enng and Carcinoma--Squamous-Cell

In order to establish an effective method to induce selectively experimental dog esophageal carcinoma, we compared the restricted oral administration of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) with projecting spout with the ad libitum oral administration of it. Five dogs were given a solution of ENNG at a concentration of 50mg/l with restricted oral administration with projecting spout for 52 weeks. In all of them, elevated type of esophageal lesions were endoscopically observed soon after the cessation of the ENNG administration. Histological examination revealed that besides the multiple squamous cell carcinomas of the esophagus, various degrees of dysplasias were seen. Two dogs had metastasizes to the regional lymph nodes and one dog had metastatic lesions in the lung. Gastric carcinomas were also seen in four dogs. Another five dogs were given ad libitum the same concentration of ENNG solution. Gastric carcinomas were induced in four dogs, but esophageal carcinomas were seen in small lesions in two dogs. The restricted oral administration of ENNG with projecting spout is a reliable method for the selective induction of esophageal carcinoma in dog.

Topics: Administration, Oral; Animals; Carcinogens; Carcinoma, Squamous Cell; Dogs; Esophageal Neoplasms; Female; Male; Methylnitronitrosoguanidine; Papilloma; Stomach Neoplasms

Topics: Animals; Carcinoma, Squamous Cell; Intubation, Gastrointestinal; Methylnitronitrosoguanidine; Mice; Papilloma; Stomach Neoplasms

Topics: Adenocarcinoma; Animals; Carcinoma, Squamous Cell; Dogs; Dose-Response Relationship, Drug; Esophageal Neoplasms; Male; Methylnitronitrosoguanidine; Stomach Neoplasms

In order to obtain a reliable experimental model simulating human esophageal cancer, endoscopic and histopathological studies were undertaken in the esophageal cancer produced in the beagle dog. Thirty-seven dogs had been given a solution of N-Ethyl-N'-nitro-N-nitrosoguanidine (ENNG) at a concentration of 150 micrograms/ml for 3-9 months. Follow-up studies included serial endoscopy and biopsy, and almost all animals were eventually sacrificed for histological examination. The results were as follows: Squamous cell carcinoma was observed in 5 out of 22 female dogs, while none in male dogs at all. For the induction of squamous cell carcinoma in the esophagus, administration in the condition of 150 micrograms/ml (75mg/day) for 6-9 months was most suitable. Almost all of esophageal lesions were protruding and well-differentiated squamous cell carcinoma with invasion of the submucosa. The stages of hyperplasia, dysplasia and squamous cell carcinoma in the esophagus were chronologically followed. Carcinoma had been observed in the stomach about 4 months prior to the appearance of esophageal carcinoma. This experimental model was proved to be useful for studies on histogenesis of human esophageal cancer both light and electron microscopically.

Topics: Animals; Carcinoma, Squamous Cell; Dogs; Esophageal Neoplasms; Female; Male; Methylnitronitrosoguanidine; Microscopy, Electron; Sex Factors; Stomach Neoplasms

Topics: Animals; Carcinogens; Carcinoma, Squamous Cell; Dogs; Epithelium; Esophageal Neoplasms; Male; Methylnitronitrosoguanidine; Neoplasms, Experimental

Topics: Animals; Carcinoma, Squamous Cell; Dogs; Esophageal Neoplasms; Male; Methylnitronitrosoguanidine

Experimental colonic carcinoma in a dog was induced by anal insertion of an N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) suppository (each cone containing 50 mg of ENNG) for 17 months. The dog was autopsied 20 months after the initiation insertion of the suppository. Grossly, the colonic wall from the anus of the 10-cm oral side of the colon was thickened, and there was an infiltrating tumor with shallow depressions in the rough mucosa. The lymph node around this portion were enlarged, and white spots were found in the liver and redness in the lungs. Histological examination of the colon revealed a variety of pathologic features, e.g., undifferentiated carcinoma, squamous cell carcinoma and malignant melanoma in the region adjacent to the anus. Well and moderately differentiated adenocarcinomas involving the proper muscle layer were found in a region oral to these tumors and were accompanied by marked invasion of the blood vessels and lymphatic permeation. There were metastases to the liver, lungs and lymph nodes which corresponded to the gross findings, and also metastases to renal glomeruli. A well differentiated adenocarcinoma and signet ring cell carcinoma were evident in the gastric mucosa. This experimental model should be useful for studies related to colonic carcinoma in humans.

Topics: Adenocarcinoma; Animals; Carcinogens; Carcinoma; Carcinoma, Squamous Cell; Colon; Colonic Neoplasms; Dogs; Female; Melanoma; Methylnitronitrosoguanidine; Neoplasms, Experimental; Stomach; Stomach Neoplasms; Suppositories

Early changes in the esophageal mucosa of dogs induced by N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) were studied. Seven one-year-old beagle dogs were given a solution of 250 micrograms ENNG/ml to drink ad libitum for 4 months. Three different kinds of lesions (10 erosive carcinomas, 4 slightly elevated microcarcinomas and 19 leukoplakias) were recognized. These three kinds of lesions were not located adjacent to one another, and were surrounded by almost normal stratified squamous epithelium. The foci of the carcinomas revealed an abrupt transition to normal epithelium and were considered to have arisen abruptly from normal esophageal epithelium. The histogenesis of squamous cell carcinomas of the esophagus in dogs may differ from that in man.

Topics: Animals; Carcinoma; Carcinoma, Squamous Cell; Dogs; Esophageal Neoplasms; Leukoplakia; Male; Methylnitronitrosoguanidine; Neoplasms, Experimental