龙须菜藻红蛋白对Hela细胞增殖抑制及其机制的研究

目的:探讨龙须菜藻红蛋白(PE)对人宫颈癌细胞Hela体外的抑制作用及其作用机制。方法:采用MTT法检测不同浓度的藻红蛋白对Hela细胞增殖抑制效果。流式细胞仪和Annexin V-FITC/PI双荧光染色法观察藻红蛋白对Hela细胞周期及细胞凋亡的影响。结果:PE可显著抑制Hela细胞的生长,并呈剂量-效应关系(p<0.01,r=0.84),剂量为20μg/ml,作用48h,其抑制率达70.88%,其48h的IC50值为4.12μg/ml。PE可阻滞Hela细胞从G2/M期进入S期,诱导细胞凋亡。结论:PE对Hela细胞有较强的抑制作用,其作用机制部分与诱导Hela细胞调亡有关。     

Modulation of immune function by milk fat globule membrane isolates

The nutritional value and characterization of minor milk components on mammalian immune function are not fully understood. The aim of this research was to test the ability of a milk fat globule membrane (MFGM) isolate to modulate murine immune function in vitro, by studying its effects on splenocyte proliferation, apoptosis, and cytokine production. Proliferation of spleen cells was not affected by the MFGM isolate; however, in the presence of polyclonal activators, the MFGM isolate suppressed cell proliferation. Results obtained by flow cytometry did not support programmed cell death as the cause of the MFGM immune-modulating capacity. A mode of suppression on the splenocyte activation process was suggested from a marked decrease in the production of IFN-γ and tumor necrosis factor-α cytokines, typical indicators of immune cell activation. The effect of MFGM on IL-4 secretion was significantly less than that for the other 2 cytokines. The activity exerted by the MFGM over concanavalin A-stimulated cells differed from that observed in cells treated with lipopolysaccharide, suggesting a different mode of action depending on the activator used. These results indicate the potential of MFGM extracts as functional ingredients with bioactive modulating capacity.     

Sensitive determination of parabens in soy sauces by capillary zone electrophoresis with amperometric detection

A high-performance capillary zone electrophoresis with amperometric detection (CZE-AD) method has been developed for the separation and sensitive determination of the preservatives methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) in soy sauce samples. The effects of several factors such as the pH and concentration of running buffer, the separation voltage, the applied potential and the injection time on CZE-AD were investigated. Under the optimum conditions, four preservatives can be well separated within 16 min at the separation voltage of 16 kV in a 80 mmol/L borax running buffer (pH 9.94), and adequate extraction was obtained with ethanol for the determination of the above four parabens. Satisfactory recovery (95.0–102.0%), repeatability of the peak current (≤2.4%) and migration time (≤0.5%) of four analytes, as well as detection limits (5.7 × 10⁻⁸–4.4 × 10⁻⁸ g/mL) for the method, were achieved. This proposed procedure has been successfully used for the analysis of paraben preservatives in soy sauce samples, and the content of EP was from 0.08 to 0.14 mg/mL in the tested samples.     

Preliminary evaluation of the genotoxic potential of a hydrophilic polymer with three preservation systems

This study compared the genotoxic potential of a polymeric associative thickener used in topically applied emulsions preserved with three different preservative systems. The method used for the assessment of genotoxicity is the in vitro micronucleus test [Organization for Economic Cooperation and Development (OECD) guideline number 487]. When changing an additive such as a preservation system in a raw material, it is crucial to re-evaluate its toxicity potential because this change may significantly alter its properties. This study shows that at the levels tested neither of the systems evaluated demonstrated any cytotoxic or genotoxic effects. Skin exposure must take into consideration factors such as duration, skin condition and metabolism, but most importantly concentration. Although preservatives can be toxic at high concentrations, they are usually safe at the concentrations used in cosmetic raw materials and formulations. If used to preserve raw materials, they undergo further dilution when added to the formulation.     

In vitro skin permeation and retention of parabens from cosmetic formulations

Parabens are antimicrobial agents widely used in foods, cosmetics and pharmaceutical products. Although non-mutagenic, non-teratogenic and non-carcinogenic, parabens can induce allergic contact dermatitis and posses estrogenic activity. The aim of this work was to assess the skin permeation and retention of methyl- (MP), ethyl- (EP) and propyl- (PP) paraben from three commercial cosmetic creams. The results obtained indicate that parabens are capable of permeating through and accumulating in the skin. The extent of penetration depends more on paraben characteristics (solubility, lipophilicity) than on the composition of the formulation. In particular, the percentage permeated across the skin was independent of the composition of the cream used and decreased in the order MP, EP and PP, in accordance with decreasing solubility. After 8 h of contact with the skin, 60% of MP, 40% of EP and 20% of PP were found across the skin. Concerning skin retention, the percentage remaining in the skin after 8 h depends on both paraben characteristics and on the composition of the formulation used. In conclusion, it appears that only the type of paraben, in particular its water solubility, affects skin penetration whereas the composition of the emulsion, which influences skin retention, plays a secondary role. Finally, excised rabbit ear skin can be considered as a good model for human skin for in vitro experiments.     

细胞毒理学在食品领域中的应用

细胞毒理学是研究外源性物质对生命细胞损伤作用规律及其机制的一门毒理学分支学科,它可以用于食品安全毒理学的评价、食品中有害物质的毒作用机理研究、食品加工生产中有毒有害物质的检测、功能性食品中功效成分的活性研究等。细胞毒理学的研究方法有多种,用于探讨外源物对细胞的不同作用,包括对细胞的活性影响和遗传学影响、造成细胞形态学变化以及细胞凋亡检测。目前在食品领域较广泛应用的细胞毒理学方法有MTT比色实验、细胞DNA合成测定法、彗星电泳法、Western blot法、流式细胞术测定法、NRU染色法、免疫细胞化学染色技术等。     

Simultaneous determination of nine kinds of preservatives in foods by HPLC

A simple and rapid HPLC method was developed for the simultaneous determination of nine kinds of preservatives, benzoic acid (BA), sorbic acid (SOA), dehydroacetic acid (DHA), methyl p-hydroxybenzoate (PHBA-Me), ethyl p-hydroxybenzoate (PHBA-Et), isopropyl p-hydroxybenzoate (PHBA-isoPu), propyl p-hydroxybenzoate (PHBA-Pu), isobutyl p-hydroxybenzoate (PHBA-isoBu) and butyl p-hydroxybenzoate (PHBA-Bu), in foods. For solid foods, the preservatives were extracted with methanol. After addition of 5 mmol/L citrate buffer to the extract, the extract solution was cleaned up on an Oasis HLB cartridge. The cartridge was washed with 5 mmol/L citrate buffer and methanol-5 mmol/L citrate buffer (4:6). Then, nine kinds of preservatives were eluted with methanol. The eluent was used for BA, SOA and DHA determination by HPLC. Furthermore, a part of the eluent was cleaned up on a Bond Elut PSA cartridge for p-hydroxybenzoate esters determination by HPLC. Liquid foods were cleaned up after addition of 5 mmol/L citrate buffer without the extraction process, and the subsequent procedure was the same as for solid foods. The recoveries of p-hydroxybenzoate esters from ten kinds of foods fortified at levels of 0.01 and 0.10 g/kg each were 91.5 to 107.4%, and those of BA, SOA and DHA were 76.4 to 104.8%. The quantitation limits of the preservatives in foods were 0.005 g/kg. (Received March 20, 2006)     

Vitamin C induces apoptosis in AGS cells by down-regulation of 14-3-3σ via a mitochondrial dependent pathway

Ascorbic acid (vitamin C) is an essential component of most living cells. Apart from antioxidant activity, it has been reported to inhibit cancer cell growth in vitro in human cancer cells. However, the cellular mechanism underlying anticancer activity has not been fully elucidated. In this study, vitamin C showed a cytotoxic effect on human gastric cancer cell line AGS (LD50 300μg/ml). Further, flow cytometry analysis showed that vitamin C increased the sub-G1 (apoptosis) population and apoptosis confirmed by fluorescein isothiocyanate-Annexin V double staining in AGS cells. Moreover, specific immuno-blotting revealed the expression of the phosphorylated form of Bad (S136), 14-3-3σ, pro-caspases-3, -6, -8, and-9 protein levels were significantly decreased and Bax/Bcl-xL ratio was increased in a dose-dependent manner. Also, wound healing assay results showed that vitamin C inhibited AGS cell proliferation. These findings suggest that vitamin C induces apoptosis and might be a potential therapeutic agent for gastric cancer.     

红枣色素对H_2O_2诱导血管内皮细胞损伤的保护作用

探讨红枣色素对H_2O_2诱导人血管内皮细胞(human umbilical vein endothelial cells,HUVECs)损伤的保护作用。体外培养HUVECs,随机分为6组:空白对照组、H_2O_2损伤组、红枣色素低、中、高剂量组(50、150、250 mg/L红枣色素)和阳性对照组(50μmol/L VE),采用显微镜观察细胞形态,四甲基偶氮盐法检测细胞增殖活力,试剂盒法测定乳酸脱氢酶(lactate dehydrogense,LDH)活性,流式细胞仪检测细胞凋亡率和线粒体膜电位水平,透射电子显微镜观察细胞超微结构。结果表明,红枣色素可保护H_2O_2对HUVECs的损伤作用,能明显改善受损细胞形态、超微结构,显著降低细胞增殖抑制率、LDH活性、细胞凋亡率,明显提高线粒体膜电位水平(P0.05),且存在明显的剂量依赖关系。由此推断,红枣色素对氧化应激诱导血管内皮细胞损伤具有一定的保护作用,其机制可能与其抗氧化、抑制细胞凋亡和维持线粒体膜电位有关。     

双组分纤维熔喷非织造布及其潜在应用

熔喷法是全球范围内一种最通用和成本可行的能够大量地、有效地用热塑性树脂一步法制造微纤维非织造布的方法。在最近几年中 ,人们已逐渐关注研制双组分熔喷非织造布。基础研究工作已在纺织品与非织造布研制中心借助于自 1999年 3月安装的Reicofil双组分熔喷非织造布生产线上得以完成。试验了各种成分的热塑性树脂及其双组分复合的熔喷非织造布产品 ,包括单组分聚丙烯 (PP)、聚乙烯 (PE)、聚对苯二甲酸乙二醇酯 (PET)、聚对苯二甲酸丁二醇酯 (PBT)、聚酰胺 (PA)、聚对苯二甲酸丙二醇酯 (PTT) ,以及双组分PP/PE、PET/PE、PET/PP、PA6 /PP、PBT/PP、PTT/PP ,两种组分的比率为 2 5 /75、5 0 /5 0、75 /2 5。本文介绍了双组分熔喷非织造布的纤维结构与性能 ,还讨论了新型的并列型双组分熔喷非织造布的独特性能     

Preservative systems containing essential oils in cosmetic products

The aim of this study was to evaluate the antimicrobial activity of selected essential oils ( Laurus nobilis , Eucalyptus globulus and Salvia officinalis ), both alone and in combination, in cosmetic preparations characterized by an increasing risk of microbial contamination, i.e. an O/W skin cream, a hydrogel and a non-alcoholic hydrolyte. Their potential synergistic effect in combination with the usual cosmetic preservatives at low concentrations (up to 200-fold less than usual) was also investigated.     

坛紫菜多酚抗氧化及抑制UVB致HSF细胞氧化损伤作用

从坛紫菜中提取分离制备多酚组分,通过1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力、抑制β-胡萝卜素褪色能力和铁还原能力分析法评价坛紫菜多酚的体外抗氧化作用;以紫外线B(ultraviolet radiation B,UVB)致人表皮成纤维细胞(human skin fibroblast cells,HSFs)损伤模型评价坛紫菜多酚抑制紫外损伤表皮作用,考察其用于防护紫外损伤领域的可行性。体外实验结果显示,坛紫菜多酚具有较强的抗氧化作用,其DPPH自由基清除能力与同等质量浓度的二丁基羟基甲苯(butylated hydroxytoluene,BHT)相当;但抑制β-胡萝卜素亚油酸体系褪色能力和铁还原能力弱于同等质量浓度的BHT。细胞实验结果显示,坛紫菜多酚能有效降低UVB辐照所致HSFs的乳酸脱氢酶活力,维护细胞膜的完整性;降低受损细胞的活性氧类水平,增加超氧化物歧化酶、谷胱甘肽过氧化物酶活性,从而降低细胞的氧化应激状态,提升内皮细胞的抵抗氧化应激的能力,显著抑制HSFs凋亡水平。坛紫菜多酚能在细胞水平有效保护HSFs免受UVB的氧化损伤,表明紫菜多酚具有用于紫外损伤防护领域的潜力。     

Rigid Polyurethane Foam Prepared from Extruded Starch-Derived Glycol Glucosides as Chemical Intermediates

Starch-derived glycol glucosides were prepared by a continuous, twin-screw extrusion process; reacted with propylene oxide; and evaluated as the polyether polyol (PP) in rigid polyurethane (RPU) foam. Cornstarch with 10% moisture, ethylene glycol (EG), and sulfuric acid as the catalyst were reacted at 160°C in the extruder, using 4 moles EG/mole starch anhydroglucose unit (AGU). After removing unreacted EG from the extrudate by vacuum distillation, the crude mixture of products, which contained at least 85% anomeric glucosides, was reacted with propylene oxide to form the PP with a hydroxyl number of 470. The PP was then deionized and reacted with a polymeric diisocyanate, using a conventional type of formulation and pour-in-place procedure. The same formulation and procedure were used to prepare RPU foam from a commercial methyl glucoside PP (hydroxyl number 443) for comparison. The insulating capacity, compressive strength, and dimensional stability properties of the foam with the experimental PP were at least as good as the foam with the commercial PP. This study demonstrates, for the first time, that the starch-derived glycol glucosides prepared by reactive extrusion processing are suitable chemical intermediates for the preparation of RPU foams with good properties. Also the study suggests that other types of starch-derived glucosides could be prepared by reactive extrusion processing for potential uses in foams, alkyd resins, surfactants and other products.     

Low-level efficacy of cosmetic preservatives

Preservation using combinations of preservatives has several advantages. This study shows that the concentration of some of the most frequently used allergenic preservatives can be markedly lowered when they are combined with phenoxyethanol. The antimicrobial efficacy of cosmetic preservatives and known allergens of various potency [diazolidinyl urea, methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), methylisothiazolinone (MI) and phenoxyethanol] was tested alone and in various combinations of two or three preservatives together. The preservatives were tested for minimum inhibitory concentration (MIC) values and possible synergy using fractional inhibitory concentration. MCI/MI was the only preservative showing low‐level MIC against all four tested microorganisms: Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Different combinations of the preservatives indicated additive effects against the microorganisms. No combination of preservatives showed any inhibitory action on each other. Challenge tests with different concentrations and combinations were performed in a cosmetic cream. Diazolidinyl urea and MCI/MI alone were ineffective against C. albicans in a challenge test at concentrations up to 16 times higher than the observed MIC values. When combining phenoxyethanol with either one of the allergenic preservatives diazolidinyl urea, MCI/MI or MI, the cosmetic cream was adequately preserved at concentrations well below the preservatives’ MIC values as well as 10–20 times below the maximum permitted concentrations. By using combinations of preservatives, effective preservation can be achieved with lower concentrations of allergenic preservatives.     

姜黄素对H2O2诱导血小板凋亡的抑制作用及分子机制

目的：血小板凋亡在心血管疾病发生发展过程中发挥重要作用，姜黄素（curcumin，Cur）是存在于姜科植物根茎中的一种多酚类化合物，具有多种生物学活性，但是Cur对血小板凋亡是否具有调控作用尚鲜见报道，本研究通过体外实验探讨Cur对H2O2诱导血小板凋亡的影响及其潜在的机制。方法：用不同浓度（0、1、10、100 μmol/L）的Cur与健康人纯化血小板在体外共同孵育30 min，然后加入H2O2（100 μmol/L）干预血小板60 min，用流式细胞术检测血小板磷脂酰丝氨酸的暴露水平和线粒体膜电位（ΔΨm）去极化水平；用酶联免疫吸附法测定血小板凋亡蛋白Caspase-3和Caspase-9活化水平、胞内总活性氧以及超氧化物生成水平；用Western blot蛋白免疫印迹法检测血小板促凋亡蛋白Bax、Bak和细胞色素c的表达水平。结果：与对照组相比，10、100 μmol/L Cur显著抑制H2O2诱导的血小板磷脂酰丝氨酸暴露和ΔΨm去极化（P＜0.05）；同时，Western blot结果显示，Cur能显著降低H2O2诱导的血小板促凋亡蛋白Bax、Bak和细胞色素c的表达水平的升高（P＜0.05）；酶联免疫吸附测定结果表明，H2O2诱导的血小板Caspase-3和Caspase-9的活化可被10、100 μmol/L Cur显著抑制（P＜0.05）；此外，H2O2处理时，血小板内总活性氧水平和超氧化物水平显著上调，Cur干预可显著抑制胞内总活性氧和超氧化物生成（P＜0.05）。结论：Cur具有显著抑制H2O2诱导的血小板凋亡的作用。     

Chewing activity,saliva production,and ruminal pH of primiparous and multiparous lactating dairy cows

Four multiparous (MP) and four primiparous (PP) ruminally cannulated lactating Holstein cows were used in a double 4 x 4 Latin square design to study the chewing behavior, saliva production, and ruminal pH of cows in the first or subsequent lactation. Cows were fed one of four diets; three total mixed rations containing 40, 50, or 60% silage (DM basis), and a separate ingredient diet containing 50% concentrate. Dry matter intake was higher for MP cows than for PP cows (19.2 vs. 17.1 kg/d) but not as a percentage of body weight (2.97 +/- 0.06%). Multiparous cows spent more time eating than PP cows (260 vs. 213 min/d, respectively), even after adjustment for dry matter intake (13.8 vs. 12.4 min/kg DM). Multiparous cows also spent more time ruminating per day than PP cows (560 vs. 508 min/d, respectively). Eating salivation rate was not affected by parity, but resting salivation rate was higher for MP cows than for PP. Although MP cows spent more time chewing than PP cows, total daily saliva production was only numerically higher for MP cows because the increase in saliva produced during chewing was accompanied by a decrease in saliva produced during resting. Furthermore, pH profiles tended to be lower for MP cows than for PP cows. Multiparous cows may have a greater risk of incurring acidosis than PP cows because increased salivary secretion associated with increased chewing may not sufficiently compensate the increment of fermentation acids produced in the rumen due to high feed intake.     

乳酸菌细菌素抗菌潜力挖掘研究进展

乳酸菌产生的主要抗菌防腐物质是有机酸,但在乳酸菌代谢产物中发现了细菌素等其它抗菌物质,其中有的细菌素甚至具有强烈的抗真菌能力。世界范围内启动的乳酸菌基因组计划创造了巨大的生物信息流。乳酸菌基因组蕴含的生物信息将对研究乳酸菌细菌素的合成代谢途径,功能基因挖掘以及新型抗菌剂的开发搭建信息平台。结合乳酸菌细菌素的最新研究进展,讨论利用乳酸菌基因组探索乳酸菌的抗菌潜力及其作为生物防腐剂在食品保藏中的应用前景。     

地参游离酚对CCl4所致肝细胞损伤细胞凋亡、细胞周期及炎症因子的影响

通过体外实验,研究地参游离酚对CCl₄所致肝细胞损伤细胞凋亡、细胞周期及炎症因子的影响。采用流式细胞术分析细胞凋亡及细胞周期的分布,采用试剂盒测定肿瘤坏死因子α（TNF-α）、白介素8（IL-8）的含量和天冬氨酸半胱氨酸蛋白酶3（Caspase-3）活化程度,同时采用免疫组化检测环氧化酶-2（COX-2）、白介素6（IL-6）和诱导型一氧化氮合酶（iNOS）的蛋白表达水平。结果表明,与模型组相比,地参游离酚能显著降低CCl₄引起的细胞凋亡,影响细胞周期的分布,能显著降低炎症因子TNF-α、IL-8的含量并阻滞Caspase-3的活化程度（P<0.05）,并不同程度降低COX-2、IL-6和iNOS蛋白表达水平（P<0.05）。地参游离酚通过抑制细胞凋亡、影响细胞周期分布和抑制炎症反应保护CCl₄所致的肝细胞损伤。     

葡萄籽原花青素对顺铂诱导人胚肾细胞凋亡的拮抗作用

目的： 探讨葡萄籽原花青素（ g r a p e s e e d p r o a n t h o c y a n i d i n , G S P E ） 对顺铂（cis-diamminedichloroplatinum,CDDP）诱导人胚肾细胞HEK293凋亡及相关凋亡基因的影响,并探讨可能的机制。方法：体外培养正常HEK293细胞,噻唑蓝法测定GSPE、CDDP分别对HEK293细胞生长的影响以及GSPE对CDDP诱导HEK293细胞毒性的保护作用,流式细胞仪测定GSPE对CDDP所致HEK293细胞凋亡率的变化,Western blotting测定GSPE对CDDP所致HEK293细胞凋亡相关基因Bax、Bcl-2蛋白表达的影响。结果：GSPE对CDDP所致HEK293细胞毒性具有拮抗作用,可减轻CDDP所致HEK293细胞凋亡,减弱Bax表达、增强Bcl-2表达。结论：GSPE对CDDP所致HEK293细胞凋亡具有拮抗作用,其机制可能与GSPE降低促凋亡基因Bax,升高抗凋亡基因Bcl-2的表达有关。