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| Watered-Down Reform Bill Moving Ahead; CIRM Looking at Boosting Staff to as High as 60
July 7, 2010 at 3:58 PM
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| The California stem cell agency almost certainly will be able to hire a small platoon of additional employees next year as state lawmakers appear ready to remove a voter-imposed staffing cap.
That, however, may sound more troubling than the reality. The agency still has a 6 percent limit on operational spending, which makes the cap of 50 employees both redundant and a bit foolish. CIRM has | | |
| Multi-component extracellular matrices based on peptide self-assembly.
July 7, 2010 at 6:46 AM
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| | Multi-component extracellular matrices based on peptide self-assembly. Chem Soc Rev. 2010 Jul 5; Authors: Collier JH, Rudra JS, Gasiorowski JZ, Jung JP Extracellular matrices (ECMs) are challenging design targets for materials synthesis because they serve multiple biological roles, and they are composed of multiple molecular constituents. In addition, their composition and activities are dynamic and variable between tissues, and they are difficult to study mechanistically in physiological contexts. Nevertheless, the design of synthetic ECMs is a central consideration in applications such as regenerative medicine and 3D cell culture. In order to produce synthetic matrices having both multi-component construction and high levels of compositional definition, strategies based on molecular self-assembly are receiving increasing interest. These approaches are described in this tutorial review and compared with the structures and processes in native ECMs that serve as their inspiration. PMID: 20603663 [PubMed - as supplied by publisher] | | |
| Alternative splicing and muscular dystrophy.
July 7, 2010 at 6:46 AM
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| | Alternative splicing and muscular dystrophy. RNA Biol. 2010 Jul 3;7(4) Authors: Pistoni M, Ghigna C, Gabellini D Alternative splicing of pre-mRNAs is a major contributor to proteomic diversity and to the control of gene expression in higher eukaryotic cells. For this reasons, alternative splicing is tightly regulated in different tissues and developmental stages and its disruption can lead to a wide range of human disorders. The aim of this review is to focus on the relevance of alternative splicing for muscle function and muscle disease. We begin by giving a brief overview of alternative splicing, muscle-specific gene expression and muscular dystrophy. Next, to illustrate these concepts we focus on two muscular dystrophy, myotonic muscular dystrophy and facioscapulohumeral muscular dystrophy, both associated to disruption of splicing regulation in muscle. PMID: 20603608 [PubMed - as supplied by publisher] | | |
| Neuroblastoma and bone metastases: Clinical significance and prognostic value of Dickkopf 1 plasma levels.
July 7, 2010 at 6:46 AM
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| | Neuroblastoma and bone metastases: Clinical significance and prognostic value of Dickkopf 1 plasma levels. Bone. 2010 Jul 2; Authors: Granchi D, Corrias MV, Garaventa A, Baglio SR, Cangemi G, Carlini B, Paolucci P, Giunti A, Baldini N The critical role of the Wnt pathway inhibition in sustaining the onset of bone lesions has been demonstrated in a variety of bone diseases and tumors, and it has been associated with cancer aggressiveness. We have previously demonstrated that neuroblastoma cells express Dickkopf 1 (Dkk1), an inhibitor of the canonical Wnt pathway which prevents the differentiation of bone-forming cells. Since Dkk1 is a secreted factor, it could have potential clinical application as tumor marker for detecting bone metastasis and monitoring of disease. In this study, we investigated the diagnostic and prognostic value of Dkk1 plasma levels in 92 children affected by neuroblastoma, including 32 with bone metastases. Fifty-seven children hospitalized for minor surgical problems served as control group. Circulating levels of Dkk1 were higher in healthy children than in normal adults, and were comparable to those found in adult patients with aggressive tumors. No significant differences were found between neuroblastoma patients and controls, and between patients with and without bone metastases. However, when only patients with metastatic neuroblastoma were considered, the highest Dkk1 levels were detected in patients that poorly responded to induction chemotherapy and in subjects with unamplified MYCN and three or more different metastatic sites. The 'Receiver Operating Characteristic' curve enabled us to identify a threshold value to distinguish patients who were unresponsive to induction treatment. The relationship between Dkk1 and drug resistance was supported by in vitro experiments, since an increased sensitivity to doxorubicin was found in neuroblastoma cells releasing low Dkk1 levels, either constitutively or experimentally following the treatment with specific siRNA. In conclusion, Dkk1 is released by neuroblastoma cells and is able to affect the balance between osteoblastogenesis and osteoclastogenesis, thus favoring the onset of osteolytic metastases. Nevertheless, Dkk1 plasma levels do not allow the detection of bone lesions in neuroblastoma, but seem to have a predictive value with regard to the severity and the prognosis of the disease in a subset of patients with metastatic tumor. New knowledge on the biological role of Dkk1 in driving the natural history of neuroblastoma has to be further investigated, and could help to establish specific therapeutic strategies able to target key factors of tumor progression. PMID: 20603237 [PubMed - as supplied by publisher] | | |
| The influence of covalently linked and free polyethylene glycol on the structural and release properties of rhBMP-2 loaded microspheres.
July 7, 2010 at 6:46 AM
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| | The influence of covalently linked and free polyethylene glycol on the structural and release properties of rhBMP-2 loaded microspheres. J Control Release. 2010 Jul 2; Authors: Lochmann A, Nitzsche H, von Einem S, Schwarz E, Mäder K The current clinical success of therapies with recombinant human Bone Morphogenetic Protein 2 (rhBMP-2) is limited due to inefficient delivery. The high doses applied have frequently been related to severe adverse effects such as tissue swelling, seroma, inflammatory effects and heterotopic ossification. The controlled delivery of lower doses is supposed to reduce adverse effect incidence as well as costs. In this study, novel polyethylene glycol - poly(lactic-co-glycolic) acid (PEG-PLGA) diblock copolymers were used to produce low dose controlled delivery vehicles for rhBMP-2. A method to fabricate a variety of microsphere formulations with a high encapsulation efficiency in high yields was developed. The influence of PEG as an inner phase cosolvent and linked PLGA as copolymer was investigated. Six different microsphere systems with varying PEG amounts in both core and shell were characterised thoroughly with respect to the specific properties of rhBMP-2. The particle size of the microspheres was investigated with both laser diffraction and environmental scanning electron microscopy. Higher PEG/PLGA ratios showed a tendency to increase in size and a wider distribution. Due to the low rhBMP-2 doses, a profound characterisation was very challenging. The growth factor was covalently attached to rhodamine B for the first time. Studies on drug distribution in the microspheres were performed by means of confocal laser scanning microscopy. The addition of PEG to the inner phase was found to impair the formation of spherical microdomains with localized higher growth factor concentrations. Release profiles, determined with ELISA, were linked to the structural changes that were monitored. Distinct, controlled release profiles were achieved in all formulations and showed that PEG is a versatile tool in the effective control of release rates from microspheres. Higher PEG/PLGA ratios in the polymer were shown to increase the release rate from the microspheres. In contrast, PEG administered to the inner phase decreased the release rate. The biological activity of released protein was shown in vitro in an alkaline phosphatase assay. It was demonstrated that PEG-PLGA microspheres are a promising sustained delivery system which allows a reduction of the required rhBMP-2 dose to limit both adverse effects and costs. Furthermore, the data indicated that the use of PEG as an inner phase cosolvent is not suitable for rhBMP-2 in contrast the reported beneficial effects for other growth factors. PMID: 20603166 [PubMed - as supplied by publisher] | | |
| Carrier-free epithelial cell sheets prepared by enzymatic degradation of collagen gel.
July 7, 2010 at 6:18 AM
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| | Carrier-free epithelial cell sheets prepared by enzymatic degradation of collagen gel. J Tissue Eng Regen Med. 2010 Jul 5; Authors: Ke Q, Wang X, Gao Q, Wu Z, Wan P, Zhan W, Ge J, Wang Z Limbal stem-cell deficiency by ocular trauma or disease causes corneal opacification and vision loss. Conventional tissue engineering using biodegradable scaffolds has met with limited success. In this study, we developed a novel method for preparing carrier-free epithelial cell sheets, which have potential for use in repairing defects of the ocular surface. Stratified corneal epithelial cell sheets were prepared in culture dishes coated with biodegradable type I collagen. Haematoxylin and eosin staining, electron microscopy and immunohistochemistry were performed to characterize the cell sheets. Then, carrier-free epithelial sheets were successfully engineered using specific collagenase to degrade the collagen gel. Cell sheets of four to six cell layers after culture for 14 days were similar to natural rabbit corneal epithelia, as shown by pathological examination. Microvillus, tight cell-cell junctions and desmosome junctions were observed via electron microscopy. K3 and basement membrane components, such as type IV collagen and laminin, were expressed in the cells sheets and integrin beta1 was maintained in basal cells. This novel method of using collagenase to degrade collagen gel is both simple and effective in preparing intact carrier-free epithelial cell sheets. Such sheets have great potential for application during in vivo corneal regeneration. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20603893 [PubMed - as supplied by publisher] | | |
| Interaction between electrical stimulation, protein coating and matrix elasticity: a complex effect on muscle fibre maturation.
July 7, 2010 at 6:18 AM
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| | Interaction between electrical stimulation, protein coating and matrix elasticity: a complex effect on muscle fibre maturation. J Tissue Eng Regen Med. 2010 Jul 5; Authors: Boonen KJ, van der Schaft DW, Baaijens FP, Post MJ In skeletal muscle tissue engineering, it remains a challenge to produce mature, functional muscle tissue. Mimicking the in vivo niche in in vitro culture might overcome this problem. Niche components include, for example, extracellular matrix proteins, neighbouring cells, growth factors and physical factors such as the elasticity of the matrix. Previously, we showed the effects of matrix stiffness and protein coating on proliferation and differentiation of muscle progenitor cells in a two-dimensional (2D) situation. In the present study we have investigated the additional effect of electrical stimulation. More precisely, we investigated the effect of electrical stimulation on primary myoblast maturation when cultured on top of Matrigel()- or laminin-coated substrates with varying elasticities. The effect of electrical stimulation on differentiation and maturation was found to be dependent on coating and stiffness. Although electrical stimulation enhanced myoblast maturation, the effect was mild. We therefore conclude that, with the current regimen, electrical stimulation is not essential to create functional, mature muscle tissue. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20603881 [PubMed - as supplied by publisher] | | |
| Tissue spheroid fusion-based in vitro screening assays for analysis of tissue maturation.
July 7, 2010 at 6:18 AM
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| | Tissue spheroid fusion-based in vitro screening assays for analysis of tissue maturation. J Tissue Eng Regen Med. 2010 Jul 5; Authors: Hajdu Z, Mironov V, Mehesz AN, Norris RA, Markwald RR, Visconti RP Organ printing or computer-aided robotic layer-by-layer additive biofabrication of thick three-dimensional (3D) living tissue constructs employing self-assembling tissue spheroids is a rapidly evolving alternative to classic solid scaffold-based approaches in tissue engineering. However, the absence of effective methods of accelerated tissue maturation immediately after bioprinting is the main technological imperative and potential impediment for further progress in the development of this emerging organ printing technology. Identification of the optimal combination of factors and conditions that accelerate tissue maturation ('maturogenic' factors) is an essential and necessary endeavour. Screening of maturogenic factors would be most efficiently accomplished using high-throughput quantitative in vitro tissue maturation assays. We have recently reviewed the formation of solid scaffold-free tissue constructs through the fusion of bioprinted tissue spheroids that have measurable material properties. We hypothesize that the fusion kinetics of these tissue spheroids will provide an efficacious in vitro assay of the level of tissue maturation. We report here the results of experimental testing of two simple quantitative tissue spheroid fusion-based in vitro high-throughput screening assays of tissue maturation: (a) a tissue spheroid envelopment assay; and (b) a tissue spheroid fusion kinetics assay. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20603872 [PubMed - as supplied by publisher] | | |
| Tensile strain and magnetic particle force application do not induce MAP3K8 and IL-1B differential gene expression in a similar manner to fluid shear stress in human mesenchymal stem cells.
July 7, 2010 at 6:18 AM
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| | Tensile strain and magnetic particle force application do not induce MAP3K8 and IL-1B differential gene expression in a similar manner to fluid shear stress in human mesenchymal stem cells. J Tissue Eng Regen Med. 2010 Jul 5; Authors: Glossop JR, Cartmell SH Mechanical forces, important in a variety of cellular processes, including proliferation, differentiation and gene expression, are also key in the development, remodelling and maintenance of load-bearing tissues such as cartilage and bone. Thus, there is great interest in using in vitro mechanical conditioning of mesenchymal stem cells (MSCs), multipotent adult stem cells, for tissue engineering of these tissues. In a previous gene expression study, we reported a potentially important role for mitogen-activated protein kinase kinase kinase 8 (MAP3K8) and interleukin-1beta (IL-1B) in MAPK signalling in MSCs exposed to fluid shear stress. In this follow-up study, we examined the expression of these genes in MSCs exposed to other types of mechanical force: uniaxial tensile strain (3% cell elongation) and forces generated through the exposure of magnetic particle-labelled MSCs to an oscillating magnetic field (maximum field strength 90 mT). Exposure to both types of mechanical force for 1 h did not significantly alter the gene expression of MAP3K8 or IL-1B over the 24 h period subsequent to force exposure. These data demonstrate that uniaxial tensile strain and magnetic particle-based forces do not induce MAP3K8-related MAPK signalling in the same manner as does fluid flow-induced shear stress. This illustrates divergence in the process of mechanotransduction in mechanically stimulated MSCs. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20603871 [PubMed - as supplied by publisher] | | |
| Using swept-source optical coherence tomography to monitor the formation of neo-epidermis in tissue-engineered skin.
July 7, 2010 at 6:18 AM
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| | Using swept-source optical coherence tomography to monitor the formation of neo-epidermis in tissue-engineered skin. J Tissue Eng Regen Med. 2010 Jul 5; Authors: Smith LE, Bonesi M, Smallwood R, Matcher SJ, Macneil S There is an increasing need for a robust, simple to use, non-invasive imaging technology to follow tissue-engineered constructs as they develop. Our aim was to evaluate the use of swept-source optical coherence tomography (SS-OCT) to image tissue-engineered skin as it developed over several weeks. Tissue-engineered skin was produced using both de-epithelialized acellular dermis (DED) and amorphous collagen gels. In both cases the epidermis could be readily distinguished from the neodermis, based on a comparison with standard destructive histology of samples. Constructs produced with DED showed more epidermal/dermal maturation than those produced using collagen. The development of tissue-engineered skin based on DED was accurately monitored with SS-OCT over 3 weeks and confirmed with conventional histology. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20603865 [PubMed - as supplied by publisher] | | |
| Preparing nano-calcium phosphate particles via a biologically friendly pathway.
July 7, 2010 at 6:18 AM
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| | Preparing nano-calcium phosphate particles via a biologically friendly pathway. Biomed Mater. 2010 Jul 6;5(4):041001 Authors: Hu Q, Ji H, Liu Y, Zhang M, Xu X, Tang R It is widely agreed that nano-calcium phosphates (CaP) play an important role in tissue engineering and medical application due to their unique biological characteristics. However, the properties of nano-CaP, including bioactivity, biocompatibility and mechanical properties, are tailored over wide ranges by controlling the size and morphology of particles. Therefore, it is important to develop synthesis methods which can control the particle size distribution and shape uniformly. In this study, we report that polyacrylic acid (PAA) can act as an efficient agent to modulate nano-CaP formation. The dimension of the resultant sphere-like nanoparticles (5-60 nm) can readily be regulated by changing PAA concentrations (75-200 microg ml(-1)). In contrast to other additives, PAA is a water-soluble polymer that has already been used as an excellent biocompatible implant material in vivo. Our in vitro proliferation experiments of bone marrow mesenchymal stem cells (BMSCs) demonstrate that the involvement of PAA does not change the bioactivity of the resultant nano-CaP. In contrast, the nano-CaP fabricated by using another typical control agent, hexadecyl (cetyl) trimethyl ammonium bromide, suppressed the cell proliferation of BMSCs. Thus, we suggest that the biopolymer, PAA, can provide a more biologically friendly pathway to prepare biological nano-CaP for biomedical application. PMID: 20603529 [PubMed - as supplied by publisher] | | |
| Autologous matrix-induced chondrogenesis (AMIC). A one-step procedure for retropatellar articular resurfacing.
July 7, 2010 at 6:18 AM
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| | Autologous matrix-induced chondrogenesis (AMIC). A one-step procedure for retropatellar articular resurfacing. Acta Orthop Belg. 2010 Apr;76(2):260-3 Authors: Benthien JP, Behrens P The objective of this technical note is to describe the autologous matrix induced chondrogenesis (AMIC) procedure and to evaluate its possible role for resurfacing of retropatellar cartilage defects. AMIC is a one-step procedure combining microfracturing with application of a collagen I/III membrane to protect the initial blood clot and to serve as a scaffold for the developing chondrocytes. A retrospective analysis of our experience in three patients followed for 18 months is presented. PMID: 20503954 [PubMed - indexed for MEDLINE] | | | | 
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