title: Free magnesium levels in normal human brain and brain tumors: 31P chemical-shift imaging measurements at 1.5 T.
abstract: We have studied a series of normal subjects and patients with brain tumors, by using 31P three-dimensional chemical shift imaging to obtain localized 31P spectra of the brain. A significant proportion of brain cytosolic ATP in normal brain is not complexed to Mg2+, as indicated by the chemical shift delta of the beta-P resonance of ATP. The ATP beta-P resonance position in brain thus is sensitive to changes in intracellular free Mg2+ concentration and in the proportion of ATP complexed with Mg because this shift lies on the rising portion of the delta vs. Mg2+ titration curve for ATP. We have measured the ATP beta-P shift and compared intracellular free Mg2+ concentration and fractions of free ATP for normal individuals (n = 6) and a limited series of patients with brain tumors (n = 5). In four of the five spectra obtained from brain tissue containing a substantial proportion of tumor, intracellular free Mg2+ was increased, and the fraction of free ATP was decreased, compared with normal brain.
authors.affiliation: Department of NMR and Medical Spectroscopy, Fox Chase Cancer Center, Philadelphia, PA 19111.
authors.forename: J S
authors.initials: JS
authors.lastname: Taylor
authors.forename: D B
authors.initials: DB
authors.lastname: Vigneron
authors.forename: J
authors.initials: J
authors.lastname: Murphy-Boesch
authors.forename: S J
authors.initials: SJ
authors.lastname: Nelson
authors.forename: H B
authors.initials: HB
authors.lastname: Kessler
authors.forename: L
authors.initials: L
authors.lastname: Coia
authors.forename: W
authors.initials: W
authors.lastname: Curran
authors.forename: T R
authors.initials: TR
authors.lastname: Brown
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism* / Q000556:secondary; D002294:Carcinoma, Squamous Cell / Q000378:metabolism; D005260:Female; D005909:Glioblastoma / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D010758:Phosphorus; D012016:Reference Values
chemical_list: D010758:Phosphorus; D000255:Adenosine Triphosphate; D008274:Magnesium