title: Timing of N-methyl-N-nitrosourea administration affects gastric carcinogenesis in Mongolian gerbils infected with Helicobacter pylori.
abstract: In Mongolian gerbils, the gastric mucosa shows dramatic changes after Helicobacter pylori inoculation. The influence of the timing of N-methyl-N-nitrosourea (MNU) administration after H. pylori inoculation on gastric carcinogenesis was investigated. Ninety-two gerbils were divided into four groups. One group was given MNU at 24 weeks, and another at 1 week, after H. pylori inoculation. The other groups received only MNU. Stomachs were excised for histological examination 20 weeks after completing the MNU treatment. Carcinomas arose only in animals given MNU 1 week after H. pylori inoculation. In the relationship between H. pylori and gastric carcinogenesis, H. pylori is a promoter rather than an initiator, and other environmental factors (the timing of MNU administration) play important roles.
authors.affiliation: The First Department of Surgery, Shinshu University School of Medicine, Asahi 3-1-1, 390-8621, Matsumoto, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Maruta
authors.forename: A
authors.initials: A
authors.lastname: Sugiyama
authors.forename: K
authors.initials: K
authors.lastname: Ishida
authors.forename: T
authors.initials: T
authors.lastname: Ikeno
authors.forename: M
authors.initials: M
authors.lastname: Murakami
authors.forename: S
authors.initials: S
authors.lastname: Kawasaki
authors.forename: H
authors.initials: H
authors.lastname: Ota
authors.forename: M
authors.initials: M
authors.lastname: Tatematsu
authors.forename: T
authors.initials: T
authors.lastname: Katsuyama
mesh_terms: D000230:Adenocarcinoma / Q000209:etiology / Q000473:pathology; D000477:Alkylating Agents / Q000008:administration & dosage*; D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D005756:Gastritis / Q000382:microbiology / Q000473:pathology; D005849:Gerbillinae; D016481:Helicobacter Infections / Q000097:blood / Q000150:complications* / Q000382:microbiology; D016480:Helicobacter pylori; D007422:Intestines / Q000382:microbiology / Q000473:pathology; D008679:Metaplasia; D008770:Methylnitrosourea / Q000008:administration & dosage*; D013274:Stomach Neoplasms / Q000209:etiology* / Q000473:pathology; D013997:Time Factors
chemical_list: D000477:Alkylating Agents; D008770:Methylnitrosourea; D001973:Bromodeoxyuridine