Spreading area and shape regulate apoptosis and differentiation of osteoblasts

The in vivo observations have indicated that at the remodeling sites of bone, the spreading area or shape of preosteoblasts is confined by the mineralized matrix. But it remains unknown whether this spreading confinement regulates the differentiation or apoptosis of osteoblasts. In the present study, osteoblast-like cells (MC3T3-E1) were seeded on micropatterned islands with different area and shape. The expression of three osteogenic differentiation markers was measured by immunofluorescence staining and apoptotic cells were detected using a terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labelling assay kit. The membrane fluorescence staining results showed that the actual spreading area of micropatterned osteoblasts coincided with the designed value. When the area of a micropatterned cell was confined as 314 or 615 mu m(2), which was lower than that of freely spreading osteoblasts, the circular shape promoted the expression of osteogenic differentiation markers and the percentage of apoptotic osteoblasts compared with the branched shape. This shape-regulated differentiation and apoptosis of osteoblasts with confined spreading area were abolished when actin polymerization was inhibited by cytochalasin D. The present study gives an insight into the roles of spreading morphology on osteoblastic differentiation and apoptosis

The Effect of Cellular Spreading Area and Shape on Apoptosis and Differentiation of Osteoblasts

Abundant evidences has shown that extracellular matrix(ECM) plays critical roles in regulating proliferation and differentiation of cell.In vivo,osteoblasts located on the surface of trabecular bone finally differentiate into osteocytes after being embedded within the mineralized matrix.In additi..

Mathematic model of respiratory mechanics based on monitored physiological parameters

目的建立考虑气血交换的呼吸力学理论模型,将机械通气时血液中的气体含量与呼吸系统的力学规律联系起来。方法考虑循环系统与呼吸过程生理参数的耦合,将常规的临床监护参数(如血液中O2和CO2的气体含量、血红蛋白含量、心率和心输出量等)与肺泡内气体分子数相联系,进而建立力学模型得到气道与肺泡不同时刻的气体含量、压力和流量等动力学参量。结果利用模型估算了呼吸系统不同部位的气体含量,并分析了呼出气体含量对各个待定参数的敏感性。结论本文所发展的呼吸力学模型对利用临床生理监护参数调控机械通气做了初步的尝试,随着后续实验工作的开展将有可能为新型呼吸机的设计和研发提供理论支持

Recent advances in theoretical models of respiratory mechanics

As an important branch of biomedical engineering, respiratory mechanics helps to understand the physiology of the respiratory system and provides fundamental data for developing such clinical technologies as ventilators. To solve different clinical problems, researchers have developed numerous models at various scales that describe biological and mechanical properties of the respiratory system. During the past decade, benefiting from the continuous accumulation of clinical data and the dramatic progress of biomedical technologies (e.g. biomedical imaging), the theoretical modeling of respiratory mechanics has made remarkable progress regarding the macroscopic properties of the respiratory process, complexities of the respiratory system, gas exchange within the lungs, and the coupling interaction between lung and heart. The present paper reviews the advances in the above fields and proposes potential future projects