中链脂肪酸与脂代谢

过去临床一直强调：降低每日膳食总能量、总脂肪、胆固醇、饱和脂肪及反式脂肪酸摄入量是降低血三酰甘油、胆固醇,以及预防动脉粥样硬化的有效措施之一。但近年来研究发现,膳食中脂肪酸的种类和组成同样起重要作用。中链脂肪酸（ medium-chain fatty acids, MCFAs）为含有8～12个碳原子的饱和脂肪酸,常见为辛酸（C8∶0）和癸酸（C10∶0）,自然界主要来源于母乳、牛奶及其制品、棕榈仁油和椰子油等。 MCFAs和甘油通过酯化作用形成中链三酰甘油（medium-chain triglycerides,MCT）,MCT中辛酸和癸酸的比例多在50∶50～80∶20范围,与长链三酰甘油（ long-chain triglycerides , LCT ）相比,它进入体内后可快速代谢氧化提供能量,且不易在组织器官储存,因而能减少脂肪组织的富集。20世纪50年代,MCT应用于临床治疗包括胰腺功能不全、脂质吸收障碍、淋巴运输系统障碍及长链脂肪酸（long-chain fatty acids, LCFAs）氧化缺陷的患者［1］。目前,MCT已经作为营养支持的重要组成之一,应用于胆囊纤维化、高脂血症、癫症、腹泻和脂肪吸收不良等相关性疾病的治疗。越来越多的研究显示,MCT可改善机体代谢紊乱或症状,对脂代谢具有重要的调节作用,具有防治高脂血症及心血管疾病发生的作用,笔者就MCFAs对脂代谢的影响及其机制的研究进展作一介绍。     

飞行员高三酰甘油应答诱导胰岛素抵抗现象

目的 探讨脂肪负荷餐后高三酸甘油应答诱导胰岛素抵抗及其与动脉粥样硬化的关系。方法 50名飞行员分为试验组和对照组(各25名)。试验组食脂肪负荷餐.分别于空腹,餐后3、8h采血;对照组不食脂肪负荷餐,采血时间同试验组。测定3个时间点血浆三酰甘油、血糖和胰岛素水平,计算胰岛素敏感指数。结果 试验组富含三酰甘油的脂蛋白清除延迟发生率4/25。4名富含三酰甘油脂蛋白清除延迟者餐后3h胰岛素敏感指数低于试验组餐后3h均值。试验组在餐后3h高三酰甘油应答的同时胰岛素敏感指数降低,与两组空腹及对照组3h相比差异有显著性意义。结论 高三酰甘油应答或富含三酰甘油脂蛋白清除延迟诱导胰岛素抵抗可能是产生这一现象的直接原因。     

内脂素与肥胖及运动关系研究进展

<正>肥胖是指体内脂肪细胞数目增多或体积增大,脂肪(主要是三酰甘油)堆积过多,使体重超过标准体重20%以上的病理状态[1]。随着对其发病机理和抗肥胖治疗研究的不断深入,人们发现脂肪组织不仅仅是能量贮存的场所,而且是一个重要的内     

蛋白激酶C和环磷酸腺苷在胃癌细胞凋亡中的变化特点及意义

在细胞信号多条传导通路中,蛋白激酶Ａ环磷酸腺苷（ＰＫＡｃＡＭＰ）和二酰基甘油蛋白激酶Ｃ（ＤＧＰＫＣ）是研究较为清楚的２条通路［１］。而ｃＡＭＰ和ＰＫＣ是这２条信号传导通路中重要的信号分子,它们广泛参与细胞的信息传递和肿瘤细胞的生长、分化、增殖等过程。本实验用顺铂诱导胃癌细胞凋亡,动态观察其细胞凋亡过程ｃＡＭＰ和ＰＫＣ的变化特点,探讨胃癌细胞凋亡的信号传导机制。材料与方法一、试剂ＲＰＭＩ１６４０为美国ＬｉｆｅＴｅｃｈ公司生产;顺铂为山东齐鲁制药厂生产;碘化丙啶、ＲＮＡ酶、磷脂酰丝氨酸（ＰＳ…     

飞行员脂肪负荷餐后性激素改变分析

目的：探讨飞行员脂肪负荷餐后性激素水平的改变及其与动脉粥样硬化的关系。方法：将飞行员50例随机分为观察组与对照组各25例。观察组给予脂肪负荷餐,对照组给予正常饮食。在脂肪负荷餐前、餐后3h和8h分别采血,用放射免疫法测定血浆睾酮（T）、雌二醇（E2）、垂体泌乳素（PRL）、促黄体生成激素（LH）和促卵泡激素（FSH）等5项性激素水平,分析其动态变化规律。结果：观察组脂肪负荷餐后高三酰甘油（TG）反应和（或）三酰甘油丰富脂蛋白（TRL）清除延迟,引起血浆T水平降低、B水平升高,与对照组比较,差异显著（P〈0．05）。观察组T／E2比值降低、失衡,且失衡时限长于TG恢复正常时限;对照组无显著变化。结论：飞行员脂肪餐后高TG反应和（或）TRL清除延迟是导致血浆T／E2比值降低和失衡的直接原因,可能与动脉粥样硬化发生发展有关。     

运动与肉碱棕榈酰转移酶-Ⅰ研究进展

脂酰CoA向线粒体基质的转运是β氧化的限速环节,其中起关键作用的是肉碱脂酰转移酶。肉碱脂酰转移酶是一族酶,它包括肉碱乙酰基转移酶(CAT)、肉碱辛酰基转移酶(COT)和肉碱棕榈酰转移酶(CPT)。三种肉碱脂酰转移酶有选择地催化不同碳链长度的底物[1]。长链脂酰CoA(C10-C18)是CPT-     

急性胰腺炎伴高三酰甘油血症的临床特点

目的：探讨高三酰甘油血症对急性胰腺炎（AP）临床表现及其脏器功能的影响。方法：2004—04—2006—12我院共收治491例AP，按三酰甘油水平高低分为血脂正常组、血脂增高组、高脂血症性胰腺炎（HLP）组，分析其临床特点、并发症、平均住院日、病死率等。结果：血淀粉酶、血钙随三酰甘油水平增高而下降（P〈0．05或P〈0．01）；而血糖、CHP、APACHEⅡ评分明显升高（P〈0．05）；平均住院日延长（P〈0．05）；胸腹腔积液发生率增高（P〈0．05和P〈0．01）；当三酰甘油〉5．65mmol／L时，急性肺损伤、急性肾衰竭、休克发生率明显增加（P〈0．05），并且病死率增加（P〈0．05）；肠麻痹或肠梗阻发生率在三酰甘油增高时显示增加趋势，但差异无显著性（P〉0．05）。结论：临床诊断中应注意三酰甘油水平增高时，常不伴血淀粉酶的显著升高。诊治早期应警惕重症化倾向。高三酰甘油血症可增加并发症发生率及病死率。     

Exendin-4皮下给药对减重的效果

 目的研究Exendin-4(胰高血糖素样肽-1受体激动剂)短期皮下给药的减重效果.方法将40只6～8周龄Wistar大鼠,随机分成4组,分别皮下注射0、1、5、25 μg/kg exendin-4,连续13周,记录体重、摄食量,并进行血清胆固醇、三酰甘油检测,测定腹膜后肾周围脂肪重量和细胞大小.结果用药后大鼠体重增长缓慢,腹膜后肾周围脂肪重量较对照组降低,血清中三酰甘油降低,而摄食量、血清胆固醇、脂肪细胞大小不受药物的影响.结论Exendin-4短期皮下给药,具有明确的延缓体重增长的效果,其作用机制可能是通过抑制脂肪细胞的增殖.     

甘油氧化酶法测定血清三酰甘油的研究

目的:建立一种甘油氧化酶法测定血清三酰甘油新法。方法:用脂蛋白脂酶、甘油氧化酶和3-甲基-N-乙基(β-羟乙基)苯胺(简称MEHA)色原系统进行血清三酰甘油测定。结果:对最适缓冲液浓度、pH和种类的选择,提高了灵敏度,线性范围为0～18 mmol/L,正常参考范围为男0.05～1.80 mmol/L、女0.04～1.70 mmol/L。其回收率为93%～103%,精密度:批内(n=20)CV=2.6%～4.2%,批间(n=20)CV=3.1%～4.8%,与酶(GPO-PAP)法比较,相关性良好(γ=0.982)。结论:本法具有高度的特异性和准确性,操作简便、灵敏快速、标本用量少、结果稳定可靠,是一种新的三酰甘油测定法。     

高三酰甘油的高血压病人空腹胰岛素的变化

三酰甘油 (甘油三酯 )水平增高是老年人高血压病常见的血脂代谢异常。为了解高三酰甘油高血压病病人的空腹胰岛素变化情况 ,我们比较了高三酰甘油血症与三酰甘油正常的高血压病人空腹胰岛素、其他代谢因素和心肌损害等方面的差异。1　对象和方法1 1　对象　选择老年 (6 0岁以上 )高血压病病人 ,排除继发性高血压、心瓣膜病变、肥厚性心肌病、心功能不全、肝肾功能不全和糖尿病病人 ,共 6 3例 ,其中男 33例 ,女 30例 ;平均年龄 6 0 79± 7 87岁 ,高血压病史 8 32± 6 6 0年 ,收缩压 2 3 0 2± 2 0 8ｋＰａ ,舒张压 13 4 7± 1 0 5ｋＰａ ,…     

Exercise and postprandial plasma triacylglycerol concentrations in healthy adolescent boys

PURPOSE: Atherosclerosis is initiated in childhood. Therefore, reducing postprandial triacylglycerol concentrations ([TAG]), even in young people, could potentially slow atherogenic progression. This study investigated whether continuous-exercise and intermittent-games activity would reduce postprandial [TAG] in adolescent boys. METHODS: Nineteen subjects were randomly assigned to either a continuous-exercise group (N = 10) or an intermittent-games group (N = 9) and underwent two 2-d trials. Trials were performed a minimum of 7 d apart in a randomized order, consisting of a rest trial and either a continuous-exercise or intermittent-games trial. In the rest trial, subjects took no exercise on day 1. On day 1 of the exercise trial, subjects completed four blocks (approximately 15 min each) of uphill treadmill walking or intermittent-games activity with 3 min of rest between each block. On day 2, subjects came to the laboratory after an overnight fast, and finger-prick blood samples were obtained in the fasted state. Subjects then consumed a test meal (1.25 g of fat, 1.07 g of carbohydrate, 0.20 g of protein, and 67 kJ.kg(-1) body mass). Further blood samples were collected at 30 and 45 min and at 1, 3, 4, and 6 h postprandially. RESULTS: The total area under the plasma [TAG] versus time curve was lower on day 2 after exercise than the rest condition in both groups (Student's t-tests for correlated means: continuous-exercise group 14%, P = 0.050; intermittent-games group 26%, P = 0.002). CONCLUSION: Both continuous-exercise and intermittent-games activity reduce [TAG] in healthy adolescent boys when performed the afternoon before ingesting a high-fat meal.     

Increased postprandial triacylglycerol concentrations following resistance exercise

PURPOSE: There is conflicting evidence whether a single bout of resistance exercise performed the day before a test meal can lower postprandial triacylglycerol (TAG) concentrations. The present study examined the effect of a single session of resistance exercise, performed the same day as a test meal, on postprandial TAG concentrations in resistance-trained males. METHODS: Ten healthy males aged 25 (SD 2.6) yr performed two trials at least 1 wk apart in a counterbalanced, randomized design. In each trial, participants consumed a test meal (0.89 g of fat, 1.23 g of carbohydrate, 0.4 g of protein, 60 kJ.kg body mass). Before one meal, participants performed a 90-min bout of resistance exercise. Before the other meal, participants were inactive (control trial). Resistance exercise was performed using free weights and included three sets of 12 repetitions of each of 10 exercises. Sets were performed at 80% of 12-repetition maximum with a 3-min work and rest interval. Venous blood samples were obtained in the fasted state and for 5 h postprandially. RESULTS: Total area under the plasma TAG concentration versus time curve was higher (Student's t-test P = 0.008) on the exercise than control trial (mean +/- SE: 11.76 +/- 1.64 vs 7.94 +/- 1.08 mmol x L(-1) x 5 h(-1), respectively). Total area under the plasma myoglobin concentration versus time curve was higher (Student's t-test P = 0.010) on the exercise than control trial (16.68 +/- 3.34 vs 6.80 +/- 0.64 nmol x L(-1) x 5 h(-1); respectively). CONCLUSION: A single bout of resistance exercise can cause a transient elevation in postprandial TAG concentrations. The elevations in plasma myoglobin suggest postexercise muscle damage. Further investigation is needed to see if these findings are linked.     

Factor XIIa and triacylglycerol rich lipoproteins: responses to exercise intervention

OBJECTIVES: (a) To determine if factor XIIa (FXIIa) would be sensitive to change from exercise intervention in a group of previously sedentary/low active middle aged men and women; (b) to investigate further the previously reported relation between FXIIa and triacylglycerol (TAG) rich lipoproteins. METHODS: Thirty seven men (mean (SD) age 57 (7) years) and 60 women (mean age 54 (7) years) completed the study. Before the intervention, these subjects were randomly allocated to a group of walkers (n = 81) or controls (n = 16). Before and after an 18 week walking intervention, fasted blood samples were collected and analysed for FXIIa, TAG, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and apolipoprotein (apo) B. RESULTS: Kruskal-Wallis analysis of data obtained before the intervention showed no significant differences (p>0.4) between the walking and control groups for age, height, body mass, gender, FXIIa, TAG, TC, HDL-C, or apo B, although the women did show significantly lower levels of TAG (p<0.04) and higher HDL-C (p<0.0001) than the men. General linear model analysis of data obtained after the intervention, using the baseline value as a covariate, showed significant reductions (p<0.0001) in FXIIa for the walkers compared with the controls. Pearson product-moment correlations also showed significant relations between the concentrations of FXIIa and TAG, TC, LDL-C, and apo B. CONCLUSIONS: The findings of this study suggest that FXIIa is sensitive to change from exercise intervention and support previous research showing an association between the concentrations of FXIIa and TAG rich lipoproteins.     

Postprandial triacylglycerol in adolescent boys: a case for moderate exercise

PURPOSE: To compare the effects of 60-min bouts of intermittent moderate and vigorous exercise on postprandial plasma triacylglycerol (TAG) metabolism in eight healthy adolescent boys (mean +/- SD age: 13 +/- 0.3 yr). METHODS: Participants completed three conditions in a counterbalanced order. On day 1, they either rested for 110 min (CON), completed 6 x 10-min blocks of intermittent treadmill exercise at 53% peak V O2 (MOD), or 6 x 10-min blocks at 75% peak V O2 (VIG). On day 2 after a 12-h fast, a capillary blood sample was taken for [TAG] and [glucose] (mmol.L) and then a high-fat milkshake was consumed (1.50 g.kg fat, 1.22 g.kg CHO, and 0.22 g.kg protein; 80 kJ.kg). Further blood samples were taken every hour for a 6-h postprandial rest period for [TAG] and [glucose]. RESULTS: Estimated energy expenditure was 45% higher in VIG than in MOD (95% confidence interval [CI] 23-72%). Fasting [TAG] and [glucose] did not differ between the conditions. Average [TAG] for the postprandial period was lower by 24% in MOD (95% CI -47% to 9%, P = 0.06) and by 21% in VIG (95% CI -42% to 8%, P = 0.08) than CON, with no meaningful difference (4%; 95% CI -27% to 48%, P = 0.50) between MOD and VIG. The total area under the [TAG] versus time curve (mmol.L 6 h) was lower by 24% in MOD (95% CI -42% to 0%, P = 0.05) and by 20% in VIG (95% CI -37% to 0%, P = 0.07) than CON. MOD and VIG were not different from each other (4%; 95% CI -18% to 32%, P = 0.54). CONCLUSION: Both 60 min of moderate and vigorous intermittent exercises reduced postprandial [TAG]. However, the extra energy expended in the vigorous condition did not produce a dose-related reduction compared with the moderate-intensity condition.     

Physical training improves insulin resistance syndrome markers in obese adolescents

INTRODUCTION: The purpose of this study was to test the hypothesis that physical training (PT), especially high-intensity PT, would have a favorable effect on components of the insulin resistance syndrome (IRS) in obese adolescents. METHODS: Obese 13- to 16-yr-olds (N = 80) were randomly assigned to one of the following 8-month interventions; 1) lifestyle education (LSE)-alone every 2 wk, 2) LSE+moderate-intensity PT, and 3) LSE+high-intensity PT. PT was offered 5 d x wk(-1). Plasma triacylglycerol (TAG), total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), very low-density lipoprotein cholesterol (VLDLC), low-density lipoprotein cholesterol (LDLC), low-density lipoprotein (low density lipoprotein (LDL)) particle size, apolipoproteins AI and B, glucose, insulin, and blood pressure were measured with standardized methods. RESULTS: The intent-to-treat analyses for all subjects who completed pre- and post-tests regardless of their adherence to the interventions showed that the LSE+high-intensity PT group had more favorable changes than the LSE-alone group in TAG level (P = 0.012), TC/HDLC (P = 0.013), and diastolic blood pressure (P = 0.031). For efficacy analyses, all PT subjects who attended at least 2 d x wk(-1) (40%) were combined into one group (LSE+PT) and compared with the LSE-alone group. These two-group analyses showed significant interactions (P < 0.001) between baseline values and group membership for deltaTAG, deltaVLDLC, and deltaTC/HDLC, such that subjects who had the least favorable baseline values showed the most beneficial impact of the PT. Of particular interest was a favorable effect of the PT on LDL particle size. CONCLUSION: PT, especially high-intensity PT, had a favorable effect on several IRS markers in obese adolescents.     

Effects of intermittent games activity on postprandial lipemia in young adults

PURPOSE: To investigate whether a single session of intermittent games activity would reduce postprandial lipemia. METHODS: Twelve male volunteers completed three 2-d trials: rest, continuous exercise, and intermittent games activity. Trials were performed a minimum of 6 d apart in a balanced crossover design. In the rest trial, subjects took no exercise on day 1. On day 1 of the continuous and intermittent games trials, subjects completed four blocks (approximately 15 min per block) of uphill treadmill walking or intermittent games activity with 3 min of rest between each block. On day 2, subjects came to the laboratory for an oral fat tolerance test (blood taken fasted and for 6 h following a high-fat test meal (1.25 g of fat and 1.07 g of carbohydrate per kilogram of body mass)). RESULTS: The intermittent games protocol elicited a higher exercise intensity than the continuous trial (lactate: 4.3+/-0.6 vs 2.4+/-0.3 mmol.L; % VO2max: 72+/-2 vs 62+/-1, respectively; mean+/-SE). The total area under the plasma triacylglycerol (TAG) concentration versus time curve was lower in both the intermittent games (25%, P=0.001) and the continuous (19%, P=0.028) trials than in the rest trial. CONCLUSION: These findings show for the first time that intermittent games activity can reduce postprandial lipemia, and confirm that continuous exercise reduces postprandial lipemia in young adults.     

Improved diagnostic performance of transluminal attenuation gradient in combination with morphological evaluation of coronary artery stenosis using 320-row computed tomography

Purpose

To assess the utility of transluminal attenuation gradient (TAG) in combination with coronary computed tomography angiography (CTA) for detecting obstructive coronary artery stenosis.

Materials and methods

We retrospectively evaluated coronary CTA data in 35 consecutive patients who underwent invasive coronary angiography (ICA). We compared the diagnostic performance of TAG with that of quantitative coronary angiography, which we used as the reference standard. For the combination of TAG and coronary CTA, we designed a logical conjunction model (CCTA&&TAG) as well as a logical disjunction model (CCTA||TAG), and evaluated their diagnostic accuracies.

Results

Among 130 vessels of 35 patients, 30 lesions (23%) showed significant stenosis on ICA. TAG predicted significant coronary artery stenosis with a sensitivity of 75%, specificity of 63%, positive predictive value of 40%, negative predictive value of 89%, and accuracy of 66%, and had a cutoff value of ? 15.4 HU/10 mm. The respective values for CCTA&&TAG were 73, 98, 88, 90, and 90%; those for CCTA||TAG were 94, 61, 56, 94, and 72%. CCTA&&TAG improved the diagnostic accuracy significantly more than CCTA||TAG.

Conclusion

TAG in conjunction with coronary CTA improves the diagnostic accuracy of coronary CTA.

     

血红素加氧酶-1与肾脏损伤

血红素加氧酶-1(HO-1)作为哺乳动物降解血红素的主要途径之一,其主要降解产物——一氧化碳(CO)、自由铁(Fe2+)和胆绿素——在促进细胞生存、细胞内物质循环及免疫调节中具有重要作用。既往研究提示血红素-HO-1通路是决定急性肾损伤(AKI)易感性及严重性的重要内在因素。诱导HO-1表达能够减轻肾脏缺血-再灌注损伤(IRI)的严重程度,而抑制HO-1的表达会加重IRI。本文综述了国内外有关HO-1在AKI诱导保护机制方面的最新研究进展,以便深入认识HO-1在AKI治疗中的作用。     

Order effects of high-intensity intermittent and strength exercise on lipoprotein profile

Purpose

To compare the effects of the order of concurrent exercise (endurance plus strength or strength plus endurance) on lipoprotein profiles in men.

Methods

After the evaluation of maximum strength (one repetition maximum—1RM) in the half-squat and of aerobic fitness (maximal velocity in treadmill incremental test), 11 physically active male subjects underwent two randomized sessions composed of four sets of half-squat strength exercises until exhaustion (at 80 % of 1RM) and a 5-km run high-intensity intermittent exercise (1:1 min at V _max), performed in different orders: (1) strength plus run (S-A) and inverse order, and run plus strength (A-S). Blood samples were collected before and immediately after the first exercise (Post-1) and after the second exercise (Post-2) in the intra-session sequence. Serum was analyzed for total cholesterol (TC) and its ratio, HDL-c and LDL-c, and triacylglycerol (TAG).

Results

There were effects of condition for TC, LDL-c, and TC/HDL, with greater values in the AS than SA (p < 0.001 for all). For the delta analysis, there was an interaction effect for TAG, with greater delta-1 S-A than delta-1 A-S (p = 0.035), and higher delta-1 S-A than delta-2 S-A (p = 0.001); for LDL-c, with higher delta-1 S-A values than delta-2 S-A (p = 0.010); and for TC, with higher delta-1 S-A values than delta-2 S-A (p = 0.038).

Conclusion

We conclude that there are no differences between the order of acute high-intensity intermittent run plus strength exercises regarding modulation of the lipoprotein profile in healthy, physically active men.