NMR of biofluids and pattern recognition: assessing the impact of NMR parameters on the principal component analysis of urine from rat and mouse

The ability to interpret metabolic responses to toxic insult as expressed i n altered urine composition and measured by NMR spectroscopy is dependent u pon a database of proton NMR spectra of urine collected from both control a nd treated animals. Pattern recognition techniques, such as principal compo nent analysis (PCA), can be used to establish whether the spectral data clu ster according to a dose response. However, PCA will be sensitive to other variables that might exist in the data, such as those arising from the NMR instrument itself. Thus, studies were conducted to determine the impact tha t NMR-related variables might impart on the data, with a view towards under standing and minimizing variables that could interfere with the interpretat ion of a biological effect. This study has focused on solvent suppression m ethods, as well as instrument-to-instrument variability, including field st rength. The magnitude of the NMR-induced variability was assessed in the pr esence of an established response to the nephrotoxin bromoethanamine. Chang es caused by the model toxin were larger and easily distinguished from thos e caused by using different solvent suppression methods and field strengths . (C) 2001 Elsevier Science B.V. All rights reserved.