NMR and gas chromatography studies of lyophilized human brain tumors

1H HR MAS (high resolution magic angle spinning) NMR is a promising tool in the in vitro characterisation of brain tumors. Brain tissue samples were collected from patients with intracranial tumors during surgery, frozen and lyophilized. The analysis of solid samples was performed by high-speed rotation (33 kHz) H MAS NMR. The most intense resonances arise from lipids (methylene mid-chain and methyl carbons of fatty acids). 1H MAS spectra obtained from the same histological type of brain tumors are similar; spectra of glioblastomas were different from those of meningiomas. 1H and 13C NMR solution spectra of lipid extracts confirmed the presence of aliphatic chains fatty acids and cholesterol as major constituents. Biochemical information on liberated fatty acid composition was obtained by gas-chromatography (GC). The glioma content of the linoleic acid (18:2n6) was found to be greater, whereas the level of docosahexaenoic acid (22:6n3) was significantly reduced.