Urea reduction ratio

In practice, rather than using full UKM, the simplest calculation is the urea reduction ratio (URR). The percentage fall in plasma urea attained during a dialysis session is measured as follows ... 

Urea reduction ratio (URR) = (predialysis-postdialysis urea/predialysis urea) x 100 should be >60% if dialysis is adequate. 

Owen WF, Lew NL, Liu Y, Lowrie EG, Lazarus JM. The urea reduction ratio and serum albumin concentration as predictors of mortality in patients undergoing hemodialysis. N Engl J Med 1993 329 1001-6. 

Sherman RA, Cody RP, Rogers ME, Soianchick JC. Accuracy of the urea reduction ratio in predicting dialysis delivery. Kidney Int 1995 47 319-21. 

The Kt/Vand urea reduction ratio are the most commonly used indicators for hemodialysis adequacy. The National Kidney Foundation s Kidney Disease Outcomes Quality Initiative has set a goal /Cf/Vof greater than 1.2 and a goal urea reduction ratio of greater than 65%. 

The desired dose of dialysis in terms of solute removal can be expressed as a urea reduction ratio (URR) or the Kt/V (pronounced K-T-over-V ). The URR is calculated as ... 

ISPD International Society of Peritoneal Dialysis MRSA methicillin-resistant Staphylococcus aureus MRSE methicillin-resistant enterococcus NKF-K/DOQl National Kidney Foundation Kidney Disease Outcomes Quahtative Initiative PAN polyacrylonitrile PMMA polymethylmethacrylate PS polysulfone URR urea reduction ratio USRDS United States Renal Data System VRE vancomycin-resistant enterococcus WBC white blood cell (count)... 

The term access surveillance refers to device-based measurements (such as VA pressures and blood flow) that have been developed to overcome the limitations of PE. Serial measurements of adequacy parameters (Kt/V or urea reduction ratio -URR) of HD have not proved very useful in detecting stenosis. An acute decrease in Kt/V >0.2 units with AVG has shown a positive predictive value of 69% in detecting significant graft stenosis [13]. Clinical signs of dysfunction such as difficulty in cannulation, aspiration of clots or prolonged needle access site bleeding often prompt... 

Urea Reduction Ratio (URR), which is defined in terms of pie- and post-blood-urea-nitrogen (BUN) values as (Owen et al., 1993) ... 

Reduction in the emission characteristics of unfinished hardwood plywood is currently being achieved primarily by the use of low formaldehyde to urea molar ratio formulations. For the manufacture of hardwood plywood and particleboard, formaldehyde to urea molar ratios have been reduced to a range of 1.15/1 to 1.3/1. An important caveat low F/U ratios perhaps should be considered a proxy for the potential to reduce emissions through improved urea-formaldehyde adhesive technology rather than the exclusive means for improvement. Reducing the F/U ratio is not always the most effective way of reducing emissions in consideration of the variety of hardwood plywood constructions, products, and thicknesses. ... 

A 3.5 h treatment of a 70 kg patient (V = 40.6 liters) with a urea clearance of 200 ml,/min should result in a 64% reduction in urea concentration or a value of 0.36 for the ratio d (f this parameter almost always falls between 0.30 and 0.45. The increase in urea concentration between hemodialysis treatments is obtained from equation 13, again assuming a constant V, where (f is the urea concentration in the patient s blood at the end of the hemodialysis, and d the concentration at time t during the intradialytic interval. 

Azotaemia develops progressively with an increase in creatinine and urea. These findings point to a drop in the glomerular filtration rate (GFR) and renal blood flow. The quotient of creatinine in the urine and plasma is high (>40). Likewise, the quotient of urea-N in the urine and plasma is elevated (> 8). There is a reduction in creatinine clearance within 24 hours to < 40 ml/min. The serum value of urea displays a disproportionate increase compared to creatinine (urea-N/creatinine ratio >20), since the tubular reabsorptive capacity with respect to urea depends on diuresis (maximum 2 ml/ min). In hepatorenal syndrome, the minimal urinary flow gives rise to a longer tubular period of contact with greater tubular reabsorption of urea. 

Partial reduction of SCFs One mg/ml solutions of SCF dimer species were incubated in the presence of 1.24 mg/ml dithiothreitol (DTT) in 0.1 M Tris-HCl buffer (pH 8.5) containing 2.5 M urea, 60 mM NaCl, 2 mM EDTA. Aliquots of the reaction mixture were removed at selected time intervals and unreacted thiols were blocked by the addition of 1 M iodoacetic acid (10 1 molar ratio to the thiol) in 0.3 M Tris, pH 8.0 for 2 min at room temperature. Samples were then quickly frozen in a methanol/dry ice bath and subsequently analyzed by RP-HPLC using conditions described previously (21). 

The reduction of ergoline alkaloid 5 can be performed in the presence of aniline as the proton source. Addition of lithium amide deprotonates the urea side chain. Under these reaction conditions, cleavage of the urea side chain is suppressed and the reduction product 6 is formed in a trims cis ratio of >95 59. 

The ruthenium compounds, Ru35 and Ru3 were -found to promote the homogeneous reduction o-f PhN02 to PhNH2 by CO and H2 in good yields and conversions [318]. At CO/H2 ratio higer than 1, PhNHCONHPh is also a product and its yields increase gradually with the CO/H2 ratio. At 140-160"C, with Pqq=148 atm and =12 atm, without solvent, 54 < o-f the urea has been obtained 318]... 

In the presence of acetic acid, the NaBHa/TMSCl combination is the reagent of choice for reductive amination of urea and aromatic aldehydes. Either the mono-alkylated urea or the di-alkylated urea can be obtained in good yields, depending on the ratio of urea and the aldehyde (eq 72). ... 

A furnace injection process was studied by Himes et al. (1990), They conducted tests using a dry lime-urea hydrate injected into a high-temperature gas stream simulating the upper furnace region of a boiler. The tests demonstrated simultaneous SO2 and NO, reductions of 65% at mole ratios of 3 and 1.5, respectively, for Ca/S and N/NO,. Gullett et al. (1991) report on tests with a slurry of lime in urea-based solution. These tests, which were... 

---