Jejunal endoscopy and histopathological study of biopsied specimens were performed to clarify states of jejunal mucosa and the mechanism of enteric protein loss in six patients with protein-losing enteropathy, including four patients with intestinal lymphangiectasia, one patient with constrictive pericarditis associated with dilated lymphatics of the intestine, and one patient with Budd-Chiari syndrome. Three cardinal endoscopic findings, scattered white spots, white villi, and chyle-like substances covering the mucosa, were demonstrated in protein-losing enteropathy. Scattered white spots indicated markedly dilated lymphatics in the stroma of the villi. White villi seemed to be due to fats including chylomicrons or fat droplets in the absorptive cells, interepithelial spaces, and/or stroma, even though the biopsies were obtained in the fasting state. Therefore, white villi suggest impaired transport of fats from intestinal epithelial cells to intestinal lymphatics. These three cardinal findings are thought to be characteristic for protein-losing enteropathy secondary to lymphatic disorders.

In order to investigate the mechanism of synthesis and secretion of lysozyme (LZ) by human mononuclear phagocytes, the ultrastructural localization of LZ was studied by a pre-embedding direct immunoperoxidase method. Blood monocytes showed a reaction product for LZ in cytoplasmic granules, whereas cultured monocytes showed the reaction product in phagosomes as well as granules at 5 h of culture and in numerous large granules at 3 days of culture. In Kupffer cells, LZ was present in cytoplasmic granules, vacuoles and phagosomes. Some Kupffer cells showed a positive reaction for LZ in the rough endoplasmic reticulum, perinuclear cisterna and Golgi apparatus. Macrophages in the lymph nodes contained LZ in cytoplasmic granules. Bone marrow macrophages contained numerous phagosomes with electron-dense degradation products of erythrocytes, but the reaction product for LZ could not be clearly identified. The present study demonstrated that LZ is present in the granules of human mononuclear phagocytes and released into phagosomes. An in-vitro culture study, furthermore, demonstrated that macrophages produce LZ-containing large granules distinct from those of monocytes. However, findings that indicate the synthesis and secretion of LZ by cultured monocytes, as suggested previously by other investigators, were not observed in this study.

Two cases of myeloproliferative disorders terminating in acute megakaryoblastic leukemia are reported. One case began as primary myelofibrosis and the other as chronic myelogenous leukemia. Blast cells in the acute leukemic phase were identified as megakaryoblasts by the presence of platelet peroxidase. The clinical course is described, and the morphology, immunologic studies, and ultrastructure studies of the blast cells are reported. On cytogenetic analysis both cases had a translocation involving the No. 3 chromosome locus q26.2. The present data suggest that 3q26 may be associated with transformation of the megakaryocytic lineage.

To clarify the origin and function of human cutaneous mast cells (CMCs), immunohistochemical characterization was done in 19 cases of urticaria pigmentosa (cutaneous mastocytosis) using 9 antibodies (anti leukocyte common antigen, MX‐PanB, anti lysozyme, anti α1, antitrypsin, anti α1‐antichymotrypsin, anti vimentin, anti‐neuron specific enolase, anti factor VIII related antigen, and anti‐ACTH). CMCs showed positive reactions with anti α1 anti‐chymotrypsin and anti vimentin in almost all of the specimens. In more than half of the specimens, CMCs were stained positively with anti ‐α1‐antitrypsin, MX‐PanB, and anti factor VIII related antigen. Anti‐leukocyte common antigen and anti ACTH also showed positive reactions in some specimens. These results confirm the existence of vimentin filaments in CMCs and suggest a functional role of CMCs in hemostasis via factor VIII. Furthermore, immunohistochemical similarity between CMCs and granulocyte/macrophage group cells is also suggested.

Pathologic survey was performed on 43 cases of intracranial germinoma and 12 cases of pinealoma. The present study suggests that, in Japan, the incidence of teratoma groups including germinoma is remarkably higher than that in U.S. and Europe, whereas the rate of true pinealoma is lower. Using ultrastructural, enzyme-histochemical, and fluorescence-histochemical methods for a few surgical specimens, a strong similarity between intracranial germinoma (so-called "pinealoma" with a two-cell pattern) and seminoma and dysgerminoma was confirmed. The true pinealoma could be classified as pineoblastoma and pineocytoma, according to the degree of pineocyte differentiation of the tumor cells, and as "neuroblastoma-like" and "pineal-like" on the basis of the histologic architecture.