Intracranial self-stimulation in female and male rats: no sex differences using a rate-independent procedure

Neopterin concentrations in diverse body fluids provide a well established indication for activation of the cell-mediated immune system. Neopterin concentrations were measured in the saliva and urine of 29 patients with varying numbers of teeth affected by periodontitis. While neopterin concentrations in urine increased slightly but not significantly in parallel with increasing numbers of affected teeth, salivary neopterin levels showed a significant and positive correlation with number of diseased teeth (linear correlation coefficient = 0.48, P = 0.012). Additionally, when the patients were grouped according to the median number of affected teeth (20), salivary specimens of subjects with one to 20 affected teeth showed significantly lower neopterin concentrations than specimens from those with more than 20 diseased teeth (P = 0.0045, Student's t-test). In contrast, urinary neopterin concentrations did not differ significantly among these two groups. This pilot study suggests that salivary neopterin concentrations may reflect local immune activation even in situations where no systemic activation can be detected.