流体剪切力对MC3T3-E1细胞OPG、RANKL蛋白表达的实验研究

目的探讨流体剪切力(fluid shear stress,FSS)作用下,两种调节骨骼重建的重要分子骨保护素(osteoprotegerin,OPG)和细胞核因子κB受体活化因子配体(receptor activator of NF-κB ligand,RANKL)的蛋白表达情况。方法采用体外模型对MC3T3-E1细胞加载流体剪切力,细胞经不同时间加力后(0,30,60,90,120min),对细胞分别进行染色和裂解,运用免疫荧光和蛋白印迹法对OPG和RANKL的蛋白表达水平进行定量分析。结果 FSS作用30,60,90,120min后能够显著增加OPG的蛋白表达(P0.05),减少RANKL的蛋白表达(P0.05)。两者共同作用使得OPG/RANKL值显著增高(P0.05)。结论流体剪切力刺激提示OPG/RANKL的比值可能在成骨细胞和破骨细胞联合调节骨骼形成和吸收的过程中起着重要的调节作用。     

Shear-dependent platelet aggregation size

Nonsurgical bleeding is the most frequent complication of left ventricular assist device (LVAD) support. Supraphysiologic shear rates generated in LVAD causes impaired platelet aggregation, which increases the risk of bleeding. The effect of shear rate on the formation size of platelet aggregates has never been reported experimentally, although platelet aggregation size can be considered to be directly relevant to bleeding complications. Therefore, this study investigated the impact of shear rate and exposure time on the formation size of platelet aggregates, which is vital in predicting bleeding in patients with an LVAD. Human platelet-poor plasma (containing von Willebrand factor, vWF) and fluorochrome-labeled platelets were subjected to a range of shear rates (0-10 000 s⁻¹) for 0, 5, 10, and 15 minutes using a custom-built blood-shearing device. Formed sizes of platelet aggregates under a range of shear-controlled environment were visualized and measured using microscopy. The loss of high molecular weight (HMW) vWF multimers was quantified using gel electrophoresis and immunoblotting. An inhibition study was also performed to investigate the reduction in platelet aggregation size and HMW vWF multimers caused by either mechanical shear or enzymatic (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13—ADAMTS13, the von Willebrand factor protease) mechanism under low and high shear conditions (360 and 10 000 s⁻¹). We found that the average size of platelet aggregates formed under physiological shear rates of 360-3000 s⁻¹ (200-300 μm²) was significantly larger compared to those sheared at >6000 s⁻¹ (50-100 μm²). Furthermore, HMW vWF multimers were reduced with increased shear rates. The inhibition study revealed that the reduction in platelet aggregation size and HWM vWF multimers were mainly associated with ADAMTS13. In conclusion, the threshold of shear rate must not exceed >6000 s⁻¹ in order to maintain the optimal size of platelet aggregates to “plug off” the injury site and stop bleeding.     

剪切波弹性成像与FNA-Tg对甲状腺乳头状癌侧颈部淋巴结转移的诊断价值

目的：探讨剪切波弹性成像(shear wave elastography,SWE)与细针穿刺洗脱液甲状腺球蛋白(fine-needle aspiration washout thyroglobulin,FNA-Tg)对甲状腺乳头状癌侧颈部淋巴结转移的诊断价值。方法：回顾性分析159例经病理证实为甲状腺乳头状癌(papillary thyroid carcinoma,PTC)的患者资料,对颈部211枚可疑淋巴结进行常规超声、SWE参数平均值(E_mean)、FNA-Tg检查,以术后病理结果为金标准,比较各检测方法的诊断效能。结果：(1)SWE E_mean转移组[(50.96±27.66) kPa]高于非转移组[(32.20±17.34) kPa],差异有统计学意义(t=8.761,P<0.01)。受试者工作特征(receiver operating characteristic,ROC)曲线分析表明,SWE E_mean最佳诊断阈值为40.42 kPa时对PTC颈部淋巴结转移预测价值较高,曲线下面积(area under...     

Comparison of 2 shear wave elastography systems in reproducibility and accuracy using an elasticity phantom

This study aimed to compare the accuracy and inter- and intra-observer reproducibility of the measured elasticity between 2 shear wave elastography systems. Three breast radiologists examined 8 targets of 4 different levels of stiffness (size: 11 mm, 4 mm) in an elasticity phantom (Customized 049A Elasticity QA Phantom, CIRS, Norfolk, VA, USA) using 2 different shear wave ultrasound elastography systems: SuperSonic Imagine (SSI) (SSI, Aix en Provence, France) and ShearScan (RS-80A, Samsung Medison, Seoul, Korea). Three radiologists performed ultrasound (US) elastography examinations for the phantom lesions using 2 equipment over a 1-week interval. Intra- and inter-observer reproducibility and the accuracy of the measured elasticity were analyzed and compared between the 2 systems. The accuracy of shape was also analyzed by shape-matching between B-mode and elastography color image. Intra-class correlation coefficients (ICC) were used in statistical analysis. For measured elasticity, the intra-observer and inter-observer reproducibility were excellent in both SSI and ShearScan (0.994 and 0.998). The overall accuracy was excellent in both systems, but the accuracy in small lesions (4 mm target) was lower in SSI than ShearScan (0.780 vs 0.967). The accuracy of shape-matching on the elastography image was 59.0% and 81.4% in the SSI and ShearScan, respectively. In conclusion, the SSI and ShearScan showed excellent intra- and inter-observer reproducibility. The accuracy of the Young''s modulus was high in both the SSI and ShearScan, but the SSI showed decreased accuracy in measurement of elasticity in small targets and poor shape-matching between the B-mode image and color-coded elastography image.     

Rheological studies on the solubilization by the surfactant SDS of complexes between three acidic polysaccharides and an organic base chloride

Developments in the solubilization of complexes between the cationic polymer, poly(hexamethylenebiguanidinium chloride) (PHMBH⁺Cl^-) and acidic polysaccharides are reported. It was discovered that the anionic detergent sodium dodecyl sulphate (SDS) is an excellent solubilizer for these complexes, enabling several multi-component systems to be studied. SDS itself was shown to interact with PHMBH⁺CL^- to form a highly viscous solution. Maximum viscosity was obtained with a SDS : PHMBH⁺CL^- molar ratio of 15.6. SDS : PHMBH⁺Cl^- at this ratio served as a good solubilizer for the acidic polysaccharides (sodium alginate, sodium carboxymethyl cellulose, and xanthan), forming highly viscous fluids. The effect of temperature on the viscosity of these solutions was also examined.     

The Immediate Effects of Foam Rolling and Stretching on Iliotibial Band Stiffness: A Randomized Controlled Trial

BackgroundIliotibial Band Syndrome (ITBS) is a common clinical condition likely caused by abnormal compressive forces to the iliotibial band (ITB). Stretching interventions are common in ITBS treatment and may predominantly affect tensor fascia latae (TFL). Another ITBS treatment is foam rolling, which may more directly affect the ITB. Shear wave ultrasound elastography (SWUE) measures real-time soft tissue stiffness, allowing tissue changes to be measured and compared.PurposeTo examine effects of foam rolling and iliotibial complex stretching on ITB stiffness at 0˚ and 10˚ of hip adduction and hip adduction passive range of motion (PROM).Study DesignRandomized controlled trial.MethodsData from 11 males (age = 30.5 ± 9.0 years, Body Mass Index (BMI) = 27.8 ± 4.0) and 19 females (age = 23.5 ± 4.9, BMI = 23.2 ± 2.1) were analyzed for this study. Subjects were randomly assigned to one of three groups: control, stretching, and foam rolling. Shear wave ultrasound elastography measurements included ITB Young’s modulus at the mid-thigh, the distal femur and the TFL muscle belly. ITB-to-femur depth was measured at mid-thigh level. Hip adduction PROM was measured from digital images taken during the movement.ResultsNo significant interactions or main effects were found for group or time differences in ITB Young’s modulus at the three measured locations. The ITB stiffness at the mid-thigh and distal femur increased with 10° adduction, but TFL stiffness did not increase. A main effect for adduction PROM was observed, where PROM increased 0.8˚ post-treatment (p = 0.02).ConclusionA single episode of stretching and foam rolling does not affect short-term ITB stiffness. The lack of ITB stiffness changes may be from an inadequate intervention stimulus or indicate that the interventions have no impact on ITB stiffness.Levels of Evidence1b