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

(1)H, (13)C and (31)P 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. (1)H NMR measurements were performed with a MAS speed of 33 kHz. The intense CH(3), CH(2) and CH peaks in the (1)H spectrum result from fatty acid residues of phospholipids, which are "mobile enough" besides the anhydrous environment. (13)C 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 T(1rho)(H) Overlapped resonances of phospholipids head groups contributed to the peak at 4-7 ppm in the (31)P MAS NMR spectra. Our results indicate that (1)H and (13)C 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.