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摘要：目的 建立肉及肉制品中 (EPEC) 的快检方法。
方法 以 EPEC 特异的微绒毛粘连基因 (eae gene) 和菌毛束形成编码基因 (bfp gene) 作为模板，设计两对引物对肉及肉制品中的 EPEC 进行特异性扩增。
结果 该方法特异性好，对肉及肉制品中 EPEC 的最低检出量为 10cfu/g ，检出时间为 8 ～ 17 小时。
结论 建立了可检测肉及肉制品中 EPEC 的快速、敏感、特异 PCR 方法。
关键词：两重 PCR 肉及肉制品 肠致病性大肠杆菌
中图分类号： R155 . 55 TS207 . 4 文献标识码： A
Development of methods on detection of enteropathogenic escherichia coli by double PCR in meat and meat product
Shi Yun, Li Ye - peng, Ji Rong
Institute of Disease Control and Prevention, Acadimy of Military Medical Sciences, Beijing 100039, China
Abstract ： Objective To establish a rapid method for detecting Enteropathogenic Escherichia coli EPEC) in meat and meat product. Methods Based on attaching and effacing lesion ( eaeA gene) and bundle orming pili ( bfpA gene) of EPEC, two pairs of primers were designed. Then EPEC in meat and meat product were detected by double PCR. Results The method is rapid and specific. The limit of detection is 10cfu/g in 8-17hours. Conclusion\ A simple, rapid, sensitive and specific PCR method can be established to detect EPEC in meat and meat product.
Key words:double PCR ， meat and meat product ， Enteropathogenic Escherichia coli
基金项目：国家科技部十五攻关重大项目课题 (No.2001BA 804A 03)
作者简介：史云，女，博士
1 中国疾病预防控制中心营养与食品安全所
用双标稳定同位素技术分析乳糖酶缺乏者小肠粘膜乳糖酶活性
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钟燕 黄承钰 1 阴文娅 Vonk RJ 2
四川大学华西公共卫生学院，成都 610041 1 |
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摘要：目的 应用双标稳定同位素 13 C - 乳糖 / 2 H - 葡萄糖负荷试验对乳糖酶缺乏者小肠粘膜乳糖酶活性进行定量分析。
方法 选用 43 名乳糖酶缺乏者 ( 呼气 Δ H 2 浓度 >20 μ mol/mol) 作为实验对象，根据乳糖不耐受症状记录分为乳糖吸收不良组 (LM) 和乳糖不耐受组 (LI) 。以 25g 13 C - 乳糖和 0 . 5g 2 H - 葡萄糖作为受试底物，分析受试者摄入底物之后各时 点血浆中总葡萄糖、 13 C - 葡萄糖和 2 H - 葡萄糖浓度，并计算各时点 13 C - 葡萄糖 / 2 H - 葡萄糖吸收百分率的比值，以 45min 、 60min 、 75min 三个时点所得比值的均值作为乳糖消化指数 (LDI) 来反应小肠乳糖酶活性。
结果 乳糖吸收不良组和乳糖不耐受组两组各时点血浆总葡萄糖、 13 C - 葡萄糖无显著性差异 ，乳糖吸收不良组的乳糖消化指数显著高于乳糖不耐受组 (0 . 47 ± 0 . 15 vs 0 . 34 ± 0 . 14) ；乳糖消化指数与 6h 累积 H 2 呼出量无显著性相关关系 (r=0 . 12, P=0 . 46) ；经 H 2 呼气试验结果判定为乳糖酶缺乏的个体，经 13 C - 乳糖 / 2 H - 葡萄糖负 荷试验分析显示小肠粘膜仍存在一定乳糖酶活性。结论 采用双标稳定同位素 13 C - 乳糖 / 2 H - 葡萄糖负荷试验可以准确、灵敏 地定量分析小肠粘膜乳糖酶活性，同时可以计算体内乳糖消化量。
关键词：乳糖酶缺乏 稳定同位素 13 C - 乳糖 / 2 H - 葡萄糖 负荷试验
中图分类号： Q533 . 3 Q591 . 4
文献标识码： A
Analysis of lactase activities of small intestine mucous membrane by double labeled stable isotope technique in subjects with lactase deficiency
Zhong Yan, Huang Cheng - yu, Yin Wen - ya, Vonk RJ
Department Huaxi School of Public Health, Sichuan University , Chengdu 610041, China
Abstract ： Objective Low lactase activity in small intestine mucosa is the main reason for the occurrence of lactose malabsorption (LM) and lactose intolerance (LI). It would be the basis for the research on LM and LI to find an accurate method to analyze the activity of lactase. Mehtods In this study, 43 volunteers were selected and divided into LM and LI group according to the results of H 2 breath test and symptoms record. Twenty five grams of 13 C - lactose and 0 . 5g 2 H - glucose in 250ml solution were consumed by all the volunteers. The concentration of total plasma glucose, 13 C - glucose and 2 H - glucose were measured, the ratio of ［ 13 C - glucose ］ / ［ 2 H - glucose ］ and lactose digestion index (LDI)were calculated which could reflect the lactase activities in the mucous membrane of small intestine. Results It was found that there was no significant difference in the concentration of total glucose and 13 C - glucose, while the LDI in LM group (0 . 47 ± 0 . 15) was significantly higher than LI group (0 . 34 ± 0.14). There was no significant relationship between LDI and 6h cumulative breath H 2 amount (r=0 . 12, P=0 . 46). The 13 C - lactose/ 2 H-glucose challenged test showed there was still residual lactase activity in small intestine.Conclusion It was concluded that 13 C - lactose/ 2 H - glucosetest can accurately and sensitively determine the lactase activity on small intestinal mucous membrane and digestible lactose amount.
Key words:lactose deficiency, stable isotopes, 13 C - lactose/ 2 H - glucose challenged test
基金项目：国家自然科学基金资助项目 (No. 30271126)
作者简介：钟燕，女，博士，现为第二军医大学长海医院临床营 养 博士后
1 通讯作者
2 Groningen 大学，荷兰
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维生素 A 和锌联合在体外诱导人外周血单核细胞 DNA 损伤的研究
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李婷欣 李云 1 鹿子龙
四川大学华西公共卫生学院，成都 610041 |
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摘要：目的 通过碱性单细胞电泳凝胶技术和流式细胞术，研究维生素 A 和锌联合在体外诱导人的外周血单核细胞 (PBMC)DNA 的损伤。
方法 分离健康人 PBMC 在体外培养，分别加入不同剂量的维生素 A 和锌改变培养基环境，通过单细胞电泳凝胶技术和流式细胞术，分别检测各个剂量组 PBMC 的细胞凋亡率与 DNA 断裂情况。结果 体外培养时补充适量的锌和维生素 A 尚未使 PBMC 凋亡率增加，没有加重 DNA 损伤，但同时补充过量的锌和维生素 A 就会引起 PBMC 的广泛凋亡和严重的 DNA 损伤（ P<0 . 05 ），且比由于维生素 A 或锌单独过量引起的损伤更严重。当维生素 A 过量时，补充适量锌对已损伤的细胞有一定的修复作用，但可能会扩大受损的细胞范围；当锌过量时，补充适量维生素 A 对正常细胞有一定的保护作用，但可能会加剧已受损细胞的损伤程度。
结论 在体外试验中，过量的补充维生素 A 和锌可能会造成人的 PBMC 的 DNA 单链严重损伤，具体机理尚须进一步研究。
关键词：维生素 A 锌 单核细胞 DNA 损伤 彗星试验 流式细胞术 细胞凋亡
中图分类号： Q562 Q581 R151 . 2 文献标识码： A
Combination effects of vitamin A and zinc on human's
PMBC DNA damage in vitro
Li Ting - xin, Li Yun,Lu Zi - long
West China School of Public Health, Sichuan University , Chengdu 610041, China
Abstract ： Objective To study the combination effects of vitamin A (Vit.A) and zinc on human's PBMC DNA damage in vitro. Methods The PBMC from healthy volunteer was purification and cultured in the basic culture medium with Vit.A of 10 -4 , 10 -5 and 10 -6 mol/L, or/and with Zn of 10 -6 , 10 -5 , 10 -4 and 10-3mol/L. The basic culture medium with K 2 Cr 2 O 7 of 1mmol/L was the male control. The damage of PBMC DNA was respectively examined by SCGE and the image analyzer measured the comet tail rate and length. The apoptosis of each group PBMC was detected by FCM. Results The overdose supplement of zinc and Vit.A can damage the PBMC DNA in vitro culture (P<0 . 01), while the suitable supplement doesn't find. When the Vit.A supplement has been excessive, giving suitable zinc could repair the damage of DNA, but would expand the injured cell. While when the zinc supplement has been excessive, giving suitable Vit.A could protect the healthy cells, but would aggravate the damage degree of injured cell. Conclusion In vitro culture, the overdose Vit.A and zinc supplement could damage the human's PBMC DNA significantly. This need more researches to provide.
Key words:vitamin A, zinc, PBMC, DNA damage, SCGE, apoptosis, FCM
基金项目：国家自然科学青年基金资助 (No.39600122)
作者简介：李婷欣，女，硕士研究生
1 通讯作者 |
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