蕨菜乙醇提取物的Ames试验研究

目的：研究蕨菜乙醇提取物的致突变作用,为蕨菜的开发利用提供一定依据;方法：制备蕨菜乙醇提取物,采用Ames试验方法,以50μg/皿敌克松作为诱变剂,分别添加提取物50、100、200、400、800μg/皿,统计回变菌落数;结果：受试物各剂量组回变菌落数均未超过自发回变菌落数的2倍,且无剂量-反应关系;结论：在本实验条件下,蕨菜乙醇提取物无致突变作用.     

A semi-automated method for hexahedral mesh construction of human vertebrae from CT scans

Generation of finite element (FE) meshes of vertebrae from computed tomography (CT) scans is labour intensive due to their geometric complexity. As such, techniques that simplify creation of meshes of vertebrae are needed to make FE analysis feasible for large studies and clinical applications. Techniques to obtain a geometric representation of bone contours from CT scans of vertebrae and construct a hexahedral mesh from the contours were developed. An automated edge detection technique was developed to identify surface contours of the vertebrae, followed by atlas based B-spline curve fitting to construct curves from the edge points. The method was automatic and robust to missing data, with a controllable degree of smoothing and interpolation. Parametric mapping was then used to generate nodes for each CT slice, which were connected between slices to obtain a hexahedral mesh. This method could be adapted for modelling a variety of orthopaedic structures.     

Stochastic modelling of wall stresses in abdominal aortic aneurysms treated by a gene therapy

A stochastic mechanical model using the membrane theory was used to simulate the in vivo mechanical behaviour of abdominal aortic aneurysms (AAAs) in order to compute the wall stresses after stabilisation by gene therapy. For that, both length and diameter of AAAs rats were measured during their expansion. Four groups of animals, control and treated by an endovascular gene therapy during 3 or 28 days were included. The mechanical problem was solved analytically using the geometric parameters and assuming the shape of aneurysms by a ‘parabolic–exponential curve’. When compared to controls, stress variations in the wall of AAAs for treated arteries during 28 days decreased, while they were nearly constant at day 3. The measured geometric parameters of AAAs were then investigated using probability density functions (pdf) attributed to every random variable. Different trials were useful to define a reliable confidence region in which the probability to have a realisation is equal to 99%. The results demonstrated that the error in the estimation of the stresses can be greater than 28% when parameters uncertainties are not considered in the modelling. The relevance of the proposed approach for the study of AAA growth may be studied further and extended to other treatments aimed at stabilisation AAAs, using biotherapies and pharmacological approaches.     

Deferoxamine synergistically enhances iron-mediated AP-1 activation: A showcase of the interplay between extracellular-signal-regulated kinase and tyrosine phosphatase

Deferoxamine (DFO) is a drug widely used for iron overload treatment to reduce body iron burden. In the present study, it was shown in mouse epidermal JB6 cells that all iron compounds transiently induced extracellular signal-regulated kinases (ERK) phosphorylation, whereas DFO further enhanced ERK phosphorylation over long periods. The ERK phosphorylation by DFO treatment appears to be due to the inhibition of MAPK phosphatases (MKP) by DFO. The combined effects of iron-initiated MAPK activation and DFO-mediated MKP inhibition resulted in a synergistic enhancement on AP-1 activities. The results indicate that the interplay between MAPK and MKP is important in regulating the extent of AP-1 activation. It is known that administration of DFO in iron overload patients often results in allergic responses at the injection sites. The results suggest that this synergistic AP-1 activation might play a role in DFO-induced skin immune responses of iron overload patients.     

CODON OPTIMIZATION INCREASES HUMAN KALLISTATIN EXPRESSION IN Escherichia coli

A unique serpin, kallistatin, displays vasodilatory, antiangiogenic, anti-inflammatory, and antioxidant activity. Difficulty and low efficacy of obtaining recombinant kallistatin limit the wide investigation of its biological and pathological function. The present study employed a codon optimization algorithm to redesign the kallistatin gene and achieved a high yield of recombinant kallistatin protein. The kallistatin codons were redesigned for a more suitable Escherichia coli host without altering amino acids. Base composition and GC% content were compared between synthetic optimized kallistatin (opti-kallistatin) and wild-type kallistatin (wt-kallistatin). Both opti-kallistatin and wt-kallistatin were purified using Ni-NTA His-binding resins through fast protein liquid chromatography (FPLC). The identity and purity of kallistatin were confirmed by Coomassie blue staining, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and Western blot analysis. The output of opti-kallistatin protein was ～2-fold increase (2.09 ± 0.23 mg/L) compared to wt-kallistatin (1.05 ± 0.2 mg/L). These results suggest that more common codon optimization in the E. coli host significantly increases the yield of heterologous human protein yields. This approach will remarkably facilitate the further investigation of kallistatin in vitro and in vivo.     

DNA methylation profiles provide a viable index for porcine pluripotent stem cells

Porcine induced pluripotent stem cells (iPSCs) provide useful information for translational research. The quality of iPSCs can be assessed by their ability to differentiate into various cell types after chimera formation. However, analysis of chimera formation in pigs is a labor‐intensive and costly process, necessitating a simple evaluation method for porcine iPSCs. Our previous study identified mouse embryonic stem cell (ESC)‐specific hypomethylated loci (EShypo‐T‐DMRs), and, in this study, 36 genes selected from these were used to evaluate porcine iPSC lines. Based on the methylation profiles of the 36 genes, the iPSC line, Porco Rosso‐4, was found closest to mouse pluripotent stem cells among 5 porcine iPSCs. Moreover, Porco Rosso‐4 more efficiently contributed to the inner cell mass (ICM) of blastocysts than the iPSC line showing the lowest reprogramming of the 36 genes (Porco Rosso‐622‐14), indicating that the DNA methylation profile correlates with efficiency of ICM contribution. Furthermore, factors known to enhance iPSC quality (serum‐free medium with PD0325901 and CHIR99021) improved the methylation status at the 36 genes. Thus, the DNA methylation profile of these 36 genes is a viable index for evaluation of porcine iPSCs. genesis 51:763–776. © 2013 Wiley Periodicals, Inc.     

MicroRNA-92a Upholds Bmp Signaling by Targeting noggin3 during Pharyngeal Cartilage Formation

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Highlights? mir92a inactivation leads to loss of pharyngeal cartilages in zebrafish embryos ? mir92a is required for chondrogenic progenitor proliferation and survival ? Bmp signaling is positively regulated by mir92a in the pharyngeal region ? nog3 mRNA is degraded by mir92a to maintain Bmp activity