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Rat bone marrow-derived mesenchymal stem cells were cultured and passaged in vitro. After induction with basic fibroblast growth factor for 24 hours, passage 3 bone marrow-derived mesenchymal stem cells were additionally induced into dopaminergic neurons using three different combinations with basic fibroblast growth factor as follows: 20% Xiangdan injection; all-trans retinoic acid + glial-derived neurotrophic factor; or sonic hedgehog + fibroblast growth factor 8. Results suggest that the bone marrow-derived mesenchymal stem cells showed typical neuronal morphological characteristics after induction. In particular, after treatment with sonic hedgehog + fibroblast growth factor 8, the expressions of nestin, neuron-specific enolase, microtubuleassociated protein 2, tyrosine hydroxylase and vesicular monoamine transporter-2 in cells were significantly increased. Moreover, the levels of catecholamines in the culture supernatant were significantly increased. These findings indicate that Xiangdan injection, all-trans retinoic acid + glial-derived neurotrophic factor, and sonic hedgehog + fibroblast growth factor 8 can all induce dopaminergic neuronal differentiation from bone marrow-derived mesenchymal stem cells. In particular, the efficiency of sonic hedgehog + fibroblast growth factor 8 was highest.

The Aike Qiao group has for nearly two decades focused on the study of biomechanics and simulation engineering, particularly as applied to carotid artery and cerebral aneurysm flows. For this Challenge, CFD simulations were performed by doctor fellow Wenyu Fu, using commercial finite volume solver, ANSYS CFX.Copyright © 2012 by ASME

The objective of this study is to investigate the hemodynamics in patient-specific internal carotid aneurysm and discuss the reason for rupture of aneurysm. A 3-Dimensional pulsatile blood flow in internal carotid with a sidewall aneurysm was studied numerically with the average Reynolds number of 704. Patient-specific model whose parent artery has a large "S" bending and a sidewall aneurysm was constructed from CT data. Unsteady, incompressible, 3-Dimensional Navier-Stokes equations were employed to solve the flow field. The temporal distributions of hemodynamic variables during the cardiac cycle such as streamlines, wall pressure and wall shear stress (WSS) in the arteries and aneurysm were analyzed. From streamlines it can be found that there is an obvious vortex flow in aneurismal cavity in a cardiac cycle. The type of this vortex flow is not changed in a cardiac cycle. As far as Wall Shear Stress, there is a region in aneurismal neck where the value of WSS is relatively high. Growth and rupture mechanism of internal carotid aneurysm in patient can be analyzed based on patient-specific model and hemodynamics simulation.

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 (P0.05), 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 (P0.05). The ratios of Cho/Cr showed no significant difference between the two sides (P0.05). 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.

Endovascular stents with different porosities and wire cross-section shapes may create different effects on the hemodynamics of aneurysm treated with interventional therapy because stents with different wire cross-section shapes induce different flow resistances through the stent strut. In order to analyze the flow resistance of the new stent with triangular cross-section by numerical simulation method, and to provide a reference basis for the structural design and optimization of endovascular stent, four kinds of models of the triangular cross-section bare stent were constructed using SoildWorks 2007 software. Numerical simulations of steady and transient blood flows in the four models were performed respectively according to CFD method using finite element software ANSYS 11. Hemodynamics data in the four models were collected, such as the flow patterns, the distribution of pressure and the flow resistance. The results show that the stent with triangular wire cross-section can produce large resistance of blood inflow to aneurysm and small resistance of outflow from aneurysm. Thus, outflow is easy and inflow is difficult. Thereby blood perfusion and flow of aneurysm cavity is restrained, and the pressure of aneurysm cavity is reduced, which plays certain effect on the intervention treatment of aneurysm. This result provides some instructions for the design of stent structure.

An intracranial aneurysm (IA) is a pathological dilatation of the cerebral artery wall. In clinical practice it is currently widely accepted that maximum diameter of IA is an indicator for patient whether to treat or not. But studies have demonstrated that maximum diameter is not a reliable determinant of IA rupture. According to the theory of strength, if the stress value exceeds the strength limit of material, it will result in failure. So wall stress may be a better indicator to predict aneurismal rupture (failure). Study about wall stress calculated from solid stress model using static pressure has been performed. But blood flow and pressure inside IA are not steady. The dynamic interaction between the unsteady flow and wall may influence the distribution and magnitude of wall stress. The objective of the present study was to compare static and dynamic wall stress analysis of patient specific IA. Patient-specific model of cerebral aneurysm whose host artery has large bending was created from CT data. Simulations about fluid structure interaction model and static structural model were carried out respectively. Commercial software Ansys 11 was used for simulation. The results demonstrated that FSI can change local wall stresses slightly. However, as far as the peak wall stress is concerned, the change of wall stress is negligible. Therefore static structural simulation can be used to predict rupture risk of aneurysm if wall stress was used as an indicator of aneurismal rupture and computational cost can be reduced greatly.

In order to identify the border of STL model with open border, topology structure of STL model was reconstructed using half edge data structure. On this basis, border segments of STL model can be identified by a process of edge traversing. Then constrained Delaunay triangulation with Steiner point insertion was used to triangulate the border regions of STL model. In this way, STL model was closed and it provides necessary foundation to further finite element mesh generation.

Software of 3D reconstructions for medical images is basically focused on the application of visualization. Few people have studied the techniques and software about numerical simulation oriented 3D reconstructions for medical images that mainly solve the problems such as visualization for 3D reconstructions, model modifying and mesh generation for finite element analysis. These issues were reviewed and analyzed, the development toolkits were introduced, and some attentive questions and their corresponding solutions as well as some new perspectives were proposed.

The bacterial chemotaxis adaptor protein CheW physically links the chemoreceptors (MCPs) and the histidine kinase CheA. Extensive investigations using bacterium Escherichia coli have established the central role of CheW in the MCP-modulated activation of CheA. Here we report the solution structure of CheW from E. coli determined by NMR spectroscopy. The results show that E. coli CheW shares an overall fold with previously reported structure of CheW from Thermotoga maritima, whereas local conformational deviations are observed. In particular, the C-terminal alpha-helix is considerably longer in E. coli CheW and appears to shrink the active binding pocket with CheA. Our study provides the structural basis for further investigations in E. coli chemotaxis.

Tributyltin (TBT) is one of the environmental pollutants, which is mostly accumulated in marine animals. The toxic effects of TBT have been extensively documented in several types of cells, but the molecular mechanisms responsible for TBT-induced cell damage are still not fully elucidated. The present study was undertaken to evaluate the apoptotic related biochemical changes in human amnion cells induced by TBT. After cells were exposed to TBT at the concentrations of 1–4 μM for 2 h, the results suggested that TBT could induce an early and typical apoptosis, moreover caspase-3, the modifications of cytoskeletal structure and the Bcl-2 family were involved in this process. The results will deepen our understanding about the toxic mechanism of TBT on human amnion cells.

Previous studies have shown that ultraviolet (UV) A light and the polycyclic aromatic hydrocarbon benzo[ a ]pyrene (BaP) can synergistically enhance the formation of 8-hydroxy-2 ′ deoxyguanosine (8-OHdG) in living cells. It has been postulated that the underlying mechanism is production of reactive oxygen species (ROS) via photosensitization, but direct evidence supporting this hypothesis has been lacking. This study examined intracellular ROS production in living cells co-exposed to UV-A and BaP as well as the relationship between intracellular production of ROS and formation of 8-OHdG. KB cells were exposed to BaP for 24 h, followed by exposure to UV-A (365 nm) or UV-B (312 nm). The levels of intracellular ROS were directly measured by use of the fluorescent probe dihydrorhodamine 123 (DHR-123) in flow cytometry. Levels of 8-OHdG were measured by high performance liquid chromatography coupled with electrochemical detection (HPLC-ECD). The results demonstrated that UV-B itself induced a much greater level of intracellular ROS than did UV-A alone under the same dose of energy (0.10 mW/cm 2 , 20 min). The presence of BaP (13.3 μM) substantially increased ROS production in UV-A-treated cells (2.9-fold), but only slightly enhanced ROS production in UV-B-treated cells (1.3-fold). These results show that BaP acts mainly as a photosensitizer of UV-A, but not UV-B. Furthermore, greater intracellular ROS production was proportional to both BaP concentration and UV-A dosage. There was a linear relationship between ROS production and 8-OHdG formation in cells co-exposed to BaP and UV-A. Results of this study suggest that UV-A and BaP act synergistically to enhance ROS production and formation of 8-OHdG, resulting in increased DNA damage.

To cultivate human mesenchymal stem cells (MSC) derived from fetal bone marrow and examine their pluripotentiality.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.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.Human fetal marrow MSCs were multipotent stem cells.

showing quantification of OARSI score based on Safranin O staining for PBS, PGRN, or Atsttrin-treated ACLT mice (DOCX 56 kb)

showing quantification of OARSI score based on Safranin O staining for PBS, PGRN, or Atsttrin-treated ACLT mice (DOCX 56 kb)

showing expression of PGRN in cartilage at different ages, assayed by immunohistochemistry

showing expression of PGRN in cartilage at different ages, assayed by immunohistochemistry