霉变食品中新亚硝胺:N-3-甲基丁基-N-1-甲基丙酮基亚硝胺

以林县粮食中常见的霉菌如白地霉、土曲霉等接种于玉米面饼上,培养数日后,加一定量亚硝酸钠,即可产生亚硝胺,其中经高分辨GC-MS证实,有N-3-甲基丁基-N-1-甲基丙酮基亚硝胺,我们又通过化学合成MAMBNA加以验证,证明化学合成的MAMBNA与霉变玉米面饼中分离的MAMBNA结构完全一致,本文对产生这种新亚硝胺的物质基础和其在食管癌高发区中的意义进行了讨论。     

致癌的亚硝胺在霉变玉米面中的形成

以林县粮食中常见的霉菌,如串珠镰刀菌、黄曲霉菌等,接种于玉米面饼,培养数日后,加一定量的亚硝酸钠,其提取物经GC-MS证实能产生DMNA,DENA与MBNA,这些致癌亚硝胺化合物能诱发动物的肝癌或食管癌.在霉变食物中,霉菌除产生毒素外,还能促进化学致癌物的形成,这为肿瘤病因学提供了新的研究领域。     

N-3-甲基丁基-N-1-甲基丙酮基亚硝胺体外恶性转化金仓鼠肺成纤维细胞的研究

一种存在于林县霉变玉米面中的新亚硝胺化合物——N-3-甲基丁基-N-1-甲基丙酮基亚硝胺(MAMBNA)已人工合成。利用新生金仓鼠肺成纤维细胞体外恶性转化模型,引入微粒体酶代谢激活系统检测了MAMBNA。实验结果,MAMBNA同已知的强化学致癌物N-甲基-N'-硝基-N-亚硝基胍和二乙基亚硝胺一样,能使体外培养的金仓鼠肺成纤维细胞发生恶性转化。证明MAMBNA是林县这一高癌地区的一种环境致癌物。本系统除可用于检测可疑环境致癌物外,尚可作为研究癌变机理的体外模型。     

MALIGNANT TRANSFORMATION OF BABY HAMSTER LUNG FIBROBLASTS INDUCED IN VITRO BY A NEW NITROSAMINE COMPOUND

A new nitrosamine compound, N-1-methylacetonyl-N-3-methylbutyl-nitrosamine (MAMB-NA), isolated from corn bread inoculated with moulds commonly occurring in Linxian County,a high incidence area for esophageal cancer in North China was tested for its potentialcarcinogenicity in vitro. Baby hamster lung fibroblasts (BHL) were treated with MAMBNAin tissue culture medium containing liver microsome preparation of Aroclor 1254 treatedrat. Cell transformation was assessed by morphological changes, loss of density-dependentinhibition and unlimited growth in vitro, chromosome changes, colony formation on softagar, growth at low serum concentration, Con A agglutinability and tumor formation afterheterotransplantation into immunosuppressed newborne rats. Like the known carcinogensN-methyl-N'-nitro-N-nitroso-guanidine and diethylnitrosamine, MAMBNA was able to causemalignant transformation of cells cultured in vitro.