小肠吸收胆固醇的分子生物学研究进展

胆固醇通过分布于十二指肠和近段空肠黏膜上皮细胞刷状缘膜的Niemann—Pick C1样蛋白1摄取，ATP结合盒G5、G8抑制小肠对胆固醇的摄取过程。进入上皮细胞的胆固醇大多数被乙酰辅酶A，胆固醇转乙酰基酶2酯化，随后通过组装形成乳糜微粒，经淋巴管进入血循环；另一部分胆固醇则以未酯化形式直接进入血循环形成高密度脂蛋白颗粒。这些过程受核受体——肝脏X受体的调控。年龄、性别、黏膜屏障和小肠传输速度也影响胆固醇的吸收。     

Cholesterol screening: observed cholesterol reduction in a prospective study in Norway

The general public of the City of Bergen, Norway was Invitedto participate in a cholesterol screening programme in October1988. Participants received the results of the cholesterol screeningand nutritional information from trained health personnel. Ashort questionnaire was mailed to all 354 participants 1–2weeks after the initial cholesterol screening. In March 1990,all participants were invited to have their cholesterol levelsre-examined. Psychosocial factors believed to be predictiveof future serum cholesterol changes were assessed at baselinealong with demographic variables. The majority of participants(61%) reduced their cholesterol level from October 1988 to March1990, and the average reduction in cholesterol level for thetotal population was 4.0%. Baseline cholesterol levels, beingconfident of one's own ability to change one's diet (self-efficacy),seeing heart disease risk reduction as very important, and maritalstatus were factors that significantly predicted successfulcholesterol reduction 18 months later.     

人红细胞胆固醇含量的增龄变化

用胆固醇酶联试剂显色法检测１８９例健康成人红细胞胆固醇和血浆胆固醇含量，结果表明，健康成人的Ｅ－Ｃｈ含量随增龄而升高，并呈直线相关；Ｐ－Ｃｈ含量也随增龄而升高，并呈直线相关；Ｅ－Ｃｈ含量呈直线正样关。提示Ｅ－Ｃｈ含量检测可作为反映机体衰老程度的一项客观指标。     

伤湿胶囊抗炎镇痛作用的实验研究

为评价伤湿胶囊的抗炎镇痛功效，采用蛋清致大鼠足跖浮肿法、二甲苯致小鼠耳肿胀法、硫酸组胺致小鼠皮肤毛细血管通透性法、大鼠棉球肉芽肿法、小鼠热板法及醋酸扭体法，观察伤湿胶囊的抗炎、镇痛作用，并与伤湿丸比较；用改良Zak法测定小鼠肾上腺中胆固醇含量，结果显示伤湿胶囊对大鼠足肿胀、小鼠耳肿胀及皮肤毛细血管通透性均有显著抑制作用，可明显提高小鼠热板法致痛的痛闷，减少醋酸致痛小鼠的扭体次数，其效果比伤湿丸好；测得小鼠肾上腺中的胆固醇含量明显降低，对大鼠棉球肉芽肿无明显抑制作用，说明伤湿胶囊对急性炎症有较好的抗炎作用和镇痛作用，疗效优于伤湿丸组；对慢性炎症无明显的抑制作用，其抗炎机理初步认为与兴奋肾上腺皮质有关。     

Role of Isoflavones in the Hypocholesterolemic Effect of Soy

Epidemiologic data suggest an inverse relationship between the consumption of soy isoflavones and cardiovascular disease risk. The aims of this review are to determine if isoflavones play a role in the hypocholesterolemic effect of soy and whether the studies realized with that scope were adequately designed. In humans, most studies have been performed in postmenopausal women. The results are inconsistent, however; some studies show a decrease in total cholesterol and low-density lipoprotein concentrations, and an increase in high-density lipoprotein levels, and other investigations fail to show any beneficial effect of soy isoflavones on lipid profiles. In most studies, beneficial effects could not be attributed with certainty to soy isoflavones. If these components have any health-protecting effect in humans, it is small in comparison with the effect of soy protein itself. There are currently not enough data to recommend the consumption of isoflavone supplements to lower plasma cholesterol levels.     

The distribution profiles of very low density and low density lipoproteins in poorly-controlled male,Type 2 (non-insulin-dependent) diabetic patients

Summary The distribution and composition of lipoproteins spanning the very low density and low density lipoprotein spectra have been analysed in ten poorly-controlled, male, Type 2 (non-insulin-dependent), diabetic patients pre-disposed to mild, secondary hypertriglyceridaemia. As compared to age-matched control subjects, the diabetic patients displayed grossly modified, distinctly atherogenic lipoprotein profiles. Modifications were not limited to the very low density lipoprotein profile, as would be expected from the pre-treatment hypertriglyceridaemia. There was also an aberrant low density lipoprotein profile, which was not evident from plasma cholesterol measurements, especially as the diabetic patients at entry were well matched to control subjects with respect to plasma levels of this lipid. Compositional abnormalities were also observed in the poorly-controlled diabetic group, although these were less marked than the distributional changes. There were substantial improvements of the abnormalities detailed above, even over a short treatment period (two weeks), with therapy designed primarily to ameliorate metabolic control. The data suggest that, in the presence of poor metabolic control and hypertriglyceridaemia, occult, atherogenic modifications of low density lipoproteins can occur. The results argue in favour of strict control of triglyceride levels even in diabetic patients with apparently acceptable cholesterol levels.     

AN EPIDEMIOLOGICAL SURVEY OF CHOLELITHIASIS IN SHANGHAI

Objective To obtain a general overview of gallstone disease in Shanghai. Methods 3415citizens aged >20 in the community of Shanghai were randomly selected to undergo a clinical epidemiological study and an ultrasound examination to screen for cholelithiasis. Results Overall prevalence rate of gallstones was 6.5% (8.6% in women and 5.1% in men). Among the 3415 persons investigated, 65 had already undergone cholecystectomy. The percentage of asymptomatic gallstone was 70 .5% . Prevalence of gallstone diseases (gallstones plus cholecystectomy) increased with age significantly. Conclusion Compared to the research in Shanghai ten years ago, especially for the persons older than 50 years, the gallstone disease has become more frequent. The proportion of asymptomatic gallstones and the awareness is increasing.     

Sevelamer hydrochloride with or without alphacalcidol or higher dialysate calcium vs calcium carbonate in dialysis patients: an open-label, randomized study.

BACKGROUND: Sevelamer hydrochloride was recently proposed as a phosphate binder to prevent hypercalcaemia in place of calcium alkaline salts in dialysis patients. So far, it has been evaluated only in patients receiving calcitriol, without comparison with CaCO(3) alone, although the latter was found to be as effective as the combination of calcitriol and Al(OH)(3) in suppressing parathyroid hormone (PTH) without inducing hypercalcaemia and to have a better lowering effect on serum phosphate. Moreover, this bile salt binder may decrease serum 25-OH vitamin D. Therefore, we compared for 5 months two strategies for controlling moderate hyperparathyroidism: CaCO(3) alone vs sevelamer in conjunction with measures to increase calcium balance. METHODS: Forty-two patients were randomized: 21 continued their treatment with 4.8 g/day CaCO(3) and 21 were switched to sevelamer (initial dose: 2.4 g/day, increased to 4.4 g/day). Each month, when serum-corrected calcium decreased below 2.30 mmol/l, dialysate calcium was increased or alphacalcidol was given at each dialysis session, according to serum PO(4) levels. The following parameters were monitored: serum Ca, PO(4), bicarbonate and protein, weekly; and serum PTH, 25-OH vitamin D and total, LDL and HDL cholesterol monthly. RESULTS: Except for higher serum phosphate at month 1, lower serum bicarbonate at month 2 and lower LDL cholesterol at month 5 in the sevelamer group, no difference was found between the two groups. Compared with baseline levels, PTH increased and 25-OH vitamin D decreased significantly in both groups, these two parameters being inversely correlated. CONCLUSIONS: Given comparable control of plasma calcium, phosphate and 25-OH vitamin D, PTH control is comparable in both strategies. Sevelamer does not induce greater vitamin D depletion than CaCO(3). The transient decrease of serum bicarbonate after discontinuation of CaCO(3) in the sevelamer group suggests a less optimal prevention of acidosis. The sevelamer-induced decrease in LDL cholesterol gives this drug a potential advantage in cardiovascular prevention.     

氧化胆固醇对动脉毒性作用的研究

将Wistar大鼠随机分成氧化胆固醇组(Och)、纯胆固醇组(Pch)和对照组,分别用氧化胆固醇混合物(250mg/kg bw/d)、纯胆固醇(250mg/kg bw/d)以及悬浮固醇用的明胶液体给大鼠灌胃,连续二天。于第二次灌胃后18小时,从大鼠尾静脉注射伊文思兰溶液,并于注射后2小时处死;取出主动脉用荧光显微分光光度术测定主动脉内膜的通透性。此外,另一部分动物在第二次灌胃后24小时处死,取出主动脉作扫描电镜的内膜观察。结果表明,Och大鼠主动脉内膜的通透性显著高于Pch组与对照组大鼠(P<0.01),而Pch组大鼠主动脉内膜的通透性和对照组无显著差异(P>0.05)。     

Brevibacterium sp.DGCDC-82发酵罐中生产胆固醇氧化酶

用Brevibacterium sp.DGCDC-82在7L发酵罐中分批培养.分别对添加剂吐温-80、培养温度、培养基的pH、通风量和搅拌速度在胆固醇氧化酶的生产中的影响进行了研究.结果显示以上条件均对产酶有影响.在不同的发酵阶段改变发酵操作条件,发酵20 h最高酶活可达1203U/L,生产强度可达60 U/(L·h).既有效地提高了胆固醇氧化酶的产量,又防止了发酵过程中的泡沫外溢.