Kazuo Tabuchi

The ultrastructure of pinealomas.

SummaryFour pinealomas of the two-cell type (atypical teratomas) were investigated by electron microscopy. They all showed the same unique histological ultrastructure. The lymphocyte-like cells did not differ ultrastructurally from lymphocytes. Many plasma cells with well-developed rough surfaced endoplasmic reticulum were also seen. The small cells and the plasma cells were considered to be derived from blood cells. A variety of the large cells in the process of differentiation were observed. They had a large and ovoid nucleus with uniform granular chromatin and contained one or more prominent nucleoli. The large cells had many dilated cytoplasmic cisternae, numerous glycogen granules of about 250–300 Å in diameter and annulate lamellae. Ultrastructurally, the pinealoma of the two-cell type resembled the seminoma of testis which is of germ cell origin. This suggests that the pinealoma may be of germ cell origin.

Immunohistochemical localization of S-100 protein in human cerebral and cerebellar cortices.

S-100 protein, a highly acidic protein specific to the nervous system, is immunohistochemically localized exclusively in glial cells, but not in any type of neuron in human cerebral and cerebellar cortices.

Evaluation of the drug-induced morphological differentiation of rat glioma cells (C-6) from the aspects of S-100 protein level and con a binding pattern ☆

The intracellular content of the nervous system specific protein S-100 began to increase with 4 days latency following the morphological differentiation of cultured rat glioma cells (C-6) with 1 mM dibutyryl cyclic AMP (dbcAMP), rising to approximately 10-fold over the control level at 15 days after the treatment. The concanavalin A (Con A) binding pattern on the external cell surface of C-6 cells exposed to dbcAMP appeared as a smooth layer of 40-60 nm thickness whereas that of control cells was irregularly thick and patchy. The correlation between morphological and biochemical changes of C-6 cells after dbcAMP treatment is discussed in relation to the mechanism controlling the differentiation of glioma cells.

Characteristics of a brain lymphoma cell line derived from primary intracranial lymphoma

A brain lymphoma cell line, designated TK, was established from biopsy material of a patient with primary intracranial lymphoma. The TK cell line grew in suspension with clumps of cells and consisted of primitive lymphoid cells. TK cells and original lymphoma cells from which the cell line was derived bore surface immunoglobulin and lacked Epstein‐Barr virus‐determined nuclear antigen. Transplantation of the TK cells into immunosuppressed newborn hamsters gave rise to invasive growth of tumors with metastasis to the brain and eyes. These findings provide definitive evidence for a B‐cell origin of the brain lymphoma in this case.

S-100 protein in human glial tumours. Qualitative and quantitative studies.

SummaryThe authors studied a total of 48 human glial tumours for S-100 protein, an extremely acidic protein specific to the nervous system, by immunohistochemistry and by micro-complement fixation assay in order to evaluate S-100 protein as an index for malignancy of glial tumours.All of 48 glial tumours analyzed in the present study demonstrated variable amounts of S-100 protein which might serve as a biochemical cell marker for glial tumours. The mean value of S-100 protein content in 3 ependymomas is higher than those of 19 low-grade (grades I, II) astrocytomas and 26 high-grade (grades III, IV) astrocytomas, being lowest in the latter. A statistically significant (p<0.001) difference in S-100 protein levels between low-and high-grade astrocytomas is observed, but not for ependymoma. At present, however, no correlation can be found between S-100 protein content of a tumour and the patients survival time.Immunoperoxidase staining for S-100 protein in high-grade astrocytomas is generally weak in intensity and heterogeneous throughout the section, whereas that in low-grade astrocytomas and ependymomas is relatively strong and homogeneous, indicating that high-grade astrocytomas consist of a more heterogeneous population of tumour cells in terms of S-100 protein.These results show that the investigation of S-100 protein in a glial tumour is valuable to a certain extent in assessing the degree of differentiation or malignancy of the tumour.

Detection of IgG on glioblastoma cell surfacein vivo

SummaryEighteen human brain tumours including nine glioblastomas have been examined for the presence of IgG in the tumour tissue by the direct immunoperoxidase technique. Three of nine glioblastomas had IgG on the surface membranes of the tumour cells, and the possible meaning of this is briefly discussed.

Effects of cyclic AMP on S-100 protein level in C-6 glioma cells

Dibutyryl cyclic AMP (dbcAMP) markedly elevated S-100 protein level in C-6 glioma cells in vitro. Quantitative analysis by two-dimensional polyacrylamide gel electrophoresis revealed that the elevation was caused by a combination of increased synthesis and reduced degradation of S-100 protein in C-6 cells exposed to dbcAMP. These results suggest that dbcAMP affects both the synthesis and the degradation of S-100 protein in C-6 cells.

Immunohistochemical demonstration of IgG in meningioma

SummaryTwenty human meningiomas were examined for IgG and IgM by the direct immunofluorescence or immunoperoxidase methods, or both. IgG was conspicuously found in and around the blood vessels, whorls, and psammoma bodies. It was also clearly present on the cytoplasmic membranes of the tumour cells. On the other hand, IgM was seen only within the blood vessels.Significance of these findings is briefly discussed including possible humoral immune reactions in regard to whorl and psammoma body formation in meningioma.

Immunocytochemical evidence for SV40-related T antigen in two human brain tumours of ependymal origin

SummaryA series of thirty-nine human brain tumours has been screened for the presence or absence of SV40-related T antigen by the direct and indirect immunoperoxidase techniques. Two tumours (an ependymoma and a choroid plexus papilloma) of ependymal origin revealed markedly positive nuclear staining for T antigen both in in vivo and in vitro. The possible viral etiology of these human brain tumours is discussed in relation to recent human papovavirus isolates.

Localization of SV40 T antigen in mitotic cells by an immunoperoxidase method

The immunoperoxidase technique has clearly demonstrated that SV40 T antigen is dissociated from the chromosomes in mitotic cells, and massive transport of T antigen from the cytoplasm to the nucleus appears to take place during or immediately after the telophase.