Creatinine


Another example of a separation technique based on size is dialysis, in which a semipermeable membrane is used to separate the analyte and interferent. Dialysis membranes are usually constructed from cellulose, with pore sizes of 1-5 nm. The sample is placed inside a bag or tube constructed from the membrane. The dialysis membrane and sample are then placed in a container filled with a solution whose composition differs from that of the sample. If the concentration of a particular species is not the same on the two sides of the membrane, the resulting concentration gradient provides a driving force for its diffusion across the membrane. Although small particles may freely pass through the membrane, larger particles are unable to pass (Figure 7.11). Dialysis is frequently used to purify proteins, hormones, and enzymes. During kidney dialysis, metabolic waste products, such as urea, uric acid, and creatinine, are removed from blood by passing it over a dialysis membrane.  [c.206]

Representative Method Although each chemical kinetic method has its own unique considerations, the determination of creatinine in urine based on the kinetics of its reaction with picrate provides an instructive example of a typical procedure.  [c.632]

Determination of Creatinine in Urine"  [c.632]

Description of Method. Creatine is an organic acid found in muscle tissue that supplies energy for muscle contractions. One of its metabolic products is creatinine, which is excreted in urine. Because the concentration of creatinine in urine and serum is an important indication of renal function, rapid methods for its analysis are clinically important. In this method the rate of reaction between creatinine and picrate in an alkaline medium is used to determine the concentration of creatinine in urine. Under the conditions of the analysis, the reaction is first-order in picrate, creatinine, and hydroxide.  [c.632]

Rate = /c[picrate][creatinine][OH ]  [c.632]

Since the reaction is carried out under conditions in which it is pseudo-zero-order in creatinine and OH , the rate constant, k, is  [c.633]

This experiment includes instructions for preparing a picrate ion-selective electrode. The application of the electrode in determining the concentration of creatinine in urine (which is further described in Method 13.1) also is outlined.  [c.659]

A marked reduction in the blood urea level of normal individuals implies an improvement in kidney function (see Urea Diuretic agents). Such was observed in a subsequent study (24). Urea and creatinine clearances (clinical measures of kidney function) of six normal college men showed a 25% and 10% improvement, respectively, when they consumed a diet high in bread for seven weeks. This improvement occurred even though the tests at the end of the three-week control period were normal. Throughout the study, the protein level in the diet was maintained constant at 70 g/d. During the control period, the protein came from a mixture of plant and animal sources but during the "bread" period, ca 90% of the dietary protein came from wheat and animal protein was completely excluded. The improvement in kidney function associated with the consumption of a diet high in wheat products suggests a possible therapeutic value for wheat. That might be especially tme for those patients who are starting to manifest aberrations in kidney function which ultimately would require renal dialysis or a kidney transplant.  [c.352]

The American Conference of Governmental Industrial Hygienists (ACGIH) has recommended that time weighted-average exposures for DMF not exceed 10 ppm or 30 mg/m (skin designation, 1989 standard) for an eight-hour work day. In the United States, OSHA has accepted the ACGIH limits ia setting regulations for worker exposures. As with other iadustrial chemicals, regulations and expert opinion evolve over time, and DMF exposure limits may be tightened ia the future. A Biological Exposure Index (BEI) of 40 mg DME metaboUtes /g of creatinine ia urine has also been adopted by ACGIH and apphes ia cases where there is significant potential for absorption of DME is Hquid or vapor through the skin.  [c.515]

Creatinine The most widely used creatinine methods are based on reaction between creatinine and picrate ions formed in an alkaline medium.  [c.39]

Urea (24), amino acids (25), and creatinine (26) are also decomposed during superchlorination or shock treatment, with formation of N2 and other oxidation products. However, the process is slower than with ammonium ion (see Chloramines and BROMAMINEs). Urea is the principal nitrogen-containing compound in swimming pools. Since it is an amide, it reacts slowly with chlorine, yielding N2, NCl, and NO/ (27).  [c.298]

Another example of a separation technique based on size is dialysis, in which a semipermeable membrane is used to separate the analyte and interferent. Dialysis membranes are usually constructed from cellulose, with pore sizes of 1-5 nm. The sample is placed inside a bag or tube constructed from the membrane. The dialysis membrane and sample are then placed in a container filled with a solution whose composition differs from that of the sample. If the concentration of a particular species is not the same on the two sides of the membrane, the resulting concentration gradient provides a driving force for its diffusion across the membrane. Although small particles may freely pass through the membrane, larger particles are unable to pass (Figure 7.11). Dialysis is frequently used to purify proteins, hormones, and enzymes. During kidney dialysis, metabolic waste products, such as urea, uric acid, and creatinine, are removed from blood by passing it over a dialysis membrane.  [c.206]

Representative Method Although each chemical kinetic method has its own unique considerations, the determination of creatinine in urine based on the kinetics of its reaction with picrate provides an instructive example of a typical procedure.  [c.632]

Determination of Creatinine in Urine"  [c.632]

Description of Method. Creatine is an organic acid found in muscle tissue that supplies energy for muscle contractions. One of its metabolic products is creatinine, which is excreted in urine. Because the concentration of creatinine in urine and serum is an important indication of renal function, rapid methods for its analysis are clinically important. In this method the rate of reaction between creatinine and picrate in an alkaline medium is used to determine the concentration of creatinine in urine. Under the conditions of the analysis, the reaction is first-order in picrate, creatinine, and hydroxide.  [c.632]

Rate = /r[picrate][creatinine][OH-]  [c.632]

Since the reaction is carried out under conditions in which it is pseudo-zero-order in creatinine and OH", the rate constant, k, is  [c.633]

Procedure. Prepare a set of external standards containing 0.5 g/L to 3.0 g/L creatinine (in 5 mM H2SO4) using a stock solution of 10.00 g/L creatinine in 5 mM H2SO4. In addition, prepare a solution of 1.00 x 10 M sodium picrate. Pipet 25.00 mL of 0.20 M NaOH, adjusted to an ionic strength of 1.00 M using Na2S04, into a thermostated reaction cell at 25 °C. Add 0.500 mL of the 1.00 x 10 M picrate solution to the reaction cell. Suspend a picrate ion-selective electrode in the solution, and monitor the potential until it stabilizes. When the potential is stable, add 2.00 mL of a  [c.632]

OSHA has set a standard to keep blood levels in the occupational work force below 40 //g/dL. ACGIH has set a goal relating to a biological exposure index of 50 //g/dL for lead in blood and 150 pjgjdL creatinine for lead in urine.  [c.52]

Other Membrane Separation Techniques. The six membrane separation processes described above represent the bulk of the industrial membrane separation industry. A seventh process, dialysis (qv), is used on a large scale to remove toxic metaboUtes from blood in patients suffering from kidney failure (93). The first successful artificial kidney was based on cellophane (regenerated cellulose) membranes and was developed in 1945. Many changes have been made since then. In the 1990s, most artificial kidneys are based on hoUow-fiber modules having a membrane area of about 1 m. Cellulose fibers are stiU widely used, but are gradually being displaced by fibers made from polycarbonate, polysulfone, and other polymers, which have higher fluxes or are less damaging to the blood. As shown in Figure 43, blood is circulated through the center of the fiber, while isotonic saline, the dialysate, is pumped countercurrentiy around the outside of the fibers. Urea, creatinine, and other low molecular weight metaboUtes in the blood diffuse across the fiber wall and are removed with the saline solution. The process is quite slow, usually requiring several hours to remove the required amount of the metabohte from the patient, and must be repeated one to two times per week. Nonetheless, 100,000 patients use these devices on a regular basis.  [c.88]

SuperchlorinationShock Treatment. Superchlorination or shock treatment of pool water is necessary since accumulation of organic matter, nitrogen compounds, and algae consumes free available chlorine and impedes disinfection. Reaction of chlorine with constituents of urine or perspiration (primarily NH" 4, amino acids, creatinine, uric acid, etc) produces chloramines (N—Cl compounds) which are poor disinfectants because they do not hydrolyze significantly to HOCl (19). For example, monochloramine (NH2CI) is only 1/280 as effective as HOCl against E. coli (20).  [c.298]

By contrast to distilled water, studies in swimming pool water showed greater kill times, even in the absence of cyanuric acid (47). This was attributed to unknown variables, which in reality are swimming pool contaminants. In swimming pools, nitrogenous compounds such as ammonium ion, creatinine, and amino acids, introduced into the pools by bathers, can react with free av Cl. This forms bactericidaHy ineffective combined chlorine, resulting in increased kill times. Studies have shown that addition of ammonia greatiy increases the kill time of S.faecalis by chlorine whether cyanuric acid is present or not (48). By contrast urea, a principal pool contaminant, had no effect. Although urea is a potential source of ammonia, its hydrolysis is very slow under swimming-pool conditions. However, since urea is a nutrient for bacteria and algae, it is necessary to oxidize it by periodic shock treatment.  [c.301]

G s-Sensing Enzyme Electrodes. Potentiometry and amperometry are the most common electrochemical techniques to employ enzyme electrodes. Potentiometric gas-sensing and ion-selective electrodes have been converted into enzyme electrodes and used in various analytical appHcations (53). The gas-sensing electrodes for carbon dioxide and ammonia are most frequendy converted to enzyme electrodes because of the lack of response to any dissolved ionic interferents. Decarboxylating or deaminating enzymes are immobilized to these gas-sensing electrodes so that the enzyme reaction product, CO2 or NH, is detected. These potentiometric immobilized enzyme sensors are highly selective and are used for the detection of urea, creatinine, uric acid, amino acids (qv), and nucleotides, as well as other compounds (50,53). Amperometric electrodes are generally coupled with oxidase or dehydrogenase enzymes. Oxidase enzymes can be immobilized on a Clark oxygen electrode and used to detect the amount of oxygen consumed in the enzyme reaction. For example, in the determination of creatinine in blood semm, the enzymes creatinine amidohydrolase, creatine amidinohydrolase, and sarcosine oxidase are coimmobilized on the polypropylene membrane of a Clark oxygen electrode (60). The enzymes catalyze the decomposition of creatinine with the consumption of oxygen, which is monitored by the Clark electrode. The oxidase enzymes can also be trapped on a platinum electrode and used to measure the amount of hydrogen peroxide produced in the enzyme reaction. For example, glucose oxidase [9001-37-0] covalentiy attached to platinum wire via glutaraldehyde [111-30-8] C Hg02, was used to determine glucose [50-99-7] levels by monitoring the amount of hydrogen  [c.103]

Clearance decreases with increasing permeant molecular weight and depends in complex fashion upon blood and dialysate flow rate and upon device geometry. Detailed engineering analyses are available in References 14—17. As a general rule in most contemporary dialy2ers, the clearance of small solutes such as urea (mol wt = 58), creatinine (mol wt = 113) has either approached a maximum (clearance can never exceed blood flow rate) or is limited by boundary layers adjacent to the membrane for these solutes changes in membrane permeabiUty or membrane surface area will not significantly affect clearance whereas increases in blood flow will lead to increased clearance. In contrast, larger solutes such as inulin (mol wt 5200 daltons) or beta-2-microglobulin (mol wt = 11,118 daltons), are membrane limited. Their clearance will increase, often linearly, with increasing membrane surface area, but will be largely unaffected by changes in blood or dialysate flow rate. These relationships are illustrated in Figure 6 and summari2ed in Table 3.  [c.36]

Renal Failure. High ceiling (loop) diuretics, such as furosemide, bumetanide, ethacrynic acid, piretanide, and torasemide, are the dmgs of choice for the treatment of acute and chronic renal failure, with or without hypertension. Acute renal failure is characterised by a rapid loss of renal function, leading to a rapid development of a2otemia. In acute renal failure that occurs after certain surgical procedures, both mannitol, an osmotic diuretic, and furosemide have been shown to be successful in increasing urine flow and creatinine clearance, but they do not always decrease mortaUty (115,116). Chronic renal failure results from destmction of nephrons and much reduced GER, lea ding to uremia. In these patients, high ceiling diuretics can increase sodium excretion to >50% of the filtered load. The greater the renal impairment, the higher the dose of diuretic is needed. The half-life of the diuretics can increase two- to fourfold in these patients. Mannitol has been found to be useful in maintaining urine flow even at low GERs, such as in hypotension and dehydration (116).  [c.213]

In some patients with IgA nephropathy (IgAN), intraglomerular coagulation plays a role in depositing fibrinogen (235,236). IgAN patients treated with urokinase show a marked improvement in urinary protein concentration, semm creatinine, and blood urea nitrogen levels (237).  [c.312]


See pages that mention the term Creatinine : [c.114]    [c.863]    [c.633]    [c.633]    [c.633]    [c.633]    [c.633]    [c.259]    [c.259]    [c.536]    [c.39]    [c.40]    [c.283]    [c.392]    [c.393]    [c.103]    [c.467]    [c.324]    [c.78]    [c.632]    [c.633]    [c.633]    [c.633]   
Organic syntheses Acrolein (0) -- [ c.4 , c.15 ]

Organic syntheses Acid anhydrides (1946) -- [ c.22 , c.90 ]