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Biomedical subjects

K Oota

Publications and source records attributed to K Oota.

36 records · Page 2Linked to original sources
PubMed1979

Neuroendocrine cells in serially passaged rat stomach cancers induced by MNNG.

Five gastric carcinomas, induced in inbred Wistar rats by oral administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) dissolved in drinking water, were successfully transplanted to isologous rats. The transplants grew to a size of 10 to 35 mm in diameter within 8 to 25 weeks of implantation. In one case, serial transplantation were maintained up to the 11th generation, with occurrence of distant metastasis in the 3rd generation. Histological histochemical, and electron microscopical comparison of the original and transplanted tumors revealed that (1) the original tumors were quite well differentiated, forming either papillary or tubular structures, whereas the transplants were more anaplastic and pleomorphic showing often solid nests; and (2) tumor cells with gastrointestinal differentiation and cells with neuroendocrine differentiation were present and evenly distributed in both the original and the serially transplanted tumors. As it is unlikely that the normal and neoplastic neuroendocrine cells are growing side-by-side with and independently of the epithelial neoplastic components in the present series of transplants, the findings strongly suggest (1) the multidirectional potency of the inbred rat stomach carcinoma cells and (2) the common neoplastic origin of the epithelial and neuroendocrine components.

Animals↗
PubMed1978

[Intracranial surgery under hemodialysis (author's transl)].

A case of pituitary adenoma operated on under hemodialysis was reported. The patient was a 43-year-old male who had been obliged to hemodialysis since April 1975 because of chronic renal failure. He was admitted in February 21, 1976 because of progressive visual symptoms. Neurological examination revealed decreased visual acuity and bitemporal hemianopsia. Radiology showed enlarged sella turcica and calcified mass in the suprasellar region. Laboratory examination disclosed severe anemia and the operation was postponed until the hematocrit improved up to 39% by blood transfusion. The operation was performed in March 17, 1976 under conventional GOF anesthesia. The tumor was covered by a calcified capsule and after nibbling off the calcified covering, the tumor was removed. Postoperative course was uneventful. Peritoneal dialysis was continued for three days immediately after operation. Urinary volume of the patient increased up to 600 ml per day after operation, probably due to the postoperative diabetes insipidus. The diabetes insipidus was rather favorable sequela in this case because the patient was released from the severe restriction of water intake.

Adenoma, Chromophobe↗
PubMed1975

Metastasis formation of Yoshida sarcoma heterotransplanted in adult golden hamsters treated with anti-hamster thymocyte serum.

Growth of Yoshida sarcoma cells heterotransplanted in adult golden hamsters treated with antithymocyte serum was investigated. Control animals were grafted with or without hydrocoritisone conditioning. In the antithymocyte serum-treated group, tumors were produced in cheek pouches and grew progressively in size until Day 21 with no sign of regression. Little host reaction was noticed histologically around the tumor grafts throughout the course. Distant metastases were revealed at autopsy in 9 of 12 animals from Day 14 of inoculation on, and all the experimental animals died by Day 23. Six of the 9 hamsters with metastases died of tumor. By means of the back-transplantation test, the metastatic tumor cells were shown to be consistent with Yoshida sarcoma cells. In hydrocortisone-treated and untreated groups, the tumor size reached a maximum on Day 21 and Day 5, respectively, and then regression followed. No metastasis was detected in either control group.

Animals↗
PubMed1975

Heterotransplantation of cell lines derived from human malignant neoplasms into golden hamsters treated with antithymocyte serum.

Thirteen cell lines of tissue culture originated from human malignant neoplasms were transplanted into cheek pouches of adult golden hamsters treated with anti-hamster thymocyte serum. In eleven cell lines, transplantation tests with 3.5 X 10(6) to 6.8 X 10(6) cells resulted in neoplastic growth within 4 weeks. In other two cell lines including one from neuroblastoma and another from Burkitt's lymphoma, the inoculum size had to be raised to 11.8 X 10(6) and 12.2 X 10(6) cells to get tumor growth, respectively. The histological appearance of those tumors was consistent with that of the individual primary neoplasms despite of their long in vitro histories. Anaplasia grading of the tumors appeared not to be correlated with the frequency of take.

Adenocarcinoma↗
PubMedDate not supplied

Localization and expression of a collecting duct water channel, aquaporin, in hydrated and dehydrated rats.

The cellular and subcellular localization and expression of a kidney collecting duct water channel, aquaporin (AQP)-CD, were examined in the kidneys of hydrated and dehydrated rats by immunostaining, Northern blot analysis, and radioimmunoassay. In hydrated rat kidneys, AQP-CD was selectively found in the collecting duct principal cells and inner medullary collecting duct cells, but not in the intercalated cells. At a light microscopic level, AQP-CD was diffusely present in a granular pattern throughout the cytoplasm of the collecting duct cells with a preferential accumulation in subapical regions. By immunoelectron microscopy, AQP-CD was frequently demonstrated along membranes of small vesicles in the subapical cytoplasm and occasionally along the basolateral membranes of these cells. However, immunolabeling was sparse on the apical membranes. In dehydrated rats, AQP-CD immunostaining was intensified in the subapical cytoplasm of the collecting duct cells, along with increases in the number and size of AQP-CD-bearing vesicles in the subapical regions and with increment of labeling along the apical membranes. The increase in the amount of AQP-CD in the collecting duct cells of dehydrated rat kidneys was quantitatively confirmed by elevation of AQP-CD at mRNA and protein levels. The AQP-CD localization is consistent with the predicted site of the antidiuretic hormone (ADH)-regulated water channel in the collecting ducts and the increase in AQP-CD at mRNA and protein levels by dehydration may account for high concentration of urine in dehydrated subjects.

Animals↗