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| Stem Cell Agency Seeking Legislative Removal of 50-person Staff Cap
April 30, 2010 at 12:43 PM
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| Directors of the California stem cell agency yesterday decided to work with a state legislator on a proposal that would give CIRM much needed relief from an ill-considered limit that caps the agency's staff at 50.
Previously CIRM was moving towards an effort to kill the legislation, at least for the next year or so, because of other provisions it found less than agreeable.
The cap on CIRM | | |
| Scanty Coverage of CIRM's $28 Million in Grants
April 30, 2010 at 10:13 AM
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| The announcement yesterday that the California stem cell agency had given away $28 million for research attracted extremely modest attention in the mainstream media.
Our automated searches turned up only two brief items today: one in the San Francisco Business Times and one on the Orange County Register Internet site. Both focused primarily on the grants in their local areas.
The light | | |
| A teratocarcinoma-like human embryonic stem cell (hESC) line and four hESC lines reveal potentially oncogenic genomic changes.
April 30, 2010 at 7:27 AM
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| | A teratocarcinoma-like human embryonic stem cell (hESC) line and four hESC lines reveal potentially oncogenic genomic changes. PLoS One. 2010;5(4):e10263 Authors: Hovatta O, Jaconi M, Töhönen V, Béna F, Gimelli S, Bosman A, Holm F, Wyder S, Zdobnov EM, Irion O, Andrews PW, Antonarakis SE, Zucchelli M, Kere J, Feki A The first Swiss human embryonic stem cell (hESC) line, CH-ES1, has shown features of a malignant cell line. It originated from the only single blastomere that survived cryopreservation of an embryo, and it more closely resembles teratocarcinoma lines than other hESC lines with respect to its abnormal karyotype and its formation of invasive tumors when injected into SCID mice. The aim of this study was to characterize the molecular basis of the oncogenicity of CH-ES1 cells, we looked for abnormal chromosomal copy number (by array Comparative Genomic Hybridization, aCGH) and single nucleotide polymorphisms (SNPs). To see how unique these changes were, we compared these results to data collected from the 2102Ep teratocarcinoma line and four hESC lines (H1, HS293, HS401 and SIVF-02) which displayed normal G-banding result. We identified genomic gains and losses in CH-ES1, including gains in areas containing several oncogenes. These features are similar to those observ! ed in teratocarcinomas, and this explains the high malignancy. The CH-ES1 line was trisomic for chromosomes 1, 9, 12, 17, 19, 20 and X. Also the karyotypically (based on G-banding) normal hESC lines were also found to have several genomic changes that involved genes with known roles in cancer. The largest changes were found in the H1 line at passage number 56, when large 5 Mb duplications in chromosomes 1q32.2 and 22q12.2 were detected, but the losses and gains were seen already at passage 22. These changes found in the other lines highlight the importance of assessing the acquisition of genetic changes by hESCs before their use in regenerative medicine applications. They also point to the possibility that the acquisition of genetic changes by ESCs in culture may be used to explore certain aspects of the mechanisms regulating oncogenesis. PMID: 20428235 [PubMed - in process] | | |
| Extracellular Matrix and Growth Factors in Salivary Gland Development.
April 30, 2010 at 7:27 AM
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| | Extracellular Matrix and Growth Factors in Salivary Gland Development. Front Oral Biol. 2010;14:48-77 Authors: Sequeira SJ, Larsen M, Devine T The interstitial extracellular matrix (ECM) and epithelial-cell associated basement membrane (BM) play critical roles in the morphogenesis and differentiation of developing salivary glands. Early studies used ex vivo organ culture and tissue recombination methods to identify the importance of the ECM in organ development. Incorporation of transgenic mice and molecular tools has facilitated progress in our understanding of the mechanisms by which ECM proteins influence SMG development. Recent work has identified alterations in the ECM, BM, and associated proteins in salivary gland diseases, including Sjögren's syndrome and salivary gland cancers, but the significance of such changes is not known. Understanding the basic mechanisms controlling morphogenesis and differentiation in mammalian organ development is the first step towards understanding pathogenesis. Molecular characterization of the function of the ECM and BM in cellular processes is critical for futur! e development of therapeutic approaches in regenerative medicine and tissue engineering. Here we provide a historical overview of experiments defining the functions of the ECM, ECM receptors, and associated molecules in salivary gland development. We include a discussion of the function of ECM-associated proteases and major growth factor signaling components that are in some way regulated by the ECM or associated molecules. We conclude with a discussion of defects in ECM and BM occurring in salivary gland pathologies and speculation on future areas of research pertaining to further understanding of the function of the ECM in the salivary gland. PMID: 20428011 [PubMed - as supplied by publisher] | | |
| The Changing Pattern of Acute Kidney Injury: From One to Multiple Organ Failure.
April 30, 2010 at 7:27 AM
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| | The Changing Pattern of Acute Kidney Injury: From One to Multiple Organ Failure. Contrib Nephrol. 2010;165:153-158 Authors: Okusa MD Acute kidney injury (AKI) is frequently encountered in the intensive care unit, and from its inception, morbidity and mortality increase in these patients compared to those without AKI. Despite numerous clinical trials and newer pharmacological agents, very little progress has been made to reduce the deaths that occur in this population. An important emerging concept is that AKI does not occur in isolation and it frequently involves other organs. Clinical conditions such as shock, trauma, and sepsis lead to an increase in fluid volume, cytokines/chemokines, uremic toxins and other soluble mediators that are known to affect distant organs. This critical loss of balance of these mediators appears to be due both to a reduction in clearance and increase in production as demonstrated by experimental studies of bilateral nephrectomy and ischemia-reperfusion, respectively. The evidence and mechanisms for distant organ injury following AKI will be discussed. PMID: 20427965 [PubMed - as supplied by publisher] | | |
| Wnt proteins promote bone regeneration.
April 30, 2010 at 7:27 AM
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| | Wnt proteins promote bone regeneration. Sci Transl Med. 2010 Apr 28;2(29):29ra30 Authors: Minear S, Leucht P, Jiang J, Liu B, Zeng A, Fuerer C, Nusse R, Helms JA The Wnt signaling pathway plays a central role in bone development and homeostasis. In most cases, Wnt ligands promote bone growth, which has led to speculation that Wnt factors could be used to stimulate bone healing. We gained insights into the mechanism by which Wnt signaling regulates adult bone repair through the use of the mouse strain Axin2(LacZ/LacZ) in which the cellular response to Wnt is increased. We found that bone healing after injury is accelerated in Axin2(LacZ/LacZ) mice, a consequence of more robust proliferation and earlier differentiation of skeletal stem and progenitor cells. In parallel, we devised a biochemical strategy to increase the duration and strength of Wnt signaling at the sites of skeletal injury. Purified Wnt3a was packaged in liposomal vesicles and delivered to skeletal defects, where it stimulated the proliferation of skeletal progenitor cells and accelerated their differentiation into osteoblasts, cells responsible for bone grow! th. The end result was faster bone regeneration. Because Wnt signaling is conserved in mammalian tissue repair, this protein-based approach may have widespread applications in regenerative medicine. PMID: 20427820 [PubMed - in process] | | |
| CNS/PNS boundary transgression by central glia in the absence of Schwann cells or Krox20/Egr2 function.
April 30, 2010 at 7:27 AM
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| | CNS/PNS boundary transgression by central glia in the absence of Schwann cells or Krox20/Egr2 function. J Neurosci. 2010 Apr 28;30(17):5958-67 Authors: Coulpier F, Decker L, Funalot B, Vallat JM, Garcia-Bragado F, Charnay P, Topilko P CNS/PNS interfaces constitute cell boundaries, because they delimit territories with different neuronal and glial contents. Despite their potential interest in regenerative medicine, the mechanisms restricting oligodendrocytes and astrocytes to the CNS and Schwann cells to the PNS in mammals are not known. To investigate the involvement of peripheral glia and myelin in the maintenance of the CNS/PNS boundary, we have first made use of different mouse mutants. We show that depletion of Schwann cells and boundary cap cells or inactivation of Krox20/Egr2, a master regulatory gene for myelination in Schwann cells, results in transgression of the CNS/PNS boundary by astrocytes and oligodendrocytes and in myelination of nerve root axons by oligodendrocytes. In contrast, such migration does not occur with the Trembler(J) mutation, which prevents PNS myelination without affecting Krox20 expression. Altogether, these data suggest that maintenance of the CNS/PNS boundary re! quires a Krox20 function separable from myelination control. Finally, we have analyzed a human patient affected by a congenital amyelinating neuropathy, associated with the absence of the KROX20 protein in Schwann cells. In this case, the nerve roots were also invaded by oligodendrocytes and astrocytes. This indicates that transgression of the CNS/PNS boundary by central glia can occur in pathological situations in humans and suggests that the underlying mechanisms are common with the mouse. PMID: 20427655 [PubMed - in process] | | |
| Ex vivo cultured limbal epithelial transplantation. A clinical perspective.
April 30, 2010 at 7:27 AM
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| | Ex vivo cultured limbal epithelial transplantation. A clinical perspective. Ocul Surf. 2010 Apr;8(2):80-90 Authors: Shortt AJ, Tuft SJ, Daniels JT ABSTRACT The term ex vivo cultured limbal epithelial transplantation (CLET) refers to the process of culturing a sheet of human limbal epithelium in the laboratory and transplanting this sheet back onto the limbal stem cell-deficient cornea of the same patient or another recipient. This emerging technology represents one of the earliest successes in regenerative medicine. CLET is, at present, best suited to patients who have unilateral total limbal stem cell deficiency arising from chemical injury and who are suitable for autologous cell culture and transplantation. Although the results of allogeneic cell transplantation are encouraging and superior to conventional stem cell transplantation techniques, insufficient follow-up precludes conclusions regarding the long-term outcomes. Other tissues, such as oral mucosal epithelium, are emerging as viable alternative sources of cells, especially for patients with bilateral disease. PMID: 20427011 [PubMed - in process] | | |
| Extracellular Matrix and Growth Factors in Salivary Gland Development.
April 30, 2010 at 7:15 AM
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| | Extracellular Matrix and Growth Factors in Salivary Gland Development. Front Oral Biol. 2010;14:48-77 Authors: Sequeira SJ, Larsen M, Devine T The interstitial extracellular matrix (ECM) and epithelial-cell associated basement membrane (BM) play critical roles in the morphogenesis and differentiation of developing salivary glands. Early studies used ex vivo organ culture and tissue recombination methods to identify the importance of the ECM in organ development. Incorporation of transgenic mice and molecular tools has facilitated progress in our understanding of the mechanisms by which ECM proteins influence SMG development. Recent work has identified alterations in the ECM, BM, and associated proteins in salivary gland diseases, including Sjögren's syndrome and salivary gland cancers, but the significance of such changes is not known. Understanding the basic mechanisms controlling morphogenesis and differentiation in mammalian organ development is the first step towards understanding pathogenesis. Molecular characterization of the function of the ECM and BM in cellular processes is critical for futur! e development of therapeutic approaches in regenerative medicine and tissue engineering. Here we provide a historical overview of experiments defining the functions of the ECM, ECM receptors, and associated molecules in salivary gland development. We include a discussion of the function of ECM-associated proteases and major growth factor signaling components that are in some way regulated by the ECM or associated molecules. We conclude with a discussion of defects in ECM and BM occurring in salivary gland pathologies and speculation on future areas of research pertaining to further understanding of the function of the ECM in the salivary gland. PMID: 20428011 [PubMed - as supplied by publisher] | | |
| The Evolution of Thrombospondins and their Ligand-binding Activities.
April 30, 2010 at 7:15 AM
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| | The Evolution of Thrombospondins and their Ligand-binding Activities. Mol Biol Evol. 2010 Apr 28; Authors: Bentley AA, Adams JC The extracellular matrix is a complex, multi-protein network that has essential roles in tissue integrity and inter-cellular signaling in the metazoa. Thrombospondins are extracellular, calcium-binding glycoproteins that have biologically important roles in mammals in angiogenesis, vascular biology, connective tissues, immune response and synaptogenesis. The evolution of these complex functional properties is poorly understood. We report here on the evolution of thrombospondins and their ligand-binding capacities, from comparative genomics of species representing the major phyla of metazoa and experimental analyses of the oligomerization properties of non-canonical thrombospondins of basal deuterostomes. Monomeric, dimeric, trimeric and pentameric thrombospondins have arisen through separate evolutionary events involving gain, loss, or modification of a coiled-coil domain or distinct domains at the amino-terminus. The relative transience of monomeric forms under e! volution implicates a biological importance for multi-valency of the C-terminal region of thrombospondins. Most protostomes have a single thrombospondin gene encoding a pentameric thrombospondin. The pentameric form is also present in deuterostomes, and gene duplications at the origin of deuterostomes and gene loss and further gene duplication events in the vertebrate lineage gave rise to distinct forms and novel domain architectures. Parallel analysis of the major ligands of mammalian thrombospondins revealed that many binding activities are neo-functions representing either co-evolutionary innovations in the deuterostome lineage or neo-functions of ancient molecules such as CD36. Contrasting widely conserved capacities include binding to heparan glycosaminoglycans, fibrillar collagen or RGD-dependent integrins. These findings identify thrombospondins as fundamental components of the extracellular interaction systems of metazoa and thus impact understanding of the evolutio! n of extracellular matrix networks. The widely-conserved activ! ities of thrombospondins in binding to extracellular matrix components or PS2 clade integrins will be relevant to use of thrombospondins in synthetic extracellular matrices or tissue engineering. In contrast, the neofunctions of vertebrate thrombospondins likely include interactions suitable for therapeutic targeting without general disruption of extracellular matrix. PMID: 20427418 [PubMed - as supplied by publisher] | | |
| Induction and regulation of differentiation in neural stem cells on ultra-nanocrystalline diamond films.
April 30, 2010 at 7:15 AM
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| | Induction and regulation of differentiation in neural stem cells on ultra-nanocrystalline diamond films. Biomaterials. 2010 Apr 26; Authors: Chen YC, Lee DC, Tsai TY, Hsiao CY, Liu JW, Kao CY, Lin HK, Chen HC, Palathinkal TJ, Pong WF, Tai NH, Lin IN, Chiu IM The interaction of ultra-nanocrystalline diamond (UNCD) with neural stem cells (NSCs) has been studied in order to evaluate its potential as a biomaterial. Hydrogen-terminated UNCD (H-UNCD) films were compared with standard grade polystyrene in terms of their impact on the differentiation of NSCs. When NSCs were cultured on these substrates in medium supplemented with low concentration of serum and without any differentiating factors, H-UNCD films spontaneously induced neuronal differentiation on NSCs. By direct suppression of mitogen-activated protein kinase/extracellular signaling-regulated kinase1/2 (MAPK/Erk1/2) signaling pathway in NSCs using U0126, known to inhibit the activation of Erk1/2, we demonstrated that the enhancement of Erk1/2 pathway is one of the effects of H-UNCD-induced NSCs differentiation. Moreover, functional-blocking antibody directed against integrin beta1 subunit inhibited neuronal differentiation on H-UNCD films. This result demonstrated! the involvement of integrin beta1 in H-UNCD-mediated neuronal differentiation. Mechanistic studies revealed the cell adhesion to H-UNCD films associated with focal adhesion kinase (Fak) and initiated MAPK/Erk1/2 signaling. Our study demonstrated that H-UNCD films-mediated NSCs differentiation involves fibronectin-integrin beta1 and Fak-MAPK/Erk signaling pathways in the absence of differentiation factors. These observations raise the potential for the use of UNCD as a biomaterial for central nervous system transplantation and tissue engineering. PMID: 20427083 [PubMed - as supplied by publisher] | | |
| Baculovirus as a Gene Delivery Vector for Cartilage and Bone Tissue Engineering.
April 30, 2010 at 7:15 AM
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| | Baculovirus as a Gene Delivery Vector for Cartilage and Bone Tissue Engineering. Curr Gene Ther. 2010 Apr 29; Authors: Lin CY, Lu CH, Luo WY, Chang YH, Sung LY, Chiu HY, Hu YC Baculovirus is an effective vector for gene delivery into various mammalian cells, including chondrocytes and mesenchymal stem cells, and has been employed for diverse applications. By gene delivery and expression of the growth factor, recombinant baculovirus has been shown to modulate the differentiation state of the cells and stimulates the production of extracellular matrix and tissue formation, hence repairing the damaged cartilage and bone in vivo. This article reviews the studies pertaining to the applications of baculovirus-mediated gene delivery in cartilage and bone tissue engineering and discusses recent progress, future applications and potential hurdles. PMID: 20426760 [PubMed - as supplied by publisher] | | |
| Challenges with advanced therapy medicinal products and how to meet them.
April 30, 2010 at 7:15 AM
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| | Challenges with advanced therapy medicinal products and how to meet them. Nat Rev Drug Discov. 2010 Mar;9(3):195-201 Authors: , , Schneider CK, Salmikangas P, Jilma B, Flamion B, Todorova LR, Paphitou A, Haunerova I, Maimets T, Trouvin JH, Flory E, Tsiftsoglou A, Sarkadi B, Gudmundsson K, O'Donovan M, Migliaccio G, AncÄ ns J, Maciulaitis R, Robert JL, Samuel A, Ovelgönne JH, Hystad M, Fal AM, Lima BS, Moraru AS, Turcáni P, Zorec R, Ruiz S, Akerblom L, Narayanan G, Kent A, Bignami F, Dickson JG, Niederwieser D, Figuerola-Santos MA, Reischl IG, Beuneu C, Georgiev R, Vassiliou M, Pychova A, Clausen M, Methuen T, Lucas S, Schüssler-Lenz M, Kokkas V, Buzás Z, MacAleenan N, Galli MC, LinÄ" A, Gulbinovic J, Berchem G, Fraczek M, Menezes-Ferreira M, Vilceanu N, Hrubisko M, Marinko P, Timón M, Cheng W, Crosbie GA, Meade N, di Paola ML, VandenDriessche T, Ljungman P, D'Apote L, Oliver-Diaz O, Büttel I, Celis P Advanced therapy medicinal products (ATMPs), which include gene therapy medicinal products, somatic cell therapy medicinal products and tissue-engineered products, are at the cutting edge of innovation and offer a major hope for various diseases for which there are limited or no therapeutic options. They have therefore been subject to considerable interest and debate. Following the European regulation on ATMPs, a consolidated regulatory framework for these innovative medicines has recently been established. Central to this framework is the Committee for Advanced Therapies (CAT) at the European Medicines Agency (EMA), comprising a multidisciplinary scientific expert committee, representing all EU member states and European Free Trade Association countries, as well as patient and medical associations. In this article, the CAT discusses some of the typical issues raised by developers of ATMPs, and highlights the opportunities for such companies and research groups to! approach the EMA and the CAT as a regulatory advisor during development. PMID: 20190786 [PubMed - indexed for MEDLINE] | | |
| Endocultivation: does delayed application of BMP improve intramuscular heterotopic bone formation?
April 30, 2010 at 7:15 AM
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| | Endocultivation: does delayed application of BMP improve intramuscular heterotopic bone formation? J Craniomaxillofac Surg. 2010 Jan;38(1):54-9 Authors: Warnke PH, Bolte H, Schünemann K, Nitsche T, Sivananthan S, Sherry E, Douglas T, Wiltfang J, Becker ST INTRODUCTION: The time point of Bone morphogenetic protein (BMP) delivery on matrices in vivo may play an important role. Delayed application could be advantageous as this would allow soft tissue (ST) ingrowth and vascularisation of scaffolds prior to BMP-loading. The aim of this study was to compare the application of BMP injected simultaneously during matrix implantation with delayed application four weeks after matrix implantation for endocultivation in a rat model. MATERIAL AND METHODS: Bovine hydroxyapatite blocks were placed in pouches in the Musculus latissimus dorsi in 6 Lewis rats unilaterally to allow for soft tissue ingrowth. Four weeks later, a second block was inserted on the contralateral side of each rat. At that time point, 100microg rhBMP-2 in 2ml sodium chloride was injected on both sides to induce bone formation. For eight weeks, bone regeneration was monitored by computed tomography (CT) and fluorescent labelling. RESULTS: The simultaneous and ! delayed BMP application groups were significantly different (p=0.01). Slightly lower bone densities were seen for the delayed BMP application with a mean of 588 Hounsfield Units (HU) (standard deviation (SD) 30HU). Simultaneous BMP application revealed slightly higher densities with a mean of 633HU (SD 30HU). The largest differences were observed when comparing bone density directly after implantation or at the end of the observation period (p<0.0001). CONCLUSION: Bone density was slightly lower in the case of delayed application of BMP-2. The increase of bone density after application of BMP-2 was similar for both groups. Thus, delayed application of BMP had no advantageous effect in this particular study design. Further studies are needed to explore if varying delays, different material designs or special BMP application devices may alter these results. PMID: 19836963 [PubMed - indexed for MEDLINE] | | |
| Chondroitin sulphate (WF6 epitope) levels in peri-miniscrew implant crevicular fluid during orthodontic loading.
April 30, 2010 at 7:15 AM
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| | Chondroitin sulphate (WF6 epitope) levels in peri-miniscrew implant crevicular fluid during orthodontic loading. Eur J Orthod. 2010 Feb;32(1):60-5 Authors: Intachai I, Krisanaprakornkit S, Kongtawelert P, Ong-chai S, Buranastidporn B, Suzuki EY, Jotikasthira D The aim of this study was to monitor changes in chondroitin sulphate (CS; WF6 epitope) levels in peri-miniscrew implant crevicular fluid (PMICF) during orthodontic loading. Ten patients (seven males and three females; aged 22.0 +/- 3.4 years), who required orthodontic treatment with extraction of all four premolar teeth, participated in the study. Twenty miniscrew implants (used as orthodontic anchorage) were placed, two in each patient, buccally and bilaterally in the alveolar bone between the roots of the maxillary posterior teeth. Sentalloy closed-coil springs (50 g) were used to load the miniscrew implants and to move the maxillary canines distally. During the unloaded period, PMICF samples were collected on days 1, 3, 5, and 7 after miniscrew implant placement and on days 14, 21, 28, and 35 during the loaded period. Clinical mobility assessments of the miniscrew implants were recorded at each visit. The competitive enzyme-linked immunosorbent assay with monoc! lonal antibody WF6 was used to detect CS (WF6 epitope) levels in the PMICF samples. The differences between the CS (WF6 epitope) levels during the unloaded and loaded periods were determined by a Mann-Whitney U-test. During the loaded period, two miniscrew implants were considered to have failed. The CS (WF6 epitope) levels during the unloaded period ranged from 0.00 to 758.03 ng/ml and those during the loaded period from 0.00 to 1025.11 ng/ml. Medians of CS (WF6 epitope) levels, around 'immobile' miniscrew implants, between the unloaded and loaded periods were not significantly different (P = 0.07). CS (WF6 epitope) levels in PMICF can be detected and may be used as biomarkers for assessing alveolar bone remodelling around miniscrew implants during orthodontic loading. PMID: 19752017 [PubMed - indexed for MEDLINE] | | |
| Comparison of computed tomography and microradiography for graft evaluation after reconstruction of critical size bone defects using beta-tricalcium phosphate.
April 30, 2010 at 7:15 AM
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| | Comparison of computed tomography and microradiography for graft evaluation after reconstruction of critical size bone defects using beta-tricalcium phosphate. J Craniomaxillofac Surg. 2010 Jan;38(1):38-46 Authors: Nolff MC, Kokemueller H, Hauschild G, Fehr M, Bormann KH, Spalthoff S, Rohn K, Ruecker M, Gellrich NC INTRODUCTION: The aim of the study was to evaluate the accuracy of computed tomography (CT) for in vivo follow up after mandibular reconstruction. MATERIAL AND METHODS: Unilateral mandibular defects were surgically created in ten sheep and either reconstructed using blood soaked beta-tricalcium phosphate (beta-TCP) cylinders (group A, n=5) or blood soaked beta-TCP cylinders that were additionally loaded with autologous bone marrow (group B, n=5). The two graft designs resulted in different stages of graft ossification representative of different stages of healing. CT datasets were fused with microradiographs and measurements of ceramic area based on both methods were compared. RESULTS: Two animals (groups A (n=1) and B (n=1)) presented infection and graft dislocation that was visible on CT and were excluded from statistical evaluation. Group A grafts underwent moderate degradation (53.55%+/-9.7) and incomplete bony incorporation representing an intermediate state ! of healing while ceramic grafts within group B developed a high grade of osseointegration and degradation (94.2%+/-3.3) consistent with progressive healing. Statistical comparison of measurements based on both methods revealed a significant bias (p<0.05) and a non-significant variance for group A and a significant variance (p<0.05) and non-significant bias for group B. CONCLUSION: Our results indicate that conventional CT is not suitable to objectively evaluate ossification and degradation of a beta-TCP graft in vivo and further attempts to improve clinical visualization of beta-TCP need to be undertaken. PMID: 19700333 [PubMed - indexed for MEDLINE] | | |
| [Nacre-induced osteogenesis in the femoral condyles of New Zealand rabbits]
April 30, 2010 at 7:15 AM
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| | [Nacre-induced osteogenesis in the femoral condyles of New Zealand rabbits] Nan Fang Yi Ke Da Xue Xue Bao. 2009 Feb;29(2):220-3 Authors: Wang JJ, Chen JT, Zhang XR OBJECTIVE: To evaluate nacre powder-induced osteogensis in the femoral condyles of New Zealand rabbits and investigate the possible mechanism. METHODS: Nacre powder was implanted into the femoral condyles of New Zealand rabbits and 4, 8, and 12 weeks after the implantation, radiographic examinations were carried out and the bone density was evaluated. The bone tissue specimens were sliced after fixation for histological observations. The osteogenesis area on the slice was estimated with Ponceau Red staining 8 and 12 weeks after the implantation and calculated with Imaga-Pro software. RESULTS: X-ray after the operation did not reveal obvious evidence of angiogenesis in the femoral condyles, where the X-ray density underwent slight changes. The optical density decreased significantly after the implantation, and the quantity of the osteoid, woven and lamellar bone increased in the bone tissue with time. The osteogenesis area with Ponceau Red staining showed obvious b! one formation, which was significantly different from the control group. CONCLUSION: T Obvious osteogenesis occurred in the femoral condyles after nacre powder implantation in New Zealand rabbits. Nacre powder has slow biodegradation in vivo and induces osteogenesis by osteoinduction. PMID: 19246283 [PubMed - indexed for MEDLINE] | | |
| [Construction of an acellular porcine aortic valve]
April 30, 2010 at 7:15 AM
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| | [Construction of an acellular porcine aortic valve] Nan Fang Yi Ke Da Xue Xue Bao. 2009 Feb;29(2):209-12 Authors: Zhou HS, Gu CH, Chen WS, Zhao JC, Wang YY, Tan HM, Yi DH OBJECTIVE: To prepare a porcine aortic valve (PAV) free of the cellular components. METHODS: The cellular components of porcine PAV were completely removed using trypsin and Triton X-100, and the acellular PAV was examined microscopically with HE staining with its physical and chemical properties assessed. Transmission electron microscopy was used to observe the integrity of the collagen and elastin and the DNA contents in the PAV was detected to confirm the total removal of the cellular components. With the fresh PAV as the control, small pieces of the acellular PAV were implanted into the subcutaneous tissues of 4 rabbits, and 4 weeks after the implantation, the implants were harvested for microscopic observation. RESULTS: The cellular components were effectively removed from the cusps and roots of the PAV by trypsin and TritonX-100, with marked soluble protein loss [(0.24-/+0.04)% vs (0.48-/+0.12)%] and significantly increased water content [(92.2-/+1.5)% vs (8! 9.2-/+1.6)%]. The acellular PAV still maintained good fibrous scaffold structure and the shrinkage temperature and tension at fracture underwent no significantly changes [(67.9-/+1.0) degrees celsius; vs (68.8-/+0.8) degrees celsius; and (489.3-/+19.0) g/mm2 vs (540.7-/+19.5) g/mm2, respectively]. The PAVs implanted in rabbits showed only mild tissue reaction with a few infiltrating neutrophils, lymphocytes and plasmocytes observed 4 weeks later. The accelular PAV caused obviously milder inflammatory reactions than fresh PAV. CONCLUSIONS: The acellular PAV prepared by treatment with trypsin and Triton X-100 retains good fibrous scaffold structure and mechanical strength with low antigenicity. PMID: 19246280 [PubMed - indexed for MEDLINE] | | |
| [Urethral acellular matrix graft for repairing urethral defect in rabbits]
April 30, 2010 at 7:15 AM
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| | [Urethral acellular matrix graft for repairing urethral defect in rabbits] Nan Fang Yi Ke Da Xue Xue Bao. 2009 Jan;29(1):124-7, 132 Authors: Han P, Song C, Yang YR, Wei Q, Li H, Wang KJ OBJECTIVE: To assess the biocompatibility of a urethral acellular matrix graft (UAMG) and evaluate its effect in repairing urethral defect in rabbit models. METHODS: The UAMG was prepared and its structural features were observed using optical and electron microscopy. In vitro cultured rabbit bladder smooth muscle cells were seeded on UAMG and the cell proliferation was observed. The cytotoxicity of the aqueous extract of the UAMG against the cells was evaluated by MTT assay, and its biocompatibility was assessed by implanting the grafts subcutaneously on the back of the rabbits. In 24 male rabbits, a 2-cm urethral defect was induced and repaired with UAMG (experimental group, n=12) or left untreated (control group, n=12). In both groups, the rabbits were sacrificed 2, 4, 8 and 12 weeks after the operation for histological and immunohistochemical examination of the tissue regeneration. RESULTS: The UAMG had a reticular fibrous structure without cell residues. The ! bladder smooth muscle cells showed normal proliferation on UAMG with normal cell morphology. The rabbits receiving the implants showed no abnormal response, and the UAMGs gradually degraded in vivo with grade 0 or 1 cytotoxcity showing satisfactory cytocompatibility. In the experimental group, new urethral tissues that were histologically compatible with normal urethral tissues were regenerated in the defect area 12 weeks after UAMG implantation. CONCLUSION: As a tissue engineered scaffold material for urethral reconstruction, the UAMG possesses good biocompatibility and can induce the regeneration of urethral epithelial cells and smooth muscle cells. PMID: 19218131 [PubMed - indexed for MEDLINE] | | |
| [Interface shear stress between the artificial bones and injectable calcium phosphate glue: an experimental study in rabbits]
April 30, 2010 at 7:15 AM
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| | [Interface shear stress between the artificial bones and injectable calcium phosphate glue: an experimental study in rabbits] Nan Fang Yi Ke Da Xue Xue Bao. 2009 Jan;29(1):78-81 Authors: Zhao L, Li Q, Lin LJ, Zhang L, Liu CL, Ding C OBJECTIVE: To evaluate the effect of the composite bone material, fibrin glue (FG) combined with beta-tricalcium phosphate (beta-TCP)/monocalcium phosphate, in repairing bone defects and assess the feasibility of using this cement for artificial joint fixation. METHODS: Bone defects were induced in 16 normal adult New Zealand white rabbits at the bilateral femoral lateral condyles where an 8-mm-deep hole (4 mm in diameter) was drilled on each side. The composite FG/calcium phosphate cement (CPC) (solution: power volume ratio of 0.3:1) was injected on one side of the bone defects (experimental group) and pressurized for 10 minutes, and CPC was injected on the other side (control). The rabbits were sacrificed at 2, 4, 8 or 12 weeks after the operation for gross observation and biomechanical tests. RESULT: The composite material FG/CPC was more effective than CPC for bone defect repair, and biomechanical tests revealed significant differences between them (P<0.05)! . The shear stress of the artificial bone cement in the FG/CPC group was stronger than that in CPC group. CONCLUSION: The FG/CPC composite possesses good biocompatibility and osteoconductivity and may serve as an ideal material for repairing bone defects. PMID: 19218118 [PubMed - indexed for MEDLINE] | | | | 
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