Dietary sitostanol reciprocally influences cholesterol absorption and biosynthesis in hamsters and rabbits

The aim of this study was to examine the efficacy of variable dietary sitostanol (SI) concentrations on cholesterol absorption, synthesis and excretion rates in two animal models. Hamsters and rabbits were fed semi-purified diets supplemented with cholesterol and 1% (w/w) phytosterols containing either 0.007, 0.17, 0.8 or 1% (w/w) SI. The control (0% (w/w) SI) groups consumed the same diets but no phytosterols were added. The dual-isotope plasma ratio of [13C]- and [18O]cholesterol and deuterium incorporation methods were applied to measure simultaneously cholesterol absorption and fractional synthesis, respectively. Plasma total cholesterol levels were lower in rabbits and hamsters fed 0.8 and 1% (w/w) SI, respectively, as compared to their controls. Percent cholesterol absorption was lower (P = 0.03) in hamsters fed 1% (w/w) SI (42.5 +/- 13.3%) than control (65.1 +/- 13.4%). Moreover, cholesterol excretion in the feces was 77 and 57% higher (P = 0.017) in the 1% (w/w) SI- relative to control- and 0.17% (w/w) SI-fed groups, respectively. In rabbits, cholesterol excretion was 64% higher (P = 0.018) in 0.8% (w/w) SI- compared with control-fed groups. Fractional synthesis rate was higher (P = 0.033) in hamsters fed 1% (w/w) SI (0.116 +/- 0.054 pool day(-1)) as compared to control (0.053 +/- 0.034 pool day(-1)). However, cholesterol synthesis rates did not vary among groups fed variable concentrations of SI. In rabbits, percent cholesterol absorption and its fractional synthesis rate varied but did not reach significance. Fractional synthesis rate in hamsters was correlated (r = -0.32, P = 0.03) with percent cholesterol absorption. In conclusion, dietary SI exhibited a dose-dependent action in inhibiting cholesterol absorption while increasing cholesterol excretion and upregulating cholesterogenesis in hamsters resulting in lower circulating lipid levels.     

肺癌CT普查--疾病分期与肿瘤大小的关系

目的：肺癌分期与肿瘤直径的关系已被证实是一个预后指标,因此被纳入1986年肺癌分类的国际系统。近年来由于CT飞速发展,人们可以诊断出更小的肺癌,于是有人提倡对肺癌Ⅰ期进一步分期,即根据肿瘤直径小于还是大于30mm,将无确切远处淋巴结转移的病例（Ⅰ期病例）细分为Ⅰa和Ⅰb期。在诊断无症状（即潜伏）的肺癌时,CT普查的开展使人们考虑肿瘤大小的预后价值。在此我们对CT普查诊断的无症状潜伏型肺癌作了分期与大小关系的报道。     

转化生长因子β1在大鼠纤维化腹膜组织中的表达及作用

目的:检测转化生长因子β1在腹膜透析大鼠腹膜内表达,并探讨其在腹膜纤维化中的意义。方法:实验于2005-06/2006-03在中南大学湘雅二医院肾内科实验室完成。①实验材料:雄性SD大鼠,体质量180～240g,由中南大学湘雅二医院动物实验中心提供。②实验方法:将28只大鼠按随机数字表随机分为4组,每组7只。正常对照组不予任何干预;生理盐水组腹腔注射20mL生理盐水;低糖透析液组腹腔注射20mL1.5%葡萄糖透析液;高糖透析液组腹腔注射20mL4.25%葡萄糖透析液,均为1次/d。4周后,向大鼠腹腔注射4.25%葡萄糖腹膜透析液20mL,4h后于大鼠右下腹缓慢插入带有多个侧孔的10号静脉留置针,缓慢低位引流腹透液,量取引流液。③实验评估:取大鼠壁层腹膜组织,以苏木素-伊红染色,镜下测量腹膜厚度,采用免疫组织化学方法检测大鼠腹膜中转化生长因子β1及纤连蛋白。结果:28只大鼠均进入结果分析。①高糖透析液组、低糖透析液组超滤量均明显低于正常对照组与生理盐水组,并且高糖透析液组超滤量明显少于低糖透析液组(P均<0.05)。②高糖透析液组腹膜明显增厚,表面粗糙,间皮细胞肿胀,脱落,间皮下有大量血管生成以及胶原纤维沉积,还可见单核细胞等炎症细胞浸润,与其他组比较,腹膜厚度明显增加(P<0.05)。③高糖透析液组转化生长因子β1、纤连蛋白表达量均明显高于其他组;低糖透析液组转化生长因子β1、纤连蛋白表达量均明显高于正常对照组与生理盐水组(P<0.05)。④大鼠腹膜组织转化生长因子β1蛋白与纤连蛋白表达量、腹膜厚度之间呈明显的正相关(r=0.86,0.83,P<0.05)。结论:葡萄糖透析液可诱导腹膜组织转化生长因子β1明显上调,腹膜转化生长因子β1高表达与腹膜透析腹膜纤维化密切相关。     

A healthy diet rich in carotenoids is effective in maintaining normal blood carotenoid levels during the daily use of plant sterol-enriched spreads

Blood cholesterol levels are affected by diet and in particular by the type and amount of fat intake. In recent years, vegetable oil spreads containing plant sterols/stanols (as their fatty acid esters) have been developed. Numerous clinical trials on spreads with added plant sterols/stanols have shown that they have much greater cholesterol-lowering properties than conventional vegetable oil spreads. Plant sterols decrease both dietary and biliary cholesterol absorption in the small intestine, with a consequential increase in excretion of cholesterol. It is also recognized that plant sterol/stanol-enriched, cholesterol-lowering spreads, if consumed regularly, may induce a 10-20% decrease in plasma carotenoids, adjusted for changes in plasma lipids. A 10-20% decrease in plasma carotenoids falls well within the seasonal variation observed in individuals. Our current understanding of the physiological functions of carotenoids does not indicate any health risk associated with the slight decrease in their blood levels due to the intake of plant sterol/stanol. The questions that have been raised, though, are how plant sterols/stanols affect plasma carotenoid levels, and in addition, what quantity of fruits and vegetables (the richest dietary sources of carotenoids) would have to be consumed to improve plasma carotenoid levels? The current mini-review covers the cholesterol-lowering effect of plant sterols, their mechanisms of action and effect on blood carotenoids, and concludes with the potential heath benefits of daily intake of plant sterol-enriched spreads.     

Long-term compliance and changes in plasma lipids, plant sterols and carotenoids in children and parents with FH consuming plant sterol ester-enriched spread

OBJECTIVE: To study the compliance and changes in plasma lipids, plant sterols, fat-soluble vitamins and carotenoids in children and parents with familial hypercholesterolemia (FH) consuming a plant sterol ester-enriched (PSE) spread. DESIGN: A 26-week open-label follow-up of children who had previously been studied in a controlled cross-over design. The parents were also included in the open-label arm of the study. SETTING: Outpatient clinic for treatment of hyperlipidemia. SUBJECTS: A total of 37 children (7-13 y) and 20 parents (32-51 y) diagnosed with 'definite' or 'possible' heterozygous FH. In all, 19 of the parents, but no children, used statins. All were patients at the Lipid Clinic, National Hospital in Oslo. INTERVENTIONS: Subjects were recommended to eat 20 g/day of PSE spread as part of their lipid-lowering diet. RESULTS: The mean intake of PSE spread was 13.7 and 16.5 g/days in the children and parents, respectively, corresponding to 1.2 and 1.5 g of plant sterols. Plasma total cholesterol decreased by 9.1% in both children (P<0.001) and parents (P=0.002). The corresponding decreases in LDL cholesterol were 11.4% (P<0.001) and 11.0% (P=0.012). Increases in serum lathosterol, campesterol and sitosterol, adjusted for total cholesterol, were observed in the children (31, 96, 48%, respectively, P<0.001) at the end of the controlled cross-over period. In the parents, serum campesterol and sitosterol, adjusted for total cholesterol, increased by 92 and 39%, respectively (P< 0.001). Lipid-adjusted serum alpha- and beta-carotene decreased by 17.4% (P=0.008) and 10.9% (P=0.018), respectively, in the children at the end of the controlled PSE period, but increased again during the follow-up. In the parents, serum alpha- and beta-carotene concentrations were unchanged, while serum lutein and lycopene decreased by 7.3% (P=0.037) and 14.6% (P=0.044), respectively. CONCLUSIONS: Sustained efficacy of cholesterol reduction and long-term compliance of PSE intake were demonstrated in this study.     

Cholesterol-lowering efficacy of a sitostanol-containing phytosterol mixture with a prudent diet in hyperlipidemic men.

BACKGROUND: Dietary plant sterols (phytosterols) have been shown to lower plasma lipid concentrations in animals and humans. However, the effect of phytosterol intake from tall oil on cholesterol and phytosterol metabolism has not been assessed in subjects fed precisely controlled diets. OBJECTIVE: Our objective was to examine the effects of sitostanol-containing phytosterols on plasma lipid and phytosterol concentrations and de novo cholesterol synthesis rate in the context of a controlled diet. DESIGN: Thirty-two hypercholesterolemic men were fed either a diet of prepared foods alone or a diet containing 1.7 g phytosterols/d for 30 d in a parallel study design. RESULTS: No overall effects of diet on total cholesterol concentrations were observed, although concentrations were lower with the phytosterol-enriched than with the control diet on day 30 (P < 0.05). LDL-cholesterol concentrations on day 30 had decreased by 8.9% (P < 0.01) and 24.4% (P < 0.001) with the control and phytosterol-enriched diets, respectively. HDL-cholesterol and triacylglycerol concentrations did not change significantly. Moreover, changes in circulating campesterol and beta-sitosterol concentrations were not significantly different between phytosterol-fed and control subjects. In addition, there were no significant differences in fractional (0.091 +/- 0.028 and 0.091 +/- 0.026 pool/d, respectively) or absolute (0.61 +/- 0.24 and 0.65 +/- 0.23 g/d, respectively) synthesis rates of cholesterol observed between control and phytosterol-fed subjects. CONCLUSION: Addition of blended phytosterols to a prudent North American diet improved plasma LDL-cholesterol concentrations by mechanisms that did not result in significant changes in endogenous cholesterol synthesis in hypercholesterolemic men.     

颈动脉损伤大鼠新生内膜增生与局部平滑肌细胞的增殖

目的:观察大鼠颈动脉损伤后高同型半胱氨酸血症对新生内膜形成和局部炎症因子单核细胞趋化因子1、细胞间黏附分子1表达及局部平滑肌细胞增殖的影响。方法:实验于2004-10/2005-02在北京大学第一临床医院心血管研究所完成。①Wistar雄性大鼠50只,采用随机数字法分为蛋氨酸组:1g/(kg·d)L-蛋氨酸灌胃;对照组:饮用水灌胃,每组25只。4周后检测两组血浆同型半胱氨酸浓度,并行左颈动脉球囊拉伤,分别于3,7,14,28d取材,检测血管损伤后新生内膜增生和局部单核细胞趋化因子1、细胞间黏附分子1表达情况。结果:①两组大鼠血浆同型半胱氨酸浓度:蛋氨酸组血浆同型半胱氨酸浓度明显高于对照组[(106.19±19.75),(4.90±0.10)μmol/L]。②两组大鼠血管组织形态学观察结果:苏木精-伊红染色血管损伤后7d可见内膜增生,14,28d蛋氨酸组新生内膜增生厚度比对照组增加36%,33%;新生内膜面积增加41%,30%;内膜面积/中膜面积增加36%,21%;管腔面积减少47%,61%;两组间比较差异均有显著性,但中膜面积无显著性差别。蛋氨酸组14d血管内膜和中膜平滑肌细胞中增殖细胞核抗原阳性颗粒百分比是对照组的1.7倍和2.3倍[(84.40±9.05)%比(49.00±4.51)%,P<0.01;(53.30±5.25)%比(23.70±6.17)%,P<0.01]。未损伤的右颈总动脉两组血管内膜及中膜增殖细胞核抗原阳性颗粒数小于0.1%。蛋氨酸组血管损伤局部单核细胞趋化因子1、细胞间黏附分子1表达增强,单核细胞趋化因子1主要分布在新生内膜和中膜,细胞间黏附分子1主要分布在内皮下和新生内膜,3d,7d明显,持续28d。结论:高同型半胱氨酸血症上调血管损伤局部炎症因子单核细胞趋化因子1、细胞间黏附分子1表达,促使局部平滑肌细胞增殖,使新生内膜增生。     

应用等离子体技术聚合制备-NH_2生物膜对大鼠卵巢细胞亲和性的影响

目的：以丙稀胺为单体,在RF脉冲等离子体条件下聚合制备含氨基的功能薄膜-NH2生物膜,观察应用等离子体技术进行材料表面改性后对卵巢细胞的细胞黏附、增殖及功能状态的影响。 方法：实验于2006-11/2007-04在首都医科大学生殖医学研究中心完成。①以丙稀胺为反应单体,利用等离子体处理仪器在盖玻片上聚合薄膜,制备-NH2生物膜基片。②覆有-NH2生物膜的基片为实验组;无覆膜的原始盖玻片为空白基片对照组。将P2代Wistar大鼠卵巢细胞分别接种于两组基片上,在37℃、体积分数为0.05的CO2培养箱中培养。③分别于培养12h和24h两个时间点取样检测。测量基片上细胞黏附面积,计算出百分率,反映细胞黏附率;利用MTT微量酶反应比色法测定MTT代谢率,反映细胞活性;采用放射免疫法检测培养液中雌二醇质量浓度,反映卵巢细胞分泌功能。 结果：①-NH2生物膜基片上卵巢细胞的黏附率12h和24h分别为61%,100%,明显高于空白基片上卵巢细胞细胞黏附率47%,78%。②-NH2生物膜基片上卵巢细胞MTT代谢率明显高于对照组（P〈0.01）。③-NH2生物膜基片培养液中雌二醇质量浓度也明显高于空白基片（P〈0.01）。 结论：应用等离子体技术进行表面改性后的-NH2生物膜在较短的时间内对体外培养的大鼠卵巢细胞的黏附、体外存活和分泌功能有明显的促进作用,对大鼠卵巢细胞具有细胞亲和性。