Evaluation of pediatric nephropathies by a computerized Urine Protein Expert System (UPES)

Abstract

A computerized Urine Protein Expert System (UPES) measuring creatinine, total protein, albumin, IgG, alpha(1)-microglobulin, alpha(2)-macroglobulin, and N-acetyl-beta-D-glucosaminidase, together with urine dipstick testing for granulocyte esterase and hemoglobin pseudoperoxidase, and measurement of serum creatinine had been found to be useful in adults for differentiating between renal disorders. The objective of this study was to investigate UPES for identifying the different types of proteinuria and their underlying prerenal, glomerular, tubular, and postrenal causes in 146 children characterized by routine and invasive nephrological investigations. UPES proved to be a useful tool in pediatric renal patients after refinements were implemented in the program. Comparing UPES with the pediatric nephrologist's interpretation of all available clinical and laboratory data, UPES diagnosed glomerulopathies in 46 (75%) of 61 patients. In a further 23% it suggested glomerular involvement by indicating either a disturbed glomerular permeability or increased excretion of albumin. Tubular proteinuria was correctly described by UPES in 23 (100%) patients with different tubulopathies. UPES revealed normal kidney function in all healthy children and all children with remission of renal disorders. Therefore, UPES can be regarded as a useful tool in the automated differentiation of renal diseases in children.

Increased cystatin C concentration in urine of nephrotic children

“…We cannot exclude, however, that the "solvent drag" phenomenon could also be responsible for the observed effect of increased urinary excretion of cystatin C in the presence of massive proteinuria. This was observed in the case of another low molecular weight protein a 1 -microglobulin by Lun et al [8].…”

Combination of ceftriaxone and acyclovir – an underestimated nephrotoxic potential?

“…Both low molecular weight and microalbumin concentrations were similar in those patients, suggesting a tubulopathy [17], while the predominant excretion of albumin would be suggestive of a glomerular disorder. The renal biopsy is of interest as it supports the concept of a direct tubulotoxic mechanism of damage imposed by the combination of both drugs.…”

Urinproteomanalytik

“…B. Albumin und α1Mikroglobulin erlaubt eine Differen zierung in glomeruläre und tubuläre Pro teinurie (AAAUrinexpertensystem; [2]). Die Erweiterung dieses Expertensystems mittels UPESSystem ("urine protein ex pert system", PROTIS®) erlaubt zusätzlich eine Differenzierung in renale und post renale Schädigungstypen [3]. Die Geschichte der Proteomanalyse ist durch mehrere Phasen gekennzeich net, die auch bei anderen neuen Labor methoden zu finden waren.…”