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Clinical 1H spectroscopy of the brain is complemented by parallel analyses of biopsy specimens and by studies of animal models of disease. 1H spectroscopy has been carried out on perchloric acid extracts of biopsy specimens from patients with intracranial tumours. The data suggest that clinical spectroscopy may be useful in the identification and grading of these tumours. In addition, the spectra from extracts derived from normal white matter add weight to the possibility that acetyl-containing compounds other than N-acetylaspartate may make a significant contribution to the signal at 2.0 ppm in vivo. Edited 1H spectra of brain metabolites in rats with acute liver failure demonstrate an elevation of glutamine and of lactate, suggesting a role for 1H spectroscopy in clinical investigations of metabolic encephalopathies. However, the observation and resolution of signals from glutamate and glutamine is more difficult at the lower fields that are available for clinical spectroscopy. Finally, some studies of patients with inborn errors of metabolism are described. It is shown that in a disorder of oxidative metabolism, brain lactate can be detected without the need for complex spectral editing techniques. Investigations of the metabolic abnormalities associated with Canavan's disease have shed further light on a possible role for N-acetylaspartate.

31P NMR spectroscopy was used in conjunction with conventional biochemical techniques to study metabolic abnormalities in normal rats, in rats with CCl4-induced acute liver failure and in rats with paracetamol-induced acute liver failure. Studies were carried out before and after a metabolic challenge in the form of a fructose infusion. Prior to fructose infusion the ATP levels in the groups with acute liver failure were significantly lower than in control rats, despite their having a similar ATP/Pi ratio. Following a fructose infusion in control animals, the changes in phosphomonoesters, ATP and inorganic phosphate were consistent with previously reported findings. However, in both test groups the percentage changes in phosphomonoesters and ATP were significantly smaller. Intracellular pH declined in control animals, but did not change significantly in the animals with acute liver failure. Fructose clearance from the blood in control animals was not significantly different from that in animals with CCl4-induced acute liver failure. Metabolic changes measured using a horizontal magnet were very similar to those obtained with a vertical magnet.

1H NMR spectroscopy of brain extracts was used to investigate the metabolic changes that take place during development of the neonatal rat brain. Data were obtained over the range 1-21 days. The concentration of N-acetylaspartate rose by a factor of 9 during this period, the most rapid rise occurring after day 9. The total creatine concentration rose from days 1-21, with a large increase between days 1 and 5. Taurine concentration rose until day 5, then fell from days 5-21. The concentration of choline-containing compounds fell during the 21 day period. The results are discussed in relation to brain development and conventional biochemical data. A major conclusion in relation to spectroscopy of children is that interpretation of changes seen in disease will require adequate data from age-matched controls.