1H, 13C and 31P MAS NMR studies of lyophilized brain tumors

1H, 13C and 31P magic angle spinning magnetic resonance spectra (MAS NMR) of lyophilized brain tissue specimens were recorded. Among the 35 cases of brain tumors there were 24 glioblastomas, seven meningiomas and a few other types. 1H NMR measurements were performed with a MAS speed of 33 kHz. The intense CH3, CH2 and CH peaks in the 1H spectrum result from fatty acid residues of phospholipids, which are “mobile enough” besides the anhydrous environment. 13C CPMAS spectra revealed the resonances of creatine and guanidine carbons; the high intensity signals arise from carbonyl groups and methylene carbons of lipids. In particular we found a fraction of mobile lipids, characterized by narrow resonances and long T1ρH Overlapped resonances of phospholipids head groups contributed to the peak at 4-7 ppm in the 31P MAS NMR spectra. Our results indicate that 1H and 13C MAS NMR are able to characterize tumor types: differentiate glioblastomas from meningiomas and shed light on tumor biochemical characteristics. However, water soluble metabolites are not observed and macromolecules yield broad overlapped resonances. Generally, lyophilization significantly decreases discriminative potential of NMR analysis.