阿托伐他汀辅助治疗老年单纯收缩期高血压的疗效观察及对动脉弹性的影响

目的探讨阿托伐他汀在老年单纯性收缩期高血压治疗中的临床疗效及对动脉弹性的影响。方法将我院收治的177例老年单纯收缩期高血压患者按照分层随机分组法分为四组,A1组和A2组为联合用药组,两组均给予阿托伐他汀+氨氯地平,B1组和B2组为单独用药组,两组均给予氨氯地平,A1和B1组年龄在60~75岁,A2和B2组年龄在75岁以上,观察四组患者的临床疗效及动脉弹性指数。结果联合用药组SBP达标率、脉压差(PP)、动脉弹性指数及血管内皮功能改善情况显著优于单独用药组,两组间差异有统计学意义(P<0.05);A1组SBP达标率、PP、动脉弹性指数及血管内皮功能改善情况显著优于A2组,B1组以上观察指标也显著优于B2组,不同年龄患者组间差异有统计学意义(P<0.05)。结论阿托伐他汀能显著提高临床疗效和改善动脉弹性,不同年龄段患者临床获益率不同,年龄越小获益率越大。     

Measurement of Liver Stiffness Using Shear Wave Elastography in a Rat Model: Factors Impacting Stiffness Measurement with Multiple- and Single-Tracking-Location Techniques

The clinical use of elastography for monitoring fibrosis progression is challenged by the subtle changes in liver stiffness associated with early-stage fibrosis and the comparatively large variance in stiffness estimates provided by elastography. Single-tracking-location (STL) shear wave elasticity imaging (SWEI) is an ultrasound elastography technique previously found to provide improved estimate precision compared with multiple-tracking-location (MTL) SWEI. Because of the improved precision, it is reasonable to expect that STL-SWEI would provide improved ability to differentiate liver fibrosis stage compared with MTL-SWEI. However, this expectation has not been previously challenged rigorously. In this work, the performance of STL- and MTL-SWEI in the setting of a rat model of liver fibrosis is characterized, and the advantages of STL-SWEI in staging fibrosis are explored. The purpose of this study was to determine what advantages, if any, arise from using STL-SWEI instead of MTL-SWEI in the characterization of fibrotic liver. Thus, the ability of STL-SWEI to differentiate livers at various METAVIR fibrosis scores, for ex vivo postmortem measurements, is explored. In addition, we examined the effect of the common confounding factor of fluid versus solid boundary conditions in SWEI experiments. Sprague-Dawley rats were treated with carbon tetrachloride over several weeks to produce liver disease of varying severity. STL and MTL stiffness measurements were performed ex vivo and compared with the METAVIR scores from histological analysis and the duration of treatment. A strong association was observed between liver stiffness and weeks of treatment with the liver toxin carbon tetrachloride. Direct comparison of STL- and MTL-SWEI measurements revealed no significant difference in ability to differentiate fibrosis stages based on SWEI mean values. However, image interquartile range was greatly improved in the case of STL-SWEI, compared with MTL-SWEI, at small beam spacing.     

Effect of hormone therapy on carotid elasticity in postmenopausalwomen by Echo-tracking technique

background Studies showed that arterial elasticity changes appear earlier than any structural changes, therefore, its accurate evaluation could be applied at early stage to prevent disease. Echo-tracking(E-tracking) technique can track the wall motion trajectory in real-time, calculate the change in vascular diameter automatically, and assessment of vascular stiffness and flexibility directly. This article aims to assess the change of elasticity of carotid artery after hormone therapy (HT) using Echo-tracki...     

Stresses and Displacements in Functionally Graded Materials of Semi-Infinite Extent Induced by Rectangular Loadings

This paper presents the stress and displacement fields in a functionally graded material (FGM) caused by a load. The FGM is a graded material of Si₃N₄-based ceramics and is assumed to be of semi-infinite extent. The load is a distributed loading over a rectangular area that is parallel to the external surface of the FGM and either on its external surface or within its interior space. The point-load analytical solutions or so-called Yue’s solutions are used for the numerical integration over the distributed loaded area. The loaded area is discretized into 200 small equal-sized rectangular elements. The numerical integration is carried out with the regular Gaussian quadrature. Weak and strong singular integrations encountered when the field points are located on the loaded plane, are resolved with the classical methods in boundary element analysis. The numerical integration results have high accuracy.     

实时超声测量用于等长收缩条件下修复跟腱应变的研究

跟腱（Achilles tendon,AT）在人体运动中承受了巨大的应力,它的力学特性,尤其是撕裂后的力学特性,引起了大量的研究兴趣。在康复治疗中,运动的类型和强度是防止修复的肌腱受到再损伤的关键。治疗师通常根据肿胀、炎症反应等临床症状来定性评估病人的康复训练适当与否。本研究采用了7.5MHz的线阵型超声探头,对等长收缩下修复跟腱的应变进行了测量。实验中6名进行了跟腱修复手术的男性受试者的年龄介于28~51岁之间,撕裂距离跟腱附着点2-7cm。手术后12.8±1.3个星期进行测量,以受试者的健康脚为对照组。研究还对三位健康男性受试者惯用脚和非惯用脚跟腱弹性特征的差异进行了测试。超声图像取自沿肌腱方向的撕裂处,采用Cybex 6000同时在体采集等长收缩条件下跟腱的超声图像以及腓肠肌-比目鱼肌产生的扭矩。定制的踝足矫形器可用于超声成像平面与肌腱位置的校准,以便由超声图像提取肌腱特定部位的应变信息。实验利用成像技术对离体猪肌腱的测量,证明了超声测量的有效性。我们发现跟腱撕裂修复位置的应变较对侧健康腿小14.8%±12.6%,两者存在显著差异（p=0.017）。今后可进一步研究沿肌腱方向上应变的分布以及康复过程中分布的变化。本研究将有助于跟腱修复手术后病人训练计划的制定和优化。     

Mechanical properties of the Schneiderian membrane in vitro

Objectives: Perforation of the Schneiderian membrane (maxillary sinus mucosa) is a common complication of maxillary sinus graft procedures. Membrane perforation increases the chance of postoperative sinusitis and endangers graft as well as implant survival. The aim of the present study was to explore the mechanical properties of the Schneiderian membrane.
Material and methods: Three test methods were performed on sinus specimen of 20 fresh human cadavers: one- and two-dimensional membrane elongation as far as perforation, as well as membrane detachment from the adherent bone.
Results: Perforation of the Schneiderian membrane (mean thickness: 90 μm) occurred at a mean tension of 7.3 N/mm². The membrane could be stretched to 132.6% of its original size in one-dimensional elongation, and to 124.7% in two-dimensional elongation. Thicker membranes demonstrated significantly higher load limits ( P <0.001). The mean modulus of elasticity accounted 0.058 GPa, the mean adhesion force between sinus membrane and bone surface was 0.05 N/mm.
Conclusions: Respecting the mechanical properties of the Schneiderian membrane may help reducing the complication rates and thus patient morbidity in minimally invasive maxillary sinus floor elevation.     

Increased subcutaneous adipose tissue impairs dermal function in diet‐induced obese mice

Please cite this paper as: Increased subcutaneous adipose tissue impairs dermal function in diet‐induced obese mice. Experimental Dermatology 2010; 19 : 878–882. Abstract: Increment of subcutaneous adipose tissue is a risk factor for facial morphological changes, such as sagging, which may be at least partly because of the increased weight burden of accumulated fat. However, it is not clear how the increase of subcutaneous adipose tissue affects dermal structure and function. We examined this issue in HR‐1 hairless mice given a high‐fat diet (HFD). After having been fed with HFD for 12 weeks, the mice became obese and the subcutaneous adipose tissue layer was significantly thickened, while the dermal layer became significantly thinner than that of control mice fed normal diet. However, the thickness of the dermal layer was not changed in the ear pinna, which lacks a subcutaneous adipose layer, suggesting that increase of subcutaneous adipose tissue may induce dermal changes. The number of dermal fibroblasts in the dermis was significantly reduced in obese mice, although there was no change in gene expression levels of extracellular matrix components, including collagen, hyaluronic acid synthase, fibulin5, fibrillin‐1, laminin β1, matrix metalloproteinases and tissue inhibitor of metalloproteinases. Dermal elasticity was significantly decreased in obese hairless mice. These results suggest that subcutaneous adipose cells in obese mice may reduce the proliferation of dermal fibroblasts and induce a decrease of dermal thickness and elasticity. Therefore, the increment of the subcutaneous adipose layer in obese subjects may induce impairment of dermal biomechanical characteristics and promote the appearance of sagging.     

Comparative study of skin sebum and elasticity level in patients with sulfur mustard‐induced dermatitis and healthy controls

Background: Sulfur mustard (SM) – a chemical agent – has both acute and chronic effects on skin. Xerosis, which is deemed to be due to the damage of hydrolipidic barrier of the skin, is the most common complaint of veterans exposed to the chemical. This study was designed to evaluate skin sebum and elasticity in veterans with a history of SM contact. Methods: Three hundred and ten subjects were enrolled in this study and were divided into four groups: SM‐exposed patients with current skin lesions (n=87); SM‐exposed patients without skin lesions (n=71); patients with dermatitis (n=78); and normal controls (n=74). The skin sebum and elasticity were measured in four areas (forehead, suprasternal, palm and back of the hands) using a Sebumeter and a Reviscometer. Results: Skin sebum was higher in participants who presented with dermatitis and had history of contact with SM than others; the difference was only statistically significant on the forehead. There was no significant difference in the skin elasticity between the four groups. Conclusion: While SM may increase skin sebum in long term, there is no evidence that it has a substantial effect on skin elasticity.