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H Shimoda

Publications and source records attributed to H Shimoda.

66 records · Page 4Linked to original sources
PubMed1990

Dynamics of gastrin-producing cells in the rat after truncal vagotomy. Evaluation by double immunostaining for bromodeoxyuridine and little gastrin.

The mechanism of hyperplasia of gastrin-producing cells (G-cells) in the rat antral mucosa after truncal vagotomy was studied using double immunostaining for bromodeoxyuridine (BrdU) and little gastrin (G17). With single labeling of BrdU, a few G-cells (less than 1%) showed positive immunostaining for BrdU in the nucleus throughout the experimental period in both vagotomized rats and those given a sham operation. The labeled cells in both groups demonstrated a linear increase of BrdU labeling in an identical number of cells for each experimental time-point. The labeling index of the G-cells increased rapidly from day 2 to day 6 and attained a maximum level of 44.0% on day 10 in the vagotomized group after cumulative labeling. Even in this group, however, many G-cells showed no BrdU immunoreactivity throughout the experimental period. These cells did not replicate during the experimental period, but showed an intense reaction product for G17 in their cytoplasm after vagotomy. The present study indicates that the most important factor involved in G-cell hyperplasia observed after truncal vagotomy is the activation of pre-existing G-cells to synthesize and release hormone, together with the rapid maturation of progenitor cells to mature G-cells.

Animals↗
PubMed1988

Expression of Ha-ras oncogene products in human neuroblastomas and the significant correlation with a patient's prognosis.

Neuroblastomas represent a spectrum of diseases categorized by histological subtypes, age of the patient, and extent of tumor (stage) at diagnosis. In this study we analyzed Ha-ras p21 (protein with molecular weight of 21,000) expression immunohistochemically on 47 primary human neuroblastomas resected at diagnosis. The data demonstrate that the amount of the Ha-ras product correlates with a favorable prognosis (P less than 0.001) and early stages of disease at diagnosis (P less than 0.05). These findings from unmanipulated human neuroblastomas indicate that the Ha-ras gene product (p21) might play a role in the mechanism(s) controlling aggressiveness in this type of tumor in vivo and that the Ha-ras p21 detected by a simple and reproducible immunohistochemical procedure may be of clinical importance in predicting prognosis in patients with this malignancy.

Abdominal Neoplasms↗
PubMed1987

Cell type-specific expressions of c-ras gene products in the normal rat.

Expression of proteins encoded by the ras proto-oncogenes was examined immunohistochemically in formalin-fixed, paraffin-embedded tissues of the normal rat using anti-ras p21 antibodies generated against synthetic peptides. Cell type specific expressions of ras gene products were detected in distal tubules of kidney, megakaryocytes in spleen, neural cells in cerebrum, Purkinje cells in cerebellum, cells lining the pulmonary alveoli and cells in the epithelium of intestinal villi. Region specific expressions of the ras proteins were observed in spleen and thymus, where the ras proteins were detected in splenic nodules including germinal centers and thymic medulla, respectively. These findings suggest that the c-ras gene products in normal rat organs are expressed in specific cell-types within a tissue and may be associated with degree of cellular differentiation.

Animals↗
PubMed1986

Organ specific expression of ras oncoproteins during growth and development of the rat.

Expression of proteins encoded by the ras proto-oncogenes was examined in extracts from normal rat organs using anti-ras p21 antibodies generated against synthetic peptides. The highest level of ras p21 was found in brain (cerebrum) and was predominantly of c-Ha-ras origin. Levels of brain ras p21 did not vary from the newborn period of 3 months of age. Moderate levels of ras p21s were detected in lung, spleen and thymus. In contrast to the p21 in brain, these levels varied with the age of the rats and were encoded by other members of ras proto-oncogene family (Ki-ras or N-ras). This organ specific expression of different ras genes might be related to developmental control of gene expressions.

Animals↗
PubMed1981

Gradual occlusion of the portal branch with hepatic artery ligation for unresectable hepatic tumour in children.

For the surgical treatment of unresectable hepatic tumour in children we devised a method whereby the portal vein is gradually occluded. Using this new procedure, combined with ligation of the hepatic artery and intraarterial and systemic anticancer chemotherapy, there was a marked decrease in tumour size and hypertrophy of the contralateral lobe of the liver. For gradual occlusion of the portal vein we used the Ameroid constrictor, which consists of a casein derivative enclosed in a stainless steel jacket, and when applied the vessels will occlude within 7-10 days. The patients tolerated this procedure well; there was no occurrence of shock, the liver dysfunction was temporary and normal ranges were reverted to within 2-3 weeks after surgery. One patient treated in this way lived for 14 months after undergoing such surgery.

Animals↗
PubMedDate not supplied

Effects of gastrin on the histamine-secretory and proliferative activity of cultured carcinoid cells derived from the stomach of the rodent Mastomys natalensis.

The effects of gastrin on the synthesis and release of histamine and on cellular proliferation were investigated in a homotransplantable carcinoid tumor implanted in the rodent Mastomys natalensis and in cultured cells derived from the tumor. The homotransplanted tumor was immunopositive for histamine, synaptophysin and protein gene product 9.5, and its cells contained numerous secretory granules that were visualized by electron microscopy. When carcinoid cells were cultured in a medium with a high concentration of gastrin-I (10(4) pg/mL) for 7 days, large electron-dense secretory granules were characteristically observed in the cytoplasm. By contrast, only a few such granules and numerous secondary lysosomes were seen in cells that had been cultured in the same medium without gastrin-I. A high concentration of gastrin-I (10(4) pg/mL) significantly increased the release of histamine into the culture medium from the carcinoid cells compared with the control (P < 0.05). Cellular proliferation, as determined by monitoring the incorporation of [methyl-3H]-thymidine into the carcinoid cells increased significantly at lower concentrations of gastrin-I (10(2) and 10(3) pg/mL), (P < 0.05). At higher concentrations (10(4) pg/mL or more), gastrin-I had no effect on proliferation. These findings indicate that gastrin stimulates the synthesis and release of histamine by carcinoid cells, as well as their proliferation.

Animals↗
PubMedDate not supplied

Clinicopathological and immunohistochemical study of cancer arising from Barrett's esophagus.

In Japan, Barrett's esophageal cancer is a very rare disease. We examined clinicopathologically and immunohistologically 4 patients with Barrett's esophageal cancer who underwent surgical resection in our department. Barrett's esophageal mucosa was classified into 3 types for detailed observation. Specialized columnar epithelium (SCE) remained on the orifice side of carcinoma, and progression to adenocarcinoma was observed in some dysplastic glands. positive findings were detected on p53 immunohistochemical staining, and the ki-67 labeling index was higher than other types. SCE-type Barrett's esophagus may be a precancerous lesion arising prior to the development of adenocarcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Primary melanocytoma arising from the thoracic leptomeninges case.

Primary melanocytoma arising from the leptomeninges of the spinal cord is very rare. A surgical specimen of a thoracic meningeal tumor was resected from a 75-year-old woman complaining of gait disturbance was investigated. Magnetic resonance imaging and myelography showed a dumb-bell-type tumor in the subdural space at the 1st to 2nd thoracic vertebrae. The tumor was subtotally resected because of adhesion to the lamina and thoracic medulla. The localized, gelatinous black tumor showed a well-defined margin without dissemination or infiltration. The tumor had a thin capsule and was composed of solid proliferation of neoplastic melanocytes. Neither whorl formation nor foci of palisaded nuclei were observed. The neoplastic cells were of two major types: an epithelioid- or polygonal-shaped type and a spindle-shaped type, and had a large nucleus, a prominent nucleolus, coarse chromatin, and melanin-pigments in their cytoplasm. Only a few mitotic figures were observed. They were positive for HMB-45 and S-100 protein. This case was considered to be primary melanocytoma arising from the thoracic leptomeninges.

Aged↗