叶黄素干预对早期老年黄斑变性患者生活质量的影响

目的研究叶黄素干预对早期老年黄斑变性(aged-related macular degeneration,AMD)患者生活质量的影响。方法采用随机双盲空白对照法,将108名早期AMD患者随机分为叶黄素低剂量组、叶黄素高剂量组、叶黄素/玉米黄素混合干预组和安慰剂对照组,连续服药48 w。于服药0 w及48 w,进行一般情况、膳食营养摄入状况、最佳矫正视力和视功能相关生存质量测定。结果早期AMD患者整体健康状况、总体视力及近距离活动能力显著下降,且总体视力、近距离活动能力分别与矫正视力呈显著正相关。服用叶黄素后最佳矫正视力和视力得分较用药前呈上升趋势;叶黄素/玉米黄素混合用药组近距离活动能力得分较服药前显著提高(P<0.05)。基线视力、活动受限程度分别与其在用药期间的改变呈负相关。结论叶黄素干预可提高早期AMD患者视力水平,并显著改善其近距离活动能力,提示叶黄素对早期AMD患者生活质量具有一定的保护作用。[营养学报,2012,34(4):327-331]     

叶黄素对大鼠视网膜蓝光光损伤的保护作用

目的观察叶黄素对大鼠视网膜蓝光损伤的保护作用。方法将大鼠随机分为正常对照组、模型对照组、溶剂对照组、叶黄素低、中、高剂量组。叶黄素低、中、高剂量组的浓度分别为0.5、1.0和2.0mg/ml,生理盐水和Tween-80以1∶9的比例配制成溶剂。叶黄素组及溶剂对照组大鼠玻璃体内分别注射不同剂量叶黄素及溶剂,注射量为5μl,暗适应24h,用蓝光损伤装置建立大鼠视网膜光损伤动物模型,光暴露时间为2h,光暴露后暗室饲养,72h后摘取眼球制备眼球壁石蜡切片,显微镜下观察视网膜形态学变化,测量外核层厚度,并计数外核层凋亡细胞。结果各剂量叶黄素组大鼠与模型对照组比,视网膜结构层次分明,细胞排列整齐;视网膜外核层厚度(40×10倍),正常对照组为(21.25±1.04)mm,模型对照组和溶剂对照组分别为(3.25±1.48)mm与(3.25±0.89)mm,叶黄素低、中、高剂量组分别为(15.00±5.58)mm、(11.75±4.20)mm及(14.75±3.96)mm,均显著高于模型对照组(P<0.01)。但该实验采用Tunel试剂盒检测细胞凋亡,各组间未见显著差别。结论在本实验条件下,叶黄素对大鼠视网膜光损伤有明显的保护作用。     

自然光液晶及普通液晶电视对视疲劳影响

目的比较观看自然光液晶电视与普通液晶电视前后视觉疲劳发生程度。方法研究对象为59名20岁左右视力正常的大学生,每名受试者分别观看2.5 h的自然光液晶电视和普通液晶电视,在2次观看电视前后均进行明视持久度、闪烁光临界频率、注意力集中时间、视觉反应时、明度差别阈限等与视疲劳相关指标测试以及主观症状问卷调查。结果自然光液晶电视组与普通液晶电视组观看前后,奇偶数反应时和明度差别阈限差值分别为-0.096,-0.046 s和0.280,2.840 lx,而闪烁光临界频率和明视持久度前后差值大于普通液晶电视组,但差异均无统计学意义(P0.05);观看自然光液晶电视后只有眼胀、眨眼频率增加(P0.05);而观看普通液晶电视后发生眼痛、眼胀、视物模糊、视力下降、眩晕等的频率增加(P0.05)。结论与普通液晶电视比较,观看自然光液晶电视有缓解视觉疲劳的趋势,但有待进一步研究。     

VDT视保护屏对操作者视功能影响的研究

目的　了解电脑显示终端（ＶＤＴ） 视保护屏是否能保护操作者的视功能。方法　对某卫生学校４０ 名１７ ～１８ 岁学生进行,现场研究,观察指标为明视持久度、视觉运动反应时、阅字数、错误率、脑力工作能力指数。结果　操作者明视持久度、反应时、阅字数、脑力工作能力指数四项指标在有屏组与无屏组间比较,无统计学意义（ Ｐ＞ ０．０５） 。错误率在有屏组与无屏组比较中,表现为操作后即刻无屏组高于有屏组（ Ｐ＜ ０．０１）。结论　ＶＤＴ 保护屏（金属丝网型）对操作者视功能未显示明显的保护作用     

越橘提取物复合维生素A对改善视疲劳的实验研究

目的:研究越橘提取物复合维生素A对改善视疲劳的作用。方法:选择视力易疲劳的受试者120名,分为试食组和安慰组,每组60人,试食组口服越橘提取物复合维生素A每日2次,每次1粒,对照组口服颜色、性状与越橘提取物复合维生素A胶囊相同的安慰剂,食用量同试食组,试验期限为30 d。然后进行下列检查:常规观察、安全性检查、眼部症状检查、观察眼部自觉症状、眼科常规检查、明视持久度测定、视力检查。结果:30 d后试食组视疲劳明显减轻,双眼明视持久度平均提高13.23%±10.34%,总有效率51.9%,对照组明视持久度平均提高1.39%±4.74%,总有效率5.8%,经统计学处理差异有显著性。结论:研究表明越橘提取物复合维生素A能有效缓解人体视疲劳。     

子宫内铅暴露对仔鼠牙齿萌出和釉质发育的影响

目的观察母鼠妊娠期间不同剂量铅暴露对仔鼠牙齿萌出情况和釉质发育的影响。方法27只怀孕SD大鼠随机分为铅暴露高剂量组、低剂量组和对照组,每组9只。铅暴露组饮用去离子水中加入醋酸铅进行染毒[以铅(Pb2+)含量计算高剂量组200mg/L、低剂量组50mg/L],对照组饮用去离子水。染毒自大鼠孕第1天持续至自然分娩。仔鼠出生后第26天在下切牙龈乳头水平进行第1次标记,并于出生后第36天在同一牙龈乳头水平行二次标记。第2次标记当日取全血测定血铅并处死仔鼠。测定切牙铅含量,应用立体显微镜观察牙齿形态并测量切牙两次标记间距离,应用电子探针测定切牙釉质钙、磷含量并计算比值。结果高、低剂量铅暴露仔鼠组血铅较对照仔鼠组增高,差异有统计学意义(P<0.01);高、低剂量铅暴露仔鼠组齿铅[(77.3±6.3)、(27.8±4.5)μg/g]与对照仔鼠组[(6.6±0.8)μg/g]相比,差异有统计学意义(P<0.01)。铅暴露仔鼠组切牙较小,牙尖磨耗明显并多见舌侧髓腔暴露,高铅剂量组更为明显。高、低剂量铅暴露仔鼠组切牙萌出速率[(0.25±0.08)、(0.30±0.09)mm/d]与对照仔鼠组[(0.39±0.09)mm/d]比较,铅暴露组萌出较为缓慢,三组间差异有统计学意义(P<0.01)。仔鼠釉质钙/磷比分析显示,随铅染毒剂量的增加,钙/磷比(1.68±0.54、1.37±0.47)降低,     

大豆异黄酮对绝经早期妇女围绝经期症状的改善效应观察

目的确定大豆异黄酮(soybean isoflavone,SI)改善由于雌激素缺失导致的围绝经期症状的生理效应有效剂量,并探讨其可能机制。方法90例45～60岁的绝经早期妇女,随机单盲分为SI84、126mg/(kgbw·d)两个剂量组和安慰剂对照组,每组30人接受追踪观察24w,每4w要求对象记录1w的潮热、出汗次数,做1次围绝经期症状评分(Kuppermanuscore),并在试验前、12w和24w时测定血清雌二醇(E2)、促卵泡生成素(FSH)和黄体生成素(LH)的浓度。结果在试验期间低、高剂量两组的潮热次数(%)分别为57.8±37.4和56.7±26.7和症状评分的下降率(%)分别为44.3±19.1和48.5±27.2,两组间无显著差异,而安慰剂组的潮热次数和症状评分下降率仅为(34.6±46.2)%和(27.8±15.5)%,显著低于前两组。血清E2、FSH和LH在试验各期各组间没有显著差异。结论大豆异黄酮84mg/d可以改善各种围绝经期症状,尤其是潮热、出汗症状,此效应与激素的调节关系不明显。     

槟榔加工业作业人员视觉疲劳影响的研究

目的了解槟榔加工业作业人员视觉疲劳情况。方法选择从事槟榔加工的56名作业人员,测定他们在工作前、工作中、工作结束时的明视持久度,运动反应时,并分析测试结果的变化率。结果观察组临床症状和体征阳性率显著高于对照组(P<0.05)。选籽、切籽与点卤作业工人明视持久度、视觉运动反应时显著高于对照组(P<0.05)。结论槟榔加工业对作业人员的视觉疲劳有一定的影响。     

叶黄素对大鼠视网膜蓝光损伤防护作用机制研究

目的探讨叶黄素防护视网膜蓝光损伤的相关机制。方法将大鼠按体重随机分为6组:正常对照组、模型对照组、溶剂对照组以及叶黄素低、中、高剂量组。叶黄素低、中、高剂量组分别注射0.5、1.0和2.0mg/ml的叶黄素,溶剂对照组注射由生理盐水和Tween80以9:1混合的溶剂,注射剂量均为5μl。暗适应24h,利用蓝光光损伤仪建立大鼠视网膜光损伤模型,光暴露时间为2h。光暴露结束后暗适应72h,处死取视网膜测定氧化应激指标、神经元型一氧化氮合酶(nNOS)和c-fos蛋白的表达情况。结果与模型对照组及溶剂对照组相比,叶黄素剂量组大鼠视网膜中丙二醛(MDA)含量显著减少(P<0.05),而SOD和GSH-Px的活性在各组间差异无显著性。叶黄素剂量组大鼠视网膜中c-fos蛋白的表达量低于溶剂对照组和模型对照组(P<0.05),而nNOS的表达量与其他组相比差异无显著性(P>0.05)。结论叶黄素可能通过淬灭氧自由基,抑制脂质过氧化和c-fos基因的表达发挥其保护作用。     

核酸对铅中毒大鼠DNA掼伤的影响

目的 研究核酸对铅中毒大毒淋巴细胞、肝细胞和脑细胞DNA损伤的保护作用.方法 纯种雄性健康Wistar大鼠,随机分为4组空白组、模型组、核酸低剂量(200 mg/kg体重)组、核酸高剂量(700mg/kg体重)组.空白组正常饮水,其余3组饮0.8%醋酸铅水溶液;核酸组灌胃核酸,空白组、模型组灌蒸馏水5 w后,采用单细胞凝胶电泳技术对淋巴细胞、肝细胞和脑细胞DNA损伤进行分析.结果 模型组大鼠淋巴细胞、肝、脑细胞DNA的迁移率(50.25±6.21、56.25±6.71、38.13±5.28)和尾长(23.25±4.23、27.63±4.98、37.63±5.37)显著高于卒白组(6.88±1.13、8.25±1.28、8.63±1.19;6.75±1.17、7.88±O.99、5.13±0.84),核酸组大鼠淋巴细胞、肝、脑细胞DNA的迁移率(低剂量组41.25±6.96、42.25±6.09、28.13±3.76,高剂量组35.38±5.93、39.25±7.17、23.88±3.23)和尾长(低剂量16.50±4.24、19.25±3.54、26.00±5.24,高剂量13.63±2.62、18.50±5.48、22.38±5.61)显著低于模型组,差异均具有统计学意义(均P＜0.05).结论 慢性铅染毒可导致大鼠淋巴细胞、肝、脑细胞DNA损伤,饮食核酸对淋巴细胞、肝、脑细胞DNA损伤具有一定的保护作用,可减轻铅中毒引起的氧化损伤.     

Potential Antioxidant Effects of Zinc and Chromium Supplementation in People with Type 2 Diabetes Mellitus

Objective: To determine the effects of combined zinc (Zn) and chromium (Cr) supplementation on oxidative stress and glucose homeostasis of people with type 2 diabetes.

Design: Tunisian adult subjects with HbA1C >7.5% were supplemented for 6 months with 30 mg/d of Zn as Zn gluconate or 400 μg/d of Cr as Cr pidolate or combined Zn/Cr supplementation or placebo. The effects of supplementation on plasma zinc (Zn), copper (Cu), selenium (Se), urinary Zn, Cr, plasma thiobarbituric acid reactive substances (TBARS), Cu-Zn superoxide dismutase (SOD) and Se glutathione peroxidase (GPx) in red blood cells, blood lipids and lipoproteins, HbA1C and fasting glucose were measured at the beginning of the study and after six months.

Results: At the beginning of the study, more than 30% of the subjects may have been Zn deficient with plasma Zn values less than 10.7 μmol/L, whereas levels of plasma Cu, Se and antioxidant RBC enzyme activities were in the normal ranges. Following supplementation, there were significant decreases of plasma TBARS in the Cr (13.6%), Zn (13.6%) and Zn/Cr (18.2%) groups with no significant changes in the placebo group. The value for the TBARS of the control healthy Tunisian subjects was 2.08 ± 0.04 μmol/L and that of the Tunisian subjects with diabetes was 3.32 ± 0.05 μmol/L. This difference of 1.24 μmol/L between the control group and the subjects with diabetes was reduced from 36% to 50% in the three supplemented groups. Supplementation did not modify significantly HbA1C nor glucose homeostasis. No adverse effects of Zn supplementation were observed on Cu status, HDL cholesterol nor interactions in Zn or Cr.

Conclusions: These data suggest the potential beneficial antioxidant effects of the individual and combined supplementation of Zn and Cr in people with type 2 DM. These results are particularly important in light of the deleterious consequences of oxidative stress in people with diabetes.     

Differences in Erythrocyte Folate Concentrations in Older Adults Reached Steady-State within One Year in a Two-Year, Controlled, 1 mg/d Folate Supplementation Trial

Daily supplementation with folate increases erythrocyte folate concentrations; however, the time to reach steady-state concentrations has not been empirically demonstrated. Previous predictions of time to steady state or time to 90% steady-state concentration, based on modeling changes in erythrocyte folate during short-term trials, range widely from 40 to 86 wk. We sought to determine the time to steady-state erythrocyte folate concentrations following the initiation of daily folate supplementation using data collected from a 2-y, double-blind, placebo-controlled, randomized trial involving 276 participants aged 65 y or older. The daily supplement contained 1 mg of folate. Erythrocyte folate concentrations were measured, using a microbiological assay, at baseline and at 6, 12, 18, and 24 mo. The mean plasma and erythrocyte folate concentrations in the folate-supplemented group were higher than in the placebo group at 6, 12, 18, and 24 mo (P < 0.001). Adjusted for baseline differences, the difference in erythrocyte folate concentrations between the folate and placebo group at 6 mo was 1.78 μmol/L (95% CI: 1.62-1.95 μmol/L). The difference increased significantly to 2.02 μmol/L (95% CI: 1.85-2.18 μmol/L) at 12 mo. This difference (between the folate and placebo groups) did not significantly change after a further year of folate supplementation; at 18 mo, it was 2.09 μmol/L (95% CI: 1.92-2.27 μmol/L) and at 24 mo it was 1.98 μmol/L (95% CI: 1.18-2.15 μmol/L). Twelve months of daily folate supplementation with 1 mg is sufficient time to cause erythrocyte folate concentrations to reach a new steady state.     

电视屏幕闪烁对人体视觉调节功能影响的研究

目的 了解电视屏幕闪烁对人体视觉功能的不同影响。方法 选择视力正常的60名大学生为研究对象,采用眼调节近点、集合近点、视觉反应时、明视持久度、闪光融合临界频率的测定,了解观看无闪烁电视与普通电视3h前后人体视觉功能的变化。结果 观看3h无闪烁电视,受试视觉调节功能下降、视觉疲劳程度加大、注视的持久力减弱比观看普通电视要小。结论 视屏闪烁会影响视觉调节功能,可导致视觉系统紧张而出现视疲劳。     

组蛋白去乙酰化酶2基因在苯并（a）芘致神经细胞凋亡中的量效和时效表达

[目的]通过体外培养细胞途径研究组蛋白去乙酰化酶2（HDAC2）基因在苯并（a）芘[B（a）P]所致神经细胞凋亡中的量效和时效表达。[方法]大鼠原代培养的神经元细胞分为两批：第一批分4个组,以B（a）P同时加入s9对细胞染毒,分别为二甲基亚砜（DMSO）组、低剂量组、中剂量组、高剂量组,使其终浓度为0、10、20、40gmol／L,继续培养48h;第二批分5个组,以20gmol／LB（a）P染毒,分别于染毒0、6、12、24、48h处理细胞。用流式细胞术检测神经细胞的凋亡率,实时荧光定量PCR法检测caspase-3,HDAC2基因的量效和时效表达情况。[结果]①流式细胞术结果显示,与DMSO组相比,中、高剂量组神经细胞的凋亡率明显增加（P〈O．05）;与低剂量组相比,高剂量组凋亡率增加（P〈0．05）。与0h组相比,染毒24、48h组神经细胞的凋亡率明显增加（P〈0．05）。②与DMSO组相比,高剂量组caspase-3、HDAC2mRNA的表达量明显增加（P〈0．01）;与低剂量组相比,高剂量组caspase-3mRNA表达量明显增加（P〈0．05）。与0h组相比,染毒48h组caspase-3、HDAC2mRNA表达量明显升高（P〈0．01,P〈0．05）。[结论]B（a）P可引起神经细胞凋亡,HDAC2基因表达上升,该基因可能在B（a）P所导致的神经细胞凋亡中起重要作用。     

砷对Keap1抑制HaCaT细胞凋亡及抗氧化水平的影响

目的 基于抑制Kelch样环氧氯丙烷相关蛋白1（Kelch-like ECH-assoicated protein 1,Keap1）基因,研究砷对人永生化角质形成细胞凋亡及抗氧化水平的影响。方法 培养细胞72 h,分为5组:空白对照组、阴性对照（Keap1基因抑制未染砷）、Keap1基因抑制+低砷（2.9 μmol/L）、Keap1基因抑制+中砷（5.8 μmol/L）和Keap1基因抑制+高砷（29.0 μmol/L）组;用流式细胞仪检测细胞凋亡率;用实时荧光定量聚合酶链式反应检测核因子E2相关因子2（nuclear factor erythroid 2-related factor 2,Nrf2）、Keap1 mRNA水平;采用酶联免疫吸附试验检测谷胱甘肽、血红素氧化酶、环氧化酶、S-腺苷甲硫氨酸与同型半胱氨酸蛋白水平。结果 Nrf2和Keap1 mRNA表达不全相等（均有P<0.05）;与阴性对照组相比,低砷组S-腺苷甲硫氨酸和同型半胱氨酸蛋白表达上调（均有P<0.05）,血红素氧化酶蛋白在低、中、高砷组均上调（均有P<0.05）,环氧化酶蛋白在中、高砷组上调（均有P<0.05）,谷胱甘肽蛋白在高砷组上调（F=7.24,P=0.001）。结论 基于Keap1基因抑制,砷暴露上调抗氧化酶活性,提高抗氧化水平,细胞凋亡下降;随着砷剂量增加,Nrf2表达下调,抗氧化水平失衡,细胞凋亡增加。     

High-dose selenium for critically ill patients with systemic inflammation: Pharmacokinetics and pharmacodynamics of selenious acid: A pilot study

ObjectiveSystemic inflammatory response syndrome is characterized by increased urinary excretion of selenium and low serum concentration. Repletion by parenteral selenite is the most efficacious form of supplementation. However, the optimum safe dose and mode of administration remain controversial. We aimed to determine pharmacokinetic and pharmacodynamic profiles of selenite and estimate a safe dose to optimize selenium status.MethodsA prospective, randomized, pilot study in 20 patients with systemic inflammatory response syndrome compared a high-dose (HD) group that received a loading dose of selenium as selenite 15.18 μmol over 2 h and thereafter 10.12 μmol/d as a continuous intravenous infusion (CIV) for 10 d with a very–high-dose (VHD) group that received a loading dose of 25.30 μmol over 2 h and thereafter 20.24 μmol as a CIV for 10 d. Clinical outcome was evaluated by length of stay in the intensive care unit, incidence of ventilator-associated pneumonia, and Sequential Organ Failure Assessment score.ResultsPatients in group HD (n = 10, age 54 ± 23 y) had an Acute Physiology and Chronic Health Evaluation II score of 23 ± 5 and a Sequential Organ Function Assessment score of 10 ± 2. Those in group VHD (n = 10, age 41 ± 19 y) had scores of 21 ± 7 and 8 ± 3, respectively. Pharmacokinetic concentration/time curves for serum selenium overlapped but were independent of dose, whereas the pharmacodynamics were different, showing maximum glutathione peroxidase activity only with VHD. Glutathione peroxidase decreased after day 7 independently of the selenium dose. Clinical outcomes were similar in both groups.ConclusionA bolus loading dose of selenite providing 2000 μg of selenium (25.30 μmol) followed by a CIV of 1600 μg/d (20.24 μmol/d) for 10 d is most effective at returning serum selenium to physiologic levels and safely maximizing glutathione peroxidase activity.     

Effects of curcumin on retinal oxidative stress and inflammation in diabetes

Background

Age-related macular degeneration (AMD) is a disease with multiple risk factors, many of which appear to involve oxidative stress. Macular pigment, with its antioxidant and light-screening properties, is thought to be protective against AMD. A result has been the appearance of dietary supplements containing the macular carotenoids, lutein and zeaxanthin. More recently, a supplement has been marketed containing, in addition, the third major carotenoid of the macular pigment, meso-zeaxanthin. The purpose of the study was to determine the effectiveness of such a supplement in raising macular pigment density in human subjects.

Methods

A 120 day supplementation study was conducted in which 10 subjects were given gel-caps that provided 20 mg/day of predominantly meso-zeaxanthin, with smaller amounts of lutein and zeaxanthin. A second group of 9 subjects were given gel caps containing a placebo for the same 120 day period. Prior to and during the supplementation period, blood serum samples were analyzed by high performance liquid chromatography for carotenoid content. Similarly, macular pigment optical density was measured by heterochromatic flicker photometry. Differences in response between the supplementation and placebo groups were tested for significance using a student's t-test.

Results

During supplementation with the carotenoids, blood samples revealed the presence of all three carotenoids. Macular pigment optical density, measured at 460 nm, rose at an average rate of 0.59 ± 0.79 milli-absorbance unit/day in the 10 supplemented subjects. This was significantly different from the placebo group (9 subjects) for whom the average rate was -0.17 ± 0.42 milli-absorbance units/day.

Conclusion

We have shown for the first time that meso-zeaxanthin is absorbed into the serum following ingestion. The data indicate that a supplement containing predominantly meso-zeaxanthin is generally effective at raising macular pigment density, and may turn out to be a useful addition to the defenses against AMD.     

服用抗氧化剂降低老年人血清脂质过氧化物——随机双盲临床试验

给某老年人护理院的45位老人服用β-胡萝卜素,维生素B_6,维生素C,维生素E,锌和硒,或者相应的安慰剂作为日常食物的补充,为期一年。开始时,这些老年人的血清脂质过氧化物水平(2.7±0.7μmol/L)高于作为对照组的年轻健康成年人(2.3±0.6μmol/L),P<0.01。服药三个月后,老年人的血清脂质过氧化物已降至2.2±0.6μmol/L,并且保持这一低水平直到研究结束,而服安慰剂者血清脂质过氧化物无变化。 血清脂质过氧化物与全血硒浓度呈显著负相关(r=-0.428,P<0.01),但只有在血硒高于200μg/L时才可见血清脂质过氧化物的降低。血清α-维生素E浓度也与血清脂质过氧化物呈负相关,但相关程度(r=-0.273,P<0.76)低于与血硒间的相关。 从生物化学角度看,25％的老年人可观察到维生素B_6缺乏;每天补充2mg维生素B_6彻底治愈了全部的病例。服药组经几项心理学检验有轻微改善,而服用安慰剂的对照组无变化或者恶化。护士报告在服药组中见有临床改善,未见有毒性副作用。老年人服用抗氧化剂从生物化学和临床上都是有益的。