| Project/Area Number |
60480309
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Digestive surgery
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| Research Institution | Jichi Medical School |
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Principal Investigator |
MIYATA Michio Department of Surgery, Jichi Medical School, Assist. Professor, 医学部, 助教授 (90048976)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Yukio Department of Gastroentrology, Jichi Medical School , Reader, 医学部, 助手 (60158475)
SAKAI Hideaki Department of Gastroenterology, Jichi Medical School, Assist. Professor (Resiqna, 医学部, 助教授 (10112624)
HIROTA Norio Department of Pathology, Jichi Medical School, Assist. Proffesor, 医学部, 助教授 (20041361)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1986: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1985: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Keywords | Hyperqastrinemia / Colonic Mucosa / Trophic effect / 結腸癌の発生 |
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| Research Abstract |
Trophic effect of gastrin on both colonic and gastric mucosa was firstly studied, and then we tried to elucidate whether or not the chronic hypergastrinemia enhances the development of colorectal cancer induced by N-methyl-N-nitrosourea(MNU) in rat. MNU was a strong direct-acting carcinogen for the rat stomach. We already found that oral administration of 200ppm MNU selectively induced high incidence of glandular stomach in rat. In the present study, MNU was applied for the development of colorectal cancer. Hypergastrinemia was induced by either trucal vagotomy ordaily injection of gastrin releasing peptide (GRP), G34 and pentagastrin.
Results(1): It was demonstrated by the immunocytochemical technique using anti-bromodeoxy-uridine monoclonal antibody that DNA synthesis was increased in the colonic mucosa of the rats with chronic hypergastrinemia.
(2) Colorectal cancer: Two series of experiments about the effect of hypergastrinemia induced by several methods above mentioned on the chemical induction of colorectal cancer in the rat.
1) One hundred and twenty male Fischer rats, weighting 150-180g, were intrarectally given NMU, disolved in distilled water, 3 times weekly for 5 weeks. MNU were given at a dose of 2mg/rat. In this experiment, multiple colorectal cancers developed 20 weeks after the cessation of intrarectal injections in almost all rats in both groups of hypergastrinemia and normogastrinemia. Therefore, no significant effect of hypergastrinemia on the development of cancer was proved.
2) MNU were given at a dose of 1mg/rat for the same duration as in the first group. In this experiment, no caner developed in any rat of both groups at the end of experiment.
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