Brain function estimated from the ratio of glutamine to homocarnosine levels in cerebrospinal fluid.

The ratio of glutamine to homocarnosine (G/H ratio) in CSF of children with meningeal pathology or convulsions was measured and the following results were obtained. 1. The mean G/H ratio of normal subjects was 83.0 +/- 41.4. 2. The mean G/H ratios of the patients with bacterial meningitis and meningeal leukemia were 115.9 +/- 81.9 and 115.2 +/- 49.2, respectively. Significant differences were found between those in normal subjects and these diseases. 3. The mean G/H ratio of the patients with viral meningitis was 80.0 +/- 35.1 and no significant difference was found between normal subjects and these patients. 4. The mean G/H ratios in the patients with controlled versus uncontrolled epilepsy were 130.9 +/- 67.1 and 74.8 +/- 49.4, respectively. A significant difference was found between normal subjects and the patients with controlled epilepsy. 5. The mean G/H ratio in the patients with febrile convulsions was 46.5 +/- 6.3. A significant difference was found between normal subjects and these patients. These data suggest that a high G/H ratio in CSF may indicate the excited state of the brain.