Impact of bacteremia on hippocampal apoptosis in experimental pneumococcal meningitis. A. Meningitis controls had significantly lower apoptosis scores* than uninfected controls and than meningitis rats with attenuated bacteremia due to treatment with serotype-specific antibodies (Mann Whitney, P = 0.0003 and P = 0.01, respectively). Bars represent medians. Hippocampal dentate gyrus histology showed sporadic occurrence of apoptotic cells (arrowhead) in rats with attenuated bacteremia (B+C) as compared to meningitis controls having a higher number of apoptotic cells (D+E). * Appearance of apoptotic cells were counted in 4 different slices spanning the hippocampus (3 visual fields in each of the two blades of the dentate gyrus). Each visual field was judged according to the following score: 0-5 cells = 0; 6-20 cells = 1; > 20 cells = 2. A mean value per animal was calculated from all inspected fields (48 fields per animal).