魔芋葡甘露聚糖逆转大肠癌5-氟尿嘧啶耐药的作用及其机制研究

目的 探究魔芋葡甘露聚糖（konjac glucomannan,KGM）体内外逆转大肠癌5-氟尿嘧啶（5-fluorouracil, 5-FU）耐药作用及其相关机制。方法 构建HCT-8/5-FU耐药细胞株,采用MTT法验证HCT-8/5-FU细胞的耐药性以及KGM和5-FU对HCT-8/5-FU细胞的增殖抑制作用;采用CompuSyn软件分析KGM和5-FU联合用药的联合指数,评价联合效应;流式细胞术检测两药对HCT-8/5-FU细胞凋亡的影响;Western blotting检测PI3K/Akt信号通路蛋白表达情况;构建裸鼠移植瘤模型,检测KGM和5-FU体内抑瘤效果。结果 HCT-8/5-FU细胞株对5-FU的敏感性显著降低;KGM和5-FU单用均能够抑制HCT-8/5-FU细胞的增殖,两者联用能够更加有效地抑制HCT-8/5-FU细胞增殖;CompuSyn软件分析结果表明KGM和5-FU具有协同作用;KGM和5-FU联用能够显著增加HCT-8/5-FU细胞凋亡率,并抑制PI3K/Akt信号通路活性（P<0.05）;KGM和5-FU联用的抑瘤率显著高于5-FU单独使用（P<0.05）。结论 KGM能够逆转大肠癌5-FU耐药,其作用机制跟PI3K/Akt信号通路有关。     

Respiratory function and immunological status in cocoa and flour processing workers

Respiratory function and immunological status were studied in 40 cocoa and 53 flour processing workers employed as packers in a confectionry industry and in 65 unexposed control workers in the same industry. A high prevalence of chronic respiratory symptoms was recorded in exposed workers, varying from 5.0% to 30.0% in cocoa workers and from 5.7% to 28.3% in flour workers. Occupational asthma was diagnosed in 2 (5%) of the cocoa workers and in 3 (5.7%) of the flour workers. None of the control workers suffered from occupational asthma. The prevalence of almost all chronic respiratory symptoms was significantly greater in cocoa and flour workers than in control workers. There was also a high prevalence of acute symptoms that developed during the work shift, being highest for cough (cocoa: 57.5%; flour: 50.9%) and eye irritation (cocoa: 50.0%; flour: 54.7%). Significant across-shift reductions of ventilatory capacity were recorded in exposed workers, being largest for flow rates at 50% and the last 25% of the vital capacity on maximum expiratory flow-volume (MEFV) curves (FEF₅₀, FEF₇₅). The prevalence of positive skin tests for cocoa (60.2%) was significantly higher than the prevalence of positive skin tests for flour (25.8%) among the 93 exposed workers (p < 0.05). Control workers had significantly lower prevalences of positive skin tests to cocoa (4.6%) and flour (12.3%) than exposed workers (p < 0.01). Increased total serum IgE levels were found in 17.5% of cocoa and in 18.7% of flour workers; none of the control workers had increased IgE levels. Bronchoprovocation testing demonstrated significant decreases in lung function following inhalation of cocoa dust extract and flour dust in workers with respiratory symptoms and large across-shift reductions in lung function. Dust concentrations in the working environment were higher than those recommended by Croatian standards. These data suggest that workers employed in the processing of cocoa and flour may be at a high risk for the development of allergic sensitization and respiratory impairment. Am. J. Ind. Med. 33:24–32, 1998 © 1998 Wiley-Liss, Inc.     

魔芋精粉减肥的实验研究

从魔芋中提取出来的魔芋精粉是富含葡萄甘露聚糖的膳食纤维,只含很少的蛋白质和极低的能量。将出生24天的SD大鼠分为三组,均喂以高脂肪高营养饲料,第一组为对照组;第二、三组的饲料中每天分别加入1.9mg/g体重和19mg/g体重的魔芋精粉。45天后得到下列结果:1.魔芋组的体重增长低于对照组;2.对照组鼠脂肪组织的重量及脂肪细胞大于魔芋组,说明魔芋有明显的减肥作用;3.三组间血清胆固醇、甘油三酯和某些元素水平无明显差异,4.魔芋组鼠的粪湿重大于对照组;5.实验中未发现不良作用。     

魔芋精粉对五种二价金属离子的体外结合研究

本研究采用体外模拟体内胃肠道环境某些条件用透析方法研究了魔芋精粉与Ｐｂ＾２＋、Ｃｄ＾２＋、Ｆｅ＾２＋、Ｚｎ＾２＋、Ｃａ＾２＋的结合。并探讨了加热处理、ｐＨ改变及环境共存离子的竞争作用对结合的影响。结果表明，魔芋精粉与五种离子的结合具ｐＨ依赖性，ｐＨ５￣５．６时发生不同程度的结合，ｐＨ１．５时无结合，ｐＨ６．５时随离子浓度增加魔芋精粉与Ｐｂ＾２＋、Ｃｄ＾２＋的结合降低，与Ｃａ＾２＋的结合增加，与Ｚｎ     

面粉加工工艺对小麦脱氧雪腐镰刀菌烯醇的影响

目的　了解加工工艺对小麦中脱氧雪腐镰刀菌烯醇 (DON)含量影响的规律 ,探讨降低面粉中DON含量的有效方法。方法　用薄层层析法[1 ] 检测小麦在加工过程不同阶段DON含量并作出分析。结果　原麦中DON含量为 36 2 0 ppb ,经净化仍保持在 344 0 ppb。制粉过程各组分DON含量在 2 90 0～ 1 86 70ppb之间。霉变小麦DON含量高达 1 4 2～ 1 4 4 .2ppm ,外观正常小麦DON含量仅为 0 .8ppm。 结论　小麦在入磨前 ,利用风力、筛理等方法将干瘪、比重轻、易碎的赤霉病麦粒去掉 ,可使面粉中DON含量得到有效控制     

Multi-walled carbon nanotubes/nickel hydroxide composite applied as electrochemical sensor for folic acid (vitamin B9) in food samples

Folic acid (FA) acts as an essential nutrient for body functions. Several countries have already proposed a resolution for flour fortification with iron and FA; thus, of food industry concern. Therefore, a new electroanalytical method based on a composite material of functionalized MWCNTs with nickel hydroxide (f-MWCNT-Ni(OH)₂) is hereby proposed. This composite material was characterized by FT-IR, TGA, SEM and TEM techniques. An inorganic ionic silsesquioxane polymer (Si4Pic⁺Cl⁻) was used to disperse the composite and applied on the modification of a glassy carbon electrode (GCE). Linear response from 0.5–26 μmol L⁻¹ was obtained based on FA electrochemical oxidation through differential pulse voltammetry. The LoD and LoQ values obtained were 0.095 μmol L⁻¹ and 0.3 μmol L⁻¹ of FA, respectively. The GCE/f-MWCNT-Ni(OH)₂-Si4Pic⁺Cl⁻ was applied for the quantification of FA in wheat flour, fortifier, and dietary supplement. Validation was performed through a comparison with molecular absorption spectrometry, showing the accuracy of the newly proposed method.     

魔芋精粉对二甲肼诱发大鼠结肠癌的影响

用二甲肼诱发大鼠结肠癌的同时，于基础饲料中加入５％或１０％魔芋精粉，另设高脂组，观察对发癌率的影响。实验结果表明结肠癌发生率各实验组与阳性组无显著性差异，高脂组显示一定的促癌作用。本实验未观察到魔芋精粉对诱发的实验性肠癌具有抑制作用。     

面粉强化的国际经验及我国面粉强化的推动

面粉强化是国际社会广泛应用的改善营养的方法。我国是面粉生产和消费大国 ,强化面粉对我国的营养改善也将产生重要作用。本文介绍了一些国家面粉强化的经验和营养改善效果。对我国面粉消费和生产企业状况进行论述 ,并介绍了我国面粉强化工作现状和进展情况。     

血浆置换在抢救酵米面中毒的临床应用

目的　提高酵米面中毒抢救的成功率 ,减少病死率。方法　对 44例酵米面中毒在内科综合治疗基础上部分分别联合血浆置换 (PE)、血液透析、换血治疗 ;15例单纯内科综合治疗 (综合组 )。并对各种疗效进行分析和对比。结果　PE组 18例中 ,治愈 15例 ,死亡 3例 ;血透组 2例中 ,死亡 2例 ;换血组 9例中 ,治愈 5例 ,死亡 4例 ;单纯综合治疗组 15例中 ,死亡 15例。PE与综合组比效差异有高度显著性 (P <0 .0 1)。结论　在内科综合抢救治疗基础上及时配合PE治疗 ,是减少酵米面中毒病死率的重要措施。     

Respiratory symptoms and pulmonary function in flour processing workers in the baking industry

Respiratory symptoms and ventilatory capacity were studied in 63 flour processing male bakery workers in Umtata, Transkei, Southern Africa. The controls were from a bottling plant in the same city. Both groups were black Africans from the Xhosa-speaking population. The studied population was nonsmoking and no significant difference was noted in age, race, sex, or height between the groups. The exposed workers had significantly lower forced expiratory indices than the control group. Mean percent predicted values of forced expiratory volume in one second (FEV₁), forced expiratory ratio (FEV₁/FVC x 100), forced mid-expiratory flow between 25% and 75% of FVC (FMF), forced expiratory flow between the first 200 ml and 1.200 ml of FVC (FEF 200-1,200), and peak expiratory flow rate (PEF) were, respectively, 11.2%, 20.0%, 31.0%, 27.4%, and 36.1% lower in the exposed group compared with the controls. The prevalence of forced expiratory ratio less than 70% in the exposed group was 37% while in the controls it was 8%. The prevalence of PEF rate less than 5 l/s in the exposed group was 32% while in the controls it was 11%. The exposed workers reported a significantly higher prevalence of respiratory symptoms compared to the controls. The prevalence of nasal symptoms, phlegm, and cough in the exposed workers was 53.9%, 30.1%, and 25.4%, respectively. The present study demonstrated that exposure to flour dust in flour processing workers in the baking industry is associated with significantly lower pulmonary functions and a higher prevalence of respiratory symptoms, and that these workers show signs of airway obstruction, compared to workers not exposed to flour. Flour processing workers have a significant occupationally related respiratory impairment.