强化调脂治疗对急性心肌梗死患者大动脉弹性的影响

目的探讨强化调脂治疗对急性心肌梗死患者大动脉弹性的影响。方法急性心肌梗死患者52例,依据血清低密度脂蛋白胆固醇(LDL-C)水平分为胆固醇正常组(n=17)和胆固醇升高组(n=35),观察辛伐他汀(舒降之)强化调脂(40mg/d)治疗6月后脉搏波传导速度(PWV)和踝肱指数(ABI)的改变。结果强化调脂治疗6月后,胆固醇正常组和胆固醇升高组患者的血清LDL-C水平均显著降低[(2.1±0.3)vs(1.6±0.3),(3.4±0.8)vs(2.3±0.5)mmol/L,P<0.01],胆固醇正常组及胆固醇升高组各动脉段的PWV均显著降低,P均<0.05。胆固醇升高组各动脉段的PWV也显著降低,P均<0.05。各动脉段之间PWV的降低程度相似。胆固醇升高组的PWV降低比胆固醇正常组更明显。调脂治疗后胆固醇正常组ABI显著升高[(1.1±0.2)vs(1.2±0.1),P<0.05],胆固醇升高组ABI也显著升高[(1.0±0.2)vs(1.2±0.2),P<0.01],其改善程度显著大于胆固醇正常组[(0.2±0.2)vs(0.1±0.1),P=0.02]。结论对急性心肌梗死患者给予积极的强化调脂治疗可显著改善其大动脉弹性,逆转大动脉粥样硬化进展,胆固醇升高的患者获益更大。     

Elastic properties of stored red blood cells from sickle trait donor units

BACKGROUND AND OBJECTIVES: Red blood cells (RBCs) from patients with sickle cell disease present reduced deformability. The aim of this study was to analyse the elasticity of stored RBCs from patients with the sickle cell trait (AS). MATERIALS AND METHODS: The cell elasticity was studied, using laser optical tweezers, on storage days 1, 14, 21, 28 and 35. RESULTS: The elasticity of RBC from AS units stored for 1, 14 and 21 days was significantly greater compared with that of control RBC cells stored for the same time-period. More than 30% of the cells from AS units stored for 28 or 35 days were very rigid and escaped from the optical trap. CONCLUSIONS: RBCs became rigid during storage, suggesting that haemoglobin S might compromise the cell elasticity.     

Stress release drives symmetry breaking for actin-based movement

By using a simple assay composed of purified proteins, we studied the spontaneous polarization of actin networks polymerizing on spherical beads, which subsequently undergo movement. We show evidence that this symmetry breaking is based on the release of elastic energy, analogous to the fracture of polymer gels. The dynamics of this process and the thickness at which it occurs depend on the growth rate and mechanical properties of the actin gel. We explain our experimental results with a model based on elasticity theory and fracture mechanics.     

新发高血压病人游离脂肪酸与动脉弹性变化

目的观察一个人群中新发高血压病人和未发生高血压者基线空腹血清游离脂肪酸(FFA)与2年内动脉弹性的变化的相关性,探索血清FFA、动脉弹性及高血压之间的关系。方法一纵向研究。社区筛选128例健康非高血压者(年龄33～60岁),随访2年。记录新发高血压例数,采用CVProfilorDO-2020型动脉弹性功能测定仪检测两组2年前后大、小动脉弹性指数(C1和C2),测定基线空腹血FFA、血脂、血糖、胰岛素等。随访期间,有12人失访。结果1)与未发生高血压者(n=97)相比,新发高血压病人(n=19)基线空腹血清饱和脂肪酸水平增高[(217±68)μmol/L比未发生高血压组:(186±46)μmol/L,P=0.04],而多不饱和与饱和脂肪酸比值(P/S)降低(1.60±0.37比未发生高血压组:1.90±0.46,P=0.009);2)与未发生高血压者相比,新发高血压者2年的收缩压和舒张压水平增高(P均<0.01),而其大、小动脉弹性指数改变值(ΔC1和ΔC2)有降低趋势(P均>0.05);3)逐步线性回归模型分析显示:全部参与者2年的ΔC1与基线空腹血清P/S正相关(标准回归系数0.201,P=0.041),独立于基线收缩压水平和经典的心血管危险因素。4)Logistic回归模型分析显示新发高血压者的基线空腹血清P/S的优势比(OR值)和95%可信区间为0.412(0.172～0.991,P=0.048)(在调整了经典的高血压危险因素后)。结论空腹血FFA组成异常是中青年非高血压人群大动脉弹性年龄相关改变和发生高血压的危险因素之一。     

短期补充鱼油对超重高血压患者大动脉弹性的改善作用

目的:探讨超重的原发性高血压(高血压)患者短期摄入富含n-3脂肪酸的鱼油对其动脉弹性的影响。方法:社区高血压患者52例(男41例,女11例)经洗脱期去除6例后,随机分为鱼油组(n=23,补充3 g／d鱼油胶囊)和安慰剂组(n=20,试验过程中有3例被去除,补充3粒/d安慰剂)共8周。桡动脉脉搏波测定法测量大、小动脉弹性指数(C1和C2),测定空腹血清游离脂肪酸组成、血脂、血糖、胰岛素等。结果:鱼油对高血压患者空腹血清游离脂肪酸组成的影响:鱼油组干预前后即基线与8周后比较,n-3多不饱和脂肪酸水平、多不饱和脂肪酸／饱和脂肪酸比值均显著性增加。RM-ANOVA分析显示两组之间n-3多不饱和脂肪酸水平、多不饱和脂肪酸／饱和脂肪酸比值在基线与8周后的变化趋势存在显著性差异(P=0．027和P=0．008),协方差分析显示两组之间它们的变化趋势存在显著性差异(P=0．013和P=0．007)。鱼油对高血压患者动脉弹性指数、心率和血压水平的影响:安慰剂组大动脉弹性指数在基线和8周后之间保持不变,而鱼油组大动脉弹性指数则显著性增高,RM- ANOVA分析显示两组大动脉弹性指数的变化趋势有显著性差异(P=0．027)。多元线性回归分析显示,在调整了年龄、性别、体重指数改变、收缩压改变、舒张压改变和心率改变之后,全部参与者基线与8周后大动脉弹性指数的改变、空腹血清游离多不饱和脂肪酸／饱和脂肪酸比值的改变呈独立正相关(标准回归系数为0．415,P=0．004)。结论:超重高血压患者短期鱼油补充改善其大动脉弹性,与其改变的空腹血清游离脂肪酸组成独立相关。     

声触诊弹性成像技术量化评估孕晚期妊娠糖尿病患者胎盘弹性

目的 评价声触诊弹性成像(STE)技术量化评估孕晚期妊娠糖尿病(GDM)患者胎盘弹性的价值。方法 前瞻性纳入51例确诊的孕晚期GDM患者,由2名医师分别以STE技术测量胎盘母体面及胎儿面弹性模量,其中1名医师测量2次;以组内相关系数(ICC)及Bland-Altman图评价观察者内及观察者间测量结果的一致性,比较胎盘母体面及胎儿面平均弹性模量(E_mean)差异。结果 观察者内及观察者间测量GDM患者胎盘母体面及胎儿面弹性模量的一致性均好(观察者内:ICC=0.908、0.887;观察者间:ICC=0.827~0.905)。Bland-Altman图示STE量化评估胎盘弹性的一致性良好。胎盘母体面及胎儿面的中位E_mean分别为6.01(5.62,6.51) kPa及5.02(4.46,5.52) kPa,差异有统计学意义(P＜0.001)。结论 STE可稳定地量化评估孕晚期GDM患者胎盘弹性;胎盘母体面及胎儿面弹性存在差异。     

Anisotropic growth shapes intestinal tissues during embryogenesis

Embryogenesis offers a real laboratory for pattern formation, buckling, and postbuckling induced by growth of soft tissues. Each part of our body is structured in multiple adjacent layers: the skin, the brain, and the interior of organs. Each layer has a complex biological composition presenting different elasticity. Generated during fetal life, these layers will experience growth and remodeling in the early postfertilization stages. Here, we focus on a herringbone pattern occurring in fetal intestinal tissues. Common to many mammalians, this instability is a precursor of the villi, finger-like projections into the lumen. For avians (chicks’ and turkeys’ embryos), it has been shown that, a few days after fertilization, the mucosal epithelium of the duodenum is smooth, and then folds emerge, which present 2 d later a pronounced zigzag instability. Many debates and biological studies are devoted to this specific morphology, which regulates the cell renewal in the intestine. After reviewing experimental results about duodenum morphogenesis, we show that a model based on simplified hypothesis for the growth of the mesenchyme can explain buckling and postbuckling instabilities. Being completely analytical, it is based on biaxial compressive stresses due to differential growth between layers and it predicts quantitatively the morphological changes. The growth anisotropy increasing with time, the competition between folds and zigzags, is proved to occur as a secondary instability. The model is compared with available experimental data on chick’s duodenum and can be applied to other intestinal tissues, the zigzag being a common and spectacular microstructural pattern of intestine embryogenesis.     

FibroScan临床应用新进展

近10年来,应用瞬时弹性扫描仪(FibroScan)作为肝纤维化的无创检测方法已得到广泛共识.为了更有效地利用该技术,设备制造者在原有基础上进行了软件升级及硬件扩展.虽然观察时间尚短,但已有文献表明改进后的技术可能适用范围更广.除肝纤维化检测外,研究还发现FibroScan检测结果与患者的疾病进展和生存情况相关.作为一项技术手段,诸多因素会影响其操作成功率和检查准确率,了解这些因素有利于降低检测失败率,提高检测效能.