimates the ...

  18. Creatinine urine test

    MedlinePlus

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

  19. 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 , ...

  20. Distribution of creatinine following intravenous and oral administration to rats.

    PubMed

    Watanabe, J; Hirate, J; Iwamoto, K; Ozeki, S

    1981-05-01

    To evaluate the distribution of creatinine in rats, urinary, fecal and expiratory excretion, plasma levels and whole-body autoradiography following intravenous or oral administration of [carbonyl-14C]creatinine was investigated. More than 90% of the exogeneous creatinine was excreted in the urine in 24 hr following intravenous administration, and both fecal and expiratory excretion were only about 1%. In case of oral administration, however, it was found that expiratory excretion could not be neglected, ranging from about 1 to 30%. Plasma creatinine concentration-time curves following the intravenous administration (70.4 micrograms/kg or 400 mg/kg as creatinine) were analyzed according to a two-compartment open model. There were significant but very small differences in the pharmacokinetic parameters for these two doses. When these parameters were compared with those of urea, k12 and k21, which are transfer rate constants between compartment 1 and 2, for creatinine were significantly smaller than those of urea. On the other hand, k10 was larger in creatinine. Furthermore, (V'd)extrap for creatinine was about three times that of urea. Whole-body autoradiograms at 5 minutes following intravenous administration showed that exogeneous creatinine distributes with higher concentrations in liver, lung and kidney than in muscle and fat. This results was remarkably different from that of urea which distributes almost uniformly throughout the body at the same time. This difference observed in the autoradiograms would be the consequence of the fact that urea has larger k12 and k21 than creatinine.

  1. Creatinine blood test

    MedlinePlus

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

  2. Uric acid - blood

    MedlinePlus

    ... High levels of uric acid can sometimes cause gout or kidney disease. You may have this test if you have had or are about to have certain types of chemotherapy. Rapid weight loss, which may occur with such treatments, can increase the amount of uric acid in ...

  3. Uric acid and hypertension.

    PubMed

    Feig, Daniel I

    2011-09-01

    A link between serum uric acid and the development of hypertension was first hypothesized in the 1870s. Although numerous epidemiologic studies in the 1980s and 1990s suggested an association, relatively little attention was paid to it until recently. Animal models have suggested a two-step pathogenesis by which uric acid initially activates the renin angiotensin system and suppresses nitric oxide, leading to uric acid-dependent increase in systemic vascular resistance, followed by a uric acid-mediated vasculopathy, involving renal afferent arterioles, resulting in a late sodium-sensitive hypertension. Initial clinical trials in young patients have supported these mechanisms in young patients but do not yet support pharmacologic reduction of serum uric acid as first-line therapy for hypertension.

  4. Four-week effects of allopurinol and febuxostat treatments on blood pressure and serum creatinine level in gouty men.

    PubMed

    Kim, Hyun Ah; Seo, Young-Il; Song, Yeong W

    2014-08-01

    The aim of this study was to observe the effects of uric acid lowering therapy (UALT), febuxostat and allopurinol, on blood pressure (BP) and serum creatinine level. Post-hoc data were derived from a phase-III, randomised, double-blind, 4-week trial of male gouty patients that compared the safety and efficacy of febuxostat and allopurinol in adults with gout. The subjects were randomly assigned to one of five groups, 35-37 in each group (febuxostat: 40, 80, 120 mg/d; allopurinol: 300 mg/d; control group: placebo). Blood pressure and serum creatinine level were measured at baseline and at weeks 2 and 4. Diastolic BP and creatinine level had decreased significantly in the UALT groups compared to the control group at week 4. Diastolic BP had decreased significantly in the allopurinol group and serum creatinine level had decreased significantly in the febuxostat groups at week 4. After adjusting for confounding variables, serum uric acid changes were found to be significantly correlated with changes in serum creatinine level but were not associated with changes in systolic or diastolic BP. UALT in gouty subjects significantly decreased diastolic BP and serum creatinine level. Changes in uric acid were significantly correlated with those in serum creatinine level, suggesting the feasibility of renal function improvement through UALT in gouty men.

  5. 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.

  6. Serum creatinine concentration at the onset of uremia: higher levels in black males.

    PubMed

    Abuelo, J G; Shemin, D; Chazan, J A

    1992-06-01

    We compared serum creatinine and blood urea nitrogen concentrations, estimated creatinine clearances and frequency of uremic symptoms at the start of chronic hemodialysis in all 20 black and 179 white males treated between 1969 and 1983. Serum creatinine concentrations were significantly higher in black males (16.5 +/- 5.9 mg/dl) than in white males (11.7 +/- 4.7 mg/dl; p = 0.016). There were no significant differences in blood urea nitrogen concentration, estimated creatinine clearance and frequency of uremic symptoms between the two groups. Blood urea nitrogen to serum creatinine ratios were lower in black males, (7.3 +/- 1.9) than in white males (11.4 +/- 3.8; p = 0.0001), and only one black male had a ratio greater than 10 compared to 60% of whites. We concluded that black males tend to have higher serum creatinine concentrations than white males at the onset of uremic symptoms, and that higher striated muscle creatinine production in black males and not lower renal function may be the cause.

  7. Imprinted zeolite modified carbon paste electrode as a potentiometric sensor for uric acid

    NASA Astrophysics Data System (ADS)

    Khasanah, Miratul; Widati, Alfa Akustia; Fitri, Sarita Aulia

    2016-03-01

    Imprinted zeolite modified carbon paste electrode (carbon paste-IZ) has been developed and applied to determine uric acid by potentiometry. The imprinted zeolite (IZ) was synthesized by the mole ratio of uric acid/Si of 0.0306. The modified electrode was manufactured by mass ratio of carbon, IZ and solid paraffin was 40:25:35. The modified electrode had shown the measurement range of 10-5 M to 10-2 M with Nernst factor of 28.6 mV/decade, the detection limit of 5.86 × 10-6 M and the accuracy of 95.3 - 105.0%. Response time of the electrode for uric acid 10-5 M - 10-2 M was 25 - 44 s. The developed electrode showed the high selectivity toward uric acid in the urea matrix. Life time of the carbon paste-IZ electrode was 10 weeks.

  8. Serum and Urinary Malondialdehyde (MDA), Uric acid, and Protein as markers of perinatal asphyxia

    PubMed Central

    El Bana, Sawsan Mahmoud; Maher, Sheren Esam; Gaber, Amani Fawzy; Aly, Sanaa Shaker

    2016-01-01

    Introduction Perinatal asphyxia (PA) is among the leading causes of neonatal morbidity and death in neonatal intensive care units (NICUs). The aims of this research were to determine the concentrations of malondialdehyde (MDA), urine MDA, uric acid, and protein in the cord blood of neonates with perinatal asphyxia and to determine their relationship with the severity of perinatal asphyxia. Methods This matched case-control study was conducted from October 2012 to March 2013. All of the cases and controls were selected from the Gynecology & Obstetrics Department and the NICUs, at Qous Central Hospital in Qena, Egypt. We allocated 20 full-term neonates who had perinatal asphyxia to the case group. Also, we selected 20 healthy neonates for the control group. The subjects were matched with respect to age and gender. At birth and 48 hours later, measurements were made of MDA in cord blood and urine, and uric acid, protein, and creatinine also were measured in both groups. The data were analyzed by SPSS, version 17, using the independent-samples t-test, ANOVA, Tukey’s test, and Spearman’s correlation coefficient. Results At birth and 48 hr later, the newborns’ with PA had significantly higher levels of MDA in the cord blood, mean urinary uric acid/creatinine (UUA:Cr), protein/creatinine (UP:Cr), and MDA/creatinine ratio (UMDA:Cr) than the controls; their PA levels were correlated with the degree of hypoxic-ischemic encephalopathy (HIE). The babies who died due to PA had significantly higher levels of cord blood MDA, and they also had higher UUA:Cr, UP:Cr, and UMDA:Cr ratios than the babies who survived. Conclusion The concentration of MDA in cord blood can be used as a diagnostic marker of oxidative stress in asphyxiated neonates. The ratios of the urinary excretion rates of uric acid, protein, and MDA to creatinine increased as the severity of perinatal asphyxia and associated brain damage increased. PMID:27648187

  9. Serum and Urinary Malondialdehyde (MDA), Uric acid, and Protein as markers of perinatal asphyxia

    PubMed Central

    El Bana, Sawsan Mahmoud; Maher, Sheren Esam; Gaber, Amani Fawzy; Aly, Sanaa Shaker

    2016-01-01

    Introduction Perinatal asphyxia (PA) is among the leading causes of neonatal morbidity and death in neonatal intensive care units (NICUs). The aims of this research were to determine the concentrations of malondialdehyde (MDA), urine MDA, uric acid, and protein in the cord blood of neonates with perinatal asphyxia and to determine their relationship with the severity of perinatal asphyxia. Methods This matched case-control study was conducted from October 2012 to March 2013. All of the cases and controls were selected from the Gynecology & Obstetrics Department and the NICUs, at Qous Central Hospital in Qena, Egypt. We allocated 20 full-term neonates who had perinatal asphyxia to the case group. Also, we selected 20 healthy neonates for the control group. The subjects were matched with respect to age and gender. At birth and 48 hours later, measurements were made of MDA in cord blood and urine, and uric acid, protein, and creatinine also were measured in both groups. The data were analyzed by SPSS, version 17, using the independent-samples t-test, ANOVA, Tukey’s test, and Spearman’s correlation coefficient. Results At birth and 48 hr later, the newborns’ with PA had significantly higher levels of MDA in the cord blood, mean urinary uric acid/creatinine (UUA:Cr), protein/creatinine (UP:Cr), and MDA/creatinine ratio (UMDA:Cr) than the controls; their PA levels were correlated with the degree of hypoxic-ischemic encephalopathy (HIE). The babies who died due to PA had significantly higher levels of cord blood MDA, and they also had higher UUA:Cr, UP:Cr, and UMDA:Cr ratios than the babies who survived. Conclusion The concentration of MDA in cord blood can be used as a diagnostic marker of oxidative stress in asphyxiated neonates. The ratios of the urinary excretion rates of uric acid, protein, and MDA to creatinine increased as the severity of perinatal asphyxia and associated brain damage increased.

  10. Recognition and Sensing of Creatinine.

    PubMed

    Guinovart, Tomàs; Hernández-Alonso, Daniel; Adriaenssens, Louis; Blondeau, Pascal; Martínez-Belmonte, Marta; Rius, F Xavier; Andrade, Francisco J; Ballester, Pablo

    2016-02-12

    Current methods for creatinine quantification suffer from significant drawbacks when aiming to combine accuracy, simplicity, and affordability. Here, an unprecedented synthetic receptor, an aryl-substituted calix[4]pyrrole with a monophosphonate bridge, is reported that displays remarkable affinity for creatinine and the creatininium cation. The receptor works by including the guest in its deep and polar aromatic cavity and establishing directional interactions in three dimensions. When incorporated into a suitable polymeric membrane, this molecule acts as an ionophore. A highly sensitive and selective potentiometric sensor suitable for the determination of creatinine levels in biological fluids, such as urine or plasma, in an accurate, fast, simple, and cost-effective way has thus been developed. PMID:26749029

  11. Serum uric acid correlates in elderly men and women with special reference to body composition and dietary intake (Dutch Nutrition Surveillance System).

    PubMed

    Loenen, H M; Eshuis, H; Löwik, M R; Schouten, E G; Hulshof, K F; Odink, J; Kok, F J

    1990-01-01

    In 460 apparently healthy Dutch elderly, aged 65-79 years, serum uric acid correlates were studied by linear regression analyses, for men and women separately. Diuretic therapy, total serum cholesterol (women only) and creatinine clearance (in bivariate analysis only) were significantly associated with serum uric acid level. Positive associations of serum uric acid with body weight, body mass index, body fatness (men) and lean body mass (men) were observed, with and without adjustment for diuretic therapy, creatinine clearance and age. Serum uric acid levels, whether adjusted or not for these variables and for body mass index, were positively associated with alcohol intake (men) and consumption of meat and fish (women), and inversely with consumption of bread, margarine and milk products (women). These results indicate that limited medication with diuretics, weight control and restriction of alcohol use may help to prevent hyperuricemia in the elderly.

  12. Urinary Total Hydroxyproline: Creatinine Ratio

    PubMed Central

    Wharton, B. A.; Gough, G.; Williams, Angela; Kitts, Sheila; Pennock, C. A.

    1972-01-01

    The total hydroxyproline: creatinine ratio has been determined in random samples of urine collected from 1577 normal Bristol children and from children with hypothyroidism, growth hormone deficiency, coeliac disease, and rickets. The results in normal children had a profile similar to that of length velocity. When specific therapy was given to the children with growth failure there was a prompt increase in the total hydroxyproline: creatinine ratio, which occurred well before a growth spurt could be detected by anthropometry. The ratio could be a useful chemical adjunct to anthropometry and radiology in the assessment of normal and abnormal growth. The prompt response of the ratio to changes in growth rate suggests that it may be particularly useful in studying physiological variation in growth over short periods of time and in close monitoring of treatment regimens for growth failure. Random samples of urine may be used, automated methods of analysis are available, and other specialities find the investigation a useful one, so that for the paediatrician the urine total hydroxyproline: creatinine ratio has a potentially wide application. PMID:5018659

  13. 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.

  14. Fructose and uric acid in diabetic nephropathy.

    PubMed

    Bjornstad, Petter; Lanaspa, Miguel A; Ishimoto, Takuji; Kosugi, Tomoki; Kume, Shinji; Jalal, Diana; Maahs, David M; Snell-Bergeon, Janet K; Johnson, Richard J; Nakagawa, Takahiko

    2015-09-01

    Clinical studies have reported associations between serum uric acid levels and the development of diabetic nephropathy, but the underlying mechanisms remain elusive. There is evidence from animal studies that blocking uric acid production protects the kidney from tubulointerstitial injury, which may suggest a causal role for uric acid in the development of diabetic tubular injury. In turn, when fructose, which is endogenously produced in diabetes via the polyol pathway, is metabolised, uric acid is generated from a side-chain reaction driven by ATP depletion and purine nucleotide turnover. For this reason, uric acid derived from endogenous fructose could cause tubulointerstitial injury in diabetes. Accordingly, our research group recently demonstrated that blocking fructose metabolism in a diabetic mouse model mitigated the development of tubulointerstitial injury by lowering tubular uric acid production. In this review we discuss the relationship between uric acid and fructose as a novel mechanism for the development of diabetic tubular injury. PMID:26049401

  15. Fructose and uric acid in diabetic nephropathy

    PubMed Central

    Bjornstad, Petter; Lanaspa, Miguel A.; Ishimoto, Takuji; Kosugi, Tomoki; Kume, Shinji; Jalal, Diana; Maahs, David M.; Snell-Bergeon, Janet K.; Johnson, Richard J.

    2016-01-01

    Clinical studies have reported associations between serum uric acid levels and the development of diabetic nephropathy, but the underlying mechanisms remain elusive. There is evidence from animal studies that blocking uric acid production protects the kidney from tubulointerstitial injury, which may suggest a causal role for uric acid in the development of diabetic tubular injury. In turn, when fructose, which is endogenously produced in diabetes via the polyol pathway, is metabolised, uric acid is generated from a side-chain reaction driven by ATP depletion and purine nucleotide turnover. For this reason, uric acid derived from endogenous fructose could cause tubulointerstitial injury in diabetes. Accordingly, our research group recently demonstrated that blocking fructose metabolism in a diabetic mouse model mitigated the development of tubulointerstitial injury by lowering tubular uric acid production. In this review we discuss the relationship between uric acid and fructose as a novel mechanism for the development of diabetic tubular injury. PMID:26049401

  16. Total saponins from dioscorea septemloba thunb reduce serum uric acid levels in rats with hyperuricemia through OATP1A1 up-regulation.

    PubMed

    Chen, Yan; Chen, Xiao-lin; Xiang, Ting; Sun, Bao-guo; Luo, Hao-xuan; Liu, Meng-ting; Chen, Ze-xiong; Zhang, Shi-jun; Wang, Chang-Jun

    2016-04-01

    The aim of this study is to evaluate the efficacy of total saponins of Dioscorea (TSD), an extract of the Chinese herbal Bi Xie, on hyperuricemia and to elucidate the underlying mechanisms. The rat hyperuricemia model was established by administration of adenine. Thirty-two rats were randomly allocated into 4 groups: model group, low/high-dose TSD-treated groups, and allopurinol-treated group. Meanwhile, 8 rats were used as normal controls. Serum uric acid (UA), blood urea nitrogen (BUN), serum creatinine (Scr), and organic anion transporting polypeptide 1A1 (OATP1A1) levels were measured. Comparison between the model group and treatment (allopurinol and TSD) groups showed the serum UA levels were significantly decreased in treatment groups. TSD had similar effects to allopurinol. It was found that the OATP1A1 protein expression levels in treatment groups were higher than in model group and normal controls. And different from the allopurinol-treated groups, TSD-treated group had elevated OATP1A1 expression levels in the stomach, liver, small intestine and large intestine tissues. It was suggested that TSD may facilitate the excretion of UA and lower UA levels by up-regulating OATP1A1 expression.

  17. Serum Uric Acid Level Predicts Progression of IgA Nephropathy in Females but Not in Males

    PubMed Central

    Shoji, Tatsuya; Shinzawa, Maki; Hasuike, Yukiko; Nagatoya, Katsuyuki; Yamauchi, Atsushi; Hayashi, Terumasa; Kuragano, Takayuki; Moriyama, Toshiki; Isaka, Yoshitaka; Nakanishi, Takeshi

    2016-01-01

    Background Immunoglobulin A nephropathy (IgAN) is one of most common forms of glomerulonephritis. At this point, the clinical impact of hyperuricemia on IgAN is not clear. The aim of the present study was to explore the clinical impact of hyperuricemia on the progression of IgAN. Study Design Multicenter retrospective cohort study. Setting & Participants 935 IgAN patients who were diagnosed by kidney biopsy at Osaka University Hospital, Osaka General Hospital, and Osaka Rosai Hospital. were included in this study. Predictor Uric acid levels at renal biopsy. Outcomes The outcome of interest was the time from the kidney biopsy to the time when a 50% increase in the baseline serum creatinine level was observed, which was defined as "progression". Measurements The baseline characteristics according to the kidney biopsy at the time of diagnosis were collected from the medical records, and included age, gender, body mass index, hypertension, diabetes (use of antidiabetic drugs), serum levels of creatinine, urinary protein, smoking status, RAAS blockers and steroid therapy. Results An elevated serum uric acid level was an independent risk factor for progression in female patients (per 1.0 mg/dL, multivariate-adjusted incident rate ratio 1.33 [95% confidence interval 1.07, 1.64], P = 0.008) but not in male patients (1.02 [0.81, 1.29], P = 0.855). To control a confounding effect of renal function on an association between serum uric acid level and progression in female patients, age- and serum creatinine-matched and propensity score-matched analyses were performed, and these results also supported the effect by uric acid on kidney disease progression independent of basal kidney function. Limitations A cohort analyzed retorospectively. Conclusions This study revealed that an elevated uric acid level was an independent risk factor for ESKD in female IgAN patients. Therefore, uric acid might be a treatable target in female IgAN patients. PMID:27560997

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

    NASA Astrophysics Data System (ADS)

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

    2002-05-01

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

  19. Uric acid transport and disease

    PubMed Central

    So, Alexander; Thorens, Bernard

    2010-01-01

    Uric acid is the metabolic end product of purine metabolism in humans. It has antioxidant properties that may be protective but can also be pro-oxidant, depending on its chemical microenvironment. Hyperuricemia predisposes to disease through the formation of urate crystals that cause gout, but hyperuricemia, independent of crystal formation, has also been linked with hypertension, atherosclerosis, insulin resistance, and diabetes. We discuss here the biology of urate metabolism and its role in disease. We also cover the genetics of urate transport, including URAT1, and recent studies identifying SLC2A9, which encodes the glucose transporter family isoform Glut9, as a major determinant of plasma uric acid levels and of gout development. PMID:20516647

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

    PubMed Central

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

    2011-01-01

    Objectives. SLC2A9 gene variants associate with serum uric acid in white populations, but little is known about African American populations. Since SLC2A9 is a transporter, gene variants may be expected to associate more closely with the fractional excretion of urate, a measure of renal tubular transport, than with serum uric acid, which is influenced by production and extrarenal clearance. Methods. Genotypes of single nucleotide polymorphisms (SNPs) distributed across the SLC2A9 gene were obtained in the Genetic Epidemiology Network of Arteriopathy cohorts. The associations of SNPs with serum uric acid, fractional excretion of urate and urine urate-to-creatinine ratio were assessed with adjustments for age, sex, diuretic use, BMI, homocysteine and triglycerides. Results. We identified SLC2A9 gene variants that were associated with serum uric acid in 1155 African American subjects (53 SNPs) and 1132 white subjects (63 SNPs). The most statistically significant SNPs in African American subjects (rs13113918) and white subjects (rs11723439) were in the latter half of the gene and explained 2.7 and 2.8% of the variation in serum uric acid, respectively. After adjustment for this SNP in African Americans, 0.9% of the variation in serum uric acid was explained by an SNP (rs1568318) in the first half of the gene. Unexpectedly, SLC2A9 gene variants had stronger associations with serum uric acid than with fractional excretion of urate. Conclusions. These findings support two different loci by which SLC2A9 variants affect uric acid levels in African Americans and suggest SLC2A9 variants affect serum uric acid level via renal and extrarenal clearance. PMID:21186168

  1. The Relation between Serum Uric Acid and HbA1c Is Dependent upon Hyperinsulinemia in Patients with Newly Diagnosed Type 2 Diabetes Mellitus

    PubMed Central

    Cui, Yuliang; Bu, Hemei; Zhao, Sha; Li, Xiaona; Lu, Shan

    2016-01-01

    Objective. The aim of our study was to explore the dependent condition of the relationship between uric acid and blood glucose in type 2 diabetes. Research Design and Methods. We measured the HbA1c, serum uric acid, creatinine, lipids profiles, and so forth of 605 newly diagnosed type 2 diabetes patients, and oral glucose tolerance tests (OGTTs) were performed on each patient. The population was divided into high and low insulin groups. Multiple linear regression analyses were conducted to assess the relationship between uric acid and HbA1c. Results. Serum uric acid and HbA1c levels were low in newly diagnosed type 2 diabetes patients. However, we found no significant relationship between uric acid and HbA1c by regression analysis after adjusting total insulin. The concentration of uric acid was inversely correlated with HbA1c in the high insulin group, regardless of patient sex. However, no associations were found in low insulin group. Conclusions. The negative correlation between uric acid and HbA1c is conditional in newly diagnosed type 2 diabetes patients and is related to hyperinsulinemia. Therefore, uric acid is likely only useful as a biomarker of blood glucose in patients exhibiting hyperinsulinemia. PMID:27403443

  2. Uric Acid and Antioxidant Effects of Wine

    PubMed Central

    Boban, Mladen; Modun, Darko

    2010-01-01

    The aim of this article is to review the role of uric acid in the context of antioxidant effects of wine and its potential implication to human health. We described and discussed the mechanisms of increase in plasma antioxidant capacity after consumption of moderate amounts of wine. Because this effect is largely contributed by acute elevation in plasma uric acid, we paid special attention to wine constituents and metabolic processes that are likely to be involved in uric acid elevation. PMID:20162741

  3. Association of Serum Uric Acid Concentration with Diabetic Retinopathy and Albuminuria in Taiwanese Patients with Type 2 Diabetes Mellitus

    PubMed Central

    Liang, Ching-Chao; Lin, Pi-Chen; Lee, Mei-Yueh; Chen, Szu-Chia; Shin, Shyi-Jang; Hsiao, Pi-Jung; Lin, Kun-Der; Hsu, Wei-Hao

    2016-01-01

    Patients with type 2 diabetes mellitus (DM) may experience chronic microvascular complications such as diabetic retinopathy (DR) and diabetic nephropathy (DN) during their lifetime. In clinical studies, serum uric acid concentration has been found to be associated with DR and DN. The goal of this study was to evaluate the relationship between the increases in serum uric acid level and the severity of DR and albuminuria in Taiwanese patients with type 2 DM. We recorded serum uric acid concentration, the severity of DR, and the severity of albuminuria by calculating urinary albumin-to-creatinine ratio (UACR) in 385 patients with type 2 DM. In multivariate logistic regression analysis, a high uric acid concentration was a risk factor for albuminuria (odds ratio (OR), 1.227; 95% confidence interval (CI) = 1.015–1.482; p = 0.034) and DR (OR, 1.264; 95% CI = 1.084–1.473; p = 0.003). We also demonstrated that there was a higher concentration of serum uric acid in the patients with more severe albuminuria and DR. In conclusion, an increased serum uric acid level was significantly correlated with the severity of albuminuria and DR in Taiwanese patients with type 2 DM. PMID:27490538

  4. UREA INFRASTRUCTURE FOR UREA SCR NOX REDUCTION

    SciTech Connect

    Bunting, Bruce G.

    2000-08-20

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

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

    PubMed

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

    2008-01-15

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

  6. Urea metabolism in plants.

    PubMed

    Witte, Claus-Peter

    2011-03-01

    Urea is a plant metabolite derived either from root uptake or from catabolism of arginine by arginase. In agriculture, urea is intensively used as a nitrogen fertilizer. Urea nitrogen enters the plant either directly, or in the form of ammonium or nitrate after urea degradation by soil microbes. In recent years various molecular players of plant urea metabolism have been investigated: active and passive urea transporters, the nickel metalloenzyme urease catalyzing the hydrolysis of urea, and three urease accessory proteins involved in the complex activation of urease. The degradation of ureides derived from purine breakdown has long been discussed as a possible additional metabolic source for urea, but an enzymatic route for the complete hydrolysis of ureides without a urea intermediate has recently been described for Arabidopsis thaliana. This review focuses on the proteins involved in plant urea metabolism and the metabolic sources of urea but also addresses open questions regarding plant urea metabolism in a physiological and agricultural context. The contribution of plant urea uptake and metabolism to fertilizer urea usage in crop production is still not investigated although globally more than half of all nitrogen fertilizer is applied to crops in the form of urea. Nitrogen use efficiency in crop production is generally well below 50% resulting in economical losses and creating ecological problems like groundwater pollution and emission of nitric oxides that can damage the ozone layer and function as greenhouse gasses. Biotechnological approaches to improve fertilizer urea usage bear the potential to increase crop nitrogen use efficiency.

  7. 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.

  8. 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.

  9. Topical urea in dermatology.

    PubMed

    Banerjee, P K; Choudhury, A K; Panja, S K

    1990-03-01

    For years research has been conducted to find a cutaneous moisturizer that is effective, easily available and relatively inexpensive urea, as a atopical agent, is all of this and is also a mild keratolytic. A trial was conducted over 200 patients suffering from a variety of disorders that were selected and using urea topically as urea 10 (10%), urea-20 lotion (20%), Urea-HC (with hydrocartisanl). The agent was applied twice daily for a maximum period of 8 weeks. Results indicate that urea is an effective moisturizer and in promotes the penetration of hydrocelisone into the skin.

  10. 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...

  11. 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...

  12. 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)

  13. 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

  14. Association of Renal Manifestations with Serum Uric Acid in Korean Adults with Normal Uric Acid Levels

    PubMed Central

    Jung, Dong-Hyuk; Lee, Yong-Jae; Lee, Hye-Ree; Lee, Jung-Hyun

    2010-01-01

    Several studies have reported that hyperuricemia is associated with the development of hypertension and cardiovascular disease. Increasing evidences also suggest that hyperuricemia may have a pathogenic role in the progression of renal disease. Paradoxically, uric acid is also widely accepted to have antioxidant activity in experimental studies. We aimed to investigate the association between glomerular filtration rate (GFR) and uric acid in healthy individuals with a normal serum level of uric acid. We examined renal function determined by GFR and uric acid in 3,376 subjects (1,896 men; 1,480 women; aged 20-80 yr) who underwent medical examinations at Gangnam Severance Hospital from November 2006 to June 2007. Determinants for renal function and uric acid levels were also investigated. In both men and women, GFR was negatively correlated with systolic and diastolic blood pressures, fasting plasma glucose, total cholesterol, uric acid, log transformed C reactive protein, and log transformed triglycerides. In multivariate regression analysis, total uric acid was found to be an independent factor associated with estimated GFR in both men and women. This result suggests that uric acid appears to contribute to renal impairment in subjects with normal serum level of uric acid. PMID:21165292

  15. Effect of losartan on serum uric acid in hypertension treated with a diuretic: the COMFORT study.

    PubMed

    Matsumura, Kiyoshi; Arima, Hisatomi; Tominaga, Mitsuhiro; Ohtsubo, Toshio; Sasaguri, Toshiyuki; Fujii, Koji; Fukuhara, Masayo; Uezono, Keiko; Morinaga, Yuki; Ohta, Yuko; Otonari, Takatoshi; Kawasaki, Junya; Kato, Isao; Tsuchihashi, Takuya

    2015-01-01

    It has been shown that losartan, an angiotensin II receptor blocker (ARB), reduces serum uric acid levels. However, the effects of losartan on serum uric acid levels in the patients treated with a thiazide diuretic have not been fully elucidated. We have investigated the effects of losartan compared with other ARBs on blood variables and blood pressure control in hypertensive patients treated with a thiazide diuretic using data from the COMFORT study. The present analysis included a total of 118 hypertensive subjects on combination treatment with ARBs except for losartan and a diuretic who were randomly assigned to a daily regimen of a combination pill (losartan 50 mg/hydrochlorothiazide 12.5 mg) or to continuation of two pills, an ARB except for losartan and a diuretic. Blood pressures were evaluated at 1, 3, and 6 months after randomization and changes in blood variables including serum uric acid were evaluated during 6 months treatment period. Mean follow-up blood pressure levels were not different between the combination pill (losartan treatment) group and the control (ARBs except for losartan) group. On the other hand, serum uric acid significantly decreased in the combination pill group compared with the control group (-0.44 versus + 0.10 mg/dl; p = 0.01), although hematocrit, serum creatinine, sodium and potassium were not different between the groups. These results suggest that the treatment regimen switched from a combination therapy of ARBs except for losartan and a diuretic to a combination pill (losartan/ hydrochlorothiazide) decreases serum uric acid without affecting blood pressure control.

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

    PubMed

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

    2014-07-01

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

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. Associations of Uric Acid with Polymorphisms in the δ-Aminolevulinic Acid Dehydratase, Vitamin D Receptor, and Nitric Oxide Synthase Genes in Korean Lead Workers

    PubMed Central

    Weaver, Virginia M.; Schwartz, Brian S.; Jaar, Bernard G.; Ahn, Kyu-Dong; Todd, Andrew C.; Lee, Sung-Soo; Kelsey, Karl T.; Silbergeld, Ellen K.; Lustberg, Mark E.; Parsons, Patrick J.; Wen, Jiayu; Lee, Byung-Kook

    2005-01-01

    Recent research suggests that uric acid may be nephrotoxic at lower levels than previously recognized and that it may be one mechanism for lead-related nephrotoxicity. Therefore, in understanding mechanisms for lead-related nephrotoxicity, it would be of value to determine whether genetic polymorphisms that are associated with renal outcomes in lead workers and/or modify associations between lead dose and renal function are also associated with uric acid and/or modify associations between lead dose and uric acid. We analyzed data on three such genetic polymorphisms: δ-aminolevulinic acid dehydratase (ALAD), endothelial nitric oxide synthase (eNOS), and the vitamin D receptor (VDR). Mean (± SD) tibia, blood, and dimercaptosuccinic acid–chelatable lead levels were 37.2 ± 40.4 μg/g bone mineral, 32.0± 15.0 g/dL, and 0.77± 0.86 μg/mg creatinine, respectively, in 798 current and former lead workers. Participants with the eNOS Asp allele had lower mean serum uric acid compared with those with the Glu/Glu genotype. Among older workers (age ≥ median of 40.6 years), ALAD genotype modified associations between lead dose and uric acid levels. Higher lead dose was significantly associated with higher uric acid in workers with the ALAD1-1 genotype; associations were in the opposite direction in participants with the variant ALAD1-2 genotype. In contrast, higher tibia lead was associated with higher uric acid in those with the variant VDR B allele; however, modification was dependent on participants with the bb genotype and high tibia lead levels. We conclude that genetic polymorphisms may modify uric acid mediation of lead-related adverse renal effects. PMID:16263504

  2. 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.

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

    PubMed Central

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

    2014-01-01

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

  4. 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.

  5. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Uric acid test system. 862.1775 Section 862.1775...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1775 Uric acid test system. (a) Identification. A uric acid test system is a device intended to...

  6. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Uric acid test system. 862.1775 Section 862.1775...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1775 Uric acid test system. (a) Identification. A uric acid test system is a device intended to...

  7. THE REGULATION OF UREA-BIOSYNTHESIS ENZYMES IN VERTEBRATES.

    PubMed

    MORA, J; MARTUSCELLI, J; ORTIZ PINEDA, J; SOBERON, G

    1965-07-01

    1. Carbamoyl phosphate synthetase, ornithine transcarbamoylase, the arginine-synthetase system and arginase were measured in the livers of ammoniotelic, ureotelic and uricotelic animals. The chelonian reptiles, whose nitrogen excretory patterns vary according to the habitat, and the Mexican axolotl, a neotenic species, were also studied. 2. The levels of the activities of the first three enzymes mentioned correlate with the amount of nitrogen excreted as urea. 3. The terrestrial turtle, which excretes mainly uric acid, maintains a high arginase activity but has very low levels of the activities of the other three enzymes. 4. The first three enzymes of the urea cycle vary in the phylogenic scale in a co-ordinated manner, which suggests that they are under the same regulatory mechanism. 5. Urea formation from endogenous arginine in vitro has a low efficiency in the Mexican axolotl. 6. The induction of metamorphosis in the Mexican axolotl by the administration of l-tri-iodothyronine, which causes a shift from ammonio-ureotelism to complete ureotelism, is accompanied by an increase mainly in carbamoyl phosphate synthetase and also by an improvement in the efficiency of hydrolysis of endogenous arginine in vitro to give urea. 7. The results obtained by differential centrifugation of the urea-cycle enzymes in rat and Mexican-axolotl livers are presented. The location requirements for the integration of a metabolic cycle are discussed. PMID:14343146

  8. [Uric acid, kidney disease and nephrolithiasis].

    PubMed

    Kim, Min Jeong; Hopfer, Helmut; Mayr, Michael

    2016-01-01

    Different types of kidney disease are known to be associated with hyperuricemia. The underlying pathophysiologic mechanisms strongly vary, and different ways of therapeutic approach are therefore required. In tumor lysis syndrome, a rapid, excessive increase of serum uric acid level can cause an acute renal failure. For chronic urate nephropathy, on the other hand, constantly elevated serum uric acid level for a longer period seems to be important. Being still controversial as a disease entity however, the aetiology for putative chronic urate nephropathy might be in fact chronic lead intoxication, as suggested by quite an amount of association data. In terms of uric acid nephrolithiasis, the major risk factor is a urinary acidification defect with persistently acidic urine pH, and not necessarily hyperuricemia or hyperuricosuria. Evidence suggests that metabolic diseases with increased insulin resistance are strongly associated with urinary acidification defect. Patients with uric acid kidney stones should therefore be thoroughly evaluated for such metabolic diseases and in a positive case adequately treated.

  9. [Uric acid, kidney disease and nephrolithiasis].

    PubMed

    Kim, Min Jeong; Hopfer, Helmut; Mayr, Michael

    2016-01-01

    Different types of kidney disease are known to be associated with hyperuricemia. The underlying pathophysiologic mechanisms strongly vary, and different ways of therapeutic approach are therefore required. In tumor lysis syndrome, a rapid, excessive increase of serum uric acid level can cause an acute renal failure. For chronic urate nephropathy, on the other hand, constantly elevated serum uric acid level for a longer period seems to be important. Being still controversial as a disease entity however, the aetiology for putative chronic urate nephropathy might be in fact chronic lead intoxication, as suggested by quite an amount of association data. In terms of uric acid nephrolithiasis, the major risk factor is a urinary acidification defect with persistently acidic urine pH, and not necessarily hyperuricemia or hyperuricosuria. Evidence suggests that metabolic diseases with increased insulin resistance are strongly associated with urinary acidification defect. Patients with uric acid kidney stones should therefore be thoroughly evaluated for such metabolic diseases and in a positive case adequately treated. PMID:27008449

  10. Lower uric Acid linked with cognitive dysfunction in the elderly.

    PubMed

    Méndez-Hernández, Edna; Salas-Pacheco, José; Ruano-Calderón, Luis; Téllez-Valencia, Alfredo; Cisneros-Martínez, Jorge; Barraza-Salas, Marcelo; Arias-Carrión, Oscar

    2015-01-01

    Uric acid has been associated as a risk factor for cardiovascular disease. Recently, however, there is growing evidence that uric acid plays a role as antioxidant in the brain. In cognitive dysfunction, vascular and oxidative stress mechanisms play a role, but the link remains unknown. Therefore, we investigated the link between serum uric acid-levels and cognitive function in 62 elderly subjects. The statistical analysis was adjusted to age, sex and cardiovascular risk factors. Here, we found that lower serum uric acid levels are linked to cognitive dysfunction. In a Mexican population, higher levels of uric acid are associated with a decreased risk of dementia. PMID:25925000

  11. A review on creatinine measurement techniques.

    PubMed

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

    2012-08-15

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

  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 μmol 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 μmol L-1 respectively whereas Sandell's sensitivity and molar absorption coefficient values were 0.0407 μg 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. Urine Protein and Urine Protein to Creatinine Ratio

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? Urine Protein and Urine Protein to Creatinine Ratio Share this page: Was this page helpful? Also known as: 24-Hour Urine Protein; Urine Total Protein; Urine Protein to Creatinine Ratio; ...

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

    PubMed

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

    2014-09-01

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

  15. The urea cycle disorders.

    PubMed

    Helman, Guy; Pacheco-Colón, Ileana; Gropman, Andrea L

    2014-07-01

    The urea cycle is the primary nitrogen-disposal pathway in humans. It requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate, and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. Accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurologic sequelae. The disorders may present at any age from the neonatal period to adulthood, with the more severely affected patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. Here the authors address neurologic presentations of ornithine transcarbamylase deficiency in detail, the most common of the urea cycle disorders, neuropathology, neurophysiology, and our studies in neuroimaging. Special attention to late-onset presentations is given.

  16. The Effects of Lead Exposure on Serum Uric Acid and Hyperuricemia in Chinese Adults: A Cross-Sectional Study.

    PubMed

    Dai, Haijiang; Huang, Zhijun; Deng, Qihong; Li, Ying; Xiao, Ting; Ning, Xingping; Lu, Yao; Yuan, Hong

    2015-08-18

    The aim of this study was to assess the correlation between blood lead levels and both serum uric acid and hyperuricemia in adult residents living within an area of China with lead pollution. We conducted a cross-sectional analysis of 2120 subjects (1180 of whom were male) between the ages of 20 and 75 years who had undergone health examinations at the Centers for Disease Control and Prevention (CDC) in a lead-polluted area of China between January 2013 and August 2014. Blood lead was positively correlated with serum uric acid in both males (r = 0.095, p = 0.001) and females (r = 0.134, p < 0.001). Multivariate linear regression analysis demonstrated that for males, blood lead (p = 0.006), age (p = 0.001), current smoking (p = 0.012), education (p = 0.001), triglycerides (TG) (p < 0.001), and serum creatinine (p < 0.001) were independently associated with serum uric acid. For females, blood lead (p < 0.001), body mass index (BMI) (p = 0.009), and TG (p < 0.001) were independently associated with serum uric acid. After multiple adjustments, blood lead was significantly associated with a higher prevalence of hyperuricemia when female subjects were categorized into quartiles (for the highest quartile vs. the lowest quartile, odds ratio (OR) = 2.190; 95% confidence interval (CI): 1.106-4.338; p = 0.025); however, no such association was observed for male subjects. Continuous lead exposure has an independent impact on serum uric acid for both males and females, although this impact is more pronounced for females than for males. Lead exposure is significantly associated with hyperuricemia for females but not for males.

  17. [Outpatient care in uric acid disorders].

    PubMed

    Schwenke, R; Altus, R E; Kirschner, I

    1979-08-15

    In 35 patients with uricopathy (arthritis urica, essential hyperuricaemia) the serum uric acid values, consumption of alcohol, overweight, hypertension and liver enzyma under dietary and medicamentous therapy (allopurinol) were investigated. Here during an observation lasting 12--48 months allopurinol proved as a well tolerable uricostatic drug which was sufficiently effective also with a considerable exogenic purine application. We only insufficiently succeeded in influencing overweight and alcohol consumption as well as hypertension by rheumatic dispensary care and family doctor.

  18. Amylase creatinine clearance ratio after biliary surgery.

    PubMed

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

    1977-01-01

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

  19. Amylase creatinine clearance ratio after biliary surgery.

    PubMed

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

    1977-01-01

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

  20. Detection of Interstellar Urea

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  1. [Uric acid and kidneys – Physiological and pathophysiological aspects].

    PubMed

    Kim, Min Jeong; Mayr, Michael

    2016-01-01

    Kidneys play a critical role in the excretion of uric acid. Improved knowledge of the renal tubular uric acid transport mechanisms helps to better understand, why hyper- or hypouricemia can develop without the external influence of purine intake. Besides the genetic mutations, several drugs and specific medical conditions can significantly influence the tubular excretion of uric acid and thus the serum uric acid level. It seems evident that the renal function per se has a relevant impact on the uric acid excretion. It is however not clear, whether uric acid has a causal role in the development of chronic kidney disease and if so, to what extent. In order to better understand the impact of hyper- and hypouricemia and especially their clinical relevance, further researches on the renal tubular physio- and pathophysiology and also high quality intervention studies are required.

  2. Uric acid excretion predicts increased aggression in urban adolescents.

    PubMed

    Mrug, Sylvie; Mrug, Michal

    2016-09-01

    Elevated levels of uric acid have been linked with impulsive and disinhibited behavior in clinical and community populations of adults, but no studies have examined uric acid in relation to adolescent aggression. This study examined the prospective role of uric acid in aggressive behavior among urban, low income adolescents, and whether this relationship varies by gender. A total of 84 adolescents (M age 13.36years; 50% male; 95% African American) self-reported on their physical aggression at baseline and 1.5years later. At baseline, the youth also completed a 12-h (overnight) urine collection at home which was used to measure uric acid excretion. After adjusting for baseline aggression and age, greater uric acid excretion predicted more frequent aggressive behavior at follow up, with no significant gender differences. The results suggest that lowering uric acid levels may help reduce youth aggression. PMID:27180134

  3. [Uric acid and kidneys – Physiological and pathophysiological aspects].

    PubMed

    Kim, Min Jeong; Mayr, Michael

    2016-01-01

    Kidneys play a critical role in the excretion of uric acid. Improved knowledge of the renal tubular uric acid transport mechanisms helps to better understand, why hyper- or hypouricemia can develop without the external influence of purine intake. Besides the genetic mutations, several drugs and specific medical conditions can significantly influence the tubular excretion of uric acid and thus the serum uric acid level. It seems evident that the renal function per se has a relevant impact on the uric acid excretion. It is however not clear, whether uric acid has a causal role in the development of chronic kidney disease and if so, to what extent. In order to better understand the impact of hyper- and hypouricemia and especially their clinical relevance, further researches on the renal tubular physio- and pathophysiology and also high quality intervention studies are required. PMID:27008450

  4. Chemiresistor urea sensor

    DOEpatents

    Glass, Robert S.

    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.

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

    PubMed Central

    2011-01-01

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

  6. Urea may regulate urea transporter protein abundance during osmotic diuresis.

    PubMed

    Kim, Dongun; Klein, Janet D; Racine, Sandy; Murrell, Brian P; Sands, Jeff M

    2005-01-01

    Rats with diabetes mellitus have an increase in UT-A1 urea transporter protein abundance and absolute urea excretion, but the relative amount (percentage) of urea in total urinary solute is actually decreased due to the marked glucosuria. Urea-specific signaling pathways have been identified in mIMCD3 cells and renal medulla, suggesting the possibility that changes in the percentage or concentration of urea could be a factor that regulates UT-A1 abundance. In this study, we tested the hypothesis that an increase in a urinary solute other than urea would increase UT-A1 abundance, similar to diabetes mellitus, whereas an increase in urine urea would not. In both inner medullary base and tip, UT-A1 protein abundance increased during NaCl- or glucose-induced osmotic diuresis but not during urea-induced osmotic diuresis. Next, rats undergoing NaCl or glucose diuresis were given supplemental urea to increase the percentage of urine urea to control values. UT-A1 abundance did not increase in these urea-supplemented rats compared with control rats. Additionally, both UT-A2 and UT-B protein abundances in the outer medulla increased during urea-induced osmotic diuresis but not in NaCl or glucose diuresis. We conclude that during osmotic diuresis, UT-A1 abundance increases when the percentage of urea in total urinary solute is low and UT-A2 and UT-B abundances increase when the urea concentration in the medullary interstitium is high. These findings suggest that a reduction in urine or interstitial urea results in an increase in UT-A1 protein abundance in an attempt to restore inner medullary interstitial urea and preserve urine-concentrating ability.

  7. 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.

  8. Creatinine metabolism in Cryptococcus neoformans and Cryptococcus bacillisporus.

    PubMed Central

    Polacheck, I; Kwon-Chung, K J

    1980-01-01

    The pathogenic species of Cryptococcus, C. neoformans and C. bacillisporus, utilized creatinine as a source of nitrogen but not of carbon. Chromatographic and autoradiographic studies suggest that creatinine metabolism in both species involves a single step resulting in the production of methylhydantoin and ammonia. The enzyme responsible for this step, creatinine deiminase, was produced by the cells only in the presence of creatinine in both species. The synthesis of creatinine deiminase was repressed by ammonia in C. neoformans, but not in C. bacillisporus. A possible explanation for this variation, based on the ecological differences between the two species, is discussed. A novel method for measuring creatinine deiminase activity is also described. Images PMID:6989801

  9. Modulation of water transport in human red cells: effect of urea.

    PubMed

    Toon, M R; Solomon, A K

    1988-05-24

    We have studied the effect of urea on water flux in the human red cell and have found that 500 mosmolal urea inhibits osmotic water transport by 39%. The Ki for urea inhibition of water flux is 550 +/- 80 mosmolal, higher than, but comparable with, the Km of urea transport into the red cell of 220-330 mM given by Mayrand and Levitt (J. Gen. Physiol. 55 (1983) 427) and Brahm (J. Gen. Physiol. 82 (1983) 1). Other amides, such as propionamide and valeramide, as well as methyl-substituted ureas, have similar effects, although an indifferent molecule, such as 0.5 M creatinine, has no effect. Urea can be washed off the inhibition site with buffer, and the effects of urea concentrations as high as 1.2 osmolal are entirely reversible. 500 mosmolal urea also significantly increases the reflection coefficient for ethylene glycol, sigma eth gly, from 0.71 +/- 0.03 in control experiments to 0.86 +/- 0.04 (P less than 0.0005, t-test), and propionamide has a similar effect on sigma eth gly. These results show that urea can modulate ethylene glycol transport through the red cell membrane, and are consistent with, but not proof of, the presence of a single class of aqueous channels through which both ethylene glycol and urea enter the red cell. It is suggested that the physiological purpose of these low-affinity urea sites is to modulate water flow out of the red cell during passage through the regions of 0.5-0.6 M urea in the kidney. PMID:3370207

  10. Serum Uric Acid Level among Acute Stroke Patients.

    PubMed

    Mohsin, M; Das, S N; Haque, M F; Shikha, S S; Bhuiyan, A S; Saha, P L; Das, B R; Chowdhury, M; Jahan, M K; Rahman, M M

    2016-04-01

    Stroke is one of the leading causes of death and disability in developed as well as developing countries like Bangladesh. Elevated serum uric acid levels may predict an increased risk for cerebro-vascular (CV) events including stroke. Aim of the study was to measure the serum uric acid level among stroke patients and determine the relationship between serum uric acid level and stroke. This descriptive, cross-sectional study was carried out in Department of Medicine, Mymensingh Medical College Hospital, Mymensingh, Bangladesh to measure serum uric acid level among 102 stroke patients in a period of one year by using non-probability sampling procedure. Finally, collected data were analyzed using SPSS software Version 17.0. It was observed that the mean age of patients was 60.87±8.05 years, of them 80(78.43%) patients were male and the rest 22(21.57%) were female. About 66(64.70%) of respondents were in age group 60 years and above, while 36(35.30%) were in age group 59 years and below. At least 23(22.55%) of stroke patients had elevated serum uric acid with a mean serum uric acid level of 5.18mg/dl and standard deviation 1.26mg/dl. About 23(27.38%) patients in ischemic stroke had elevated serum uric acid whereas 18(100%) patients in hemorrhagic stroke had normal uric acid level. Uric acid level was elevated in ischemic stroke than haemorrhagic stroke patients (p<0.001). High uric acid level may be considered as a risk factor in patients with acute ischemic stroke. PMID:27277350

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

    PubMed Central

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

    1997-01-01

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

  12. Serum Creatinine and Functional Limitation in Elderly Persons

    PubMed Central

    Shlipak, Michael G.; Tager, Ira B.

    2009-01-01

    Background Creatinine is a commonly used measure of kidney function, but serum levels are also influenced by muscle mass. We hypothesized that higher serum creatinine would be associated with self-reported functional limitation in community-dwelling elderly. Methods Subjects (n = 1,553) were participants in the Study of Physical Performance and Age-Related Changes in Sonomans, a cohort to study aging and physical function. We explored three strategies to account for the effects of muscle mass on serum creatinine. Results We observed a J-shaped association of creatinine with functional limitation. Above the study-specific mean creatinine (0.97 mg/dL in women and 1.15 mg/dL in men), the unadjusted odds ratio of functional limitation per standard deviation (0.20 mg/dL in women and 0.23 mg/dL in men) higher creatinine was 2.27 (95% confidence interval [CI] 1.75–2.94, p < .001) in women and 1.42 (95% CI 1.12–1.80, p = .003) in men. This association was inverted in persons with creatinine levels below the mean. Adjustment for muscle mass did not have an important effect on the association between creatinine and functional limitation. These associations remained after multivariable adjustment for demographics and health conditions but were statistically significant only in women. Conclusions In elderly adults, higher creatinine levels are associated with functional limitation, consistent with prior literature that has demonstrated reduced physical performance in persons with kidney disease. However, the association of low creatinine levels with functional limitation suggests that creatinine levels are influenced by factors other than kidney function and muscle mass in the elderly. PMID:19181716

  13. Urea distribution in renal failure

    PubMed Central

    Blackmore, D. J.; Elder, W. J.; Bowden, C. H.

    1963-01-01

    An assessment of intracellular urea removed during haemodialysis has been made from urea extraction and plasma urea estimations. An apparent wide variation in the movement of intracellular urea in patients with acute renal failure from obstetric and traumatic causes and with chronic renal failure is reported. A method for the estimation of red cell water urea is presented. In two patients with chronic renal failure the red cell urea level was much higher than would have been expected from the plasma urea level before dialysis. In two obstetric patients there was no such discrepancy. The conclusion is drawn that research should be directed to variations of intracellular metabolism in renal failure before a more rational approach can be made to its management. PMID:16811009

  14. Towards optoelectronic urea biosensors.

    PubMed

    Pokrzywnicka, Marta; Koncki, Robert; Tymecki, Łukasz

    2015-03-01

    Integration of immobilized enzymes with light-emitting diodes (LEDs) leads to the development of optoelectronic enzyme-based biosensors. In this work, urease, used as a model enzyme, immobilized in the form of an open-tubular microbioreactor or biosensing membrane that has been integrated with two red LEDs. It forms complete, fiberless, miniaturized, and extremely economic biooptoelectronic devices useful for nonstationary measurements under flow analysis conditions. Both enzyme-based biodevices, operating according to the paired emitter detector diode (PEDD) principle, allow relatively fast, highly sensitive, and well-reproducible urea detection in the millimolar range of concentrations. Potential analytical applications of the developed urea bioPEDDs have been announced. Both presented constructions will be easily adapted for the development of other optoelectronic biosensors exploring various enzyme-based schemes of biodetection. PMID:25619983

  15. 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.

  16. Creatinine Deiminase Adsorption onto Silicalite-Modified pH-FET for Creation of New Creatinine-Sensitive Biosensor.

    PubMed

    Marchenko, Svitlana V; Soldatkin, Oleksandr O; Kasap, Berna Ozansoy; Kurc, Burcu Akata; Soldatkin, Alexei P; Dzyadevych, Sergei V

    2016-12-01

    In the work, silicalite particles were used for the surface modification of pH-sensitive field-effect transistors (pH-FETs) with the purpose of developing new creatinine-sensitive biosensor. Creatinine deiminase (CD) adsorbed on the surface of silicalite-coated pH-FET served as a bioselective membrane. The biosensor based on CD immobilized in glutaraldehyde vapor (GA) was taken as control. The creatinine-sensitive biosensor obtained by adsorption on silicalite was shown to have better analytical characteristics (two- to threefold increased sensitivity to creatinine, three- to fourfold lesser response and recovery times, a decrease of the detection limit of creatinine determination to 5 μM, etc.).Additionally, the biosensor based on CD adsorbed on silicalite (Sil/CD) was characterized by high signal reproducibility (relative standard deviation (RSD) for creatinine measurement = 2.6 %) and stability during storage (over 13 months). It was experimentally confirmed that the proposed biosensor was not sensitive either to high concentrations of sodium chloride or to the macromolecular protein fractions and can be used for direct quantitative analysis of creatinine in the blood serum.It was concluded that the method of CD adsorption on silicalite is well-suited for the creation of creatinine-sensitive biosensor with improved working characteristics. PMID:27033849

  17. Use of polyurea from urea for coating of urea granules.

    PubMed

    Lu, Panfang; Zhang, Yanfei; Jia, Cong; Li, Yufeng; Mao, Zhiquan

    2016-01-01

    A new type of controlled release fertilizers coated with polyurea was prepared. The granulated urea was firstly changed into a liquid urea by heating as the coating liquid. By spraying uniformly the urea was coated with the polyurea synthesized by the reaction of isocyanates with a liquid urea. The effects of different modifiers on N release characteristics of polyurea-coated urea (PCU) were studied. The morphology and chemical structure of PCU coating materials was investigated by SEM and FTIR. We studied the nitrogen release characteristics of the PCU applied in both water and soil, and the biodegradability of PCU coating after buried in soil. The results showed that PCU reduced nitrogen release rate and exhibited excellent controlled release property. The PCU coating materials could biodegrade in soil. This indicated that the low cost PCU products from urea are expected to use in agricultural and horticultural applications. PMID:27119061

  18. Use of polyurea from urea for coating of urea granules.

    PubMed

    Lu, Panfang; Zhang, Yanfei; Jia, Cong; Li, Yufeng; Mao, Zhiquan

    2016-01-01

    A new type of controlled release fertilizers coated with polyurea was prepared. The granulated urea was firstly changed into a liquid urea by heating as the coating liquid. By spraying uniformly the urea was coated with the polyurea synthesized by the reaction of isocyanates with a liquid urea. The effects of different modifiers on N release characteristics of polyurea-coated urea (PCU) were studied. The morphology and chemical structure of PCU coating materials was investigated by SEM and FTIR. We studied the nitrogen release characteristics of the PCU applied in both water and soil, and the biodegradability of PCU coating after buried in soil. The results showed that PCU reduced nitrogen release rate and exhibited excellent controlled release property. The PCU coating materials could biodegrade in soil. This indicated that the low cost PCU products from urea are expected to use in agricultural and horticultural applications.

  19. Creatinine Deiminase Adsorption onto Silicalite-Modified pH-FET for Creation of New Creatinine-Sensitive Biosensor

    NASA Astrophysics Data System (ADS)

    Marchenko, Svitlana V.; Soldatkin, Oleksandr O.; Kasap, Berna Ozansoy; Kurc, Burcu Akata; Soldatkin, Alexei P.; Dzyadevych, Sergei V.

    2016-03-01

    In the work, silicalite particles were used for the surface modification of pH-sensitive field-effect transistors (pH-FETs) with the purpose of developing new creatinine-sensitive biosensor. Creatinine deiminase (CD) adsorbed on the surface of silicalite-coated pH-FET served as a bioselective membrane. The biosensor based on CD immobilized in glutaraldehyde vapor (GA) was taken as control. The creatinine-sensitive biosensor obtained by adsorption on silicalite was shown to have better analytical characteristics (two- to threefold increased sensitivity to creatinine, three- to fourfold lesser response and recovery times, a decrease of the detection limit of creatinine determination to 5 μM, etc.).

  20. Scale control in urea solutions

    SciTech Connect

    Dubin, L.; Diep, D.V.

    1997-08-01

    Legislation to control NO{sub x} emissions, one cause of acid rain and ozone induced smog, has created an impetus to control NO{sub x} emissions. Selective Non Catalytic Reduction (SNCR) using urea chemistry is utilized to control NO{sub x} emissions from boilers, municipal waste incinerators, refinery furnaces, recovery boilers, utilities and other stationary combustion sources. Control requires injecting urea-based solutions into the flue gas at specified temperatures. Urea solutions accelerate CaCO{sub 3} precipitation in industrial waters used for dilution, and thereby interfere with proper application of the urea solution. The negative effect of urea solutions on hardness stability is discussed as well as how CaCO{sub 3} precipitation in urea solution can be controlled by suitable scale inhibitors.

  1. An Increase Incidence in Uric Acid Nephrolithiasis: Changing Patterns

    PubMed Central

    Kumari, Asha; Mittal, Pawan; Kumar, Rajender; Goel, Richa; Bansal, Piyush; Kumar, Himanshu Devender; Bhutani, Jaikrit

    2016-01-01

    Introduction Nephrolithiasis is a complex disease affecting all age groups globally. As the causative factors for nephrolithiasis rises significantly, its incidence, prevalence and recurrence continues to baffle clinicians and patients. Aim To study the prevalence of different types of renal stones extracted by Percutaneous Nephrolithotomy (PCNL) and open surgical procedures. Materials and Methods Renal stones from 50 patients were retrieved by Percutaneous Nephrolithotomy (PCNL), Ureterorenoscopy (URS) and open surgical techniques for qualitative tests for detection of calcium, oxalate, uric acid, phosphate, ammonium ion, carbonate, cystine and xanthine. Results Three patients had stone removed by open surgery and rest had undergone PCNL. Nine of the stones were pure of calcium oxalate, 9 were of pure uric acid and 32 were mixed stones. Forty one stones had calcium. Among the mixed stones, oxalate was present in 25 samples (39 of total), uric acid was seen in 17 (25 of total stones), phosphate was present in 23 (23 of total) and carbonate was present in 4 stones (4 of total). Only 1 patient had triple phosphate stone. 12 were of staghorn appearance of which 6 were of struvite type, 6 were pure uric acid and remaining were mixed oxalate-phosphate stones. Conclusion Our study, though in a small number of hospital based patients, found much higher prevalence of uric acid stones and mixed stones than reported by previous hospital based studies in north India (oxalate stones~90%, uric acid~1% and mixed stones~3%). Biochemical analysis of renal stones is warranted in all cases. PMID:27630833

  2. An Increase Incidence in Uric Acid Nephrolithiasis: Changing Patterns

    PubMed Central

    Kumari, Asha; Mittal, Pawan; Kumar, Rajender; Goel, Richa; Bansal, Piyush; Kumar, Himanshu Devender; Bhutani, Jaikrit

    2016-01-01

    Introduction Nephrolithiasis is a complex disease affecting all age groups globally. As the causative factors for nephrolithiasis rises significantly, its incidence, prevalence and recurrence continues to baffle clinicians and patients. Aim To study the prevalence of different types of renal stones extracted by Percutaneous Nephrolithotomy (PCNL) and open surgical procedures. Materials and Methods Renal stones from 50 patients were retrieved by Percutaneous Nephrolithotomy (PCNL), Ureterorenoscopy (URS) and open surgical techniques for qualitative tests for detection of calcium, oxalate, uric acid, phosphate, ammonium ion, carbonate, cystine and xanthine. Results Three patients had stone removed by open surgery and rest had undergone PCNL. Nine of the stones were pure of calcium oxalate, 9 were of pure uric acid and 32 were mixed stones. Forty one stones had calcium. Among the mixed stones, oxalate was present in 25 samples (39 of total), uric acid was seen in 17 (25 of total stones), phosphate was present in 23 (23 of total) and carbonate was present in 4 stones (4 of total). Only 1 patient had triple phosphate stone. 12 were of staghorn appearance of which 6 were of struvite type, 6 were pure uric acid and remaining were mixed oxalate-phosphate stones. Conclusion Our study, though in a small number of hospital based patients, found much higher prevalence of uric acid stones and mixed stones than reported by previous hospital based studies in north India (oxalate stones~90%, uric acid~1% and mixed stones~3%). Biochemical analysis of renal stones is warranted in all cases.

  3. Urine Creatinine Excretion and Clinical Outcomes in CKD

    PubMed Central

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

    2013-01-01

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

  4. 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

  5. Enhancement of renal excretion of uric acid during long-term thiazide therapy.

    PubMed

    Pak, C Y; Tolentino, R; Stewart, A; Galosy, R A

    1978-11-01

    The effect of thiazide (hydrochlorothiazide 100 mg per day orally in two divided doses for up to 3 years) on uric acid metabolism was examined in 21 patients with renal stones suffering from renal hypercalciuria or absorptive hypercalciuria. Serum concentration of uric acid increased during thiazide therapy in every patient. In 12 of 21 patients, there was a transient or persistent rise in urinary uric acid of more than 50 mg per day during treatment. The mean urinary uric acid produced by thiazide was positively correlated with the change in the renal clearance of uric acid. Thus, an increase in urinary uric acid was often associated with a rise in uric acid clearance. The results suggest that thiazide may either increase the production of uric acid or decrease the extrarenal disposal of uric acid, in some patients.

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

    PubMed

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

    2013-03-01

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

  7. Uric acid and chronic kidney disease: which is chasing which?

    PubMed Central

    Johnson, Richard J.; Nakagawa, Takahiko; Jalal, Diana; Sánchez-Lozada, Laura Gabriela; Kang, Duk-Hee; Ritz, Eberhard

    2013-01-01

    Serum uric acid is commonly elevated in subjects with chronic kidney disease (CKD), but was historically viewed as an issue of limited interest. Recently, uric acid has been resurrected as a potential contributory risk factor in the development and progression of CKD. Most studies documented that an elevated serum uric acid level independently predicts the development of CKD. Raising the uric acid level in rats can induce glomerular hypertension and renal disease as noted by the development of arteriolosclerosis, glomerular injury and tubulointerstitial fibrosis. Pilot studies suggest that lowering plasma uric acid concentrations may slow the progression of renal disease in subjects with CKD. While further clinical trials are necessary, uric acid is emerging as a potentially modifiable risk factor for CKD. Gout was considered a cause of CKD in the mid-nineteenth century [1], and, prior to the availability of therapies to lower the uric acid level, the development of end-stage renal disease was common in gouty patients. In their large series of gouty subjects Talbott and Terplan found that nearly 100% had variable degrees of CKD at autopsy (arteriolosclerosis, glomerulosclerosis and interstitial fibrosis) [2]. Additional studies showed that during life impaired renal function occurred in half of these subjects [3]. As many of these subjects had urate crystals in their tubules and interstitium, especially in the outer renal medulla, the disease became known as gouty nephropathy. The identity of this condition fell in question as the presence of these crystals may occur in subjects without renal disease; furthermore, the focal location of the crystals could not explain the diffuse renal scarring present. In addition, many subjects with gout also had coexistent conditions such as hypertension and vascular disease, leading some experts to suggest that the renal injury in gout was secondary to these latter conditions rather than to uric acid per se [4]. Indeed, gout was

  8. [Considerations when using creatinine as a measure of kidney function].

    PubMed

    Drion, I Iefke; Fokkert, M J Marion; Bilo, H J G Henk

    2013-01-01

    Reported serum creatinine concentrations can sometimes vary considerably, even when the renal function does less so or even not. This variation is partly due to true changes in actual serum concentration, and partly due to interferences in the measurement technique, thus not reflecting a true change in concentration. Increased or decreased endogenous creatinine production, ingested creatinine sources through meat eating or certain creatine formulations, and interference by either browning of chromogenic substances in Jaffe measurement techniques or promotors and inhibitors of enzymatic reaction methods do play a role. Reliable serum creatinine measurements are needed for renal function estimating equations. In screening circumstances and daily practice, chronic kidney disease staging is based on these estimated glomerular filtration rate values. Given the possible influences on reported serum creatinine concentrations, it is important for health care workers to remain critical when interpreting outcomes of renal function estimating equations and to not see every reported result based on an equation as a true reflection of renal function. PMID:24330793

  9. Immobilized enzyme electrode for creatinine determination in serum.

    PubMed

    Nguyen, V K; Wolff, C M; Seris, J L; Schwing, J P

    1991-03-15

    An immobilized enzyme electrode for continuous creatinine determination in blood serum is described. The enzymes creatinine amidohydrolase, creatine amidinohydrolase, and sarcosine oxidase are coimmobilized to the surface of the polypropylene membrane of a Clark-type electrode responsive to oxygen. The immobilized enzymes catalyze the decomposition of creatinine with the consumption of oxygen and thus permit the creatinine measurement. The whole assay takes less than 1 min. Effects of pH and temperature on electrode response are also described. The proposed technique offers a rapid, simple, and inexpensive means to determine creatinine in blood serum within the normal and abnormal ranges. The repeatability of the creatine determination in serum is 2.5% (relative standard deviation), and the detection limit is 3 x 10(-6) mol L-1. The results obtained by this method were compared to those obtained with the Technicon AutoAnalyzer SMAC system based on the Jaffé reaction; the correlation factor between the two methods was found to be r = 0.9997.

  10. 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

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

    PubMed

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

    2013-09-01

    Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl) intake separately, and their interaction, on MUN and UUN, on the relationship between UUN and MUN, on renal recycling of urea, and on urea transfer to the gastrointestinal tract. Twelve second-parity cows (body weight of 645±37 kg, 146±29 d in milk, and a milk production of 34.0±3.28 kg/d), of which 8 were previously fitted with a rumen cannula, were fitted with catheters in the urine bladder and jugular vein. The experiment had a split-plot arrangement with dietary crude protein (CP) content as the main plot factor [116 and 154 g of CP/kg of dry matter (DM)] and dietary NaCl content as the subplot factor (3.1 and 13.5 g of Na/kg of DM). Cows were fed at 95% of the average ad libitum feed intake of cows receiving the low protein diets. Average MUN and UUN were, respectively, 3.90 mg of N/dL and 45 g of N/d higher for the high protein diets compared with the low protein diets. Compared with the low NaCl diets, MUN was, on average, 1.74 mg of N/dL lower for the high NaCl diets, whereas UUN was unaffected. We found no interaction between dietary content of protein and NaCl on performance characteristics or on MUN, UUN, urine production, and renal clearance characteristics. The creatinine clearance rate was not affected by dietary content of protein and NaCl. Urea transfer to the gastrointestinal tract, expressed as a fraction of plasma urea entry rate, was negatively related to dietary protein, whereas it was not affected by dietary NaCl content. We found no interaction between dietary protein and NaCl content on plasma urea entry rate and gastrointestinal urea entry rate or their ratio. The relationship between MUN and UUN was significantly affected by the class variable

  12. Urea phosphate as granular or fluid fertilizers

    SciTech Connect

    Blouin, G.M.

    1984-01-01

    Studies are being conducted of the production and agronomic characteristics of the phosphoric acid-urea adduct, urea phosphate, and of the various granular and fluid fertilizers that can be produced from it. Flowsheets are given for the production of urea phosphate. Characteristics of unpurified and purified urea phosphate are also given. (DLC)

  13. 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

  14. Evaporation of urea at atmospheric pressure.

    PubMed

    Bernhard, Andreas M; Czekaj, Izabela; Elsener, Martin; Wokaun, Alexander; Kröcher, Oliver

    2011-03-31

    Aqueous urea solution is widely used as reducing agent in the selective catalytic reduction of NO(x) (SCR). Because reports of urea vapor at atmospheric pressure are rare, gaseous urea is usually neglected in computational models used for designing SCR systems. In this study, urea evaporation was investigated under flow reactor conditions, and a Fourier transform infrared (FTIR) spectrum of gaseous urea was recorded at atmospheric pressure for the first time. The spectrum was compared to literature data under vacuum conditions and with theoretical spectra of monomolecular and dimeric urea in the gas phase calculated with the density functional theory (DFT) method. Comparison of the spectra indicates that urea vapor is in the monomolecular form at atmospheric pressure. The measured vapor pressure of urea agrees with the thermodynamic data obtained under vacuum reported in the literature. Our results indicate that considering gaseous urea will improve the computational modeling of urea SCR systems.

  15. Single baseline serum creatinine measurements predict mortality in critically ill patients hospitalized for acute heart failure

    PubMed Central

    Schefold, Joerg C.; Hodoscek, Lea Majc; Blöchlinger, Stefan; Doehner, Wolfram; von Haehling, Stephan

    2015-01-01

    Abstract Background Acute heart failure (AHF) is a leading cause of death in critically ill patients and is often accompanied by significant renal dysfunction. Few data exist on the predictive value of measures of renal dysfunction in large cohorts of patients hospitalized for AHF. Methods Six hundred and eighteen patients hospitalized for AHF (300 male, aged 73.3 ± 10.3 years, 73% New York Heart Association Class 4, mean hospital length of stay 12.9 ± 7.7 days, 97% non‐ischaemic AHF) were included in a retrospective single‐centre data analysis. Echocardiographic data, serum creatinine/urea levels, estimated glomerular filtration rate (eGFR), and clinical/laboratory markers were recorded. Mean follow‐up time was 2.9 ± 2.1 years. All‐cause mortality was recorded, and univariate/multivariate analyses were performed. Results Normal renal function defined as eGFR > 90 mL/min/1.73 m2 was noted in only 3% of AHF patients at baseline. A significant correlation of left ventricular ejection fraction with serum creatinine levels and eGFR (all P < 0.002) was noted. All‐cause mortality rates were 12% (90 days) and 40% (at 2 years), respectively. In a multivariate model, increased age, higher New York Heart Association class at admission, higher total cholesterol levels, and lower eGFR independently predicted death. Patients with baseline eGFR < 30 mL/min/1.73 m2 had an exceptionally high risk of death (odds ratio 2.80, 95% confidence interval 1.52–5.15, P = 0.001). Conclusions In a large cohort of patients with mostly non‐ischaemic AHF, enhanced serum creatinine levels and reduced eGFR independently predict death. It appears that patients with eGFR < 30 mL/min/1.73 m2 have poorest survival rates. Our data add to mounting data indicating that impaired renal function is an important risk factor for non‐survival in patients hospitalized for AHF.

  16. 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,...

  17. 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 §...

  18. 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 §...

  19. 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 §...

  20. 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 §...

  1. 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 §...

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

    PubMed

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

    2004-03-10

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

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

    ERIC Educational Resources Information Center

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

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

  4. Anion-induced urea deprotonation.

    PubMed

    Boiocchi, Massimo; Del Boca, Laura; Esteban-Gómez, David; Fabbrizzi, Luigi; Licchelli, Maurizio; Monzani, Enrico

    2005-05-01

    The urea-based receptor 1 (1-(7-nitrobenzo[1,2,5]oxadiazol-4-yl)-3-(4-nitrophenyl)urea, L--H), interacts with X- ions in MeCN, according to two consecutive steps: 1) formation of a hydrogen-bond complex [L--H...X]-; 2) deprotonation of L--H to give L- and [HX2]-, as shown by spectrophotometric and 1H NMR titration experiments. Step 2) takes place with more basic anions (fluoride, carboxylates, dihydrogenphosphate), while less basic anions (Cl-, NO2-, NO3-) do not induce proton transfer. On crystallisation from a solution containing L--H and excess Bu4NF, the tetrabutylammonium salt of the deprotonated urea derivative (Bu4N[L]) was isolated and its crystal and molecular structure determined. PMID:15770711

  5. Enhancement of the amylase-creatinine clearance ratio in pregnancy.

    PubMed

    Naeije, R; Neuray, F; Van Melsen, A; Delcourt, A

    1979-01-01

    The renal clearance of amylase, expressed as a proportion of simultaneous creatinine clearance (Cam/-Ccr), was determined in 131 women in various stages of pregnancy. No abnormal serum levels of amylase were found. A moderate but significant increase in Cam/Ccr occurred during the last 15 weeks of pregnancy. Possible causes for this change were investigated in smaller groups of subjects. No increase in rapidly cleared isoamylase could be detected. No modification in renal tubular handling of protein could be evidenced, as assessed by measurements of the renal clearance of beta 2 microglobulin, expressed as a proportion of simultaneous creatinine clearance. An incrased glomerular permeability to amylase probably accounts for elevated Cam/Ccr in pregnancy.

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

    PubMed

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

    1978-09-01

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

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

    PubMed

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

    1978-09-01

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

  8. What Is a Urea Cycle Disorder?

    MedlinePlus

    ... urine and removed from the body. In urea cycle disorders, the nitrogen accumulates in the form of ammonia, a highly toxic substance, resulting in hyperammonemia (elevated blood ... and severity of urea cycle disorders is highly variable. This depends on the ...

  9. Serum uric acid levels predict the development of albuminuria over 6 years in patients with type 1 diabetes: Findings from the Coronary Artery Calcification in Type 1 Diabetes study

    PubMed Central

    Jalal, Diana I.; Rivard, Christopher J.; Johnson, Richard J.; Maahs, David M.; McFann, Kimberly; Rewers, Marian; Snell-Bergeon, Janet K.

    2010-01-01

    Background. Recent studies suggest that uric acid is a mediator of diabetic nephropathy. We hypothesized that elevated serum uric acid levels are a strong predictor of albuminuria in patients with type 1 diabetes. Methods. We analyzed data from the Coronary Artery Calcification in Type 1 Diabetes study, a prospective observational study. A stepwise logistic regression model was applied to predict the development of micro- or macroalbuminuria after 6 years of follow-up in 324 participants who had no evidence of micro- or macroalbuminuria at baseline. A P-value <0.1 was used as the criteria for entry into and removal from the model. Results. The following factors were selected in the stepwise multivariate model as predictors of micro- or macroalbuminuria at the 6-year follow-up visit: baseline serum uric acid levels, HbA1c and pre-albuminuria. For every 1-mg/dl increase in serum uric acid levels at baseline, there was an 80% increased risk of developing micro- or macroalbuminuria at 6 years (odds ratio 1.8; 95% confidence interval 1.2, 2.8; P = 0.005). Additional covariates considered in the stepwise model were sex, age, duration of diabetes, angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker treatment, waist circumference, waist/hip ratio, body mass index, systolic and diastolic blood pressure, smoking, serum creatinine, cystatin C, high-density lipoprotein cholesterol and triglycerides. Conclusion. Elevated serum uric acid levels are a strong predictor of the development of albuminuria in patients with type 1 diabetes. PMID:20064950

  10. 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)

  11. 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 μm) 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

  12. Elevated levels of serum creatinine: recommendations for management and referral

    PubMed Central

    Mendelssohn, D C; Barrett, B J; Brownscombe, L M; Ethier, J; Greenberg, D E; Kanani, S D; Levin, A; Toffelmire, E B

    1999-01-01

    BACKGROUND: The potential benefits of earlier referral to a nephrologist of patients with elevated levels of serum creatinine include identifying and treating reversible causes of renal failure, slowing the rate of decline associated with progressive renal insufficiency, managing the coexisting conditions associated with chronic renal failure and facilitating efficient entry into dialysis programs for all patients who might benefit. METHODS: A subcommittee of the Canadian Society of Nephrology, which included representatives from family practice and internal medicine, conducted a MEDLINE search for the period 1966 to 1998 using the key words referral and consultation, dialysis, hemodialysis, peritoneal dialysis, renal replacement therapy and kidney diseases. Where published evidence was lacking, conclusions were reached by consensus. GUIDELINES: Earlier referral to nephrologists of patients with elevated creatinine levels is expected to lead to better health care outcomes and lower costs for both the patients and the health care system. All patients with newly discovered renal insufficiency (as evidenced by serum creatinine elevated to a level above the upper limit of the normal range of that laboratory, adjusted for age and height in children) must undergo investigations to determine the potential reversibility of disease, to evaluate the prognosis and to optimize planning of care. All patients with an established, progressive increase in serum creatinine level should be followed with a nephrologist. Adequate preparation for dialysis or transplantation (or both) requires at least 12 months of relatively frequent contact with a renal care team. Nephrologists should provide consultation in a timely manner for any patient with an elevated serum creatinine level. In addition, they should provide advice about what aspects of the condition require particularly urgent or emergency assessment. SPONSORS: This clinical practice guideline has been endorsed by the Canadian

  13. 40 CFR 721.9892 - Alkylated urea.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkylated urea. 721.9892 Section 721... Alkylated urea. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an alkylated urea (PMN P-93-1649) is subject to reporting under...

  14. 40 CFR 721.9892 - Alkylated urea.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkylated urea. 721.9892 Section 721... Alkylated urea. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an alkylated urea (PMN P-93-1649) is subject to reporting under...

  15. 40 CFR 721.9892 - Alkylated urea.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkylated urea. 721.9892 Section 721... Alkylated urea. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an alkylated urea (PMN P-93-1649) is subject to reporting under...

  16. 40 CFR 721.9892 - Alkylated urea.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkylated urea. 721.9892 Section 721... Alkylated urea. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an alkylated urea (PMN P-93-1649) is subject to reporting under...

  17. Controlling serum uric acid using febuxostat in cancer patients at risk of tumor lysis syndrome.

    PubMed

    Takai, Mihoko; Yamauchi, Takahiro; Fujita, Kei; Lee, Shin; Ookura, Miyuki; Kishi, Shinji; Urasaki, Yoshimasa; Yoshida, Akira; Iwasaki, Hiromichi; Ueda, Takanori

    2014-10-01

    Tumor lysis syndrome (TLS) is a life-threatening oncological emergency, in which control of serum uric acid (S-UA) levels is important. S-UA-lowering efficacy of a new xanthine oxidase inhibitor, febuxostat, was retrospectively evaluated in seven patients with hematological malignancies who were at an intermediate risk of developing TLS. A 10-mg dose of febuxostat was initiated and chemotherapy was started within 24 h of administering the first dose of febuxostat. Febuxostat was continued until at least day 7 of chemotherapy treatment. The UA-lowering treatment was considered effective if febuxostat reduced S-UA levels to ≤7.5 mg/dl by day 5. The mean S-UA level at base line was 6.4±2.6 mg/dl and, on day 5, the mean S-UA level was 4.7±1.8 mg/dl. All the patients achieved S-UA levels ≤7.5 mg/dl. Serum creatinine levels decreased from 0.93±0.25 to 0.85±0.25 mg/dl. The estimated glomerular filtration rate values increased from 69.7±24.5 to 76.9±26.2 ml/min. No adverse reactions were noted during the study period and no patients experienced progressive TLS. Successful control of S-UA and improved renal function were obtained in response to febuxostat treatment in cancer patients at a risk of TLS.

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

    PubMed

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

    2013-10-01

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

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

    PubMed

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

    2013-10-01

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

  20. 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.

  1. Uric Acid as a Target of Therapy in CKD

    PubMed Central

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

    2012-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  3. Evaluation of Serum Creatinine Changes With Integrase Inhibitor Use in Human Immunodeficiency Virus-1 Infected Adults

    PubMed Central

    Lindeman, Tara A.; Duggan, Joan M.; Sahloff, Eric G.

    2016-01-01

    This retrospective chart review evaluated changes in serum creatinine and creatinine clearance (CrCl) after initiation of an integrase inhibitor (INSTI)-based regimen as initial treatment in human immunodeficiency virus-infected adults. Serum creatinine and CrCl changes were similar to those seen in clinical trials for INSTIs. No renal-related serious adverse events or discontinuations occurred. PMID:27092314

  4. Aquaporin-9 and urea transporter-A gene deletions affect urea transmembrane passage in murine hepatocytes.

    PubMed

    Jelen, Sabina; Gena, Patrizia; Lebeck, Janne; Rojek, Aleksandra; Praetorius, Jeppe; Frøkiaer, Jørgen; Fenton, Robert A; Nielsen, Søren; Calamita, Giuseppe; Rützler, Michael

    2012-12-01

    In mammals, the majority of nitrogen from protein degradation is disposed of as urea. Several studies have partly characterized expression of urea transporters (UTs) in hepatocytes, where urea is produced. Nevertheless, the contribution of these proteins to hepatocyte urea permeability (P(urea)) and their role in liver physiology remains unknown. The purpose of this study was to biophysically examine hepatocyte urea transport. We hypothesized that the water, glycerol, and urea channel aquaporin-9 (AQP9) is involved in hepatocyte urea release. Stopped-flow light-scattering measurements determined that the urea channel inhibitors phloretin and dimethylurea reduced urea permeability of hepatocyte basolateral membranes by 70 and 40%, respectively. In basolateral membranes isolated from AQP9(-/-) and UT-A1/3(-/-) single-knockout and AQP9(-/-):UT-A1/3(-/-) double-knockout mice, P(urea) was decreased by 30, 40, and 76%, respectively, compared with AQP9(+/-):UT-A1/3(+/-) mice. However, expression analysis by RT-PCR did not identify known UT-A transcripts in liver. High-protein diet followed by 24-h fasting affected the concentrations of urea and ammonium ions in AQP9(-/-) mouse liver and plasma without generating an apparent tissue-to-plasma urea gradient. We conclude that AQP9 and unidentified UT-A urea channels constitute primary but redundant urea facilitators in murine hepatocytes.

  5. Uric acid in metabolic syndrome: From an innocent bystander to a central player

    PubMed Central

    Kanbay, Mehmet; Jensen, Thomas; Solak, Yalcin; Le, Myphuong; Roncal-Jimenez, Carlos; Rivard, Chris; Lanaspa, Miguel A.; Nakagawa, Takahiko; Johnson, Richard J.

    2016-01-01

    Uric acid, once viewed as an inert metabolic end-product of purine metabolism, has been recently incriminated in a number of chronic disease states, including hypertension, metabolic syndrome, diabetes, non-alcoholic fatty liver disease, and chronic kidney disease. Several experimental and clinical studies support a role for uric acid as a contributory causal factor in these conditions. Here we discuss some of the major mechanisms linking uric acid to metabolic and cardiovascular diseases. At this time the key to understanding the importance of uric acid in these diseases will be the conduct of large clinical trials in which the effect of lowering uric acid on hard clinical outcomes is assessed. Elevated uric acid may turn out to be one of the more important remediable risk factors for metabolic and cardiovascular diseases. PMID:26703429

  6. Caecal decomposition of uric acid in captive and free ranging willow ptarmigan (Lagopus lagopus lagopus).

    PubMed

    Mortensen, A; Tindall, A R

    1981-02-01

    Urine entering the caeca of birds contains significant amounts of uric acid. The discovery of great numbers of bacteria utilizing uric acid in the caeca has encouraged the discussion about nitrogen recycling in birds. In this work caecal decomposition of uric acid in wild and captive willow ptarmigan has been investigated using radioactively labelled uric acid injected directly into one of the caeca. The appearance of radioactive CO2 in the expired air was taken as an indication of uric acid breakdown. The decomposition occurred at a rate corresponding to a half-life of 26 min (11-36 min). The results are in accordance with the previously reported observations of huge numbers of uric acid utilizing bacteria in the caeca of a variety of birds, and also with the nitrogen recycling theory. However, no conclusion concerning the nitrogen recycling can be drawn. PMID:7282388

  7. 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

  8. Prolonged winter undernutrition and the interpretation of urinary allantoin:creatinine ratios in white-tailed deer

    USGS Publications Warehouse

    DelGiudice, Glenn D.; Kerr, Ken D.; Mech, L. David; Seal, Ulysses 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 µmol:µmol). 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

  9. Clinical aspects of urea transporters.

    PubMed

    Ran, Jianhua; Wang, Hongkai; Hu, Tinghai

    2014-01-01

    Jk antigens, which were identified as urea transporter B (UT-B) in the plasma membrane of erythrocytes, and which determine the Kidd blood type in humans, are involved in transfusion medicine, and even in organ transplantation. The Jk(a-b-) blood type is a consequence of a silent Slc14A1 gene caused by various mutations related to lineage. In addition, the specific mutations related to hypertension and metabolic syndrome cannot be ignored. Genome-wide association studies established Slc14A1 as a related gene of bladder cancer and some genotypes are associated with higher morbidity. This chapter aims to introduce the clinical significance of urea transporters. PMID:25298346

  10. Urea biosensor for hemodialysis monitoring

    DOEpatents

    Glass, Robert S.

    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.

  11. 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.

  12. Uric Acid and Coronary Artery Disease, Two Sides of a Single Coin: A Determinant of Antioxidant System or a Factor in Metabolic Syndrome

    PubMed Central

    Bagheri, Babak; Zargari, Mehryar; Meshkini, Fatemeh; Dinarvand, Kolsoum; Mokhberi, Vahid; Azizi, Soheil

    2016-01-01

    Introduction Uric acid has antioxidant activity and it is expected to protect against coronary artery disease (CAD). Contradictory, it is a component of metabolic syndrome and so a risk factor for CAD. The associations of plasma total antioxidant capacity (TAOC) and uric acid (UA) as well as other risk factors were investigated relative to the occurrence and severity of CAD. Materials and Methods The study population consisted of 148 males and 152 females aged 35-76 years who were classified as CAD cases and controls according to the results of coronary angiography. The severity of CAD was scored on the basis of the number and the extent of lesions at coronary arteries. The concentrations of UA and TAOC were measured by using of FRAP and enzymatic uricase methods. Results The prevalence of hypertension, cigarette smoking and diabetes mellitus was more frequent in CAD cases than controls. Patients with CAD when compared with the controls had increased levels of glucose, triglycerides, creatinine, UA, TAOC and decreased levels of HDL- cholesterol. Serum UA was high positive correlate of serum total and LDL-cholesterol, triglyceride, creatinine, BUN, bilirubin, TAOC and negative correlate of glucose and HDL-C. TAOC and its major determinant UA but not bilirubin and albumin are significantly associated with the prevalence and severity of CAD. In multivariate analysis and in the absence of hypertension, UA but not TAOC would remain and be associated with CAD by the OR of 1.57 (1.07-2.29), p=0.02. If the results adjusted for all major risk factors including hypertension, neither TAOC nor UA would remain in the regression equation. Conclusion The results suggest that TAOC and UA but not bilirubin and albumin are associated with CAD significantly. But, the correlation is not independent and is attributed to the metabolic syndrome. The measurement of UA and TAOC will not improve the prognostic power beyond the classical risk factors. PMID:27042498

  13. Effects of varying ruminally undegradable protein supplementation on forage digestion, nitrogen metabolism, and urea kinetics in Nellore cattle fed low-quality tropical forage.

    PubMed

    Batista, E D; Detmann, E; Titgemeyer, E C; Valadares Filho, S C; Valadares, R F D; Prates, L L; Rennó, L N; Paulino, M F

    2016-01-01

    Effects of supplemental RDP and RUP on nutrient digestion, N metabolism, urea kinetics, and muscle protein degradation were evaluated in Nellore heifers () consuming low-quality signal grass hay (5% CP and 80% NDF, DM basis). Five ruminally and abomasally cannulated Nellore heifers (248 ± 9 kg) were used in a 5 × 5 Latin square. Treatments were the control (no supplement) and RDP supplementation to meet 100% of the RDP requirement plus RUP provision to supply 0, 50, 100, or 150% of the RUP requirement. Supplemental RDP (casein plus NPN) was ruminally dosed twice daily, and RUP supply (casein) was continuously infused abomasally. Jugular infusion of [NN]-urea with measurement of enrichment in urine was used to evaluate urea kinetics. The ratio of urinary 3-methylhistidine to creatinine was used to estimate skeletal muscle protein degradation. Forage NDF intake (2.48 kg/d) was not affected ( ≥ 0.37) by supplementation, but supplementation did increase ruminal NDF digestion ( < 0.01). Total N intake (by design) and N retention increased ( < 0.001) with supplementation and also linearly increased with RUP provision. Urea entry rate and gastrointestinal entry rate of urea were increased by supplementation ( < 0.001). Supplementation with RUP linearly increased ( = 0.02) urea entry rate and tended ( = 0.07) to linearly increase gastrointestinal entry rate of urea. Urea use for anabolic purposes tended ( = 0.07) to be increased by supplementation, and RUP provision also tended ( = 0.08) to linearly increase the amount of urea used for anabolism. The fraction of recycled urea N incorporated into microbial N was greater ( < 0.001) for control (22%) than for supplemented (9%) heifers. Urinary 3-methylhistidine:creatinine of control heifers was more than double that of supplemented heifers ( < 0.001). Control heifers reabsorbed a greater ( < 0.001) fraction of urea from the renal tubule than did supplemented heifers. Overall, unsupplemented heifers had greater

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

    PubMed

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

    2014-01-30

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  16. Serum uric acid may not be involved in the development of preeclampsia.

    PubMed

    Chen, Q; Lau, S; Tong, M; Wei, J; Shen, F; Zhao, J; Zhao, M

    2016-02-01

    Higher serum levels of uric acid are associated with preeclampsia and may signal an early change in preeclampsia. However there is less evidence suggesting there is a meaningful association between uric acid and the development of preeclampsia. A total of 877 women with preeclampsia at presentation and 580 normotensive pregnancies were retrospectively recruited from January 2009 to May 2014. In addition, 5556 pregnant women were also prospectively recruited from September 2012 to December 2013. Retrospective serum levels of uric acid were obtained from women with preeclampsia at the time of presentation (n=877), and serum levels of uric acid in the first, second and third trimester were prospectively collected in women who later developed preeclampsia (n=78), as well as those who did not (n=5478). The serum levels of uric acid were significantly increased in women with preeclampsia at presentation from retrospective samples and this increase correlated with the time of onset and the severity of preeclampsia. However, in prospective samples, serum levels of uric acid were not increased in the first and second trimesters in women who later developed preeclampsia compared with those who did not. The serum level of uric acid in the first and second trimesters in women who developed preeclampsia was not different. Our results demonstrate that the serum levels of uric acid were only increased after the presentation of clinical symptoms of preeclampsia. Therefore, it is likely that uric acid is not involved in the development of preeclampsia and cannot be an early prediction biomarker of this disease.

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

    PubMed

    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 15-40mgL(-1) with a detection limit of 13.7mgL(-1) and it was successfully used in the detection of creatinine in human urine samples.

  18. Normalization of urinary drug concentrations with specific gravity and creatinine.

    PubMed

    Cone, Edward J; Caplan, Yale H; Moser, Frank; Robert, Tim; Shelby, Melinda K; Black, David L

    2009-01-01

    Excessive fluid intake can substantially dilute urinary drug concentrations and result in false-negative reports for drug users. Methods for correction ("normalization") of drug/metabolite concentrations in urine have been utilized by anti-doping laboratories, pain monitoring programs, and in environmental monitoring programs to compensate for excessive hydration, but such procedures have not been used routinely in workplace, legal, and treatment settings. We evaluated two drug normalization procedures based on specific gravity and creatinine. These corrections were applied to urine specimens collected from three distinct groups (pain patients, heroin users, and marijuana/ cocaine users). Each group was unique in characteristics, study design, and dosing conditions. The results of the two normalization procedures were highly correlated (r=0.94; range, 0.78-0.99). Increases in percent positives by specific gravity and creatinine normalization were small (0.3% and -1.0%, respectively) for heroin users (normally hydrated subjects), modest (4.2-9.8%) for pain patients (unknown hydration state), and substantial (2- to 38-fold increases) for marijuana/cocaine users (excessively hydrated subjects). Despite some limitations, these normalization procedures provide alternative means of dealing with highly dilute, dilute, and concentrated urine specimens. Drug/metabolite concentration normalization by these procedures is recommended for urine testing programs, especially as a means of coping with dilute specimens.

  19. The amylase creatinine clearance ratio in acute pancreatitis.

    PubMed

    Murray, W R; Mackay, C

    1977-03-01

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

  20. The amylase creatinine clearance ratio in acute pancreatitis.

    PubMed

    Murray, W R; Mackay, C

    1977-03-01

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

  1. Mechanism and kinetics of electrochemical degradation of uric acid using conductive-diamond anodes.

    PubMed

    Dbira, Sondos; Bensalah, Nasr; Bedoui, Ahmed

    2016-12-01

    Uric acid (UA) is one of the principal effluents of urine wastewaters, widely used in agriculture as fertilizer, which is potentially dangerous and biorefractory. Hence, the degradation of UA (2,6,8-trihydroxy purine) in aqueous solution of pH 3.0 has been studied by conductive-diamond electrochemical oxidation. Hydroxyl radicals formed from water oxidation at the surface of boron-doped diamond anodes were the main oxidizing agents. Effects of current density and supporting electrolyte on the degradation rate and process efficiency are assessed. Results show that the increase of current density from 20 to 60 mA cm(-2) leads to a decrease in the efficiency of the electrochemical process. In addition, the best degradation occurred in the presence of NaCl as conductive electrolyte. Interestingly, an almost total mineralization of 50 ppm UA was obtained when anodic oxidation was performed at low current densities (20 mA cm(-2)) and in the presence of NaCl. This result confirmed that the electrolysis using diamond anodes is a very interesting technology for the treatment of UA. The identification of UA transformation products was performed by high-performance liquid chromatography (HPLC). HPLC analysis of treated solutions revealed that oxalic acid and urea were the two intermediates found. Oxalic acid was the most persistent product. Based on detected intermediates and bibliographic research, a mechanism of UA mineralization by anodic oxidation has been proposed. Ionic chromatography analysis confirmed the release of [Formula: see text] and [Formula: see text] ions during UA mineralization. PMID:27108970

  2. Mechanism and kinetics of electrochemical degradation of uric acid using conductive-diamond anodes.

    PubMed

    Dbira, Sondos; Bensalah, Nasr; Bedoui, Ahmed

    2016-12-01

    Uric acid (UA) is one of the principal effluents of urine wastewaters, widely used in agriculture as fertilizer, which is potentially dangerous and biorefractory. Hence, the degradation of UA (2,6,8-trihydroxy purine) in aqueous solution of pH 3.0 has been studied by conductive-diamond electrochemical oxidation. Hydroxyl radicals formed from water oxidation at the surface of boron-doped diamond anodes were the main oxidizing agents. Effects of current density and supporting electrolyte on the degradation rate and process efficiency are assessed. Results show that the increase of current density from 20 to 60 mA cm(-2) leads to a decrease in the efficiency of the electrochemical process. In addition, the best degradation occurred in the presence of NaCl as conductive electrolyte. Interestingly, an almost total mineralization of 50 ppm UA was obtained when anodic oxidation was performed at low current densities (20 mA cm(-2)) and in the presence of NaCl. This result confirmed that the electrolysis using diamond anodes is a very interesting technology for the treatment of UA. The identification of UA transformation products was performed by high-performance liquid chromatography (HPLC). HPLC analysis of treated solutions revealed that oxalic acid and urea were the two intermediates found. Oxalic acid was the most persistent product. Based on detected intermediates and bibliographic research, a mechanism of UA mineralization by anodic oxidation has been proposed. Ionic chromatography analysis confirmed the release of [Formula: see text] and [Formula: see text] ions during UA mineralization.

  3. Potential mechanisms for low uric acid in Parkinson disease.

    PubMed

    Sampat, Radhika; Young, Sarah; Rosen, Ami; Bernhard, Douglas; Millington, David; Factor, Stewart; Jinnah, H A

    2016-04-01

    Several epidemiologic studies have described an association between low serum uric acid (UA) and Parkinson disease (PD). Uric acid is a known antioxidant, and one proposed mechanism of neurodegeneration in PD is oxidative damage of dopamine neurons. However, other complex metabolic pathways may contribute. The purpose of this study is to elucidate potential mechanisms of low serum UA in PD. Subjects who met diagnostic criteria for definite or probable PD (n = 20) and controls (n = 20) aged 55-80 years were recruited. Twenty-four hour urine samples were collected from all participants, and both uric acid and allantoin were measured and corrected for body mass index (BMI). Urinary metabolites were compared using a twoway ANOVA with diagnosis and sex as the explanatory variables. There were no significant differences between PD and controls for total UA (p = 0.60), UA corrected for BMI (p = 0.37), or in the interaction of diagnosis and sex on UA (p = 0.24). Similarly, there were no significant differences between PD and controls for allantoin (p = 0.47), allantoin corrected for BMI (p = 0.57), or in the interaction of diagnosis and sex on allantoin (p = 0.78). Allantoin/UA ratios also did not significantly differ by diagnosis (p = 0.99). Our results imply that low serum UA in PD may be due to an intrinsic mechanism that alters the homeostatic set point for serum UA in PD, and may contribute to relatively lower protection against oxidative damage. These findings provide indirect support for neuroprotection trials aimed at raising serum UA.

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

    PubMed Central

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

    2012-01-01

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

  5. Extra-renal elimination of uric acid via intestinal efflux transporter BCRP/ABCG2.

    PubMed

    Hosomi, Atsushi; Nakanishi, Takeo; Fujita, Takuya; Tamai, Ikumi

    2012-01-01

    Urinary excretion accounts for two-thirds of total elimination of uric acid and the remainder is excreted in feces. However, the mechanism of extra-renal elimination is poorly understood. In the present study, we aimed to clarify the mechanism and the extent of elimination of uric acid through liver and intestine using oxonate-treated rats and Caco-2 cells as a model of human intestinal epithelium. In oxonate-treated rats, significant amounts of externally administered and endogenous uric acid were recovered in the intestinal lumen, while biliary excretion was minimal. Accordingly, direct intestinal secretion was thought to be a substantial contributor to extra-renal elimination of uric acid. Since human efflux transporter BCRP/ABCG2 accepts uric acid as a substrate and genetic polymorphism causing a decrease of BCRP activity is known to be associated with hyperuricemia and gout, the contribution of rBcrp to intestinal secretion was examined. rBcrp was confirmed to transport uric acid in a membrane vesicle study, and intestinal regional differences of expression of rBcrp mRNA were well correlated with uric acid secretory activity into the intestinal lumen. Bcrp1 knockout mice exhibited significantly decreased intestinal secretion and an increased plasma concentration of uric acid. Furthermore, a Bcrp inhibitor, elacridar, caused a decrease of intestinal secretion of uric acid. In Caco-2 cells, uric acid showed a polarized flux from the basolateral to apical side, and this flux was almost abolished in the presence of elacridar. These results demonstrate that BCRP contributes at least in part to the intestinal excretion of uric acid as extra-renal elimination pathway in humans and rats.

  6. Uric Acid: A Missing Link Between Hypertensive Pregnancy Disorders and Future Cardiovascular Disease?

    PubMed Central

    Weissgerber, Tracey L.; Milic, Natasa M.; Turner, Stephen T.; Asad, Reem A.; Mosley, Thomas H.; Kardia, Sharon L. R.; Hanis, Craig L.; Garovic, Vesna D.

    2015-01-01

    Objective To determine whether women who had a hypertensive pregnancy disorder (HPD) have elevated uric acid concentrations decades after pregnancy, when compared to women who had normotensive pregnancies. Patients and Methods The Genetic Epidemiology Network of Arteriopathy study measured uric acid concentrations in Hispanic (30%), non-Hispanic white (28%), and non-Hispanic black (42%) women (60 ± 10 years of age). This cross-sectional study was conducted between July 1, 2000 and December 31, 2004. Hispanic participants were recruited from families with high rates of diabetes, whereas non-Hispanic participants were recruited from families with high rates of hypertension. This analysis compared uric acid concentrations in women with a history of normotensive (n=1,846) or hypertensive (n=408) pregnancies by logistic regression. Results Women who had a HPD had higher uric acid concentrations (Median: 5.7 vs. 5.3 mg/dL, P<.001) and were more likely to have uric acid concentrations above 5.5 mg/dl (54.4% vs. 42.4%, P=.001) than women who had normotensive pregnancies. These differences persisted after adjusting for traditional cardiovascular risk factors, co-morbidities and other factors that affect uric acid concentrations. A family-based subgroup analysis comparing uric acid concentrations in women who had a HPD (n=308) and their parous sisters who had normotensive pregnancies (n=250) gave similar results (Median uric acid concentrations: 5.7 vs. 5.2 mg/dl, P=0.02; Proportion of women with uric acid >5.5 mg/dl: 54.0% vs. 40.3%, P<.001). Conclusion Decades after pregnancy, women who had a HPD have higher uric acid concentrations. This effect does not appear to be explained by a familial predisposition to elevated uric acid concentrations. PMID:26260220

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

    PubMed Central

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

    2013-01-01

    Degradation of purines to uric acid is generally conserved among organisms, however, the end product of uric acid degradation varies from species to species depending on the presence of active catabolic enzymes. In humans, most higher primates and birds, the urate oxidase gene is non-functional and hence uric acid is not further broken down. Uric acid in human blood plasma serves as an antioxidant and an immune enhancer; conversely, excessive amounts cause the common affliction gout. In contrast, uric acid is completely degraded to ammonia in most fungi. Currently, relatively little is known about uric acid catabolism in the fungal pathogen Cryptococcus neoformans even though this yeast is commonly isolated from uric acid-rich pigeon guano. In addition, uric acid utilization enhances the production of the cryptococcal virulence factors capsule and urease, and may potentially modulate the host immune response during infection. Based on these important observations, we employed both Agrobacterium-mediated insertional mutagenesis and bioinformatics to predict all the uric acid catabolic enzyme-encoding genes in the H99 genome. The candidate C. neoformans uric acid catabolic genes identified were named: URO1 (urate oxidase), URO2 (HIU hydrolase), URO3 (OHCU decarboxylase), DAL1 (allantoinase), DAL2,3,3 (allantoicase-ureidoglycolate hydrolase fusion protein), and URE1 (urease). All six ORFs were then deleted via homologous recombination; assaying of the deletion mutants' ability to assimilate uric acid and its pathway intermediates as the sole nitrogen source validated their enzymatic functions. While Uro1, Uro2, Uro3, Dal1 and Dal2,3,3 were demonstrated to be dispensable for virulence, the significance of using a modified animal model system of cryptococcosis for improved mimicking of human pathogenicity is discussed. PMID:23667704

  8. Precipitation diagrams and solubility of uric acid dihydrate

    NASA Astrophysics Data System (ADS)

    Babić-Ivančić, V.; Füredi-Milhofer, H.; Brown, W. E.; Gregory, T. M.

    1987-07-01

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

  9. Recent developments in glycosyl urea synthesis.

    PubMed

    McKay, Matthew J; Nguyen, Hien M

    2014-02-19

    The area of sugar urea derivatives has received considerable attention in recent years because of the unique structural properties and activities that these compounds display. The urea-linkage at the anomeric center is a robust alternative to the naturally occurring O- and N-glycosidic linkages of oligosaccharides and glycoconjugates, and the natural products that have been identified to contain these structures show remarkable biological activity. While methods for installing the β-urea-linkage at the anomeric center have been around for decades, the first synthesis of α-urea glycosides has been much more recent. In either case, the selective synthesis of glycosyl ureas can be quite challenging, and a mixture of α- and β-isomers will often result. This paper will provide a comprehensive review of the synthetic approaches to α- and β-urea glycosides and examine the structure and activity of the natural products and their analogues that have been identified to contain them.

  10. Mendelian randomization analysis associates increased serum urate, due to genetic variation in uric acid transporters, with improved renal function.

    PubMed

    Hughes, Kim; Flynn, Tanya; de Zoysa, Janak; Dalbeth, Nicola; Merriman, Tony R

    2014-02-01

    Increased serum urate predicts chronic kidney disease independent of other risk factors. The use of xanthine oxidase inhibitors coincides with improved renal function. Whether this is due to reduced serum urate or reduced production of oxidants by xanthine oxidase or another physiological mechanism remains unresolved. Here we applied Mendelian randomization, a statistical genetics approach allowing disentangling of cause and effect in the presence of potential confounding, to determine whether lowering of serum urate by genetic modulation of renal excretion benefits renal function using data from 7979 patients of the Atherosclerosis Risk in Communities and Framingham Heart studies. Mendelian randomization by the two-stage least squares method was done with serum urate as the exposure, a uric acid transporter genetic risk score as instrumental variable, and estimated glomerular filtration rate and serum creatinine as the outcomes. Increased genetic risk score was associated with significantly improved renal function in men but not in women. Analysis of individual genetic variants showed the effect size associated with serum urate did not correlate with that associated with renal function in the Mendelian randomization model. This is consistent with the possibility that the physiological action of these genetic variants in raising serum urate correlates directly with improved renal function. Further studies are required to understand the mechanism of the potential renal function protection mediated by xanthine oxidase inhibitors.

  11. Urinary creatinine concentrations in the U.S. population: implications for urinary biologic monitoring measurements.

    PubMed

    Barr, Dana B; Wilder, Lynn C; Caudill, Samuel P; Gonzalez, Amanda J; Needham, Lance L; Pirkle, James L

    2005-02-01

    Biologic monitoring (i.e., biomonitoring) is used to assess human exposures to environmental and workplace chemicals. Urinary biomonitoring data typically are adjusted to a constant creatinine concentration to correct for variable dilutions among spot samples. Traditionally, this approach has been used in population groups without much diversity. The inclusion of multiple demographic groups in studies using biomonitoring for exposure assessment has increased the variability in the urinary creatinine levels in these study populations. Our objectives were to document the normal range of urinary creatinine concentrations among various demographic groups, evaluate the impact that variations in creatinine concentrations can have on classifying exposure status of individuals in epidemiologic studies, and recommend an approach using multiple regression to adjust for variations in creatinine in multivariate analyses. We performed a weighted multivariate analysis of urinary creatinine concentrations in 22,245 participants of the Third National Health and Nutrition Examination Survey (1988-1994) and established reference ranges (10th-90th percentiles) for each demographic and age category. Significant predictors of urinary creatinine concentration included age group, sex, race/ethnicity, body mass index, and fat-free mass. Time of day that urine samples were collected made a small but statistically significant difference in creatinine concentrations. For an individual, the creatinine-adjusted concentration of an analyte should be compared with a "reference" range derived from persons in a similar demographic group (e.g., children with children, adults with adults). For multiple regression analysis of population groups, we recommend that the analyte concentration (unadjusted for creatinine) should be included in the analysis with urinary creatinine added as a separate independent variable. This approach allows the urinary analyte concentration to be appropriately adjusted for

  12. Serum Creatinine Versus Plasma Methotrexate Levels to Predict Toxicities in Children Receiving High-dose Methotrexate.

    PubMed

    Tiwari, Priya; Thomas, M K; Pathania, Subha; Dhawan, Deepa; Gupta, Y K; Vishnubhatla, Sreenivas; Bakhshi, Sameer

    2015-01-01

    Facilities for measuring methotrexate (MTX) levels are not available everywhere, potentially limiting administration of high-dose methotrexate (HDMTX). We hypothesized that serum creatinine alteration after HDMTX administration predicts MTX clearance. Overall, 122 cycles in 50 patients of non-Hodgkin lymphoma or acute lymphoblastic leukemia aged ≤18 years receiving HDMTX were enrolled prospectively. Plasma MTX levels were measured at 12, 24, 36, 48, 60, and 72 hours; serum creatinine was measured at baseline, 24, 48, and 72 hours. Correlation of plasma MTX levels with creatinine levels and changes in creatinine from baseline (Δ creatinine) were evaluated. Plasma MTX levels at 72 hours showed positive correlation with serum creatinine at 48 hours (P = .011) and 72 hours (P = .013) as also Δ creatinine at 48 hours (P = .042) and 72 hours (P = .045). However, cut-off value of either creatinine or Δ creatinine could not be established to reliably predict delayed MTX clearance. Greater than 50% Δ creatinine at 48 and 72 hours significantly predicted grade 3/4 leucopenia (P = .036 and P = .001, respectively) and thrombocytopenia (P = .012 and P = .009, respectively) but not mucositis (P = .827 and P = .910, respectively). Delayed MTX elimination did not predict any grade 3/4 toxicity. In spite of demonstration of significant correlation between serum creatinine and Δ creatinine with plasma MTX levels at 72 hours, cut-off value of either variable to predict MTX delay could not be established. Thus, either of these cannot be used as a surrogate for plasma MTX estimation. Interestingly, Δ creatinine effectively predicted hematological toxicities, which were not predicted by delayed MTX clearance.

  13. High serum creatinine nonlinearity: a renal vital sign?

    PubMed

    Palant, Carlos E; Chawla, Lakhmir S; Faselis, Charles; Li, Ping; Pallone, Thomas L; Kimmel, Paul L; Amdur, Richard L

    2016-08-01

    Patients with chronic kidney disease (CKD) may have nonlinear serum creatinine concentration (SC) trajectories, especially as CKD progresses. Variability in SC is associated with renal failure and death. However, present methods for measuring SC variability are unsatisfactory because they blend information about SC slope and variance. We propose an improved method for defining and calculating a patient's SC slope and variance so that they are mathematically distinct, and we test these methods in a large sample of US veterans, examining the correlation of SC slope and SC nonlinearity (SCNL) and the association of SCNL with time to stage 4 CKD (CKD4) and death. We found a strong correlation between SCNL and rate of CKD progression, time to CKD4, and time to death, even in patients with normal renal function. We therefore argue that SCNL may be a measure of renal autoregulatory dysfunction that provides an early warning sign for CKD progression. PMID:27194712

  14. Creatinine biomaterial thin films grown by laser techniques.

    PubMed

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

    2008-03-01

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

  15. Urea and its formation in coelacanth liver.

    PubMed

    Brown, G W; Brown, S G

    1967-02-01

    Urea occurs in liver of the coelacanth Latimeria chalumnae to the extent of about 1.7 percent by weight. It was determined quantitatively by reaction with 1-phenyl-1,2-propanedione-2-oxime (Archibald reagent) and by measurement of ammonia released upon treatment with urease. Arginase and ornithine carbamoyltransferase, enzymes instrumental in the formation of urea in typical ureotelic vertebrates, occur in homogenates of coelacanth liver. Formed in part by the ornithine-urea cycle, urea may have an osmoregulatory function in the coelacanth as it has in elasmobranchs.

  16. Xanthine oxidase-mediated denitrosation of N-nitroso-tryptophan by superoxide and uric acid.

    PubMed

    Viles, Kimberley; Mathai, Clinton; Jourd'heuil, Frances L; Jourd'heuil, David

    2013-01-15

    Recent studies indicate the formation of protein nitrosamines in vivo and tryptophan residues in proteins might represent important targets of nitrosative and oxidative stress. In the present work, we examined the mechanism by which xanthine oxidase (XO) denitrosates N-nitroso Trp residues and determined the applicability of the reactions involved to the detection of nitrosated Trp residues by tri-iodide-based chemiluminescence. We found that - in addition to superoxide - denitrosation of N-acetyl-nitroso Trp (NANT) by hypoxanthine and XO occurred via the intermediacy of uric acid. Zero-order dependence of NANT decay rate with uric acid was achieved with increasing concentrations of uric acid (k(0)∼6.0×10(-4)s(-1)) and generated nitric oxide. In contrast, S-nitrosoglutathione and nitrosyl-myoglobin were stable in the presence of uric acid. NANT decomposition by uric acid could be reproducibly measured using the tri-iodide-based chemiluminescence assay in the presence of excess nitrite upon pre-treatment with acidified sulfanilamide. N-nitrosated albumin was sensitive to uric acid-induced decomposition only after proteolytic degradation. In conclusion, XO decomposes nitrosated Trp through superoxide and uric acid pathways and in the case of uric acid generates free nitric oxide. Site-specificity of this reaction may possibly be used in combination with the tri-iodide-based chemiluminescence assay to discern between nitrosated Trp, S-nitrosothiols, and nitrosylated heme proteins. PMID:23099296

  17. The role of uric acid in the pathogenesis of hypertension in the young.

    PubMed

    Feig, Daniel I

    2012-06-01

    Uric acid has been suspected to be a risk factor for hypertension since the 1870s. Numerous epidemiological studies demonstrate an association between uric acid and both incident and prevalent hypertension in diverse populations. Studies in elderly patients have had more variable results, raising the possibility that uric acid may be more significant to hypertension in the young. Animal models support a two-phase mechanism for the development of hyperuricemic hypertension. Initially, uric acid induces vasoconstriction by activation of the renin-angiotensin system and reduction of circulating nitric oxide, which can be reversed by lowering uric acid. Over time, uric acid uptake into vascular smooth muscle cells causes cellular proliferation and secondary arteriolosclerosis that impairs pressure natriuresis, causing sodium-sensitive hypertension. Consistent with the animal model data, small clinical trials performed in adolescents with newly diagnosed essential hypertension demonstrate that at least in certain young patients, reduction of serum uric acid can mitigate blood pressure elevation. While more research is clearly necessary, the available data suggest that uric acid is likely causative in some cases of early-onset hypertension.

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

    PubMed Central

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

    2016-01-01

    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

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

    PubMed

    Kim, Jayoung; Imani, Somayeh; de Araujo, William R; Warchall, Julian; Valdés-Ramírez, Gabriela; Paixão, 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.

  20. Stored wheat insect infestation related to uric acid as determined by liquid chromatography.

    PubMed

    Wehling, R L; Wetzel, D L; Pedersen, J R

    1984-01-01

    Liquid chromatography is used to measure the uric acid content of wheat internally infested by various growth stages of granary weevil (Sitophilus granarius), rice weevil (Sitophilus oryzae), and lesser grain borer (Ryzopertha dominica). Good correlation exists between numbers of insects and uric acid content of grain infested by a given stage of an internally infesting stored product insect, with correlation coefficients ranging from 0.970 to 0.998. Uric acid content of infested grain increases as the insect life cycle progresses, with granary weevil producing the greatest quantities of uric acid followed in order by rice weevil and lesser grain borer. A detection limit for the analytical procedure of less than 1.0 ppm uric acid allows detection of infestation levels as low as one kernel per 100 g grain for late instar granary weevil larvae. This limit is sufficiently sensitive to detect levels of infestation that may be commonly encountered in commerce.

  1. Luteolin prevents uric acid-induced pancreatic β-cell dysfunction

    PubMed Central

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

    2014-01-01

    Abstract Elevated uric acid causes direct injury to pancreatic β-cells. In this study, we examined the effects of luteolin, an important antioxidant, on uric acid-induced β-cell dysfunction. We first evaluated the effect of luteolin on nitric oxide (NO) formation in uric acid-stimulated Min6 cells using the Griess method. Next, we performed transient transfection and reporter assays to measure transcriptional activity of nuclear factor (NF)-κB. Western blotting assays were also performed to assess the effect of luteolin on the expression of MafA and inducible NO synthase (iNOS) in uric acid-treated cells. Finally, we evaluated the effect of luteolin on uric acid-induced inhibition of glucose-stimulated insulin secretion (GSIS) in Min6 cells and freshly isolated mouse pancreatic islets. We found that luteolin significantly inhibited uric acid-induced NO production, which was well correlated with reduced expression of iNOS mRNA and protein. Furthermore, decreased activity of NF-κB was implicated in inhibition by luteolin of increased iNOS expression induced by uric acid. Besides, luteolin significantly increased MafA expression in Min6 cells exposed to uric acid, which was reversed by overexpression of iNOS. Moreover, luteolin prevented uric acid-induced inhibition of GSIS in both Min6 cells and mouse islets. In conclusion, luteolin protects pancreatic β-cells from uric acid-induced dysfunction and may confer benefit on the protection of pancreatic β-cells in hyperuricemia-associated diabetes. PMID:25050113

  2. Effect of Diet on Serum Creatinine in Healthy Subjects During a Phase I Study

    PubMed Central

    Pimenta, Eduardo; Jensen, Markus; Jung, David; Schaumann, Frank; Boxnick, Stefanie; Truebel, Hubert

    2016-01-01

    Creatinine is widely used as an indirect marker of renal function. However, interfering factors such as diet, exercise and problems with the assay can generate false results and misinterpretation of real kidney function. In this article, we report the dietary effects on serum creatinine during a phase I single dose escalation study and discuss the reasons why serum creatinine should be measured under fasting conditions. PMID:27738487

  3. The screening value of the amylase-creatinine clearance ratio in acute pancreatitis.

    PubMed

    Van Hee, R; Hubens, A

    1979-01-01

    The screening value of the amylase creatinine clearance ratio in acute pancreatitis is studied. A series of 28 patients with pancreatic disease is compared with 80 controls and 82 patients with other intra-abdominal disease. The greatest specificity of the amylase creatinine clearance ratio value is reached at the 3.5 level. The amylase creatinine clearance ratio value proves to be of interest, not only in the diagnosis of acute pancreatitis but also in differentiating mild and heavy forms of pancreatitis.

  4. ["Occult" renal insufficiency due to evaluating renal function using only serum creatinine].

    PubMed

    Fernández-Fresnedo, G; de Francisco, A L M; Rodrigo, E; Piñera, C; Herráez, I; Ruiz, J C; Arias, M

    2002-01-01

    Timely referral to nephrologists depends on identification of renal failure. Most primary care physicians and specialists rely on serum creatinine as the standard test for determination of renal function. Creatinine clearance requires 24 hours urine collection with many pitfalls and wrong results. We compare serum creatinine and the Cockcroft-Gault (C-G) equation as measure of glomerular filtration rate (GFR). The study included 1,053 outpatients with serum creatinine lower than 2.5 mg/dl referred to our nephrological laboratory for serum creatinine and GFR determination using the C-G formula. Patients were grouped into two groups: normal renal function (serum creatinine < 1.3 mg/dl) and "incipient" abnormal renal function (serum creatinine 1.3-2.5 mg/dl). In the group of females with normal creatinine 22% (60-70 y), 35% (70-80 y) and 57% (> 80 y) had GFR values below 50 ml/min. In the group of males 11.3% (70-80 y) and 33.3% (> 80 y) also had GFR reduction in spite of normal serum creatinine. A severe renal insufficiency with creatinine clearance lower than 30 ml/min was observed in the group with "incipient" renal failure based on serum creatinine: 22.7%, 40% and 82.9% for females and 6%, 22.7% and 57% for male (60-70 y; 70-80 y; and > 80 y respectively). In order to improve management and prevention of renal failure appropriate measurements of renal function other than serum creatinine should be emphasize.

  5. Cystatin C, creatinine, estimated glomerular filtration, and long-term mortality in stroke patients.

    PubMed

    Hojs Fabjan, Tanja; Penko, Meta; Hojs, Radovan

    2014-02-01

    Renal dysfunction is associated with mortality in patients after ischemic stroke. Cystatin C is a potentially superior marker of renal function compared to creatinine and estimated glomerular filtration rate (GFR). In our observational cohort study, 390 Caucasian patients suffered from acute ischemic stroke (mean age 70.9 years; 183 women and 207 men) were included and prospectively followed up to maximal 56 months. Serum creatinine and cystatin C were measured at admission to the hospital; GFR was estimated according to CKD-EPI creatinine and CKD-EPI creatinine/cystatin equations. According to values of serum creatinine, estimated GFR and serum cystatin C patients were divided into quintiles. In the follow-up period, 191 (49%) patients died. For serum cystatin C and estimated GFR based on creatinine and cystatin C, the mortality and the hazard ratios for long-term mortality increased from the first to the fifth quintile nearly linearly. The associations of serum creatinine and estimated GFR categories based on creatinine with long-term mortality were J-shaped. As compared with lowest quintile of serum cystatin C, the fifth quintile was associated with long-term mortality significantly also after multivariate adjustment (age, gender, initial stroke severity, known risk factors for stroke mortality). In contrast, in adjusted analysis serum creatinine and estimated GFR (CKD-EPI creatinine and CKD-EPI creatinine/cystatin) were not associated with long-term mortality. In summary, serum cystatin C was independently and better associated with the risk of long-term mortality in patients suffering from ischemic stroke than were creatinine and estimated GFR using both CKD-EPI equations.

  6. Urea Transporter Physiology Studied in Knockout Mice

    PubMed Central

    Li, Xuechen; Chen, Guangping; Yang, Baoxue

    2012-01-01

    In mammals, there are two types of urea transporters; urea transporter (UT)-A and UT-B. The UT-A transporters are mainly expressed in kidney epithelial cells while UT-B demonstrates a broader distribution in kidney, heart, brain, testis, urinary tract, and other tissues. Over the past few years, multiple urea transporter knockout mouse models have been generated enabling us to explore the physiological roles of the different urea transporters. In the kidney, deletion of UT-A1/UT-A3 results in polyuria and a severe urine concentrating defect, indicating that intrarenal recycling of urea plays a crucial role in the overall capacity to concentrate urine. Since UT-B has a wide tissue distribution, multiple phenotypic abnormalities have been found in UT-B null mice, such as defective urine concentration, exacerbated heart blockage with aging, depression-like behavior, and earlier male sexual maturation. This review summarizes the new insights of urea transporter functions in different organs, gleaned from studies of urea transporter knockout mice, and explores some of the potential pharmacological prospects of urea transporters. PMID:22745630

  7. 40 CFR 721.9892 - Alkylated urea.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylated urea. 721.9892 Section 721.9892 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9892 Alkylated urea. (a) Chemical...

  8. 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....

  9. [Urea formation in the after operational liver].

    PubMed

    Savilov, P N

    2016-01-01

    The effect of resection of the left lobe of the liver (LR, 15-20% og the organ weight) on hepatic urea formation was investigated in 84 albino rats. The objects of study were the surgery left (LLP), inoperable middle (MLP) lobe of the liver, blood (aorta, v. hepatica, v. porta) and choledochal bile. They studied the urea content. Arginase activity was examined in liver homogenate. On the day 3 and day 7 after resection reduced arginase activity was detected. LR caused a decrease of urea in v. hepatica, but increased urea content in the arterial blood and v. porta. Increase in bile urea on day 7 it was replaced by a decrease observed on day 14 of the postsurgery period. The concentration of urea in the liver on the 3rd day after LR was below the norm, and on the 7th and 14th day was within it. The results indicate a violation of urea operated by hepatocytes of the liver and extrahepatic activation mechanisms of the formation of urea.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Effect of creatinine and specific gravity normalization on urinary biomarker 1,6-hexamethylene diamine.

    PubMed

    Gaines, Linda G T; Fent, Kenneth W; Flack, Sheila L; Thomasen, Jennifer M; Ball, Louise M; Zhou, Haibo; Whittaker, Stephen G; Nylander-French, Leena A

    2010-03-01

    Urine amine levels used as biomarkers of diisocyanate exposure have usually been normalized with creatinine concentration. The suitability of using creatinine concentration or specific gravity for these biomarkers in exposure assessment has not been established. We investigated the effect of creatinine concentration and specific gravity on urine 1,6-hexamethylene diamine (HDA) levels in multiple mixed linear regression models using quantitative dermal and inhalation exposure data derived from a survey of automotive spray painters occupationally exposed to 1,6-hexamethylene diisocyanate (HDI). Painters' dermal and breathing-zone HDI exposure were monitored for an entire workday for up to three workdays spaced approximately one month apart. One urine sample was collected before the start of work with HDI-containing paints, and multiple samples were collected throughout the workday. Both creatinine concentration and specific gravity were highly significant predictors (p < 0.0001) of urine HDA levels. When these two were used together in the same model, creatinine remained highly significant (p < 0.0001), but specific gravity decreased in significance (p-values 0.10-0.17). We used different individual factors to determine which affected creatinine and specific gravity. Urine collection time was a highly significant predictor of specific gravity (p = 0.003) and creatinine concentration (p = 0.001). Smoker status was significant (p = 0.026) in the creatinine model. The findings indicate that creatinine concentration is more appropriate to account for urine water content than specific gravity and that creatinine is best used as an independent variable in HDI exposure assessment models instead of traditional urine normalization with creatinine concentration.

  15. An exploratory study of serum creatinine levels in patients with amyotrophic lateral sclerosis.

    PubMed

    Chen, Xueping; Guo, Xiaoyan; Huang, Rui; Zheng, Zhenzhen; Chen, Yongping; Shang, Hui-Fang

    2014-10-01

    The etiology of amyotrophic lateral sclerosis (ALS) remains unknown, but existing data argue for a role of creatinine in ALS pathophysiology. Our aim is to clarify the correlation between serum creatinine and ALS in Chinese population. A total of 512 sporadic ALS (SALS) patients and 501 age- and gender-matched healthy controls were included. Revised ALS Functional Rating Scale (ALS-FRS-R) was used to assess the motor functional status of SALS patients. Survival analysis was performed using Kaplan-Meier method. Serum creatinine levels were significantly lower in SALS patients than in controls (p < 0.001). Patients with the second, the third and highest quartiles of creatinine levels had a significantly lower presence of ALS compared to those with the lowest quartile (p for trend <0.001). However, decreased presence of ALS was not found in the highest quartiles compared with the lowest quartiles in females. Sporadic ALS patients with different site of onset have similar serum creatinine levels, but underweight patients presented lower levels of serum creatinine. Patients with low serum creatinine levels are more likely to have severe motor impairment and low body mass index (BMI) values. This study demonstrates that SALS patients have lower serum creatinine levels than well-matched controls. Higher levels of serum creatinine are less likely to be associated with the presence of ALS in Chinese populations. Low serum creatinine levels may be related to severe motor impairment in SALS patients, after adjusting the confounding factor-BMI. However, serum creatinine has no deleterious impact on survival in ALS.

  16. The amylase-creatinine clearance ratio following cardiopulmonary bypass.

    PubMed

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

    1981-08-01

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

  17. Evaluation of dementia by acrolein, amyloid-β and creatinine.

    PubMed

    Igarashi, Kazuei; Yoshida, Madoka; Waragai, Masaaki; Kashiwagi, Keiko

    2015-10-23

    Plasma, urine and cerebrospinal fluid (CSF) were examined for biochemical markers of dementia. Protein-conjugated acrolein (PC-Acro) and the amyloid-β (Aβ)40/42 ratio in plasma can be used to detect mild cognitive impairment (MCI) and Alzheimer's disease (AD). In plasma, PC-Acro and the Aβ40/42 ratio in MCI and AD were significantly higher relative to non-demented subjects. Furthermore, urine acrolein metabolite, 3-hydroxypropyl mercapturic acid (3-HPMA)/creatinine (Cre) and amino acid-conjugated acrolein (AC-Acro)/Cre in AD were significantly lower than MCI. It was also shown that reduced urine 3-HPMA/Cre correlated with increased plasma Aβ40/42 ratio in dementia. The Aβ40/PC-Acro ratio in CSF, together with Aβ40 and Aβ40/42 ratio, was lower in AD than MCI. Increased plasma PC-Acro and Aβ40/42 ratio and decreased urine 3-HPMA/Cre correlated with cognitive ability (MMSE). These results indicate that the measurements of acrolein derivatives together with Aβ and Cre in biologic fluids is useful to estimate severity of dementia.

  18. The amylase-creatinine clearance ratio following cardiopulmonary bypass.

    PubMed

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

    1981-08-01

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

  19. Biological Activities of Uric Acid in Infection Due to Enteropathogenic and Shiga-Toxigenic Escherichia coli

    PubMed Central

    Broome, Jacqueline E.; Lis, Agnieszka

    2016-01-01

    In previous work, we identified xanthine oxidase (XO) as an important enzyme in the interaction between the host and enteropathogenic Escherichia coli (EPEC) and Shiga-toxigenic E. coli (STEC). Many of the biological effects of XO were due to the hydrogen peroxide produced by the enzyme. We wondered, however, if uric acid generated by XO also had biological effects in the gastrointestinal tract. Uric acid triggered inflammatory responses in the gut, including increased submucosal edema and release of extracellular DNA from host cells. While uric acid alone was unable to trigger a chloride secretory response in intestinal monolayers, it did potentiate the secretory response to cyclic AMP agonists. Uric acid crystals were formed in vivo in the lumen of the gut in response to EPEC and STEC infections. While trying to visualize uric acid crystals formed during EPEC and STEC infections, we noticed that uric acid crystals became enmeshed in the neutrophilic extracellular traps (NETs) produced from host cells in response to bacteria in cultured cell systems and in the intestine in vivo. Uric acid levels in the gut lumen increased in response to exogenous DNA, and these increases were enhanced by the actions of DNase I. Interestingly, addition of DNase I reduced the numbers of EPEC bacteria recovered after a 20-h infection and protected against EPEC-induced histologic damage. PMID:26787720

  20. 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.

  1. 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.

  2. Preterm Birth is Associated with Higher Uric Acid Levels in Adolescents

    PubMed Central

    Washburn, Lisa K.; Nixon, Patricia A.; Russell, Gregory B.; Snively, Beverly M.; O’Shea, T. Michael

    2015-01-01

    Objective To compare serum uric acid levels in adolescents born prematurely and adolescents born at term and to assess the correlation between serum uric acid and blood pressure in those born prematurely. Study design In this observational cohort study, 124 adolescents born prematurely and 44 adolescents born at term were studied at 14 years of age. Multivariate analyses were used to describe the relationship of premature birth to serum uric acid, while adjusting for confounding variables. Pearson correlation was used to describe the relationship between uric acid and systolic blood pressure among those born prematurely. Results Adjusting for race, sex, maternal hypertension and fetal growth, preterm adolescents had higher serum uric acid levels than adolescents born at term [adjusted mean difference (95% confidence interval: 0.46 (0.10, 0.81) mg/dL, 27.4 (6, 48.2) μmol/L, p=0.012]. Among those born prematurely, uric acid was positively correlated with systolic blood pressure [Pearson correlation coefficient: 0.29 (0.12, 0.44; p= 0.0013). Conclusions Serum uric acid levels are higher in adolescents born prematurely than in those born at term and this difference could contribute to higher blood pressure among individuals born prematurely. PMID:25868431

  3. 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

  4. Perfluoroalkyl chemicals and elevated serum uric acid in US adults

    PubMed Central

    Shankar, Anoop; Xiao, Jie; Ducatman, Alan

    2011-01-01

    Background: Perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, are man-made chemicals that have been detected in the blood of over 98% of the US population. Serum uric acid is a novel biomarker, even mild elevations of which has been implicated in the development of hypertension, diabetes mellitus, cardiovascular disease, and chronic kidney disease. We examined the relationship of serum perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, and elevated uric acid levels in a representative sample of US adults. Methods: We examined 3883 participants from the 1999–2000 and 2003–2006 National Health and Nutritional Examination Surveys, a representative, multiethnic population-based survey of noninstitutionalized US adults. Serum perfluorooctanoic acid and perfluorooctane sulfonate were analyzed as quartiles. The main outcome was hyperuricemia. Results: We found that serum levels of perfluoroalkyl chemicals, including perfluorooctanoic acid and perfluorooctane sulfonate, were positively associated with hyperuricemia. This association appeared to be independent of confounders such as age, gender, race-ethnicity, body mass index, diabetes, hypertension, and serum cholesterol. Compared with subjects in quartile 1 (referent), the multivariate odds ratio for hyperuricemia among subjects in quartile 4 was 1.97 (95% confidence interval 1.44–2.70, P < 0.0001) for perfluorooctanoic acid and 1.48% (95% confidence interval 0.99–2.22, P = 0.0433) for perfluorooctane sulfonate. This observed association persisted in subgroup analysis by gender and body mass index. Conclusion: Our results demonstrate that elevated levels of perfluoroalkyl chemicals are associated with hyperuricemia even at low perfluoroalkyl chemical exposure levels as seen in the US general population. PMID:22003309

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

    NASA Technical Reports Server (NTRS)

    Rho, J. H.

    1967-01-01

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

  6. Serum Creatinine Detection by a Conducting Polymer Based Electrochemical Sensor to Identify Allograft Dysfunction

    PubMed Central

    Wei, Fang; Cheng, Scott; Korin, Yael; Reed, Elaine F.; Gjertson, David; Ho, Chih-ming; Gritsch, H. Albin; Veale, Jeffrey

    2015-01-01

    Kidney transplant recipients who have abnormally high creatinine levels in their blood often have allograft dysfunction secondary to rejection. Creatinine has become the preferred marker for renal dysfunction and is readily available in hospital clinical settings. We developed a rapid and accurate polymer-based electrochemical point-of-care (POC) assay for creatinine detection from whole blood to identify allograft dysfunction. The creatinine concentrations of 19 blood samples from transplant recipients were measured directly from clinical serum samples by the conducting polymer based electrochemical (EC) sensor arrays. These measurements were compared to the traditional clinical laboratory assay. The time required for detection was less than 5 minutes from sample loading. Sensitivity of the detection was found to be 0.46 mg/dL of creatinine with only 40 μL sample in the creatinine concentration range of 0 mg/dL to 11.33 mg/dL. Signal levels that were detected electrochemically correlated closely with the creatinine blood concentration detected by the UCLA Ronald Reagan Medical Center traditional clinical laboratory assay (correlation coefficient 0.94). This work is encouraging for the development of a rapid and accurate POCT device for measuring creatinine levels in whole blood. PMID:22881369

  7. 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.

  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. Impact of urea on detergent micelle properties.

    PubMed

    Broecker, Jana; Keller, Sandro

    2013-07-01

    Co-solvents, such as urea, can entail drastic changes in the micellization behavior of detergents. We present a systematic quantification of the impact of urea on the critical micellar concentration, the micellization thermodynamics, and the micelle size in three homologous series of commonly used non-ionic alkyl detergents. To this end, we performed demicellization experiments by isothermal titration calorimetry and hydrodynamic size measurements by dynamic light scattering on alkyl maltopyranosides, cyclohexyl alkyl maltopyranosides, and alkyl glucopyranosides at urea concentrations of 0-8 M. For all detergents studied, we found that the critical micellar concentration increases exponentially because the absolute Gibbs free energy of micellization decreases linearly over the entire urea concentration range, as does the micelle size. In contrast, the enthalpic and entropic contributions to micellization reveal more complex, nonlinear dependences on urea concentration. Both free energy and size changes are more pronounced for long-chain detergents, which bury more apolar surface area upon micelle formation. The Gibbs free energy increments per methylene group within each detergent series depend on urea concentration in a linear fashion, although they result from the entropic term for alkyl maltosides but are of enthalpic origin for cyclohexyl alkyl maltosides. We compare our results to transfer free energies of amino acid side chains, relate them to protein-folding data, and discuss how urea-induced changes in detergent micelle properties affect in vitro investigations on membrane proteins.

  10. Point of care creatinine measurement for diagnosis of renal disease using a disposable microchip.

    PubMed

    Ávila, Mónica; Floris, Arjan; Staal, Steven; Ríos, Ángel; Eijkel, Jan; van den Berg, Albert

    2013-11-01

    A point-of-care device for the determination of elevated creatinine levels in blood is reported. This device potentially offers a new and simple clinical regime for the determination of creatinine that will give huge time savings and removal of several steps of determination. The test employs a disposable prefilled microchip and the handheld Medimate Multireader®. By optimizing the analytical conditions it was found that the LOD of the proposed method was 87 μM creatinine, close to the normal human serum levels that are in the range of 60 to 100 μM. A statistical analysis of the residual shows a normal distribution, indicating the absence of systematic errors in the proposed method. The test can be used to distinguish patients with renal insufficiency (creatinine levels >100 μM) from healthy persons. Long-term monitoring could furthermore distinguish between acute renal failure and chronic kidney disease by the rate of creatinine concentration rise.

  11. Effect of urea on biomimetic aggregates.

    PubMed

    Florenzano, F H; Politi, M J

    1997-02-01

    The effect of urea on biomimetic aggregates (aqueous and reversed micelles, vesicles and monolayers) was investigated to obtain insights into the effect of the denaturant on structured macromolecules. Direct evidence obtained from light scattering (static and dynamic), monolayer maximum isothermal compression and ionic conductivity measurements, together with indirect evidence from fluorescence photodissociation, fluorescence suppression, and thermal reactions, strongly indicates the direct interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied), which leads to an increase in the area per headgroup and also in the loss of counterion affinities. PMID:9239302

  12. Dried blood spot analysis of creatinine with LC-MS/MS in addition to immunosuppressants analysis.

    PubMed

    Koster, Remco A; Greijdanus, Ben; Alffenaar, Jan-Willem C; Touw, Daan J

    2015-02-01

    In order to monitor creatinine levels or to adjust the dosage of renally excreted or nephrotoxic drugs, the analysis of creatinine in dried blood spots (DBS) could be a useful addition to DBS analysis. We developed a LC-MS/MS method for the analysis of creatinine in the same DBS extract that was used for the analysis of tacrolimus, sirolimus, everolimus, and cyclosporine A in transplant patients with the use of Whatman FTA DMPK-C cards. The method was validated using three different strategies: a seven-point calibration curve using the intercept of the calibration to correct for the natural presence of creatinine in reference samples, a one-point calibration curve at an extremely high concentration in order to diminish the contribution of the natural presence of creatinine, and the use of creatinine-[(2)H3] with an eight-point calibration curve. The validated range for creatinine was 120 to 480 μmol/L (seven-point calibration curve), 116 to 7000 μmol/L (1-point calibration curve), and 1.00 to 400.0 μmol/L for creatinine-[(2)H3] (eight-point calibration curve). The precision and accuracy results for all three validations showed a maximum CV of 14.0% and a maximum bias of -5.9%. Creatinine in DBS was found stable at ambient temperature and 32 °C for 1 week and at -20 °C for 29 weeks. Good correlations were observed between patient DBS samples and routine enzymatic plasma analysis and showed the capability of the DBS method to be used as an alternative for creatinine plasma measurement.

  13. Mechanisms Underpinning Increased Plasma Creatinine Levels in Patients Receiving Vemurafenib for Advanced Melanoma

    PubMed Central

    Hurabielle, Charlotte; Pillebout, Evangéline; Stehlé, Thomas; Pagès, Cécile; Roux, Jennifer; Schneider, Pierre; Chevret, Sylvie; Chaffaut, Cendrine; Boutten, Anne; Mourah, Samia; Basset-Seguin, Nicole; Vidal-Petiot, Emmanuelle; Lebbé, Céleste; Flamant, Martin

    2016-01-01

    Context Serum creatinine has been reported to increase in patients receiving Vemurafenib, yet neither the prevalence nor the mechanism of this adverse event are known. Objective We aimed to evaluate the frequency and the mechanisms of increases in plasma creatinine level in patients receiving Vemurafenib for advanced melanoma. Methods We performed a retrospective monocentric study including consecutive patients treated with Vemurafenib for an advanced melanoma. We collected clinical and biological data concerning renal function before introduction of Vemurafenib and in the course of monthly follow-up visits from March 2013 to December 2014. Cystatin C-derived glomerular filtration rate was evaluated before and after Vemurafenib initiation, as increase in serum cystatin C is specific to a decrease in the glomerular filtration rate. We also performed thorough renal explorations in 3 patients, with measurement of tubular secretion of creatinine before and after Vemurafenib initiation and a renal biopsy in 2 patients. Results 70 patients were included: 97% of them displayed an immediate, and thereafter stable, increase in creatinine (+22.8%) after Vemurafenib initiation. In 44/52 patients in whom Vemurafenib was discontinued, creatinine levels returned to baseline. Serum cystatin C increased, although proportionally less than serum creatinine, showing that creatinine increase under vemurafenib was indeed partly due to a renal function impairment. In addition, renal explorations demonstrated that Vemurafenib induced an inhibition of creatinine tubular secretion. Conclusion Thus, Vemurafenib induces a dual mechanism of increase in plasma creatinine with both an inhibition of creatinine tubular secretion and slight renal function impairment. However, this side effect is mostly reversible when Vemurafenib is discontinued, and should not lead physicians to discontinue the treatment if it is effective. PMID:26930506

  14. [Advance in treatment of hyperuricemia by Chinese medicine based on uric acid transporterome].

    PubMed

    Zhou, Qi; Liu, Shu-min

    2015-11-01

    With the development of the quality of life, the morbidity of hyperuricemia is increasing year by year. At the same time, it appears that this disease attacks the young people currently. As the study of pathogenesis of hyperuricemia advanced, a series of uric acid transporters were found during this process. Meanwhile, the definition of transporterome was proposed. They were divided into three groups according to the functions: reabsorption proteins, excretion proteins and skeleton proteins. At moment, the drugs for hyperuricmia mainly include uric acid composition inhibitors and uric acid excretion promoters. Since the excretion of uric acid plays a leading role during the process of attack of hyperurecimia, it makes sense to explore Chinese medicines with clear mechanism targeting the transporterome. Therefore, this paper would focus on transporterome and summarize the mechanisms of Chinese medicines in treating hyperuricemia.

  15. 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.

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Detection of Interstellar Urea with Carma

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  1. Establishment of Biological Reference Intervals and Reference Curve for Urea by Exploratory Parametric and Non-Parametric Quantile Regression Models

    PubMed Central

    2013-01-01

    Background: The validity of the entire renal function tests as a diagnostic tool depends substantially on the Biological Reference Interval (BRI) of urea. Establishment of BRI of urea is difficult partly because exclusion criteria for selection of reference data are quite rigid and partly due to the compartmentalization considerations regarding age and sex of the reference individuals. Moreover, construction of Biological Reference Curve (BRC) of urea is imperative to highlight the partitioning requirements. Materials and Methods: This a priori study examines the data collected by measuring serum urea of 3202 age and sex matched individuals, aged between 1 and 80 years, by a kinetic UV Urease/GLDH method on a Roche Cobas 6000 auto-analyzer. Results: Mann-Whitney U test of the reference data confirmed the partitioning requirement by both age and sex. Further statistical analysis revealed the incompatibility of the data for a proposed parametric model. Hence the data was non-parametrically analysed. BRI was found to be identical for both sexes till the 2nd decade, and the BRI for males increased progressively 6th decade onwards. Four non-parametric models were postulated for construction of BRC: Gaussian kernel, double kernel, local mean and local constant, of which the last one generated the best-fitting curves. Conclusion: Clinical decision making should become easier and diagnostic implications of renal function tests should become more meaningful if this BRI is followed and the BRC is used as a desktop tool in conjunction with similar data for serum creatinine.

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

    PubMed Central

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

    2014-01-01

    The aims of this study were to investigate the most effective combination of physical forces from laser, electroporation, and reverse iontophoresis for noninvasive transdermal extraction of uric acid, and to develop a highly sensitive uric acid biosensor (UAB) for quantifying the uric acid extracted. It is believed that the combination of these physical forces has additional benefits for extraction of molecules other than uric acid from human skin. A diffusion cell with porcine skin was used to investigate the most effective combination of these physical forces. UABs coated with ZnO2 nanoparticles and constructed in an array configuration were developed in this study. The results showed that a combination of laser (0.7 W), electroporation (100 V/cm2), and reverse iontophoresis (0.5 mA/cm2) was the most effective and significantly enhanced transdermal extraction of uric acid. A custom-designed UAB coated with ZnO2 nanoparticles and constructed in a 1×3 array configuration (UAB-1×3-ZnO2) demonstrated enough sensitivity (9.4 μA/mM) for quantifying uric acid extracted by the combined physical forces of laser, electroporation, and RI. A good linear relationship (R2=0.894) was demonstrated to exist between the concentration of uric acid (0.2–0.8 mM) inside the diffusion cell and the current response of the UAB-1×3-ZnO2. In conclusion, a new approach to noninvasive transdermal extraction and quantification of uric acid has been established. PMID:25061289

  3. Uric acid promotes left ventricular diastolic dysfunction in mice fed a Western diet.

    PubMed

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

    2015-03-01

    The rising obesity rates parallel increased consumption of a Western diet, high in fat and fructose, which is associated with increased uric acid. Population-based data support that elevated serum uric acids are associated with left ventricular hypertrophy and diastolic dysfunction. However, the mechanism by which excess uric acid promotes these maladaptive cardiac effects has not been explored. In assessing the role of Western diet-induced increases in uric acid, we hypothesized that reductions in uric acid would prevent Western diet-induced development of cardiomyocyte hypertrophy, cardiac stiffness, and impaired diastolic relaxation by reducing growth and profibrotic signaling pathways. Four-weeks-old C57BL6/J male mice were fed excess fat (46%) and fructose (17.5%) with or without allopurinol (125 mg/L), a xanthine oxidase inhibitor, for 16 weeks. The Western diet-induced increases in serum uric acid along with increases in cardiac tissue xanthine oxidase activity temporally related to increases in body weight, fat mass, and insulin resistance without changes in blood pressure. The Western diet induced cardiomyocte hypertrophy, myocardial oxidative stress, interstitial fibrosis, and impaired diastolic relaxation. Further, the Western diet enhanced activation of the S6 kinase-1 growth pathway and the profibrotic transforming growth factor-β1/Smad2/3 signaling pathway and macrophage proinflammatory polarization. All results improved with allopurinol treatment, which lowered cardiac xanthine oxidase as well as serum uric acid levels. These findings support the notion that increased production of uric acid with intake of a Western diet promotes cardiomyocyte hypertrophy, inflammation, and oxidative stress that lead to myocardial fibrosis and associated impaired diastolic relaxation.

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

    PubMed Central

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

    2013-01-01

    Background In firefly light organs, reflector layer is a specialized tissue which is believed to play a key role for increasing the bioluminescence intensity through reflection. However, the nature of this unique tissue remains elusive. In this report, we investigated the role, fine structure and nature of the reflector layer in the light organ of adult Luciola cerata. Principal Findings Our results indicated that the reflector layer is capable of reflecting bioluminescence, and contains abundant uric acid. Electron microscopy (EM) demonstrated that the cytosol of the reflector layer's cells is filled with densely packed spherical granules, which should be the uric acid granules. These granules are highly regular in size (∼700 nm in diameter), and exhibit a radial internal structure. X-ray diffraction (XRD) analyses revealed that an intense single peak pattern with a d-spacing value of 0.320 nm is specifically detected in the light organ, and is highly similar to the diffraction peak pattern and d-spacing value of needle-formed crystals of monosodium urate monohydrate. However, the molar ratio evaluation of uric acid to various cations (K+, Na+, Ca2+ and Mg2+) in the light organ deduced that only a few uric acid molecules were in the form of urate salts. Thus, non-salt uric acid should be the source of the diffraction signal detected in the light organ. Conclusions In the light organ, the intense single peak diffraction signal might come from a unique needle-like uric acid form, which is different from other known structures of non-salt uric acid form. The finding of a radial structure in the granules of reflector layer implies that the spherical uric acid granules might be formed by the radial arrangement of needle-formed packing matter. PMID:23441187

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

    PubMed

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

    2014-01-01

    The aims of this study were to investigate the most effective combination of physical forces from laser, electroporation, and reverse iontophoresis for noninvasive transdermal extraction of uric acid, and to develop a highly sensitive uric acid biosensor (UAB) for quantifying the uric acid extracted. It is believed that the combination of these physical forces has additional benefits for extraction of molecules other than uric acid from human skin. A diffusion cell with porcine skin was used to investigate the most effective combination of these physical forces. UABs coated with ZnO₂ nanoparticles and constructed in an array configuration were developed in this study. The results showed that a combination of laser (0.7 W), electroporation (100 V/cm(2)), and reverse iontophoresis (0.5 mA/cm(2)) was the most effective and significantly enhanced transdermal extraction of uric acid. A custom-designed UAB coated with ZnO₂ nanoparticles and constructed in a 1×3 array configuration (UAB-1×3-ZnO₂) demonstrated enough sensitivity (9.4 μA/mM) for quantifying uric acid extracted by the combined physical forces of laser, electroporation, and RI. A good linear relationship (R(2)=0.894) was demonstrated to exist between the concentration of uric acid (0.2-0.8 mM) inside the diffusion cell and the current response of the UAB-1×3-ZnO₂. In conclusion, a new approach to noninvasive transdermal extraction and quantification of uric acid has been established.

  6. Uric Acid Level and Erectile Dysfunction In Patients With Coronary Artery Disease

    PubMed Central

    Solak, Yalcin; Akilli, Hakan; Kayrak, Mehmet; Aribas, Alpay; Gaipov, Abduzhappar; Turk, Suleyman; Perez-Pozo, Santos E.; Covic, Adrian; McFann, Kim; Johnson, Richard J.; Kanbay, Mehmet

    2013-01-01

    Introduction Erectile dysfunction (ED) is a frequent complaint of elderly subjects, and is closely associated with endothelial dysfunction and cardiovascular disease. Uric acid is also associated with endothelial dysfunction, oxidative stress and cardiovascular disease, raising the hypothesis that an increased serum uric acid might predict erectile dysfunction in patients who are at risk for coronary artery disease. Aim To evaluate the association of serum uric acid levels with presence and severity of ED in patients presenting with chest pain of presumed cardiac origin. Methods This is a cross-sectional study of 312 adult male patients with suspected coronary artery disease who underwent exercise stress test (EST) for workup of chest pain and completed a sexual health inventory for men (SHIM) survey form to determine the presence and severity of ED. Routine serum biochemistry (and uric acid levels) were measured. Logistic regression analysis was used to assess risk factors for ED. Main Outcome Measures The short version of the international index of erectile function (IIEF-5) questionnaire diagnosed ED (cutoff score ≤21). Serum Uric acid levels were determined. Patients with chest pain of suspected cardiac origin underwent an exercise stress test. Results 149 of 312 (47.7%) male subjects had ED by survey criteria. Patients with ED were older and had more frequent CAD, hypertension, diabetes, and impaired renal function, and also had significantly higher levels of uric acid, fibrinogen, glucose, CRP, triglycerides compared with patients without ED. Uric acid levels were associated with ED by univariate analysis (OR = 1.36, p = 0.002); however, this association was not observed in multivariate analysis adjusted for eGFR. Conclusion Subjects presenting with chest pain of presumed cardiac origin are more likely to have ED if they have elevated uric acid levels. PMID:24433559

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

    SciTech Connect

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

    2014-11-15

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

  8. a Search for Interstellar Urea with Carma

    NASA Astrophysics Data System (ADS)

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

    2009-06-01

    Urea, a molecule discovered in human urine by H. M Rouelle in 1773, also plays a significant role in prebiotic chemistry. Previous BIMA observations have suggested that interstellar urea [(NH_2)_2CO] is a compact hot core molecule such as the other large molecules methyl formate and acetic acid (2008, 63rd OSU Symposium On Molecular Spectroscopy, RF11). We have conducted an extensive search for urea toward the high mass hot molecular core Sgr B2(N-LMH) using the CARMA array. The resolution at 1 mm enables favorable coupling of source size and synthesized beam size, which was found to be essential for flux measurements and detection limits of weak signals. The 2.5^''×2^'' synthesized beam of CARMA significantly resolves out the extended emission and reveals the weak lines that were previously blended with nearby transitions. Our analysis indicates that these lines are likely to be urea since they are now less contaminated, the resulting observed line frequencies are coincident with a set of overlapping connecting urea lines, and the observed line intensities are consistent with expected line strengths of urea.

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

    PubMed Central

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

    2014-01-01

    Hyperuricemia is a common finding in chronic kidney disease due to decreased uric acid clearance. The role of uric acid as a risk factor for chronic kidney disease has been largely debated, and recent studies suggested a role of uric acid in the causation and progression of kidney fibrosis, a final common pathway in chronic kidney disease. Uric acid and xanthine oxidase may contribute to kidney fibrosis mainly by inducing inflammation, endothelial dysfunction, oxidative stress, and activation of the renin-angiotensin system. Besides, hyperuricemia induces alterations in renal hemodynamics via afferent arteriolopathy and contributes to the onset and progression of kidney fibrosis. Xanthine oxidase inhibitors may prevent kidney damage via lowering uric acid and/or inhibiting xanthine oxidase. However, there is still no sufficient evidence from interventional clinical researches supporting the causal relationship between uric acid and kidney fibrosis. The effect and role of xanthine oxidase inhibitors in preventing kidney fibrosis and chronic kidney disease progression must be further explored by performing future large scale clinical trials. PMID:24877124

  10. Activity and Stability of Biofilm Uricase of Lactobacillus plantarum for Uric Acid Biosensor

    NASA Astrophysics Data System (ADS)

    Iswantini, Dyah; Rachmatia, Rescy; Diana, Novita Rose; Nurhidayat, Novik; Akhiruddin; Saprudin, Deden

    2016-01-01

    Research of uric acid biosensor used a Lactobacillus plantarum was successfully conducted. Lactobacillus plantarum could produce uricase that could be used as uric acid biosensor. Therefore, lifetime of bacteria were quite short that caused the bacteria could not detect uric acid for a long time. To avoid this problem, development of biofilm for uric acid biosensor is important. Biofilms is a structured community of bacterial cells, stick together and are able to maintain a bacteria in an extreme environments. The purpose of present study was to determine and compare the activity of uricase produced by L. plantarum, deposited whithin biofilm and planktonic bacteria on glassy carbon electrode (GCEb & GCE), also to determine the stability of biofilm. The optimization process was conducted by using temperature, pH, and substrate concentration as the parameters. It showed that the activity of uricase within biofilm was able to increase the oxidation current. GCEb and GCE yielded the oxidation current in the amount of 47.24 μA and 23.04 μA, respectively, under the same condition. Results indicated that the optimum condition for uric acid biosensor using biofilm were pH 10, temperature of 40 oC, and uric acid concentration of 5 mM. The stability of GCEb decreased after 10 hours used, with decreasing percentage over 86.33%. This low stability probably caused by the unprotected active site of the enzyme that the enzyme is easier to experience the denaturation.

  11. 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.

  12. Uric acid levels predict future blood pressure and new onset hypertension in the general Japanese population.

    PubMed

    Takase, H; Kimura, G; Dohi, Y

    2014-09-01

    We tested the hypothesis that uric acid levels predict new-onset hypertension in the Japanese general population. Normotensive individuals who visited our hospital for a yearly health checkup (n=8157, men=61.0% and age=50.7±12.2 years) were enrolled in the present study. After baseline evaluation, participants were followed up for a median of 48.3 months (range 4.9-101.0 months), with the endpoint being the development of hypertension, defined as systolic blood pressure (BP) > or = 140 mm Hg, diastolic BP > or = 90 mm Hg or the use of antihypertensive medication. The impact of uric acid and other cardiovascular risk factors at baseline on future BP and development of hypertension was assessed. During follow-up, 19.0% of women (n=605) and 29.5% of men (n=1469) participants developed hypertension. Incident hypertension was increased across the quartiles for baseline uric acid levels (P<0.0001), and multivariate Cox proportional hazards analysis revealed a significant and independent association between the uric acid level and the onset of hypertension in both men and women participants (P<0.05). Furthermore, uric acid was independently and positively correlated with future BP (P<0.05). Thus, uric acid is an independent predictor of new-onset hypertension in both women and men.

  13. Serum Uric Acid and Hypertension in Adults: a Paradoxical Relationship in Type 1 Diabetes

    PubMed Central

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

    2014-01-01

    Adults with type 1 diabetes have lower serum uric acid levels compared to non-diabetic adults. Little is known about the relationship between serum uric acid and blood pressure in type 1 diabetes and whether it differs from the positive relationship found in non-diabetic adults. We assessed the cross-sectional and longitudinal relationships over 6-years between serum uric acid and blood pressure in adults with (35±9 years, n=393) and without (38±9 years n=685) T1D in the Coronary Artery Calcification in Type 1 Diabetes study. In non-diabetic adults, serum uric acid was associated with systolic blood pressure in multivariable-models adjusted for cardiovascular risk-factors. In adults with type 1 diabetes, a negative association was observed between serum uric acid and systolic blood pressure after multivariable-adjustments. A positive association was observed between serum uric acid and systolic blood pressure in non-diabetic adults. In contrast, an inverse relationship was demonstrated after multivariable-adjustments in type 1 diabetes. PMID:24667019

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

    PubMed

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

    2014-04-01

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

  15. Effect of canagliflozin on serum uric acid in patients with type 2 diabetes mellitus.

    PubMed

    Davies, M J; Trujillo, A; Vijapurkar, U; Damaraju, C V; Meininger, G

    2015-04-01

    Hyperuricaemia is associated with an increased risk of gout, kidney stones and cardiovascular disease. The present post hoc analysis of pooled data from four placebo-controlled phase III studies assessed the effect of canagliflozin, a sodium-glucose co-transporter 2 inhibitor, on serum uric acid levels in patients with type 2 diabetes mellitus (T2DM) and in a subset of patients with hyperuricaemia [defined as baseline serum uric acid ≥475 µmol/l (∼8 mg/dl)]. At week 26, canagliflozin 100 and 300 mg were associated with a ∼13% reduction in serum uric acid compared with placebo. In the subset of patients with hyperuricaemia, placebo-subtracted percent reductions in serum uric acid were similar to those in the overall cohort. More patients in the hyperuricaemic group achieved a serum uric acid level of <360 µmol/l (∼6 mg/dl) with both canagliflozin 100 mg (23.5%) and 300 mg (32.4%) compared with placebo (3.1%). Incidences of gout and kidney stones were low and similar across groups. In conclusion, canagliflozin treatment decreased serum uric acid in patients with T2DM, including those with baseline hyperuricaemia.

  16. Genotype-based changes in serum uric acid affect blood pressure

    PubMed Central

    Parsa, Afshin; Brown, Eric; Weir, Matthew R.; Fink, Jeffrey C.; Shuldiner, Alan R.; Mitchell, Braxton D.; McArdle, Patrick F.

    2013-01-01

    Elevated serum levels of uric acid consistently correlate with hypertension, but the directionality of the association remains debated. To help define this relationship, we used a controlled setting within a homogeneous Amish community and the Mendelian randomization of a nonsynonymous coding single-nucleotide polymorphism, rs16890979 (Val253Ile), in the SLC2A9 gene. This gene expresses the GLUT9 transporter that also transports uric acid and is associated with lower serum uric acid levels. We studied the unconfounded association between genotype and blood pressure in 516 Amish adults, each placed for 6 days on standardized diets, first with high sodium, followed by low sodium, with an intervening washout period. Blood pressure, measured using 24-h ambulatory monitoring, during both diet periods was used as the primary outcome. All participants were free of diuretic or other antihypertensive medications and the relationships between GLUT9 genotype and both serum uric acid and blood pressure were assessed. Each copy of the GLUT9 minor Ile allele was found to confer a significant 0.44 mg/dl reduction in serum uric acid and was associated with a significant mean decrease in the systolic blood pressure of 2.2 and 1.5 mm Hg on the high- and low-sodium diet, respectively. Thus, a Mendelian randomization analysis using variants in the GLUT9 gene indicates that a decrease in serum uric acid has a causal effect of lowering blood pressure. PMID:22189840

  17. 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.; Spector, June; Fadrowski, Jeffrey; Jaar, Bernard G.; Steuerwald, Amy J.; 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.

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

    PubMed Central

    West, Caroline E.; Rhodes, Blaine N.

    2014-01-01

    A viable, quick, and reliable method for determining urinary creatinine by liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and used to evaluate spot urine samples collected for the Washington Environmental Biomonitoring Survey (WEBS): part of the Washington State Department of Health, Public Health Laboratories (PHL). 50 µL of urine was mixed with a 1 : 1 acetonitrile/water solution containing deuterated creatinine as the internal standard and then analyzed by LC/MS/MS. Utilizing electrospray ionization (ESI) in positive mode, the transition ions for creatinine and creatinine-d3 were determined to be 114.0 to 44.1 (quantifier), 114.0 to 86.1 (qualifier), and 117.0 to 47.1 (creatinine-d3). The retention time for creatinine was 0.85 minutes. The linear calibration range was 20–4000 mg/L, with a limit of detection at 1.77 mg/L and a limit of quantitation at 5.91 mg/L. LC/MS/MS and the colorimetric Jaffé reaction were associated significantly (Pearson r = 0.9898 and R2 = 0.9797, ρ ≤ 0.0001). The LC/MS/MS method developed at the PHL to determine creatinine in the spot urine samples had shorter retention times, and was more sensitive, reliable, reproducible, and safer than other LC/MS/MS or commercial methods such as the Jaffé reaction or modified versions thereof. PMID:25614740

  19. 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

  20. Association of serum uric acid level with mortality and morbidity of patients with acute ST-elevation myocardial infarction

    PubMed Central

    Hajizadeh, Reza; Ghaffari, Samad; Salehi, Rezvanieh; Mazani, Sarvin; Aghavali, Sharmin

    2016-01-01

    Introduction: Investigating the clinical impact of serum uric acid (UA) and its lowering agents on the complications and mortality of acute ST-elevation myocardial infarction (STEMI) can open a new era in STEMI treatment. The aim of this study was to evaluate the effect of on admission serum UA level on the mortality and morbidity of patients admitted with STEMI. Methods: A number of 608 patients with STEMI were enrolled in this study from December 21, 2012 until February 19, 2014. Patients were followed for 20 months. Male to female ratio was 2.53, and the mean age of patients was 62.6±13.4. The relationship between the level of UA and patients’ mortality and morbidity, left ventricular ejection fraction (LVEF), atrial and ventricular arrhythmia was analyzed. Results: Patients with high serum UA level had higher Killip class after STEMI (P=0.001). Mean LVEF was measured to be 39.5±9.6 in normal UA group and 34.6±11.6 in high UA group (P=0.001). In comparison with normal UA group, high UA group had significantly higher cTnI (2.68±0.09 vs 4.09±0.42, respectively, P=0.001), increased blood pressure (P=0.009), and higher atrial fibrillation (AF) occurrence (P=0.03), but no association was seen between ventricular tachycardia and serum UA level. Short term and midterm mortality were not different in two groups (P=0.44 and 0.31, respectively). Conclusion: In the current study, high serum UA level in patients with acute myocardial infarction (MI) was not associated with higher in-hospital or midterm mortality, but it was associated with lower LVEF, higher Killip class, elevated cTnI, creatinine, triglyceride, and higher AF. PMID:27489597

  1. Association of serum uric acid with incident atrial fibrillation (from the Atherosclerosis Risk in Communities [ARIC] study).

    PubMed

    Tamariz, Leonardo; Agarwal, Sunil; Soliman, Elsayed Z; Chamberlain, Alanna M; Prineas, Ronald; Folsom, Aaron R; Ambrose, Marietta; Alonso, Alvaro

    2011-11-01

    Atrial fibrillation (AF) is one of the most common arrhythmias seen in clinical practice. Current evidence suggests that serum uric acid (SUA) could be a marker of oxidative damage, a factor reported as a part of the mechanisms of AF. The purpose of the present study was to evaluate whether SUA predicted AF in the Atherosclerosis Risk In Communities (ARIC) study. The present analysis included 15,382 AF-free black and white men and women, aged 45 to 64 years, from the ARIC study, a population-based prospective cohort in the United States. SUA was determined using the uricase-peroxidase method at baseline. The primary outcome was the incidence of AF, defined as the occurrence of AF detected using hospital discharge codes, scheduled study electrocardiograms, and/or death certificates during the follow-up period (1987 to 2004). We identified 1,085 cases of incident AF. In Cox proportional hazards models adjusted for age, gender, race, center, education, body mass index, serum glucose, systolic and diastolic blood pressure, low-density lipoprotein cholesterol, alcohol use, prevalent coronary heart disease and heart failure, serum creatinine, diuretics, and P-wave duration on the electrocardiogram (as a measure of left atrial size) at baseline, the hazard ratio of AF associated with a SD increment in SUA was 1.16 (95% confidence interval 1.06 to 1.26). The association of SUA with AF risk differed by race and gender (p for interaction <0.01). In conclusion, elevated SUA is associated with a greater risk of AF, particularly among blacks and women. Additional studies should replicate this association and explore potential mechanisms.

  2. [Sensitivity and specificity of blood amylase, amylase and creatinine clearance ratio and urinary amylase/urinary creatinine ratio in the diagnosis of acute pancreatitis].

    PubMed

    Ligny, G; Meunier, J C; Hayard, P; Ligny, C; Van Cauter, J

    1987-12-01

    The sensitivity and specificity of amylasemia, the ratios of amylase/creatinine clearance and amylasuria/creatininuria were determined in four groups of patients: a control group (n = 43), patients with acute pancreatitis detected on computed tomography (n = 30, 25 cases of alcoholic pancreatitis), patients with an acute surgical abdomen without pancreatitis (n = 25), and patients with renal failure (n = 20). Sensitivity was defined for the acute pancreatitis group and specificity for the other groups. When amylasemia was greater than 20 UI/dl and the amylasuria/creatininuria ratio greater than 100, sensitivity was 98 per cent. The specificity of these two results in patients with an acute surgical abdomen was 98 per cent. When the ratio amylase/creatinine clearance ratio was greater than 4 sensitivity was 73 per cent and specificity in patients with acute surgical abdomen was 75 per cent. These two values were lower than those of the two preceding tests (p less than 0.01). Sensitivity of the association of an amylasemia greater than 13 UI/dl (m + 2SD) with a clearance ratio greater than 4 was 73 per cent. The amylase/creatinine clearance ratio did not seem to be reliable since its change was delayed with respect to the increase of amylasemia and amylasuria. This ratio has a poor specificity as it increased when the clearance of creatinine decreased in the group with an acute surgical abdomen associated with functional or organic renal failure. In these two groups, the correlation between the amylase/creatinine clearance ratio and creatininemia was significant. This suggested that the clearance of creatinine fell more rapidly than the clearance of amylase as renal failure increased.

  3. Limitation of amylase creatinine clearance ratio as a diagnostic test for postoperative pancreatitis.

    PubMed

    Wapnick, S; Evans, M I; Hadas, N; Grosberg, S J

    1980-05-01

    The mean +/- S.E.M. ratio of amylase to creatinine clearance significantly increased at 24 hours after operations on the stomach and gallbladder but not after operations at sites remote from the abdominal cavity. Clinically, the elevated amylase to creatinine clearance ratio was not accompanied by pancreatitis. In dogs, surgical handling of the pancreas alone caused a significant increase in this measurement. The amylase to creatinine clearance ratio is not likely to be helpful in predicting the rare, but serious, postoperative complication of pancreatitis.

  4. Is Uric Acid a Missing Link between Previous Gestational Diabetes Mellitus and the Development of Type 2 Diabetes at a Later Time of Life?

    PubMed Central

    Fronczyk, Aneta; Safranow, Krzysztof; Majkowska, Lilianna

    2016-01-01

    Introduction A high level of uric acid (UA) is a strong, independent risk factor for type 2 diabetes mellitus. The relationship between UA levels and the development of type 2 diabetes in women with previous gestational diabetes mellitus (pGDM) remains unclear. The aim of study was to evaluate the UA levels in pGDM women in relation to their current nutritional status and carbohydrate metabolism. Material and Methods 199 women with pGDM diagnoses based on oral glucose tolerance tests (OGTTs) 5–12 years previously and a control group of 50 women without pGDM. The assessment included anthropometric parameters, body composition (Tanita SC-330S), current OGTT, insulin resistance index (HOMA-IR), β-cell function (HOMA-%B), HbA1c, lipids, and uric acid. Results No differences between groups were found in terms of age, time from the index pregnancy, anthropometric parameters, lipids or creatinine levels. The incidences of overweight and obesity were similar. Carbohydrate abnormalities were more frequent in the pGDM group than the control group (43.2% vs 12.0% p<0.001). The women with pGDM had significantly higher fasting glucose, HbA1c, glucose and insulin levels in the OGTTs, but similar HOMA-IR values. Their UA levels were significantly higher (258±58 vs 230±50 μmol/L, p<0.005) and correlated with BMI and the severity of carbohydrate disorders. The normal weight and normoglycemic pGDM women also demonstrated higher UA levels than a similar control subgroup (232±48 vs 208±48 μmol/L, p<0.05). Multivariate analysis revealed significant correlations of UA level with BMI (β = 0.38, 95% CI 0.25–0.51, p<0.0001), creatinine level (β = 0.23, 95% CI 0.11–0.35, p<0.0005), triglycerides (β = 0.20, 95% CI 0.07–0.33, p<0.005) and family history of diabetes (β = 0.13, 95% CI 0.01–0.25, p<0.05). In logistic regression analysis, the association between higher UA level (defined as value ≥297 μmol/L) and presence of any carbohydrate metabolism disorder (IFG, IGT or

  5. 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

  6. Does high serum uric acid level cause aspirin resistance?

    PubMed

    Yildiz, Bekir S; Ozkan, Emel; Esin, Fatma; Alihanoglu, Yusuf I; Ozkan, Hayrettin; Bilgin, Murat; Kilic, Ismail D; Ergin, Ahmet; Kaftan, Havane A; Evrengul, Harun

    2016-06-01

    In patients with coronary artery disease (CAD), though aspirin inhibits platelet activation and reduces atherothrombotic complications, it does not always sufficiently inhibit platelet function, thereby causing a clinical situation known as aspirin resistance. As hyperuricemia activates platelet turnover, aspirin resistance may be specifically induced by increased serum uric acid (SUA) levels. In this study, we thus investigated the association between SUA level and aspirin resistance in patients with CAD. We analyzed 245 consecutive patients with stable angina pectoris (SAP) who in coronary angiography showed more than 50% occlusion in a major coronary artery. According to aspirin resistance, two groups were formed: the aspirin resistance group (Group 1) and the aspirin-sensitive group (Group 2). Compared with those of Group 2, patients with aspirin resistance exhibited significantly higher white blood cell counts, neutrophil counts, neutrophil-to-lymphocyte ratios, SUA levels, high-sensitivity C-reactive protein levels, and fasting blood glucose levels. After multivariate analysis, a high level of SUA emerged as an independent predictor of aspirin resistance. The receiver-operating characteristic analysis provided a cutoff value of 6.45 mg/dl for SUA to predict aspirin resistance with 79% sensitivity and 65% specificity. Hyperuricemia may cause aspirin resistance in patients with CAD and high SUA levels may indicate aspirin-resistant patients. Such levels should thus recommend avoiding heart attack and stroke by adjusting aspirin dosage. PMID:26656902

  7. 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.

  8. 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 ...

  9. 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...

  10. Amylase-creatinine clearance ratios and serum amylase isoenzymes in moderate renal insufficiency.

    PubMed

    Banks, P A; Sidi, S; Gelman, M L; Lee, K H; Warshaw, A L

    1979-12-01

    Both the amylase-creatinine clearance ratio (normal 1.55%) and proportion of pancreatic isoamylase in serum (normal 41.0%) increase in acute pancreatitis, and are therefore useful measurements to support that diagnosis. Whether renal insufficiency interferes with the accuracy and specificity of these tests has been debated. Our study indicates that even moderate renal insufficiency (creatinine clearance 30.5 ml/minute) raises the amylase-creatinine clearance ratio (3.23%) close enough to values characteristic of acute pancreatitis (4.41%) to cause potential diagnostic confusion. The fraction of pancreatic isoamylase in serum is also increased (69.9%), but not to the levels of acute pancreatitis (91.0%). We therefore caution against the use of the amylase-creatinine clearance ratio for the diagnosis of acute pancreatitis in patients with moderate renal insufficiency.

  11. Sensitivity of the amylase-creatinine clearance ratio in acute pancreatitis.

    PubMed

    Farrar, W H; Calkins, G

    1978-06-01

    An elevated amylase-creatinine clearance ratio has been established as being highly specific for the diagnosis of acute pancreatitis. In the present study, the sensitivity of this test was compared to that of the serum amylase and the one-hour urinary amylase test in 29 patients with acute pancreatitis. Abnormal elevations of the amylase-creatinine clearance ratio were found less frequently than abnormal elevations of the serum and one-hour urinary amylases. Moreover, abnormal elevations of the amylase-creatinine clearance ratio showed less deviation from normal and values returned to normal sooner than those of the serum and one-hour urinary amylases. When compared to the serum amylase and the one-hour urinary amylase tests, the amylase-creatinine clearance ratio is a relatively insensitive test in patients with acute pancreatitis.

  12. A practical approach to using spot urine protein/creatinine ratios for assessing proteinuria in pregnancy

    PubMed Central

    Marnoch, Catherine A; Larson, Lucia; Weitzen, Sherry; Phipps, Maureen G; Sung, C James; Powrie, Raymond O

    2008-01-01

    Objective: The aim of this study is to assess the diagnostic accuracy of the spot urine protein/creatinine ratio compared with the 24-hour urine protein in pregnancy. Study Design: In this prospective cohort study of inpatient pregnant women, the protein/creatinine ratio and dipstick protein were assessed from a single urine sample collected at the start of the 24-hour urine. Both tests were compared with the 24-hour urine protein for correlation and test characteristics. Results: In the 196 specimens analysed, we found a strong correlation between the spot urine protein/creatinine ratio and 24-hour urine protein (r 2 = 0.78, P < 0.01). A protein/creatinine ratio <0.1 ruled out significant proteinuria (≥300 mg/day) with sensitivity and negative predictive value 100%. A protein/creatinine ratio ≥0.4 detected significant proteinuria (specificity and positive predictive value of 100%). A protein/creatinine ratio ≥4.6 had a specificity and positive predictive value of 100% for detecting severe proteinuria (≥5000 mg/day). Urine dipsticks correlated poorly with the 24-hour urine protein (r 2 = 0.40, P = 0.826). Nineteen percent of dipsticks reading nil or trace were false-negative results. Conclusion: The spot urine protein/creatinine ratio correlated well with the 24-hour urine protein and performed better than the urine dipsticks. Significant proteinuria in pregnancy was excluded if the protein/creatinine ratio was <0.1 and identified when it was ≥0.4. PMID:27630741

  13. [New topics regarding equations for GFR estimation based on serum creatinine and cystatin C].

    PubMed

    Horio, Masaru

    2014-02-01

    Japanese GFR equations and CKD-EPI equations based on standardized serum creatinine and standardized cystatin C are recommended in recent Japanese CKD guides and KDIGO guidelines for CKD management, respectively. CKD-EPIcreat overestimates GFR in Japanese subjects, probably due to the difference in muscle mass between Japanese and Caucasians. Unlike CKD-EPIcreat, CKD-EPIcys performs well in Japanese subjects, indicating the advantages of using cystatin C as a GFR marker. KDIGO guidelines suggest measuring eGFRcys in adults with eGFRcreat of 45-59 ml/min/1.73 m2 who do not have markers of kidney damage if confirmation of CKD is required. Creatinine is excreted by glomerular filtration, but also secreted by the tubules. Alteration of the tubular secretion of creatinine may influence the performance of GFR equations based on serum creatinine. Multivariate analysis showed that GFR and serum albumin levels were independent parameters affecting the fractional excretion of creatinine (FE-Cr). Alteration of FE-Cr according to the serum albumin levels may be one of the reasons for the bias of GFR equations based on serum creatinine. Low GFR is a risk factor for all-cause and cardiovascular mortality in a general population. However, the relationship between eGFR and the hazard risk of events is different depending on whether cystatin C or creatinine is used to calculate eGFR. The association between eGFRcys and the hazard risk is much stronger compared with eGFRcreat. Cystatin C may be a useful alternative to creatinine for detecting a high risk of complications in a general population and subjects with CKD.

  14. The value of the amylase/creatinine clearance ratio in the diagnosis of acute pancreatitis.

    PubMed

    Solomon, A R

    1978-01-01

    Acute pancreatitis usually confronts the clinician with a difficult diagnostic task. For years, the primary laboratory diagnostic tests were the serum and urine amylase and the serum lipase determinations. Recent studies have introduced the concept of the amylase/creatinine clearance ratio as a means of increasing the specificity of the laboratory diagnosis. This paper reviews the laboratory evaluation of acute pancreatitis with emphasis on the rationale, derivation, and specificity of the amylase/creatinine clearance ratio.

  15. 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 (4×40 mm(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 2.5-25 mg dL(-1) (r(2)=0.983), and the detection limit was 2.0 mg dL(-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.

  16. The Effects of Fructose Intake on Serum Uric Acid Vary among Controlled Dietary Trials1234

    PubMed Central

    Wang, D. David; Sievenpiper, John L.; de Souza, Russell J.; Chiavaroli, Laura; Ha, Vanessa; Cozma, Adrian I.; Mirrahimi, Arash; Yu, Matthew E.; Carleton, Amanda J.; Di Buono, Marco; Jenkins, Alexandra L.; Leiter, Lawrence A.; Wolever, Thomas M. S.; Beyene, Joseph; Kendall, Cyril W. C.; Jenkins, David J. A.

    2012-01-01

    Hyperuricemia is linked to gout and features of metabolic syndrome. There is concern that dietary fructose may increase uric acid concentrations. To assess the effects of fructose on serum uric acid concentrations in people with and without diabetes, we conducted a systematic review and meta-analysis of controlled feeding trials. We searched MEDLINE, EMBASE, and the Cochrane Library for relevant trials (through August 19, 2011). Analyses included all controlled feeding trials ≥7 d investigating the effect of fructose feeding on uric acid under isocaloric conditions, where fructose was isocalorically exchanged with other carbohydrate, or hypercaloric conditions, and where a control diet was supplemented with excess energy from fructose. Data were aggregated by the generic inverse variance method using random effects models and expressed as mean difference (MD) with 95% CI. Heterogeneity was assessed by the Q statistic and quantified by I2. A total of 21 trials in 425 participants met the eligibility criteria. Isocaloric exchange of fructose for other carbohydrate did not affect serum uric acid in diabetic and nondiabetic participants [MD = 0.56 μmol/L (95% CI: −6.62, 7.74)], with no evidence of inter-study heterogeneity. Hypercaloric supplementation of control diets with fructose (+35% excess energy) at extreme doses (213–219 g/d) significantly increased serum uric acid compared with the control diets alone in nondiabetic participants [MD = 31.0 mmol/L (95% CI: 15.4, 46.5)] with no evidence of heterogeneity. Confounding from excess energy cannot be ruled out in the hypercaloric trials. These analyses do not support a uric acid-increasing effect of isocaloric fructose intake in nondiabetic and diabetic participants. Hypercaloric fructose intake may, however, increase uric acid concentrations. The effect of the interaction of energy and fructose remains unclear. Larger, well-designed trials of fructose feeding at “real world” doses are needed. PMID:22457397

  17. 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 μmol L(-1), with a very low limit of detection of 1.0 μmol 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

  18. Effect of co-trimoxazole and sulfamethoxazole on serum creatinine in normal subjects.

    PubMed

    Roy, M T; First, M R; Myre, S A; Cacini, W

    1982-01-01

    Significant elevation of serum creatinine concentration and reduction in creatinine clearance have been reported following cotrimoxazole therapy in patients with normal and impaired renal function. Both components of co-trimoxazole, trimethoprim and sulfamethoxazole, have been proposed as the causative agent. Ten healthy male volunteers were treated for seven days with either sulfamethoxazole (5 subjects) or co-trimoxazole (5 subjects) in the usual recommended doses. After a one-week recovery period, the subjects were allocated to the alternate treatment regimen for another seven days. Cotrimoxazole caused a mean elevation in the serum creatinine concentration of 0.12 mg/dl over the base-line value (p less than 0.05). Sulfamethoxazole produced an insignificant fall in the serum creatinine level. The increase in the serum creatinine concentration induced by co-trimoxazole was reversed seven days after discontinuation of the drug. From this study, it can be concluded that either trimethoprim alone or an interaction between trimethoprim and sulfamethoxazole is responsible for the increase in serum creatinine observed following co-trimoxazole therapy and that sulfamethoxazole alone is not the causative agent. PMID:7071907

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

    PubMed

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

    1978-12-01

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

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

    PubMed Central

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

    2013-01-01

    Background Hypercalciuria is one of the most common causes of unexplained isolated hematuria. The diagnostic methods for hypercalciuria have not yet been standardized. The aim of this study was to assess whether random urinary calcium/creatinine ratio could be used as a screening tool for hypercalciuria in children with hematuria. Methods This prospective study included 264 children with primary hematuria for whom both random and 24 hr urinary evaluations were performed. Pearson correlation and ROC curve were used to assess the correlations. A multiple linear regression model was used to analyze effects of age, weight, height, body mass index, and body surface area on random urinary calcium/creatinine ratio. Results There was a moderately strong correlation between random urinary calcium/creatinine ratio and 24 hr urinary calcium excretion (r=0.584, P<0.001). The most appropriate cutoff value of random urinary calcium/creatinine ratio for the estimation of hypercalciuria was 0.075 mg/mg (sensitivity, 77.8%; specificity, 64.3%; area under the curve, 0.778). Body mass index and 24 hr urinary calcium excretion significantly affected random urinary calcium/creatinine ratio with a low coefficient of determination (r2=0.380, P<0.001). Conclusions Random urinary calcium/creatinine ratio is not suitable for screening hypercalciuria in children with hematuria. Twenty-four hour urinary analysis should be performed to diagnose hypercalciuria in children with hematuria. PMID:24205487

  1. Uric acid: a modulator of prostate cells and activin sensitivity.

    PubMed

    Sangkop, Febbie; Singh, Geeta; Rodrigues, Ely; Gold, Elspeth; Bahn, Andrew

    2016-03-01

    Elevated serum uric acid (SUA) or urate is associated with inflammation and gout. Recent evidence has linked urate to cancers, but little is known about urate effects in prostate cancer. Activins are inflammatory cytokines and negative growth regulators in the prostate. A hallmark of prostate cancer progression is activin insensitivity; however, mechanisms underlying this are unclear. We propose that elevated SUA is associated with prostate cancer counteracting the growth inhibitory effects of activins. The expression of activins A and B, urate transporter GLUT9 and tissue urate levels were examined in human prostate disease. Intracellular and secreted urate and GLUT9 expression were assessed in human prostate cancer cell lines. Furthermore, the effects of urate and probenecid, a known urate transport inhibitor, were determined in combination with activin A. Activin A expression was increased in low-grade prostate cancer, whereas activin B expression was reduced in high-grade prostate cancer. Intracellular urate levels decreased in all prostate pathologies, while GLUT9 expression decreased in benign prostatic hyperplasia, prostatitis and high-grade prostate cancer. Activin responsive LNCaP cells had higher intracellular and lower secreted urate levels than activin-insensitive PC3 cells. GLUT9 expression in prostate cancer cells was progressively lower than in prostate epithelial cells. Elevated extracellular urate was growth promoting in vitro, which was abolished by the gout medication probenecid, and it antagonized the growth inhibitory effects of activins. This study shows for the first time that a change in plasma or intracellular urate levels, possibly involving GLUT9 and a urate efflux transporter, has an impact on prostate cancer cell growth, and that lowering SUA levels in prostate cancer is likely to be therapeutically beneficial. PMID:26910779

  2. Relation between uric acid and metabolic syndrome in subjects with cardiometabolic risk

    PubMed Central

    da Silva, Hellen Abreu; Carraro, Júlia Cristina Cardoso; Bressan, Josefina; Hermsdorff, Helen Hermana Miranda

    2015-01-01

    Objective To identify possible relations between serum uric acid levels and metabolic syndrome and its components in a population with cardiometabolic risk. Methods This cross-sectional study included 80 subjects (46 women), with mean age of 48±16 years, seen at the Cardiovascular Health Program. Results The prevalence of hyperuricemia and metabolic syndrome was 6.3% and 47.1%, respectively. Uric acid level was significantly higher in individuals with metabolic syndrome (5.1±1.6mg/dL), as compared to those with no syndrome or with pre-syndrome (3.9±1.2 and 4.1±1.3mg/dL, respectively; p<0.05). The uric acid levels were significantly higher in men presenting abdominal obesity, and among women with abdominal obesity, lower HDL-c levels and higher blood pressure (p<0.05). Conclusion Uric acid concentrations were positively related to the occurrence of metabolic syndrome and its components, and there were differences between genders. Our results indicate serum uric acid as a potential biomarker for patients with cardiometabolic risk. PMID:26018145

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

    PubMed Central

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

    2014-01-01

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

  4. 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 Leão; Cunha, Mariana Botrel; Belo, Vanessa Almeida; dos Santos, José Eduardo Tanus; Mourão-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; p<−0.001). Conclusions: The increase in serum uric 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

  5. Maternal fructose drives placental uric acid production leading to adverse fetal outcomes

    PubMed Central

    Asghar, Zeenat A.; Thompson, Alysha; Chi, Maggie; Cusumano, Andrew; Scheaffer, Suzanne; Al-Hammadi, Noor; Saben, Jessica L.; Moley, Kelle H.

    2016-01-01

    Maternal metabolic diseases increase offspring risk for low birth weight and cardiometabolic diseases in adulthood. Excess fructose consumption may confer metabolic risks for both women and their offspring. However, the direct consequences of fructose intake per se are unknown. We assessed the impact of a maternal high-fructose diet on the fetal-placental unit in mice in the absence of metabolic syndrome and determined the association between maternal serum fructose and placental uric acid levels in humans. In mice, maternal fructose consumption led to placental inefficiency, fetal growth restriction, elevated fetal serum glucose and triglyceride levels. In the placenta, fructose induced de novo uric acid synthesis by activating the activities of the enzymes AMP deaminase and xanthine oxidase. Moreover, the placentas had increased lipids and altered expression of genes that control oxidative stress. Treatment of mothers with the xanthine oxidase inhibitor allopurinol reduced placental uric acid levels, prevented placental inefficiency, and improved fetal weights and serum triglycerides. Finally, in 18 women delivering at term, maternal serum fructose levels significantly correlated with placental uric acid levels. These findings suggest that in mice, excess maternal fructose consumption impairs placental function via a xanthine oxidase/uric acid-dependent mechanism, and similar effects may occur in humans. PMID:27125896

  6. Inverse Association Between Serum Uric Acid Levels and Alzheimer's Disease Risk.

    PubMed

    Du, Na; Xu, Donghua; Hou, Xu; Song, Xuejia; Liu, Cancan; Chen, Ying; Wang, Yangang; Li, Xin

    2016-05-01

    The association between Alzheimer's disease and uric acid levels had gained great interest in recent years, but there was still lack of definite evidence. A systematic review and meta-analysis of relevant studies was performed to comprehensively estimate the association. Relevant studies published before October 26, 2014, were searched in PubMed, Embase, and China Biology Medicine (CBM) databases. Study-specific data were combined using random-effects or fixed-effects models of meta-analysis according to between-study heterogeneity. Twenty-four studies (21 case-control and 3 cohort studies) were finally included into the meta-analysis. Those 21 case-control studies included a total of 1128 cases of Alzheimer's disease and 2498 controls without Alzheimer's disease. Those 3 cohort studies included a total of 7327 participants. Meta-analysis showed that patients with Alzheimer's disease had lower levels of uric acid than healthy controls (weighted mean difference (WMD) = -0.77 mg/dl, 95% CI -2.28 to -0.36, P = 0.0002). High serum uric acid levels were significantly associated with decreased risk of Alzheimer's disease (risk ratio (RR) = 0.66, 95% CI 0.52-0.85, P = 0.001). There was low risk of publication bias in the meta-analysis. There is an inverse association between serum uric acid levels and Alzheimer's disease. High serum uric acid level is a protective factor of Alzheimer's disease.

  7. Low Serum Uric Acid Level Is a Risk Factor for Death in Incident Hemodialysis Patients

    PubMed Central

    Lee, S.M. Kurt; Lee, Andrew L.; Winters, Thomas J.; Tam, Emily; Jaleel, Mohammed; Stenvinkel, Peter; Johnson, Richard J.

    2009-01-01

    Background A reverse epidemiology of classic cardiovascular risk factors was observed in hemodialysis patients with a high comorbidity burden. We hypothesized that uric acid, a novel cardiovascular risk factor, also has an altered association with survival in these patients. Methods A retrospective study was conducted on 168 consecutive outpatient hemodialysis patients over a 6-year period. Serum uric acid, albumin levels and relevant laboratory information were recorded monthly. The disease severity was assessed using Comorbidity Index (CoI) scores. Patients were stratified into 3 groups according to their serum uric acid concentrations: group I was the lowest quintile, group II was the middle 3 quintiles and group III was the highest quintile. The risks of death were calculated utilizing a Cox regression model. Results Using group II as a reference group, the hazard ratio of group I was 2.23 [95% confidence interval (CI) 1.21–4.11, p = 0.01] and group III was 0.89 (95% CI 0.47–1.71, p = 0.74). The serum uric acid levels correlated inversely with CoI scores (r = −0.31, 95% CI −0.44 to −0.17, p < 0.0001) and positively with serum albumin levels (r = 0.35, 95% CI 0.21–0.48, p < 0.0001). Conclusion Low serum uric acid is a mortality risk factor in incident hemodialysis patients with a high comorbidity burden and hypoalbuminemia. PMID:18689987

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

    PubMed

    Kanchana, P; Sekar, C

    2014-09-01

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

  9. [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

  10. 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.

  11. [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.

  12. Stability of urea in solution and pharmaceutical preparations.

    PubMed

    Panyachariwat, Nattakan; Steckel, Hartwig

    2014-01-01

    The stability of urea in solution and pharmaceutical preparations was analyzed as a function of temperature (25°-60°C), pH (3.11-9.67), and initial urea concentration (2.5%-20%). This study was undertaken to (i) obtain more extensive, quantitative information relative to the degradation of urea in both aqueous and non-aqueous solutions and in pharmaceutical preparations, and (ii) test the effects of initial urea concentration, pH, buffer, and temperature values on urea degradation. The stability analysis shows that urea is more stable at the pH range of 4-8 and the stability of urea decreases by increase in temperature for all pH values. Within the experimental range of temperature and initial urea concentration values, the lowest urea degradation was found with lactate buffer pH 6.0. The urea decomposition rate in solution and pharmaceutical preparations shows the dependence of the initial urea concentrations. At higher initial urea concentrations, the rate of degradation is a decreasing function with time. This suggests that the reverse reaction is a factor in the degradation of concentrated urea solution. For non-aqueous solvents, isopropanol showed the best effort in retarding the decomposition of urea. Since the losses in urea is directly influenced by its stability at a given temperature and pH, the stability analysis of urea by the proposed model can be used to prevent the loss and optimize the operating condition for urea-containing pharmaceutical preparations.

  13. Is hyperuricemia a risk factor for arteriosclerosis? Uric acid and arteriosclerosis in apolipoprotein e-deficient mice.

    PubMed

    Wakuda, Hirokazu; Uchida, Shinya; Ikeda, Masahiko; Tabuchi, Masaki; Akahoshi, Yasumitsu; Shinozuka, Kazumasa; Yamada, Shizuo

    2014-01-01

    Although hyperlipidemia, high blood pressure, and diabetes increase the risk of arteriosclerosis, it is not clear whether hyperuricemia increases the risk of arteriosclerosis or not. We examined the effects of uric acid and curative drugs for hyperuricemia on atherosclerosis-susceptible C57BL/6J apolipoprotein E-deficient (apoE(-/-)) mice. Male apoE(-/-) mice (age: 6 weeks) were fed a normal diet (normal diet group) or a uric acid-enriched diet. Mice fed the uric acid-enriched diet were divided into three groups and administered a drinking vehicle (high uric acid diet group), allopurinol (20 mg·kg(-1)·d(-1)), or benzbromarone (20 mg·kg(-1)·d(-1)) for 10 weeks. Serum uric acid concentrations were higher in the high uric acid diet group than in the normal diet group, and concentrations in the allopurinol and benzbromarone groups were lower than in the high uric acid diet group. Serum total cholesterol and triglyceride levels were lower in the allopurinol group than in the high uric acid diet group. Oxidative stress was lower in the benzbromarone group than in the high uric acid diet group. Atherosclerotic lesion areas were smaller in the allopurinol and benzbromarone groups than in the high uric acid diet group. Thus, hyperuricemia may not be an independent risk factor for arteriosclerosis; however, the administration of allopurinol and benzbromarone prevented the development of atherosclerosis in apoE(-/-) mice fed a uric acid-enriched diet. The anti-atherosclerotic effect was in part due to lower total cholesterol and oxidative stress in the serum. Other possible mechanisms underlying this effect should be investigated.

  14. Accurate prediction of kidney allograft outcome based on creatinine course in the first 6 months posttransplant.

    PubMed

    Fritsche, L; Hoerstrup, J; Budde, K; Reinke, P; Neumayer, H-H; Frei, U; Schlaefer, A

    2005-03-01

    Most attempts to predict early kidney allograft loss are based on the patient and donor characteristics at baseline. We investigated how the early posttransplant creatinine course compares to baseline information in the prediction of kidney graft failure within the first 4 years after transplantation. Two approaches to create a prediction rule for early graft failure were evaluated. First, the whole data set was analysed using a decision-tree building software. The software, rpart, builds classification or regression models; the resulting models can be represented as binary trees. In the second approach, a Hill-Climbing algorithm was applied to define cut-off values for the median creatinine level and creatinine slope in the period between day 60 and 180 after transplantation. Of the 497 patients available for analysis, 52 (10.5%) experienced an early graft loss (graft loss within the first 4 years after transplantation). From the rpart algorithm, a single decision criterion emerged: Median creatinine value on days 60 to 180 higher than 3.1 mg/dL predicts early graft failure (accuracy 95.2% but sensitivity = 42.3%). In contrast, the Hill-Climbing algorithm delivered a cut-off of 1.8 mg/dL for the median creatinine level and a cut-off of 0.3 mg/dL per month for the creatinine slope (sensitivity = 69.5% and specificity 79.0%). Prediction rules based on median and slope of creatinine levels in the first half year after transplantation allow early identification of patients who are at risk of loosing their graft early after transplantation. These patients may benefit from therapeutic measures tailored for this high-risk setting. PMID:15848516

  15. 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.

  16. Genetic background of uric acid metabolism in a patient with severe chronic tophaceous gout.

    PubMed

    Petru, Lenka; Pavelcova, Katerina; Sebesta, Ivan; Stiburkova, Blanka

    2016-09-01

    Hyperuricemia depends on the balance of endogenous production and renal excretion of uric acid. Transporters for urate are located in the proximal tubule where uric acid is secreted and extensively reabsorbed: secretion is principally ensured by the highly variable ABCG2 gene. Enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT) plays a central role in purine metabolism and its deficiency is an X-linked inherited metabolic disorder associated with clinical manifestations of purine overproduction. Here we report the case of a middle-aged man with severe chronic tophaceous gout with a poor response to allopurinol and requiring repeated surgical intervention. We identified the causal mutations in the HPRT1 gene, variant c.481G>T (p.A161S), and in the crucial urate transporter ABCG2, a heterozygous variant c.421C>A (p.Q141K). This case shows the value of an analysis of the genetic background of serum uric acid. PMID:27288985

  17. Stable isotope ratios and uric acid preservation in termites belonging to three feeding habits in Thailand.

    PubMed

    Tayasu, I; Hyodo, F; Takematsu, Y; Sugimoto, A; Inoue, T; Kirtibutr, N; Abe, T

    2000-01-01

    Nitrogen and carbon stable isotope ratios and uric acid concentrations in termites sampled from a dry evergreen forest in Thailand, were determined across three kinds of feeding habits. Feeding habits of Microcerotermes crassus, which is an abundant wood-feeder, and Dicuspiditermes makhamensis, a common soil-feeding termite, were confirmed by isotopic signatures. Lichen feeding termites (Hospitalitermes birmanicus, H. bicolor and H. ataramensis) were characterized by low delta15N values, suggesting that they assimilated nitrogen deposited from the atmosphere. There was also a significant difference in uric acid concentrations between termites representing different feeding habits. No significant relationships were found between uric acid concentrations and delta15N or delta13C in Hospitalitermes. However, delta15N values were correlated with C/N ratios in H. birmanicus, except in one colony of H. ataramensis. delta13C values in both species were negatively correlated with C/N ratios.

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

    PubMed

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

    2015-02-01

    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.

  19. Synthesis and characterization of chitosan alkyl urea.

    PubMed

    Wang, Jing; Jiang, Ji-Zhou; Chen, Wei; Bai, Zheng-Wu

    2016-07-10

    Chitosan is a versatile material employed for various purposes in many fields including the development of chiral stationary phases for enantioseparation. Chitosan alkyl urea is a kind of intermediate used to prepare enantioseparation materials. In order to synthesize the intermediates, in the present work, a new way to prepare chitosan alkyl urea has been established: chitosan was first reacted with methyl chloroformate yielding N-methoxyformylated chitosan, which was then converted to chitosan alkyl urea through amine-ester exchange reaction. With a large excess of methyl chloroformate and primary amine of low stereohindrance, the amino group in chitosan could be almost completely converted to ureido group. The as-prepared chitosan alkyl urea derivatives were characterized by IR, (1)H NMR, (13)C NMR,(1)H-(1)H COSY and (1)H-(13)C HSQC NMR spectra. The chemical shifts of hydrogen and carbon atoms of glucose unit were assigned. It was found that the degree of substitution was obviously lower if cyclopropyl amine, aniline, tert-butyl amine and diethyl amine were used as reactants for the amine-ester exchange reaction. The reason was explained with the aid of theoretical calculations.

  20. Continuous Crystallization of Urea-Water Mixture

    NASA Astrophysics Data System (ADS)

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

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

  1. Aldehyde-containing urea-absorbing polysaccharides

    NASA Technical Reports Server (NTRS)

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

    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.

  2. 21 CFR 184.1923 - Urea.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... for its intended use. (c) In accordance with § 184.1(b)(1), the ingredient is used in food with no... recognized as safe as a direct human food ingredient is based upon the following current good manufacturing... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Urea. 184.1923 Section 184.1923 Food and...

  3. 21 CFR 184.1923 - Urea.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... for its intended use. (c) In accordance with § 184.1(b)(1), the ingredient is used in food with no... recognized as safe as a direct human food ingredient is based upon the following current good manufacturing... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Urea. 184.1923 Section 184.1923 Food and...

  4. 21 CFR 184.1923 - Urea.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... accordance with § 184.1(b)(1), the ingredient is used in food with no limitation other than current good... food ingredient is based upon the following current good manufacturing practice conditions of use: (1... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Urea. 184.1923 Section 184.1923 Food and...

  5. 21 CFR 184.1923 - Urea.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... for its intended use. (c) In accordance with § 184.1(b)(1), the ingredient is used in food with no... recognized as safe as a direct human food ingredient is based upon the following current good manufacturing... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Urea. 184.1923 Section 184.1923 Food and...

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

    PubMed

    Balakumar, Pitchai; Sharma, Ramica; Singh, Manjeet

    2008-01-01

    The study has been designed to investigate the effect of benfotiamine, a thiamine derivative, in nicotine and uric acid-induced vascular endothelial dysfunction (VED) in rats. Nicotine (2 mg kg(-1)day(-1), i.p., 4 weeks) and uric acid (150 mg kg(-1)day(-1), i.p., 3 weeks) were administered to produce VED in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating serum and aortic concentration of nitrite/nitrate. Further, the integrity of vascular endothelium was assessed using the scanning electron microscopy (SEM) of thoracic aorta. Moreover, the oxidative stress was assessed by estimating serum thiobarbituric acid reactive substances (TBARS) and aortic superoxide anion generation. The administration of nicotine and uric acid produced VED by impairing the integrity of vascular endothelium and subsequently decreasing serum and aortic concentration of nitrite/nitrate and attenuating acetylcholine-induced endothelium dependent relaxation. Further, nicotine and uric acid produced oxidative stress, which was assessed in terms of increase in serum TBARS and aortic superoxide generation. However, treatment with benfotiamine (70 mg kg(-1)day(-1), p.o.) or atorvastatin (30 mg kg(-1)day(-1) p.o., a standard agent) markedly prevented nicotine and uric acid-induced VED and oxidative stress by improving the integrity of vascular endothelium, increasing the concentration of serum and aortic nitrite/nitrate, enhancing the acetylcholine-induced endothelium dependent relaxation and decreasing serum TBARS and aortic superoxide anion generation. Thus, it may be concluded that benfotiamine reduces the oxidative stress and consequently improves the integrity of vascular endothelium and enhances the generation of nitric oxide to prevent nicotine and uric acid-induced experimental VED. PMID:18951979

  7. The effect of erythropoietin on serum uric acid levels during renal ischemia reperfusion injury in rats

    PubMed Central

    Tsompos, Constantinos; Panoulis, Constantinos; Toutouzas, Konstantinos; Zografos, George; Papalois, Apostolos

    2014-01-01

    Objective: The aim of this experimental study was to assess the effect of erythropoietin on a rat model, particularly under a renal ischemia reperfusion protocol. The beneficial or lack of effects of that molecule on the excreted renal product of serum uric acid were studied biochemically. Material and methods: Forty rats were used with a mean weight of 247.7 gr. Serum uric acid levels were measured measured at 60 min after reperfusion (Groups A and C) and at 120 min after reperfusion (groups B and D). Results: 1) Erythropoietin administration non-significantly decreased the serum uric acid levels non-significantly by 0.02 mg/dL [−0.2415423 mg/dL-0.2015423 mg/dL] (p=0.8560), in accordance with the paired t-test (p=0.8438). Reperfusion time non-significantly increased the serum uric acid levels non-significantly by 0.17 mg/dL [−0.0444933 mg/dL-0.3844933 mg/dL] (p=0.1169), in accordance with the paired t-test (p=0.1648). 3) The interaction of erythropoietin administration and reperfusion time non-significantly increased the serum uric acid levels non-significantly by 0.1 mg/dL [−0.0295564 mg/dL-0.2295564 mg/dL] (p=0.1264). Conclusion: Erythropoietin administration, reperfusion time and their interaction have no significant short-term alterations on serum uric acid levels. Conclusions cannot be extracted by non-significant p-values within 2 hours. Obviously, longer study times may permit safer results. PMID:26328161

  8. Leptin and uric acid as predictors of metabolic syndrome in jordanian adults

    PubMed Central

    Ahmad, Mousa N.; Haddad, Fares H.; Azzeh, Firas S.

    2016-01-01

    BACKGROUND/OBJECTIVES Metabolic syndrome (MetS) is a set of interrelated metabolic risk factors that increase the risk of cardiovascular morbidity and mortality. Studies regarding the specificity and sensitivity of serum levels of leptin and uric acid as predictors of MetS are limited. The aim of this study was to evaluate the serum levels of leptin and uric acid in terms of their specificity and sensitivity as predictors of MetS in the studied Jordanian group. SUBJECTS/METHODS In this cross sectional study, 630 adult subjects (308 men and 322 women) were recruited from the King Hussein Medical Center (Amman, Jordan). The diagnosis of MetS was made according to the 2005 International Diabetes Federation criteria. Receiver operating characteristic curves were used to determine the efficacy of serum levels of leptin and uric acid as predictors of MetS in the studied Jordanian group. RESULTS Study results showed that for identification of subjects with MetS risk, area under the curve (AUC) for leptin was 0.721 and 0.683 in men and women, respectively. Serum uric acid levels in men showed no significant association with any MetS risk factors and no significant AUC, while uric acid AUC was 0.706 in women. CONCLUSION Serum leptin levels can be useful biomarkers for evaluation of the risk of MetS independent of baseline obesity in both men and women. On the other hand, serum uric acid levels predicted the risk of MetS only in women. PMID:27478548

  9. Uric acid levels in subjects with bipolar disorder: A comparative meta-analysis.

    PubMed

    Bartoli, Francesco; Crocamo, Cristina; Mazza, Mario Gennaro; Clerici, Massimo; Carrà, Giuseppe

    2016-10-01

    Previous research has hypothesised increased uric acid levels, possibly because of an amplified purinergic metabolism and a reduced adenosine activity, in subjects with bipolar disorder. This systematic review and meta-analysis aimed at estimating if individuals with bipolar disorder had uric acid levels higher than both healthy controls and subjects with major depression (trait marker hypothesis). It also tested if uric acid levels could differ in different phases of bipolar disorder (state marker hypothesis). Meta-analyses were carried out generating pooled standardized mean differences (SMDs), using random-effects models. Heterogeneity between studies was estimated using the I(2) index. Relevant sensitivity and meta-regression analyses were conducted. We searched main Electronic Databases, identifying twelve studies that met our inclusion criteria. Meta-analyses showed increased uric acid levels in individuals with bipolar disorder as compared with both healthy controls (SMD = 0.65, p < 0.001, I(2) = 82.9%) and those with major depression (SMD = 0.46, p < 0.001; I(2) = 68.7%). However, meta-regression analyses confirmed this association only as compared with healthy controls. Finally, though uric acid levels were higher in manic/mixed phases as compared with depressive ones (SMD = 0.34; p = 0.04, I(2) = 58.8%), a sensitivity analysis did not confirm the association. In sum, our meta-analysis shows that subjects with bipolar disorder have uric acid levels higher than healthy controls. The potential role of factors that might clarify the nature of this association deserves additional research.

  10. Serum uric acid levels and long-term outcomes in chronic kidney disease.

    PubMed

    Miyaoka, Tokiko; Mochizuki, Toshio; Takei, Takashi; Tsuchiya, Ken; Nitta, Kosaku

    2014-07-01

    Hyperuricemia is common in chronic kidney disease (CKD), but data regarding the relationship between serum uric acid levels and the long-term outcomes of CKD patients have been limited. The present study evaluated the associations between baseline serum uric acid levels with mortality and end-stage renal disease (ESRD). The subjects of this study were 551 stage 2-4 CKD patients. Cox proportional hazards models were used to evaluate the relationship between serum uric acid tertiles and all-cause mortality, cardiovascular disease (CVD) mortality, 50 % reduction in estimated glomerular filtration rate (eGFR), and development of ESRD, initially without adjustment, and then after adjusting for several groups of covariates. The mean age of the study subjects was 58.5 years, 59.3 % were men, and 10.0 % had diabetes. The mean eGFR was 42.02 ± 18.52 ml/min/1.73 m(2). In all subjects, the mean serum uric acid level was 6.57 ± 1.35 mg/dl, and 52.2 % of study subjects were on hypouricemic therapy (allopurinol; 48.3 %) at baseline. Thirty-one patients (6.1 %) died during a follow-up period of approximately 6 years. There was no significant association between serum uric acid level and all-cause mortality, CVD mortality, development of ESRD and 50 % reduction in eGFR in the unadjusted Cox models. In the adjusted models, hyperuricemia was found to be associated with all-cause mortality and CVD mortality after adjustment with CVD risk factors, kidney disease factors, and allopurinol, but not associated with development of ESRD and 50 % reduction in eGFR. The results of this study showed that hyperuricemia but not serum uric acid levels were associated with all-cause mortality, CVD mortality after adjustments with CVD risk factors, kidney disease factors, and allopurinol in stage 2-4 CKD patients.

  11. Serum uric acid levels during leprosy reaction episodes

    PubMed Central

    Alves-Junior, Eduardo R.; Arruda, Talita A.; Lopes, Jose C.; Fontes, Cor J.F.

    2016-01-01

    Background. Leprosy reactions are acute inflammatory episodes that occur mainly in the multibacillary forms of the disease. The reactions are classified as type 1 (reverse reaction) or type 2 (erythema nodosum leprosum). Leprosy-associated oxidative stress has been widely demonstrated. Several recent studies have shown uric acid (UA) to have antioxidative effects under pathologic conditions. The objective of this study was to assess serum levels of UA in patients with leprosy reactions, with the aim of monitoring their levels before and after treatment, compared with levels in leprosy patients without reactions. Methods. The study included patients aged 18–69 years assisted at a leprosy treatment reference center in the Central Region of Brazil. Patients who were pregnant; were using immunosuppressant drugs or immunobiologicals; or had an autoimmune disease, human immunodeficiency virus infection, acquired immune deficiency syndrome, or tuberculosis were excluded. Upon recruitment, all individuals were clinically assessed for skin lesions and neural or systemic impairment. Some patients had already completed treatment for leprosy, while others were still undergoing treatment or had initiated treatment after being admitted. The treatment of the reactional episode was started only after the initial evaluation. Laboratory assessments were performed upon admission (baseline) and at approximately 30 and 60 days (time points 1 and 2, respectively). Results. A total of 123 leprosy patients were recruited between June 2012 and June 2015; among them, 56, 42, and 25 presented with type 1, type 2, and no reactions, respectively. Serum UA levels were significantly reduced in patients with type 2 leprosy reactions compared with patients in the control group and remained lower in the two subsequent assessments, after initiation of anti-reaction treatments, with similar values to those recorded before the treatment. Discussion. The decreased serum UA levels in patients with

  12. Prognostic Significance of Uric Acid Levels in Ischemic Stroke Patients.

    PubMed

    Zhang, Xia; Huang, Zhi-Chao; Lu, Tao-Sheng; You, Shou-Jiang; Cao, Yong-Jun; Liu, Chun-Feng

    2016-01-01

    The importance and function of serum uric acid (UA) levels in patients with cardiovascular disease or stroke are unclear. We sought to evaluate the appropriate UA levels for stroke patients and the association between endogenous UA levels and clinical outcomes in acute ischemic stroke (AIS) patients, particularly regarding the possible interaction between gender and UA levels with respect to AIS prognosis. We examined 303 patients who had an onset of ischemic stroke within 48 h. Of those, 101 patients received thrombolytic treatment. Serum UA (μmol/L) levels were measured the second morning after admission. Patient prognosis was evaluated 90 days after clinical onset by modified Rankin Scale. Patients were divided into four groups according to serum UA quartiles. A binary multivariate logistic regression model was used to assess clinical relevance in regard to functional outcome and endogenous UA levels. Analysis of subgroups by gender and normal glomerular filtration rate were also been done. Poor functional outcome was associated with older age, history of atrial fibrillation, or higher baseline National Institutes of Health Stroke Scale scores. After adjustment for potential confounders, patients with higher UA levels (>380 μmol/L) or lower UA levels (≤250 μmol/L) were 2-3 times more likely to have a poor outcome (OR 2.95, 95% CI 1.14-7.61; OR 2.78, 95% CI 1.02-7.58, respectively) compared to the baseline group (UA level 316-380 μmol/L). The same results were observed in thrombolyzed patients. Patients with high and low UA levels were 9-18 times more likely to having poor outcomes compared to the baseline group (UA level: 316-380 μmol/L; OR 18.50, 95% CI: 2.041-167.67; OR 9.66, 95% CI 1.42-65.88, respectively). In men, patients with high UA levels were 6 times more likely to have poor outcomes compared to the baseline group (UA level: 279-334 μmol/L; OR 6.10, 95% CI 1.62-22.93). However, female patients with UA level 271-337 μmol/L were seven times more

  13. Lower serum uric acid level predicts mortality in dialysis patients

    PubMed Central

    Bae, Eunjin; Cho, Hyun-Jeong; Shin, Nara; Kim, Sun Moon; Yang, Seung Hee; Kim, Dong Ki; Kim, Yong-Lim; Kang, Shin-Wook; Yang, Chul Woo; Kim, Nam Ho; Kim, Yon Su; Lee, Hajeong

    2016-01-01

    Abstract We evaluated the impact of serum uric acid (SUA) on mortality in patients with chronic dialysis. A total of 4132 adult patients on dialysis were enrolled prospectively between August 2008 and September 2014. Among them, we included 1738 patients who maintained dialysis for at least 3 months and had available SUA in the database. We categorized the time averaged-SUA (TA-SUA) into 5 groups: <5.5, 5.5–6.4, 6.5–7.4, 7.5–8.4, and ≥8.5 mg/dL. Cox regression analysis was used to calculate the hazard ratio (HR) of all-cause mortality according to SUA group. The mean TA-SUA level was slightly higher in men than in women. Patients with lower TA-SUA level tended to have lower body mass index (BMI), phosphorus, serum albumin level, higher proportion of diabetes mellitus (DM), and higher proportion of malnourishment on the subjective global assessment (SGA). During a median follow-up of 43.9 months, 206 patients died. Patients with the highest SUA had a similar risk to the middle 3 TA-SUA groups, but the lowest TA-SUA group had a significantly elevated HR for mortality. The lowest TA-SUA group was significantly associated with increased all-cause mortality (adjusted HR, 1.720; 95% confidence interval, 1.007–2.937; P = 0.047) even after adjusting for demographic, comorbid, nutritional covariables, and medication use that could affect SUA levels. This association was prominent in patients with well nourishment on the SGA, a preserved serum albumin level, a higher BMI, and concomitant DM although these parameters had no significant interaction in the TA-SUA-mortality relationship except DM. In conclusion, a lower TA-SUA level <5.5 mg/dL predicted all-cause mortality in patients with chronic dialysis. PMID:27310949

  14. Creatinine adjustment of spot urine samples and 24 h excretion of iodine, selenium, perchlorate, and thiocyanate.

    PubMed

    Ohira, Shin-ichi; Kirk, Andrea B; Dyke, Jason V; Dasgupta, Purnendu K

    2008-12-15

    Creatinine (CR) adjustment is widely used for the estimation of urinary 24 h excretion from spot urine samples. We have compared CR-adjusted values for urinary iodine, selenium, perchlorate, and thiocyanate to measured 24 h excretion. The urine samples were collected from a cohort of 14 breastfeeding mothers with both spot samples and 24 h collection, 52 24 h and spot sample pairs where the 24 h CR value fell within the "normal" adult female CR excretion range of 0.6-1.6 g/day were considered for this analysis. In addition, a nonlactating female and a male subject provided all micturitions for 1 and 5 days, respectively. Creatinine was analyzed with a Jáffe reaction-based automated analyzer. Iodine and selenium were determined with induction coupled plasma-mass spectrometry (ICP-MS). Perchlorate and thiocyanate were measured with ion chromatography (IC)-isotope dilution tandem mass spectrometry (MS/MS). Creatinine-adjusted values were poor substitutes of the actual 24 h excretion values (average deviation +/-69, 78, 105, and 104% for iodine, selenium, perchlorate, and thiocyanate, respectively.). Over a 5 day period, the 24 h iodine excretion predicted based on creatinine adjustment of spot samples for the same individual deviated between -83.5 to +101% from the actual measured value, the minimum absolute error being 2.5%. Creatinine adjustment for estimation of 24 h excretion from spot samples was not effective for iodine, selenium, perchlorate, or thiocyanate.

  15. Two low-cost digital camera-based platforms for quantitative creatinine analysis in urine.

    PubMed

    Debus, Bruno; Kirsanov, Dmitry; Yaroshenko, Irina; Sidorova, Alla; Piven, Alena; Legin, Andrey

    2015-10-01

    In clinical analysis creatinine is a routine biomarker for the assessment of renal and muscular dysfunctions. Although several techniques have been proposed for a fast and accurate quantification of creatinine in human serum or urine, most of them require expensive or complex apparatus, advanced sample preparation or skilled operators. To circumvent these issues, we propose two home-made platforms based on a CD Spectroscope (CDS) and Computer Screen Photo-assisted Technique (CSPT) for the rapid assessment of creatinine level in human urine. Both systems display a linear range (r(2) = 0.9967 and 0.9972, respectively) from 160 μmol L(-1) to 1.6 mmol L(-1) for standard creatinine solutions (n = 15) with respective detection limits of 89 μmol L(-1) and 111 μmol L(-1). Good repeatability was observed for intra-day (1.7-2.9%) and inter-day (3.6-6.5%) measurements evaluated on three consecutive days. The performance of CDS and CSPT was also validated in real human urine samples (n = 26) using capillary electrophoresis data as reference. Corresponding Partial Least-Squares (PLS) regression models provided for mean relative errors below 10% in creatinine quantification.

  16. Effect of glucagon infusion on the renal clearance of amylase relative to creatinine.

    PubMed

    Tedesco, F J; Davila, E; Gardner, L B

    1978-10-01

    Recent data seem to support a tubular defect as the mechanism of the elevated renal clearance of amylase relative to creatinine in acute pancreatitis. Glucagon has been proposed by some to be an important factor in this phenomenon. To examine the role of glucagon as this "tubular dysfunction factor", we investigated the effect of intravenously infused glucagon on the fractional excretion of amylase and the tubular handling of a low molecular weight protein, beta2 microglobulin, in normal, healthy volunteers. At glucagon levels far in excess of those seen in pancreatitis, the clearance ratio of beta2 microglobulin relative to creatinine increased, whereas the clearance ratio of amylase relative to creatinine did not increase above the normal range. The dissociation between beta2 microglobulin clearance and amylase clearance allows one to question the theory that tubular dysfunction is the mechanism of the elevated renal clearance of amylase relative to creatinine in acute pancreatitis. Glucagon does not appear to be the sole factor responsible for the elevation of renal clearance of amylase relative to creatinine in acute pancreatitis.

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

    PubMed

    Smith, C R; Schwartz, S I

    1983-09-01

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

  18. CREATININE DETERMINATION IN URINE BY LIQUID CHROMATOGRAPHY-ELECTROSPRAY IONIZATION-TANDEM MASS SPECTROMETRY METHOD.

    PubMed

    Dereziński, Paweł; Klupczyńska, Agnieszka; Sawicki, Wojciech; Kokot, Zenon J

    2016-01-01

    Creatinine determination in urine is used to estimate the completeness of the 24-h urine collection, compensation for variable diuresis and as a preliminary step in protein profiling in urine. Despite the fact that a wide range of methods of measuring creatinine level in biofluids has been developed, many of them are adversely affected by interfering substances. A new liquid chromatography-tandem mass spectrometry method for creatinine determination in urine has been developed. Chromatographic separation was performed by applying C18 column and a gradient elution. Analyses were carried out on a triple quadrupole mass spectrometer equipped with an electrospray ion source. The developed method was fully validated according to the international guidelines. The quantification range of the method was 5-1500 ng/mL, which corresponds to 1-300 mg/dL in urine. Limit of detection and quantitation were 2 and 5 ng/mL, respectively. Additionally, the comparison of creatinine determination by newly developed method to the colorimetric method was performed. The method enables the determination of creatinine in urine samples with a minimal sample preparation, excellent sensitivity and prominent selectivity. Since mass spectrometry allows to measure a number of compounds simultaneously, a future perspective would be to incorporate the determination of other clinically important compounds excreted in urine. PMID:27180423

  19. Two low-cost digital camera-based platforms for quantitative creatinine analysis in urine.

    PubMed

    Debus, Bruno; Kirsanov, Dmitry; Yaroshenko, Irina; Sidorova, Alla; Piven, Alena; Legin, Andrey

    2015-10-01

    In clinical analysis creatinine is a routine biomarker for the assessment of renal and muscular dysfunctions. Although several techniques have been proposed for a fast and accurate quantification of creatinine in human serum or urine, most of them require expensive or complex apparatus, advanced sample preparation or skilled operators. To circumvent these issues, we propose two home-made platforms based on a CD Spectroscope (CDS) and Computer Screen Photo-assisted Technique (CSPT) for the rapid assessment of creatinine level in human urine. Both systems display a linear range (r(2) = 0.9967 and 0.9972, respectively) from 160 μmol L(-1) to 1.6 mmol L(-1) for standard creatinine solutions (n = 15) with respective detection limits of 89 μmol L(-1) and 111 μmol L(-1). Good repeatability was observed for intra-day (1.7-2.9%) and inter-day (3.6-6.5%) measurements evaluated on three consecutive days. The performance of CDS and CSPT was also validated in real human urine samples (n = 26) using capillary electrophoresis data as reference. Corresponding Partial Least-Squares (PLS) regression models provided for mean relative errors below 10% in creatinine quantification. PMID:26454461

  20. Technical note: variation in muscle mass in wild chimpanzees: application of a modified urinary creatinine method.

    PubMed

    Emery Thompson, Melissa; Muller, Martin N; Wrangham, Richard W

    2012-12-01

    Individual body size and composition are important variables for a variety of questions about the behavioral ecology and life histories of non-human primates. Standard methodologies for obtaining body mass involve either capture, which poses risks to the subject, or provisioning, which can disrupt the processes being studied. There are no methods currently available to assess body composition from living animals in the wild. Because of its derivation in muscle, the amount of creatinine that an individual excretes in 24 hours is a reliable and frequently used indicator of relative muscle mass in humans and laboratory animals. Although it is not feasible to collect 24-hour urine samples from wild primates, we apply here a simple method to approximate muscle mass variation from collections of spot urine samples. Specific gravity (SG), an alternative method for assessing urinary water content, is both highly correlated to creatinine and free of mass-dependent effects. Individuals with greater muscle mass should excrete more creatinine for a given SG. We examine this relationship in a dataset of 12,598 urine samples from wild chimpanzees in the Kibale National Park, Uganda. As expected from known differences in body composition, the slope of the relationship between SG and creatinine is significantly greater in adult males than adult females and in adults versus immature individuals. Growth curves generated through this method closely approximate published weight curves for wild chimpanzees. Consistent with the role of testosterone in muscle anabolism, urinary testosterone predicted relative creatinine excretion among adult male chimpanzees. PMID:23077085

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

    PubMed

    Smith, C R; Schwartz, S I

    1983-09-01

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

  2. Creatinine Clearance Is Associated with Toxicity from Molecularly Targeted Agents in Phase I Trials

    PubMed Central

    Basu, B.; Vitfell-Pedersen, J.; Moreno Garcia, V.; Puglisi, M.; Tjokrowidjaja, A.; Shah, K.; Malvankar, S.; Anghan, B.; de Bono, J.S.; Kaye, S.B.; Molife, L.R.; Banerji, U.

    2012-01-01

    Objectives This study aimed to evaluate any correlations between baseline creatinine clearance and the development of grade 3/4 toxicities during treatment within oncology phase I trials of molecularly targeted agents where entry criteria mandate a serum creatinine of ≤1.5 × the upper limit of normal. Methods Documented toxicity and creatinine clearance (calculated by the Cockcroft-Gault formula) from all patients treated with molecularly targeted agents in the context of phase I trials within our centre over a 5-year period were analyzed. Results Data from 722 patients were analyzed; 116 (16%) developed at least one episode of grade 3/4 toxicity. Patients who developed a late-onset (>1 cycle) grade 3/4 toxicity had a lower creatinine clearance than those who did not (82.69 ml/min vs. 98.97 ml/min; p = < 0.001). Conclusion Creatinine clearance (even when within normal limits) should be studied as a potential factor influencing late toxicities in the clinical trials of molecularly targeted anti-cancer drugs. PMID:22889980

  3. Is the fasting calcium/creatinine a bone resorption marker in patients with calcium renal stones?

    PubMed

    Arrabal-Polo, Miguel Angel; Arrabal-Martin, Miguel; Poyatos-Andujar, Antonio; Cardenas-Grande, Encarnacion; Merino-Salas, Sergio; Zuluaga-Gomez, Armando

    2012-06-01

    Osteoporosis and osteopenia are an important endocrine-metabolic disease that affect women and men from a certain age and it has a high risk and health cost. The aim of this short communication is to show that fasting calcium/creatinine ratio in patients with calcium stones is a marker of bone resorption.We studied 180 patients with renal stones with calcium composition and the relationship of them between the calcium/creatinine in urine after 8 h of fasting with bone densitometry (T-score) and values of bone resorption marker β-crosslaps (ng/ml). The Pearson correlation test was applied for the analysis of linear correlations between quantitative variables.We have observed a statistically significant positive linear correlation between the fasting calcium/creatinine and serum and β-crosslaps (R = 0.534, p < 0.0001) and a statistically significant negative linear correlation between fasting calcium/creatinine and T-score of bone densitometry in hip (R = -0.237, p = 0.002), femoral neck (R = -0.217, p = 0.009) and lumbar spine (R = 0.292, p = 0.001).The fasting ratio calcium/creatinine in urine is associated with increased levels of β-crosslaps marker and therefore may be useful as a marker of bone resorption in these patients.

  4. 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...

  5. Uric acid attenuates nitric oxide production by decreasing the interaction between endothelial nitric oxide synthase and calmodulin in human umbilical vein endothelial cells: a mechanism for uric acid-induced cardiovascular disease development.

    PubMed

    Park, Jung-Hyun; Jin, Yoon Mi; Hwang, Soojin; Cho, Du-Hyong; Kang, Duk-Hee; Jo, Inho

    2013-08-01

    The elevated level of uric acid in the body is associated with increased risk of cardiovascular diseases, which is mediated by endothelial dysfunction. However, its underlying mechanism is not fully understood, although dysregulation of endothelial nitric oxide (NO) production is likely to be involved. Using human umbilical vascular endothelial cells (HUVEC), we explored the molecular mechanism of uric acid on endothelial NO synthase (eNOS) activity and NO production. Although high dose of uric acid (12mg/dl for 24h treatment) significantly decreased eNOS activity and NO production, it did not alter eNOS expression and phosphorylations at eNOS-Ser(1177), eNOS-Thr(495) and eNOS-Ser(114). Under this condition, we also found no alterations in the dimerization and acetylation of eNOS, compared with the control. Furthermore, uric acid did not change the activity of arginase II, an enzyme degrading l-arginine, a substrate of eNOS, and intracellular level of calcium, a cofactor for eNOS activation. We also found that uric acid did not alter xanthine oxidase activity, suggesting no involvement of xanthine oxidase-derived O2(-) production in the observed inhibitory effects. In vitro and in cell coimmunoprecipitation studies, however, revealed that uric acid significantly decreased the interaction between eNOS and calmodulin (CaM), an eNOS activator, although it did not change the intracellular CaM level. Like in HUVEC, uric acid also decreased eNOS-CaM interaction in bovine aortic EC. Finally, uric acid attenuated ionomycin-induced increase in the interaction between eNOS and CaM. This study suggests firstly that uric acid decreased eNOS activity and NO production through reducing the binding between eNOS and CaM in EC. Our result may provide molecular mechanism by which uric acid induces endothelial dysfunction.

  6. Malleable and Recyclable Poly(urea-urethane) Thermosets bearing Hindered Urea Bonds.

    PubMed

    Zhang, Yanfeng; Ying, Hanze; Hart, Kevin R; Wu, Yuxiao; Hsu, Aaron J; Coppola, Anthony M; Kim, Tae Ann; Yang, Ke; Sottos, Nancy R; White, Scott R; Cheng, Jianjun

    2016-09-01

    Poly(urea-urethane) thermosets containing the 1-tert-butylethylurea (TBEU) structure feature a reversible dissociation/association process of their covalent linkages under mild conditions. Unlike conventional thermosets, TBEU-based poly(urea-urethane) thermosets maintain their malleability after curing. Under high temperature (100 °C) and applied pressure (300 kPa), ground TBEU thermoset powder can be remolded to bulk after 20 min. PMID:27374855

  7. Urea transporters and sweat response to uremia.

    PubMed

    Keller, Raymond W; Bailey, James L; Wang, Yanhua; Klein, Janet D; Sands, Jeff M

    2016-06-01

    In humans, urea is excreted in sweat, largely through the eccrine sweat gland. The urea concentration in human sweat is elevated when compared to blood urea nitrogen. The sweat urea nitrogen (UN) of patients with end-stage kidney disease (ESRD) is increased when compared with healthy humans. The ability to produce sweat is maintained in the overwhelming majority of ESRD patients. A comprehensive literature review found no reports of sweat UN neither in healthy rodents nor in rodent models of chronic kidney disease (CKD). Therefore, this study measured sweat UN concentrations in healthy and uremic rats. Uninephrectomy followed by renal artery ligation was used to remove 5/6 of renal function. Rats were then fed a high-protein diet to induce uremia. Pilocarpine was used to induce sweating. Sweat droplets were collected under oil. Sweat UN was measured with a urease assay. Serum UN was measured using a fluorescent ortho-pthalaldehyde reaction. Immunohistochemistry (IHC) was accomplished with a horseradish peroxidase and diaminobenzidine technique. Sweat UN in uremic rats was elevated greater than two times compared to healthy pair-fed controls (220 ± 17 and 91 ± 15 mmol/L, respectively). Post hoc analysis showed a significant difference between male and female uremic sweat UN (279 ± 38 and 177 ± 11 mmol/L, respectively.) IHC shows, for the first time, the presence of the urea transporters UT-B and UT-A2 in both healthy and uremic rat cutaneous structures. Future studies will use this model to elucidate how rat sweat UN and other solute excretion is altered by commonly prescribed diuretics.

  8. Urea transporters and sweat response to uremia.

    PubMed

    Keller, Raymond W; Bailey, James L; Wang, Yanhua; Klein, Janet D; Sands, Jeff M

    2016-06-01

    In humans, urea is excreted in sweat, largely through the eccrine sweat gland. The urea concentration in human sweat is elevated when compared to blood urea nitrogen. The sweat urea nitrogen (UN) of patients with end-stage kidney disease (ESRD) is increased when compared with healthy humans. The ability to produce sweat is maintained in the overwhelming majority of ESRD patients. A comprehensive literature review found no reports of sweat UN neither in healthy rodents nor in rodent models of chronic kidney disease (CKD). Therefore, this study measured sweat UN concentrations in healthy and uremic rats. Uninephrectomy followed by renal artery ligation was used to remove 5/6 of renal function. Rats were then fed a high-protein diet to induce uremia. Pilocarpine was used to induce sweating. Sweat droplets were collected under oil. Sweat UN was measured with a urease assay. Serum UN was measured using a fluorescent ortho-pthalaldehyde reaction. Immunohistochemistry (IHC) was accomplished with a horseradish peroxidase and diaminobenzidine technique. Sweat UN in uremic rats was elevated greater than two times compared to healthy pair-fed controls (220 ± 17 and 91 ± 15 mmol/L, respectively). Post hoc analysis showed a significant difference between male and female uremic sweat UN (279 ± 38 and 177 ± 11 mmol/L, respectively.) IHC shows, for the first time, the presence of the urea transporters UT-B and UT-A2 in both healthy and uremic rat cutaneous structures. Future studies will use this model to elucidate how rat sweat UN and other solute excretion is altered by commonly prescribed diuretics. PMID:27273880

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

    SciTech Connect

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

    2007-02-01

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

  10. 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. ...

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

    PubMed

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

    2016-01-01

    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 urea···urea α-tape hydrogen bonding interactions.

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 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 nitrate-urea complex may be safely used as a component of articles intended for use in...

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 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 nitrate-urea complex may be safely used as a component of articles intended for use in...

  14. 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...

  15. 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 nitrate-urea complex may be safely used as a component of articles intended for use in...

  16. Speed associated with plasma pH, oxygen content, total protein and urea in an 80 km race.

    PubMed

    Hoffman, R M; Hess, T M; Williams, C A; Kronfeld, D S; Griewe-Crandell, K M; Waldron, J E; Graham-Thiers, P M; Gay, L S; Splan, R K; Saker, K E; Harris, P A

    2002-09-01

    To test the hypothesis that endurance performance may be related quantitatively to changes in blood, we measured selected blood variables then determined their reference ranges and associations with speed during an 80 km race. The plan had 46 horses in a 2 x 2 factorial design testing a potassium-free electrolyte mix and a vitamin supplement. Blood samples were collected before the race, at 21, 37, 56 and 80 km, and 20 min after finishing, for assay of haematocrit, plasma pH, pO2, pCO2, [Na+], [K+], [Ca++], [Mg++], [Cl-], lactate, glucose, urea, cortisol, alpha-tocopherol, ascorbate, creatine kinase, aspartate amino transferase, lipid hydroperoxides, total protein, albumin and creatinine, and erythrocyte glutathione and glutathione peroxidase. Data from 34 finishers were analysed statistically. Reference ranges for resting and running horses were wide and overlapping and, therefore, limiting with respect to evaluation of individual horses. Speed correlations were most repeatable, with variables reflecting blood oxygen transport (enabling exercise), acidity and electrolytes (limiting exercise) and total protein (enabling then, perhaps, limiting). Stepwise regressions also included plasma urea concentration (limiting). The association of speed with less plasma acidity and urea suggests the potential for fat adaptation and protein restriction in endurance horses, as found previously in Arabians performing repeated sprints. Conditioning horses fed fat-fortified and protein-restricted diets may not only improve performance but also avoid grain-associated disorders.

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

    USGS Publications Warehouse

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

    2010-01-01

    Concentrations of organic biomarkers and concentrations of phosphorus in soil cores can potentially be used as proxies for historic population densities of wading birds on tree islands in the Florida Everglades. This report focuses on establishing a link between the organic biomarker uric acid found in wading bird guano and the high phosphorus concentrations in tree island soils in the Florida Everglades. Uric acid was determined in soil core sections, in surface samples, and in bird guano by using a method of high-performance liquid chromatography-mass spectrometry (HPLC-MS) developed for this purpose. Preliminary results show an overall correlation between uric acid and total phosphorus in three soil cores, with a general trend of decreasing concentrations of both uric acid and phosphorus with depth. However, we have also found no uric acid in a soil core having high concentrations of phosphorus. We believe that this result may be explained by different geochemical circumstances at that site.

  18. Tuna extract reduces serum uric acid in gout-free subjects with insignificantly high serum uric acid: A randomized controlled trial

    PubMed Central

    Kubomura, Daiki; Yamada, Masanori; Masui, Ayano

    2016-01-01

    Long-term reduction of serum urate levels is vital in the treatment of gout. However, it is difficult to convince gout-free individuals of the necessity of treatment as few appropriate over-the-counter remedies and dietary supplements are available. Therefore, the present study aimed to investigate the antihyperuricemic efficacy and safety of a tuna extract containing the imidazole compounds to evaluate its potential as a functional food ingredient. A randomized, 4-week, double-blind, placebo-controlled study was conducted. A total of 48 male gout-free subjects with insignificantly high serum uric acid were randomly assigned to low- and high-dose tuna extract groups or a placebo group. The efficacy of the extract was assessed by measuring serum uric acid levels. Furthermore, a safety assessment was performed by physical parameters, hematology, blood biochemistry and urinalysis. The results indicated that the uric acid level was decreased at week 4 during the intervention in the tuna extract groups (low and high dose, −0.23 and −0.34 mg/dl, respectively) compared to the placebo group (−0.07 mg/dl). At week 4 after the intervention, a significant reduction in uric acid levels (−0.41 mg/dl; P<0.05) was observed in the high-dose tuna extract group compared with the placebo group (+0.11 mg/dl). No dose-related adverse events were observed during and following the intervention. Therefore, the present results suggest that oral administration of tuna extract containing the imidazole compounds has hypouricemic activity with no undesirable side effects. PMID:27446553

  19. [Creatinine and calcium in urine and blood after brief exposure to magnetic fields].

    PubMed

    Schmidt, F; Mannsåker, T; Løvlie, R

    1999-02-10

    In this experimental study, 35 males were exposed to artificial magnetic fields. The fields were produced by a set of Helmholz coils internally isolated by a Faraday cage which effectively eliminated electrical fields. Each participant stayed inside the coils for 40 minutes on two occasions with an interval of seven days, but was actually only once exposed to a static magnetic field (9.6 mT) and oscillating magnetic fields of variable frequency and strength. Urine and blood samples were taken before and after exposure, and before and after non-exposure. Analysis detected significant changes in serum creatinine level after exposure (p < 0.0001). The changes in serum creatinine level in the nonexposed situation were significantly smaller than the changes found in the exposed situation (p < 0.0001). The changes i urine creatinine after 40 minutes of exposure was also found to be significant (p < 0.01). Exposure to magnetic fields may induce biological reactions.

  20. Creatinine determination according to Jaffe—what does it stand for?

    PubMed Central

    Speeckaert, Marijn M.

    2011-01-01

    In 1886, Max Jaffe discovered a reaction of creatinine with picric acid in an alkaline environment. Although the manuscript describes the nature of a precipitate and does not deal with an analytical assay, Jaffe's landmark paper elucidated the basic principles of the creatinine determination method (originally developed by Otto Folin), which became immensely popular and has easily withstood the test of time. Despite the advent of the enzymatic creatinine analysis, the analytical method is still popular due to its simplicity and low cost. As there is no standard recipe for the ‘Jaffe’ method, much methodological variation has occurred over time. This lack of methodological standardization implies that even in the 21st century, improving the interchangeability of Jaffe results is still an issue. PMID:25984118

  1. 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

  2. Creatinine measurements often yielded false estimates of progression in chronic renal failure

    SciTech Connect

    Walser, M.; Drew, H.H.; LaFrance, N.D.

    1988-09-01

    In 9 of 22 observation periods (lasting an average of 15 months) in 17 patients with moderate to severe chronic renal failure (GFR 4 to 23 ml/min), rates of progression as estimated from the linear regression on time of 24-hour creatinine clearance (b1) differed significantly from rates of progression as estimated from the regression on time of urinary clearance of 99mTc-DTPA (b2), during all or part of the period of observation. b1 exceeded b2 in four cases and was less than b2 in the other five. Thus there were gradual changes in the fractional tubular secretion of creatinine in individual patients, in both directions. Owing to these changes, measurements of creatinine clearance gave erroneous impressions of the rate or existence of progression during all or a portion of the period of observation in nearly half of these patients. In the 22 studies as a group, using the entire periods of observation, b1 indicated significantly more rapid progression (by 0.18 +/- 0.06 ml/min/month, P less than 0.01) than did b2, and had a significantly greater variance. Measurements of progression based on the rate of change of reciprocal plasma creatinine (multiplied by an average rate of urinary creatinine excretion in each study) were equally misleading, even though less variable. We conclude that sequential creatinine measurements are often misleading as measures of progression and should, when feasible, be replaced by urinary clearance of isotopes in following patients with chronic renal failure.

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

    PubMed

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

    2014-10-15

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

  4. 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.

  5. Amylase: creatinine clearance ratio and urinary excretion of lysozyme in acute pancreatitis and acute duodenal perforation.

    PubMed

    Berger, G M; Cowlin, J; Turner, T J

    1976-09-18

    The amylase:creatinine clearance ratio in patients suffering from acute pancreatitis or acute duodenal perforation was higher than normal in both groups of patients. These findings cast doubt on the value of this parameter as a specific index of acute pancreatitis. The mechanism or mechanisms underlying the increased amylase excretion have not been determined. However, the markedly elevated urinary excretion of lysozyme observed in some patients suggests, by analogy, that diminished tubular reabsorption of amylase may contribute towards the elevated amylase:creatinine ratio.

  6. Reconsidering the Lack of Urea Toxicity in Dialysis Patients.

    PubMed

    Massy, Ziad A; Pietrement, Christine; Touré, Fatouma

    2016-09-01

    Urea is an old uremic toxin which has been used for many years as a global biomarker of CKD severity and dialysis adequacy. Old studies were not in favor of its role as a causal factor in the pathogenesis of complications associated with the uremic state. However, recent experimental and clinical evidence is compatible with both direct and indirect toxicity of urea, particularly via the deleterious actions of urea-derived carbamylated molecules. Further studies are clearly needed to explore the potential relevance of urea-related CKD complications for patient management, in particular the place of new therapeutic strategies to prevent urea toxicity.

  7. Reconsidering the Lack of Urea Toxicity in Dialysis Patients.

    PubMed

    Massy, Ziad A; Pietrement, Christine; Touré, Fatouma

    2016-09-01

    Urea is an old uremic toxin which has been used for many years as a global biomarker of CKD severity and dialysis adequacy. Old studies were not in favor of its role as a causal factor in the pathogenesis of complications associated with the uremic state. However, recent experimental and clinical evidence is compatible with both direct and indirect toxicity of urea, particularly via the deleterious actions of urea-derived carbamylated molecules. Further studies are clearly needed to explore the potential relevance of urea-related CKD complications for patient management, in particular the place of new therapeutic strategies to prevent urea toxicity. PMID:27174444

  8. Atomic scale insights into urea-peptide interactions in solution.

    PubMed

    Steinke, Nicola; Gillams, Richard J; Pardo, Luis Carlos; Lorenz, Christian D; McLain, Sylvia E

    2016-02-01

    The mechanism by which proteins are denatured by urea is still not well understood, especially on the atomic scale where these interactions occur in vivo. In this study, the structure of the peptide GPG has been investigated in aqueous urea solutions in order to understand the combination of roles that both urea and water play in protein unfolding. Using a combination of neutron diffraction enhanced by isotopic substitution and computer simulations, it was found, in opposition with previous simulations studies, that urea is preferred over water around polar and charged portions of the peptides. Further, it appears that while urea directly replaces water around the nitrogen groups on GPG that urea and water occupy different positions around the peptide bond carbonyl groups. This suggests that urea may in fact weaken the peptide bond, disrupting the peptide backbone, thus ultimately causing denaturation.

  9. 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.

  10. 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…

  11. Spectrophotometric determination of uric acid and some redeterminations of its solubility

    USGS Publications Warehouse

    Norton, D.R.; Plunkett, M.A.; Richards, F.A.

    1954-01-01

    The present study was initiated in order to develop a rapid and accurate method for the determination of uric acid in fresh, brackish, and sea water. It was found that the spectrophotometric determination of uric acid based upon its reaction with arsenophosphotungstic acid reagent in the presence of cyanide ion meets this objective. The absorbancy of the blue complex was measured at 890 m??. Slight variations from Beer's law were generally found. The results show the effects of pH, reaction time, concentration of reagents, and temperature upon color development and precipitate formation. Disodium dihydrogen ethylenediamine tetraacetate (Versene) was used as a buffering and complexirig agent. The results are significant in that they give the absorption spectrum of the blue complex and the effects of variables upon its absorbancy. Studies were made with the method to determine the stability of reagents and standard solutions and to determine the rate of bacterial decomposition of uric acid. Measurements of the solubility of uric acid are reported.

  12. Dietary fructose in relation to blood pressure and serum uric acid in adolescent boys and girls.

    PubMed

    Bobridge, K S; Haines, G L; Mori, T A; Beilin, L J; Oddy, W H; Sherriff, J; O'Sullivan, T A

    2013-04-01

    Evidence that fructose intake may modify blood pressure is generally limited to adult populations. This study examined cross-sectional associations between dietary intake of fructose, serum uric acid and blood pressure in 814 adolescents aged 13-15 years participating in the Western Australian Pregnancy Cohort (Raine) Study. Energy-adjusted fructose intake was derived from 3-day food records, serum uric acid concentration was assessed using fasting blood and resting blood pressure was determined using repeated oscillometric readings. In multivariate linear regression models, we did not see a significant association between fructose and blood pressure in boys or girls. In boys, fructose intake was independently associated with serum uric acid (P<0.01), and serum uric acid was independently associated with systolic blood pressure (P<0.01) and mean arterial pressure (P<0.001). Although there are independent associations, there is no direct relationship between fructose intake and blood pressure. Our data suggest that gender may influence these relationships in adolescence, with significant associations observed more frequently in boys than girls.

  13. 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

  14. Small-Molecule Inhibitors of Urea Transporters

    PubMed Central

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

    2015-01-01

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

  15. Neurological implications of urea cycle disorders.

    PubMed

    Gropman, A L; Summar, M; Leonard, J V

    2007-11-01

    The urea cycle disorders constitute a group of rare congenital disorders caused by a deficiency of the enzymes or transport proteins required to remove ammonia from the body. Via a series of biochemical steps, nitrogen, the waste product of protein metabolism, is removed from the blood and converted into urea. A consequence of these disorders is hyperammonaemia, resulting in central nervous system dysfunction with mental status changes, brain oedema, seizures, coma, and potentially death. Both acute and chronic hyperammonaemia result in alterations of neurotransmitter systems. In acute hyperammonaemia, activation of the NMDA receptor leads to excitotoxic cell death, changes in energy metabolism and alterations in protein expression of the astrocyte that affect volume regulation and contribute to oedema. Neuropathological evaluation demonstrates alterations in the astrocyte morphology. Imaging studies, in particular (1)H MRS, can reveal markers of impaired metabolism such as elevations of glutamine and reduction of myoinositol. In contrast, chronic hyperammonaemia leads to adaptive responses in the NMDA receptor and impairments in the glutamate-nitric oxide-cGMP pathway, leading to alterations in cognition and learning. Therapy of acute hyperammonaemia has relied on ammonia-lowering agents but in recent years there has been considerable interest in neuroprotective strategies. Recent studies have suggested restoration of learning abilities by pharmacological manipulation of brain cGMP with phosphodiesterase inhibitors. Thus, both strategies are intriguing areas for potential investigation in human urea cycle disorders.

  16. 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

  17. 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

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

    PubMed

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

    2002-03-01

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

  19. 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.

  20. 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/EBPα, PPARγ, 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

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

    PubMed

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

    1972-10-01

    The statement made in some standard textbooks that Benedict's qualitative test gives a green, yellow, or orange-red precipitate with pure solutions of glucose of varying strength has been shown to be incorrect. Pure solutions of glucose give only a bright red precipitate at all concentrations. These changes in the colour of the suspensions are observed with urinary glucose only. The difference in the action of glucose in water and in urine has been shown to be mostly due to creatinine and to a small extent to the histidine content of urine. The colour of the precipitate depends not only on the concentration of glucose but also on that of creatinine. An increase in concentration of creatinine tends to make the precipitate more yellow. Histidine has a similar though much smaller effect. Attention has been drawn to possible errors in the semi-quantitative assay of urinary glucose by Benedict's test arising out of variation in concentration of creatinine and histidine. PMID:4646301

  2. Mode of action of creatinine on colour of cuprous oxide precipitate in Benedict's qualitative sugar test.

    PubMed

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

    1972-10-01

    Creatinine appears to alter the colour and bulky nature of the cuprous oxide precipitate not by altering the chemical composition of the precipitate but by the physical process of retardation of the growth of newly formed yellow cuprous oxide crystals to large red crystals by adhering to their surface and blocking some sites for further crystal growth. PMID:4646302

  3. Biomarkers and creatinine in AKI: the trough of disillusionment or the slope of enlightenment?

    PubMed

    Endre, Zoltán H; Pickering, John W

    2013-10-01

    Assessment of acute kidney biomarkers against changes in plasma creatinine is beset by issues of heterogeneity of study cohorts and timing of sampling. Siew and colleagues attempt to minimize these issues in a case-control study of three biomarkers in the intensive care unit. The results highlight the inherent methodological difficulties and the need to reference structural injury biomarkers against more meaningful outcomes.

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

    PubMed Central

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

    1972-01-01

    The statement made in some standard textbooks that Benedict's qualitative test gives a green, yellow, or orange-red precipitate with pure solutions of glucose of varying strength has been shown to be incorrect. Pure solutions of glucose give only a bright red precipitate at all concentrations. These changes in the colour of the suspensions are observed with urinary glucose only. The difference in the action of glucose in water and in urine has been shown to be mostly due to creatinine and to a small extent to the histidine content of urine. The colour of the precipitate depends not only on the concentration of glucose but also on that of creatinine. An increase in concentration of creatinine tends to make the precipitate more yellow. Histidine has a similar though much smaller effect. Attention has been drawn to possible errors in the semi-quantitative assay of urinary glucose by Benedict's test arising out of variation in concentration of creatinine and histidine. PMID:4646301

  5. Urine albumin to creatinine ratio: A marker of early endothelial dysfunction in youth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The urine albumin-to-creatinine ratio (UACR) is a useful predictor of cardiovascular (CV) events in adults. Its relationship to vascular function in children is not clear. We investigated whether UACR was related to insulin resistance and endothelial function, a marker of subclinical atherosclerosis...

  6. Specificity of increased amylase to creatinine clearance ratio in acute pancreatitis.

    PubMed

    Lankisch, P G; Koop, H; Otto, J; Oberdieck, U; Winckler, K; Wolfrum, D I

    1977-01-01

    The amylase to creatinine clearance ratio was found to be normal in 11 of 33 patients with acute pancreatitis. The ratio was elevated in 10 of 19 patients with renal insufficiency. Thus, it does not seem to be a specific index in the diagnosis of acute pancreatitis.

  7. A New Equation to Estimate Muscle Mass from Creatinine and Cystatin C

    PubMed Central

    Kim, Cheol-Ho; Kim, Kwang-il; Chin, Ho Jun; Lee, Hajeong

    2016-01-01

    Background With evaluation for physical performance, measuring muscle mass is an important step in detecting sarcopenia. However, there are no methods to estimate muscle mass from blood sampling. Methods To develop a new equation to estimate total-body muscle mass with serum creatinine and cystatin C level, we designed a cross-sectional study with separate derivation and validation cohorts. Total body muscle mass and fat mass were measured using dual-energy x-ray absorptiometry (DXA) in 214 adults aged 25 to 84 years who underwent physical checkups from 2010 to 2013 in a single tertiary hospital. Serum creatinine and cystatin C levels were also examined. Results Serum creatinine was correlated with muscle mass (P < .001), and serum cystatin C was correlated with body fat mass (P < .001) after adjusting glomerular filtration rate (GFR). After eliminating GFR, an equation to estimate total-body muscle mass was generated and coefficients were calculated in the derivation cohort. There was an agreement between muscle mass calculated by the novel equation and measured by DXA in both the derivation and validation cohort (P < .001, adjusted R2 = 0.829, β = 0.95, P < .001, adjusted R2 = 0.856, β = 1.03, respectively). Conclusion The new equation based on serum creatinine and cystatin C levels can be used to estimate total-body muscle mass. PMID:26849842

  8. Determination of Urinary Neopterin/Creatinine Ratio to Distinguish Active Tuberculosis from Latent Mycobacterium tuberculosis Infection

    PubMed Central

    Eisenhut, Michael; Hargreaves, Dougal S.; Scott, Anne; Housley, David; Walters, Andrew; Mulla, Rohinton

    2016-01-01

    Background. Biomarkers to distinguish latent from active Mycobacterium (M.) tuberculosis infection in clinical practice are lacking. The urinary neopterin/creatinine ratio can quantify the systemic interferon-gamma effect in patients with M. tuberculosis infection. Methods. In a prospective observational study, urinary neopterin levels were measured by enzyme linked immunosorbent assay in patients with active tuberculosis, in people with latent M. tuberculosis infection, and in healthy controls and the urinary neopterin/creatinine ratio was calculated. Results. We included a total of 44 patients with M. tuberculosis infection and nine controls. 12 patients had active tuberculosis (8 of them culture-confirmed). The median age was 15 years (range 4.5 to 49). Median urinary neopterin/creatinine ratio in patients with active tuberculosis was 374.1 micromol/mol (129.0 to 1072.3), in patients with latent M. tuberculosis infection it was 142.1 (28.0 to 384.1), and in controls it was 146.0 (40.3 to 200.0), with significantly higher levels in patients with active tuberculosis (p < 0.01). The receiver operating characteristics curve had an area under the curve of 0.84 (95% CI 0.70 to 0.97) (p < 0.01). Conclusions. Urinary neopterin/creatinine ratios are significantly higher in patients with active tuberculosis compared to patients with latent infection and may be a significant predictor of active tuberculosis in patients with M. tuberculosis infection. PMID:27433370

  9. 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

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

    PubMed Central

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

    2012-01-01

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

  11. [EXPERIENCE OF USE OF BLEMAREN® IN THE TREATMENT OF PATIENTS IN URIC ACID AND CALCIUM OXALATE UROLITHIASIS].

    PubMed

    Konstantinova, O V; Yanenko, E K

    2015-01-01

    154 patients with urolithiasis were under outpatient observation for 2-8 years. Among them there were 76 women and 78 men aged 21-66 years, of which 46 patients with uric acid urolithiasis, and 88--with calcium oxalate urolithiasis. Treatment of patients was carried out systematically, depending on their condition. Indications for the application of Blemaren® included the presence of uric acid stones, uric acid and/or oxalate crystalluria. The duration of treatment was 6.1 months. The dosage of the drug varied from 6 to 18 g per day and was selected individually, depending on the purpose of the appointment of Blemaren®. Reduction of the urine pH to 6.2- 6.8-7.2 was the criterion for properly selected dose. To dissolve uric acid stones in the presence of hyperuricemia and/or hyperuricuria, Blemaren® was administered in combination with allopurinol at a dose of 0.1 g 3-4 times a day. Besides pharmacotherapy, treatment included diet therapy. It was found that the morning urine pH in urate urolithiasis is sustainable and has a range of 5.0-6.0, in 80.4% of cases--range of 5.0-5.5. In calcium oxalate urolithiasis this parameter is also stable and has a range of 5.0-6.7, in 82.9% of cases--range of 5.5-6.0. Optimal urine pH to eliminate uric acid and oxalate crystalluria in patients with uric acid and calcium oxalate urolithiasis is the interval of 6.2-6.4. It was shown that Blemaren® is a highly effective agent for treatment and prevention of uric acid and calcium oxalate crystalluria in calcium oxalate and uric acid urolithiasis. Further, its effectiveness in dissolving of uric acid stones in the absence of an infectious inflammatory process is 82.3%. PMID:26859932

  12. Timely Diagnosis of Acute Kidney Injury Using Kinetic eGFR and the Creatinine Excretion to Production Ratio, E/eG - Creatinine Can Be Useful!

    PubMed

    Endre, Zoltán H; Pianta, Timothy J; Pickering, John W

    2016-01-01

    Post transplant repeated measurements of urine volume and serum creatinine (sCr) are used to assess kidney function. Under non-steady state conditions, repeated measurement of sCr allows calculation of the kinetic estimated GFR (KeGFR). Additional measurement of urinary creatinine allows the calculation of the creatinine excretion to (estimated) production ratio (E/eG). We hypothesized that post-transplant KeGFR and E/eG would predict delayed graft function (DGF), as early as 4 h and outperform a validated clinical model at 12 h. This was a retrospective analysis of prospectively acquired data in a study of 56 recipients of deceased-donor kidney transplant. We assessed predictive performance with the area under the receiver operator characteristic curve (AUC) and the added value to a clinical model with integrated discrimination improvement analysis. At 4 h, the AUC for E/eG was 0.87 (95% CI 0.77-0.96) and for KeGFR 0.69 (95% CI 0.56-0.83). Both E/eG and KeGFR improved the risk prediction of a clinical model for DGF by 32 and 18%, and for non-DGF by 17 and 10%, respectively. While E/eG had better predictive performance of DGF than KeGFR, KeGFR might also facilitate perioperative management including drug dosing after kidney transplantation. Together these measurements may facilitate the possibility of conducting trials of early intervention to ameliorate the adverse effects of ischaemia-reperfusion injury on long-term DGF. PMID:26950884

  13. 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

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

    ERIC Educational Resources Information Center

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

    2010-01-01

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

  15. Uric acid in the early risk stratification of ST-elevation myocardial infarction.

    PubMed

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

    2012-02-01

    Controversy still exists about uric acid as a potential prognostic risk factor for outcomes in patients with acute myocardial infarction. We prospectively assessed, in 856 patients with ST-elevation myocardial infarction (STMI) consecutively admitted to our Intensive Cardiac Care Unit after primary percutaneous coronary intervention (PCI) whether uric acid (UA) levels are associated with in-hospital mortality and complications. Killip classes III-IV were more frequent in the 3° UA tertile that was associated with the highest values of peak Tn I (p = 0.005), NT-proBNP (p < 0.001), and fibrinogen (p = 0.036). Uric acid was associated with mortality (crude OR: 1.24; 95% CI 1.03-1.51; p = 0.025), but, when adjusted for Tn I and renal failure (as inferred by eGFR <60 ml/min/1.73 m(2)), uric acid lost its statistical significance, while Tn I (100 pg/ml step OR: 1.002; 95% CI 1.000-1.003; p = 0.007) and renal failure (OR 9.16; 95% CI 3.60-23.32; p < 0.001) were independent predictors for in-ICCU mortality. Uric acid remained as independent predictor for in-ICCU complications (1 mg/dl step OR: 1.11; 95% CI 1.01-1.21; p = 0.030) together with admission glycemia (1 g/dl step OR: 1.50; 95% CI 1.19-1.91; p < 0.001) and renal failure (OR: 1.46; 95% CI 0.99-2.16; p < 0.001). In STEMI patients submitted to PCI, increased uric acid levels identify a subgroup more prone to in-ICCU complications, probably because hyperuricemia stems from several complex mechanisms ranging from pre-existing risk factors to the degree of myocardial ischemia (as indicated by Killip class, ejection fraction) and to the acute metabolic response (as inferred by glucose levels). Hyperuricemia is not independently associated with early mortality when adjusted for renal function and the degree of myocardial damage.

  16. Mathematical modeling of urea transport in the kidney.

    PubMed

    Layton, Anita T

    2014-01-01

    Mathematical modeling techniques have been useful in providing insights into biological systems, including the kidney. This article considers some of the mathematical models that concern urea transport in the kidney. Modeling simulations have been conducted to investigate, in the context of urea cycling and urine concentration, the effects of hypothetical active urea secretion into pars recta. Simulation results suggest that active urea secretion induces a "urea-selective" improvement in urine concentrating ability. Mathematical models have also been built to study the implications of the highly structured organization of tubules and vessels in the renal medulla on urea sequestration and cycling. The goal of this article is to show how physiological problems can be formulated and studied mathematically, and how such models may provide insights into renal functions.

  17. 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

  18. Haematology and blood chemistry values for several flamingo species.

    PubMed

    Peinado, V I; Polo, F J; Viscor, G; Palomeque, J

    1992-01-01

    Reference values for some haematological and plasma chemical values in four species of clinically normal adult flamingos were established for use in avian medicine. The following variables were studied in rosy, greater, Chilean and lesser flamingos: haematocrit, haemoglobin concentration, erythrocyte and leucocyte counts, haematimetric indices, erythrocyte dimensions, glucose, urea, uric acid, cholesterol, creatinine, total bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine, phosphokinase, lactic dehydrogenase, total phosphorus, chloride, total plasma protein, albumin, globulins, albumin-globulin ratio, sodium, potassium, calcium, magnesium and osmolality.

  19. 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

  20. Urea synthesis in rats fed diet containing kidney beans.

    PubMed

    Scislowski, P W; Grant, G; Harris, I; Pickard, K; Pusztai, A

    1992-10-01

    When rats were fed a diet containing kidney bean (Phaesolus vulgaris) urea excretion was increased 3-5 fold. Isolated liver mitochondria from rats fed the kidney bean diet produced 40% more citrulline in the presence of arginine than mitochondria isolated from control rats. Mitochondrial activities of urea cycle enzymes and N-acetylglutamate synthetase were similar in animals fed diets containing kidney bean or lactalbumin. The possible mechanisms causing acute urea production in rats fed with kidney bean are discussed.

  1. Urea synthesis in rats fed diet containing kidney beans.

    PubMed

    Scislowski, P W; Grant, G; Harris, I; Pickard, K; Pusztai, A

    1992-10-01

    When rats were fed a diet containing kidney bean (Phaesolus vulgaris) urea excretion was increased 3-5 fold. Isolated liver mitochondria from rats fed the kidney bean diet produced 40% more citrulline in the presence of arginine than mitochondria isolated from control rats. Mitochondrial activities of urea cycle enzymes and N-acetylglutamate synthetase were similar in animals fed diets containing kidney bean or lactalbumin. The possible mechanisms causing acute urea production in rats fed with kidney bean are discussed. PMID:1445392

  2. The electrophoresis of transferrins in urea/polyacrylamide gels.

    PubMed Central

    Evans, R W; Williams, J

    1980-01-01

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

  3. Dietary nitrogen reduction enhances urea transport across goat rumen epithelium.

    PubMed

    Muscher, A S; Schröder, B; Breves, G; Huber, K

    2010-10-01

    Ruminants are very capable of adapting their N homeostasis to a reduced dietary N intake. However, the limits of this physiological adaptation are still unknown. The aim of the present study was to determine the quantity of dietary N intake at which the needs of the animal are still satisfied. A study was performed in young White Saanen goats under conditions of dietary N reduction. Different semisynthetic diets with 19 to 7% CP were fed. Urea transport rates across the rumen epithelium from the blood into the ruminal fluid were quantified by Ussing chamber experiments. Reduced N intake increased urea transport rates across the mucosa, which could be inhibited by phloretin. The role of parietal urease in driving urea transfer across the epithelium was negligible because its activity was inhibited by antibiotics during in vitro incubations of the epithelium. Concentrations of ammonia in the ruminal fluid were decreased by reducing dietary N intake, accompanied by diminished urease activity at the smallest dietary N intake. Over the range of plasma urea concentrations observed in the different feeding groups, salivary urea concentrations were 73% of plasma urea concentrations. By plotting plasma urea concentrations against serosal to mucosal urea flux rates, a threshold at 1.75 mmol of urea/L of plasma could be assessed, below which urea flux was strongly increased. This indicates that rumen urea transfer could be stimulated by decreased plasma urea concentrations via unknown mechanisms. The physiological relevance of this adaptation of the rumen epithelium is that it is considered a central mechanism in the N homeostasis of growing goats under reduced N intake.

  4. Urea hydrolysis and calcium carbonate reaction fronts

    NASA Astrophysics Data System (ADS)

    Fox, D. T.; Redden, G. D.; Henriksen, J.; Fujita, Y.; Guo, L.; Huang, H.

    2010-12-01

    The mobility of toxic or radioactive metal contaminants in subsurface environments can be reduced by the formation of mineral precipitates that form co-precipitates with the contaminants or that isolate them from the mobile fluid phase. An engineering challenge is to control the spatial distribution of precipitation reactions with respect to: 1) the location of a contaminant, and 2) where reactants are introduced into the subsurface. One strategy being explored for immobilizing contaminants, such as Sr-90, involves stimulating mineral precipitation by forming carbonate ions and hydroxide via the in situ, microbially mediated hydrolysis of urea. A series of column experiments have been conducted to explore how the construction or design of such an in situ reactant production strategy can affect the temporal and spatial distribution of calcium carbonate precipitation, and how the distribution is coupled to changes in permeability. The columns were constructed with silica gel as the porous media. An interval midway through the column contained an adsorbed urease enzyme in order to simulate a biologically active zone. A series of influent solutions were injected to characterize hydraulic properties of the column (e.g., bromide tracer), profiles of chemical conditions and reaction products as the enzyme catalyzes urea hydrolysis (e.g., pH, ammonia, urea), and changes that occur due to CaCO3 precipitation with the introduction of a calcium+urea solutions. In one experiment, hydraulic conductivity was reduced as precipitate accumulated in a layer within the column that had a higher fraction of fine grained silica gel. Subsequent reduction of permeability and flow (for a constant head condition) resulted in displacement of the hydrolysis and precipitation reaction profiles upstream. In another experiment, which lacked the physical heterogeneity (fine grained layer), the precipitation reaction did not result in loss of permeability or flow velocity and the reaction profile

  5. Functional Nanomaterials from Bis-urea Macrocycles

    NASA Astrophysics Data System (ADS)

    Dawn, Sandipan

    Self-assembly of bis-urea macrocycles usually give tubular crystals with nano-sized channels that we use as molecular container. These molecular containers alter the reactivity, stability, and chemical behavior of the reactants entrapped within them. This dissertation is focused on bulk synthesis, material characterization and applications of a self-assembled tubular molecular container. This crystalline straw-like container is developed from cyclic bis-urea macrocycles containing two C-shaped phenylethynylene units and two urea groups. These macrocycles afford a large open channel with a diameter of ˜9 A and it can accommodate larger solid guests such as coumarin and its methylated derivatives, stilbenes, acenaphthylene and styrenes. We developed the method to introduce these solid guests into the channel from its solution. We characterized the tubular host as well as different host*guest complexes by solid-state techniques including PXRD, CP MAS 13C NMR, fluorescence and UV-vis spectroscopy. These guests usually undergo non selective photoreaction in solid-state with very low percent conversion and produce different photodimers and/or isomers. Within our molecular container, a number of guests showed photo-dimerization with amazing selectivity and enhanced conversion in the solid-state. We also performed molecular modeling studies to find out the reason behind this unprecedented selectivity. We found the orientation of the guest molecules inside the channel as well as the stability of the photoproducts within the confinement determines the outcome of the reactions. We also developed a 5,5'-bipyridine containing bis-urea macrocycle and formed its complexes with metals. These complexes have potential to further assemble through dative bonds, hydrogen bonding and aryl stacking interactions to afford metal organic framework (MOF). We found the Ag complex forms oligomers and polymers. In the polymer structure it forms infinite chains comprised of "box" like unit cell

  6. Urea formaldehyde foam: a dangerous insulation

    SciTech Connect

    Keough, C.

    1980-12-01

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

  7. Evolution of urea transporters in vertebrates: adaptation to urea's multiple roles and metabolic sources.

    PubMed

    LeMoine, Christophe M R; Walsh, Patrick J

    2015-06-01

    In the two decades since the first cloning of the mammalian kidney urea transporter (UT-A), UT genes have been identified in a plethora of organisms, ranging from single-celled bacteria to metazoans. In this review, focusing mainly on vertebrates, we first reiterate the multiple catabolic and anabolic pathways that produce urea, then we reconstruct the phylogenetic history of UTs, and finally we examine the tissue distribution of UTs in selected vertebrate species. Our analysis reveals that from an ancestral UT, three homologues evolved in piscine lineages (UT-A, UT-C and UT-D), followed by a subsequent reduction to a single UT-A in lobe-finned fish and amphibians. A later internal tandem duplication of UT-A occurred in the amniote lineage (UT-A1), followed by a second tandem duplication in mammals to give rise to UT-B. While the expected UT expression is evident in excretory and osmoregulatory tissues in ureotelic taxa, UTs are also expressed ubiquitously in non-ureotelic taxa, and in tissues without a complete ornithine-urea cycle (OUC). We posit that non-OUC production of urea from arginine by arginase, an important pathway to generate ornithine for synthesis of molecules such as polyamines for highly proliferative tissues (e.g. testis, embryos), and neurotransmitters such as glutamate for neural tissues, is an important evolutionary driving force for the expression of UTs in these taxa and tissues.

  8. Serum uric acid concentrations and SLC2A9 genetic variation in Hispanic children: the Viva La Familia Study1234

    PubMed Central

    Voruganti, V Saroja; Laston, Sandra; Haack, Karin; Mehta, Nitesh R; Cole, Shelley A; Butte, Nancy F; Comuzzie, Anthony G

    2015-01-01

    Background: 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 is not known whether the association of serum uric acid with SLC2A9 polymorphisms manifests in children. Objective: The aim was to investigate whether variation in serum uric acid is under genetic influence and whether the association with SLC2A9 polymorphisms generalizes to Hispanic children of the Viva La Familia Study. Design: We conducted a genomewide association study with 1.1 million genetic markers in 815 children. Results: We found serum uric acid to be significantly heritable [h2 ± SD = 0.45 ± 0.08, P = 5.8 × 10−11] and associated with SLC2A9 variants (P values between 10−16 and 10−7). Several of the significantly associated polymorphisms were previously identified in studies in adults. We also found positive genetic correlations between serum uric acid and BMI z score (ρG = 0.45, P = 0.002), percentage of body fat (ρG = 0.28, P = 0.04), fat mass (ρG = 0.34, P = 0.02), waist circumference (ρG = 0.42, P = 0.003), and waist-to-height ratio (ρG = 0.46, P = 0.001). Conclusions: Our results show that variation in serum uric acid in Hispanic children is under considerable genetic influence and is associated with obesity-related phenotypes. As in adults, genetic variation in SLC2A9 is associated with serum uric acid concentrations, an important biomarker of renal and cardiovascular disease risk, in Hispanic children. PMID:25833971

  9. Effect of trimethoprim on serum creatinine in healthy and chronic renal failure volunteers.

    PubMed

    Myre, S A; McCann, J; First, M R; Cluxton, R J

    1987-06-01

    The effect of trimethoprim (TMP) on serum creatinine concentration (SCr) was studied in 10 healthy (H) subjects and nine subjects with chronic renal failure (CRF). Each volunteer was given TMP 100 mg perorally every 12 h for 10 days followed by a 7-day washout period. SCr was measured colorimetrically immediately before the study (baseline), on day 10 of TMP, and 7 days after TMP had been discontinued. SCr increased an average of 14.8% from baseline during TMP administration in the H volunteers, but this increase was not statistically significant. During TMP administration to the CRF volunteers, a pronounced elevation (34.6%) of mean SCr from baseline was observed (p less than 0.05). SCr returned to baseline values in both groups following the 7-day washout period. These results are consistent with the hypothesis that TMP competitively inhibits the renal tubular secretion of creatinine. PMID:3617154

  10. Serum amylase determinations and amylase to creatinine clearance ratios in patients with chronic renal insufficiency.

    PubMed

    Tedesco, F J; Harter, H R; Alpers, D H

    1976-10-01

    Patients with severe chronic renal failure may have significant hyperamylasemia in the absence of clinical symptoms or signs of acute pancreatitis. Amylase to creatinine clearance (CA/CC) ratios were usually elevated in patients with chronic renal failure and were not helpful in evaluating the possibility of acute pancreatitis. The mean amylase to creatinine clearance ratio for the controls with normal renal function was 1.24 +/- 0.13. In patients with chronic renal failure, it was 3.17 +/- 0.42 (P less than 0.001). Serum amylase isoenzyme patterns revealed no difference in salivary to pancreatic isoenzyme ratios between normals (1.04 +/- 0.12) and patients with severe renal insufficiency without evidence of pancreatic disease (1.07 +/- 0.13). The isoenzymes were helpful in excluding the diagnosis of pancreatic in 1 renal failure patient whose hyperamylasemia was primarily salivary in origin and in confirming the diagnosis in another who had only a pancreatic band.

  11. Role of trypsin/creatinine clearance ratio in the differential diagnosis of chronic pancreatic disease.

    PubMed

    Farini, R; Fabris, C; del Favero, G; Bonvicini, P; de' Best, T; Piccoli, A; Baccaglini, U; Plebani, M; Pedrazzoli, S; Kind, R; Ceriotti, G; Naccarato, R

    1981-08-01

    Trypsin/creatinine clearance ratio--a recently proposed screening test for pancreatic cancer--was assessed in 45 subjects (17 control subjects, 15 patients with pancreatic cancer, and 13 with chronic pancreatitis). A statistically significant increase of the ratio was detected not only in pancreatic cancer, but also in chronic calcifying pancreatitis. Thus, the previously reported clinical usefulness of the test in pancreatic cancer diagnosis was not substantiated by the present data. Although not fully investigated as yet, reasons for an abnormal ratio are probably independent of the neoplastic or inflammatory nature of the pancreatic disease. Science renal enzyme excretion (alpha-glucosidase, gamma-glutamyltranspeptidase, leucine aminopeptidase) was not found to be invariably elevated when trypsin/creatinine clearance ratio was increased, tubular damage cannot be assumed as constituting the only reason for an altered clearance ratio.

  12. Trypsin/creatinine clearance ratio and serum immunoreactive trypsin in digestive and pancreatic diseases.

    PubMed

    Del Favero, G; Fabris, C; Bonvicini, P; Piccoli, A; Baccaglini, U; Pedrazzoli, S; Burlina, A; Naccarato, R

    1985-01-01

    The behavior of trypsin/creatinine clearance ratio (Ctr/Ccr) and serum immunoreactive trypsin (IRT) was evaluated in a total of 168 subjects with pancreatic cancer, chronic pancreatitis and non-pancreatic digestive diseases. Amylase/creatinine clearance ratio (Cam/Ccr) and serum amylase levels were also evaluated in order to establish their possible relationship with Ctr/Ccr and IRT values. Elevated Ctr/Ccr and IRT values were observed in several patients with pancreatic cancer and chronic pancreatitis. Abnormal IRT and Ctr/Ccr values were found in 28.2 and 4% of non-pancreatic digestive diseases, respectively. IRT and amylase serum levels showed consensual modifications, while Ctr/Ccr showed a behavior different from that of Cam/Ccr. Liver damage seems to play a role in increasing serum IRT levels of patients without pancreatic involvement, while the increased Ctr/Ccr seems to depend on other factors, for instance renal tubular dysfunction.

  13. Serum creatinine level, a surrogate of muscle mass, predicts mortality in critically ill patients

    PubMed Central

    Thongprayoon, Charat; Cheungpasitporn, Wisit

    2016-01-01

    Serum creatinine (SCr) has been widely used to estimate glomerular filtration rate (GFR). Creatinine generation could be reduced in the setting of low skeletal muscle mass. Thus, SCr has also been used as a surrogate of muscle mass. Low muscle mass is associated with reduced survival in hospitalized patients, especially in the intensive care unit (ICU) settings. Recently, studies have demonstrated high mortality in ICU patients with low admission SCr levels, reflecting that low muscle mass or malnutrition, are associated with increased mortality. However, SCr levels can also be influenced by multiple GFR- and non-GFR-related factors including age, diet, exercise, stress, pregnancy, and kidney disease. Imaging techniques, such as computed tomography (CT) and ultrasound, have recently been studied for muscle mass assessment and demonstrated promising data. This article aims to present the perspectives of the uses of SCr and other methods for prediction of muscle mass and outcomes of ICU patients. PMID:27162688

  14. [Two cases of uric acid stones unsuccessfully dissociated by oral chemolysis].

    PubMed

    Funahashi, Makoto; Yamada, Tetsuo; Murayama, Tetsuo

    2006-01-01

    We report two patients with renal uric acid (UA) stones in whom chemolysis by oral administration of alkaline citrate and allopurinol was unsuccessful. The stone in a 58-year old female did not dissolve because her urinary pH remained low throughout the day after alkaline citrate administration. The stone in a 50-year old man did not dissolve because his urinary pH was 5.5-6.0 after alkaline citrate administration. Alkalization of the urine helps reduce the stone size and the calcification of the stone. Extracorporeal shockwave lithotripsy was performed and the stone composition showed mixed calcium oxalate and calcium phosphate. The indication of oral chemolysis of uric acid stones is discussed.

  15. Mid-gestational serum uric acid concentration effect on neonate birth weight and insulin resistance in pregnant women

    PubMed Central

    Nasri, Khadijeh; Razavi, Maryamsadat; Rezvanfar, Mohammad Reza; Mashhadi, Esmat; Chehrei, Ali; Mohammadbeigi, Abolfazl

    2015-01-01

    Objective To investigate the relationship between mid-gestational serum uric acid and birth weight in diabetic pregnant women with or without insulin resistance. Methods: In a prospective cohort study, fasting uric acid, blood glucose, and serum insulin were measured in 247 pregnant women between 20-22 weeks of gestational period. Insulin resistance was estimated using the homeostasis model assessment-insulin resistance (HOMA-IR). Stratification analysis and independent t-test was used to assess the association between uric acid and birth weights regarding to insulin resistance. Results: The means of the mid-gestational serum uric acid concentrations were not significantly different in women with and without insulin resistance. But stratification analysis showed that there was a significant difference between uric acid concentration and macrosomic birth in diabetic women without insulin resistance. Conclusions: Higher mid – gestation serum uric acid concentration, even if it does not exceed the normal range, is accompanied by lower birth weight only in non-insulin resistance women. Insulin resistance could have a negative confounding effect on hyperuriemia and birth weight. PMID:25810959

  16. Elevated serum creatinine and low albumin are associated with poor outcomes in patients with liposarcoma.

    PubMed

    Panotopoulos, Joannis; Posch, Florian; Funovics, Philipp T; Willegger, Madeleine; Scharrer, Anke; Lamm, Wolfgang; Brodowicz, Thomas; Windhager, Reinhard; Ay, Cihan

    2016-03-01

    Low serum albumin levels and impaired kidney function have been associated with decreased survival in patients with a variety of cancer types. In a retrospective cohort study, we analyzed 84 patients with liposarcoma treated at from May 1994 to October 2011. Uni- and multivariable Cox proportional hazard models and competing risk analyses were performed to evaluate the association between putative biomarkers with disease-specific and overall survival. The median age of the study population was 51.7 (range 19.6-83.8) years. In multivariable analysis adjusted for AJCC tumor stage, serum creatinine was highly associated with disease-specific survival (Subdistribution Hazard ratio (SHR) per 1 mg/dl increase = 2.94; 95%CI 1.39-6.23; p = 0.005). High albumin was associated with improved overall and disease-specific survival (Hazard Ratio (HR) per 10 units increase = 0.50; 95%CI 0.26-0.95; p = 0.033 and SHR = 0.64; 95%CI 0.42-1.00; p = 0.049). The serum albumin-creatinine-ratio emerged to be associated with both overall and disease-specific survival after adjusting for AJCC tumor stage (HR = 0.95; 95%CI 0.92-0.99; p = 0.011 and SHR = 0.96; 95%CI 0.93-0.99; p = 0.08). Our study provides evidence for a tumor-stage-independent association between higher creatinine and lower albumin with worse disease-specific survival. Low albumin and a high albumin-creatinine-ratio independently predict poor overall survival. Our work identified novel prognostic biomarkers for prognosis of patients with liposarcoma.

  17. Amylase-creatinine clearance ratio. A simple test to predict gentamicin nephrotoxicity.

    PubMed

    Aderka, D; Tene, M; Graff, E; Levo, Y

    1988-05-01

    The initial target of aminoglycoside nephrotoxicity is the proximal tubule. Yet, no simple test is available to predict such toxicity. Taking advantage of the fact that amylase is filtered in the glomerulus and reabsorbed by the proximal tubules, we prospectively examined in 23 patients if changes in renal amylase creatinine clearance ratio (ACCR) can predict gentamicin nephrotoxicity. Eighteen of these patients had an initial creatinine clearance (rCcr) above 30 mL/min. Eleven of them (group A) had an ACCR above 3.5% (control 3% +/- 1.03%) and all exhibited an average reduction of 32.2% +/- 11.6% in rCcr following one week of gentamicin therapy. In contrast, only one of seven patients (group B) with an initial ACCR below 3.5% had a reduction, albeit transient, in rCcr. During gentamicin therapy, group A patients had a further increase in ACCR which was proportional to the reduction observed in rCcr (r = -.54). Our preliminary data suggest that ACCR may prove a simple and possibly a reliable predictor of kidney function deterioration during gentamicin therapy in patients with rCcr above 30 mL/min: patients with pretherapy ACCR above 3.5% may exhibit a deterioration in the creatinine clearance during the first week of therapy. For patients with pretherapy renal failure (rCcr less than 30 mL/min) the creatinine levels (but not the ACCR) seem to retain their significance in predicting and monitoring further renal function deterioration during aminoglycoside therapy.

  18. Reference intervals for serum cystatin C and serum creatinine in adults.

    PubMed

    Erlandsen, E J; Randers, E; Kristensen, J H

    1998-06-01

    The aim of this study was to establish reference intervals for cerum cystatin C and serum creatinine in adults. Blood samples were collected from 270 healthy blood donors (135 men and 135 women between 20 and 65 years old with 15 men and 15 women in each five-year-interval). Serum cystatin C was analyzed using an automated particle-enhanced immunoassay (DAKO Cystatin C PET kit) on the Cobas Mira S analyzer. Serum creatinine was analyzed using the Vitros Creatinine Slide, an enzymatic method on the Vitros 950 chemistry analyzer. The calculated reference intervals for serum cystatin C were 0.62-1.15 mg/l in women (median 0.84 mg/l, range 0.56-1.29 mg/l) and 0.51-1.25 mg/l in men (median 0.87 mg/l, range 0.42-1.39 mg/l). The Mann-Whithey U-test revealed no gender-related difference for cystatin C (p = 0.48). A common reference interval in women and men was calculated to be 0.54-1.21 mg/l (median 0.85 mg/l, range 0.42-1.39 mg/l). The non-parametric reference interval for serum creatinine was 57-95 mumol/l in women (median 72 mumol/l, range 44-105 mumol/l) and 69-111 mumol/l in men (median 89 mumol/l, range 58-123 mumol/l).

  19. Amylase-creatinine clearance ratio. A simple test to predict gentamicin nephrotoxicity.

    PubMed

    Aderka, D; Tene, M; Graff, E; Levo, Y

    1988-05-01

    The initial target of aminoglycoside nephrotoxicity is the proximal tubule. Yet, no simple test is available to predict such toxicity. Taking advantage of the fact that amylase is filtered in the glomerulus and reabsorbed by the proximal tubules, we prospectively examined in 23 patients if changes in renal amylase creatinine clearance ratio (ACCR) can predict gentamicin nephrotoxicity. Eighteen of these patients had an initial creatinine clearance (rCcr) above 30 mL/min. Eleven of them (group A) had an ACCR above 3.5% (control 3% +/- 1.03%) and all exhibited an average reduction of 32.2% +/- 11.6% in rCcr following one week of gentamicin therapy. In contrast, only one of seven patients (group B) with an initial ACCR below 3.5% had a reduction, albeit transient, in rCcr. During gentamicin therapy, group A patients had a further increase in ACCR which was proportional to the reduction observed in rCcr (r = -.54). Our preliminary data suggest that ACCR may prove a simple and possibly a reliable predictor of kidney function deterioration during gentamicin therapy in patients with rCcr above 30 mL/min: patients with pretherapy ACCR above 3.5% may exhibit a deterioration in the creatinine clearance during the first week of therapy. For patients with pretherapy renal failure (rCcr less than 30 mL/min) the creatinine levels (but not the ACCR) seem to retain their significance in predicting and monitoring further renal function deterioration during aminoglycoside therapy. PMID:2452611

  20. Uric acid plasma level and urine pH in rats treated with ambroxol.

    PubMed

    Drewa, Tomasz; Wolski, Zbigniew; Gruszka, Marzena; Misterek, Bartosz; Lysik, Joanna

    2007-01-01

    It was a chance discovery that ambroxol parenteral administration led to urinary bladder stone formation in rats. This study was undertaken to examine the serum uric acid levels and urine pH in rats after ambroxol parenteral treatment. Ambroxol influence on the uric acid level was measured in 5 rats (Rattus sp.) treated with 60 mg/kg (dissolved in injection water, sc, daily) during 2 weeks. Ambroxol influence on urine pH was examined on 45 rats divided into 3 groups. Rats from the 1st and 2nd group received 30 and 60 mg/kg/24h ambroxol, respectively. Urine was collected once daily and measured with strip kit. All values were presented as the means with standard deviations. The Student t test was used to compare the means, p < 0.05 was considered as significant. Dynamics of pH changes was measured in 4 rats treated with 60 mg/kg/24h of ambroxol. Controls received 1 mL of injection water sc. Serum uric acid level increased up to 8.7 +/- 1.0 mg/dL vs. 5.7 +/- 1.0 mg/dL in control (p < 0.002). In the 1st and 2nd group urine pH increased up to 7.5 +/- 0.5 and 7.6 +/- 0.5 vs. 6.7 +/- 0.4 (p < 0.05). Ambroxol withdrawal resulted in sequential urine pH decrease. 11 days after interruption of ambroxol therapy pH reached the starting value. Urine pH changes and possible disturbances in uric acid metabolic pathway may influence on the stone formation in rats after ambroxol parenteral treatment. The influence of ambroxol on urinary tract GAG layer and the balance between xanthine and CaOx in the urine should be checked.

  1. A Simpler Creatinine Index Can Predict Long-Term Survival in Chinese Hemodialysis Patients

    PubMed Central

    Lee, Szu-Ying; Yang, Chung-Wei; Hung, Szu-Chun; Chiang, Chih-Kang; Huang, Jenq-Wen; Hung, Kuan-Yu

    2016-01-01

    Background Low lean body mass (LBM) is an indicator of malnutrition inflammation syndrome, which is common in hemodialysis (HD) patients. The creatinine index (CI) has been validated as a reliable method to estimate LBM and evaluate the protein-energy status of HD patients. However, the traditional creatinine index formula was complex. We sought to investigate the impact of CI derived from a new simple formula on Chinese HD patient outcomes. Methods In this retrospective cohort study, we enrolled 1269 patients who initiated HD between February 1981 and February 2012 and followed them until the end of February 2013. CI was calculated using the simple creatinine kinetic model (CKM) formula. Multiple linear regression analysis and Cox regression proportional hazard analysis were used to define independent variables and compare survival between groups. Results The 1269 HD patients were categorized into 3 groups according to the tertiles of calculated CI between men and women. Each group consisted of 423 patients (50.6% men, 49.4% women). Patients in the highest sex-specific tertile of CI had longer overall survival (HR, 0.46; P 0.002). BMI did not significantly associate with survival after adjustment (HR,0.99; P 0.613). Conclusions CI derived from the simple CKM formula serves as a good parameter than BMI to predict the survival of HD patients. The formula could extend its convenient use in clinical practice for HD patients. PMID:27780214

  2. Clinical evaluation of amylase-creatinine clearance ratio and amylase isoenzyme clearance in chronic renal failure.

    PubMed

    Maeda, M; Otsuki, M; Okano, K; Yamasaki, T; Baba, S

    1981-01-01

    Amylase-creatinine clearance ratio (ACCR) and amylase isoenzyme clearance were determined simultaneously in patients with chronic renal failure. ACCR in patients with compensated renal failure (3.5 +/- 0.4%) was not significantly different from normals (2.6 +/- 0.2%), while that in patients with non-compensated renal failure (6.7 +/- 0.4%) was significantly higher than that in normals. Clearance ratio of pancreatic isoamylase (Amylase-1) relative to creatinine clearance (CAmy . 1/Ccr) in patients with both compensated (5.9 +/- 1.0%) and non-compensated (6.8 +/- 0.4%) renal failure was as high as that in patients with acute pancreatitis (6.6 +/- 0.5%). On the other hand, clearance ratio of salivary isoamylase (Amylase-3) relative to creatinine clearance (CAmy . 3/CCr) in patients with compensated renal failure (1.5 +/- 0.3%) was almost the same as that in normals (2.1 +/- 0.1%), while that in patients with non-compensated renal failure was 5.9 +/- 0.7%, which was significantly higher than that in normals. The present study revealed that elevated ACCR in patients with severely impaired renal function was due to the increase of the clearance ratio for both pancreatic and salivary amylase. These facts suggested that glomerular permeability and tubular reabsorption for pancreatic and salivary amylase might play an important role on ACCR in patients with severely impaired renal function.

  3. Mechanism of increased renal clearnace of amylase/creatinine in acute pancreatitis.

    PubMed

    Johnson, S G; Ellis, C J; Levitt, M D

    1976-11-25

    We investigated three possible causes of the increased ratio of amylase/creatinine clearance observed in acute pancreatitis. The presence of rapidly cleared isoamylase was excluded by studies of serum and urine, which demonstrated no anomalous isoamylases. In pancreatitis, the ratios (+/-1 S.E.M.) of both pancreatic isoamylase (9.2+/-0.6 per cent) and salivary isoamylase (8.6+/-1.6 per cent) were significantly (P less than 0.01) elevated over respective control values (2.4+/-0.2 and 1.8+/-0.2 per cent). Increased glomerular permeability to amylase was excluded by the demonstration of normal renal clearance of dextrans. We tested tubular reabsorption of protein by measuring the renal clearance of beta2-microglobulin, which is relatively freely filtered at the glomerulus and then avidly reabsorbed by the normal tubule. During acute pancreatitis the ratio of the renal clearance of beta2-microglobulin to that of creatinine was 1.22+/-0.52 per cent, an 80-fold increase over normal (0.015+/-0.002 per cent), with a rapid return toward normal during convalescence. Presumably, this reversible renal tubular defect also reduces amylase reabsorption and accounts for the elevated renal clearance of amylase/creatinine observed in acute pancreatitis.

  4. Clinical evaluation of amylase-creatinine clearance ratio and amylase isoenzyme clearance in chronic renal failure.

    PubMed

    Maeda, M; Otsuki, M; Okano, K; Yamasaki, T; Baba, S

    1981-01-01

    Amylase-creatinine clearance ratio (ACCR) and amylase isoenzyme clearance were determined simultaneously in patients with chronic renal failure. ACCR in patients with compensated renal failure (3.5 +/- 0.4%) was not significantly different from normals (2.6 +/- 0.2%), while that in patients with non-compensated renal failure (6.7 +/- 0.4%) was significantly higher than that in normals. Clearance ratio of pancreatic isoamylase (Amylase-1) relative to creatinine clearance (CAmy . 1/Ccr) in patients with both compensated (5.9 +/- 1.0%) and non-compensated (6.8 +/- 0.4%) renal failure was as high as that in patients with acute pancreatitis (6.6 +/- 0.5%). On the other hand, clearance ratio of salivary isoamylase (Amylase-3) relative to creatinine clearance (CAmy . 3/CCr) in patients with compensated renal failure (1.5 +/- 0.3%) was almost the same as that in normals (2.1 +/- 0.1%), while that in patients with non-compensated renal failure was 5.9 +/- 0.7%, which was significantly higher than that in normals. The present study revealed that elevated ACCR in patients with severely impaired renal function was due to the increase of the clearance ratio for both pancreatic and salivary amylase. These facts suggested that glomerular permeability and tubular reabsorption for pancreatic and salivary amylase might play an important role on ACCR in patients with severely impaired renal function. PMID:6167484

  5. 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).

  6. The Helicobacter pylori VacA toxin is a urea permease that promotes urea diffusion across epithelia

    PubMed Central

    Tombola, Francesco; Morbiato, Laura; Del Giudice, Giuseppe; Rappuoli, Rino; Zoratti, Mario; Papini, Emanuele

    2001-01-01

    Urease and the cytotoxin VacA are two major virulence factors of the human pathogen Helicobacter pylori, which is responsible for severe gastroduodenal diseases. Diffusion of urea, the substrate of urease, into the stomach is critically required for the survival of infecting H. pylori. We now show that VacA increases the transepithelial flux of urea across model epithelia by inducing an unsaturable permeation pathway. This transcellular pathway is selective, as it conducts thiourea, but not glycerol and mannitol, demonstrating that it is not due to a loosening of intercellular junctions. Experiments performed with different cell lines, grown in a nonpolarized state, confirm that VacA permeabilizes the cell plasma membrane to urea. Inhibition studies indicate that transmembrane pores formed by VacA act as passive urea transporters. Thus, their inhibition by the anion channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid significantly decreases toxin-induced urea fluxes in both polarized and nonpolarized cells. Moreover, phloretin, a well-known inhibitor of eukaryotic urea transporters, blocks VacA-mediated urea and ion transport and the toxin’s main biologic effects. These data show that VacA behaves as a low-pH activated, passive urea transporter potentially capable of permeabilizing the gastric epithelium to urea. This opens the novel possibility that in vivo VacA may favor H. pylori infectivity by optimizing urease activity. PMID:11560962

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

    NASA Astrophysics Data System (ADS)

    Banchorndhevakul, Siriwattana

    2002-08-01

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

  8. Unassisted refolding of urea unfolded rhodanese.

    PubMed

    Mendoza, J A; Rogers, E; Lorimer, G H; Horowitz, P M

    1991-07-25

    In vitro refolding after urea unfolding of the enzyme rhodanese (thiosulfate:cyanide sulfurtransferase, EC 2.8.1.1) normally requires the assistance of detergents or chaperonin proteins. No efficient, unassisted, reversible unfolding/folding transition has been demonstrated to date. The detergents or the chaperonin proteins have been proposed to stabilize folding intermediates that kinetically limit folding by aggregating. Based on this hypothesis, we have investigated a number of experimental conditions and have developed a protocol for refolding, without assistants, that gives evidence of a reversible unfolding transition and leads to greater than 80% recovery of native enzyme. In addition to low protein concentration (10 micrograms/ml), low temperatures are required to maximize refolding. Otherwise optimal conditions give less than 10% refolding at 37 degrees C, whereas at 10 degrees C the recovery approaches 80%. The unfolding/refolding phases of the transition curves are most similar in the region of the transition, and refolding yields are significantly reduced when unfolded rhodanese is diluted to low urea concentrations, rather than to concentrations near the transition region. This is consistent with the formation of "sticky" intermediates that can remain soluble close to the transition region. Apparently, nonnative structures, e.g. aggregates, can form rapidly at low denaturant concentrations, and their subsequent conversion to the native structure is slow.

  9. Modeling and Simulation for Estimating the Influence of Renal Dysfunction on the Hypouricemic Effect of Febuxostat in Hyperuricemic Patients Due to Overproduction or Underexcretion of Uric Acid.

    PubMed

    Hirai, Toshinori; Kimura, Toshimi; Echizen, Hirotoshi

    2016-01-01

    Whether renal dysfunction influences the hypouricemic effect of febuxostat, a xanthine oxidase (XO) inhibitor, in patients with hyperuricemia due to overproduction or underexcretion of uric acid (UA) remains unclear. We aimed to address this question with a modeling and simulation approach. The pharmacokinetics (PK) of febuxostat were analyzed using data from the literature. A kinetic model of UA was retrieved from a previous human study. Renal UA clearance was estimated as a function of creatinine clearance (CLcr) but non-renal UA clearance was assumed constant. A reversible inhibition model for bovine XO was adopted. Integrating these kinetic formulas, we developed a PK-pharmacodynamic (PK-PD) model for estimating the time course of the hypouricemic effect of febuxostat as a function of baseline UA level, febuxostat dose, treatment duration, body weight, and CLcr. Using the Monte Carlo simulation method, we examined the performance of the model by comparing predicted UA levels with those reported in the literature. We also modified the models for application to hyperuricemia due to UA overproduction or underexcretion. Thirty-nine data sets comprising 735 volunteers or patients were retrieved from the literature. A good correlation was observed between the hypouricemic effects of febuxostat estimated by our PK-PD model and those reported in the articles (observed) (r=0.89, p<0.001). The hypouricemic effect was estimated to be augmented in patients with renal dysfunction irrespective of the etiology of hyperuricemia. While validation in clinical studies is needed, the modeling and simulation approach may be useful for individualizing febuxostat doses in patients with various clinical characteristics.

  10. Electrochemical detection of uric acid via uricase-immobilized graphene oxide.

    PubMed

    Omar, Muhamad Nadzmi; Salleh, Abu Bakar; Lim, Hong Ngee; Ahmad Tajudin, Asilah

    2016-09-15

    Measurement of the uric acid level in the body can be improved by biosensing with respect to the accuracy, sensitivity and time consumption. This study has reported the immobilization of uricase onto graphene oxide (GO) and its function for electrochemical detection of uric acid. Through chemical modification of GO using 1-ethyl-3-(dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysulfosuccinimide (NHS) as cross-linking reagents, the enzyme activity of the immobilized uricase was much comparable to the free enzyme with 88% of the activity retained. The modified GO-uricase (GOU) was then subjected to electrocatalytic detection of uric acid (UA) via cyclic voltammetry (CV). For that reason, a glassy carbon electrode (GCE) was modified by adhering the GO along with the immobilized uricase to facilitate the redox reaction between the enzyme and the substrate. The modified GOU/GCE outperformed a bare electrode through the electrocatalytic activity with an amplified electrical signal for the detection of UA. The electrocatalytic response showed a linear dependence on the UA concentration ranging from 0.02 to 0.49 mM with a detection limit of 3.45 μM at 3σ/m. The resulting biosensor also exhibited a high selectivity towards UA in the presence of other interference as well as good reproducibility. PMID:27402177

  11. Prevention of comorbidity and acute attack of gout by uric acid lowering therapy.

    PubMed

    Joo, Kowoon; Kwon, Seong-Ryul; Lim, Mie-Jin; Jung, Kyong-Hee; Joo, Hoyeon; Park, Won

    2014-05-01

    The object of this study was to evaluate the effect of uric acid lowering therapy in reducing the new development of comorbidities and the frequency of acute attacks in gout patients. We retrospectively reviewed patients who were diagnosed to have gout with at least 3 yr of follow up. They were divided into 2 groups; 53 patients with mean serum uric acid level (sUA)<6 mg/dL and 147 patients with mean sUA≥6 mg/dL. Comorbidities of gout such as hypertension (HTN), type II diabetes mellitus (DM), chronic kidney disease, cardiovascular disease (CVD) and urolithiasis were compared in each group at baseline and at last follow-up visit. Frequency of acute gout attacks were also compared between the groups. During the mean follow up period of 7.6 yr, the yearly rate of acute attack and the new development of HTN, DM, CVD and urolithiasis was lower in the adequately treated group compared to the inadequately treated group. Tight control of uric acid decreases the incidence of acute gout attacks and comorbidities of gout such as HTN, DM, CVD and urolithiasis.

  12. The Effect of the Antioxidant Drug “U-74389G” on Creatinine Levels during Ischemia Reperfusion Injury in Rats

    PubMed Central

    Tsompos, Constantinos; Panoulis, Constantinos; Toutouzas, Konstantinos; Zografos, George; Papalois, Apostolos

    2016-01-01

    Objective The aim of this experimental study was to examine the effect of the antioxidant drug “U-74389G” on a rat model using an ischemia reperfusion protocol. The effect of U-74389G was studied biochemically by measuring mean blood creatinine levels. Materials and Methods Forty rats were used in the study. Creatinine levels were measured at 60 min of reperfusion (groups A and C) or at 120 min of reperfusion (groups B and D), where groups A and B were controls and groups C and D received U-74389G administration. Results U-74389G administration significantly decreased the predicted creatinine levels by 21.02 ± 5.06% (p = 0.0001). Reperfusion time non-significantly increased the predicted creatinine levels by 4.20 ± 6.12% (p = 0.4103). However, U-74389G administration and reperfusion time together produced a significant combined effect in decreasing the predicted creatinine levels by 11.69 ± 3.16% (p = 0.0005). Conclusion Independent of reperfusion time, U-74389G administration significantly decreased the creatinine levels in an ischemic rat model. This study demonstrates that short-term U-74389G administration improves renal function by increasing creatinine excretion. PMID:27390579

  13. 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

  14. 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.

  15. 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

  16. Underestimation of urinary biomarker-to-creatinine ratio resulting from age-related gain in muscle mass in rats.

    PubMed

    Tonomura, Yutaka; Morikawa, Yuji; Takagi, Shingo; Torii, Mikinori; Matsubara, Mitsunobu

    2013-01-01

    Recent efforts have been made to identify useful urinary biomarkers of nephrotoxicity. Furthermore, the application of urine to the other toxicities as new biomarker source has been recently expanded. Meanwhile, correction of urinary biomarker concentrations according to fluctuations in urine flow rate is required for adequate interpretation of the alteration. The urinary biomarker-to-creatinine ratio (UBCR) is widely used because of the convenience, while the urinary biomarker-excretion rate is regarded as the gold standard corrective method. Because creatinine is a catabolite in energy production in muscles, we hypothesized that altered muscle mass could affect creatinine kinetics, ultimately affecting UBCR. However, no study has examined this hypothesis. In this study, we examined the influence of muscle mass gain on UBCR, using male Sprague-Dawley rats during the growth phase, 6-12-week old. Both plasma creatinine and excretion of urinary creatinine (Ucr excretion) showed increases with muscle mass gain in rats, in which the alterations of UBCR were lowered. The renal mRNA level of the organic cation transporter-2 (Oct2), a creatinine transporter, showed an age-related increase, whereas the mRNA level of multidrug and toxin extrusions-1 (Mate1) remained constant. Multiple regression analysis showed that the increase in creatinine clearance highly contributed to the age-related increase in Ucr excretion compared to the mRNA levels of Oct2 and Mate1. This suggested that the age-related increase in Ucr excretion may be attributable to the increased transglomerular passage of creatinine. In conclusion, the results suggest that muscle mass gain can affect creatinine kinetics, leading to underestimation of UBCR. Therefore, it is important to understand the characteristics of the corrective method when using urinary biomarker, the failure of which can result in an incorrect diagnosis.

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

    PubMed Central

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

    2013-01-01

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

  18. 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... COMMISSION Solid Urea From Russia and Ukraine AGENCY: United States International Trade Commission. ACTION... orders on solid urea from Russia and Ukraine. SUMMARY: The Commission hereby gives notice that it...

  19. 40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aminoethylethylene urea methacrylamide... Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aminoethylethylene...

  20. 40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aminoethylethylene urea methacrylamide... Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aminoethylethylene...

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

    SciTech Connect

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

    2007-11-01

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

  2. 40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aminoethylethylene urea methacrylamide... Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aminoethylethylene...

  3. 40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aminoethylethylene urea methacrylamide... Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aminoethylethylene...

  4. Nonhepatic hyperammonemic encephalopathy due to undiagnosed urea cycle disorder

    PubMed Central

    Nugent, Kenneth

    2015-01-01

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

  5. 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 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 § 862.1770 Urea nitrogen test system....

  6. Urea enhances the photodynamic efficiency of methylene blue.

    PubMed

    Nuñez, 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 μM) 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 (λ = 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 (ΔG(dimer)) in aqueous solution as well as its enthalpic component in aqueous and in aqueous/urea solutions by molecular dynamics

  7. 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.

  8. Neuropsychiatric manifestations in late-onset urea cycle disorder patients.

    PubMed

    Serrano, Mercedes; Martins, Cecilia; Pérez-Dueñas, Belén; Gómez-López, Lilian; Murgui, Empar; Fons, Carmen; García-Cazorla, Angels; Artuch, Rafael; Jara, Fernando; Arranz, José A; Häberle, Johannes; Briones, Paz; Campistol, Jaume; Pineda, Mercedes; Vilaseca, Maria A

    2010-03-01

    Inherited urea cycle disorders represent one of the most common groups of inborn errors of metabolism. Late-onset urea cycle disorders caused by partial enzyme deficiencies may present with unexpected clinical phenotypes. We report 9 patients followed up in our hospital presenting late-onset urea cycle disorders who initially manifested neuropsychiatric/neurodevelopmental symptoms (the most prevalent neuropsychiatric/neurodevelopmental diagnoses were mental retardation, attention-deficit hyperactivity disorder [ADHD], language disorder, and delirium). Generally, these clinical pictures did not benefit from pharmacological treatment. Conversely, dietary treatment improved the symptoms. Regarding biochemical data, 2 patients showed normal ammonium but high glutamine levels. This study highlights the fact that neuropsychiatric/neurodevelopmental findings are common among the initial symptomatology of late-onset urea cycle disorders. The authors recommend that unexplained or nonresponsive neuropsychiatric/neurodevelopmental symptoms appearing during childhood or adolescence be followed by a study of ammonia and amino acid plasmatic levels to rule out a urea cycle disorder.

  9. A field diagnostic test for the improvised explosive urea nitrate.

    PubMed

    Almog, Joseph; Klein, Asne; Tamiri, Tsippy; Shloosh, Yael; Abramovich-Bar, Sara

    2005-05-01

    A sensitive, specific and simple color test for the improvised explosive urea nitrate is described. It is based on the formation of a red pigment upon the reaction between urea nitrate and p-dimethylaminocinnamaldehyde (p-DMAC) under neutral conditions. Urea itself, which is the starting material for urea nitrate, does not react with p-DMAC under the same conditions. Other potential sources of false positive response e.g., common fertilizers, medications containing the urea moiety and various amines, do not produce the red pigment with p-DMAC. Exhibits collected from 10 terrorist cases have been tested with p-DMAC. The results were in full agreement with those obtained by instrumental techniques including GC/MS, XRD and IR.

  10. Utility of saliva as a sample to assess renal function and estimated glomerular filtration rate.

    PubMed

    Yajamanam, Naresh; Vinapamula, Kiranmayi S; Sivakumar, V; Bitla, Aparna R; Rao, P V L N Srinivasa

    2016-03-01

    Diagnosis of renal diseases by assessing renal parameters in saliva. Biochemical investigations using serum form important component of monitoring patients with renal disease. Utility of saliva, in diagnosis and monitoring of patients with renal disease and for calculation of estimated glomerular filtration rate (eGFR), was studied. Sixty patients with renal disease and sixty ageand sex-matched healthy controls were studied. Urea, creatinine, sodium, potassium, uric acid, calcium, and phosphorus were measured in both serum and saliva. eGFR was calculated using salivary creatinine. Data were expressed as mean ± standard deviation. Comparison and correlation between groups were assessed by Student's t-test and Pearson correlation, respectively. Bland-Altman plot, mountain plot, and intra-class correlation coefficient were used to test agreement. A P <0.05 was considered statistically significant. Statistical analysis was done using Microsoft excel spreadsheets, Medcalc Version 10.0, and SPSS version 11.5. Salivary levels of urea, creatinine, uric acid, sodium, potassium, and phosphorus were higher in patients compared to controls. Potassium and phosphorus levels were higher (P = 0.001) and creatinine, sodium, calcium, and uric acid levels were lower (P = 0.001) in saliva compared to serum in both patients and controls. Positive correlation was observed between serum and salivary urea and creatinine (P < 0.0001). eGFR values calculated from salivary creatinine showed good agreement with those calculated form serum creatinine. Salivary urea (>6 mmol/L) and creatinine (>14.6 μmol/L) and eGFR calculated from salivary creatinine can be used to identify patients with renal disease.

  11. Effects of slow-release urea and rumen-protected methionine and histidine on performance of dairy cows.

    PubMed

    Giallongo, F; Hristov, A N; Oh, J; Frederick, T; Weeks, H; Werner, J; Lapierre, H; Patton, R A; Gehman, A; Parys, C

    2015-05-01

    This experiment was conducted with the objective to investigate the effects of slow-release urea and rumen-protected (RP) Met and His supplementation of a metabolizable protein (MP)-deficient diet (according to NRC, 2001) on lactation performance of dairy cows. Sixty lactating Holstein cows were used in a 10-wk randomized complete block-design trial. Cows were fed a covariate diet for 2 wk and then assigned to one of the following treatments for an 8-wk experimental period: (1) MP-adequate diet [AMP; 107% of MP requirements, based on the National Research Council (NRC, 2001)]; (2) MP-deficient diet (DMP; 95% of MP requirements); (3) DMP supplemented with slow-release urea (DMPU); (4) DMPU supplemented with RPMet (DMPUM); and (5) DMPUM supplemented with RPHis (DMPUMH). Total-tract apparent digestibility of dry matter, organic matter, neutral detergent fiber, and crude protein, and urinary N and urea-N excretions were decreased by DMP, compared with AMP. Addition of slow-release urea to the DMP diet increased urinary urea-N excretion. Dry matter intake (DMI) and milk yield (on average 44.0±0.9kg/d) were not affected by treatments, except DMPUMH increased DMI and numerically increased milk yield, compared with DMPUM. Milk true protein concentration and yield were increased and milk fat concentration tended to be decreased by DMPUMH, compared with DMPUM. Cows gained less body weight on the DMP diet, compared with AMP. Plasma concentrations of His and Lys were not affected by treatments, whereas supplementation of RPMet increased plasma Met concentration. Plasma concentration of 3-methylhistidine was or tended to be higher for DMP compared with AMP and DMPU, respectively. Addition of RPHis to the DMPUM diet tended to increase plasma glucose and creatinine. In conclusion, feeding a 5% MP-deficient diet (according to NRC, 2001) did not decrease DMI and yields of milk and milk components, despite a reduction in nutrient digestibility. Supplementation of RPHis increased

  12. Ternary metal nitrides by the urea route

    SciTech Connect

    Gomathi, A. . E-mail: gomathi@jncasr.ac.in

    2007-05-03

    Interstitial molybdenum ternary nitrides, M {sub n}Mo{sub 3}N (M = Fe and Co, n = 3; M = Ni, n = 2), can be obtained by heating the molybdate precursors, FeMoO{sub 4}, CoMoO{sub 4} and NiMoO{sub 4} with urea in the 1:12 molar ratio in the 900-1000 deg. C range. Fe{sub 3}Mo{sub 3}N and Co{sub 3}Mo{sub 3}N are obtained in pure form. The nickel nitride has the composition Ni{sub 2}Mo{sub 3}N and therefore is in admixture with nickel. All the nitrides have been characterized by various physical methods.

  13. The nutritional management of urea cycle disorders.

    PubMed

    Leonard, J V

    2001-01-01

    Diet is one of the mainstays of the treatment of patients with urea cycle disorders. The protein intake should be adjusted to take account of the inborn error and its severity and the patient's age, growth rate, and individual preferences. Currently, the widely used standards for protein intake are probably more generous than necessary, particularly for those with the more severe variants. Most patients, except those with arginase deficiency, will need supplements of arginine, but the value of other supplements including citrate and carnitine is unclear. Any patient on a low-protein diet should be monitored clinically and with appropriate laboratory tests. All should have an emergency (crisis) regimen to prevent decompensation during periods of metabolic stress.

  14. 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.

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

    PubMed

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

    2015-03-01

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

  16. Uric acid induces oxidative stress and growth inhibition by activating adenosine monophosphate-activated protein kinase and extracellular signal-regulated kinase signal pathways in pancreatic β cells.

    PubMed

    Zhang, Yongneng; Yamamoto, Tetsuya; Hisatome, Ichiro; Li, Youfeng; Cheng, Weijie; Sun, Ning; Cai, Bozhi; Huang, Tianliang; Zhu, Yuzhang; Li, Zhi; Jing, Xubin; Zhou, Rui; Cheng, Jidong

    2013-08-15

    Hyperuricaemia is a disorder of purine metabolism, and is strongly associated with insulin resistance and abnormal glucose metabolism. As the producer of insulin, pancreatic β cells might be affected by elevated serum uric acid levels and contribute to the disregulated glucose metabolism. In this study, we investigated the effect of high uric acid on rat pancreatic β cell function. Under high uric acid condition, proliferation of pancreatic β cells was inhibited, production of reactive oxygen species increased, and glucose stimulated insulin secretion was also compromised. Further examination on signal transduction pathways revealed that uric acid-induced ROS is involved in the activation of adenosine monophosphate-activated protein kinase (AMPK), and extracellular signal-regulated kinase (ERK). Pharmacological inhibition of ERK activation rescued β cells from growth inhibition. More importantly, activation of ERK induced by uric acid is significantly diminished by AMPK inhibitor, indicating ERK as a downstream target of AMPK in response to high uric acid condition. We also investigated the transportation channel for uric acid into pancreatic β cells. While major urate transporter URAT1 is not expressed in β cells, organic anion transporter (OAT) inhibitor successfully blocked the activation of ERK by uric acid. Our data indicate that high uric acid levels induce oxidative damage and inhibit growth of rat pancreatic β cells by activating the AMPK and ERK signal pathways. Hyperuricemia may contribute to abnormal glucose metabolism by causing oxidative damage and function inhibition of pancreatic β cells.

  17. Loss of tubular creatinine secretion as the only sign of tubular proximal cell dysfunction in light chain proximal tubulopathy

    PubMed Central

    Stehlé, Thomas; Vignon, Marguerite; Flamant, Martin; Figueres, Marie-Lucile; Rabant, Marion; Rodenas, Anita; Noël, Laure-Hélène; Arnulf, Bertrand; Vidal-Petiot, Emmanuelle

    2016-01-01

    Abstract Light chain proximal tubulopathy (LCPT) is a rare disease, characterized by cytoplasmic inclusions of light chain (usually kappa) immunoglobulins. Clinical presentation is usually a Fanconi syndrome. The proximal tubular dysfunction can be incomplete, and exceptional cases of LCPT without any tubular dysfunction have even been described. Here, we report a case of LCPT in which the only sign of proximal tubulopathy is the absence of secretion of creatinine, as assessed by the simultaneous measurement of renal clearance of creatinine and 51CrEDTA. The loss of tubular creatinine secretion as a sign of tubular proximal cell dysfunction ought to be identified in patients with light chain proximal tubulopathy as it leads to a clinically relevant underestimation of GFR by the creatinine-derived equations. The prevalence and prognostic significance of this particular proximal tubular damage in LCPT remain to be determined. PMID:27367983

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

    PubMed

    Williamson, Lydia; New, David

    2014-09-19

    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.

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

    PubMed Central

    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

  20. Improving long term outcomes in urea cycle disorders-report from the Urea Cycle Disorders Consortium.

    PubMed

    Waisbren, Susan E; Gropman, Andrea L; Batshaw, Mark L

    2016-07-01

    The Urea Cycle Disorders Consortium (UCDC) has conducted, beginning in 2006, a longitudinal study (LS) of eight enzyme deficiencies/transporter defects associated with the urea cycle. These include N-acetylglutamate synthase deficiency (NAGSD); Carbamyl phosphate synthetase 1 deficiency (CPS1D); Ornithine transcarbamylase deficiency (OTCD); Argininosuccinate synthetase deficiency (ASSD) (Citrullinemia); Argininosuccinate lyase deficiency (ASLD) (Argininosuccinic aciduria); Arginase deficiency (ARGD, Argininemia); Hyperornithinemia, hyperammonemia, homocitrullinuria (HHH) syndrome (or mitochondrial ornithine transporter 1 deficiency [ORNT1D]); and Citrullinemia type II (mitochondrial aspartate/glutamate carrier deficiency [CITRIN]). There were 678 UCD patients enrolled in 14 sites in the U.S., Canada, and Europe at the writing of this paper. This review summarizes findings of the consortium related to outcome, focusing primarily on neuroimaging findings and neurocognitive function. Neuroimaging studies in late onset OTCD offered evidence that brain injury caused by biochemical dysregulation may impact functional neuroanatomy serving working memory processes, an important component of executive function and regulation. Additionally, there were alteration in white mater microstructure and functional connectivity at rest. Intellectual deficits in OTCD and other urea cycle disorders (UCD) vary. However, when neuropsychological deficits occur, they tend to be more prominent in motor/performance areas on both intelligence tests and other measures. In some disorders, adults performed significantly less well than younger patients. Further longitudinal follow-up will reveal whether this is due to declines throughout life or to improvements in diagnostics (especially newborn screening) and treatments in the younger generation of patients.

  1. The urea carboxylase and allophanate hydrolase activities of urea amidolyase are functionally independent.

    PubMed

    Lin, Yi; Boese, Cody J; St Maurice, Martin

    2016-10-01

    Urea amidolyase (UAL) is a multifunctional biotin-dependent enzyme that contributes to both bacterial and fungal pathogenicity by catalyzing the ATP-dependent cleavage of urea into ammonia and CO2 . UAL is comprised of two enzymatic components: urea carboxylase (UC) and allophanate hydrolase (AH). These enzyme activities are encoded on separate but proximally related genes in prokaryotes while, in most fungi, they are encoded by a single gene that produces a fusion enzyme on a single polypeptide chain. It is unclear whether the UC and AH activities are connected through substrate channeling or other forms of direct communication. Here, we use multiple biochemical approaches to demonstrate that there is no substrate channeling or interdomain/intersubunit communication between UC and AH. Neither stable nor transient interactions can be detected between prokaryotic UC and AH and the catalytic efficiencies of UC and AH are independent of one another. Furthermore, an artificial fusion of UC and AH does not significantly alter the AH enzyme activity or catalytic efficiency. These results support the surprising functional independence of AH from UC in both the prokaryotic and fungal UAL enzymes and serve as an important reminder that the evolution of multifunctional enzymes through gene fusion events does not always correlate with enhanced catalytic function.

  2. Improving long term outcomes in urea cycle disorders-report from the Urea Cycle Disorders Consortium.

    PubMed

    Waisbren, Susan E; Gropman, Andrea L; Batshaw, Mark L

    2016-07-01

    The Urea Cycle Disorders Consortium (UCDC) has conducted, beginning in 2006, a longitudinal study (LS) of eight enzyme deficiencies/transporter defects associated with the urea cycle. These include N-acetylglutamate synthase deficiency (NAGSD); Carbamyl phosphate synthetase 1 deficiency (CPS1D); Ornithine transcarbamylase deficiency (OTCD); Argininosuccinate synthetase deficiency (ASSD) (Citrullinemia); Argininosuccinate lyase deficiency (ASLD) (Argininosuccinic aciduria); Arginase deficiency (ARGD, Argininemia); Hyperornithinemia, hyperammonemia, homocitrullinuria (HHH) syndrome (or mitochondrial ornithine transporter 1 deficiency [ORNT1D]); and Citrullinemia type II (mitochondrial aspartate/glutamate carrier deficiency [CITRIN]). There were 678 UCD patients enrolled in 14 sites in the U.S., Canada, and Europe at the writing of this paper. This review summarizes findings of the consortium related to outcome, focusing primarily on neuroimaging findings and neurocognitive function. Neuroimaging studies in late onset OTCD offered evidence that brain injury caused by biochemical dysregulation may impact functional neuroanatomy serving working memory processes, an important component of executive function and regulation. Additionally, there were alteration in white mater microstructure and functional connectivity at rest. Intellectual deficits in OTCD and other urea cycle disorders (UCD) vary. However, when neuropsychological deficits occur, they tend to be more prominent in motor/performance areas on both intelligence tests and other measures. In some disorders, adults performed significantly less well than younger patients. Further longitudinal follow-up will reveal whether this is due to declines throughout life or to improvements in diagnostics (especially newborn screening) and treatments in the younger generation of patients. PMID:27215558

  3. Minor Postoperative Increases of Creatinine Are Associated with Higher Mortality and Longer Hospital Length of Stay in Surgical Patients

    PubMed Central

    Kork, Felix; Balzer, Felix; Spies, Claudia D.; Wernecke, Klaus-Dieter; Ginde, Adit A.; Jankowski, Joachim; Eltzschig, Holger K.

    2015-01-01

    Background Surgical patients frequently experience postoperative increases in creatinine levels. The authors hypothesized that even small increases in postoperative creatinine levels are associated with adverse outcomes. Methods The authors examined the association of postoperative changes from preoperative baseline creatinine with all-cause in-hospital mortality and hospital length of stay (HLOS) in a retrospective analysis of surgical patients at a single tertiary care center between January 2006 and June 2012. Results The data of 39,369 surgical patients (noncardiac surgery n = 37,345; cardiac surgery n = 2,024) were analyzed. Acute kidney injury (AKI)—by definition of the Kidney Disease: Improving Global Outcome group—was associated with a five-fold higher mortality (odds ratio [OR], 4.8; 95% CI, 4.1 to 5.7; P < 0.001) and a longer HLOS of 5 days (P < 0.001) after adjusting for age, sex, comorbidities, congestive heart failure, preoperative hemoglobin, preoperative creatinine, exposure to radiocontrast agent, type of surgery, and surgical AKI risk factors. Importantly, even minor creatinine increases (Δcreatinine 25 to 49% above baseline but < 0.3 mg/dl) not meeting AKI criteria were associated with a two-fold increased risk of death (OR, 1.7; 95% CI, 1.3 to 2.4; P < 0.001) and 2 days longer HLOS (P < 0.001). This was more pronounced in noncardiac surgery patients. Patients with minor creatinine increases had a five-fold risk of death (OR, 5.4; 95% CI, 1.5 to 20.3; P < 0.05) and a 3-day longer HLOS (P < 0.01) when undergoing noncardiac surgery. Conclusions Even minor postoperative increases in creatinine levels are associated with adverse outcomes. These results emphasize the importance to find effective therapeutic approaches to prevent or treat even mild forms of postoperative kidney dysfunction to improve surgical outcomes. PMID:26492475

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

    NASA Astrophysics Data System (ADS)

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

    2003-01-01

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

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

    PubMed

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

    2016-01-01

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

  6. 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

  7. Specific gravity and creatinine as corrections for variation in urine concentration in humans, gorillas, and woolly monkeys.

    PubMed

    White, Brent C; Jamison, Keri M; Grieb, Cassie; Lally, Drew; Luckett, Cloe; Kramer, Katie S; Phillips, Justin

    2010-12-01

    Hormones excreted in the urine are widely used to assess the physiological and psychological condition of unrestrained animals. In order to control for variation in the water concentration of urine samples, the hormone concentration is often indexed to the concentration of creatinine. Because there are several problems with using creatinine, we have investigated the efficacy of specific gravity as an alternative basis for adjusting the hormone concentration in humans, gorillas, and woolly monkeys. In an experimental manipulation of human urine hydration, ten volunteers drank a water load proportional to body weight, and provided complete urine collection and saliva samples for four consecutive 20 min intervals. From the urine, we measured cortisol (radioimmunoassay), creatinine (colorimetric assay), and specific gravity (refractometer). Only cortisol was assayed from saliva. During 80 min following water ingestion, cortisol, creatinine, and specific gravity declined as urine became diluted; however, total cortisol excretion remained constant. Only cortisol concentration indexed to specific gravity accurately reflected the consistent cortisol excretion. Specific gravity and creatinine-corrected cortisol values were highly correlated but were significantly different. Salivary cortisol provided evidence for the relative stability of serum cortisol. To determine the utility of these corrections in other primates, we compared specific gravity- and creatinine-corrected cortisol in urine samples from captive gorillas (N=16) and woolly monkeys (N=8). As with the human study, the two corrections were strongly correlated in each species, but the means were different. Specific gravity correction was superior in revealing the circadian variation in cortisol.

  8. Specific gravity as an alternative to creatinine for estimating urine concentration in captive and wild chimpanzee (Pan troglodytes) Samples.

    PubMed

    Anestis, Stephanie F; Breakey, Alicia A; Beuerlein, Melanie M; Bribiescas, Richard G

    2009-02-01

    The measurement of hormones in urine has become a widely used technique in primatology. Because urine concentration varies according to fluid intake, concentration must be measured in each sample collected, and hormone values are always expressed per unit of concentration. Traditionally, creatinine has been used as a concentration index, but some studies in humans have shown that creatinine varies among populations and even within and between individuals within a population, and that it begins to degrade after just one freeze-thaw cycle. In addition, creatinine measurement is relatively time-consuming and expensive and creates hazardous waste. In this study, we tested the hypothesis that specific gravity, or the ratio of the density of a sample to that of water, is highly correlated with creatinine measurement in urine samples collected from captive chimpanzees at the New Iberia Research Center in Louisiana and wild chimpanzees at the Ngogo study site in the Kibale National Park, Uganda. We found that specific gravity and creatinine were highly correlated in both captive (N=124) and wild (N=13) chimpanzee samples, and that specific gravity measurement was robust to actual and simulated transport conditions and repeated freeze-thaw cycles. We recommend that researchers consider specific gravity measurement as a preferable alternative to creatinine measurement in their studies of primate endocrinology.

  9. The role of the uncertainty of measurement of serum creatinine concentrations in the diagnosis of acute kidney injury.

    PubMed

    Kin Tekce, Buket; Tekce, Hikmet; Aktas, Gulali; Uyeturk, Ugur

    2016-01-01

    Uncertainty of measurement is the numeric expression of the errors associated with all measurements taken in clinical laboratories. Serum creatinine concentration is the most common diagnostic marker for acute kidney injury. The goal of this study was to determine the effect of the uncertainty of measurement of serum creatinine concentrations on the diagnosis of acute kidney injury. We calculated the uncertainty of measurement of serum creatinine according to the Nordtest Guide. Retrospectively, we identified 289 patients who were evaluated for acute kidney injury. Of the total patient pool, 233 were diagnosed with acute kidney injury using the AKIN classification scheme and then were compared using statistical analysis. We determined nine probabilities of the uncertainty of measurement of serum creatinine concentrations. There was a statistically significant difference in the number of patients diagnosed with acute kidney injury when uncertainty of measurement was taken into consideration (first probability compared to the fifth p = 0.023 and first probability compared to the ninth p = 0.012). We found that the uncertainty of measurement for serum creatinine concentrations was an important factor for correctly diagnosing acute kidney injury. In addition, based on the AKIN classification scheme, minimizing the total allowable error levels for serum creatinine concentrations is necessary for the accurate diagnosis of acute kidney injury by clinicians.

  10. 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.

  11. Determination of renal clearances of amylase/creatinine with chromogenic and enzymatic methods.

    PubMed

    Hohenwallner, W; Wimmer, E; Sommer, R

    1979-12-01

    Urinary amylase was estimated by chromogenic (amylochrome Roche) as well as enzymatic methods (SKI and Beckman: substrate starch and substrate maltotetraose respectively). Random and timed urines (24 hour collections) were analysed. Clearances of amylase gave different results dependent upon the amylase-test used and the glomerular filtration rate. Correlation between chromogenic and enzymatic methods (starch as substrate) was poor. The ratio of amylase and creatinine clearance was used to test different methods. Reference values for this ratio for the amylochrome method (N = 106) were 2.85 +/- 0.99% and for the Beckman-DS method (N = 60) 2.82 +/- 0.87%.

  12. [Ratio of amylase clearance and creatinine clearance in the diagnosis of acute pancreatitis].

    PubMed

    Haffter, D; Reichlin, B; Gyr, K

    1981-05-30

    In 21 healthy volunteers the ratio of amylase clearance and creatinine clearance (Cam/Ccr) was determined in urine collected at admission, after a 1-hour collection period and after a 2-hour collection period. The normal values were 1.8 +/- 1.6%, 1.9 +/- 2% and 2.0 +/- 1.7% respectively. They were comparable with those published by others. The reproducibility of the method was acceptable (r = 0.62). When compared with serum amylase determinations, Cam/Ccr showed neither better sensitivity in 19 patients suffering an acute episode of proven pancreatitis, nor better specificity in 19 patients with acute abdomen but no evidence of pancreatitis.

  13. Amylase/creatinine clearance ratio and tubular proteinuria in acute pancreatitis.

    PubMed

    Lankisch, P G; Wolfrum, D I; Koop, H; Winckler, K

    1979-01-01

    Amylase/creatinine clearance ratio (CAm/CCr), urinary protein concentration and urinary protein pattern were studied in 102 samples from 27 patients with acute pancreatitis and in 46 controls. Raised CAm/CCr, proteinuria and a tubular protein pattern were present in 74, 56 and 96% of the patients, respectively. However, CAm/CCr and proteinuria and CAm/CCr and tubular protein pattern were not correlated. These results do not support the suggestion that an elevated CAm/CCr in acute pancreatitis is due to generalized tubular protein reabsorption failure presenting with tubular proteinuria.

  14. Association of high-sensitivity C-reactive protein and uric acid with the metabolic syndrome components.

    PubMed

    Sah, Santosh Kumar; Khatiwada, Saroj; Pandey, Sunil; Kc, Rajendra; Das, Binod Kumar Lal; Baral, Nirmal; Lamsal, Madhab

    2016-01-01

    Metabolic syndrome (MetS) has been found to be associated with inflammatory molecules. This study was conducted among 125 MetS patients at B P Koirala Institute of Health Sciences, Dharan, Nepal to find an association of high-sensitivity C-reactive protein (hs-CRP) and serum uric acid with MetS components. Anthropometric measurements, blood pressure, medical history and blood samples were taken. Estimation of hs-CRP, serum uric acid, blood glucose, triglyceride and high density lipoprotein (HDL) cholesterol was done. hs-CRP had positive correlation with blood glucose (r = 0.2, p = 0.026) and negative with HDL cholesterol (r = -0.361, p < 0.001). Serum uric acid had positive correlation with waist circumference (r = 0.178, p = 0.047). Patients with elevated hs-CRP and uric acid had higher waist circumference (p = 0.03), diastolic BP (p = 0.002) and lower HDL cholesterol (p = 0.004) than others. Elevated hs-CRP and high uric acid were individually associated with higher odds for low HDL cholesterol (7.992; 1.785-35.774, p = 0.002) and hyperglycemia (2.471; 1.111-5.495, p = 0.029) respectively. Combined rise of hs-CRP and uric acid was associated with severity of MetS (p < 0.001) and higher odds for hyperglycemia (8.036; 2.178-29.647, p = 0.001) as compared to individual rise of hs-CRP or uric acid. The present study demonstrates that hs-CRP and serum uric acid are associated with MetS components, and the combined rise of hs-CRP and uric acid is associated with the increase in severity of MetS. PMID:27006878

  15. Diaryl Urea: A Privileged Structure in Anticancer Agents.

    PubMed

    Garuti, Laura; Roberti, Marinella; Bottegoni, Giovanni; Ferraro, Mariarosaria

    2016-01-01

    The diaryl urea is an important fragment/pharmacophore in constructing anticancer molecules due to its near-perfect binding with certain acceptors. The urea NH moiety is a favorable hydrogen bond donor, while the urea oxygen atom is regarded as an excellent acceptor. Many novel compounds have been synthesized and evaluated for their antitumor activity with the successful development of sorafenib. Moreover, this structure is used to link alkylating pharmacophores with high affinity DNA binders. In addition, the diaryl urea is present in several kinase inhibitors, such as RAF, KDR and Aurora kinases. Above all, this moiety is used in the type II inhibitors: it usually forms one or two hydrogen bonds with a conserved glutamic acid and one with the backbone amide of the aspartic acid in the DFG motif. In addition, some diaryl urea derivatives act as Hedgehog (Hh) ligands, binding and inhibiting proteins involved in the homonymous Hh signaling pathway. In this review we provide some of the methodologies adopted for the synthesis of diaryl ureas and a description of the most representative antitumor agents bearing the diaryl urea moiety, focusing on their mechanisms bound to the receptors and structure-activity relationships (SAR). An increased knowledge of these derivatives could prompt the search to find new and more potent compounds. PMID:27063259

  16. 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.

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

    PubMed

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

    2010-01-01

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

  18. 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

  19. Target analysis studies of red cell water and urea transport.

    PubMed

    Dix, J A; Ausiello, D A; Jung, C Y; Verkman, A S

    1985-12-01

    Radiation inactivation was used to determine the nature and molecular weight of water and urea transporters in the human red cell. Red cells were frozen to -50 degrees C in a cryoprotectant solution, irradiated with 1.5 MeV electrons, thawed, washed and assayed for osmotic water and urea permeability by stopped-flow light scattering. The freezing and thawing process did not affect the rates of water or urea transport or the inhibitory potency of p-chloromercuribenzenesulfonate (pCMBS) on water transport and of phloretin on urea transport. Red cell urea transport inactivated with radiation (0-4 Mrad) with a single target size of 469 +/- 36 kDa. 40 microM phloretin inhibited urea flux by approx. 50% at each radiation dose, indicating that urea transporters surviving radiation were inhibitable. Water transport did not inactivate with radiation; however, the inhibitory potency of 2.5 mM pCMBS decreased from 86 +/- 1% to 4 +/- 9% over a 0-2 Mrad dose range. These studies suggest that red cell water transport either required one or more low-molecular-weight proteins, or is lipid-mediated, and that the pCMBS-binding site which regulates water flow inactivates with radiation. These results also suggest that red cell urea transport is mediated by a specific, high-molecular-weight protein. These results do not support the hypothesis that a band 3 dimer (190 kDa) mediates red cell osmotic water and urea transport. PMID:2998469

  20. 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.

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

    PubMed

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

    2015-01-01

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

  2. Phytochemicals from Tradescantia albiflora Kunth Extracts Reduce Serum Uric Acid Levels in Oxonate-induced Rats

    PubMed Central

    Wang, Wen-Ling; Sheu, Shi-Yuan; Huang, Wen-Dar; Chuang, Ya-Ling; Tseng, Han-Chun; Hwang, Tzann-Shun; Fu, Yuan-Tsung; Kuo, Yueh-Hsiung; Yao, Chun-Hsu; Kuo, Tzong-Fu

    2016-01-01

    Background: Tradescantia albiflora (TA) Kunth (Commelinaceae) has been used for treating gout and hyperuricemia as folklore remedies in Taiwan. Therefore, it is worthwhile to study the effect of TA extracts on lowering uric acid activity. The hypouricemic effects of TA extracts on potassium oxonate (PO)-induced acute hyperuricemia were investigated for the first time. Materials and Methods: All treatments at the same volume (1 ml) were orally administered to the abdominal cavity of PO-induced hyperuricemic rats. One milliliter of TA extract in n-hexane (HE), ethyl acetate (EA), n-butanol (BuOH), and water fractions has 0.28, 0.21, 0.28, and 1.03 mg TA, respectively; and the plasma uric acid (PUA) level was measured for a consecutive 4 h after administration. Results: All four fractions' extracts derived from TA were observed to significantly reduce PUA compared with the PO group. The EA-soluble fraction (TA-EA) exhibited the best xanthine oxidase (XO) inhibitory activity. Following column chromatography, 12 phytochemicals were isolated and identified from the EA fraction. The IC50 values of isolated phytochemicals indicated that bracteanolide A (AR11) showed the remarkable XO inhibitory effect (IC50 value of 76.4 μg/ml). These findings showed that the in vivo hypouricemic effect in hyperuricemic rats was consistent with in vitro XO inhibitory activity, indicating that TA extracts and derived phytochemicals could be potential candidates as hypouricemic agents. SUMMARY Tradescantia albiflora extracts possess in vivo hypouricemic action in hyperuricemic ratsT. albiflora extracts exhibited strong inhibitory activity against xanthine oxidase (XO)Butenolide may play an important role in XO inhibitionThe extract bracteanolide A was demonstrated potent XO inhibitory activity in vitro. Abbreviations used: TA: Tradescantia albiflora, PO: potassium oxonate, HE: n-hexane, EA: ethyl acetate, BuOH: n-butanol, PUA: plasma uric acid, XO: xanthine oxidase, MeOH: methanol, IP

  3. Real-time in vivo uric acid biosensor system for biophysical monitoring of birds.

    PubMed

    Gumus, A; Lee, S; Karlsson, K; Gabrielson, R; Winkler, D W; Erickson, D

    2014-02-21

    Research on birds has long played an important role in ecological investigations, as birds are relatively easily observed, and their high metabolic rates and diurnal habits make them quite evidently responsive to changes in their environments. A mechanistic understanding of such avian responses requires a better understanding of how variation in physiological state conditions avian behavior and integrates the effects of recent environmental changes. There is a great need for sensor systems that will allow free-flying birds to interact with their environment and make unconstrained decisions about their spatial location at the same time that their physiological state is being monitored in real time. We have developed a miniature needle-based enzymatic sensor system suitable for continuous real-time amperometric monitoring of uric acid levels in unconstrained live birds. The sensor system was constructed with Pt/Ir wire and Ag/AgCl paste. Uricase enzyme was immobilized on a 0.7 mm sensing cavity of Nafion/cellulose inner membrane to minimize the influences of background interferents. The sensor response was linear from 0.05 to 0.6 mM uric acid, which spans the normal physiological range for most avian species. We developed a two-electrode potentiostat system that drives the biosensor, reads the output current, and wirelessly transmits the data. In addition to extensive characterization of the sensor and system, we also demonstrate autonomous operation of the system by collecting in vivo extracellular uric acid measurements on a domestic chicken. The results confirm our needle-type sensor system's potential for real-time monitoring of birds' physiological state. Successful application of the sensor in migratory birds could open up a new era of studying both the physiological preparation for migration and the consequences of sustained avian flight.

  4. Real-time in vivo uric acid biosensor system for biophysical monitoring of birds.

    PubMed

    Gumus, A; Lee, S; Karlsson, K; Gabrielson, R; Winkler, D W; Erickson, D

    2014-02-21

    Research on birds has long played an important role in ecological investigations, as birds are relatively easily observed, and their high metabolic rates and diurnal habits make them quite evidently responsive to changes in their environments. A mechanistic understanding of such avian responses requires a better understanding of how variation in physiological state conditions avian behavior and integrates the effects of recent environmental changes. There is a great need for sensor systems that will allow free-flying birds to interact with their environment and make unconstrained decisions about their spatial location at the same time that their physiological state is being monitored in real time. We have developed a miniature needle-based enzymatic sensor system suitable for continuous real-time amperometric monitoring of uric acid levels in unconstrained live birds. The sensor system was constructed with Pt/Ir wire and Ag/AgCl paste. Uricase enzyme was immobilized on a 0.7 mm sensing cavity of Nafion/cellulose inner membrane to minimize the influences of background interferents. The sensor response was linear from 0.05 to 0.6 mM uric acid, which spans the normal physiological range for most avian species. We developed a two-electrode potentiostat system that drives the biosensor, reads the output current, and wirelessly transmits the data. In addition to extensive characterization of the sensor and system, we also demonstrate autonomous operation of the system by collecting in vivo extracellular uric acid measurements on a domestic chicken. The results confirm our needle-type sensor system's potential for real-time monitoring of birds' physiological state. Successful application of the sensor in migratory birds could open up a new era of studying both the physiological preparation for migration and the consequences of sustained avian flight. PMID:24326318

  5. Determination of creatinine-related molecules in saliva by reversed-phase liquid chromatography with tandem mass spectrometry and the evaluation of hemodialysis in chronic kidney disease patients.

    PubMed

    Suzuki, Mayu; Furuhashi, Mitsuyoshi; Sesoko, Shogo; Kosuge, Kazuhiro; Maeda, Toshio; Todoroki, Kenichiro; Inoue, Koichi; Min, Jun Zhe; Toyo'oka, Toshimasa

    2016-03-10

    The serum concentrations of creatinine (Cre) and urea are used for the determination of the renal function. However, the use of blood is not always suitable due to the invasive, hygienic and infection problems during its sample collection and handling. In contrast, saliva is relatively clean and the samples can be quickly and noninvasively collected and easily stored. Therefore, the simultaneous determination of Arginine (Arg), creatine (Cr) and Cre in the saliva of chronic kidney disease (CKD) patients was performed by UPLC-ESI-MS/MS together with the saliva of healthy volunteers. The evaluation of hemodialysis of CKD patients was also carried out by the determinations before and after the dialysis. An HS-F5 column was used for the simultaneous determination of Arg, Cr and Cre in the saliva. These molecules were rapidly separated within 4 min and sensitively determined by the multiple reaction monitoring (MRM) of the precursor ion [M+H](+) → product ions (m/z 175.1 → 70.1 for Arg; m/z 132.0 → 44.1 for Cr; m/z 114.0 → 44.1 for Cre). The concentration of Cre in the CKD patients was higher than that in the healthy persons. The concentrations of Cre in the saliva of the patients before hemodialysis were moderately correlated with the serum Cre concentrations (R(2) = 0.661). Furthermore, the concentration in the saliva obviously decreased after hemodialysis (before 0.73 mg/dL, after 0.25 mg/dL; p < 0.02). Thus, the proposed detection method using saliva by UPLC-MS/MS is useful for the evaluation of the renal function in CKD patients. The present method offers a new option for monitoring the hemodialysis of CKD patients.

  6. Increased Serum Uric Acid Levels Blunt the Antihypertensive Efficacy of Lifestyle Modifications in Children at Cardiovascular Risk.

    PubMed

    Viazzi, Francesca; Rebora, Paola; Giussani, Marco; Orlando, Antonina; Stella, Andrea; Antolini, Laura; Valsecchi, Maria Grazia; Pontremoli, Roberto; Genovesi, Simonetta

    2016-05-01

    Primary hypertension is a growing concern in children because of the obesity epidemic largely attributable to western lifestyles. Serum uric acid is known to be influenced by dietary habits, correlates with obesity, and could represent a risk factor for hypertension. Preliminary studies in children highlighted uric acid as a potentially modifiable risk factor for the prevention and treatment of hypertension. The effect of lifestyle changes (increase of physical activity and dietary modifications) on blood pressure values, weight status, and serum uric acid levels in a cohort of 248 children referred for cardiovascular risk assessment were evaluated over a mean 1.5-year follow-up. At baseline, 48% of children were obese and 50% showed blood pressure values >90th percentile. At follow-up, a significant improvement in weight class (24% obese;P<0.0001) and blood pressure category (22% >90th percentile;P<0.0001) was found. Systolic blood pressure z-score (P<0.0001), uric acid value (P=0.0056), and puberty at baseline (P=0.0048) were independently associated with higher systolic blood pressure z-score at follow-up, whereas a negative association was observed with body mass index z-score decrease during follow-up (P=0.0033). The risk of hypertension at follow-up was associated with body mass index (P=0.0025) and systolic blood pressure (P<0.0001) z-score at baseline and inversely related to delta body mass index (P=0.0002), whereas the risk of showing hypertension ≥99th percentile was more than doubled for each baseline 1 mg/dL increase of serum uric acid (P=0.0130). Uric acid is a powerful determinant of blood pressure over time, independent of lifestyle modifications. PMID:27021006

  7. Quantum crystallographic charge density of urea

    DOE PAGESBeta

    Wall, Michael E.

    2016-06-08

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell 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 was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the datamore » is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. Lastly, the results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement.« less

  8. Quantum crystallographic charge density of urea

    PubMed Central

    Wall, Michael E.

    2016-01-01

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell 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 was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement. PMID:27437111

  9. 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

  10. 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

  11. Quantum crystallographic charge density of urea.

    PubMed

    Wall, Michael E

    2016-07-01

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell 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 was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement. PMID:27437111

  12. Quantum crystallographic charge density of urea.

    PubMed

    Wall, Michael E

    2016-07-01

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell 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 was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement.

  13. Urea as a cosurfactant in enhanced oil recovery processes

    SciTech Connect

    Stapp, P. R.; Chaney, M. B.

    1985-01-15

    A surfactant system useful for oil recovery comprising salt water, a surfactant, such as a petroleum sulfonate, and urea. Optionally, a C/sub 3/ to C/sub 8/ alcohol is additionally present as a cosurfactant.

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

    NASA Technical Reports Server (NTRS)

    Lohrmann, R.

    1972-01-01

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

  15. 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.

  16. Influence of Ficoll on urea induced denaturation of fibrinogen

    NASA Astrophysics Data System (ADS)

    Sankaranarayanan, Kamatchi; Meenakshisundaram, N.

    2016-03-01

    Ficoll is a neutral, highly branched polymer used as a molecular crowder in the study of proteins. Ficoll is also part of Ficoll-Paque used in biology laboratories to separate blood to its components (erythrocytes, leukocytes etc.,). Role of Ficoll in the urea induced denaturation of protein Fibrinogen (Fg) has been analyzed using fluorescence, circular dichroism, molecular docking and interfacial studies. Fluorescence studies show that Ficoll prevents quenching of Fg in the presence of urea. From the circular dichroism spectra, Fg shows conformational transition to random coil with urea of 6 M concentration. Ficoll helps to shift this denaturation concentration to 8 M and thus constraints by shielding Fg during the process. Molecular docking studies indicate that Ficoll interacts favorably with the protein than urea. The surface tension and shear viscosity analysis shows clearly that the protein is shielded by Ficoll.

  17. Urea determination using pH-enzyme electrode.

    PubMed

    Koncki, R; Chudzik, A; Walcerz, I

    1999-10-01

    A pH-membrane electrode with n-tridodecylamine (TDDA) as the hydrogen-ion-selective ionophore was used for the construction of a potentiometric biosensor for urea determination. The electrode was enzymatically modified by covalent binding of urease molecules directly to the surface of the potentiometric membrane. Incorporation of the urea biosensor into simple double-channel flow injection analysis (FIA) system allows reproducible urea determination in a millimolar range of concentration. The utility and limitations of the presented biosensor-FIA system for analysis of various real samples has been investigated. The system can be useful for some biomedical and pharmaceutical applications such as analyses of urine, posthaemodialysis fluid and extracts from pharmaceutical ointments containing urea.

  18. 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.

  19. Early diabetic kidney maintains the corticomedullary urea and sodium gradient.

    PubMed

    Qi, Haiyun; Nørlinger, Thomas S; Nielsen, Per M; Bertelsen, Lotte B; Mikkelsen, Emmeli; Xu, Yafang; Stødkilde Jørgensen, Hans; Laustsen, Christoffer

    2016-03-01

    Early diabetic nephropathy is largely undetectable before substantial functional changes have occurred. In the present study, we investigated the distribution of electrolytes and urea in the early diabetic kidney in order to explore whether pathophysiological and metabolic changes appear concomitantly with a decreased sodium and urea gradient. By using hyperpolarized (13)C urea it was possible to measure the essential intrarenal electrolyte gradients and the acute changes following furosemide treatment. No differences in either intrarenal urea or sodium gradients were observed in early diabetes compared to healthy controls. These results indicate that the early metabolic and hypertrophic changes occurring in the diabetic kidney prelude the later functional alterations in diabetic kidney function, thus driving the increased metabolic demand commonly occurring in the diabetic kidney.

  20. Uranium stripping from tributyl phosphate by urea solutions

    NASA Astrophysics Data System (ADS)

    Skripchenko, S. Yu.; Titova, S. M.; Smirnov, A. L.; Rychkov, V. N.

    2016-09-01

    The process of uranium stripping from tri-n-butyl phosphate in kerosene by urea solutions was investigated at the volume ratio of the organic and aqueous phases of (1-10) : 1 in the temperature range of 20-60 °C. The stripping of uranium from a loaded organic phase increased with increasing urea content in the solution and with increasing temperature. Maximum recovery of uranium from tributyl phosphate was obtained using a solution that contained 8-12 mol/l of urea. The application of a urea solution for uranium stripping resulted in the strip product solution containing 200-240 g/L of uranium. The process of uranium stripping by dilute nitric acid was also investigated. Results of uranium stripping by the two methods are compared and discussed.

  1. 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...

  2. Preparation and affinity identification of glutamic acid-urea small molecule analogs in prostate cancer

    PubMed Central

    Zhang, Zhiwei; Zhu, Zheng; Yang, Deyong; Fan, Weiwei; Wang, Jianbo; Li, Xiancheng; Chen, Xiaochi; Wang, Qifeng; Song, Xishuang

    2016-01-01

    In recent years, study concerning activity inhibitors of prostate-specific membrane antigen (PSMA) has been concentrated on the glutamic urea (Glu-urea-R) small molecule and its analogs. The present study aimed to synthesize 4 analogs of Glu-urea-R and identify the affinities of these compounds to PSMA. The compounds were synthesized from raw materials, and the experimental procedures of the present study were in accordance with standard techniques under anhydrous and anaerobic conditions. Glu-urea-Lysine (Glu-urea-Lys), Glu-urea-Ornithine (Glu-urea-Orn), Glu-urea-Glutamine (Glu-urea-Gln) and Glu-urea-Asparagine (Glu-urea-Asn) were successfully synthesized, and their structures were confirmed to be as desired using nuclear magnetic resonance spectroscopy and mass spectrometry. An affinity assay was performed to detect the affinity between the various compounds and PSMA expressed from the prostate cancer LNCap cell line. Glu-urea-Gln had the highest affinity to PSMA, followed by Glu-urea-Asn, Glu-urea-Orn and Glu-urea-Lys. In conclusion, the present study demonstrated that Glu-urea-R specifically binds PSMA expressed in the LNCap cell line and inhibits its activity. PMID:27446384

  3. Exploring the cocrystallization potential of urea and benzamide.

    PubMed

    Cysewski, Piotr; Przybyłek, Maciej; Ziółkowska, Dorota; Mroczyńska, Karina

    2016-05-01

    The cocrystallization landscape of benzamide and urea interacting with aliphatic and aromatic carboxylic acids was studied both experimentally and theoretically. Ten new cocrystals of benzamide were synthesized using an oriented samples approach via a fast dropped evaporation technique. Information about types of known bi-component cocrystals augmented with knowledge of simple binary eutectic mixtures was used for the analysis of virtual screening efficiency among 514 potential pairs involving aromatic carboxylic acids interacting with urea or benzamide. Quantification of intermolecular interaction was achieved by estimating the excess thermodynamic functions of binary liquid mixtures under supercooled conditions within a COSMO-RS framework. The smoothed histograms suggest that slightly more potential pairs of benzamide are characterized in the attractive region compared to urea. Finally, it is emphasized that prediction of cocrystals of urea is fairly direct, while it remains ambiguous for benzamide paired with carboxylic acids. The two known simple eutectics of urea are found within the first two quartiles defined by excess thermodynamic functions, and all known cocrystals are outside of this range belonging to the third or fourth quartile. On the contrary, such a simple separation of positive and negative cases of benzamide miscibility in the solid state is not observed. The difference in properties between urea and benzamide R2,2(8) heterosynthons is also documented by alterations of substituent effects. Intermolecular interactions of urea with para substituted benzoic acid analogues are stronger compared to those of benzamide. Also, the amount of charge transfer from amide to aromatic carboxylic acid and vice versa is more pronounced for urea. However, in both cases, the greater the electron withdrawing character of the substituent, the higher the binding energy, and the stronger the supermolecule polarization via the charge transfer mechanism. PMID:27052722

  4. The Utilization of Urea by the Lichen Cladonia sandstedei.

    PubMed

    Vicente, C; Estrella Legaz, M; Arruda, E C; Xavier Filho, L

    1984-08-01

    The production of both ribitol (which is the translocatable form of reduced carbon) and mannitol (which is the main accumulation form of carbon) by thallus samples of Cladonia sandstedei increases when exogenous urea is supplied to the lichen. In addition, the synthesis of atranorin and its precursor, methyl β-orcinol carboxylate, is also enhanced by urea. A hypothetical action of ammonia released from this nitrogen source on these metabolic processes is suggested. PMID:23194795

  5. Development of a recombinant ureolytic Lactococcus lactis for urea removal.

    PubMed

    Zhang, Suai; Li, Dongxia; Tian, Kai; Bai, Yu; Zhang, Hongkai; Song, Cunjiang; Qiao, Mingqiang; Kong, Deling; Yu, Yaoting

    2009-01-01

    Kidney failure is a common disease with high frequency. Food-grade recombinant bacteria that can effectively remove urea has great potential for treatment of renal failure. A nonpathogenic strain, L. lactis MG1363, was transformed with plasmid pMG36eure, which carries urease gene. The expression of transgene urease in genetically modified L. lactis MG1363 and the urease activity in removal of urea were investigated. It was found that the removal of urea by recombinant L. lactis MG1363 was pH- and nickel-dependent. At pH 6.5 and in the presence of 250 microM of NiSO4, 50 approximately 60% of urea could be removed in 24 hours. The urea removal activity was also evaluated in imitative gastroenteric environment. After being exposed to acidic solution (pH2.5-4.0) for 2 hours, the cells were then grown in a medium containing 0.1 cfu/ml bile acid salt, 30 mg/dl urea, and 250 microM NiSO4 at pH 6.8. The concentration of urea decreased over time, and the removal was about 30% at 10 hours and 65% at 24 hours, respectively. The safety tests were performed by feeding normal rats with either L. lactis MG1363 or recombinant L. lactis MG1363. The two materials did not cause any changes in blood cells and blood biochemical indexes. There were no differences in terms of body weight and water/food consumption between the two materials. These results indicate the safety, feasibility, and capacity of urease gene modified Lactococcus Lactis in removal of urea under the gastroenteric circumstances. Further investigation may generate a food-grade strain for treatment of chronic renal failure.

  6. Glycation of aspartate aminotransferase by methylglyoxal, effect of hydroxycitric and uric acid.

    PubMed

    Bousová, Iva; Bacílková, Eliska; Dobrijević, Sanja; Drsata, Jaroslav

    2009-11-01

    Glycation is a process closely related to the aging and pathogenesis of diabetic complications. Reactive alpha-dicarbonyl compounds (e.g., methylglyoxal) are formed during middle stage of glycation reaction. Compounds that would inhibit the glycation process have been seeked for years. The objective of this study was to investigate the inhibitory effect of hydroxycitric (0.25-2.5 mM) and uric acid (0.4-1.2 mM) on middle stage of protein glycation in vitro using the model containing aspartate aminotransferase (AST) and 0.5 mM methylglyoxal. Hydroxycitric acid, at all tested concentrations, reduced AST activity decrease and formation of fluorescent AGEs during incubation of the enzyme with methylglyoxal at 37 degrees C. This compound also prevented formation of high-molecular weight protein cross-links and changes in molecular charge of AST caused by glycation. Uric acid showed no positive anti-glycation activity. The results support the hypothesis that hydroxycitric acid has beneficial effects in controlling protein glycation. PMID:19449196

  7. 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.

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

    PubMed

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

    2006-10-01

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

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

    PubMed

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

    2014-01-01

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

  10. 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.

  11. Urea-induced oxidative damage in Elodea densa leaves.

    PubMed

    Maleva, Maria; Borisova, Galina; Chukina, Nadezda; Prasad, M N V

    2015-09-01

    Urea being a fertilizer is expected to be less toxic to plants. However, it was found that urea at 100 mg L(-1) caused the oxidative stress in Elodea leaves due to the formation of reactive oxygen species (ROS) and lipid peroxidation that are known to stimulate antioxidant pathway. Urea at a concentration of 500 and 1000 mg L(-1) decreased low-molecular-weight antioxidants. In this case, the antioxidant status of plants was supported by the activity of antioxidant enzymes such as superoxide dismutase and guaiacol peroxidase. A significant increase in the soluble proteins and -SH groups was observed with high concentrations of urea (30-60 % of control). Thus, the increased activity of antioxidant enzymes, low-molecular-weight antioxidants, and induced soluble protein thiols are implicated in plant resistance to oxidative stress imposed by urea. We found that guaiacol peroxidase plays an important role in the removal of the peroxide in Elodea leaves exposed to 1000 mg L(-1)of urea.

  12. 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

  13. 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 10 µL), 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 0-500 mg L(-1) with a detection limit of 0.6 mg L(-1) in urine and 0-250 mg L(-1) with a detection limit of 2.6 mg L(-1) in plasma sample. The limit of quantitation of creatinine was 2.1 mg L(-1) and 8.7 mg L(-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

  14. Quantitation of renal function with 99Tcm-DMSA. A comparison with creatinine clearance in children with single kidney.

    PubMed

    Baillet, G; Gagnadoux, M F; De Vernejoul, P; Broyer, M

    1985-11-01

    To study the accuracy of renal function quantification with 99Tcm-DMSA we compared DMSA renal uptake and creatinine clearance in 16 cases of children with single kidney. The age of the patients ranged from two months to fourteen years. Creatinine clearance was normalized to 1.73 m2. DMSA uptake was measured 7 h after intravenous injection. Background subtraction was used and soft tissue attenuation was taken into account. The uptake was normalized in percentage of the injected activity. A significant correlation was found between creatinine clearance and DMSA uptake (rt = 0.866, p less than 0.01). Normal creatinine clearance range in children (80 to 120 ml min-1/1.73 m2) allowed determination of normal uptake range (36 to 60%). This study indicates that in case of asymmetrical renal impairment renal uptake will reflect split renal creatinine clearance. Since the former is much easier to measure, DMSA should play an important role in the evaluation of differential renal function.

  15. Investigation of the photocatalytic degradation pathway of the urine metabolite, creatinine: the effect of pH.

    PubMed

    Antoniou, Maria G; Nambiar, Usha; Dionysiou, Dionysios D

    2009-09-01

    This study investigated the degradation pathway of creatinine (a urine metabolite) with immobilized titanium dioxide photocatalysts. The degradation of creatinine was studied at three different pH values (acidic, neutral and basic) in the absence of buffering solutions. The intermediates formed were identified by using electrospray ionization mass spectrometer (ESI-MS) in both negative and positive ion mode. Two distinct mechanistic pathways which govern the photocatalytic degradation of creatinine irrespective of the pH of the initial solution were identified. The initial solution pH affected only the selectivity between the two mechanisms. The primary oxidation steps of creatinine with hydroxyl radicals included demethylation, hydrogen abstraction, hydroxylation, oxidation, and ring opening. At acidic pH, additional transformation steps of the two mechanisms were identified. The intermediates detected in the positive ion mode, contained at least one atom of nitrogen in their structure, explaining the observed low nitrogen mineralization of creatinine with TiO(2) photocatalysis. The intermediates in the negative ion mode were low molecular weight organic acids that contained only carbon and hydrogen atoms. PMID:19595423

  16. [Clinical value of the sequential study of the uric acid in CSF in patients with cerebral diseases: Part I. Brain tumor and the effect of irradiation].

    PubMed

    Ueda, T; Wakisaka, S; Kinoshita, K; Adachi, H

    1984-03-01

    Uric acid is the end product of the purine metabolism in the human and is mainly excreted to the urine. The studies on cerebrospinal fluid (CSF) uric acid in patients with various neurological diseases were reported in the literature. In the present study the authors discussed the clinical value of the sequential study of the CSF uric acid content in patients with brain tumors. CSF was investigated for uric acid in 23 controls and 30 cases of brain tumor. The results were as follows: The mean value and standard deviation of the uric acid in CSF in controls was 0.23 +/- 0.13 mg/dl. The uric acid in CSF increased in patients with malignant brain tumor (0.49 +/- 0.22 mg/dl, p less than 0.005), but was in normal range in patients with benign brain tumor (0.32 +/- 0.13 mg/dl, 0.10 less than p less than 0.25). There was no significant correlation between CSF uric acid and CSF protein contents. Uric acid in the lumbar CSF was approximately 4 times higher than in the ventricular CSF in patients with brain tumor. The CSF uric acid had progressively increased during irradiation to the whole brain. The factors contributing to increase of the uric acid in CSF were thought to be increased permeability of blood-CSF barrier, global damage of brain tissue, increased nucleic acid catabolism in the central nervous system (CNS) for example in tumor, inflammation or immunoreaction, increased of xanthine, hypoxanthine or xanthine oxidase activity in the CNS, directly increased of plasma components into the CSF due to such as subarachnoid hemorrhage, intraventricular hemorrhage, bleeding in the tumor or surgical operation, dysfunction of the CSF dynamics.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Radiopaque, iodine functionalized, phenylalanine-based poly(ester urea)s.

    PubMed

    Li, Shan; Yu, Jiayi; Wade, Mary Beth; Policastro, Gina M; Becker, Matthew L

    2015-02-01

    The synthesis and characterization of iodine-functionalized phenylalanine-based poly(ester urea)s (PEUs) are reported. 4-Iodo-L-phenylalanine and L-phenylalanine were separately reacted with 1,6-hexanediol to produce two monomers, bis-4-I-L-phenylalanine-1,6-hexanediol-diester (1-IPHE-6 monomer) and bis-L-phenylalanine-1,6-hexanediol-diester (1-PHE-6 monomer). By varying the feed ratio of the 1-IPHE-6 and 1-PHE-6 monomers, the copolymer composition was modulated resulting in a wide variation in thermal, mechanical and radiopacity properties. Microcomputed tomography (μ-CT) projections demonstrate that increasing iodine content results in greater X-ray contrast. Compression tests of dry and wet porous scaffolds indicate that the poly(1-IPHE-6)0.24-co-poly(1-PHE-6)0.76 material results in the highest compression modulus. MC3T3 cell viability and spreading studies show PEUs are nontoxic to cells. As most medical device procedures require placement verification via fluoroscopic imaging, materials that possess inherent X-ray contrast are valuable for a number of applications.

  18. Clinical value of creatinine kinase in the diagnosis of ectopic pregnancy.

    PubMed

    Vitoratos, N; Gregoriou, O; Papadias, C; Konidaris, S; Kalogirou, D; Kalampokis, D; Chryssikopoulos, A

    1998-08-01

    The role of creatinine kinase (CK) in the diagnosis of ectopic pregnancy was studied. We selected 56 patients divided into 4 groups. Group A consisted of 10 patients with asymptomatic tubal pregnancy, group B consisted of 11 patients with symptomatic tubal pregnancy whereas groups C and D consisted of 20 and 15 patients with normal and threatened intrauterine pregnancy, respectively. Serum samples of CK were taken from all patients on admission. No significant difference was observed in the median CK value of cases with normal pregnancy (58.5 +/- 7.24 U/1, mean +/- SE) as well as threatened abortion (73 +/- 11.43 U/1) compared to that of cases with asymptomatic 58.5 +/- 12.42 U/1) or symptomatic tubal pregnancy (59 +/- 10.08 U/1). We conclude that serum CK is not a useful biochemical marker in the diagnosis of ectopic pregnancy. PMID:9701684

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

    PubMed

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

    2014-11-01

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

  20. Assessment of the amylase--creatinine clearance ratio in postoperative patients.

    PubMed

    Leckie, P A; Ferreira, P; Debas, H T

    1980-08-01

    The value of the amylase--creatinine clearance ratio (ACCR) in the diagnosis of postoperative pancreatitis was prospectively assessed. In 77 patients undergoing operations known to have a significant incidence of postoperative pancreatitis (gastric, biliary or pancreatic) i.e. "high risk" group, the ACCR was abnormally elevated postoperatively in 36 patients (47%). However, overt clinical pancreatitis occurred in only eight patients (10%). In 60 other patients undergoing nonabdominal operations (orthiipedic, head and neck, varicose vein surgery etc.) i.e. "low risk" group, the ACCR was abnormally elevated postoperatively in 23 patients (38%). No patient in this group developed clinical pancreatitis. We conclude, therefore, the ACCR is often abnormally elevated nonspecifically following any type of surgery, and cannot be used as evidence of postoperative pancreatitis. These data do suggest, however, that a normal ACCR, especially on successive daily determinations, might help to exclude the diagnosis of postoperative pancreatitis.