title: Intracellular free magnesium of brain and cerebral phosphorus-containing metabolites after subarachnoid hemorrhage and hypermagnesemic treatment: a ³¹P–magnetic resonance spectroscopy study. Clinical article.
abstract: OBJECTIVE
  Disturbance of cerebral phosphorus-containing metabolites occurs in many disease entities and has not been widely studied in patients with subarachnoid hemorrhage (SAH). Pilot studies have indicated that hypermagnesemic treatment may improve outcome in patients with aneurysmal SAH, but the precise mechanism is not known. The authors hypothesized that, by raising intracellular brain free magnesium in aneurysmal SAH, hypermagnesemic treatment would alter the cerebral energy status.
  
  
  METHODS
  The authors designed the current study to use ³¹P-MR spectroscopy (MRS) to investigate intracellular brain free magnesium and cerebral phosphorus-containing metabolites in patients with good-grade aneurysmal SAH, both those receiving and not receiving hypermagnesemic therapy. A total of 37 eligible patients and 23 healthy volunteers were recruited. A total of 81 MRS studies were performed.
  
  
  RESULTS
  Hypermagnesemic treatment after aneurysmal SAH produced a small (mean difference 0.018 ± 0.007 mM [+ 13.0%]) but significant elevation of intracellular free magnesium during the 1st week. Aneurysmal SAH produced a depressed membrane metabolism with lower phosphodiester/total phosphate.
  
  
  CONCLUSIONS
  The MRS finding of elevated brain free intracellular magnesium after intravenous magnesium sulfate infusion is novel, and the changes in membrane metabolism provide insight into the metabolic effects of aneurysmal SAH and future pathophysiological studies.
authors.affiliation: Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China. georgewong@surgery.cuhk.edu.hk
authors.forename: George K C
authors.initials: GK
authors.lastname: Wong
authors.forename: David K W
authors.initials: DK
authors.lastname: Yeung
authors.forename: Anil T
authors.initials: AT
authors.lastname: Ahuja
authors.forename: Ann D
authors.initials: AD
authors.lastname: King
authors.forename: Christopher W K
authors.initials: CW
authors.lastname: Lam
authors.forename: Matthew T V
authors.initials: MT
authors.lastname: Chan
authors.forename: Tony
authors.initials: T
authors.lastname: Gin
authors.forename: Wai S
authors.initials: WS
authors.lastname: Poon
mesh_terms: D000328:Adult; D000368:Aged; D001923:Brain Chemistry / Q000187:drug effects*; D002545:Brain Ischemia / Q000150:complications; D003128:Coma / Q000209:etiology; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D008274:Magnesium / Q000097:blood / Q000378:metabolism*; D017616:Magnesium Compounds / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D010758:Phosphorus / Q000378:metabolism*; D010759:Phosphorus Isotopes; D013345:Subarachnoid Hemorrhage / Q000378:metabolism* / Q000628:therapy*
chemical_list: D017616:Magnesium Compounds; D010759:Phosphorus Isotopes; D010758:Phosphorus; D008274:Magnesium