Analytical Reviews in Clinical Biochemistry: The Estimation of Urea

Taylor, A J; Vadgama, P.

doi:10.1177/000456329202900301

Cited by 74 publications

(55 citation statements)

References 136 publications

(14 reference statements)

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“…Blood urea nitrogen was determined spectrophotometrically using the enzymatic (fixed rate) UV method with urease and glutamate dehydrogenase (20). Serum creatinine concentration was determined spectrophotometrically using buffered kinetic Jaffé reaction without deproteinization method (21).…”

Section: Measurement Of Renal Function Parametersmentioning

confidence: 99%

The efficacy and the immunomodulatory effect of rifaximin in prophylaxis of spontaneous bacterial peritonitis in cirrhotic Egyptian patients

Mostafa

Badra²,

Abdallah³

2015

Turk J Gastroenterol

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Background/Aims: This study aimed to evaluate the efficacy and the immunomodulatory effect of rifaximin as another promising prophylactic therapy against spontaneous bacterial peritonitis (SBP) in cirrhotics. Materials and Methods: Seventy cirrhotic patients with ascites were included in the study. Patients were divided into two groups in a randomized single-blind fashion. Group one (n=40) received rifaximin and group two (n=30) received norfloxacin (control group). The treatment duration was 6 months. Serum levels of tumor necrosis factor alpha (TNF-α), interleukin-6 ( IL-6), and interleukin-10 (IL-10) were the primary inflammatory markers of the study to evaluate the effect of the medications used. Results: Three months after treatment, five cases on norfloxacin therapy showed SBP, whereas all cases on rifaxmine therapy were free from SBP. In addition, there was no significant difference between patients on rifaximin and norfloxacin therapy with respect to TNF-α, IL-6, and IL-10 serum levels (p>0.05). Furthermore, patients on both rifaximin and norfloxacin therapies showed a statistically significant decrease in TNF-α and IL-6 serum levels compared with their baseline levels (p=0.000 and p=0.000, respectively). In contrast, serum IL-10 showed a statistically significant increase in both groups in comparison with its baseline level (p>0.00). Six-month after treatment, patients on rifaximin therapy showed more effective remission from SBP than those on norfloxacin therapy. Conclusion: In conclusion, the use of rifaximin not only prevents bacterial translocation but also modulates the immune response of the inflammatory and the anti-inflammatory cytokines in SBP patients. However, the efficacy and the immunomodulatory effect of rifaximin in the prophylaxis of SBP in cirrhotics needs further prospective large-scale, double-blind studies.

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Section: Measurement Of Renal Function Parametersmentioning

confidence: 99%

The efficacy and the immunomodulatory effect of rifaximin in prophylaxis of spontaneous bacterial peritonitis in cirrhotic Egyptian patients

Mostafa

Badra²,

Abdallah³

2015

Turk J Gastroenterol

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“…2 In whole blood about 45% of its volume is occupied by the formed elements, i.e. red and white blood cells and blood platelets.…”

Section: Interferencesmentioning

confidence: 99%

“…1 A widely accepted reference interval for serum urea is 2.3-8.3 mmol/L, derived from young men on a normal diet, 2 and the value between 24.9-41.5 mmol/L is taken as a conclusive evidence of severe renal impairment. 1 The common direct method for the determination of urea employs the Fearon reaction where urea reacts with diacetyl to form a coloured chromagen, which is then quantified photometrically.…”

Section: Introductionmentioning

confidence: 99%

“…1 The common direct method for the determination of urea employs the Fearon reaction where urea reacts with diacetyl to form a coloured chromagen, which is then quantified photometrically. 1 Disadvantages are the heat requirement and the noxious nature of some of the reagents 2 . Indirect methods employ the enzyme urease to catalyse the hydrolysis of urea and the product is determined.…”

Section: Introductionmentioning

confidence: 99%

“…Urease has been used as free or immobilized enzyme. A major advantage of the latter is the reduction in cost through the reusability of expensive enzyme reagent 2 and several enzyme sensors using immobilized urease have been reported. 4 + + HCO 3 Most urea biosensors are based on potentiometric mode of detection.…”

Section: Introductionmentioning

confidence: 99%

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Thavarungkul¹,

Asawatreratanakul²,

Kanatharana³

et al. 1999

ScienceAsia

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A flow-through enzyme reactor system for the determination of urea using conductimetric measurement is described. Samples are introduced as pulses in a continuous flow of buffer which is passed through a dialyser. The dialysis solution on the other side of the dialysis membrane collects urea molecules from the samples which diffuse through the membrane and is pumped through an enzyme reactor containing urease immobilized to porous glass. Conductivity electrodes are used to measure the increase in conductivity of the dialysis solution resulting from the hydrolysis of urea into charged products. The effects of the flow rate and the possible interferences of cells or NaCl in the sample solutions to the response of the enzyme sensor system have been investigated. The system is used for the determination of urea in standard solutions as well as in human blood serum samples. The enzyme sensor is operated in a linear mode in the concentration range 5-70 mmol/L (correlation coefficient, r = 0.998). Good agreement is obtained when the urea concentrations of human blood serum samples are determined using the enzyme sensor system compared to the diacetyl monoxime colorimetric method (r = 0.997) and to the results obtained by a commercial automated analysis system (r = 0.998).

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A Versatile New Paradigm for the Design of Optical Nanosensors Based on Enzyme‐Mediated Detachment of Labeled Reporters: The Example of Urea Detection

Llopis‐Lorente

Villalonga

Marcos

et al. 2018

Chemistry A European J

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Here, a new bio‐inspired nanoarchitectonics approach for the design of optical probes is presented. It is based on nanodevices that combine 1) an enzymatic receptor subunit, 2) a signaling subunit (consisting of a labeled reporter attached to a silica surface), and 3) a mechanism of communication between the two sites based on the production of chemical messengers by the enzymatic subunit, which induces the detachment of the reporter molecules from the silica surface. As a proof of concept, a urea nanosensor based on the release of Alexa‐Fluor‐647‐labeled oligonucleotide from enzyme‐functionalized Janus gold–mesoporous‐silica nanoparticles (Au–MSNPs) was developed. The Janus particles were functionalized on the silica face with amino groups to which the labeled oligonucleotides were attached by electrostatic interactions, whereas the gold face was used for grafting urease enzymes. The nanodevice was able to release the fluorescent oligonucleotide through the enzyme‐mediated hydrolysis of urea to ammonia and the subsequent deprotonation of amino groups on the silica face. This simple nanodevice was applied for the fluorometric detection of urea in real human blood samples and for the identification of adulterated milk. Given the large variety of enzymes and reporter species that could be combined, this is a general new paradigm that could be applied to the design of a number of optical probes for the detection of target analytes.

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Analytical Reviews in Clinical Biochemistry: The Estimation of Urea

Cited by 74 publications

References 136 publications

The efficacy and the immunomodulatory effect of rifaximin in prophylaxis of spontaneous bacterial peritonitis in cirrhotic Egyptian patients

The efficacy and the immunomodulatory effect of rifaximin in prophylaxis of spontaneous bacterial peritonitis in cirrhotic Egyptian patients

Untitled

A Versatile New Paradigm for the Design of Optical Nanosensors Based on Enzyme‐Mediated Detachment of Labeled Reporters: The Example of Urea Detection

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