Figure 4: Immunohistochemical labeling of GFAP. A: Whole mount preparation of frontal cortex from a control shows thin subpial band of gliosis (arrow) and very light labeling of protoplasmic astrocytes. The white matter (w) shows diffuse, low intensity staining. (GFAP, Obj x5). B: Whole mount preparation of frontal cortex from a case of TBM showing thick subpial carpet (arrow) extending into the cortical grey matter. Note the reduced gradient of labeling of grey matter and diffuse dark staining of white matter (w). (GFAP, Obj x 5). C: Low power view of the frontal cortex from a case of TBM shows thick gliotic pial band (arrow) and hypertrophic glial cells in the superficial cortex. Above the pial band in the subarachnoid space, inflammatory exudates are observed. (GFAP, Obj x 10). D: The white matter at higher magnification from the control shows astrocytes with small body and thin long processes, some of them impinging on the vessel wall to form a fine lacy background. (GFAP, Obj x 20). E: Higher magnification of the subpial zone from the case of TBM showing large, hypertrophic reactive astrocytes with darkly labeled body and thick cell processes. The neuropil between the cells also has coarse fibres unlike the control. (GFAP, Obj x 40).