H-1-NMR GANGLIOSIDE CERAMIDE RESONANCE REGION ON THE DIFFERENTIAL-DIAGNOSIS OF LOW AND HIGH MALIGNANCY OF BRAIN GLIOMAS

1. The high-resolution H-1 NMR (MRS) spectra of human brain tumor homo genates revealed a broad resonance at 5.3-5.4 ppm in glioblastoma mult iforme (N=16) and brain metastases (N=2). The broad resonance was iden tified as ceramide, a sphingosine-fatty acid combination portion of ga nglioside, indicating an elevated abundance of monounsaturated fatty a cids. GLC analysis of gangliosides in the highly malignant glioblastom a multiforme revealed that the elevated monounsaturated fatty acid is oleic acid (C18:1). The resonance at 5.3-5.4 ppm region was not detect able in normal human brain (N=2), in meningiomas (N=2), or in low-grad e astrocytomas (N=12). In normal human brain the abundance of monounsa turated fatty acid is minimal. 2. This investigation was made possible because the method of producing homogenate resulted in (i) no loss of lipids during the process and (ii) a well-homogenised sample, with (i ii) no loss in chemical integrity. 3. The properties of tumor ganglios ides include antigenic specificity and immunosuppresive activity and t he ceramide, a sphingosine-fatty acid combination, noticeably influenc es the ganglioside immunosuppressive activity. 4. The observation of H -1 NMR ceramide resonance in high-malignant brain tumors emphasizes th e dramatic role of aberrant gangliosides and ceramide precursors on th e grade of malignancy and invasiveness. 5. Further insight into the sp ecific nature of the ceramide portion of gangliosides in grading the m alignancy of brain tumors should be investigated further.