The authors have studied the distribution of factor Vi-related antigen (FVMR: Ag) using both immunohistochemical and immunoelectron microscopic techniques with periodate-lysine-paraformaldehyde fixation and tubular bodies (Weibel-Palade bodies) in endothelial cells in 15 cases of gliomas and 3 samples of non-tumor brain tissue. Twelve glioblastoma, 1 ependymoma, 1 astrocytoma grade II, and 1 oligodendroglioma were evaluated. On FVIIIR: Ag study 7 non-filial tumors (2 metastatic tumor, 3 meningioma, 1 hemangioblastoma, and 1 chordoma) were compared with gliomas.
FVIIIR: Ag was localized to the vascular lumen, to the intercellular spaces between endothelial cells (apparently without tight junctions), and to the endothelial cell basement membrane. In the cytoplasm of the endothelial cells FVIIIR: Ag was found in the endoplasmic reticulum, perinuclear space, intracytoplasmic vacuoles, vesicles, and luminal surfaces of endothelial cell membranes. Characteristic of malignant tumors (6 out of 7), especially in the cases having endothelial proliferation or hyperplasia, it was strongly-positive at the dilated endoplasmic reticulum, whereas only 1 of 5 benign tumors showed such staining. These findings suggest that FVfIR: Ag synthesis occurs more effectively in the endothelial cells of malignant tumors, such as glioblastoma.
The tubular body (Weibel-Palade body) observed in the endothelial cells of the glioma vessels consisted of a membrane-limited round, oval or elongated intracytoplasmic body (about 0.1-0.2 μm) which contained tubules of 150-200 Å outer diameter. Tubular bodies were classified into two types. One of them, mature type, is relatively electron dense, the other, immature type, has a relatively pale matrix. The immature types were located in close proximity to the Golgi complex or endoplasmic reticulum. Tubular bodies were common only in the endothelial cells in the marginal zones of glioblastoma with respect to the increased microvessels. In the endothelial cells of glioblastoma they appeared more prominently consistent with neovascularity than with benign glioma. It is suggested that large numbers of tubular bodies may be a marker for proliferating endothelial cells.
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