title: Urine protein profiling with surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry.
abstract: BACKGROUND
  In the last few years there has been an increasing interest in exploring the human proteome. In particular, efforts have focused on developing strategies to generate reproducible protein maps of normal cells, tissues, and biologic fluids, from which studies can then compare protein expression between different groups (e.g., healthy individuals vs. those with a specific pathologic state).
  
  
  METHODS
  Various extrinsic factors (instrument settings, matrix composition, urine storage post void, freeze-thaw cycles) and intrinsic factors (blood in urine, urine dilution, first-void vs. midstream urine) were analyzed with respect to their impact on urine protein profiling using surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS).
  
  
  RESULTS
  Extrinsic factors that critically influenced reproducibility and peak detection of urine protein profiling were matrix composition and instrument settings, while freeze-thaw cycles had minimal impact. Midstream urines samples did not undergo changes in their protein profile when stored for three days at 4 degrees C. Intrinsic factors that influenced normal urine protein profiling were blood in the urine and urine dilution. Female first-void urine had a significantly different ratio of proteins present compared to a midstream urine sample. Limitations of the SELDI-TOF-MS technique included ion suppression and quantification of individual proteins when protein composition was complex.
  
  
  CONCLUSIONS
  SELDI-TOF-MS offers a unique platform for high throughput urine protein profiling; however, standardization of analysis conditions is critical, and both extrinsic and intrinsic factors must be taken into account for accurate data interpretation.
authors.affiliation: Immunogenetics Laboratory, Faculty of Medicine, Winnipeg, Manitoba, Canada.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schaub
authors.forename: John
authors.initials: J
authors.lastname: Wilkins
authors.forename: Tracey
authors.initials: T
authors.lastname: Weiler
authors.forename: Kevin
authors.initials: K
authors.lastname: Sangster
authors.forename: David
authors.initials: D
authors.lastname: Rush
authors.forename: Peter
authors.initials: P
authors.lastname: Nickerson
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D040081:Protein Array Analysis / Q000379:methods* / Q000592:standards; D040901:Proteomics / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014556:Urine / Q000737:chemistry*