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。     

飞行员脂肪耐量调查

目的探讨飞行员脂肪负荷餐后富含甘油三酯的脂蛋白(TRL)清除延迟发生率,TRL清除延迟与血浆高密度脂蛋白胆固醇(HDL-C)、纤维蛋白原(FIB)及一氧化氮(NO)的关系.方法62名飞行员作为调查对象,测定其空腹12h后和服黄油试验餐(黄油量1.3g/kg体重)后血浆甘油三酯(TG)、HDL-C、FIB和NO水平.结果62名飞行员TRL清除延迟发生率为43.5%,其餐后8hTG水平平均为空腹的2.5倍,差异有显著性意义(P＜0.01);FIB水平升高(P＜0.01)HDL水平下降(P＜0.05);餐后8h血浆NO水平与空腹水平差异无显著性意义(P＞0.05).结论飞行员脂肪负荷餐后TRL清除延迟发生率明显高于招飞学员的发生率(5%).血浆高HDL-C水平可能具有抗TRL清除延迟的作用.应注意TRL清除延迟与低HDL-C、高FIB血症等致动脉粥样硬化危险因素的综合防治.     

普萘洛尔和恬尔心对脂蛋白代谢的影响

用体外培养人脐静脉内皮细胞单层(EC)观察普茶洛尔、恬尔心对脂蛋白代谢的影响.将等量的高脂蛋白血清分别与两药混合后加于内皮细胞单层培养基上孵化10h,取培养上清液检测甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)、极低密度脂蛋白(VLDL).结果显示:普茶洛尔显著降低LDL水平(P<0.01),对脂蛋白代谢产生有益影响.恬尔心显著降低TG水平(P<0.05),同时亦降低HDL水平(P<0.01),其对脂蛋白代谢的作用尚难评估.     

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。     

健康老年男性脂肪负荷餐后雄激素水平的改变

 目的探讨健康老年男性富含三酰甘油脂蛋白(TRL)清除延迟与性激素水平改变的关系.方法与脂肪耐量试验同时采集空腹、脂肪负荷餐后(餐后)3 h、8 h静脉血.测定血浆三酰甘油(TG)、高密度脂蛋白-胆固醇(HDL-C)、总胆固醇(CHO)和血浆睾酮(T)、雌二醇(E2)、垂体泌乳素(PRL)、促黄体生成激素(LH)、促卵泡激素(FSH)动态变化水平.结果健康老年男性TRL清除延迟发生率7.8%.TRL清除延迟组较清除正常组基础T水平低、E2水平相对高(P＜0.01或P＜0.05).餐后高TG应答和(或)TRL清除延迟导致血浆T水平降低、E2水平升高(P＜0.01或P＜0.05),T/E2比值失衡.血浆PRL、LH、FSH改变差异无统计学意义(P＞0.05).结论 TRL清除延迟是致动脉粥样硬化的危险因素,也是导致健康老年男性T/E2比值失衡的直接原因,可能与动脉粥样硬化发生发展有关.     

吸烟对脑梗死患者尿液中8-异前列腺素F2α含量的影响

目的 探讨吸烟对脑梗死患者尿液中8-异前列腺素F2α(8-iso-PGF2α)含量的影响.方法 选取急性脑梗死患者28例,其中14例(有吸烟史)作为吸烟组,另外14例(无吸烟史)作为对照组,两组的年龄、性别、血压、血脂、血糖、病灶部位及脑梗死程度无显著性差异.用酶联免疫分析法测定所有受试者尿液中8-iso-PGF2α的浓度及空腹静脉血中低密度脂蛋白(LDL) 总胆固醇、LDL三酰甘油、LDL游离胆固醇水平.结果 吸烟组脑梗死患者尿液中8-iso-PGF2α的浓度明显高于对照组(75.79±10.76 vs 67.36±9.18ng/mmol creatinine, P＜0.05).静脉血中LDL总胆固醇、LDL三酰甘油、LDL游离胆固醇在吸烟组与对照组间无显著性差异(分别为5.12±0.61 vs 4.73±0.62mmol/L,0.89±0.07 vs 0.85±0.04mmol/L,1.71±0.43 vs 1.74±0.91mmol/L, P＞0.05).结论 吸烟可以使脑梗死患者尿液中8-iso-PGF2α浓度增高, 增加患者体内的氧化压力.     

心肌梗死延迟增强三维与二维MR成像对比研究

目的 比较屏气三维快速小角度激励序列(3D-FLASH)延迟增强扫描与多次屏气二维快速FLASH(2D-turboFLASH)延迟增强扫描的图像质量及量化梗死面积有无差异.方法 15例心肌梗死患者行单次屏气3D-FLASH及多次屏气2D-反转恢复快速FLASH(IR-turboFLASH)延迟增强检查,以2D序列为标准,比较两者测虽心肌梗死面积比值.同时比较3D图像与2D-原始图、2D-相位敏感重组图的对比噪声比(CNR)并进行视觉评分.采用配对t检验、随机区组设计的方差分析分别对心肌梗死面积及各图像CNR进行分析.结果 3D序列测量心肌梗死面积比值(31.28%)与2D测量结果(30.91%)间差异无统计学意义(t=-0.505,P=0.621),相关性好(r=0.990).2D-相位敏感重组图CNR较其他两者低(3D、2D-原始图及2D-相位敏感重组图CNR分别为43.43±20.67、34.10±14.29和7.59±2.59),且差异具有统计学意义(F=24.376,P<0.01).但视觉评分2D-相位敏感重组图显示正常心肌与梗死心肌对比度最好,而背景噪声最明显(3D组、2D-原始图组及2D-相位敏感图组图像总体质量评分分别为2.33、2.13和2.73,背景噪声分别为2.67、2.53和1.20).结论 屏气3D-FLASH延迟增强扫描量化心肌梗死面积准确性高,图像质量良好,适合临床运用.但受屏气及时间影响大,且需准确选择反转时间.     

急性脑梗死合并代谢综合征对脂蛋白相关磷脂酶A2的影响

目的探讨急性脑梗死合并代谢综合征(metabolic syndrome,MS)对脂蛋白相关磷脂酶A2(lipoprotein-associ-ated phospholipase A2,Lp-PLA2)的影响。方法根据国际糖尿病联盟(IDF)MS诊断标准,将74例急性脑梗死患者分为MS组及非MS组两组。检测各组血浆高密度脂蛋白(HDL)、低密度脂蛋白(LDL)、三酰甘油(TG)及总胆固醇(TC)水平与腰围。结果 MS组LP-PLA2水平(38.87±5.44)较非MS组(36.44±4.15)明显升高,两组比较差异有统计学意义(P=0.037)。同时伴有TG明显升高及腰围的差异。结论 MS患者Lp-PLA2水平升高,Lp-PLA2可能与MS相关。     

飞行员血脂谱调查

目的 调查飞行员血脂水平现状及血脂谱异常特征,并提出血脂异常防治策略及血脂水平划分标准的建议.方法 收集了按我国血脂测定标准化要求测定的591例飞行员、144例其他空勤人员（年龄21～55岁）的血脂谱,1136例普通人群作为对照进行统计分析.每组再按每5岁年龄段分组,分为7个年龄组.分析3组人群不同年龄组血浆三酰甘油（TG）、总胆固醇（TC）、高密度脂蛋白-胆固醇（HDL-C）和低密度脂蛋白-胆固醇（LDL-C）水平及其异常发生率.结果飞行员高TG血症占首位,异常发生率为26.73%.低HDL-C、高TC、高LDL-C异常发生率分别为10.02%、7.28%、6.30%.血脂异常高发生率年龄在36～55岁间,尤其是41～55岁间.血脂异常发生率与飞行员年龄、飞行时间有关,与飞行机种无关.飞行员高TG年龄比普通人群早5岁,HDL-C降低年龄比其TG增高年龄晚10岁,高TC、高LDL-C年龄比普通人群迟5～10岁.飞行员和其他空勤人员高TC发生率,与普通人群相比,差异有显著意义（P＜0.05）.与20年前调查结果相比,飞行员TG水平明显增高、HDL-C水平略有降低,血脂谱已由20年前的高TC血症转变成以高TG、低HDL-C血症为主要特征.本组飞行员与欧洲飞行员相比,血脂异常高发生率年龄段相似,高TG、低HDL-C血症发生率相似,而高TC血症发生率却远远低于欧洲飞行员.结论 飞行员血脂异常防治策略以高TG、低HDL-C为首要目标.提出了我军飞行员血脂水平划分标准和血脂异常防治方案的初步建议.     

CT检测脂肪肝技术与应用进展

脂肪性肝病由一组肝细胞内三酰甘油过度沉积为特征的疾病组成,与肝硬化、肝纤维化及很多代谢性、传染性疾病均有密切关系.CT为常用的脂肪肝影像学检查方法,能够有效地无创性检测肝脏的脂肪沉积.近年来CT设备和技术进展很快,双能量扫描(DECT)等新技术也被用于肝脏脂肪的检测.     

A lineshape fitting model for 1H NMR spectra of human blood plasma.

A lineshape fitting model was constructed for classifying the overlapping information in the 1H NMR spectrum of human blood plasma. A reliable assignment of the overlapping fatty acid (-CH2-)n and -CH3 resonances of the various lipoproteins (VLDL, very low density lipoprotein; LDL, low density lipoprotein; HDL high density lipoprotein) is introduced, and for the first time detailed characteristics (chemical shifts, half linewidths, and relative intensities) of the individual lipoprotein components were obtained directly from the whole plasma spectrum. This was achieved by combining the constructed lineshape fitting model and the proper 400 MHz proton NMR measurements from blood plasma of a healthy donor, from fractions of the different lipoproteins, and from plasma samples in which the lipoprotein fractions were separately added. The results suggest fair promise of future applications of the rapid and easy NMR analysis of lipoprotein distribution in various research and clinical situations.     

Effects of submaximal exercise on high-density lipoprotein-cholesterol subfractions

Acute high-density lipoprotein-cholesterol (HDL) changes were determined in 18 healthy college aged-men completing two-counterbalanced running trials at different exercise intensities: trial 1 at 70 % lactate threshold (LT) (372.5 +/- 28.9 kcal); trial 2 at LT intensity (365.9 +/- 75.9 kcal). For each trial, blood samples were collected at pre-exercise (baseline), 15 min post-exercise (15 m PE) and 24 hours post-exercise (24 h). Serum samples were analyzed for HDL/HDL 2 /HDL 3 subfraction, low density lipoprotein (LDL), very low density lipoprotein (VLDL), total cholesterol (TC), free cholesterol (FC), cholesterol ester, and triglycerides (TG). In addition, capillary blood samples were collected for analysis of blood lactate concentrations during incremental test to determine LT. All samples were corrected for plasma volume changes and compared to pre-exercise (baseline). In assessing the lipid and lipoprotein variables, the significant increase in HDL (p < 0.05) at the 24 h was due to the increase in both HDL 2 and HDL 3. The increase in 15 m PE TC at the LT intensity occurred while the decreases in 24 h TG and VLDL concentrations at the LT intensity occurred at different time periods, respectively. These decreases in the concentrations of TG and VLDL were significantly different, contributing to change in 24 h HDL concentration. No significant difference was determined in changes of HDL over time ratios of FC/CE and HDL 2 /HDL 3. Therefore, the significant increase in 24 h HDL at LT intensity was potentially due to increases in both HDL 2 and HDL 3 subfractions even though 24 h FC was increased significantly. Exercise at LT intensity might favourably alter the lipid profile as demonstrated in 24 h HDL concentration in combination with decreases in TG and VLDL at 24 h post-exercise. Consequently, the LT intensity might appear to be the threshold intensity of acute aerobic exercise (expending 350 kcal) necessary to promote a significant increase in HDL.     

Proton nuclear magnetic resonance lineshape studies on human blood plasma lipids from newborn infants, healthy adults, and adults with tumors.

The usefulness of proton NMR spectroscopy of human blood plasma for cancer research has been extensively studied in recent years. Two main starting points have been offered by Fossel et al. (N. Engl. J. Med. 315, 1369 (1986)) and Mountford et al. (FEBS Lett. 203, 164 (1986)). In this work the experimental proton NMR spectra of blood plasma were analyzed with the aid of the multivariate lineshape fitting method. An appropriate model structure, in terms of the various lipoprotein (VLDL, LDL, and HDL) signals, for the methylene region was used. Neonates, healthy adults, and adults with nonmalignant and malignant tumors were studied. The linewidth of the methylene region was found to be linearly dependent on the relative concentrations of the lipoproteins. The correlation coefficient was -0.89 (P less than 0.001) for VLDL and 0.88 (P less than 0.001) for HDL. A correlation between VLDL concentration and age, 0.76 (P less than 0.001), was also established. VLDL was modeled using two components. The half-linewidth of the lower field component was slightly elevated for the adults with large metastases. This might be in association with the fucose-containing proteolipid complex detected earlier in cancer cells or in sera of cancer patients. Some signals of this complex may fall in the same region of the spectra. The spectra for the neonates were indicated to be totally different from the adults. This and other related questions were explained by means of the model parameters and the relative concentrations of the lipoproteins VLDL, LDL, and HDL. The presented technique can be used as a rapid research tool for figuring out the relative concentrations of the lipoproteins in blood plasma and explaining the reasons behind the changes in the spectra.     

Effect of an 8-week endurance training program on markers of antioxidant capacity in women

AIM: The effects of endurance training and of exhaustive treadmill running on low density lipoprotein (LDL) oxidation in women are not clearly established. METHODS: Twenty training and 10 control persons, all not endurance trained, aged 26+/-4 and 23+/-3 years, were recruited for 8 weeks of running training 3x/week 30 min. The susceptibility of LDL to in vitro oxidation, conjugated dienes, malondialdehyde (MDA), nitric oxide (NO) and cholesterol, lipoproteins, triglycerides, apolipoprotein (apo) A-I, apo B and lipoprotein (a) were determined before and after training, at rest and after exhaustive spiroergometric exercise. The training was tailored individually at the speed of the 4 mmol/L lactate threshold. RESULTS: At rest and after treadmill running, training induced an increase in lag-time (P<0.05), a decrease in MDA (P<0.05), and lower values for cholesterol (P<0.001), LDL (P<0.01), triglycerides (P<0.05) and apo B (P<0.001), but no increase for high density lipoprotein (HDL) or apo A-I. Before training, treadmill running induced lower conjugated dienes and malondialdehyde, after training an increase for LDL and decrease for cholesterol and triglycerides, no increase for HDL or apo A-I. In the control group, all parameters remained unchanged, only NO lowered (P<0.01). CONCLUSION: Endurance training in women shows favorable effects on LDL oxidation, cholesterol, LDL-cholesterol, triglycerides and apo B.     

Plasma lipids, lipoproteins and apolipoproteins and sudden cardiac death

To investigate the risk factors for sudden cardiac death, in particular that triggered by coronary heart disease, we analysed 17 different lipids, lipoproteins and apolipoproteins in the plasma of patients who had suffered sudden death, including sudden cardiac death. Studies were carried out on 107 cadavers comprising 78 subjects where the cause of death was diagnosed as sudden cardiac death and 29 subjects diagnosed with other causes of sudden death. All 107 cases were classified into four groups according to the degree of coronary stenosis and the degree of cardiac hypertrophy. Plasma levels of total cholesterol (T-CHOL), triglyceride (TG), β-lipoprotein (β-LIPO), free fatty acid, phospholipid, free cholesterol, high density lipoprotein cholesterol, lipoprotein(a) [Lp(a)], lipoproteins (VLDL, LDL, HDL) and apolipoproteins (apoAI, apoAII, apoB, apoCII, apoCIII, apoE) were determined. The level of apoB showed a significant difference and positive correlation with the degree of coronary stenosis by two different statistical methods, while the levels of T-CHOL, TG, β-LIPO, VLDL, apoCII, apoCIII and apoE showed significant differences with the degree of coronary stenosis by one statistical method. It was concluded that a high plasma level of apoB is a risk factor for coronary stenosis, with higher levels resulting in more severe degrees of coronary stenosis. Furthermore, a significant difference was found regarding only apoCIII both between the sudden cardiac death group and the sudden death from other causes group, and between each of the four groups classified according to the degree of coronary stenosis. It was thus concluded that a high plasma level of apoCIII indicates the possibility of a coronary stenotic origin for sudden cardiac death. Received: 25 February 1998 / Received in revised form: 24 August 1998     

The physiology of lipoproteins

The seminal studies of Brown and Goldstein (Science 1986;232:34-47) coupled with the findings of the Framingham study revolutionized our understanding of the metabolic basis for vascular disease. These studies led to the widespread use of the coronary risk lipid profile, which uses the total cholesterol/high-density lipoprotein (HDL) ratio (or low-density lipoprotein [LDL]/HDL ratio) in predicting risk for vascular disease and as a tool for therapeutic management of patients at risk for vascular disease. However, although these methods are predictive of coronary artery disease (CAD) in general, it is also well known that the extent of occlusive disease and CAD varies greatly between individuals with similar cholesterol and HDL lipid profiles. For this reason, the National Cholesterol Education Program Expert Panel revised these guidelines and now recommends monitoring LDL and HDL cholesterol in the context of coronary heart disease risk factors and "risk equivalents." In addition, more recent findings indicate that specific alterations in individual lipoprotein subclasses may account for the variations in CAD in subjects with similar lipid profiles. For example, a preponderance of small, dense LDL particles correlates with a marked increase in risk for myocardial infarction independent of LDL levels. In particular, the association of small, dense LDL with elevated triglycerides (large, less dense VLDL) and reduced HDL has been defined as the atherogenic lipoprotein profile, and the key metabolic defect driving this profile may be elevated levels of triglycerides, specifically large, less dense VLDL. In an attempt to explain the physiologic basis for lipoprotein variations, this review describes the basic metabolic scheme underlying the traditional view of lipoprotein metabolism and physiology. It then examines the identity and role of the various lipoprotein subfractions in an attempt to distill a working model of how lipoprotein abnormalities might account for vascular disease in general and the metabolic syndrome in particular.     

The effect of exercise on plasma lipids and LDL subclass metabolism in miniature swine

The effects of exercise on plasma lipids and lipoproteins, high density lipoprotein (HDL) subclass cholesterol levels, and low density lipoprotein (LDL) subclass composition and metabolism were studied in Yucatan miniature swine following 2 yr of training. The exercise protocol produced significant training effects. Post-heparin lipolytic activity was also significantly increased. Although plasma cholesterol and triglycerides did not differ significantly (P = 0.08) between the exercised and control groups, multivariate analysis indicated a strong association between lipoprotein lipase (LPL) and HDL2-C (P less than 0.0001). Although HDL-C levels rose only slightly (P less than 0.09) with exercise, a significant shift was noted in the distribution of cholesterol from the HDL3 to the HDL2 fractions, perhaps mediated by the substantial increase in LPL activity. Exercise had little effect on the chemical composition of the major lipoprotein classes; however, the triglyceride content of the lighter LDL1 subclass was significantly reduced. In the more dense LDL2 subclass, exercise resulted in a significant decrease in triglycerides concomitant with a significant increase in free cholesterol levels. In contrast with the small reductions in fractional catabolic rates (FCR) in either subclass, production rates of the exercised group were reduced, which accounted for the reduction in LDL subclass pool size. These data indicate that exercise produces subtle but significant changes in lipoprotein metabolism that have been previously associated with reduced risk of atherosclerosis.     

不同海拔地区脑梗死患者氧化型低密度脂蛋白、低密度脂蛋白和高密度脂蛋白含量的变化研究

目的：探讨不同海拔地区脑梗死患者血浆氧化型低密度脂蛋白（oxidized low density lipoprotein,ox-LDL）、低密度脂蛋白（low density lipoprotein,LDL）和高密度脂蛋白（high density lipoprotein,HDL）的变化。方法：取不同海拔地区的脑梗死患者84例,其中高海拔地区26例,中海拔地区30例,低海拔地区28例。另选同地区年龄、性别基本匹配,世居当地的健康体检人群为对照组,其中高海拔地区26例,中海拔地区25例,低海拔地区28例。测定不同海拔脑梗死组和对照组血浆ox-LDL、LDL、HDL水平。结果：1随着海拔的逐渐升高,脑梗死组的血浆ox-LDL、LDL含量升高,而血浆HDL含量降低;2高海拔地区健康人群血浆ox-LDL、LDL含量较平原地区升高,血浆HDL含量较平原地区降低。结论：高海拔地区脑梗死患者和健康者的血浆ox-LDL、LDL含量均较中海拔地区和低海拔地区患者升高,而HDL含量较中海拔地区和低海拔地区含量减低。     

Chronic low level physical activity as a determinant of high density lipoprotein cholesterol and subfractions

Physical activity has been associated with reduced risk of coronary heart disease. A mechanism for the reduced risk may be through increased high density lipoprotein cholesterol (HDL-C) and subfractions, in particular HDL2-C. Research associated with increased physical activity investigating HLD-C have assessed the effects of intense aerobic activity. The current research evaluated the relationship between low intensity, long duration activity to HDL-C and subfractions in 35 active postal carriers. Measurements of physical activity via the Large Scale Integrated monitor and reported miles walked, and lipoproteins were assessed at 3-month intervals over a 1-year period. Reported miles walked/day (5.3) was significantly correlated with HLD2-C (r = 0.50, P = 0.003) and approached significance for HDL-C (r = 0.29, P = 0.06). The Large Scale Integrated measures were correlated with HDL-C (r = 0.44, P = 0.008) and HDL2-C (r = 0.44, P = 0.007). Controlling for either age, alcohol consumption, body mass index, or leisure time activity did not reduce the relationship between reported miles walked or Large Scale Integrated readings and HDL2-C, suggesting that the increased HDL-C was the result of long duration, low intensity physical activity.