基于纤维增强超弹性基体模型的骨骼肌有限元模拟

为了进一步研究骨骼肌复杂的机械动力行为,采用有限元方法对骨骼肌行为进行力学分析.将骨骼肌视为肌纤维和超弹性基体构成的复合材料,纤维应力分为主动和被动两部分,主动应力依赖于疲劳状态、激励波形、收缩速度和现时长度,而被动应力与普通材料相同,仅依赖于现时应变.利用商用软件ABAQUS,对蛙大腿肌进行数值模拟,比较在周期激励作用下,不同时刻的单轴应变和代表性节点的位移分布规律.结果显示,骨骼肌表现出大变形特性,单轴最大应变达到69%.而且由于引入了疲劳函数,所采用的数值分析技术可模拟骨骼肌的主动与被动机械行为,且容易实现,结果稳定可靠.     

Glucose Uptake at Rest and During Contraction in Isolated Dog Skeletal Muscle1

Costin , J. C., B. Saltin , N. S. Skinner , Jr . and G. Vastagh , Glucose uptake at rest and during contraction in isolated dog skeletal muscle. Acta physiol. scand. 1971. 81. 124–137. In an in situ isolated canine gracilis muscle preparation the a-v difference for glucose, oxygen, and lactate has been studied at rest and during stimulation. Both free flow (systemic blood flow) and constant flow perfusion (blood from reservoir) have been applied and in both sets of experiments the blood flow has been determined. In the constant flow experiments no significant difference in the glucose uptake could be detected between stimulation as compared with rest. In the free flow experiments the same stimulation frequency produced a significant uptake of glucose (? 20 μg glucose per g muscle and minute), which could account for approximately 10 per cent of the total energy output and 20–30 per cent of the total carbohydrate utilization. It is suggested that the difference between the free flow and the constant flow experiments was due to the fact that, in the free flow experiments where the muscle is perfused with the systemic blood flow, some humoral factor is present which is necessary for the glucose to penetrate the cell barrier. It was also possible to demonstrate a transient glucose uptake in the muscle in the constant flow experiments, i.e. when the muscle was suddenly perfused with blood containing a high glucose concentration (? 150 mg/100 ml blood).     

心血管平滑肌收缩和增殖与受体信息传递的关系

心血管平滑肌收缩和增殖与受体信息传递的关系薛全福ＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎＣｏｎｔｒａｃｔｉｏｎａｎｄＰｒｏｌｉｆｅｒａｔｉｏｎｏｆＣａｒｄｉａｃｏｒＶａｓｃｕｌａｒＳｍｏｏｔｈＭｕｓｃｌｅａｎｄＲｅｃｅｐｔｏｒ－Ｓｉｇｎａｌ－Ｔｒａｎｓ...     

肌肉收缩力与收缩速度关系研究

目的:基于肌肉的特殊结构及肌球蛋白工作循环的四态模型,讨论肌肉收缩时收缩力与收缩速度的关系,并通过建立肌肉的力学模型,对力与速度的关系做了进一步讨论。方法:利用化学动力学方法和生化热力学原理,结合肌球蛋白单分子实验结果,从物理学的角度计算肌肉中力与收缩速度的关系。结果:发现力速关系与实验结果完全一致,肌肉中与收缩有关的化学变化可随负荷的变化而自动地进行调节,肌肉收缩时粘滞力与负载有关。结论:此模型可用于讨论肌肉的力与速度的关系,而且物理学方法适用于研究本文体系。     

骨骼肌肌纤维生后发育及肌纤维类型的发育

骨骼肌是人体最大的运动器官,骨骼肌的研究一直为人们所关注.骨骼肌是由不同类型的肌纤维组成,且各种类型的肌纤维具有不同的收缩性质.生后发育过程中肌纤维型的构成对骨骼肌的发育是至关重要的.回顾文献,本文就骨骼肌生后发育,肌纤维分型进行综述.     

Nonlinear Regulation of Capillary Perfusion in Relation to Ambient pO2 Changes in Skeletal Muscle

To study the process of O₂ transport to tissue, we investigated how capillary perfusion is controlled in response to changes in tissue O₂ levels in skeletal muscle. Capillary red blood cell (RBC) velocity and perfused capillary recruitment were measured in rabbit tenuissimus muscle at various ambient oxygen tensions (pO₂) by intravital microscopy. Both RBC velocity and capillary recruitment significantly decreased as the pO₂ level of the suffusate was increased, and the relationship between capillary perfusion, calculated from the velocity and recruitment data, and the pO₂ level of the suffusate clearly yielded a nonlinear correlation that fitted a sigmoidal curve. Capillary perfusion dramatically decreases or increases above or below a suffusate pO₂ level of around 40 Torr, where the O₂ dissociation curve of hemoglobin changes slope. These findings support the hypothesis that microvasculature possesses an intrinsic, effective flow-control mechanism by sensing the metabolic demands of tissue, intimately related to the O₂ saturation of hemoglobin.     

Mechanics of Muscle Injury Induced by Lengthening Contraction

Skeletal muscle is composed of two primary structural components, contractile myofibrils and extracellular matrix (ECM). The myofibrils adhere to the surrounding endomysium through the basal lamina, sarcolemma and dystrophin, and dystrophin associated glycoprotein (DAG). In this study, a novel shear lag type model is developed to investigate the mechanics of injury to the single muscle fiber due to lengthening contractions. A single muscle fiber is considered as a composite system with reinforced by the contractile myofibrils. The lateral linkages between myofibril and endomysium is modeled as a zero thickness coating layer, that could be injured under high interfacial shear stress. The results shows that the degree of the muscle injury is correlated to the magnitude of the passive stretch during the contraction. Dystrophic muscles are more susceptible to contraction induced injury due to lack of DAG complex in lateral linkage.     

The Annual Meeting on Muscle Contraction and Cell Motility

Journal of Muscle Research and Cell Motility -     

Relationship between Lactate Concentrations in Active Muscle Sweat and Whole Blood

Lactate (lactic acid) concentrations in sweat and venous and capillary blood of athletes were measured before and after exercise of the maximum aerobic power. Correlations between the increment of blood and sweat lactate concentrations were found. Lactate concentrations in the sweat can be used for evaluation of changes in blood lactate levels.