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1

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

Microsoft Academic Search

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

J. T. Lumeij

1987-01-01

2

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

PubMed Central

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

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

2012-01-01

3

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

Microsoft Academic Search

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

J. T. Lumeij; J. D. Remple

1991-01-01

4

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

PubMed

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

Indyk, Harvey E; Woollard, David C

2004-01-01

5

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

PubMed Central

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

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

2013-01-01

6

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

PubMed

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

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

2011-09-01

7

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

PubMed

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. PMID:20188936

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

2010-04-15

8

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

PubMed

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

Mehrdad, Modaresi; Messripour, Manouchehr; Ghobadipour, Mozhgan

2007-09-01

9

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

PubMed

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

Harlow, H J; Nelson, R A

1990-01-01

10

User-defined serum aspartate and alanine aminotransferase, cholesterol, triglycerides, urea, and uric acid for the Beckman synchron CX 4/5 using Ames Sera-Pak reagents.  

PubMed

Beckman aspartate aminotransferase (AST), alanine aminotransferase (ALT), cholesterol, triglycerides, urea, and uric acid Liquid Reagents for Synchron CX 4/5 (48, 48, 25, 60, 26, and 30 cents US/test, respectively) are expensive. We have established our own methods for serum AST, ALT, cholesterol, triglycerides, urea, and uric acid (6, 6, 5, 12, 13, and 6 cents US/test, respectively) using Ames Sera-Pak reagents. Linearity of our AST, ALT, cholesterol, triglycerides, urea, and uric acid methods were either similar to or higher than the Beckman methods. The within run and day-to-day run precisions were acceptable. Recovery of our AST, ALT, cholesterol, triglycerides, urea, and uric acid were excellent. Our results for AST, ALT, cholesterol, triglycerides, urea, and uric acid correlated well with the Beckman results. Bilirubin (340.8 mumol/L) did not significantly interfere on our AST, ALT, cholesterol, triglycerides, and urea, while its concentrations of 165.8 mumol/L started giving negative interference on uric acid. Turbidity (2+) did not interfere significantly on our AST and ALT but started giving positive interference on cholesterol, triglycerides, urea, and uric acid. Hemolysis (2+) gave positive interference on our cholesterol, triglycerides, urea, and uric acid. Stability of Ames Sera-Pak working reagents was at least 30 days for AST, ALT, urea, and uric acid and 40 days for cholesterol and triglycerides. PMID:1403344

Lolekha, P H; Nitipaichit, P

1992-01-01

11

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

PubMed Central

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

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

2012-01-01

12

Estimation of amino acids, urea and uric acid in tasar silkworm, Antheraea mylitta Drury.  

PubMed

The tasar silkworm, Antheraea mylitta Drury, Andhra local ecorace is an exclusive race of Andhra Pradesh. It is on the verge of extinction due to difficulty of acclimatisation at breeding and rearing stages. As an attempt to protect this race, a method of total indoor rearing has been done. In this context, the estimation of free amino acids, excretory products- urea and uric acid were compared during the fourth and fifth instars of tasar silkworm, reared under outdoor and indoor conditions. The study has revealed that amino acids decreased in the fat body in outdoor and indoor reared larvae in contrast to that in the haemolymph where it has gradually increased from first to third crops. This is an important finding as it reveals that indoor worms seem to adopt proteolytic activity in the haemolymph. Secondly, in the fifth instar the excretory products are more compared to fourth instar in the indoor reared worms. During fifth instar, formation of nitrogenous products lessens as silk synthesis enhances. The present study reveals that decrease in uric acid in fifth instar implies increase in growth rate and silk synthesis in both outdoor and indoor worms. The findings of the present investigation is helpful in the conservation and protection of the A. mylitta, Andhra local ecorace. PMID:19297987

Shamitha, G; Rao, A Purushotham

2008-11-01

13

Simultaneous determination of uric acid and creatinine in urine by an eco-friendly solvent-free high performance liquid chromatographic method  

Microsoft Academic Search

A simple, rapid, and eco-friendly analytical method for simultaneous determination of uric acid and creatinine in urine applying high performance liquid chromatography (HPLC) is described. After dilution, de-protein, and filtration, the sample solution was injected to separate the species with C-18 column by an eluent containing 0.05 M ammonium phosphate buffer at pH 7.4. An UV detector was used to

Jen-Fon Jen; Shih-Liang Hsiao; Kang-Hsiung Liu

2002-01-01

14

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

PubMed Central

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

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

2014-01-01

15

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

PubMed Central

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

Sokal, Pawel; Jastrzebski, Zbigniew; Jaskulska, Ewelina; Sokal, Karol; Jastrzebska, Maria; Radziminski, Lukasz; Dargiewicz, Robert; Zielinski, Piotr

2013-01-01

16

Guanidinosuccinic Acid on Human Platelet Effects of Exogenous Urea, Creatinine, and Aggregation In Vitro  

Microsoft Academic Search

a bleeding tendency associated with a prolonged bleeding time and an ade- quate platelet count. We have tested the effectson plateletaggregation of three compounds that are found in in- creased concentration in the blood of patients with renal failure. The addi- tion of urea was followed by an imme- diate, but transient, increase in optical density of platelet-rich plasma. This

James W. Davis; James R. McField; Phyllis E. Phillips; Barbara A. Graham

17

Spectrophotometric simultaneous determination of orotic acid, creatinine and uric acid by orthogonal signal correction-partial least squares in spiked real samples.  

PubMed

An orthogonal signal correction-partial least squares (OSC-PLS) method was developed for the simultaneous spectrophotometric determination of orotic acid (OA), creatinine (CRE), and uric acid (UA) in spiked real samples. By multivariate calibration methods, such as PLS regression, it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. The effect of OSC used to remove the information unrelated to the target variables is studied. In this study, the calibration model is based on absorption spectra in the 220-320 nm rang for 36 different mixtures of OA, CRE and UA. Calibration matrices contained 1.74-47.00 of OA, 1.13-33.95 of CRE, and 1.68-28.58 of UA in µg/ml. The number of principal component for OA, CRE, and UA with OSC were 3, 4, and 4, and 4, 6, and 5, without OSC, respectively. The evaluation of the prediction errors for the prediction set reveals that the OSC-treated data give substantially lower root mean square error of prediction (RMSEP) values than the original data. The RMSEP for OA, CRE, and UA with OSC were 0.69, 0.20, and 0.53 and 0.80, 0.69, and 0.73 without OSC, respectively. The proposed method was applied for the simultaneous determination of OA, CRE, and UA in spiked biological fluids with satisfactory results. PMID:22371390

Khajehsharifi, Habiboallah; Tavallali, Hossein; Shekoohi, Manzar; Sadeghi, Maasumeh

2013-05-01

18

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

Microsoft Academic Search

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

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

2005-01-01

19

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

20

Effect of uric acid on gentamicin-induced nephrotoxicity in rats - role of matrix metalloproteinases 2 and 9.  

PubMed

In this work, we aimed to study the effect of uric acid on gentamicin-induced nephrotoxicity. Male Sprague-Dawley rats were assigned to one of six groups (six rats each) which received intraperitoneal injections for 9 days: (S) saline; (UA) Uric acid alone; (G) Gentamicin alone; (G + UA) Gentamicin + uric acid; (G rec) Gentamicin recovery and (G + UA rec) Gentamicin + uric acid recovery. In (G rec) and (G + UA rec), rats recovered for 7 days after the last injection. Urine and blood samples were taken on day 0 and at the end of every stage. Kidneys were harvested for histological scoring, determination of renal malondialdehyde (MDA), zymography and western blots for matrix metalloprotease (MMP)-2 and MMP-9. Uric acid alone did not provoke changes in biochemical and histological parameters when compared to controls. Gentamicin alone increased significantly plasma creatinine and blood urea nitrogen and caused a moderate histological damage. When combined with uric acid, these conditions worsened. MMP-9 activity and expression was decreased in rats from group G + UA as compared with rats from group G, while activity of MMP-2 was similarly increased in both groups when compared to controls. The increase in renal MDA induced by gentamicin was not altered when it was combined with uric acid. During the recovery stage, all biochemical parameters returned to normal levels, though a trend for delay of tubular damage recovery was observed in group G + UA rec when compared with group G rec. The results indicate that uric acid worsens gentamicin-induced nephrotoxicity. The mechanism is likely to implicate down-regulation of MMP-9. PMID:19821833

Romero, Freddy; Pérez, Mariela; Chávez, Maribel; Parra, Gustavo; Durante, Paula

2009-12-01

21

Prediction of Creatinine Clearance from Serum Creatinine  

Microsoft Academic Search

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

Donald W. Cockcroft; Henry Gault

1976-01-01

22

Uric Acid Test  

MedlinePLUS

... purine metabolism . Metastatic cancer, multiple myeloma , leukemias , and cancer chemotherapy can cause increased production of uric acid. Chronic renal disease , acidosis , toxemia of pregnancy , and alcoholism can cause ...

23

Urine alkalization facilitates uric acid excretion  

PubMed Central

Background Increase in the incidence of hyperuricemia associated with gout as well as hypertension, renal diseases and cardiovascular diseases has been a public health concern. We examined the possibility of facilitated excretion of uric acid by change in urine pH by managing food materials. Methods Within the framework of the Japanese government's health promotion program, we made recipes which consist of protein-rich and less vegetable-fruit food materials for H+-load (acid diet) and others composed of less protein but vegetable-fruit rich food materials (alkali diet). Healthy female students were enrolled in this consecutive 5-day study for each test. From whole-day collected urine, total volume, pH, organic acid, creatinine, uric acid and all cations (Na+,K+,Ca2+,Mg2+,NH4+) and anions (Cl-,SO42-,PO4-) necessary for the estimation of acid-base balance were measured. Results Urine pH reached a steady state 3 days after switching from ordinary daily diets to specified regimens. The amount of acid generated ([SO42-] +organic acid-gut alkai) were linearly related with those of the excretion of acid (titratable acidity+ [NH4+] - [HCO3-]), indicating that H+ in urine is generated by the metabolic degradation of food materials. Uric acid and excreted urine pH retained a linear relationship, where uric acid excretion increased from 302 mg/day at pH 5.9 to 413 mg/day at pH 6.5, despite the fact that the alkali diet contained a smaller purine load than the acid diet. Conclusion We conclude that alkalization of urine by eating nutritionally well-designed food is effective for removing uric acid from the body. PMID:20955624

2010-01-01

24

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

PubMed

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

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

2012-01-01

25

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

PubMed Central

Background: Various findings suggest that uric acid is an inflammatory factor and may have a role in endothelial dysfunction and act as a mediator of diabetic nephropathy. The objective of this study was to evaluate the relationships between serum uric acid level and level of proteinuria in type 2 diabetic (T2D) patients. Materials and Methods: A cross-sectional analytical study was conducted in 60 patients with T2D without a history of gout. None was treated with allopurinol. Venous blood samples were obtained in fasting state for determinations of serum creatinine, uric acid, and hemoglobin A1c (HbA1c) (reference range 3.8-5.5%); 24-h urine proteinuria was also measured. Results: Mean age of the patients was 57 ± 8.3 years. Mean ± standard error (SE) of serum creatinine was 0.98 ± 0.028 mg/dL, mean ± SE of serum uric acid was 4.5 ± 0.15 mg/dL, and mean ± SE of proteinuria was 388 ± 28.7 mg/day (median = 303.5 mg/day). There was no significant difference in serum uric acid, HbA1c, and creatinine level between males and females (P > 0.05). There was a significant positive association between body mass index (BMI) and serum uric acid levels (r = 0.428, P = 0.001). After adjustment for weight, a significant positive association of serum uric acid with level of proteinuria was seen (r = 0.47, P < 0.001). Conclusion: Serum uric acid had a significant positive association with diabetic nephropathy. It might be hypothesized that serum uric acid plays a role in diabetic nephropathy in T2D. PMID:23900353

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

2013-01-01

26

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

PubMed Central

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

2012-01-01

27

Relationship between serum uric acid levels and hepatic steatosis in non-obese postmenopausal women.  

PubMed

Abstract Objective Serum uric acid levels have been reported to be associated with non-alcoholic fatty liver disease (NAFLD). However, very few studies specifically examining the relationship between serum uric acid (SUA) levels and NAFLD in postmenopausal women have been reported in China, especially in postmenopausal women with normal body mass index (BMI) in whom NAFLD is not uncommon. Methods A cross-sectional study was employed of 528 Chinese normal-BMI postmenopausal women (aged 41-79 years) who participated in annual health check-ups. NAFLD is defined as a hepatic steatosis observed on liver ultrasonography in the absence of a second cause. Of all the participants, 121 women were diagnosed with hepatic steatosis (NAFLD group) and the others were without (non-NAFLD group). SUA quartiles were defined as follows: Q1, < 3.8 mg/dl; Q2, 3.8-4.4 mg/dl; Q3, 4.5-5.0 mg/dl; Q4, 5.1-6.0 mg/dl. Stepwise multivariable regression analysis was used to assess the relationships between SUA level and other variables. The association between SUA quartiles and hepatic steatosis was assessed using binary logistic regression. Results Compared to the non-NAFLD group, the mean level of SUA was significantly higher in the NAFLD group (p < 0.01). The adjusted odds ratio (95% confidence interval) for the presence of hepatic steatosis in the highest SUA quartile vs. the lowest quartile was 2.774 (1.396-5.513) for all women (p < 0.01) after adjusting for the factors which were independently associated with uric acid level including waist circumference, high blood pressure, blood urea nitrogen, creatinine, ?-glutamyltransferase, and triglycerides. Most estimates changed little after further adjustment for age, metabolic syndrome, drinking status, and smoking status. The presence of hepatic steatosis significantly increased in the third and fourth quartiles of SUA. The prevalence of hepatic steatosis increased gradually with an increasing SUA quartile (p for trend < 0.01). Conclusion Higher SUA levels even within the normal range are positively and independently associated with the presence of hepatic steatosis in Chinese postmenopausal women with normal BMI. PMID:24884478

Liu, P J; Ma, F; Lou, H P; Zhu, Y N; Chen, Y

2014-12-01

28

Effects of the N/L-Type Calcium Channel Blocker Cilnidipine on Nephropathy and Uric Acid Metabolism in Hypertensive Patients With Chronic Kidney Disease (J-CIRCLE Study).  

PubMed

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

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

2014-10-01

29

[Vesical uric acid lithiasis in a child with renal hypouricemia].  

PubMed

We report a 12-month-old boy with renal hypouricemia who presented with crying due to obstructing vesicourethral uric acid stones. Metabolic study revealed persistent acidic urine with normal blood pH, and hypouricemia (1.4-1.7 mg/dl) with an increased ratio of uric acid clearance to creatinine clearance (24-32 %). Pyrazinamide produced no response but the patient showed a positive response to benzbromarone. These findings were consistent with a presecretory defect. No other tubular dysfunctions, such as renal glycosuria, aminoaciduria or phosphaturia were found. The patient underwent surgical treatment and was subsequently treated with potassium citrate. After a 2-year follow-up, he remains asymptomatic, despite persistent hyperuricosuria. To our knowledge, this is the youngest reported case of renal hypouricemia and lithiasis. PMID:11676906

Martín Hernández, E; Aparicio López, C; Alvarez Calatayud, G; García Herrera, M A

2001-09-01

30

The relationship between uric acid and potassium in normal subjects.  

PubMed Central

The serum uric acid concentration in normal healthy subjects has been studied in relation to sex, height, weight, lean body mass measured from total body potassium and predicted from the Hume-Weyers formula (1971), total body potassium, plasma potassium and urea, and packed cell volume. The strongest correlation was found with sex, but height, weight, total body potassium, lean body mass (measured and predicted) also correlated significantly with serum uric acid concentration. However, when the sex variable was removed, the other factors lost their significant correlation. Finally, total red blood cell and plasma volumes were predicted (Hume and Goldberg, 1964) and from these an estimate of total plasma uric acid, total plasma potassium, and total red blood cell potassium obtained. Measured total body potassium was found to correlate well with total plasma potassium and total red blood cell potassium independent of sex. Total plasma uric acid correlated well with measured total body potassium when both sexes were considered and when separated into male and female groups the males retained a significant correlation as did the female group. PMID:686865

Kennedy, A C; Boddy, K; King, P C; Brennan, J; Anderson, J A; Buchanan, W W

1978-01-01

31

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

SciTech Connect

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

Meadows, J.R.

1986-01-01

32

Residual renal function and post dialysis urea rebound.  

PubMed

Kt/v is used to estimate haemodialysis prescription and treatment adequacy and usually does not include evaluation of urea rebound. In addition urea clearance provided by the presence of residual renal function (RRF) is additive to dialytic urea clearance. Rebound is a phenomenon involving other molecules such as creatinine and phosphorus. The aim of this study was to investigate the role of RRF on post dialysis urea, creatinine and phosphorus rebounds. We investigated 7 patients with RRF (group 1) and 7 uraemic anuric patients (group 2). Urea rebound was lower in group 1 than group 2: 9.5 +/- 4% vs 18 +/- 7% (p = 0.04). Creatinine rebound and phosphorus rebound were similar in both groups 15.2 +/- 9% group 1 vs 14.6 +/- 5% group 2 (p = NS) and 16.7 +/- 7% group 1 vs 20 +/- 7% group 2 (p = NS) respectively. Our data suggest Kt/v calculated without considering rebound overestimates haemodialysis efficacy. PMID:10531872

Carofei, O; Taratufolo, A; Atti, S; Fringuello, F; Alaimo, M

1999-01-01

33

Determinants of plasma uric acid  

Microsoft Academic Search

Obesity, alcohol consumption, and hematocrit provide an index of plasma uric acid, which in path analysis has a cultural heritability of 0.11 in children and 0.23 in parents, a small maternal effect, and a genetic heritability of 0.25 in both generations. Preliminary evidence for a major locus is destroyed by the omission of one exceptional child. There is no evidence

C. L. Gulbrandsen; N. E. Morton; D. C. Rao; G. G. Rhoads; A. Kagan

1979-01-01

34

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

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

35

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

PubMed Central

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

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

2014-01-01

36

Decrease in Urinary Creatinine Excretion in Early Stage Chronic Kidney Disease  

PubMed Central

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

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

2014-01-01

37

Uric Acid, Hyperuricemia and Vascular Diseases  

PubMed Central

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

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

2011-01-01

38

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

PubMed

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

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

2014-07-01

39

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

PubMed Central

Context. Sampling blood for serum analysis is an invasive procedure. A noninvasive alternative would be beneficial to patients and health care professionals. Aim. To correlate serum and salivary creatinine levels and evaluate the role of saliva as a noninvasive alternative to serum for creatinine estimation in chronic kidney disease patients. Study Design. Case-control study. Methods. Blood and saliva samples were collected from 37 healthy individuals and 105 chronic kidney disease patients. Serum and salivary creatinine levels were estimated using automatic analyser. Statistical Analysis. The serum and salivary creatinine levels between controls and cases were compared using t-test. Correlation between serum and salivary creatinine was obtained in controls and cases using Pearson correlation coefficient. Receiver operating characteristic analysis was done to assess the diagnostic performance of salivary creatinine. Cut-off values were established for salivary creatinine. Results. Serum and salivary creatinine levels were significantly higher in CKD patients than controls. The correlation was negative in controls and positive in cases. Area under the curve for salivary creatinine was found to be 0.967. A cut-off value of 0.2?mg/dL gave a sensitivity of 97.1% and specificity of 86.5%. Conclusion. Saliva can be used as a noninvasive alternative to serum for creatinine estimation. PMID:24818023

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

2014-01-01

40

Plasma Creatinine Clearance in the Dog  

ERIC Educational Resources Information Center

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

Frazier, Loy W.

1977-01-01

41

Original article Evaluation of urinary creatinine excretion  

E-print Network

estimation of body com- position in ruminants. Borsook and Dubnoff [2] found that 98% of the creatine, but DelGiudice [7] stated that dietary sources of creatine or creatinine (e.g. meat) may be important

Boyer, Edmond

42

Correlation Between Serum Uric Acid and Renal Function in Patients With Stable Coronary Artery Disease and Type 2 Diabetes  

PubMed Central

Background The aim of this study was to investigate the relationship between serum uric acid and renal function, expressed as estimated glomerular filtration rate (eGFR), in patients with stable coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM) in China. Methods Serum levels of uric acid and creatinine were determined in 526 enrolled patients diagnosed with stable CAD and T2DM. To assess renal function, eGFR was calculated using a modified MDRD formula suitable for the Chinese population. Patients’ anthropometric measurements were collected using standardized protocols, and 6-month follow-up results were collected and analyzed. Pearson’s correlation coefficient r was calculated and multivariate analysis was performed to evaluate the relationship between uric acid and renal function. Patients with eGFR < 60 mL/min/1.73 m2 were classified as having reduced renal function or chronic kidney disease (CKD) in this study. Results Uric acid levels were negatively associated with eGFR (P = 0.002), especially in patients with CKD (eGFR < 60 mL/min/1.73 m2) (P < 0.001). In patients with reduced renal function, the risk in the highest quartile of uric acid levels was higher than in the lowest quartile (odds ratio 9.18, 95% confidence interval: 4.01 - 21.01, P < 0.001). These associations remained after multiple adjustments for potential confounders and were recapitulated after 6-month follow-up. Conclusions Serum uric acid level is negatively associated with renal function, as assessed by eGFR, and serves as an independent predictor for CKD in patients with stable CAD and T2DM.

Chen, Zhong; Ding, Zhen; Fu, Cong; Yu, Chaojun; Ma, Genshan

2014-01-01

43

SOURCE ASSESSMENT: UREA MANUFACTURE  

EPA Science Inventory

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

44

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

PubMed

We measured changes in the protein: creatinine and trypsin inhibitor: creatinine ratios in the urine of six male marathon runners. Samples of urine were collected before the run, immediately after the run and in 6-h collections for 2 days. We found the greatest increase in the protein: creatinine ratio (2.6 times greater) in urine collected immediately after the run and the greatest increase in the trypsin inhibitor: creatinine ratio in urine samples collected 6-12 and 12-18 h after the run (2 and 3 times greater, respectively). This suggests the existence of different mechanisms for these two physiological processes. The later increase in the trypsin inhibitor: creatinine ratio was perhaps, due to a state of short-lived inflamation and shock after severe physical effort. PMID:2289488

Borkowski, J; Sobiech, K A

1990-01-01

45

Uric acid as a risk factor for progression of non-diabetic chronic kidney disease? The Mild to Moderate Kidney Disease (MMKD) Study.  

PubMed

The kidney is one of the organs most prominently affected by aging. This can be seen by a loss of renal mass which is caused by a decrease in the number of nephrons resulting in hyperfiltration, hypertrophy and elevations in glomerular pressure. The factors influencing aging of the kidney are not fully elucidated. Epidemiological, experimental and interventional studies resulted in inconsistent results and have not firmly established whether uric acid levels affect progression of Chronic Kidney Disease (CKD). Therefore, we analyzed whether uric acid levels predict the progression of CKD in the Mild to Moderate Kidney Disease Study comprising at baseline 227 Caucasian patients aged 18-65 years with primary non-diabetic CKD of various degrees of renal impairment. Of them, 177 completed a prospective follow-up of 7 years. Primary endpoint was progression of CKD defined as doubling of baseline serum creatinine and/or terminal renal failure. Patients who reached a progression endpoint (n =6 5) were significantly older, had higher baseline serum creatinine and protein excretion rates as well as lower Glomerular Filtration Rate (GFR). Uric acid levels were only higher in patients with progression of disease when patients with uric acid-lowering drugs were excluded from the analysis. Cox regression analysis revealed that increasing uric acid levels predict disease progression only when the analysis was not adjusted for baseline kidney function parameters. As soon as we adjusted the analysis for GFR and proteinuria this association completely vanished. In summary, our prospective 7 year follow-up study in patients with non-diabetic primary CKD did not support uric acid as an independent predictor for CKD progression. PMID:18294794

Sturm, Gisela; Kollerits, Barbara; Neyer, Ulrich; Ritz, Eberhard; Kronenberg, Florian

2008-04-01

46

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

PubMed

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

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

2014-10-01

47

Luteolin prevents uric acid-induced pancreatic ?-cell dysfunction  

PubMed Central

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

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

2014-01-01

48

Creatinine Inhibits D-Amino Acid Oxidase  

Microsoft Academic Search

Inhibition of D-amino acid oxidase (DAO) activity by various uremic retention products and guanidino compounds was investigated. Creatinine (CTN) was found to inhibit DAO at a similar concentration in the sera of uremic patients. The inhibition was competitive and the Ki value was 2.7 mM. Moreover, CTN was shown to interact with flavin adenine dinucleotide (FAD), a coenzyme of DAO.

Y. Nohara; J. Suzuki; T. Kinoshita; M. Watanabe

2002-01-01

49

The regulation of urea-biosynthesis enzymes in vertebrates  

PubMed Central

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

Mora, J.; Martuscelli, J.; Ortiz-Pineda, Juana; Soberón, G.

1965-01-01

50

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

NASA Astrophysics Data System (ADS)

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

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

51

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

PubMed Central

Introduction Acute kidney injury (AKI) diagnosis is based on an increase in plasma creatinine, which is a slowly changing surrogate of decreased glomerular filtration rate. We investigated whether serial creatinine clearance, a direct measure of the glomerular filtration rate, provided more timely and accurate information on renal function than serial plasma creatinine in critically ill patients. Methods Serial plasma creatinine and 4-hour creatinine clearance were measured 12-hourly for 24 hours and then daily in 484 patients. AKI was defined either as > 50% increase in plasma creatinine from baseline, or > 33.3% decrease in creatinine clearance. The diagnostic and predictive performance of the two AKI definitions were compared. Results Creatinine clearance decrease diagnosed AKI in 24% of those not diagnosed by plasma creatinine increase on entry. These patients entered the ICU sooner after insult than those diagnosed with AKI by plasma creatinine elevation (P = 0.0041). Mortality and dialysis requirement increased with the change in creatinine clearance-acute kidney injury severity class (P = 0.0021). Amongst patients with plasma creatinine < 1.24 mg/dl on entry, creatinine clearance improved the prediction of AKI considerably (Net Reclassification Improvement 83%, Integrated Discrimination Improvement 0.29). On-entry, creatinine clearance associated with AKI severity and duration (P < 0.0001) predicted dialysis need (area under the curve: 0.75) and death (0.61). A > 33.3% decrease in creatinine clearance over the first 12 hours was associated with a 2.0-fold increased relative risk of dialysis or death. Conclusions Repeated 4-hour creatinine clearance measurements in critically ill patients allow earlier detection of AKI, as well as progression and recovery compared to plasma creatinine. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN012606000032550. PMID:22713519

2012-01-01

52

Uric acid inhibits placental system A amino acid uptake.  

PubMed

Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasing uric acid concentrations in preeclamptic women is in part the result of uric acid-induced reductions in amino acid transport across the placenta. The objective of the current study was to examine the effects of uric acid on human placental System A amino acid transport using a primary placental villous explant model. Further, we examined the necessity of uric acid uptake and the role of redox signaling as a potential mechanism through which uric acid may attenuate System A activity. Placental uptake of a radiolabeled amino acid analogue, specific to the System A transporter, was reduced in a concentration-dependent fashion with increasing uric acid (0-7 mg/dL), corresponding to uric acid concentrations measured in healthy pregnant and preeclamptic women in the third trimester. Uric acid-induced reduction in System A activity was partially reversed by NADPH oxidase inhibition and completely eliminated by antioxidant treatment. This study demonstrates inhibition of placental System A amino acid transport with uric acid treatment, as a result of uric acid-induced stimulation of intracellular redox signaling cascades. These findings may be relevant to the increased frequency of fetal growth restriction observed in hyperuricemic preeclampsia. Additionally the results of this study, indicating a detrimental effect of hyperuricemia on amino acid transport in the placenta, at concentrations present in women with preeclampsia, also suggest a role for uric acid in the pathophysiology of preeclampsia. PMID:19058847

Bainbridge, S A; von Versen-Höynck, F; Roberts, J M

2009-02-01

53

Uric Acid Inhibits Placental System A Amino Acid Uptake?  

PubMed Central

Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasing uric acid concentrations in preeclamptic women is in part the result of uric acid-induced reductions in amino acid transport across the placenta. The objective of the current study was to examine the effects of uric acid on human placental System A amino acid transport using a primary placental villous explant model. Further, we examined the necessity of uric acid uptake and the role of redox signaling as a potential mechanism through which uric acid may attenuate System A activity. Placental uptake of a radiolabeled amino acid analogue, specific to the System A transporter, was reduced in a concentration-dependent fashion with increasing uric acid (0?7 mg/dL), corresponding to uric acid concentrations measured in healthy pregnant and preeclamptic women in the third trimester. Uric acid-induced reduction in System A activity was partially reversed by NADPH oxidase inhibition and completely eliminated by antioxidant treatment. This study demonstrates inhibition of placental System A amino acid transport with uric acid treatment, as a result of uric acid-induced stimulation of intracellular redox signaling cascades. These findings may be relevant to the increased frequency of fetal growth restriction observed in hyperuricemic preeclampsia. Additionally the results of this study, indicating a detrimental effect of hyperuricemia on amino acid transport in the placenta, at concentrations present in women with preeclampsia, also suggest a role for uric acid in the pathophysiology of preeclampsia. PMID:19058847

Bainbridge, S.A.; von Versen-Hoynck, F.; Roberts, J.M.

2009-01-01

54

Limitations of creatinine as a filtration marker in glomerulopathic patients  

Microsoft Academic Search

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

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

1985-01-01

55

Role of insulin resistance in uric acid nephrolithiasis.  

PubMed

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

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

2014-11-01

56

Role of insulin resistance in uric acid nephrolithiasis  

PubMed Central

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

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

2014-01-01

57

Surface-enhanced Raman spectroscopy of creatinine in silver colloid  

NASA Astrophysics Data System (ADS)

Surface enhanced Raman spectroscopy (SERS) technology has already made great progress in bio-molecule detection. It can make the target molecules strongly absorbed onto the surface of metal nanoparticles, and then the Raman signal of its own has been greatly enhanced through physical and chemical enhancement mechanisms. We report the SERS spectra of creatinine in silver colloid, and study the silver colloid enhanced effects on the Raman scattering of creatinine. We can also find that creatinine concentration is linearly related to its SERS peak intensity and the detection limit of creatinine silver sol is found to be 10 mg/dl. In conclusion, we can observe that the silver colloid has very good enhanced effects for the creatinine. The potential applications of SERS in quantitative measurement of the creatinine liquor are demonstrated. The result shows that the SERS approach would provide a unique and fast test method for creatinine detection.

Wang, Yue; Chen, Jiesi; Wu, Yanan; Chen, Yanping; Pan, Jianji; Lei, Jinping; Chen, Yongjian; Sun, Liqing; Feng, Shangyuan; Chen, Rong

2011-11-01

58

Surface-enhanced Raman spectroscopy of creatinine in silver colloid  

NASA Astrophysics Data System (ADS)

Surface enhanced Raman spectroscopy (SERS) technology has already made great progress in bio-molecule detection. It can make the target molecules strongly absorbed onto the surface of metal nanoparticles, and then the Raman signal of its own has been greatly enhanced through physical and chemical enhancement mechanisms. We report the SERS spectra of creatinine in silver colloid, and study the silver colloid enhanced effects on the Raman scattering of creatinine. We can also find that creatinine concentration is linearly related to its SERS peak intensity and the detection limit of creatinine silver sol is found to be 10 mg/dl. In conclusion, we can observe that the silver colloid has very good enhanced effects for the creatinine. The potential applications of SERS in quantitative measurement of the creatinine liquor are demonstrated. The result shows that the SERS approach would provide a unique and fast test method for creatinine detection.

Wang, Yue; Chen, Jiesi; Wu, Yanan; Chen, Yanping; Pan, Jianji; Lei, Jinping; Chen, Yongjian; Sun, Liqing; Feng, Shangyuan; Chen, Rong

2012-03-01

59

Biohydrolysis of urea from urea-bearing wastewater.  

PubMed

Biological stabilization of urea is a two staged process; (i) urea hydrolysis and (ii) ammonia stripping/nitrification-denitrification. Ammonia thus produced is either stripped off by usual methods or after converting into nitrate using chemoautotrophic bacteria. On denitrification, nitrate is finally converted into nitrogen gas by means of heterotrophic bacteria. Details of stabilization of urea from urea bearing wastewater using urea biohydrolyser are presented in this paper. PMID:14672371

Pathe, Pradhyumna P; Tapas, Nandy; Kaul, Santosh N; Deshpande, Chandrasekhar V; Szpyrkowicz, Lidia

2003-01-01

60

Uric Acid as a Pathogenic Factor in Preeclampsia  

PubMed Central

Hyperuricemia is a common finding in preeclamptic pregnancies evident from early pregnancy. Despite the fact that elevated uric acid often pre-dates the onset of clinical manifestations of preeclampsia, hyperuricemia is usually considered secondary to altered kidney function. Increased serum uric acid is associated with hypertension, renal disease and adverse cardiovascular events in the non-pregnant population and with adverse fetal outcomes in hypertensive pregnancies. We hypothesize that an elevated concentration of uric acid in preeclamptic women is not simply a marker of disease severity but rather contributes directly to the pathogenesis of the disorder. Using epidemiological and experimental evidence, gained largely outside of pregnancy, we will propose pathogenic roles for uric acid in preeclamptic pregnancies. Uric acid's ability to promote inflammation, oxidative stress and endothelial dysfunction will be highlighted with discussions of the potential impact on placental development and function and maternal vascular health. PMID:18093648

Bainbridge, Shannon A.; Roberts, James M.

2009-01-01

61

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

PubMed

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

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

2011-06-01

62

Can two, four or eight?hour urine collections after voluntary voiding be used instead of twenty ?four hour collections for the estimation of creatinine clearance in healthy subjects  

Microsoft Academic Search

The accuracy of creatinine clearance estimations obtained from 4-hour (16:00-20:00, 20:00-24:00, 08:00-12:00, 12:00-16:00) and 8-hour (16:00-24:00, 24:00-08:00 and 08:00-16:00) urine collections and the Cockcroft Gault formula compared with the standard 24-hour collection, as well as the cyclical variation in creatinine excretion were studied in a group of 22 healthy subjects (Serum creatinine < 1.5mg\\/dl, Blood Urea Nitrogen < 50mg\\/dl) after

Sophia L. Markantonis

1998-01-01

63

Measurement of Serum Creatinine - Current Status and Future Goals  

PubMed Central

The first methods for the measurement of creatinine in serum and plasma were published over a century ago. Today, the Jaffe reaction using alkaline picrate remains the cornerstone of most current routine methods, after continuous refinements attempting to overcome inherent analytical interferences and limitations. With the recent introduction of the reporting of estimated glomerular filtration rate (eGFR), inter-laboratory agreement of serum creatinine results has become an important international priority. Expert professional bodies have recommended that all creatinine methods should become traceable to a reference method based on isotope dilution-mass spectrometry (IDMS). It is important that clinical biochemists have a good understanding of the relative performance of routine creatinine methods. Using a new commutable IDMS-traceable reference material (SRM 967), and a validated tandem IDMS assay developed in our laboratory, we assessed the accuracy of nine routine creatinine methods with assistance from other laboratories in our region. Three methods appeared to have patient sample bias that exceeded 5% in the range of creatinine concentrations where eGFR estimations are most important. Companies are currently recalibrating their creatinine assays. This task should be complete in 2007, and then creatinine results for eGFR calculations will require the use of a modified eGFR equation. Laboratories considering calibration changes before this time can seek advice from the Australasian Creatinine Working Group. PMID:17581641

Peake, *Michael; Whiting, Malcolm

2006-01-01

64

21 CFR 862.1225 - Creatinine test system.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

65

21 CFR 862.1225 - Creatinine test system.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

66

21 CFR 862.1225 - Creatinine test system.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

67

21 CFR 862.1225 - Creatinine test system.  

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

2014-04-01

68

Increased creatinine clearance in polytrauma patients with normal serum creatinine: a retrospective observational study  

PubMed Central

Introduction The aim of this study, performed in an intensive care unit (ICU) population with a normal serum creatinine, was to estimate urinary creatinine clearance (CLCR) in a population of polytrauma patients (PT) through a comparison with a population of non trauma patients (NPT). Methods This was a retrospective, observational study in a medical and surgical ICU in a university hospital. A total of 284 patients were consecutively included. Two different groups were studied: PT (n = 144) and NPT (n = 140). Within the second week after admission to the ICU, renal function was assessed using serum creatinine, 24 h urinary CLCR . Results Among the 106 patients with a CLCR above 120 mL minute-1 1.73 m-2, 79 were PT and 27 NPT (P < 0.0001). Only 63 patients had a CLCR below 60 mL minute-1 1.73 m-2 with 15 PT and 48 NPT (P < 0.0001). Patients with CLCR greater than 120 mL minute-1. 1.73 m -2 were younger, had a lower SAPS II score and a higher male ratio as compared to those having CLCR lower than 120 mL minute-1. 1.73 m -2. Through a logistic regression analysis, age and trauma were the only factors independently correlated to CLCR. Conclusions In ICU patients with normal serum creatinine, CLCR, is higher in PT than in NPT. The measure of CLCR should be proposed as routine for PT patients in order to adjust dose regimen, especially for drugs with renal elimination. PMID:21291554

2011-01-01

69

First trimester uric acid and adverse pregnancy outcomes  

PubMed Central

BACKGROUND The association of elevated serum uric acid with the development of hypertension is established outside of pregnancy. We investigated whether first trimester uric acid was associated with the development of the following: gestational hypertension or preeclampsia, these outcomes stratified by presence of hyperuricemia at delivery since this denotes more severe disease, preterm birth or small for gestational age (SGA). METHODS Uric acid was measured in 1541 banked maternal plasma samples from a prior prospective cohort study that were collected at a mean gestational age of 9.0 (± 2.5) weeks. Polytomous regressions were performed and adjusted for parity and pre-pregnancy body mass index. RESULTS First trimester uric acid in the highest quartile (>3.56 mg/dL) compared to lowest three quartiles was associated with an increased risk of developing preeclampsia (adjusted OR = 1.82; 95% CI, 1.03–3.21) but not gestational hypertension. In women with hypertensive disease complicated by hyperuricemia at delivery, high first trimester uric acid was associated with a 3.22-fold increased risk of hyperuricemic gestational hypertension and a 3.65-fold increased risk of hyperuricemic preeclampsia. High first trimester uric acid was not associated with gestational hypertension or preeclampsia without hyperuricemia at delivery, preterm birth, or SGA. In women who developed hypertensive disease, elevated uric acid at delivery was only partly explained by elevated uric acid in the first trimester (r2 = .23). CONCLUSIONS First trimester elevated uric acid was associated with later preeclampsia and more strongly with preeclampsia and gestational hypertension with hyperuricemia. PMID:21252861

Laughon, S.K.; Catov, J.; Powers, R.W.; Roberts, J.M.; Gandley, R.E.

2011-01-01

70

Chemiresistor urea sensor  

DOEpatents

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

Glass, Robert S. (Livermore, CA)

1997-01-01

71

Calibrationless Determination of Creatinine and Ammonia by Coulometric Flow Titration  

Microsoft Academic Search

A precise and sensitive working microflow titration procedure was developed to determine creatinine and ammonia in urine samples. This procedure is based on enzymatic conversion of creatinine, gas diffusional membrane separation of the released ammonia into an acid acceptor stream, and coulometric titration of ammonia with hypobromite. The hypobromite is formed after the electrogeneration of bromine in an electrolyte containing

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

2000-01-01

72

Uric Acid as a Mediator of Diabetic Nephropathy  

PubMed Central

Despite the advances in the management of patients with diabetes, diabetic nephropathy (DN) remains the most common cause of end stage renal disease (ESRD) in the US and worldwide. Inflammation and endothelial dysfunction appear to play a central role in the onset and the progression of DN. Recent evidence has emerged in the last decade to suggest uric acid is an inflammatory factor and may play a role in endothelial dysfunction. This has lead our group and others to explore the role of uric acid in the onset and progression of DN. In this review, we will highlight some of the animal and human studies that implicate uric acid in DN. Based on the evidence we review, we conclude the need for properly planned randomized controlled studies to lower uric acid levels and assess the impact of such therapy on diabetic kidney disease. PMID:22000654

Jalal, Diana I.; Maahs, David M; Hovind, Peter; Nakagawa, Takahiko

2011-01-01

73

Uric Acid and Incident Kidney Disease in the Community  

Microsoft Academic Search

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

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

2008-01-01

74

The Independent Impact of Congestive Heart Failure Status and Diuretic Use on Serum Uric Acid Among Men with a High Cardiovascular Risk Profile: A Prospective Longitudinal Study  

PubMed Central

Objective To evaluate the independent impact of congestive heart failure (CHF) status (compensation or decompensation) on serum uric acid levels among men with high cardiovascular risk profile. Method We analyzed 11,681 men from the Multiple Risk Factor Interventional Trial, using data prospectively collected at baseline and annually over 6 years (64,644 visits). We evaluated the impact of change in CHF status during study follow-up, as compared with study baseline, on hyperuricemia (serum uric acid ?7 mg/dL) and serum uric acid levels, using generalized estimating equations, adjusting for age, race, weight, weight change, education, alcohol intake, diuretic use, hypertension, serum creatinine level, and dietary factors. Similarly, we evaluated the independent impact of change in diuretic use (initiation or discontinuation). Results At baseline, mean serum uric acid was 6.88 mg/dL. Compared with no change in CHF status, odds ratios of hyperuricemia were 1.67 (95% CI, 1.21 to 2.32) for CHF decompensation and 0.21 (95% CI, 0.08 to 0.55) for compensation. The corresponding uric acid differences were 0.41 (95% CI, 0.20 to 0.62) and ?1.00 (95% CI, ?1.72 to ?0.27), respectively. The odds ratios for initiation and discontinuation of diuretic were 3.32 (95% CI, 3.06 to 3.61) and 0.39 (95% CI, 0.35 to 0.44). Conclusions CHF decompensation and diuretic use are both independently associated with increased odds of hyperuricemia among men with a high cardiovascular risk profile, whereas CHF recovery and diuretic discontinuation are associated with substantially lower odds of hyperuricemia. PMID:21435695

Misra, Devyani; Zhu, Yanyan; Zhang, Yuqing; Choi, Hyon K.

2014-01-01

75

Urea recycling in muskrats (Ondatra zibethicus): a potential nitrogen-conserving tactic?  

PubMed

The rate of 14C-urea hydrolysis was determined in 32 field-acclimatized muskrats maintained on natural diets during spring, summer, fall, and winter. We hypothesized that urea recycling occurs in muskrats during all seasons and that the conservation of tissue nitrogen via this mechanism is most prevalent in fall and winter, when forage protein levels are lowest. Muskrats exhibited higher rates of urea hydrolysis and a lower serum urea nitrogen-to-creatinine ratio in fall and winter than in spring and summer. Even after correcting for seasonal differences in blood urea pool size, the adjusted rate of urea hydrolysis was 67% higher in fall and winter than in spring and summer. There was no evidence that the maintenance nitrogen requirements of muskrats fed natural vegetation were affected by seasonal changes in the amino acid composition of the diet. We suggest that increased levels of urea recycling, coupled with adaptive mechanisms for reducing nitrogen excretion and possibly conserving carbon skeletons of essential amino acids, may allow muskrats to reduce their nitrogen requirements on fall and winter diets. Our finding that 14C-urea hydrolysis occurred during all four sampling periods suggests that nitrogen derived from this source may also be critical to supporting large hindgut microbe populations that enable this rodent to exploit the appreciable fiber content of its aquatic plant diet throughout the year. PMID:9231395

Campbell, K L; MacArthur, R A

1997-01-01

76

Compact optical microfluidic uric acid analysis system.  

PubMed

We designed, fabricated and tested a novel compact fluorescence analysis system for quantification of uric acid (UA) in clinical samples at the point-of-care. To perform an analysis, diluted saliva, urine or blood samples are simply placed in a disposable thin-film sample holder using a dropper. A new enzyme immobilization technique was developed to retain within the sample holder two enzymes and a molecule, which transforms into a fluorescer in amounts depending on the UA concentration. The small instrument (7.5 cm × 5 cm × 5 cm) into which the sample holder is placed for analysis contains an LED, a narrow-band filter and an amplified photodiode. The analysis time is 30s, and the dynamic range of the system is 4-400 ?M of UA. The calibration curve for transparent saliva and urine was made using solutions of UA. The calibration curve for opaque blood was obtained with spiked samples of blood. The three different types of clinical samples were collected from three subjects and simply diluted before their measurements. Analysis with our instrument yielded UA concentrations within the expected concentration ranges. Development of instruments based on the current laboratory prototype is expected to result in products for clinical trials and point-of-care. PMID:21549587

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

2011-06-15

77

Simultaneous determination of creatine and creatinine using amperometric biosensors.  

PubMed

In order to determine creatine and creatinine amperometric biosensors were proposed. A bienzymatic biosensor based on creatinase (CI) and sarcosine oxidase (SO) was used for the assay of creatine and a trienzymatic biosensor based on CI, SO and creatininase (CA) for the assay of creatinine. The linear concentration ranges are of pmol l(-1) to nmol l(-1) magnitude order, with very low limits of detection. The biosensors proved high reliability for determination of creatine and creatinine as raw material, and in the pharmaceutical formulation. PMID:18969149

Stefan, Raluca-Ioana; Bokretsion, Rahel Girmai; van Staden, Jacobus F; Aboul-Enein, Hassan Y

2003-08-29

78

Chemiresistor urea sensor  

DOEpatents

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

Glass, R.S.

1997-12-16

79

Uric acid as a CNS antioxidant.  

PubMed

Oxidative damage is a consistent finding in a number of central nervous system (CNS) disorders. Uric acid (UA) is a potent hydrophilic antioxidant that is modified by diet and drug. Several lines of evidence suggest that plasma UA may modulate outcomes in neurologic disease, but little attention has been paid to CNS levels of UA. Our objective was to test the hypothesis that cerebrospinal fluid (CSF) UA is determined by plasma UA, modified by blood-brain barrier (BBB) integrity and associated with rate of cognitive decline in Alzheimer's disease (AD). Also, since UA and ascorbic acid may act as antioxidants for one another, we also explored a potential interaction between them in the brain. Thirty-two patients with mild to moderate AD (Mini-Mental Status Exam 19 +/- 5) participated in a longitudinal biomarker study for one year involving standardized clinical assessments. CSF and blood were collected at baseline for UA, ascorbic acid, and albumin. Cognitive measures were collected at baseline and again one year later. CSF UA was independent of age, gender, and AD severity. CSF and plasma UA were positively correlated (r=0.669, p=0.001) and BBB impairment was associated with higher CSF levels of UA (p=0.028). Neither plasma nor CSF UA reached significant association with rates of cognitive decline over 1 year. CSF UA and CSF ascorbic acid were positively correlated (r=0.388, p=0.001). The hypothesis that CSF UA is determined by plasma UA and BBB integrity is supported, as is the hypothesis that UA and ascorbic acid are associated in CSF but not plasma. Adequately powered prospective studies would help assess any role for UA in primary and secondary prevention of AD. PMID:20061611

Bowman, Gene L; Shannon, Jackilen; Frei, Balz; Kaye, Jeffrey A; Quinn, Joseph F

2010-01-01

80

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

PubMed Central

Increased serum uric acid (SUA) levels may be involved in the development of non-alcoholic fatty liver disease (NAFLD) in men presenting with metabolic syndrome (MetS) and/or insulin resistance. We aimed to determine the independent relationship between SUA and NAFLD in non-diabetic Chinese male population, and to explore the determinants of SUA levels among indexes of adiposity, lipid, and genotypes pertaining to triglycerides metabolism, inflammation, oxidative stress, and SUA concentrations. A total of 1440 men, classified depending on the presence of ultrasonographically detected NAFLD, underwent a complete healthy checkup program. Genotypes were extracted from our previously established genome-wide association study database. After adjusting for age, smoking, drinking, body mass index, homeostasis model assessment of insulin resistance, C-reactive protein, creatinine, alanine aminotransferase (ALT) and components of metabolic syndrome, the odds ratio for NAFLD, comparing the highest with the lowest SUA quartile, was 2.81 (95% confidence interval 1.66–4.76). A stepwise multivariate linear regression analysis (R2?=?0.238, P<0.001) retained age, waist circumference, serum creatinine, triglycerides, the Q141K variant in ABCG2 (rs2231142) and NAFLD as significant predictors of SUA levels (all P<0.001). Besides, ALT and Met196Arg variant in TNFRSF1B (rs1061622) additionally associated with SUA among individuls with NAFLD. Our data suggest that in Chinese men, elevated SUA is significantly associated with NAFLD, independent of insulin resistance and other metabolic disorders, such as central obesity or hypertriglyceridemia. Meanwhile, among subjects with NAFLD, index of liver damage, such as elevated ALT combined with genetic susceptibility to inflammation associated with increased SUA levels. PMID:23935829

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

2013-01-01

81

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

PubMed

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, 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). Additional studies showed that during life impaired renal function occurred in half of these subjects. 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. Indeed, gout was removed from the textbooks as a cause of CKD, and the common association of hyperuricemia with CKD was solely attributed to the retention of serum uric acid that is known to occur as the glomerular filtration rate falls. Renewed interest in uric acid as a cause of CKD occurred when it was realized that invalid assumptions had been made in the arguments to dismiss uric acid as a risk factor for CKD. The greatest assumption was that the mechanism by which uric acid would cause kidney disease would be via the precipitation as crystals in the kidney, similar to the way it causes gout. However, when laboratory animals with CKD were made hyperuricemic, the renal disease progressed rapidly despite an absence of crystals in the kidney. Since this seminal study, there has been a renewed interest in the potential role uric acid may have in both acute and CKD. We briefly review some of the major advances that have occurred in this field in the last 15 years. PMID:23543594

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

2013-09-01

82

Hydroxyproline and creatinine levels in normal amniotic fluid  

Microsoft Academic Search

Summary  Total hydroxyproline and creatinine concentrations as well as their ratios were determined in 29 amniotic fluid samples from\\u000a normal pregnancies between the 16th and 20th week of gestation. Total hydroxyproline and creatinine levels, and their ratios,\\u000a were not statistically different considering either the values at each week or those of the whole 5-week period. Our results,\\u000a compared with the few

Rosario Troccoli; Carlo Stella; Antonio Pachì; Michele Ermini; Stefano Biagioni; Serafina Battistelli; Francesco Stella; Ferdinando Mannello; Francesco Marcheggiani

1986-01-01

83

Uric Acid Nephrolithiasis: Recent Progress and Future Directions  

PubMed Central

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

Ngo, Tin C; Assimos, Dean G

2007-01-01

84

Renal Transport of Uric Acid: Evolving Concepts and Uncertainties  

PubMed Central

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

Bobulescu, Ion Alexandru; Moe, Orson W.

2013-01-01

85

Reference Ranges for Serum Uric Acid among Healthy Assamese People  

PubMed Central

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

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

2014-01-01

86

Association between intronic SNP in urate-anion exchanger gene, SLC22A12, and serum uric acid levels in Japanese.  

PubMed

Serum uric acid levels are maintained by urate synthesis and excretion. URAT1 (coded by SLC22CA12) was recently proposed to be the major absorptive urate transporter protein in the kidney regulating blood urate levels. Because genetic background is known to affect serum urate levels, we hypothesized that genetic variations in SLC22A12 may predispose humans to hyperuricemia and gout. We investigated rs893006 polymorphism (GG, GT and TT) in SLC22A12 in a total of 326 Japanese subjects. Differences in clinical characteristics among the genotype groups were tested by the analysis of variance (ANOVA). In male subjects, mean serum uric acid levels were significantly different among the three genotypes. Levels in the GG genotype subjects were the highest, followed by those with the GT and TT genotypes. However, no differences between the groups were seen in the distributions of creatinine, Fasting plasma glucose (FPG), HbA(1c), total cholesterol, triglyceride, HDL cholesterol levels or BMI. A single nucleotide polymorphism (SNP) in the urate transporter gene SLC22CA12 was found to be associated with elevated serum uric acid levels among Japanese subjects. This SNP may be an independent genetic marker for predicting hyperuricemia. PMID:16920156

Shima, Yukio; Teruya, Koji; Ohta, Hidehiko

2006-11-01

87

Creatinine corrections for estimating children's and adult's pesticide intake doses in equilibrium with urinary pesticide and creatinine concentrations  

Microsoft Academic Search

A urine contaminant concentration per se has uncertain meaning for human health because of dilution by hydration. However, the estimation of the health-related daily intake dose of pollutant (mg\\/kg\\/day) that equilibrates with a spot urinary concentration of a pesticide residue or metabolite, or other analyte, can be made using creatinine-corrected toxicant levels (mg analyte\\/mg creatinine) multiplied by an estimate of

David T Mage; Ruth H Allen; Anuradha Kodali

2008-01-01

88

Urea and amphibian water economy.  

PubMed

Accumulation of urea in the body fluids enables some amphibians to tolerate high ambient salinities (Bufo viridis, Xenopus laevis, Rana cancrivora, Ambystoma tigrinum, Batrachoseps spp.) or to estivate in soil with low water potentials (Scaphiopus spp.). These species are assumed not only to accumulate urea produced in the normal metabolism, but to synthesize urea in response to water shortage. Re-examination of the data did not support the view of an osmoregulatory urea synthesis. Increased urea synthesis on exposure to high salinities in X. laevis, R. cancrivora and Batrachoseps spp. seemed to reflect reactions to an adverse environment. It is suggested that in amphibians, solute concentration in the plasma and rate of excretion of urea are coordinated so that at a certain plasma concentration, urea is excreted at the same rate at which it is produced. The higher the level of urea in the body fluids at balance between production and excretion, the higher the tolerance of the species of low external water potentials. The mechanisms that integrate the relationship between plasma solute concentration and handling of urea by the kidneys are not known. PMID:9172374

Jørgensen, C B

1997-06-01

89

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

PubMed Central

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. PMID:25202361

TAKAI, MIHOKO; YAMAUCHI, TAKAHIRO; FUJITA, KEI; LEE, SHIN; OOKURA, MIYUKI; KISHI, SHINJI; URASAKI, YOSHIMASA; YOSHIDA, AKIRA; IWASAKI, HIROMICHI; UEDA, TAKANORI

2014-01-01

90

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

Microsoft Academic Search

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

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

2010-01-01

91

SERS quantitative urine creatinine measurement of human subject  

NASA Astrophysics Data System (ADS)

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

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

2005-03-01

92

Critical Serum Creatinine Values in Very Preterm Newborns  

PubMed Central

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

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

2013-01-01

93

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,...

94

Chronic Hyperuricemia, Uric Acid Deposit and Cardiovascular Risk  

PubMed Central

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

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

2013-01-01

95

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

PubMed Central

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

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

2013-01-01

96

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

PubMed

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

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

2013-10-01

97

Serum Uric Acid Levels Are Associated with Polymorphism in the SAA1 Gene in Chinese Subjects  

PubMed Central

Objective Serum uric acid (SUA) is a cardiovascular risk marker associated with inflammation. The serum amyloid A protein (SAA) is an inflammatory factor and is associated with cardiovascular disease (CVD). However, the relationship between genetic polymorphisms of SAA and SUA levels has not been studied. The objective of this study was to investigate the association between SUA levels and SAA genetic polymorphisms. Methods All participants were selected from subjects participating in the Cardiovascular Risk Survey (CRS) study. The single nucleotide polymorphism (SNP) rs12218 of the SAA1 gene was genotyped by using the polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) method. The association of SUA levels with genotypes was assessed by using the general liner mode. Results The SNP rs12218 was associated with SUA levels by analyses of a dominate model (P?=?0.002) and additive model (P?=?0.005), and the difference remained significant after adjustment of sex, age, obesity, ethnicity, HDL-C, alcohol intake, smoking, and creatinine (P?=?0.006 and P?=?0.023, respectively). The TT genotype was associated with an increased SUA concentration of 39.34 mmol/L (95% confidence interval [CI], 3.61–75.06, P?=?0.031) compared with the CC genotype, and the TT genotype was associated with an increased SUA concentration of 2.48 mmol/L (95% CI, 6.86–38.10; P?=?0.005) compared with the CT genotype. Conclusions The rs12218 SNP in the SAA1 gene was associated with SUA levels in Chinese subjects, indicating that carriers of the T allele of rs12218 have a high risk of hyperuricemia. PMID:22768267

Xie, Xiang; Ma, Yi-Tong; Yang, Yi-Ning; Li, Xiao-Mei; Fu, Zhen-Yan; Zheng, Ying-Ying; Ma, Xiang; Chen, Bang-Dang; Liu, Fen; Huang, Ying; Yu, Zi-Xiang; Chen, You

2012-01-01

98

Uric acid level increases in humans engaged in gambling: a preliminary report.  

PubMed

The effect of gambling and gaming on plasma levels of uric acid was studied. Blood samples were obtained from normal subjects while they gambled for money or while they played checkers without betting. There was an interaction of time and activity reflecting primarily an association of increased uric acid levels during gambling over time, compared with gaming and relaxation. This indicates that gambling can increase plasma levels of uric acid. PMID:8260567

Manowitz, P; Amorosa, L F; Goldstein, H S; Carlton, P L

1993-09-01

99

Impulsivity is Associated with Uric Acid: Evidence from Humans and Mice  

PubMed Central

Background The ability to control impulses varies greatly, and difficulty with impulse control can have severe consequences; in the extreme, it is the defining feature of many psychiatric disorders. Evidence from disparate lines of research suggests that uric acid is elevated in psychiatric disorders characterized by high impulsivity, such as ADHD and bipolar disorder. The present research tests the hypothesis that impulsivity is associated with higher uric acid in humans and mice. Methods Using two longitudinal, non-clinical community samples (total N=6883), we test whether there is an association between uric acid and normal variation in trait impulsivity measured with the Revised NEO Personality Inventory. We also examined the effect of uric acid on behavior by comparing wild-type mice (WT), which naturally have low levels of uric acid, to mice genetically modified (UOX) to accumulate high levels of uric acid. Results In both human samples, the emotional aspects of trait impulsivity, specifically Impulsiveness and Excitement-Seeking, were associated with higher levels of uric acid concurrently and when uric acid was measured 3–5 years later. Consistent with the human data, the UOX mice displayed significantly more exploratory and novelty-seeking behavior than the WT mice. Conclusion Higher uric acid was associated with impulsivity in both humans and mice. The identification of biological markers of impulsivity may lead to a better understanding of the physiological mechanisms involved in impulsivity, and may suggest potential targets for therapeutic intervention. PMID:23582268

Sutin, Angelina R.; Cutler, Roy G.; Camandola, Simonetta; Uda, Manuela; Feldman, Neil H.; Cucca, Francesco; Zonderman, Alan B.; Mattson, Mark P.; Ferrucci, Luigi; Schlessinger, David; Terracciano, Antonio

2013-01-01

100

Pro-inflammatory effects of uric acid in the gastrointestinal tract  

PubMed Central

Uric acid can be generated in the gastrointestinal (GI) tract from the breakdown of nucleotides ingested in the diet or from purines released from host cells as a result of pathogen-induced cell damage. Xanthine oxidase (XO) is the enzyme that converts hypoxanthine or xanthine into uric acid, a reaction that also generates hydrogen peroxide. It has been assumed that the product of XO responsible for the pro-inflammatory effects of this enzyme is hydrogen peroxide. Recent literature on uric acid, however, has indicated that uric acid itself may have biological effects. We tested whether uric acid itself has detectable pro-inflammatory effects using an in vivo model using ligated rabbit intestinal segments (“loops”) as well as in vitro assays using cultured cells. Addition of exogenous uric acid increased the influx of heterophils into rabbit intestinal loops, as measured by myeloperoxidase activity. In addition, white blood cells adhered avidly to uric acid crystals, forming large aggregates of cells. Uric acid acts as a leukocyte chemoattractant in the GI tract. The role of uric acid in enteric infections and in non-infectious disorders of the GI tract deserves more attention. PMID:24377830

Crane, John K.; Mongiardo, Krystin M.

2014-01-01

101

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

102

Importance of creatinine clearance for drug dosing in nursing home residents.  

PubMed

Serum creatinine is often not an adequate measure of renal function, especially in advanced age or in physically debilitated patients. Estimated creatinine clearance is necessary to decide on usage of drugs such as Metformin. This study included 64 nursing home residents with diabetes treated with Metformin. Creatinine clearance (CrCl) was calculated by the Cockcroft-Gault equation modified for ideal body weight. CrCl more than or equal to 60/mL min was used as a cut-off for appropriate use of Metformin. In our sample, 20.3% had renal failure when measured by serum creatinine while 56.3% had renal failure when measured by CrCl. Age >65 years and women were more likely to be classified as normal for serum creatinine but have abnormal creatinine clearance. Use of estimated creatinine clearance should be advocated instead of serum creatinine when prescribing Metformin, especially for those of older age and among women. PMID:24111696

Shah, Jignesh; Fogel, Joshua; Balsam, Leah

2014-02-01

103

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

E-print Network

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

Mandelbaum, Tal

104

A model to predict 24-h urinary creatinine using repeated measurements in an occupational cohort study  

Microsoft Academic Search

Creatinine measurements can be used to standardize urinary pesticide concentrations and to estimate “completeness” of urine collections. Published statistical models exist to predict 24-h creatinine, but many were developed assuming independence among observations. Using correlated repeated measurement data collected from an occupational cohort, the objectives were to create a predictive model for 24-h urinary creatinine and to compare the predictive

Donna S Kroos; James E Mays; Shelley A Harris

2010-01-01

105

Impact of serum creatinine measurement error on dose adjustment in renal failure  

Microsoft Academic Search

Background: Doses of renally eliminated drugs should be adjusted according to kidney function to prevent adverse drug events and cost. Dose adjustment can be based on serum creatinine level, subsequent creatinine clearance estimation, and dosage calculation with consideration of the renal elimination properties of the respective compound.Objective: Our objective was to quantify the impact and relevance of serum creatinine measurementerror

Verena Schneider; Volkmar Henschel; Keyvan Tadjalli-Mehr; Ulrich Mansmann; Walter E. Haefeli

2003-01-01

106

Contribution of uric acid to cancer risk, recurrence, and mortality  

PubMed Central

Two risk factors for the development and progression of cancers that are amenable to life style modification are chronic inflammation and the metabolic syndrome. This review proposes two new targets that may mechanistically integrate inflammation and metabolic syndrome, have been largely ignored, and are known to be druggable. Recent evidence has demonstrated that elevated serum uric acid (hyperuricemia) is associated with excess cancer risk, recurrence, and mortality. Although uric acid (UA) can function as a systemic antioxidant, its pro-inflammatory properties have been postulated to play an important role in the pathogenesis of cancer. Furthermore, obesity, Type 2 Diabetes Mellitus (T2DM), and the metabolic syndrome (MetS) are also associated with excess cancer, chronic inflammation, and with hyperuricemia, suggesting that UA may represent an important link between these disorders and the development of cancer. While pharmacological modulation of hyperuricemia could in principal augment anti-cancer therapeutic strategies, some cancer cells express low intracellular levels of the enzyme Xanthine Oxidoreductase (XOR) that are associated with increased cancer aggressiveness and poor clinical outcome. Thus, systemic pharmacological inhibition of XOR may worsen clinical outcome, and specific strategies that target serum uric acid (SUA) without inhibiting tumor cell XOR may create new therapeutic opportunities for cancer associated with hyperuricemia. This review will summarize the evidence that elevated SUA may be a true risk factor for cancer incidence and mortality, and mechanisms by which UA may contribute to cancer pathogenesis will be discussed in the hope that these will identify new opportunities for cancer management. PMID:23369448

2012-01-01

107

Contribution of uric acid to cancer risk, recurrence, and mortality.  

PubMed

Two risk factors for the development and progression of cancers that are amenable to life style modification are chronic inflammation and the metabolic syndrome. This review proposes two new targets that may mechanistically integrate inflammation and metabolic syndrome, have been largely ignored, and are known to be druggable. Recent evidence has demonstrated that elevated serum uric acid (hyperuricemia) is associated with excess cancer risk, recurrence, and mortality. Although uric acid (UA) can function as a systemic antioxidant, its pro-inflammatory properties have been postulated to play an important role in the pathogenesis of cancer. Furthermore, obesity, Type 2 Diabetes Mellitus (T2DM), and the metabolic syndrome (MetS) are also associated with excess cancer, chronic inflammation, and with hyperuricemia, suggesting that UA may represent an important link between these disorders and the development of cancer. While pharmacological modulation of hyperuricemia could in principal augment anti-cancer therapeutic strategies, some cancer cells express low intracellular levels of the enzyme Xanthine Oxidoreductase (XOR) that are associated with increased cancer aggressiveness and poor clinical outcome. Thus, systemic pharmacological inhibition of XOR may worsen clinical outcome, and specific strategies that target serum uric acid (SUA) without inhibiting tumor cell XOR may create new therapeutic opportunities for cancer associated with hyperuricemia. This review will summarize the evidence that elevated SUA may be a true risk factor for cancer incidence and mortality, and mechanisms by which UA may contribute to cancer pathogenesis will be discussed in the hope that these will identify new opportunities for cancer management. PMID:23369448

Fini, Mehdi A; Elias, Anthony; Johnson, Richard J; Wright, Richard M

2012-01-01

108

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

PubMed

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

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

2012-01-01

109

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

PubMed Central

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

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

2012-01-01

110

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

PubMed Central

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

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

111

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

PubMed Central

Objective Uric acid is the end product of purine metabolism in humans, and increased serum uric acid concentrations lead to gout. The objective of the current study was to identify factors that are independently associated with serum uric acid concentrations in a cohort of Czech control individuals. Methods The cohort consisted of 589 healthy subjects aged 18–65 years. We studied the associations between the serum uric acid concentration and the following: (i) demographic, anthropometric and other variables previously reported to be associated with serum uric acid concentrations; (ii) the presence of metabolic syndrome and the levels of metabolic syndrome components; and (iii) selected genetic variants of the MTHFR (c.665C>T, c.1286A>C), SLC2A9 (c.844G>A, c.881G>A) and ABCG2 genes (c.421C>A). A backward model selection procedure was used to build two multiple linear regression models; in the second model, the number of metabolic syndrome criteria that were met replaced the metabolic syndrome-related variables. Results The models had coefficients of determination of 0.59 and 0.53. The serum uric acid concentration strongly correlated with conventional determinants including male sex, and with metabolic syndrome-related variables. In the simplified second model, the serum uric acid concentration positively correlated with the number of metabolic syndrome criteria that were met, and this model retained the explanatory power of the first model. Moderate wine drinking did not increase serum uric acid concentrations, and the urate transporter ABCG2, unlike MTHFR, was a genetic determinant of serum uric acid concentrations. Conclusion Metabolic syndrome, moderate wine drinking and the c.421C>A variant in the ABCG gene are independently associated with the serum uric acid concentration. Our model indicates that uric acid should be clinically monitored in persons with metabolic syndrome. PMID:24827988

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

2014-01-01

112

Hyperfiltration Affects Accuracy of Creatinine eGFR Measurement  

PubMed Central

Summary Background and objectives Surrogate markers such as creatinine, cystatin C (CysC), and beta trace protein (BTP) have been used to estimate GFR (eGFR). The accuracy of eGFR may be altered with hyperfiltration and differences in filtration fraction (FF). It is hypothesized that the accuracy of creatinine for eGFR may be affected by hyperfiltration and different effective renal plasma flow (ERPF). Design, setting, participants, & measurements A total of 127 pediatric patients with various renal diseases underwent simultaneous measurements of GFR using 51Cr-EDTA renal scan and ERPF (131I-hippurate clearance) to calculate the FF (FF = GFR/ERPF). The eGFRs were calculated using the commonly used Schwartz (creatinine), Filler (CysC), and Benlamri (BTP) formulas. Agreement of the eGFRs with the measured isotope GFRs was assessed by Bland–Altman plots. Correlation analysis was performed using nonparametric tests to compare FF with eGFR ? GFR. Results The 127 children at a median age (with 25th percentile, 75th percentile) of 11.9 (8.5, 14.9) years had a mean 51Cr EDTA-GFR of 100.6 ± 32.1 ml/min per 1.73 m2 and a median 131I-hippurate clearance (ERPF) of 588 (398,739) ml/min per 1.73 m2. Mean FF was 17.7 ± 4.5% with no correlation between the FF and the error (eGFR ? GFR) for CysC and BTP eGFR, whereas there was a significant negative correlation between the error for Schwartz eGFR and FF. Conclusions There is a significant negative correlation between the error for the Schwartz eGFR and the FF. CysC and BTP are not affected by differences in FF. PMID:20966120

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

2011-01-01

113

Urea Biosynthesis Using Liver Slices  

ERIC Educational Resources Information Center

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

Teal, A. R.

1976-01-01

114

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

Microsoft Academic Search

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

EVS Prakasa Rao; Munnu Singh; Narayana; G Chandrasekhara

1984-01-01

115

Phytotoxicity of foliar-applied urea  

PubMed Central

Recent work in our laboratory showed that the adverse effect of urea fertilizer on seed germination and seedling growth in soil is due to ammonia produced through hydrolysis of urea by soil urease (NH2CONH2 + H2O ? 2NH3 + CO2) and can be eliminated by amending the fertilizer with a small amount of a urease inhibitor such as phenylphosphorodiamidate. Because the leaf-tip necrosis often observed after foliar fertilization of plants with urea is usually attributed to ammonia formed through hydrolysis of urea by plant urease, we studied the possibility that this necrosis could be eliminated or reduced by adding phenylphosphorodiamidate to the urea fertilizer. We found that, although addition of this urease inhibitor to foliar-applied urea increased the urea content and decreased the ammonia content and urease activity of soybean [Glycine max. (L.) Merr.] leaves fertilized with urea, it increased the leaf-tip necrosis observed after fertilization. We conclude that this necrosis resulted from accumulation of toxic amounts of urea rather than from formation of toxic amounts of ammonia. This conclusion was supported by our finding that the necrotic areas of soybean leaves treated with urea or with urea and phenylphosphorodiamidate contained much higher concentrations of urea than did the nonnecrotic areas. Images PMID:16594077

Krogmeier, Michael J.; McCarty, Gregory W.; Bremner, John M.

1989-01-01

116

40 CFR 721.9892 - Alkylated urea.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Alkylated urea. 721.9892 Section 721.9892 ...Chemical Substances § 721.9892 Alkylated urea. (a) Chemical substance and significant...substance identified generically as an alkylated urea (PMN P-93-1649) is subject to...

2010-07-01

117

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

PubMed Central

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

Kang, Duk-Hee

2014-01-01

118

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

PubMed Central

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

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

2014-01-01

119

Urea biosensor for hemodialysis monitoring  

DOEpatents

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

Glass, Robert S. (Livermore, CA)

1999-01-01

120

Urea biosensor for hemodialysis monitoring  

DOEpatents

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

Glass, R.S.

1999-01-12

121

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

122

Uric acid concentrations are associated with insulin resistance and birthweight in normotensive pregnant women  

PubMed Central

OBJECTIVE To investigate whether uric acid concentrations are increased in pregnant women with insulin resistance and to correlate both with fetal growth. STUDY DESIGN Uric acid, glucose and insulin were measured in plasma at 20.4 (± 2.0) weeks gestation in 263 women. The association between uric acid and insulin resistance as estimated using the homeostasis model assessment (HOMA) was analyzed and related to birthweights. RESULTS In 212 (80.6%) women who remained normotensive throughout pregnancy, HOMA increased 1.23 units per 1 mg/dl increase in uric acid [(95%CI: 1.07,1.42), p=0.003]. Infants born to normotensive women in the upper quartile of uric acid and lowest HOMA quartile weighed 435.6 grams less than infants of women with highest uric acid and HOMA quartiles (p < 0.005). CONCLUSION Increasing uric acid concentrations were associated with insulin resistance in mid-pregnancy. Hyperuricemia was associated with lower birthweight in normotensive women, and this effect was attenuated by insulin resistance. PMID:19729142

LAUGHON, S. Katherine; CATOV, Janet; ROBERTS, James M.

2009-01-01

123

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

PubMed Central

Many biologic functions follow circadian rhythms driven by internal and external cues that synchronize and coordinate organ physiology to diurnal changes in the environment and behavior. Urinary acid-base parameters follow diurnal patterns and it is thought these changes are due to periodic surges in gastric acid secretion. Abnormal urine pH is a risk factor for specific types of nephrolithiasis and uric acid stones are typical of excessively low urine pH. Here we placed 9 healthy volunteers and 10 uric acid stone formers on fixed metabolic diets to study the diurnal pattern of urinary acidification. All showed clear diurnal trends in urinary acidification but none of the patterns were affected by inhibitors of the gastric proton pump. Uric acid stone formers had similar patterns of change through the day but their urine pH was always lower compared to healthy volunteers. Uric acid stone formers excreted more acid (normalized to acid ingestion) with the excess excreted primarily as titratable acid rather than ammonium. Urine base excretion was also lower in uric acid stone formers (normalized to base ingestion) along with lower plasma bicarbonate concentrations during part of the day. Thus, increased net acid presentation to the kidney and the preferential use of buffers, other than ammonium, result in much higher concentrations of un-dissociated uric acid throughout the day and consequently an increased risk of uric acid stones. PMID:22297671

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

2012-01-01

124

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

PubMed

Increased serum uric acid has been identified as an independent risk factor for cardiovascular disease. However, because of its antioxidant capacity, uric acid may play a beneficial role in endothelial function. This paradoxical relationship between uric acid and endothelial function in chronic heart failure patients remains poorly understood. Thirty-eight chronic heart failure patients (New York Heart Association functional class II-III, mean age 58+/-10 years and mean left ventricular ejection fraction 25+/-8%) and twelve age-and-sex-matched healthy controls were studied. Chronic heart failure patients showed higher uric acid levels (7.3+/-2.3 mg/dL vs. 6.1+/-0.2 mg/dL, p<0.05) and lower extracellular superoxide dismutase activity (136+/-36 U ml(-1) min(-1) vs. 203+/-61 U ml(-1) min(-1), p<0.01) and endothelium-dependent vasodilatation (4.0+/-1.6% v. 9.1+/-3.0%, p<0.01) when compared with control subjects. In chronic heart failure patients, correlations between both uric acid levels and extracellular superoxide dismutase activity (r=0.45; p<0.01), and uric acid and endothelium-dependent vasodilatation (r=0.35; p=0.03) were detected. These correlations were not observed in healthy individuals, suggesting a positive effect of uric acid on endothelial function partially mediated by modulation of extracellular superoxide dismutase activity in chronic heart failure. PMID:18559296

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

2008-07-01

125

Possibilities and limitations in miniaturized sensor design for uric acid.  

PubMed

Uric acid (UA) has been under intensive investigation by electrochemists owing to its important role as a metabolite in biological fluids. One of the major problems in biological determinations of uric acid comes from electrochemical interferences such as ascorbic acid (AA), which has a similar oxidation potential, E1/2 approximately 200 mV versus SCE, at graphite electrodes, and is present at high concentrations in biological systems. UA undergoes a 2 H+, 2 e- oxidation in aqueous buffers. The oxidation product, a diimine, is an unstable intermediate with a half-life of less than 22 ms. A follow-up hydration reaction converts the diimine to an imine alcohol. Results of previous work show that UA weakly adsorbs and undergoes a fast electron transfer reaction, ks = 54 s-1, at carbon fiber electrodes. These characteristics make UA an excellent candidate for fast scan voltammetric (FSV) determinations. This paper presents the results of FSV at bare carbon fiber electrodes. The results show good selectivity and sensitivity in the determination of low concentrations of UA in the presence of high concentrations of AA. By increasing the scan rate above 500 V s-1, voltammograms of UA in the presence of AA can be resolved because of the kinetic differences in the response of the two anions, without the need for a permselective film on the electrode. Results are also presented that demonstrate an effective way to reach a stable background current at bare carbon fiber electrodes, which is required in FSV because the signal from the analyte is smaller than the electrochemical signal from the background current. Signal-to-noise ratios at bare carbon fiber electrodes in FSV are improved, because the high temporal resolution in fast scan methods allows the acquisition of a large number of scans that can be signal averaged in a short period of time. In addition, large signals can be measured because the voltammetric peak current increases with increase in scan rate. PMID:9830175

Bravo, R; Hsueh, C C; Jaramillo, A; Brajter-Toth, A

1998-07-01

126

Uric acid as radical scavenger and antioxidant in the heart.  

PubMed

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

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

1989-11-01

127

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

PubMed Central

Unlike experimental studies indicating a neuroprotective property of uric acid, clinical studies have shown that elevated levels of uric acid are associated with a risk of ischemic stroke. However, the association of uric acid with cerebral hemorrhage has seldom been tested. We aimed to elucidate the association between uric acid and cerebral microbleeds (CMBs), a hemorrhage-prone cerebral microangiopathy. Seven hundred twenty-four patients with ischemic stroke who were consecutively admitted to our hospital were included in this study. We collected demographic, clinical, and laboratory data, including uric acid level, and examined the presence of CMBs using T2*-weighted gradient-echo MRI. We used logistic regression analysis to examine an independent association between uric acid and CMBs. Two-hundred twenty-six patients had CMBs (31.2%). After adjusting for possible confounders, elevated uric acid was independently associated with the presence of CMBs (the highest quartile vs. lowest quartile, adjusted odd ratio [OR], 1.98; 95% confidence interval [CI], 1.16–3.39). This association retained in patients with deep or infratentorial CMBs (with or without lobar CMBs) but not among those with lobar CMBs. In addition, this association was robust among patients with hypertension (the highest quartile vs. lowest quartile, adjusted OR, 2.74; 95% CI, 1.43–5.24). In contrast, we did not find the association in patients without hypertension. We demonstrated that serum uric acid is independently associated with the presence of CMBs. In particular, the relation between uric acid and CMBs was robust in hypertensive patients. PMID:23372838

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

2013-01-01

128

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

PubMed Central

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

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

2014-01-01

129

Urea Transformation of Wetland Microbial Communities  

Microsoft Academic Search

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

Ann-Karin Thorén

2007-01-01

130

Uric Acid Spherulites in the Reflector Layer of Firefly Light Organ  

PubMed Central

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

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

2013-01-01

131

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

PubMed

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 ZnO? 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 ZnO? nanoparticles and constructed in a 1×3 array configuration (UAB-1×3-ZnO?) demonstrated enough sensitivity (9.4 ?A/mM) for quantifying uric acid extracted by the combined physical forces of laser, electroporation, and RI. A good linear relationship (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-ZnO?. In conclusion, a new approach to noninvasive transdermal extraction and quantification of uric acid has been established. PMID:25061289

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

2014-01-01

132

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

PubMed Central

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

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

2014-01-01

133

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

Microsoft Academic Search

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

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

2004-01-01

134

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

Microsoft Academic Search

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

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

2003-01-01

135

Association of uric Acid genetic risk score with blood pressure: the rotterdam study.  

PubMed

High levels of serum uric acid are associated with hypertension in observational studies. The aim of this study was to investigate the association of uric acid gene variants with blood pressure. We studied 5791 participants aged ?55 years from the Rotterdam Study. Thirty gene variants identified for serum uric acid level were used to compile genetic risk score (GRS). We used linear regression models to investigate the association of the uric acid GRS with systolic and diastolic blood pressure in the whole study population and separately in participants with and without comorbidities and medication use. In the age- and sex-adjusted model, each SD increase in uric acid GRS was associated with 0.75 mm Hg lower systolic blood pressure (95% confidence interval, -1.31 to -0.19) and 0.42 mm Hg lower diastolic blood pressure (95% confidence interval, -0.72 to -0.13). The association did not attenuate after further adjustment for antihypertensive medication use and conventional cardiovascular risk factors. In subgroup analysis, the association of uric acid GRS with systolic blood pressure was significantly stronger in participants (n=885) on diuretic treatment (P for interaction, 0.007). In conclusion, we found that higher uric acid GRS is associated with lower systolic and diastolic blood pressure. Diuretics treatment may modify the association of uric acid genetic risk score and systolic blood pressure. Our study suggests that genome wide association study's findings can be associated with an intermediate factor or have a pleiotropic role and, therefore, should be applied for Mendelian Randomization with caution. PMID:25185132

Sedaghat, Sanaz; Pazoki, Raha; Uitterlinden, Andre G; Hofman, Albert; Stricker, Bruno H Ch; Ikram, M Arfan; Franco, Oscar H; Dehghan, Abbas

2014-11-01

136

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

Microsoft Academic Search

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

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

1977-01-01

137

Uric acid attenuates trophoblast invasion and integration into endothelial cell monolayers  

PubMed Central

Hyperuricemia develops as early as 10 wk of gestation in women who later develop preeclampsia. At this time the invasive trophoblast cells are actively remodeling the uterine spiral arterioles, integrating into and finally replacing the vascular endothelial lining. In the nonpregnant population uric acid has several pathogenic effects on vascular endothelium. We therefore sought to examine the effects of uric acid (0–7 mg/dl) on trophoblast cell invasion through an extracellular matrix using an in vitro Matrigel invasion assay. We also assessed trophoblast integration into a uterine microvascular endothelial cell monolayer in a trophoblast-endothelial cell coculture model. Additionally, we addressed the importance of redox signaling and trophoblast-induced endothelial cell apoptosis. Uric acid elicited a concentration-dependent attenuation of trophoblast invasion and integration into a uterine microvascular endothelial cell monolayer. The attenuated trophoblast integration appeared to be the result of reduced trophoblast-induced endothelial cell apoptosis, likely through the intracellular antioxidant actions of uric acid. In a test of relevance, pooled serum (5% vol/vol) from preeclamptic women attenuated the ability of trophoblast cells to integrate into the endothelial cell monolayers compared with pooled serum from healthy pregnant controls, and this response was partially rescued when endogenous uric acid was previously removed with uricase. Taken together these data support the hypothesis that elevations in circulating uric acid in preeclamptic women contribute to the pathogenesis of the disorder, in part, through attenuation of normal trophoblast invasion and spiral artery vascular remodeling. PMID:19535510

Bainbridge, Shannon A.; Roberts, James M.; von Versen-Hoynck, Frauke; Koch, Jessa; Edmunds, Lia; Hubel, Carl A.

2009-01-01

138

Genotype-based changes in serum uric acid affect blood pressure  

PubMed Central

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

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

2013-01-01

139

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

PubMed

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

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

2014-04-01

140

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

PubMed Central

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

Car, Sinisa; Trkulja, Vladimir

2009-01-01

141

Extraction of urea and ammonium ion  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

142

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

PubMed Central

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

Najafi, Mahdi

2014-01-01

143

40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

144

Schlieren photography study of energy absorption by uric acid nuclei.  

PubMed

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

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

2000-02-01

145

Serum uric acid is associated with coronary artery calcification.  

PubMed

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

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

2014-06-01

146

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

147

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

PubMed Central

AIM: To assess the feasibility/accuracy of a commercial handheld device in the context of increased demand for point-of-care serum creatinine (SCr) determination. METHODS: In this institutional review board-approved, prospective study, 401 patients referred for contrast-enhanced computed tomography were included at two centres. Capillary (c)SCr was determined using two devices A+B and venous (v)SCr was determined in the centre’s laboratory. Method comparison statistics for both centres and for vSCr<>1.2 mg/dL, receiver operating characteristic analysis, negative predictive values (NPV), sensitivity and specificity were calculated pre-/post-curve offset correction with vSCr. RESULTS: Pearson’s coefficients for cSCr vs vSCr were: centre 1-A:0.93/B:0.92; centre 2-A:0.85/B:0.82 (all P < 0.0001). Overall correlation was better for vSCr > 1.2 mg/dL. The area under the receiver operating characteristic curves showed a high accuracy for cSCr, but the device underestimated SCr, which was confirmed by Bland-Altman plot. Addition of the offset correction factor to the original data from centre 1 resulted in an improvement in sensitivity for detecting patients at risk (> 1.2 mg/dL), whilst maintaining acceptable specificity and improving NPV. CONCLUSION: This study showed the feasibility of SCr determination using the evaluated handheld device in a routine clinical setting. The device showed high sensitivity and high NPV, but may significantly underestimate SCr without offset correction to local laboratories. PMID:22900135

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

2012-01-01

148

Serum lipid profile and uric acid levels in preeclampsia in University of Benin Teaching Hospital  

PubMed Central

Background: Preeclampsia is a pregnancy-specific disease associated with significant maternal and perinatal mortality and morbidity. Lipid abnormality and elevated serum uric acid have been reported as early features of the disease. We aimed to detect the level of serum lipid profile and uric acid abnormalities in severe preeclamptics in Benin City and to measure their clinical significance. Materials and Methods: A prospective case-control study was conducted with subjects presenting with severe preeclampsia to the Obstetric Unit of the UBTH, Benin City. Fasting serum lipid profile and uric acid levels of 40 severe preeclamptic subjects and 80 gestation-matched normotensive controls were done at recruitment. The preeclamptic subjects were managed according to our departmental protocol which included stabilisation and delivery. Their sociodemographic and clinical characteristics were used to generate a database for analysis. Results: The mean serum uric acid level was 28% higher in severe preeclamptics than normotensive women (5.96 ± 2.54 mg/dl versus 4.30 ± 0.85; P = 0.005). There were statistically significant differences in levels of triglycerides (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) between the preeclamptics and their normotensive controls (P = 0.006, P = 0.000, P = 0.000, respectively). Abnormal serum uric acid was associated with advanced maternal age (P = 0.000), early-onset preeclampsia (P = 0.000) and abnormal body mass index (BMI; P = 0.000). Low birth weight was more likely in preeclamptics with elevated serum uric acid levels (P = 0.041). Conclusion: Abnormality of serum uric acid in preeclampsia was significantly associated with increased frequency of complications but lipid profile abnormalities were not shown in the subjects studied. We recommend a larger scale study to determine lipid profile in normal and complicated pregnancies in our environment.

Enaruna, Nosakhare O; Idemudia, Joseph O; Aikoriogie, Paul I

2014-01-01

149

Direct detection of uric acid in body fluid samples by using boron doped graphite nano particles as the working electrode.  

PubMed

Boron doped graphite nano particles were used as functioning elements for creation of electrodes for the detection of uric acid in biological samples. The electrode obtained in this manner was capable of oxidizing ascorbic acid at lower potentials. This provided a desirable solution to the interfering problem encountered in the detection of uric acid in biological samples caused by ascorbic acid. The detectable concentrations for uric acid ranged from 5.0 to 130 µM. The applicability of the electrode was experimentally demonstrated by the successful direct detection of uric acid in real urine samples. PMID:21478610

He, Jianjun; Fugetsu, Bunshi; Tanaka, Shunitz

2011-01-01

150

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

SciTech Connect

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

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

2011-11-15

151

Calcium Supplementation Increases Blood Creatinine Concentration in a Randomized Controlled Trial  

PubMed Central

Background Calcium supplements are widely used among older adults for osteoporosis prevention and treatment. However, their effect on creatinine levels and kidney function has not been well studied. Methods We investigated the effect of calcium supplementation on blood creatinine concentration in a randomized controlled trial of colorectal adenoma chemoprevention conducted between 2004–2013 at 11 clinical centers in the United States. Healthy participants (N?=?1,675) aged 45–75 with a history of colorectal adenoma were assigned to daily supplementation with calcium (1200 mg, as carbonate), vitamin D3 (1000 IU), both, or placebo for three or five years. Changes in blood creatinine and total calcium concentration were measured after one year of treatment and multiple linear regression was used to estimate effects on creatinine concentrations. Results After one year of treatment, blood creatinine was 0.013±0.006 mg/dL higher on average among participants randomized to calcium compared to placebo after adjustment for other determinants of creatinine (P?=?0.03). However, the effect of calcium treatment appeared to be larger among participants who consumed the most alcohol (2–6 drinks/day) or whose estimated glomerular filtration rate (eGFR) was less than 60 ml/min/1.73 m2 at baseline. The effect of calcium treatment on creatinine was only partially mediated by a concomitant increase in blood total calcium concentration and was independent of randomized vitamin D treatment. There did not appear to be further increases in creatinine after the first year of calcium treatment. Conclusions Among healthy adults participating in a randomized clinical trial, daily supplementation with 1200 mg of elemental calcium caused a small increase in blood creatinine. If confirmed, this finding may have implications for clinical and public health recommendations for calcium supplementation. Trial Registration ClinicalTrials.gov NCT00153816 PMID:25329821

Barry, Elizabeth L.; Mott, Leila A.; Melamed, Michal L.; Rees, Judith R.; Ivanova, Anastasia; Sandler, Robert S.; Ahnen, Dennis J.; Bresalier, Robert S.; Summers, Robert W.; Bostick, Roberd M.; Baron, John A.

2014-01-01

152

Enzymatic characterization of a prokaryotic urea carboxylase.  

PubMed

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

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

2004-05-01

153

Enzymatic Characterization of a Prokaryotic Urea Carboxylase  

PubMed Central

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

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

2004-01-01

154

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

PubMed Central

Excessive dietary fructose intake may have an important role in the current epidemics of fatty liver, obesity and diabetes as its intake parallels the development of these syndromes and because it can induce features of metabolic syndrome. The effects of fructose to induce fatty liver, hypertriglyceridemia and insulin resistance, however, vary dramatically among individuals. The first step in fructose metabolism is mediated by fructokinase (KHK), which phosphorylates fructose to fructose-1-phosphate; intracellular uric acid is also generated as a consequence of the transient ATP depletion that occurs during this reaction. Here we show in human hepatocytes that uric acid up-regulates KHK expression thus leading to the amplification of the lipogenic effects of fructose. Inhibition of uric acid production markedly blocked fructose-induced triglyceride accumulation in hepatocytes in vitro and in vivo. The mechanism whereby uric acid stimulates KHK expression involves the activation of the transcription factor ChREBP, which, in turn, results in the transcriptional activation of KHK by binding to a specific sequence within its promoter. Since subjects sensitive to fructose often develop phenotypes associated with hyperuricemia, uric acid may be an underlying factor in sensitizing hepatocytes to fructose metabolism during the development of fatty liver. PMID:23112875

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

2012-01-01

155

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

PubMed

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

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

2014-01-01

156

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 ...

157

Xenobiotic-urea conjugates; chemical or biological?  

PubMed

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

Mitchell, Stephen C

2014-12-01

158

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

PubMed

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. PMID:24800491

Horio, Masaru

2014-02-01

159

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

SciTech Connect

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

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

1986-05-29

160

Multisite evaluation of a new dipstick for albumin, protein, and creatinine.  

PubMed

The goal of our study was to perform a multisite evaluation of a new urine dipstick called Multistix PROtrade mark (Bayer, Elkhart, IN), which has reagent pads for the simultaneous assay of urinary albumin, protein, and creatinine. Patients' urine specimens were assayed at four sites with these dipsticks and with the familiar Bayer Multistix 10SG dipsticks for protein. The new dipstick pads for albumin are impregnated with bis (3',3"-diiodo-4',4"-dihydroxy-5',5"-dinitrophenyl)-3,4,5,6-tetrabromo-sulfonephthalein (DIDNTB) dye. These dipsticks also have a novel pad that estimates urinary creatinine using the peroxidase activity of the copper-creatinine complex. We determined the interlaboratory agreement of these dipsticks by comparing dipstick results to values obtained by quantitative analytical methods. We found that dividing the dipsticks' albumin or protein results by the creatinine concentration reduced the number of false-positive albumin or protein values observed in concentrated urines, and reduced the number of false negatives in dilute urines. The ratio of albumin to creatinine, or protein to creatinine gives a better measure of albumin or protein excretion. Compared to reading by eye, the dipstick results agreed better with the quantitative assays when they were read by a reflectometer (Bayer Clinitek). PMID:11574949

Wallace, J F; Pugia, M J; Lott, J A; Luke, K E; Shihabi, Z K; Sheehan, M; Bucksa, J M

2001-01-01

161

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

PubMed

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

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

2007-04-01

162

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

Microsoft Academic Search

Cellulose degradation of 20% urea treated and 20% urea–10kGy 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

Siriwattana Banchorndhevakul

2002-01-01

163

Copy number polymorphisms near SLC2A9 are associated with serum uric acid concentrations  

PubMed Central

Background Hyperuricemia is associated with multiple diseases, including gout, cardiovascular disease, and renal disease. Serum urate is highly heritable, yet association studies of single nucleotide polymorphisms (SNPs) and serum uric acid explain a small fraction of the heritability. Whether copy number polymorphisms (CNPs) contribute to uric acid levels is unknown. Results We assessed copy number on a genome-wide scale among 8,411 individuals of European ancestry (EA) who participated in the Atherosclerosis Risk in Communities (ARIC) study. CNPs upstream of the urate transporter SLC2A9 on chromosome 4p16.1 are associated with uric acid (?2df2=3545, p=3.19×10-23). Effect sizes, expressed as the percentage change in uric acid per deleted copy, are most pronounced among women (3.974.935.87 [ 2.55097.5 denoting percentiles], p=4.57×10-23) and independent of previously reported SNPs in SLC2A9 as assessed by SNP and CNP regression models and the phasing SNP and CNP haplotypes (?2df2=3190,p=7.23×10-08). Our finding is replicated in the Framingham Heart Study (FHS), where the effect size estimated from 4,089 women is comparable to ARIC in direction and magnitude (1.414.707.88, p=5.46×10-03). Conclusions This is the first study to characterize CNPs in ARIC and the first genome-wide analysis of CNPs and uric acid. Our findings suggests a novel, non-coding regulatory mechanism for SLC2A9-mediated modulation of serum uric acid, and detail a bioinformatic approach for assessing the contribution of CNPs to heritable traits in large population-based studies where technical sources of variation are substantial. PMID:25007794

2014-01-01

164

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

USGS Publications Warehouse

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

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

2010-01-01

165

Association between Vitamin D Insufficiency and Elevated Serum Uric Acid among Middle-Aged and Elderly Chinese Han Women  

PubMed Central

Background Association between vitamin D insufficiency and hyperuricemia has not been reported so far. We aimed to study the association of vitamin D insufficiency with elevated serum uric acid among middle-aged and elderly Chinese Han women. Methods We collected data from participants residing in Jinchang district of Suzhou from January to May, 2010. Serum uric acid, 25-hydroxy vitamin D and other traditional biomarkers including fasting plasma glucose and blood lipids were determined in 1726 women aged above 30 years. Association between vitamin D insufficiency and elevated uric acid was analyzed in premenopausal and postmenopausal women, respectively. Results Among postmenopausal women, 25-hydroxy vitamin D level of participants with elevated uric acid was lower than that of those with normal uric acid (median [interquartile range]: 35[28–57] vs 40[32–58], µg/L; P?=?0.006). Elevated uric acid was more prevalent in participants with vitamin D insufficiency compared to those without vitamin D insufficiency (16.50% vs 8.08%; P<0.001). Association between vitamin D insufficiency and elevated uric acid was not significant among premenopausal women. However, participants with vitamin D insufficiency were more likely to have elevated uric acid compared with those without vitamin D insufficiency among postmenopausal women (OR, 95% CI: 2.38, 1.47–3.87). Moreover, after excluding individuals with diabetes and/or hypertension, the association of vitamin D insufficiency with elevated uric acid was still significant (OR, 95% CI: 2.48, 1.17–5.44). Conclusions Vitamin D insufficiency was significantly associated with elevated uric acid among postmenopausal Chinese Han women. This study suggested that a clinical trial should be conducted to confirm the association of vitamin D insufficiency with hyperuricemia. PMID:23585876

Li, Chao; Chao, Xiangqin; Zhang, Qiu; Zhang, Yonghong

2013-01-01

166

Urea transporter knockout mice and their renal phenotypes.  

PubMed

Urea transporter gene knockout mice have been created for the study of the urine-concentrating mechanism. The major findings in studies of the renal phenotype of these mice are as follows: (1) Urea accumulation in the inner medullary interstitium is dependent on intrarenal urea recycling mediated by urea transporters; (2) urea transporters are essential for preventing urea-induced osmotic diuresis and thus for water conservation; (3) NaCl concentration in the inner medullary interstitium is not significantly affected by the absence of IMCD, descending limb of Henle and descending vasa recta urea transporters. Studies in urea transporter knockout mouse models have highlighted the essential role of urea for producing maximally concentrated urine. PMID:25298343

Fenton, Robert A; Yang, Baoxue

2014-01-01

167

Serum uric acid in relation to endogenous reproductive hormones during the menstrual cycle: findings from the BioCycle study  

PubMed Central

STUDY QUESTION Do uric acid levels across the menstrual cycle show associations with endogenous estradiol (E2) and reproductive hormone concentrations in regularly menstruating women? SUMMARY ANSWER Mean uric acid concentrations were highest during the follicular phase, and were inversely associated with E2 and progesterone, and positively associated with FSH. WHAT IS KNOWN ALREADY E2 may decrease serum levels of uric acid in post-menopausal women; however, the interplay between endogenous reproductive hormones and uric acid levels among regularly menstruating women has not been elucidated. STUDY DESIGN, SIZE, DURATION The BioCycle study was a prospective cohort study conducted at the University at Buffalo research centre from 2005 to 2007, which followed healthy women for one (n = 9) or 2 (n = 250) menstrual cycle(s). PARTICIPANTS/MATERIALS, SETTING, METHODS Participants were healthy women aged 18–44 years. Hormones and uric acid were measured in serum eight times each cycle for up to two cycles. Marginal structural models with inverse probability of exposure weights were used to evaluate the associations between endogenous hormones and uric acid concentrations. MAIN RESULTS AND THE ROLE OF CHANCE Uric acid levels were observed to vary across the menstrual cycle, with the lowest levels observed during the luteal phase. Every log-unit increase in E2 was associated with a decrease in uric acid of 1.1% (? = ?0.011; 95% confidence interval (CI): ?0.019, ?0.004; persistent-effects model), and for every log-unit increase in progesterone, uric acid decreased by ?0.8% (? = ?0.008; 95% CI: ?0.012, ?0.004; persistent-effects model). FSH was positively associated with uric acid concentrations, such that each log-unit increase was associated with a 1.6% increase in uric acid (? = 0.016; 95% CI: 0.005, 0.026; persistent-effects model). Progesterone and FSH were also associated with uric acid levels in acute-effects models. Of 509 cycles, 42 were anovulatory (8.3%). Higher uric acid levels were associated with increased odds of anovulation (odds ratio 2.39, 95% CI: 1.25, 4.56). LIMITATIONS, REASONS FOR CAUTION The change in uric acid levels among this cohort of healthy women was modest, and analysis was limited to two menstrual cycles. The women in this study were healthy and regularly menstruating, and as such there were few women with high uric acid levels and anovulatory cycles. WIDER IMPLICATIONS OF THE FINDINGS These findings demonstrate the importance of taking menstrual cycle phase into account when measuring uric acid in premenopausal women, and confirm the hypothesized beneficial lowering effects of endogenous E2 on uric acid levels. These findings suggest that there could be an underlying association affecting both sporadic anovulation and high uric acid levels among young, regularly menstruating women. Further studies are needed to confirm these findings and elucidate the connection between uric acid and reproductive and later cardiovascular health. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health (contract # HHSN275200403394C). No competing interests declared. PMID:23562957

Mumford, Sunni L.; Dasharathy, Sonya S.; Pollack, Anna Z.; Perkins, Neil J.; Mattison, Donald R.; Cole, Stephen R.; Wactawski-Wende, Jean; Schisterman, Enrique F.

2013-01-01

168

Graphene-carbon nanotube composite aerogel for selective detection of uric acid  

NASA Astrophysics Data System (ADS)

Graphene and single-walled carbon nanotube (SWNT) composite aerogel has been prepared by hydrothermal synthesis. The restacking of graphene is effectively reduced by SWNTs inserted in between graphene layers in order to make available more active sites and reactive surface area. Electrochemical experiments show that the graphene-SWNT composite electrode has superior catalytic performance in selective detection of uric acid (UA).

Zhang, Feifei; Tang, Jie; Wang, Zonghua; Qin, Lu-Chang

2013-12-01

169

Serum Uric Acid Levels Correlate with the Severity and the Mortality of Primary Pulmonary Hypertension  

Microsoft Academic Search

Serum uric acid (UA), the final product of purine degradation, has been proposed to be a marker for impaired oxidative metabolism and a possible predictor of mortality in patients with chronic heart failure. To elucidate whether serum UA correlates with the severity and the mortality of primary pul- monary hypertension (PPH), serum UA was assessed in 90 patients with PPH

NORITOSHI NAGAYA; MASAAKI UEMATSU; TORU SATOH; SHINGO KYOTANI; FUMIO SAKAMAKI; NORIFUMI NAKANISHI; MASAKAZU YAMAGISHI; TAKEYOSHI KUNIEDA; KUNIO MIYATAKE

1999-01-01

170

Uric Acid, Left Ventricular Mass Index, and Risk of Cardiovascular Disease in Essential Hypertension  

Microsoft Academic Search

Elevated serum uric acid (UA) is frequently encountered in individuals with hypertension, but whether the relationship between UA and cardiovascular events is circumstantial or causal remains to be answered. We examined the association between serum UA and left ventricular mass index (LVMI) and investigated prospectively whether the combination of UA and LVMI can predict the incidence of cardiovascular disease (CVD)

Yoshio Iwashima; Takeshi Horio; Kei Kamide; Hiromi Rakugi; Toshio Ogihara; Yuhei Kawano

2010-01-01

171

Relationship of uric acid concentrations and severe intraventricular hemorrhage\\/leukomalacia in the premature infant  

Microsoft Academic Search

The purine metabolite hypoxanthine accumulates with hypoxia ischemia and with reperfusion is converted to uric acid (UA). We hypothesized that elevated UA concentration is a marker of previous hypoxia ischemia and would identify infants at greatest risk for having subsequent intraventricular hemorrhage (IVH)\\/periventricular leukomalacia (PVL). We determined the relationship between UA concentrations in the first postnatal day and the development

Jeffrey M. Perlman; Richard Risser

1998-01-01

172

Uric acid and cognition in Parkinson’s disease: A follow-up study  

Microsoft Academic Search

Cognitive changes are common in Parkinson’s disease (PD). Low plasma uric acid (UA) level is associated with risk of PD and predicts faster progression of motor symptoms in established disease. Whether UA levels predict cognitive changes has not been studied. In a crossectional study, our group has previously shown an association of plasma and urine UA levels with cognition in

Tua Annanmaki; Marjatta Pohja; Tiina Parviainen; Paula Hakkinen; Kari Murros

2011-01-01

173

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

PubMed

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

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

2014-07-01

174

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

Microsoft Academic Search

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

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

2008-01-01

175

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

Microsoft Academic Search

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

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

1978-01-01

176

A Synthetic Uric Acid Analog Accelerates Cutaneous Wound Healing in Mice  

Microsoft Academic Search

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

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

2010-01-01

177

Biological microdevice with fluidic acoustic streaming for measuring uric acid in human saliva  

Microsoft Academic Search

The healthcare system requires new devices for a rapid monitoring of a patient in order to improve the diagnosis and treatment of various diseases. Accordingly, new biomedical devices are being developed. In this paper, a fully-integrated biological microdevice for uric acid analysis in human saliva is presented. It is based on optical spectrophotometric measurements and incorporates a mixture system based

V. F. Cardoso; S. O. Catarino; P. Martins; L. Rebouta; S. Lanceros-Mendez; G. Minas

2009-01-01

178

Accumulation of uric acid in plasma after repeated bouts of exercise in the horse  

Microsoft Academic Search

Plasma concentration of uric acid, total peroxyl radical-trapping antioxidative parameter (TRAP), blood lactate concentration and plasma activity of xanthine oxidase (XO) were measured in six Standardbreed trotters after six bouts of exercise with increasing intensity on two separate days three days apart. Blood samples were taken immediately, 5, 10, 15, 30 and 60 min after each heat and 2, 4,

Leena A. Räsänen; Pauliina A. S. Wiitanen; Esa-Matti Lilius; Seppo Hyyppä; A. Reeta Pösö

1996-01-01

179

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

ERIC Educational Resources Information Center

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

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

2009-01-01

180

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

PubMed

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

Recavarren, M I; Milano, G D

2014-12-01

181

[Calcium antagonists: current and future applications based on new evidence. The mechanisms on lowering serum uric acid level by calcium channel blockers].  

PubMed

In hypertensive subjects, their serum uric acid levels tend to be higher because of decreasing urinary secretion or overproduction of uric acid. Among calcium channel blockers (CCBs) , long acting nifedipine and cilnidipine reveal serum uric acid lowering action. They decrease the production of uric acid precursor in skeletal muscles under anaerobic condition induced by hypertension or insulin resistance. Hyperuricemia is considered to be a risk factor of not only gout but also renal and cardiovascular diseases, thus, it is important to use CCBs without adverse effect on uric acid metabolisms. PMID:20048433

Mizuta, Einosuke; Hamada, Toshihiro; Igawa, Osamu; Shigemasa, Chiaki; Hisatome, Ichiro

2010-01-01

182

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

PubMed

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

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

2014-10-01

183

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

USGS Publications Warehouse

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

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

1994-01-01

184

Association between serum uric acid and the metabolic syndrome among a middle- and old-age Chinese population.  

PubMed

Our aim was to study whether there is causal association between serum uric acid and metabolic syndrome (MetS). A cross-sectional study was performed, including a total of 27,009 subjects (23,345 subjects having uric acid data) from the Dongfeng-Tongji Cohort study. The MetS was defined by the International Diabetes Foundation criteria of 2005. Association analysis was performed by logistic regression. A genetic risk score was calculated by adding the uric acid increasing alleles in two SNPs (rs11722228 in SLC2A9 and rs2231142 in ABCG2) which were identified from our genome-wide association study on uric acid levels. The causal association was examined by mendelian randomization analysis. Among a middle- and old-age Chinese population, serum uric acid concentrations were strongly associated with the risk of MetS and its several components (P < 0.0001). The effects were stronger in women than in men. Despite the lack of statistical significance, both SNPs exhibited a trend with increased MetS risk (rs11722228, OR = 1.06, 95 % CI 0.99-1.14; rs2231142, OR = 1.02, 95 % CI 0.95-1.10), consistent with their increasing uric acid effects. Each additional uric acid increasing allele in the genetic risk score was associated with 3 % increased MetS risk (OR = 1.03, 95 % CI 0.98-1.09; P = 0.23). Further adjustment for serum uric acid attenuated the trend of individual SNP and genetic risk score with increased MetS risk (all OR < 1.0). These findings suggested that serum uric acid was associated with MetS risk in a middle- and old-age Chinese population. Whether this association was causal remained to be investigated in the future studies. PMID:23864233

Dai, Xiayun; Yuan, Jing; Yao, Ping; Yang, Binyao; Gui, Lixuan; Zhang, Xiaomin; Guo, Huan; Wang, Youjie; Chen, Weihong; Wei, Sheng; Miao, Xiaoping; Li, Xiulou; Min, Xinwen; Yang, Handong; Fang, Weimin; Liang, Yuan; Hu, Frank B; Wu, Tangchun; He, Meian

2013-08-01

185

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

PubMed

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

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

2014-05-15

186

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

PubMed

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

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

2014-10-15

187

Urea: a comprehensive review of the clinical literature  

E-print Network

effect of salicylic acid and urea in human skin. Skinsalicylic acid alone CT Single 4-hour application on back skinsalicylic acid ointment, and paraffin-based moisturizers [17]. The beneficial effects of urea on ichthyotic skin

Pan, Michael; Heinecke, Gillian; Bernardo, Sebastian; Tsui, Cindy; Levitt, Jacob

2013-01-01

188

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

PubMed Central

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

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

2011-01-01

189

Aldehyde-containing urea-absorbing polysaccharides  

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

190

Quantitative determination of urea concentrations in cell culture medium  

PubMed Central

Urea is the major nitrogenous end product of protein metabolism in mammals. Here, we describe a quantitative, sensitive method for urea determination using a modified Jung reagent. This assay is specific for urea and is unaffected by ammonia, a common interferent in tissue and cell cultures. We demonstrate that this convenient colorimetric microplate-based, room temperature assay can be applied to determine urea synthesis in cell culture. PMID:19448747

Zawada, Robert J.X.; Kwan, Peggy; Olszewski, Kellen L.; Llinas, Manuel; Huang, Shu-Gui

2009-01-01

191

Phenol–urea–formaldehyde (PUF) co-condensed wood adhesives  

Microsoft Academic Search

The reaction of urea with methylolphenol under acidic conditions was investigated. The alternating copolymer of urea and phenol could be synthesized by the reaction of urea and 2,4,6-trimethylolphenol. The reactions of urea with polymethylolphenol mixtures also were investigated by changing the reaction conditions, such as the molar ratio and acidity. The co-condensates were analysed by carbon-13 nuclear magnetic resonance spectroscopy

Bunichiro Tomita; Chung-Yun Hse

1998-01-01

192

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

PubMed

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

Ghosh, Tanushree; Sarkar, Priyabrata

2014-12-01

193

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

PubMed Central

Background: Serum creatinine as a classic marker of renal function has several limitations in the detection of renal dysfunction. Objectives: This study assessed the validity of serum cystatin C as a marker of renal function in critically ill patients with normal serum creatinine. Patients and Methods: Eighty adult patients referred to intensive care units with serum creatinine levels < 1.5 mg/dL and without hemodynamic instability were chosen and their serum creatinine and cystatin C levels were measured. A 24-hour urine sample was collected to calculate creatinine clearance (Ccr). Renal dysfunction was defined as Ccr < 80 mL/min/1.73 m2. Results: There were significant correlations between measured Ccr and 1/serum creatinine (R = 0.51, P < 0.001) and 1/serum cystatin C (R = 0.25, P = 0.028). The difference between false negative rates of serum creatinine (93.33%) and cystatin C (80%) in the detection of renal dysfunction was significant (P = 0.032). Receiver operating characteristic curve analysis illustrated that area under the curve of serum creatinine and cystatin C for detecting renal dysfunction were 0.711 and 0.607, respectively; however, this difference was not significant (P = 0.222). Conclusions: Our data demonstrated that serum cystatin C is not superior to serum creatinine in the early detection of renal dysfunction in critically ill patients. PMID:24783172

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

2014-01-01

194

76 FR 15339 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013

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

2011-03-21

195

76 FR 77015 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013

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

2011-12-09

196

75 FR 74746 - Solid Urea From Russia and Ukraine  

Federal Register 2010, 2011, 2012, 2013

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

2010-12-01

197

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. ...

198

Synergetic Effects of Nanoporous Support and Urea on Enzyme Activity  

SciTech Connect

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

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

2007-02-01

199

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

PubMed Central

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

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

1972-01-01

200

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

PubMed Central

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

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

1972-01-01

201

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

PubMed Central

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

Agarwal, Banwari; Davenport, Andrew

2014-01-01

202

Genderwise Comparison of Serum Creatinine and Blood Sugar Levels in Type2 Diabetic Patients  

Microsoft Academic Search

Results : Beyond the age of 40 years, mean blood sugar levels of female patients were significantly higher on comparing statistically with that of male patients; whereas the serum creatinine levels in male patients were significantly higher than females, indicating the effect of gender on progression of disease. Conclusion : This study will help clinicians to draw different baselines for

Tejal J Wagle

2010-01-01

203

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

EPA Science Inventory

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

204

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

PubMed

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

Agarwal, Banwari; Davenport, Andrew

2014-10-27

205

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

E-print Network

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

Hammock, Bruce D.

206

Uric acid: a starring role in the intricate scenario of metabolic syndrome with cardio-renal damage?  

Microsoft Academic Search

Elevated uric acid levels are a common finding in patients with metabolic syndrome and in those with cardiovascular and renal\\u000a disease, but the meaning of this elevation is still unclear. In patients with chronic kidney diseases, it could merely reflect\\u000a the reduction in glomerular filtration rate: but uric acid levels are known to be elevated in people, also in younger

Davide Stellato; Luigi Francesco Morrone; Chiara Di Giorgio; Loreto Gesualdo

207

HEMATOLOGY AND SERUM CHEMISTRY OF COTTONTAIL RABBITS OF SOUTHERN ILLINOIS  

Microsoft Academic Search

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

Dwayne A. W. Lepitzki; Alan Woolf

208

Biochemical Reference Ranges for Commercially Reared Channel Catfish  

Microsoft Academic Search

Reference ranges for serum osmolality and 22 serum constituents were determined for channel catfish (Ictalurus punctatus) reared under commercial conditions in Mississippi ponds for 8 months. The constituents analyzed were sodium, potassium, chloride, calcium, magnesium, inorganic phosphate, urea nitrogen, uric acid, creatinine, glucose, cholesterol, triglycerides, total protein, albumin, total bilirubin, lactate dehydrogenase, ?-glutamyltransferase, aspartate aminotransferase, alanine aminotransferase, creatine transferase, alkaline

J. Bentinck-Smith; M. H. Beleau; P. Waterstrat; C. S. Tucker; F. Stiles; P. R. Bowser; L. A. Brown

1987-01-01

209

The Protein and Non-Protein Nitrogen Fractions in Milk. I. Methods of Analysis1  

Microsoft Academic Search

While the major part of the nitrogen in milk is accounted by casein, albumin, globulin and proteoses-peptones, milk also contains nitrogen in the form of am- monia, urea, creatinine, creatine, uric acid and amino acids, and mere traces in the form of vitamins, enzymes, phospholipids and cerebrosides. The non-pro- tein nitrogen components of milk have not been studied extensively. They

K. M. Shahani; H. H. Sommer

1951-01-01

210

Serum uric acid concentrations in a Xhosa community in the Transkei of Southern Africa.  

PubMed Central

Serum uric acid (SUA) concentrations were measured in specimens obtained from 479 respondents aged 15 and over during an epidemiological survey of bone and joint conditions in a tribal Xhosa community living in the Transkei, Southern Africa. Population SUA levels in the Xhosa were significantly lower than those previously observed in South Africa Negro groups in rural and urban environments. This finding agrees with the observations that population SUA concentrations tend to rise with increasing complexity of life style. PMID:1275585

Beighton, P; Daynes, G; Soskolne, C L

1976-01-01

211

The cincinnati lipid research clinic family study: Familial determinants of plasma uric acid  

Microsoft Academic Search

Commingling analysis of plasma uric acid levels in a random sample of 160 nuclear families supports the hypothesis that there is a mixture of three distributions. Assuming one, two, and three components in the underlying distribution, we obtained the corresponding p-values (for power transformation) as 0.059, 1.040, and 1.643, respectively. Path analysis with p=0.059 gives genetic (h2) and cultural (c2)

D. C. Rao; P. M. Laskarzewski; J. A. Morrison; P. Khoury; K. Kelly; C. J. Glueck

1982-01-01

212

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

Microsoft Academic Search

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

S. Abraham John

2005-01-01

213

Dual-energy computed tomography for the differentiation of uric acid stones: ex vivo performance evaluation  

Microsoft Academic Search

We assessed the potential of dual-energy computed tomography (CT) for the differentiation between uric acid (UA)-containing\\u000a and non-UA-containing urinary stones. Forty urinary stones of 16 different compositions in two sizes (< and ? 5 mm) were examined\\u000a in an ex vivo model. Thirty stones consisted of pure calcium oxalate (whewellite or wheddellite), calcium phosphate (apatite,\\u000a brushite, or vaterite), ammonium magnesium phosphate (struvite), UA, ammonium

Paul Stolzmann; Hans Scheffel; Katharina Rentsch; Thomas Schertler; Thomas Frauenfelder; Sebastian Leschka; Tullio Sulser; Borut Marincek; Hatem Alkadhi

2008-01-01

214

Relations of Serum Uric Acid to Longitudinal Blood Pressure Tracking and Hypertension Incidence  

Microsoft Academic Search

Serum uric acid (UA) has been implicated in the pathogenesis of hypertension. We investigated the relationship of serum UA to hypertension incidence and blood pressure (BP) progression in 3329 Framingham Study participants (mean age 48.7 years; 55.6% women) free of hypertension, myocardial infarction, heart failure, renal failure, or gout. At follow-up 4 years from baseline, 458 persons (13.8%) had developed

Johan Sundstrom; Lisa Sullivan; Ralph B. D'Agostino; Daniel Levy; William B. Kannel; Ramachandran S. Vasan

2010-01-01

215

Accumulation of allantoin and uric acid in plasma of exercising trotters.  

PubMed

Plasma concentrations of hypoxanthine, uric acid, and allantoin, which are breakdown products of adenine nucleotides, were measured in Standardbred and Finnhorse trotters during and after an exercise test on a high-speed treadmill, after an incremental exercise test performed on a racetrack, and after a racing competition. Fiber-type composition of the middle gluteal muscle and the muscle concentrations of adenine nucleotides and inosine monophosphate were measured after the racetrack test. Changes in the concentration of hypoxanthine were not observed in any of the tests. Peak concentration of uric acid was measured between 5 and 30 minutes after exercise, and it was three- to tenfold higher than the value at rest. The variability can be explained by intensity of the exercise test and variation among horses. The concentration of allantoin after exercise was 2 to 3 times as high as that at rest, depending on the intensity of the exercise, although the absolute increase was about 10 times as high as the increase in the concentration of uric acid. Peak values of allantoin for the treadmill and the racetrack tests were obtained 4 to 6 minutes after exercise and < 30 minutes after the races. Peak concentration of allantoin correlated positively with the percentage of type-II (IIA+IIB) fibers in the middle gluteal muscle. Significant correlations were not observed between plasma concentration of uric acid or allantoin and muscle concentrations of adenosine triphosphate (ATP) or inosine monophosphate. It can be concluded that in horses, breakdown of ATP during and after exercise continues until allantoin is produced.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8291774

Räsänen, L A; Myllymäki, T; Hyyppä, S; Maisi, P; Pösö, A R

1993-11-01

216

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

PubMed

An optical polymeric biochip system based on the complementary metal oxide semiconductor (CMOS) photo array sensor and polymeric enzyme biochip for rapidly quantitating uric acid in a one-step procedure was developed. The CMOS sensor was designed with N(+)/P-well structure and manufactured using a standard 0.5 microm CMOS process. The polymeric enzyme biochip was immobilized with uricase-peroxidase and used to fill the reacting medium with the sample. This study encompasses the cloning of the Bacillus subtilis uricase gene and expression in Escherichia coli, as well as the purification of uricase and measurement of its activity. The cloned uricase gene included an open reading frame of 1491 nucleotides that encodes a protein of approximately 55 kDa. The expression of the putative MBP-fusion protein involved approximately 98 kDa of the protein. The CMOS sensor response was stronger at a higher temperature range of 20-40 degrees C, with optimal pH at 8.5. The calibration curve of purified uric acid was linear in the concentration range from 2.5 to 12.5 mg/dL. The results obtained for serum uric acid correlated quite closely with those obtained using the Beckman Synchron method. PMID:15142596

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

2004-07-15

217

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

PubMed Central

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

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

2008-01-01

218

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

PubMed Central

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

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

2014-01-01

219

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

Microsoft Academic Search

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

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

2002-01-01

220

Neurological implications of urea cycle disorders  

PubMed Central

Summary 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 1H 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. PMID:18038189

Summar, M.; Leonard, J. V.

2013-01-01

221

A longitudinal study of urea cycle disorders.  

PubMed

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

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

2014-01-01

222

A comparison of CKD-EPI estimated glomerular filtration rate and measured creatinine clearance in recently admitted critically ill patients with normal plasma creatinine concentrations  

PubMed Central

Background The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimated glomerular filtration rate (eGFR) has been widely integrated into clinical practice. Although useful in screening for CKD, its’ application in critically ill patients with normal plasma creatinine concentrations remains uncertain. The aim of this study was to assess the performance of CKD-EPI eGFR in comparison to creatinine clearance (CLCR) in this setting. Methods This prospective observational study was performed in a tertiary level, university affiliated intensive care unit (ICU). Study participants had to have an expected ICU length of stay?>?24 hours, a plasma creatinine concentration?

2013-01-01

223

The rate of production of uric acid by hepatocytes is a sensitive index of compromised cell ATP homeostasis.  

PubMed

Plasma levels of uric acid, the final product of purine degradation in humans, are elevated in metabolic syndrome and are strongly associated with insulin resistance and nonalcoholic fatty liver disease (NAFLD). Hepatic and blood levels of purine metabolites (inosine, hypoxanthine, and xanthine) are also altered in pathophysiological states. We optimized a rat hepatocyte model to test the hypothesis that the production of uric acid by hepatocytes is a potential marker of compromised homeostasis of hepatocellular inorganic phosphate (Pi) and/or ATP. The basal rate of uric acid production from endogenous substrates in rat hepatocytes was comparable to that in human liver and was <10% of the maximum rate with saturating concentrations of purine substrates. It was marginally (~20%) decreased by insulin and increased by glucagon but was stimulated more than twofold by substrates (fructose and glycerol) that lower both cell ATP and Pi, and by inhibitors of mitochondrial respiration (complexes I, III, and V) that lower ATP but raise cell Pi. Clearance of inosine and its degradation to uric acid were also inhibited by cell Pi depletion. Analysis of gene expression in NAFLD biopsies showed an association between mRNA expression of GCKR, the glucokinase regulatory protein that is functionally linked to uric acid production, and mRNA expression of the phosphate transporters encoded by SLC17A1/3. Uric acid production by hepatocytes is a very sensitive index of ATP depletion irrespective of whether cell Pi is lowered or raised. This suggests that raised plasma uric acid may be a marker of compromised hepatic ATP homeostasis. PMID:24045866

Petrie, John L; Patman, Gillian L; Sinha, Ishita; Alexander, Thomas D; Reeves, Helen L; Agius, Loranne

2013-11-15

224

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

Microsoft Academic Search

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

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

2011-01-01

225

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

PubMed Central

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

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

2013-01-01

226

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

PubMed Central

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

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

2014-01-01

227

Formation of mutagens during the frying of Hawaiian fish: correlation with creatine and creatinine content.  

PubMed

Compounds mutagenic toward Salmonella typhimurium strain TA98 in the presence of rat-liver homogenates (S9) were formed when fish flesh was fried at 199 degrees C. Three species of Hawaiian fish commonly consumed in Hawaii (skipjack tuna, Katsuwonus pelamis; yellowfin tuna, Neothunnus macropterus; and milkfish, Chanos chanos) were cooked in an electric skillet, along with samples of sole (Microstomus pacificus). Organic extracts of the fish were tested in the Ames Salmonella mutagenic assay using tester strain TA98 and S9. Basic organic extracts of fried, but not raw, samples exhibited significant mutagenicity. The levels of mutagenicity were also higher among the red flesh Hawaiian fish ('ahi, aku and awa) than with the white flesh sole. Creatine and creatinine contents were highest in the Hawaiian fish and lower in the sole. Creatine levels in the fish were 50-100 times greater than the creatinine content and varied from a high of 645 mg/100 g wet weight of fish for yellowfin tuna to a low value of 251 mg/100 g for sole. Mutagen levels are only approximately related to creatine/creatinine levels suggesting that other components contained in these fish may be as important as the guanidines in determining the levels of mutagen in the cooked fish. PMID:2270090

Marsh, N L; Iwaoka, W T; Mower, H F

1990-11-01

228

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

PubMed

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

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

2014-10-01

229

Reversible inhibition of urea exchange in rat hepatocytes.  

PubMed Central

Urea exchange is enhanced in renal collecting duct cells and erythrocytes by transporters which can be inhibited by phloretin and urea analogs such as thiourea. In this study, evidence for a comparable transporter was found in rat livers perfused with solutions which contained no red cells and in suspensions of hepatocytes. Bolus injections containing 125I-albumin (intravascular indicator), 99mTc-DTPA (extracellular indicator), 3HOH (water indicator), and [14C]urea were administered into the portal vein and fluid was collected from the hepatic vein. Under control conditions, [14C]urea and 3HOH emerged from the hepatic vein at nearly the same rate. However when the perfusate contained 2.5 mM phloretin (equivalent to 0.058 mM phloretin not bound to albumin), the amount of [14C]urea which had been recovered in the hepatic venous outflow by the time of peak 125I-albumin concentrations exceeded 3HOH recovery by a factor of 2.31 +/- 0.23 (n = 7). When the perfusate contained 200 mM thiourea, the comparable recovery of [14C]urea from the hepatic veins exceeded that of 3HOH by a factor of 3.48 +/- 0.44 (n = 7). These effects were at least partially reversible and suggested inhibition of urea transporters in hepatocytes. This conclusion was supported by studies of unloading of [14C]urea from hepatocytes which were exposed to unlabeled solutions: in the presence of phloretin, the amount of [14C]urea remaining within hepatocytes at 4 s was approximately twice that remaining in hepatocytes which had not been exposed to phloretin. Rapid transport of urea out of hepatocytes may increase urea synthesis and minimize cellular swelling due to urea accumulation. PMID:8514890

Effros, R M; Jacobs, E; Hacker, A; Ozker, K; Murphy, C

1993-01-01

230

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

PubMed Central

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

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

2013-01-01

231

Urea hydrolysis and calcium carbonate reaction fronts  

NASA Astrophysics Data System (ADS)

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, characterized by the pH profile and hydrolysis reaction species, was extended downstream of the enzyme zone. Downstream extension of the reaction profile was due partially to the partial mobility of the enzyme in the column. The experiments are helping to illustrate the complexity of transient reaction fronts as well as the needs and challenges for advanced modeling approaches. A modeling platform developed at the Idaho National Laboratory, which is capable of simulating tightly coupled physical-chemical processes (the Reactive Transport simulator), is being applied to pre-experimental simulations and post-experimental interpretation of results.

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

2010-12-01

232

1-Methyl-3-phenyl-thio-urea  

PubMed Central

The title compound, C8H10N2S, was prepared by reaction of methyl­amine solution, KOH and phenyl-iso­thio­cyanate in ethanol. It adopts a syn-Me and anti-Ph conformation relative to the C=S double bond. The dihedral angle between the N—C(=S)—N thio­urea and phenyl planes is 67.83?(6)°. In the crystal, the mol­ecules centrosymmetrical dimers by pairs of N(Ph)—H?S hydrogen bonds. The dimers are linked by N(Me)—H?S hydrogen bonds into layers parallel to (100). PMID:24860341

Su, Hou-xiang

2014-01-01

233

Functional Nanomaterials from Bis-urea Macrocycles  

NASA Astrophysics Data System (ADS)

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

Dawn, Sandipan

234

Difatty acyl urea from corn oil: synthesis and characterization.  

PubMed

In this study, difatty acyl urea has been successfully synthesized from corn oil using sodium ethoxide as a catalyst. Ethyl fatty ester and glycerol were produced as by-products. In this reaction, corn oil was refluxed with urea in ethanol. The highest conversion percentage (78%) was obtained when the process was carried out for 8 hours using urea to corn oil ratio of 5.6: 1.0 at 78 degrees C. Both difatty acyl urea and ethyl fatty ester have been characterized using elemental analysis, Fourier transform infrared (FTIR) spectroscopy and (1)H nuclear magnetic resonance (NMR) technique. PMID:20124758

Al-Mulla, Emad A Jaffar; Yunus, Wan Md Zin Wan; Ibrahim, Nor Azowa Bt; Rahman, Mohd Zaki A

2010-01-01

235

Osmolyte counteracts urea-induced denaturation of alpha-chymotrypsin.  

PubMed

The stability of proteins is reduced by urea, which is methylamine and nonprotecting osmolyte; eventually urea destabilizes the activity and function and alters the structure of proteins, whereas the stability of proteins is raised by the osmolytes, which are not interfering with the functional activity of proteins. The deleterious effect of urea on proteins has been counteracted by methylamines (osmolytes), such as trimethylamine N-oxide (TMAO), betaine, and sarcosine. To distinctly enunciate the comparison of the counteracting effects between these methylamines on urea-induced denaturation of alpha-chymotrypsin (CT), we measured the hydrodynamic diameter (d(H)) and the thermodynamic properties (T(m), DeltaH, DeltaG(U), and DeltaC(p)) with dynamic light scattering (DLS) and differential scanning calorimeter (DSC), respectively. The present investigation compares the compatibility and counteracting hypothesis by determining the effects of methylamines and urea, as individual components and in combination at a concentration ratio of 1:2 (methylamine:urea) as well as various urea concentrations (0.5-5 M) in the presence of 1 M methylamine. The experimental results revealed that the naturally occurring osmolytes TMAO, betaine, and sarcosine strongly counteracted the urea actions on alpha-chymotrypsin. The results also indicated that TMAO counteracting the urea effects on CT was much stronger than betaine or sarcosine. PMID:19354310

Venkatesu, Pannur; Lee, Ming-Jer; Lin, Ho-Mu

2009-04-16

236

21 CFR 862.1770 - Urea nitrogen test system.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

237

21 CFR 862.1770 - Urea nitrogen test system.  

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

2014-04-01

238

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

E-print Network

of urea-water solution decomposition, for gas temperatures between 550 and 650 K, the highest concentrations were for NH3 and HNCO. On the other hand, the concentrations of CO2 were highest for gas temperatures of about 500 - 550 K. For temperatures above...

Park, Yong Hun

2004-09-30

239

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

E-print Network

binding to urea dimers in the gas-phase was studied at the coupled cluster level with single and double.e., the nonplanar Cs-symmetry ``syn'' conformation and the planar C2V structure also form stable anions of dipole Finally, we found that the syn conformation of isourea sup- ports a dipole-bound anionic state

Simons, Jack

240

Bilateral obstructing ureteral uric acid stones in an infant with hereditary renal hypouricemia.  

PubMed

We report on a 15-month-old boy with renal hypouricemia who presented with acute renal failure, anuria and sepsis due to bilateral obstructing ureteral uric acid stones. He was treated successfully with extracorporeal shock wave lithotripsy. Metabolic survey of 10 relatives revealed a rare hereditary disorder in 4 siblings: isolated renal hypouricemia and hyperuricosuria. To our knowledge this is the youngest reported case of hereditary renal hypouricemia and 1 of the youngest patients to be treated with extracorporeal shock wave lithotripsy. PMID:8501797

Gofrit, O; Verstandig, A G; Pode, D

1993-06-01

241

Creatinine levels among Mexican Americans, Puerto Ricans, and Cuban Americans in the Hispanic Health and Nutrition Examination Survey  

Microsoft Academic Search

Creatinine levels among Mexican Americans, Puerto Ricans, and Cuban Americans in the Hispanic Health and Nutrition Examination Survey.BackgroundAlthough Latinos constitute the largest and fastest growing minority group in the United States, little is known about the prevalence of renal disease among different Latino subgroups.MethodsWe used data from the Hispanic Health and Nutrition Examination Survey (HHANES) to compare serum creatinine measurements

Rudolph A. Rodriguez; German T. Hernandez; Ann M. O'Hare; David V. Glidden

2004-01-01

242

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

Microsoft Academic Search

A new zinc oxide nanoparticles\\/chitosan\\/carboxylated multiwall carbonnanotube\\/polyaniline (ZnO-NPs\\/CHIT\\/c-MWCNT\\/PANI) composite film has been synthesized on platinum (Pt) electrode using electrochemical techniques. Three enzymes, creatinine amidohydrolase (CA), creatine amidinohydrolase (CI) and sarcosine oxidase (SO) were immobilized on ZnO-NPs\\/CHIT\\/c-MWCNT\\/PANI\\/Pt electrode to construct the creatinine biosensor. The enzyme electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance

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

2011-01-01

243

Inducing electrocatalytic functionality in ZnO thin film by N doping to realize a third generation uric acid biosensor.  

PubMed

A third generation uric acid biosensor has been developed by exploiting the electrocatalytic functionality of nitrogen (N) doped zinc oxide (ZnO:N) thin film matrix deposited using pulsed laser deposition technique. The electrochemistry of ZnO:N thin film based electrode is investigated by using electrochemical impedance spectroscopy and cyclic voltammetry. The obtained results demonstrate that nitrogen doping in ZnO matrix offers a striking electrocatalytic activity to the immobilized uricase towards the oxidation of analyte (uric acid) and promotes the direct transfer of electrons from active sites of enzyme onto the electrode without any mediator. In contrast to pure ZnO, ZnO:N (8% N) thin film based uric acid biosensor gives a high sensitivity of about 1.38 mA/mM in the absence of mediator. Moreover, ZnO:N derived bio-electrode exhibits excellent selectivity and outstanding analytical stability and reproducibility, which enables a reliable and sensitive determination of uric acid in the serum. The ZnO:N thin film based biosensor exhibits a linear sensing response in the range from 0 to 1.0mM of uric acid concentration and the apparent Michaelis-Menten kinetic parameter (Km) is estimated to be about 0.13 mM which indicates the high affinity of the prepared bio-electrode towards uric acid. The obtained results are encouraging and indicate that the ZnO:N thin film matrix offers a new and promising platform for the development of novel third generation biosensors without using any mediator. PMID:24362079

Jindal, Kajal; Tomar, Monika; Gupta, Vinay

2014-05-15

244

Importance of urinary NGAL, serum creatinine standardization and estimated glomerular filtration rate in resistant hypertension.  

PubMed

In patients with resistant hypertension (RH) we investigated the importance of urinary neutrophil gelatinase-associated lipocalin (uNGAL- a chemiluminescent microparticle immunoassay (CMIA) method became using (Abbott Diagnostics) for the measurement of NGAL in urine samples) and incidence of chronic kidney disease using the Modification of Diet in Renal Disease Study (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in estimating glomerular filtration rate (eGFR) based on standardised serum creatinine method traceable to isotope dilution mass spectrometry (IDMS) method. It would have been difficult to predict that levels of these biomarker would perform better organ damage than traditional measurements of kidney function such as standardised serum creatinine, MDRD, or CKD-EPI equations in special population such as RH. Serum creatinine concentrations were measured in 50 patients (24M:26F from RH Registar in Clinical Hospital Merkur) by the kinetic Jaffe method. There were no significant differences between the GFR values derived by MDRD and CKD-EPI equations in the group of patients with RH. 62% of patients have eGFR > 60 mL/minl/1.73 m2, while a 38% of patients have eGFR < 60 mL/min/1.73 m2. The measurement of NGAL in urine samples of 40 patients with RH showed no difference and seems to be of no use in further determination of renal impairement. Higher value of uNGAL in some resistant hypertension patients could have link in the repair stage after AKI and would reveal pathways that could link AKI and CKD. PMID:24308223

Prkacin, Ingrid; Ozvald, Ivan; Cavri?, Gordana; Balenovi?, Diana; Bulum, Tomislav; Flegar-Mestri?, Zlata

2013-09-01

245

Which Creatinine and Cystatin C Equations Can Be Reliably Used in Children?  

PubMed Central

Summary Background and objectives Estimation of GFR in children is challenging; reference methods are cumbersome, and formulas have limitations. The aims of this study were to evaluate (1) the new creatinine-based formula recently proposed by Schwartz using a kinetic colorimetric compensated Jaffe technique; (2) some cystatin C-derived formulas (Hoek, Le Bricon, Larsson, Rule, Filler, and Zappitelli) using a nephelemetric technique; and (3) combined formulas using both cystatin and creatinine (Zappitelli and Bouvet). Design, setting, participants, & measurements These formulas were evaluated in a cross-sectional cohort of 252 children with moderate CKD or normal GFR, in comparison with the reference standard (inulin clearance, iGFR). Mean age, body weight, height, creatinine, and cystatin C were 10.7 ± 4.0 years, 35 ± 15 kg, 137 ± 20 cm, 55 ± 30 ?mol/L, and 0.91 ± 0.35 mg/L, respectively. Results Mean ± SD iGFR was 101 ± 32 ml/min per 1.73 m2. When evaluating agreement between these formulas and iGFR (e.g. correlation, Bland Altman plots, bias, and accuracies), there was a good correlation between iGFR and all Le Bricon, Larsson, Rule, and Zappitelli (both) and locally adapted Schwartz and 2009 Schwartz formulas; by contrast, Filler and original 1976 Schwartz formulas overestimated iGFR, whereas Hoek and Bouvet formulas underestimated iGFR. Conclusion Different cystatin C-derived formulas (at least Larsson and Le Bricon) for estimating GFR as well as the Zappitelli combined formula are accurate in addition to the new Schwartz bedside formula in a general pediatric population. PMID:21115623

Cochat, Pierre; Rognant, Nicolas; Ranchin, Bruno; Hadj-Aissa, Aoumeur; Dubourg, Laurence

2011-01-01

246

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

NASA Astrophysics Data System (ADS)

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

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

2003-01-01

247

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

PubMed

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?m(2)) 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?m(2) higher (P < 0.0001) than eGFRcys. The prevalence of eGFR <60?mL/min/1.73?m(2) 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?m(2). PMID:25215234

Lujambio, Inés; Sottolano, Mariana; Luzardo, Leonella; Robaina, Sebastián; Krul, Nadia; Thijs, Lutgarde; Carusso, Florencia; da Rosa, Alicia; Ríos, Ana Carina; Olascoaga, Alicia; Garau, Mariela; Gadola, Liliana; Noboa, Oscar; Staessen, Jan A; Boggia, José

2014-01-01

248

Evidence that the Adverse Effect of Urea Fertilizer on Seed Germination in Soil is Due to Ammonia Formed through Hydrolysis of Urea by Soil Urease  

Microsoft Academic Search

Studies using seeds of wheat (Triticum aestivum L.), rye (Secale cereale L.), barley (Hordeum vulgare L.), and corn (Zea mays L.) indicated that the adverse effect of urea fertilizer on seed germination in soil is due to ammonia formed through hydrolysis of urea by soil urease and is not due to urea itself, to urea fertilizer impurities such as biuret,

John M. Bremner; Michael J. Krogmeier

1989-01-01

249

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

PubMed

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

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

2014-04-20

250

Protein expression of urate transporters in renal tissue of patients with uric acid nephrolithiasis.  

PubMed

URAT1 and GLUT9 are two primary urate transporters involved in the renal urate handling. Renal urate underexcretion was reported in uric acid stone formers (UASF) in previous clinical studies. The aim of this study was to investigate the clinical features and possible impact of protein expression of URAT1 and GLUT9 in renal tissues of patients with uric acid (UA) nephrolithiasis. 23 UASF, 27 patients with calcium oxalate (CaOx) stones, and 22 normal controls were enrolled in this study. Clinical data revealed that older age of onset, high plasma UA concentration, low urinary PH, and relative renal urate underexcretion were associated with UASF. By immunohistochemical or western blotting analysis, a significant increase in the relative expression quantity of URAT1 in renal tissue of UASF was found compared to patients with CaOx nephrolithiasis and normal controls. In conclusion, our results suggested that upregulated URAT1 protein expression might contribute to the relative urate underexcretion from the kidney of UASF. PMID:24723238

Fu, Weihua; Li, Qianwei; Yao, Jiwei; Zheng, Ji; Lang, Lang; Li, Weibing; Yan, Junan

2014-09-01

251

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

PubMed

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

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

2013-05-01

252

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

USGS Publications Warehouse

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

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

2003-01-01

253

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

PubMed

We report the first case of uric acid nephrolithiasis in a free-ranging river otter (Lontra canadensis). A 7 yr old male river otter collected from the Skagit River of western Washington (USA) had bilateral nephrolithiasis and severely enlarged ureters (one of 305 examined [0.33%]). The uroliths were 97% uric acid and 3% protein. Microscopic changes in the kidney were confined to expansion of renal calyces, minor loss of medullary tissue, and multifocal atrophy of the cortical tubules. No inflammation was observed in either kidney or the ureters. The ureters were enlarged due to marked hypertrophy of smooth muscle plus dilation of the lumen. Fusion of the major calyces into a single ureteral lumen was several cm distal to that of two adult male otters used as histopathologic control specimens. This case report is part of a large contaminant study of river otters collected from Oregon and Washington. It is important to understand diseases and lesions of the otter as part of our overall evaluation of this population. PMID:14733290

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

2003-10-01

254

Foliar applied urea improves freezing protection to avocado and peach  

Microsoft Academic Search

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

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

1996-01-01

255

Managing Urea-Containing Fertilizers1 Larry G. Bundy2  

E-print Network

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

Balser, Teri C.

256

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

Microsoft Academic Search

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

Gerhard Miirsdorf; Heinrich Kaltwasser

1989-01-01

257

Aqueous urea solution destabilizes A 1622 oligomers D. K. Klimov*  

E-print Network

considered to be the primary pathogenic agents of the Alzheimer's disease (8). The amyloidogenic pathway, formation of soluble oligomeric intermediates, and gradual accumulation of protofibrils and fibril deposits in aqueous urea solution. High concentration of urea promotes the formation of -strand structures in A 16

Straub, John E.

258

Variability of urea concentration in camel milk in Kazakhstan  

E-print Network

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

Paris-Sud XI, Université de

259

Spectrophotometric determination of urea in sugar cane distilled spirits.  

PubMed

Urea is an important precursor in the formation of ethyl carbamate, a known carcinogen in alcoholic beverages. Ethyl carbamate has recently been detected at high concentrations in sugar cane distilled spirits, but little is known about the concentration of urea in these beverages. The objectives of this study were to validate methodology for the determination of urea in sugar cane distilled spirits, to determine the levels in 68 samples from different regions within the state of Minas Gerais, Brazil, and to examine the relationship between the concentrations of urea and ethyl carbamate. The method, based on the reaction of urea with 1-phenyl-1,2-propanodione-2-oxime and spectrophotometric quantification at 540 nm, provided linear response from 0.5 to 15.0 mg/L. No purification of the sample was required. The limits of detection and quantification were 0.1 and 0.5 mg/L, respectively. Urea was detected in 69% of the samples at levels varying from 0.50 to 5.10 mg/L. There was no significant difference on the levels of urea in samples from different regions of the state. No significant correlation between the levels of urea and ethyl carbamate was observed for the samples analyzed. PMID:18553892

Labanca, Renata A; Glória, M Beatriz A

2008-07-01

260

ON-FARM TREATMENT OF STRAWS AND STOVERS WITH UREA  

Microsoft Academic Search

ON-FARM TREATMENT OF STRAWS AND STOVER WITH UREA. The nutritional value of cereal crop residues to ruminants is constrained by low N and high fibre contents. These constraints can be alleviated by treatment with alkali, the most suitable of which, for smallholder use, is urea. However, it has not widely been used in Africa. Whilst in some areas, cost and

T. SMITH

261

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

262

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

Federal Register 2010, 2011, 2012, 2013

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

2011-12-20

263

Regeneration of hemofiltrate by anodic oxidation of urea.  

PubMed

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

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

1983-05-01

264

Structure and permeation mechanism of a mammalian urea transporter  

SciTech Connect

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

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

2012-09-17

265

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

266

Simultaneous determination of ascorbic acid, uric acid and neurotransmitters with a carbon ceramic electrode prepared by sol-gel technique.  

PubMed

A sol-gel carbon composite electrode (CCE) has been prepared by mixing a sol-gel precursor (e.g. methyltrimethoxysilane) and carbon powder without adding any electron transfer mediator or specific reagents. It was demonstrated that this sensor can be used for simultaneous determination ascorbic acid, neurotransmitters (dopamine and adrenaline) and uric acid. Direct electrochemical oxidation of ascorbic acid, uric acid and catecholamines at a carbon composite electrode was investigated. The experimental results were compared with other common carbon based electrodes, specifically, boron doped diamond, glassy carbon, graphite and carbon paste electrodes. It was found that the CCE shows a significantly higher of reversibility for dopamine. In addition, in comparison to the other electrodes used, for CCE the oxidation peaks of uric acid, ascorbic acid and catecholamines in cyclic and square wave voltammetry were well resolved at the low positive potential with good sensitivity. The advantages of this sensor were high sensitivity, inherent stability and simplicity and ability for simultaneous determination of uric acid, catecholamines and ascorbic acid without using any chromatography or separation systems. The analytical performance of this sensor has been evaluated for detection of biological molecules in urine and serum as real samples. PMID:18970846

Salimi, Abdollah; Mamkhezri, Hussein; Hallaj, Rahman

2006-11-15

267

A vasodilating ?1 blocker celiprolol inhibits muscular release of uric acid precursor in patients with essential hypertension.  

PubMed

Although nonvasodilating ?1 blockers increase the levels of uric acid in serum, it is not known whether vasodilating ?1 blockers have a similar effect. In the present study, we evaluated the effect of celiprolol on the release of hypoxanthine, a uric acid precursor, from muscles after an exercise. We used the semi-ischemic forearm test to examine the release of lactate (?LAC), ammonia (?Amm), and hypoxanthine (?HX) before and 4, 10, and 60 min after an exercise in 18 hypertensive patients as well as 4 normotensive subjects. Before celiprolol treatment, all the levels of ?HX and ?Amm, and ?LAC were increased by semi-ischemic exercise in hypertensive patients, and the increases were remarkably larger than those in normotensive subjects. Celiprolol decreased both systolic and diastolic pressure. It also decreased the levels of ?HX and ?Amm without changes in ?LAC after an exercise. These findings also were confirmed by summation of each metabolite (??Metabolites). Celiprolol caused a marginal decrease of serum uric acid, but the difference was not statistically significant. On the other hand, nonvasodilating ?1 blockers did not suppress the levels of ?HX and ?Amm, whereas they significantly increased ?LAC after an exercise. Celiprolol improved energy metabolism in skeletal muscles. It suppressed HX production and consequently did not adversely affect serum uric acid levels. PMID:22893261

Mizuta, E; Utami, S B; Ohtahara, A; Endo, S; Mishima, M; Hasegawa, A; Yamada, K; Kato, M; Yamamoto, K; Ogino, K; Ninomiya, H; Miyazaki, S; Hamada, T; Taniguchi, S-i; Cheng, J; Hisatome, I

2013-01-01

268

Prevalence of hyperuricemia and relation of serum uric acid with cardiovascular risk factors in a developing country  

Microsoft Academic Search

BACKGROUND: The prevalence of hyperuricemia has rarely been investigated in developing countries. The purpose of the present study was to investigate the prevalence of hyperuricemia and the association between uric acid levels and the various cardiovascular risk factors in a developing country with high average blood pressures (the Seychelles, Indian Ocean, population mainly of African origin). METHODS: This cross-sectional health

D Conen; V Wietlisbach; P Bovet; C Shamlaye; W Riesen; F Paccaud; M Burnier

2004-01-01

269

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

PubMed

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

Arora, Kashima; Tomar, Monika; Gupta, Vinay

2014-02-21

270

Are There Any Promising Biochemical Correlates of Achievement Behavior and Motivation? The Evidence for Serum Uric Acid and Serum Cholesterol  

ERIC Educational Resources Information Center

This review examines the available evidence in support of the argument that serum uric acid (SUA) possesses considerable promise as an indicator of one type of biochemical influence on achievement behavior. The evidence arguing for further research into the role of serum cholesterol in achievement behavior is also examined. (Author/JR)

Kasl, Stanislav V.

1974-01-01

271

Trehalose protects urea-induced unfolding of ?-chymotrypsin.  

PubMed

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

Kumar, Awanish; Attri, Pankaj; Venkatesu, Pannuru

2010-11-01

272

Urea encapsulation in modified starch matrix for nutrients retention  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

273

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

PubMed Central

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

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

2013-01-01

274

Determining Glomerular Filtration Rate in Homozygous Sickle Cell Disease: Utility of Serum Creatinine Based Estimating Equations  

PubMed Central

Background Various estimating equations have been developed to estimate glomerular filtration rate (GFR) for use in clinical practice. However, the unique renal physiological and pathological processes that occur in sickle cell disease (SCD) may invalidate these estimates in this patient population. This study aims to compare GFR estimated using common existing GFR predictive equations to actual measured GFR in persons with homozygous SCD. If the existing equations perform poorly, we propose to develop a new estimating equation for use in persons with SCD. Methods 98 patients with the homozygous SS disease (55 females: 43 males; mean age 34±2.3 years) had serum measurements of creatinine, as well as had GFR measured using 99mTc-DTPA nuclear renal scan. GFR was estimated using the Modification of Diet in Renal Disease (MDRD), Cockcroft-Gault (CG), and the serum creatinine based CKD-EPI equations. The Bland-Altman limit of agreement method was used to determine agreement between measured and estimated GFR values. A SCD-specific estimating equation for GFR (JSCCS-GFR equation) was generated by means of multiple regression via backward elimination. Results The mean measured GFR±SD was 94.9±27.4 mls/min/1.73 m2 BSA, with a range of 6.4–159.0 mls/min/1.73 m2. The MDRD and CG equations both overestimated GFR, with the agreement worsening with higher GFR values. The serum creatinine based CKD-EPI equation performed relatively well, but with a systematic bias of about 45 mls/min. The new equation developed resulted in a better fit to our sickle cell disease data than the MDRD equation. Conclusion Current estimating equations, other than the CKD-EPI equation, do not perform very accurately in persons with homozygous SS disease. A fairly accurate estimating equation, suitable for persons with GFR >60 mls/min/1.73 m2 has been developed from our dataset and validated within a simulated dataset. PMID:23894560

Asnani, Monika R.; Lynch, O'Neil; Reid, Marvin E.

2013-01-01

275

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

NASA Technical Reports Server (NTRS)

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

Bruno, John G.

2013-01-01

276

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

PubMed Central

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

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

2013-01-01

277

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

PubMed Central

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

Wang, Jiajia; Tan, Xijuan; Song, Zhenghua

2013-01-01

278

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

PubMed Central

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

Stanhope, J M; Prior, I A

1975-01-01

279

Fast HPLC-ECD analysis of ascorbic acid, dehydroascorbic acid and uric acid.  

PubMed

A robust and rapid high-pressure liquid chromatography-electrochemical detection (HPLC-ECD) method was developed and validated for the accurate determination of ascorbic acid (AA) and uric acid (UA), in human plasma. Dehydroascorbic acid (DHAA) was indirectly measured by subtracting native ascorbic acid from total ascorbic acid concentrations; the latter was obtained after chemical reduction. A stable electrochemical active internal standard (homogentisic acid) was added for the accurate quantification of the analytes. The analyses were performed on a reverse-phase column with traditional HPLC and ultra-HPLC (UHPLC). The UHPLC method showed increased sensitivity with detection limit of 0.05ng for both AA and UA, 2 times lower compared to conventional HPLC. UHPLC also reduced run times fourfold with less waste generation. Both assays showed good accuracy and precision, the intra- and inter-day CVs of AA and UA analysis are less than 7%. PMID:19250886

Li, Xingnan; Franke, Adrian A

2009-04-01

280

Biological microdevice with fluidic acoustic streaming for measuring uric acid in human saliva.  

PubMed

The healthcare system requires new devices for a rapid monitoring of a patient in order to improve the diagnosis and treatment of various diseases. Accordingly, new biomedical devices are being developed. In this paper, a fully-integrated biological microdevice for uric acid analysis in human saliva is presented. It is based on optical spectrophotometric measurements and incorporates a mixture system based on acoustic streaming, that enhances the fluids reaction due to both heating and agitation generated by this effect. Acoustic streaming is provided by a piezoelectric beta-PVDF film deposited underneath the microfluidic die of the device. Further, it incorporates the electronics for the detection, readout, data processing and signal actuation. Experimental results proved that acoustic streaming based on this piezoelectric polymer is advantageous and reduces in 55% the time required to obtain the analysis results. PMID:19964879

Cardoso, V F; Catarino, S O; Martins, P; Rebouta, L; Lanceros-Mendéz, S; Minas, G

2009-01-01

281

Evaluation of a kinetic uricase method for serum uric acid assay by predicting background absorbance of uricase reaction solution with an integrated method*  

PubMed Central

A patented kinetic uricase method was evaluated for serum uric acid assay. Initial absorbance of the reaction mixture before uricase action (A 0) was obtained by correcting the absorbance at 293 nm measured before the addition of uricase solution, and background absorbance (A b) was predicted by an integrated method. Uric acid concentration in reaction solution was calculated from ?A, the difference between A 0 and A b, using the absorptivity preset for uric acid. This kinetic uricase method exhibited CV<4.3% and recovery of 100%. Lipids, bilirubin, hemoglobin, ascorbic acid, reduced glutathione and xanthine <0.32 mmol/L in serum had no significant effects. ?A linearly responded to 1.2 to 37.5 ?mol/L uric acid in reaction solution containing 15 ?l serum. The slope of linear response was consistent with the absorptivity preset for uric acid while the intercept was consistent with that for serum alone. Uric acid concentrations in clinic sera by different uricase methods positively correlated to each other. By Bland-Altman analysis, this kinetic uricase method accorded with that by quantifying the total change of UV absorbance on the completion of uricase reaction. These results demonstrated that this kinetic uricase method is reliable for serum uric acid assay with enhanced resistance to both xanthine and other common errors, wider range of linear response and much lower cost. PMID:16691645

Liao, Fei; Zhao, Yun-sheng; Zhao, Li-na; Tao, Jia; Zhu, Xiao-yun; Liu, Lan

2006-01-01

282

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

PubMed

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

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

2006-09-01

283

REACTIONS OF PEROXYNITRITE WITH URIC ACID: FORMATION OF REACTIVE INTERMEDIATES, ALKYLATED PRODUCTS AND TRIURET, AND IN VIVO PRODUCTION OF TRIURET UNDER CONDITIONS OF OXIDATIVE STRESS  

PubMed Central

Hyperuricemia is associated with hypertension, metabolic syndrome, preeclampsia, cardiovascular disease and renal disease, all conditions associated with oxidative stress. We hypothesized that uric acid, a known antioxidant, might become prooxidative following its reaction with oxidants; and, thereby contribute to the pathogenesis of these diseases. Uric acid and 1,3-15N2-uric acid were reacted with peroxynitrite in different buffers and in the presence of alcohols, antioxidants and in human plasma. The reaction products were identified using liquid chromatography-mass spectrometry (LC-MS) analyses. The reactions generate reactive intermediates that yielded triuret as their final product. We also found that the antioxidant, ascorbate, could partially prevent this reaction. Whereas triuret was preferentially generated by the reactions in aqueous buffers, when uric acid or 1,3-15N2-uric acid was reacted with peroxynitrite in the presence of alcohols, it yielded alkylated alcohols as the final product. By extension, this reaction can alkylate other biomolecules containing OH groups and others containing labile hydrogens. Triuret was also found to be elevated in the urine of subjects with preeclampsia, a pregnancy-specific hypertensive syndrome that is associated with oxidative stress, whereas very little triuret is produced in normal healthy volunteers. We conclude that under conditions of oxidative stress, uric acid can form reactive intermediates, including potential alkylating species, by reacting with peroxynitrite. These reactive intermediates could possibly explain how uric acid contributes to the pathogenesis of diseases such as the metabolic syndrome and hypertension. PMID:19219741

Gersch, Christine; Palii, Sergiu P.; Imaram, Witcha; Kim, Kyung Mee; Karumanchi, S. Ananth; Angerhofer, Alexander; Johnson, Richard J.; Henderson, George N.

2009-01-01

284

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

PubMed

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

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

2014-10-01

285

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

PubMed Central

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

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

2012-01-01

286

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

PubMed Central

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

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

2014-01-01

287

Bilirubin interference in a peroxidase-coupled procedure for creatinine eliminated by bilirubin oxidase.  

PubMed

A colorimetric peroxidase-coupled procedure for determination of creatinine in human serum and urine is described. A 30-s sample pre-treatment with bilirubin oxidase eliminates interference from endogenous bilirubin. The 4-aminoantipyrine-2-hydroxy-3,5-dichlorobenzenesulfonate chromogen system of this method is about fourfold more sensitive than current procedures that involve monitoring NAD(P)H and nearly fivefold more sensitive than the traditional picrate procedures. Incorporation of a sample blank eliminates positive interference from endogenous creatine. Results of the proposed procedure are somewhat lower than those of the common kinetic or equilibrium picrate techniques, as would be expected because of the effects of the well-known interferences in the latter methods. PMID:6744594

Artiss, J D; McEnroe, R J; Zak, B

1984-08-01

288

Creatinine Excretion Rate and Mortality in Type 2 Diabetes and Nephropathy  

PubMed Central

OBJECTIVE The creatinine excretion rate (CER) is inversely associated with mortality in the general and renal transplant population. The CER is a marker for muscle mass. It is unknown whether the CER is associated with outcome in diabetes. We therefore investigated whether the CER is a determinant of all-cause mortality in diabetic patients. RESEARCH DESIGN AND METHODS We used data from the combined Reduction of Endpoints in Non-insulin dependent diabetes mellitus with the Angiotensin II Antagonist Losartan (RENAAL) and Irbesartan Diabetic Nephropathy Trial (IDNT) studies. A total of 1,872 patients (58% of the overall population) with type 2 diabetes and nephropathy with valid 24-h urinary creatinine excretion data were included. The primary end point of the analyses was all-cause mortality. RESULTS Mean age was 60 ± 8 years and median CER was 1,407 (total range 400–3,406) mg/day. Body surface area, hemoglobin, black race, and albuminuria were positive independent determinants of the CER, whereas female sex and age were inverse independent determinants of the CER. During a median follow-up of 36 (29–45) months, 300 patients died. In a Kaplan-Meier analysis of sex-stratified tertiles of the CER, risk for all-cause mortality increased with decreasing CER (P < 0.001). In a multivariable Cox regression analysis, lower CER (as a continuous variable) was independently associated with increased risk for all-cause mortality (hazard ratio 0.39 [95% CI 0.29–0.52], P < 0.001). Adjustment for potential collection errors did not materially change these associations. CONCLUSIONS Lower CER was strongly associated with increased all-cause mortality in patients with type 2 diabetes and nephropathy. As the CER can be considered a proxy for muscle mass, this puts renewed emphasis on physical condition and exercise in this population. PMID:23300289

Sinkeler, Steef J.; Kwakernaak, Arjan J.; Bakker, Stephan J.L.; Shahinfar, Shahnaz; Esmatjes, Enric; de Zeeuw, Dick; Navis, Gerjan; Lambers Heerspink, Hiddo J.

2013-01-01

289

Cause-Specific Mortality According to Urine Albumin Creatinine Ratio in the General Population  

PubMed Central

Background Urine albumin creatinine ratio, UACR, is positively associated with all-cause mortality, cardiovascular disease and diabetes in observational studies. Whether a high UACR is also associated with other causes of death is unclear. We investigated the association between UACR and cause-specific mortality. Methods We included a total of 9,125 individuals from two population-based studies, Monica10 and Inter99, conducted in 1993–94 and 1999–2001, respectively. Urine albumin creatinine ratio was measured from spot urine samples by standard methods. Information on causes of death was obtained from The Danish Register of Causes of Death until 31 December 2010. There were a total of 920 deaths, and the median follow-up was 11.3 years. Results Multivariable Cox regression analyses with age as underlying time axis showed statistically significant positive associations between UACR status and risk of all-cause mortality, endocrine nutritional and metabolic diseases, mental and behavioural disorders, diseases of the circulatory system, and diseases of the respiratory system with hazard ratios 1.56, 6.98, 2.34, 2.03, and 1.91, for the fourth UACR compared with the first, respectively. Using UACR as a continuous variable, we also found a statistically significant positive association with risk of death caused by diseases of the digestive system with a hazard ratio of 1.02 per 10 mg/g higher UACR. Conclusion We found statistically significant positive associations between baseline UACR and death from all-cause mortality, endocrine nutritional and metabolic diseases, and diseases of the circulatory system and possibly mental and behavioural disorders, and diseases of the respiratory and digestive system. PMID:24675825

Skaaby, Tea; Husemoen, Lise Lotte Nystrup; Ahluwalia, Tarunveer Singh; Rossing, Peter; J?rgensen, Torben; Thuesen, Betina Heinsbaek; Pisinger, Charlotta; Rasmussen, Knud; Linneberg, Allan

2014-01-01

290

Predictive model for segmented poly(urea)  

NASA Astrophysics Data System (ADS)

Segmented poly(urea) has been shown to be of significant benefit in protecting vehicles from blast and impact and there have been several experimental studies to determine the mechanisms by which this protective function might occur. One suggested route is by mechanical activation of the glass transition. In order to enable design of protective structures using this material a constitutive model and equation of state are needed for numerical simulation hydrocodes. Determination of such a predictive model may also help elucidate the beneficial mechanisms that occur in polyurea during high rate loading. The tool deployed to do this has been Group Interaction Modelling (GIM) - a mean field technique that has been shown to predict the mechanical and physical properties of polymers from their structure alone. The structure of polyurea has been used to characterise the parameters in the GIM scheme without recourse to experimental data and the equation of state and constitutive model predicts response over a wide range of temperatures and strain rates. The shock Hugoniot has been predicted and validated against existing data. Mechanical response in tensile tests has also been predicted and validated.

Gould, P. J.; Cornish, R.; Frankl, P.; Lewtas, I.

2012-08-01

291

Serum cystatin C predicts vancomycin trough levels better than serum creatinine in hospitalized patients: a cohort study  

PubMed Central

Introduction Serum cystatin C can improve glomerular filtration rate (GFR) estimation over creatinine alone, but whether this translates into clinically relevant improvements in drug dosing is unclear. Methods This prospective cohort study enrolled adults receiving scheduled intravenous vancomycin while hospitalized at the Mayo Clinic in 2012. Vancomycin dosing was based on weight, serum creatinine with the Cockcroft-Gault equation, and clinical judgment. Cystatin C was later assayed from the stored serum used for the creatinine-based dosing. Vancomycin trough prediction models were developed by using factors available at therapy initiation. Residuals from each model were used to predict the proportion of patients who would have achieved the target trough with the model compared with that observed with usual care. Results Of 173 patients enrolled, only 35 (20%) had a trough vancomycin level within their target range (10 to 15 mg/L or 15 to 20 mg/L). Cystatin C-inclusive models better predicted vancomycin troughs than models based upon serum creatinine alone, although both were an improvement over usual care. The optimal model used estimated GFR by the Chronic Kidney Disease Epidemiology Collaborative (CKD-EPI) creatinine-cystatin C equation (R2?=?0.580). This model is expected to yield 54% (95% confidence interval 45% to 61%) target trough attainment (P <0.001 compared with the 20% with usual care). Conclusions Vancomycin dosing based on standard care with Cockcroft-Gault creatinine clearance yielded poor trough achievement. The developed dosing model with estimated GFR from CKD-EPIcreatinine-cystatin C could yield a 2.5-fold increase in target trough achievement compared with current clinical practice. Although this study is promising, prospective validation of this or similar cystatin C-inclusive dosing models is warranted. PMID:24887089

2014-01-01

292

Formation of urea and guanidine by irradiation of ammonium cyanide.  

NASA Technical Reports Server (NTRS)

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.

Lohrmann, R.

1972-01-01

293

Urea photosynthesis inside polyelectrolyte capsules: effect of confined media.  

PubMed

The influence of the restricted volume of poly(styrene sulfonate)/poly(allylamine hydrochloride) capsules of different size (2.2, 4.2, and 8.1 microm) on the TiO2-assisted photosynthesis of urea from inorganic precursors (CO2 and NO(3-)) in aqueous solution was demonstrated. Poly(vinyl alcohol) was employed as electron donor to facilitate the photosynthetic process. Decreasing the size of the confined microvolume of polyelectrolyte capsules accelerates the NO(3-) photoreduction, which is a limiting stage of the urea photosynthesis and, correspondingly, increases the efficiency of urea production. The highest yield of urea photosynthesis (37%) was achieved for Cu-modified TiO2 nanoparticles encapsulated inside 2.2 microm poly(styrene sulfonate)/poly(allylamine hydrochloride) capsules. PMID:15924493

Shchukin, Dmitry G; Möhwald, Helmuth

2005-06-01

294

IRIS Toxicological Review of Urea (Interagency Science Discussion Draft)  

EPA Science Inventory

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

295

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

NASA Technical Reports Server (NTRS)

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

Geiger, P. J.

1969-01-01

296

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. ...

297

67 FR 78713 - Urea: Revocation of Tolerance Exemptions  

Federal Register 2010, 2011, 2012, 2013

...This exemption is for its use as an adjuvant/intensifer for herbicides. 3. Another exemption from the requirement...d) the entry for urea ``use as an adjuvant/intensifier for herbicides.'' iii. Removing from the table...

2002-12-26

298

Crystal Structure of Urea Carboxylase Provides Insights into the Carboxyltransfer Reaction*S  

E-print Network

in many bacteria, algae, and fungi and catalyzes the conversion of urea to allophanate, an essential step, fungi, algae, and bacteria possess an enzymatic activity that converts urea to ammonium, enabling them to uti- lize urea as a nitrogen source (1­3). In agriculture, urea is widely used as a fertilizer

Tong, Liang

299

Curing process of phenol-urea-formaldehyde-tannin (PUFT) adhesives  

Microsoft Academic Search

Summary  Phenol-urea-formaldehyde-tannin (PUFT) adhesives have been prepared by copolymerization at room temperature of pine bark tannins\\u000a with phenol-urea-formaldehyde (PUF) prepolymers prepared under varying operating conditions. Differential scanning calorimetry\\u000a (DSC) and dynamic mechanical analysis (DMA) have been used to analyse the curing of prepolymers and adhesives. DSC curves\\u000a were obtained at three different heating rates and, by means of the Model Free

G. Vázquez; F. López-Suevos; J. González-Alvarez; G. Antorrena

2005-01-01

300

UREA LEVELS AND SUPPLEMENTAL ENERGY SOURCES IN SUGARCANE DIETS I  

Microsoft Academic Search

Two experiments, each involving a digestion-N balance trial and a feedlot trial, determined the replacement value of urea-corn meal (UC) for cottonseed meal (CSM) and the value of mo- lasses in sugarcane diets. Steers fed 70% sugarcane-30% concentrate diets with O, 28 or 56% of the dietary N as urea had a slight reduction (P<.28) in dry matter (DM) intake

F. M. Pate; P. M. Fairhurst; J. T. K. Munthali

301

Urea reduction of NO\\/sub x\\/ in combustion effluents  

Microsoft Academic Search

Method is claimed for reducing NO\\/sub x\\/ in combustion effluents by introducing urea at elevated temperatures in the presence of oxygen, either as a solid or solution in amounts sufficient to reduce the NO\\/sub x\\/ concentration. Conveniently, the urea may be introduced as a solid powder or as a solution in a hydroxylic solvent, at temperatures in excess of 1300°

J. K. Arand; L. J. Muzio; J. G. Sotter

1980-01-01

302

Influence of herbicides on transformations of urea nitrogen in soil  

Microsoft Academic Search

The influence of 28 formulated herbicides on transformations of urea nitrogen in soil was studied by determining the effects of 5 and 50 mg active ingredient kg soil of each herbicide on the amounts of urea hydrolyzed and the amounts of nitrite and nitrate produced when samples of two coarse?textured soils and two fine?textured soils were incubated aerobically at 20°C

D. A. Martens; J. M. Bremner

1993-01-01

303

Structural changes in urea-formaldehyde resins during storage  

Microsoft Academic Search

13  C NMR spectroscopy. The three-step synthesis produces the resin consisting of two parts: the polymeric part from condensation\\u000a of formaldehyde with first amount of urea, and monomeric part formed after addition of second part of urea. Some differences\\u000a in structure depending on details of synthesis are of temporary character and level mainly in transhydroxymethylation from\\u000a polymeric to monomeric part of

P. Christjanson; K. Siimer; T. Pehk; I. Lasn

2002-01-01

304

Sensitivity to Urea Fertilization in Three Amphibian Species  

Microsoft Academic Search

Forest fertilization with granular urea is a well-established management practice in many forested regions of the world. We\\u000a hypothesize that chemical forest fertilizers may be affecting forest-dwelling wildlife. In the laboratory, we studied the\\u000a effects of fertilization doses of granular urea on three species of forest-dwelling amphibians (Plethodon vehiculum, Rhyacotriton variegatus, and Taricha granulosa). In avoidance experiments, the three species

A. Marco; D. Cash; L. K. Belden; A. R. Blaustein

2001-01-01

305

Urea secretion by the straight segment of the proximal tubule.  

PubMed Central

Studies utilizing in vitro microperfusion were designed to examine whether urea is actively or passively transported across superficial and juxtamedullary straight segments of rabbit proximal tubules. With perfusate and bath solutions containing 1 mM urea and electrolytes similar to normal plasma, the efflux (lumen-to-bath) isotopic permeability (X 10(-5) cm s-1) of superficial segments was 1.37 +/- 0.16 and of juxtamedullary segments was 2.14 +/- 0.20. In the same tubules, the influx (bath-to-lumen) isotopic permeability was 3.70 +/- 0.35 in superficial segments and 4.75 +/- 0.37 in juxtamedullary segments. Despite net water movement in the opposite direction (0.5 nl mm-1 min-1), the influx rate was significantly higher than the efflux rate of urea in both groups. With a low perfusion rate (2 nl/min) and equivalent specific activities of [14C]urea in bath and perfusate, the collected-to-perfused ratio of [14C]urea, corrected for volume marker change, was 1.07 +/- 0.01 in superficial and 1.09 +/- 0.01 in juxtamedullary nephrons, thus indicating net secretion in both segments. In separate studies urea influx was inhibited by hypothermia (decrease from 37 degrees to 28 degrees C), by phloretin (0.1 mM in bath), by cyanide (1 mM), but not by probenecid (0.2 mM). In each case the inhibition was highly significant and reversible. These data suggest that urea is actively secreted by the straight segments of both the superficial and juxtamedullary proximal tubules. These segments may, therefore, contribute significantly to the high urea concentration found at the bend of Henle's loop by micropuncture. PMID:956389

Kawamura, S; Kokko, J P

1976-01-01

306

Urea and ureolytic activity in lakes of different trophic status.  

PubMed

Urea and uraease (U-ase) activity were determined in water samples taken from the surface layers of 17 lakes of different trophic status. Urea concentrations were inversely correlated with the trophic status of the studied lakes and varied from below the detection limit to 25 micromol l(-1). Maximal potential ureolytic activity (V(max)) ranged from 0.2 to 7.0 micromol l(-1) h(-1). The highest urea concentrations and the lowest U-ase activities were recorded in the spring, whereas the lowest urea concentrations and the highest rates of urea hydrolysis were observed late in summer, during heavy phytoplankton blooms. Since in the majority of the Great Mazurian Lakes microplankton growth was limited by nitrogen supply, urea was an important N source for both auto- and heterotrophic planktonic microorganisms throughout the growth period. U-ase activity was mainly related to the seston. Only up to 25% of total activity could be attributed to free enzymes dissolved in lake water. In epilimnetic water samples the bulk of the ureolytic activity originated from seston-attached bacteria. However, a positive, statistically significant correlation between ureolytic activity and chlorophyll a (Chl(a)) concentrations suggests that phytoplankton may also be responsible for at least a some of the observed ureolytic activity in the highly eutrophic Great Mazurian Lakes. PMID:17338274

Siuda, Waldemar; Chróst, Ryszard J

2006-01-01

307

NiO nanoparticle-based urea biosensor.  

PubMed

NiO nanoparticles (NiO-NPs) have been exploited successfully for the fabrication of a urea biosensor. A thin film of NiO nanoparticles deposited on an indium tin oxide (ITO) coated glass substrate serves as an efficient matrix for the immobilisation of urease (Ur), the specific enzyme for urea detection. The prepared bioelectrode (Ur/NiO-NP/ITO/glass) is utilised for urea sensing using cyclic voltammetry and UV-visible spectroscopy. NiO nanoparticles act as electro-catalytic species that are based on the shuttling of electrons between Ni(2+) and Ni(3+) in the octahedral site and result in an enhanced electrochemical current response. The prepared bioelectrode (Ur/NiO-NPs/ITO/glass) exhibits a high sensitivity of 21.3 ?A/(mM (*) cm(2)) and a good linearity in a wide range (0.83-16.65 Mm) of urea concentrations with fast response time of 5s. The low value of the Michaelis-Menten constant (K(m)=0.34 mM) indicates the high affinity of Ur towards the analyte (urea). The high catalytic activity, along with the redox behaviour of NiO-NPs, makes it an efficient matrix for the realisation of a urea biosensor. PMID:22947517

Tyagi, Manisha; Tomar, Monika; Gupta, Vinay

2013-03-15

308

Use of urea–molasses–multinutrient block and urea-treated rice straw for improving dairy cattle productivity in Vietnam  

Microsoft Academic Search

After conducting a preliminary survey, a feeding trial was carried out to determine the effect of urea–molasses–multinutrient block (UMMB) and urea-treated rice straw (UTRS) as a feed supplement on the productivity of dairy cows. Sixty Holstein–Friesian crossbred cows on 11 smallholder farms were divided equally into control, UMMB and UTRS supplementation groups. Milk yield and feed intake were recorded daily.

Doan Duc Vu; Le Xuan Cuong; Chung Anh Dung; Pham Ho Hai

1999-01-01

309

Lactate: creatinine ratio in babies with thin meconium staining of amniotic fluid  

PubMed Central

Background ACOG states meconium stained amniotic fluid (MSAF) as one of the historical indicators of perinatal asphyxia. Thick meconium along with other indicators is used to identify babies with severe intrapartum asphyxia. Lactate creatinine ratio (L: C ratio) of 0.64 or higher in first passed urine of babies suffering severe intrapartum asphyxia has been shown to predict Hypoxic Ischaemic Encephalopathy (HIE). Literature review shows that meconium is passed in distress and thin meconium results from mixing and dilution over time, which may be hours to days. Thin meconium may thus be used as an indicator of antepartum asphyxia. We tested L: C ratios in a group of babies born through thin and thick meconium, and for comparison, in a group of babies without meconium at birth. Methods 86 consecutive newborns, 36 to 42 weeks of gestation, with meconium staining of liquor, were recruited for the study. 52 voided urine within 6 hours of birth; of these 27 had thick meconium and 25 had thin meconium at birth. 42 others, who did not have meconium or any other signs of asphyxia at birth provided controls. Lactate and creatinine levels in urine were tested by standard enzymatic methods in the three groups. Results Lactate values are highest in the thin MSAF group followed by the thick MSAF and controls. Creatinine was lowest in the thin MSAF, followed by thick MSAF and controls. Normal babies had an average L: C ratio of 0.13 (± 0.09). L: C ratio was more among thin MSAF babies (4.3 ± 11.94) than thick MSAF babies (0.35 ± 0.35). Median L: C ratio was also higher in the thin MSAF group. Variation in the values of these parameters is observed to be high in the thin MSAF group as compared to other groups. L: C ratio was above the cutoff of 0.64 of Huang et al in 40% of those with thin meconium. 2 of these developed signs of HIE with convulsions (HIE Sarnat and Sarnat Stage II) during hospital stay. One had L: C Ratio of 93 and the other of 58.6. A smaller proportion (20%) of those with thick meconium had levels above the cutoff and 2 developed HIE and convulsions with L: C ratio of 1.25 and 1.1 respectively. Conclusion In evolving a cutoff of L: C ratios that would be highly sensitive and specific (0.64), Huang et al studied it in a series of babies with severe intrapartum asphyxia. Our study shows that the specificity may not be as good if babies born through thin meconium are also included. L: C ratios are much higher in babies with thin meconium. It may be that meconium alone is not a good indicator of asphyxia and the risk of HIE. However, if the presence of meconium implies asphyxia then perhaps a higher cut-off than 0.64 is needed. L: C ratios should be tested in a larger sample that includes babies with thin meconium, before L: C ratios can be applied universally. PMID:16626486

Ojha, Rishi Kant; Singh, Saroj K; Batra, Sanjay; Sreenivas, V; Puliyel, Jacob M

2006-01-01

310

Changes in Uric Acid Levels following Bariatric Surgery Are Not Associated with SLC2A9 Variants in the Swedish Obese Subjects Study  

PubMed Central

Context and Objective Obesity and SLC2A9 genotype are strong determinants of uric acid levels. However, data on SLC2A9 variants and weight loss induced changes in uric acid levels are missing. We examined whether the changes in uric acid levels two- and ten-years after weight loss induced by bariatric surgery were associated with SLC2A9 single nucleotide polymorphisms (SNPs) in the Swedish Obese Subjects study. Methods SNPs (N?=?14) identified by genome-wide association studies and exonic SNPs in the SLC2A9 gene locus were genotyped. Cross-sectional associations were tested before (N?=?1806), two (N?=?1664) and ten years (N?=?1201) after bariatric surgery. Changes in uric acid were compared between baseline and Year 2 (N?=?1660) and years 2 and 10 (N?=?1172). A multiple testing corrected threshold of P?=?0.007 was used for statistical significance. Results Overall, 11 of the 14 tested SLC2A9 SNPs were significantly associated with cross-sectional uric acid levels at all three time points, with rs13113918 showing the strongest association at each time point (R2?=?3.7?5.2%, 3.9×10?22?p?7.7×10?11). One SNP (rs737267) showed a significant association (R2?=?0.60%, P?=?0.002) with change in uric acid levels from baseline to Year 2, as common allele homozygotes (C/C, N?=?957) showed a larger decrease in uric acid (?61.4 µmol/L) compared to minor allele carriers (A/X: ?51.7 µmol/L, N?=?702). No SNPs were associated with changes in uric acid from years 2 to 10. Conclusions SNPs in the SLC2A9 locus contribute significantly to uric acid levels in obese individuals, and the associations persist even after considerable weight loss due to bariatric surgery. However, we found little evidence for an interaction between genotype and weight change on the response of uric acid to bariatric surgery over ten years. Thus, the fluctuations in uric acid levels among the surgery group appear to be driven by the weight losses and gains, independent of SLC2A9 genotypes. PMID:23272134

Sarzynski, Mark A.; Jacobson, Peter; Rankinen, Tuomo; Carlsson, Bjorn; Sjostrom, Lars; Bouchard, Claude; Carlsson, Lena M. S.

2012-01-01

311

Inflammatory status hepatic enzymes and serum creatinine in HIV-, HIV+ and HIV-TB co-infected adult Central Africans  

PubMed Central

Background and aim Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome is a major public health issue in Africa. The objective of this study was to determine which of isolated HIV-infection, isolated naive pulmonary tuberculosis (PTB), or naive HIV-PTB coinfection was more harmful to inflammatory, hepatic, and renal functions. Methods This cross-sectional study was undertaken among ten patients with isolated HIV infection, ten patients with isolated naive HIV infection, ten patients with isolated PTB and 32 patients with HIV-PTB coinfection, with the aim of determining which group had the highest levels of oxidative stress and hepatic and renal dysfunction markers. Serum aminotransferase (AST), alanine transferase (ALT), gamma-glutamyl transferase (GGT), and creatinine measurements were compared across the three groups of patients, who were managed from admission in the pulmonology division of the Brazzaville Teaching Hospital, Congo. Results HIV patients had the highest levels of ALT, GGT, and creatinine before and after adjusting for age and sex. Adjusted levels of AST, ALT, GGT, and creatinine were higher in HIV-PTB coinfection patients than in sero-negative PTB patients. Conclusion There is a significant association between HIV infection and increase in concentration of ALT, GGT, and creatinine. PMID:23204860

Mokondjimobe, Etienne; Longo-Mbenza, Benjamin; Mampouya-Arrouse, Patou; Parra, Henri Joseph; Diatewa, Martin

2012-01-01

312

Simultaneous determination of urinary creatinine and metabolites of toluene, xylene, styrene, ethylbenzene and phenol by automated high performance liquid chromatography  

Microsoft Academic Search

Summary An attempt was made to establish a method for the direct determination of urinary concentrations of creatinine, hippuric acid, methylhippuric acid and mandelic acid by automated high performance liquid chromatography (HPLC). Urine was diluted with distilled water or mobile phase, then the mixture was centrifuged and the supernatant was injected into HPLC. A stainless-steel column packed with octadecyl silanized

Masana Ogata; Toyohiro Taguchi

1988-01-01

313

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

ERIC Educational Resources Information Center

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

Diamandis, E. P.; And Others

1983-01-01

314

Elimination of Endogenous Toxin, Creatinine from Blood Plasma Depends on Albumin Conformation: Site Specific Uremic Toxicity & Impaired Drug Binding  

Microsoft Academic Search

Uremic syndrome results from malfunctioning of various organ systems due to the retention of uremic toxins which, under normal conditions, would be excreted into the urine and\\/or metabolized by the kidneys. The aim of this study was to elucidate the mechanisms underlying the renal elimination of uremic toxin creatinine that accumulate in chronic renal failure. Quantitative investigation of the plausible

Ankita Varshney; Mohd Rehan; Naidu Subbarao; Gulam Rabbani; Rizwan Hasan Khan; Collin Stultz

2011-01-01

315

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

PubMed

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

Kunert, Christof; Walker, Alesia; Hofmann, Thomas

2011-08-10

316

Risk of Developing Low Glomerular Filtration Rate or Elevated Serum Creatinine in a Screened Cohort in Okinawa, Japan  

Microsoft Academic Search

There are no known predictors of renal dysfunction, particularly for a community-based screening. We evaluated the changes in serum creatinine (SCr) and glomerular filtration rate (GFR) among screenees who participated in the screening program of the Okinawa General Health Maintenance Association both in 1983 and 1993. A total of 4,662 screenees at least 30 years of age at the 1983

Kunitoshi Iseki; Chiho Iseki; Yoshiharu Ikemiya; Kozen Kinjo; Shuichi Takishita

2007-01-01

317

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

Microsoft Academic Search

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

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

1995-01-01

318

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

PubMed

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

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

2015-02-01

319

Analysis of tacrolimus and creatinine from a single dried blood spot using liquid chromatography tandem mass spectrometry  

PubMed Central

Long term therapeutic drug monitoring and assessment of renal function are required in renal transplant recipients on immunosuppressant therapy such as tacrolimus. Dry blood spots (DBS) have been used successfully in the clinic for many years and offers a convenient, simple and non-invasive method for repeated blood tests. We developed and performed a preliminary validation of a method for the analysis of tacrolimus and creatinine from a single DBS using liquid chromatography-tandem mass spectrometric (LC–MS/MS). Tacrolimus and creatinine were extracted from a 6 mm punch with a mixture of methanol/acetonitrile containing ascomycin and deuterated creatinine as internal standards. A 10 ?l aliquot of the extract was analyzed directly after dilution for creatinine with normal phase high performance liquid chromatography and multiple reaction monitoring. The remainder of the extract was processed and analyzed for tacrolimus. The lower limit of quantification for tacrolimus was 1 ng/ml with accuracy of 0.34% bias and precision (CV) of 11.1%. The precision ranged from 1.33% to 7.68% and accuracy from ?4.44% to 11.6% bias for the intra- and inter-day analysis. The lower limit of quantification of creatinine was 0.01 mg/dL with precision of 7.94%. Accuracy was based on recovery of additional creatinine spiked into whole blood samples and ranged from ?2.45% bias at 5 mg/dL to 3.75% bias at 0.5 mg/dL. Intra- and inter-day precision was from 3.48 to 4.11%. The assay was further validated with DBS prepared from pediatric renal transplant recipients. There was excellent correlation between the levels of tacrolimus and creatinine obtained from the clinical laboratory and the DBS method developed. After additional validation, this assay may have a significant impact on compliance with medication intake as well as potentially lowering the cost associated with intravenous blood draws in clinical laboratories. PMID:23548676

Koop, Dennis R.; Bleyle, Lisa A.; Munar, Myrna; Cherala, Ganesh; Al-Uzri, Amira

2014-01-01

320

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

PubMed Central

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

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

2013-01-01

321

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

PubMed Central

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

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

2014-01-01

322

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

PubMed Central

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

2014-01-01

323

Significant association of serum uric acid levels with SLC2A9 rs11722228 among a Japanese population  

Microsoft Academic Search

Genome-wide association studies identified that SLC2A9 (GLUT9) gene polymorphisms were associated with serum uric acid (SUA) levels. Among the Japanese, a C\\/T polymorphism in intron 8 (rs11722228) was reported to be highly significant, though the function and strength of association were unknown. This study aimed to confirm the association, estimating the means of SUA according to the genotype, as well

Nobuyuki Hamajima; Rieko Okada; Sayo Kawai; Asahi Hishida; Emi Morita; Guang Yin; Kenji Wakai; Hirotaka Matsuo; Hiroki Inoue; Yuzo Takada; Yatami Asai; Atsuyoshi Mori; Mariko Naito

2011-01-01

324

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

Microsoft Academic Search

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

Yuzo Kayamori; Yoshiaki Katayama; Tatsuo Matsuyama; Takeyoshi Urata

1997-01-01

325

Effects of Aerobic Exercise on Uric Acid, Total Antioxidant Activity, Oxidative Stress, and Nitric Oxide in Human Saliva  

Microsoft Academic Search

The aim of this study was to determine the effect of aerobic exercise on uric acid (UA), total antioxidant activity (TAA), lipid hydroperoxides, and nitric oxide (NO) metabolites in human saliva. Twenty-four healthy male and female subjects were studied during a 10,000-m race. Saliva samples were collected 1 h before and immediately after exercise. The NO concentration was determined by

David González; Ramón Marquina; Norelis Rondón; Antonio J. Rodríguez-Malaver; Rafael Reyes

2008-01-01

326

Segmented poly(esterurethane urea)s from novel urea-diol chain extenders: synthesis, characterization and in vitro biological properties.  

PubMed

This work describes the preparation, physicochemical characterization, mechanical properties and in vitro biological properties of two bioresorbable aliphatic segmented poly(esterurethane urea)s (SPEUU) based on poly(epsilon-caprolactone) diol (PCL diol), 1,6-hexamethylene diisocyanate and two novel urea-diol chain extenders. To strengthen the interactions through hydrogen bonding in the hard segments of SPEUU, novel chain extenders containing urea groups were synthesized and used in the SPEUU formulation. The different chemical structures of the chain extenders modulated the phase separation of soft and hard segments, as demonstrated by the thermal behavior. The hard segment association was enhanced using a diurea-diol chain extender. The biological interactions between the obtained materials and blood were studied by in vitro methods. Research on the protein adsorption, platelet adhesion and thrombus formation is presented. Studies of protein adsorption onto polymeric surfaces showed that SPEUU adsorbed more albumin than fibrinogen. Studies on platelet adhesion and thrombus formation of SPEUU-coated coverslips indicated the antithrombogenic behavior of these surfaces. The synthesized SPEUU revealed no signs of cytotoxicity to Chinese hamster ovary cells, showing satisfactory cytocompatibility. PMID:18359673

Caracciolo, P C; de Queiroz, A A A; Higa, O Z; Buffa, F; Abraham, G A

2008-07-01

327

Urinary cortisol:creatinine ratios in healthy horses and horses with hyperadrenocorticism and non-adrenal disease.  

PubMed

Urinary cortisol and creatinine concentrations, and the cortisol:creatinine ratio were compared between 12 healthy horses (group 1), 13 horses with Cushing's disease (group 2), and eight horses with dysautonomia syndrome (equine grass sickness) (group 3). The mean (sd) urinary cortisol concentrations were 112 (55.7), 250 (357) and 864 (526) nmol/litre in groups 1, 2 and 3, respectively; the mean (sd) urinary creatinine concentrations were 18.9 (7.3), 12.0 (6.7) and 45.2 (26.4) nmol/litre in groups 1, 2 and 3, respectively, and the mean (sd) ratios were 6.1 (2.6), 19.8 (23.8) and 21.3 (14.5) (x 10(-6)) in groups 1, 2 and 3, respectively. The urinary cortisol and creatinine concentrations were significantly greater in group 3 than in groups 1 and 2, but the ratios were not significantly different, although there was a trend (P=0.076) towards higher values in groups 2 and 3. A diagnostic cut-off in the cortisol:creatinine ratio for the confirmation of Cushing's disease of more than 6.9 x 10(-6) was associated with a diagnostic sensitivity and specificity of 92.3 and 75.0 per cent, respectively, when compared with healthy horses. However, when group 3 horses were included, a cut-off of more than 7.4 x 10(-6) was associated with a diagnostic sensitivity and specificity of 84.6 and 54.5 per cent, respectively. PMID:12135071

Chandler, K J; Dixon, R M

2002-06-22

328

Conventional and planar chip sensors for potentiometric assay of uric acid in biological fluids using flow injection analysis.  

PubMed

The potentiometric response properties of several PVC-based membrane sensors using phthalocyanine complexes of cobalt(II) (CoPC) and Fe(II) (FePC) as anion carriers, towards uric acid were constructed and characterized. The sensors demonstrated fast near-Nernstian response for uric acid over the concentration ranges 9.1 x 10(-6) to 9.1 x 10(-2) and 3.1 x 10(-5) to 3.1 x 10(-2)M with detection limits 0.67 and 2.85 microg mL(-1) over pH 6.5-8 for CoPC and FePC based membrane sensors plasticized with o-NPOE and 1% TDMAC, respectively. A novel solid-state planar chip urate sensor was developed, characterized according to IUPAC recommendations, easily used in a single channel wall-jet flow injection system and compared with a tubular detector. The intrinsic characteristics of the detectors in a low dispersion manifold were determined and compared with data obtained under hydrodynamic mode of operation. Validation of the assay methods with the proposed sensors by measuring the lower limit, range, accuracy, precision, repeatability and between-day-variability revealed good performance characteristics confirming applicability for continuous determination of uric acid. The sensors were used for determining urate in biological fluids at an input rate of 50 samples per hour. The results compare favorably with data obtained by the standard spectrophotometry. PMID:17604587

Kamel, Ayman H

2007-10-18

329

Serum uric acid level in newly diagnosed essential hypertension in a Nepalese population: A hospital based cross sectional study  

PubMed Central

Objective To develop the missing link between hyperuricemia and hypertension. Methods The study was conducted in Department of Biochemistry in collaboration with Nephrology Unit of Internal Medicine Department. Hypertension was defined according to blood pressure readings by definitions of the Seventh Report of the Joint National Committee. Totally 205 newly diagnosed and untreated essential hypertensive cases and age-sex matched normotensive controls were enrolled in the study. The potential confounding factors of hyperuricemia and hypertension in both cases and controls were controlled. Uric acid levels in all participants were analyzed. Results Renal function between newly diagnosed hypertensive cases and normotensive healthy controls were adjusted. The mean serum uric acid observed in newly diagnosed hypertensive cases and in normotensive healthy controls were (290.05±87.05) µmol/L and (245.24±99.38) µmol/L respectively. A total of 59 (28.8%) participants of cases and 28 (13.7%) participants of controls had hyperuricemia (odds ratio 2.555 (95% CI: 1.549-4.213), P<0.001). Conclusions The mean serum uric acid levels and number of hyperuricemic subjects were found to be significantly higher in cases when compared to controls. PMID:24144132

Poudel, Bibek; Yadav, Binod Kumar; Kumar, Arun; Jha, Bharat; Raut, Kanak Bahadur

2014-01-01

330

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

PubMed Central

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

2014-01-01

331

Interaction of Obesity and Central Obesity on Elevated Urinary Albumin-to-Creatinine Ratio  

PubMed Central

Background Microalbuminuria was much more common among obese individuals indicating a probable association with obesity. However, association of microalbuminuria with interaction between obesity and central obesity has not yet been studied. Design and Methods A cross-sectional study was conducted in a 2889 general population aged ?30 years. Obesity was defined as body mass index ?28.0 kg/m2 and central obesity was defined as waist-to-hip ratio ?0.85 for females and ?0.90 for males. Both additive and multipliable interactions between obesity and central obesity on elevated urinary albumin-to-creatinine ratio (UACR) were evaluated. Results After controlling for potential covariates, participants with both obesity and central obesity have significantly increased risk for elevated UACR (OR?=?1.82 P<0.001) compared to those with neither. Additive interaction analysis indicated that about 43.9% of the risk of elevated UACR in participants with both obesity and central obesity was attributed to the interaction between obesity and central obesity (the attributable proportion because of the interaction: 0.439; 95% CI: 0.110–0.768). The multipliable interactive effect between obesity and central obesity on elevated UACR was not found significant (OR?=?1.82, P?=?0.078). Conclusions Microalbuminuria was significantly associated with the interaction between obesity and central obesity. Our results indicated that individuals with both obesity and central obesity should be intensively managed to prevent renal diseases. PMID:24892930

Zhang, Qiu; Tian, Honggang; Li, Hongmei

2014-01-01

332

Crystal structure of a bacterial homologue of the kidney urea transporter  

SciTech Connect

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

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

2010-03-19

333

Predialysis urea concentration is sufficient to characterize hemodialysis adequacy.  

PubMed

Mathematical description of urea kinetics for a week showed that, under steady state conditions (i.e., total removal equals total synthesis), any predialysis urea concentration is expressed as a linear function of specific urea generation (G/V) and of dialysis schedule timing and sessional Kt/V (product of clearance, K, and session time, t, divided by the urea distribution volume, V). It also predicts that TACurea is proportional to the predialysis concentrations. The ratio between the two depends linearly on delivered weekly dialysis dose ([wDD] = T(G/V)/TACurea, with T the number of hours in 1 week). These hypotheses have been tested by retrospectively analyzing urea kinetc modelling data that include all predialysis and post dialysis concentrations of 163 patient-weeks. All patients were anuric, and dialysis frequency was thrice weekly. Accuracy is assessed with regression analysis between database numbers and computed values. The theoretical ratio between midweek concentration and TACurea (1.43) is close to the computed ratio (1.46, r2 = 0.909). TACurea (slope = 1.002, r2 = 0.997), specific generation rate G/V as a precursor to PCRn (slope = 1.007, r2 = 0.985), and wDD (slope = 1.002, r2 = 0.909) are all accurately computed from predialysis concentrations. To aid in the determination of the ratio for the different predialysis, concentrations using wDD a nomogram is included. PMID:9804519

De Wachter, D S; Brems, S; Vanholder, R; Verdonck, P R; Hombrouckx, R O

1998-01-01

334

Sensitivity to urea fertilization in three amphibian species.  

PubMed

Forest fertilization with granular urea is a well-established management practice in many forested regions of the world. We hypothesize that chemical forest fertilizers may be affecting forest-dwelling wildlife. In the laboratory, we studied the effects of fertilization doses of granular urea on three species of forest-dwelling amphibians (Plethodon vehiculum, Rhyacotriton variegatus, and Taricha granulosa). In avoidance experiments, the three species avoided a substrate treated with a dose of 225 kg N/ha urea. In toxicity experiments, we exposed amphibians to urea at doses of 225 kg N/ha and 450 kg N/ha for 4 days. The observed effects increased with time and dose, and there were significant differences in sensitivity among the species. Both treatment levels had an acute effect on survival of P. vehiculum and R. variegatus. At 24 h, mortality at the highest dose was 67% for P. vehiculum, and 47% for R. variegatus. In contrast, there was no mortality for T. granulosa at these concentrations. We suggest that environmental levels of urea could be affecting behavior and survival of some amphibians species in fertilized forests. PMID:11443373

Marco, A; Cash, D; Belden, L K; Blaustein, A R

2001-04-01

335

Application of Individualized Bayesian Urea Kinetic Modeling to pediatric hemodialysis.  

PubMed

Incorporating urea rebound using equilibrated urea concentration (Ceq) after hemodialysis (HD) is essential for accurate assessment of HD efficiency. It is impractical to measure Ceq in clinical settings, and there are no recommended methodologies to predict Ceq in children. The objective of this work is to assess the ability of an Individualized Bayesian Urea Kinetic Model (IBKM) for predicting Ceq in children receiving HD. Developed based on adult HD data, the IBKM is a two-pool urea kinetic model that calculates Bayesian estimates of individual Ceq. Blood urea nitrogen (BUN) samples from 30 HD sessions in 13 children (age 12-18 years) were taken at pre-HD, immediately post-HD, and 60 minutes post-HD (Ceq). The IBKM and estimated population parameters from adult data were fitted to the observed data from children to predict individual Ceq using NONMEM VI software in comparison with observed Ceq (9.5 +/- 3.8 mmol/L), the average individual predicted Ceq was 9.4 +/- 3.8 mmol/L, with absolute individual prediction error of 6.2% +/- 4.4%. For a given dialysis goal and desired dialysis duration, the required blood flow rate and dialyzer size are predicted by IBKM and confirmed by the analysis data. This study suggests that the IBKM can be used in a pediatric HD setting and accurately predict Ceq in children using only pre-HD and immediately post-HD BUN. PMID:20168209

Marsenic, Olivera; Zhang, Liping; Zuppa, Athena; Barrett, Jeffrey S; Pfister, Marc

2010-01-01

336

14C-urea breath test in C pylori gastritis.  

PubMed Central

14C-urea breath test was used to detect Campylobacter pylori colonisation in 129 consecutive non-ulcer dyspepsia patients. Fasting patients were given 3 microCi (110 kBq) of 14C-labelled urea after a test meal. Breath samples were collected at 10 minute intervals for 90 minutes and the C-14 activity was counted on a liquid scintillation analyser. Urea derived 14CO2 appears in the exhaled breath of Campylobacter pylori culture positive individuals within 20-30 minutes. Likelihood analysis revealed a most favourable cut off level of [0.07% dose 14C-urea/mmol CO2] multiplied by body weight at t = 40 minutes, to separate culture positive from culture negative subjects. Using this upper limit of normal, a positive likelihood ratio of 50 and a negative likelihood ratio of 0.05 was calculated. Sensitivity of the test was 95% and specificity 98%. The 14C-urea breath test is a simple, sensitive and non-invasive test, that detects viable C pylori microorganism and semiquantitatively assesses the bacterial load of C pylori colonisation. Administration of a single dose of colloidal bismuth subcitrate resulted in a rapid decrease in 14CO2 excretion, so this test can be used to confirm eradication of the bacterium in therapeutic trials without endoscopy, or need for culture. PMID:2753404

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

1989-01-01

337

Uric acid induces NADPH oxidase-independent neutrophil extracellular trap formation.  

PubMed

Neutrophil extracellular traps (NETs) are composed of extracellular DNA fibers with antimicrobial peptides that capture and kill microbes. NETs play a critical role in innate host defense and in autoimmune and inflammatory diseases. While the mechanism of NET formation remains unclear, reactive oxygen species (ROS) produced via activation of NADPH oxidase (Nox) are known to be an important requirement. In this study, we investigated the effect of uric acid (UA) on NET formation. UA, a well-known ROS scavenger, was found to suppress Nox-dependent ROS release in a dose-dependent manner. Low concentrations of UA significantly inhibited Nox-dependent NET formation. However, high concentrations of UA unexpectedly induced, rather than inhibited, NET formation. NETs were directly induced by UA alone in a Nox-independent manner, as revealed by experiments using control neutrophils treated with ROS inhibitors or neutrophils of patients with chronic granulomatous disease who have a congenital defect in ROS production. Furthermore, we found that UA-induced NET formation was partially mediated by NF-?B activation. Our study is the first to demonstrate the novel function of UA in NET formation and may provide insight into the management of patients with hyperuricemia. PMID:24326071

Arai, Yasuyuki; Nishinaka, Yoko; Arai, Toshiyuki; Morita, Makiko; Mizugishi, Kiyomi; Adachi, Souichi; Takaori-Kondo, Akifumi; Watanabe, Tomohiro; Yamashita, Kouhei

2014-01-10

338

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

PubMed Central

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

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

2013-01-01

339

Nano-sized platinum as a mimic of uricase catalyzing the oxidative degradation of uric acid.  

PubMed

Uric acid (UA) deposition in human body is very harmful, since it may induce gout. Therefore, it would be of great significance to catalyze the degradation of UA in human body. Herein, platinum nanoparticles (PtNPs) were found to be an effective mimic of uricase in the oxidation of UA. PtNPs could lower the activation energy of UA oxidation (i.e., from 139.49 kJ mol(-1) to 61.73 kJ mol(-1)), and thus increase the reaction rate constant dramatically (e.g., by the catalysis of 2.63 mg L(-1) PtNPs, the reaction rate constant of UA degradation at 37 °C was 5.85 × 10(-4) s(-1), which was almost 29000 times higher than that of without PtNPs (2.02 × 10(-8) s(-1))). Effects of degradation conditions, such as the concentration and size of PtNPs, concentration of dissolved oxygen and pH value of the solution on the catalytic degradation of UA have been studied. Furthermore, products of UA degradation were analyzed by GC-MS spectroscopy and FT-IR spectrometry. On this basis, a detailed mechanism was finally proposed for the PtNPs-catalyzed UA degradation. PMID:21359394

Dong, Yongqiang; Chi, Yuwu; Lin, Xiaomei; Zheng, Liyan; Chen, Lichan; Chen, Guonan

2011-04-01

340

Characterisation of Genome-Wide Association Epistasis Signals for Serum Uric Acid in Human Population Isolates  

PubMed Central

Genome-wide association (GWA) studies have identified a number of loci underlying variation in human serum uric acid (SUA) levels with the SLC2A9 gene having the largest effect identified so far. Gene-gene interactions (epistasis) are largely unexplored in these GWA studies. We performed a full pair-wise genome scan in the Italian MICROS population (n?=?1201) to characterise epistasis signals in SUA levels. In the resultant epistasis profile, no SNP pairs reached the Bonferroni adjusted threshold for the pair-wise genome-wide significance. However, SLC2A9 was found interacting with multiple loci across the genome, with NFIA - SLC2A9 and SLC2A9 - ESRRAP2 being significant based on a threshold derived for interactions between GWA significant SNPs and the genome and jointly explaining 8.0% of the phenotypic variance in SUA levels (3.4% by interaction components). Epistasis signal replication in a CROATIAN population (n?=?1772) was limited at the SNP level but improved dramatically at the gene ontology level. In addition, gene ontology terms enriched by the epistasis signals in each population support links between SUA levels and neurological disorders. We conclude that GWA epistasis analysis is useful despite relatively low power in small isolated populations. PMID:21886828

Wei, Wenhua; Hemani, Gibran; Hicks, Andrew A.; Vitart, Veronique; Cabrera-Cardenas, Claudia; Navarro, Pau; Huffman, Jennifer; Hayward, Caroline; Knott, Sara A.; Rudan, Igor; Pramstaller, Peter P.; Wild, Sarah H.; Wilson, James F.; Campbell, Harry; Dunlop, Malcolm G.; Hastie, Nicholas; Wright, Alan F.; Haley, Chris S.

2011-01-01

341

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

PubMed Central

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

Kim, Tae-Hyoung; Lee, Jae-Hyeok

2014-01-01

342

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

PubMed

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

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

2014-03-15

343

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

PubMed

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

Scope, Alexandra; Schwendenwein, Ilse; Schauberger, Günther

2013-09-01

344

Application and evaluation of a new cold-stable kinetic Jaffé reagent to the Hitachi 747 for the determination of serum creatinine  

Microsoft Academic Search

One of the most commonly requested tests of the clinical laboratory is that of serum creatinine. Since the late 19th century the most commonly used reagents have been those based upon the work of Jaffé [1], which are composed of alkali and picric acid. Upon addition of creatinine to this reagent a red color, referred to as a Janovsky complex

Joseph D. Artiss; Raymond E. Karcher; Sandra L. Collins; Bennie Zak

2000-01-01

345

Influences of dietary sucrose and urea on transfer of endogenous urea to the rumen of sheep and numbers of epithelial bacteria.  

PubMed

1. The rates of transfer of plasma urea to the rumen of six sheep given brome grass (Bromus inermis) pellets alone or with supplements of sucrose or urea were determined using [14C] urea and 14C-labelled sodium bicarbonate infusions during three periods. 2. The sheep were slaughtered after the third period and samples of rumen epithelium were taken for assessment of numbers of adherent bacteria. 3. Maximum transfer (0.31 g nitrogen/h) of urea ot the rumen was observed for sheep given supplements of 150 g sucrose/d plus 20 g urea/d. Maximum clearance of plasma urea to the rumen (rate of urea transfer to the rumen per unit plasma urea concentration, 5.8 1/h) was observed for sheep given 300 g sucrose/d. 4. Urea clearance to the rumen was negatively related to rumen ammonia concentration; the slope of the relationship was increased with each addition of sucrose to the diet. 5. Numbers of facultative bacteria adherent to the rumen epithelium were increased by urea and sucrose supplements. 6. The results are discussed in relation to a hypothesis which relates the ureolytic capability of the bacteria adherent to the rumen epithelium to the control of the rate of transfer of urea into the rumen. PMID:7317347

Kennedy, P M; Clarke, R T; Milligan, L P

1981-11-01

346

Role for urea in nitrification by polar marine Archaea  

PubMed Central

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

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

2012-01-01

347

Role for urea in nitrification by polar marine Archaea.  

PubMed

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

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

2012-10-30

348

Serum creatinine level, a surrogate of muscle mass, predicts mortality in peritoneal dialysis patients  

PubMed Central

Background In hemodialysis patients, higher serum creatinine (Cr) concentration represents larger muscle mass and predicts greater survival. However, this association remains uncertain in peritoneal dialysis (PD) patients. Methods In a cohort of 10 896 PD patients enrolled from 1 July 2001 to 30 June 2006, the association of baseline serum Cr level and change during the first 3 months after enrollment with all-cause mortality was examined. Results The cohort mean ± SD age was 55 ± 15 years old and included 52% women, 24% African-Americans and 48% diabetics. Compared with patients with serum Cr levels of 8.0–9.9 mg/dL, patients with serum Cr levels of <4.0 mg/dL and 4.0–5.9 mg/dL had higher risks of death {HR 1.36 [95% confidence interval (95% CI) 1.19–1.55] and 1.19 (1.08–1.31), respectively} whereas patients with serum Cr levels of 10.0–11.9 mg/dL, 12.0–13.9 mg/dL and ?14.0 mg/dL had lower risks of death (HR 0.88 [95% CI 0.79–0.97], 0.71 [0.62–0.81] and 0.64 [0.55–0.75], respectively) in the fully adjusted model. Decrease in serum Cr level over 1.0 mg/dL during the 3 months predicted an increased risk of death additionally. The serum Cr–mortality association was robust in patients with PD treatment duration of ?12 months, but was not observed in those with PD duration of <3 months. Conclusions Muscle mass reflected in serum Cr level may be associated with survival even in PD patients. However, the serum Cr–mortality association is attenuated in the early period of PD treatment, suggesting competing effect of muscle mass versus residual renal function on mortality. PMID:23743018

Park, Jongha; Mehrotra, Rajnish; Rhee, Connie M.; Molnar, Miklos Z.; Lukowsky, Lilia R.; Patel, Sapna S.; Nissenson, Allen R.; Kopple, Joel D.; Kovesdy, Csaba P.; Kalantar-Zadeh, Kamyar

2013-01-01

349

Reference Intervals of Total Bilirubin, ALT, AST, and Creatinine in Healthy Elderly Chinese  

PubMed Central

Background The aim of this study was to establish the reference intervals (RIs) of total bilirubin (TBIL), alanine aminotransferase (ALT), aspartate transaminase (AST), and creatinine (CREA) for apparently healthy elderly (Han ethnicity) in Shuyang, China. Material/Methods A total of 54 912 blood specimens from elderly residents age 65–104 years were collected by standard procedures in Shuyang county of Jiangsu province. TBIL, ALT, AST, and CREA for each participant were determined by automatic biochemical analyzer. Distribution and differences of TBIL, ALT, AST, and CREA were analyzed and compared between the elderly of the same age of different sexes and different ages of the same sex. RIs of TBIL, ALT, AST, and CREA were compared with the current RIs. The RIs and 95% confidence intervals were calculated using nonparametric method (2.5th–97.5th percentiles) according to the guideline of the Clinical and Laboratory Standards Institute. Results RIs established for the healthy elderly include: TBIL 7.8~30.6 ?mol/L for males and 7.3~26.1 ?mol/L for females; ALT 8.7~47.3 U/L for males and 8.4~45.2 U/L for females; AST 15.7~46.9 U/L for males and 15.1~46.2 U/L for females; and CREA 45.1~100.9 ?mol/L for males and 38.7~85.0 ?mol/L for females. Reference intervals of TBIL, ALT, AST, and CREA for male elderly were higher than those of females, and values of CREA increased with increasing age. Conclusions We have established a panel of locally relevant RIs. It is necessary to establish scientific and reasonable RIs of TBIL, ALT, AST, and CREA for the healthy elderly in our region, which will provide a reference for clinicians and inspection officers. PMID:25272068

Zhang, Guo-ming; Xia, Yong-jie; Guo, Xu-xiao; Zhu, Bao-lin; Zhang, Gao-ming; Ma, Xiao-bo; Yu, Hong; Wang, Hong-jian; Wang, Guang-sheng; Yang, Li; Zhou, Ye-ting

2014-01-01

350

Large amplitude vibrations of Urea in gas phase  

NASA Astrophysics Data System (ADS)

Large amplitude motions of isolated Urea are analyzed using CCSD(T) calculations. Urea shows two conformers of C s and C 2 symmetries that interconvert through the NH 2 torsion and the NH 2 inversion motions. Anharmonic frequencies are computed using second order perturbation theory and an ab initio force field. The potential energy surface shows 16 minima. Nine stationary points are determined. Five reduced Hamiltonians are used for the vibrational energy determination, concluding that at least a variational treatment based on a 4D model is required for the FIR spectrum simulation. The inversion barrier produces a large splitting of the vibrational ground state.

Inostroza, N.; Senent, M. L.

2012-02-01

351

Bis(acetato-?O)bis-(thio-urea-?S)cobalt(II)  

PubMed Central

The title compound, [Co(CH3COO)2(CH4N2S)2], is isotypic with the corresponding ZnII complex. The metal atom is in a distorted tetra­hedral coordination environment with the two S atoms from two thio­urea ligands and two O atoms from two acetate anions as the coordinating atoms. All H atoms of the thio­urea ligands are involved in N—H?O and N—H?S hydrogen bonds, leading to a three-dimensional network. PMID:24764944

Lutz, Martin

2014-01-01

352

2-Methyl-pyridine-urea (1/1)  

PubMed Central

In the crystal structure of the title compound, C6H7N·CH4N2O, the 2-methyl­pyridine and urea mol­ecules are linked via N—H?O and N—H?N hydrogen bonds, forming ribbons extending along the a axis. The dihedral angle between the 2-methyl­pyridine and urea mean planes is 89.09?(9)°. The methyl group shows rotational disorder wherein the H atoms are located over two sets of sites with equal occupancies. PMID:22347105

Ashurov, Jamshid; Ibragimov, Bakhtiyar; Talipov, Samat

2012-01-01

353

The Action of Certain Acid Reagents on the Substituted Ureas  

E-print Network

and METHYL PHENYL UREA CHLORIDE with PYRIDINE. Ph Ph-N -Me Ph-N~Et >-H + >>-0 4 C.H.N — > >C^0 4-C5H5N^HC1 Et Cl^ Ph-N-Me Molecular quantities of the original materials were heated in an oil bath for a short time (30 min.) at 140°C. The pyridine... and methyl phenyl urea chloride. It was obtained in a pure state by recrystallization from gasoline and melted at 104°C. which was the melting point C~0 C5H5N > When molecular quantities of each compound were mixed in a lagge test tube and heated...

Brewster, Ray Q.

1915-01-01

354

Nonaaqua­praseodymium triiodide–thio­urea (1/2)  

PubMed Central

The title compound, [Pr(H2O)9]I3·2CS(NH2)2, an adduct of nona­aqua­praseodymium triiodide with two thio­urea mol­ecules, is composed from [Pr(H2O)9]3+ cations (polyhedron: monocapped tetra­gonal anti­prism), noncoordinated thio­urea mol­ecules and iodide anions. The components are evidently connected by hydrogen bonds but in the presence of heavy atoms water H atoms have not been located. The complex cation and one of the two independent iodide anions are located on a twofold axis. PMID:22346801

Antonenko, Taisia A.; Alikberova, Lyudmila Yu.; Albov, Dmitry V.

2012-01-01

355

Urea is a dynamic pool of bioavailable nitrogen in coral reefs  

NASA Astrophysics Data System (ADS)

Urea may be an important source of nitrogen in low nutrient coral reef environments because corals and other organisms can assimilate it easily and it is found throughout ocean waters. We measured the distribution and concentrations of urea in seagrass beds, areas of schooling fish, coral formations and bottom sediments in the Upper Florida Keys Reef Tract. The flux of urea from bottom sediments was also measured. Ambient concentrations of urea in the offshore reefs were similar to the concentrations of nitrate and ammonium. Seagrass beds, areas of schooling fish and coral formations had elevated concentrations of urea that were up to eight times higher than nitrate in the system. Numerous ephemeral hotspots of urea that were 8-20 times the ambient urea concentration existed in seagrass beds, areas of schooling fish, and above sediments. Coastal areas and inland canals had high urea concentrations where urban runoff and septic effluents were prevalent, but there was no anthropogenic influence in the offshore habitats. Urea concentrations above bottom sediments were not different from ambient concentrations and benthic flux chamber incubations showed biological activity in carbonaceous sediments but no net urea production. The decrease in urea concentrations from coasts and inland waterways to a consistent ambient concentration in the offshore reef system and ephemeral hotspots of high urea concentration suggest that urea is a dynamic pool of bioavailable nitrogen in the reefs of the Upper Florida Keys.

Crandall, J. B.; Teece, M. A.

2012-03-01

356

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

357

Multicommutation in flow analysis. Part 3. Spectrophotometric kinetic determination of creatinine in urine exploiting a novel zone sampling approach  

Microsoft Academic Search

Zone sampling performed on a single analytical channel and associated with the stopped-flow approach was proposed and applied to the spectrophotometric kinetic determination of creatinine in urine based on Jaffé's reaction. The flow network comprised microcomputer controlled three-way solenoid valves. With multicommutation, the potentialities of zone sampling and stopped-flow were expanded, and the design of the flow set up was

Alberto N. Araújo; José L. F. Costa Lima; Boaventura F. Reis; Elias A. G. Zagatto

1995-01-01

358

Prediction of 24-hour protein excretion in pregnancy with a single voided urine protein-to-creatinine ratio  

Microsoft Academic Search

Objective: This study was undertaken to validate the prediction of 24- hour urine protein excretion by a single voided urine protein-to-creatinine (P:C) ratio in a hospitalized pregnant population at our institution. We sought to evaluate the ability of serial single voided P:C ratios to follow the course of proteinuria. Study Design: Pregnant patients who were admitted to the antepartum unit

Adrienne B. Neithardt; Sharon L. Dooley; Jayme Borensztajn

2002-01-01

359

Simultaneous determination of dopamine, ascorbic acid, and uric acid using carbon ionic liquid electrode.  

PubMed

A recently constructed carbon composite electrode using room temperature ionic liquid as pasting binder was employed as a novel electrode for sensitive, simultaneous determination of dopamine (DA), ascorbic acid (AA), and uric acid (UA). The apparent reversibility and kinetics of the electrochemical reaction for DA, AA, and UA found were improved significantly compared to those obtained using a conventional carbon paste electrode. The results show that carbon ionic liquid electrode (CILE) reduces the overpotential of DA, AA, and UA oxidation, without showing any fouling effect due to the deposition of their oxidized products. In the case of DA, the oxidation and reduction peak potentials appear at 210 and 135mV (vs Ag/AgCl, KCl, 3.0M), respectively, and the CILE shows a significantly better reversibility for dopamine. The oxidation peak due to the oxidation of AA occurs at about 60mV. For UA, a sharp oxidation peak at 340mV and a small reduction peak at 250mV are obtained at CILE. Differential pulse voltammetry was used for the simultaneous determination of ternary mixtures of DA, AA, and UA. Relative standard deviation for DA, AA, and UA determinations were less than 3.0% and DA, AA, and UA can be determined in the ranges of 2.0x10(-6)-1.5x10(-3), 5.0x10(-5)-7.4x10(-3), and 2.0x10(-6)-2.2x10(-4)M, respectively. The method was applied to the determination of DA, AA, and UA in human blood serum and urine samples. PMID:17069745

Safavi, Afsaneh; Maleki, Norouz; Moradlou, Omran; Tajabadi, Fariba

2006-12-15

360

False in vitro and in vivo elevations of uric acid levels in mouse blood.  

PubMed

Uric acid (UA) levels in mouse blood have been reported to range widely from 0.1 ?M to 760 ?M. The aim of this study was to demonstrate false in vitro and in vivo elevations of UA levels in mouse blood. Male ICR mice were anesthetized with pentobarbital (breathing mice) or sacrificed with overdose ether (non-breathing mice). Collected blood was dispensed into MiniCollect® tubes and incubated in vitro for 0 or 30 min at room temperature. After separation of plasma or serum, the levels of UA and hypoxanthine were determined using HPLC. From the non-incubated plasma of breathing mice, the true value of UA level in vivo was 13.5±1.4 ?M. However, UA levels in mouse blood increased by a factor of 3.9 following incubation in vitro. This "false in vitro elevation" of UA levels in mouse blood after blood sampling was inhibited by allopurinol, a xanthine oxidase inhibitor. Xanthine oxidase was converted to UA in mouse serum from hypoxanthine which was released from blood cells during incubation. Plasma UA levels from non-breathing mice were 19 times higher than those from breathing mice. This "false in vivo elevation" of UA levels before blood sampling was inhibited by pre-treatment with phentolamine, an ?-antagonist. Over-anesthesia with ether might induce ?-vasoconstriction and ischemia and thus degrade intracellular ATP to UA. For the accurate measurement of UA levels in mouse blood, the false in vitro and in vivo elevations of UA level must be avoided by immediate separation of plasma after blood sampling from anesthetized breathing mice. PMID:24940669

Watanabe, Tamaki; Tomioka, Naoko H; Watanabe, Shigekazu; Tsuchiya, Masao; Hosoyamada, Makoto

2014-01-01

361

Serum Uric Acid and 1-h Postload Glucose in Essential Hypertension  

PubMed Central

OBJECTIVE Subjects who are normal glucose tolerant (NGT) are considered at low risk, even if a plasma glucose value ?155 mg/dL for the 1-h postload plasma glucose during an oral glucose tolerance test (OGTT) is able to identify NGT subjects at high risk for type 2 diabetes and subclinical organ damage. Hyperuricemia is associated with several risk factors for cardiovascular diseases such as hypertension, insulin resistance, and diabetes. However, it is unknown whether uric acid (UA) is able to affect 1-h postload plasma glucose in hypertensive NGT subjects. RESEARCH DESIGN AND METHODS From a cohort of ?1,200 uncomplicated hypertensive outpatients who underwent OGTT, we selected 955 subjects (548 men and 407 women) aged 45.6 ± 10.1 years. Laboratory evaluations were performed, and estimated glomerular filtration rate was assessed by using the new equation proposed by investigators in the Chronic Kidney Disease Epidemiology Collaboration. RESULTS Considering different stepwise multivariate linear regression models, UA was the major predictor of 1-h postload glucose in the entire population, with NGT ?155 subjects, impaired glucose tolerant, and type 2 diabetic patients accounting for 26.0% (P < 0.0001), 25.3% (P < 0.0001), 13.5% (P < 0.0001), and 13.5% (P = 0.003) of its variation in the respective models. CONCLUSIONS We documented that in hypertensive NGT ?155 subjects, UA is strongly associated with 1-h postload glucose, similarly to what is observed in impaired glucose tolerant and diabetic patients. PMID:22011411

Perticone, Francesco; Sciacqua, Angela; Perticone, Maria; Arturi, Franco; Scarpino, Paola Elisa; Quero, Michele; Sesti, Giorgio

2012-01-01

362

ABCG2 dysfunction increases serum uric acid by decreased intestinal urate excretion.  

PubMed

ATP-binding cassette transporter G2 (ABCG2), also known as breast cancer resistance protein (BCRP), is identified as a high-capacity urate exporter and its dysfunction has an association with serum uric acid (SUA) levels and gout/hyperuricemia risk. However, pathophysiologically important pathway(s) responsible for the ABCG2-mediated urate excretion were unknown. In this study, we investigated how ABCG2 dysfunction affected the urate excretion pathways. First, we revealed that mouse Abcg2 mediates urate transport using the membrane vesicle system. The export process by mouse Abcg2 was ATP-dependent and not saturable under the physiological concentration of urate. Then, we characterized the excretion of urate into urine, bile, and intestinal lumen using in vivo mouse model. SUA of Abcg2-knockout mice was significantly higher than that of control mice. Under this condition, the renal urate excretion was increased in Abcg2-knockout mice, whereas the urate excretion from the intestine was decreased to less than a half. Biliary urate excretion showed no significant difference regardless of Abcg2 genotype. From these results, we estimated the relative contribution of each pathway to total urate excretion; in wild-type mice, the renal excretion pathway contributes approximately two-thirds, the intestinal excretion pathway contributes one-third of the total urate excretion, and the urate excretion into bile is minor. Decreased intestinal excretion could account for the increased SUA of Abcg2-knockout mice. Thus, ABCG2 is suggested to have an important role in extra-renal urate excretion, especially in intestinal excretion. Accordingly, increased SUA in patients with ABCG2 dysfunction could be explained by the decreased excretion of urate from the intestine. PMID:24940679

Takada, Tappei; Ichida, Kimiyoshi; Matsuo, Hirotaka; Nakayama, Akiyoshi; Murakami, Keizo; Yamanashi, Yoshihide; Kasuga, Hiroshi; Shinomiya, Nariyoshi; Suzuki, Hiroshi

2014-01-01

363

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

PubMed Central

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

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

2014-01-01

364

The relationship between uric acid and erectile dysfunction in hypertensive subjects.  

PubMed

Abstract Background. Endothelial dysfunction plays a major role in erectile dysfunction (ED). Uric acid (UA) is a marker of endothelial dysfunction. We hypothesized that increased UA levels may be associated with ED and aimed to investigate whether there is a relationship between, UA and ED in hypertensive patients. Methods. A total of 200 hypertensive patients who have a normal treadmill exercise test were divided into two groups based on the Sexual Health Inventory for Men (SHIM) test (< 21 defined as ED n = 110, and ? 21 defined as normal erectile function n = 90). The differences between the ED and normal erectile function groups were compared and determinants of ED were analyzed. Main results. The prevalence of ED was found to be 55.0%. Office blood pressure level was comparable between groups. UA levels were significantly increased in the ED group (6.20 ± 1.56 vs 5.44 ± 1.32, p = 0.01). In a regression model, age [odds ratio (95% confidence interval): 1.08 (1.04-1.14), p = 0.001], smoking [odds ratio: 2.33 (1.04-5.20), p = 0.04] and UA [odds ratio: 1.76 (1.28-2.41), p = 0.04] were independent determinants of ED. An UA level of > 5.2 mg/dl had 76.2% sensitivity, 43.7% specificity, 62.9% positive and 59.4% negative predictive value for determining ED. Conclusion. UA is an independent determinant of ED irrespective of blood pressure control and questioning erectile function for hypertensive patients with increased UA levels may be recommended. PMID:25029530

Aribas, Alpay; Kayrak, Mehmet; Ulucan, Seref; Keser, Ahmet; Demir, Kenan; Alibasic, Hayrudin; Akilli, Hakan; Solak, Yalcin; Avci, Ahmet; Turan, Yasar; Kaya, Zeynettin; Katlandur, Huseyin; Kanbay, Mehmet

2014-12-01

365

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

PubMed Central

Introduction Recent evidence suggests that uric acid (UA), regardless of crystal deposition, may play a direct pathogenic role in renal disease. We have shown that UA is an independent predictor of hypertension and cardiovascular disease (CVD), and that CVD risk factors associate with renal dysfunction, in patients with rheumatoid arthritis (RA). In this study we investigated whether UA associates with renal dysfunction in patients with RA and whether such an association is independent or mediated through other comorbidities or risk factors for renal impairment. Methods Renal function was assessed in 350 consecutive RA patients by estimated glomerular filtration rate (GFR) using the six-variable Modification of Diet in Renal Disease equation. Risk factors for renal dysfunction were recorded or measured in all participants. Linear regression was used to test the independence of the association between GFR and UA. Results Univariable analysis revealed significant associations between GFR and age, systolic blood pressure, total cholesterol, triglycerides, RA duration and UA. UA had the most powerful association with renal dysfunction (r = -0.45, P < 0.001). A basic model was created, incorporating all of the above parameters along with body mass index and gender. UA ranked as the first correlate of GFR (P < 0.001) followed by age. Adjustments for the use of medications (diuretics, low-dose aspirin, cyclooxygenase II inhibitors and nonsteroidal anti-inflammatory drugs) and further adjustment for markers of inflammation and insulin resistance did not change the results. Conclusions UA is a strong correlate of renal dysfunction in RA patients. Further studies are needed to address the exact causes and clinical implications of this new finding. RA patients with elevated UA may require screening for renal dysfunction and appropriate management. PMID:19630964

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

2009-01-01

366

Effect of plasma uric acid on antioxidant capacity, oxidative stress, and insulin sensitivity in obese subjects.  

PubMed

Oxidative stress is purported to be involved in the pathogenesis of obesity-associated insulin resistance. We evaluated whether alterations in levels of circulating uric acid (UA), a systemic antioxidant, affects the following: 1) systemic (plasma and saliva) nonenzymatic antioxidant capacity (NEAC); 2) markers of systemic (urinary 8-iso-prostaglandin-F2?) and muscle (carbonylated protein content) oxidative stress; and 3) whole-body insulin sensitivity (percentage increase in glucose uptake during a hyperinsulinemic-euglycemic clamp procedure). Thirty-one obese subjects (BMI 37.1 ± 0.7 kg/m(2)) with either high serum UA (HUA; 7.1 ± 0.4 mg/dL; n = 15) or normal serum UA (NUA; 4.5 ± 0.2 mg/dL; n = 16) levels were studied; 13 subjects with HUA levels were studied again after reduction of serum UA levels to 0 by infusing a recombinant urate oxidase. HUA subjects had 20-90% greater NEAC, but lower insulin sensitivity (40%) and levels of markers of oxidative stress (30%) than subjects in the NUA group (all P < 0.05). Acute UA reduction caused a 45-95% decrease in NEAC and a 25-40% increase in levels of systemic and muscle markers of oxidative stress (all P < 0.05), but did not affect insulin sensitivity (from 168 ± 25% to 156 ± 17%, P = NS). These results demonstrate that circulating UA is a major antioxidant and might help protect against free-radical oxidative damage. However, oxidative stress is not a major determinant of insulin action in vivo. PMID:24353177

Fabbrini, Elisa; Serafini, Mauro; Colic Baric, Irena; Hazen, Stanley L; Klein, Samuel

2014-03-01

367

Serum Uric Acid Levels in Patients with Alzheimer's Disease: A Meta-Analysis  

PubMed Central

Background Serum uric acid (UA) could exert neuro-protective effects against Alzheimer's disease (AD) via its antioxidant capacities. Many studies investigated serum UA levels in AD patients, but to date, results from these observational studies are conflicting. Methods We conducted a meta-analysis to compare serum UA levels between AD patients and healthy controls by the random-effects model. Studies were identified by searching PubMed, ISI Web of Science, EMBASE, and the Cochrane library databases from 1966 through July 2013 using the Medical Subject Headings and keywords without restriction in languages. Only case-control studies were included if they had data on serum UA levels in AD patients and healthy controls. Begg's funnel plot and Egger's regression test were applied to assess the potential publication bias. Sensitivity analyses and meta-regression were conducted to explore possible explanations for heterogeneity. Results A total of 11 studies met the inclusion criteria including 2708 participants were abstracted. Serum UA levels were not significantly different in AD patients compared to healthy controls (standardized mean difference (SMD)?=??0.50; 95% confidence interval (CI): ?1.23 to 0.22). Little evidence of publication bias was observed. Sensitivity analyses showed that the combined SMD was consistent every time omitting any one study, except only one study which greatly influenced the overall results. Meta-regression showed that year of publication, race, sample size, and mean age were not significant sources of heterogeneity. Conclusion Our meta-analysis of case-control studies suggests that serum UA levels do not differ significantly in AD patients, but there may be a trend toward decreased UA in AD after an appropriate interpretation. More well-designed investigations are needed to demonstrate the potential change of serum UA levels in AD patients. PMID:24714617

Chen, Xueping; Guo, Xiaoyan; Huang, Rui; Chen, Yongping; Zheng, Zhenzhen; Shang, Huifang

2014-01-01

368

Effects of dopexamine on creatinine clearance, systemic inflammation, and splanchnic oxygenation in patients undergoing coronary artery bypass grafting.  

PubMed

Impairment of splanchnic and peripheral tissue perfusion during cardiopulmonary bypass (CPB) may be responsible for endotoxin-mediated systemic inflammation and acute phase responses. We examined the effects of dopexamine on hemodynamic parameters, creatinine clearance, systemic and splanchnic oxygenation, gastric mucosal pH (pHi), and mixed and hepatic venous plasma levels of endotoxin, interleukin-6 (IL-6), serum amyloid A (SAA), and C-reactive protein (CRP) in 44 patients scheduled for coronary artery bypass grafting. Patients were randomized to receive continuous infusions of 0.5, 1.0, or 2 micrograms.kg-1.min-1 dopexamine (n = 10 per group) or placebo (n = 14) prior to surgery, intraoperatively, and postoperatively. Dopexamine infusion increased systemic oxygen delivery (P < or = 0.01). Hepatic venous oxygen saturation did not change, and pHi decreased during and after CPB in all patients (P < or = 0.01). Postoperative increases in IL-6 were smallest in patients who received 2.0 micrograms.kg-1.min-1 dopexamine (P < or = 0.02). SAA and CRP increases during the postoperative period were less pronounced with dopexamine throughout the study. Creatinine clearance was elevated in all dopexamine groups (P < or = 0.025). This elevation was higher with lower dopexamine doses (P < or = 0.025). We conclude that dopexamine improves creatinine clearance and reduces systemic inflammation without affecting splanchnic oxygenation. PMID:9141914

Berendes, E; Möllhoff, T; Van Aken, H; Schmidt, C; Erren, M; Deng, M C; Weyand, M; Loick, H M

1997-05-01

369

Comparison of instrument-read dipsticks for albumin and creatinine in urine with visual results and quantitative methods.  

PubMed

Three hospital sites evaluated the Bayer two-pad urine dipstick as a screening test for microalbuminuria. One pad estimates albumin concentrations between 10 and 150 mg/L, and the second estimates creatinine values between 300 and 3,000 mg/L. The Boehringer Mannheim (BMD) Micral dipstick was also compared and evaluated. The accuracy of the dipsticks was judged by comparison with cuvet-based immunonephelometry for albumin and to standard rate-Jaffe methods for creatinine; these assays were well standardized and controlled and were assumed to give accurate values. Precision of these methods and that of the dipsticks was determined by multiple assays of control materials. Visual or instrument (Clinitek 50 or 100) evaluation of the Bayer or visual checks of the BMD albumin dipstick pad with patients' urines gave clinically acceptable accuracy. The albumin/creatinine ratio from the Bayer dipsticks gave better accuracy for albumin excretion than the albumin pads alone from either manufacturer. This ratio should permit making a good estimate of the 24-hr albumin excretion in a randomly collected urine. PMID:9773958

Pugia, M J; Lott, J A; Luke, K E; Shihabi, Z K; Wians, F H; Phillips, L

1998-01-01

370

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

371

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

372

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

Federal Register 2010, 2011, 2012, 2013

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

2012-07-18

373

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

Federal Register 2010, 2011, 2012, 2013

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

2011-06-17

374

New urea-absorbing polymers for artificial kidney machines  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

375

Urea retention and uptake by avocado and apple leaves  

Microsoft Academic Search

Solution retention by avocado (Persea americana cv. Fuerte) and apple (Mallus domestica Burkh. cv. Anna) leaves was measured by weight gain of detached leaves after dipping them in solutions of two surfactants and by analysis of various concentrations of urea retained at zero time on surfaces of attached leaves. Linear regression equations were calulated, relating leaf area and retention of

Isaac Klein; Shmuel Zilkah

1986-01-01

376

Seasonal Variation and Response to Osmotic Challenge in Urea  

E-print Network

employed to prevent excessive water loss. In hydrated amphib- ians, urea is usually maintained at low, with a low abundance prevailing in the fall and winter, and higher levels occurring in the spring. The latter is accomplished by reducing glomerular filtration rate (GFR), adjusting the secretion

Lee Jr., Richard E.

377

IRIS Toxicological Review of Urea (Interagency Science Consultation Draft)  

EPA Science Inventory

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

378

Tailoring of analytical performances of urea biosensors using nanomaterials  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

379

Use of Two Sulfonyl Urea Herbicides in Lowbush Blueberry  

Microsoft Academic Search

The continuous use of the broad spectrum herbicide hexazinone since 1981 has resulted in many changes to the weedy flora of lowbush blueberry fields, including shifts to hexazinone-tolerant species. Many of these occur in patches and could best be controlled by selective, foliar herbicide treatments. Preliminary assessments of several sufonyl urea (SU) herbicides indicated that tribenuron (Spartan or Express 75%

Klaus I. N. Jensen; Eric G. Specht

2004-01-01

380

Chiral ?-Iodoamines by Urea-Catalyzed Iodocyclization of Trichloroacetimidates  

PubMed Central

Highly enantioselective vicinal iodoamination of olefins is accomplished through the iodocyclization of alkenyl trichloroacetimidates catalyzed by a new chiral Schiff-base urea derivative. The resulting products are converted readily to a variety of polyfunctional amine-containing chiral building blocks. PMID:24416631

Brindle, Cheyenne S.; Yeung, Charles S.

2013-01-01

381

Leaching and transformation of urea in dry and wet soils as affected by irrigation water  

Microsoft Academic Search

Summary  The leaching losses of urea in dry and wet soils as affected by the irrigation water, were studied in 90 cm long and 5 cm\\u000a diameter plexiglass columns. In dry sandy loam soil urea leached with irrigation water and peaks of urea were observed with\\u000a water front but in sandy soil the wetting front moved faster leaving the urea peak

Mahendra Singh; D. S. Yadav; Vinod Kumar

1984-01-01

382

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

Microsoft Academic Search

Condensation of dimethylol urea and its mixtures with urea or hydrolysate of chrome-tanned leather waste (mass fraction in\\u000a mixture 0.05) in the presence of a variable quantity of phthalic acid, as acid curing agent (within mass fraction limits 0.01-0.1),\\u000a was studied through TG technique. During condensation of sole dimethylol urea or of its mixture with urea, oxy-methylene as\\u000a well as

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

2004-01-01

383

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

NASA Technical Reports Server (NTRS)

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

Wydeven, T.; Leban, M.

1973-01-01

384

Escalating Worldwide use of Urea – A Global Change Contributing to Coastal Eutrophication  

Microsoft Academic Search

While the global increase in the use of nitrogen-based fertilizers has been well recognized, another change in fertilizer\\u000a usage has simultaneously occurred: a shift toward urea-based products. Worldwide use of urea has increased more than 100-fold\\u000a in the past 4 decades and now constitutes >50% of global nitrogenous fertilizer usage. Global urea usage extends beyond agricultural\\u000a applications; urea is also

Patricia M. Glibert; John Harrison; Cynthia Heil; Sybil Seitzinger

2006-01-01

385

Antidiabetic effect of garlic ( Allium sativum L.) in normal and streptozotocin-induced diabetic rats  

Microsoft Academic Search

Objective: The antidiabetic effect of garlic ethanolic extract (Allium sativum L.) was investigated in normal and streptozotocin-induced diabetic rats.Research methods and procedure: In the present study, oral administration of garlic extract (0.1, 0.25 and 0.5g\\/kg body wt.) for 14 days on the level of serum glucose, total cholesterol, triglycerides, urea, uric acid, creatinine, aspartate amino transferase (AST) and alanine amino

A. Eidi; M. Eidi; E. Esmaeili

2006-01-01

386

A luminometer for determination of multiple metabolites in undiluted human plasma  

Microsoft Academic Search

A luminescence-based biosensor allowing for multiplex measurement of metabolites in undiluted human plasma is revealed in this study. Concurrent measurement of renal function-related metabolites including creatinine, urea, uric acid and glucose in a complex sample can be achieved in a single step using specially designed compositions which were pre-distributed into the analytical cartridge and freeze-dried into reagent-free powder. The dry-reagents

Hsiao-Chung Tsai; Su-Jan Leel; Tzu-l Wu; Erh-Fang Leel

2009-01-01

387

Effects of acute creatine supplementation on iron homeostasis and uric acid-based antioxidant capacity of plasma after wingate test  

PubMed Central

Background Dietary creatine has been largely used as an ergogenic aid to improve strength and athletic performance, especially in short-term and high energy-demanding anaerobic exercise. Recent findings have also suggested a possible antioxidant role for creatine in muscle tissues during exercise. Here we evaluate the effects of a 1-week regimen of 20?g/day creatine supplementation on the plasma antioxidant capacity, free and heme iron content, and uric acid and lipid peroxidation levels of young subjects (23.1?±?5.8?years old) immediately before and 5 and 60?min after the exhaustive Wingate test. Results Maximum anaerobic power was improved by acute creatine supplementation (10.5?%), but it was accompanied by a 2.4-fold increase in pro-oxidant free iron ions in the plasma. However, potential iron-driven oxidative insult was adequately counterbalanced by proportional increases in antioxidant ferric-reducing activity in plasma (FRAP), leading to unaltered lipid peroxidation levels. Interestingly, the FRAP index, found to be highly dependent on uric acid levels in the placebo group, also had an additional contribution from other circulating metabolites in creatine-fed subjects. Conclusions Our data suggest that acute creatine supplementation improved the anaerobic performance of athletes and limited short-term oxidative insults, since creatine-induced iron overload was efficiently circumvented by acquired FRAP capacity attributed to: overproduction of uric acid in energy-depleted muscles (as an end-product of purine metabolism and a powerful iron chelating agent) and inherent antioxidant activity of creatine. PMID:22691230

2012-01-01

388

8-Oxo-7,8-dihydroguanine and uric acid as efficient predictors of survival in colon cancer patients.  

PubMed

The aim of this work was to answer the question whether the broad range of parameters which describe oxidative stress and oxidatively damaged DNA and repair are appropriate prognosis factors of colon cancer (CRC) patients survival? The following parameters were analyzed for 89 CRC patients: concentration of uric acid and vitamins A, E, C in plasma; levels of 8-oxodGuo (8-oxo-7,8-dihydro-2'-deoxyguanosine) in DNA of leukocyte and colon tissues; urinary excretion rates of 8-oxodGuo and 8-oxoGua (8-oxo-7,8-dihydroguanine); the activity and mRNA or protein level of repair enzymes OGG1, APE1, ANPG, TDG and PARP1. All DNA modifications and plasma antioxidants were analyzed using high performance liquid chromatography (HPLC) or HPLC/gas chromatography-mass spectrometry techniques. Expression of repair proteins was analyzed by QPCR, Western or immunohistochemistry methods. Longer survival coincided with low levels of 8-oxodGuo/8oxoGua in urine and 8-oxodGuo in DNA as well as with high concentration of uric acid plasma level. In contrast to expectations, longer survival coincided with lower mRNA level in normal colon tissue of the main 8-oxoGua DNA glycosylase, OGG1, but no association was found for PARP-1 expression. When analyzing simultaneously two parameters the discriminating power increased significantly. Combination of low level of urinary 8-oxoGua together with low level of 8-oxodGuo in leukocyte (both below median value) or high concentration of plasma uric acid (above median value) have the best prediction power. Since prediction value of these parameters seems to be comparable to conventional staging procedure, they could possibly be used as markers to predict clinical success in CRC treatment. PMID:23832862

Dziaman, Tomasz; Banaszkiewicz, Zbigniew; Roszkowski, Krzysztof; Gackowski, Daniel; Wisniewska, Ewa; Rozalski, Rafa?; Foksinski, Marek; Siomek, Agnieszka; Speina, Elzbieta; Winczura, Alicja; Marszalek, Andrzej; Tudek, Barbara; Olinski, Ryszard

2014-01-15

389

Urea on Flaked Soybean Hulls as a Protein Replacement for Dairy Cows1  

Microsoft Academic Search

In Experiment I a Latin square design was used to study the utilization of urea nitrogen adsorbed on flaked soybean hulls in normal rations of high producing dairy cows. Concentrates containing urea, urea with supplemental minerals, or soybean meal as the protein supplement were fed with corn silage and alfalfa in a total ration of approximately 17% crude protein. Both

S. C. Peyton; H. R. Conrad

1978-01-01

390

Role of urea in the postprandial urine concentration cycle of the insectivorous bat Antrozous pallidus.  

PubMed

Insectivorous bats, which feed once daily, produce maximally concentrated urine only after feeding. The role of urea as an osmolyte in this process was investigated in pallid bats (Antrozous pallidus) in the laboratory. Following a 24-h fast, plasma and urine were sampled before and 2 h after feeding in postprandial (PP) animals and before and 2 h after similar treatment without feeding in nonfed (NF) animals. Food consumption by PP animals and handling of NF animals had no effect on blood water content as measured by hematocrit and plasma oncotic pressure. Food consumption increased both plasma osmolality (P(osm)) and plasma urea (P(urea)) by as much as 15%. Food consumption also increased urine osmolality (U(osm)) and urine urea (U(urea)) by 50-100%. Feeding increased U(osm) regardless of changes in P(osm), and elevation of U(osm) resulted primarily from increased U(urea). In NF bats, P(osm) and P(urea) were unchanged, while U(osm) and U(urea) increased by as much as 25%. Again, increased U(osm) resulted primarily from increased U(urea). The PP urine concentration cycle of pallid bats resulted from increased urea excretion in response to apparent rapid urea synthesis. Bats rapidly metabolized protein and excreted urea following feeding when body water was most plentiful. PMID:15123201

Bassett, John E

2004-02-01

391

Urea in the Tributaries of the Chesapeake and Coastal Bays of Maryland  

Microsoft Academic Search

Concentrations of dissolved urea were monitored in several Chesapeake Bay tributaries from 1998 to 2002. Urea is a commonly used agricultural fertilizer and is also a breakdown product of poultry manure, which is used as an additional source of fertilizer throughout the watershed. Two trends were apparent. First, in several of the tributaries, seasonal peaks in ambient urea concentration coincided

Patricia M. Glibert; T. Mark Trice; Bruce Michael

2005-01-01

392

ORIGINAL PAPER Osmotic and metabolic responses to dehydration and urea-loading  

E-print Network

ORIGINAL PAPER Osmotic and metabolic responses to dehydration and urea-loading in a dormant Abstract Physiological responses to dehydration in amphibians are reasonably well documented, although urea did not differ initially; however, upon dehydration, metabolic rates decreased sooner in the urea

Lee Jr., Richard E.

393

75 FR 51440 - Solid Urea from the Russian Federation: Final Results of Antidumping Duty Administrative Review  

Federal Register 2010, 2011, 2012, 2013

...solid urea from the Russian Federation. The...review was produced and exported by MCC...in the ``Issues and Decision Memorandum...Solid Urea from the Russian Federation for the...solid urea from the Russian Federation produced and exported by...

2010-08-20

394

Evidence for urea-induced hypometabolism in isolated organs of dormant ectotherms.  

PubMed

Many organisms endure extended periods of dormancy by depressing their metabolism, which effectively prolongs the use of their endogenous energy stores. Though the mechanisms of hypometabolism are varied and incompletely understood, recent work suggests that urea accumulation in autumn and early winter contributes to reduced metabolism of hibernating wood frogs (Rana sylvatica). Urea accumulation during dormancy is a widespread phenomenon, and it has long been presumed that numerous species from diverse taxa benefit from its hypometabolic effect. To investigate the phylogenetic prevalence of urea-induced hypometabolism, we studied four species of urea accumulators from the clades Amphibia (Spea bombifrons and Ambystoma tigrinum), Reptilia (Malaclemys terrapin), and Gastropoda (Anguispira alternata), and one amphibian species (R. pipiens) that does not accumulate urea during dormancy. We measured rates of oxygen consumption (VO(2)) of excised organ samples from dormant animals in the presence or absence of physiological concentrations of urea. Three of the four urea-accumulating species had at least one organ whose VO(2) was significantly decreased by urea treatment. However, VO(2) of organs from R. pipiens, the one species tested that does not accumulate urea during dormancy, was not affected by urea treatment. Our results support the hypothesis that urea accumulation can reduce metabolic rate of dormant animals and provide a base for further investigation into the evolution of urea-induced hypometabolism. PMID:19739087

Muir, Timothy J; Costanzo, Jon P; Lee, Richard E

2010-01-01

395

Effect of feeding baled and stacked urea treated rice straw on the performance of crossbred cows  

Microsoft Academic Search

Crossbred dairy cows (2–4 lactations) in three groups (4 in each group) were fed with rations containing (1) untreated rice straw ad libitum plus 1kg concentrate supplement, (2) urea treated (4% urea; 50% moisture) rice straw stored in stack for 14 days, and (3) urea treated paddy straw compressed as bales and stored for 14 days. Extra concentrate supplement was

R. D. D Prasad; M. R Reddy; G. V. N Reddy

1998-01-01

396

Influence of Crop Residues and Organic Manures on the Hydrolysis of Urea in a Typic Haplustept  

Microsoft Academic Search

The emphasis on integrated use of organic amendments and fertilizers has made it imperative to study the effect of crop residues and organic manures on urea hydrolysis, which governs the release of N from urea fertilizer. Urea hydrolysis in soils is an enzymatic decomposition process facilitated by the extracellular enzyme urease. Our aim was to assess the influence of crop

M. S. Mavi; Balwinder Singh

2007-01-01

397

Efficient voltammetric discrimination of free bilirubin from uric acid and ascorbic acid by a CVD nanographite-based microelectrode.  

PubMed

We report a novel electrochemical sensor based on nanographite grown on platinum microelectrodes for the determination of bilirubin in the presence of normal concentrations of albumin. The albumin is a protein with an intrinsic ability to bind the bilirubin therefore reducing the concentration of the free electroactive metabolite in human fluids. In addition, the proposed device permits the discrimination of free bilirubin from two interferents, uric acid and ascorbic acid, by the separation of their oxidation peaks in voltammetry. Preliminary measurements in human serum prove that the proposed nanostructured platform can be used to detect bilirubin. PMID:25159430

Taurino, Irene; Van Hoof, Viviane; Magrez, Arnaud; Forró, László; De Micheli, Giovanni; Carrara, Sandro

2014-12-01

398

Serum markers of chronic dehydration are associated with saliva spinability.  

PubMed

Findings of a relationship between saliva and dehydration have been observed, but the precise nature of these relationships is unclear and no evidence of a direct link has been found. In particular, no study reports a relationship between chronic dehydration and saliva conditions in community-dwelling older adults. This study aimed to identify whether salivary conditions are sensitive to body hydration markers in an elderly population. A total of 403 subjects aged 76 years participated in the study. Stimulated saliva flow rate and spinability of saliva were measured. In addition, determinations of serum levels of uric acid, blood urea nitrogen (BUN), creatinine, sodium and potassium were made. Dehydration was defined as uric acid >/= 7 mg dL(-1) according to the standard value. The salivary spinability were significantly associated with the concentration of uric acid (OR=2.06, P=0.044) according to multiple logistic regression analysis. In addition, after adjusting for gender, the uric acid concentration and the salivary spinability was significantly associated with BUN, potassium and creatinine levels. The subjects with high uric acid levels (>/= 7 mg dL(-1)) had the most elastic saliva. Both BUN and serum creatinine are the most commonly used indicators of renal function. Therefore, our findings might demonstrate that older adults who are dehydrated showed highly elastic saliva, which was associated with renal function. In conclusion, this study suggests that there is a significant relationship between chronic dehydration status and salivary spinability level. PMID:17824885

Yoshihara, A; Hirotomi, T; Takano, N; Kondo, T; Hanada, N; Miyazaki, H

2007-10-01

399

Effect of rates of nitrogen and relative efficiency of sulphur-coated urea and nitrapyrin-treated urea in dry matter production and nitrogen uptake by rice  

Microsoft Academic Search

Summary A field experiment conducted for two rainy seasons (1974 and 1975) on a sandy clay loam soil at the Indian Agricultural Research Institute, New Delhi showed that at 100kg N\\/ha the apparent recovery of urea nitrogen by the rice crop was only 28%, which was raised to 41.7% by treating urea with Nitrapyrin and to 47.4% by coating urea

S. N. Sharma; Rajendra Prasad

1980-01-01

400

Uric acid: A Danger Signal from the RNA World that may have a role in the Epidemic of Obesity, Metabolic Syndrome and CardioRenal Disease: Evolutionary Considerations  

PubMed Central

All humans are uricase knockouts; we lost the uricase gene due to a mutation that occurred in the mid Miocene approximately 15 million years ago. The consequence of being a uricase knockout is that we have higher serum uric acid levels that are less regulatable and can be readily influenced by diet. This increases our risk for gout and kidney stones, but there is also increasing evidence that uric acid increases our risk for hypertension, kidney disease, obesity and diabetes. This raises the question of why this mutation occurred. In this paper we review current hypotheses. We suggest that uric acid is a danger and survival signal carried over from the RNA world. The mutation of uricase that occurred during the food shortage and global cooling that occurred in the Miocene resulted in a survival advantage for early primates, particularly in Europe. Today, the loss of uricase functions as a thrifty gene, increasing our risk for obesity and cardiorenal disease. PMID:22000645

Johnson, Richard J; Lanaspa, Miguel A; Gaucher, Eric A

2011-01-01

401

Effects of treating rice straw with urea or urea and calcium hydroxide upon intake, digestibility, rumen fermentation and milk yield of dairy cows  

Microsoft Academic Search

Three, multiparous Holstein crossbred dairy cows with initial body weight of 385±19 kg were randomly allocated to 3 treatments of rice straw (T1 = untreated rice straw; T2 = 5.5% urea-treated rice straw (5 g urea in 100 ml water to 100 g air-dry (91% DM) straw); T3 = 2.2% urea+2.2% calcium hydroxide treated rice straw (2.0 g urea and 2.0 g Ca(OH)2 in 100 ml to

Metha Wanapat; Sineenart Polyorach; Kitsada Boonnop; Chaowarit Mapato; Anusorn Cherdthong

2009-01-01

402

Modelling and mutational analysis of Aspergillus nidulans UreA, a member of the subfamily of urea/H+ transporters in fungi and plants  

PubMed Central

We present the first account of the structure–function relationships of a protein of the subfamily of urea/H+ membrane transporters of fungi and plants, using Aspergillus nidulans UreA as a study model. Based on the crystal structures of the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT) and of the Nucleobase-Cation-Symport-1 benzylhydantoin transporter from Microbacterium liquefaciens (Mhp1), we constructed a three-dimensional model of UreA which, combined with site-directed and classical random mutagenesis, led to the identification of amino acids important for UreA function. Our approach allowed us to suggest roles for these residues in the binding, recognition and translocation of urea, and in the sorting of UreA to the membrane. Residues W82, Y106, A110, T133, N275, D286, Y388, Y437 and S446, located in transmembrane helixes 2, 3, 7 and 11, were found to be involved in the binding, recognition and/or translocation of urea and the sorting of UreA to the membrane. Y106, A110, T133 and Y437 seem to play a role in substrate selectivity, while S446 is necessary for proper sorting of UreA to the membrane. Other amino acids identified by random classical mutagenesis (G99, R141, A163, G168 and P639) may be important for the basic transporter's structure, its proper folding or its correct traffic to the membrane. PMID:24966243

Sanguinetti, Manuel; Amillis, Sotiris; Pantano, Sergio; Scazzocchio, Claudio; Ramon, Ana

2014-01-01

403

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

PubMed

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

Clayden, Jonathan; Lemiègre, Loïc; Helliwell, Madeleine

2007-03-30

404

Structure and Dynamics of Urea/Water Mixtures Investigated by Vibrational Spectroscopy and Molecular Dynamics Simulation  

PubMed Central

Urea/water is an archetypical “biological” mixture, and is especially well known for its relevance to protein thermodynamics, as urea acts as a protein denaturant at high concentration. This behavior has given rise to an extended debate concerning urea’s influence on water structure. Based on a variety of methods and of definitions of water structure, urea has been variously described as a structure-breaker, a structure-maker, or as remarkably neutral towards water. Because of its sensitivity to microscopic structure and dynamics, vibrational spectroscopy can help resolve these debates. We report experimental and theoretical spectroscopic results for the OD stretch of HOD/H2O/urea mixtures (linear IR, 2DIR, and pump-probe anisotropy decay) and for the CO stretch of urea-D4/D2O mixtures (linear IR only). Theoretical results are obtained using existing approaches for water, and a modification of a frequency map developed for acetamide. All absorption spectra are remarkably insensitive to urea concentration, consistent with the idea that urea only very weakly perturbs water structure. Both this work and experiments by Rezus and Bakker, however, show that water’s rotational dynamics are slowed down by urea. Analysis of the simulations casts doubt on the suggestion that urea immobilizes particular doubly hydrogen bonded water molecules. PMID:23841646

Carr, J. K.; Buchanan, L. E.; Schmidt, J. R.; Zanni, M. T.; Skinner, J. L.

2013-01-01

405

Urea uptake enhances barrier function and antimicrobial defense in humans by regulating epidermal gene expression  

PubMed Central

Urea is an endogenous metabolite, known to enhance stratum corneum hydration. Yet, topical urea anecdotally also improves permeability barrier function, and it appears to exhibit antimicrobial activity. Hence, we hypothesized that urea is not merely a passive metabolite, but a small-molecule regulator of epidermal structure and function. In 21 human volunteers, topical urea improved barrier function in parallel with enhanced antimicrobial peptide (LL-37 and ?-defensin-2) expression. Urea both stimulates expression of, and is transported into keratinocytes by two urea transporters, UT-A1 and UT-A2, and by aquaporin 3, 7 and 9. Inhibitors of these urea transporters block the downstream biological effects of urea, which include increased mRNA and protein levels for: (i) transglutaminase-1, involucrin, loricrin and filaggrin; (ii) epidermal lipid synthetic enzymes, and (iii) cathelicidin/LL-37 and ?-defensin-2. Finally, we explored the potential clinical utility of urea, showing that topical urea applications normalized both barrier function and antimicrobial peptide expression in a murine model of atopic dermatitis (AD). Together, these results show that urea is a small-molecule regulator of epidermal permeability barrier function and antimicrobial peptide expression after transporter uptake, followed by gene regulatory activity in normal epidermis, with potential therapeutic applications in diseased skin. PMID:22418868

Grether-Beck, Susanne; Felsner, Ingo; Brenden, Heidi; Kohne, Zippora; Majora, Marc; Marini, Alessandra; Jaenicke, Thomas; Rodriguez-Martin, Marina; Trullas, Carles; Hupe, Melanie; Elias, Peter M.; Krutmann, Jean

2012-01-01

406

Analysis of Blood and Salivary Urea Levels in Patients Undergoing Haemodialysis and Kidney Transplant  

PubMed Central

Aims and Objectives: To determine correlation between the Salivary Urea levels with that of Blood Urea levels. Materials and Methods: Subjects were selected from patients undergoing haemodialysis and patients who had underwent kidney transplantation at Ashwini Hospitals Guntur. The study comprised of 45 patients, of which Haemodialysis group (HD) with 20 patients, Transplant (T) group with 15 patients and 10 patients in control group. Samples of blood and saliva were taken from all the patients to assess the Blood Urea Nitrogen (BUN) and Salivary Urea (SU) levels respectively under strict aseptic precautions. Blood was collected just prior to the dialysis in HD group and in renal transplant (T) patients during their review visit. Informed consent was taken from patients and ethical committee approval taken. Results: There was a statistically significant difference between Blood Urea and Salivary Urea levels in the HD and T group (p<0.05). There was a statistically significant difference between T and Control group with respect to Blood Urea and Salivary Urea levels. The salivary urea levels are slightly higher than blood urea levels in all the study groups. Conclusion: The salivary urea tests can be used in place of blood tests as a non invasive diagnostic tool. Thus, preventing the unnecessary and periodic withdraw of blood which is not only cumbersome but also leads to recurrent infections. PMID:25177630

A, Ravi Kiran; Y, Samata; N, Purnachandrarao Naik; A, Vijay Kumar

2014-01-01

407

Oxidative balance, homocysteine, and uric acid levels in older patients with Late Onset Alzheimer's Disease or Vascular Dementia.  

PubMed

This study aimed to investigate whether Late Onset Alzheimer's Disease (LOAD) and Vascular Dementia (VAD) might be associated with a distinct profile of oxidative stress (OxS) peripheral markers. Serum levels of hydroperoxides, homocysteine, advanced oxidation protein products, uric acid, thiols, and total and residual antioxidant power were assessed in 103 mild cognitive impairment (MCI), 89 LOAD, 54 VAD patients and 48 Controls. Compared with Controls, a similar oxidative unbalance (high hydroperoxides and low residual antioxidant power) was observed in MCI, LOAD and, although less pronounced, VAD. Moreover, individuals with simultaneously high levels of homocysteine and uric acid, both well-known risk factors for cardiovascular disease, had a high probability to be affected by VAD (O.R.:10.50; 95% C.I.: 2.33-47.2), but not LOAD (O.R.: 3.0; 95% C.I.:0.86-10.76) compared with individuals with normal values. Our data suggest that, although they might share a common OxS-related pathogenesis, VAD and LOAD might maintain some distinctive features, with a predominance of "vascular component" in VAD compared with LOAD. PMID:24321755

Cervellati, Carlo; Romani, Arianna; Seripa, Davide; Cremonini, Eleonora; Bosi, Cristina; Magon, Stefania; Passaro, Angelina; Bergamini, Carlo M; Pilotto, Alberto; Zuliani, Giovanni

2014-02-15

408

A comparison of GFR estimating formulae based upon s-cystatin C and s-creatinine and a combination of the two  

Microsoft Academic Search

Background. Current recommendations (KDIGO and NKF-K\\/DOQI) are that patients with chronic kidney dis- eases (CKD) should be classified in stages 1-5 based on GFR. A serum creatinine-based prediction equation (ab- breviated MDRD formula) can be used to estimate GFR (eGFR). Cystatin C has been proposed as an alternative filtration marker to creatinine. We present validation of currently used formulae for

Martin Tidman; Ian Jones

2008-01-01

409

Enzymatic but not compensated Jaffe methods reach the desirable specifications of NKDEP at normal levels of creatinine. Results of the French multicentric evaluation.  

PubMed

The French Society of Clinical Biochemistry conducted this study to compare the accuracy and performances of the best creatinine enzymatic assays and the compensated Jaffe methods from the same manufacturers. Creatinine was measured in 3 serum pools with creatinine levels of 35.9±0.9 ?mol/L, 74.4±1.4 ?mol/L, and 97.9±1.7 ?mol/L (IDMS determination). The performances of the assays (total error that includes the contribution of bias and imprecision) were evaluated using Monte-Carlo simulations and compared against desirable NKDEP criteria. The enzymatic assays always fell within the desirable total Error of 7.6%. By contrast, this requirement was never obtained for the compensated Jaffe methods at the critical level of 74.4±1.4 ?mol/L. Only the compensated Jaffe creatinine on Olympus analyzer reached this specification at 35.9±0.9 and 97.9±1.7 ?mol/L levels. This study demonstrates that, despite substantial improvement regarding traceability to the IDMS reference method and precision, compensated Jaffe creatinine methods, by contrast to enzymatic ones, do not reach the desirable specifications of NKDEP at normal levels of creatinine. PMID:23415696

Boutten, Anne; Bargnoux, Anne-Sophie; Carlier, Marie-Christine; Delanaye, Pierre; Rozet, Eric; Delatour, Vincent; Cavalier, Etienne; Hanser, Anne-Marie; Froissart, Marc; Cristol, Jean-Paul; Piéroni, Laurence

2013-04-18

410

Urea Cycle Enzyme Activities of Liver of the African Lion  

Microsoft Academic Search

IN the course of a continuous survey1,2 on the occurrence and levels of activity of ornithine-urea cycle3 enzymes, an unexpected opportunity was afforded for quantitative measurement of these activities in the instance of the African lion, Felis leo. At the Vilas Park Zoo in Madison (Wisconsin) the director, Mr. Dan Watson, decided that an infirm male lion about twelve years

G. W. Brown

1966-01-01

411

Growth of urea crystals by physical vapor transport  

NASA Technical Reports Server (NTRS)

This work demonstrates that high optical quality crystals of urea can be grown by the physical vapor transport method. The unique features of this method are compared with growth from methanol/water solutions. High growth rates, exceeding 2.5 mm/day, were achieved, and cm-size optical quality single crystals were obtained. Details of the growth technique and the physical properties of the crystals are presented.

Feigelson, R. S.; Route, R. K.; Kao, T.-M.

1985-01-01

412

The response of rice straw varieties to urea treatment  

Microsoft Academic Search

Sixteen rice straw varieties comprising 6 single-crop and 10 double-crop varieties were treated with 40g\\/l urea solution (50g straw per 200ml of solution) for 21 days at 27°C and total and insoluble ash, crude protein, neutral detergent fibre and in vitro digestibility (IVD) were measured after samples were dried at 60°C to constant weight. The mean IVD values across treatments

J. Vadiveloo; J. G. Fadel

2009-01-01

413

Molecular diagnosis of urea cycle disorders: current global scenario.  

PubMed

Urea cycle disorders are a group of inborn error of metabolism, characterized by hyperammonemia, metabolic alkalosis and clinical features of encephalopathy. These are among the commonest types of inborn errors of metabolism with a frequency of 1 in 8,000 to 1 in 30,000 in different population. This encompasses 5 major disorders, corresponding with deficiency of each step in the urea cycle, namely ornithine transcarbamoylase (OTC) deficiency, ar