iNOS staining in cerebral malaria brains and in control brains. A: Category A cerebral malaria (no discernible histological changes except the occasional rare malarial pigment within vessels) frontal lobe showing negligible vascular wall iNOS. B: Category B (no discernible changes except significant sequestration of parasitised erythrocytes) occipital region showing negligible vascular wall iNOS. C: Category C (microhemorrhages, significant mononuclear cell accumulations, and also sequestered parasites) frontal lobe showing notably more vascular wall iNOS than seen in categories A or B. D: Mononuclear cells in Category C frontal lobe staining in parallel with the vessel walls for iNOS. E: iNOS immunostaining in mid-brain of Caucasian control brain. F: iNOS immunostaining in pons region of a childhood Malawi control brain. Scale bar, 100 μm.