Renal markers

A plethora of methods has been developed to evaluate renal function by dynamic renography and remote analysis of the excretion of renal function markers. The underlying principle is that the kidneys excrete a majority of small hydrophilic molecules and their clearance, secretion, or fixation in the kidney is quantifiable. When a renal marker in plasma is filtered through the glomeruli, the accumulation of the filtrate in the Bowman s capsule. One or more of the following events may occur in the renal tubule once a marker is filtered or is in plasma [171] ... 

In addition to its content in the glomerular filtrate, the marker is secreted by the renal tubule. Its clearance rate is used to measure renal blood flow but it overestimates the GFR. The aniline derivatives,p-amino hippurate (PAH) or radiolabeled o-iodohippuxan (OIH), represent this group of renal markers. Note that PAH is partly filtered by the glomerular membrane, but molecules that are exclusively excreted by the renal tubules would be ideal for renal blood flow measurements. 

J. Wang, On-chip enzymatic assays, Electrophoresis, 23 (2002) 713-718. J. Wang and M.P. Chatrathi, Microfabricated electrophoresis chip for bioassay of renal markers, Anal. Chem., 75 (2003) 525-529. 

Various papers related to the simultaneous determination of creatinine and uric acid can be found in the hterature. Several authors have developed capillary zone electrophoresis (CZE) methods for simultaneous analysis of these compounds in urine. The CE analysis of these renal markers offers some advantages when compared with chromatography, such as shortened separation time, reduced reagent consumption, and increased resolution. Capillar micellar electrokinetic chromatography has been applied to the simultaneous separation of creatinine and uric acid in human plasma and urine. However, chromatographic techniques are widely accepted for the determination of these compounds. Reversed-phase and ion... 

An assay for uric acid in urine employing a PDMS and/or glass microchip for capillary electrophoresis has also been developed. This device can achieve separation and quantitation of uric acid in less than 30 seconds and a linear response over a range of 0 to lOOpM/L. To facilitate this measurement, dilutions of urine of the order of fiftyfold to seventy-fivefold were required. Other similar devices for the renal markers creatine, creatinine, p-aminohippuric acid, and uric acid in urine,and a microchip-based method for zone electrophoretic analysis of oxalate m urine have been reported. 

Wang J, Chatrathi MP. Microfabricated electrophoresis chip for bioassay of renal markers. Anal Chem 2003 75 525-9. 

Kramer J, Steinhoff J, Klinger M, Ericke L, Rohwedel J. 2006. Cells differentiated from mouse embryonic stem cells via embryoid bodies express renal marker molecules. Differentiation 74(2-3) 91-104. 

Garcia-Martmez JD, Tvarijonaviciute A, Cer6n JJ, Caldin M, and Martmez-Subiela S. Urinary clusteiin as a renal marker in dogs. J Vet Diagn Invest. 24(2) 301-6, March 2012. 

European children (N = variable with outcome, 300-600 children) Serum creatinine, cystatin C Inverse association of increasing PbB and lower renal markers (hyperfiltration) De Burbure et al. (2006)... 

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