Early changes in the 1H-NMR plasma spectrum in patients following breast surgery

The composite methylene (chemical shift between 1.2-1.4 ppm) and methyl (0.8-0.9 ppm) resonances of the 1H-nuclear magnetic resonance (NMR) spectrum were analysed in plasma samples drawn pre- and post-surgery from patients treated for benign or malignant breast tumor. Using a 500 MHz NMR instrument operating at 25 degrees C, the resonances were analysed for line width at half-height and then averaged. The amounts of triglyceride (TG), cholesterol, apolipoproteins A1 (ApoA1) and B (ApoB) were measured in each sample. One week post-surgery, the high-field shoulder of the aliphatic peaks decreased and the composite peaks were weighted down-field compared with spectra obtained pre-surgery. The average line width in patients with malignant tumor observed 1 week post-surgery was narrower than pre-surgery (30.5 +/- 3.9 vs 38.1 +/- 4.2 Hz) (P = 0.01). Line widths observed 1 day post-surgery were not significantly different from pre-surgery values in either patient group. Comparing the methylene and methyl composite peaks, the narrowing in line width observed 1 week post-surgery was more pronounced for the methylene than the methyl line width. The ratio between the height of the composite methylene and methyl peaks was higher 1 week post-surgery (ratio, 2.12 +/- 0.23) than pre-surgery (1.79 +/- 0.37) (P = 0.03), indicative of a relative increase in triglyceride-rich lipoproteins. Compared with pre-surgery levels, TG was higher (1.8 +/- 0.3 vs 1.5 +/- 0.4 mmol/l) (P = 0.05) and ApoA1 lower (1.32 +/- 0.14 vs 1.43 +/- 0.12 g/l) (P = 0.02) 1 week post-surgery. One day post-surgery, decreased levels of lipids and apoliproteins were found. In conclusion, the line narrowing is explained as an effect of the surgical trauma itself. A less contribution to the composite line from high-density (HDL) relative to very-low-density (VLDL) lipoprotein is suggested as one mechanism for line width narrowing observed after surgery.