Patent ID: 7892845

Claim:
A method for measuring the in vivo metabolism of a protein synthesized in the central nervous system (CNS) of a subject, the method comprising: a. administering a labeled moiety to the subject, the labeled moiety being capable of crossing the blood brain barrier and incorporating into the protein as the protein is synthesized in the CNS of the subject; b. obtaining a cerebral spinal fluid (CSF) sample from the subject, the CSF sample comprising a protein fraction synthesized in the CNS and detectably labeled with the moiety and a protein fraction not labeled with the moiety, wherein the labeled protein fraction in the CSF sample is detected with a mass spectrometer; c. detecting the amount of labeled protein and the amount of unlabeled protein, wherein the ratio of labeled protein to unlabeled protein is directly proportional to the CNS metabolism of the protein in the subject; and d. calculating the labeled protein fractional synthesis rate (FSR) or the labeled protein fractional clearance rate (FCR) between 6 hours and 36 hours after administration of the labeled moiety.