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| Eccentric contractions induce rapid isometric torque drop in dystrophin-deficient dogs.
June 15, 2010 at 8:02 AM
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| | Eccentric contractions induce rapid isometric torque drop in dystrophin-deficient dogs. Muscle Nerve. 2010 May 7; Authors: Tegeler CJ, Grange RW, Bogan DJ, Markert CD, Case D, Kornegay JN, Childers MK We tested the hypothesis that eccentric contractions (ECCs) rapidly induce greater-than-normal isometric torque drop in dystrophin-deficient golden retriever muscular dystrophy (GRMD) muscles. ECCs were imposed by forcibly stretching activated muscles. The results indicate that isometric torque drop was greater in GRMD versus controls (P < 0.0001). Our findings support the hypothesis that ECCs induce greater-than-normal isometric torque drop in GRMD muscles. The magnitude of ECC-induced isometric torque loss may be an ideal clinical endpoint in the GRMD model. Muscle Nerve, 2010. PMID: 20544944 [PubMed - as supplied by publisher] | | |
| Glial cell line-derived neurotrophic factor-secreting genetically modified human bone marrow-derived mesenchymal stem cells promote recovery in a rat model of Parkinson's disease.
June 15, 2010 at 8:02 AM
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| | Glial cell line-derived neurotrophic factor-secreting genetically modified human bone marrow-derived mesenchymal stem cells promote recovery in a rat model of Parkinson's disease. J Neurosci Res. 2010 Jun 11; Authors: Glavaski-Joksimovic A, Virag T, Mangatu TA, McGrogan M, Wang XS, Bohn MC Parkinson's disease (PD) is a neurodegenerative disease characterized by progressive degeneration of nigrostriatal dopaminergic (DA) neurons. The therapeutic potential of glial cell line-derived neurotrophic factor (GDNF), the most potent neurotrophic factor for DA neurons, has been demonstrated in many experimental models of PD. However, chronic delivery of GDNF to DA neurons in the brain remains an unmet challenge. Here, we report the effects of GDNF-releasing Notch-induced human bone marrow-derived mesenchymal stem cells (MSC) grafted into striatum of the 6-hydroxydopamine (6-OHDA) progressively lesioned rat model of PD. Human MSC, obtained from bone marrow aspirates of young, healthy adult volunteers, were transiently transfected with the intracellular domain of the Notch1 gene (NICD) to generate SB623 cells. SB623 cells expressing GDNF and/or humanized Renilla green fluorescent protein (hrGFP) following lentiviral transduction or nontransduced cells were stereotaxically placed into rat striatum 1 week after a unilateral partial 6-OHDA striatal lesion. At 4 weeks, rats that had received GDNF-transduced SB623 cells had significantly decreased amphetamine-induced rotation compared with control rats, although this effect was not observed in rats that received GFP-transduced or nontransduced SB623 cells. At 5 weeks, rejuvenated tyrosine hydroxylase-immunoreactive (TH-IR) fibers that appeared to be host DA axons were observed in and around grafts. This effect was more prominent in rats that received GDNF-secreting cells and was not observed in controls. These observations suggest that human bone-marrow derived MSC, genetically modified to secrete GDNF, hold potential as an allogeneic or autologous stem cell therapy for PD. (c) 2010 Wiley-Liss, Inc. PMID: 20544825 [PubMed - as supplied by publisher] | | |
| Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. I. Preparation and in vitro degradation.
June 15, 2010 at 8:02 AM
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| | Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. I. Preparation and in vitro degradation. J Biomed Mater Res A. 2010 Jun 11; Authors: Fu Q, Rahaman MN, Fu H, Liu X Bioactive glass scaffolds with a microstructure similar to that of dry human trabecular bone but with three different compositions were evaluated for potential applications in bone repair. The preparation of the scaffolds and the effect of the glass composition on the degradation and conversion of the scaffolds to a hydroxyapatite (HA)-type material in a simulated body fluid (SBF) are reported here (Part I). The in vitro response of osteogenic cells to the scaffolds and the in vivo evaluation of the scaffolds in a rat subcutaneous implantation model are described in Part II. Scaffolds (porosity = 78-82%; pore size = 100-500 mum) were prepared using a polymer foam replication technique. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO(2) content of 13-93 was replaced by B(2)O(3), respectively. The conversion rate of the scaffolds to HA in the SBF increased markedly with the B(2)O(3) content of the glass. Concurrently, the pH of the SBF also increased with the B(2)O(3) content of the scaffolds. The compressive strengths of the as-prepared scaffolds (5-11 MPa) were in the upper range of values reported for trabecular bone, but they decreased markedly with immersion time in the SBF and with increasing B(2)O(3) content of the glass. The results show that scaffolds with a wide range of bioactivity and degradation rate can be achieved by replacing varying amounts of SiO(2) in silicate bioactive glass with B(2)O(3). (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010. PMID: 20544804 [PubMed - as supplied by publisher] | | |
| Stem cell therapy - Hype or hope? A review.
June 15, 2010 at 8:02 AM
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| | Stem cell therapy - Hype or hope? A review. J Conserv Dent. 2009 Oct;12(4):131-8 Authors: Nadig RR While the regeneration of a lost tissue is known to mankind for several years, it is only in the recent past that research on regenerative medicine/dentistry has gained momentum and eluded the dramatic yet scientific advancements in the field of molecular biology. The growing understanding of biological concepts in the regeneration of oral/dental tissues coupled with experiments on stem cells is likely to result in a paradigm shift in the therapeutic armamentarium of dental and oral diseases culminating in an intense search for "biological solutions to biological problems." Stem cells have been successfully isolated from variety of human tissues including orofacial tissues. Initial evidence from pioneering studies has documented the likely breakthrough that stem cells offer for various life-threatening diseases that have so far defeated modern medical care. The evidence gathered so far has propelled many elegant studies exploring the role of stem cells and their manifold dental applications. This review takes you on a sojourn of the origin of stem cells, their properties, characteristics, current research, and their potential applications. It also focuses on the various challenges and barriers that we have to surmount before translating laboratory results to successful clinical applications heralding the dawn of regenerative dentistry. PMID: 20543921 [PubMed - in process] | | |
| Reconstruction of the midface and maxilla.
June 15, 2010 at 8:02 AM
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| | Reconstruction of the midface and maxilla. Curr Opin Otolaryngol Head Neck Surg. 2010 Jun 10; Authors: Oʼconnell DA, Futran ND PURPOSE OF REVIEW: To review all pertinent topics related to midface and maxillary reconstruction including current classification schemes and reconstructive techniques. RECENT FINDINGS: The maxilla represents the functional and aesthetic cornerstone of the midface region. Defects in this area represent a unique challenge to the reconstructive surgeon as the complex anatomy of this area can be challenging to repair and reconstruct. The current indications as well as advantages and disadvantages of different reconstructive approaches are reviewed here in order to provide reconstructive surgeons with optimal information for surgical and clinical decision making in this challenging patient population. Recent developments in midface reconstruction options including near total facial transplant as well as tissue engineering techniques are also reviewed. SUMMARY: Multiple reconstructive pathways can be followed in restoring maxillary and midface defects. The surgeon and rest of the reconstructive team must make individualized decisions based on the nature of the defect as well as the specific needs and concerns of the patient when selecting the optimal reconstructive approach for each patient. PMID: 20543697 [PubMed - as supplied by publisher] | | |
| [Stem cell therapy for cerebral ischemia.]
June 15, 2010 at 8:02 AM
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| | [Stem cell therapy for cerebral ischemia.] No Shinkei Geka. 2010 Jun;38(6):515-20 Authors: Honmou O, Houkin K PMID: 20543224 [PubMed - in process] | | |
| Epoxy-amine synthesised hydrogel scaffolds for soft-tissue engineering.
June 15, 2010 at 8:02 AM
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| | Epoxy-amine synthesised hydrogel scaffolds for soft-tissue engineering. Biomaterials. 2010 Jun 7; Authors: Hamid ZA, Blencowe A, Ozcelik B, Palmer JA, Stevens GW, Abberton KM, Morrison WA, Penington AJ, Qiao GG Highly porous and biodegradable hydrogels based on poly(ethylene glycol) (PEG) and cystamine (Cys) were fabricated using epoxy-amine chemistry and investigated as scaffolds for soft-tissue engineering. Whereas the application of fused-salt templates provided a comprehensive interconnecting pore morphology, the incorporation of a specially designed poly(epsilon-caprolactone) (PCL) cross-linker provided enhanced mechanical function without adversely effecting the scaffolds positive biological interactions. The addition of only 1.2 wt% of the PCL cross-linker was sufficient to provide improvements in the ultimate stress of 30-40%. In vitro studies not only confirmed the non-cytotoxic nature of the scaffolds, but also their degradation products, which were isolated and characterised by nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionisation time-of-flight mass spectroscopy (MALDI ToF MS). In vivo trials were conducted over a period of 8 weeks through implantation of the scaffolds into the dorsal region of rats. At both 2 and 8 week time points the explants revealed complete infiltration by the surrounding tissue and the development of a vascular network to support the newly generated tissue, without an excessive foreign-body response. PMID: 20542558 [PubMed - as supplied by publisher] | | |
| Scaffold microarchitecture determines internal bone directional growth structure: A numerical study.
June 15, 2010 at 8:02 AM
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| | Scaffold microarchitecture determines internal bone directional growth structure: A numerical study. J Biomech. 2010 Jun 11; Authors: Sanz-Herrera JA, Doblaré M, GarcÃa-Aznar JM A number of successful results have been reported in bone tissue engineering, although the routine clinical practice has not been reached so far. One of the reasons is the poor understanding of the role of each scaffold design parameter in its functional performance, which yields an uncertain outcome of each clinical application. Specifically, the role of internal scaffold microarchitectural shape on the regeneration rate and distribution of newly formed bone is still unknown. This work is focused on the in-silico determination of the role of scaffold microstructural anisotropy in bone tissue regeneration. A multiscale approach of the problem is established distinguishing between macroscopic region domain (bone organ and scaffold) and microscopic domain (scaffold microstructure). Results show that, once the scaffold microstructure is properly interconnected and the porosity is sufficiently high, similar rates of bone regeneration are found. However, the main conclusion of the work is that initial scaffold microstructural anisotropy has important consequences since it determines the spatial distribution of the newly formed tissue. PMID: 20542275 [PubMed - as supplied by publisher] | | |
| Carbodiimide cross-linked amniotic membranes for cultivation of limbal epithelial cells.
June 15, 2010 at 8:02 AM
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| | Carbodiimide cross-linked amniotic membranes for cultivation of limbal epithelial cells. Biomaterials. 2010 Jun 10; Authors: Ma DH, Lai JY, Cheng HY, Tsai CC, Yeh LK In ophthalmic tissue engineering, amniotic membrane (AM) is one of the most prevalent natural matrices used for limbal epithelial cell (LEC) cultivation and transplantation. However, the application of AM as a scaffold is limited by its low biomechanical strength and rapid biodegradation. The present study reports the development of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) cross-linked AM as an LEC carrier. The collagenous tissue materials were modified with varying cross-linker concentrations (0-0.25 mmol EDC/mg AM) and were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), ninhydrin assays, electron microscopy, light transmission measurements, mechanical and in vitro degradation tests, as well as diffusion permeability and cell culture studies. Our results showed that chemical cross-linking approaches saturation at concentrations of 0.05 mmol EDC/mg AM. The formation of cross-links (i.e., amide bonds) in the samples treated with 0.05 mmol EDC/mg AM may cause significant aggregation of tropocollagen molecules and collagen microfibrils without affecting cell morphology of biological tissues. With the optimum concentration of 0.05 mmol EDC/mg AM, chemical cross-linker could significantly enhance the mechanical and thermal stability, optical transparency, and resistance to collagenase digestion. Continuous permeation of albumin through the cross-linked AM would be helpful to cell growth over the matrix surface. In addition, the EDC cross-linked samples were able to support LEC proliferation and preserve epithelial progenitor cells in vitro and in vivo. It is concluded that the AM cross-linked with 0.05 mmol EDC/mg AM may be a potential biomaterial for regenerative medicine. PMID: 20541801 [PubMed - as supplied by publisher] | | |
| Bioengineering endothelialized neo-corneas using donor-derived corneal endothelial cells and decellularized corneal stroma.
June 15, 2010 at 8:02 AM
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| | Bioengineering endothelialized neo-corneas using donor-derived corneal endothelial cells and decellularized corneal stroma. Biomaterials. 2010 Jun 10; Authors: Choi JS, Williams JK, Greven M, Walter KA, Laber PW, Khang G, Soker S Corneal transplantation is a common transplant procedure performed to improve visual acuity by replacing the opaque or distorted host tissue by clear healthy donor tissue. However, its clinical utility is limited due to a lack of high quality donor corneas. Bioengineered neo-corneas, created using an expandable population of human donor-derived corneal endothelial cells (HCEC), could address this current shortage. The objectives of this study were to establish HCEC isolation and culture protocols and to investigate the feasibility of bioengineering corneal tissue constructs by seeding the cells on decellularized human corneal stroma. HCECs were removed from the discarded corneas of eye donors by enzymatic digestion. Cells were expanded and evaluated for their expression of Na(+)/K(+)-ATPase and zona occludens-1 (ZO-1). Donor corneal stromas were cut to 120-200 mum thickness slices using a microtome and then decellularized. Extracellular matrix components and mechanical properties of the scaffolds were measured after decellularization. To engineer neo-corneas, 130 HCEC/mm(2) were seeded on decellularized human corneal stromas. The resulting constructs were placed in growth medium for 14 days and then analyzed using scanning electron microscopy (SEM), histology, and immunocytochemistry. Seeded cells retain expression of the functional markers Na(+)/K(+)-ATPase and ZO-1 and constructs have biomechanical properties similar to those of normal corneas. These results indicate that construction of neo-corneas, using HCECs derived from discarded donor corneas and decellularized thin-layer corneal stromas, may create a new source of high quality corneal tissue for transplantation. PMID: 20541797 [PubMed - as supplied by publisher] | | |
| Stem cells and regenerative medicine in urology, part 2: urothelium, urinary bladder, urethra and prostate.
June 15, 2010 at 8:02 AM
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| | Stem cells and regenerative medicine in urology, part 2: urothelium, urinary bladder, urethra and prostate. Actas Urol Esp. 2010 Jul;34(7):592-597 Authors: Pastor-Navarro T, Beamud-Cortés M, Fornas-Buil E, Moratalla-Charcos LM, Osca-GarcÃa JM, Gil-Salom M INTRODUCTION: Investigation in cell therapy and regenerative medicine, mainly developed around stem cell research, is reaching promising results in every medical specialities. There are also being great advances in Urology, despite the difficulties researchers are facing, as complete identification and isolation of human urothelial and prostatic stem cells has not been possible yet, although many groups are close to achieve it. MATERIAL AND METHODS: We performed an electronic research through the Pubmed database, of both original and review publications, with the following search criteria: "stem cells urology", "urothelial stem cells", "bladder stem cells", "prostate stem cells", "urethra stem cells", "cell therapy urology", "tissue engeneering urology" y "regenerative medicine urology". RESULTS: We reviewed 30 articles published up to November 2009, trying to summarize thoroughly the most relevant findings and the last advances in this fild, from the first steps to this day. CONCLUSION: Despite the great lack of knowledge existing, especially the need for achieving the identification of kidney, urothelium and prostate stem cells, this shouldn't prevent researchers from translating the laboratory results to the clinical work. PMID: 20540875 [PubMed - as supplied by publisher] | | |
| Vitiligo: Pathogenetic Hypotheses and Targets for Current Therapies.
June 15, 2010 at 8:02 AM
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| | Vitiligo: Pathogenetic Hypotheses and Targets for Current Therapies. Curr Drug Metab. 2010 Jun 11; Authors: Guerra L, Dellambra E, Brescia S, Raskovic D Vitiligo is a multifactorial disorder characterized by the appearance of white maculae that may spread over the entire body skin. Depigmentation arises from the loss of functioning melanocytes. Non segmental vitiligo (NSV) is the most common form of the disease: it is usually progressive and may be associated with familiarity and autoimmunity. Segmental vitiligo (SV) frequently stabilizes few years after its onset. Vitiligo etiology involves multiple pathogenetic factors, most of them working in concert. Impaired antioxidative defences lead to accumulation of reactive oxygen species (ROS), which affect melanocytes. Mitochondrial membrane lipid peroxidation may participate to ROS overproduction. A temporal sequence may connect oxidative stress and autoimmunity. Overall, a genetic predisposition renders vitiligo melanocytes more susceptible to precipitating factors than normal healthy melanocytes. The definition of isolated or superimposed manifestations of polygenic skin disorders has been proposed for SV and SV-NSV association. Keratinocytes and melanocytes are both affected and apoptosis, ageing or melanocythorragy are the ultimate effects of the complex deregulation in vitiligo skin. Pathogenetic therapies mainly act by inducing immunosuppression and stimulation of melanocyte proliferation and migration. Here the most popular hypotheses for the pathogenesis of vitiligo are summarized. Fundamental cellular, biochemical and molecular alterations accounting for melanocyte destruction in vitiligo are also described. Last, pathogenetic approaches in the treatment of such a complex disease are discussed, with particular consideration on the cellular and molecular targets of the current therapies. PMID: 20540698 [PubMed - as supplied by publisher] | | |
| [Experimental study on construction of neurotization tissue engineered bone for repairing large bone defects in rabbit]
June 15, 2010 at 8:02 AM
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| | [Experimental study on construction of neurotization tissue engineered bone for repairing large bone defects in rabbit] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 May;24(5):599-605 Authors: Jiang S, Liu Y, Wang Q, Zhao P, Mu T, Wang L, Qin J, Chen S, Pei G OBJECTIVE: Construction of viable tissue engineered bone is one of the most important research fields in the clinical application of bone tissue engineering, to investigate the function of nerve factors in bone tissue engineering by cell detection in vitro and construction of neurotization tissue engineered bone in vivo. METHODS: Fifty-four healthy New Zealand white rabbits, male or female, weighing 2-3 kg, were involved in this study. Bone marrow mesenchymal stem cells (BMSCs) from the bone marrow of white rabbits were cultured. The second passage of BMSCs were treated with sensory nerve or motor nerve homogenates, using the LG-DMEM complete medium as control. The proliferation and osteogenic differentiation of the cells were observed and tested by the MTT assay, alkaline phosphatase (ALP) stain, and collagen type I immunocytochemistry identification. The osteogenic induced BMSCs were inoculated in beta tricalcium phosphate (beta-TCP) biomaterial scaffold and cultured for 72 hours, then the beta-TCP loaded with seed cells was implanted in the rabbit femur with 15 mm bone and periosteum defects. Fifty-four New Zealand white rabbits were randomly divided into three groups (n = 18): sensory nerve bundle (group A) or motor nerve bundle (group B) were transplanted into the side groove of beta-TCP scaffold, group C was used as a control without nerve bundle transplantation. X-ray detection was performed at the 4th, 8th, and 12th weeks after operation. Bone mineral density (BMD) detection and S-100, calcitonin gene-related peptide (CGRP) immunohistochemistry stain were used at the 12th week to evaluate the effects of bone formation and discuss the mechanism. RESULTS: MTT assay indicated that the absorbance (A) value of each group increased with culture time. From the 6th day, the A values of both the sensory nerve and motor nerve homogenate groups were lower than that of the control group, showing significant difference (P < 0.01). On the 8th and 10th days, the A value of the sensory nerve homogenate group was lower than that of the motor nerve homogenate group, showing significant difference (P < 0.05). ALP stain and collagen type I immunocytochemistry identification indicated that the positive cells in both the sensory nerve and motor nerve homogenate groups were less than that of control group after culturing 7 days. And the positive expression of collagen type I was just visible in the cells of control group. The Yang's scores increased gradually in three groups, the score of group A was significantly higher than those of group B and group C (P < 0.01) at the 8th week. The BMD value of group A was significantly higher than those of group B and group C (P < 0.01) at the 12th week. The S-100 and CGRP expressions were high in group A, and low in group B and group C. CONCLUSION: Homogenates of sensory nerve and motor nerve have inhabitory effects on the proliferation and osteogenic differentiation of BMSCs. The osteogenesis and remodeling of the neurotization tissue engineered bone are more closely related with sensory nerves. PMID: 20540269 [PubMed - in process] | | |
| Heat shock protein 70B' (HSP70B') expression and release in response to human oxidized low density lipoprotein immune complexes in macrophages.
June 15, 2010 at 8:02 AM
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| | Heat shock protein 70B' (HSP70B') expression and release in response to human oxidized low density lipoprotein immune complexes in macrophages. J Biol Chem. 2010 May 21;285(21):15985-93 Authors: Smith KJ, Twal WO, Soodavar F, Virella G, Lopes-Virella MF, Hammad SM Heat shock proteins (HSPs) have been implicated in the activation and survival of macrophages. This study examined the role of HSP70B', a poorly characterized member of the HSP70 family, in response to oxidatively modified LDL (oxLDL) and immune complexes prepared with human oxLDL and purified human antibodies to oxLDL (oxLDL-IC) in monocytic and macrophage cell lines. Immunoblot analysis of cell lysates and conditioned medium from U937 cells treated with oxLDL alone revealed an increase in intracellular HSP70B' protein levels accompanied by a concomitant increase in HSP70B' extracellular levels. Fluorescence immunohistochemistry and confocal microscopy, however, demonstrated that oxLDL-IC stimulated the release of HSP70B', which co-localized with cell-associated oxLDL-IC. In HSP70B'-green fluorescent protein-transfected mouse RAW 264.7 cells, oxLDL-IC-induced HSP70B' co-localized with membrane-associated oxLDL-IC as well as the lipid moiety of internalized oxLDL-IC. Furthermore, the data demonstrated that HSP70B' is involved in cell survival, and this effect could be mediated by sphingosine kinase 1 (SK1) activation. An examination of regularly implicated cytokines revealed a significant relationship between HSP70B' and the release of the anti-inflammatory cytokine interleukin-10 (IL-10). Small interfering RNA knockdown of HSP70B' resulted in a corresponding decrease in SK1 mRNA levels and SK1 phosphorylation as well as increased release of IL-10. In conclusion, these findings suggest that oxLDL-IC induce the synthesis and release of HSP70B', and once stimulated, HSP70B' binds to the cell-associated and internalized lipid moiety of oxLDL-IC. The data also implicate HSP70B' in key cellular functions, such as regulation of SK1 activity and release of IL-10, which influence macrophage activation and survival. PMID: 20348092 [PubMed - indexed for MEDLINE] | | |
| Local and regional mechanical characterisation of a collagen-glycosaminoglycan scaffold using high-resolution finite element analysis.
June 15, 2010 at 8:02 AM
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| | Local and regional mechanical characterisation of a collagen-glycosaminoglycan scaffold using high-resolution finite element analysis. J Mech Behav Biomed Mater. 2010 May;3(4):292-302 Authors: Stops AJ, Harrison NM, Haugh MG, O'Brien FJ, McHugh PE Artificial tissue growth requires cells to proliferate and differentiate within the host scaffold. As cell function is governed by mechano-sensitive selection, tissue type is influenced by the microscopic forces exposed to the cells, which is a product of macroscopically straining the scaffold. Accordingly, the microscopic strain environment within a CG scaffold is offered here. Using muCT to characterise CG scaffold architecture, two high-resolution 3D FE models were used to predict the deformation mechanics. While also providing an analysis of region-specific features, such as relative density, pore diameters and microstructural elastic stability, the deformation patterns afforded strains to be inferred for seeded cells. The results indicate a regional dependence, in terms of architectural and mechanical properties. Specifically, the peripheral regions demonstrated the lowest volume fraction, the highest stress concentrations and the greatest potential for elastic instability. Conversely, the mid-region exhibited the most homogeneous environment. Based on the proviso of mechano-sensitive proliferation and differentiation, the findings suggest cell function will vary between CG scaffold regions. Further work should investigate the possibility of improving the fabrication process in order to deliver a construct in line with the mid-region, or alternatively, isolation of the mid-region may prove beneficial for cell culturing. PMID: 20346897 [PubMed - indexed for MEDLINE] | | |
| In vitro proliferation and chondrogenic differentiation of rat bone marrow stem cells cultured with gelatin hydrogel microspheres for TGF-beta1 release.
June 15, 2010 at 8:02 AM
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| | In vitro proliferation and chondrogenic differentiation of rat bone marrow stem cells cultured with gelatin hydrogel microspheres for TGF-beta1 release. J Biomater Sci Polym Ed. 2010;21(5):609-21 Authors: Ogawa T, Akazawa T, Tabata Y The objective of this study was to evaluate the proliferation and chondrogenic differentiation of rat bone marrow-derived mesenchymal stem cells (MSCs) cultured with gelatin hydrogel microspheres of cell scaffold which can release transforming growth factor-beta1 (TGF-beta1). Gelatin was dehydrothermally cross-linked in different conditions in a water-in-oil emulsion state to obtain gelatin hydrogel microspheres with different water content. The microspheres functioned not only as the scaffold of MSC, but also the carrier matrix of TGF-beta1 release. The MSC proliferation depended on the water content of microspheres. Higher MSC proliferation was observed for the gelatin microspheres with lower water content. When cultured with the gelatin hydrogel microspheres, MSC formed their aggregates, in contrast to culturing with hydrogel sheets. The cell viability was significantly high compared with that of the hydrogel sheet. The production of sulfated glycosaminaglycan (sGAG) from MSC was examined as a measure of chondrogenic differentiation, after their culturing in a normal and chondrogenic differentiation media. For both the cultures, the amount of sGAG produced was significantly higher for MSC cultured with the gelatin microspheres than that of the gelatin sheet. Stronger differentiation of MSC was achieved in culture with the microspheres incorporating TGF-beta1 than that of MSC cultured in the medium containing the same amount of TGF-beta1. It is concluded that the gelatin hydrogel microspheres function well as both the scaffold of MSC and the matrix of TGF-beta1 release, resulting in enhanced MSC aggregation and the consequent promotion of cell proliferation and differentiation. PMID: 20338095 [PubMed - indexed for MEDLINE] | | |
| Novel use of X-ray micro computed tomography to image rat sciatic nerve and integration into scaffold.
June 15, 2010 at 8:02 AM
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| | Novel use of X-ray micro computed tomography to image rat sciatic nerve and integration into scaffold. J Neurosci Methods. 2010 Apr 30;188(1):39-44 Authors: Watling CP, Lago N, Benmerah S, FitzGerald JJ, Tarte E, McMahon S, Lacour SP, Cameron RE This paper describes how specimens of nervous tissue can be prepared for successful imaging in X-ray Micro Computed Tomography (microCT), and how this method can be used to study the integration of nervous tissue into a polymeric scaffold. The sample preparation involves staining the biological tissue with osmium tetroxide to increase its X-ray attenuation, and a technique for maintaining the specimen in a moist environment during the experiment to prevent drying and shrinkage. Using this method it was possible to observe individual nerve fascicles and their relationship to the 3-D tissue structure. A scaffold supporting a regenerated sciatic nerve was similarly stained to distinguish the nervous tissue from the scaffold, and to observe how the nerve grew through a 2.5 mm long, 100 microm x 100 microm cross-section channel polyimide array. Furthermore, blood vessels could be identified in these images, and it was possible to monitor how a large proximal blood vessel split through the channel scaffold and proceeded down individual channels. This paper explains how microCT is a useful tool both for studying the location and extent of growth into a polymeric scaffold, and for determining whether the regenerated tissue has blood supply. PMID: 20138083 [PubMed - indexed for MEDLINE] | | |
| Porcine induced pluripotent stem cells may bridge the gap between mouse and human iPS.
June 15, 2010 at 8:02 AM
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| | Porcine induced pluripotent stem cells may bridge the gap between mouse and human iPS. IUBMB Life. 2010 Apr;62(4):277-82 Authors: Esteban MA, Peng M, Deli Z, Cai J, Yang J, Xu J, Lai L, Pei D Recently, three independent laboratories reported the generation of induced pluripotent stem cells (iPSCs) from pig (Sus scrofa). This finding sums to the growing list of species (mouse, human, monkey, and rat, in this order) for which successful reprogramming using exogenous factors has been achieved, and multiple others are possibly forthcoming. But apart from demonstrating the universality of the network identified by Shinya Yamanaka, what makes the porcine model so special? On one side, pigs are an agricultural commodity and have an easy and affordable maintenance compared with nonhuman primates that normally need to be imported. On the other side, resemblance (for example, size of organs) of porcine and human physiology is striking and because pigs are a regular source of food the ethical concerns that still remain in monkeys are not applicable. Besides, the prolonged lifespan of pigs compared with other domestic species can allow exhaustive follow up of side effects after transplantation. Porcine iPSCs may thus fill the gap between the mouse model, which due to its ease is preferred for mechanistic studies, and the first clinical trials using iPSCs in humans. However, although these studies are relevant and have created significant interest they face analogous problems that we discuss herein together with potential new directions. PMID: 20101630 [PubMed - indexed for MEDLINE] | | |
| Development of a high-specificity enzyme-linked immunosorbent assay (ELISA) system for the quantification and validation of intact rat osteocalcin.
June 15, 2010 at 8:02 AM
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| | Development of a high-specificity enzyme-linked immunosorbent assay (ELISA) system for the quantification and validation of intact rat osteocalcin. Immunol Invest. 2010;39(1):54-73 Authors: Funaoka H, Dohi Y, Ohgushi H, Akahane M, Imamura T Osteocalcin (OC) exhibits hard tissue-specific expression and binding activity to hydroxyapatite. Therefore, measurement of secreted OC is a very useful index for evaluating osteoblastic differentiation in regenerative bone. In the present study, we established a high-specificity sandwich enzyme-linked immunosorbent assay (ELISA) system for the quantification of intact rat OC, which could be useful for validating tissue-engineered bone samples nondestructively and continuously. The range of detection with the sandwich ELISA system was 0.1-100 ng OC/mL of cell culture media or rat sera. No cross-reactivities were detected with OCs from other species, including human, bovine and mouse OCs, and other mammalian sera, which would contain the corresponding endogenous OCs. The intra- and inter-assay coefficients of variation were < or =4.9% and </=5.9%, respectively. Recovery tests only showed variation between 89.4% and 103.7%. Using the newly developed direct sandwich ELISA system, we found that the secreted OC levels from rat bone marrow-derived mesenchymal stem cells during osteogenic differentiation with dexamethasone were significantly higher than those from cells undergoing non-osteogenic or adipogenic differentiation. It was established that this ELISA system would be suitable for quantitative assessment of bone formation by cultured cells with or without scaffolds in rat experimental models. PMID: 20064085 [PubMed - indexed for MEDLINE] | | |
| The role of a human hematopoietic mesenchymal progenitor in wound healing and fibrotic diseases and implications for therapy.
June 15, 2010 at 8:02 AM
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| | The role of a human hematopoietic mesenchymal progenitor in wound healing and fibrotic diseases and implications for therapy. Curr Stem Cell Res Ther. 2009 Dec;4(4):266-80 Authors: Mattoli S, Bellini A, Schmidt M The human peripheral blood contains a multipotent precursor that shows hematopoietic stem cell features and transiently expresses markers of the myeloid lineage. Under permissive conditions, this precursor gives rise to committed progenitors of various lineages, including a mesenchymal progenitor cell known by the name of fibrocyte. The fibrocytes still express some hematopoietic and myeloid antigens together with fibroblast markers. They constitutively release pro-fibrotic and angiogenic factors and can modulate ongoing inflammatory reactions through the release of a number of chemokines. Under appropriate stimulation, fibrocytes produce increased amounts of extracellular matrix components and acquire a contractile phenotype similar to that of activated fibroblasts (myofibroblasts). Fibrocytes synthesizing new collagen or acquiring myofibroblast markers have been detected in pulmonary diseases characterized by an extensive remodeling of the bronchial wall or progressive fibrosis, in the skin of patients affected by nephrogenic systemic fibrosis, in human hypertrophic scars, in proliferative vitreoretinopathies and atherosclerotic lesions. Similar cells also participate in the stromal reaction to tumor development. Prevention of detrimental tissue remodeling in fibrotic diseases may be achieved by inhibiting the accumulation of fibrocytes. In-vitro expanded fibrocytes may be used to improve ineffective tissue repair or may be engineered for the delivery of gene constructs in anti-cancer therapy. PMID: 19500063 [PubMed - indexed for MEDLINE] | | |
| The future as I see it.
June 15, 2010 at 8:02 AM
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| | The future as I see it. J Am Coll Dent. 2009;76(4):17-20 Authors: Raum R Predicting the future is always chancy, but when a young practitioner begins a career in dentistry, it is worthwhile to have some well-reasoned expectations. The critical dimensions in the next several decades in dentistry will include technology, marketing, and society. PMID: 20415125 [PubMed - indexed for MEDLINE] | | | | 
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