Infectious precipitants of acute hyperammonemia are associated with indicators of increased morbidity in patients with urea cycle disorders.

Science.gov (United States)

McGuire, Peter J; Lee, Hye-Seung; Summar, Marshall L

2013-12-01

To prospectively characterize acute hyperammonemic episodes in patients with urea cycle disorders (UCDs) in terms of precipitating factors, treatments, and use of medical resources. This was a prospective, longitudinal observational study of hyperammonemic episodes in patients with UCD enrolled in the National Institutes of Health-sponsored Urea Cycle Disorders Consortium Longitudinal Study. An acute hyperammonemic event was defined as plasma ammonia level >100 μmol/L. Physician-reported data regarding the precipitating event and laboratory and clinical variables were recorded in a central database. In our study population, 128 patients with UCD experienced a total of 413 hyperammonemia events. Most patients experienced between 1 and 3 (65%) or between 4 and 6 (23%) hyperammonemia events since study inception, averaging fewer than 1 event/year. The most common identifiable precipitant was infection (33%), 24% of which were upper/lower respiratory tract infections. Indicators of increased morbidity were seen with infection, including increased hospitalization rates (P = .02), longer hospital stays (+2.0 days; P = .003), and increased use of intravenous ammonia scavengers (+45%-52%; P = .003-.03). Infection is the most common precipitant of acute hyperammonemia in patients with UCD and is associated with indicators of increased morbidity (ie, hospitalization rate, length of stay, and use of intravenous ammonia scavengers). These findings suggest that the catabolic and immune effects of infection may be a target for clinical intervention in inborn errors of metabolism. Published by Mosby, Inc.

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

Science.gov (United States)

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

2011-01-01

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

Final report of the safety assessment of Urea.

Science.gov (United States)

2005-01-01

as 2000 mg/kg in acute oral studies using female rats or mice. No signs of toxicity were observed in male piglets dosed orally with up to 4 g/kg Urea for 5 days. Dogs dosed orally with 5 to 30 g/L Urea for 4 to 10 days had signs of toxicity, including weakness, anorexia, vomiting and retching, diarrhea and a decreased body temperature, which led to a deep torpor or coma. No significant microscopic changes were observed in the skin of male nude mice dermally exposed to 100% Urea for 24 h. No observable effect on fetal development was seen in rats and mice dosed orally with an aqueous solution of Urea (2000 mg/kg) on days 10 and 12 of gestation. The mean number of implants, live fetuses, percent fetal resorptions, mean fetal weight, and percent fetuses malformed were comparable to control group. A detergent containing 15% Urea was injected into pregnant ICR-JCl mice and dams and fetuses had no significant differences when compared to control animals. Urea given orally did not enhance the developmental toxicity of N-nitrosomethylurea. Female Sprague-Dawley rats injected in the uterine horn with 0.05 ml Urea on day 3 (preimplantation) or on day 7 (post implantation) exhibited no maternal mortality or morbidity; a dose-dependent reduction in embryo survival was seen with preimplantation treatment. Urea injected intra-amniotically induces mid-trimester abortions in humans. Urea was not genotoxic in several bacterial and mammalian assays; although in assays where Urea was used at a high concentration, genotoxicity was found, many in in vitro assays. Urea is commonly used in studies of DNA because it causes uncoiling of DNA molecules. Urea was not carcinogenic in Fisher 344 rats or C57B1/6 mice fed diets containing up to 4.5% Urea. Exposure of normal human skin to 60% Urea produced no significant irritation in one study, but 5% Urea was slightly irritating and 20% Urea was irritating in other reports. Burning sensations are the most frequently reported effect of Urea used

Unmasked adult-onset urea cycle disorders in the critical care setting.

Science.gov (United States)

Summar, Marshall L; Barr, Frederick; Dawling, Sheila; Smith, Wendy; Lee, Brendan; Singh, Rani H; Rhead, William J; Sniderman King, Lisa; Christman, Brian W

2005-10-01

Most often, urea cycle disorders have been described as acute onset hyperammonemia in the newborn period; however, there is a growing awareness that urea cycle disorders can present at almost any age, frequently in the critical care setting. This article presents three cases of adult-onset hyperammonemia caused by inherited defects in nitrogen processing in the urea cycle, and reviews the diagnosis, management, and pathophysiology of adult-onset urea cycle disorders. Individuals who have milder molecular urea cycle defects can lead a relatively normal life until a severe environmental stress triggers a hyperammonemic crisis. Comorbid conditions such as physical trauma often delay the diagnosis of the urea cycle defect. Prompt recognition and treatment are essential in determining the outcome of these patients.

Disorders of urea cycle: case report

Directory of Open Access Journals (Sweden)

Adolfo Álvarez

2017-08-01

Discussion: Urea cycle disorders are part of innate errors in ammonia detoxification or arginine synthesis, secondary to defects in the enzymes involved in this cycle. Clinical manifestations are secondary to elevated levels of serum ammonia. The treatment is composed of an acute and chronic phase.

Urea, a true uremic toxin: the empire strikes back.

Science.gov (United States)

Lau, Wei Ling; Vaziri, Nosratola D

2017-01-01

Blood levels of urea rise with progressive decline in kidney function. Older studies examining acute urea infusion suggested that urea was well-tolerated at levels 8-10× above normal values. More recent in vitro and in vivo work argue the opposite and demonstrate both direct and indirect toxicities of urea, which probably promote the premature aging phenotype that is pervasive in chronic kidney disease (CKD). Elevated urea at concentrations typically encountered in uremic patients induces disintegration of the gut epithelial barrier, leading to translocation of bacterial toxins into the bloodstream and systemic inflammation. Urea induces apoptosis of vascular smooth muscle cells as well as endothelial dysfunction, thus directly promoting cardiovascular disease. Further, urea stimulates oxidative stress and dysfunction in adipocytes, leading to insulin resistance. Finally, there are widespread indirect effects of elevated urea as a result of the carbamylation reaction, where isocyanic acid (a product of urea catabolism) alters the structure and function of proteins in the body. Carbamylation has been linked with renal fibrosis, atherosclerosis and anaemia. In summary, urea is a re-emerging Dark Force in CKD pathophysiology. Trials examining low protein diet to minimize accumulation of urea and other toxins suggest a clinical benefit in terms of slowing progression of CKD. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

Up-Regulation of P21 Inhibits TRAIL-Mediated Extrinsic Apoptosis, Contributing Resistance to SAHA in Acute Myeloid Leukemia Cells

Directory of Open Access Journals (Sweden)

Xing Wu

2014-08-01

Full Text Available Background/Aim: P21, a multifunctional cell cycle-regulatory molecule, regulates apoptotic cell death. In this study we examined the effect of altered p21 expression on the sensitivity of acute myeloid leukemia cells in response to HDAC inhibitor SAHA treatment and investigated the underlying mechanism. Methods: Stably transfected HL60 cell lines were established in RPMI-1640 with supplementation of G-418. Cell viability was measured by MTT assay. Western blot was applied to assess the protein expression levels of target genes. Cell apoptosis was monitored by AnnexinV-PE/7AAD assay. Results: We showed HL60 cells that that didn't up-regulate p21 expression were more sensitive to SAHA-mediated apoptosis than NB4 and U937 cells that had increased p21 level. Enforced expression of p21 in HL60 cells reduced sensitivity to SAHA and blocked TRAIL-mediated apoptosis. Conversely, p21 silencing in NB4 cells enhanced SAHA-mediated apoptosis and lethality. Finally, we found that combined treatment with SAHA and rapamycin down-regulated p21 and enhanced apoptosis in AML cells. Conclusion: We conclude that up-regulated p21 expression mediates resistance to SAHA via inhibition of TRAIL apoptotic pathway. P21 may serve as a candidate biomarker to predict responsiveness or resistance to SAHA-based therapy in AML patients. In addition, rapamycin may be an effective agent to override p21-mediated resistance to SAHA in AML patients.

Computational regulatory model for detoxification of ammonia from urea cycle in liver

OpenAIRE

ALI, Rashith Muhammad MUBARAK; GURUSAMY, Poornima Devi; RAMACHANDRAN, Selvakumar

2015-01-01

A nondeterministic finite automaton was designed to monitor enzymatic regulation and detoxification of excess ammonia in the urea cycle and its disorders. The designed machine is used for the diagnosis of deficiency and for regulating the expression of any of the enzymes involved with acceptance and rejection states in the urea cycle. The urea cycle is the metabolism of excess nitrogen produced by the breakdown of protein and other nitrogen-containing molecules in liver. Disorder in the urea ...

Hyperpolarized 13C-Urea MRI for the assessment of the urea gradient in the porcine kidney

DEFF Research Database (Denmark)

Søvsø Szocska Hansen, Esben; Stewart, Neil James; Wild, Jim Michael

Renal anatomical and pathophysiological alterations are directly associated with the fluid and electrolyte balance in the kidney, which is regulated by the extracellular corticomedullary osmolality gradient. We introduce a novel magnetic resonance imaging (MRI) approach to monitor...... treatment resulted in an increased urea accumulation in the cortical space. This work demonstrates intra-renal functional assessment with hyperpolarized 13C-urea MRI in multi-papillary kidneys....

Dispersion Interactions between Urea and Nucleobases Contribute to the Destabilization of RNA by Urea in Aqueous Solution

Science.gov (United States)

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

2015-01-01

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

Long-term dietary restriction up-regulates activity and expression of renal arginase II in aging mice.

Science.gov (United States)

Majaw, T; Sharma, R

2017-06-01

Arginase II is a mitochondrial enzyme that catalyses the hydrolysis of L-arginine into urea and ornithine. It is present in other extra-hepatic tissues that lack urea cycle. Therefore, it is plausible that arginase II has a physiological role other than urea cycle which includes polyamine, proline, glutamate synthesis and regulation of nitric oxide production. The high expression of arginase II in kidney, among extrahepatic tissues, might have an important role associated with kidney functions. The present study is aimed to determine the age-associated alteration in the activity and expression of arginase II in the kidney of mice of different ages. The effect of dietary restriction to modulate the agedependent changes of arginase II was also studied. Results showed that renal arginase II activity declines significantly with the progression of age (p less than 0.01 and p less than 0.001 in 6- and 18-month-old mice, respectively as compared to 2-month old mice) and is due to the reduction in its protein as well as the mRNA level (p less than 0.001 in both 6- and 18-month-old mice as compared to 2-month-old mice). Long-term dietary restriction for three months has significantly up-regulated arginase II activity and expression level in both 2- and 18-month-old mice (p less than 0.01 and p less than 0.001, respectively as compared to AL group). These findings clearly indicate that the reducing level of arginase II during aging might have an impact on the declining renal functions. This age-dependent down-regulation of arginase II in the kidney can be attenuated by dietary restriction which may help in the maintenance of such functions.

Studies investigating the excretion of acetyl urea in the milk of dairy cows receiving oral doses of 14C acetyl urea

International Nuclear Information System (INIS)

Bergner, H.; Kijora, C.; Goersch, R.

1976-01-01

2 experimental cows were fed acetyl urea several weeks before the trial was started. The first cow received a daily amount of 200 g and the second cow 855 g. On the first day of experiment both cows were given 5 mCi of 14 C acetyl urea intraruminally. Up to 6 hrs after the beginning of the experiment acetyl urea in blood plasma was shown to contain a higher proportion of 14 C activity than urea. 0.21 g urea and 0.18 g acetyl urea were contained in 1 kg of milk from cow No 1 while 1 kg of milk from cow No 2 contained 0.18 g urea and 0.12 g acetyl urea. The feeding of acetyl urea to dairy cows is not recommended on the basis of the fact that any further contamination of human nutrition with foreign substances should be possibly avoided. (author)

Computational modeling to predict nitrogen balance during acute metabolic decompensation in patients with urea cycle disorders.

Science.gov (United States)

MacLeod, Erin L; Hall, Kevin D; McGuire, Peter J

2016-01-01

Nutritional management of acute metabolic decompensation in amino acid inborn errors of metabolism (AA IEM) aims to restore nitrogen balance. While nutritional recommendations have been published, they have never been rigorously evaluated. Furthermore, despite these recommendations, there is a wide variation in the nutritional strategies employed amongst providers, particularly regarding the inclusion of parenteral lipids for protein-free caloric support. Since randomized clinical trials during acute metabolic decompensation are difficult and potentially dangerous, mathematical modeling of metabolism can serve as a surrogate for the preclinical evaluation of nutritional interventions aimed at restoring nitrogen balance during acute decompensation in AA IEM. A validated computational model of human macronutrient metabolism was adapted to predict nitrogen balance in response to various nutritional interventions in a simulated patient with a urea cycle disorder (UCD) during acute metabolic decompensation due to dietary non-adherence or infection. The nutritional interventions were constructed from published recommendations as well as clinical anecdotes. Overall, dextrose alone (DEX) was predicted to be better at restoring nitrogen balance and limiting nitrogen excretion during dietary non-adherence and infection scenarios, suggesting that the published recommended nutritional strategy involving dextrose and parenteral lipids (ISO) may be suboptimal. The implications for patients with AA IEM are that the medical course during acute metabolic decompensation may be influenced by the choice of protein-free caloric support. These results are also applicable to intensive care patients undergoing catabolism (postoperative phase or sepsis), where parenteral nutritional support aimed at restoring nitrogen balance may be more tailored regarding metabolic fuel selection.

Peak hyperammonemia and atypical acute liver failure: The eruption of an urea cycle disorder during hyperemesis gravidarum.

Science.gov (United States)

Weiss, Nicolas; Mochel, Fanny; Rudler, Marika; Demeret, Sophie; Lebray, Pascal; Conti, Filomena; Galanaud, Damien; Ottolenghi, Chris; Bonnefont, Jean-Paul; Dommergues, Marc; Bernuau, Jacques; Thabut, Dominique

2017-09-20

Inborn urea cycle disorders are under-recognised metabolic causes of hyperammonemia in adults. A 28-year-old primigravida, seven weeks pregnant, affected by hyperemesis gravidarum developed acute liver injury (ALI) and then acute liver failure (ALF) in less than 48 h. Because the patient developed atypical features, especially mildly elevated aminotransferases contrasting with very high blood ammonia levels (281 μmol/L), concomitant with normal serum creatinine, an inborn error of metabolism was suspected. We performed emergency metabolic analyses, stopped all protein intake and started with intravenous (i.v.) high caloric intake, nitrogen scavenger drugs and haemodialysis. The neurological and hepatic status of the patient quickly improved together with normalisation of her ammonemia levels. High plasma glutamine and urinary orotic acid, alongside low plasma arginine, citrulline and ornithine were suggestive of an ornithine transcarbamylase deficiency, later confirmed by molecular analyses. Foetal sex was female, as determined by foetal DNA analysis in maternal blood, and foetal development was unremarkable throughout the pregnancy. Delivery was induced at 39 weeks with a close monitoring of ammonemia levels and i.v. perfusion of carbohydrates and lipids during labour and immediately post-partum to avoid hypercatabolism. Delivery was uneventful and the patient delivered a healthy female baby. Urea cycle disorders should be contemplated in non-jaundiced patients with ALI or ALF, severe hyperammonemia and normal serum creatinine regardless of serum aminotransferase levels. The prompt recognition of this rare condition and the rapid initiation of adequate metabolic therapy are mandatory to prevent irreversible neurological sequelae and to avoid liver transplantation. Copyright © 2017 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Effect of Microbial Interaction on Urea Metabolism in Chinese Liquor Fermentation.

Science.gov (United States)

Wu, Qun; Lin, Jianchun; Cui, Kaixiang; Du, Rubin; Zhu, Yang; Xu, Yan

2017-12-20

Urea is the primary precursor of the carcinogen ethyl carbamate in fermented foods. Understanding urea metabolism is important for controlling ethyl carbamate production. Using Chinese liquor as a model system, we used metatranscriptome analysis to investigate urea metabolism in spontaneous food fermentation processes. Saccharomyces cerevisiae was dominant in gene transcription for urea biosynthesis and degradation. Lysinibacillus sphaericus was dominant for urea degradation. S. cerevisiae degraded 18% and L. sphaericus degraded 13% of urea in their corresponding single cultures, whereas they degraded 56% of urea in coculture after 12 h. Compared to single cultures, transcription of CAR1, DAL2, and argA, which are related to urea biosynthesis, decreased by 51, 36, and 69% in coculture, respectively. Transcription of DUR1 and ureA, which are related to urea degradation, increased by 227 and 70%, respectively. Thus, coexistence of the two strains promoted degradation of urea via transcriptional regulation of genes related to urea metabolism.

Hydroponics versus field lysimeter studies of urea, ammonium and nitrate uptake by oilseed rape (Brassica napus L.).

Science.gov (United States)

Arkoun, Mustapha; Sarda, Xavier; Jannin, Laëtitia; Laîné, Philippe; Etienne, Philippe; Garcia-Mina, José-Maria; Yvin, Jean-Claude; Ourry, Alain

2012-09-01

N-fertilizer use efficiencies are affected by their chemical composition and suffer from potential N-losses by volatilization. In a field lysimeter experiment, (15)N-labelled fertilizers were used to follow N uptake by Brassica napus L. and assess N-losses by volatilization. Use of urea with NBPT (urease inhibitor) showed the best efficiency with the lowest N losses (8% of N applied compared with 25% with urea alone). Plants receiving ammonium sulphate, had similar yield achieved through a better N mobilization from vegetative tissues to the seeds, despite a lower N uptake resulting from a higher volatilization (43% of applied N). Amounts of (15)N in the plant were also higher when plants were fertilized with ammonium nitrate but N-losses reached 23% of applied N. In parallel, hydroponic experiments showed a deleterious effect of ammonium and urea on the growth of oilseed rape. This was alleviated by the nitrate supply, which was preferentially taken up. B. napus was also characterized by a very low potential for urea uptake. BnDUR3 and BnAMT1, encoding urea and ammonium transporters, were up-regulated by urea, suggesting that urea-grown plants suffered from nitrogen deficiency. The results also suggested a role for nitrate as a signal for the expression of BnDUR3, in addition to its role as a major nutrient. Overall, the results of the hydroponic study showed that urea itself does not contribute significantly to the N nutrition of oilseed rape. Moreover, it may contribute indirectly since a better use efficiency for urea fertilizer, which was further increased by the application of a urease inhibitor, was observed in the lysimeter study.

Studies investigating the excretion of acetyl urea in the milk of dairy cows receiving oral doses of /sup 14/C acetyl urea

Energy Technology Data Exchange (ETDEWEB)

Bergner, H; Kijora, C; Goersch, R [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin

1976-01-01

2 experimental cows were fed acetyl urea several weeks before the trial was started. The first cow received a daily amount of 200 g and the second cow 855 g. On the first day of experiment both cows were given 5 mCi of /sup 14/C acetyl urea intraruminally. Up to 6 hrs after the beginning of the experiment acetyl urea in blood plasma was shown to contain a higher proportion of /sup 14/C activity than urea. 0.21 g urea and 0.18 g acetyl urea were contained in 1 kg of milk from cow No 1 while 1 kg of milk from cow No 2 contained 0.18 g urea and 0.12 g acetyl urea. The feeding of acetyl urea to dairy cows is not recommended on the basis of the fact that any further contamination of human nutrition with foreign substances should be possibly avoided.

Corticostriatal Regulation of Acute Pain

Directory of Open Access Journals (Sweden)

Erik Martinez

2017-05-01

Full Text Available The mechanisms for acute pain regulation in the brain are not well understood. The prefrontal cortex (PFC provides top-down control of emotional processes, and it projects to the nucleus accumbens (NAc. This corticostriatal projection forms an important regulatory pathway within the brain’s reward system. Recently, this projection has been suggested to control both sensory and affective phenotypes specifically associated with chronic pain. As this projection is also known to play a role in the transition from acute to chronic pain, we hypothesized that this corticostriatal circuit can also exert a modulatory function in the acute pain state. Here, we used optogenetics to specifically target the projection from the PFC to the NAc. We tested sensory pain behaviors with Hargreaves’ test and mechanical allodynia, and aversive pain behaviors with conditioned place preference (CPP test. We found that the activation of this corticostriatal circuit gave rise to bilateral relief from peripheral nociceptive inputs. Activation of this circuit also provided important control for the aversive response to transient noxious stimulations. Hence, our results support a novel role for corticostriatal circuitry in acute pain regulation.

Urea and deuterium mixtures at high pressures

Energy Technology Data Exchange (ETDEWEB)

Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)

2015-03-28

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

Reassessment of primed constant-infusion tracer method to measure urea kinetics

International Nuclear Information System (INIS)

Jahoor, F.; Wolfe, R.R.

1987-01-01

The validity of the primed constant-infusion tracer technique to make short-term measurements of urea production rates (R/sub a/) in humans in a physiological steady state and during disruption of steady state was evaluated. Four subjects received a primed constant infusion (P/I = 560 min) of [ 13 C]urea for 8 h. A plateau in urea enrichment was reached after 2 h and maintained throughout. When [ 13 C]- and [ 18 O]urea were simultaneously infused into four subjects at P/I ratios of 560:1 and 360:1, respectively, both tracers reached plateau enrichment at the same time (2-4 h). The enrichment at plateau was a function of the infusion rate rather than the priming dose, and calculated urea R/sub a/ was the same with either prime. In five additional experiments the technique responded acutely to a physiological perturbation (alanine infusion) in a dose-dependent manner. The results confirm that this technique is appropriate for short-term measurements of urea R/sub a/, and the requirement for accuracy in estimating the priming dose is not impractically stringent

Urea metabolism in Barbari kids d on urea molasses diets

International Nuclear Information System (INIS)

Lal, M.; Singh, U.B.; Verma, D.N.; Ranjhan, S.K.

1974-01-01

The entry rates of urea into the body pool of urea were estimated in Barbari kids using a single injection isotope dilution technique using 14 C-urea. The excretion rates of urea were calculated by estimating total urine output over 24 h and urea content. (M.G.B.)

Production of granules of urea, urea-ammonium sulphate and urea-potassium chloride enriched with 15N

International Nuclear Information System (INIS)

Bendassolli, J.A.

1991-01-01

Using a pearling tower it was possible to produce granulated urea, and granulated mixtures of ammonium sulphate and urea, potassium chloride and urea, Labelled in 15 N. Granulated urea with 1, 2, 3 and 4 mm of diameter was obtained using a system with a heating controller. A low concentration of biuret was observed in the granules produced ( 15 N-Labelled ( 15 NH 4' 15 NH 2 ) with variable proportion of ammonium sulphate and urea. (author)

Urea ammoniation compared to urea supplementation as a method ...

African Journals Online (AJOL)

Urea ammoniation compared to urea supplementation as a method of improving the nutritive value of wheat straw for sheep. S.W.P. Cloete, N.M. Kritzinger. Winter Rainfall Region, Eisenburg. The ammoniation of wheat straw by urea in a stack method was in- vestigated and compared to urea supplemented and untreated ...

High-Density Lipoprotein Cholesterol, Blood Urea Nitrogen, and Serum Creatinine Can Predict Severe Acute Pancreatitis.

Science.gov (United States)

Hong, Wandong; Lin, Suhan; Zippi, Maddalena; Geng, Wujun; Stock, Simon; Zimmer, Vincent; Xu, Chunfang; Zhou, Mengtao

2017-01-01

Early prediction of disease severity of acute pancreatitis (AP) would be helpful for triaging patients to the appropriate level of care and intervention. The aim of the study was to develop a model able to predict Severe Acute Pancreatitis (SAP). A total of 647 patients with AP were enrolled. The demographic data, hematocrit, High-Density Lipoprotein Cholesterol (HDL-C) determinant at time of admission, Blood Urea Nitrogen (BUN), and serum creatinine (Scr) determinant at time of admission and 24 hrs after hospitalization were collected and analyzed statistically. Multivariate logistic regression indicated that HDL-C at admission and BUN and Scr at 24 hours (hrs) were independently associated with SAP. A logistic regression function (LR model) was developed to predict SAP as follows: -2.25-0.06 HDL-C (mg/dl) at admission + 0.06 BUN (mg/dl) at 24 hours + 0.66 Scr (mg/dl) at 24 hours. The optimism-corrected c-index for LR model was 0.832 after bootstrap validation. The area under the receiver operating characteristic curve for LR model for the prediction of SAP was 0.84. The LR model consists of HDL-C at admission and BUN and Scr at 24 hours, representing an additional tool to stratify patients at risk of SAP.

JBP485 improves gentamicin-induced acute renal failure by regulating the expression and function of Oat1 and Oat3 in rats

Energy Technology Data Exchange (ETDEWEB)

Guo, Xinjin [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian (China); Meng, Qiang; Liu, Qi; Wang, Changyuan; Sun, Huijun; Peng, Jinyong; Ma, Xiaochi [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian (China); Provincial Key Laboratory for Pharmacokinetics and Transport, Dalian Medical University, Liaoning (China); Kaku, Taiichi [Japan Bioproducts Industry Co. Ltd., Tomigaya, Shibuya-ku, Tokyo (Japan); Liu, Kexin, E-mail: kexinliu@dlmedu.edu.cn [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian (China); Provincial Key Laboratory for Pharmacokinetics and Transport, Dalian Medical University, Liaoning (China)

2013-09-01

We investigated the effects of JBP485 (an anti-inflammatory dipeptide and a substrate of OAT) on regulation of the expression and function of renal Oat1 and Oat3, which can accelerate the excretion of accumulated uremic toxins (e.g. indoxyl sulfate) in the kidney to improve gentamicin-induced ARF in rats. JBP485 caused a significant decrease in the accumulation of endogenous substances (creatinine, blood urea nitrogen and indoxyl sulfate) in vivo, an increase in the excretion of exogenous compounds (lisinopril and inulin) into urine, and up-regulation of the expressions of renal Oat1 and Oat3 in the kidney tissues and slices via substrate induction. To determine the effect of JBP485 on the accelerated excretion of uremic toxins mediated by Oat1 and Oat3, the mRNA and protein expression levels of renal basolateral Oats were assessed by quantitative real-time PCR, western blot, immunohistochemical analysis and an immunofluorescence method. Gentamicin down-regulated the expression of Oats mRNA and protein in rat kidney, and these effects were reversed after administration of JBP485. In addition, JBP485 caused a significant decrease in MPO and MDA levels in the kidney, and improved the pathological condition of rat kidney. These results indicated that JBP485 improved acute renal failure by increasing the expression and function of Oat1 and Oat3, and by decreasing overoxidation of the kidney in gentamicin-induced ARF rats. - Highlights: • JBP485 could up-regulate function and expression of Oat1 and Oat3 in kidney. • Effects of JBP485 on ARF are mediated by stimulating excretion of uremic toxins. • JBP485 protected against gentamicin-induced ARF by decreasing MPO and MDA.

Neuropsychiatric manifestations in late-onset urea cycle disorder patients

OpenAIRE

Serrano Mercedes L.; Martins Cecilia E.; Pérez-Dueñas Belén; Gómez-López Lilian; Murgui Empar; Fons Carmen; García-Cazorla Ángels; Artuch Rafael M D; Jara Fernando; Arranz José Antonio; Häberle Johannes; Briones Paz; Campistol Jaume M D; Pineda Mercè; Vilaseca María Antònia Antonia

2010-01-01

Inherited urea cycle disorders represent one of the most common groups of inborn errors of metabolism. Late onset urea cycle disorders caused by partial enzyme deficiencies may present with unexpected clinical phenotypes. We report 9 patients followed up in our hospital presenting late onset urea cycle disorders who initially manifested neuropsychiatric/neurodevelopmental symptoms (the most prevalent neuropsychiatric/neurodevelopmental diagnoses were mental retardation attention deficit hyper...

Identification of elevated urea as a severe, ubiquitous metabolic defect in the brain of patients with Huntington's disease.

Science.gov (United States)

Patassini, Stefano; Begley, Paul; Reid, Suzanne J; Xu, Jingshu; Church, Stephanie J; Curtis, Maurice; Dragunow, Mike; Waldvogel, Henry J; Unwin, Richard D; Snell, Russell G; Faull, Richard L M; Cooper, Garth J S

Huntington's disease (HD) is a neurodegenerative disorder wherein the aetiological defect is a mutation in the Huntington's gene (HTT), which alters the structure of the huntingtin protein through the lengthening of a polyglutamine tract and initiates a cascade that ultimately leads to dementia and premature death. However, neurodegeneration typically manifests in HD only in middle age, and processes linking the causative mutation to brain disease are poorly understood. Here, our objective was to elucidate further the processes that cause neurodegeneration in HD, by measuring levels of metabolites in brain regions known to undergo varying degrees of damage. We applied gas-chromatography/mass spectrometry-based metabolomics in a case-control study of eleven brain regions in short post-mortem-delay human tissue from nine well-characterized HD patients and nine controls. Unexpectedly, a single major abnormality was evident in all eleven brain regions studied across the forebrain, midbrain and hindbrain, namely marked elevation of urea, a metabolite formed in the urea cycle by arginase-mediated cleavage of arginine. Urea cycle activity localizes primarily in the liver, where it functions to incorporate protein-derived amine-nitrogen into urea for recycling or urinary excretion. It also occurs in other cell-types, but systemic over-production of urea is not known in HD. These findings are consistent with impaired local urea regulation in brain, by up-regulation of synthesis and/or defective clearance. We hypothesize that defective brain urea metabolism could play a substantive role in the pathogenesis of neurodegeneration, perhaps via defects in osmoregulation or nitrogen metabolism. Brain urea metabolism is therefore a target for generating novel monitoring/imaging strategies and/or therapeutic interventions aimed at ameliorating the impact of HD in patients. Copyright © 2015 Elsevier Inc. All rights reserved.

Alcoholic Hepatitis Markedly Decreases the Capacity for Urea Synthesis.

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Emilie Glavind

Full Text Available Data on quantitative metabolic liver functions in the life-threatening disease alcoholic hepatitis are scarce. Urea synthesis is an essential metabolic liver function that plays a key regulatory role in nitrogen homeostasis. The urea synthesis capacity decreases in patients with compromised liver function, whereas it increases in patients with inflammation. Alcoholic hepatitis involves both mechanisms, but how these opposite effects are balanced remains unclear. Our aim was to investigate how alcoholic hepatitis affects the capacity for urea synthesis. We related these findings to another measure of metabolic liver function, the galactose elimination capacity (GEC, as well as to clinical disease severity.We included 20 patients with alcoholic hepatitis and 7 healthy controls. The urea synthesis capacity was quantified by the functional hepatic nitrogen clearance (FHNC, i.e., the slope of the linear relationship between the blood α-amino nitrogen concentration and urea nitrogen synthesis rate during alanine infusion. The GEC was determined using blood concentration decay curves after intravenous bolus injection of galactose. Clinical disease severity was assessed by the Glasgow Alcoholic Hepatitis Score and Model for End-Stage Liver Disease (MELD score.The FHNC was markedly decreased in the alcoholic hepatitis patients compared with the healthy controls (7.2±4.9 L/h vs. 37.4±6.8 L/h, P<0.01, and the largest decrease was observed in those with severe alcoholic hepatitis (4.9±3.6 L/h vs. 9.9±4.9 L/h, P<0.05. The GEC was less markedly reduced than the FHNC. A negative correlation was detected between the FHNC and MELD score (rho = -0.49, P<0.05.Alcoholic hepatitis markedly decreases the urea synthesis capacity. This decrease is associated with an increase in clinical disease severity. Thus, the metabolic failure in alcoholic hepatitis prevails such that the liver cannot adequately perform the metabolic up-regulation observed in other stressful

Effect of urea on protein-ligand association.

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Stepanian, Lora; Son, Ikbae; Chalikian, Tigran V

2017-12-01

We combine experimental and theoretical approaches to investigate the influence of a cosolvent on a ligand-protein association event. We apply fluorescence measurements to determining the affinity of the inhibitor tri-N-acetylglucosamine [(GlcNAc) 3 ] for lysozyme at urea concentrations ranging from 0 to 8M. Notwithstanding that, at room temperature and neutral pH, lysozyme retains its native conformation up to the solubility limit of urea, the affinity of (GlcNAc) 3 for the protein steadily decreases as the concentration of urea increases. We analyze the urea dependence of the binding free energy within the framework of a simplified statistical thermodynamics-based model that accounts for the excluded volume effect and direct solute-solvent interactions. The analysis reveals that the detrimental action of urea on the inhibitor-lysozyme binding originates from competition between the free energy contributions of the excluded volume effect and direct solute-solvent interactions. The free energy contribution of direct urea-solute interactions narrowly overcomes the excluded volume contribution thereby resulting in urea weakening the protein-ligand association. More broadly, the successful application of the simple model employed in this work points to the possibility of its use in quantifying the stabilizing/destabilizing action of individual cosolvents on biochemical folding and binding reactions. Copyright © 2016 Elsevier B.V. All rights reserved.

Urea metabolism in plants.

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Witte, Claus-Peter

2011-03-01

Urea is a plant metabolite derived either from root uptake or from catabolism of arginine by arginase. In agriculture, urea is intensively used as a nitrogen fertilizer. Urea nitrogen enters the plant either directly, or in the form of ammonium or nitrate after urea degradation by soil microbes. In recent years various molecular players of plant urea metabolism have been investigated: active and passive urea transporters, the nickel metalloenzyme urease catalyzing the hydrolysis of urea, and three urease accessory proteins involved in the complex activation of urease. The degradation of ureides derived from purine breakdown has long been discussed as a possible additional metabolic source for urea, but an enzymatic route for the complete hydrolysis of ureides without a urea intermediate has recently been described for Arabidopsis thaliana. This review focuses on the proteins involved in plant urea metabolism and the metabolic sources of urea but also addresses open questions regarding plant urea metabolism in a physiological and agricultural context. The contribution of plant urea uptake and metabolism to fertilizer urea usage in crop production is still not investigated although globally more than half of all nitrogen fertilizer is applied to crops in the form of urea. Nitrogen use efficiency in crop production is generally well below 50% resulting in economical losses and creating ecological problems like groundwater pollution and emission of nitric oxides that can damage the ozone layer and function as greenhouse gasses. Biotechnological approaches to improve fertilizer urea usage bear the potential to increase crop nitrogen use efficiency. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Mechanisms of molecular transport through the urea channel of Helicobacter pylori

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McNulty, Reginald; Ulmschneider, Jakob P.; Luecke, Hartmut; Ulmschneider, Martin B.

2013-12-01

Helicobacter pylori survival in acidic environments relies on cytoplasmic hydrolysis of gastric urea into ammonia and carbon dioxide, which buffer the pathogen’s periplasm. Urea uptake is greatly enhanced and regulated by HpUreI, a proton-gated inner membrane channel protein essential for gastric survival of H. pylori. The crystal structure of HpUreI describes a static snapshot of the channel with two constriction sites near the center of the bilayer that are too narrow to allow passage of urea or even water. Here we describe the urea transport mechanism at atomic resolution, revealed by unrestrained microsecond equilibrium molecular dynamics simulations of the hexameric channel assembly. Two consecutive constrictions open to allow conduction of urea, which is guided through the channel by interplay between conserved residues that determine proton rejection and solute selectivity. Remarkably, HpUreI conducts water at rates equivalent to aquaporins, which might be essential for efficient transport of urea at small concentration gradients.

Effect of urea supplemented and urea treated straw based diet on milk urea concentration in crossbred Karan-Fries cows

Directory of Open Access Journals (Sweden)

Sunil Kumar Sirohi

2010-01-01

Full Text Available The study was undertaken to evaluate the effect of urea supplemented and urea treated straw based diet on milk ureaconcentration. Six multiparous crossbred Karan-Fries (Holstein Friesian ✕ Tharparkar cows were blocked into threegroups of nearly equal body weight, DIM, milk yield and milk fat content and were randomized into a 3 ✕ 3 Latin squaredesign with 3-week period. Three experimental diets were fed to the animals. Composition of these diets were: Diet 1green maize, wheat straw and concentrate mixture; Diet 2 green maize, wheat straw, concentrate mixture (urea supplementedand molasses; Diet 3 green maize (4 % of total DM, 4 % urea treated wheat straw and concentrate mixture.Intake of DM and CP did not vary across the diets. Intake of digestible crude protein (DCP was found significantlyhigher in diet 2, while ME and NEL intakes were found significantly lower in diet 3 but did not differ between diets 1and 2. Average milk and plasma urea concentrations (mg dl-1 were found 29.2 ± 2.6, 45.3 ± 0.9, 34.5 ± 2.3 and 28.9± 2.4, 36.6 ± 1.4, 33.9 ± 2.2, respectively in diet 1, diet 2 and diet 3. Urea concentrations in morning milk sampleswere found significantly lower than noon or evening samples in all the three diets. Concentrations of urea in milk andplasma were found closely correlated (r = 0.94 and the regression equation developed was, plasma urea = 8.90 (.89+ .79 (.02 milk urea. Intake (g of DCP than CP, per unit (MCal of ME was found more closely associated with milk ureaconcentration. The study revealed that urea supplementation and urea treated straw based diet increased urea concentrationsignificantly in milk and plasma. Morning milk urea values that estimated at a time gap of 15 hr since last majorfeeding may be considered as the lowest level and can be used for interpretation to monitor feeding adequacy or reproductiveperformances in dairy cows.

[Separation of gamma linolenic acid from evening primrose oil with urea inclusion--orthogonal experiment of optimizing technological parameters and observation of urea inclusion compound I].

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Wang, Hua; Ling, Man; Xue, Gang; Liu, Fengxia; Guo, Shuxian

2010-05-01

The influence on the urea inclusion compound under different conditions (allocated proportion, time of inclusion, temperature of inclusion) were studied through the orthogonal test, and theoretical reference of urea inclusion process for further optimization wound be offered. The orthogonal experiment was adopted, and microscope was used to observe the shape, aperture size of the urea inclusion compound under different technological parameters, the GC was employed to inspect the purity of GLA. The results indicated that the ratio of fatty acids and urea, inclusion of temperature, time of inclusion had great effect on urea inclusion compound. The three factors and its interactions significantly affected the purity of GLA. The results also showed that the best process was that the ratio of fatty acids and urea was 1 : 3, temperature of inclusion was--15 degrees C, time of inclusion was 24 h. Under the best condition, the purity of GLA reach up to 95.575 9%; and it is feasible to observe the shape and the amount of the urea inclusion compound to reflect and guide the urea inclusion technology.

Glycerol and urea can be used to increase skin permeability in reduced hydration conditions.

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Björklund, Sebastian; Engblom, Johan; Thuresson, Krister; Sparr, Emma

2013-12-18

The natural moisturizing factor (NMF) is a group of hygroscopic molecules that is naturally present in skin and protects from severe drying. Glycerol and urea are two examples of NMF components that are also used in skin care applications. In the present study, we investigate the influence of glycerol and urea on the permeability of a model drug (metronidazole, Mz) across excised pig skin membranes at different hydrating conditions. The degree of skin hydration is regulated by the gradient in water activity across the membrane, which in turn depends on the water activity of the formulation in contact with the skin membrane. Here, we determine the water activity of all formulations employed using an isothermal calorimetric method. Thus, the gradient in water activity is controlled by a novel experimental set-up with well-defined boundary conditions on both sides of the skin membrane. The results demonstrate that glycerol and urea can retain high steady state flux of Mz across skin membranes at dehydrating conditions, which otherwise would decrease the permeability due to dehydration. X-ray diffraction measurements are performed to give insight into the effects of glycerol and urea on SC molecular organization. The novel steady state flux results can be related to the observation that water, glycerol, and urea all affect the structural features of the SC molecular components in a similar manner. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Increases in urea synthesis and the ornithine-urea cycle capacity in the giant African snail, Achatina fulica, during fasting or aestivation, or after the injection with ammonium chloride.

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Hiong, Kum Chew; Loong, Ai May; Chew, Shit Fun; Ip, Yuen Kwong

2005-12-01

The objectives of this study are to determine whether a full complement of ornithine-urea cycle (OUC) enzymes is present in the hepatopancreas of the giant African snail Achatina fulica, and to investigate whether the rate of urea synthesis and the OUC capacity can be up-regulated during 23 days of fasting or aestivation, or 24 hr post-injection with NH(4)Cl (10 micromol g(-1) snail) into the foot muscle. A. fulica is ureotelic and a full complement of OUC enzymes, including carbamoyl phosphate synthetase III (CPS III), was detected from its hepatopancreas. There were significant increases in the excretion of NH(4)(+), NH(3) and urea in fasting A. fulica. Fasting had no significant effect on the tissue ammonia contents, but led to a progressive accumulation of urea, which was associated with an 18-fold increase in the rate of urea synthesis. Because fasting took place in the presence of water and because there was no change in water contents in the foot muscle and hepatopancreas, it can be concluded that the function of urea accumulation in fasting A. fulica was unrelated to water retention. Aestivation in arid conditions led to a non-progressive accumulation of urea in A. fulica. During the first 4 days and the last 3 days of the 23-day aestivation period, experimental snails exhibited significantly greater rates of urea synthesis compared with fasted snails. These increases were associated with significant increases in activities of various OUC enzymes, except CPS III, in the hepatopancreas. However, the overall urea accumulation in snails aestivated and snails fasted for 23 days were comparable. Therefore, the classical hypothesis that urea accumulation occurred to prevent water loss through evaporation during aestivation in terrestrial pulmonates may not be valid. Surprisingly, there were no accumulations of ammonia in the foot muscle and hepatopancreas of A. fulica 12 or 24 hr after NH(4)Cl was injected into the foot muscle. In contrast, the urea content in

Urea kinetics during sustained low-efficiency dialysis in critically ill patients requiring renal replacement therapy.

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Marshall, Mark R; Golper, Thomas A; Shaver, Mary J; Alam, Muhammad G; Chatoth, Dinesh K

2002-03-01

Continuous renal replacement therapies have practical and theoretical advantages compared with conventional intermittent hemodialysis in hemodynamically unstable or severely catabolic patients with acute renal failure (ARF). Sustained low-efficiency dialysis (SLED) is a hybrid modality introduced July 1998 at the University of Arkansas for Medical Sciences that involves the application of a conventional hemodialysis machine with reduced dialysate and blood flow rates for 12-hour nocturnal treatments. Nine critically ill patients with ARF were studied during a single SLED treatment to determine delivered dialysis dose and the most appropriate model for the description of urea kinetics during treatment. Five patients were men, mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 28.9 and mean weight was 92.5 kg. Kt/V was determined by the reference method of direct dialysate quantification (DDQ) combined with an equilibrated postdialysis plasma water urea nitrogen (PUN) concentration and four other methods that were either blood or dialysate based, single or double pool, or model independent (whole-body kinetic method). Solute removal indices (SRIs) were determined from net urea removal and urea distribution volume supplied from DDQ (reference method) and by mass balance using variables supplied from blood-based formal variable-volume single-pool (VVSP) urea kinetic modeling. Equivalent renal urea clearances (EKRs) were calculated from urea generation rates and time-averaged concentrations for PUN based on weekly mass balance with kinetic variables supplied by either DDQ (reference method) or formal blood-based VVSP modeling. Mean Kt/V determined by the reference method was 1.40 and not significantly different when determined by formal VVSP modeling, DDQ using an immediate postdialysis PUN, or the whole-body kinetic method. Correction of single-pool Kt/V by a Daugirdas rate equation did not yield plausible results. Mean SRI and EKR by the

Urea hydrolysis and ammonia volatilization from some urea based fertilizers applied to rice

International Nuclear Information System (INIS)

Misra, C.; Jena, D.; Bandyopadhyay, K.K.; Schepers, J.S.

1995-01-01

Field experiments were carried out in replicated microplots (1 m x 1 m) with rice (cv. Pathara) to study urea hydrolysis using several urea based N-fertilizer sources. Results indicated highly significant urea based N-fertilizers, among which urea super granule (USG) and prilled urea (PU) (applied in two splits) could be rated as the most efficient sources of N. Based on measured ammonia volatilization loss, NH 2 -N concentration in flood water and soil solution (following fertilizer application); urea hydrolysis was observed to be faster in the case of PU, USG, PU + ECC (encapsulated calcium carbide) and UNP (urea nitro phosphate) (19-19-0) than in the case of GCU (gypsum coated urea) and UNP (27-9-0) treatments. Based on the 15 N tagged prilled urea experiment, it is observed that about 24 per cent of fertilizer nitrogen was utilized by the crop in closed system as compared to 18 per cent in natural free system. (author). 5 refs., 2 figs., 4 tabs

Deposits from Creams Containing 20% (w/w) Urea and Suppression of Crystallization (Part 2): Novel Analytical Methods of Urea Accumulated in the Stratum Corneum by Tape stripping and Colorimetry.

Science.gov (United States)

Goto, Norio; Morita, Yutaka; Terada, Katsuhide

2016-01-01

The transfer of urea from a urea formulation to the stratum corneum varies with the formulation base and form, and impacts the formulation's therapeutic effect. Consequently, determining the amount of urea transferred is essential for developing efficient formulations. This study assessed a simple method for measuring the amount of urea accumulated in the stratum corneum. Conventional methods rely on labeling urea used in the formulation with radiocarbon ((14)C) or other radioactive isotopes (RIs), retrieving the transferred urea from the stratum corneum by tape stripping, then quantitating the urea. The handling and use of RIs, however, is subject to legal regulation and can only be performed in sanctioned facilities, so methods employing RIs are neither simple nor convenient. We therefore developed a non-radiolabel method "tape stripping-colorimetry (T-C)" that combines tape stripping with colorimetry (urease-glutamate dehydrogenase (GLDH)) for the quantitative measurement of urea. Urea in the stratum corneum is collected by tape stripping and measured using urease-GLDH, which is commonly used to measure urea nitrogen in blood tests. The results indicate that accurate urea measurement by the T-C method requires the application of 1400 mg (on hairless rats) of a 20% urea solution on a 50 cm(2) (5×10 cm) area. Further, we determined the amount of urea accumulated in the stratum corneum using formulations with different urea concentrations, and the time course of urea accumulation from formulations differing in the rate of urea crystallization. We demonstrate that the T-C method is simple and convenient, with no need for (14)C or other RIs.

Urea and Ammonia Metabolism and the Control of Renal Nitrogen Excretion

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Mitch, William E.; Sands, Jeff M.

2015-01-01

Renal nitrogen metabolism primarily involves urea and ammonia metabolism, and is essential to normal health. Urea is the largest circulating pool of nitrogen, excluding nitrogen in circulating proteins, and its production changes in parallel to the degradation of dietary and endogenous proteins. In addition to serving as a way to excrete nitrogen, urea transport, mediated through specific urea transport proteins, mediates a central role in the urine concentrating mechanism. Renal ammonia excretion, although often considered only in the context of acid-base homeostasis, accounts for approximately 10% of total renal nitrogen excretion under basal conditions, but can increase substantially in a variety of clinical conditions. Because renal ammonia metabolism requires intrarenal ammoniagenesis from glutamine, changes in factors regulating renal ammonia metabolism can have important effects on glutamine in addition to nitrogen balance. This review covers aspects of protein metabolism and the control of the two major molecules involved in renal nitrogen excretion: urea and ammonia. Both urea and ammonia transport can be altered by glucocorticoids and hypokalemia, two conditions that also affect protein metabolism. Clinical conditions associated with altered urine concentrating ability or water homeostasis can result in changes in urea excretion and urea transporters. Clinical conditions associated with altered ammonia excretion can have important effects on nitrogen balance. PMID:25078422

Urea in Milk

OpenAIRE

Projectsatbangalore

2017-01-01

This paper describes the design of a low-cost, portable instrument using CO2 and NH3 gas sensor technology to quantify and differentiate milk samples containing excess urea. Milk containing urea, in presence of urease enzyme hydrolyses urea to form ammonia and carbon dioxide.

Ceramide-induced TCR up-regulation

DEFF Research Database (Denmark)

Menné, C; Lauritsen, Jens Peter Holst; Dietrich, J

2000-01-01

to increase T cell responsiveness. The purpose of this study was to identify and characterize potential pathways for TCR up-regulation. We found that ceramide affected TCR recycling dynamics and induced TCR up-regulation in a concentration- and time-dependent manner. Experiments applying phosphatase......The TCR is a constitutively recycling receptor meaning that a constant fraction of TCR from the plasma membrane is transported inside the cell at the same time as a constant fraction of TCR from the intracellular pool is transported to the plasma membrane. TCR recycling is affected by protein...... kinase C activity. Thus, an increase in protein kinase C activity affects TCR recycling kinetics leading to a new TCR equilibrium with a reduced level of TCR expressed at the T cell surface. Down-regulation of TCR expression compromises T cell activation. Conversely, TCR up-regulation is expected...

Urea derivatives on the move: cytokinin-like activity and adventitious rooting enhancement depend on chemical structure.

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Ricci, A; Bertoletti, C

2009-05-01

Urea derivatives are synthetic compounds, some of which have proved to be positive regulators of cell division and differentiation. N-phenyl-N'-(2-chloro-4-pyridyl)urea (forchlorofenuron, CPPU) and N-phenyl-N'-(1,2,3-thiadiazol-5-yl)urea (thidiazuron, TDZ), well known urea cytokinin representatives, are extensively used in in vitro plant morphogenesis studies, as they show cytokinin-like activity often exceeding that of adenine compounds. In recent years, renewed interest in structure-activity relationship studies allowed identification of new urea cytokinins and other urea derivatives that specifically enhance adventitious root formation. In this review, we report the research history of urea derivatives, new insights into their biological activity, and recent progress on their mode of action.

Neuropsychiatric manifestations in late-onset urea cycle disorder patients.

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Serrano, Mercedes; Martins, Cecilia; Pérez-Dueñas, Belén; Gómez-López, Lilian; Murgui, Empar; Fons, Carmen; García-Cazorla, Angels; Artuch, Rafael; Jara, Fernando; Arranz, José A; Häberle, Johannes; Briones, Paz; Campistol, Jaume; Pineda, Mercedes; Vilaseca, Maria A

2010-03-01

Inherited urea cycle disorders represent one of the most common groups of inborn errors of metabolism. Late-onset urea cycle disorders caused by partial enzyme deficiencies may present with unexpected clinical phenotypes. We report 9 patients followed up in our hospital presenting late-onset urea cycle disorders who initially manifested neuropsychiatric/neurodevelopmental symptoms (the most prevalent neuropsychiatric/neurodevelopmental diagnoses were mental retardation, attention-deficit hyperactivity disorder [ADHD], language disorder, and delirium). Generally, these clinical pictures did not benefit from pharmacological treatment. Conversely, dietary treatment improved the symptoms. Regarding biochemical data, 2 patients showed normal ammonium but high glutamine levels. This study highlights the fact that neuropsychiatric/neurodevelopmental findings are common among the initial symptomatology of late-onset urea cycle disorders. The authors recommend that unexplained or nonresponsive neuropsychiatric/neurodevelopmental symptoms appearing during childhood or adolescence be followed by a study of ammonia and amino acid plasmatic levels to rule out a urea cycle disorder.

Inborn Errors of Metabolism with Hyperammonemia: Urea Cycle Defects and Related Disorders.

Science.gov (United States)

Summar, Marshall L; Mew, Nicholas Ah

2018-04-01

The urea cycle disorders are a group of inherited biochemical diseases caused by a complete or partial deficiency of any one of the enzymes or transport proteins required to convert toxic ammonia into urea and to produce arginine and citrulline. The clinical manifestations of these disorders are mostly the result of acute or chronic hyperammonemia, which affects the central nervous system. Affected individuals can also develop hepatic dysfunction. These disorders can present at any age from the immediate newborn to later in life. Early diagnosis and treatment are key to improving outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

Urea for long-term treatment of syndrome of inappropriate secretion of antidiuretic hormone.

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Decaux, G; Genette, F

1981-10-24

The efficacy of oral urea in producing a sufficiently high osmotic diuresis was tested in seven patients with the syndrome of inappropriate secretion of antidiuretic hormone. In all patients urea corrected the hyponatraemia despite a normal fluid intake. Five patients were controlled (serum sodium concentration greater than 128 mmol(mEq)/1) with a dose of 30 g urea daily, and two with 60 g daily. The patients who needed 30 g drank 1-2 1 of fluid daily, while those who needed 60 g drank up to 3.1 per day. No major side effects were noted, even after treatment periods of up to 270 days. These findings suggest that urea is a safe and efficacious treatment of the syndrome of inappropriate secretion of antidiuretic hormone.

Effect of dietary nitrogen content and intravenous urea infusion on ruminal and portal-drained visceral extraction of arterial urea in lactating Holstein cows.

Science.gov (United States)

Kristensen, N B; Storm, A C; Larsen, M

2010-06-01

fraction of ammonia released to the ruminal vein is absorbed from an epithelial ammonia pool not in equilibrium with the ventral ruminal ammonia pool. Changing cows from high-N to low-N affected the relative blood urea clearance by kidneys and PDV. The clearance by the kidneys decreased from 41 to 27+/-2 L/h and the clearance by the PDV increased from 52 to 105+/-12 L/h when the diet was changed from high-N to low-N. In conclusion, urea transport across gut epithelia in cattle is adapting to N status and driven by mass action. Data are commensurable with a model for urea transport across gut epithelia based on regulated expression or activity of facilitative urea transporters. 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Correlation between dietary nitrogen, level of plasma urea and urea excretion in urine of buffalo calves

International Nuclear Information System (INIS)

Verma, D.N.; Singh, U.B.

1978-01-01

Two experiments were conducted with 6 male buffalo calves of Murrah breed, aged 1.5 years, to determine whether blood urea nitrogen and urea excretion in urine were associated with protein intake. The animals were fed different amounts of crude protein in their diet. The levels of urea-N in the blood, excretion of 14 C from urea and urea-N in the urine were estimated. Close relationships were observed between nitrogen intake, blood urea nitrogen and urea excretion in the urine. The observations indicated that blood urea-N and urea excretion in urine could be quantitated with the protein intake. (author)

Role of rumen butyrate in regulation of nitrogen utilization and urea nitrogen kinetics in growing sheep.

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Agarwal, U; Hu, Q; Baldwin, R L; Bequette, B J

2015-05-01

Butyrate, a major rumen VFA, has been indirectly linked to enhancement of urea recycling on the basis of increased expression of urea transporter in the rumen epithelia of steers fed a rumen butyrate-enhancing diet. Two studies were conducted to quantify the effect of elevated rumen butyrate concentrations on N balance, urea kinetics and rumen epithelial proliferation. Wether sheep (n= 4), fitted with a rumen cannula, were fed a pelleted ration (∼165 g CP/kg DM, 10.3 MJ ME/kg DM) at 1.8 × ME requirement. In Exp. 1, sheep were infused intraruminally with either an electrolyte buffer solution (Con-Buf) or butyrate dissolved in the buffer solution (But-Buf) during 8-d periods in a balanced crossover design. In Exp. 2, sheep were infused intraruminally with either sodium acetate (Na-Ac) or sodium butyrate (Na-But) for 9 d. All solutions were adjusted to pH 6.8 and 8.0 in Exp. 1 and 2, respectively, and VFA were infused at 10% of ME intake. [15N2] urea was continuously infused intravenously for the last 5 d of each period, and total urine and feces were collected. In Exp. 1, 2H5-phenylalanine was continuously infused intravenously over the last 12 h, after which a biopsy from the rumen papillae was taken for measurement of fractional protein synthesis rate (FSR). Butyrate infusion treatments increased (P = 0.1 in Exp. 1; P urea entry (synthesis) rate was reduced ( urea kinetics were not altered by But-Buf compared with Con-Buf. These studies are the first to directly assess the role of butyrate in urea recycling and its effects on rumen papillae protein turnover in growing lambs. Under the feeding conditions used and the rate of continuous butyrate infusion into the rumen in the present studies, butyrate does not affect overall N retention in growing sheep. However, butyrate may play a role in the redistribution of urea N fluxes in the overall scheme of N metabolism.

Evaluation of acute toxicity of babassu mesocarp in mice

Directory of Open Access Journals (Sweden)

Elizabeth S. B. Barroqueiro

2011-07-01

Full Text Available The safety of babassu mesocarp (Orbignya phalerata Mart., Arecaceae, which exhibited anti-inflammatory and antithrombotic activities, was evaluated by determining the potential acute toxicity in mice. A lyophilized ethanol extract of babassu mesocarp (BME was administered to C3H/HePas mice (10/group in a single dose of 1000, 3000 and 5000 mg/kg, by gavage. General behavior adverse effects and mortality were determined for up to fourteen days. Selected biochemical parameters including glucose, triacylglyceride, cholesterol, urea, alkaline phosphatase and creatinine were determined by colorimetric assay. The heart, liver, spleen, kidneys and brain were weighted and evaluated macro and microscopically. The median lethal dose (LD50 of BME was greater than 5000 mg/kg. No behavior or body weight alterations were detected after the treatment. The acute treatment with BME has no effect on macroscopic and microscopic aspect of examined organs. Instead, BME increased the alkaline phosphatase and reduced the urea concentration in all groups. A significant increase on triacylglyceride was detected in the group BME1000. In conclusion, the acute treatment with high doses of BME can affect some biochemical parameters with a long lasting effect, although any change was detected at tissue level or body and organ weight.

Hydration of urea and alkylated urea derivatives

Science.gov (United States)

Kaatze, Udo

2018-01-01

Compressibility data and broadband dielectric spectra of aqueous solutions of urea and some of its alkylated derivatives have been evaluated to yield their numbers Nh of hydration water molecules per molecule of solute. Nh values in a broad range of solute concentrations are discussed and are compared to hydration numbers of other relevant molecules and organic ions. Consistent with previous results, it is found that urea differs from other solutes in its unusually small hydration number, corresponding to just one third of the estimated number of nearest neighbor molecules. This remarkable hydration behavior is explained by the large density φH of hydrogen bonding abilities offered by the urea molecule. In terms of currently discussed models of reorientational motions and allied dynamics in water and related associating liquids, the large density φH causes a relaxation time close to that of undisturbed water with most parts of water encircling the solute. Therefore only a small part of disturbed ("hydration") water is left around each urea molecule. Adding alkyl groups to the basic molecule leads to Nh values which, within the series of n-alkylurea derivatives, progressively increase with the number of methyl groups per solute. With n-butylurea, Nh from dielectric spectra, in conformity with many other organic solutes, slightly exceeds the number of nearest neighbors. Compared to such Nh values, hydration numbers from compressibility data are substantially smaller, disclosing incorrect assumptions in the formula commonly used to interpret the experimental compressibilities. Similar to other series of organic solutes, effects of isomerization have been found with alkylated urea derivatives, indicating that factors other than the predominating density φH of hydrogen bond abilities contribute also to the hydration properties.

Leaching of dieldrin, permethrin, phenyl urea and 4-CL phenyl urea pesticides from soil

International Nuclear Information System (INIS)

Onal, G.

1978-01-01

Leaching of four 14 C-labelled pesticides (dieldrin, permethrin, phenyl urea and 4-Cl phenyl urea) were investigated. It was found that dieldrin and permethrin were not leached from soil but adsorbed by the soil; phenyl urea and 4-CL phenyl urea were leached to a 7.5 cm depth

Nitrogen metabolism, acid-base regulation, and molecular responses to ammonia and acid infusions in the spiny dogfish shark (Squalus acanthias).

Science.gov (United States)

Nawata, C Michele; Walsh, Patrick J; Wood, Chris M

2015-07-01

Although they are ureotelic, marine elasmobranchs express Rh glycoproteins, putative ammonia channels. To address questions raised by a recent study on high environmental ammonia (HEA) exposure, dogfish were intravascularly infused for 24 h at 3 ml kg(-1) h(-1) with isosmotic NaCl (500 mmol l(-1), control), NH4HCO3 (500 mmol l(-1)), NH4Cl (500 mmol l(-1)), or HCl (as 125 mmol l(-1) HCl + 375 mmol l(-1) NaCl). While NaCl had no effect on arterial acid-base status, NH4HCO3 caused mild alkalosis, NH4Cl caused strong acidosis, and HCl caused lesser acidosis, all predominantly metabolic in nature. Total plasma ammonia (T(Amm)) and excretion rates of ammonia (J(Amm)) and urea-N (J(Urea-N)) were unaffected by NaCl or HCl. However, despite equal loading rates, plasma T(Amm) increased to a greater extent with NH4Cl, while J(Amm) increased to a greater extent with NH4HCO3 due to much greater increases in blood-to-water PNH3 gradients. As with HEA, both treatments caused large (90%) elevations of J(Urea-N), indicating that urea-N synthesis by the ornithine-urea cycle (OUC) is driven primarily by ammonia rather than HCO3(-). Branchial mRNA expressions of Rhbg and Rhp2 were unaffected by NH4HCO3 or NH4Cl, but v-type H(+)-ATPase was down-regulated by both treatments, and Rhbg and Na(+)/H(+) exchanger NHE2 were up-regulated by HCl. In the kidney, Rhbg was unresponsive to all treatments, but Rhp2 was up-regulated by HCl, and the urea transporter UT was up-regulated by HCl and NH4Cl. These responses are discussed in the context of current ideas about branchial, renal, and OUC function in this nitrogen-limited predator.

The excretion of isotope in urea and ammonia for estimating protein turnover in man with [15N]glycine

International Nuclear Information System (INIS)

Fern, E.B.; Garlick, P.J.; McNurlan, M.A.; Waterlow, J.C.

1981-01-01

Four normal adults were given [ 15 N]-glycine in a single dose either orally or intravenously. Rates of whole-body protein turnover were estimated from the excretion of 15 N in ammonia and in urea during the following 9 h. The rate derived from urea took account of the [ 15 N]urea retained in body water. In postabsorptive subjects the rates of protein synthesis given by ammonia were equal to those from urea, when the isotope was given orally, but lower when an intravenous dose was given. In subjects receiving equal portions of food every 2 h rates of synthesis calculated from ammonia were much lower than those from urea whether an oral or intravenous isotope was given. Comparison of rates obtained during the postabsorptive and absorptive periods indicated regulation by food intake primarily of synthesis when measurements were made on urea, but regulation primarily of breakdown when measurements were made on ammonia. These inconsistencies suggest that changes in protein metabolism might be assessed better by correlating results given by different end-products, and it is suggested that the mean value given by urea and ammonia will be useful for this purpose. (author)

Excretion of isotope in urea and ammonia for estimating protein turnover in man with (/sup 15/N)glycine

Energy Technology Data Exchange (ETDEWEB)

Fern, E B; Garlick, P J; McNurlan, M A; Waterlow, J C [London School of Hygiene and Tropical Medicine (UK)

1981-01-01

Four normal adults were given (/sup 15/N)-glycine in a single dose either orally or intravenously. Rates of whole-body protein turnover were estimated from the excretion of /sup 15/N in ammonia and in urea during the following 9 h. The rate derived from urea took account of the (/sup 15/N)urea retained in body water. In postabsorptive subjects the rates of protein synthesis given by ammonia were equal to those from urea, when the isotope was given orally, but lower when an intravenous dose was given. In subjects receiving equal portions of food every 2 h rates of synthesis calculated from ammonia were much lower than those from urea whether an oral or intravenous isotope was given. Comparison of rates obtained during the postabsorptive and absorptive periods indicated regulation by food intake primarily of synthesis when measurements were made on urea, but regulation primarily of breakdown when measurements were made on ammonia. These inconsistencies suggest that changes in protein metabolism might be assessed better by correlating results given by different end-products, and it is suggested that the mean value given by urea and ammonia will be useful for this purpose.

Photoluminescence of urea- and urea/rhodamine B-capped TiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Gonzalo-Juan, I., E-mail: gonzalo@materials.tu-darmstadt.de; Macé, L.; Tengeler, S.; Mosallem, A.; Nicoloso, N.; Riedel, R.

2016-07-01

Urea- and rhodamine B (RhB)-capped TiO{sub 2} nanoparticles (NPs) have been prepared by solvothermal synthesis and characterized by HRTEM, XRD, FTIR, XPS, optical absorption and photoemission. The urea and urea/RhB ligands are capped to the surface of the TiO{sub 2} NPs for the first time through carbamate bonding. The band gap of TiO{sub 2} is slightly reduced from 3.1 eV to 3.0 eV in the urea capped TiO{sub 2} NPs (TU) and 2.9 eV for the NPs capped with urea/RhB (TUR). The generation of new trapping states in TU and TUR at the conduction band edges (surface oxygen vacancies) has been confirmed by the Urbach law providing tail state energies of 180 meV and 270 meV, respectively. These tail states are considered to be responsible for the strong reduction of the photoluminescence at ≈400 nm and the increased emission at ≈600 nm in TU and TUR. The findings suggest that urea- and RhB-capped TiO{sub 2} NPs could have potential applications as photocatalysts, opto-electronic devices, sensors, biological labels and anti-bacterial agents. - Highlights: • Urea- and urea/rhodamine B (RhB)-capped TiO{sub 2} nanoparticles preparation. • Characterization of optical properties of urea- and urea/rhodamine B (RhB)-capped TiO{sub 2} nanoparticles. • The recombination of electrons and holes is significantly reduced in the capped TiO{sub 2} nanoparticles, in comparison with TiO{sub 2}.

Urea recycling in ruminants

International Nuclear Information System (INIS)

Ohara, Yoshiaki; Niibayashi, Tsunekazu

1980-01-01

The transfer of blood urea into the alimentary tract of goats, as ruminants, was studied by the use of 15 N-urea, 15 N-ammonium chloride and physiological experimental techniques. Blood urea after an intravenous injection of 15 N-urea appeared in the first rumen via two routes, the saliva (approximately 60% of the serum urea concentration) and idrect diffusion from the wall of the first rumen, both as the ammonium-form N. The serum urea levels from diets containing different protein levels were paralleled with the protein levels, the ammonium level in the first rumen being similar to that of the serum urea. The transfer of low protein into the NH 3 pool of the first rumen was 56% of the total NH 3 in the entire alimentary tract, and the quantitative ratio of salivary secretion of diffusion in the first rumen was 1:9. The transfer of high protein was 14% in the entire alimentary tract, and the ratio of saliva to diffusion in the first rumen was 6:1. Thus, when protein uptake was large, salivary secretion was the primary route to the first rumen. Approximately 50% of the entire quantity of blood urea in the alimentary tract appeared in the first rumen, and 35%, in the lower alimentary tract, primarily in the duodenum and jejunum. (Chiba, N.)

Modeling of flux, binding and substitution of urea molecules in the urea transporter dvUT.

Science.gov (United States)

Zhang, Hai-Tian; Wang, Zhe; Yu, Tao; Sang, Jian-Ping; Zou, Xian-Wu; Zou, Xiaoqin

2017-09-01

Urea transporters (UTs) are transmembrane proteins that transport urea molecules across cell membranes and play a crucial role in urea excretion and water balance. Modeling the functional characteristics of UTs helps us understand how their structures accomplish the functions at the atomic level, and facilitates future therapeutic design targeting the UTs. This study was based on the crystal structure of Desulfovibrio vulgaris urea transporter (dvUT). To model the binding behavior of urea molecules in dvUT, we constructed a cooperative binding model. To model the substitution of urea by the urea analogue N,N'-dimethylurea (DMU) in dvUT, we calculated the occupation probability of DMU along the urea pore and the ratio of the occupation probabilities of DMU at the external (S ext ) and internal (S int ) binding sites, and we established the mutual substitution rule for binding and substitution of urea and DMU. Based on these calculations and modelings, together with the use of the Monte Carlo (MC) method, we further modeled the urea flux in dvUT, equilibrium urea binding to dvUT, and the substitution of urea by DMU in the dvUT. Our modeling results are in good agreement with the existing experimental functional data. Furthermore, the modelings have discovered the microscopic process and mechanisms of those functional characteristics. The methods and the results would help our future understanding of the underlying mechanisms of the diseases associated with impaired UT functions and rational drug design for the treatment of these diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Substitution of lucerne hay by untreated, urea-enriched and urea ...

African Journals Online (AJOL)

Wheat straw was left untreated (WS), enriched with 1.5% urea (UWS), or ammoniated with 5.5% urea in a stack for 8 .... nitrogen concentration for maximal microbial synthesis is in ... faeces and urine samples were taken daily and pooled for.

A Role for Cytosolic Fumarate Hydratase in Urea Cycle Metabolism and Renal Neoplasia

Directory of Open Access Journals (Sweden)

Julie Adam

2013-05-01

Full Text Available The identification of mutated metabolic enzymes in hereditary cancer syndromes has established a direct link between metabolic dysregulation and cancer. Mutations in the Krebs cycle enzyme, fumarate hydratase (FH, predispose affected individuals to leiomyomas, renal cysts, and cancers, though the respective pathogenic roles of mitochondrial and cytosolic FH isoforms remain undefined. On the basis of comprehensive metabolomic analyses, we demonstrate that FH1-deficient cells and tissues exhibit defects in the urea cycle/arginine metabolism. Remarkably, transgenic re-expression of cytosolic FH ameliorated both renal cyst development and urea cycle defects associated with renal-specific FH1 deletion in mice. Furthermore, acute arginine depletion significantly reduced the viability of FH1-deficient cells in comparison to controls. Our findings highlight the importance of extramitochondrial metabolic pathways in FH-associated oncogenesis and the urea cycle/arginine metabolism as a potential therapeutic target.

Effect of Urea on G-Quadruplex Stability.

Science.gov (United States)

Aslanyan, Lusine; Ko, Jordan; Kim, Byul G; Vardanyan, Ishkhan; Dalyan, Yeva B; Chalikian, Tigran V

2017-07-13

G-quadruplexes represent a class of noncanonical nucleic acid structures implicated in transcriptional regulation, cellular function, and disease. An understanding of the forces involved in stabilization and destabilization of the G-quadruplex conformation relative to the duplex or single-stranded conformation is a key to elucidating the biological role of G-quadruplex-based genomic switches and the quest for therapeutic means for controlled induction or suppression of a G-quadruplex at selected genomic loci. Solute-solvent interactions provide a ubiquitous and, in many cases, the determining thermodynamic force in maintaining and modulating the stability of nucleic acids. These interactions involve water as well as water-soluble cosolvents that may be present in the solution or in the crowded environment in the cell. We present here the first quantitative investigation of the effect of urea, a destabilizing cosolvent, on the conformational preferences of a G-quadruplex formed by the telomeric d[A(G 3 T 2 A) 3 G 3 ] sequence (Tel22). At 20 mM NaCl and room temperature, Tel22 undergoes a two-state urea-induced unfolding transition. An increase in salt mitigates the deleterious effect of urea on Tel22. The urea m-value of Tel22 normalized per change in solvent-accessible surface area, ΔS A , is similar to those for other DNA and RNA structures while being several-fold larger than that of proteins. Our results suggest that urea can be employed as an analytical tool in thermodynamic characterizations of G-quadruplexes in a manner similar to the use of urea in protein studies. We emphasize the need for further studies involving a larger selection of G-quadruplexes varying in sequence, topology (parallel, antiparallel, hybrid), and molecularity (monomolecular, bimolecular, tetramolecular) to outline the advantages and the limits of the use of urea in G-quadruplex studies. A deeper understanding of the effect of solvent and cosolvents on the differential stability of the

Current Knowledge on the Acute Regulation of Steroidogenesis.

Science.gov (United States)

Selvaraj, Vimal; Stocco, Douglas M; Clark, Barbara J

2018-04-27

How rapid induction of steroid hormone biosynthesis occurs in response to trophic hormone stimulation of steroidogenic cells has been a subject of intensive investigation for approximately six decades. A key observation made very early was that acute regulation of steroid biosynthesis required swift and timely synthesis of a new protein whose role appeared to be involved in the delivery of the substrate for all steroid hormones, cholesterol, from the outer to the inner mitochondrial membrane where the process of steroidogenesis begins. It was quickly learned that this transfer of cholesterol to the inner mitochondrial membrane was the regulated and rate limiting step in steroidogenesis. Following this observation, the quest for this putative regulator protein(s) began in earnest in the late 1950s. This review provides a history of this quest, the candidate proteins that arose over the years, and facts surrounding their rise or decline. Only two have persisted-Translocator Protein (TSPO) and the Steroidogenic Acute Regulatory Protein (StAR). We present a detailed summary of the work that has been published for each of these two proteins, the specific data that has appeared in support of their role in cholesterol transport and steroidogenesis, and the ensuing observations that have arisen in recent years that have refuted the role of TSPO in this process. We believe that the only viable candidate that has been shown to be indispensable is the StAR protein. Lastly, we provide our view on what may be the most important questions concerning the acute regulation of steroidogenesis that need to be asked in future.

Urea metabolism in cattle and buffaloes fed diets containing NPN salts, usin g urea radiotracers

International Nuclear Information System (INIS)

Dhiman, T.R.; Arora, S.P.

1990-01-01

Urea metabolism studies were conducted using isotope dilution techniques. Animals in groups 1 and 3 were fed basal diet (S, 0.11%) supplemented with urea (test diet 1) and those of groups 2 and 4 supplemented urea plus ammonium sulphate (test diet 2) containing 0.22% S. A single injection of a mixture of 15 N-urea and 14 C-urea was given intravenously and 51 Cr-EDTA was given as a single infusion intraruminally. The pattern of release of ammonia, mean ruminal ammonia, plasma urea, rumen fluid outflow rate, rumen ammonia pool size and ammonia outflow from rumen remained unaffected due to different dietary treatments. On an average, 73.3% of plasma urea synthesized was excreted in urine with test diet 1 and showing 26.6% degradation in the gastrointestinal tract, whereas 68.8% was excreted with test diet 2 and showing 31.3% degradation in the gastrointestinal tract. At 24 hr, 18.33 to 20.93% of nitrogen entering the ruminal ammonia pool was derived from plasma urea in calves of groups 1 and 2 and 24.22 to 27.49 in buffalo calves of groups 3 and 4 respectively. Sulphur supplementation through ammonium sulphate (N : S, 10 :1) resulted in better utilization of nitrogen with test diet 2 by lowering urea excretion rate and increasing urea recycling rate in both the species. (author). 5 tabs., 16 refs

Metabolism of urea in kids fed different levels of urea molasses diets

International Nuclear Information System (INIS)

Lal, M.; Singh, U.B.; Verma, D.N.

1981-01-01

Urea entry rates were measured in the body pool of Barbari kids using a single injection isotope dilution technique. The kids were divided into five groups (T 1 , T 2 , T 3 , T 4 and T 5 ) and they were fed different levels of urea molasses viz., 10, 25, 35, 40 and 0 percent to meet their DCP requirement along with concentrate mixture and oat hay as per A.R.C. recommendation. Urea entry rate was significantly higher (P 1 and the control group (T 5 without urea in their diets) than that of T 2 , T 3 and T 4 which were not significantly different from each other. (author)

Hydrogen bonding of formamide, urea, urea monoxide and their thio

Indian Academy of Sciences (India)

Ab initio and DFT methods have been employed to study the hydrogen bonding ability of formamide, urea, urea monoxide, thioformamide, thiourea and thiourea monoxide with one water molecule and the homodimers of the selected molecules. The stabilization energies associated with themonohydrated adducts and ...

Understanding Strategy of Nitrate and Urea Assimilation in a Chinese Strain of Aureococcus anophagefferens through RNA-Seq Analysis

Science.gov (United States)

Dong, Hong-Po; Huang, Kai-Xuan; Wang, Hua-Long; Lu, Song-Hui; Cen, Jing-Yi; Dong, Yue-Lei

2014-01-01

Aureococcus anophagefferens is a harmful alga that dominates plankton communities during brown tides in North America, Africa, and Asia. Here, RNA-seq technology was used to profile the transcriptome of a Chinese strain of A. anophagefferens that was grown on urea, nitrate, and a mixture of urea and nitrate, and that was under N-replete, limited and recovery conditions to understand the molecular mechanisms that underlie nitrate and urea utilization. The number of differentially expressed genes between urea-grown and mixture N-grown cells were much less than those between urea-grown and nitrate-grown cells. Compared with nitrate-grown cells, mixture N-grown cells contained much lower levels of transcripts encoding proteins that are involved in nitrate transport and assimilation. Together with profiles of nutrient changes in media, these results suggest that A. anophagefferens primarily feeds on urea instead of nitrate when urea and nitrate co-exist. Furthermore, we noted that transcripts upregulated by nitrate and N-limitation included those encoding proteins involved in amino acid and nucleotide transport, degradation of amides and cyanates, and nitrate assimilation pathway. The data suggest that A. anophagefferens possesses an ability to utilize a variety of dissolved organic nitrogen. Moreover, transcripts for synthesis of proteins, glutamate-derived amino acids, spermines and sterols were upregulated by urea. Transcripts encoding key enzymes that are involved in the ornithine-urea and TCA cycles were differentially regulated by urea and nitrogen concentration, which suggests that the OUC may be linked to the TCA cycle and involved in reallocation of intracellular carbon and nitrogen. These genes regulated by urea may be crucial for the rapid proliferation of A. anophagefferens when urea is provided as the N source. PMID:25338000

ASOTHEMIA EFFECT UPON THE LIVER ARGINASE ACTIVITY IN THE ACUTE KIDNEY DAMAGE

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Jelena Djordjevic

2002-07-01

Full Text Available The acute damage of the kidney function leads to an outstanding disbalance of many homeostatic mechanisms in the organism that emerges as a consequence of the reduced glomerulic filtration and the accompanying oliguria. This conditions the emergence of asothemia, that is, the state caracterized by an increase of the level of urea, creatinine and other ureic toxins in the blood. The results of the previous exami-nations show that the acute renal insufficiency is a disturbance accompanied with ac-celerated protein catabolism. The urea is a terminal product of the protein catabolism whose synthesis is mainly taking place in the liver; that is why the research aimed at examining the liver arginase activity, terminal enzyme in the urea synthesis cycle in various experimental models of the acute renal insufficiency. The acute asothemia is experimentally caused upon the male Spraque Dawlly rats by means of two models, namely, the model of bilateral binding of the urethra (BPU and the clycerolic model. The arginase activity in the liver tissue homogenate is measured by the Porembsky and Cedra method on the basis of the liberated ornithine liberation. In the plasma of the experimental animals the level of urea and creatinine was measured for the sake of estimating the renal function. In both the models of the acute kidney damage there was a considerable increase of the urea and creatinine concentration in the plasma (p<0,001 which is followed by a significant increase of the hepatic arginase activity with respect to the control group of the animals. On the basis of the obtained results it can be conclude that asothemia in the acute renal insufficiency is followed by an in-crease in the liver arginase activity.

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

Science.gov (United States)

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

2015-01-01

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

Phosphorus-32 in polycythemia vera with and without maintenance treatment. Intermediate follow-up results

International Nuclear Information System (INIS)

Najean, Y.; Rain, J.D.

1995-01-01

Three-hundred and seventy-two patients with polycythemia vera, aged 65 years or more or with a high risk of vascular complications, were openly treated between 1979 and 1994 with 32 P or a combination of 32 P plus a small maintenance dose (7,5 mg/kg/day) of hydroxy urea. Although only a small number of patients was followed long enough to allow definite conclusions, some results are already significant in this intermediary study performed in November 1994. Maintenance treatment with hydroxy urea led to a significant prolongation of the intervals between 32 P administrations and to a decreased annual mean dose of radiophosphorus. Median survival does not differ between to the two treatment groups, 10,7 years compared to 10,0 years. The rate of vascular complications did not differ between groups. At 10 years follow-up, the risk of developing (epithelial) cancer was increased in the group of patients who received maintenance treatment, 30% compared to 10%. Similarly, development of myelodysplasia, acute leukemia or lymphoma was more common in patients receiving hydroxy urea, 25% compared to 12%. Myeloid transformation of the spleen occurred with the same frequency. Our intermediate follow-up results show that addition of hydroxy urea to 32 P treatment does not change survival or vascular complications in polycythemia vera patients, but probably increases the risk of developing cancer or leukemia. (authors). 2 refs., 4 figs

Slow release coating remedy for nitrogen loss from conventional urea: a review.

Science.gov (United States)

Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar

2016-03-10

Developing countries are consuming major part of the global urea production with an anticipated nitrogen use efficiency of 20 to 35%. The release of excess nitrogen in the soil is not only detrimental to the environment but also lessens the efficiency of the conventional urea. The urea performance can be enhanced by encapsulating it with slow release coating materials and synchronizing the nutrients' release with the plant up-taking. However, the present cost of most of the coated fertilizers is considerably higher than the conventional fertilizers. The high cost factor prevents their widespread use in mainstream agriculture. This paper documents a review of literature related to the global urea market, issues pertaining to the conventional urea use, natural and synthetic materials for slow release urea and fluidized bed spray coating process. The aim of the current review is to develop technical understanding of the conventional and non-conventional coating materials and associated spray coating mechanism for slow release urea production. The study also investigated the potential of starch as the coating material in relation to the coatings tested previously for controlled release fertilizers. Copyright © 2016 Elsevier B.V. All rights reserved.

Urea cycle disorder misdiagnosed as multiple sclerosis: a case report and review of the literature.

Science.gov (United States)

Algahtani, Hussein; Alameer, Seham; Marzouk, Yousef; Shirah, Bader

2018-04-01

Urea cycle disorders are a group of inborn errors of metabolism caused by dysfunction of any of the six enzymes or two transport proteins involved in urea biosynthesis. In this paper, we report a patient who presented with neurological dysfunction and coma in the immediate postpartum period. She was misdiagnosed for many years as a case of multiple sclerosis. The importance of reporting this case is to illustrate that the wrong diagnosis of patients as being affected with multiple sclerosis for many years due to magnetic resonance imaging abnormalities rather than the classic relapsing-remitting nature of the disease may lead to catastrophic consequences. The patient was treated with intravenous steroids several times, which is contraindicated in patients with urea cycle disorders as it may precipitate acute hyperammonemic attacks. In addition, the management of urea cycle disorder could have started earlier and avoided multiple admissions to the intensive care unit. We believe that the presence of symmetric hyperintense insular cortical changes are seen in multiple hyperammonemic processes, and in the context of the clinical presentation and high ammonia levels can be suggestive of a urea cycle disorder. For any patient presenting with atypical clinical features, images should be reviewed and discussed in detail with an experienced neuroradiologist. In addition, the ammonia levels should be checked if a urea cycle disorder is suspected.

Influence of milk urea concentration on fractional urea disappearance rate from milk to blood plasma in dairy cows.

Science.gov (United States)

Spek, J W; Dijkstra, J; Bannink, A

2016-05-01

The relationship between milk urea nitrogen (MUN; mg of N/dL) and urinary N excretion is affected, among others, by diurnal dynamics in MUN, which in turn is largely influenced by feed intake pattern and characteristics of urea transfer from blood plasma to milk and vice versa. This study aimed to obtain insight in urea transfer characteristics within the mammary gland and from the mammary gland to blood plasma in dairy cows at various concentrations of plasma urea nitrogen (PUN; mg of N/dL) and MUN. Urea transfer from milk to blood plasma and urea transfer within the mammary gland itself was evaluated in a 4×4 Latin square design using 4 lactating multiparous Holstein-Friesian cows (milk production of 39.8±4.70kg/d and 90±3.9 d in milk). Treatments consisted of 4 primed continuous intravenous urea infusions of 0, 5, 10, and 15g of urea/h. Boluses of [(15)N(15)N]urea were injected in cistern milk at 20, 60, and 100 min before the 1700h milking. Milk was collected in portions of approximately 2 L at the 1700h milking. Milk samples were analyzed for urea and enrichment of (15)N-urea. Results from one cow were discarded because of leakage of milk from the teats after injection of boluses of [(15)N(15)N]urea. Increasing urea infusion rate linearly increased PUN from 11.4 (0g of urea/h) to 25.9mg/dL (15g of urea/h) and MUN from 10.3 (0g of urea/h) to 23.5 (15g of urea/h) mg of N/dL. The percentage of injected [(15)N(15)N]urea recovered from milk at the time of injection was not affected by urea infusion rate and varied between 65.1 and 73.0%, indicating that a substantial portion of injected [(15)N(15)N]urea was not accounted for by collected milk. The estimated fractional disappearance rate of (15)N-urea from milk to blood (Kurea; per hour) linearly increased from 0.429 (0g of urea/h) to 0.641 per hour (15g of urea/h). Cistern injected [(15)N(15)N]urea diffused within 20 min after injection toward alveoli milk. Calculations with the average Kurea estimated in this

Polymer Coated Urea in Turfgrass Maintains Vigor and Mitigates Nitrogen's Environmental Impacts.

Directory of Open Access Journals (Sweden)

Joshua J LeMonte

Full Text Available Polymer coated urea (PCU is a N fertilizer which, when added to moist soil, uses temperature-controlled diffusion to regulate N release in matching plant demand and mitigate environmental losses. Uncoated urea and PCU were compared for their effects on gaseous (N2O and NH3 and aqueous (NO3(- N environmental losses in cool season turfgrass over the entire PCU N-release period. Field studies were conducted on established turfgrass sites with mixtures of Kentucky bluegrass (Poa pratensis L. and perennial ryegrass (Lolium perenne L. in sand and loam soils. Each study compared 0 kg N ha(-1 (control to 200 kg N ha(-1 applied as either urea or PCU (Duration 45CR®. Application of urea resulted in 127-476% more evolution of measured N2O into the atmosphere, whereas PCU was similar to background emission levels from the control. Compared to urea, PCU reduced NH3 emissions by 41-49% and N2O emissions by 45-73%, while improving growth and verdure compared to the control. Differences in leachate NO3(- among urea, PCU and control were inconclusive. This improvement in N management to ameliorate atmospheric losses of N using PCU will contribute to conserving natural resources and mitigating environmental impacts of N fertilization in turfgrass.

Urea cycle disorders: a case report of a successful treatment with liver transplant and a literature review.

Science.gov (United States)

Foschi, Francesco Giuseppe; Morelli, Maria Cristina; Savini, Sara; Dall'Aglio, Anna Chiara; Lanzi, Arianna; Cescon, Matteo; Ercolani, Giorgio; Cucchetti, Alessandro; Pinna, Antonio Daniele; Stefanini, Giuseppe Francesco

2015-04-07

The urea cycle is the final pathway for nitrogen metabolism. Urea cycle disorders (UCDs) include a variety of genetic defects, which lead to inefficient urea synthesis. Elevated blood ammonium level is usually dominant in the clinical pattern and the primary manifestations affect the central nervous system. Herein, we report the case of a 17-year-old girl who was diagnosed with UCD at the age of 3. Despite a controlled diet, she was hospitalized several times for acute attacks with recurrent life risk. She came to our attention for a hyperammonemic episode. We proposed an orthotopic liver transplant (OLT) as a treatment; the patient and her family were in complete agreement. On February 28, 2007, she successfully received a transplant. Following the surgery, she has remained well, and she is currently leading a normal life. Usually for UCDs diet plays the primary therapeutic role, while OLT is often considered as a last resort. Our case report and the recent literature data on the quality of life and prognosis of traditionally treated patients vs OLT patients, support OLT as a primary intervention to prevent life-threatening acute episodes and chronic mental impairment.

In vivo urea cycle flux distinguishes and correlates with phenotypic severity in disorders of the urea cycle

Science.gov (United States)

Lee, Brendan; Yu, Hong; Jahoor, Farook; O'Brien, William; Beaudet, Arthur L.; Reeds, Peter

2000-01-01

Urea cycle disorders are a group of inborn errors of hepatic metabolism that result in often life-threatening hyperammonemia and hyperglutaminemia. Clinical and laboratory diagnosis of partial deficiencies during asymptomatic periods is difficult, and correlation of phenotypic severity with either genotype and/or in vitro enzyme activity is often imprecise. We hypothesized that stable isotopically determined in vivo rates of total body urea synthesis and urea cycle-specific nitrogen flux would correlate with both phenotypic severity and carrier status in patients with a variety of different enzymatic deficiencies of the urea cycle. We studied control subjects, patients, and their relatives with different enzymatic deficiencies affecting the urea cycle while consuming a low protein diet. On a separate occasion the subjects either received a higher protein intake or were treated with an alternative route medication sodium phenylacetate/benzoate (Ucephan), or oral arginine supplementation. Total urea synthesis from all nitrogen sources was determined from [18O]urea labeling, and the utilization of peripheral nitrogen was estimated from the relative isotopic enrichments of [15N]urea and [15N]glutamine during i.v. co-infusions of [5-(amide)15N]glutamine and [18O]urea. The ratio of the isotopic enrichments of 15N-urea/15N-glutamine distinguished normal control subjects (ratio = 0.42 ± 0.06) from urea cycle patients with late (0.17 ± 0.03) and neonatal (0.003 ± 0.007) presentations irrespective of enzymatic deficiency. This index of urea cycle activity also distinguished asymptomatic heterozygous carriers of argininosuccinate synthetase deficiency (0.22 ± 0.03), argininosuccinate lyase deficiency (0.35 ± 0.11), and partial ornithine transcarbamylase deficiency (0.26 ± 0.06) from normal controls. Administration of Ucephan lowered, and arginine increased, urea synthesis to the degree predicted from their respective rates of metabolism. The 15N-urea/15N-glutamine ratio

Standardization of the TRUE Test imidazolidinyl urea and diazolidinyl urea patches

DEFF Research Database (Denmark)

Agner, T; Andersen, Klaus Ejner; Björkner, B

2001-01-01

The preservatives imidazolidinyl urea (IMID, Germall 115) and diazolidinyl urea (DU, Germall II) are commonly used in cosmetic products and are well-known sensitizers. The aim of the present study was to establish the optimal patch test concentration in hydrophilic dried-in vehicle (TRUE Test...

Urea recycling from the renal pelvis in sheep: A study with [14C]urea

International Nuclear Information System (INIS)

Cirio, A.; Boivin, R.

1990-01-01

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

Isotopic studies of urea metabolism in rabbits

Science.gov (United States)

Regoeczi, E.; Irons, L.; Koj, A.; McFarlane, A. S.

1965-01-01

1. The half-life of [15N]urea was found to be significantly longer than that of [14C]urea injected at the same time, the differences being due to endogenous catabolism of urea, which is accompanied by little or no reutilization of 14C but is approx. 20% for 15N. [15N]Urea therefore appears to be valueless as an indicator of nitrogen metabolism unless the extents of endogenous catabolism of urea and of fractional reutilization of 15N can be separately estimated. 2. Though measurements of the radioactivity of expired 14CO2 confirmed the existence of considerable urea catabolism these could not be used for quantitative assessments. 3. Alternative graphical methods based on [14C]urea specific activities in plasma and urine samples were used to calculate the fraction of urea production that is excreted. Values by the two methods were in good agreement and showed that some animals excrete less than half the urea that they produce. 4. Specific activity differences between simultaneous samples of urinary and plasma urea reflect the presence of a pool of urea in the kidney that is not in equilibrium with the body urea pool. Calculations indicate the presence of urea in the kidney that in some cases may represent as much as 15% of the body pool, and in two animals in which post-mortem renal analyses were performed the masses of urea found agreed closely with the calculated values. 5. A model for urea metabolism is proposed that includes this pool in the excretory pathway. The related theory is shown to be adequate to explain the shape of the specific activity curves of urinary urea from the time of injection and the constant delay of the specific activity of urinary urea, relative to that of plasma urea, that is observed after a short preliminary equilibration period. 6. The body urea pool was calculated from the activity retained at 1·5hr. by excluding renal activity and the corrected specific activity of plasma urea at the same time. The urea pool was calculated to be

The role of nickel in urea assimilation by algae.

Science.gov (United States)

Rees, T A; Bekheet, I A

1982-12-01

Nickel is required for urease synthesis by Phaeodactylum tricornutum and Tetraselmis subcordiformis and for growth on urea by Phaeodactylum. There is no requirement for nickel for urea amidolyase synthesis by Chlorella fusca var. vacuolata. Neither copper nor palladium can substitute for nickel but cobalt partially restored urease activity in Phaeodactylum. The addition of nickel to nickel-deficient cultures of Phaeodactylum or Tetraselmis resulted in a rapid increase of urease activity to 7-30 times the normal level; this increase was not inhibited by cycloheximide. It is concluded that nickel-deficient cells over-produce a non-functional urease protein and that either nickel or the functional urease enzyme participates in the regulation of the production of urease protein.

Utilization of dietary urea in rainbow trout.

Science.gov (United States)

Kaushik, S J; Dabrowski, K R; Dabrowska, H; Olah, E; Luquet, P

1983-01-01

Experiments were conducted to examine the potential utilization of dietary urea by rainbow trout. A control diet and two diets supplemented with 1 and 3% of urea were fed to fish. Postprandial levels of urea and ammonia in blood plasma, and postprandial excretion of these metabolites were followed during 24 h. Apparent digestibility of urea in rainbow trout was very high (greater than 98%). Maximum values of urea levels in plasma were reached 6 h (32.3 +/- 10.2 micrograms/ml) after a meal in the control fish and respectively 6 h (83.4 +/- 18.4 micrograms/ml) and 8 h (250.3 +/- 96.1 micrograms/ml) after a meal in trout fed 1 and 3% urea diets. Peaks of urea excretion rates appeared 7-9 h after meal, coinciding with the highest circulating urea concentration. Total daily urea excretion amounted to 5.53, 10.43 and 33.80 mg urea N/100 mg N intake in trout fed the control, 1 and 3% urea diets, respectively. It is concluded that the dietary urea is readily absorbed in the digestive tract of trout but is totally excreted thus leading to no beneficial effect on nitrogen balance. This excretion of urea also takes place passively without any increase in energy demands.

Measurement of urea kinetics in vivo by means of a constant tracer infusion of di-15N-urea

International Nuclear Information System (INIS)

Wolfe, R.R.

1981-01-01

We have assessed the feasibility of studying urea metabolism in vivo in both steady state and nonsteady state situations by means of the primed constant infusion of di-15N-urea and the analysis of the resulting enrichment in plasma urea. Both hepatectomized dogs with known rates of urea infusion and intact dogs were studied. The enrichment of the bistrimethylsilyl derivative of urea was determined on a gas chromatograph-mass spectrometer. Selected ion monitoring was set for m/e 189 (M - 15), m/e 190 (A + 1), and m/e 191 (A + 2), thus enabling the calculation of the rate of urea production from nonrecycled NH3 (from A + 2 data) (Ra N), the rate of recycling of NH3 into urea (Ra R) (from A + 1 data), and thus the total rate of urea production (Ra N + Ra R). When urine collections were made, the incorporation of urea-N into protein was estimated from the difference between Ra N and urea excretion. We found that, in the steady state in a hepatectomized dog, the rate of appearance of urea can be determined accurately. In the nonsteady state in both hepatectomized and intact dogs, urea appearance could be estimated within +/- 20% in most situations. The only situation in which this was not the case was when we attempted to measure rapid changes in Ra R. Thus, within limits, this can be a useful technique enabling the quantitation of various aspects of urea metabolism

Greener on the Other Side: How Increased Urea Use may Promote Cyanobacterial Blooms

Science.gov (United States)

Erratt, K. J.; Creed, I. F.; Trick, C. G.

2017-12-01

The frequency of freshwater cyanobacterial blooms is on the rise in temperate regions around the world. The widespread use of chemical fertilizers linked to modern agricultural practices has enhanced the fertility of surface waters promoting the expansion of cyanobacteria dominated harmful algal blooms. While phosphorus (P) has been recognized as the principal agent regulating phytoplankton productivity in inland waters, elevated P is not the universal trigger for bloom initiation. P fertilizer applications across the globe have been outpaced by nitrogen (N) fertilizer use. Not only has the load of N entering surface waters increased, but its chemical composition has been altered. The use of inorganic-N fertilizers has been waned in favor of urea-based products, with urea now accounting for more than half of total N-fertilizer applications worldwide. This contemporary shift in fertilizer usage has coincided with the rise of cyanobacteria dominated harmful algal blooms in freshwaters. Here, we examined the relative success of urea as a N-source relative to inorganic N forms (NO3-, NH4+) for three common bloom-forming species of cyanobacteria: Microcystis aeruginosa, Dolichospermum flos-aque, and Synechococcus sp. We found that (1) urea was consistently drawdown more rapidly relative to inorganic N substrates, suggesting that cyanobacteria exhibit a preference for urea over inorganic N forms; (2) cyanobacteria consume urea in excess of cellular requirements; and (3) urea may offer cyanobacteria a competitive edge over eukaryotic algae by enhancing light absorption capabilities. As we push forward into the 21st century, our reliance on urea-based fertilizers is projected to escalate and it is critical that we understand the unintended consequences urea discharge could be having on receiving freshwaters.

The effect of conditioning agents on the corrosive properties of molten urea

Energy Technology Data Exchange (ETDEWEB)

Nichols, D E; Nguyen, D T; Norton, M M; Parker, B R; Daniels, L E

1991-01-01

From the process case histories of the failure of several heat exchanger tube bundles, it was revealed that molten urea containing lignosulfonate as a granulation conditioning-hardening agent (Urea LS[trademark]) is corrosive to Types 304 and 316 stainless steel. The results of field and laboratory immersion corrosion tests indicated that the corrosivity of molten urea is strongly dependent on the process temperature rather than the conditioner composition. At temperatures below 295F, molten Urea LS[trademark] is not aggressive to these stainless steels. However, at temperatures above 300F, the corrosion of these stainless steels is extremely severe. The corrosion rate of Types 304, 304L, 316, and 316L is as high as hundreds of mils per year. The corrosion mechanism tends to be more general than localized. The results of the laboratory corrosion test also revealed that among alloying elements, copper is detrimental to corrosion resistance of stainless steel exposed to molten Urea LS[trademark], chromium is the most beneficial, and nickel has only a minor effect. Thus, copper-free and chromium stainless steels have superior corrosion resistance to the molten Urea LS[trademark] at a wide range of temperatures up to 345F.

Acute up-regulation of the rat brain somatostatin receptor-effector system by leptin is related to activation of insulin signaling and may counteract central leptin actions.

Science.gov (United States)

Perianes-Cachero, A; Burgos-Ramos, E; Puebla-Jiménez, L; Canelles, S; Frago, L M; Hervás-Aguilar, A; de Frutos, S; Toledo-Lobo, M V; Mela, V; Viveros, M P; Argente, J; Chowen, J A; Arilla-Ferreiro, E; Barrios, V

2013-11-12

Leptin and somatostatin (SRIF) have opposite effects on food seeking and ingestive behaviors, functions partially regulated by the frontoparietal cortex and hippocampus. Although it is known that the acute suppression of food intake mediated by leptin decreases with time, the counter-regulatory mechanisms remain unclear. Our aims were to analyze the effect of acute central leptin infusion on the SRIF receptor-effector system in these areas and the implication of related intracellular signaling mechanisms in this response. We studied 20 adult male Wister rats including controls and those treated intracerebroventricularly with a single dose of 5 μg of leptin and sacrificed 1 or 6h later. Density of SRIF receptors was unchanged at 1h, whereas leptin increased the density of SRIF receptors at 6h, which was correlated with an elevated capacity of SRIF to inhibit forskolin-stimulated adenylyl cyclase activity in both areas. The functional capacity of SRIF receptors was unaltered as cell membrane levels of αi1 and αi2 subunits of G inhibitory proteins were unaffected in both brain areas. The increased density of SRIF receptors was due to enhanced SRIF receptor subtype 2 (sst2) protein levels that correlated with higher mRNA levels for this receptor. These changes in sst2 mRNA levels were concomitant with increased activation of the insulin signaling, c-Jun and cyclic AMP response element-binding protein (CREB); however, activation of signal transducer and activator of transcription 3 was reduced in the cortex and unchanged in the hippocampus and suppressor of cytokine signaling 3 remained unchanged in these areas. In addition, the leptin antagonist L39A/D40A/F41A blocked the leptin-induced changes in SRIF receptors, leptin signaling and CREB activation. In conclusion, increased activation of insulin signaling after leptin infusion is related to acute up-regulation of the SRIF receptor-effector system that may antagonize short-term leptin actions in the rat brain

Effect of nitrogen supplementation on urea kinetics and microbial use of recycled urea in steers consuming corn-based diets.

Science.gov (United States)

Brake, D W; Titgemeyer, E C; Jones, M L; Anderson, D E

2010-08-01

We studied the effects of supplementing N as distillers dried grains with solubles (DDGS) or urea to steers consuming corn-based diets. Six ruminally and duodenally cannulated steers (244 kg) were used in 2 concurrent 3 x 3 Latin squares and fed 1 of 3 corn-based diets: control (10.2% CP), urea (13.3% CP), or DDGS (14.9% CP). Periods were 14 d, with 9 d for adaptation and 5 d for collection of urine and feces. Urinary (15)N(15)N-urea enrichments, resulting from venous infusions of (15)N(15)N-urea, were used to measure urea kinetics. Dry matter intake (6.0 kg/d) was not affected by treatment, but N intake differed (99, 151, and 123 g/d for the control, DDGS, and urea treatments, respectively). Urea-N synthesis tended to be greater (P = 0.09) for DDGS (118 g/d) than for the control treatment (52 g/d), with the urea treatment (86 g/d) being intermediate. Urea-N excreted in the urine was greater (P urea treatments (29 g/d) than for the control treatment (13 g/d). Gastrointestinal entry of urea-N was not statistically different among treatments (P = 0.25), but was numerically greatest for DDGS (83 g/d), intermediate for urea (57 g/d), and least for the control (39 g/d). The amount of urea-N returned to the ornithine cycle tended to be greater (P = 0.09) for the DDGS treatment (47 g/d) than for the urea (27 g/d) or control treatment (16 g/d). The fraction of recycled urea-N that was apparently used for anabolism tended (P = 0.14) to be greater for the control treatment (0.56) than for the DDGS treatment (0.31), with the urea treatment (0.45) being intermediate, but no differences were observed among treatments in the amount of urea-N used for anabolism (P = 0.66). Urea kinetics in cattle fed grain-based diets were largely related to the amount of N consumed. The percentage of urea production that was captured by ruminal bacteria was greater (P urea treatment (22%), but the percentage of duodenal microbial N flow that was derived from recycled urea-N tended (P = 0.10) to

The elevated serum urea:creatinine ratio in canine babesiosis in South Africa is not of renal origin.

Science.gov (United States)

de Scally, M P; Leisewitz, A L; Lobetti, R G; Thompson, P N

2006-12-01

Pigmented serum, usually due to free haemoglobin and/or bilirubin, is a common finding in dogs with babesiosis, resulting in interference with all biochemical tests that rely on photochemistry. This is particularly true of urea and creatinine determinations, complicating the diagnosis of acute renal failure, which is a serious complication of babesiosis. A disproportionately raised serum urea concentration of unknown origin occurs in severely anaemic canine babesiosis patients and gives rise to an increased serum urea:creatinine ratio. The assay for cystatin-C, an excellent measure of glomerular filtration rate, is unaffected by free serum haemoglobin, and due to its different intrinsic origins, is free of influence by the metabolic derangements and organ pathology, other than renal disease, encountered in canine babesiosis. Serum cystatin-C was used to compare the concentrations of serum urea and serum creatinine in dogs with the severely anaemic form of canine babesiosis as well as a canine babesiosis-free reference group. Mean serum urea and mean serum urea:creatinine ratio were significantly elevated in the babesia-infected group relative to the reference population in this study. Mean serum creatinine and mean serum cystatin-C were within the reference ranges. Therefore an elevated urea:creatinine ratio in canine babesiosis in the presence of a normal serum creatinine concentration is considered to be caused by an elevated serum urea concentration and is most likely of non-renal origin. Serum creatinine was therefore as specific a measure of renal function as serum cystatin-C in canine babesiosis in this study. The sensitivity of serum creatinine as a measure of renal function was not established by this study. Serum urea, however, proved to be of little use compared to serum cystatin-C and serum creatinine. Serum urea should therefore not be used to diagnose renal failure in canine babesiosis.

Follow up of acute gonococcal urethritis in males treated with norfloxacin

Directory of Open Access Journals (Sweden)

Chari KVR

1994-01-01

Full Text Available This subject was undertaken to confirm the efficacy of norfloxacin in acute gonorrhoea and to note the relapse if any during the follow up period of 3 months. 27 male patients suffering from acute gonorrhoea were treated with 800 mgs of norfloxacin as single oral dose. In all cases, gonococci disappeared from urethral smears by 8 hours, urethral discharge subsided by 72 hrs, urine on naked eye examination cleared in 4 days except in 1 case and burning micturition subsided by 7 days. Cure rate was 100% in the study. No relapse was found at the end of follow up of 3 months. No adverse reactions were observed to norfloxacin except headache in 2 cases. Norfloxacin was safe and effective in the treatment of acute gonorrhoea.

Urea utilization in growing lambs. 6

International Nuclear Information System (INIS)

Ulbrich, M.; Nikitin, S.; Geissler, C.; Hoffmann, M.

1988-01-01

Lambs aged 2 or 4 months and of an average live weight of 14.7 and 27.4 kg, resp., received rations consisting of 44% cereals, 46% dried sugar beet pulp, 6% wheat starch, 2% urea and 2% mineral-vitamin mixture. The crude protein content was 17.1 and 15.9%, resp., in the dry matter, that of natively crude protein 10.6 and 9.4%, resp. During a 6-day N balance period 8 and 16 g 15 N-urea resp. with a 15 N excess ( 15 N') of 9.26 and 9.40 atom-% were fed orally instead of commercial feeding urea. There were no significant differences between the two age groups with regard to the digestibility of the organic matter and the crude nutrients. The average N balance of 372 ± 85 mg/kg LW 0.75 /day were in the intermediate range of N retention capacity and accounted for 26 ± 5% of the consumed N. N retention in per cent. was slightly lower in younger lambs. Projections of urea utilization in a quasi stationary state resulted in an efficiency of the utilization of 33 ± 4%. The cutting up of the lambs at the end of the main period showed between 0.02 and 0.22 atom-% 15 N' in the total N, TCA precipitable N and amino acid N of the meat. At between 0.24 and 0.38 atom-% 15 N' they were highest in the heart and jaw muscles. The quota of 15 N' amounts found in the total N of the meat were 10.6 ± 3% of the 15 N intake and 20.1 ± 5.1% of the 15 N'amount remaining in the body. The bones contained 7.7 ± 1.7% and the fleece 7.9 ± 3.1% of the 15 N' intake. Total N and urea utilization was slightly lower in younger lambs than in older ones. (author)

21 CFR 184.1923 - Urea.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea. 184.1923 Section 184.1923 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1923 Urea. (a) Urea (CO(NH2)2, CAS Reg. No. 57-13-6) is the diamide of...

Thermoplastic poly(urethane urea)s from novel, bio-based amorphous polyester diols

NARCIS (Netherlands)

Tang, D.; Noordover, B.A.J.; Sablong, R.J.; Koning, C.E.

2012-01-01

In this study, two novel, bio-based, amorphous polyester diols, namely poly(1,2-dimethylethylene adipate) (PDMEA) and poly(1,2-dimethylethylene succinate) (PDMES) are used to prepare thermoplastic poly(urethane urea)s (TPUUs). Interestingly, the TPUUs based on PDMEA show similar thermal and

Cytoplasmic Histidine Kinase (HP0244)-Regulated Assembly of Urease with UreI, a Channel for Urea and Its Metabolites, CO2, NH3, and NH4+, Is Necessary for Acid Survival of Helicobacter pylori▿

OpenAIRE

Scott, David R.; Marcus, Elizabeth A.; Wen, Yi; Singh, Siddarth; Feng, Jing; Sachs, George

2009-01-01

Helicobacter pylori colonizes the normal human stomach by maintaining both periplasmic and cytoplasmic pH close to neutral in the presence of gastric acidity. Urease activity, urea flux through the pH-gated urea channel, UreI, and periplasmic α-carbonic anhydrase are essential for colonization. Exposure to pH 4.5 for up to 180 min activates total bacterial urease threefold. Within 30 min at pH 4.5, the urease structural subunits, UreA and UreB, and the Ni2+ insertion protein, UreE, are recrui...

Design and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatement

KAUST Repository

Lee, Junggil

2012-10-01

Urea-selective catalytic reduction (SCR) has been reported as the most promising technique for adherence to NOX emissions regulations. In the urea-SCR process, NH3 is generated by urea thermal decomposition and hydrolysis and is then used as a reductant of NOX in the SCR catalyst. Therefore, improving the NOX conversion efficiency of urea-SCR requires enhancement of thermal decomposition upstream of the SCR catalyst. In the present work, two types of mixing chambers were designed and fabricated to improve urea thermal decomposition, and experiments with and without a mixing chamber were carried out to analyze thermal-decomposition characteristics of urea in the exhaust pipe with respect to inlet velocity (4-12μm/s) and temperature (350°C-500°C). Urea thermal decomposition is greatly enhanced at higher gas temperatures. At an inlet velocity of 6μm/s in the A-type mixing chamber, NH3 concentrations generated along the exhaust pipe were about 171% and 157% greater than those without the mixing chamber for inlet temperatures of 400°C and 500°C, respectively. In the case of the B-type mixing chamber, NH3 concentrations generated at inlet temperatures of 400°C and 500°C were about 147% and 179% greater than those without the mixing chamber, respectively. Note that the implementation of mixing chambers significantly enhanced conversion of urea to NH3 because it increased the residence time of urea in the exhaust pipe and improved mixing between urea and exhaust gas. © 2012, Mary Ann Liebert, Inc.

Transfer of blood urea into the goat colon

International Nuclear Information System (INIS)

Engelhardt, W. von; Hinderer, S.

1976-01-01

Transfer of blood urea to the temporarily isolated and perfused colon of conscious goats was measured. Simultaneously, total urea turnover was estimated using 14 C-labelled urea. Three animals in the weight range 50-70 k were used, with appropriately placed cannulae. The entry of blood urea into the total gastrointestinal tract was estimated from the difference between total urea turnover renal urea excretion. When experimental conditions remained constant, such as the permeability of the gastrointestinal tract wall, blood urea diffusion into the colon depended on plasma urea concentration. Results of varying feeding conditions demonstrated that changes in permeability of the gastrointestinal tract will have a more pronounced influence on the amounts of blood urea entering the gastrointestinal tract than differences in plasma urea concentration

Effects of nitrogen supply on inter-organ fluxes of urea-N and renal urea-N kinetics in lactating Holstein cows

DEFF Research Database (Denmark)

Røjen, Betina Amdisen; Theil, Peter Kappel; Kristensen, Niels Bastian

2011-01-01

The effects of decreasing ruminal urea infusion in lactating dairy cows fed a basal diet deficient in rumen degradable protein on inter-organ urea-N fluxes, epithelial urea-N extraction, and renal urea-N kinetics were investigated. Eight Danish Holstein cows fitted with a ruminal cannula...... and permanent indwelling catheters in the major splanchnic blood vessels and the gastrosplenic vein were used. The cows were randomly allocated to a triplicate incomplete 3 × 3 Latin square design with 14-d periods. Treatments were continuous ventral ruminal infusion of water, 4.1 g of feed urea/kg of dry...... matter intake, and 8.5 g of feed urea/kg of dry matter intake. Dry matter intake and milk yield decreased linearly with decreasing urea infusion. Arterial blood urea-N and ruminal ammonia concentrations decreased linearly with decreasing urea infusion. In absolute amounts, the urea-N recycling did...

Nitrogen uptake and balance of the fertilizers urea, urea with urease inhibitor, and ammonium nitrate applied to spring wheat at stem elongation growth stage

International Nuclear Information System (INIS)

Matzel, W.; Lippold, H.; Heber, R.

1979-01-01

The use of urea containing 1% of diamido phosphoric acid phenyl ester, which is a urease inhibitor, for the top dressing of spring wheat on light soil allows the loss of nitrogen due to volatilization of ammonia from urea to be prevented. The urease inhibitor has no effect whatsoever upon the uptake of urea nitrogen by spring wheat. Even in those cases where the volatilization of ammonia is prevented, plants will take up 5 to 6% less nitrogen from urea than from ammonium nitrate. This is due primarily to the higher degree of immobilization of urea nitrogen in the soil. The volatilization of ammonia from urea applied to the surface of the soil was in the region of 25% when the soil surface was moist and 10% when the soil surface was dry, the percentages given above being related to the amount of fertilizer nitrogen applied to the soil. The plant uptake of fertilizer nitrogen applied as a second dose at stem elongation will be complete after two to three weeks or after six weeks under favourable or unfavourable conditions, respectively. Proceeding immediately after application of the fertilizer nitrogen are the processes resulting in both loss of nitrogen and its immobilization. The proportion of absorbed fertilizer nitrogen recovered in the grain will be the greater the later the nitrogen is incorporated into the plant. The use in pot experiments of labelled nitrogen fertilizers enables statistically significant differences in effects to be determined even in those cases in which the differences are only relatively small in degree. (author)

Development of an Optical Urea Biosensor Using Polypyrrole-polyvinyl Sulphonate Film

Directory of Open Access Journals (Sweden)

H. J. KHARAT

2009-02-01

Full Text Available Development of an intensity modulated fiber optic PPy-PVS biosensor for the detection of urea has been presented. The sensor design is based on the modified cladding technique. Polypyrrole (PPy film doped with polyvinyl sulfonate (PVS was synthesized (by in-situ chemical polymerization at room temperature with optimized process parameters. The PPy-PVS film provides good porous matrix for the immobilization of enzyme-urease on the sensing probe by cross linking via glutaraldehyde. The characterization of the urea biosensor has been carried out with an indigenously developed sensing chamber and optical fiber test bench. This biosensor showed almost stable and linear response to urea in the range 1-100 mM up to 24 days. It shows very good selectivity and repeatability.

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

Science.gov (United States)

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

2013-01-01

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

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

Directory of Open Access Journals (Sweden)

Chris M. Wood

2013-02-01

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

Determination of urea 13C in urea 13C mixed powder by HPLC

International Nuclear Information System (INIS)

Zhong Jianguo; Song Tianqi

2006-01-01

A HPLC method is developed for determination of Urea 13 C in Urea 13 C Mixed Powder. A Alltech Econosphere NH2 column (250 mm x 4.6 mm, 5 μm)is used as stationary phrase, a mixture of V(acetonitrile): V(methanol): V(water) = 900 : 100: 10 is used as mobile phase and the flow rate is l mL·min -1 , UV detection wavelength is performed at 200 nm. The calibration curve shows good linearity in the range of 0.2-1.0 g·L -1 of Urea 13 C, y=2.548 x 10 6 x + 4.005 x 10 4 , r=0.9999, and the averaged recovery is 100.6%. The method is simple and accurate, and can be used for the quality control of Urea 13C Mixed Powder. (authors)

Up-regulation of CLDN1 in gastric cancer is correlated with reduced survival

International Nuclear Information System (INIS)

Eftang, Lars L; Esbensen, Ying; Tannæs, Tone M; Blom, Gustav P; Bukholm, Ida RK; Bukholm, Geir

2013-01-01

The genetic changes in gastric adenocarcinoma are extremely complex and reliable tumor markers have not yet been identified. There are also remarkable geographical differences in the distribution of this disease. Our aim was to identify the most differentially regulated genes in 20 gastric adenocarcinomas from a Norwegian selection, compared to matched normal mucosa, and we have related our findings to prognosis, survival and chronic Helicobacter pylori infection. Biopsies from gastric adenocarcinomas and adjacent normal gastric mucosa were obtained from 20 patients immediately following surgical resection of the tumor. Whole genome, cDNA microarray analysis was performed on the RNA isolated from the sample pairs to compare the gene expression profiles between the tumor against matched mucosa. The samples were microscopically examined to classify gastritis. The presence of H. pylori was examined using microscopy and immunohistochemistry. 130 genes showed differential regulation above a predefined cut-off level. Interleukin-8 (IL-8) and Claudin-1 (CLDN1) were the most consistently up-regulated genes in the tumors. Very high CLDN1 expression in the tumor was identified as an independent and significant predictor gene of reduced post-operative survival. There were distinctly different expression profiles between the tumor group and the control mucosa group, and the histological subsets of mixed type, diffuse type and intestinal type cancer demonstrated further sub-clustering. Up-regulated genes were mapped to cell-adhesion, collagen-related processes and angiogenesis, whereas normal intestinal functions such as digestion and excretion were associated with down-regulated genes. We relate the current findings to our previous study on the gene response of gastric epithelial cells to H. pylori infection. CLDN1 was highly up-regulated in gastric cancer, and CLDN1 expression was independently associated with a poor post-operative prognosis, and may have important prognostic

A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme

Directory of Open Access Journals (Sweden)

Musa Ahmad

2007-10-01

Full Text Available An optical urea biosensor was fabricated by stacking several layers of sol-gelfilms. The stacking of the sol-gel films allowed the immobilization of a Nile Bluechromoionophore (ETH 5294 and urease enzyme separately without the need of anychemical attachment procedure. The absorbance response of the biosensor was monitoredat 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel filmformat enabled higher enzyme loading in the biosensor to be achieved. The urea opticalbiosensor constructed from three layers of sol-gel films that contained urease demonstrateda much wider linear response range of up to 100 mM urea when compared with biosensorsthat constructed from 1-2 layers of films. Analysis of urea in urine samples with thisoptical urea biosensor yielded results similar to that determined by a spectrophotometricmethod using the reagent p-dimethylaminobenzaldehyde (R2 = 0.982, n = 6. The averagerecovery of urea from urine samples using this urea biosensor is approximately 103%.

A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme.

Science.gov (United States)

Alqasaimeh, Muawia Salameh; Heng, Lee Yook; Ahmad, Musa

2007-10-11

An optical urea biosensor was fabricated by stacking several layers of sol-gelfilms. The stacking of the sol-gel films allowed the immobilization of a Nile Bluechromoionophore (ETH 5294) and urease enzyme separately without the need of anychemical attachment procedure. The absorbance response of the biosensor was monitoredat 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel filmformat enabled higher enzyme loading in the biosensor to be achieved. The urea opticalbiosensor constructed from three layers of sol-gel films that contained urease demonstrateda much wider linear response range of up to 100 mM urea when compared with biosensorsthat constructed from 1-2 layers of films. Analysis of urea in urine samples with thisoptical urea biosensor yielded results similar to that determined by a spectrophotometricmethod using the reagent p-dimethylaminobenzaldehyde (R² = 0.982, n = 6). The averagerecovery of urea from urine samples using this urea biosensor is approximately 103%.

Counteraction of urea-induced protein denaturation by trimethylamine N-oxide: a chemical chaperone at atomic resolution.

Science.gov (United States)

Bennion, Brian J; Daggett, Valerie

2004-04-27

Proteins are very sensitive to their solvent environments. Urea is a common chemical denaturant of proteins, yet some animals contain high concentrations of urea. These animals have evolved an interesting mechanism to counteract the effects of urea by using trimethylamine N-oxide (TMAO). The molecular basis for the ability of TMAO to act as a chemical chaperone remains unknown. Here, we describe molecular dynamics simulations of a small globular protein, chymotrypsin inhibitor 2, in 8 M urea and 4 M TMAO/8 M urea solutions, in addition to other control simulations, to investigate this effect at the atomic level. In 8 M urea, the protein unfolds, and urea acts in both a direct and indirect manner to achieve this effect. In contrast, introduction of 4 M TMAO counteracts the effect of urea and the protein remains well structured. TMAO makes few direct interactions with the protein. Instead, it prevents unfolding of the protein by structuring the solvent. In particular, TMAO orders the solvent and discourages it from competing with intraprotein H bonds and breaking up the hydrophobic core of the protein.

Relationship between cognitive emotion regulation, social support, resilience and acute stress responses in Chinese soldiers: Exploring multiple mediation model.

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Cai, Wen-Peng; Pan, Yu; Zhang, Shui-Miao; Wei, Cun; Dong, Wei; Deng, Guang-Hui

2017-10-01

The current study aimed to explore the association of cognitive emotion regulation, social support, resilience and acute stress responses in Chinese soldiers and to understand the multiple mediation effects of social support and resilience on the relationship between cognitive emotion regulation and acute stress responses. A total of 1477 male soldiers completed mental scales, including the cognitive emotion regulation questionnaire-Chinese version, the perceived social support scale, the Chinese version of the Connor-Davidson resilience scale, and the military acute stress scale. As hypothesized, physiological responses, psychological responses, and acute stress were associated with negative-focused cognitive emotion regulation, and negatively associated with positive-focused cognitive emotion regulation, social supports and resilience. Besides, positive-focused cognitive emotion regulation, social support, and resilience were significantly associated with one another, and negative-focused cognitive emotion regulation was negatively associated with social support. Regression analysis and bootstrap analysis showed that social support and resilience had partly mediating effects on negative strategies and acute stress, and fully mediating effects on positive strategies and acute stress. These results thus indicate that military acute stress is significantly associated with cognitive emotion regulation, social support, and resilience, and that social support and resilience have multiple mediation effects on the relationship between cognitive emotion regulation and acute stress responses. Copyright © 2017 Elsevier B.V. All rights reserved.

Acute metabolic decompensation due to influenza in a mouse model of ornithine transcarbamylase deficiency

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Peter J. McGuire

2014-02-01

Full Text Available The urea cycle functions to incorporate ammonia, generated by normal metabolism, into urea. Urea cycle disorders (UCDs are caused by loss of function in any of the enzymes responsible for ureagenesis, and are characterized by life-threatening episodes of acute metabolic decompensation with hyperammonemia (HA. A prospective analysis of interim HA events in a cohort of individuals with ornithine transcarbamylase (OTC deficiency, the most common UCD, revealed that intercurrent infection was the most common precipitant of acute HA and was associated with markers of increased morbidity when compared with other precipitants. To further understand these clinical observations, we developed a model system of metabolic decompensation with HA triggered by viral infection (PR8 influenza using spf-ash mice, a model of OTC deficiency. Both wild-type (WT and spf-ash mice displayed similar cytokine profiles and lung viral titers in response to PR8 influenza infection. During infection, spf-ash mice displayed an increase in liver transaminases, suggesting a hepatic sensitivity to the inflammatory response and an altered hepatic immune response. Despite having no visible pathological changes by histology, WT and spf-ash mice had reduced CPS1 and OTC enzyme activities, and, unlike WT, spf-ash mice failed to increase ureagenesis. Depression of urea cycle function was seen in liver amino acid analysis, with reductions seen in aspartate, ornithine and arginine during infection. In conclusion, we developed a model system of acute metabolic decompensation due to infection in a mouse model of a UCD. In addition, we have identified metabolic perturbations during infection in the spf-ash mice, including a reduction of urea cycle intermediates. This model of acute metabolic decompensation with HA due to infection in UCD serves as a platform for exploring biochemical perturbations and the efficacy of treatments, and could be adapted to explore acute decompensation in other

Application of lime and urea and its effect on development of Phythophthora palmivora.

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Sakti Widyanta Pratama

2015-03-01

Full Text Available Black pod rot disease (BPRD which is caused by Phytophthora palmivora is one of the main diseases of cocoa cultivations particularly in plantations with wet climate. Black pod rot can develop rapidly under high humidity environments, particularly during rainy seasons. This disease can cause loss of harvest of up to 46.63% in East Java. The various control efforts attempted so far have not resulted in significant improvements. Urea, in addition to functioning as fertilizer, can also produce the ammonia gas which is believed to be able to suppress black pod rot. This research aims to determine the effectiveness of black pod rot control using the combination of lime and urea. This research was conducted from June to September 2013. The materials used in test included sterile soil, black pod rot infected cocoa, urea, and agricultural lime. Observation results showed that ammonia could form from urea. Lime can increase the speed of the formation. The ammonia gas forming from 0.06% urea and 0.3% lime can control the P. palmivora fungus inside the soil. Key words: Pod rot, P. palmivora, urea, lime, ammonia

The influence of acute stress on the regulation of conditioned fear

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Candace M. Raio

2015-01-01

Full Text Available Fear learning and regulation is a prominent model for describing the pathogenesis of anxiety disorders and stress-related psychopathology. Fear expression can be modulated using a number of regulatory strategies, including extinction, cognitive emotion regulation, avoidance strategies and reconsolidation. In this review, we examine research investigating the effects of acute stress and stress hormones on these regulatory techniques. We focus on what is known about the impact of stress on the ability to flexibly regulate fear responses that are acquired through Pavlovian fear conditioning. Our primary aim is to explore the impact of stress on fear regulation in humans. Given this, we focus on techniques where stress has been linked to alterations of fear regulation in humans (extinction and emotion regulation, and briefly discuss other techniques (avoidance and reconsolidation where the impact of stress or stress hormones have been mainly explored in animal models. These investigations reveal that acute stress may impair the persistent inhibition of fear, presumably by altering prefrontal cortex function. Characterizing the effects of stress on fear regulation is critical for understanding the boundaries within which existing regulation strategies are viable in everyday life and can better inform treatment options for those who suffer from anxiety and stress-related psychopathology.

Are de novo acute heart failure and acutely worsened chronic heart failure two subgroups of the same syndrome?

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Banović Marko

2010-01-01

Full Text Available Introduction. Acute heart failure (AHF is one of the most common diseases in emergency medicine, associated with poor prognosis and high in-hospital and long-term mortality. Objective. To investigate clinical presentation of patients with de novo AHF and acute worsening of chronic heart failure (CHF and to identify differences in blood levels of biomarkers and echocardiography findings. Methods. This prospective study comprised 64 consecutive patients being grouped according to the onset of the disease into patients with the de novo AHF (45.3%, and patients with acute worsening of CHF (54.7%. Results. Acute congestion (60% was the most common manifestation of de novo AHF, whereas pulmonary oedema (43.1% was the most common manifestation of acutely decompensated CHF. Patients with acutely decompensated CHF had significantly higher blood values of creatinine (147.10 vs 113.16 μmol/l; p<0.05, urea (12.63 vs 7.82 mmol/l; p<0.05, BNP (1440.11 vs 712.24 pg/ml; p<001 and NTproBNP (9097.00 vs 2827.70 pg/ml; p<0.01 on admission, and lower values of M-mode left ventricular ejection fraction (LVEF during hospitalization (49.44% vs 42.94%; p<0.05. The follow-up after one year revealed still significantly higher BNP (365.49 vs 164.02 pg/ ml; p<0.05 and lower average values of both LVEF in patients with acutely worsened CHF (46.62% vs 54.41% and 39.52% vs 47.88%; p<0.05. Conclusion. Considering differences in clinical severity on admission, echocardiography and natriuretic peptide values during hospitalization and after one year follow-up, de novo AHF and acutely worsened CHF are two different subgroups of the same syndrome.

Moist skin care can diminish acute radiation-induced skin toxicity

International Nuclear Information System (INIS)

Momm, F.; Weissenberger, C.; Bertelt, S.; Henke, M.

2003-01-01

Background: Radiation treatment may induce acute skin reactions. There are several methods of managing them. Validity of these methods, however, is not sufficiently studied. We therefore investigated, whether moist skin care with 3% urea lotion will reduce acute radiation skin toxicity. Patients and Methods: 88 patients with carcinomas of the head and neck undergoing radiotherapy with curative intent (mean total dose 60 Gy, range: 50-74 Gy) were evaluated weekly for acute skin reactions according to the RTOG-CTC score. In 63 patients, moist skin care with 3% urea lotion was performed. The control group consisted of 25 patients receiving conventional dry skin care. The incidence of grade I, II, and III reactions and the radiation dose at occurrence of a particular reaction were determined and statistically analyzed using the log-rank test. The dose-time relations of individual skin reactions are described. Results: At some point of time during radiotherapy, all patients suffered from acute skin reactions grade I, > 90% from grade II reactions. 50% of patients receiving moist skin care experienced grade I reactions at 26 Gy as compared to 22 Gy in control patients (p = 0.03). Grade II reactions occurred at 51 Gy versus 34 Gy (p = 0.006). Further, 22% of the patients treated with moist skin care suffered from acute skin toxicity grade III as compared to 56% of the controls (p = 0.0007). Conclusion: Moist skin care with 3% urea lotion delays the occurrence and reduces the grade of acute skin reactions in percutaneously irradiated patients with head and neck tumors. (orig.)

Determination of urea content in urea cream by centrifugal partition chromatography

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Ying-Qun Wang

2016-04-01

Full Text Available The objective of this study is to establish a centrifugal partition chromatography (CPC method for determination of the urea ingredient in urea cream. The mechanism of this method is that urea is determined by UV detector at 430 nm after being extracted from the cream and derivatized on line via Ehrlich reaction in rotor of CPC, where the reaction products dissolve in the mobile phase and the cream matrix retains in the stationary phase. The mixed solvent consisting of n-hexane, methanol, hydrochloric acid and p-dimethylaminobenzaldehyde with a ratio of 1000 mL:1000 mL:18 mL:2.0 g is used for solvent system of CPC. The CPC method proposed offers good precision and convenience without complex sample pretreatment processes.

Ammonia volatilization from coated urea forms

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Carlos Antonio Costa do Nascimento

2013-08-01

Full Text Available Nitrogen fertilization is a major component of the cost of agricultural production, due to the high cost and low efficiency of fertilizers. In the case of urea, the low efficiency is mainly due to losses by volatilization, which are more pronounced in cultivation systems in which plant residues are left on the soil. The objective of this work was to compare the influence of urea coated with sulfur or boric acid and copper sulfate with conventional N fertilizers on N volatilization losses in sugar cane harvested after stubble burning. The sources urea, sulfur-coated urea, urea coated with boric acid and copper sulfate, as well as nitrate and ammonium sulfate, were tested at amounts containing N rates of 120 kg ha-1 N. The integration of new technologies in urea fertilization can reduce N losses by volatilization. These losses were most reduced when using nitrate and ammonium sulfate. The application of a readily acidified substance (boric acid to urea was more efficient in reducing volatilization losses and nutrient removal by sugar cane than that of a substance with gradual acidification (elemental sulfur.

Long-Term Serological Follow-Up of Acute Q-Fever Patients after a Large Epidemic.

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Cornelia C H Wielders

Full Text Available Serological follow-up of acute Q-fever patients is important for detection of chronic infection but there is no consensus on its frequency and duration. The 2007-2009 Q-fever epidemic in the Netherlands allowed for long-term follow-up of a large cohort of acute Q-fever patients. The aim of this study was to validate the current follow-up strategy targeted to identify patients with chronic Q-fever.A cohort of adult acute Q-fever patients, diagnosed between 2007 and 2009, for whom a twelve-month follow-up sample was available, was invited to complete a questionnaire and provide a blood sample, four years after the acute episode. Antibody profiles, determined by immunofluorescence assay in serum, were investigated with a special focus on high titres of IgG antibodies against phase I of Coxiella burnetii, as these are considered indicative for possible chronic Q-fever.Of the invited 1,907 patients fulfilling inclusion criteria, 1,289 (67.6% were included in the analysis. At any time during the four-year follow-up period, 58 (4.5% patients were classified as possible, probable, or proven chronic Q-fever according to the Dutch Q-fever Consensus Group criteria (which uses IgG phase I ≥1:1,024 to as serologic criterion for chronic Q-fever. Fifty-two (89.7% of these were identified within the first year after the acute episode. Of the six patients that were detected for the first time at four-year follow-up, five had an IgG phase I titre of 1:512 at twelve months.A twelve-month follow-up check after acute Q-fever is recommended as it adequately detects chronic Q-fever in patients without known risk factors. Additional serological and clinical follow-up is recommended for patients with IgG phase I ≥1:512, as they showed the highest risk to progress to chronic Q-fever.

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

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

2013-09-01

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

Detection of urea-induced internal denaturation of dsDNA using solid-state nanopores.

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Singer, Alon; Kuhn, Heiko; Frank-Kamenetskii, Maxim; Meller, Amit

2010-11-17

The ability to detect and measure dsDNA thermal fluctuations is of immense importance in understanding the underlying mechanisms responsible for transcription and replication regulation. We describe here the ability of solid-state nanopores to detect sub-nanometer changes in DNA structure as a result of chemically enhanced thermal fluctuations. In this study, we investigate the subtle changes in the mean effective diameter of a dsDNA molecule with 3-5 nm solid-state nanopores as a function of urea concentration and the DNA's AT content. Our studies reveal an increase in the mean effective diameter of a DNA molecule of approximately 0.6 nm at 8.7 M urea. In agreement with the mechanism of DNA local denaturation, we observe a sigmoid dependence of these effects on urea concentration. We find that the translocation times in urea are markedly slower than would be expected if the dynamics were governed primarily by viscous effects. Furthermore, we find that the sensitivity of the nanopore is sufficient to statistically differentiate between DNA molecules of nearly identical lengths differing only in sequence and AT content when placed in 3.5 M urea. Our results demonstrate that nanopores can detect subtle structural changes and are thus a valuable tool for detecting differences in biomolecules' environment.

Detection of urea-induced internal denaturation of dsDNA using solid-state nanopores

International Nuclear Information System (INIS)

Singer, Alon; Kuhn, Heiko; Frank-Kamenetskii, Maxim; Meller, Amit

2010-01-01

The ability to detect and measure dsDNA thermal fluctuations is of immense importance in understanding the underlying mechanisms responsible for transcription and replication regulation. We describe here the ability of solid-state nanopores to detect sub-nanometer changes in DNA structure as a result of chemically enhanced thermal fluctuations. In this study, we investigate the subtle changes in the mean effective diameter of a dsDNA molecule with 3-5 nm solid-state nanopores as a function of urea concentration and the DNA's AT content. Our studies reveal an increase in the mean effective diameter of a DNA molecule of approximately 0.6 nm at 8.7 M urea. In agreement with the mechanism of DNA local denaturation, we observe a sigmoid dependence of these effects on urea concentration. We find that the translocation times in urea are markedly slower than would be expected if the dynamics were governed primarily by viscous effects. Furthermore, we find that the sensitivity of the nanopore is sufficient to statistically differentiate between DNA molecules of nearly identical lengths differing only in sequence and AT content when placed in 3.5 M urea. Our results demonstrate that nanopores can detect subtle structural changes and are thus a valuable tool for detecting differences in biomolecules' environment.

Determination of urea kinetics by isotope dilution with [C-13]urea and gas chromatography isotope ratio mass spectrometry (GC-IRMS) analysis

NARCIS (Netherlands)

Kloppenburg, Wybe; Wolthers, BG; Stellaard, F; Elzinga, H; Tepper, T; deJong, PE; Huisman, RM

1. Stable urea isotopes can be used to study urea kinetics in humans, The use of stable urea isotopes far studying urea kinetic parameters in humans on a large scale is hampered by the high costs of the labelled material, We devised a urea dilution for measurement of the distribution volume,

40 CFR 721.9892 - Alkylated urea.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylated urea. 721.9892 Section 721... Alkylated urea. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an alkylated urea (PMN P-93-1649) is subject to reporting under this...

40 CFR 721.9928 - Urea, tetraethyl-.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Urea, tetraethyl-. 721.9928 Section... Substances § 721.9928 Urea, tetraethyl-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as urea, tetraethyl- (PMN P-94-1017; CAS No. 1187-03-7) is...

Prognostic value of the urea:creatinine ratio in decompensated heart failure and its relationship with acute kidney damage.

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Josa-Laorden, C; Sola, A; Giménez-López, I; Rubio-Gracia, J; Garcés-Horna, V; Pérez-Calvo, J I

Worsening renal function is associated with an adverse prognosis for patients with acute heart failure (AHF). Urea-creatinine ratio (U:C ratio) might be useful for measuring renal function and could help stratify patients with AHF. An observational and prospective study was conducted to analyse the prognostic value of the U:C ratio, measured during the first 24-28 hours of admission, for patients hospitalised for decompensated Heart failure, and its relationship with estimated glomerular filtration rate (eGFR) and acute kidney injury (AKI). The study included 204 patients, with a mean age of 79.3 years, and a median eGFR of 55 mL/min/1.73m 2 . In the multivariate analysis, an U:C ratio above the median (50) was related to the development of AKI (36.5% vs. 21.9%) and to increased mortality, both overall (OR 2.75) and by HF (OR 3.50) in long term. In combination with eGFR, the U:C ratio showed prognostic value in patients with normal eGFR (mortality of 4.4% for an U:C ratio ≤ 50 vs. 22% for U:C ratio > 50; p=0.01), as well as a better predictive capacity for AKI than each of them separately (AUC, 0.718; 95% CI 0.643-0.793; p>.000). An U:C ratio > 50 is a predictor of increased long-term mortality for patients hospitalised for decompensated HF and with normal eGFR. Given the simplicity of this biomarker, its use in clinical practice should be more systematic. Copyright © 2018 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.

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

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

2016-03-01

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

Impact of newly diagnosed abnormal glucose regulation on long-term prognosis in low risk patients with ST-elevation myocardial infarction: A follow-up study

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Abdelnoor Michael

2011-07-01

Full Text Available Abstract Background Patients with acute myocardial infarction and newly detected abnormal glucose regulation have been shown to have a less favourable prognosis compared to patients with normal glucose regulation. The importance and timing of oral glucose tolerance testing (OGTT in patients with acute myocardial infarction without known diabetes is uncertain. The aim of the present study was to evaluate the impact of abnormal glucose regulation classified by an OGTT in-hospital and at three-month follow-up on clinical outcome in patients with acute ST elevation myocardial infarction (STEMI without known diabetes. Methods Patients (n = 224, age 58 years with a primary percutanous coronary intervention (PCI treated STEMI were followed for clinical events (all-cause mortality, non-fatal myocardial re-infarction, recurrent ischemia causing hospital admission, and stroke. The patients were classified by a standardised 75 g OGTT at two time points, first, at a median time of 16.5 hours after hospital admission, then at three-month follow-up. Based on the OGTT results, the patients were categorised according to the WHO criteria and the term abnormal glucose regulation was defined as the sum of impaired fasting glucose, impaired glucose tolerance and type 2-diabetes. Results The number of patients diagnosed with abnormal glucose regulation in-hospital and at three-month was 105 (47% and 50 (25%, respectively. During the follow up time of (median 33 (27, 39 months, 58 (25.9% patients experienced a new clinical event. There were six deaths, 15 non-fatal re-infarction, 33 recurrent ischemia, and four strokes. Kaplan-Meier analysis of survival free of composite end-points showed similar results in patients with abnormal and normal glucose regulation, both when classified in-hospital (p = 0.4 and re-classified three months later (p = 0.3. Conclusions Patients with a primary PCI treated STEMI, without previously known diabetes, appear to have an excellent

A Randomized Control Intervention Investigating the Effects of Acute Exercise on Emotional Regulation.

Science.gov (United States)

Edwards, Meghan K; Rhodes, Ryan E; Loprinzi, Paul D

2017-09-01

Exercise may help to cope with hectic or demanding events after a stressful situation occurs. Limited research has evaluated whether exercise, prior to a stressor, helps to facilitate subsequent emotional regulation. This pilot study addresses this novel paradigm. We employed a randomized controlled trial evaluating the effects of acute exercise on emotional regulation. Participants were randomly assigned to stretch (control group, N = 10), walk (N = 9), or jog (N = 8) for 15-minutes, after which they were exposed to a film clip intended to elicit a negative emotional response. Participants' emotions were monitored before and during exercise, as well as after the film clip. Emotional responses were evaluated using the Exercise Induced Feeling Inventory and Affective Circumplex Scale. A group x time splitplot interaction effect was significant for anger (p = .046) and anxiousness (p = .038). Follow-up analyses showed that only the stretching group (p = .048) had a significantly increased anger score from baseline to post-film clip, suggesting a protective emotional effect from walking and jogging. Exercise was effective in regulating anger and anxiousness after a stressful event. These findings provide evidence for potential preventive effects of exercise in facilitating emotional regulation.

Waste-to-Chemicals for a Circular Economy: The Case of Urea Production (Waste-to-Urea).

Science.gov (United States)

Antonetti, Elena; Iaquaniello, Gaetano; Salladini, Annarita; Spadaccini, Luca; Perathoner, Siglinda; Centi, Gabriele

2017-03-09

The economics and environmental impact of a new technology for the production of urea from municipal solid waste, particularly the residue-derived fuel (RdF) fraction, is analyzed. Estimates indicate a cost of production of approximately €135 per ton of urea (internal rate of return more than 10 %) and savings of approximately 0.113 tons of CH 4 and approximately 0.78 tons of CO 2 per ton of urea produced. Thus, the results show that this waste-to-urea (WtU) technology is both economically valuable and environmentally advantageous (in terms of saving resources and limiting carbon footprint) for the production of chemicals from municipal solid waste in comparison with both the production of urea with conventional technology (starting from natural gas) and the use of RdF to produce electrical energy (waste-to-energy). A further benefit is the lower environmental impact of the solid residue produced from RdF conversion. The further benefit of this technology is the possibility to realize distributed fertilizer production. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel dimer based descriptors with solvational computation for QSAR study of oxadiazoylbenzoyl-ureas as novel insect-growth regulators.

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Fan, Feng; Cheng, Jiagao; Li, Zhong; Xu, Xiaoyong; Qian, Xuhong

2010-02-01

Molecular aggregation state of bioactive compounds plays a key role in its bio-interactive procedure. In this article, based on the structure information of dimers, the simplest model of molecular aggregation state, and combined with solvational computation, total four descriptors (DeltaV, MR2, DeltaE(1), and DeltaE(2)) were calculated for QSAR study of a novel insect-growth regulator, N-(5-phenyl-1,3,4-oxadiazol-2-yl)-N'-benzoyl urea. Two QSAR models were constructed with r(2) = 0.671, q(2) = 0.516 and r(2) = 0.816, q(2) = 0.695, respectively. It implicates that the bioactivity may strongly depend on the characters of molecular aggregation state, especially on the dimeric transport ability from oil phase to water phase. Copyright 2009 Wiley Periodicals, Inc.

The urea cycle disorders.

Science.gov (United States)

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

2014-07-01

The urea cycle is the primary nitrogen-disposal pathway in humans. It requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate, and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. Accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurologic sequelae. The disorders may present at any age from the neonatal period to adulthood, with the more severely affected patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. Here the authors address neurologic presentations of ornithine transcarbamylase deficiency in detail, the most common of the urea cycle disorders, neuropathology, neurophysiology, and our studies in neuroimaging. Special attention to late-onset presentations is given. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Enhanced Productivity of a Lutein-Enriched Novel Acidophile Microalga Grown on Urea

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Carlos Vilchez

2010-12-01

Full Text Available Coccomyxa acidophila is an extremophile eukaryotic microalga isolated from the Tinto River mining area in Huelva, Spain. Coccomyxa acidophila accumulates relevant amounts of b-carotene and lutein, well-known carotenoids with many biotechnological applications, especially in food and health-related industries. The acidic culture medium (pH < 2.5 that prevents outdoor cultivation from non-desired microorganism growth is one of the main advantages of acidophile microalgae production. Conversely, acidophile microalgae growth rates are usually very low compared to common microalgae growth rates. In this work, we show that mixotrophic cultivation on urea efficiently enhances growth and productivity of an acidophile microalga up to typical values for common microalgae, therefore approaching acidophile algal production towards suitable conditions for feasible outdoor production. Algal productivity and potential for carotenoid accumulation were analyzed as a function of the nitrogen source supplied. Several nitrogen conditions were assayed: nitrogen starvation, nitrate and/or nitrite, ammonia and urea. Among them, urea clearly led to the best cell growth (~4 ´ 108 cells/mL at the end of log phase. Ammonium led to the maximum chlorophyll and carotenoid content per volume unit (220 mg·mL-1 and 35 mg·mL-1, respectively. Interestingly, no significant differences in growth rates were found in cultures grown on urea as C and N source, with respect to those cultures grown on nitrate and CO2 as nitrogen and carbon sources (control cultures. Lutein accumulated up to 3.55 mg·g-1 in the mixotrophic cultures grown on urea. In addition, algal growth in a shaded culture revealed the first evidence for an active xanthophylls cycle operative in acidophile microalgae.

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

NARCIS (Netherlands)

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

2013-01-01

Dietary protein and salt affect the concentration of milk urea nitrogen (MUN; mg of N/dL) and the relationship between MUN and excretion of urea nitrogen in urine (UUN; g of N/d) of dairy cattle. The aim of the present study was to examine the effects of dietary protein and sodium chloride (NaCl)

Quantitative aspect of the endogenous urea cycle in goats

International Nuclear Information System (INIS)

Ide, Yu

1975-01-01

The turnover of plasma urea was studied in goats fed rations with different protein contents by using 14 C- and 15 N-urea as tracers. The biological half-life time of urea determined with 15 N-urea was always longer than that determined with 14 C-urea, reflecting the difference in the metabolic pathway between the urea hydrolysates, ammonia and carbon dioxide. It was roughly estimated from the turnover studies that more than a half the quantity of urea synthesized might be transferred to the alimentary canal, including the rumen, where it underwent dissociation, with a decrease in the protein content of the ration, the percentage of transfer and dissociation increased. The 14 C-urea discharged into the urine was less than 57% of the administered dose. It decreased to 3.9% in goats fed rations with a low protein content. The rate of urea turnover determined with 15 N-urea was nearly consistent with the rate of urea discharge into the urine in goats fed higher protein rations. In goats fed lower protein rations, on the other hand, the rate of urea discharge decreased and its consistency with the rate of turnover determined with 15 N-urea was upset. This was caused by assimilation of urea-nitrogen in rumen microorganisms, as was convinced by studying the incorporation of urea- 15 N into the fraction of rumen microorganisms. It was assumed that in goats fed lower protein rations the bulk of urea synthesized might have entered the endogenous recycling system within the body and assimilated by rumen microorganisms. (auth.)

Patients with computed tomography-proven acute diverticulitis require follow-up to exclude colorectal cancer

Directory of Open Access Journals (Sweden)

Shafquat Zaman

2017-04-01

Full Text Available Background/Aims: Traditionally, patients with acute diverticulitis undergo follow-up endoscopy to exclude colorectal cancer (CRC. However, its usefulness has been debated in this era of high-resolution computed tomography (CT diagnosis. We assessed the frequency and outcome of endoscopic follow-up for patients with CT-proven acute diverticulitis, according to the confidence in the CT diagnosis.Methods: Records of patients with CT-proven acute diverticulitis between October 2007 and March 2014 at Sandwell & West Birmingham Hospitals NHS Trust were retrieved. The National Cancer Registry confirmed the cases of CRC. Endoscopy quality indicators were compared between these patients and other patients undergoing the same endoscopic examination over the same period.Results: We identified 235 patients with CT-proven acute diverticulitis, of which, 187 were managed conservatively. The CT report was confident of the diagnosis of acute diverticulitis in 75% cases. Five of the 235 patients were subsequently diagnosed with CRC (2.1%. Three cases of CRC were detected in the 187 patients managed conservatively (1.6%. Forty-eight percent of the conservatively managed patients underwent follow-up endoscopy; one case of CRC was identified. Endoscopies were often incomplete and caused more discomfort for patients with diverticulitis compared with controls.Conclusions: CRC was diagnosed in patients with CT-proven diverticulitis at a higher rate than in screened asymptomatic populations, necessitating follow-up. CT reports contained statements regarding diagnostic uncertainty in 25% cases, associated with an increased risk of CRC. Follow-up endoscopy in patients with CT-proven diverticulitis is associated with increased discomfort and high rates of incompletion. The use of other follow-up modalities should be considered.

Milk Urea Dynamics during its Transformation into Yogurt

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Cornelia Vintila

2011-10-01

Full Text Available The purpose of our work was to evaluate in what measure milk urea concentration stays in processed yogurt and in what measure urea dose influences its quality. We added known amounts of urea into milk destined to yogurt processing in order to obtain probes with concentrations from 0,5 to 28 mg/ 100 ml milk. Obtained results lead us to the conclusion that milk urea decreases dramatically until the finishing of the process of milk coagulation and its transformation into yogurt. All probes which contained higher amounts of urea than 6 mg/ 100 ml milk, urea totally disappeared from yogurt before 48 hours of keeping. Milk coagulation time and its transformation to yogurt is reduced proportional with urea concentration in milk.

Potentiometric urea biosensor based on an immobilised fullerene-urease bio-conjugate.

Science.gov (United States)

Saeedfar, Kasra; Heng, Lee Yook; Ling, Tan Ling; Rezayi, Majid

2013-12-06

A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate) (PnBA) membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10-3 M to 8.28 × 10-5 M. The biosensor's sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor's response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

Treating agent for urea containing radioactive materials

International Nuclear Information System (INIS)

Ogawa, Hiroshi; Maki, Kentaro.

1973-01-01

Object: To add a coagulant into urea containing radioactive material to precipitate and remove the radioactive material in the urea. Structure: Iodosalt is added into urea and next, a mixed reagent in which silver ion or silver acetic ion and iron hydroxide precipitation or ferrite ion coexist is added therein. The urea is treated to have a sufficient alkaline, after which it is introduced into a basket type centrifuge formed with a filter layer in combination of an upper glass fiber layer and a lower active carbon layer. The treating agent can uniformly remove radioactive ion and radioactive chelate within urea containing inorganic salt and various metabolites. (Nakamura, S.)

Investigation of some urea derivatives under in vitro conditions

Energy Technology Data Exchange (ETDEWEB)

Goersch, R; Bergner, H [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin

1978-10-01

The protein synthesis from urea, isobutylidene diurea (IBDU), acetyl urea and urea phosphate was investigated in vitro under standardized conditions. The /sup 35/S incorporation into the trichloroacetic acid precipitable fraction of the fermentation mixture and the NH/sub 3/ level served as test criteria. If rumen juice of donor animals adapted to urea was used (test 1), only IBDU made possible a protein synthesis comparable to the urea preparation. Under conditions of IBDU adaption of the donor animals (test 2), urea, IBDU and urea phosphate proved to be of equal value. Acetyl urea showed considerably lower incorporation ratios, irrespective of the adaption of the donor animals.

Investigation of some urea derivatives under in vitro conditions

International Nuclear Information System (INIS)

Goersch, R.; Bergner, H.

1978-01-01

The protein synthesis from urea, isobutylidene diurea (IBDU), acetyl urea and urea phosphate was investigated in vitro under standardized conditions. The 35 S incorporation into the trichloroacetic acid precipitable fraction of the fermentation mixture and the NH 3 level served as test criteria. If rumen juice of donor animals adapted to urea was used (test 1), only IBDU made possible a protein synthesis comparable to the urea preparation. Under conditions of IBDU adaption of the donor animals (test 2), urea, IBDU and urea phosphate proved to be of equal value. Acetyl urea showed considerably lower incorporation ratios, irrespective of the adaption of the donor animals. (author)

Analysis of the stability of urea in dried blood spots collected and stored on filter paper.

Science.gov (United States)

Quraishi, Rizwana; Lakshmy, Ramakrishnan; Mukhopadhyay, Ashok Kumar; Jailkhani, Bansi Lal

2013-05-01

The ability to use dry blood spots (DBSs) on filter paper for the analysis of urea levels could be an important diagnostic tool for areas that have limited access to laboratory facilities. We developed a method for the extraction and quantification of urea from DBSs that were stored on 3M Whatman filter paper and investigated the effect of long-term storage on the level of urea in DBSs. DBSs of 4.5 mm in diameter were used for our assay, and we determined the urea levels in blood using a commercially available enzymatic kit (UV GLDH-method; Randox laboratories Ltd., UK). The DBSs on filter discs were stored at 4℃ or at 37℃ for 120 days. The mean intra- and inter-assay coefficient of variance for our method of urea extraction from dried blood was 4.2% and 6.3%, respectively. We collected 75 fresh blood samples and compared the urea content of each fresh sample with the urea content of DBSs taken from corresponding fresh blood samples. Regression analysis reported a regression coefficient (r) value of 0.97 and a recovery of urea from dried spots was 102.2%. Urea concentrations in DBSs were stable for up to 120 and 90 days when stored at 4℃ and 37℃, respectively. Our results show that urea can be stored and quantitatively recovered from small volumes of blood that was collected on filter paper.

National Urea Cycle Disorders Foundation

Science.gov (United States)

... urea cycle disorders. Donate Now To End Urea Cycle Disorders © 2005-2017 NUCDF. All rights reserved. This site may be freely linked to but not copied or duplicated in any fashion without the Foundation's consent. Make A Donation in ...

Urea concentration in sheep’s milk

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Jasmina Havranek

2009-03-01

Full Text Available Determining urea concentration in milk is a useful indicator for controlling supply of proteins to organisms, as well as the relationship of energy and protein in the food, thus it is finding more and more ways of practical use. The concentration of urea in milk, along with the feeding process, is influenced by a number of other factors such as: breed, stage and sequence of lactation, body mass, daily production and chemical structure of milk, number of somatic cells, season, milking.The goal of the research was to establish the influence of the breed (Island of Krk, East Frisian, lactation stage (beginning, middle and the end and the herd (3 to the concentration of urea in milk during lactation.For each breed there has been established daily quantity of milk, protein share and the concentration of urea in milk.Statistical analysis of data was conducted by using General Linear Models procedure, SAS program system (1999.The breed of sheep considerably (P<0.001 influenced daily quantity of milk, protein share and the concentration of urea in the milk.East Frisian sheep produced on average almost double the daily quantities of milk (1070 mL compared to the Krk sheep (588 mL.Protein share and the urea concentration in Krk sheep milk were higher (5.99 % and 35.97 mg/100 mL then in the milk of East Frisian sheep (5.12 % and 33.31 mg/100 mL.For both breeds the significant influence of lactation stage to the daily milk quantity has been established (0.001, that is also for the urea concentration in the milk of Krk sheep (0.001, as well as protein share in the milk of East Frisian sheep (0.001.Herd influence significantly affected daily milk quantities (0.001 and concentration of urea in the milk (0.05.The defining of the urea concentration in sheep milk should be occasionally carried out in the Republic of Croatia to establish the standard physiological values typical for the particular sheep breed.

40 CFR 721.9925 - Aminoethylethylene urea methacrylamide.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aminoethylethylene urea methacrylamide... Substances § 721.9925 Aminoethylethylene urea methacrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aminoethylethylene urea...

Self-regulation strategies may enhance the acute effect of exercise on smoking delay.

Science.gov (United States)

Hatzigeorgiadis, Antonis; Pappa, Vassiliki; Tsiami, Anastasia; Tzatzaki, Theodora; Georgakouli, Kalliopi; Zourbanos, Nikos; Goudas, Marios; Chatzisarantis, Nikos; Theodorakis, Yannis

2016-06-01

The present study examined the acute effect of a moderate intensity aerobic exercise session combined with self-regulation on smoking delay in physically inactive smokers. Participants were 11 adults (5 males and 6 females) that completed three experimental conditions: control, exercise, and exercise using self-regulation strategies (SR). Following the experimental treatment smoking for the two exercise conditions delayed significantly more than for the control condition; in addition exercise SR delayed smoking marginally more that the plain exercise condition. Findings supported previous research that acute exercise reduces cravings to smoke, and suggests that the use of self-regulation strategies may strengthen exercise for smoking cessation interventions. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

Banchorndhevakul, Siriwattana

2002-01-01

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

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

Science.gov (United States)

Banchorndhevakul, Siriwattana

2002-08-01

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

21 CFR 862.1770 - Urea nitrogen test system.

Science.gov (United States)

2010-04-01

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

Porous Cross-Linked Polyimide-Urea Networks

Science.gov (United States)

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

2015-01-01

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

Transfer of blood urea into the goat colon

International Nuclear Information System (INIS)

Engelhardt, W. von; Hinderer, S.

1976-01-01

Transfer of body urea into the temporarily isolated and perfused colon of conscious goats was measured. Simultaneously total urea turnover was estimated using 14 C-urea. The transfer of urea into the total gastrointestinal tract (total turnover minus renal excretion) was four times higher with the high-energy - low-protein diet (sugar pulp plus straw) compared with control feeding (hay ad lib.). The transfer of urea into the colon was 8% of the transfer into the total GI tract during control feeding, 14% when food was withheld for 48 hours and 1% during sugar pulp feeding. The transfer into the colon depends mainly on the plasma urea concentration, whereas in the proximal part of the GI tract changes in the permeability of the GI tract wall have a more pronounced influence than plasma urea concentration. (author)

Selection of a plant location - A case study: Urea production using ...

African Journals Online (AJOL)

Selection of a plant location - A case study: Urea production using Calub Gas. ... The criteria are. amongst others, supply of raw materials and fuel, market proximity, water supply. waste ... To set up · critical factors for Ethiopian scenario

The fate of ingested [sup 14]C-urea in the urea breath test for Helicobacter pylori infection

Energy Technology Data Exchange (ETDEWEB)

Munster, D J; Chapman, B A; Burt, M J; Dobbs, B R; Allardyce, R A; Bagshaw, P F; Troughton, W D; Cook, H B [Christchurch Hospital (New Zealand)

1993-08-01

The metabolic fate of the radioactive carbon in the [sup 14]C-urea breath test for Helicobacter pylori was investigated in 18 subjects. After ingestion of labelled urea, breath was sampled for 24 h, and urine was collected for 3 days. Subjects were designated high or low expirers on the basis of their breath counts, and this agreed well with H. pylori serologic analyses. When given 185 or 37 kBq of [sup 14]C-urea, 51% of the label was recovered from the breath of high expirers, and 7% from the breath of low expirers. The mean combined urinary and breath recovery for high expirers was 86%, and for low expirers it was 97%. It is concluded that the long-term retention of [sup 14]C from ingested [sup 14]C-urea is low. The results enable a more accurate estimation to be made of radiation exposure resulting from the [sup 14]C-urea breath test. 16 refs., 3 figs., 2 tabs.

Localization and regulation of a facilitative urea transporter in the kidney of the red-eared slider turtle (Trachemys scripta elegans).

Science.gov (United States)

Uchiyama, Minoru; Kikuchi, Ryosuke; Konno, Norifumi; Wakasugi, Tatsuya; Matsuda, Kouhei

2009-01-01

Urea is the major excretory end product of nitrogen metabolism in most chelonian reptiles. In the present study, we report the isolation of a 1632 base pair cDNA from turtle kidney with one open reading frame putatively encoding a 403-residue protein, the turtle urea transporter (turtle UT). The first cloned reptilian UT has high homology with UTs (facilitated urea transporters) cloned from vertebrates, and most closely resembles the UT-A subfamily. Injection of turtle UT cRNA into Xenopus oocytes induced a 6-fold increase in [(14)C]urea uptake that was inhibited by phloretin. The turtle UT mRNA expression and tissue distribution were examined by RT-PCR with total RNA from various tissues. Expression of turtle UT mRNA was restricted to the kidney, and no signal was detected in the other tissues, such as brain, heart, alimentary tract and urinary bladder. An approximately 58 kDa protein band was detected in membrane fractions of the kidney by western blot using an affinity-purified antibody that recognized turtle UT expressed in Xenopus oocytes. In an immunohistochemical study using the anti-turtle UT antibody, UT-immunopositive cells were observed along the distal tubule but not in the collecting duct. In turtles under dry conditions, plasma osmolality and urea concentration increased, and using semi-quantitative RT-PCR the UT mRNA expression level in the kidney was found to increase 2-fold compared with control. The present results, taken together, suggest that the turtle UT probably contributes to urea transport in the distal tubule segments of the kidney in response to hyperosmotic stress under dry conditions.

GC-MS DETERMINATION OF RATIOS OF STABLE-ISOTOPE LABELED TO NATURAL UREA USING [(CN2)-C-13-N-15]UREA FOR STUDYING UREA KINETICS IN SERUM AND AS A MEANS TO VALIDATE ROUTINE METHODS FOR THE QUANTITATIVE ASSAY OF UREA IN DIALYSATE

NARCIS (Netherlands)

WOLTHERS, BG; TEPPER, T; WITHAG, A; NAGEL, GT; DEHAAN, THY; VANLEEUWEN, JJ; STEGEMAN, CA; HUISMAN, RM

A GC-MS determination of urea in serum or spent dialysate is described, using (CN2)-C-13-N-15-labelled urea and assaying the area ratio of labelled to natural urea by mass fragmentographic monitoring of fragments m/e 153 and 156, after its eventual conversion into the trimethylsilylether-derivative

The effects of urea and n-propanol on collagen denaturation: using DSC, circular dicroism and viscosity

International Nuclear Information System (INIS)

Usha, R.; Ramasami, T.

2004-01-01

The effect of urea and n-propanol on circular dichroism (CD) and viscosity of purified type1 collagen solution at various temperatures and differential scanning calorimetry (DSC) of rat-tail tendon (RTT) collagen fibre have been studied. CD reveals a spectrum with a positive peak at around 220 nm and a negative peak at 200 nm characteristics of collagen triple helix. The molar ellipticity decreases as the concentration of urea increases up to particular concentration (collagen solution treated with 265 μM of urea) and after that it increases (collagen solution treated with 500 μM of urea). There is a linear decrease in molar ellipticity as the concentration of n-propanol increases. Denaturation temperature of urea and n-propanol treated with purified collagen solution has been studied using viscosity method. Additives such as urea and n-propanol decrease the thermal stability of collagen triple helix in solution and in RTT collagen fibre. Thermal helix to coil transition of urea and n-propanol treated collagen depends on the degree of hydration and the concentration of these additives. Thermodynamic parameters such as the peak temperature, enthalpy of activation, and energy of activation for collagen-gelatin transition for native, urea and n-propanol treated RTT collagen fibre has been calculated using DSC. The change in the thermodynamic parameters has been observed for native, urea and n-propanol treated RTT collagen fibres. The experimental results show that the change in the water structure, dehydration and desolvation induced by different additives such as urea and n-propanol on RTT may vary with the type of denaturation

Review on Carbon Dioxide Absorption by Choline Chloride/Urea Deep Eutectic Solvents

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Rima J. Isaifan

2018-01-01

Full Text Available In the recent past few years, deep eutectic solvents (DESs were developed sharing similar characteristics to ionic liquids but with more advantageous features related to preparation cost, environmental impact, and efficiency for gas separation processes. Amongst many combinations of DES solvents that have been prepared, reline (choline chloride as the hydrogen bond acceptor mixed with urea as the hydrogen bond donor was the first DES synthesized and is still the one with the lowest melting point. Choline chloride/urea DES has proven to be a promising solvent as an efficient medium for carbon dioxide capture when compared with amine alone or ionic liquids under the same conditions. This review sheds light on the preparation method, physical and chemical characteristics, and the CO2 absorption capacity of choline chloride/urea DES under different temperatures and pressures reported up to date.

Potentiometric Urea Biosensor Based on an Immobilised Fullerene-Urease Bio-Conjugate

Directory of Open Access Journals (Sweden)

Kasra Saeedfar

2013-12-01

Full Text Available A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed electrode containing a non-plasticized poly(n-butyl acrylate (PnBA membrane entrapped with a hydrogen ionophore. This pH-selective membrane is intended to function as a potentiometric urea biosensor with the deposition of C60-urease on the PnBA membrane. Various parameters for fullerene modification and urease immobilization were investigated. The optimal pH and concentration of the phosphate buffer for the urea biosensor were 7.0 and 0.5 mM, respectively. The linear response range of the biosensor was from 2.31 × 10−3 M to 8.28 × 10−5 M. The biosensor’s sensitivity was 59.67 ± 0.91 mV/decade, which is close to the theoretical value. Common cations such as Na+, K+, Ca2+, Mg2+ and NH4+ showed no obvious interference with the urea biosensor’s response. The use of a fullerene-urease bio-conjugate and an acrylic membrane with good adhesion prevented the leaching of urease enzyme and thus increased the stability of the urea biosensor for up to 140 days.

Utilization of urea-nitrogen-15 in ruminants

International Nuclear Information System (INIS)

Boda, K.; Varady, J.; Havassy, I.

1976-01-01

In Merino sheep a series of experiments were carried out investigating exogenous and endogenous urea utilization. On the experimental sheep with isolated jejunum, rumen and intestine fistula, re-entral intestine cannulae, and after intra-ruminal or intra-intestinal 15 N-urea administration it was found that urea- 15 N takes part in the nitrogen recycling, and is utilized in the nitrogen pool. In experiments with synthetic protein-free diet, low protein diet and high nitrogen diet, after the intravenous administration of 15 N-urea the following findings were made: The results of experiments with synthetic diet, where the only nitrogen source was perorally (for 3-6 months) and then intravenously (for 3 months) administered urea, indicated the ability of ruminants to replace fully the nitrogen in the feed under certain conditions by increased endogenous urea recirculation. The results of the experiments with various nitrogen intakes showed that considerable amounts of urea- 15 N (44-96% from the given dose) were retained. Nitrogen compounds synthetized from blood urea- 15 N were recycled through the alimentary tract. Its secretion predominated in the forestomachs, abomasum and duodenum, and its reabsorption took place in the intestinal tract. From the 15 N incorporated into the nitrogenous substances which passed through the duodenum, 73-84% was reabsorbed. The retained 15 N was incorporated into the microbial and plasma proteins and its amide-N. On the basis of these results it is concluded that in addition to the rumeno-hepatal circulation, the entero-hepatal circulation of nitrogenous substances, including endogenous nitrogen, also plays an important role quantitatively and perhaps qualitatively in the process of re-utilizing the blood urea N for proteosynthesis and synthesis of other N-metabolites in ruminants. The hydrolysis of endogenous urea in the gastro-intestinal tract of ruminants and its utilization is a natural process indispensable for the maintenance of

Maesopsin 4-O-beta-D-glucoside, a natural compound isolated from the leaves of Artocarpus tonkinensis, inhibits proliferation and up-regulates HMOX1, SRXN1 and BCAS3 in acute myeloid leukemia.

Science.gov (United States)

Pozzesi, N; Pierangeli, S; Vacca, C; Falchi, L; Pettorossi, V; Martelli, M P; Thuy, T T; Ninh, P T; Liberati, A M; Riccardi, C; Sung, T V; Delfino, D V

2011-06-01

The leaves of Artocarpus tonkinensis are used in Vietnamese traditional medicine for treatment of arthritis, and the compound maesopsin 4-O-β-D-glucoside (TAT-2), isolated from them, inhibits the proliferation of activated T cells. Our goal was to test the anti-proliferative activity of TAT-2 on the T-cell leukemia, Jurkat, and on the acute myeloid leukemia, OCI-AML. TAT-2 inhibited the growth of OCI-AML (and additional acute myeloid leukemia cells) but not Jurkat cells. Growth inhibition was shown to be due to inhibition of proliferation rather than increase in cell death. Analysis of cytokine release showed that TAT-2 stimulated the release of TGF-β, yet TGF-β neutralization did not reverse the maesopsin-dependent effect. Gene expression profiling determined that maesopsin modulated 19 identifiable genes. Transcription factor CP2 was the gene most significantly modulated. Real-time PCR validated that up-regulation of sulphiredoxin 1 homolog (SRXN1), hemeoxygenase 1 (HMOX1), and breast carcinoma amplified sequence 3 (BCAS3) were consistently modulated.

Diffusion Kurtosis Imaging of Acute Infarction: Comparison with Routine Diffusion and Follow-up MR Imaging.

Science.gov (United States)

Yin, Jianzhong; Sun, Haizhen; Wang, Zhiyun; Ni, Hongyan; Shen, Wen; Sun, Phillip Zhe

2018-05-01

Purpose To determine the relationship between diffusion-weighted imaging (DWI) and diffusion kurtosis imaging (DKI) in patients with acute stroke at admission and the tissue outcome 1 month after onset of stroke. Materials and Methods Patients with stroke underwent DWI (b values = 0, 1000 sec/mm 2 along three directions) and DKI (b values = 0, 1000, 2000 sec/mm 2 along 20 directions) within 24 hours after symptom onset and 1 month after symptom onset. For large lesions (diameter ≥ 1 cm), acute lesion volumes at DWI and DKI were compared with those at follow-up T2-weighted imaging by using Spearman correlation analysis. For small lesions (diameter the number of acute lesions at DWI and DKI and follow-up T2-weighted imaging was counted and compared by using the McNemar test. Results Thirty-seven patients (mean age, 58 years; range, 35-82 years) were included. There were 32 large lesions and 138 small lesions. For large lesions, the volumes of acute lesions on kurtosis maps showed no difference from those on 1-month follow-up T2-weighted images (P = .532), with a higher correlation coefficient than those on the apparent diffusion coefficient and mean diffusivity maps (R 2 = 0.730 vs 0.479 and 0.429). For small lesions, the number of acute lesions on DKI, but not on DWI, images was consistent with that on the follow-up T2-weighted images (P = .125). Conclusion DKI complements DWI for improved prediction of outcome of acute ischemic stroke. © RSNA, 2018.

Variation of milk urea in dairy cattle : a study on factors that affect the relationship between urea concentration in milk and urea excretion in urine

NARCIS (Netherlands)

Spek, J.W.

2013-01-01

The aim of this thesis was to increase the applicability of milk urea nitrogen concentration (MUN) as a predictor of urinary urea nitrogen excretion (UUN) by identifying and quantifying factors that can explain variation in MUN that is not related to UUN. A literature study was conducted in

Carcass characteristics of sheep fed diets with slow-release urea replacing conventional urea

Directory of Open Access Journals (Sweden)

Evanilton Moura Alves

2014-07-01

Full Text Available This study aimed to evaluate the effects of adding slow-release urea to replace conventional urea in the diet on carcass characteristics of feedlot sheep. We used 20 Santa Ines x SRD rams, with average body weight of 21.1±1.2 kgand average age of 120 days, distributed in a completely randomized design with 5 treatments. The replacement levels used as treatments were 0, 20, 40, 60, and 80%, composing diets of about 12% crude protein, with 50 % Tifton-85 hay and 50% concentrate. There was no influence of slow release urea on weight at slaughter (35.17 kg, and on hot (16.75 kg and cold (16.24 kg carcass weight, but the yield of these carcasses showed quadratic trend, revealing lower percentages at 48.5 and 47.63% replacement levels, respectively. The weights and yields of cuts did not change, except for the posterior arm, whose values showed a cubic trend. Objective measures of carcass, loin eye area, and subjective evaluations of conformation, finishing and marbling of carcasses were not affected. The subcutaneous fat thickness decreased linearly (4.25 to2.48 mm. The inclusion of slow release urea in the diet changes the yield and reduces subcutaneous fat, however, it does not influence other carcass characteristics.

Silencing of microRNA-155 in mice during acute inflammatory response leads to derepression of c/ebp Beta and down-regulation of G-CSF

DEFF Research Database (Denmark)

Worm, Jesper; Stenvang, Jan; Petri, Andreas

2009-01-01

microRNA-155 (miR-155) has been implicated as a central regulator of the immune system, but its function during acute inflammatory responses is still poorly understood. Here we show that exposure of cultured macrophages and mice to lipopolysaccharide (LPS) leads to up-regulation of miR-155......-stimulating factor (G-CSF), a central regulator of granulopoiesis during inflammatory responses. Consistent with these data, we show that silencing of miR-155 in LPS-treated mice by systemically administered LNA-antimiR results in derepression of the c/ebp Beta isoforms and down-regulation of G-CSF expression...

Urea-assisted liquid-phase exfoliation of natural graphite into few-layer graphene

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Hou, Dandan; Liu, Qinfu; Wang, Xianshuai; Qiao, Zhichuan; Wu, Yingke; Xu, Bohui; Ding, Shuli

2018-05-01

The mass production of graphene with high quality is desirable for its wide applications. Here, we demonstrated a facile method to exfoliate natural graphite into graphene in organic solvent by assisting of urea. The exfoliation of graphite may originate from the "molecular wedge" effect of urea, which can intercalate into the edge of natural graphite, thus facilitating the production of graphene dispersion with a high concentration up to 1.2 mg/mL. The obtained graphene is non-oxidized with negligible defects. Therefore, this approach has great promise in bulk production of graphene with superior quality for a variety of applications.

Dissolution of lignin in green urea aqueous solution

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Wang, Jingyu; Li, Ying; Qiu, Xueqing; Liu, Di; Yang, Dongjie; Liu, Weifeng; Qian, Yong

2017-12-01

The dissolution problem is the main obstacle for the value-added modification and depolymerization of industrial lignin. Here, a green urea aqueous solution for complete dissolution of various lignin is presented and the dissolution mechanism is analyzed by AFM, DLS and NMR. The results show that the molecular interaction of lignin decreases from 32.3 mN/m in pure water to 11.3 mN/m in urea aqueous solution. The immobility of 1H NMR spectra and the shift of 17O NMR spectra of urea in different lignin/urea solutions indicate that the oxygen of carbonyl in urea and the hydrogen of hydroxyl in lignin form new hydrogen bonds and break the original hydrogen bonds among lignin molecules. The shift of 1H NMR spectra of lignin and the decrease of interactions in model compound polystyrene indicate that urea also breaks the π-π interactions between aromatic rings of lignin. Lignin dissolved in urea aqueous has good antioxidant activity and it can scavenge at least 63% free radicals in 16 min.

Cystatin C as an early marker of acute kidney injury in septic shock.

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Ortuño-Andériz, F; Cabello-Clotet, N; Vidart-Simón, N; Postigo-Hernández, C; Domingo-Marín, S; Sánchez-García, M

2015-03-01

To describe the utility of determining plasma cystatinC concentrations in the diagnosis of acute incident kidney injury in septic shock. Prospective series of 50 patients with septic shock and plasma creatinine levels <2mg/dL hospitalized in an intensive care unit. Clinical and laboratory follow-ups were conducted, with measurements of cystatinC, urea and plasma creatinine levels from the diagnosis of septic shock to 5days later. The severity of the septic shock was assessed with the RIFLE scale. Twenty patients (40%) developed acute kidney injury: 8 (16%) were categorized as RIFLE-R, 5 (10%) as RIFLE-I and 7 (14%) as RIFLE-F. All patients categorized as RIFLE-F required extracorporeal renal clearance. Eighteen (36%) patients died, 8 (20%) of whom had developed acute kidney injury in their evolution. There was poor correlation between plasma creatinine and cystatin C levels (r=.501; P=.001), which disappeared upon reaching any degree of renal impairment on the RIFLE scale. CystatinC levels increased earlier and were better able to identify patients who would develop serious renal function impairment (RIFLE-F) than creatinine and urea levels. The initial cystatinC levels were related to mortality at 30days (OR=1.16; 95%CI: 03-.85). For patients who developed acute septic kidney injury, the plasma cystatinC levels increased before the classical markers of renal function. CystatinC also constitutes a severity biomarker that correlates with progression to RIFLE-F, the need for extrarenal clearance and, ultimately, mortality. This precocity could be useful for starting measures that prevent the progression of renal dysfunction. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

Rapamycin up-regulates triglycerides in hepatocytes by down-regulating Prox1.

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Kwon, Sora; Jeon, Ji-Sook; Kim, Su Bin; Hong, Young-Kwon; Ahn, Curie; Sung, Jung-Suk; Choi, Inho

2016-02-27

Although the prolonged use of rapamycin may cause unwanted side effects such as hyperlipidemia, the underlying mechanism remains unknown. Prox1 is a transcription factor responsible for the development of several tissues including lymphatics and liver. There is growing evidences that Prox1 participates in metabolism in addition to embryogenesis. However, whether Prox1 is directly related to lipid metabolism is currently unknown. HepG2 human hepatoma cells were treated with rapamycin and total lipids were analyzed by thin layer chromatography. The effect of rapamycin on the expression of Prox1 was determined by western blotting. To investigate the role of Prox1 in triglycerides regulation, siRNA and overexpression system were employed. Rapamycin was injected into mice for 2 weeks and total lipids and proteins in liver were measured by thin layer chromatography and western blot analysis, respectively. Rapamycin up-regulated the amount of triglyceride and down-regulated the expression of Prox1 in HepG2 cells by reducing protein half-life but did not affect its transcript. The loss-of-function of Prox1 was coincident with the increase of triglycerides in HepG2 cells treated with rapamycin. The up-regulation of triglycerides by rapamycin in HepG2 cells reverted to normal levels by the compensation of Prox1 using the overexpression system. Rapamycin also down-regulated Prox1 expression but increased triglycerides in mouse liver. This study suggests that rapamycin can increase the amount of triglycerides by down-regulating Prox1 expression in hepatocytes, which means that the mammalian target of rapamycin (mTOR) signaling is important for the regulation of triglycerides by maintaining Prox1 expression.

Down-regulated miR-448 relieves spinal cord ischemia/reperfusion injury by up-regulating SIRT1

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Yun Wang

2018-03-01

Full Text Available MicroRNAs play a crucial role in the progression of spinal cord ischemia/reperfusion injury (SCII. The role of miR-448 and SIRT1 in SCII was investigated in this study, to provide further insights into prevention and improvement of this disorder. In this study, expressions of miR-448 and SIRT1 protein were determined by qRT-PCR and western blot, respectively. Flow cytometry was used to analyze cell apoptosis. The endogenous expression of genes was modulated by recombinant plasmids and cell transfection. Dual-luciferase reporter assay was performed to determine the interaction between miR-448 and SIRT1. The Basso, Beattie, and Bresnahan score was used to measure the hind-limb function of rat. The spinal cord ischemia reperfusion injury model of adult rats was developed by abdominal aorta clamping, and the nerve function evaluation was completed by motor deficit index score. In SCII tissues and cells treated with hypoxia, miR-448 was up-regulated while SIRT1 was down-regulated. Hypoxia treatment reduced the expression of SIRT1 through up-regulating miR-448 in nerve cells. Up-regulation of miR-448 induced by hypoxia promoted apoptosis of nerve cells through down-regulating SIRT1. Down-regulated miR-448 improved neurological function and hind-limb motor function of rats with SCII by up-regulating SIRT1. Down-regulated miR-448 inhibited apoptosis of nerve cells and improved neurological function by up-regulating SIRT1, which contributes to relieving SCII.

N-Urea Efficiency In Lowland Rice Applied With Azolla

International Nuclear Information System (INIS)

Rasjid, Havid; Sisworo, E.L.; Wemay, Y.; Sisworo, W.H.

2000-01-01

Two N-fertilizer experiments have been conducted using urea tablet and prill urea combined with Azolla application. Twelve treatments have been tested using 2 rice varieties namely Atomita-4 and IR-64. To enable the determination of N-urea efficiency 15 N labelled urea was used. The experiments were conducted in the dry and wet season (DS and WS) 1994/1995 at the experimental station, pusaka negara, Subang West Java. Data obtained from the two experiments showed that the highest N-urea efficiency was found in Atomita-4 applied with urea-tablet (DS=46,1%, WS= 35,8%). Letting the Azolla grow during one lowland rice growth period could increase the N-urea prill efficiency (±5%) compared when no azolla was applied. Apparently Atomita-4 could use N-urea more efficiently compared to IR-64, showing higher grain yield (atomita-4 DS=6.2 ton ha -1 WS=5.9 ton ha -1 ) vs IR-64 (DS=5.8 ton ha -1 , WS=5.3 ton ha -1 ). Decreasing the levels of TSP not influence to the urea efficiency at the DS and WS

Measurement of synovial fluid volume using urea.

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Kraus, V B; Stabler, T V; Kong, S Y; Varju, G; McDaniel, G

2007-10-01

To examine the utility of using urea concentrations for determining Synovial Fluid (SF) joint volume in effused and non-effused joints. Knee joint SF was aspirated from 159 human study participants with symptomatic osteoarthritis of at least one knee either directly (165 knees) or by lavage (110 knees). Serum was obtained immediately prior to SF aspiration. Participants were asked to rate individual knee pain, aching or stiffness. SF and serum urea levels were determined using a specific enzymatic method run on an automated CMA600 analyzer. Cell counts were performed on direct SF aspirates when volume permitted. The formula for calculating SF joint volume was as follows: V(j)=C(D)(V(I))/(C-C(D)) with V(j)=volume of SF in entire joint, C(D)=concentration of urea in diluted (lavage) SF, V(I)=volume of saline injected into joint, and C=concentration of urea in undiluted (neat) SF derived below where C=0.897(C(S)) and C(s)=concentration of urea in serum. There was an excellent correlation (r(2)=0.8588) between SF and serum urea in the direct aspirates with a ratio of 0.897 (SF/serum). Neither urea levels nor the SF/serum ratio showed any correlation with Kellgren Lawrence (KL) grade, or cell count. While urea levels increased with age there was no change in the ratio. Intraarticular SF volumes calculated for the lavaged knees ranged from 0.555 to 71.71ml with a median volume of 3.048ml. There was no correlation of SF volume to KL grade but there was a positive correlation (P=0.001) between SF volume and self-reported individual knee pain. Our urea results for direct aspirates indicate an equilibrium state between serum and SF with regard to the water fraction. This equilibrium exists regardless of disease status (KL grade), inflammation (cell count), or age, making it possible to calculate intraarticular volume of lavaged joints based upon this urea method. Most of the joint volumes we calculated fell within the previously reported range for normal knees of 0.5-4.0ml

Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas.

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

2005-10-01

Plasma urea levels and hepatic urea production in the euryhaline bull shark, Carcharhinus leucas, acclimated to freshwater and seawater environments were measured. It was found that plasma urea concentration increased with salinity and that this increase was, in part, the result of a significant increase in hepatic production of urea. This study provides direct evidence that hepatic production of urea plays an important role in the osmoregulatory strategy of C. leucas. (c) 2005 Wiley-Liss, Inc.

Urea utilization in protein deficient rats

Energy Technology Data Exchange (ETDEWEB)

Tanaka, N [Hyogo College of Medicine, Nishinomiya, Hyogo (Japan)

1982-06-01

Three experiments were performed to investigate the mechanism of urea utilization and the nutritional roles of intestinal flora on the utilization of urea by rats fed with a protein deficient diet. Ammonia content in the small intestine in LPD(low protein diet) group fed with a low protein diet for 2 or 5 weeks was about three of five times higher than that of control group fed with SPD(standard protein diet) after administration of urea (0.2gN/100gB.W.). The /sup 15/N incorporation into plasma protein of LPD group was significantly higher than that of the control group two hours after the administration of /sup 15/N-urea (10 mg/100gB.W.) and higher level of /sup 15/N concentration in plasma protein in LPD group was maintained thereafter. The /sup 15/N incorporation into the amino acids of plasma protein was higher in LPD group than in control group. The /sup 15/N incorporation into the amino acids in portal plasma seemed to be higher in LPD group than in control group one hour after the administration of /sup 15/N-urea (10mg/100gB.W.). However, the /sup 15/N incorporation into each free amino acids was suppressed considerably by the administration of antibiotic mixture. it follows that amino acids may be synthesized from urea in the intestine by intestinal-bacterial action and absorbed from portal vein. From these results, it may be concluded that the ammonia nitrogen converted from urea by the action of intestinal-bacterial urease in the intestine is utilized for the synthesis of essential and nonessential amino acids in protein deficient rats and transfered to the liver through portal vein and utilized for protein synthesis.

Urea utilization in protein deficient rats

International Nuclear Information System (INIS)

Tanaka, Noriko

1982-01-01

Three experiments were performed to investigate the mechanism of urea utilization and the nutritional roles of intestinal flora on the utilization of urea by rats fed with a protein deficient diet. Ammonia content in the small intestine in LPD(low protein diet) group fed with a low protein diet for 2 or 5 weeks was about three of five times higher than that of control group fed with SPD(standard protein diet) after administration of urea (0.2gN/100gB.W.). The 15 N incorporation into plasma protein of LPD group was significantly higher than that of the control group two hours after the administration of 15 N-urea (10 mg/100gB.W.) and higher level of 15 N concentration in plasma protein in LPD group was maintained thereafter. The 15 N incorporation into the amino acids of plasma protein was higher in LPD group than in control group. The 15 N incorporation into the amino acids in portal plasma seemed to be higher in LPD group than in control group one hour after the administration of 15 N-urea (10mg/100gB.W.). However, the 15 N incorporation into each free amino acids was suppressed considerably by the administration of antibiotic mixture. it follows that amino acids may be synthesized from urea in the intestine by intestinal-bacterial action and absorbed from portal vein. From these results, it may be concluded that the ammonia nitrogen converted from urea by the action of intestinal-bacterial urease in the intestine is utilized for the synthesis of essential and nonessential amino acids in protein deficient rats and transfered to the liver through portal vein and utilized for protein synthesis. (J.P.N.)

Hardness evaluation of cured urea-formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

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Byung-Dae Park; Charles R. Frihart; Yan Yu; Adya P. Singh

2013-01-01

To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (HB) method was also used...

Effect of rumen-degradable intake protein supplementation on urea kinetics and microbial use of recycled urea in steers consuming low-quality forage.

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Wickersham, T A; Titgemeyer, E C; Cochran, R C; Wickersham, E E; Gnad, D P

2008-11-01

We evaluated the effect of increasing amounts of rumen-degradable intake protein (DIP) on urea kinetics in steers consuming prairie hay. Ruminally and duodenally fistulated steers (278 kg of BW) were used in a 4 x 4 Latin square and provided ad libitum access to low-quality prairie hay (4.9% CP). The DIP was provided as casein dosed ruminally once daily in amounts of 0, 59, 118, and 177 mg of N/kg of BW daily. Periods were 13 d long, with 7 d for adaptation and 6 d for collection. Steers were in metabolism crates for total collection of urine and feces. Jugular infusion of (15)N(15)N-urea, followed by determination of urinary enrichment of (15)N(15)N-urea and (14)N(15)N-urea was used to determine urea kinetics. Forage and N intake increased (linear, P Urea synthesis was 19.9, 24.8, 42.9, and 50.9 g of urea-N/d for 0, 59, 118, and 177 mg of N/kg of BW daily (linear, P = 0.004). Entry of urea into the gut was 98.9, 98.8, 98.6, and 95.9% of production for 0, 59, 118, and 177 mg of N/kg of BW daily, respectively (quadratic, P = 0.003). The amount of urea-N entering the gastrointestinal tract was greatest for 177 mg of N/kg of BW daily (48.6 g of urea-N/d) and decreased (linear, P = 0.005) to 42.4, 24.5, and 19.8 g of urea-N/d for 118, 59, and 0 mg of N/kg of BW daily. Microbial incorporation of recycled urea-N increased linearly (P = 0.02) from 12.3 g of N/d for 0 mg of N/kg of BW daily to 28.9 g of N/d for 177 mg of N/kg of BW daily. Provision of DIP produced the desired and previously observed increase in forage intake while also increasing N retention. The large percentage of urea synthesis that was recycled to the gut (95.9% even when steers received the greatest amount of DIP) points to the remarkable ability of cattle to conserve N when fed a low-protein diet.

Reduction of nitrogen oxides by injection of urea in the freeboard of a pilot scale fluidized bed combustor

NARCIS (Netherlands)

Knol, Koen E.; Bramer, Eduard A.; Valk, M.

1989-01-01

The ‘thermal deNOx’ process using urea has been investigated in a 1 MW fluidized bed combustor. NOx reductions of up to 76% were obtainable by using this method. The experimental results show that urea is at least as active as NH3, which is commonly used in this application, but which is far more

Synthesis of 15N-labelled urea and methylenediurea

International Nuclear Information System (INIS)

Murray, T.P.; Jones, G.T.

1985-01-01

A new technique was developed for the large-scale synthesis of 15 N-labelled urea at low enrichment levels. The synthesis is based on nucleophilic displacement of the phenoxide ion from phenyl carbonate and uses anhydrous ammonia as the nucleophile. In previous reports a copper catalyst was used; however, in this study it was found that the copper resulted in product decomposition and tar formation, which makes product purification difficult. A novel set of reaction conditions was developed: no catalyst was used, and no product decomposition or tar formation occurred. The reaction product was easily purified, and consistently high yields of 15 N-labelled urea were obtained. 15 N-labelled methylenediurea was prepared by the dilute solution reaction of formalin with 15 N-labelled urea. The methodology developed for the reclamation of unreacted urea resulted in minimum loss of labelled urea. High performance liquid chromatography has been used to determine the chemical purity of both urea and methylenediurea. (author)

Modelling and mutational analysis of Aspergillus nidulans UreA, a member of the subfamily of urea/H+ transporters in fungi and plants

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Sanguinetti, Manuel; Amillis, Sotiris; Pantano, Sergio; Scazzocchio, Claudio; Ramón, Ana

2014-01-01

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

Entry of blood urea into the rumen of the llama

International Nuclear Information System (INIS)

Hinderer, S.; Engelhardt, W. von

1976-01-01

Llamas were provided with a large rumen fistula, and the transfer of blood urea into the temporarily isolated rumen, cleaned and filled with test solution was measured. Plasma urea clearance due to transfer of blood urea across the rumen wall should indicate changes in its permeability to urea. Clearance values were highest with CO 2 or with high concentrations of butyric acid. Permeability was low when food was with-held and when no volatile fatty acids were present in the solution. The permeability of the rumen wall to blood urea can be altered significantly. These changes can affect blood urea transfer more extensively than changes in the plasma urea concentration within physiological ranges

Minimal sampling protocol for accurate estimation of urea production: a study with oral [13C]urea in fed and fasted piglets

NARCIS (Netherlands)

Oosterveld, Michiel J. S.; Gemke, Reinoud J. B. J.; Dainty, Jack R.; Kulik, Willem; Jakobs, Cornelis; de Meer, Kees

2005-01-01

An oral [13C]urea protocol may provide a simple method for measurement of urea production. The validity of single pool calculations in relation to a reduced sampling protocol was assessed. In eight fed and five fasted piglets, plasma urea enrichments from a 10 h sampling protocol were measured

Survival after treatment with phenylacetate and benzoate for urea-cycle disorders.

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Enns, Gregory M; Berry, Susan A; Berry, Gerard T; Rhead, William J; Brusilow, Saul W; Hamosh, Ada

2007-05-31

The combination of intravenous sodium phenylacetate and sodium benzoate has been shown to lower plasma ammonium levels and improve survival in small cohorts of patients with historically lethal urea-cycle enzyme defects. We report the results of a 25-year, open-label, uncontrolled study of sodium phenylacetate and sodium benzoate therapy (Ammonul, Ucyclyd Pharma) in 299 patients with urea-cycle disorders in whom there were 1181 episodes of acute hyperammonemia. Overall survival was 84% (250 of 299 patients). Ninety-six percent of the patients survived episodes of hyperammonemia (1132 of 1181 episodes). Patients over 30 days of age were more likely than neonates to survive an episode (98% vs. 73%, Purea-cycle disorder and treatment with both sodium phenylacetate and sodium benzoate, in conjunction with other therapies, such as intravenous arginine hydrochloride and the provision of adequate calories to prevent catabolism, effectively lower plasma ammonium levels and result in survival in the majority of patients. Hemodialysis may also be needed to control hyperammonemia, especially in neonates and older patients who do not have a response to intravenous sodium phenylacetate and sodium benzoate. Copyright 2007 Massachusetts Medical Society.

Water-mediated interactions between trimethylamine-N-oxide and urea.

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Hunger, Johannes; Ottosson, Niklas; Mazur, Kamila; Bonn, Mischa; Bakker, Huib J

2015-01-07

The amphiphilic osmolyte trimethylamine-N-oxide (TMAO) is commonly found in natural organisms, where it counteracts biochemical stress associated with urea in aqueous environments. Despite the important role of TMAO as osmoprotectant, the mechanism behind TMAO's action has remained elusive. Here, we study the interaction between urea, TMAO, and water in solution using broadband (100 MHz-1.6 THz) dielectric spectroscopy. We find that the previously reported tight hydrogen bonds between 3 water molecules and the hydrophilic amine oxide group of TMAO, remain intact at all investigated concentrations of urea, showing that no significant hydrogen bonding occurs between the two co-solutes. Despite the absence of direct TMAO-urea interactions, the solute reorientation times of urea and TMAO show an anomalous nonlinear increase with concentration, for ternary mixtures containing equal amounts of TMAO and urea. The nonlinear increase of the reorientation correlates with changes in the viscosity, showing that the combination of TMAO and urea cooperatively enhances the hydrogen-bond structure of the ternary solutions. This nonlinear increase is indicative of water mediated interaction between the two solutes and is not observed if urea is combined with other amphiphilic solutes.

Photo-assisted electrochemical oxidation of the urea onto TiO2-nanotubes modified by hematite

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Waleed M. Omymen

2017-12-01

Full Text Available The electrochemical oxidation of the urea in near neutral pH is investigated on platinum electrode. It is shown that oxidation reaction is practically inhibited up to the potentials of ∼0.9 V. The same reaction is investigated onto electrochemically obtained titanium dioxide nanotubes modified by hematite using facile, low-cost successive ion layer adsorption and reaction (SILAR method. It is shown that such system possesses electrocatalytic activity at very low potentials, and activity can be further improved by the illumination of the electrode in the photo-assisted reaction. The possible application of the photoactive anode is considered in the application of urea based water electrolysis and urea based fuel cell. Keywords: Photoelectrochemical cell, Water electrolysis, Fuel cell, SILAR

Vinpocetine reduces diclofenac-induced acute kidney injury through inhibition of oxidative stress, apoptosis, cytokine production, and NF-κB activation in mice.

Science.gov (United States)

Fattori, Victor; Borghi, Sergio M; Guazelli, Carla F S; Giroldo, Andressa C; Crespigio, Jefferson; Bussmann, Allan J C; Coelho-Silva, Letícia; Ludwig, Natasha G; Mazzuco, Tânia L; Casagrande, Rubia; Verri, Waldiceu A

2017-06-01

Acute kidney injury (AKI) represents a complex clinical condition associated with significant morbidity and mortality. Approximately, 19-33% AKI episodes in hospitalized patients are related to drug-induced nephrotoxicity. Although, considered safe, non-steroidal anti-inflammatory drugs such as diclofenac have received special attention in the past years due to the potential risk of renal damage. Vinpocetine is a nootropic drug known to have anti-inflammatory properties. In this study, we investigated the effect and mechanisms of vinpocetine in a model of diclofenac-induced AKI. We observed that diclofenac increased proteinuria and blood urea, creatinine, and oxidative stress levels 24h after its administration. In renal tissue, diclofenac also increased oxidative stress and induced morphological changes consistent with renal damage. Moreover, diclofenac induced kidney cells apoptosis, up-regulated proinflammatory cytokines, and induced the activation of NF-κB in renal tissue. On the other hand, vinpocetine reduced diclofenac-induced blood urea and creatinine. In the kidneys, vinpocetine inhibited diclofenac-induced oxidative stress, morphological changes, apoptosis, cytokine production, and NF-κB activation. To our knowledge, this is the first study demonstrating that diclofenac-induced AKI increases NF-κB activation, and that vinpocetine reduces the nephrotoxic effects of diclofenac. Therefore, vinpocetine is a promising molecule for the treatment of diclofenac-induced AKI. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efectividad de la pomada de urea en las verrugas plantares Effectiveness of the urea ointment in the feet warts

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Elisa Chacón Eduardo

2009-10-01

Full Text Available Se hizo un ensayo clinicoterapéutico en 60 pacientes atendidos en la consulta de Dermatología del Hospital Provincial Docente “Dr. Joaquín Castillo Duany” de Santiago de Cuba, durante el 2008, con el fin evaluar la efectividad de la pomada de urea en las verrugas plantares. Se conformaron 2 grupos (de estudio y control: los primeros recibieron pomada de urea al 20 % y los segundos pomada salicílica al 40 %. La pomada de urea resultó más eficaz para eliminar las manifestaciones clínicas de esa lesión, en un período de 6 a 8 semanas y no hubo reacciones adversas.A clinical therapeutical trial was made in 60 patients assisted at the Dermatology department of "Dr. Joaquín Castillo Duany" Teaching Provincial Hospital from Santiago de Cuba, during 2008, aimed at evaluating the effectiveness of the urea ointment in the feet warts. They conformed to 2 groups (study and control: the first group received urea ointment at 20% and the second one salicylic ointment at 40%. The urea ointment was more effective to eliminate the clinical manifestations of that lesion, in a period of 6 to 8 weeks and there were not adverse reactions.

Acute and chronic glucocorticoid treatments regulate astrocyte-enriched mRNAs in multiple brain regions in vivo

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Bradley S. Carter

2013-08-01

Full Text Available Previous studies have primarily interpreted gene expression regulation by glucocorticoids in the brain in terms of impact on neurons; however, less is known about the corresponding impact of glucocorticoids on glia and specifically astrocytes in vivo. Recent microarray experiments have identified glucocorticoid-sensitive mRNAs in primary astrocyte cell culture, including a number of mRNAs that have reported astrocyte-enriched expression patterns relative to other brain cell types. Here, we have tested whether elevations of glucocorticoids regulate a subset of these mRNAs in vivo following acute and chronic corticosterone exposure in adult mice. Acute corticosterone exposure was achieved by a single injection of 10 mg/kg corticosterone, and tissue samples were harvested two hours post-injection. Chronic corticosterone exposure was achieved by administering 10 mg/mL corticosterone via drinking water for two weeks. Gene expression was then assessed in two brain regions associated with glucocorticoid action (prefrontal cortex and hippocampus by qPCR and by in situ hybridization. The majority of measured mRNAs regulated by glucocorticoids in astrocytes in vitro were similarly regulated by acute and/or chronic glucocorticoid exposure in vivo. In addition, the expression levels for mRNAs regulated in at least one corticosterone exposure condition (acute/chronic demonstrated moderate positive correlation between the two conditions by brain region. In situ hybridization analyses suggest that select mRNAs are regulated by chronic corticosterone exposure specifically in astroctyes based on (1 similar general expression patterns between corticosterone-treated and vehicle-treated animals and (2 similar expression patterns to the pan-astrocyte marker Aldh1l1. Our findings demonstrate that glucocorticoids regulate astrocyte-enriched mRNAs in vivo and suggest that glucocorticoids regulate gene expression in the brain in a cell type-dependent fashion.

Sustained oxidative stress causes late acute renal failure via duplex regulation on p38 MAPK and Akt phosphorylation in severely burned rats.

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Yafei Feng

Full Text Available BACKGROUND: Clinical evidence indicates that late acute renal failure (ARF predicts high mortality in severely burned patients but the pathophysiology of late ARF remains undefined. This study was designed to test the hypothesis that sustained reactive oxygen species (ROS induced late ARF in a severely burned rat model and to investigate the signaling mechanisms involved. MATERIALS AND METHODS: Rats were exposed to 100°C bath for 15 s to induce severe burn injury (40% of total body surface area. Renal function, ROS generation, tubular necrosis and apoptosis, and phosphorylation of MAPK and Akt were measured during 72 hours after burn. RESULTS: Renal function as assessed by serum creatinine and blood urea nitrogen deteriorated significantly at 3 h after burn, alleviated at 6 h but worsened at 48 h and 72 h, indicating a late ARF was induced. Apoptotic cells and cleavage caspase-3 in the kidney went up slowly and turned into significant at 48 h and 72 h. Tubular cell ROS production shot up at 6 h and continuously rose during the 72-h experiment. Scavenging ROS with tempol markedly attenuated tubular apoptosis and renal dysfunction at 72 h after burn. Interestingly, renal p38 MAPK phosphorylation elevated in a time dependent manner whereas Akt phosphorylation increased during the first 24 h but decreased at 48 h after burn. The p38 MAPK specific inhibitor SB203580 alleviated whereas Akt inhibitor exacerbated burn-induced tubular apoptosis and renal dysfunction. Furthermore, tempol treatment exerted a duplex regulation through inhibiting p38 MAPK phosphorylation but further increasing Akt phosphorylation at 72 h postburn. CONCLUSIONS: These results demonstrate that sustained renal ROS overproduction induces continuous tubular cell apoptosis and thus a late ARF at 72 h after burn in severely burned rats, which may result from ROS-mediated activation of p38 MAPK but a late inhibition of Akt phosphorylation.

Protein- and diabetes-induced glomerular hyperfiltration: role of glucagon, vasopressin, and urea.

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Bankir, Lise; Roussel, Ronan; Bouby, Nadine

2015-07-01

A single protein-rich meal (or an infusion of amino acids) is known to increase the glomerular filtration rate (GFR) for a few hours, a phenomenon known as "hyperfiltration." It is important to understand the factors that initiate this upregulation because it becomes maladaptive in the long term. Several mediators and paracrine factors have been shown to participate in this upregulation, but they are not directly triggered by protein intake. Here, we explain how a rise in glucagon and in vasopressin secretion, directly induced by protein ingestion, might be the initial factors triggering the hepatic and renal events leading to an increase in the GFR. Their effects include metabolic actions in the liver and stimulation of sodium chloride reabsorption in the thick ascending limb. Glucagon is not only a glucoregulatory hormone. It is also important for the excretion of nitrogen end products by stimulating both urea synthesis in the liver (along with gluconeogenesis from amino acids) and urea excretion by the kidney. Vasopressin allows the concentration of nitrogenous end products (urea, ammonia, etc.) and other protein-associated wastes in a hyperosmotic urine, thus allowing a very significant water economy characteristic of all terrestrial mammals. No hyperfiltration occurs in the absence of one or the other hormone. Experimental results suggest that the combined actions of these two hormones, along with the complex intrarenal handling of urea, lead to alter the composition of the tubular fluid at the macula densa and to reduce the intensity of the signal activating the tubuloglomerular feedback control of GFR, thus allowing GFR to raise. Altogether, glucagon, vasopressin, and urea contribute to set up the best compromise between efficient urea excretion and water economy. Copyright © 2015 the American Physiological Society.

21 CFR 176.320 - Sodium nitrate-urea complex.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a component of articles intended for use in producing...

BUN (Blood Urea Nitrogen): MedlinePlus Lab Test Information

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... https://medlineplus.gov/labtests/bunbloodureanitrogen.html BUN (Blood Urea Nitrogen) To use the sharing features on this ... please enable JavaScript. What is a BUN (Blood Urea Nitrogen) Test? A BUN, or blood urea nitrogen ...

Urea-induced oxidative damage in Elodea densa leaves.

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Maleva, Maria; Borisova, Galina; Chukina, Nadezda; Prasad, M N V

2015-09-01

Urea being a fertilizer is expected to be less toxic to plants. However, it was found that urea at 100 mg L(-1) caused the oxidative stress in Elodea leaves due to the formation of reactive oxygen species (ROS) and lipid peroxidation that are known to stimulate antioxidant pathway. Urea at a concentration of 500 and 1000 mg L(-1) decreased low-molecular-weight antioxidants. In this case, the antioxidant status of plants was supported by the activity of antioxidant enzymes such as superoxide dismutase and guaiacol peroxidase. A significant increase in the soluble proteins and -SH groups was observed with high concentrations of urea (30-60 % of control). Thus, the increased activity of antioxidant enzymes, low-molecular-weight antioxidants, and induced soluble protein thiols are implicated in plant resistance to oxidative stress imposed by urea. We found that guaiacol peroxidase plays an important role in the removal of the peroxide in Elodea leaves exposed to 1000 mg L(-1)of urea.

The effect of CP concentration in the diet on urea kinetics and microbial usage of recycled urea in cattle: a meta-analysis.

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Batista, E D; Detmann, E; Valadares Filho, S C; Titgemeyer, E C; Valadares, R F D

2017-08-01

In ruminants, urea recycling is considered an evolutionary advantage. The amount of urea recycled mainly depends of the nitrogen (N) intake and the amount of organic matter (OM) digested in the rumen. Because recycled N contributes to meeting microbial N requirements, accurate estimates of urea recycling can improve the understanding of efficiency of N utilization and N losses to the environment. The objective of this study was to evaluate urea kinetics and microbial usage of recycled urea N in ruminants using a meta-analytical approach. Treatment mean values were compiled from 25 studies with ruminants (beef cattle, dairy cows and sheep) which were published from 2001 to 2016, totalling 107 treatment means. The data set was analyzed according to meta-analysis techniques using linear or non-linear mixed models, taking into account the random variations among experiments. Urea N synthesized in the liver (UER) and urea N recycled to the gut (GER) linearly increased (PCP concentration and the ratio of CP to digestible OM (CP:DOM). Maximum curvature analyses identified 17% dietary CP as the point where there was a prominent increase in hepatic synthesis of urea N, likely due to an excess of dietary N leading to greater ammonia absorption. The GER:UER decreased with increasing dietary CP concentration (PCP⩾19%, GER:UER reached near minimal values. The fraction of UER eliminated as urinary urea N and the contribution of urea N to total urinary N were positively associated with dietary CP (PCP was 17%. The fractions of GER excreted in the feces and utilized for anabolism decreased, whereas the fraction of GER returned to the ornithine cycle increased with dietary CP concentration (PCP and CP:DOM increased (PCP/kg DOM. The models obtained in this study contribute to the knowledge on N utilization, and they could be used in feeding models to predict urea recycling and thus to improve formulation of diets to reduce N losses that contribute to air and water pollution.

Effects of trimethylamine N-oxide and urea on DNA duplex and G-quadruplex.

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Ueda, Yu-Mi; Zouzumi, Yu-Ki; Maruyama, Atsushi; Nakano, Shu-Ichi; Sugimoto, Naoki; Miyoshi, Daisuke

2016-01-01

We systematically investigated effects of molecular crowding with trimethylamine N -oxide (TMAO) as a zwitterionic and protective osmolyte and urea as a nonionic denaturing osmolyte on conformation and thermodynamics of the canonical DNA duplex and the non-canonical DNA G-quadruplex. It was found that TMAO and urea stabilized and destabilized, respectively, the G-quadruplex. On the other hand, these osmolytes generally destabilize the duplex; however, it was observed that osmolytes having the trimethylamine group stabilized the duplex at the lower concentrations because of a direct binding to a groove of the duplex. These results are useful not only to predict DNA structures and their thermodynamics under physiological environments in living cells, but also design of polymers and materials to regulate structure and stability of DNA sequences.

Atorvastatin attenuates experimental contrast-induced acute kidney injury: a role for TLR4/MyD88 signaling pathway.

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Yue, Rongzheng; Zuo, Chuan; Zeng, Jing; Su, Baihai; Tao, Ye; Huang, Songmin; Zeng, Rui

2017-11-01

To investigate the protective effect of different atorvastatin doses on contrast-induced acute kidney injury and the related mechanism. Healthy male Sprague-Dawley (SD) rats were randomly divided into the blank control group, experimental control group and different-dose atorvastatin groups. A rat model of contrast-induced acute kidney injury was established. We detected changes in serum creatinine (Scr) and blood urea nitrogen (BUN) before and after model establishment, observed and scored renal tubular injury, analyzed rat renal cell apoptosis, and measure the expression of signal pathway proteins and downstream inflammatory factors. After contrast agent injection, the Scr and BUN levels of the experimental control group were significantly increased, the different doses applied in the atorvastatin group significantly reduced the Scr and BUN levels (p atorvastatin doses have protective effects on contrast-induced acute renal tubular injury in rats, possibly by targeting TLR4, suppressing TLR4 expression, regulating the TLR4/Myd88 signaling pathway, and inhibiting the expression of downstream inflammatory factors.

Systemic administration of a novel human umbilical cord mesenchymal stem cells population accelerates the resolution of acute liver injury

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Burra Patrizia

2012-07-01

Full Text Available Abstract Background Hepatocytes and stem cells transplantation may be an alternative to liver transplantation in acute or chronic liver disease. We aimed to evaluate the therapeutic potential of mesenchymal stem cells from human umbilical cord (UCMSCs, a readily available source of mesenchymal stem cells, in the CCl4-induced acute liver injury model. Methods Mesenchymal stem cells profile was analyzed by flow cytometry. In order to evaluate the capability of our UCMSCs to differentiate in hepatocytes, cells were seeded on three different supports, untreated plastic support, MatrigelTM and human liver acellular matrix. Cells were analyzed by immunocitochemistry for alpha-fetoprotein and albumin expression, qPCR for hepatocyte markers gene expression, Periodic Acid-Schiff staining for glycogen storage, ELISA for albumin detection and colorimetric assay for urea secretion. To assess the effects of undifferentiated UCMSCs in hepatic regeneration after an acute liver injury, we transplanted them via tail vein in mice injected intraperitoneally with a single dose of CCl4. Livers were analyzed by histological evaluation for damage quantification, immunostaining for Kupffer and stellate cells/liver myofibroblasts activation and for UCMSCs homing. Pro- and anti-inflammatory cytokines gene expression was evaluated by qPCR analysis and antioxidant enzyme activity was measured by catalase quantification. Data were analyzed by Mann–Whitney U-test, Kruskal-Wallis test and Cuzick’s test followed by Bonferroni correction for multiple comparisons. Results We have standardized the isolation procedure to obtain a cell population with hepatogenic properties prior to in vivo transplantation. When subjected to hepatogenic differentiation on untreated plastic support, UCMSCs differentiated in hepatocyte-like cells as demonstrated by their morphology, progressive up-regulation of mature hepatocyte markers, glycogen storage, albumin and urea secretion. However

Nutritional factors influencing milk urea in buffaloes

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V. Proto

2011-03-01

Full Text Available Urea is the primary form in which N is excreted in ruminants. Milk urea (MU content was introduced as a means to monitor the efficiency of protein utilisation in dairy cattle (Baker et al., 1995; Roseler et al., 1993; Bertoni, 1995. In this study the effect of some nutrition factors on MU content in buffalo herds was analysed in order to examine the possibility that protein nutrition could be monitored by means of milk urea at herd level........

comparative studies on the mineralization of furfural urea and urea

African Journals Online (AJOL)

DR. AMINU

2013-12-02

Dec 2, 2013 ... In this research, laboratory studies were conducted to evaluate the effects of furfural urea as a slow release N ... regarding groundwater pollution ( Myrold, 2008). The ... The plastic pots containing the treated soil sample and.

RESPON TANAMAN ROSELA BUNGA MERAH (Hibiscus sabdariffa L. TERHADAP APLIKASI FUNGI MIKORIZA ARBUSKULA DAN PUPUK UREA PADA TANAH JENIS GRUMOSOL (VERTISOLS

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Sinar Suryawati

2011-03-01

Full Text Available This research aims to study the effect of combined aplication Arbuscular Mycorrhiza (AM and Urea to the growth, productivity and quality of roselle plants (Hibiscus sabdariffa L.. The research was conducted at the experimental garden and the Laboratory of Agroecotechnology Department, Faculty of Agriculture, University of Trunojoyo. The study consist of six treatment combinations, repeated 3 times, and based on randomized block design. The observation parameters includes the growth, production and quality of leaf and flower. ANOVA showed that there is no significant effect of combination of AMF and urea on growth parameters, productivity and leaf quality observations, but the real impact on the quality of flowers. Aplication of urea up to 50 kg / ha is still giving the highest effect on growth, plant productivity, vitamine C and protein rosella flowers but decreased the content of vitamin C and protein of leaves. Aplication of AM up to 5 g / plant had the same pattern with the aplication of urea.

The effect of urea with urease inhibitors and urea on yield and nitrate content in potato tubers

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Karel Drápal

2013-01-01

Full Text Available The three-year field trial was established on two localities – Žabčice and Valečov in 2010–2012. Seven variants of nitrogen fertilization in four replications have been involved in this experiment – 100% of urea (U, 80% of urea, 60% of urea, 100% of UreaStabil (US, 80% of UreaStabil and 60% of UreaStabil, whilst 100% corresponded to 90 kg N.ha−1 after subtracting the content of Nmin in the soil, and the control variant without fertilization by mineral nitrogen. The two varieties with different lengths of vegetation periods have been chosen for the experiment – the early variety Karin and the mid-early variety Red Anna. In all cases, samples for the yield and qualitative analyses have been taken according to the phenological phase – the beginning of physiological maturity. The obtained results show that the highest average yield has been achieved in the variant of 100% of urea – 40.95 t. ha−1, the yield of this variant was statistically significantly higher than the yield of the other variants of fertilization (P < 0.05. Variants treated by urea without the urease inhibitor reached an average yield of 37.62 t.ha−1. However, this yield was not statistically significantly higher when comparing to the urea with the urease inhibitor (P > 0.05. In regard to localities, a relatively high average yield (44.58 t.ha−1 has been achieved on a characteristically potato-growing locality Valečov. This yield was statistically significantly higher than the one attained on the Žabčice locality (P < 0.05. In respect to varieties, the mid-early variety Red Anna attained a higher average yield (39.65 t. ha−1. Likewise, this yield was statistically significantly higher than the one of the early variety Karin (P < 0.05. The best year was 2012, in which the average yield of 38.73 t.ha−1 was achieved. This yield was statistically significantly higher than the yield of the year 2010 (P < 0.05. As far as nitrates are concerned, the

Entry of blood urea into the rumen of the llama

International Nuclear Information System (INIS)

Hinderer, S.; Engelhardt, W. von

1976-01-01

Transfer of body urea into the temporarily isolated rumen cleaned and filled with a test solution was measured in the llama. Simultaneously urea recirculation into the total gastro-intestinal tract (GI-tract) was estimated using 14 C-urea. The permeability of the rumen wall to urea could be changed significantly. With CO 2 or butyric acid in the test solution, permeability was highest, it was low when food was withheld and when no volatile fatty acids were present in the solution. Changes in the permeability can affect the transfer of blood urea across the rumen wall more extensively than changes in plasma urea concentrations. (author)

Effect of various practical warm-up protocols on acute lower-body power.

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Buttifant, David; Hrysomallis, Con

2015-03-01

The purpose of this study was to compare the acute effect of box squats with barbell (BBSquat), box squats with elastic resistance bands (BandSquat), and static stretches (SStretch) on external power during a 20-kg weighted jump squat. Twelve male athletes performed each of the 3 warm-up protocols on separate occasions in a randomized order. Weighted jump squat power was assessed using a linear position transducer attached to the bar of a Smith machine. Jump power was measured pre-warm-up and 5 and 10 minutes post-warm-up protocol. The BBSquat protocol involved 3 sets of 3RM, BandSquat involved 3 sets of 3 repetitions using highest resistance elastic bands, and the SStretch protocol comprises two 30-second stretches for muscles of the lower limbs. Jump power significantly increased from pre-warm-up to 5 and 10 minutes post-warm-up for both the BandSquat and BBSquat protocols. There was no statistical difference in power values between BandSquat and BBSquat. Power output significantly decreased from pre-warm-up to 5 and 10 minutes post-warm-up for the SStretch protocol. The BandSquat was just as effective as BBSquat in augmenting acute jump power. The SStretch was detrimental to jump performance. A practical warm-up using relatively inexpensive and portable equipment such as elastic resistance bands was just as effective as a warm-up protocol that requires more substantial and less transportable equipment such as a squat rack and associated free weights. The BandSquat warm-up may be considered more accessible for athletes at various competition levels.

Urea immunoliposome inhibits human vascular endothelial cell proliferation for hemangioma treatment

Science.gov (United States)

2013-01-01

Background Urea injection has been used in hemangioma treatment as sclerotherapy. It shrinks vascular endothelial cells and induces degeneration, necrosis, and fibrosis. However, this treatment still has disadvantages, such as lacking targeting and difficulty in controlling the urea dosage. Thus, we designed a urea immunoliposome to improve the efficiency of treatment. Methods The urea liposome was prepared by reverse phase evaporation. Furthermore, the urea immunoliposome was generated by coupling the urea liposome with a vascular endothelial growth factor receptor (VEGFR) monoclonal antibody using the glutaraldehyde cross-linking method. The influence of the urea immunoliposome on cultured human hemangioma vascular endothelial cells was observed preliminarily. Results Urea immunoliposomes showed typical liposome morphology under a transmission electron microscope, with an encapsulation percentage of 54.4% and a coupling rate of 36.84% for anti-VEGFR. Treatment with the urea immunoliposome significantly inhibited the proliferation of hemangioma vascular endothelial cells (HVECs) in a time- and dose-dependent manner. Conclusions The urea immunoliposome that we developed distinctly and persistently inhibited the proliferation of HVECs and is expected to be used in clinical hemangioma treatment. PMID:24266957

The crystal structure of urea nitrate

NARCIS (Netherlands)

Harkema, Sybolt; Feil, D.

1969-01-01

The structure of urea nitrate has been solved, by the use of three-dimensional X-ray data. Data were collected using Cu Ke and Mo K0~ radiations. The structure consists of layers with urea and nitrate groups held together by hydrogen bonds. The positions of all hydrogen atoms were found. The final R

Bottom-up and top-down emotion generation: implications for emotion regulation

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Misra, Supriya; Prasad, Aditya K.; Pereira, Sean C.; Gross, James J.

2012-01-01

Emotion regulation plays a crucial role in adaptive functioning and mounting evidence suggests that some emotion regulation strategies are often more effective than others. However, little attention has been paid to the different ways emotions can be generated: from the ‘bottom-up’ (in response to inherently emotional perceptual properties of the stimulus) or ‘top-down’ (in response to cognitive evaluations). Based on a process priming principle, we hypothesized that mode of emotion generation would interact with subsequent emotion regulation. Specifically, we predicted that top-down emotions would be more successfully regulated by a top-down regulation strategy than bottom-up emotions. To test this hypothesis, we induced bottom-up and top-down emotions, and asked participants to decrease the negative impact of these emotions using cognitive reappraisal. We observed the predicted interaction between generation and regulation in two measures of emotional responding. As measured by self-reported affect, cognitive reappraisal was more successful on top-down generated emotions than bottom-up generated emotions. Neurally, reappraisal of bottom-up generated emotions resulted in a paradoxical increase of amygdala activity. This interaction between mode of emotion generation and subsequent regulation should be taken into account when comparing of the efficacy of different types of emotion regulation, as well as when reappraisal is used to treat different types of clinical disorders. PMID:21296865

Urea thermolysis and NOx reduction with and without SCR catalysts

International Nuclear Information System (INIS)

Fang, Howard L.; DaCosta, Herbert F.M.

2003-01-01

Urea-selective catalytic reduction (SCR) has been a leading contender for removal of nitrogen oxides (deNO x ) from diesel engine emissions. Despite its advantages, the SCR technology faces some critical detriments to its catalytic performance such as catalyst surface passivation (caused by deposit formation) and consequent stoichiometric imbalance of the urea consumption. Deposit formation deactivates catalytic performance by not only consuming part of the ammonia produced during urea decomposition but also degrading the structural and thermal properties of the catalyst surface. We have characterized the urea thermolysis with and without the urea-SCR catalyst using both spectroscopic (DRIFTS and Raman) and thermal techniques (thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC)) to identify the deposit components and their corresponding thermal properties. Urea thermolysis exhibits two decomposition stages, involving ammonia generation and consumption, respectively. The decomposition after the second stage leads to the product of melamine complexes, (HNC=NH) x (HNCO) y , that hinder catalytic performance. The presence of catalyst accompanied with a good spray of the urea solution helps to eliminate the second stage. In this work, kinetics of the direct reduction of NO x by urea is determined and the possibility of using additives to the urea solution in order to rejuvenate the catalyst surface and improve its performance will be discussed

Pengolahan Limbah Cair Pabrik Pupuk Urea Menggunakan Advanced Oxidation Processes

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Darmadi Darmadi

2014-06-01

Full Text Available Limbah cair pabrik pupuk urea terdiri dari urea dan amonium yang masing-masing mempunyai konsentrasi berkisar antara 1500-10000 ppm dan 400-3000 ppm. Konsentrasi urea yang tinggi di dalam badan air dapat menyebabkan blooming algae dalam ekosistem tersebut yang dapat mengakibatkan kehidupan biota air lain terserang penyakit. Peristiwa ini terjadi karena kurangnya nutrisi bagi biota air dan sedikitnya sinar matahari yang dapat menembusi permukaan air. Disamping kedua hal tersebut di atas, algae juga dapat memproduksi senyawa beracun bagi biota air dan manusia. Penelitian ini bertujuan untuk mengolah urea menggunakan oksidasi konvensional (H2O2 dan Advanced Oxidation Processes (kombinasi H2O2-Fe2+ pada pH 5 dengan parameter yang digunakan adalah variasi konsen-trasi awal H2O2  dan konsentrasi Fe2+. Hasil percobaan menunjukkan bahwa penurunan konsentrasi urea tertinggi diperoleh pada penggunaan reagen fenton (8000 ppm H2O2 dan 500 ppm Fe2+, yaitu dapat menurunkan urea dari konsentrasi awal urea 2566,145 ppm menjadi 0 ppm. Kinetika reaksi dekomposisi urea menjadi amonium dan amonium menjadi nitrit dan nitrat yang diuji mengikuti laju kinetika reaksi orde 1 (satu terhadap urea dan orde satu terhadap amonium dengan konstanta laju reaksi masing-masing k1 = 0,019 dan k2 = 0,022 min-1.

Alanine Counteracts the Destabilizing Effect that Urea has on RNase-A.

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Chowhan, Rimpy K; Ali, Fasil; Bhat, Mohd Y; Rahman, Safikur; Singh, Laishram R; Ahmad, Faizan; Dar, Tanveer A

2016-01-01

It is generally believed that organisms use and accumulate methylamine osmolytes to prevent urea's damaging effect on protein stability and activity. However, urea-rich cells not only accumulate methylamines but also many other methylated and non-methylated compounds as well. But, so far it is not known whether osmolytes that are not accumulated in urea-rich cells could also confer urea-counteracting properties. We investigated the behavior of a non-methylamine osmolyte, alanine for its counteracting effect against urea denaturation of a model protein, ribonuclease A (RNase-A). We have measured structure and thermodynamic parameters (Tm, ΔHm, and ΔGD°) of RNase-A in the presence of alanine, urea and their combination. The results were also compared with the ability of glycine (osmolyte lacking one methyl group when compared with alanine) to counter urea's effect on protein stability. We observed that alanine but not glycine counteracts urea's harmful effect on RNase-A stability. The results indicated that alanine (in addition to methylamine osmolytes) may serve as an alternate urea-counteractant. Since glycine fails to protect RNase-A from urea's destabilizing effect, it seems that methylation to glycine might have some evolutionary significance to protect proteins against harmful effects of urea.

Mechanisms of Hypoxic Up-Regulation of Versican Gene Expression in Macrophages.

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Fattah Sotoodehnejadnematalahi

Full Text Available Hypoxia is a hallmark of many pathological tissues. Macrophages accumulate in hypoxic sites and up-regulate a range of hypoxia-inducible genes. The matrix proteoglycan versican has been identified as one such gene, but the mechanisms responsible for hypoxic induction are not fully characterised. Here we investigate the up-regulation of versican by hypoxia in primary human monocyte-derived macrophages (HMDM, and, intriguingly, show that versican mRNA is up-regulated much more highly (>600 fold by long term hypoxia (5 days than by 1 day of hypoxia (48 fold. We report that versican mRNA decay rates are not affected by hypoxia, demonstrating that hypoxic induction of versican mRNA is mediated by increased transcription. Deletion analysis of the promoter identified two regions required for high level promoter activity of luciferase reporter constructs in human macrophages. The hypoxia-inducible transcription factor HIF-1 has previously been implicated as a key potential regulator of versican expression in hypoxia, however our data suggest that HIF-1 up-regulation is unlikely to be principally responsible for the high levels of induction observed in HMDM. Treatment of HMDM with two distinct specific inhibitors of Phosphoinositide 3-kinase (PI3K, LY290042 and wortmannin, significantly reduced induction of versican mRNA by hypoxia and provides evidence of a role for PI3K in hypoxic up-regulation of versican expression.

76 FR 15339 - Solid Urea From Russia and Ukraine

Science.gov (United States)

2011-03-21

... Urea From Russia and Ukraine AGENCY: United States International Trade Commission. ACTION: Notice of... urea from Russia and Ukraine. SUMMARY: The Commission hereby gives notice that it will proceed with... determine whether revocation of the antidumping duty orders on solid urea from Russia and Ukraine would be...

Experimental studies on urea degradation in seawater

Digital Repository Service at National Institute of Oceanography (India)

Rajendran, A.; Joseph, T.; Reddy, C.V.G.

polluted waters, resulting in the accumulation of ammonia. The urea decomposing bacteria varied between 7 and 40% among the total heterotrophic bacteria in Velsao Bay, while these were from 15 to 22% near Mormugao. The rate for biological oxidation of urea...

Biodegradable Mulches Based on Poly(vinyl Alcohol, Kenaf Fiber, and Urea

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Boon Khoon Tan

2015-07-01

Full Text Available This paper describes the preparation of poly(vinyl alcohol/kenaf fiber (PVOH/KF composites with entrapped urea. The major FTIR peaks of these composites could be identified. These composites are intended for agricultural applications as biodegradable mulches and could be potential carrier materials for fertilizer. The water solubility, release behavior, chemical properties, and thermal stability of the composites were evaluated. The composites lost 25% of their weight after 7 days in water. In a wet environment, urea was released from the composites through its dissolution in water, and around 57% of the urea was released from the composites in 24 h; Thermagravimetric analysis showed that these composites were stable up 150 C. These composites would be able to withstand rain and protect seedlings from the sun when applied in the field as mulches. For around three to four weeks, these biobased mulches could slowly disintegrate as the PVOH binder was gradually dissolved by moisture, releasing the kenaf fibers to serve as soil fertilizer without leaving any undegradable waste for disposal. Hence, they would not pose any risks to the land or biological systems.

Guidance Cue Netrin-1 and the Regulation of Inflammation in Acute and Chronic Kidney Disease

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Punithavathi Ranganathan

2014-01-01

Full Text Available Acute kidney injury (AKI is a common problem in the hospital setting and intensive care unit. Despite improved understanding, there are no effective therapies available to treat AKI. A large body of evidence strongly suggests that ischemia reperfusion injury is an inflammatory disease mediated by both adaptive and innate immune systems. Cell migration also plays an important role in embryonic development and inflammation, and this process is highly regulated to ensure tissue homeostasis. One such paradigm exists in the developing nervous system, where neuronal migration is mediated by a balance between chemoattractive and chemorepulsive signals. The ability of the guidance molecule netrin-1 to repulse or abolish attraction of neuronal cells expressing the UNC5B receptor makes it an attractive candidate for the regulation of inflammatory cell migration. Recent identification of netrin-1 as regulators of immune cell migration has led to a large number of studies looking into how netrin-1 controls inflammation and inflammatory cell migration. This review will focus on recent advances in understanding netrin-1 mediated regulation of inflammation during acute and chronic kidney disease and whether netrin-1 and its receptor activation can be used to treat acute and chronic kidney disease.

A Urea Potentiometric Biosensor Based on a Thiophene Copolymer

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Cheng-Yuan (Kevin Lai

2017-03-01

Full Text Available A potentiometric enzyme biosensor is a convenient detector for quantification of urea concentrations in industrial processes, or for monitoring patients with diabetes, kidney damage or liver malfunction. In this work, poly(3-hexylthiophene-co-3-thiopheneacetic acid (P(3HT-co-3TAA was chemically synthesized, characterized and spin-coated onto conductive indium tin oxide (ITO glass electrodes. Urease (Urs was covalently attached to the smooth surface of this copolymer via carbodiimide coupling. The electrochemical behavior and stability of the modified Urs/P(3HT-co-3TAA/ITO glass electrode were investigated by cyclic voltammetry, and the bound enzyme activity was confirmed by spectrophotometry. Potentiometric response studies indicated that this electrode could determine the concentration of urea in aqueous solutions, with a quasi-Nernstian response up to about 5 mM. No attempt was made to optimize the response speed; full equilibration occurred after 10 min, but the half-time for response was typically <1 min.

Development of melamine modified urea formaldehyde resins based o nstrong acidic pH catalyzed urea formaldehyde polymer

Science.gov (United States)

Chung-Yun Hse

2009-01-01

To upgrade the performance of urea-formaldehyde (UF) resin bonded particleboards, melamine modified urea-formaldehyde (MUF) resins based on strong acidic pH catalyzed UF polymers were investigated. The study was conducted in a series of two experiments: 1) formulation of MUF resins based on a UF polymer catalyzed with strong acidic pH and 2) determination of the...

Analysis Ratio of Uranyl/Urea and Uranyl/HMTA on the ComplexesUranyl-Urea and Uranyl-HMTA with Spectrophotometry Method

International Nuclear Information System (INIS)

Simbolon, Sahat

2000-01-01

Reaction between uranyl and urea and uranyl and HMTA was investigated atpH = 4 and room temperature. The result of the reaction was measured withspectrophotometer, each absorbance was pictured between mol fraction andabsorbance for uranyl - urea and uranyl - HMTA. The linear and horizontalcurve was found for reaction uranyl - urea, meanwhile S curve for thereaction uranyl and HMTA. It was found that reaction between uranyl and HMTAon mol fraction value less than 0.25 was complexes meanwhile on the range of0.25 and 0.5 the reaction between uranyl and HMTA was stoichiometries.(author)

Testing the ability of non-methylamine osmolytes present in kidney cells to counteract the deleterious effects of urea on structure, stability and function of proteins.

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Sheeza Khan

Full Text Available Human kidney cells are under constant urea stress due to its urine concentrating mechanism. It is believed that the deleterious effect of urea is counteracted by methylamine osmolytes (glycine betaine and glycerophosphocholine present in kidney cells. A question arises: Do the stabilizing osmolytes, non-methylamines (myo-inositol, sorbitol and taurine present in the kidney cells also counteract the deleterious effects of urea? To answer this question, we have measured structure, thermodynamic stability (ΔG D (o and functional activity parameters (K m and k cat of different model proteins in the presence of various concentrations of urea and each non-methylamine osmolyte alone and in combination. We observed that (i for each protein myo-inositol provides perfect counteraction at 1∶2 ([myo-inositol]:[urea] ratio, (ii any concentration of sorbitol fails to refold urea denatured proteins if it is six times less than that of urea, and (iii taurine regulates perfect counteraction in a protein specific manner; 1.5∶2.0, 1.2∶2.0 and 1.0∶2.0 ([taurine]:[urea] ratios for RNase-A, lysozyme and α-lactalbumin, respectively.

A fuzzy logic urea dosage controller design for two-cell selective catalytic reduction systems.

Science.gov (United States)

You, Kun; Wei, Lijiang; Jiang, Kai

2017-12-22

Diesel engines have dominated in the heavy-duty vehicular and marine power source. However, the induced air pollution is a big problem. As people's awareness of environmental protection increasing, the emission regulations of diesel-engine are becoming more stringent. In order to achieve the emission regulations, the after-treatment system is a necessary choice. Specifically, the selective catalytic reduction (SCR) system has been widely applied to reduce the NO X emissions of diesel engine. Different from single-cell SCR systems, the two-cell systems have various benefits from the modeling and control perspective. In this paper, the urea dosage controller design for two-cell SCR systems was investigated. Firstly, the two-cell SCR modeling was introduced. Based on the developed model, the design procedure for the fuzzy logic urea dosage controller was well addressed. Secondly, simulations and comparisons were employed via an experimental verification of the whole vehicle simulator. And the results showed that the designed controller simultaneously achieved high NO X reduction rate and low tail-pipe ammonia slip. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Cytokinins and urea derivatives stimulate seed germination in Lotus corniculatus L.

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Nikolić Radomirka

2007-01-01

Full Text Available We studied the effects of various cytokinins and urea derivatives on germination of aged seeds of in Lotus corniculatus L. The following substances were applied: N6-isoprenoid cytokinins (isopentenyl adenine and zeatin, adenine sulfate, N6-aromatic cytokinins (kinetin, benzyladenine and their N9-ribosides, N-benzyl-9-(2- tetrahydropyranyladenine, and urea derivatives (diphenylurea, thidiazuron, and chloro-pyridyl phenylurea. With the exception of adenine sulfate, all cytokinins increased the percentage of seed germination up to twofold, depending on their kind and concentration. It is concluded that cytokinins may be among the missing factors in aged seeds of L. corniculatus contributing to the implementation of their full germination potential. They could be used to improve germination of both freshly harvested and aged seed samples, if necessary. .

Assessment of Health Effects of Exogenous Urea: Summary and Key Findings.

Science.gov (United States)

Dickerson, Aisha S; Lee, Janice S; Keshava, Channa; Hotchkiss, Andrew; Persad, Amanda S

2018-05-01

Urea has been utilized as a reductant in diesel fuels to lower emission of nitrogen oxides, igniting interest in probable human health hazards associated with exposure to exogenous urea. Here, we summarize and update key findings on potential health effects of exogenous urea, including carcinogenicity. No definitive target organs for oral exposure were identified; however, results in animal studies suggest that the liver and kidney could be potential target organs of urea toxicity. The available human-subject literature suggests that the impact on lung function is minimal. Based on the literature on exogenous urea, we concluded that there was inadequate information to assess the carcinogenic potential of urea, or perform a quantitative assessment to derive reference values. Given the limited information on exogenous urea, additional research to address gaps for exogenous urea should include long-term cancer bioassays, two-generation reproductive toxicity studies, and mode-of-action investigations.

Diminished renal urea excretion in the llama at reduced food intake

International Nuclear Information System (INIS)

Engelhardt, W.; Engelhardt, W. von

1976-01-01

Renal urea excretion was studied in three llamas under various feeding conditions. Glomerular filtration rate (GFR) was estimated from inulin clearance. Tubular reabsorbed urea was the difference between glomerular filtered and renal excreted urea. Plasma urea concentration increased significantly when feeding was reduced by 40% and 60%, not applicable to a straw diet. With reduced hay feeding and on a straw diet only a slight and insignificant decrease was observed in renal urea excretion, with only a 3% lowering in GFR and glomerular filtered urea. With a straw diet, the glomerular filtered urea was significantly below the controls. The fraction of filtered urea reabsorbed in the tubules was constant (36%-47%). Very high reabsorption (87%) on a supplemented straw dietwas observed in one llama which after nearly 6 months on this low protein diet - could be shown to have lost only 5% of its body weight

Transgenic Restoration of Urea Transporter A1 Confers Maximal Urinary Concentration in the Absence of Urea Transporter A3.

Science.gov (United States)

Klein, Janet D; Wang, Yanhua; Mistry, Abinash; LaRocque, Lauren M; Molina, Patrick A; Rogers, Richard T; Blount, Mitsi A; Sands, Jeff M

2016-05-01

Urea has a critical role in urinary concentration. Mice lacking the inner medullary collecting duct (IMCD) urea transporter A1 (UT-A1) and urea transporter A3 (UT-A3) have very low levels of urea permeability and are unable to concentrate urine. To investigate the role of UT-A1 in the concentration of urine, we transgenically expressed UT-A1 in knockout mice lacking UT-A1 and UT-A3 using a construct with a UT-A1 gene that cannot be spliced to produce UT-A3. This construct was inserted behind the original UT-A promoter to yield a mouse expressing only UT-A1 (UT-A1(+/+)/UT-A3(-/-)). Western blot analysis demonstrated UT-A1 in the inner medulla of UT-A1(+/+)/UT-A3(-/-) and wild-type mice, but not in UT-A1/UT-A3 knockout mice, and an absence of UT-A3 in UT-A1(+/+)/UT-A3(-/-) and UT-A1/UT-A3 knockout mice. Immunohistochemistry in UT-A1(+/+)/UT-A3(-/-) mice also showed negative UT-A3 staining in kidney and other tissues and positive UT-A1 staining only in the IMCD. Urea permeability in isolated perfused IMCDs showed basal permeability in the UT-A1(+/+)/UT-A3(-/-) mice was similar to levels in wild-type mice, but vasopressin stimulation of urea permeability in wild-type mice was significantly greater (100% increase) than in UT-A1(+/+)/UT-A3(-/-) mice (8% increase). Notably, basal urine osmolalities in both wild-type and UT-A1(+/+)/UT-A3(-/-) mice increased upon overnight water restriction. We conclude that transgenic expression of UT-A1 restores basal urea permeability to the level in wild-type mice but does not restore vasopressin-stimulated levels of urea permeability. This information suggests that transgenic expression of UT-A1 alone in mice lacking UT-A1 and UT-A3 is sufficient to restore urine-concentrating ability. Copyright © 2016 by the American Society of Nephrology.

Influence of milk urea concentration on fractional urea disappearance rate from milk to blood plasma in dairy cows

NARCIS (Netherlands)

Spek, J.W.; Dijkstra, J.; Bannink, A.

2016-01-01

The relationship between milk urea nitrogen (MUN; mg of N/dL) and urinary N excretion is affected, among others, by diurnal dynamics in MUN, which in turn is largely influenced by feed intake pattern and characteristics of urea transfer from blood plasma to milk and vice versa. This study aimed

Urea-temperature phase diagrams capture the thermodynamics of denatured state expansion that accompany protein unfolding

Science.gov (United States)

Tischer, Alexander; Auton, Matthew

2013-01-01

We have analyzed the thermodynamic properties of the von Willebrand factor (VWF) A3 domain using urea-induced unfolding at variable temperature and thermal unfolding at variable urea concentrations to generate a phase diagram that quantitatively describes the equilibrium between native and denatured states. From this analysis, we were able to determine consistent thermodynamic parameters with various spectroscopic and calorimetric methods that define the urea–temperature parameter plane from cold denaturation to heat denaturation. Urea and thermal denaturation are experimentally reversible and independent of the thermal scan rate indicating that all transitions are at equilibrium and the van't Hoff and calorimetric enthalpies obtained from analysis of individual thermal transitions are equivalent demonstrating two-state character. Global analysis of the urea–temperature phase diagram results in a significantly higher enthalpy of unfolding than obtained from analysis of individual thermal transitions and significant cross correlations describing the urea dependence of and that define a complex temperature dependence of the m-value. Circular dichroism (CD) spectroscopy illustrates a large increase in secondary structure content of the urea-denatured state as temperature increases and a loss of secondary structure in the thermally denatured state upon addition of urea. These structural changes in the denatured ensemble make up ∼40% of the total ellipticity change indicating a highly compact thermally denatured state. The difference between the thermodynamic parameters obtained from phase diagram analysis and those obtained from analysis of individual thermal transitions illustrates that phase diagrams capture both contributions to unfolding and denatured state expansion and by comparison are able to decipher these contributions. PMID:23813497

Study on Urea Breath Test (UBT) a tool for helicobacter pylori infection

International Nuclear Information System (INIS)

Kolekar, R.V.; Bhade, S.P.D.; Reddy, Priyanka; Singh, Rajvir; Gadgil, Anita; Bhandarkar, Prashant; Roy, N.; Patil, S.P.

2016-01-01

Helicobacter pylori commonly called as H. pylori resides in the gastric epithelial mucosa and induces an inflammatory response leading to gastritis, peptic nicer disease and gastric malignancies. Detection and eradication of H.pylori infection is thus an important measure to prevent these. H.pylori has a worldwide prevalence rate of about 50%, with a higher prevalence in developing countries. Urea breath test, an outpatient noninvasive technique achieves up to 95% sensitivity and specificity at half the cost compared to histology, in detecting H. Pylori infection. Indian studies on the use of UBT and its standard protocol are sparse. The present paper discusses the application of Carbon-14 Urea breath test for the diagnosis of H pylori bacterial infection in 261 adult patients

Acute toxicity study of methanolic extract of Asparagus pubescens ...

African Journals Online (AJOL)

The acute toxicity study of methanolic extract of Asparagus pubescens root was studied on rats. The indices of the study were the liver enzymes (transaminases), cholesterol, creatinine and urea serum levels as well as the ionic analysis. Both alanine aminotransferase (ALT) and. Aspartate aminotransferase (AST) showed a ...

Solid state synthesis, crystal growth and optical properties of urea and p-chloronitrobenzene solid solution

Energy Technology Data Exchange (ETDEWEB)

Rai, R.N., E-mail: rn_rai@yahoo.co.in [Department of Chemistry, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005 (India); Kant, Shiva; Reddi, R.S.B. [Department of Chemistry, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005 (India); Ganesamoorthy, S. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamilnadu (India); Gupta, P.K. [Laser Materials Development & Devices Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

2016-01-15

Urea is an attractive material for frequency conversion of high power lasers to UV (for wavelength down to 190 nm), but its usage is hindered due to its hygroscopic nature, though there is no alternative organic NLO crystal which could be transparent up to 190 nm. The hygroscopic character of urea has been modified by making the solid solution (UCNB) of urea (U) and p-chloronitrobenzene (CNB). The formation of the solid solution of CNB in U is explained on the basis of phase diagram, powder XRD, FTIR, elemental analysis and single crystal XRD studies. The solubility of U, CNB and UCNB in ethanol solution is evaluated at different temperatures. Transparent single crystals of UCNB are grown from its saturated solution in ethanol. Optical properties e.g., second harmonic generation (SHG), refractive index and the band gap for UCNB crystal were measured and their values were compared with the parent compounds. Besides modification in hygroscopic nature, UCNB has also shown the higher SHG signal and mechanical hardness in comparison to urea crystal. - Highlights: • The hygroscopic character of urea was modified by making the solid solution • Solid solution formation is support by elemental, powder- and single crystal XRD • Crystal of solid solution has higher SHG signal and mechanical stability. • Refractive index and band gap of solid solution crystal have determined.

The effect of supplementing untreated, urea-supplemented and urea ...

African Journals Online (AJOL)

3x2x2 factorial experiment, involving an intake and in vivo digestibility trial with 48 adult S.A. Mutton Merino wethers. Straw dry matter (OM) intake on ammoniated wheat-straw diets was 27 and 22% higher (P ';;0,01) than on untreated and urea-supplemented diets, respectively. No significant difference was found between ...

Regulation of S1P receptors and sphingosine kinases expression in acute pulmonary endothelial cell injury

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Huiying Liu

2016-12-01

Full Text Available Background Acute lung injury and acute respiratory distress syndrome (ALI/ARDS is a severe clinical syndrome with mortality rate as high as 30–40%. There is no treatment yet to improve pulmonary endothelial barrier function in patients with severe pulmonary edema. Developing therapies to protect endothelial barrier integrity and stabilizing gas exchange is getting more and more attention. Sphingosine-1-phosphate (S1P is able to enhance the resistance of endothelial cell barrier. S1P at physiological concentrations plays an important role in maintaining endothelial barrier function. Proliferation, regeneration and anti-inflammatory activity that mesenchymal stem cells (MSCs exhibit make it possible to regulate the homeostatic control of S1P. Methods By building a pulmonary endothelial cell model of acute injury, we investigated the regulation of S1P receptors and sphingosine kinases expression by MSCs during the treatment of acute lung injury using RT-PCR, and investigated the HPAECs Micro-electronics impedance using Real Time Cellular Analysis. Results It was found that the down-regulation of TNF-α expression was more significant when MSC was used in combination with S1P. The combination effection mainly worked on S1PR2, S1PR3 and SphK2. The results show that when MSCs were used in combination with S1P, the selectivity of S1P receptors was increased and the homeostatic control of S1P concentration was improved through regulation of expression of S1P metabolic enzymes. Discussions The study found that, as a potential treatment, MSCs could work on multiple S1P related genes simultaneously. When it was used in combination with S1P, the expression regulation result of related genes was not simply the superposition of each other, but more significant outcome was obtained. This study establishes the experimental basis for further exploring the efficacy of improving endothelial barrier function in acute lung injury, using MSCs in combination with S1

Regulation of S1P receptors and sphingosine kinases expression in acute pulmonary endothelial cell injury.

Science.gov (United States)

Liu, Huiying; Zhang, Zili; Li, Puyuan; Yuan, Xin; Zheng, Jing; Liu, Jinwen; Bai, Changqing; Niu, Wenkai

2016-01-01

Acute lung injury and acute respiratory distress syndrome (ALI/ARDS) is a severe clinical syndrome with mortality rate as high as 30-40%. There is no treatment yet to improve pulmonary endothelial barrier function in patients with severe pulmonary edema. Developing therapies to protect endothelial barrier integrity and stabilizing gas exchange is getting more and more attention. Sphingosine-1-phosphate (S1P) is able to enhance the resistance of endothelial cell barrier. S1P at physiological concentrations plays an important role in maintaining endothelial barrier function. Proliferation, regeneration and anti-inflammatory activity that mesenchymal stem cells (MSCs) exhibit make it possible to regulate the homeostatic control of S1P. By building a pulmonary endothelial cell model of acute injury, we investigated the regulation of S1P receptors and sphingosine kinases expression by MSCs during the treatment of acute lung injury using RT-PCR, and investigated the HPAECs Micro-electronics impedance using Real Time Cellular Analysis. It was found that the down-regulation of TNF- α expression was more significant when MSC was used in combination with S1P. The combination effection mainly worked on S1PR2, S1PR3 and SphK2. The results show that when MSCs were used in combination with S1P, the selectivity of S1P receptors was increased and the homeostatic control of S1P concentration was improved through regulation of expression of S1P metabolic enzymes. The study found that, as a potential treatment, MSCs could work on multiple S1P related genes simultaneously. When it was used in combination with S1P, the expression regulation result of related genes was not simply the superposition of each other, but more significant outcome was obtained. This study establishes the experimental basis for further exploring the efficacy of improving endothelial barrier function in acute lung injury, using MSCs in combination with S1P and their possible synergistic mechanism.

Application of urea-15N in common bean (Phaseolus vulgaris, L.) CV. carioca

International Nuclear Information System (INIS)

Neptune, A.M.L.; Muraoka, T.

1978-01-01

A study was made in a Textural B Terra Roxa soil of medium fertility, by the use of different levels of Urea 15 N at seeding and at different stages of growth of common beans. Observations were made on the quantity of nitrogen uptaken by the crop, the efficiency of the plant in the utilization of the nitrogen fertilizer and yield. The application of urea, up to 120 kg N/ha, did not show a marked effect on yield, but the utilization of fertilizer nitrogen increased with the increase in nitrogen fertilizer levels. The up take of nitrogen by the bean crop was more efficient when the nitrogen fertilizer was applied before or at flowering stage rather than at seeding. The efficiency of nitrogen fertilizer utilization varied from 11.24% to 35.70%. There was no effect of inoculation on weight and number of nodules, with the rate of 120 kg N/ha [pt

Histones Induce the Procoagulant Phenotype of Endothelial Cells through Tissue Factor Up-Regulation and Thrombomodulin Down-Regulation.

Science.gov (United States)

Kim, Ji Eun; Yoo, Hyun Ju; Gu, Ja Yoon; Kim, Hyun Kyung

2016-01-01

The high circulating levels of histones found in various thrombotic diseases may compromise the anticoagulant barrier of endothelial cells. We determined how histones affect endothelial procoagulant tissue factor (TF) and anticoagulant thrombomodulin (TM). Surface antigens, soluble forms, and mRNA levels of TF and TM were measured by flow cytometry, ELISA, and real-time RT-PCR, respectively. TF and TM activity were measured using procoagulant activity, thrombin generation, or chromogenic assays. Involvement of the toll-like receptor (TLR) was assessed using the neutralizing antibodies. Histones dose-dependently induced surface antigens, activity and mRNA levels of endothelial TF. Histone-treated endothelial cells significantly shortened the lag time and enhanced the endogenous thrombin potential of normal plasma, which was normalized by a TF neutralizing antibody. Histones induced phosphatidylserine and protein-disulfide isomerase expression in endothelial cells. Histones also reduced the surface antigen, activity, and mRNA levels of endothelial TM. Polysialic acid and heparin reversed the histone-induced TF up-regulation and TM down-regulation. Activated protein C did not affect the TF up-regulation, but interrupted TM down-regulation. TLR2, and TLR4 inhibitors partially blocked the TF up-regulation. Histones induced the endothelial procoagulant phenotype through TF up-regulation and TM down-regulation. The effects of histones were partly mediated by TLR2, TLR4. Strategies to inhibit the harmful effects of histones in endothelial cells may be required in order to prevent a thrombotic environment.

Nitrogen utilization and transformation in red soil fertilized with urea and ryegrass

International Nuclear Information System (INIS)

Wu Gang; Zhang Qinzheng; Ye Qingfu; Zhu Zhujun; Xi Haifu; He Zhenli

1998-01-01

The influence of fertilization with urea and ryegrass on nitrogen utilization and transformation in red soil has been studied by using 15 N tracer method. When urea and ryegrass were applied alone or in combination, the percentage of N uptaken by ryegrass for labelled urea was 3 and 1.7 times that from labelled ryegrass for the application rate of 200 mgN·kg -1 and 100 mgN·kg -1 , respectively; combining application of ryegrass and urea reduced uptake of urea N and increased uptake of ryegrass N by ryegrass plant, but the percentage of N residue in soil increased for urea and decreased for ryegrass; when urea and ryegrass were applied alone, the percentage of N residue in soil from labelled ryegrass was more than 69% while that from labelled urea was less than 25%, and much more ryegrass N was incorporated into humus than urea N

Identification of anti-virulence compounds that disrupt quorum-sensing regulated acute and persistent pathogenicity.

Directory of Open Access Journals (Sweden)

Melissa Starkey

2014-08-01

Full Text Available Etiological agents of acute, persistent, or relapsing clinical infections are often refractory to antibiotics due to multidrug resistance and/or antibiotic tolerance. Pseudomonas aeruginosa is an opportunistic Gram-negative bacterial pathogen that causes recalcitrant and severe acute chronic and persistent human infections. Here, we target the MvfR-regulated P. aeruginosa quorum sensing (QS virulence pathway to isolate robust molecules that specifically inhibit infection without affecting bacterial growth or viability to mitigate selective resistance. Using a whole-cell high-throughput screen (HTS and structure-activity relationship (SAR analysis, we identify compounds that block the synthesis of both pro-persistence and pro-acute MvfR-dependent signaling molecules. These compounds, which share a benzamide-benzimidazole backbone and are unrelated to previous MvfR-regulon inhibitors, bind the global virulence QS transcriptional regulator, MvfR (PqsR; inhibit the MvfR regulon in multi-drug resistant isolates; are active against P. aeruginosa acute and persistent murine infections; and do not perturb bacterial growth. In addition, they are the first compounds identified to reduce the formation of antibiotic-tolerant persister cells. As such, these molecules provide for the development of next-generation clinical therapeutics to more effectively treat refractory and deleterious bacterial-human infections.

RUNX1 regulates phosphoinositide 3-kinase/AKT pathway: role in chemotherapy sensitivity in acute megakaryocytic leukemia.

Science.gov (United States)

Edwards, Holly; Xie, Chengzhi; LaFiura, Katherine M; Dombkowski, Alan A; Buck, Steven A; Boerner, Julie L; Taub, Jeffrey W; Matherly, Larry H; Ge, Yubin

2009-09-24

RUNX1 (AML1) encodes the core binding factor alpha subunit of a heterodimeric transcription factor complex which plays critical roles in normal hematopoiesis. Translocations or down-regulation of RUNX1 have been linked to favorable clinical outcomes in acute leukemias, suggesting that RUNX1 may also play critical roles in chemotherapy responses in acute leukemias; however, the molecular mechanisms remain unclear. The median level of RUNX1b transcripts in Down syndrome (DS) children with acute megakaryocytic leukemia (AMkL) were 4.4-fold (P regulation of PIK3CD by RUNX1 was further confirmed by chromatin immunoprecipitation and promoter reporter gene assays. Further, a PI3-kinase inhibitor, LY294002, and cytosine arabinoside synergized in antileukemia effects on Meg-01 and primary pediatric AMkL cells. Our results suggest that RUNX1 may play a critical role in chemotherapy response in AMkL by regulating the PI3-kinase/Akt pathway. Thus, the treatment of AMkL may be improved by integrating PI3-kinase or Akt inhibitors into the chemotherapy of this disease.

Reference Ranges of Serum Blood Urea Nitrogen, Creatinine Concentration and Ultrasonographic Measurement of the Kidneys in Term Healthy Newborns in the Neonatal Period

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Şebnem Kader

2017-12-01

Full Text Available Objective: Acute kidney injury is an important problem in neonates. We conducted a cross-sectional prospective study to determine normal serum blood urea nitrogen, creatinine reference ranges and ranges of ultrasonographic measurement of kidneys in healthy term newborns. Study Design: Blood samples were collected from total 357 healthy newborns at birth (n=45, 1st (n=30, 3rd (n=61, 7th (n=34, 10th (n=132, 14th (n=36, and 28th (n=19 days of life. Renal ultrasonographic was performed by the same two radiologists on 81 newborns aged 10 days. Results: Serum blood urea nitrogen and creatinine concentrations have reached to the highest level at the first day of life and have returned to cord level at the third day of life. There were gradually decrease in serum blood urea nitrogen and creatinine levels after the first day of life. There were significant difference in both right and left renal length, width, and volumes in terms of gender and these parameters were statistically higher in boys than girls (p<0.05. Birth weight of the boys (3548±539g was statistically higher than girls (3307±405 g (p=0.028. There was a positive correlation between birth weight and right (r=0.38, p=0.000 and left kidney volumes (r=0.44, p=0.000. Conclusion: Our findings showed that measured blood urea nitrogen and creatinine levels changed in accordance with postnatal days and there was a positive correlation between kidney volume and birth weight of newborns. We concluded that these findings are important for evaluation of acute kidney injury and for screening of for urinary tract anomalies in neonates

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

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Urea, (hexahydro-6-methyl-2... Specific Chemical Substances § 721.9920 Urea, (hexahydro-6-methyl-2-oxopyrimidinyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance urea, (hexahydro-6...

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

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the urea...) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory § 418.30 Applicability; description of the urea subcategory. The provisions of this subpart are applicable to the...

Guidelines for acute management of hyperammonemia in the Middle East region

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Alfadhel M

2016-03-01

extremely obvious.Method: We searched PubMed and Embase databases to include published materials from 2011 to 2014 that were not covered by the European guidelines, which was published in 2012. We followed the process of a Delphi conference and involved one preliminary meeting and two follow-up meetings with email exchanges between the Middle East Hyperammonemia and Urea Cycle Disorders Scientific Group regarding each draft of the manuscript.Results and discussion: We have developed consensus guidelines based on the highest available level of evidence. The aim of these guidelines is to homogenize and harmonize the treatment protocols used for patients with acute hyperammonemia, and to provide a resource to not only metabolic physicians, but also physicians who may come in contact with individuals with acute hyperammonemia.Conclusion: These suggested guidelines aim to ease the challenges faced by physicians dealing with acute hyperammonemia in the region. In addition, guidelines have demonstrated useful collaboration between experts in the region, and provides information that will hopefully improve the outcomes of patients with acute hyperammonemia. Keywords: hyperammonemia, inborn errors of metabolism, urea cycle, acute management, ammonia, Middle East

Feelings of being disabled as a risk factor for mortality up to 8 years after acute myocardial infarction

DEFF Research Database (Denmark)

van der Vlugt, Maureen J; van Domburg, Ron T; Pedersen, Susanne S.

2005-01-01

We examined the independent prognostic value of the four subscales of the Heart Patients Psychological Questionnaire (HPPQ) on mortality in acute myocardial infarction (AMI) survivors up to 8 years after the event.......We examined the independent prognostic value of the four subscales of the Heart Patients Psychological Questionnaire (HPPQ) on mortality in acute myocardial infarction (AMI) survivors up to 8 years after the event....

Urea cycle disorders: brain MRI and neurological outcome.

Science.gov (United States)

Bireley, William R; Van Hove, Johan L K; Gallagher, Renata C; Fenton, Laura Z

2012-04-01

Urea cycle disorders encompass several enzyme deficiencies that can result in cerebral damage, with a wide clinical spectrum from asymptomatic to severe. The goal of this study was to correlate brain MRI abnormalities in urea cycle disorders with clinical neurological sequelae to evaluate whether MRI abnormalities can assist in guiding difficult treatment decisions. We performed a retrospective chart review of patients with urea cycle disorders and symptomatic hyperammonemia. Brain MRI images were reviewed for abnormalities that correlated with severity of clinical neurological sequelae. Our case series comprises six urea cycle disorder patients, five with ornithine transcarbamylase deficiency and one with citrullinemia type 1. The observed trend in distribution of brain MRI abnormalities as the severity of neurological sequelae increased was the peri-insular region first, extending into the frontal, parietal, temporal and, finally, the occipital lobes. There was thalamic restricted diffusion in three children with prolonged hyperammonemia. Prior to death, this site is typically reported to be spared in urea cycle disorders. The pattern and extent of brain MRI abnormalities correlate with clinical neurological outcome in our case series. This suggests that brain MRI abnormalities may assist in determining prognosis and helping clinicians with subsequent treatment decisions.

Urea cycle disorders: brain MRI and neurological outcome

Energy Technology Data Exchange (ETDEWEB)

Bireley, William R. [University of Colorado, Department of Radiology, Aurora, CO (United States); Van Hove, Johan L.K. [University of Colorado, Department of Genetics and Inherited Metabolic Diseases, Aurora, CO (United States); Gallagher, Renata C. [Children' s Hospital Colorado, Department of Genetics and Inherited Metabolic Diseases, Aurora, CO (United States); Fenton, Laura Z. [Children' s Hospital Colorado, Department of Pediatric Radiology, Aurora, CO (United States)

2012-04-15

Urea cycle disorders encompass several enzyme deficiencies that can result in cerebral damage, with a wide clinical spectrum from asymptomatic to severe. The goal of this study was to correlate brain MRI abnormalities in urea cycle disorders with clinical neurological sequelae to evaluate whether MRI abnormalities can assist in guiding difficult treatment decisions. We performed a retrospective chart review of patients with urea cycle disorders and symptomatic hyperammonemia. Brain MRI images were reviewed for abnormalities that correlated with severity of clinical neurological sequelae. Our case series comprises six urea cycle disorder patients, five with ornithine transcarbamylase deficiency and one with citrullinemia type 1. The observed trend in distribution of brain MRI abnormalities as the severity of neurological sequelae increased was the peri-insular region first, extending into the frontal, parietal, temporal and, finally, the occipital lobes. There was thalamic restricted diffusion in three children with prolonged hyperammonemia. Prior to death, this site is typically reported to be spared in urea cycle disorders. The pattern and extent of brain MRI abnormalities correlate with clinical neurological outcome in our case series. This suggests that brain MRI abnormalities may assist in determining prognosis and helping clinicians with subsequent treatment decisions. (orig.)

Urea cycle disorders: brain MRI and neurological outcome

International Nuclear Information System (INIS)

Bireley, William R.; Van Hove, Johan L.K.; Gallagher, Renata C.; Fenton, Laura Z.

2012-01-01

Urea cycle disorders encompass several enzyme deficiencies that can result in cerebral damage, with a wide clinical spectrum from asymptomatic to severe. The goal of this study was to correlate brain MRI abnormalities in urea cycle disorders with clinical neurological sequelae to evaluate whether MRI abnormalities can assist in guiding difficult treatment decisions. We performed a retrospective chart review of patients with urea cycle disorders and symptomatic hyperammonemia. Brain MRI images were reviewed for abnormalities that correlated with severity of clinical neurological sequelae. Our case series comprises six urea cycle disorder patients, five with ornithine transcarbamylase deficiency and one with citrullinemia type 1. The observed trend in distribution of brain MRI abnormalities as the severity of neurological sequelae increased was the peri-insular region first, extending into the frontal, parietal, temporal and, finally, the occipital lobes. There was thalamic restricted diffusion in three children with prolonged hyperammonemia. Prior to death, this site is typically reported to be spared in urea cycle disorders. The pattern and extent of brain MRI abnormalities correlate with clinical neurological outcome in our case series. This suggests that brain MRI abnormalities may assist in determining prognosis and helping clinicians with subsequent treatment decisions. (orig.)

Comparative studies on the mineralization of furfural urea and urea ...

African Journals Online (AJOL)

In this research, laboratory studies were conducted to evaluate the effects of furfural urea as a slow release N fertilizer in an alfisol of Nigeria Savanna in the year 2009/2010 season. Incubation studies revealed that released N through mineralizatoin and microbial activities had confirmed that the compound may stay longer ...

The effects of urea, guanidinium chloride and sorbitol on porphyrin ...

Indian Academy of Sciences (India)

This paper compares the inhibition effect of porphyrin aggregation in the presence of urea, guanidinium chloride (Gdn) and sorbitol by molecular dynamics simulation. It demonstrates that porphyrin aggregation increases in sorbitol, but decreases towards addition of urea and Gdn. It shows that urea, Gdn and sorbitol can ...

Acute Alcohol Intoxication Exacerbates Rhabdomyolysis-Induced Acute Renal Failure in Rats.

Science.gov (United States)

Tsai, Jen-Pi; Lee, Chung-Jen; Subeq, Yi-Maun; Lee, Ru-Ping; Hsu, Bang-Gee

2017-01-01

Traumatic and nontraumatic rhabdomyolysis can lead to acute renal failure (ARF), and acute alcohol intoxication can lead to multiple abnormalities of the renal tubules. We examined the effect of acute alcohol intoxication in a rat model of rhabdomyolysis and ARF. Intravenous injections of 5 g/kg ethanol were given to rats over 3 h, followed by glycerol-induced rhabdomyolysis. Biochemical parameters, including blood urea nitrogen (BUN), creatinine (Cre), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), and creatine phosphokinase (CPK), were measured before and after induction of rhabdomyolysis. Renal tissue injury score, renal tubular cell expression of E-cadherin, nuclear factor-κB (NF-κB), and inducible nitric oxide synthase (iNOS) were determined. Relative to rats in the vehicle group, rats in the glycerol-induced rhabdomyolysis group had significantly increased serum levels of BUN, Cre, GOT, GPT, and CPK, elevated renal tissue injury scores, increased expression of NF-κB and iNOS, and decreased expression of E-cadherin. Ethanol exacerbated all of these pathological responses. Our results suggest that acute alcohol intoxication exacerbates rhabdomyolysis-induced ARF through its pro-oxidant and inflammatory effects.

Effect of paddy urease inhibitors on fate of 15N-urea

International Nuclear Information System (INIS)

Chen Wei; Lu Wanfang

1997-01-01

Urea applied to the paddy field rapidly released ammonium (NH 4 + ) through hydrolysis. The released NH 4 + -N usually reached to a maximum value 2 days after the application. The maximum value was found to be lower and delay 1 day when a mixture of urea and urease inhibitors was applied. Based on 15 N tracing in the urea, it was found that the two urease inhibitors, phenylphosphordiamidate (PPD) and N-(N-butyl) thiophosphoric triamine (NBPT), could enhance the efficiency of urea utilization by rice plants due to more absorption and also stimulated rice growth. The grain yields were higher in the treatments applied with the mixture containing PPD or NBPT, especially at high N level, than that in the treatment applied with urea only. However, the urea inhibitor, hydroquinone (HQ), had far less effect than PPD and NBPT in the experiment. The application of rice straw was found to reduce the urea-N absorption by rice plants but increase its residue in the soil

Long-Term Follow-Up After Endovascular Treatment of Acute Aortic Emergencies

International Nuclear Information System (INIS)

Pitton, M. B.; Herber, S.; Schmiedt, W.; Neufang, A.; Dorweiler, B.; Dueber, C.

2008-01-01

Purpose. To investigate the long-term outcome and efficacy of emergency treatment of acute aortic diseases with endovascular stent-grafts. Methods. From September 1995 to April 2007, 37 patients (21 men, 16 women; age 53.9 ± 19.2 years, range 18-85 years) with acute complications of diseases of the descending thoracic aorta were treated by endovascular stent-grafts: traumatic aortic ruptures (n = 9), aortobronchial fistulas due to penetrating ulcer or hematothorax (n = 6), acute type B dissections with aortic wall hematoma, penetration, or ischemia (n = 13), and symptomatic aneurysm of the thoracic aorta (n = 9) with pain, penetration, or rupture. Diagnosis was confirmed by contrast-enhanced CT. Multiplanar reformations were used for measurement of the landing zones of the stent-grafts. Stent-grafts were inserted via femoral or iliac cut-down. Two procedures required aortofemoral bypass grafting prior to stent-grafting due to extensive arteriosclerotic stenosis of the iliac arteries. In this case the bypass graft was used for introduction of the stent-graft. Results. A total of 46 stent-grafts were implanted: Vanguard/Stentor (n = 4), Talent (n = 31), and Valiant (n = 11). Stent-graft extension was necessary in 7 cases. In 3 cases primary graft extension was done during the initial procedure (in 1 case due to distal migration of the graft during stent release, in 2 cases due to the total length of the aortic aneurysm). In 4 cases secondary graft extensions were performed-for new aortic ulcers at the proximal stent struts (after 5 days) and distal to the graft (after 8 months) and recurrent aortobronchial fistulas 5 months and 9 years after the initial procedure-resulting in a total of 41 endovascular procedures. The 30-day mortality rate was 8% (3 of 37) and the overall follow-up was 29.9 ± 36.6 months (range 0-139 months). All patients with traumatic ruptures demonstrated an immediate sealing of bleeding. Patients with aortobronchial fistulas also demonstrated a

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

Science.gov (United States)

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

2011-08-01

Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature-controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross-over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [(15) N(2) ]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea-N excretion was increased. The ratio of urea-N production to digestible N was increased, whereas the proportion of gut urea-N entry to urea-N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea-N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea-N production and reduction of gut urea-N entry, in relative terms, were associated with increased urinary urea-N excretion of lactating dairy cows in higher thermal environments. 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

Long-term follow-up of patients after acute kidney injury: patterns of renal functional recovery.

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Etienne Macedo

Full Text Available BACKGROUND AND OBJECTIVES: Patients who survive acute kidney injury (AKI, especially those with partial renal recovery, present a higher long-term mortality risk. However, there is no consensus on the best time to assess renal function after an episode of acute kidney injury or agreement on the definition of renal recovery. In addition, only limited data regarding predictors of recovery are available. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: From 1984 to 2009, 84 adult survivors of acute kidney injury were followed by the same nephrologist (RCRMA for a median time of 4.1 years. Patients were seen at least once each year after discharge until end stage renal disease (ESRD or death. In each consultation serum creatinine was measured and glomerular filtration rate estimated. Renal recovery was defined as a glomerular filtration rate value ≥60 mL/min/1.73 m2. A multiple logistic regression was performed to evaluate factors independently associated with renal recovery. RESULTS: The median length of follow-up was 50 months (30-90 months. All patients had stabilized their glomerular filtration rates by 18 months and 83% of them stabilized earlier: up to 12 months. Renal recovery occurred in 16 patients (19% at discharge and in 54 (64% by 18 months. Six patients died and four patients progressed to ESRD during the follow up period. Age (OR 1.09, p<0.0001 and serum creatinine at hospital discharge (OR 2.48, p = 0.007 were independent factors associated with non renal recovery. The acute kidney injury severity, evaluated by peak serum creatinine and need for dialysis, was not associated with non renal recovery. CONCLUSIONS: Renal recovery must be evaluated no earlier than one year after an acute kidney injury episode. Nephrology referral should be considered mainly for older patients and those with elevated serum creatinine at hospital discharge.

A field evaluation of coated urea with biodegradable materials and ...

African Journals Online (AJOL)

ajl yemi

2011-12-28

Dec 28, 2011 ... Urease inhibitor and biodegradable polymer coatings are two most suitable startegies to increase urea fertilizer efficiency. Coating of urea with selected inhibitors can increase the crop production by slowing down the hydrolysis process of urea in the soil. For this purpose, a field experiment was conducted ...

A field evaluation of coated urea with biodegradable materials and ...

African Journals Online (AJOL)

Urease inhibitor and biodegradable polymer coatings are two most suitable startegies to increase urea fertilizer efficiency. Coating of urea with selected inhibitors can increase the crop production by slowing down the hydrolysis process of urea in the soil. For this purpose, a field experiment was conducted to evaluate the ...

Habit modification of epsomite in the presence of urea

Science.gov (United States)

Ramalingom, S.; Podder, J.; Narayana Kalkura, S.; Bocelli, G.

2003-01-01

The pure and urea doped epsomite (MgSO 4·7H 2O) crystals were grown at low temperature by the slow cooling technique. The effect of pH on the growth rate of pure MgSO 4·7H 2O was studied. It was found that the higher pH values increased the growth rate and the size of the crystals. The quantity of urea present in the doped magnesium sulphate crystals was estimated. The incorporation of urea into the mother solution was found to promote the growth rate. The habit of the crystals changed from orthorhombic to tetragonal. Further, there was an increase of microhardness of the crystals on doping of urea.

The incidence of urea cycle disorders

OpenAIRE

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

2013-01-01

A key question for urea cycle disorders is their incidence. In the United States two UCDs argininosuccinic synthetase and lyase deficiency are currently detected by newborn screening. We used newborn screening data on over 6. million births and data from the large US and European longitudinal registries to determine how common these conditions are. The incidence for the United States is predicted to be 1 urea cycle disorder patient for every 35000 births presenting about 113 new patients per ...

Role of carglumic acid in the treatment of acute hyperammonemia due to N-acetylglutamate synthase deficiency

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Häberle J

2011-08-01

Full Text Available Johannes HäberleKinderspital Zürich, Abteilung Stoffwechsel, Zürich, SwitzerlandAbstract: N-acetylglutamate synthase (NAGS deficiency is a rare inborn error of metabolism affecting ammonia detoxification in the urea cycle. The product of NAGS is N-acetylglutamate which is the absolutely required allosteric activator of the first urea cycle enzyme carbamoylphosphate synthetase 1. In defects of NAGS, the urea cycle function can be severely affected resulting in fatal hyperammonemia in neonatal patients or at any later stage in life. NAGS deficiency can be treated with a structural analog of N-acetylglutamate, N-carbamyl-L-glutamate, which is available for enteral use as a licensed drug. Since NAGS deficiency is an extremely rare disorder, reports on the use of N-carbamyl-L-glutamate are mainly based on single patients. According to these, the drug is very effective in treating acute hyperammonemia by avoiding the need for detoxification during the acute metabolic decompensation. Also during long-term treatment, N-carbamyl-L-glutamate is effective in maintaining normal plasma ammonia levels and avoiding the need for additional drug therapy or protein-restricted diet. Open questions remain which concern the optimal dosage in acute and long-term use of N-carbamyl-L-glutamate and potential additional disorders in which the drug might also be effective in treating acute hyperammonemia. This review focuses on the role of N-carbamyl-L-glutamate for the treatment of acute hyperammonemia due to primary NAGS deficiency but will briefly discuss the current knowledge on the role of N-carbamyl-L-glutamate for treatment of secondary NAGS deficiencies.Keywords: carglumic acid, carbamylglutamate, N-carbamyl-L-glutamate, N-acetylglutamate synthase deficiency, NAGS deficiency, hyperammonemia

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

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea-formaldehyde resins in molded articles. 177... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1900 Urea-formaldehyde resins in molded articles. Urea-formaldehyde resins may be safely used as the food-contact surface...

Prognostic factors in neonatal acute renal failure

International Nuclear Information System (INIS)

Chevalier, R.L.; Campbell, F.; Brenbridge, A.N.

1984-01-01

Sixteen infants, 2 to 35 days of age, had acute renal failure, a diagnosis based on serum creatinine concentrations greater than 1.5 mg/dL for at least 24 hours. Eight infants were oliguric (urine flow less than 1.0 mL/kg/h) whereas the remainder were nonoliguric. To determine clinical parameters useful in prognosis, urine flow rate, duration of anuria, peak serum creatinine, urea (BUN) concentration, and nuclide uptake by scintigraphy were correlated with recovery. Nine infants had acute renal failure secondary to perinatal asphyxia, three had acute renal failure as a result of congenital cardiovascular disease, and four had major renal anomalies. Four oliguric patients died: three of renal failure and one of heart failure. All nonoliguric infants survived with mean follow-up serum creatinine concentration of 0.8 +/- 0.5 (SD) mg/dL whereas that of oliguric survivors was 0.6 +/- 0.3 mg/dL. Peak serum creatinine concentration did not differ between those patients who were dying and those recovering. All infants who were dying remained anuric at least four days and revealed no renal uptake of nuclide. Eleven survivors were anuric three days or less, and renal perfusion was detectable by scintigraphy in each case. However, the remaining survivor (with bilateral renal vein thrombosis) recovered after 15 days of anuria despite nonvisualization of kidneys by scintigraphy. In neonates with ischemic acute renal failure, lack of oliguria and the presence of identifiable renal uptake of nuclide suggest a favorable prognosis

Prognostic factors in neonatal acute renal failure

Energy Technology Data Exchange (ETDEWEB)

Chevalier, R.L.; Campbell, F.; Brenbridge, A.N.

1984-08-01

Sixteen infants, 2 to 35 days of age, had acute renal failure, a diagnosis based on serum creatinine concentrations greater than 1.5 mg/dL for at least 24 hours. Eight infants were oliguric (urine flow less than 1.0 mL/kg/h) whereas the remainder were nonoliguric. To determine clinical parameters useful in prognosis, urine flow rate, duration of anuria, peak serum creatinine, urea (BUN) concentration, and nuclide uptake by scintigraphy were correlated with recovery. Nine infants had acute renal failure secondary to perinatal asphyxia, three had acute renal failure as a result of congenital cardiovascular disease, and four had major renal anomalies. Four oliguric patients died: three of renal failure and one of heart failure. All nonoliguric infants survived with mean follow-up serum creatinine concentration of 0.8 +/- 0.5 (SD) mg/dL whereas that of oliguric survivors was 0.6 +/- 0.3 mg/dL. Peak serum creatinine concentration did not differ between those patients who were dying and those recovering. All infants who were dying remained anuric at least four days and revealed no renal uptake of nuclide. Eleven survivors were anuric three days or less, and renal perfusion was detectable by scintigraphy in each case. However, the remaining survivor (with bilateral renal vein thrombosis) recovered after 15 days of anuria despite nonvisualization of kidneys by scintigraphy. In neonates with ischemic acute renal failure, lack of oliguria and the presence of identifiable renal uptake of nuclide suggest a favorable prognosis.

Late-Onset Ornithine Carbamoyltransferase Deficiency Accompanying Acute Pancreatitis and Hyperammonemia

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Marcel Cerqueira Cesar Machado

2013-01-01

Full Text Available Hyperammonemia related to urea cycle disorders is a rare cause of potentially fatal encephalopathy that is encountered in intensive care units (ICUs. Left undiagnosed, this condition may manifest irreversible neuronal damage. However, timely diagnosis and treatment initiation can be facilitated simply by increased awareness of the ICU staff. Here, we describe a patient with acute severe pancreatitis who developed hyperammonemia and encephalopathy without liver disease. Urea cycle disorder was suspected and hemodialysis was initiated. Following reduction of ammonia levels, subsequent treatment included protein restriction and administration of arginine and sodium benzoate. The patient was discharged to home after 47 days with plasma ammonia within normal range and without neurological symptoms. In clinical care settings, patients with neurological symptoms unexplained by the present illness should be assessed for serum ammonia levels to disclose any urea cycle disorders to initiate timely treatment and improve outcome.

Effects of acute changes in salinity and temperature on routine metabolism and nitrogen excretion in gambusia (Gambusia affinis) and zebrafish (Danio rerio).

Science.gov (United States)

Uliano, E; Cataldi, M; Carella, F; Migliaccio, O; Iaccarino, D; Agnisola, C

2010-11-01

Acute stress may affect metabolism and nitrogen excretion as part of the adaptive response that allows animals to face adverse environmental changes. In the present paper the acute effects of different salinities and temperatures on routine metabolism, spontaneous activity and excretion of ammonia and urea were studied in two freshwater fish: gambusia, Gambusia affinis and zebrafish, Danio rerio, acclimated to 27 degrees C. The effects on gill morphology were also evaluated. Five salinities (0 per thousand, 10 per thousand, 20 per thousand, 30 per thousand and 35 per thousand) were tested in gambusia, while four salinities were used in zebrafish (0 per thousand, 10 per thousand, 20 per thousand and 25 per thousand). Each salinity acute stress was tested alone or in combination with an acute temperature reduction to 20 degrees C. In gambusia, both salinity and temperature acute stress strongly stimulated urea excretion. Routine oxygen consumption was barely affected by acute salinity or temperature stress, and was reduced by the combined effects of temperature and high salinity. Gills maintained their structural integrity in all stressing conditions; hyperplasia and hypertrophy of mitochondria-rich cells were observed. In zebrafish, temperature and salinity acute changes, both alone and in combination, scarcely affected any parameter tested. The major effect observed was a reduction of nitrogen excretion at 20 degrees C-25 per thousand; under these extreme conditions a significant structural disruption of gills was observed. These results confirm the high tolerance to acute salinity and temperature stress in gambusia, and demonstrate the involvement of urea excretion modulation in the stress response in this species. Copyright 2010 Elsevier Inc. All rights reserved.

Longitudinal Associations among Renal Urea Clearance-Corrected Normalized Protein Catabolic Rate, Serum Albumin, and Mortality in Patients on Hemodialysis.

Science.gov (United States)

Eriguchi, Rieko; Obi, Yoshitsugu; Streja, Elani; Tortorici, Amanda R; Rhee, Connie M; Soohoo, Melissa; Kim, Taehee; Kovesdy, Csaba P; Kalantar-Zadeh, Kamyar

2017-07-07

There are inconsistent reports on the association of dietary protein intake with serum albumin and outcomes among patients on hemodialysis. Using a new normalized protein catabolic rate (nPCR) variable accounting for residual renal urea clearance, we hypothesized that higher baseline nPCR and rise in nPCR would be associated with higher serum albumin and better survival among incident hemodialysis patients. Among 36,757 incident hemodialysis patients in a large United States dialysis organization, we examined baseline and change in renal urea clearance-corrected nPCR as a protein intake surrogate and modeled their associations with serum albumin and mortality over 5 years (1/2007-12/2011). Median nPCRs with and without accounting for renal urea clearance at baseline were 0.94 and 0.78 g/kg per day, respectively (median within-patient difference, 0.14 [interquartile range, 0.07-0.23] g/kg per day). During a median follow-up period of 1.4 years, 8481 deaths were observed. Baseline renal urea clearance-corrected nPCR was associated with higher serum albumin and lower mortality in the fully adjusted model ( P trend urea clearance-corrected nPCR during the first 6 months was also associated with attaining high serum albumin (≥3.8 g/dl) and lower mortality ( P trend urea clearance, higher levels of renal urea clearance-corrected nPCR consistently showed lower mortality risk. Among incident hemodialysis patients, higher dietary protein intake represented by nPCR and its changes over time appear to be associated with increased serum albumin levels and greater survival. nPCR may be underestimated when not accounting for renal urea clearance. Compared with the conventional nPCR, renal urea clearance-corrected nPCR may be a better marker of mortality. Copyright © 2017 by the American Society of Nephrology.

The emerging role of m-TOR up-regulation in brain Astrocytoma.

Science.gov (United States)

Ryskalin, Larisa; Limanaqi, Fiona; Biagioni, Francesca; Frati, Alessandro; Esposito, Vincenzo; Calierno, Maria Teresa; Lenzi, Paola; Fornai, Francesco

2017-05-01

The present manuscript is an overview of various effects of mTOR up-regulation in astrocytoma with an emphasis on its deleterious effects on the proliferation of Glioblastoma Multiforme. The manuscript reports consistent evidence indicating the occurrence of mTOR up-regulation both in experimental and human astrocytoma. The grading of human astrocytoma is discussed in relationship with mTOR up-regulation. In the second part of the manuscript, the biochemical pathways under the influence of mTOR are translated to cell phenotypes which are generated by mTOR up-regulation and reverted by its inhibition. A special section is dedicated to the prominent role of autophagy in mediating the effects of mTOR in glioblastoma. In detail, autophagy inhibition produced by mTOR up-regulation determines the fate of cancer stem cells. On the other hand, biochemical findings disclose the remarkable effects of autophagy activators as powerful inducers of cell differentiation with a strong prevalence towards neuronal phenotypes. Thus, mTOR modulation acts on the neurobiology of glioblastoma just like it operates in vivo at the level of brain stem cell niches by altering autophagy-dependent cell differentiation. In the light of such a critical role of autophagy we analyzed the ubiquitin proteasome system. The merging between autophagy and proteasome generates a novel organelle, named autophagoproteasome which is strongly induced by mTOR inhibitors in glioblastoma cells. Remarkably, when mTOR is maximally inhibited the proteasome component selectively moves within autophagy vacuoles, thus making the proteasome activity dependent on the entry within autophagy compartment.

Synergistic effect of interleukin 1 alpha on nontypeable Haemophilus influenzae-induced up-regulation of human beta-defensin 2 in middle ear epithelial cells

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Park Raekil

2006-01-01

Full Text Available Abstract Background We recently showed that beta-defensins have antimicrobial activity against nontypeable Haemophilus influenzae (NTHi and that interleukin 1 alpha (IL-1 alpha up-regulates the transcription of beta-defensin 2 (DEFB4 according to new nomenclature of the Human Genome Organization in human middle ear epithelial cells via a Src-dependent Raf-MEK1/2-ERK signaling pathway. Based on these observations, we investigated if human middle ear epithelial cells could release IL-1 alpha upon exposure to a lysate of NTHi and if this cytokine could have a synergistic effect on beta-defensin 2 up-regulation by the bacterial components. Methods The studies described herein were carried out using epithelial cell lines as well as a murine model of acute otitis media (OM. Human cytokine macroarray analysis was performed to detect the released cytokines in response to NTHi exposure. Real time quantitative PCR was done to compare the induction of IL-1 alpha or beta-defensin 2 mRNAs and to identify the signaling pathways involved. Direct activation of the beta-defensin 2 promoter was monitored using a beta-defensin 2 promoter-Luciferase construct. An IL-1 alpha blocking antibody was used to demonstrate the direct involvement of this cytokine on DEFB4 induction. Results Middle ear epithelial cells released IL-1 alpha when stimulated by NTHi components and this cytokine acted in an autocrine/paracrine synergistic manner with NTHi to up-regulate beta-defensin 2. This synergistic effect of IL-1 alpha on NTHi-induced beta-defensin 2 up-regulation appeared to be mediated by the p38 MAP kinase pathway. Conclusion We demonstrate that IL-1 alpha is secreted by middle ear epithelial cells upon exposure to NTHi components and that it can synergistically act with certain of these molecules to up-regulate beta-defensin 2 via the p38 MAP kinase pathway.

Serosal-to-mucosal urea flux across the isolated ruminal epithelium is mediated via urea transporter-B and aquaporins when Holstein calves are abruptly changed to a moderately fermentable diet.

Science.gov (United States)

Walpole, M E; Schurmann, B L; Górka, P; Penner, G B; Loewen, M E; Mutsvangwa, T

2015-02-01

Urea transport (UT-B) proteins are known to facilitate urea movement across the ruminal epithelium; however, other mechanisms may be involved as well because inhibiting UT-B does not completely abolish urea transport. Of the aquaporins (AQP), which are a family of membrane-spanning proteins that are predominantly involved in the movement of water, AQP-3, AQP-7, and AQP-10 are also permeable to urea, but it is not clear if they contribute to urea transport across the ruminal epithelium. The objectives of this study were to determine (1) the functional roles of AQP and UT-B in the serosal-to-mucosal urea flux (Jsm-urea) across rumen epithelium; and (2) whether functional adaptation occurs in response to increased diet fermentability. Twenty-five Holstein steer calves (n=5) were assigned to a control diet (CON; 91.5% hay and 8.5% vitamin and mineral supplement) or a medium grain diet (MGD; 41.5% barley grain, 50% hay, and 8.5% vitamin and mineral) that was fed for 3, 7, 14, or 21 d. Calves were killed and ruminal epithelium was collected for mounting in Ussing chambers under short-circuit conditions and for analysis of mRNA abundance of UT-B and AQP-3, AQP-7, and AQP-10. To mimic physiologic conditions, the mucosal buffer (pH 6.2) contained no urea, whereas the serosal buffer (pH 7.4) contained 1 mM urea. The fluxes of (14)C-urea (Jsm-urea; 26 kBq/10 mL) and (3)H-mannitol (Jsm-mannitol; 37 kBq/10 mL) were measured, with Jsm-mannitol being used as an indicator of paracellular or hydrophilic movement. Serosal addition of phloretin (1 mM) was used to inhibit UT-B-mediated urea transport, whereas NiCl2 (1 mM) was used to inhibit AQP-mediated urea transport. Across treatments, the addition of phloretin or NiCl2 reduced the Jsm-urea from 116.5 to 54.0 and 89.5 nmol/(cm(2) × h), respectively. When both inhibitors were added simultaneously, Jsm-urea was further reduced to 36.8 nmol/(cm(2) × h). Phloretin-sensitive and NiCl2-sensitive Jsm-urea were not affected by diet. The

SERUM AND PAROTID FLUIS UREA-LEVELS IN UNREALOADED HEALTHY YOUNG ADULTS

Science.gov (United States)

Forty-four healthy young adult male subjects were given oral doses of urea, and parotid fluid and serum urea levels were studied for 1 to 3 hours. A...highly significant correlation between urea in serum and in parotid fluid (r equals 0.982) was found. The indication was that, with flow rate...carefully controlled, parotid fluid could be used interchangeably with serum in urea determination, regardless of the magnitude of the blood concentration. (Author)

Effect of sodium chloride intake on urine volume, urinary urea excretion, and milk urea concentration in lactating dairy cattle

NARCIS (Netherlands)

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

2012-01-01

Milk urea nitrogen (MUN; mg of N/dL) has been shown to be related to excretion of urinary urea N (UUN; g of N/d) and total excretion of urinary N (UN; g of N/d) in dairy cows. In the present experiment, it was hypothesized that MUN and the relationship between MUN and UUN or UN is affected by urine

Safety assessment of hydroethanolic rambutan rind extract: acute and sub-chronic toxicity studies.

Science.gov (United States)

Thinkratok, Aree; Suwannaprapha, Parin; Srisawat, Rungrudee

2014-10-01

This study evaluated the safety of rambutan rind extract (RRE) in male Wistar rats. While acute toxicity was evaluated by feeding the rats with single doses of RRE (1000, 2000, 3000, 4000, and 5000 mg/kg) and its sub-chronic toxicity was observed in rats orally administered with RRE (500, 1000, and 2000 mg/kg) daily for 30 days. In acute toxicity study, the LD50 was found to be greater than 5000 mg/kg of RRE. In sub-chronic toxicity study, no mortality and sign of toxicity was found up to 1000 mg/kg/day of RRE. At 2000 mg/kg/day dose, the mortality rate was 12.5%. Significant decreases in body weight gain and food consumption were found in both acute and sub-chronic toxicity studies. In acute toxicity study, all the studied doses of RRE did not alter serum levels of triglyceride (TG), aspartate aminotransferase (AST) andalanine aminotransferase (ALT). In sub-chronic toxicity study, all studied doses of RRE significantly decreased plasma levels of TG and blood urea nitrogen, but did not alter plasma levels of AST and ALT. TC levels did not show any significant change in both the studies. The obtained results provide basic information for in vivo experimental studies of the pharmacological potentiality of RRE.

Differential response of nucleus pulposus intervertebral disc cells to high salt, sorbitol, and urea.

Science.gov (United States)

Mavrogonatou, Eleni; Kletsas, Dimitris

2012-03-01

Nucleus pulposus intervertebral disc cells are routinely confronted with high osmolality in their microenvironment and respond to this stress in vitro by regulating cell cycle progression and by activating a DNA repair machinery in order to counteract its genotoxic effect. In the present study, we attempted to identify the origin of this osmo-regulatory response, by using an ionic NaCl/KCl solution, the compatible osmolyte sorbitol, and the readily permeant urea. High salt and sorbitol were found to activate similar molecular pathways, including the p38 MAPK and the p53-p21(WAF1)-pRb axis, that were not stimulated by high urea. On the other hand, only high urea led to the phosphorylation of ERKs and JNKs. Furthermore, salt- and sorbitol-treated cells were able to phosphorylate histone H2A.X on Ser139, in contrast to cells exposed to urea, indicating a common mechanism for DNA repair, which was achieved by a p53-dependent activation of the G1 checkpoint by both solutes. DNA repair, as directly measured by a host cell reactivation assay, occurred under conditions of hyperosmolar salt and sorbitol, although to a lesser extent in sorbitol-treated cells than in cells exposed to high salinity. Taken as a whole, our findings suggest that the hyperosmolality-provoked DNA damage and the responses of nucleus pulposus cells induced by this genotoxic stress most probably originate from cell volume alterations mediated by hypertonicity and not from increased intracellular ionic concentration. Copyright © 2011 Wiley Periodicals, Inc.

Slow-release urea in supplement fed to beef steers

Directory of Open Access Journals (Sweden)

Ana Paula Gonçalves

2015-02-01

Full Text Available Replacing regular urea (RU by slow-release urea (SRU at two levels of non-protein nitrogen (NPN in concentrate, offered with low-quality roughage, was evaluated in beef steers on dry matter intake (DMI, ruminal fermentation parameters, plasma urea nitrogen (PUN, total tract apparent digestibility of diets and in situ degradability of nitrogen sources. Eight ruminally cannulated steers were allocated into two 4x4 Latin squares, totalizing four treatments: 40 NPN/0 SRU: 40% of concentrate crude protein (CP as NPN, resulting from 0% of SRU and 100% of RU; 40 NPN/50 SRU: 40% of concentrate CP as NPN, resulting from 50% of SRU and 50% of RU; 40 NPN/100 SRU: 40% of concentrate CP as NPN, resulting from 100% of SRU and 0% of RU; 80 NPN/100 SRU: 80% of concentrate CP as NPN, resulting from 100% of SRU and 0% of RU. Results showed that partial substitution of regular urea by slow-release urea did not alter dry matter intake, pattern of ruminal fermentation or plasma urea nitrogen concentrations and increased the total tract apparent digestibility of crude protein in steers diets. The increase in non-protein nitrogen content in crude protein of the concentrate could compromise feed intake and the efficiency of nutrient utilization in the steers fed complete diets based on low quality forage.

The effect of urea and urea-modified halloysite on performance of PCL

Czech Academy of Sciences Publication Activity Database

Khunová, V.; Kelnar, Ivan; Kristóf, J.; Dybal, Jiří; Kratochvíl, Jaroslav; Kaprálková, Ludmila

2015-01-01

Roč. 120, č. 2 (2015), s. 1283-1291 ISSN 1388-6150 R&D Projects: GA ČR(CZ) GA13-15255S Institutional support: RVO:61389013 Keywords : PCL * urea * halloysite Subject RIV: JI - Composite Materials Impact factor: 1.781, year: 2015

Acute myotube protein synthesis regulation by IL-6-related cytokines.

Science.gov (United States)

Gao, Song; Durstine, J Larry; Koh, Ho-Jin; Carver, Wayne E; Frizzell, Norma; Carson, James A

2017-11-01

IL-6 and leukemia inhibitory factor (LIF), members of the IL-6 family of cytokines, play recognized paradoxical roles in skeletal muscle mass regulation, being associated with both growth and atrophy. Overload or muscle contractions can induce a transient increase in muscle IL-6 and LIF expression, which has a regulatory role in muscle hypertrophy. However, the cellular mechanisms involved in this regulation have not been completely identified. The induction of mammalian target of rapamycin complex 1 (mTORC1)-dependent myofiber protein synthesis is an established regulator of muscle hypertrophy, but the involvement of the IL-6 family of cytokines in this process is poorly understood. Therefore, we investigated the acute effects of IL-6 and LIF administration on mTORC1 signaling and protein synthesis in C2C12 myotubes. The role of glycoprotein 130 (gp130) receptor and downstream signaling pathways, including phosphoinositide 3-kinase (PI3K)-Akt-mTORC1 and signal transducer and activator of transcription 3 (STAT3)-suppressor of cytokine signaling 3 (SOCS3), was investigated by administration of specific siRNA or pharmaceutical inhibitors. Acute administration of IL-6 and LIF induced protein synthesis, which was accompanied by STAT3 activation, Akt-mTORC1 activation, and increased SOCS3 expression. This induction of protein synthesis was blocked by both gp130 siRNA knockdown and Akt inhibition. Interestingly, STAT3 inhibition or Akt downstream mTORC1 signaling inhibition did not fully block the IL-6 or LIF induction of protein synthesis. SOCS3 siRNA knockdown increased basal protein synthesis and extended the duration of the protein synthesis induction by IL-6 and LIF. These results demonstrate that either IL-6 or LIF can activate gp130-Akt signaling axis, which induces protein synthesis via mTORC1-independent mechanisms in cultured myotubes. However, IL-6- or LIF-induced SOCS3 negatively regulates the activation of myotube protein synthesis. Copyright © 2017 the

Brain urea increase is an early Huntington's disease pathogenic event observed in a prodromal transgenic sheep model and HD cases.

Science.gov (United States)

Handley, Renee R; Reid, Suzanne J; Brauning, Rudiger; Maclean, Paul; Mears, Emily R; Fourie, Imche; Patassini, Stefano; Cooper, Garth J S; Rudiger, Skye R; McLaughlan, Clive J; Verma, Paul J; Gusella, James F; MacDonald, Marcy E; Waldvogel, Henry J; Bawden, C Simon; Faull, Richard L M; Snell, Russell G

2017-12-26

The neurodegenerative disorder Huntington's disease (HD) is typically characterized by extensive loss of striatal neurons and the midlife onset of debilitating and progressive chorea, dementia, and psychological disturbance. HD is caused by a CAG repeat expansion in the Huntingtin ( HTT ) gene, translating to an elongated glutamine tract in the huntingtin protein. The pathogenic mechanism resulting in cell dysfunction and death beyond the causative mutation is not well defined. To further delineate the early molecular events in HD, we performed RNA-sequencing (RNA-seq) on striatal tissue from a cohort of 5-y-old OVT73 -line sheep expressing a human CAG-expansion HTT cDNA transgene. Our HD OVT73 sheep are a prodromal model and exhibit minimal pathology and no detectable neuronal loss. We identified significantly increased levels of the urea transporter SLC14A1 in the OVT73 striatum, along with other important osmotic regulators. Further investigation revealed elevated levels of the metabolite urea in the OVT73 striatum and cerebellum, consistent with our recently published observation of increased urea in postmortem human brain from HD cases. Extending that finding, we demonstrate that postmortem human brain urea levels are elevated in a larger cohort of HD cases, including those with low-level neuropathology (Vonsattel grade 0/1). This elevation indicates increased protein catabolism, possibly as an alternate energy source given the generalized metabolic defect in HD. Increased urea and ammonia levels due to dysregulation of the urea cycle are known to cause neurologic impairment. Taken together, our findings indicate that aberrant urea metabolism could be the primary biochemical disruption initiating neuropathogenesis in HD.

Effect of Microbial Interaction on Urea Metabolism in Chinese Liquor Fermentation

NARCIS (Netherlands)

Wu, Qun; Lin, Jianchun; Cui, Kaixiang; Du, Rubin; Zhu, Yang; Xu, Yan

2017-01-01

Urea is the primary precursor of the carcinogen ethyl carbamate in fermented foods. Understanding urea metabolism is important for controlling ethyl carbamate production. Using Chinese liquor as a model system, we used metatranscriptome analysis to investigate urea metabolism in spontaneous food

Superspace group descriptions of the symmetries of incommensurate urea inclusion compounds

NARCIS (Netherlands)

vanSmaalen, S; Harris, KDM

1996-01-01

Urea inclusion compounds are a class of incommensurate composite crystals. The urea molecules form a three-dimensionally connected network, with approximate space group symmetry P6(1)22. This network contains tunnels (channels), which accommodate guest molecules. The periodicities of the urea

Renal function and acute heart failure outcome.

Science.gov (United States)

Llauger, Lluís; Jacob, Javier; Miró, Òscar

2018-06-05

The interaction between acute heart failure (AHF) and renal dysfunction is complex. Several studies have evaluated the prognostic value of this syndrome. The aim of this systematic review, which includes non-selected samples, was to investigate the impact of different renal function variables on the AHF prognosis. The categories included in the studies reviewed included: creatinine, blood urea nitrogen (BUN), the BUN/creatinine quotient, chronic kidney disease, the formula to estimate the glomerular filtration rate, criteria of acute renal injury and new biomarkers of renal damage such as neutrophil gelatinase-associated lipocalin (NGAL and cystatin c). The basal alterations of the renal function, as well as the acute alterations, transient or not, are related to a worse prognosis in AHF, it is therefore necessary to always have baseline, acute and evolutive renal function parameters. Copyright © 2018 Elsevier España, S.L.U. All rights reserved.

Environmental factors influencing milk urea nitrogen in South African ...

African Journals Online (AJOL)

p2492989

following fixed effects model, in matrix notation, was used for the ANOVA: .... Estimation of genetic parameters for milk urea nitrogen and its ... urea nitrogen concentration: Heritability and genetic correlations with reproductive performance and.

The incidence of urea cycle disorders.

Science.gov (United States)

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

2013-01-01

A key question for urea cycle disorders is their incidence. In the United States two UCDs, argininosuccinic synthetase and lyase deficiency, are currently detected by newborn screening. We used newborn screening data on over 6million births and data from the large US and European longitudinal registries to determine how common these conditions are. The incidence for the United States is predicted to be 1 urea cycle disorder patient for every 35,000 births presenting about 113 new patients per year across all age groups. © 2013.

Uptake of 15N-labelled urea and 32P-labelled phosphate from acid-based urea phosphate and granular fertilizers

International Nuclear Information System (INIS)

Bole, J.B.

1986-01-01

The availability of nitrogen and phosphorus in fertilizer products labelled with both 32 P and 15 N was measured in a growth chamber experiment. The uptake of N and P by soft white spring wheat (Triticum aestivum L.) from a solution of acid urea phosphate fertilizer did not differ significantly from that of a mixture of granular urea and monammonium phosphate fertilizer. The fertilizer-P uptake efficiency of both sources was higher in a neutral soil than in acid or calcareous soils. Banding either fertilizer increased the uptake of fertilizer P compared with sources mixed with the soil, but did not significantly affect fertilizer-N uptake. The increase in fertilizer-P efficiency due to banding was significantly greater for the urea-monammonium phosphate than for the acid urea phosphate solution. Banding fertilizer did not increase the uptake of fertilizer P in the calcareous soil, and decreased the uptake of fertilizer N in that soil compared with mixed treatments. It is suggested that soluble Ca formed from the reaction of acid with naturally occurring lime may have reduced the availability of fertilizer P in the band

Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism

Science.gov (United States)

Wu, Siva; Li, Xiaojin; Gunawardana, Manjula; Maguire, Kathleen; Guerrero-Given, Debbie; Schaudinn, Christoph; Wang, Charles; Baum, Marc M.; Webster, Paul

2014-01-01

Non-typeable Haemophilus influenzae (NTHi) is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth) stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 µg/mL) of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended. PMID:25007395

Scaling Up Cortical Control Inhibits Pain

Directory of Open Access Journals (Sweden)

Jahrane Dale

2018-05-01

Full Text Available Summary: Acute pain evokes protective neural and behavioral responses. Chronic pain, however, disrupts normal nociceptive processing. The prefrontal cortex (PFC is known to exert top-down regulation of sensory inputs; unfortunately, how individual PFC neurons respond to an acute pain signal is not well characterized. We found that neurons in the prelimbic region of the PFC increased firing rates of the neurons after noxious stimulations in free-moving rats. Chronic pain, however, suppressed both basal spontaneous and pain-evoked firing rates. Furthermore, we identified a linear correlation between basal and evoked firing rates of PFC neurons, whereby a decrease in basal firing leads to a nearly 2-fold reduction in pain-evoked response in chronic pain states. In contrast, enhancing basal PFC activity with low-frequency optogenetic stimulation scaled up prefrontal outputs to inhibit pain. These results demonstrate a cortical gain control system for nociceptive regulation and establish scaling up prefrontal outputs as an effective neuromodulation strategy to inhibit pain. : Dale et al. find that acute pain increases activity levels in the prefrontal cortex. Chronic pain reduces both basal spontaneous and pain-evoked activity in this region, whereas neurostimulation to restore basal activities can in turn enhance nociception-evoked prefrontal activities to inhibit pain. Keywords: chronic pain, neuromodulation, prefrontal cortex, PFC, cortical gain control

A comparison of volume control and pressure-regulated volume control ventilation in acute respiratory failure

OpenAIRE

Guldager, Henrik; Nielsen, Soeren L; Carl, Peder; Soerensen, Mogens B

1997-01-01

Background: The aim of this study was to test the hypothesis that a new mode of ventilation (pressure-regulated volume control; PRVC) is associated with improvements in respiratory mechanics and outcome when compared with conventional volume control (VC) ventilation in patients with acute respiratory failure. We conducted a randomised, prospective, open, cross over trial on 44 patients with acute respiratory failure in the general intensive care unit of a university hospital. After a stabiliz...

Differential Effects of Temperature on Oxygen Consumption and Branchial Fluxes of Urea, Ammonia, and Water in the Dogfish Shark (Squalus acanthias suckleyi).

Science.gov (United States)

Giacomin, Marina; Schulte, Patricia M; Wood, Chris M

Environmental temperature can greatly influence the homeostasis of ectotherms through its effects on biochemical reactions and whole-animal physiology. Elasmobranchs tend to be N limited and are osmoconformers, retaining ammonia and urea-N at the gills and using the latter as a key osmolyte to maintain high blood osmolality. However, the effects of temperature on these key processes remain largely unknown. We evaluated the effects of acute exposure to different temperatures (7°, 12°, 15°, 18°, 22°C) on oxygen consumption, ammonia, urea-N, and diffusive water fluxes at the gills of Squalus acanthias suckleyi. We hypothesized that as metabolic demand for oxygen increased with temperature, the fluxes of ammonia, urea-N, and 3 H 2 O at the gills would increase in parallel with those of oxygen. Oxygen consumption (overall [Formula: see text] from 7.5° to 22°C) and water fluxes (overall [Formula: see text]) responded to increases in temperature in a similar, almost linear, manner. Ammonia-N efflux rates varied the most, increasing almost 15-fold from 7.5° to 22°C ([Formula: see text]). Urea-N efflux was tightly conserved over the 7.5°-15°C range ([Formula: see text]) but increased greatly at higher temperatures, yielding an overall [Formula: see text]. These differences likely reflect differences in the transport pathways for the four moieties. They also suggest the failure of urea-N- and ammonia-N-conserving mechanisms at the gill above 15°C. Hyperoxia did not alleviate the effects of high temperature. Indeed, urea-N and ammonia-N effluxes were dramatically increased when animals were exposed to high temperatures in the presence of hyperoxia, suggesting that high partial pressure of oxygen may have caused oxidative damage to gill epithelial membranes.

The 14C-urea breath-test for the detection of gastric Campylobacter pylori infection

International Nuclear Information System (INIS)

Surveyor, I.; Goodwin, C.S.; Mullan, B.P.; Geelhoed, E.; Warren, J.R.; Murray, R.N.; Waters, T.E.; Sanderson, C.R.

1989-01-01

Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of 14 C -urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of 14 C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with Campylobacter (C.) pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of 14 C-urea in 24 patients with negative microbiological results was 6.9±4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastricbiopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P=0.0001) with the serological antibody test-result. The role of non-invasive tests - enzyme-linked immunosorbent assays and 14 C-urea breath-testing - in the management of gastritis and peptic ulcer disease is discussed. We consider that the 14 C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment. 38 refs., 2 figs., 1 tab

Acute heart failure in the emergency department: a follow-up study.

Science.gov (United States)

Fabbri, Andrea; Marchesini, Giulio; Carbone, Giorgio; Cosentini, Roberto; Ferrari, Annamaria; Chiesa, Mauro; Bertini, Alessio; Rea, Federico

2016-02-01

Acute heart failure (AHF) is a major public health issue due to high incidence and poor prognosis. Only a few studies are available on the long-term prognosis and on outcome predictors in the unselected population attending the emergency department (ED) for AHF. We carried out a 1-year follow-up analysis of 1234 consecutive patients from selected Italian EDs from January 2011 to June 2012 for an episode of AHF. Their prognosis and outcome-associated factors were tested by Cox proportional hazard model. Patients' mean age was 84, with 66.0% over 80 years and 56.2% females. Comorbidities were present in over 50% of cases, principally a history of acute coronary syndrome, chronic obstructive pulmonary disease, diabetes, chronic kidney disease, valvular heart disease. Death occurred within 6 h in 24 cases (1.9%). At 30-day follow-up, death was registered in 123 cases (10.0%): 110 cases (89.4%) died of cardiovascular events and 13 (10.6%) of non-cardiovascular causes (cancer, gastrointestinal hemorrhages, sepsis, trauma). At 1-year follow-up, all-cause death was recorded in 50.1% (over 3 out of 4 cases for cardiovascular origin). Six variables (older age, diabetes, systolic arterial pressure capacity (AUC = 0.649; SE 0.015). Recurrence of AHF was registered in 31.0%. The study identifies a cluster of variables associated with 1-year mortality in AHF, but their predictive capacity is low. Old age and the presence of comorbidities, in particular diabetes are likely to play a major role in dictating the prognosis.

Urea metabolism in Zebu calves fed on diets of dierent crude protein contents

International Nuclear Information System (INIS)

Sharma, P.K.; Singh, U.B.; Verma, D.N.; Lal, M.; Ranjhan, S.K.

1974-01-01

The entry rates of urea into the body pool of urea have been estimated in Zebu calves using a single injection isotope dilution technique using 14 C-urea. The excretion rates of urea were calculated by estimating total urine over 24 h and urea content. The calves were fed 2 levels of crude protein, i.e., 25 percent lower and 25 percent higher than NRC recommendations. Results show that the degradation of urea is significantly better in animals given rations low in crude protein contents. (M.G.B.)

Highly sensitive urea sensing with ion-irradiated polymer foils

International Nuclear Information System (INIS)

Fink, Dietmar; Muñoz Hernandez, Gerardo; Alfonta, Lital

2012-01-01

Recently we prepared urea-sensors by attaching urease to the inner walls of etched ion tracks within thin polymer foil. Here, alternative track-based sensor configurations are examined where the enzyme remained in solution. The conductivities of systems consisting of two parallel irradiated polymer foils and confining different urea/urease mixtures in between were examined. The correlations between conductivity and urea concentration differed strongly for foils with unetched and etched tracks, which points at different sensing mechanisms – tentatively attributed to the adsorption of enzymatic reaction products on the latent track entrances and to the enhanced conductivity of reaction product-filled etched tracks, respectively. All examined systems enable in principle, urea sensing. They point at the possibility of sensor cascade construction for more sensitive or selective sensor systems.

Examining urea flux across the intestine of the spiny dogfish, Squalus acanthias.

Science.gov (United States)

Gary Anderson, W; McCabe, Chris; Brandt, Catherine; Wood, Chris M

2015-03-01

Recent examination of urea flux in the intestine of the spiny dogfish shark, Squalus acanthias, has shown that feeding significantly enhances urea uptake across the intestine, and this was significantly inhibited following mucosal addition of phloretin. The present study examined potential mechanisms of urea uptake across the dogfish intestine in starved and fed dogfish. Unidirectional flux chambers were used to examine the kinetics of urea uptake, and to determine the influence of sodium, ouabain, competitive urea analogues, and phloretin on urea uptake across the gut of fed dogfish. Intestinal epithelial preparations from starved and fed dogfish were mounted in Ussing chambers to examine the effect of phloretin on bidirectional solute transport across the intestine. In the unidirectional studies, the maximum uptake rate of urea was found to be 35.3±6.9 μmol.cm(-2).h(-1) and Km was found to be 291.8±9.6 mM in fed fish, and there was a mild inhibition of urea uptake following mucosal addition of competitive agonists. Addition of phloretin, Na-free Ringers and ouabain to the mucosal side of intestinal epithelia also led to a significant reduction in urea uptake in fed fish. In the Ussing chamber studies there was a net influx of urea in fed fish and a small insignificant efflux in starved fish. Addition of phloretin blocked urea uptake in fed fish when added to the mucosal side. Furthermore, phloretin had no effect on ion transport across the intestinal epithelia with the exception of the divalent cations, magnesium and calcium. Copyright © 2015 Elsevier Inc. All rights reserved.

Studies on nitrogen use efficiency in turmeric using 15N tagged urea

International Nuclear Information System (INIS)

Jagadeeswaran, R.; Arulmozhiselvan, K.; Govindaswamy, M.; Murugappan, V.

2004-01-01

A greenhouse experiment was conducted with turmeric in order to understand the partitioning of N between shoot and rhizome and to study the N use efficiency using 15 N tagged urea. The experiment was conducted in a completely randomized block design with seven treatments consisting of whole N application as basal and split applications ranging from two to six, besides a control. The result indicated that N derived from 15 N urea (Ndff) increased with number of split application of N up to four splits in turmeric shoot and up to three splits in turmeric rhizome, both at 180 days as well as at harvest stage. Increasing the splits beyond this declined Ndff, which indicated that five and more number of splits of N would not help to increase the uptake of applied N. Thus, the present study clearly revealed that in turmeric, application of N in three splits would be optimal in increasing the Ndff in rhizome. Fertilizer N balance calculations clearly indicated that the recovery of N in turmeric was high in favour of four splits at 180 days growth stage (19.46 per cent) as well as at harvest (30.76 per cent). (author)

The structural basis of urea-induced protein unfolding in β-catenin

Science.gov (United States)

Wang, Chao; Chen, Zhongzhou; Hong, Xia; Ning, Fangkun; Liu, Haolin; Zang, Jianye; Yan, Xiaoxue; Kemp, Jennifer; Musselman, Catherine A.; Kutateladze, Tatinna G.; Zhao, Rui; Jiang, Chengyu; Zhang, Gongyi

2014-01-01

Although urea and guanidine hydrochloride are commonly used to denature proteins, the molecular underpinnings of this process have remained unclear for a century. To address this question, crystal structures of β-catenin were determined at various urea concentrations. These structures contained at least 105 unique positions that were occupied by urea molecules, each of which interacted with the protein primarily via hydrogen bonds. Hydrogen-bond competition experiments showed that the denaturing effects of urea were neutralized when polyethylene glycol was added to the solution. These data suggest that urea primarily causes proteins to unfold by competing and disrupting hydrogen bonds in proteins. Moreover, circular-dichroism spectra and nuclear magnetic resonance (NMR) analysis revealed that a similar mechanism caused protein denaturation in the absence of urea at pH levels greater than 12. Taken together, the results led to the conclusion that the disruption of hydrogen bonds is a general mechanism of unfolding induced by urea, high pH and potentially other denaturing agents such as guanidine hydrochloride. Traditionally, the disruption of hydrophobic inter­actions instead of hydrogen bonds has been thought to be the most important cause of protein denaturation. PMID:25372676

Presentation of an acquired urea cycle disorder post liver transplantation.

Science.gov (United States)

Ghabril, Marwan; Nguyen, Justin; Kramer, David; Genco, Trina; Mai, Martin; Rosser, Barry G

2007-12-01

The liver's role as the largest organ of metabolism and the unique and often critical function of liver-specific enzyme pathways imply a greater risk to the recipient of acquiring a donor metabolic disease with liver transplants versus other solid organ transplants. With clinical consequences rarely reported, the frequency of solid organ transplant transfer of metabolic disease is not known. Ornithine transcarbamylase deficiency (OTCD), although rare, is the most common of the urea cycle disorders (UCDs). Because of phenotypic heterogeneity, OTCD may go undiagnosed into adulthood. With over 5000 liver transplant procedures annually in the United States, the likelihood of unknowingly transmitting OTCD through liver transplantation is very low. We describe the clinical course of a liver transplant recipient presenting with acute hyperammonemia and encephalopathy after receiving a liver graft form a donor with unrecognized OTCD. Copyright (c) 2007 AASLD.

REDD1 induction regulates the skeletal muscle gene expression signature following acute aerobic exercise.

Science.gov (United States)

Gordon, Bradley S; Steiner, Jennifer L; Rossetti, Michael L; Qiao, Shuxi; Ellisen, Leif W; Govindarajan, Subramaniam S; Eroshkin, Alexey M; Williamson, David L; Coen, Paul M

2017-12-01

The metabolic stress placed on skeletal muscle by aerobic exercise promotes acute and long-term health benefits in part through changes in gene expression. However, the transducers that mediate altered gene expression signatures have not been completely elucidated. Regulated in development and DNA damage 1 (REDD1) is a stress-induced protein whose expression is transiently increased in skeletal muscle following acute aerobic exercise. However, the role of this induction remains unclear. Because REDD1 altered gene expression in other model systems, we sought to determine whether REDD1 induction following acute exercise altered the gene expression signature in muscle. To do this, wild-type and REDD1-null mice were randomized to remain sedentary or undergo a bout of acute treadmill exercise. Exercised mice recovered for 1, 3, or 6 h before euthanization. Acute exercise induced a transient increase in REDD1 protein expression within the plantaris only at 1 h postexercise, and the induction occurred in both cytosolic and nuclear fractions. At this time point, global changes in gene expression were surveyed using microarray. REDD1 induction was required for the exercise-induced change in expression of 24 genes. Validation by RT-PCR confirmed that the exercise-mediated changes in genes related to exercise capacity, muscle protein metabolism, neuromuscular junction remodeling, and Metformin action were negated in REDD1-null mice. Finally, the exercise-mediated induction of REDD1 was partially dependent upon glucocorticoid receptor activation. In all, these data show that REDD1 induction regulates the exercise-mediated change in a distinct set of genes within skeletal muscle. Copyright © 2017 the American Physiological Society.

Foliar absorption of 15N labeled urea by tea plant

International Nuclear Information System (INIS)

Hoshina, Tsuguo; Kozai, Shuji; Ishigaki, Kozo

1978-01-01

The effect of foliar application on the nitrogen nutrient status of tea shoots has been studied using 15 N labelled urea. Furthermore, the difference in nitrogen utilization by tea plant between foliar applied and top dressed nitrogen was investigated using 15 N labelled urea and ammonium sulfate. The foliar application of urea increased the amount of chlorophyll and total nitrogen in the new shoot, and the foliar application was more effective under shading condition. The urea sprayed upon old leaves prior to the opening of new leaf translocated to the new shoots. However, the foliar application after the opening of new leaf was more effective on nitrogen absorption by new shoots than one prior to that, and rather than top dressing for new shoots. It could be recognized that the foliar application of urea raises the nitrogen nutrient status of tea leaves in summer. (author)

Preparation and characterization of dialdehyde starch urea (DASU ...

African Journals Online (AJOL)

Dialdehyde starch urea (DASU) was prepared by the reaction of dialdehyde starch (DAS) from periodate oxidized cassava starch with urea, which was then used to adsorb Co(II), Pb(II) and Zn(II) ions from aqueous solution. Starch modified starches and starch complexes were characterized by Fourier transform infrared ...

Phosphorus-32 in polycythemia vera with and without maintenance treatment. Intermediate follow-up results; Resultats actuels du protocole de traitement des polyglobulies vraies par le phosphore 32 avec ou sans traitement d`entretien

Energy Technology Data Exchange (ETDEWEB)

Najean, Y.; Rain, J.D. [Hopital Saint-Louis, 75 - Paris (France)

1995-12-31

Three-hundred and seventy-two patients with polycythemia vera, aged 65 years or more or with a high risk of vascular complications, were openly treated between 1979 and 1994 with {sup 32}P or a combination of {sup 32}P plus a small maintenance dose (7,5 mg/kg/day) of hydroxy urea. Although only a small number of patients was followed long enough to allow definite conclusions, some results are already significant in this intermediary study performed in November 1994. Maintenance treatment with hydroxy urea led to a significant prolongation of the intervals between {sup 32}P administrations and to a decreased annual mean dose of radiophosphorus. Median survival does not differ between to the two treatment groups, 10,7 years compared to 10,0 years. The rate of vascular complications did not differ between groups. At 10 years follow-up, the risk of developing (epithelial) cancer was increased in the group of patients who received maintenance treatment, 30% compared to 10%. Similarly, development of myelodysplasia, acute leukemia or lymphoma was more common in patients receiving hydroxy urea, 25% compared to 12%. Myeloid transformation of the spleen occurred with the same frequency. Our intermediate follow-up results show that addition of hydroxy urea to {sup 32}P treatment does not change survival or vascular complications in polycythemia vera patients, but probably increases the risk of developing cancer or leukemia. (authors). 2 refs., 4 figs.

Glucocorticoid up-regulation of high-affinity interleukin 6 receptors on human epithelial cells

International Nuclear Information System (INIS)

Snyers, L.; De Wit, L.; Content, J.

1990-01-01

Interleukin 6 (IL-6) is a potent pleiotropic cytokine, known, among others, to stimulate immunoglobulin production by B cells and to trigger acute-phase protein synthesis by hepatocytes. Similar to IL-1, it is produced by monocytes and macrophages following an inflammatory challenge. Analysis of IL-6 receptor (IL-6R) expression on different human cell lines indicates that dexamethasone could up-regulate the number of IL-6R on one epithelial cell line (UAC) and on two hepatoma cell lines (HepG2 and Hep3B). This effect was confirmed by Scatchard analysis of binding experiments, using [ 35 S]methionine and [ 35 S]cysteine metabolically labeled IL-6. It was confirmed at the level of mRNA expression by Northern blot analysis. These results provide evidence for a link between IL-6 and glucocorticoids. They could represent an example of a system in which one role of glucocorticoids is to define more accurately the target of cytokines, and they could explain, at least partly, the frequently observed synergy between IL-6 and glucocorticoids, notably in the case of hepatocytes

Urea-SCR Temperature Investigation for NOx Control of Diesel Engine

Directory of Open Access Journals (Sweden)

Asif Muhammad

2015-01-01

Full Text Available SCR (selective catalytic reduction system is continuously being analyzed by many researchers worldwide on various concerns due to the stringent nitrogen oxides (NOx emissions legislation for heavy-duty diesel engines. Urea-SCR includes AdBlue as urea source, which subsequently decomposes to NH3 (ammonia being the reducing agent. Reaction temperature is a key factor for the performance of urea-SCR system, as urea decomposition rate is sensitive to a specific temperature range. This particular study was directed to investigate the temperature of the SCR system in diesel engine with the objective to confirm that whether the appropriate temperature is attained for occurrence of urea based catalytic reduction or otherwise and how the system performs on the prescribed temperature range. Diesel engine fitted with urea-SCR exhaust system has been operated on European standard cycle for emission testing to monitor the temperature and corresponding nitrogen oxides (NOx values on specified points. Moreover, mathematical expressions for approximation of reaction temperature are also proposed which are derived by applying energy conservation principal and gas laws. Results of the investigation have shown that during the whole testing cycle system temperature has remained in the range where urea-SCR can take place with best optimum rate and the system performance on account of NOx reduction was exemplary as excellent NOx conversion rate is achieved. It has also been confirmed that selective catalytic reduction (SCR is the best suitable technology for automotive engine-out NOx control.

Fractionation of nitrogen and carbon isotopes by means of urea chromatography

International Nuclear Information System (INIS)

Hirschberg, K.; Krumbiegel, P.; Faust, H.

1981-01-01

Between aqueous urea solutions and strongly acid cation exchange resins of the polystyrene-sulfoacid type a solid-liquid-phase distribution equilibrium develops with an isotope effect of nitrogen and carbon in urea. The [ 13 C, 15 N] urea molecules are preferably bound to the exchanger matrix. The elementary separation factors for 15 N and 13 C enrichment have been determined to be 1.00 per cent. Column chromatographic separation with the aid of Dowex 50 WX8 renders the preparation of double-labelled urea feasible. (author)

Urea nitrate, an exceptionally easy-to-make improvised explosive: studies towards trace characterization.

Science.gov (United States)

Tamiri, Tsippy; Rozin, Rinat; Lemberger, Nitay; Almog, Joseph

2009-09-01

Urea nitrate is a powerful improvised explosive, frequently used by terrorists in the Israeli arena. It was also used in the first World Trade Center bombing in New York in February 1993. It is difficult to identify urea nitrate in post-explosion debris, since only a very small fraction survives the blast. Also, in the presence of water, it readily decomposes to its original components, urea and nitric acid. It is suspected that post-blast debris of urea nitrate can be confused with ammonium nitrate, the main solid product of urea nitrate thermal decomposition. In a comprehensive study towards identification of urea nitrate in post-blast traces, a spectrophotometric technique for quantitative determination of urea nitrate was developed, and conditions were found for extraction and separation of un-exploded traces of urea nitrate with minimal decomposition. Nevertheless, out of 28 samples collected from a series of three controlled firings of urea nitrate charges, only one gave the typical adduct ion by liquid chromatography/mass spectrometry analysis. We found that urea nitrate can be extracted from solid mixtures to organic solvents by using Crown ethers as "host compounds." The adducts thus formed are solid, crystalline compounds that can be characterized by microanalysis and spectroscopic techniques.

Phosphate, urea and creatinine clearances: haemodialysis adequacy assessed by weekly monitoring.

Science.gov (United States)

Debowska, Malgorzata; Wojcik-Zaluska, Alicja; Ksiazek, Andrzej; Zaluska, Wojciech; Waniewski, Jacek

2015-01-01

The specific distribution of phosphate and the control mechanisms for its plasma level makes phosphate kinetics during haemodialysis (HD) considerably different from those of urea and creatinine and makes the quantitative evaluation of adequacy of phosphate removal difficult. We propose the application of equivalent continuous clearance (ECC) as a phosphate adequacy parameter and compare it with ECC for creatinine and urea. Three consecutive dialysis sessions were evaluated for 25 patients on maintenance HD. Concentrations of phosphate, urea and creatinine in plasma were measured every 1h during the treatment and 45 min after, and every 30 min in dialysate. ECC was calculated using the removed solute mass assessed in dialysate and weekly solute profile in plasma. Similar calculations were performed also for the midweek dialysis session only. Different versions of the reference concentration for ECC were applied. ECC with peak average reference concentration was 5.4 ± 1.0 for phosphate, 7.0 ± 1.0 for urea and 4.7 ± 1.0 mL/min for creatinine. ECC for urea and creatinine were well correlated in contrast to the correlations of ECC for phosphate versus urea and creatinine. Midweek ECC were higher than weekly ECC, but they were well correlated for urea and creatinine, but only weakly for phosphate. HD adequacy monitoring for phosphate may be performed using ECC, but it is less predictable than similar indices for urea and creatinine. The values of ECC for phosphate are within the range expected for its molecular size compared with those for urea and creatinine. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Treatment of the syndrome of inappropriate secretion of antidiuretic hormone by urea.

Science.gov (United States)

Decaux, G; Brimioulle, S; Genette, F; Mockel, J

1980-07-01

Recent data have shown the role of urea in the urinary concentrating mechanism. We studied the effects of exogenous urea administration in hyponatremia associated with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). In 20 patients with SIADH, we observed a positive correlation between serum sodium and blood urea levels (r = 0.65; p less than 0.01). In one patient with an oat cell carcinoma and SIADH-induced hyponatremia, we observed the same positive correlation (r = 0.80; p less than 0.01) but also a negative one between the excreted fraction of filtered sodium and urinary urea (r = -0.67; p less than 0.001). The short-term administration of low doses of urea (4 to 10 g) resulted in correcting the "salt-losing" tendency of this patient. Longer term administration of high doses of urea (30 g/day) was attempted with the same patient as well as with a healthy volunteer subject with Pitressin-induced SIADH. in both patients, urea treatment lowered urinary sodium excretion as long as hyponatremia was significant (less than 130 meq/liter). Urea treatment also induced a persistent osmotic diuresis, allowing a normal daily intake of water despite SIADH. This was clearly shown during the long-term treatment of a third patient with SIADH who was taking 30 g urea/day during 11 weeks. It is concluded that urea is a good alternative in the treatment of patients with SIADH who presented with persistent hyponatremia despite the restriction of water intake.

Urea controlled hydrothermal synthesis of ammonium aluminum carbonate hydroxide rods

Science.gov (United States)

Wang, Fang; Zhu, Jianfeng; Liu, Hui

2018-03-01

In this study, ammonium aluminum carbonate hydroxide (AACH) rods were controllably prepared using the hydrothermal method by manipulating the amount of urea in the reaction system. The experimental results showed that AACH in rod shape was able to be gradually transformed from γ-AlOOH in cluster shape during the molar ratios of urea to Al in the reactants were ranged from 8 to 10, and the yield of AACH has increased accordingly. When the molar ratio of urea to Al reaches 11, pure AACH rods with a diameter of 500 nm and a length of 10 μm approximately was able to be produced. Due to the slow decomposition of urea during the hydrothermal reaction, the nucleation and growth of AACH crystal proceed step by step. Therefore, the crystal can fully grow on each crystal plane and eventually produce a highly crystalline rod-shaped product. The role of urea in controlling the morphology and yield of AACH was also discussed in this paper systematically.

Radiation effects on n-hexane-urea inclusion compound

International Nuclear Information System (INIS)

Ohta, Nobuaki; Ozasa, Senichi; Ichikawa, Takahisa

1987-01-01

n-hexane-urea inclusion compounds were γ-irradiated at room temperature and dimers from n-hexane were found to form. Additive effects of 1-hexene, 1-chloropentane, and n-hexylamine to the formation of the dimers have been studied. For the comparison liquid n-hexane systems were also γ-irradiated under the same conditions. The radiation-induced reactions in the inclusion compounds are discussed together with the reactions in the liquid n-hexane systems. The dimers from n-hexane in the inclusion compounds are presumably formed by dimerization of hexyl radicals; the hexyl radicals are possibly produced by hydrogen abstraction of hydrogen atom and/or urea radicals from n-hexane included in urea. (author)

Living with urea stress

Indian Academy of Sciences (India)

Intracellular organic osmolytes are present in certain organisms adapted to harsh environments. These osmolytes protect intracellular macromolecules against denaturing environmental stress. In contrast to the usually benign effects of most organic osmolytes, the waste product urea is a well-known perturbant of ...

Insight into the effect mechanism of urea-induced protein denaturation by dielectric spectroscopy.

Science.gov (United States)

Zhang, Cancan; Yang, Man; Zhao, Kongshuang

2017-12-06

Dielectric relaxation spectroscopy was applied to study how urea affects the phase transition of a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), which has been widely used as a protein model. It was found that there is a pronounced relaxation near 10 GHz for the ternary system of PNIPAM in urea aqueous solution. The temperature dependence of dielectric parameters indicates that urea can reduce the lower critical solution temperature (LCST) of PNIPAM, i.e., stabilize the globule state of PNIPAM and collapse the PNIPAM chains. Based on our results, the interaction mechanism of urea on the conformational transition of PNIPAM was presented: urea replaces water molecules directly bonding with PNIPAM and acts as the bridging agent for the adjacent side chains of PNIPAM. Accordingly, the mechanism with which urea denatures protein was deduced. In addition, it is worth mentioning that, from the temperature dependence of the dielectric parameters obtained in the presence of urea, an interesting phenomenon was found in which the effect of urea on PNIPAM seems to take 2 M as a unit. This result may be the reason why urea and TMAO exit marine fishes at a specific ratio of 2 : 1.

Motion Control of Urea-Powered Biocompatible Hollow Microcapsules.

Science.gov (United States)

Ma, Xing; Wang, Xu; Hahn, Kersten; Sánchez, Samuel

2016-03-22

The quest for biocompatible microswimmers powered by compatible fuel and with full motion control over their self-propulsion is a long-standing challenge in the field of active matter and microrobotics. Here, we present an active hybrid microcapsule motor based on Janus hollow mesoporous silica microparticles powered by the biocatalytic decomposition of urea at physiological concentrations. The directional self-propelled motion lasts longer than 10 min with an average velocity of up to 5 body lengths per second. Additionally, we control the velocity of the micromotor by chemically inhibiting and reactivating the enzymatic activity of urease. The incorporation of magnetic material within the Janus structure provides remote magnetic control on the movement direction. Furthermore, the mesoporous/hollow structure can load both small molecules and larger particles up to hundreds of nanometers, making the hybrid micromotor an active and controllable drug delivery microsystem.

INHIBITION OF SWARMING BY UREA AND ITS DIAGNOSTIC ...

African Journals Online (AJOL)

The anti-swarming property of urea and effects on antibiotic susceptibility among 52 uropathogenic Proteus strains from Lagos, Nigeria were investigated. Urea caused a reduction in swarming and number of swarmed cells at 0.5% (n = 42, DOCZ = 15.5mm), 0.75% (n= 24, DOCZ = 10.7mm), 1% (n = 17, DOCZ = 3.4mm) and ...

Effects of urea foliar application and of ammonium sulphate and urea applied to the soil on yield and N utilization by beans (Phaseolus vulgaris L.)

International Nuclear Information System (INIS)

Muraoka, T.; Victoria, R.L.; Oliveira, J.P.; Boaretto, A.E.

1984-01-01

The effects of nitrogen applied to the soil (as ammonium sulphate and urea) and foliar application of urea supplementing or not the soil application, on bean yield and nitrogen utilization are studied in a cerrado soil. Labelled ammonium sulphate is applied at the rate of 20Kg N/ha at seeding or 15 or 25 days after seeding and 40 Kg N/ha at seeding or in two different applications. Labelled urea is applied at the rate of 20kg N/ha at seeding and 40 Kg N/ha splitted. Foliar application is done at 15,22, 29,36 and 45 days after seeding, with 2% urea solution labelled with 10% 15 N. (M.A.C.) [pt

[Liver transplantation for the treatment of hyperammonemia due to urea cycle disorder: report of four cases].

Science.gov (United States)

Zhu, Zhijun; Sun, Liying; Wei, Lin; Qu, Wei; Zeng, Zhigui; Liu, Ying; Zhang, Liang; He, Enhui; Wang, Dong

2015-02-01

To analyze clinical efficacy and prognosis of liver transplantation in children with hyperammonemia caused by urea cycle disorders. A retrospective analysis was performed on the occurrence of disease, operation and the follow-up post liver transplantation in 4 patients with urea cycle disorders who underwent liver transplantation during June 2001 to May 2014. Four girls were diagnosed with ornithine carbamoyl transferase deficiency by genetic test. They had the clinical onset at the age of 1.5 to 3.0 years. Liver transplantation had been performed at their age of 53.9 months, 40.6 months, 40.3 months and 22.8 months, respectively. The grafts of case 1 and case 2 were from left lateral lobe of liver of cadaveric donor, the graft of case 3 was from left lateral lobe of liver of a living donor, the graft of case 4 was a whole liver of a dead child. The liver function of 4 patients gradually returned to normal, blood ammonia levels were normal and restored the normal diet, 4 children were discharged on postoperative 25-30 days. Regular follow-up was done, the liver function, biochemical features and growth status have been followed up for 162.2 months, 124.2 months, 12.0 months and 4.8 months after liver transplantation, respectively. Now, all the four cases are healthy and growth is normal. Liver transplantation is an important way to the patients with severe hyperammonemia caused by urea cycle disorders. In this study, the patients with ornithine carbamoyl transferase defect got satisfactory long-term outcome after liver transplantation.

The effect of urea on the corrosion behavior of different dental alloys.

Science.gov (United States)

Geckili, Onur; Bilhan, Hakan; Bilgin, Tayfun; Anthony von Fraunhofer, J

2012-01-01

Intraoral corrosion of dental alloys has biological, functional, and esthetic consequences. Since it is well known that the salivary urea concentrations undergo changes with various diseases, the present study was undertaken to determine the effect of salivary urea concentrations on the corrosion behavior of commonly used dental casting alloys. Three casting alloys were subjected to polarization scans in synthetic saliva with three different urea concentrations. Cyclic polarization clearly showed that urea levels above 20 mg/100 ml decreased corrosion current densities, increased the corrosion potentials and, at much higher urea levels, the breakdown potentials. The data indicate that elevated urea levels reduced the corrosion susceptibility of all alloys, possibly through adsorption of organics onto the metal surface. This study indicates that corrosion testing performed in sterile saline or synthetic saliva without organic components could be misleading.

Urea cycle pathway targeted therapeutic action of naringin against ammonium chloride induced hyperammonemic rats.

Science.gov (United States)

Ramakrishnan, Arumugam; Vijayakumar, Natesan

2017-10-01

Ammonia is a well-known neurotoxin that causes liver disease and urea cycle disorder. Excessive ammonia content in the blood leads to hyperammonemic condition and affects both excitatory and inhibitory neurotransmission including brain edema and coma. Naringin, a plant bioflavonoid present in various citrus fruits and mainly extracted from the grape fruit. This study was designed to assess the protective effect of naringin on ammonium chloride (NH 4 Cl) induced hyperammonemic rats. Experimental hyperammonemia was induced by intraperitoneal injections (i.p) of NH 4 Cl (100mg/kg body weight (b.w.)) thrice a week for 8 consecutive weeks. Hyperammonemic rats were treated with naringin (80mg/kg b.w.) via oral gavage. Naringin administration significantly augmented the level of blood ammonia and plasma urea. Naringin also upregulate the expression of urea cycle enzymes such as carbamoyl phosphate synthase I (CPS I) and ornithine transcarbamylase (OTC), arininosuccinate synthase (ASS), argininosuccinate lyase (ASL) and arginase I (ARG) and metabotropic glutamate receptors (mGluRs) such as mGluRs I and mGluRs V and down regulate the expression of inflammatory markers like tumor necrosis factor (TNF-α), nuclear factor kappa B (NF-kB), Interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS). In addition, to this, the protective effect of naringin was also revealed through the immunohistochemical changes in tissues. Thus our present study result suggest that naringin modulates the expression of proteins involved in urea cycle pathway and suppresses the expression of inflammatory markers and acts as a potential agent to treat condition in rats. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Extrinsic nerves are not involved in branchial 5-HT dynamics or pulsatile urea excretion in Gulf toadfish, Opsanus beta.

Science.gov (United States)

Cartolano, Maria C; Amador, Molly H B; Tzaneva, Velislava; Milsom, William K; McDonald, M Danielle

2017-12-01

Gulf toadfish (Opsanus beta) can switch from continuously excreting ammonia as their primary nitrogenous waste to excreting predominantly urea in distinct pulses. Previous studies have shown that the neurotransmitter serotonin (5-HT) is involved in controlling this process, but it is unknown if 5-HT availability is under central nervous control or if the 5-HT signal originates from a peripheral source. Following up on a previous study, cranial nerves IX (glossopharyngeal) and X (vagus) were sectioned to further characterize their role in controlling pulsatile urea excretion and 5-HT release within the gill. In contrast to an earlier study, nerve sectioning did not result in a change in urea pulse frequency. Total urea excretion, average pulse size, total nitrogen excretion, and percent ureotely were reduced the first day post-surgery in nerve-sectioned fish but recovered by 72h post-surgery. Nerve sectioning also had no effect on toadfish urea transporter (tUT), 5-HT transporter (SERT), or 5-HT 2A receptor mRNA expression or 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) abundance in the gill, all of which were found consistently across the three gill arches except 5-HIAA, which was undetectable in the first gill arch. Our findings indicate that the central nervous system does not directly control pulsatile urea excretion or local changes in gill 5-HT and 5-HIAA abundance. Copyright © 2017 Elsevier Inc. All rights reserved.

The Effect of Supplementation Urea and Sulfur in Mixed Cassava Waste Fermented and Soyabean Cake Waste on Digestibility of Protein and Blood Urea Male Sheep

Directory of Open Access Journals (Sweden)

M Bata

1999-05-01

Full Text Available Eighteen local male sheep were divided into 3 groups I,II and III based on the body weight 18.55±1.27, 15.79±0.67 and 13.14±1.33 kg respectively. Two level urea (2 and 3% and three levels Sulfur (0.02 and 0.3% as treatment, so pattern factorial 2x3 with Randomized Block Design used this experiment. All of the treatment get a same basal feed namely land-grass and concentrate with dry matter ratio 70:30.  The total intake of  dry matter was 4 % of body weight. The concentrate consist of cassava waste fermented  and soyabean cake waste with dry matter  ratio 77.50 : 22.50. Supplementation of urea and sulfur shown not significant interaction, but supplementation urea had effect high significantly (P<0.01 on digestibility of protein and sulfur only had effect significant  (P<0.05 on blood urea. These result had indication that enriched urea in the diet could increase protein digestibility and sulfur level 0.2% could prevent NH3 absorption from rumen. (Animal Production 1(2: 75-81 (1999   Key Words: cassava waste, soyabean cake waste, fermentation, digestibility, urea blood.

Long-term dietary restriction up-regulates activity and expression of ...

Indian Academy of Sciences (India)

T Majaw

2017-04-18

Apr 18, 2017 ... Urea, produced by arginase II in the mitochondria, plays a critical role in kidney functions. It serves as an important solute for the development of osmotic gradient in the renal medulla (Bankir et al. 1996; Sands 2007), lowers blood pressure in several rat models by acting as simple osmotic diuretics (Iwata et ...

The effect of virtual cross linking on the oxidative stability and lipid uptake of aliphatic poly(urethane urea).

Science.gov (United States)

Thomas, Vinoy; Jayabalan, Muthu

2002-01-01

In vitro oxidative degradation and lipid sorption of aliphatic, low elastic modulus and virtually cross-linked poly(urethane urea)s based on 4,4' methylene bis(cyclohexyl isocyanate), hydroxy terminated poly butadiene and hexamethylene diamine were evaluated. The aged samples revealed no weight loss in the oxidation medium. The IR spectral analyses revealed the stability of unsaturated double bonds at 964 cm(-1) (characteristic for polybutadiene soft segment) with no change in peak intensity. The poly(tetramethylene glycol) (PTMG)-added poly(ether urethane urea) polymer also revealed no disappearance of IR peaks for ether and unsaturated double bonds in samples aged in vitro oxidation medium. All the polymers have shown increase in weight due to lipid up take in lipid-rich medium (palm oil) but it was rather low in Dulbecco's modified eagle medium (DMEM) cholesterol. The slight change in mechanical properties of the present polymers in oxidation and DMEM is due to the rearrangement of molecular structure with virtual cross links of hydrogen bonding (physical cross linking) without degradation and plasticization effect of lipid. The influence of these media on the rearrangement of virtual cross links has been observed. Higher the virtual cross-link density, lesser is the loss of tensile properties of poly(urethane urea)s in the oxidation medium and vice versa. On the other hand, higher the virtual cross-link density of poly(urethane urea), higher is the loss of ultimate tensile strength and stress at 100% strain and vice versa in DMEM medium.

Dexmedetomidine attenuates pancreatic injury and inflammatory response in mice with pancreatitis by possible reduction of NLRP3 activation and up-regulation of NET expression.

Science.gov (United States)

Li, Yong; Pan, Yiyuan; Gao, Lin; Lu, Guotao; Zhang, Jingzhu; Xie, Xiaochun; Tong, Zhihui; Li, Baiqiang; Li, Gang; Li, Weiqin

2018-01-22

Previous studies have shown that acute inflammation is associated with increased sympathetic activity, which in turn increases the inflammatory response and leads to organ damage. The present study aimed to investigate whether dexmedetomidine administration during acute pancreatitis (AP) lessens pancreatic pathological and functional injury and the inflammatory response, and to explore the underlying mechanisms. Mild pancreatitis was induced in mice with caerulein, and severe pancreatitis was induced with caerulein plus lipopolysaccharide (LPS). After pancreatitis induction, dexmedetomidine at 10 or 20 μg/kg was injected via the tail vein. Pancreatic pathological and functional injury was assessed by histology and serum levels of amylase and lipase, respectively. The inflammatory response was evaluated by determining serum levels of inflammatory factors. The expression of myeloperoxidase (MPO) was examined by immunohistochemistry. The expression of norepinephrine transporter (NET), NLRP3, pro-IL-1β, and interleukin (IL)-1β in pancreatic tissue was detected by Western blot and real-time PCR. Dexmedetomidine at 20 μg/kg significantly attenuated pancreatic pathological injury, reduced serum levels of amylase, lipase, IL-1β, IL-6, and tumor necrosis factor (TNF)-α, and decreased the expression of MPO in pancreatic tissue in both mouse models of pancreatitis. In addition, dexmedetomidine at 20 μg/kg significantly down-regulated the expression of NLRP3, pro-IL-1β, and IL-1β in pancreatic tissue, but up-regulated the expression of NET in both mouse models. Dexmedetomidine attenuates pancreatic injury and inflammatory response in mice with pancreatitis possibly by reducing NLRP3 activation and up-regulating NET expression. Copyright © 2018 Elsevier Inc. All rights reserved.

Toward Understanding Mechanisms Controlling Urea Delivery in a Coastal Plain Watershed

Science.gov (United States)

Tzilkowski, S. S.; Buda, A. R.; Boyer, E. W.; Bryant, R. B.; May, E. B.

2012-12-01

Improved understanding of nutrient mobilization and delivery to surface waters is critical to protecting water quality in agricultural watersheds. Urea, a form of organic nitrogen, is a common nutrient found in fertilizers, manures, and human waste, and is gaining recognition as an important driver of coastal eutrophication, particularly through the development of harmful algal blooms. While several studies have documented elevated urea concentrations in tributaries draining to the Chesapeake Bay, little is known about the potential sources and flow pathways responsible for urea delivery from the landscape to surface waters, as well as how these sources and pathways might vary with changing seasons, antecedent conditions, and storm types. In this study, we investigated hydrologic controls on urea delivery in the Manokin River watershed through the analysis of urea concentration dynamics and hysteresis patterns during seven storm events that occurred in 2010 and 2011. The Manokin River is a Coastal Plain watershed (11.1 km2) on the Delmarva Peninsula that drains directly to the Chesapeake Bay and is characterized by extensive rural development coupled with intensive agriculture, particularly poultry production. Sampling was conducted through monthly grab sampling at baseflow conditions and by time-weighted, automated (Sigma) samplers during stormflow events. Monitored storms were chosen to represent a spectrum of antecedent conditions based on precipitation and groundwater levels in the area. Flushing from the landscape during events was found to be the predominant urea delivery mechanism, as urea concentrations increased 3-9 times above baseflow concentrations during storms. The timing and number of flushes, as well as the degree of increased concentrations were dependent on antecedent conditions and the characteristics of the storm event. For instance, during an intense (13.7 mm hr-1), short-duration (4 hrs) storm in August of 2010 when antecedent conditions were

Urea transporters and sweat response to uremia.

Science.gov (United States)

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

2016-06-01

In humans, urea is excreted in sweat, largely through the eccrine sweat gland. The urea concentration in human sweat is elevated when compared to blood urea nitrogen. The sweat urea nitrogen (UN) of patients with end-stage kidney disease (ESRD) is increased when compared with healthy humans. The ability to produce sweat is maintained in the overwhelming majority of ESRD patients. A comprehensive literature review found no reports of sweat UN neither in healthy rodents nor in rodent models of chronic kidney disease (CKD). Therefore, this study measured sweat UN concentrations in healthy and uremic rats. Uninephrectomy followed by renal artery ligation was used to remove 5/6 of renal function. Rats were then fed a high-protein diet to induce uremia. Pilocarpine was used to induce sweating. Sweat droplets were collected under oil. Sweat UN was measured with a urease assay. Serum UN was measured using a fluorescent ortho-pthalaldehyde reaction. Immunohistochemistry (IHC) was accomplished with a horseradish peroxidase and diaminobenzidine technique. Sweat UN in uremic rats was elevated greater than two times compared to healthy pair-fed controls (220 ± 17 and 91 ± 15 mmol/L, respectively). Post hoc analysis showed a significant difference between male and female uremic sweat UN (279 ± 38 and 177 ± 11 mmol/L, respectively.) IHC shows, for the first time, the presence of the urea transporters UT-B and UT-A2 in both healthy and uremic rat cutaneous structures. Future studies will use this model to elucidate how rat sweat UN and other solute excretion is altered by commonly prescribed diuretics. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

The sup 14 C-urea breath-test for the detection of gastric Campylobacter pylori infection

Energy Technology Data Exchange (ETDEWEB)

Surveyor, I; Goodwin, C S; Mullan, B P; Geelhoed, E; Warren, J R; Murray, R N; Waters, T E; Sanderson, C R [Royal Perth Hospital (Australia)

1989-10-16

Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of {sup 14}C -urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of {sup 14}C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with Campylobacter (C.) pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of {sup 14}C-urea in 24 patients with negative microbiological results was 6.9{plus minus}4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastricbiopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P=0.0001) with the serological antibody test-result. The role of non-invasive tests - enzyme-linked immunosorbent assays and {sup 14}C-urea breath-testing - in the management of gastritis and peptic ulcer disease is discussed. We consider that the {sup 14}C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment. 38 refs., 2 figs., 1 tab.

Crystal growth and properties of novel organic nonlinear optical crystals of 4-Nitrophenol urea

Energy Technology Data Exchange (ETDEWEB)

Mohan, M. Krishna, E-mail: krishnamohan.m@ktr.srmuniv.ac.in; Ponnusamy, S.; Muthamizhchelvan, C.

2017-07-01

Single crystals of 4-Nitrophenol urea have been grown from water using slow evaporation technique at constant temperature, with the vision to improve the properties of the crystals. The unit cell parameters of the grown crystals were determined by single crystal and powder X-Ray diffraction. FTIR studies reveals the presence of different vibrational bands. The Optical studies confirmed that the crystal is transparent up to 360 nm .TGA and DSC studies were carried out to understand the thermal behavior of crystals. The SHG studies show the suitability of the crystals for NLO applications. The etching studies were carried out to study the behavior of the crystals under different conditions.These studies reveal that the crystals of 4-Nitrophenol urea are suitable for device applications. - Highlights: • 4-Nitrophenol urea crystals of dimensions 14 mm × 1 mm were grown. • UV–Visible studies indicate the crystal is transparent in the region of 370–800 nm. • Thermal studies show the crystal starts decomposing at 170 °C. • SHG studies indicate that the crystals have NLO efficiency 3.5 times that of KDP.

Reference Values for Plasma Electrolytes and Urea in Nigerian ...

African Journals Online (AJOL)

Reference values for plasma electrolytes and urea have been defined for Nigerian children and adolescents residing in Abeokuta and its environs, a location in southern Nigeria, by estimating plasma sodium, potassium bicarbonate and urea concentrations in a reference population. The study group comprised three ...

Banding urea and lignosulfonate in corn (Zea mays L.) production and 15N recovery

International Nuclear Information System (INIS)

Alkanani, T.; MacKenzie, A.F.

1996-01-01

The use of urea in corn (Zea mays L.) production is common. Under current N fertilizer recommendations for corn, urea may have adverse effects on corn growth when applied in a band. The effects of ammonium lignosulfonate (LS) on corn growth and on N uptake from the banded application of urea and diammonium phosphate (DAP) mixtures were investigated on two soils from eastern Quebec. Field experiments were initiated in the first week of May 1991 on an Ormstown silty clay and a Ste. Rosalie clay soils (fine, mixed, nonacid, mesic Typic Humaquepts). Treatments were two rates of urea (30 and 90 kg urea-N ha -1 ) in a combination with DAP (14kg N ha 1 ), with or without banded fertilizer solutions of LS (8 kg N ha -1 ) applied at planting 5 cm to the side and 3 cm below the seed. A no treatment control was included. The low rate of urea compared with the unfertilized plots. When compared with the unfertilized treatment, the high rate of urea and DAP (no LS added) caused 10% increase in grain yield. However, addition of LS to the high rate of urea and DAP increase grain yield by band 20%. In general, LS significantly increased corn N uptake from urea on both soils. Separate 15 N field experiments were initiated in June 1991. Mean recovery of 15 N ranged from 17.8% to 30.9% of the applied labelled urea. The rate of urea-N banded had no significant effect on immobilization, but LS resulted in significantly less 15 N immobilized. These observations suggest that LS can reduce the biological immobilization of urea-N and increase the efficiency of urea fertilizer by reducing the negative effects of banding high levels of urea, while attaining benefits of band placement. (author). 29 refs., 6 tabs

Effect of coated urea and non-coated urea on grain yield, N uptake and N distribution in different parts of maize

International Nuclear Information System (INIS)

Ren Yi; Li Guihua; Zhao Linping; Zhang Shuxiang

2011-01-01

In order to regulate nitrogen metabolism with nitrogen application rate and to increase nitrogen use efficiency, an isotopic method was used to compare grain yield, biomass and nitrogen use efficiency of coated urea (CU) to those of non-coated urea (U) at the N application rates of 0, 100, 150 and 225 kg/hm 2 . Results showed that CU significantly increased maize N uptake from 15 N fertilizer and aboveground biomass. The nitrogen use efficiency ( 15 NUE) of CU was 13.3-21.4% greater than that of U. There was a significant different of fertilizer 15 N uptake between CU and U in maize parts. And N uptake of CU treatment followed the order of seed > leaves > straws > cob > husk, while N uptake of U treatment was in the order of seed > straws > leaves > cob > husk. The N uptake of maize parts by both CU and U followed the same order when non-isotopic method was applied. No significant variations were observed among treatments in N uptake, Nitrogen Harvest Index and grain yield. The reason maybe that low soil temperatures (< 10 ℃) from the fourth week of October to next April reduced N uptake of winter wheat, therefore, residual NO3-N in cultivated soil layer was high after harvest. Thus, maize N uptake was more dependent on the shoot growth potential than fertilizer amount and types under high amount of available nitrogen. (authors)

Beta- lactam antibiotics stimulate biofilm formation in non-typeable haemophilus influenzae by up-regulating carbohydrate metabolism.

Directory of Open Access Journals (Sweden)

Siva Wu

Full Text Available Non-typeable Haemophilus influenzae (NTHi is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 µg/mL of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended.

Effect of dietary nitrogen content and intravenous urea infusion on ruminal and portal-drained visceral extraction of arterial urea in lactating Holstein cows

DEFF Research Database (Denmark)

Kristensen, Niels Bastian; Storm, Adam Christian; Larsen, Mogens

2010-01-01

Urea extraction across ruminal and portal-drained visceral (PDV) tissues were investigated using 9 rumen-cannulated and multi-catheterized lactating dairy cows adapted to low-N (12.9% crude protein) and high-N (17.1% crude protein) diets in a crossover design. The interaction between adaptation...... to arterial urea concentrations. Urea extraction increased more across the rumen wall than across the total PDV for low-N compared with high-N, which implies that a larger proportion of total PDV uptake of arterial urea is directed toward the rumen with decreasing N intake. The ruminal vein - arterial (RA......) concentration difference for ammonia increased instantly (first sampling 15 min after initiation of infusion) to the primed intravenous infusion when cows were adapted to the low-N diet. The RA difference for ammonia correlated poorly to the ventral ruminal concentration of ammonia (r = 0.55). Relating the RA...

Ammonia volatilization from surface-applied nitrogen solution of urea and ammonium nitrate

International Nuclear Information System (INIS)

Trivellin, Paulo Cezar Ocheuze; Stefanutti, Ronaldo; Lima Filho, Oscar Fontvo de; Tziboy, Edgar Alfredo Tzi; Oliveira Junior, Jovo Alberto de; Bendassolli, Jose Albertino

1996-08-01

The urea is one of the fertilizers more utilized in modern agriculture. One of the problems in the urea utilization is the ammonium volatilization, resulting in low utilization of N-fertilizers by the plants.The objective of this study it was to evaluate and to compare in laboratories conditions , utilizing the 15 N technic the soil's ammonium lost by volatilization associated a superficial application of nitrogen corresponding doses like urea solution and urea and ammonium nitrates solution

Biosensor Urea Berbasis Biopolimer Khitin Sebagai Matriks Immobilisasi

Directory of Open Access Journals (Sweden)

Nazruddin Nazaruddin

2007-06-01

Full Text Available Penelitian tentang biosensor urea menggunakan biopolimer khitin sebagai matriks immobilisasi telah dilakukan. Penelitian ini dilakukan untuk mengetahui kinerja biosensor yang dihasilkan yang meliputi sensitivitas, trayek pengukuran, limit deteksi, waktu respon, koefisien selektifitas, dan waktu hidup. Penelitian meliputi beberapa tahap yaitu pembuatan membran polimer khitin dan immobilisasi enzim urease, pelekatan membran khitin pada elektroda pH, dan pengukuran parameter kinerja elektroda. Hasil pengukuran menunjukkan sensitivitas biosensor urea berbasis membran khitin adalah 19,11 mV/dekade, trayek pengukuran 10-4 – 10-8 M, limit deteksi 10-8 M, waktu respon 3,10–6,02 menit, dengan urutan kekuatan ion penggangu: NH4Cl > NaCl > CH3COONa > campuran garam > KCl > CaCl2 > asam askorbat. Kata kunci: biosensor, immobilisasi, khitin, urea

Urea enhances cell lysis of Schizosaccharomyces pombe ura4 mutants.

Science.gov (United States)

Nishino, Kohei; Kushima, Misaki; Kaino, Tomohiro; Matsuo, Yasuhiro; Kawamukai, Makoto

2017-07-01

Cell lysis is induced in Schizosaccharomyces pombe ∆ura4 cells grown in YPD medium, which contains yeast extract, polypeptone, and glucose. To identify the medium components that induce cell lysis, we first tested various kinds of yeast extracts from different suppliers. Cell lysis of ∆ura4 cells on YE medium was observed when yeast extracts from OXOID, BD, Oriental, and Difco were used, but not when using yeast extract from Kyokuto. To determine which compounds induced cell lysis, we subjected yeast extract and polypeptone to GC-MS analysis. Ten kinds of compounds were detected in OXOID and BD yeast extracts, but not in Kyokuto yeast extract. Among them was urea, which was also present in polypeptone, and it clearly induced cell lysis. Deletion of the ure2 gene, which is responsible for utilizing urea, abolished the lytic effect of urea. The effect of urea was suppressed by deletion of pub1, and a similar phenotype was observed in the presence of polypeptone. Thus, urea is an inducer of cell lysis in S. pombe ∆ura4 cells.

Nitrogen mineralization and volatilization from controlled release urea fertilizers in selected malaysian soils

International Nuclear Information System (INIS)

Singh, K.J.K.A.; Yusop, M.K.; Oad, F.C.

2017-01-01

Controlled release urea fertilizers are usually used for extended duration in supplying nitrogen. The rate of urea hydrolysis could be efficiently minimized through these fertilizers. Various controlled released fertilizers i.e Uber-10 (30%N), Meister-20 (40%N), Meister-27 (40%N), Humate Coated Urea (45%N), Duration Polymer Coated Urea Type-V (43%N), Gold-N-Sulfur Coated Urea (41%N) and common urea (46%N) were applied to inland soil series of Malaysia. The soil series investigated were: Serdang (Typic Paleudult), Munchong (Typic Hapludox), Segamat (Typic Hapludox), Selangor (Typic Tropaquept), Rengam (Typic Kandiudult) and Holyrood (Typic Kandiudult). The maximum release of ammonium (NH/sub 4/-N) was noted in Gold-N-Sulfur Coated Urea, Humate Coated Urea and common Urea over 8 weeks of incubation. However, the release of NH4-N under the influence of Duration Type-V and Uber-10 took 2nd place. The Meister-20 and Meister-27 had minimum release of NH4-N. Munchong series was efficient in releasing higher NH4-N compared to rest of soils during 8th week of incubation due to higher soil total carbon, low /sub 4/-N and total nitrogen. Ammonia (NH/sub 3/-N) loss progressively increased with unit increase in incubation week and was higher during 6th week of fertilizer application. The higher loss of NH3-N was found in common Urea. However, Meister-20, Meister-27, Duration Polymer Coated Urea Type-V and Uber-10 had lower loss of NH/sub 3/-N due to slow release property and this character could be beneficial for supplying nutrients to next season crop. (author)

A coupled-enzyme equilibrium method for measuring urea in serum: optimization and evaluation of the AACC study group on urea candidate reference method.

Science.gov (United States)

Sampson, E J; Baird, M A; Burtis, C A; Smith, E M; Witte, D L; Bayse, D D

1980-06-01

We describe a coupled-enzyme equilibrium method for measuring urea in serum, which is performed on supernates prepared by treating each specimen with Ba(OH)2 and ZnSO4 (Somogyi reagent). Analytical recovery of [14C]urea added to a variety of matrices was essentially complete (mean, 100.6%) for the supernates after precipitation. Nine variables were univariately examined in arriving at the reaction conditions for the method: glutamate dehydrogenase, urease, 2-oxoglutarate, ADP, Tris . HCI, NADH, EDTA, pH, and temperature. The reagent is stable for at least 48 days at--20 degrees C and for 23 days at 4 degrees C. Mean analytical recovery of urea (14 mmol/L) added to seven different specimens (three different matrices) was 100.8%. The analytical linear range of the method extends to 30 mmol of urea per liter. Of 22 potential interferents, only bilirubin at 1 mmol/L (580 mg/L), hemoglobin at 10 g/L, and hydroxyurea at 6 mmol/L showed more than 2% interference. We discuss precision and effects of specimen dilution, and compare results for 100 human serum specimens with those measured for the same specimens with four other urea methods. We examined the effects of measuring a blank, consisting of sample and reagent without urease, with each specimen.

Study of furfural-urea grout

Energy Technology Data Exchange (ETDEWEB)

1980-01-01

An analysis of raw materials, formulation and performance of furfural-urea grout is given. Characteristics of the grout slurry, mechanism of stabilization and examples of shaft sinking with grouting in quicksand are summarized.

Role of urea in the postprandial urine concentration cycle of the insectivorous bat Antrozous pallidus.

Science.gov (United States)

Bassett, John E

2004-02-01

Insectivorous bats, which feed once daily, produce maximally concentrated urine only after feeding. The role of urea as an osmolyte in this process was investigated in pallid bats (Antrozous pallidus) in the laboratory. Following a 24-h fast, plasma and urine were sampled before and 2 h after feeding in postprandial (PP) animals and before and 2 h after similar treatment without feeding in nonfed (NF) animals. Food consumption by PP animals and handling of NF animals had no effect on blood water content as measured by hematocrit and plasma oncotic pressure. Food consumption increased both plasma osmolality (P(osm)) and plasma urea (P(urea)) by as much as 15%. Food consumption also increased urine osmolality (U(osm)) and urine urea (U(urea)) by 50-100%. Feeding increased U(osm) regardless of changes in P(osm), and elevation of U(osm) resulted primarily from increased U(urea). In NF bats, P(osm) and P(urea) were unchanged, while U(osm) and U(urea) increased by as much as 25%. Again, increased U(osm) resulted primarily from increased U(urea). The PP urine concentration cycle of pallid bats resulted from increased urea excretion in response to apparent rapid urea synthesis. Bats rapidly metabolized protein and excreted urea following feeding when body water was most plentiful.

Impact of urease inhibitors on utilization efficiency of N-urea in rice paddy

International Nuclear Information System (INIS)

Chen Wei; Lu Wanfang

1998-01-01

Urea applied to the paddy field rapidly released ammonium (NH 4 + ) through hydrolysis. The released NH 4 + -N was usually at peak two days after the application. The peak was found to be lower and delay one day when a mixture of urea and urease inhibitors was applied. Based on tracing of 15 N in the urea used, the two urease inhibitors, phenylphosphordiamidate (PPD) and N-(N-butyl) thiophosphoric triamide (NBPT), were found to enhance the efficiency of urea utilization by rice plants due to more absorption and also stimulate rice growth. The grain yields in the treatments applied with the mixture containing PPD or NBPT were higher, particularly at high N level, than that in the treatment applied with urea only. However, the urea inhibitor, hydroquinone (HQ), displayed far less effect than PPD and NBPT in the experiment. The application of rice straw was found to decrease the absorption of rice plants to N in urea but increase its residue in the soil

A colorimeter for measurement of picomole quantities of urea.

Science.gov (United States)

Vurek, G G; Knepper, M A

1982-04-01

We described a new colorimeter for the measurement of picomole quantities of urea in nanoliter volume fluid samples. The diacetyl monoxime reaction was used to produce a colored product from urea. The method is capable of resolving differences of 10 pmoles between samples containing 0 to 225 pmoles.

Up-regulation of β-adrenoreceptors by drugs which cause depression

International Nuclear Information System (INIS)

Brand, L.; Van Rooyen, J.M.; Offermeier, J.

1988-01-01

A number of drugs associated with depressive episodes in man were investigated for their effects on rat cortical β-adrenoceptors, in view of the down-regulation of β-adrenoceptors caused by chronic administration of anti-depressant drugs. Scatchard analyses of [ 3 H]dihydro-alprenolol binding data provided B max and K D values for the cortical β-adrenoceptors. Up-regulation of the receptors occurred after daily injections of phenobarbitone for seven days (by 55%), pentobarbitone (by 143%), reserpine (by 82%) and propranolol (by 64%). β-adrenoceptors were not affected by daily injections of clonidine, chlorpromazine and flupenthixol for seven days. This work confirms the up-regulatory effect on β-adrenoceptors of certain drugs which produce depressions in man

Degradation mechanism and thermal stability of urea nitrate below the melting point

International Nuclear Information System (INIS)

Desilets, Sylvain; Brousseau, Patrick; Chamberland, Daniel; Singh, Shanti; Feng, Hongtu; Turcotte, Richard; Anderson, John

2011-01-01

Highlights: → Decomposition mechanism of urea nitrate. → Spectral characterization of the decomposition mechanism. → Thermal stability of urea nitrate at 50, 70 and 100 o C. → Chemical balance of decomposed products released. - Abstract: Aging and degradation of urea nitrate below the melting point, at 100 o C, was studied by using thermal analysis and spectroscopic methods including IR, Raman, 1 H and 13 C NMR techniques. It was found that urea nitrate was completely degraded after 72 h at 100 o C into a mixture of solids (69%) and released gaseous species (31%). The degradation mechanism below the melting point was clearly identified. The remaining solid mixture was composed of ammonium nitrate, urea and biuret while unreacted residual nitric and isocyanic acids as well as traces of ammonia were released as gaseous species at 100 o C. The thermal stability of urea nitrate, under extreme storage conditions (50 o C), was also examined by isothermal nano-calorimetry.

Comparison of urea space, deuterium oxide space and body composition in growing pigs

International Nuclear Information System (INIS)

Mitchell, A.D.; Steele, N.C.

1987-01-01

Urea and deuterium oxide (D 2 O) space were compared by simultaneous infusion into pigs weighing approximately 55 or 90 kg. Urea was cleared from the plasma pool more rapidly than D 2 O and appeared to equilibrate at a relative concentration which was lower than that of D 2 O. Consequently, urea and D 2 O space values were closest when extrapolated to zero time values. Correlations between urea space and D 2 O space were highest at 15 minutes post infusion (R2 = .75) or between urea space at 15 minutes and D 2 O at equilibrium (R2 = .86). Results of urea and D 2 O space measurements were compared with water, lipid and protein content of the carcass. Urea space at 15 minutes and D 2 O space at 35 minutes most closely approximated total body water while D 2 O space at 15 minutes was nearly equivalent to empty body water. Overall, D 2 O space at equilibrium had the highest correlations with carcass values of water, lipid and protein and appears to be preferable to urea space for estimating carcass composition in pigs

Response of maize to reduced urea application combined with compound nitrogen fertilizer synergists

International Nuclear Information System (INIS)

Tian Xiuying; WANG Zhengyin

2006-01-01

Pot and field experiments were conducted to study the response to application rate of urea labeled with 15 N combined with compound nitrogen fertilizer synergists in the growth, yield, uptake and utilization rate of urea of maize. In pot experiment, the standard urea application rate is 120 mg/perpot; in field experiment, the standard urea application rate is 157.5 kg/hm 2 . Maize with 15 N-urea. The results showed that the growth of maize seedling was obviously promoted with appropriate dosage of compound nitrogen fertilizer synergists (20%-60% of N). The treatments of urea application rate reduced by 5%-15% and added compound nitrogen fertilizer synergists, the growth and nitrogen content of maize were not significant changed, and the total 15 N uptake and nitrogen uptake by maize were the same as CK 2 or increased a little. Nitrogen use efficiency of other treatments increased by 5.6%-7.3% comparing with CK, except the treatment of urea application rate reduced by 30%. The apparent utilization rate of nitrogen was enhanced by 7.7%-17.0%. Under the field condition, maize yield, total uptake, net uptake, physiological rate and agronomic use efficiency of nitrogen were the same as CK or increased. The apparent utilization rate of nitrogen was enhanced by 14.8%-15.2% treated with urea reduced by 5%-15% (7.8-23.7 kg/hm 2 ) and added with compound nitrogen fertilizer synergists. It was not helpful for the growth and nitrogen utilization rate of maize when urea reduced by 30% and combined with compound nitrogen fertilizer synergists. As a result, treated with urea decreased by 15% and combined with appropriate dosage of compound nitrogen fertilizer synergists (20% of urea), the growth and yield of maize had litter effect and higher the uptake and utilization of nitrogen. (authors)

Is acute recurrent pancreatitis in children a precursor of chronic pancreatitis? A long-term follow-up study of 93 cases.

Science.gov (United States)

Poddar, Ujjal; Yachha, Surender K; Borkar, Vibhor; Srivastava, Anshu

2017-07-01

In view of paucity of literature we analyzed our experience of acute recurrent pancreatitis (ARP) to study clinical profile and long-term outcome. Over 13 years, 93 consecutive children (≤18 years) diagnosed to have ARP were included in this study. Magnetic resonance cholangiopancreatography was done at baseline and on follow-up. Common mutations for serine-protease-inhibitor (SPINK1 N34S), protease inhibitor (PRSS1 R122S) and cystic fibrosis transmembrane conductance regulator (CFTR deltaF508, 5T) were studied in 22 idiopathic cases. The median age of the children with ARP was 13 (10-14.5) years, 53 were males. Etiology included biliary in 14 (15%), pancreas divisum in 6 (7%), others in 3 (3.5%) and idiopathic in the remaining 70 (75%). SPINK1 mutation was found in 10/22 (45%) cases. Over a median follow-up of 25.5 (8.25-48) months, 37 (42%) of 88 (5 lost to follow-up) developed chronic pancreatitis (CP). On multivariate analysis idiopathic etiology (petiology and presence of genetic mutations. Hence, patients with ARP should be kept on regular follow-up to detect CP. Copyright © 2017 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Acute and chronic rejection: compartmentalization and kinetics of counterbalancing signals in cardiac transplants.

Science.gov (United States)

Kaul, A M K; Goparaju, S; Dvorina, N; Iida, S; Keslar, K S; de la Motte, C A; Valujskikh, A; Fairchild, R L; Baldwin, W M

2015-02-01

Acute and chronic rejection impact distinct compartments of cardiac allografts. Intramyocardial mononuclear cell infiltrates define acute rejection, whereas chronic rejection affects large arteries. Hearts transplanted from male to female C57BL/6 mice undergo acute rejection with interstitial infiltrates at 2 weeks that resolve by 6 weeks when large arteries develop arteriopathy. These processes are dependent on T cells because no infiltrates developed in T cell-deficient mice and transfer of CD4 T cells restored T cell as well as macrophage infiltrates and ultimately neointima formation. Markers of inflammatory macrophages were up-regulated in the interstitium acutely and decreased as markers of wound healing macrophages increased chronically. Programmed cell death protein, a negative costimulator, and its ligand PDL1 were up-regulated in the interstitium during resolution of acute rejection. Blocking PDL1:PD1 interactions in the acute phase increased interstitial T cell infiltrates. Toll-like receptor (TLR) 4 and its endogenous ligand hyaluronan were increased in arteries with neointimal expansion. Injection of hyaluronan fragments increased intragraft production of chemokines. Our data indicate that negative costimulatory pathways are critical for the resolution of acute interstitial infiltrates. In the arterial compartment recognition of endogenous ligands including hyaluronan by the innate TLRs may support the progression of arteriopathy. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

Effect of urea on the photoactivity of titania powder prepared by sol-gel method

International Nuclear Information System (INIS)

Cheng Ping; Deng Changsheng; Gu Mingyuan; Dai Xiaming

2008-01-01

The synthesis of nanocrystalline titania powders from the hydrolysis of Ti(OBu n ) 4 in the presence of urea was investigated. DRS results showed that a redshift occurred in the absorption edge of titania with increasing the content of urea. XRD results indicated that urea showed a retarding effect on the transformation of titania from anatase to rutile. Moreover, the addition of urea resulted in a higher Brunauer-Emmett-Teller (BET) surface area as well as a larger average pore size of TiO 2 nanoparticles. The average pore size of urea/TiO 2 gels calcined at 500 deg. C increased with the increase of urea content, while the specific surface area increased with the amount of urea to reach a maximum at 10% and then decreased with further increase of the amount of urea. The maximal specific surface area of 64.4 m 2 g -1 was obtained for 10% urea/TiO 2 gels calcined at 500 deg. C, which showed an average particle size of 15 nm and pore size distribution in the range of mesopores centered at 5.8 nm. The photocatalytic experiments exhibited that titania nanoparticles prepared in the presence of urea could effectively photodegrade methyl orange under visible light irradiation due to the redshift of the absorption edge. The maximum photoactivity was achieved when the content of urea was 10%, which was attributed to the higher specific surface area

Relationship between plasma uridine and urinary urea excretion.

Science.gov (United States)

Ka, Tuneyoshi; Inokuchi, Taku; Tamada, Daisuke; Suda, Michio; Tsutsumi, Zenta; Okuda, Chihiro; Yamamoto, Asako; Takahashi, Sumio; Moriwaki, Yuji; Yamamoto, Tetsuya

2010-03-01

To investigate whether the concentration of uridine in plasma is related to the urinary excretion of urea, 45 healthy male subjects with normouricemia and normal blood pressure were studied after providing informed consent. Immediately after collection of 24-hour urine, blood samples were drawn after an overnight fast except for water. The contents of ingested foods during the 24-hour urine collection period were described by the subjects and analyzed by a dietician. Simple regression analysis showed that plasma uridine was correlated with the urinary excretions of urea (R = 0.41, P urea. These results suggest that an increase in de novo pyrimidine synthesis leads to an increased concentration of uridine in plasma via nitrogen catabolism in healthy subjects with normouricemia and normal blood pressure. (c) 2010 Elsevier Inc. All rights reserved.

Acute Toxicity of Delsate® Herbicide (Glyphosate) On Albumin and ...

African Journals Online (AJOL)

Some biochemical metabolism [albumin and blood urea nitrogen (BUN)] were monitored in the serum of fresh water adult African Catfish, Clarias gariepinus exposed to acute concentrations of Delsate herbicide for 96 hours. The concentrations of the toxicant tested were 0.5 mgL-1, 1.0 mgL-1, 1.5 mgL-1, 2.0 mgL-1 and 2.5 ...

Oxidation of urea-derived nitrogen by thaumarchaeota-dominated marine nitrifying communities.

Science.gov (United States)

Tolar, Bradley B; Wallsgrove, Natalie J; Popp, Brian N; Hollibaugh, James T

2017-12-01

Urea nitrogen has been proposed to contribute significantly to nitrification by marine thaumarchaeotes. These inferences are based on distributions of thaumarchaeote urease genes rather than activity measurements. We found that ammonia oxidation rates were always higher than oxidation rates of urea-derived N in samples from coastal Georgia, USA (means ± SEM: 382 ± 35 versus 73 ± 24 nmol L -1  d -1 , Mann-Whitney U-test p  0.05). Urea-derived N was relatively more important in samples from Antarctic continental shelf waters, though the difference was not statistically significant (19.4 ± 4.8 versus 12.0 ± 2.7 nmol L -1  d -1 , p > 0.05). We found only weak correlations between oxidation rates of urea-derived N and the abundance or transcription of putative Thaumarchaeota ureC genes. Dependence on urea-derived N does not appear to be directly related to pH or ammonium concentrations. Competition experiments and release of 15 NH 3 suggest that urea is hydrolyzed to ammonia intracellularly, then a portion is lost to the dissolved pool. The contribution of urea-derived N to nitrification appears to be minor in temperate coastal waters, but may represent a significant portion of the nitrification flux in Antarctic coastal waters. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Effect of diet and physiological state on recycling of urea in Merino ...

African Journals Online (AJOL)

Abstract. The recycling of urea to the rumen was studied in Merino ewes during differentp hysiologicals tates using radioactivet racers. The results showed that although the proportion of urea recycled differed, similar amounts were recycled in dry and pregnant sheep over a wide range of N intake. Urea recycling increased ...

Effect of diet anil physiological state on recycling of urea in Merino ...

African Journals Online (AJOL)

The recycling of urea to the rumen was studied in Merino ewes during different physiological states using radioactive tracers. The results showed that although the proportion of urea recycled differed, similar amounts were recycled in dry and pregnant sheep over a wide range of N intake. Urea recycling increased ...

Acute Psychosocial Stress and Emotion Regulation Skills Modulate Empathic Reactions to Pain in Others

Directory of Open Access Journals (Sweden)

Gabriele eBuruck

2014-05-01

Full Text Available Psychosocial stress affects resources for adequate coping with environmental demands. A crucial question in this context is the extent to which acute psychosocial stressors impact empathy and emotion regulation. In the present study, 120 participants were randomly assigned to a control group vs. a group confronted with the Trier Social Stress Test, an established paradigm for the induction of acute psychosocial stress. Empathy for pain as a specific subgroup of empathy was assessed via pain intensity ratings during a pain-picture task. Self-reported emotion regulation skills were measured as predictors using an established questionnaire. Stressed individuals scored significantly lower on the appraisal of pain pictures. A regression model was chosen to find variables that further predict the pain ratings. These findings implicate that acute psychosocial stress might impair empathic processes to observed pain in another person and the ability to accept one’s emotion additionally predicts the empathic reaction. Furthermore, the ability to tolerate negative emotions modulated the relation between stress and pain judgments, and thus influenced core cognitive-affective functions relevant for coping with environmental challenges. In conclusion, our study emphasizes the necessity of reducing negative emotions in terms of empathic distress when confronted with pain of another person under psychosocial stress, in order to be able to retain pro-social behavior.

Renewable urea sensor based on a self-assembled polyelectrolyte layer.

Science.gov (United States)

Wu, Zhaoyang; Guan, Lirui; Shen, Guoli; Yu, Ruqin

2002-03-01

A renewable urea sensor based on a carboxylic poly(vinyl chloride) (PVC-COOH) matrix pH-sensitive membrane has been proposed, in which a positively charged polyelectrolyte layer is first constructed by using a self-assembly technique on the surface of a PVC-COOH membrane, and urease, with negative charges, is then immobilized through electrostatic adsorption onto the PVC-COOH membrane, by controlling the pH of the urease solution below its isoelectric point. The response characteristics of the PVC-COOH pH-sensitive membrane and the effects of experimental conditions have been investigated in detail. Compared with conventional covalent immobilization, the urea sensor made with this self-assembly immobilization shows significant advantage in terms of sensitivity and ease of regeneration. The potential responses of the urea sensor with self-assembly immobilization increase with the urea concentration over the concentration range 10(-5) - 10(-1) mol l(-1), and the detection limit is 0.028 mmol(-1). Moreover, this type of urea sensor can be repeatedly regenerated by using a simple washing treatment with 0.01 mol l(-1) NaOH (containing 0.5 mol l(-1) NaCl) and 0.01 mol l(-1) HCl. The urease layers and the polyelectrolyte layers on the PVC-COOH membrane are removed, the potential response of the sensor to urea solutions of different concentrations returns nearly to zero, and another assembly cycle of urease and polyelectrolyte can then be carried out.

effect of combined use of urea and goat dung manure on celosia

African Journals Online (AJOL)

Three field experiments were conducted to investigate the separate and combined effects of urea and goat dung manure on leaf nutrient contents, growth and yield of Celosia argentea in southwest Nigeria. Each experiment involved 7 treatments namely: no treatment, 10t/ha goat dung, 125 kg/ha urea, 125 kg/ha urea + ...

Biochemical markers and neuropsychological functioning in distal urea cycle disorders.

Science.gov (United States)

Waisbren, Susan E; Cuthbertson, David; Burgard, Peter; Holbert, Amy; McCarter, Robert; Cederbaum, Stephen

2018-02-08

Urea cycle disorders often present as devastating metabolic conditions, resulting in high mortality and significant neuropsychological damage, despite treatment. The Urea Cycle Disorders Longitudinal Study is a natural history study that collects data from regular clinical follow-up and neuropsychological testing. This report examines links between biochemical markers (ammonia, glutamine, arginine, citrulline) and primary neuropsychological endpoints in three distal disorders, argininosuccinic acid synthetase deficiency (ASD or citrullinemia type I), argininosuccinic acid lyase deficiency (ASA or ALD), and arginase deficiency (ARGD). Laboratory results and test scores from neuropsychological evaluations were assessed in 145 study participants, ages 3 years and older, with ASD (n = 64), ASA (n = 65) and ARGD (n = 16). Mean full scale IQ was below the population mean of 100 ± 15 for all groups: (ASD = 79 ± 24; ASA = 71 ± 21; ARGD = 65 ± 19). The greatest deficits were noted in visual performance and motor skills for all groups. While ammonia levels remain prominent as prognostic biomarkers, other biomarkers may be equally valuable as correlates of neuropsychological functioning. Cumulative exposure to the biomarkers included in the study proved to be highly sensitive indicators of neuropsychological outcomes, even when below the cut-off levels generally considered toxic. Blood levels of biomarkers obtained on the day of neuropsychological evaluations were not correlated with measures of functioning for any disorder in any domain. The importance of cumulative exposure supports early identification and confirms the need for well-controlled management of all biochemical abnormalities (and not just ammonia) that occur in urea cycle disorders.

Urea-induced binding between diclofenac sodium and bovine serum albumin: a spectroscopic insight.

Science.gov (United States)

Dohare, Neeraj; Khan, Abbul Bashar; Athar, Fareeda; Thakur, Sonu Chand; Patel, Rajan

2016-06-01

We investigated the interaction of diclofenac sodium (Dic.Na) with bovine serum albumin (BSA) in the absence and presence of urea using different spectroscopic techniques. A fluorescence quenching study revealed that the Stern-Volmer quenching constant decreases in the presence of urea, decreasing further at higher urea concentrations. The binding constant and number of binding sites were also evaluated for the BSA-Dic.Na interaction system in the absence and presence of urea using a modified Stern-Volmer equation. The binding constant is greater at high urea concentrations, as shown by the fluorescence results. In addition, for the BSA-Dic.Na interaction system, a static quenching mechanism was observed, which was further confirmed using time-resolved fluorescence spectroscopy. UV-vis spectroscopy provided information about the formation of a complex between BSA and Dic.Na. Circular dichroism was carried out to explain the conformational changes in BSA induced by Dic.Na in the absence and presence of urea. The presence of urea reduced the α-helical content of BSA as the Dic.Na concentration varied. The distance r between the donor (BSA) and acceptor (Dic.Na) was also obtained in the absence and presence of urea, using fluorescence resonance energy transfer. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Serum Albumin Is Independently Associated with Persistent Organ Failure in Acute Pancreatitis

Directory of Open Access Journals (Sweden)

Wandong Hong

2017-01-01

Full Text Available Background and Aims. To investigate the association between serum albumin levels within 24 hrs of patient admission and the development of persistent organ failure in acute pancreatitis. Methods. A total of 700 patients with acute pancreatitis were enrolled. Multivariate logistic regression and subgroup analysis determined whether decreased albumin was independently associated with persistent organ failure and mortality. The diagnostic performance of serum albumin was evaluated by the area under Receiver Operating Characteristic (ROC curves. Results. As levels of serum albumin decrease, the risk of persistent organ failure significantly increases (Ptrend<0.001. The incidence of organ failure was 3.5%, 10.6%, and 41.6% in patients with normal albumin and mild and severe hypoalbuminaemia, respectively. Decreased albumin levels were also proportionally associated with prolonged hospital stay (Ptrend<0.001 and the risk of death (Ptrend<0.001. Multivariate analysis suggested that biliary etiology, chronic concomitant diseases, hematocrit, blood urea nitrogen, and the serum albumin level were independently associated with persistent organ failure. Blood urea nitrogen and the serum albumin level were also independently associated with mortality. The area under ROC curves of albumin for predicting organ failure and mortality were 0.78 and 0.87, respectively. Conclusion. A low serum albumin is independently associated with an increased risk of developing of persistent organ failure and death in acute pancreatitis. It may also be useful for the prediction of the severity of acute pancreatitis.

Quantifying why urea is a protein denaturant, whereas glycine betaine is a protein stabilizer

Science.gov (United States)

Guinn, Emily J.; Pegram, Laurel M.; Capp, Michael W.; Pollock, Michelle N.; Record, M. Thomas

2011-01-01

To explain the large, opposite effects of urea and glycine betaine (GB) on stability of folded proteins and protein complexes, we quantify and interpret preferential interactions of urea with 45 model compounds displaying protein functional groups and compare with a previous analysis of GB. This information is needed to use urea as a probe of coupled folding in protein processes and to tune molecular dynamics force fields. Preferential interactions between urea and model compounds relative to their interactions with water are determined by osmometry or solubility and dissected using a unique coarse-grained analysis to obtain interaction potentials quantifying the interaction of urea with each significant type of protein surface (aliphatic, aromatic hydrocarbon (C); polar and charged N and O). Microscopic local-bulk partition coefficients Kp for the accumulation or exclusion of urea in the water of hydration of these surfaces relative to bulk water are obtained. Kp values reveal that urea accumulates moderately at amide O and weakly at aliphatic C, whereas GB is excluded from both. These results provide both thermodynamic and molecular explanations for the opposite effects of urea and glycine betaine on protein stability, as well as deductions about strengths of amide NH—amide O and amide NH—amide N hydrogen bonds relative to hydrogen bonds to water. Interestingly, urea, like GB, is moderately accumulated at aromatic C surface. Urea m-values for protein folding and other protein processes are quantitatively interpreted and predicted using these urea interaction potentials or Kp values. PMID:21930943

Comparison of ammonium sulfate and urea as nitrogen sources in rice production

International Nuclear Information System (INIS)

Bufogle, A. Jr.; Bollich, P.K.; Kovar, J.L.; Lindau, C.W.; Macchiavellid, R.E.

1998-01-01

Wetland rice agriculture is the major anthropogenic source of methane, an important greenhouse gas. Methane emissions are less when ammonium sulfate (AS) rather than urea is the nitrogen (N) source. However, an agronomic advantage of AS over urea has not been established. The objectives of this study were: (i) to compare the effectiveness of AS, urea, and urea plus elemental sulfur (S) as sources of N in flooded rice culture, (ii) to compare fertilizer recovery of each source of N from application at preflood (PF) and panicle initiation (PI), and (iii) to determine if there is a response to S by rice grown on a soil with a less than optimum level of available S. 'Cypress' rice was drill-seeded in a Crowley silt loam soil (fine, montmorillonitic, thermic Typic Albaqualf) of 7.25 to 10.75 mg S kg-1. Ammonium sulfate, urea, or urea plus S was applied in split applications of 101 kg N ha-1 PF and 50 kg N ha-1 PI. Microplots with retainers and 15N-labeled N were used. Unlabeled N was used in field plots. Microplots were harvested at 50% heading, while field plots were harvested at maturity. Dry matter and total N accumulation at 50% heading and at maturity were similar regardless of N source. Grain dry matter yields were 8.54, 8.47, and 8.79 Mg ha-1 for AS, urea, and urea plus S treatments, respectively. Greater N recovery was generally found from N application at PI than at PF, but this was not reflected by an increase in grain yield. No response to S was detected, although grain yields were slightly higher when S-containing fertilizers were used. Ammonium sulfate and urea were equally effective for flooded rice production in Louisiana

INFLUENCE OF ENVIRONMENTAL AND GENETICAL FACTORS ON UREA CONTENT IN HOLSTEIN BREED COWS MILK

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Draženko Budimir

2014-12-01

Full Text Available The aims of this paper were to determine to which extent the environmental factors (order and stadium of lactation, age with the first calving, calving season, region and herd have the influence on the content of urea in milk, and connection of urea content in milk with other features of milk production with cows. The largest share of urea content in milk was recorded in the first lactation, in the period between 110 and 140 days, when it was around 23.6 mg/100 ml. In the end of the first lactation the average urea content in milk was around 21.6 mg/100 ml. The second lactation is chara¬cterized by somewhat bigger urea content, in the period immediately after calving when the highest values from all tracked lactations was recorded. The age of cows with their first calving also had an impact on urea con¬tent in milk. Cows that calved in the age from 24th to 26th month had the highest value of urea content, being 23.2 mg/100 ml for the stated period. The lowest value of urea content was recorded with cows that calved in the age of 18 months and it was below 20 mg/100 ml. Season of calving also influenced the urea content in milk. In winter season 2004 the lowest values of urea content in milk were recorded while in the autumn sea¬son of the same year the highest urea content in milk was measured (24 mg/100 ml. In the following calving season increase of urea content in milk followed. The differences in urea content in milk were determined between the counties. The highest value of heritabi-lity (0.08 was estimated by the model where, as a comparison group, the interaction between the herds and control day was used. In the research the share of variability was explained by the interaction herd-control day and it was 67%, while 25% of variability of urea con¬tent in milk remained unexplained. This model was used when estimating the breeding values. A model was also tested where the influence of herd was used as a comparison group, and by this

76 FR 77015 - Solid Urea From Russia and Ukraine

Science.gov (United States)

2011-12-09

... Urea From Russia and Ukraine Determination On the basis of the record \\1\\ developed in the subject five... orders on solid urea from Russia and Ukraine would be likely to lead to continuation or recurrence of material injury to an industry in the United States within a reasonably foreseeable time.\\2\\ \\1\\ The record...

Influence of an azolla layer on growth, production and efficiency and use of 15N Labelled urea fertilizer of lowland rice

International Nuclear Information System (INIS)

Hendrarti, Etty; Sopandie, Didy; Komarudin Idris; Sisworo, Elsje L

1998-01-01

The purpose of this experiment was to study the effect of an Azolla mat on rice growth, percentage of N-total, N derived from fertilizer and urea efficiency. The experiment used a factorial design which consists of 2 factors : the using of an Azolla mat and the doses of N fertilizer. The first factor comprised 2 levels, with (A1) and without an azolla mat (A0). The second factor comprised 4 levels, 0(N0), 30 (N1), 60(N2) and 90 kg N/ha(N3).Application of 15 N labeled Urea done to determine percentage N-derived from Urea efficiency , which was divided in 2 experiment series as follows : application Urea at planting (experiment I) and one month after planting (experiment II). The experiments were carried out in the green house of Agricultural Faculty of IPB and continued in the laboratory of BATAN. Parameters observed were plant height, number of tillers, number of panicles, number of grains/panicle, dry weight of grain, straw and percentage of empty grain. Result of the experiment showed that an Azolla mat, the doses of N fertilizer and interaction of both increased all the parameters observed yield, except for percentage of empathy grain, up to the dose of N fertilizer at 60 kg N/ha and decreased at the dose of N fertilizer at 90 kg N/ha. The treatment of Urea fertilizer doses resulted in a significant difference on the percentage of N- derived from Urea for both experiment, but not for the treatment of an Azolla mat and the interaction of both treatment. An azolla mat, N fertilizer and interaction of both did not result in a significantly difference on the percentage of total-N and Urea efficiency. The best treatment combination was treatment of an azolla mat and dose of Urea fertilizer of 60 kg N/ha. (author)

Urea production by yeasts other than Saccharomyces in food fermentation

NARCIS (Netherlands)

Wu, Qun; Cui, Kaixiang; Lin, Jianchun; Zhu, Yang; Xu, Yan

2017-01-01

Urea is an important intermediate in the synthesis of carcinogenic ethyl carbamate in various food fermentations. Identifying urea-producing microorganisms can help control or reduce ethyl carbamate production. Using Chinese liquor fermentation as a model system, we identified the yeasts responsible

A Facile Method for the Preparation of Unsymmetrical Ureas Utilizing Zirconium(IV) Chloride

International Nuclear Information System (INIS)

Lee, Anna; Kim, Hee-Kwon; Thompson, David H.

2016-01-01

A facile synthetic method for the preparation of unsymmetrical ureas from amines is described.Carbamoyl imidazole compounds were prepared by the reaction of 1,1-carbonyldiimidazole with primary or secondary amines, and further activation by treatment with zirconium(IV) chloride to generate the desired urea. This reaction protocol was applied to the synthesis of tri and tetrasubstituted ureas with high yields. This study provides an alternative guideline for the practical preparation of various unsymmetrical ureas.

Metal-Free Conversion of Carboxamides to Ureas Using Tertiary Amines and Iodosylmesitylene

Energy Technology Data Exchange (ETDEWEB)

Han, Hoon; Chang, Suk Bok [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2010-03-15

A new synthetic route has been developed for the preparation of ureas from the reaction of carboxamides with tertiary amines with the use of iodosylmesitylene as a stoichiometric oxidant. Although the reaction proceeds under the mild conditions to afford urea products in moderate yields, further optimization studies are required to improve the reaction efficiency and regioselectivity in the dealkylative pathway. Ureas are recognized as an important synthetic building unit, finding a wide range of applications in the preparation of agrochemicals, petrochemicals, and pharmaceuticals. In addition, hydrogen bond-mediated communication between ureas and certain types of compounds is an important structural motif in asymmetric catalysis, molecular recognition, and crystal engineering. Although numerous procedures have been developed for the urea synthesis, the most commonly employed strategy involves the reaction of amine precursors with phosgene, or its surrogates, isocyanates, or carbamates. Whereas these traditional methods are operative under conventional reaction conditions, they often lead to incomplete conversion. Additional drawback of these protocols is that unsymmetric ureas are difficult to prepare in many cases.

Android integrated urea biosensor for public health awareness

Directory of Open Access Journals (Sweden)

Pranali P. Naik

2015-03-01

Full Text Available Integration of a biosensor with a wireless network on the Android 4.2.1 (Jelly Bean platform has been demonstrated. The present study reports an android integrated user friendly Flow injection analysis-Enzyme thermistor (FIA-ET urea biosensor system. This android-integrated biosensor system will facilitate enhanced consumer health and awareness alongside abridging the gap between the food testing laboratory and the concerned higher authorities. Data received from a flow injection mode urea biosensor has been exploited as an integration point among the analyst, the food consumer and the responsible higher authorities. Using the urea biosensor as an example, an alarm system has also been demonstrated both graphically and through text message on a mobile handset. The presented sensor integrated android system will also facilitate decision making support system in various fields of food quality monitoring and clinical analysis.

Urea biosensor for hemodialysis monitoring

Science.gov (United States)

Glass, Robert S.

1999-01-01

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

Errors in Computing the Normalized Protein Catabolic Rate due to Use of Single-pool Urea Kinetic Modeling or to Omission of the Residual Kidney Urea Clearance.

Science.gov (United States)

Daugirdas, John T

2017-07-01

The protein catabolic rate normalized to body size (PCRn) often is computed in dialysis units to obtain information about protein ingestion. However, errors can manifest when inappropriate modeling methods are used. We used a variable volume 2-pool urea kinetic model to examine the percent errors in PCRn due to use of a 1-pool urea kinetic model or after omission of residual urea clearance (Kru). When a single-pool model was used, 2 sources of errors were identified. The first, dependent on the ratio of dialyzer urea clearance to urea distribution volume (K/V), resulted in a 7% inflation of the PCRn when K/V was in the range of 6 mL/min per L. A second, larger error appeared when Kt/V values were below 1.0 and was related to underestimation of urea distribution volume (due to overestimation of effective clearance) by the single-pool model. A previously reported prediction equation for PCRn was valid, but data suggest that it should be modified using 2-pool eKt/V and V coefficients instead of single-pool values. A third source of error, this one unrelated to use of a single-pool model, namely omission of Kru, was shown to result in an underestimation of PCRn, such that each ml/minute Kru per 35 L of V caused a 5.6% underestimate in PCRn. Marked overestimation of PCRn can result due to inappropriate use of a single-pool urea kinetic model, particularly when Kt/V <1.0 (as in short daily dialysis), or after omission of residual native kidney clearance. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

G-CSF maintains controlled neutrophil mobilization during acute inflammation by negatively regulating CXCR2 signaling

Science.gov (United States)

Bajrami, Besnik; Zhu, Haiyan; Zhang, Yu C.

2016-01-01

Cytokine-induced neutrophil mobilization from the bone marrow to circulation is a critical event in acute inflammation, but how it is accurately controlled remains poorly understood. In this study, we report that CXCR2 ligands are responsible for rapid neutrophil mobilization during early-stage acute inflammation. Nevertheless, although serum CXCR2 ligand concentrations increased during inflammation, neutrophil mobilization slowed after an initial acute fast phase, suggesting a suppression of neutrophil response to CXCR2 ligands after the acute phase. We demonstrate that granulocyte colony-stimulating factor (G-CSF), usually considered a prototypical neutrophil-mobilizing cytokine, was expressed later in the acute inflammatory response and unexpectedly impeded CXCR2-induced neutrophil mobilization by negatively regulating CXCR2-mediated intracellular signaling. Blocking G-CSF in vivo paradoxically elevated peripheral blood neutrophil counts in mice injected intraperitoneally with Escherichia coli and sequestered large numbers of neutrophils in the lungs, leading to sterile pulmonary inflammation. In a lipopolysaccharide-induced acute lung injury model, the homeostatic imbalance caused by G-CSF blockade enhanced neutrophil accumulation, edema, and inflammation in the lungs and ultimately led to significant lung damage. Thus, physiologically produced G-CSF not only acts as a neutrophil mobilizer at the relatively late stage of acute inflammation, but also prevents exaggerated neutrophil mobilization and the associated inflammation-induced tissue damage during early-phase infection and inflammation. PMID:27551153

Effect of urea level and treating time on ruminal degradability of urea-treated rice straw evaluated by in sacco method

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Promma, S.

2006-07-01

Full Text Available An experiment was conducted to evaluate the dry matter disappearance and potential degradability of urea-treated rice straw (UTS. Five kg of non-glutinous rice straw (RS was chopped and treated with urea solution and kept in a double sheet polyethylene bag. The ratio of RS to water was 1:1. The urea concentration was 4, 5 and 6% by weight of RS and the duration of treatment was 7, 14 and 21 days. There were 9 treatment combinations with 3 replications. The dry and ground UTS were weighted into nylon bags and incubated in 3 fistulated cows. The dry matter disappearance was detected at different incubation times. The result showed that CP content of UTS was higher than RS and the amount increased with the increasing level of urea. The longer treatment duration caused depletion in CP content. Nitrogen was lost as ammonia when UTS was dried, which led to the lower CP than fresh UTS. The duration of treating of 7, 14 and 21 days caused no-significant difference in potential degradability (71.61±2.59, 72.38±2.80 and 72.70±2.44%, respectively, P> 0.05, but 6% UTS has higher potential degradability than 4 % UTS (74.24± 0.53 and 69.84±1.03%, respectively, P< 0.05

Ammonia Volatilization in Cocoa Farm as Affected by Sugarcane Filter Cake Supply at Different Urea and Soil Moisture Levels

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Erwin Prastowo

2015-02-01

Full Text Available Ammonia  (NH3  volatilization  is  a  crucial  mechanism  in  soil  nitrogen  (N cycle. It accounts for main loss  of N in cocoa  farms  when  environment is  suitable to  promote  the  emission.  A  research  to  locate  a  link  of  several  factors,  namely, sugarcane filter cake  (SFC, urea  and soil moisture content  to NH 3 volatilization,  and  to reveal  cocoa  N  uptake  and  urea  fertilizer  efficiency  was  taken  place  both  in  a laboratory  with  the  incubation  technique,  and  in  a  greenhouse  as  a  pot  trial. The design was completely randomized design in factorial. The soil was Inceptisol from Kaliwining Experimental Station, Jember, East Java, collected from top soil of  a  productive  cocoa  farm.  A  closed  trap  system  was  designed  to  measurevolatilized  NH 3 from  soil  and  SFC  mixture  incubated  for  14  days.  For  the  pot experiment,  cocoa  clone  of  Scavina  6  seedlings  were  grown  for  six  months  withtreatments  involving  series  level  of  SFC  and  series  level  of  urea.  Soil  moisture content influenced volatilized NH3 by reducing 50% emission in where it was more obvious in higher level of urea applied. It was more than 90% in average for the increase in volatilized NH 3roduced by increasing in level of urea from 0 to 0.4 g kg -1 in  overall  level  of  combinations. An increase in urea  level  had  resulted in increase in  soil  pH, and  Parson correlation suggested a direct  link  with  volatilized  NH 3  We found  a  relationship  between  SFC  and volatilized  NH 3 and  their combinations  with soil  moisture  and  urea  content  were  able  to  inhibit  the  emission.  Emission decrease  up  to  28%  was  observed  from  0  to  100  g  SFC  kg-1.  This  inhibition may  have contributed to  the increase in  N cocoa  plant uptake

Rate of recurrence in Indian patients presenting with acute pancreatitis and identification of chronicity on follow up: Possible risk factors for progression.

Science.gov (United States)

Kalaria, Rishikesh; Abraham, Philip; Desai, Devendra C; Joshi, Anand; Gupta, Tarun

2018-03-01

To study the profile and long-term outcome of Indian patients presenting with acute pancreatitis and the possible risk factors for progression. Consecutive patients with acute or recurrent acute pancreatitis seen in our department during July 2013 to December 2014 were included. Details of past episodes were collected and patients were followed up till March 2015. In the 97 patients included (mean age 47.2 [SD 16.9] years; 74 men), gallstones (37 [38.1%]) and alcohol (19 [19.6%]) were the major identified etiologies; the idiopathic (31 [32%]) group constituted a third of patients. Recurrences were more common with idiopathic etiology (14 patients out of 30 had recurrences [46.7%]) as compared to alcoholic (5 out of 19 [26.3%]) and biliary (4 out of 37 [10.8%]) pancreatitis and with mild index episode. Following the episode of acute pancreatitis, identification of chronic pancreatitis was more common with alcoholic (6 out of 18 [33%]) and idiopathic (9 out of 30 [30%]) etiology as compared to other etiologies. Longer duration of follow up, but not number of recurrent episodes, was associated with identification of chronicity in patients presenting as acute pancreatitis. Out of 97 patients with acute pancreatitis, 27 (27.8%) developed recurrences with risk factors being idiopathic etiology and mild index episode. Eighteen of 97 (18.6%) patients had evidence of chronic pancreatitis on follow up, risk factors being the alcoholic and idiopathic varieties, and longer duration of follow up.

75 FR 51440 - Solid Urea from the Russian Federation: Final Results of Antidumping Duty Administrative Review

Science.gov (United States)

2010-08-20

... DEPARTMENT OF COMMERCE International Trade Administration [A-821-801] Solid Urea from the Russian... duty order on solid urea from the Russian Federation. The solid urea subject to this review was... solid urea from the Russian Federation. See Solid Urea From the Russian Federation: Preliminary Results...

Agricultural production - Phase 2. Indonesia. Application of molasses-urea blocks to ruminant production in Indonesia

International Nuclear Information System (INIS)

Leng, R.A.

1991-01-01

This report summarizes briefly the accomplishments of a Coordinated Research Program to increase ruminant productivity in Indonesia by the application of urea-molasses blocks. The technology is highly cost effective and readily accepted by farmers. Suggestions are made for a three-year follow-up project to investigate the productivity of ruminants fed with packaged rice straw. 6 photographs

The Kinetics of Urea in the Body after Liver Resection in the Experiment

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P. N. Savilov

2016-01-01

Full Text Available Purpose. To study urea kinetics in the body after liver resection in the experiment.Material and Methods. Experiments were carried out on 45 white female rats weighing between 180 g and 220 g. Liver resection (LR was performed under ester anesthesia, wherein 15—20% of the organ weight was removed. Urea content was studied in biological fluids (arterial blood, venous — v.porta, v.hepatica, v.renalis — blood, choledochal bile, urine, and tissues of visceral organs (the thyroid gland, lungs, heart, liver, kidneys, spleen, stomach, intestine on days 3, 7, and 14 after LR. Results. LR, while reducing the urea content in the v. hepatica blood, does not lead to similar changes in the arterial blood. This is accompanied by increased urea reabsorption in kidneys and higher v.porta blood urea content, which, depending on the postoperative time, results either from reduced urea excretion into the small intestine lumen or from its greater production by enterocytes followed by metabolite intake into the portal blood flow. The urea intake from hepatocytes into the hepatic bile ducts did not change on day 3 after LR; however, it increased on day 7 and slowed down on day 14. LR caused no changes in the gastric tissues urea content; never theless, it led to its increased content in the duodenal and colonic tissues. Without affecting the cardiac muscleurea content, LR entailed its increase in the lungs and thyroid gland on postoperative days 3, 7, and 14. At the background of absence of similar changes in the arterial blood data indicates promotion of urea production by the cells of these organs or metabolite retention therein.Conclusions. LR not only changes urea kinetics in the portal system organs, but also activates extrahepatic mechanisms aimed at preventing development of the arterial blood urea deficit because of its abnormal intake from the resected organ into the central blood flow.

76 FR 66690 - Solid Urea From the Russian Federation: Final Results of Antidumping Duty Administrative Review

Science.gov (United States)

2011-10-27

... DEPARTMENT OF COMMERCE International Trade Administration [A-821-801] Solid Urea From the Russian... duty order on solid urea from the Russian Federation. The solid urea subject to this review was... administrative review of the antidumping duty order on solid urea from the Russian Federation. See Solid Urea...

Macrocyclic bis(ureas as ligands for anion complexation

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Claudia Kretschmer

2014-08-01

Full Text Available Two macrocyclic bis(ureas 1 and 2, both based on diphenylurea, have been synthesized. Compound 1 represents the smaller ring with two ethynylene groups as linkers and 2 the larger ring with two butadiynylene groups. On thermal treatment to 130 °C molecule 1 splits up into two dihydroindoloquinolinone (3 molecules. Both compounds 1 and 2 form adducts with polar molecules such as dimethyl sulfoxide (DMSO and dimethylformamide (DMF and act as complexing agents towards a series of anions (Cl−, Br−, I−, NO3−, HSO4−. The crystal structures of 3, 2·2DMSO, 2·2DMF, and of the complex NEt4[Br·2] have been determined. Quantitative investigations of the complexation equilibria were performed via 1H NMR titrations. While 1 is a rather weak complexing agent, the large ring of 2 binds anions with association constants up to log K = 7.93 for chloride ions.

Bone bruise in acute traumatic patellar dislocation: volumetric magnetic resonance imaging analysis with follow-up mean of 12 months

International Nuclear Information System (INIS)

Paakkala, Antti; Paakkala, Timo; Sillanpaeae, Petri; Maeenpaeae, Heikki; Huhtala, Heini

2010-01-01

The aim of the study was to assess volumetric analysis of bone bruises in acute primary traumatic patellar dislocation by magnetic resonance imaging (MRI) and resolving resolution of bruises in follow-up MRI. MRI was performed in 23 cases. A follow-up examination was done at a mean of 12 months after dislocation. Volumes of patellar and femur bruises for every patient were evaluated separately by two musculoskeletal radiologists, and mean values of the bruises were assessed. Other MRI findings were evaluated, together with agreement by consensus. Bone bruise volumes were compared with other MR findings. In the acute study 100% of patients showed bruising of the lateral femoral condyle and 96% bruising of the patella. The bruise was located at the medial femoral condyle in 30% and at the patellar median ridge in 74% of patients. The median volume of the femoral bruise was 25,831 mm 3 and of the patellar bruise 2,832 mm 3 . At the follow-up study 22% of patients showed bruising of the lateral femoral condyle and 39% bruising of the patella, the median volumes of the bruises being 5,062 mm 3 and 1,380 mm 3 , respectively. Larger patellar bruise volume correlated with larger femur bruise volume in the acute (r=0.389, P=0.074) and the follow-up (r=1.000, P<0.01) studies. Other MRI findings did not correlate significantly with bone bruise volumes. Bone bruising is the commonest finding in cases of acute patellar dislocation, being seen even 1 year after trauma and indicating significant bone trabecular injury in the patellofemoral joint. A large bruise volume may be associated with subsequent chondral lesion progression at the patella. We concluded that the measurement of bone bruise volume in patients with acute patellar dislocation is a reproducible method but requires further studies to evaluate its clinical use. (orig.)

Physiological and molecular ontogeny of branchial and extra-branchial urea excretion in posthatch rainbow trout (Oncorhynchus mykiss).

Science.gov (United States)

Zimmer, Alex M; Wood, Chris M

2016-02-01

All teleost fish produce ammonia as a metabolic waste product. In embryos, ammonia excretion is limited by the chorion, and fish must detoxify ammonia by synthesizing urea via the ornithine urea cycle (OUC). Although urea is produced by embryos and larvae, urea excretion (J(urea)) is typically low until yolk sac absorption, increasing thereafter. The aim of this study was to determine the physiological and molecular characteristics of J(urea) by posthatch rainbow trout (Oncorhynchus mykiss). Following hatch, whole body urea concentration decreased over time, while J(urea) increased following yolk sac absorption. From 12 to 40 days posthatch (dph), extra-branchial routes of excretion accounted for the majority of J(urea), while the gills became the dominant site for J(urea) only after 55 dph. This represents the most delayed branchial ontogeny of any process studied to date. Urea transporter (UT) gene expression in the gills and skin increased over development, consistent with increases in branchial and extra-branchial J(urea). Following exposure to 25 mmol/l urea, the accumulation and subsequent elimination of exogenous urea was much greater at 55 dph than 12 dph, consistent with increased UT expression. Notably, UT gene expression in the gills of 55 dph larvae increased in response to high urea. In summary, there is a clear increase in urea transport capacity over posthatch development, despite a decrease in OUC activity. Copyright © 2016 the American Physiological Society.

A simple apparatus for measuring the blood urea, manufactured by Dr. Luigj Benusi in 1943 in Albania.

Science.gov (United States)

Tartari, Flamur; Buzo, Stiliano; Vyshka, Gentian

2009-01-01

The apparatus invented by Dr. Luigj Benusi in 1943, in Tirana, was a practical application of the Kowarsky technique and Ambard laws, helping in determining blood urea levels and very important to a variety of diseases, mainly kidney disorders. The apparatus was invented and prepared from very simple laboratory materials, such as glasses, test tubes, corks and volumetric cylinders. Technologically, it was based upon the determination of blood urea through hypobromite, and, among the advantages of the apparatus of Benusi, were its extreme simplicity, the smaller amount of blood needed for producing results (2 milliliters), as well as an easiest way to clean up and to manage the apparatus from a practical point of everyday use.

UREA BREATH TEST – ITS ROLE IN DIAGNOSTICS

Directory of Open Access Journals (Sweden)

Joško Osredkar

2004-01-01

Full Text Available Background. Each year many patients visit their physicians complaining of digestive symptoms, most commonly functional dyspepsia (»indigestion« or gastroesophageal reflux (»heartburn«. However, many patients with abdominal discomfort are actually suffering from gastric or duodenal ulcers that are commonly caused by H. pylori and thus are curable. Clearing the infection usually heals the ulcer and prevents relapse, so an accurate diagnosis is important. There are several options for diagnosing H. pylori infection: serology to detect antibodies against the bacterium; endoscopic biopsy for urease testing (H. pylori produce a urease that breaks down urea to ammonia and carbon dioxide; histology with special stains; or culture. Unfortunately, these procedures are invasive, expensive and not always accurate. Serological tests require a blood sample and tell only that a patient has been exposed to H. pylori at some time in the past, but not whether the patient is currently infected. Endoscopy and biopsy can detect current infection — the CLO test urease test allows rapid detection of H. pylori in gastric biopsy specimens — but endoscopy and biopsy are unpleasant medical procedures.Recently, noninvasive, sensitive, specific, easy to perform and patient’s well accepted methods had been developed known as urea breath test (UBT. When an infected person swallows a dose of urea labeled with an isotope of carbon — carbon-13 (13C or carbon-14 (14C – H. pylori in the gastric mucosa break down the labeled urea to form ammonia and labeled carbon dioxide. The carbon dioxide is absorbed into the bloodstream and excreted via the lungs. The patient then exhales into a device that measures the level of carbon dioxide. The urea breath test is specific for H. pylori (it detects only urease-producing bacteria, it is sensitive (the labeled urea reaches a large area of the stomach and thus reflects total gastric urease activity and the results can be

Can salivary creatinine and urea levels be used to diagnose chronic kidney disease in children as accurately as serum creatinine and urea levels? A case-control study.

Science.gov (United States)

Renda, Rahime

2017-11-01

Children with chronic kidney disease (CKD) develop many metabolic changes in blood that often necessitate frequent biochemical analysis. Serum analysis is an invasive and painful procedure. It would be highly beneficial if a noninvasive alternative process to serum analysis in children were identified. Saliva can be collected noninvasively, repeatedly, and without the use of healthcare personnel. The aims of this study were to compare serum and salivary urea and creatinine levels in children with CKD and healthy controls, and to determine if salivary creatinine and urea levels can be used to diagnose CKD in children as accurately as serum creatinine and urea levels. This case-control study included 35 children with CKD and 28 healthy children as controls. Saliva and blood samples were collected for measurement of urea and creatinine levels. The urea and creatinine levels in serum and saliva in the CKD and control groups were compared using the independent samples Mann-Whitney U test. Correlations between the serum and salivary urea and creatinine levels were determined using Pearson's correlation coefficient. Receiver operating characteristic analysis was used to assess the diagnostic performance of salivary creatinine and cutoff values were identified. In the CKD group, the mean salivary creatinine level was 0.45 mg/dL and the mean salivary urea level was 0.11 mg/dL, versus 28.83 mg/dL and 21.78 mg/dL, respectively, in the control group. Stage 4 and 5 CKD patients had a mean salivary urea level of 31.35 mg/dL, as compared to 17.78 mg/dL in the control group. Serum urea and creatinine, and salivary creatinine were significantly higher in the CKD patients (regardless of disease stage) than in the controls (p creatinine. The area under the curve for salivary creatinine was 0.805. The cutoff value for salivary creatinine was 0.125 mg/dL, with a sensitivity of 82.9% and specificity of 78.6%. Based on the positive correlation between the serum and saliva

[Degradation of urea and ethyl carbamate in Chinese Rice wine by recombinant acid urease].

Science.gov (United States)

Zhou, Jianli; Kang, Zhen; Liu, Qingtao; Du, Guocheng; Chen, Jian

2016-01-01

Ethyl carbamate (EC) as a potential carcinogen commonly exists in traditional fermented foods. It is important eliminate urea that is the precursors of EC in many fermented foods, including Chinese Rice wine. On the basis of achieving high-level overexpression of food-grade ethanol-resistant acid urease, we studied the hydrolysis of urea and EC with the recombinant acid urease. Recombinant acid urease showed degraded urea in both the simulated system with ethanol and Chinese Rice wine (60 mg/L of urea was completely degraded within 25 h), indicating that the recombinant enzyme is suitable for the elimination of urea in Chinese Rice wine. Although recombinant acid urease also has degradation catalytic activity on EC, no obvious degradation of EC was observed. Further investigation results showed that the Km value for urea and EC of the recombinant acid urease was 0.7147 mmol/L and 41.32 mmol/L, respectively. The results provided theoretical foundation for realizing simultaneous degradation of urea and EC.

The microcapsule-type formaldehyde scavenger: the preparation and the application in urea-formaldehyde adhesives.

Science.gov (United States)

Duan, Hongyun; Qiu, Teng; Guo, Longhai; Ye, Jun; Li, Xiaoyu

2015-08-15

The limitation and regulation of formaldehyde emissions (FE) now shows great importance in wood-based materials such as plywood and particle board manufactured for building and furnishing materials. The widely used formaldehyde-based adhesives are one of the main sources of FE from the wood products. In this work, a new kind of long-term effective formaldehyde scavenger in the microcapsule form was prepared by using an intra-liquid desiccation method. The characterizations of the capsule (UC) were performed including the morphologies, the yields, the loading efficiency as well as its sustained-release of urea in aqueous conditions. The prepared UC could be integrated in urea-formaldehyde resins by simply physical blending, and the mixtures were available to be applied as the adhesives for the manufacture of plywood. The bonding strength (BS) and the FE of the bonded plywood in both short (3h) and long (12 week) period were evaluated in detail. It was found that the FE profile of the plywood behaved following a duple exponential law within 12 week. The addition of UC in the adhesive can effectively depress the FE of the plywood not only in a short period after preparation but also in a long-term period during its practical application. The slow released urea would continuously suppress the emission of toxic formaldehyde in a sustained manner without obviously deteriorating on the BS of the adhesives. Copyright © 2015 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2012-01-01

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

Headache and neuropsychic disorders in the puerperium: a case report with suspected deficiency of urea cycle enzymes.

Science.gov (United States)

Tonini, Maria Clara; Bignamini, V; Mattioli, M

2011-05-01

An enzymatic abnormality of the urea cycle is a metabolic disorder occasionally seen in adults, but particularly in the puerperium. The main risk is acute hyperammoniemic encephalopathy, leading to psychosis, coma and even death if not diagnosed promptly and treated appropriately. Headache is frequent in the puerperium normally manifesting between 3 and 6 days after delivery. We describe here a 39-year-old woman, who 3 days after delivery presented diffuse tension-type headache and depression, followed by behavioral disorders, psychomotor agitation, epileptic seizures, and finally coma 2 days later. Pregnancy and normal delivery: routine blood chemistry findings, CT scan, MR imaging, angio-MR of the brain, and lumbar puncture were normal. EEG when seizures started, it showed diffuse slowing, as in the case of metabolic encephalopathy. This led us to assay blood ammonia, which was high at >400 mmol. Liver function and abdominal US were normal; hence, we suspected a urea cycle enzymatic abnormality, and requested for genetic tests. These confirmed a congenital primary metabolic deficiency of arginine succinate synthetase, with high citrullinemia (type II, adult form). Dialysis was started promptly, with initially iv arginine, then orally, plus medical therapy for the hyperammoniemia and a low protein diet; plasma ammonia dropped swiftly to normal, and her state of consciousness gradually improved until all the clinical symptoms had resolved. Ammonia assay should always be considered in the first few days of the puerperium in women with headache and behavioral disorders, to exclude an inborn deficiency of the urea cycle, which may have gone unnoticed until then.

Utilization of residual nitrogen (15N) from cover crop and urea by corn

International Nuclear Information System (INIS)

Silva, Edson Cabral da; Muraoka, Takashi; Trivelin, Paulo Cesar Ocheuze; Buzetti, Salatier; Veloso, Marcos Emanuel da Costa

2006-01-01

The majority of N from mineral fertilizers and cover crops is usually not used by the very next corn crop, but can be absorbed by follow-up crops. The objective of this study was to evaluate the use of residual nitrogen from urea, sunnhemp (Crotalaria juncea) and millet (Pennisetum americanum) labeled with 15 N, applied to no-tillage corn in the previous growing season, in a Red Latosol of the Cerrado. The study was conducted in an experimental farm of the Sao Paulo State University (UNESP), Ilha Solteira, in Selviria county (MS), Brazil, in different areas. The experiment had a randomized complete block design, with 15 treatments and four replications. Treatments were applied to corn crop in the 2001/02 and 2003/04 growing seasons. They were distributed in a 3 x 5 factorial layout, representing the combination of three cover crops: sunnhemp, millet and spontaneous vegetation (fallow) and five N rates (as urea): 0, 30, 80, 130, and 180 kg ha-1 of N. After corn harvest, the two areas were followed in the dry season and were followed by corn crop in the 2002/03 (experiment 1) and 2003/04 (experiment 2) growing seasons, using the same fertilizer rate on all plots to distinguish the residual effect of N sources. The average use of residual N from the millet and sunnhemp residues (above-ground part) by corn crop was less than 3.5 and 3 %, respectively, of the initial amount. The corn uptake of residual N from urea increased in a quadratic manner in experiment 1 and linearly in experiment Two as a response to the applied N rates, and the recover was below 3 %. The cover crop type did not affect the use of residual N of urea by corn, and vice-versa. (author)

77 FR 64464 - Solid Urea From the Russian Federation: Antidumping Duty Administrative Review; 2010-2011

Science.gov (United States)

2012-10-22

... DEPARTMENT OF COMMERCE International Trade Administration [A-821-801] Solid Urea From the Russian... published the preliminary results of the administrative review of the antidumping duty order on solid urea... the administrative review of the antidumping duty order on solid urea from Russia. See Solid Urea From...

Relations between 15N excretion in feces after oral intake of 15N-urea and urea concentration in the blood dependent on the crude fiber intake of pigs

International Nuclear Information System (INIS)

Bergner, H.; Tegtmeier, B.

1985-01-01

9 pigs (33 kg live weight at the beginning of the experiment) received in 3 consecutive series of experiments (3 animals/group) a basic barley ration of 1.0 - 1.2 kg per animal and day. In groups 1 to 9 the following supplements were given: (1) without N supplement, (2) 10.5 g urea, (3) 79 g dried skim milk, (4) 11 g urea, (5) without N supplement, (6) 110 g horse bean coarse meal, (7) without N supplement, (8) 95 g dried skim milk, (9) 120 g horse bean coarse meal. In groups 1 - 6 rations were supplemented with 150 - 165 g dry matter of partly hydrolyzed straw meal per animal and day. After 20 days the animals received a single dosis of 0.5 g/kg/sup 0.75/ 15 N-urea (72.1 atom-% 15 N excess) with the morning meal of the first day of the experiment. During the four days of the experiment groups 1 - 6, due to the straw meal supplement, excreted significantly higher N amounts than the corresponding groups 7 - 9. In comparison with the first day of the experiment (1 h after the morning meal) the urea concentration in the blood decreased to the following percentage in the order of the groups 1 - 9: 64; 65; 77; 54; 64; 73; 82; 88; 84 on the second day of the experiment (1 h before the evening meal). Between the excretion of 15 N excess in feces (y = mg) during the four days of the experiment and the concentration of urea in the blood (x = mmol/l) there was the following significant negative correlation: y = -40.1 x + 340. Urea elimination by means of urea inflow into the large intestine and subsequent bacterial protein synthesis (in the presence of fermentable crude fiber) significantly decreased urea concentration in the blood. (author)

Modeling and measurement of boiling point elevation during water vaporization from aqueous urea for SCR applications

International Nuclear Information System (INIS)

Dan, Ho Jin; Lee, Joon Sik

2016-01-01

Understanding of water vaporization is the first step to anticipate the conversion process of urea into ammonia in the exhaust stream. As aqueous urea is a mixture and the urea in the mixture acts as a non-volatile solute, its colligative properties should be considered during water vaporization. The elevation of boiling point for urea water solution is measured with respect to urea mole fraction. With the boiling-point elevation relation, a model for water vaporization is proposed underlining the correction of the heat of vaporization of water in the urea water mixture due to the enthalpy of urea dissolution in water. The model is verified by the experiments of water vaporization as well. Finally, the water vaporization model is applied to the water vaporization of aqueous urea droplets. It is shown that urea decomposition can begin before water evaporation finishes due to the boiling-point elevation

Modeling and measurement of boiling point elevation during water vaporization from aqueous urea for SCR applications

Energy Technology Data Exchange (ETDEWEB)

Dan, Ho Jin; Lee, Joon Sik [Seoul National University, Seoul (Korea, Republic of)

2016-03-15

Understanding of water vaporization is the first step to anticipate the conversion process of urea into ammonia in the exhaust stream. As aqueous urea is a mixture and the urea in the mixture acts as a non-volatile solute, its colligative properties should be considered during water vaporization. The elevation of boiling point for urea water solution is measured with respect to urea mole fraction. With the boiling-point elevation relation, a model for water vaporization is proposed underlining the correction of the heat of vaporization of water in the urea water mixture due to the enthalpy of urea dissolution in water. The model is verified by the experiments of water vaporization as well. Finally, the water vaporization model is applied to the water vaporization of aqueous urea droplets. It is shown that urea decomposition can begin before water evaporation finishes due to the boiling-point elevation.

A large response range reflectometric urea biosensor made from silica-gel nanoparticles.

Science.gov (United States)

Alqasaimeh, Muawia; Heng, Lee Yook; Ahmad, Musa; Raj, A S Santhana; Ling, Tan Ling

2014-07-22

A new silica-gel nanospheres (SiO2NPs) composition was formulated, followed by biochemical surface functionalization to examine its potential in urea biosensor development. The SiO2NPs were basically synthesized based on sol-gel chemistry using a modified Stober method. The SiO2NPs surfaces were modified with amine (-NH2) functional groups for urease immobilization in the presence of glutaric acid (GA) cross-linker. The chromoionophore pH-sensitive dye ETH 5294 was physically adsorbed on the functionalized SiO2NPs as pH transducer. The immobilized urease determined urea concentration reflectometrically based on the colour change of the immobilized chromoionophore as a result of the enzymatic hydrolysis of urea. The pH changes on the biosensor due to the catalytic enzyme reaction of immobilized urease were found to correlate with the urea concentrations over a linear response range of 50-500 mM (R2 = 0.96) with a detection limit of 10 mM urea. The biosensor response time was 9 min with reproducibility of less than 10% relative standard deviation (RSD). This optical urea biosensor did not show interferences by Na+, K+, Mg2+ and NH4+ ions. The biosensor performance has been validated using urine samples in comparison with a non-enzymatic method based on the use of p-dimethylaminobenzaldehyde (DMAB) reagent and demonstrated a good correlation between the two different methods (R2 = 0.996 and regression slope of 1.0307). The SiO2NPs-based reflectometric urea biosensor showed improved dynamic linear response range when compared to other nanoparticle-based optical urea biosensors.

A Large Response Range Reflectometric Urea Biosensor Made from Silica-Gel Nanoparticles

Science.gov (United States)

Alqasaimeh, Muawia; Heng, Lee Yook; Ahmad, Musa; Raj, A.S. Santhana; Ling, Tan Ling

2014-01-01

A new silica-gel nanospheres (SiO2NPs) composition was formulated, followed by biochemical surface functionalization to examine its potential in urea biosensor development. The SiO2NPs were basically synthesized based on sol–gel chemistry using a modified Stober method. The SiO2NPs surfaces were modified with amine (-NH2) functional groups for urease immobilization in the presence of glutaric acid (GA) cross-linker. The chromoionophore pH-sensitive dye ETH 5294 was physically adsorbed on the functionalized SiO2NPs as pH transducer. The immobilized urease determined urea concentration reflectometrically based on the colour change of the immobilized chromoionophore as a result of the enzymatic hydrolysis of urea. The pH changes on the biosensor due to the catalytic enzyme reaction of immobilized urease were found to correlate with the urea concentrations over a linear response range of 50–500 mM (R2 = 0.96) with a detection limit of 10 mM urea. The biosensor response time was 9 min with reproducibility of less than 10% relative standard deviation (RSD). This optical urea biosensor did not show interferences by Na+, K+, Mg2+ and NH4+ ions. The biosensor performance has been validated using urine samples in comparison with a non-enzymatic method based on the use of p-dimethylaminobenzaldehyde (DMAB) reagent and demonstrated a good correlation between the two different methods (R2 = 0.996 and regression slope of 1.0307). The SiO2NPs-based reflectometric urea biosensor showed improved dynamic linear response range when compared to other nanoparticle-based optical urea biosensors. PMID:25054632

Acid-Urea Gel Electrophoresis and Western Blotting of Histones.

Science.gov (United States)

Hazzalin, Catherine A; Mahadevan, Louis C

2017-01-01

Acid-urea gel electrophoresis offers significant advantages over SDS-PAGE for analysis of post-translational protein modifications, being capable of resolving proteins of similar size but varying in charge. Hence, it can be used to separate protein variants with small charge-altering differences in primary sequence, and is particularly useful in the analysis of histones whose charge variation arises from post-translational modification, such as phosphorylation or acetylation. On acid-urea gels, histones that carry multiple modifications, each with a characteristic charge, are resolved into distinct bands, the so-called "histone ladder." Thus, the extent and distribution of different modification states of histones can be visualized. Here, we describe the analysis of histone H3 by acid-urea gel electrophoresis and western blotting.

Modulation of cadmium-induced phytotoxicity in Cabomba caroliniana by urea involves photosynthetic metabolism and antioxidant status.

Science.gov (United States)

Huang, Wenmin; Shao, Hui; Zhou, Sining; Zhou, Qin; Li, Wei; Xing, Wei

2017-10-01

Urea is a widespread organic pollutant, which can be a nitrogen source, playing different roles in the growth of submerged macrophytes depending on concentrations, while high cadmium (Cd) concentrations are often toxic to macrophytes. In order to evaluate the combined effect of urea and Cd on a submerged macrophyte, Cabomba caroliniana, the morphological and physiological responses of C. caroliniana in the presence of urea and Cd were studied. The results showed that high concentrations of urea (400mgL -1 ) and Cd (500µmolL -1 ) had negative effects on C. caroliniana. There were strong visible symptoms of toxicity after 4 days of exposure under Cd-alone, 400mgL -1 urea, and Cd+400mgL -1 urea treatments. In addition, 400mgL -1 urea and Cd had adverse effects on C. caroliniana's pigment system. Significant losses in chlorophyll fluorescence and photosynthetic rates, as well as Rubisco activity were also observed under Cd-alone, 400mgL -1 urea, and Cd+400mgL -1 urea treatments. 400mgL -1 urea markedly enhanced Cd toxicity in C. caroliniana, reflected by a sharp decrease in photosynthetic activity and more visible toxicity symptoms. The results of thiobarbituric acid reactive substances (TBARS) pointed to extreme oxidative stress in C. caroliniana induced under Cd or 400mgL -1 urea exposure. Exogenous ascorbate (AsA) protected C. caroliniana from adverse damage in 400mgL -1 urea, which further corroborated the oxidative stress claim under 400mgL -1 urea. However, results also demonstrated that lower urea concentration (10mgL -1 ) alleviated Cd-induced phytotoxicity by stimulating chlorophyll synthesis and photosynthetic activity, as well as activating the activity of catalase (CAT) and glutathione-S-transferase (GST), which may explain the alleviating effect of urea on C. caroliniana under Cd stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Factors Associated With Follow-Up Attendance Among Rape Victims Seen in Acute Medical Care.

Science.gov (United States)

Darnell, Doyanne; Peterson, Roselyn; Berliner, Lucy; Stewart, Terri; Russo, Joan; Whiteside, Lauren; Zatzick, Douglas

2015-01-01

Rape is associated with posttraumatic stress disorder (PTSD) and related comorbidities. Most victims do not obtain treatment for these conditions. Acute care medical settings are well positioned to link patients to services; however, difficulty engaging victims and low attendance at provided follow-up appointments is well documented. Identifying factors associated with follow-up can inform engagement and linkage strategies. Administrative, patient self-report, and provider observational data from Harborview Medical Center were combined for the analysis. Using logistic regression, we examined factors associated with follow-up health service utilization after seeking services for rape in the emergency department. Of the 521 diverse female (n = 476) and male (n = 45) rape victims, 28% attended the recommended medical/counseling follow-up appointment. In the final (adjusted) logistic regression model, having a developmental or other disability (OR = 0.40, 95% CI = 0.21-0.77), having a current mental illness (OR = 0.25, 95% CI = 0.13-0.49), and being assaulted in public (OR = 0.50, 95% CI = 0.28-0.87) were uniquely associated with reduced odds of attending the follow-up. Having a prior mental health condition (OR = 3.02, 95% CI = 1.86-4.91), a completed Sexual Assault Nurse Examiner's (SANE) examination (OR = 2.97, 95% CI = 1.84-4.81), and social support available to help cope with the assault (OR = 3.54, 95% CI = 1.76-7.11) were associated with an increased odds of attending the follow-up. Findings point to relevant characteristics ascertained at the acute care medical visit for rape that may be used to identify victims less likely to obtain posttraumatic medical and mental health services. Efforts to improve service linkage for these patients is warranted and may require alternative service delivery models that engage rape survivors and support posttraumatic recovery.

Salivary creatinine and urea analysis in patients with chronic kidney disease: a case control study.

Science.gov (United States)

Lasisi, Taye Jemilat; Raji, Yemi Raheem; Salako, Babatunde Lawal

2016-01-16

Many metabolic changes develop in patients with chronic kidney disease which often necessitate frequent biochemical analysis of blood. Saliva analysis as an alternative to blood has many advantages. The aims of this study were to evaluate levels of salivary creatinine and urea in patients with chronic kidney disease in comparison to healthy individuals; to determine correlation between salivary creatinine/urea and blood creatinine/urea and to evaluate the diagnostic potential of saliva. A case control study, involving 50 patients with late stage chronic kidney disease and 49 healthy individuals as control. Blood and saliva samples were analyzed for urea and creatinine levels. Data are presented as median with interquartile range and compared using Independent Samples Mann Whitney U test. Correlation between plasma and salivary creatinine as well as urea was determined using Spearman's correlation test. Receiver operating characteristics (ROC) analysis was done to determine the diagnostic ability of salivary creatinine and urea and cut-off values were established. Median salivary creatinine levels were 2.60 mg/dl and 0.20 mg/dl while median salivary urea levels were 92.00 mg/dl and 20.50 mg/dl in patients with chronic kidney disease and controls respectively. Salivary levels of creatinine and urea were significantly elevated in chronic kidney disease patients (p creatinine as well as urea levels. Total areas under the curve for salivary creatinine and urea were 0.97 and 0.89 respectively. Cut-off values for salivary creatinine and urea were 0.55 mg/dl and 27.50 mg/dl respectively which gave sensitivity and specificity of 94 % and 85 % for creatinine; as well as 86 % and 93 % for urea. Findings of this study suggest that analysis of salivary creatinine and urea in patients with chronic kidney disease reflects their levels in blood. Hence, salivary creatinine and urea could be used as diagnostic biomarkers of chronic kidney disease.

1,1′-Binaphthyl-2,2′-dicarboxylic acid–urea (1/1

Directory of Open Access Journals (Sweden)

Edwin Weber

2008-10-01

Full Text Available In the title co-crystal, C22H14O4·CH4N2O, the 1,1′-binaphthyl-2,2′-dicarboxylic acid (BNDA and urea molecules are connected via a system of hydrogen bonds into a chiral two-dimensional polymeric structure parallel to the (001 plane. As the crystal is centrosymmetric, it consists of alternately stacked BNDA–urea layers of opposite chirality. The urea H atoms trans to the C=O group are bonded in a chelating mode [R12(6] to the carbonyl O atom from one of the carboxylic acid groups which, in turn, acts as the donor of an O—H...O hydrogen bond to another urea molecule. The [010] chains thus formed are further connected via an R22(8 hydrogen-bond motif formed between urea and the second carboxylic acid group of BNDA.

Stable isotope 15N-urea and clinical research in nephrology

International Nuclear Information System (INIS)

Sugino, Nobuhiro; Arai, Junko; Akimoto, Mitsuko; Miwa, Toichiro; Takuma, Takehide

1990-01-01

Stable isotope 15 N-compound, 15 N-urea, is useful marker to investigate nitrogen metabolism in clinical nephrology, particularly in chronic renal failure or dialysis. 15 N-urea incorporation into plasma albumin in addition to plasma 15 N disappearance was studied in 6 patients with endstage chronic renal failure. As a result, only minor fraction of administered 15 N-urea was incorporated into albumin in this study. In addition, it was also confirmed that high energy diet may promote protein synthesis through 15 N incorporation to plasma amino acids, such as alanine, in these patients with low protein meal. Therefore, administration of 15 N-compound to human subjects may contribute to provide us the important informations on nitrogen metabolism. For instance, urea kinetics are described in the endstage chronic renal failure in this review. However, less expensive 15 N-compounds should be provided and more simple but accurate measurement of 15 N activity should be developed for the further clinical application of the stable isotope. (author)

Contrasting Features of Urea Cycle Disorders in Human Patients and Knockout Mouse Models

OpenAIRE

Deignan, Joshua L.; Cederbaum, Stephen D.; Grody, Wayne W.

2007-01-01

The urea cycle exists for the removal of excess nitrogen from the body. Six separate enzymes comprise the urea cycle, and a deficiency in any one of them causes a urea cycle disorder (UCD) in humans. Arginase is the only urea cycle enzyme with an alternate isoform, though no known human disorder currently exists due to a deficiency in the second isoform. While all of the UCDs usually present with hyperammonemia in the first few days to months of life, most disorders are distinguished by a cha...

Identification of two evolutionarily conserved 5' cis-elements involved in regulating spatiotemporal expression of Nolz-1 during mouse embryogenesis.

Directory of Open Access Journals (Sweden)

Sunny Li-Yun Chang

Full Text Available Proper development of vertebrate embryos depends not only on the crucial funtions of key evolutionarily conserved transcriptional regulators, but also on the precisely spatiotemporal expression of these transcriptional regulators. The mouse Nolz-1/Znf503/Zfp503 gene is a mammalian member of the conserved zinc-finger containing NET family. The expression pattern of Nolz-1 in mouse embryos is highly correlated with that of its homologues in different species. To study the spatiotemporal regulation of Nolz-1, we first identified two evolutionarily conserved cis-elements, UREA and UREB, in 5' upstream regions of mouse Nolz-1 locus. We then generated UREA-LacZ and UREB-LacZ transgenic reporter mice to characterize the putative enhancer activity of UREA and UREB. The results indicated that both UREA and UREB contained tissue-specific enhancer activity for directing LacZ expression in selective tissue organs during mouse embryogensis. UREA directed LacZ expression preferentially in selective regions of developing central nervous system, including the forebrain, hindbrain and spinal cord, whereas UREB directed LacZ expression mainly in other developing tissue organs such as the Nolz-1 expressing branchial arches and its derivatives, the apical ectodermal ridge of limb buds and the urogenital tissues. Both UREA and UREB directed strong LacZ expression in the lateral plate mesoderm where endogenous Nolz-1 was also expressed. Despite that the LacZ expression pattern did not full recapitulated the endogenous Nolz-1 expression and some mismatched expression patterns were observed, co-expression of LacZ and Nolz-1 did occur in many cells of selective tissue organs, such as in the ventrolateral cortex and ventral spinal cord of UREA-LacZ embryos, and the urogenital tubes of UREB-LacZ embryos. Taken together, our study suggests that UREA and UREB may function as evolutionarily conserved cis-regulatory elements that coordinate with other cis-elements to regulate

HDAC up-regulation in early colon field carcinogenesis is involved in cell tumorigenicity through regulation of chromatin structure.

Directory of Open Access Journals (Sweden)

Yolanda Stypula-Cyrus

Full Text Available Normal cell function is dependent on the proper maintenance of chromatin structure. Regulation of chromatin structure is controlled by histone modifications that directly influence chromatin architecture and genome function. Specifically, the histone deacetylase (HDAC family of proteins modulate chromatin compaction and are commonly dysregulated in many tumors, including colorectal cancer (CRC. However, the role of HDAC proteins in early colorectal carcinogenesis has not been previously reported. We found HDAC1, HDAC2, HDAC3, HDAC5, and HDAC7 all to be up-regulated in the field of human CRC. Furthermore, we observed that HDAC2 up-regulation is one of the earliest events in CRC carcinogenesis and observed this in human field carcinogenesis, the azoxymethane-treated rat model, and in more aggressive colon cancer cell lines. The universality of HDAC2 up-regulation suggests that HDAC2 up-regulation is a novel and important early event in CRC, which may serve as a biomarker. HDAC inhibitors (HDACIs interfere with tumorigenic HDAC activity; however, the precise mechanisms involved in this process remain to be elucidated. We confirmed that HDAC inhibition by valproic acid (VPA targeted the more aggressive cell line. Using nuclease digestion assays and transmission electron microscopy imaging, we observed that VPA treatment induced greater changes in chromatin structure in the more aggressive cell line. Furthermore, we used the novel imaging technique partial wave spectroscopy (PWS to quantify nanoscale alterations in chromatin. We noted that the PWS results are consistent with the biological assays, indicating a greater effect of VPA treatment in the more aggressive cell type. Together, these results demonstrate the importance of HDAC activity in early carcinogenic events and the unique role of higher-order chromatin structure in determining cell tumorigenicity.

Urea in Weaver Ant Feces: Quantification and Investigation of the Uptake and Translocation of Urea in Coffea Arabica

DEFF Research Database (Denmark)

Vidkjær, Nanna Hjort; Wollenweber, Bernd; Jensen, Karl-Martin Vagn

2016-01-01

Weaver ants are tropical insects that nest in tree canopies, and for centuries these ants have been used for pest control in tropical orchards. Trees hosting weaver ants might benefit not only from the pest protective properties of these insects but also an additional supply of nutrients from ant...... investigate the interactions of weaver ants with the host plants with respect to plant nutrition. Here, we report the identification and quantification of urea, a highly effective foliar nutrient present in the fecal depositions of O. smaragdina. Feces samples obtained from six O. smaragdina colonies were....... The results clearly demonstrated that fecal urea was not only assimilated but also translocated within the plant. This evidence strongly supports the hypothesis that the fecal urea of weaver ants is a source of nitrogen for the host trees. Thus, weaver ant feces likely contribute to an improved nutritional...

DMPD: Mechanism of age-associated up-regulation in macrophage PGE2 synthesis. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 15331118 Mechanism of age-associated up-regulation in macrophage PGE2 synthesis. Wu...e-associated up-regulation in macrophage PGE2 synthesis. PubmedID 15331118 Title Mechanism of age-associated... up-regulation in macrophage PGE2 synthesis. Authors Wu D, Meydani SN. Publicatio

Charge-signal multiplication mediated by urea wires inside Y-shaped carbon nanotubes

International Nuclear Information System (INIS)

Lv, Mei; Liu, Zengrong; He, Bing; Xiu, Peng; Tu, Yusong

2014-01-01

In previous studies, we reported molecular dynamics (MD) simulations showing that single-file water wires confined inside Y-shaped single-walled carbon nanotubes (Y-SWNTs) held strong and robust capability to convert and multiply charge signals [Y. S. Tu, P. Xiu, R. Z. Wan, J. Hu, R. H. Zhou, and H. P. Fang, Proc. Natl. Acad. Sci. U.S.A. 106, 18120 (2009); Y. Tu, H. Lu, Y. Zhang, T. Huynh, and R. Zhou, J. Chem. Phys. 138, 015104 (2013)]. It is fascinating to see whether the signal multiplication can be realized by other kinds of polar molecules with larger dipole moments (which make the experimental realization easier). In this article, we use MD simulations to study the urea-mediated signal conversion and multiplication with Y-SWNTs. We observe that when a Y-SWNT with an external charge of magnitude 1.0 e (the model of a signal at the single-electron level) is solvated in 1 M urea solutions, urea can induce drying of the Y-SWNT and fill its interiors in single-file, forming Y-shaped urea wires. The external charge can effectively control the dipole orientation of the urea wire inside the main channel (i.e., the signal can be readily converted), and this signal can further be multiplied into 2 (or more) output signals by modulating dipole orientations of urea wires in bifurcated branch channels of the Y-SWNT. This remarkable signal transduction capability arises from the strong dipole-induced ordering of urea wires under extreme confinement. We also discuss the advantage of urea as compared with water in the signal multiplication, as well as the robustness and biological implications of our findings. This study provides the possibility for multiplying signals by using urea molecules (or other polar organic molecules) with Y-shaped nanochannels and might also help understand the mechanism behind signal conduction in both physical and biological systems

Unravelling the hydrophobicity of urea in water using thermodiffusion: implications for protein denaturation.

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Niether, Doreen; Di Lecce, Silvia; Bresme, Fernando; Wiegand, Simone

2018-01-03

Urea is widely used as a protein denaturant in aqueous solutions. Experimental and computer simulation studies have shown that it dissolves in water almost ideally at high concentrations, introducing little disruption in the water hydrogen bonded structure. However, at concentrations of the order of 5 M or higher, urea induces denaturation in a wide range of proteins. The origin of this behaviour is not completely understood, but it is believed to stem from a balance between urea-protein and urea-water interactions, with urea becoming possibly hydrophobic at a specific concentration range. The small changes observed in the water structure make it difficult to connect the denaturation effects to the solvation properties. Here we show that the exquisite sensitivity of thermodiffusion to solute-water interactions allows the identification of the onset of hydrophobicity of urea-water mixtures. The hydrophobic behaviour is reflected in a sign reversal of the temperature dependent slope of the Soret coefficient, which is observed, both in experiments and non-equilibrium computer simulations at ∼5 M concentration of urea in water. This concentration regime corresponds to the one where abrupt changes in the denaturation of proteins are commonly observed. We show that the onset of hydrophobicity is intrinsically connected to the urea-water interactions. Our results allow us to identify correlations between the Soret coefficient and the partition coefficient, log P, hence establishing the thermodiffusion technique as a powerful approach to study hydrophobicity.

Papermaking Properties of Carpinus betulus with kraft, Soda and Soda-Urea Pulping Processes

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Rasoul Darstan

2013-06-01

Full Text Available This research was carried out in order to comparatively investigate the hornbeam kraft, soda and soda-urea papermaking properties. The selected treatment in kraft process had an average yield of 44.43% and kappa number of 23.75. In soda process the selected treatment had an average yield of 38.75% and kappa number of 19.28. In soda-urea process, the selected treatments had an average yield of 39.85, 40.1, 40.5, 39.8 and 40.61 and kappa number of 21.21, 22.33, 22.66, 25.28 and 26.85. After refining the selected pulp to reach the freeness of 400±25 ml CSF, 60 g/m2 handsheets were made and physical, mechanical and optical properties were measured. Results showed that kraft pulps had higher yield and better refinability than soda and soda-urea pulps. Papers made from kraft process had higher strength properties than those made of soda and soda-urea process. With addition of urea, yield and kappa number of pulps increased. The highest improvement in tensile index, breaking length and tear index was achieved with addition of 3% urea and the highest improvement in burst index was achieved with adding 4% urea. Results of brightness measurements showed that papers from kraft and soda processes had the lowest and highest brightness degree respectively. With the addition of urea, brightness of papers decreased.

Adsorption of saturated fatty acid in urea complexation: Kinetics and equilibrium studies

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Setyawardhani, Dwi Ardiana; Sulistyo, Hary; Sediawan, Wahyudi Budi; Fahrurrozi, Mohammad

2018-02-01

Urea complexation is fractionation process for concentrating poly-unsaturated fatty acids (PUFAs) from vegetable oil or animal fats. For process design and optimization in commercial industries, it is necessary to provide kinetics and equilibrium data. Urea inclusion compounds (UICs) as the product is a unique complex form which one molecule (guest) is enclosed within another molecule (host). In urea complexation, the guest-host bonding exists between saturated fatty acids (SFAs) and crystalline urea. This research studied the complexation is analogous to an adsorption process. The Batch adsorption process was developed to obtain the experimental data. The ethanolic urea solution was mixed with SFA in certain compositions and adsorption times. The mixture was heated until it formed homogenous and clear solution, then it cooled very slowly until the first numerous crystal appeared. Adsorption times for the kinetic data were determined since the crystal formed. The temperature was maintained constant at room temperature. Experimental sets of data were observed with adsorption kinetics and equilibrium models. High concentration of saturated fatty acid (SFA) was used to represent adsorption kinetics and equilibrium parameters. Kinetic data were examined with pseudo first-order, pseudo second-order and intra particle diffusion models. Linier, Freundlich and Langmuir isotherm were used to study the equilibrium model of this adsorption. The experimental data showed that SFA adsorption in urea crystal followed pseudo second-order model. The compatibility of the data with Langmuir isotherm showed that urea complexation was a monolayer adsorption.

Acute Glomerulonephritis: A 7 Years Follow up of Children in Center of Iran

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Mohsen Akhavan Sepahi

2011-06-01

Full Text Available Acute glomerulonephritis (AGN is a type of renal disease which indicates the inflammation of glomerulus and nephrons. This study was carried on 94 children, <15 years old with the diagnosis of AGN who were admitted to Qom and Yazd's hospitals between 2000 and 2006. Data were collected using hospital records on admission, progression notes and outpatient follow up. Among 94 patients, 55.3% were male and 44.6% were female. Mean age of patients was 8.2±2.7 years old. Acute post streptococcal glomerulonephritis (APSGN was reported in 92.5%, membranoproliferative glomerulonephritis in 4.2%, hemolytic uremic syndrome in 2.1% and IgA nephropathy in 1.06%. There was no significant differences between GN types and gender (P=0.54. Clinical manifestation included edema in 68.8%, oliguria in 36.3%, gross hematuria in 69.1%, HTN in 61.7% and anuria in 1.06%. Microscopic hematuria was detected in all patients. In the time of follow up none of patients had hypertension, 3.1% had proteinuria and 6.3% had microscopic hematuria. APSGN is the most common causes of AGN in Qom and Yazd's children. Early diagnosis and treatment of APSGN may protect children from long term morbidity and mortality and improve quality of life.

Gene expression in Catla catla (Hamilton) subjected to acute and protracted doses of gamma radiation

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Anbumani, S., E-mail: aquatox1982@gmail.com; Mohankumar, Mary N., E-mail: marynmk@gmail.com

2016-09-15

Highlights: • Gamma radiation induced up- and down- regulation of cell cycle genes. • Protracted dose-rate induced gene up-regulation to facilitate cell survival. • bcl-2 gene facilitates repair at protracted dose and cell death at acute exposures. • gadd45α, cdk1 and bcl-2 genes work in concert to promote ‘repair’ and ‘death’ circuitries in fish blood cells. - Abstract: Studies on transcriptional modulation after gamma radiation exposure in fish are limited. Cell cycle perturbations and expression of apoptotic genes were investigated in the fish, Catla catla after acute and protracted exposures to gamma radiation over a 90 day period. Significant changes in gene expression were observed between day 1 and 90 post-exposure. Gamma radiation induced a significant down-regulation of target genes gadd45α, cdk1 and bcl-2 from day 1 to day 3 after protracted exposure, whereas it persists till day 6 upon acute exposure. From day 12 onwards, Gadd45α, cdk1 and bcl-2 genes were up-regulated following protracted exposure, indicating DNA repair, cell-cycle arrest and apoptosis. There exists a linear correlation between these genes (gadd45α – r = 0.85, p = 0.0073; cdk1 – r = 0.86, p = 0.0053; bcl-2 – r = 0.89, p = 0.0026) at protracted exposures. This is the first report on the dual role of bcl-2 gene in fish exposed to acute and protracted radiation and correlation among the aforementioned genes that work in concert to promote ‘repair’ and ‘death’ circuitries in fish blood cells.

Gene expression in Catla catla (Hamilton) subjected to acute and protracted doses of gamma radiation

International Nuclear Information System (INIS)

Anbumani, S.; Mohankumar, Mary N.

2016-01-01

Highlights: • Gamma radiation induced up- and down- regulation of cell cycle genes. • Protracted dose-rate induced gene up-regulation to facilitate cell survival. • bcl-2 gene facilitates repair at protracted dose and cell death at acute exposures. • gadd45α, cdk1 and bcl-2 genes work in concert to promote ‘repair’ and ‘death’ circuitries in fish blood cells. - Abstract: Studies on transcriptional modulation after gamma radiation exposure in fish are limited. Cell cycle perturbations and expression of apoptotic genes were investigated in the fish, Catla catla after acute and protracted exposures to gamma radiation over a 90 day period. Significant changes in gene expression were observed between day 1 and 90 post-exposure. Gamma radiation induced a significant down-regulation of target genes gadd45α, cdk1 and bcl-2 from day 1 to day 3 after protracted exposure, whereas it persists till day 6 upon acute exposure. From day 12 onwards, Gadd45α, cdk1 and bcl-2 genes were up-regulated following protracted exposure, indicating DNA repair, cell-cycle arrest and apoptosis. There exists a linear correlation between these genes (gadd45α – r = 0.85, p = 0.0073; cdk1 – r = 0.86, p = 0.0053; bcl-2 – r = 0.89, p = 0.0026) at protracted exposures. This is the first report on the dual role of bcl-2 gene in fish exposed to acute and protracted radiation and correlation among the aforementioned genes that work in concert to promote ‘repair’ and ‘death’ circuitries in fish blood cells.

Dry season supplementation of dairy cows with urea molasses mineral blocks and molasses-urea mix in the Morogoro region in Tanzania

International Nuclear Information System (INIS)

Plaizier, J.C.B.; McBride, B.W.; Nkya, R.; Shem, M.N.; Urio, N.A.

1999-01-01

The effects of supplementation with urea molasses mineral blocks and molasses-urea mix during and immediately prior to the dry season on the production of dairy cows were studied on-station and on small holder peri-urban farms near Morogoro, Tanzania. Supplementation of on-station cows receiving ad libitum grass hay and 6 kg/d of maize bran with urea molasses mineral blocks (UMMB), increased milk production from 6.7 L/d to 11.2 L/d (P <0.05) and dry matter intake from 10.1 kg/d to 12.0 kg/d (P <0.05), but did not significantly affect milk composition, intake of hay and live weight change. This increase in milk yield is mainly explained by increased intakes of energy and nitrogen. Supplementation with the molasses urea mix increased daily milk yield from 6.7 L/d to 8.8 L/d (P <0.05), but did not significantly affect the other measured production parameters. The on-farm supplementation with blocks increased daily milk yield by 1.7 L/d in the dry season (P <0.01). This supplementation did not increase milk yields prior to the dry season, since quality forage was still available. Taking the production costs into account, supplementation with the blocks and supplementation with molasses mix was cost effective if milk yields increased by 0.7 L/d. (author)

The transport kinetics and selectivity of HpUreI, the urea channel from Helicobacter pylori†

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Gray, Lawrence R; Gu, Sean X; Quick, Matthias; Khademi, Shahram

2017-01-01

Helicobacter pylori’s unique ability to colonize and survive in the acidic environment of the stomach is critically dependent on uptake of urea through the urea channel, HpUreI. Hence, HpUreI may represent a promising target for the development of specific drugs against this human pathogen. To obtain insight into the structure/function relationship of this channel, we have developed conditions for the high-yield expression and purification of stable recombinant HpUreI that allowed its detailed kinetic characterization in solubilized form and reconstituted into liposomes. Detergent-solubilized HpUreI forms homo-trimer, as determined by chemical cross-linking. Urea dissociation kinetics of purified HpUreI were determined by means of the scintillation proximity assay (SPA), whereas urea efflux was measured in HpUreI-containing proteoliposomes using stopped-flow spectrometry to determine the kinetics and selectivity of the urea channel. The kinetic analyses revealed that urea conduction in HpUreI is pH sensitive and saturable with a half-saturation concentration (or K0.5) of ~163 mM. Binding of urea by HpUreI was increased at lower pH; however, the apparent affinity of urea binding (~150 mM) was not significantly pH dependent. The solute selectivity analysis indicated that HpUreI is highly selective for urea and hydroxyurea. Removing either amino group of urea molecules diminishes their permeability through HpUreI. Similar to urea conduction, water diffusion through HpUreI is pH-dependent with low water permeability at neutral pH. PMID:21877689

PRODUCTION OF HIGH DENSITY PARTICLEBOARD USING MELAMINE-UREA-FORMALDEHYDE RESIN

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Setsuo Iwakiri

2005-12-01

Full Text Available This research was developed aiming to evaluate the effects of board density and melamine-urea-formaldehyde resin onthe properties of particleboard for semi-structural applications. The boards were manufactured with nominal density of 0.65 g/cm³and 0.90 g/cm³ using urea-formaldehyde resin as control and melamine-urea-formaldehyde. The results showed a better dimensionallystability and mechanical properties of the boards manufactured with higher density and MUF resin content. The fine furnish usedfor external layer of particleboard in the industrial process, could be used for high density homogeneous board to semi-strucuturaluses, such as flooring applications.

Thermophysical Properties of Fluid Latent Heat Storage Material using Urea-Water Mixture

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Hokamura, Taku; Ohkubo, Hidetoshi; Ashizawa, Kiyonori

This study is concerned with the measurement of thermophysical properties of a urea-water mixture with the aim of adopting the mixture as a latent heat storage material for air-conditioning systems. The urea-water mixture is made of natural substances and has a good fluidity. The urea concentration in the mixture was controlled by measuring the refractive index of the mixture. Being a multi-component substance, a urea-water solution has a liquid-solid co-existent phase on a phase-diagram. Therefore, the liquidus temperature was measured to establish a relationship between the fraction of the solid-phase and temperature. Furthermore, apparent values of specific heat and coefficient of viscosity were measured in the two-phase region where the solid phase is ice. The apparent specific heat and coefficient of viscosity were measure by using an adiabatic calorimeter and a stirring torque meter respectively. The results revealed that the urea-water mixture can probably be used as a latent heat storage material of good fluidity.