The expression of epidermal growth factor receptor (EGFR) was studied in benign and malignant tumors of the breast using a monoclonal antibody of this receptor. The benign lesions were obtained from mastopathy (14 cases), fibroadenoma (12 cases), and malignant lesions, and from papillo-tubular (17 cases), solid-tubular (15 cases), and scirrhous carcinomas (10 cases). The highest incidence of positive EGFR staining was found in the scirrhous carcinomas (70%). The incidence was moderate in tubular carcinomas (60-65%), and low in solid or papillary type (13-35%). Immunolocalization of EGFR staining was divided into 1) luminal-border positive type, 2) cell-membrane positive type, and 3) cytoplasm positive type. In benign lesions, EGFR expression was usually of the luminal border or cell membrane positive type. A heterogeneity of EGFR staining was found in malignant tumors, but evidence suggests in scirrhous carcinoma that EGFR expression is positively correlated with tumor cell proliferation.

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Proliferation of microglia in the mouse cerebral cortex around a stab wound was studied, using thiamine pyrophosphatase (TPPase) histochemistry combined simultaneously with ³H-thymidine (³H-TdR) autoradiography. Many cells with cell membrane TPPase activity (TPPase-positive cells) were scattered in the cortical parenchyma apart from the stab wound. Light and electron microscopically, TPPasepositive cells were identified as microglia but not as astrocytes, oligodendrocytes, or neurons. TPPasepositive cells were immunohistochemically negative for astrocytic markers, i. e., S-100 protein and glial fibrillary acidic protein. Autoradiography showed that approximately 92% of all cells labeled with ³H-TdR within 2 days after stab-wounding were TPPase-positive cells. Approximately 60% of all labeled cells 3 and 4 days after stab-wounding were also TPPase-positive cells. These results suggest that microglia, but not astrocyte, begins active proliferation immediately after injury and is the major cell type having high proliferative activity in the injured cerebral cortex.

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Monoaminergic neuron systems were studied in the frontal sections of the house-shrew brain by using the peroxidase-antiperoxidase technique with antisera to tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC) and serotonin (5-HT). The distribution of monoaminergic neurons was found to be similar to that in the rat brain. However, in the house-shrew brain proper, TH- and AADC-positive cells were found in the diagonal band, stria terminalis, dorsal tegmental nucleus and area postrema, whereas some TH-positive but AADC-negative neurons were found in the diagonal band, lateral septal area, olfactory tubercles, caudoputamen, caudal level of the lateral habenular nucleus and around the dorsal vagal nucleus. Moreover, 5-HT neurons were observed in the motor cortical area, diagonal band, lateral septal area, caudoputamen, lamina intercalaris, periaqueductal gray matter, locus coeruleus, and superior olive. D neurons (AADC-positive but TH- or 5-HT-negative) were observed in the frontal cortex, medial vestibular nucleus, and area postrema. In the dorsal vagal nucleus and its dorsal portion, TH-positive cells started to appear at postnatal day 5 (P5), and the cell number increased between P10-P20, but decreased by adulthood, while D4 and D5 cells first appeared at P1 and gradually decreased until adulthood. Immunoelectron microscopy showed AADC-positive reaction products in the cytoplasmic matrix and granule vesicles in the suprachiasmatic nucleus. Catecholaminergic or serotoninergic nerve fibers and their terminals were widely distributed throughout the brain. Nevertheless, no distinctive distribution or projection of AADC-positive fibers was found.

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We have reported several aspects of a mouse sperm maturation-associated antigen, a 54, 000 dalton (54K) sialoglycoprotein, of which epitope can be masked by sialic acid residues against a monoclonal antibody T21 (35-38). However, the producing cell of the 54K sialoglycoprotein has long been unclear. This report documents the origin of the 54K sialoglycoprotein based on morphological evidence using avidin-biotin peroxidase complex (ABC) immunohistochemistry and indirect immunoperoxidase-electron microscopy with a recently established monoclonal antibody MC81. Immunoblots of Nonidet P-40 extract of cauda epididymidis sperm after one-dimensional, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that MC81 recognized a major protein of 54, 000 dalton (54K). The epitope for MC81 antibody was suggested to be present on a sugar chain of the 54K protein when assessed by periodate treatment. Immunoblots of sperm extracts separated by two-dimensional SDS-PAGE indicated that a major spot of 54K dalton was in acidic range less than 5 in the isoelectric focusing point. These results suggest that the antigen of MC81 is identical to that of T21. Immunohistochemistry with MC81 revealed that principal cells located at the distal caput to corpus epididymidis were immunoreactive. The region where the principal cells were first recognized by MC81 was more proximal than the region where luminal sperm were first stained. In addition, MC81 exclusively recognized the Golgi apparatus area at the supranuclear region of the immunoreactive principal cells. Sialidase-treatment prior to primary antibody (MC81) increased of the immunostaining intensity in all immunochemical studies examined. Together with the result of the previous part of this study, it is strongly suggested that the 54K sialoglycoprotein can be secreted by the principal cells at the distal caput to corpus epididymidis, with the epitope for MC81 masked by sialic acids.

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We made a study on the localization of manganese superoxide dismutase (Mn SOD) and copper-zinc superoxide dismutase (Cu-Zn SOD) in normal lung tissue and lung cancer by immunohistochemical study and quantitative analysis by enzyme immunoassay. In normal lung tissue, both SODs were localized mainly in the bronchiolar epithelial cells. In lung cancer, both SODs were stained intensely in the cytoplasm of cancer cells. Mn SOD and Cu-Zn SOD were immunohistochemically demonstrated in 87% (40 of 46) and 93% (43 of 46) of cases of lung cancer, respectively. The concentrations of Mn SOD and Cu-Zn SOD in tissue of lung cancer (n=73) were significantly higher than those in normal lung tissue (n=26), regardless of the histological type (p<0.01). The Mn SOD contents in non-small cell lung cancer were significantly higher than those in small cell lung cancer. In the sera (n=62) of patients with lung cancer, neither of the SODs was indicated as a useful tumor marker for lung cancer. This indicates that lung cancer tissues have increased levels of Mn SOD and Cu-Zn SOD.

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A cytochemical study using diaminobenzidine (DAB) reaction and horseradish peroxidase (HRP) tracer or DAB reaction alone was performed on junctional epithelium (JE) of young (32-to 42-day-old) and old (100-day-old) rats to investigate how JE cells endocytose the azurophil granules released from neutrophils, as JE cells do with HRP.
HRP was endocytosed by JE cells, and the endocytosed HRP products fused with one another or cytoplasmic vacuoles and formed phagolysosomes of amorphous shape, which digestion of the HRP seemed to be progressive. It was thus certified that JE cells possess endocytotic ability. In old rat gingivae incubated with only DAB medium, neutrophils were found in the JE and contained endogenous peroxidasepositive round, ovoid and elongated azurophil granules. In particular, at the coronal portion of JE, endogenous peroxidase-positive round ovoid and elongated reaction products were numerously detected in the intercellular spaces of the JE cells and within the JE cells. Judging from the cytochemical and morphological resemblances between the endogenous peroxidase-positive reaction products and the azurophil granules in the neutrophils, the reaction products in the intercellular spaces corresponded to the azurophil granules released from neutrophils, and those in the JE cells corresponded to the azurophil granules endocytosed by the JE cells. Furthermore, the endogenous peroxidase-positive reaction products endo cytosed by JE cells also formed the same amorphous phagolysosomes as formed by HRP. It was, therefore, concluded that, at the coronal portion of the JE of old rat gingivae, the JE cells may endocytose and digest lysosomes (azurophil granules) released from neutrophils to protect the gingival tissue.

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