Biomedical subjects

M Kitajima

Publications and source records attributed to M Kitajima.

454 records · Page 26Linked to original sources

PubMedDate not supplied

Stimulation of human tumor xenograft growth by local estrogen biosynthesis in stromal cells.

BACKGROUND: Both biochemical and histochemical studies have demonstrated the expression of aromatase activity in stromal cells surrounding breast cancers, suggesting that local estrogen biosynthesis promotes the growth of these cancers. However, the role of local aromatase activity in stimulating hormone-dependent breast cancer is still controversial. MATERIALS AND METHODS: A hormone-dependent human breast carcinoma xenograft, Br-10 and human fibroblast cells obtained from a patient with benign breast disease were used in the experiments. When subcutaneously inoculated Br-10 started exponential growth in female nude mice, 10(6) fibroblast cells were injected around the tumor with or without intramuscular administration of 50 mg/kg testosterone. RESULTS: The growth of Br-10 treated with fibroblasts and testosterone was significantly enhanced in comparison with the control (p < 0.05). This stimulation by fibroblasts and testosterone was also observed in ovariectomized nude mice. Immunohistochemical staining for aromatase was observed in tumor sections containing Br-10 from mice treated with fibroblasts and testosterone, particularly around the carcinomatous glands. CONCLUSION: We conclude that estrogen produced locally by aromatase in fibroblasts can regulate the growth of hormone-dependent breast carcinoma cells.

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PubMedDate not supplied

Antitumor activity of murine monoclonal antibody NCC-ST-421 on human cancer cells by inducing apoptosis.

BACKGROUND: The murine monoclonal antibody NCC-ST-421 (ST-421) recognizes dimeric Le(a) antigen expressed on gastrointestinal cancer cells. MATERIALS AND METHODS: Direct antitumour activity of ST-421 was evaluated using dimeric Le(a) positive cell lines Colo 205, Colo 201, HT-29 and WiDr; and negative cell lines MX-1 and K562. RESULTS: While time- and concentration-dependent antitumour activity was observed against Colo 205 and Colo 201, no antitumour activity was detected against the other cell lines tested in an in vitro cytotoxicity assay. When ST-421 was administered intraperitoneally daily for 2 weeks to severe combined immunodeficient (SCID) mice transplanted with tumour xenografts, inhibition of tumour growth was observed against Colo 205, and to a lesser extent HT-29 and WiDr. Anti-asialo GM1 antibody did not block this antitumour activity, suggesting ST-421 has a direct cytotoxic effect. The degree of antitumour activity of ST-421 dependent on the grade of Le(a)-expression as detected by immunohistochemical staining. CONCLUSIONS: Flow cytometric and immunohistochemical analysis suggests the induction of apoptosis may play a key role in the direct antitumour activity of ST-421 on Colo 205 cells.

Animals↗

PubMedDate not supplied

Management of primary gastric lymphomas from a surgeon's viewpoint.

Primary gastric lymphoma is a relatively uncommon disease and controversy still exists over its management. In order to assess prognostic factors of lymphomas, we carried out a retrospective study of 28 surgically treated gastric lymphoma patients. The overall survival rate for all the patients in the study was 33% at 10 years. On univariate analysis, lymph node metastasis and depth of tumor infiltration proved to be a significant prognostic factor while size and location of tumor, sex, and method of resection was not. From our results we believe that gastric lymphoma can be regarded as a localized disease in the early stages and a curative resection can be attained when aggressive surgery is possible.

Aged↗

PubMedDate not supplied

99mTc-MIBI scintigraphy as an indicator of the chemosensitivity of anthracyclines in patients with breast cancer.

BACKGROUND: Chemoresistance of tumor cells is involved with many factors, one of which is the P-glycoprotein function to pump anthracyclines out of cells. 99mTc-MIBI accumulates in several tumors, and some of these cells wash out 99mTc-MIBI through P-glycoprotein. MATERIALS AND METHODS: We investigated if the wash-out of 99mTc-MIBI from the tumor in fifteen female patients with breast cancer could be related with the chemosensitivity of anticancer agents; doxorubicin (DOX), epirubicin (FAM), pinorubicin (PINO), mitomycin (MMC), cisplatin (CDDP), and 5-fluorouracil (5-FU), in each tumor tissues. The wash-out of 99mTc-MIBI, defined as retention index, was quantified from an early and delayed 99mTc-MIBI imaging. The chemosensitivity of the anticancer agent, and inhibition ratio, was determined in vitro assay by using surgical specimens obtained from patients who underwent 99mTc-MIBI imaging. P-glycoprotein in the surgical specimen was studied by immunohistochemical staining on its paraffin section using a monoclonal antibody. RESULTS: Inhibition ratio of anthracycline agent, DOX, FAM or PINO, was well correlated with retention index of 99mTc-MIBI with coefficient of 0.75, 0.60, or 0.62, respectively, whereas a poor relationship was observed for MMC and CDDP. The retention indices of 99mTc-MIBI were remarkably small for patients in the P-glycoprotein positive group. CONCLUSION: 99mTc-MIBI retention index quantified from its early and delayed scintigraphy is a good indicator to predict the chemosensitivity of anthracyclines in untreated breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗