The Effect of Overuse Activity on Achilles Tendon in an Animal Model: A Biomechanical Study

Musculoskeletal soft tissue injuries from athletic activities are common in the rotator cuff tendons, lateral epicondyle of the elbow, the patella tendon, and the Achilles tendon. Despite the fact that the Achilles tendon is the largest and strongest tendon in the human body, it is frequently injured in the athletic setting. To study the etiology and pathogenesis of Achilles tendon injuries, our goal was to develop a model of Achilles tendon overuse by evaluating the Achilles tendons from animals subjected to the exercise protocol previously described as overuse for the supraspinatus tendon. We hypothesized that the same exercise protocol would produce injuries to the Achilles tendon as demonstrated by changes in the cross-sectional area and biomechanical properties. While a significant injury was induced into the supraspinatus tendon, we found no changes in the Achilles tendons of these exercised animals based on gross observation, geometric measurements, and mechanical testing analyses. Although surprising, there are many possible explanations for these findings including differences in potential injury mechanisms, functional capabilities of the differing tendons, and other factors.     

急性心肌梗死重组链激酶早期溶栓的血液流变性研究

目的 :观察急性心肌梗死重组链激酶早期静脉溶栓前后的血液流变性变化。方法 :对 36例患者分别于溶栓开始前、溶栓治疗后 3h采血进行血液流变学检查。结果 :急性心肌梗死患者溶栓前各项血液流变学指标均明显异常。溶栓 3h后各项血液流变指标明显改善 ,尤以纤维蛋白原、血小板聚集率、凝血酶原时间、红细胞刚性指数为著。结论 :重组链激酶能明显改善急性心肌梗死血液流变学各项异常指标 ,对缩小梗死面积 ,恢复心肌灌注 ,减少并发症 ,防止梗死后心绞痛及再梗死的发生 ,改善预后具有十分重要的作用。     

影响呼吸重症监护病房慢性阻塞性肺病患者机械通气时间的因素

目的:探讨呼吸重症监护病房的慢性阻塞性肺病(COPD)患者机械通气时间分别大于7,14,21 d的潜在危险因素.方法:前瞻性记录和回顾性分析患者在疾病稳定期,入住呼吸重症监护病房时及在呼吸重症监护病房期间的特征.以t检验,X2检验和逻辑回归分析作为统计学方法.结果:63例COPD需要机械通气患者入选.其中26例患者机械...     

The Processing Time for Recanalization and Size of Ischemic Lesions on DWI is Related With Complete Reperfusion After Mechanical Thrombectomy

Recent studies demonstrated that modified thrombolysis in cerebral infarction (TICI) 3 reperfusion have better functional outcomes than modified TICI 2b after mechanical thrombectomy in acute ischemic stroke with large vessel occlusion. The purpose of this study was to determine significant factors to forecast the presence of complete reperfusion after mechanical thrombectomy based on multimodal magnetic resonance imaging (MRI). We investigated 96 consecutive patients with acute large intracranial artery occlusion of anterior circulation who based on multimodal MRI. Also, we compared clinical and radiologic parameters between patients with modified TICI 3 and those with modified TICI 0-2b. Among 96 eligible subjects received mechanical thrombectomy, 39 patients (40.6%) showed complete reperfusion and 57 partial or nonreperfusion (mTICI 2b-26, mTICI 2a-9, mTICI 1-8, and mTICI 0-14) after mechanical thrombectomy. Patients with mTICI 3 had significantly smaller initial Diffusion weighted images (DWI) lesion volume (P < .01) and much shorter time interval from onset to reperfusion (P < .01) than those patients with mTICI (0-2b). In multivariate analysis, smaller initial DWI volume (odds ratio [OR], 1.78; 95% confidence interval [CI], 1.23-2.57; P < .01) and faster reperfusion time (OR, 1.07; 95% CI 1.01-1.14; P = .015) had an independence significance for complete reperfusion after mechanical thrombectomy. In this study, the ischemic lesion volume on DWI and faster processing time are critical factor to predict the state of complete reperfusion after mechanical thrombectomy.     

应用机械通气救治急性药物中毒并急性呼吸衰竭

目的观察早期应用机械通气对急性药物中毒患者并发急性呼吸功能不全和急性呼吸功能衰竭的影响。方法对40例急性药物中毒患者均在确诊为急性呼吸功能不全和衰竭后立即给予机械通气,并动态监测机械通气前和机械通气后30min、1h、12h、24h、48h、72h和脱机前动脉血气。通过统计学分析比较不同时期的动脉血气分析结果。结果所有患者在机械通气12h后,低氧血症均有不同程度的改善,34例患者在机械通气后48h低氧血症均明显改善,36例患者72h后动脉血气均恢复正常。与上机前相比均有非常显著性差异(P<0.01)。结论急性药物中毒并发呼吸衰竭患者,对于病因的治疗虽至关重要,但呼吸功能的支持和监测是预后的关键。因此,适当放宽机械通气指征,尽早给予机械通气,有利于防治因急性呼吸功能不全引发的多脏器功能障碍综合征,提高急性药物中毒救治成功率,降低其死亡率。     

机械通气治疗腹部外伤术后成人呼吸窘迫综合征

目的探讨机械通气对腹部外伤术后成人呼吸窘迫综合征(ARDS)的治疗作用。方法对24例本病患者采用A/C、SIMV、PEEP、正比呼吸模式及综合治疗。结果抢救成功14例,死亡10例,分别死于心、肾、脑等脏器功能衰竭。结论早期和及时有效的机械通气是救治腹部外伤术后ARDS的重要手段。     

Multi-level characterization of human femoral cortices and their underlying osteocyte network reveal trends in quality of young,aged, osteoporotic and antiresorptive-treated bone

Characterization of bone's hierarchical structure in aging, disease and treatment conditions is imperative to understand the architectural and compositional modifications to the material and its mechanical integrity. Here, cortical bone sections from 30 female proximal femurs – a frequent fracture site – were rigorously assessed to characterize the osteocyte lacunar network, osteon density and patterns of bone matrix mineralization by backscatter-electron imaging and Fourier-transform infrared spectroscopy in relation to mechanical properties obtained by reference-point indentation. We show that young, healthy bone revealed the highest resistance to mechanical loading (indentation) along with higher mineralization and preserved osteocyte-lacunar characteristics. In contrast, aging and osteoporosis significantly alter bone material properties, where impairment of the osteocyte-lacunar network was evident through accumulation of hypermineralized osteocyte lacunae with aging and even more in osteoporosis, highlighting increased osteocyte apoptosis and reduced mechanical competence. But antiresorptive treatment led to fewer mineralized lacunae and fewer but larger osteons signifying rejuvenated bone. In summary, multiple structural and compositional changes to the bone material were identified leading to decay or maintenance of bone quality in disease, health and treatment conditions. Clearly, antiresorptive treatment reflected favorable effects on the multifunctional osteocytic cells that are a prerequisite for bone's structural, metabolic and mechanosensory integrity.     

种植体结构改变对种植体-骨界面皮质骨区应力影响的三维有限元分析

背景：种植体-骨界面的生物力学效应是骨吸收重要的影响因素之一。模仿天然牙周膜的新结构种植体或可改善其界面应力的分布情况。 目的：探讨不同的咬合负载条件下,改变传统种植体内部结构对种植体-骨界面皮质骨区应力分布、峰值的影响,为新结构种植体的优化设计及临床应用提供理论依据。 方法：用Pro/ENGINEER软件建立新结构的种植体(模型A)与无螺纹的传统柱状种植体(模型B)的数字模型,采用Ansys软件分析在相同骨质及相同受力环境下种植体-骨界面皮质骨区应力峰值、应力带分布的变化规律。 结果与结论：垂直加载时,模型A在不同受力大小时应力峰值均较模型B降低17.54%;45°加载时,模型A应力峰值较模型B降低(2.59%),模型B的高应力区向颊侧集中趋势明显。咀嚼模拟加载时,模型A的应力峰值均较模型B低,其差值在施力方向与种植体轴向夹角(β)等于12°时最大(0.353 2 MPa),在β > 12°后逐渐减小;并且模型A在促进骨组织生长最适应力峰值、维持骨组织健康应力峰值两个量化指标中,均比模型B适用角度范围大(A：0°-28°,0°-58°;B：0°-24°,0°-56°)。提示优化设计种植体结构的改变可改善种植体-骨界面皮质骨区的应力分布,降低应力峰值,可在更大范围内降低骨皮质吸收的风险。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

脊柱颈胸结合部C5~T2三维有限元建模与验证

目的基于CT图像数据建立人体脊柱颈胸结合部C5~T2的三维有限元模型,并验证模型的正确性和有效性。方法采用Mimics、Geomagic和Hypermesh软件对人体脊柱颈胸结合部C5~T2椎体进行三维重建、模型修复和有限元前处理,对模型顶面施加±0.5、1、1.5、2 N·m扭矩,用于模拟人体前屈和后伸活动时所产生的载荷作用,使用ANSYS软件计算脊柱颈胸结合部C5~T2节段在前屈和后伸承受扭矩载荷作用时的关节活动度(range of motion,ROM),将计算结果与前人研究结果进行对比分析。结果人体脊柱颈胸结合部C5~T2三维模型中C5~6、C6~7、C7~T1和T1~2各节段椎体在1 N·m载荷作用下,前屈时ROM分别为4.30°、3.21°、1.66°和1.41°,后伸时ROM分别为3.47°、2.86°、0.96°和0.92°。前屈时最大应力出现在椎体前缘,后伸时椎体后缘出现较大应力。ROM和应力分布的趋势与前人研究结果相一致。结论建立的脊柱颈胸结合部三维模型精确逼真,符合脊柱颈胸结合部的生物力学特性,模拟结果可为临床病理研究和颈胸部手术术式的评价提供理论依据。     

3D生物描绘孔结构可控钙磷硅基骨修复支架的生物力学性能

目的设计和制备新型钙磷硅基骨修复支架,研究其在不同外力作用下体外生物力学性能。方法以自固化磷酸钙骨水泥(calcium phosphate cement,CPC)、介孔硅酸钙(mesporous calcium silicate,MCS)为原料,通过3D生物描绘技术构建孔径分别为350、500μm的MCS/CPC复合支架。采用扫描电镜观察支架表面形貌;分别通过万能力学试验机和动态力学分析仪,考察具有不同孔道结构MCS/CPC支架的抗压力学性能和不同频率动态周期性载荷作用下的力学性能。结果通过3D生物描绘技术能够实现对钙磷硅基骨修复支架内部孔道结构的可控制备。孔径为350μm的MCS/CPC支架具有较高的抗压力学强度[(9.80±0.39)MPa]和抗压模量[(132.50±4.30)MPa];此外,载荷频率在1~100 Hz范围内,孔径为350μm的支架具有较高的储能模量。结论通过3D生物描绘技术制备的孔径为350μm的MCS/CPC复合支架不仅具有规则的连通孔道,还具有较高的抗压力学性能,能在动态载荷作用下保持结构稳定,适合作为一种新型的骨缺损修复材料。