Numerical simulation of the effect of virtual stent release pose on the expansion results / 生物医学工程学杂志

The current finite element analysis of vascular stent expansion does not take into account the effect of the stent release pose on the expansion results. In this study, stent and vessel model were established by Pro/E. Five kinds of finite element assembly models were constructed by ABAQUS, including 0 degree without eccentricity model, 3 degree without eccentricity model, 5 degree without eccentricity model, 0 degree axial eccentricity model and 0 degree radial eccentricity model. These models were divided into two groups of experiments for numerical simulation with respect to angle and eccentricity. The mechanical parameters such as foreshortening rate, radial recoil rate and dog boning rate were calculated. The influence of angle and eccentricity on the numerical simulation was obtained by comparative analysis. Calculation results showed that the residual stenosis rates were 38.3%, 38.4%, 38.4%, 35.7% and 38.2% respectively for the 5 models. The results indicate that the pose has less effect on the numerical simulation results so that it can be neglected when the accuracy of the result is not highly required, and the basic model as 0 degree without eccentricity model is feasible for numerical simulation.

Finite Element Analysis on Partially Closed and Fully Opened Aortic Valve / 医用生物力学

Objective To explore the effect of different initial state setting on a valve simulation. Methods Two-dimensional structural models were established with the initial state of the aortic valve being partially closed in one model and fully opened in the other. The time-dependent load was applied to the valve and the vessel wall of the aortic and the ventricle sides. The finite element method was used to study the maximum stress, the length of the joint, and the contact force of the closed aortic valve under two different initial states. Results The stress and contact force of the aortic valve were relatively large at the closed position when the initial state was fully opened. The closure degree of the valve was low, and the variations in stress and closure degree were large during the periodic cycle. The stress and contact force of the valve were relatively small when the aortic valve was partially closed. The closure degree was high, and the variations in stress and closure degree of the aortic valve were small during the periodic cycle. Conclusions In the case of the aortic valve partially closed in the initial state, the stability of the calculation process and the closure degree of the valve were relatively high, which should be given more consideration in numerical simulation. The results can be used to study the mechanical behavior of the valve and the biomechanical mechanism of the aortic root.

Ultrasound-guided lauromacrogol sclerotherapy of simple liver cyst：analysis of its efficacy and safety / 介入放射学杂志

Objective To compare the efficacy and safety of lauromacrogol injection sclerotherapy with ethanol injection sclerotherapy in treating simple liver cysts. Methods A total of 166 patients with simple liver cyst were randomly divided into the lauromacrogol group (study group, n=86) and the absolute alcohol group (control group, n=80). Under ultrasonographic guidance, puncture aspiration of liver cyst was carried out in all patients, which was followed by injection of lauromacrogol for patients in the study group or injection of ethanol for patients in the control group. The therapeutic effect and the side-effect were evaluated. The results were compared between the two groups. Results No serious complications such as bleeding or infection occurred in both groups. During the therapeutic course , 45 patients (56.3%) in the control group felt pain to some degree and 23 patients (28.8%) developed drunk-like symptoms, while no patient in the study group felt any obvious discomfort. One week after sclerotherapy , 20 patients (25%) in the control group complained of distending pain on the right upper abdomen, while only 9 patients (10.5%) in the study group complained of pain, and the difference was statistically significant (χ2= 6.073, P 0.05). Conclusion For the treatment of liver cysts, lauromacrogol injection is safe and effective. Therefore, this technique should be recommended in clinical practice.

Biochemical changes in striatum of Parkinson's disease rat model observed by modified proton magnetic resonance spectroscopy / 生物医学工程学杂志

This study was undertaken to observe the biochemical changes in striatum of Parkinson's disease (PD) rat model by modified proton magnetic resonance spectroscopy. 12 SD rats were divided into model (n=7) and control (n=5) groups. At 3 weeks after the injection of 6-hydroxydopamine into right striatum, 1H-MRS on the striatum was taken by modified proton magnetic resonance spectroscopy, and then tyrosine hydroxylase (TH) immunostatining was used to visualize the changes of the neurons in substantia nigra and neurites in striatum. The results showed that TH positive neurons and neurites in the substantia nigra compacts (SNc) and striatum in the normal side of the rat model of PD were decreased (P < 0.05), which proved the successful establishment of PD models. The NAA/Cr ratio of the injected side striatum of model group was lower than that of the normal side (P < 0.05). The ratios of Cho/Cr showed no significant difference between the two sides (P > 0.05). These results indicated that the modified 1.5T 1H-MRS should be a noninvasive technique which could provide useful information about the biochemical metabolites in striatum for the study of PD in rat model.

Exploration of the diversity of postgraduate training model by following medical education law / 中华医学教育探索杂志

Postgraduate education must be systematic and explicit.In recent years,the cultivation of domestic tertiary education for postgraduate students conducted a multi-disciplinary approach.This article give comment on the current postgraduate training objectives,methods,curriculum and training process,training instructors,and puts forward some problems to be discussed in depth.

Culture and pluripotentiality of human marrow mesenchymal stem cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To cultivate human mesenchymal stem cells (MSC) derived from fetal bone marrow and examine their pluripotentiality.</p><p><b>METHODS</b>Bone marrow mononuclear cells from human fetal femur were collected by Percoll gradient centrifugation. The low density cells including MSCs were cultivated and expanded in MSCGM media. The characteristics of the multipotent MSCs were observed by implanting them into nude mice for 4 weeks.</p><p><b>RESULTS</b>Human fetal marrow MSCs were successfully cultivated and differentiated in vivo into many kinds of tissues such as bone, cartilage, adipose, skeletal muscle and tendon-like tissue.</p><p><b>CONCLUSION</b>Human fetal marrow MSCs were multipotent stem cells.</p>

THE EFFECTS OF THE DIFFERENT INDUCERS ON THE DIFFERENTIATION OF RAT BONE-MARROW-DERIVED MESENCHYMAL STEM CELLS TO NEUROCYTES IN VITRO / 解剖学报

0.05).A lot of Nissl bodies in the cell body were seen in induced cells shown by thionine-eosin staining.Conclusion The bone-marrow-derived MSCs can differentiate into neurocytes by either chemical or biological inducers.

MORPHOLOGIC CHARACTERISTICS OF NEURON-LIKE CELLS INDUCED FROM THE RAT BONE MARROW MESENCHYMAL STEM CELLS / 解剖学报

Objective To investigate the morphologic characteristics of neuron-like cells induced from the rat mesenchymal stem cells(MSCs). Methods The rat MSCs from bone marrow were cultured by being adhered to the culture dish.The thirdgeneration of the MSCs were induced by the neonate rat brain homogenate supernatant for 48 hours.The morphological characteristics and the ultrastructures of both non-induced and induced MSCs were observed under the inverted microscope and the electron microscope.The property of the induced cells was identified by using immunocytochemical method. Results Under the inverted microscope MSCs showed spindle or polygon-shaped cell bodies and the nuclei with one or two nucleoli were located in the middle of the cells.After the inducement the cells appeared neuron-like with axonlike and dendrite-like processes.The neuron-like cells were neuron special endolase(NSE),neurofilament protein(NF) positive and glial filbrillary acidic protein(GFAP) negative by irnmunocytochemical staining.Under the electron microscope the MSCs had plentiful cytoplasm and organelles and had an obvious nuclei containing a nucleoli.There were a lot of microvilli on the surfaces of the MSCs.The neuron-like cells had plentiful cytoplasm and irregular nuclei with one to three nucleoli.There were also plenty of microvilli on the cell surfaces.Conclusion MSCs are one kind of multipotent stem cells and can differentiate neurons with matured organelles induced by the neonate rat brain homogenate supernatant.