[Inhibitory effects of hybrid liposomes on the growth of gastric tumor cells established from cotton rats].

We established cell-line (CoRa 622 G6) of gastric carcinoma using cotton rats with spontaneous malignant gastric carcinoma with hypergastrinaemia. Inhibitory effects of hybrid liposomes (HL) composed of dimyristoylphosphatidylcoline (DMPC) and polyoxyethylene (n) dodecyl ether (C(12)(EO)(n): n=21, 23, 25) on the growth of CoRa 622 G6 cells were clarified on the basis of WST-1 assay. Fusion and accumulation of HL including fluorescence probe into CoRa 622 G6 cell membrane were clarified using confocal laser microscopy and total internal reflection fluorescence microscopy.

Dedifferentiation of enterochromaffin-like cells in gastric cancer of hypergastrinemic cotton rats.

The role of enterochromaffin-like (ECL) cells in gastric carcinogenesis is not fully understood. Spontaneous tumours developing in hypergastrinemic female cotton rats have an adenocarcinoma phenotype, but numerous cells in the dysplastic mucosa as well as in the carcinomas are positive for neuroendocrine markers. In the present study of female cotton rats with 2 and 8 months' hypergastrinemia, the oxyntic mucosa of the stomach was examined histologically and immunolabelled for histidine decarboxylase (HDC) and pancreastatin, and hyperplastic and neoplastic ECL cells were evaluated by electron microscopy.

Outbreak of larval Echinococcus multilocularis infection in Japanese monkey (Macaca fuscata) in a zoo, Hokkaido: western blotting patterns in the infected monkeys.

A high prevalence of larval Echinococcus multilocularis (Em) infection was found in zoo primates in Hokkaido, Japan. In October 1997, a Japanese monkey (Macaca fuscata) died and histopathologically diagnosed as alveolar hydatidosis. Serum samples were collected from the remaining Japanese monkeys and examined for antibodies against Em by enzyme-linked immunosorbent assay and western blotting.

ECL-cell derived gastric cancer in male cotton rats dosed with the H2-blocker loxtidine.

Spontaneously hypergastrinemic cotton rats (Sigmodon hispidus) develop tumors that have the phenotype of an adenocarcinoma but most likely originate from the enterochromaffin-like (ECL) cells. Among inbred animals approximately 50% of the females, but <1% of males develop spontaneous gastric carcinomas. Gastrin is the principle carcinogen in this model, as >4 months of hypergastrinemia results in carcinoma, but a gastrin receptor antagonist prevents carcinomas.

Spontaneous ECL cell carcinomas in cotton rats: natural course and prevention by a gastrin receptor antagonist.

In our inbred strain of cotton rats (Sigmodon hispidus) 50% of the females develop spontaneous ECL cell-derived tumors in the acid-producing part of the stomach due to hypergastrinemia secondary to gastric hypoacidity. Although the mechanism behind the hypoacidity is unknown, the female cotton rat is an excellent model for studying ECL cell-related tumorigenesis. In this study we wanted to explore the malignancy potential of these tumors and the ability of a gastrin receptor antagonist (YF476) to prevent their development.