Shinichi Tokumitsu

Monoclonal antibody against ependymoma-derived cell line

SummaryMouse myeloma cells were fused with spleen cells from mice that had been immunized with a human ependymoma derived cell line, KMS II. Hybridomas producing monoclonal antibodies (MAbs) were screened and cloned. Specificity of the antibody was determined by enzyme-linked immunosorbent assay (ELISA) and/or indirect immunofluorescence assay. One of the MAbs, designated Ep-C4 (subclass = IgGl), reacted with two cell lines derived from ependymoma but did not react with 17 cell lines derived from other types of brain tumor nor with 4 neuroblastoma cell lines or 19 cell lines derived from carcinoma, hematopoietic tumors and amnion. Indirect immunofluorescence and immuno-electron microscopy studies revealed that the antigen recognized by MAb Ep-C4 was located on cell surface membrane. The membrane antigen of KMS II cells, immunoprecipitated by MAb Ep-C4, was a protein of 81,000 dalton. The reactivity of MAb Ep-C4 was further examined using immunofluorescence and/or immunoperoxidase methods and frozen sections and short-term cultures of various types of brain tumors. No cross-reactivity with normal adult or fetal brain tissues was detected by absorption assay and immunoperoxidase staining. Our results suggest that the antigen defined by MAb Ep-C4 is specific for ependymoma cells, and different from the antigens of glioma cells or other neuroectodermal-derived cells previously described.

Developmentally heterotopic urogenital tissues in a retroperitoneal lipoma with hematopoiesis

This report concerns an unusual retroperitoneal Hpoma with hematopoiesis in a 49‐year‐old male. A unique feature is the presence of well differentiated male urogenital tissues, such as the prostatic gland, urethra and urinary bladder in part of the tumor. The process of the differentiation of these tissues is also illustrated. Although this Hpoma attained a large size weighing 1,500 g, it is apparently a kind of malformation derived from the sequestered retroperitoneal Wolffian vestige. No similar cases have so far been reported in the world literature.

Deviated formation of intestinal glycocalyx in human stomach cancer cells

SummaryThe process of glycocalyx formation by the trilaminar membrane was investigated at the subcellular level by use of cultivated cancer cells derived from a human stomach adenocarcinoma. Glycocalyx was apparently synthesized on the characteristic trilaminar membrane of Golgi-derived vesicles which gave rise to cytoplasmic vacuoles which, in turn, fused to form an intracytoplasmic cyst. Characteristic microvilli similar to those of intestinal epithelium extended from the membrane lining the intracytoplasmic cyst. These ultrastructural features agree with earlier histochemical findings in suggesting intestinal metaplasia in the origin of the gastric tumor. The morphologic features of the cancer cells clearly indicated that glycoprotein is first synthesized in the Golgi complex and the fully formed mucoprotein then emerges as membrane-bound glycocalyx in the vesicles budding from the Golgi stacks. The glycocalyx layer is an integral part of the external leaflet of the characteristic trilaminar membrane. Abundant deposits of glycocalyx in the intracytoplasmic cyst constituted the ultrastructural basis for a distinctive type of signet ring cell that differed from mucous signet ring cells derived from goblet cells.

EXTRAMEDULLARY HEMATOPOIESIS PRESENTING AS MEDIASTINAL TUMOR

An autopsy revealed extramedullary hematopoietic foci scattered along the thoracic vertebrae and between the ribs in a patient who died of lung cancer. One of them formed a tumor‐like mass adhering to the 10th vertebra, and measured 8 × 6 × 2 cm. The cellular components included erythrocytic, granulocytic and megakaryocytic series at various stages of maturation as well as abundant iron‐pigmented histiocytes. The patient also suffered from chronic hemolytic anemia and secondary hemochromatosis. The intimate relationship of the intrathoracic tumor‐like masses of extramedullary hematopoietic tissue with chronic hemolytic anemia is briefly reviewed.