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Yuji Yamamoto

Publications and source records attributed to Yuji Yamamoto.

74 records · Page 5Linked to original sources
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Effects of TS-1 on peritoneal dissemination of gastric cancer in nude mice.

BACKGROUND/AIMS: We investigated the effects of TS-1 on the survival of nude mice developing peritoneal dissemination of gastric cancer. METHODOLOGY: MKN-45 cells were injected into the peritoneal cavity of nude mice and a model of peritoneal dissemination was developed. TS-1 was administered orally every day from day 1 to day 10 or day 10 to day 19. RESULTS: Survival time of these treatment groups was significantly longer than untreated controls. In a pharmacokinetic study, TS-1 was administered on day 10 and the 5-fluorouracil levels were retained and maintained for a longer time, in the ascites and tumor than in plasma. The area under the concentration curve for 5-FU in the tumor was higher, than in plasma or ascites. CONCLUSIONS: TS-1 could be effective in treating peritoneal dissemination of gastric cancer, due to the supply of 5-fluorouracil in the tumor by systemic and intraperitoneal circulation.

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Expression of MMP-7 and MT1-MMP in peritoneal dissemination of gastric cancer.

BACKGROUND/AIMS: In this study, we examined the expression of MMP-2, MMP-7, and MT1-MMP in peritoneal dissemination of gastric cancer, so as to clarify a possible role of these MMPs in developing peritoneal dissemination, using culture cells and an animal model with peritoneal dissemination. METHODOLOGY: Total RNA was extracted from tumor tissues of disseminated foci from 7 patients with gastric cancer and human gastric cancer cell lines of STSA, STKM-1, MKN-28, MKN-45, and KATOIII. Expressions of mRNA for MMP-2, MMP-7, and MT1-MMP were analyzed by reverse transcriptase-polymerase chain reaction. To examine relationships between the expression of these mRNAs and the ability to establish peritoneal dissemination, nude mice were injected into the intraperitoneal cavity with 106 cultured cells of those 5 gastric cancer cell lines. RESULTS: MMP-7 was expressed in 6 of 7 tissues (85.7%) and MT1-MMP in 2 of 7 tissues (28.6%), while MMP-2 was not detected in any of 7 tumor tissues. All 7 tumors had either MMP-7 or MT1-MMP. MMP-7 was recognized in 4 of 5 cells (80%) and MT1-MMP in 2 of 5 cells (40%), while MMP-2 was not found at all. All 5 cancer cells expressed at least one MMP mRNA. In the animal experiments, nude mice inoculated with STKM-1 or MKN-45 cells developed peritoneal dissemination, while those with other cell lines did not. MMP-7 was found both in STSA and MKN-28 (dissemination negative), and in STKM-1 and MKN-45 (dissemination positive). MT1-MMP mRNA was detected in one of two dissemination positive cell lines and in one of three dissemination negative ones. CONCLUSIONS: Our results suggested the importance of MMP-7 and MT1-MMP in the peritoneal metastases of gastric cancer, however, it has to be further dissected what role these MMPs might play in detaching of cancer cells from the gastric wall and establishing peritoneal disseminating foci.

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