检索结果-内蒙古大学图书馆

Molecular basis of vitamin e action -: Tocotrienol potently inhibits glutamate-induced pp60^c-Src kinase activation and death of HT4 neuronal cells

引用

JOURNAL OF BIOLOGICAL CHeMISTRY 2000年第17期275卷 13049-13055页

作者： Sen, CK Khanna, S Roy, S Packer, L Univ Calif Berkeley Lawrence Berkeley Lab Berkeley CA 94720 USA Univ Calif Berkeley Dept Mol & Cell Biol Berkeley CA 94720 USA

HT4 hippocampal neuronal cells were studied to compare the efficacy of tocopherols and tocotrienol to protect against glutamate-induced death. Tocotrienols were more effective than alpha-tocopherol in preventing glutamate-induced death. Uptake of tocotrienols from the culture medium was more efficient compared with that of alpha-tocopherol. Vitamin e molecules have potent antioxidant properties. Results show that at low concentrations, tocotrienols may have protected cells by an antioxidant-independent mechanism. examination of signal transduction pathways revealed that protein tyrosine phosphorylation processes played a central role in the execution of death. Activation of pp60(c-Src) kinase and phosphorylation of eRK were observed in response to glutamate treatment. Nanomolar amounts of cy-tocotrienol, but not alpha-tocopherol, blocked glutamate-induced death by suppressing glutamate-induced early activation of c-Src kinase. Overexpression of kinase-active c-Src sensitized cells to glutamate-induced death. Tocotrienol treatment prevented death of Src-overexpressing cells treated with glutamate. alpha-Tocotrienol did not influence activity of recombinant c-Src kinase suggesting that its mechanism of action may include regulation of SH domains. This study provides first evidence describing the molecular basis of tocotrienol action. At a concentration 4-10-fold lower than levels detected in plasma of supplemented humans, tocotrienol regulated unique signal transduction processes that were not sensitive to comparable concentrations of tocopherol.

关键词：苯醌类细胞死亡细胞培养的螯合剂/药理学色满类/代谢色谱法高压液相去铁胺/药理学酶激活酶抑制剂/药理学流式细胞术谷氨酸/代谢海马/药物作用免疫印迹法内酰胺类大环神经元/药物作用磷酸酪氨酸/代谢原癌基因蛋白质pp60(c-src)/代谢醌类/药理学信号传导时间因素生育三烯酚类转染维生素e/类似物和衍生物维生素e/代谢维生素e/药理学动物小鼠大鼠

来源：评论

学校读者我要写书评

暂无评论

Analysis of all-rac-α-tocopheryl acetate and retinyl palmitate in medical foods using a zero control reference material (ZRM) as a method development tool

引用

JOURNAL OF AOAC INTeRNATIONAL 1999年第2期82卷 271-275页

作者： Chase, GW eitenmiller, RR Long, AR US FDA Atlanta Ctr Nutr Anal Atlanta GA 30309 USA Univ Georgia Dept Food Sci & Technol Athens GA 30602 USA

A liquid chromatographic method is described for analysis of all-rac-alpha-tocopheryl acetate and retinyl palmitate in medical food. The vitamins are extracted in isopropyl alcohol and hexane-ethyl acetate without saponification and quantitated by normal-phase chromatography with fluorescence detection. All-rac-alpha-tocopheryl acetate and retinyl palmitate are chromatographed isocratically with a mobile phase of 0.5% (v/v) and 0.125% (v/v) isopropyl alcohol in hexane, respectively. Recovery studies performed on a medical food zero control reference material (ZRM) fortified with the analytes averaged 99.7% (n = 25) for retinyl palmitate and 101% (n = 25) for all-rac-a-tocopheryl acetate. Coefficients of variation were 0.87-2.63% for retinyl palmitate and 1.42-3.20% for all-rac-alpha-tocopheryl acetate. The method provides a rapid, specific, and easily controlled assay for analysis of vitamin A and vitamin e in medical foods. Use of chlorinated solvents is avoided.

关键词：色谱法/方法食品配方/分析婴儿食品/分析质量控制参考标准光谱法荧光立体异构现象生育酚类维生素A/类似物和衍生物维生素A/分析维生素e/类似物和衍生物维生素e/分析 α生育酚/类似物和衍生物

来源：评论

学校读者我要写书评

暂无评论

A liquid chromatographic method for analysis of all-rac-α-tocopheryl acetate and retinyl palmitate in medical food using matrix solid-phase dispersion in conjunction with a zero reference material as a method development tool

引用

JOURNAL OF AOAC INTeRNATIONAL 1999年第1期82卷 107-111页

作者： Chase, GW eitenmiller, RR Long, AR US FDA Atlanta Ctr Nutrient Anal Atlanta GA 30309 USA Univ Georgia Dept Food Sci & Technol Athens GA 30602 USA

A liquid chromatographic method is described for analysis of all-rac-alpha-tocopheryl acetate and retinyl palmitate in medical food. The vitamins are extracted from medical food without saponification by matrix solid-phase dispersion and chromatographed by normal-phase chromatography with fluorescence detection. Retinyl palmitate and all-rac-alpha-tocopheryl acetate are quantitated isocratically with a mobile phase of 0.125% (v/v) and 0.5% (v/v) isopropyl alcohol in hexane, respectively. Results compared favorably with label declarations on retail medical foods. Recoveries determined on an analyte-fortified zero reference material for a milk-based medical food averaged 98.3% (n = 25) for retinyl palmitate spikes and 95.7% (n = 25) for all-rac-alpha-tocopheryl acetate spikes. Five concentrations were examined for each analyte, and results were linear (r(2) = 0.995 for retinyl palmitate and 0.9998 for all-rac-alpha-tocopheryl acetate) over the concentration range examined, with coefficients of variation in the range 0.81-4.22%. The method provides a rapid, specific, and easily controlled assay for analysis of retinyl palmitate and all-rac-alpha-tocopheryl acetate in fortified medical foods.

关键词：色谱法液相食品配方/分析参考标准结果可重复性立体异构现象生育酚类维生素A/类似物和衍生物维生素A/分析维生素e/类似物和衍生物维生素e/分析 α生育酚/类似物和衍生物

来源：评论

学校读者我要写书评

暂无评论

Vitamin e (d-α-tocopheryl succinate) decreases mitotic accumulation in γ-irradiated human tumor, but not in normal, cells

引用

NUTRITION AND CANCeR-AN INTeRNATIONAL JOURNAL 1999年第2期35卷 189-194页

作者： Jha, MN Bedford, JS Cole, WC edward-Prasad, J Prasad, KN Univ Colorado Hlth Sci Ctr Sch Med Dept RadiolCtr Vitamins & Canc Res Denver CO 80262 USA Colorado State Univ Dept Radiol Hlth Sci Ft Collins CO 80523 USA

Previous studies have shown that treatment of tumor cells in vitro with d-alpha-tocopheryl succinate (alpha-TS), a most effective form of vitamin e, alone or in combination with X-irradiation, reduced the growth of these cells more than that produced by individual agents. However, it is unknown whether alpha-TS, alone or in combination with gamma-irradiation, would produce similar effects on normal cells. To study this, we have compared the effects of alpha-TS on three human tumor cell lines, HeLa (cervical carcinoma), OVGI (ovarian carcinoma), and A549 (lung carcinoma), with the effects on three human normal fibroblast lines, GM2149, AG1522, and HF19. Results showed that alpha-TS treatment of HeLa cells for 20 hours caused inhibition of growth in a dose-dependent manner, but normal human fibroblasts treated similarly with alpha-TS did not show such an effect. alpha-TS treatment for 20 hours also decreased mitotic accumulation in all three tumor cell lines but did not produce such an effect in any of the normal fibroblasts. As expected, gamma-irradiation with I Gy decreased mitotic accumulation in human tumor cells and normal fibroblasts, however, alpha-TS treatment for 24 hours before, during, and after irradiation for the entire experimental period further decreased mitotic accumulation in human tumor cells but not in normal cells. These data suggest that effects of alpha-TS, alone or in combination with gamma-irradiation, are selective for tumor cells. Therefore, existing fear that antioxidants such as vitamin e may protect cancer cells from free radical damage during radiation therapy is not justified.

关键词：细胞分裂/药物作用成纤维细胞/药物作用 γ射线 HeLa细胞/病理学肺肿瘤/病理学有丝分裂/药物作用肿瘤/病理学卵巢肿瘤/病理学肿瘤细胞培养的维生素e/类似物和衍生物维生素e/药理学女(雌)性人类

来源：评论

学校读者我要写书评

暂无评论

effects of vitamin e and selenium supplementation on esophageal adenocarcinogenesis in a surgical model with rats

引用

CARCINOGeNeSIS 2000年第8期21卷 1531-1536页

作者： Chen, XX Mikhail, SS Ding, YW Yang, GY Bondoc, F Yang, CS Rutgers State Univ Coll Pharm Canc Res Lab Piscataway NJ 08854 USA

Two well-known antioxidative nutrients, vitamin e and selenium, were used in this study to investigate possible inhibitory action against the formation of esophageal adenocarcinoma (eAC) in rats. In this model, carcinogenesis is believed to be driven by oxidative stress. Male Sprague-Dawley rats (8 weeks old) were divided into four groups and received esophagoduodenal anastomosis (eDA) surgery plus iron supplementation (12 mg/kg/week), Vitamin e and selenium were supplemented in the diet in the forms of alpha-tocopheryl acetate (750 IU/kg) and sodium selenate (1.7 mg Se/kg), which were 10 times the regular amounts in the basic AIN93M diet. At 40 weeks after surgery, all the eDA groups had lower body weights than the non-operated control group. Iron nutrition (hemoglobin, total serum iron and transferrin saturation) was normal as a result of iron supplementation after eDA, Vitamin e supplementation maintained the normal plasma level of alpha-tocopherol in eDA rats, but not those of gamma-tocopherol and retinol, Selenium supplementation increased the serum and liver selenium contents of the eDA rats. Histopathological analysis showed that selenium supplementation increased the incidence of eAC and the tumor volume. The selenium level in the tumor is higher than that in the duodenum of the same animal,Vitamin e supplementation, however, inhibited carcinogenesis, especially in the selenium-supplemented group. We believe that vitamin e exerts its effect through its antioxidative properties, and a high dose of inorganic selenium may promote carcinogenesis by enhancing oxidative stress.

关键词：吸收腺癌/病因学腺癌/预防和控制吻合术外科抗致癌药/治疗应用抗氧化剂/治疗应用营养保健品疾病模型动物十二指肠造口术食管肿瘤/病因学食管肿瘤/预防和控制食管造口术铁右旋糖酐复合物/投药和剂量肝/代谢氧化性应激大鼠 Sprague-Dawley 硒化合物/药代动力学硒化合物/治疗应用维生素e/类似物和衍生物维生素e/治疗应用 α生育酚/类似物和衍生物动物男(雄)性大鼠

来源：评论

学校读者我要写书评

暂无评论

Vitamin e reduces chromosomal damage and inhibits hepatic tumor formation in a transgenic mouse model

引用

PROCeeDINGS OF THe NATIONAL ACADeMY OF SCIeNCeS OF THe UNITeD STATeS OF AMeRICA 2000年第5期97卷 2196-2201页

作者： Factor, VM Laskowska, D Jensen, MR Woitach, JT Popescu, NC Thorgeirsson, SS NCI Expt Carcinogenesis Lab NIH Bethesda MD 20892 USA

We have previously shown that chronic activation of mitogenic signaling induced by over-expression of c-myc and transforming growth factor-alpha (TGF alpha) transgenes in mouse liver induces a state of oxidative stress. We therefore proposed that increased reactive oxygen species (ROS) generation might be responsible for the extensive chromosomal damage and acceleration of hepatocarcinogenesis characteristic: for TGF alpha/c-myc mice. In this study, we show that vitamin e (Ve), a potent free radical scavenging antioxidant, is able to protect liver tissue against oxidative stress and suppress tumorigenic potential of c-myc oncogene, Dietary supplementation with Ve, starting from weaning, decreased ROS generation coincident with a marked inhibition of hepatocyte proliferation while increasing the chromosomal as well as mtDNA stability in the liver. Similarly, dietary Ve reduced liver dysplasia and increased viability of hepatocytes, At 6 mo of age, Ve treatment decreased the incidence of adenomas by 65% and prevented malignant conversion. These results indicate that ROS generated by over-expression of c-myc and TGF alpha in the liver are the primary carcinogenic agents in this animal model. Furthermore, the data demonstrate that dietary supplementation of Ve can effectively inhibit liver cancer development.

关键词：抗氧化剂/代谢抗氧化剂/药理学 DNA损伤 DNA 线粒体营养保健品疾病模型动物肝/病理学肝肿瘤/遗传学肝肿瘤/代谢肝肿瘤/预防和控制小鼠近交C57BL 小鼠转基因活性氧/代谢维生素e/类似物和衍生物维生素e/代谢维生素e/药理学 α生育酚/类似物和衍生物动物小鼠

来源：评论

学校读者我要写书评

暂无评论

effects of UV light and tumor promoters on endogenous vitamin e status in mouse skin

引用

CARCINOGeNeSIS 2000年第2期21卷 221-225页

作者： Liebler, DC Burr, JA Univ Arizona Coll Pharm Dept Pharmacol & Toxicol Tucson AZ 85721 USA Univ Arizona Coll Pharm SW Environm Hlth Sci Ctr Tucson AZ 85721 USA

Recent reports indicate that both orally administered and topically applied alpha-tocopherol (vitamin e, Tn) prevent UVB-induced skin carcinogenesis in mice. Because UVB exposure causes the formation of oxidants associated with tumor promotion, epidermal Tn status may be an important determinant of susceptibility to photocarcinogenesis. To test this hypothesis, we studied the status of epidermal Tn in C3H mice following exposure to single and repeated UVB exposures at doses typical of chronic photocarcinogenesis protocols. exposure of mice to a single 13 kJ/m(2) dose over 60 min resulted in no acute depletion of epidermal Tn and a modest increase in TH within 6-12 h. Daily exposure to 6.5 kJ/m(2) over 30 min resulted in a gradual increase in epidermal Tn, which reached 5-fold after five daily exposures. The increase in epidermal TH was accompanied by an increase in the Tn oxidation products alpha-tocopherolquinone (TQ) and alpha-tocopherolhydroquinone (THQ), We also studied the effect of the prooxidant chemical tumor promoter benzoyl peroxide and the prooxidant azo initiators azobis(amidinopropane HCl) and azobis(2,4-dimethylvaleronitrile). Topical application of these prooxidant chemicals acutely oxidized epidermal Tn to TQ and THQ. Topical treatments with the phorbol ester tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) increased epidermal Tn levels without producing a significant accumulation of Tn oxidation products, The results indicate that UVB and tumor promoting chemicals all exert qualitatively different effects on epidermal Tn status and that UVB and TPA trigger an adaptive response involving epidermal Tn accumulation.

关键词：脒类/药理学抗氧化剂/代谢偶氮化合物/药理学过氧苯甲酰/药理学致癌物/药理学辅致癌作用表皮/药物作用表皮/代谢表皮/辐射效应氢醌类/代谢小鼠近交C3H 腈类/药理学氧化性应激光化学十四酰佛波乙酯/药理学紫外线维生素e/类似物和衍生物维生素e/代谢 α生育酚/类似物和衍生物动物女(雌)性小鼠

来源：评论

学校读者我要写书评

暂无评论

Reduced reperfusion injury in muscle - A comparison of the timing of ePC-K1 administration in rats

引用

ACTA ORTHOPAeDICA SCANDINAVICA 1999年第2期70卷 207-211页

作者： Hirose, J Yamaga, M Takagi, K Kumamoto Univ Sch Med Dept Orthoped Surg Kumamoto 8608556 Japan

ePC-K1, a phosphate diester of alpha-tocopherol and ascorbic acid, is a new hydroxyl radical scavenger. We examined the effects of ePC-K1 according to differences in the timing of its administration. Warm ischemia, produced by vascular pedicle clamping, was sustained for 4 hours. After 24 hours of reperfusion, muscle injury was evaluated in 4 groups: the first group received a sham operation, the second group was treated with an intravenous injection of ePC-K1 prior to ischemia, the third group was treated with ePC-K1 prior to reperfusion, and the fourth group was controls. Compared with the control group, both the preischemic and pre-reperfusion ePC-K1-treated groups showed a statistically significant amelioration in the reduction of isometric muscle contraction. There were also significant reductions in the muscle and serum levels of thiobarbituric acid reactive substances (TBA-RS) and muscle damage, indicated by the biochemical and histological study. A comparison of the timing of ePC-K1 administration revealed that only the muscle TeARS level in the pre-reperfusion ePC-K1-treated group was significantly higher than that in the preischemic ePC-K1-treated group. These observations indicate that ePC-K1 not only by preischemic but also by pre-reperfusion administration acted effectively on reperfusion injury in muscle, thereby improving muscle function.

关键词：硫巴比妥酸反应物/代谢时间因素维生素e/投药和剂量维生素e/类似物和衍生物

来源：评论

学校读者我要写书评

暂无评论

Antioxidant reactions of α-tocopherolhydroquinone

引用

LIPIDS 2000年第9期35卷 1045-1047页

作者： Liebler, DC Burr, JA Univ Arizona Coll Pharm Dept Pharmacol & Toxicol Tucson AZ 85721 USA Univ Arizona Coll Pharm SW Environm Hlth Sci Ctr Tucson AZ 85721 USA

alpha-Tocopherolhydroquinone (TQH(2)) is a product of alpha-tocopherol oxidation/reduction that exerts antioxidant effects in biological systems. TQH(2) inhibited autoxidation of methyl linoleate initiated by peroxyl radicals derived from thermolysis of 2,2'-azobis(2,4-dimethylvaleronitrile) in acetonitrile. TQH(2) oxidation yielded alpha-tocopherolquinone (TQ) as a major product and 2,3-epoxy-alpha-tocopherolquinone and 5,6-epoxy-alpha-tocopherolquinone as minor products. each TQH(2) consumed approximately two peroxyl radicals in the course of the oxidation. The data suggest that TQH(2) scavenges peroxyl radicals primarily by electron transfer to form TQ and secondarily by addition-elimination to form the epoxyquinones.

关键词：抗氧化剂/化学抗氧化剂/代谢环氧化合物/代谢自由基清除剂/代谢氢醌类/化学氢醌类/代谢动力学亚油酸类/代谢分子结构氧化还原过氧化物/代谢维生素e/类似物和衍生物维生素e/化学维生素e/代谢 α生育酚/类似物和衍生物

来源：评论

学校读者我要写书评

暂无评论

引用

JOURNALS OF GeRONTOLOGY SeRIeS A-BIOLOGICAL SCIeNCeS AND MeDICAL SCIeNCeS 1999年第9期54卷 B379-B383页

作者： Yanagawa, K Takeda, H egashira, T Sakai, K Takasaki, M Matsumiya, T Tokyo Med Univ Dept Pharmacol Shinjuku Ku Tokyo 1608402 Japan Tokyo Med Univ Dept Geriatr Shinjuku Ku Tokyo 1608402 Japan Oita Med Univ Dept Pharmacol Oita Japan Oita Med Univ Res Lab Ctr Dept Med Oita Japan

Age-related changes in alpha-tocopherol dynamics in plasma and erythrocyte membranes of 10- to 120-week-old rats were investigated by high-performance liquid chromatography (HPLC) whit redon detection mode. Furthermore, changes in lipid hydroperoxide content and fluidity of erythrocyte membrane with age Here assessed using chemiluminescence-HPLC and Fourier transforms infrared spectrophotometer, respectively. A slight increase in the alpha-tocopherolquinone/alpha-tocopherol ratio ill erythrocyte membrane and a decrease in the alpha-tocopherol in erythrocyte membrane/alpha-tocopherol in plasma ratio were observed. A significant increase in lipid hydroperoxide content and a marked decrease in the fluidity of erythrocyte membrane were seen with age. These findings suggest that alpha-tocopherol uptake in erythrocyte membrane declines, and utilization rate of alpha-tocopherol in erythrocyte membrane increases age-dependently. These changes, which enhanced lipid-peroxidation and consequently reduced membrane fluidity, may be caused by the impairment of this transfer mechanism.

关键词：衰老/血液红细胞膜/代谢过氧化脂质类/血液膜流动性磷脂酰胆碱类/血液大鼠 Sprague-Dawley 维生素e/类似物和衍生物维生素e/血液动物男(雄)性大鼠

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：