The gap junctions in rabbit ovarian granulosa cells were examined by morphometrical and cytochemical studies for adenylate cyclase activity during the follicle maturation and ovulatory process. The surface gap junctions, which were observed very early even in the preantral follicles with two layers of granulosa cells, increased significantly in both size and frequency during the follicle maturation. After the ovulatory stimulation by human chorionic gonadotropin (hCG), the surface gap junctions decreased significantly until 9hr, the time just prior to ovulation. In comparison, the annular gap junctions, which were first observed at around the time of antrum formation and frequently found in the neighborhood of surface gap junctions, increased significantly to a maximal level 4hr after the hCG stimulation and subsequently decreased. The adenylate cyclase activity was usually shown on the cytoplasmic side of surface gap junctions during the follicle maturation and ovulatory process. However, no enzyme activity was detected on the inside membrane of some annular gap junctions with bizarre forms or electronlucent contents. Collectively, present cytochemical and morphometrical results suggest that surface gap junctions are infolded in the form of annular gap junctions by the endocytotic process and degraded into the cytoplasma, in accordance with the follicle maturation and ovulation.

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Neuronal structures containing glicentin- or pancreatic glucagon-like immunoreactivity were studied in the rat brain by peroxidase anti-peroxidase immunohistochemistry. With anti-glicentin 49-69 serum R-4804, which recognized gut type glucagon but did not react with pancreatic type glucagon, immunoreactive nerve fibers and terminals were distributed in several brain regions including the hypothalamus. No immunoreactive neuronal soma was found in intact rats. Intraventricular injection of colchicine successfully revealed cell bodies with glicentin-like immunoreactivity in the lower medulla oblongata. These neuronal somata, though few in number, were mainly localized in a region between the nucleus tractus solitarius and nucleus dorsalis nervi vagi. Ventrolaterally to this region, some positive cells were also scattered up to the nucleus reticularis lateralis. The location of these glicentin-like immunoreactive cells closely resembled that of catecholamine cell groups A1 and A2. Our results strongly suggest that the rat brain contains gut type but not pancreatic type glucagon, and here a map of glicentin-like immunoreactive neuronal structures was given in detail.

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A case of pulmonary barium granuloma due to old-time aspiration of barium sulphate during contrast X-ray examination was studied using an electron probe X-ray microanalyser with a computer system. The results revealed the presence of abundant barium sulphate in situ.

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Catecholestrogen was localized in rat liver by immunocytochemical methods to study optimal fixation conditions in paraffin-embeded tissue. Rabbit anti-2-hydroxyestrone antiserum was obtained using 2-hydroxy estrone coupled with bovine serum albumin as the antigen. The most constantly positive staining for catecholestrogen was obtained with periodate-lysine paraformaldehyde (PLP) and buffered picric acid-paraformaldehyde (PAF), although other fixatives also showed staining results.

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The localization of atrial natriuretic polypeptide (ANP) in human adult and fetal hearts was investigated by an immunoperoxidase procedure using anti-α-human ANP antiserum. Light microscopically, the reaction product for ANP was observed in atrial muscle cells and was well confined within both the atrium and atrial septum with the exception of the specialized conducting system of adult heart. No prominent difference in intensity of immunostaining was observed in any part of the atrium. Intracytoplasmic immunoreaction product for ANP was finely granular and generally concentrated at paranuclear sarcoplasm. Electron immunogold stain for ANP of the human adult atrium was also carried out. Ultrastructurally, gold particles were demonstrated in atrial specific granules. Immunoreactive-ANP was also demonstrated in all atria of fetuses at 7, 11, 12, 13, 16 and 17 weeks of gestation. The distribution of the reaction products was similar to those of the adult heart, and there was a tendency of increased staining intensity for ANP with gestational age.

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Ultrastructural changes of macrophage in mouse thymus during exogenous (heterophagy) and endogenous material (autophagy) digestive process were investigated with the cytochemical demonstration of acid phosphatase (AcPase) activity. During the phagocytosis of macrophage, an apparent periodic change could be observed in the lysosomal system. According to this periodic change, we proposed a new concept of phagocytosis period. This period could be divided into a heterophagocytosis stage and an autophagocytosis stage. The main feature of the heterophagocytosis stage was that the activity of phagocytosis increased, a large number of irregularly shaped heterophagolysosomes (HPL) were formed, then many small lysosomes were formed by budding and pinching-off from the HPL. In the autophagocytosis stage, a lot of small lysosomes were wrapped by the irregular-shaped HPL. It was indicated that in the autophagocytosis stage the autophagy of macrophage was a phenomenon of self-phagocytosis of HPL.

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