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An immunohistochemical analysis of formalin-fixed, paraffin-embedded brain sections was performed with antisera against holoferritin and the light(L)-subunit of ferritin. Sections immunostained using anti-glial fibrillary acidic protein (GFAP), Ricinus communis agglutinin-1 (RCA-1) stain for microglia and iron stain (Berlin blue stain) were compared. The L-subunit of ferritin was purified from normal human spleen according to the modified scrapie-associated fibrils purification, and the anti-serum was raised in a rabbit. Both ferritin antisera positively stained resting and, more markedly, reactive microglia, both of which were also stained with RCA-1 but not with GFAP. Ferritin-positive resting microglia were seen more abundantly in cerebral and cerebellar cortices than in white matter. The advantages of ferritin antisera over RCA-1 are as follows. (1) RCA-1 heavily stains blood vessels, while anti-ferritin does not, hence the microglial cells are more readily visualized with ferritin immunohistochemistry. (2) Reactive microglia and macrophages are more strongly stained with anti-ferritin. (3) The staining intensity of ferritin is independent of the length of tissue fixation in formalin. However, anti-ferritin is inferior to RCA-1 in staining resting microglia with a scanty cytoplasm, especially in the white matter, probably because the former recognizes cytoplasmic components, while the latter recognizes cell membrane. Iron stain only gave a reaction to microglial cells in brains with neurosyphilis and to hemosiderin-laden macrophages. Thus, in addition to RCA-1, ferritin antisera are useful as a microglia marker in formalin-fixed, paraffin-embedded sections.

Three cases of patients with unusual neuronal tumors in the cerebral hemisphere are reported. All were associated with long‐standing epileptic seizures. Computed tomography disclosed low‐density lesions without contrast enhancement, which were interpreted as either arachnoid cysts or a cerebral infarction at initial diagnosis. Magnetic resonance imaging scans, however, revealed the lesions to be solid tumors. At surgery, the tumors were found to be relatively well demarcated, soft, and gelatinous. Histologically, all tumors were composed of small uniform stellate cells, which proliferated in a loose myxoid fibrillary matrix and resembled either oligodendroglial or astrocytic tumors. Ultrastructurally, however, all tumors showed neuronal differentiation, including numerous clear and occasional dense‐core vesicles, microtubules, and a number of synapses. A review of the literature uncovered no other such cases, and therefore it was decided to classify these tumors as a distinct group of benign neuronal tumors, designated as “cerebral” neurocytoma compared with “intra‐ventricular” neurocytoma. Related nosologic problems of neuronal tumors of the central nervous system and their possible histogenesis are also discussed. Cancer 1992; 70:529–537.

A case of clival chordoma in a 4-year-old girl is presented. The tumor regrew rapidly after it was partially removed, and the patient died after a clinical course of 11 months. An autopsy revealed a massive clival mass and widespread metastases in the dura mater, skull bone, bilateral lungs, liver, sternum, left humerus, and vertebrae. Pathological findings showed that the tumor cells were poorly differentiated, with a rare, but typical, physaliphorous appearance. The presence of epithelial differentiation proteins, mitochondria surrounded by rough endoplasmic reticulum, and desmosomes was demonstrated in the tumor cells both immunohistochemically and ultrastructurally. Thus, the tumor was diagnosed as a chordoma. The literature pertaining to intracranial chordoma in early childhood is reviewed. Rapid growth and distant metastases may occur in chordomas at a young age.

Glycosyltransferase gene transfection into cell lines has been an approach used successfully to elucidate the functional role of cell surface glycoconjugates. We have transfected the rat CMP-NeuAc:Gal/31 ‚4GIcNAc cn2,6-sialyltransferase (EC 2.4.99.1) gene into a human, tumorigenic, glioma cell line, U373 MG. This transfection led to a marked inhibition of invasivity, alterations in adhesivity to fibronectin and collagen matrices, and inappropriately sialylated cr3ßl integrin. Adhesion-mediated protein tyrosine phosphorylation was reduced in the transfectants despite increased expression of focal adhesion kinase, pl2 5fak Furthermore, the transfectants

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We performed histochemical studies on normal human and rat tissues using anti-GalP1,4GlcNAc a2,6-~ialyItransferase (a2,6-ST) antibody and Sambucusnigra agglutinin (SNA). a2,6-ST and its products were detected in almost all tissues examined. However, the staining intensities varied significantly with di&rent cell types. Some seaetory epithelial cells, such as hepatocytes and choroid plexus cells, were vividly stained with either anti-aZ.6-ST or SNA. In several cell types the intensity of a2,6-ST staining did not always correlate with SNA stainability. Neurons and gastrointestinal epithelia were rarely stained with SNA, even though they were positive for a2,6-ST. In contrast, the endothelial cells of blood vessels strongly reacted with SNA despite their weak a2,6-ST expression. The precise physiological roles played by a2,6-linked sialylated glycoconjugates have been unclear. However, the fmdiags desaibed here lend fiuther support to their important role in cell growth and difkrentiation, since immature blood cells, including megakaryocytes in bone marrow, were intensely stained with anti-al,dST and SNA, and SNA reaction praducts were primarily observed in the basal and suprabasal layers of the stratified epithelia rather than in the more a e n t i a t e d upper layers. In view of the vivid reactivity ofantLa2,CST io the decidual cells of the placenta, it seem likely that a2,6-ST expression is under hormonal control. (J I l i s t d e m C y t d e m 43945-954, 1995)

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