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dc.contributor.authorLu, S
dc.contributor.authorMontesano, R
dc.contributor.authorZhang, M
dc.contributor.authorFeng, L
dc.contributor.authorLuo, F
dc.contributor.authorChui, S
dc.contributor.authorUmbenhauer, D
dc.contributor.authorSaffhill, Roy
dc.contributor.authorRajewsky, M
dc.date.accessioned2010-11-30T17:55:58Z
dc.date.available2010-11-30T17:55:58Z
dc.date.issued1986
dc.identifier.citationRelevance of N-nitrosamines to esophageal cancer in China. 1986, 4:51-8 J Cell Physiol Supplen
dc.identifier.issn0737-1462
dc.identifier.pmid3528183
dc.identifier.doi10.1002/jcp.1041290411
dc.identifier.urihttp://hdl.handle.net/10541/116744
dc.description.abstractStudies on the relevance of the N-nitrosamines to esophageal cancer in China are reviewed. Esophageal cancer is a complex and multifactorial problem. Although a causal association between nitrosamines exposure and esophageal cancer in China has not yet been rigorously established, exposure of Lin-Xian subjects to nitrosamines either directly or as a result of their in vivo formation has been detected in our study. Several N-nitrosamines (NDMA, NDEA, NMBzA, NPyr, NPip, and NSAR) in gastric juice collected from Lin-Xian inhabitants have been detected. A correlation was found between the lesions of esophageal epithelium and the amount of nitrosamines present. In addition, the amounts of N-nitrosamino acids (N-nitrosoproline, N-nitrosothiazolidine 4-carboxylic acid, NSAR, and nitrates) excreted in 24-hr urine of subjects in Lin-Xian were significantly higher than those in Fan-Xian, indicating a higher exposure to N-nitroso compound and their precursors of the inhabitants in the high-risk area. The effect of nitrosamines on human esophagus has been investigated at the cellular levels. The amounts of O6-MedG in DNA of esophageal or stomach mucosa of patients from Lin-Xian were higher than that from Europe (Lyon and Essen). The presence of O6-MedG in the human fetal esophagus cultured with NMBzA was also detected. These findings indicate that the elevated levels of O6-MedG in esophageal DNA could be the result of a recent exposure to N-nitroso compounds or a genetically determined reduced cellular capacity for repair of O6-MedG from DNA. The hyperplasia was induced in the esophagus of human fetus that cultured with NMBzA for 2 weeks to 2 months. The intervention studies of esophageal cancer in Lin-Xian have been pursued. Intake of moderate doses of ascorbic acids by Lin-Xian subjects effectively reduced the urinary levels of N-nitrosamino acids to those found in un-dosed subjects in the low-risk area. If N-nitroso compounds are formed in vivo and are among the causative factors of esophageal cancer in Lin-Xian, ascorbic acid appears to be effective in lowering the body burden of these carcinogenic compounds. Thus, the plan of chemoprevention is carried out in Lin-Xian.
dc.language.isoenen
dc.subjectOesophageal Canceren
dc.subjectOesophagusen
dc.subject.meshAscorbic Acid
dc.subject.meshChina
dc.subject.meshDNA
dc.subject.meshEpidemiologic Methods
dc.subject.meshEsophageal Neoplasms
dc.subject.meshEsophagus
dc.subject.meshFemale
dc.subject.meshGastric Juice
dc.subject.meshGuanine
dc.subject.meshHumans
dc.subject.meshHyperplasia
dc.subject.meshNitrosamines
dc.subject.meshPregnancy
dc.subject.meshTime Factors
dc.titleRelevance of N-nitrosamines to esophageal cancer in China.en
dc.typeArticleen
dc.contributor.departmentCancer Institute, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.en
dc.identifier.journalJournal of Cellular Physiology. Supplementen
html.description.abstractStudies on the relevance of the N-nitrosamines to esophageal cancer in China are reviewed. Esophageal cancer is a complex and multifactorial problem. Although a causal association between nitrosamines exposure and esophageal cancer in China has not yet been rigorously established, exposure of Lin-Xian subjects to nitrosamines either directly or as a result of their in vivo formation has been detected in our study. Several N-nitrosamines (NDMA, NDEA, NMBzA, NPyr, NPip, and NSAR) in gastric juice collected from Lin-Xian inhabitants have been detected. A correlation was found between the lesions of esophageal epithelium and the amount of nitrosamines present. In addition, the amounts of N-nitrosamino acids (N-nitrosoproline, N-nitrosothiazolidine 4-carboxylic acid, NSAR, and nitrates) excreted in 24-hr urine of subjects in Lin-Xian were significantly higher than those in Fan-Xian, indicating a higher exposure to N-nitroso compound and their precursors of the inhabitants in the high-risk area. The effect of nitrosamines on human esophagus has been investigated at the cellular levels. The amounts of O6-MedG in DNA of esophageal or stomach mucosa of patients from Lin-Xian were higher than that from Europe (Lyon and Essen). The presence of O6-MedG in the human fetal esophagus cultured with NMBzA was also detected. These findings indicate that the elevated levels of O6-MedG in esophageal DNA could be the result of a recent exposure to N-nitroso compounds or a genetically determined reduced cellular capacity for repair of O6-MedG from DNA. The hyperplasia was induced in the esophagus of human fetus that cultured with NMBzA for 2 weeks to 2 months. The intervention studies of esophageal cancer in Lin-Xian have been pursued. Intake of moderate doses of ascorbic acids by Lin-Xian subjects effectively reduced the urinary levels of N-nitrosamino acids to those found in un-dosed subjects in the low-risk area. If N-nitroso compounds are formed in vivo and are among the causative factors of esophageal cancer in Lin-Xian, ascorbic acid appears to be effective in lowering the body burden of these carcinogenic compounds. Thus, the plan of chemoprevention is carried out in Lin-Xian.


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