Value of sodium dodecyl sulfate polyacrilamide gel electrophoresis in evaluation of pediatric urinary tract infections

Abstract

Urinary tract infections (UTI) represent frequent health problem, especially in developing countries. Clinical signs are different based on the location of infection. An interesting ethical and professional question arises: how to treat febrile children who previously received antibiotic therapy and have sterile urine culture in presence of pyuria. Is that a pyelonephritis and are further invasive imaging studies needed? Objectives: To analyze the electrophoretic patterns of urinary proteins in children with proximal respectively distal UTI and to evaluate the value of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) in acute febrile respiratory infections (AFRI) without signs and symptoms of UTI. Material and methods: The study included 79 children aged 1-16 years: 36 with proximal UTI (15 with culture positive APN, respectively 21 with culture negative APN), 23 with cystitis (7 with hemorrhagic cystitis) and 20 children with AFRI without symptoms of UTI. Separation of urinary proteins was performed by SDS-PAGE. Results: Children with culture positive and culture negative APN had incomplete tubular proteinuria (24-67 kDa) which was transient. Hemorrhagic cystitis was characterized by the typical presence of 28 kDa band (apolipoprotein A-1). In the group AFRI without symptoms of UTI, there was no observed pathological electrophoretograms. Conclusions: SDS-PAGE is useful laboratory technique for separating proteins by their molecular size. The presence of incomplete tubular proteinuria indicates the renal origin of the fever. Detection of apolipoprotein A-1 in children with hemorrhagic cystitis allows differentiation in relation to glomerular cause bleeding. Despite these facts, in the literature there are few reports on SDS-PAGE in diagnosis of various renal diseases including urinary tract infections.