Quantitative Neuropathologic Correlates of Changes in Ratio of N-acetylaspartate to Creatine in Macaque Brain

PURPOSE: To elucidate the neuropathologic basis of transient changes in the ratio of N-acetylaspartate (NAA) to creatine (Cr) in the primate brain by using a simian immunodeficiency virus (SIV)–infected macaque model of the neurologic manifestation of acquired immune deficiency syndrome. MATERIALS AND METHODS: This study was approved by the Massachusetts General Hospital Subcommittee on Research and Animal Care and the Institutional Animal Care and Use Committee of Harvard University. Rhesus macaques infected with SIV were evaluated during the 1st month of infection. A total of 11 animals were studied, including four control animals, three animals sacrificed 12 days after infection, three animals sacrificed 14 days after infection, and one animal sacrificed 28 days after infection. All animals underwent in vivo proton (1H) magnetic resonance (MR) spectroscopy, and postmortem frontal lobe tissue was investigated by using high-spectral-resolution 1H MR spectroscopy of brain extracts. In addition, quantitati...