| CIRM Panel Approves $300,000 Economic Study; Public Access to Data Still a Question
October 6, 2009 at 7:07 pm
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| | A subcommittee of the directors of the California stem cell agency today unanimously approved a $300,000 economic impact study of the agency's work by a firm that is expected to "execute a vibrant and aggressive strategy" supporting CIRM.Still up in the air is whether CIRM will allow other researchers and interested parties access to the basic data that will be gathered for the study at taxpayer |
| High-sensitivity bone marrow aspiration technology enhances leukemia cell detection
October 6, 2009 at 2:15 pm
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| More Locations for Economic Impact Meeting
October 6, 2009 at 12:12 pm
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| | If you are eager to participate in this morning's CIRM meeting involving a $300,000 economic impact study, the stem cell agency has added several new teleconference locations, including Des Moines.Here is the latest list of locations for the 11 a.m. PDT session in addition to Des Moines: San Francisco (2), Palo Alto, Los Angeles (2), UC Davis and Irvine,Specific addresses can be found on the |
| Research Reveals Unique Properties of Vitro's Fluorescent Stem Cells
October 6, 2009 at 11:12 am
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| MDC scientists show how hematopoietic stem cell development is regulated
October 6, 2009 at 10:12 am
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| NeoStem, Inc. Awarded NIH Research and Research Infrastructure 'Grand Opportunities' Grant
October 6, 2009 at 9:11 am
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| Cryo-Cell International's Stem Cell Research and Development Helps the Fight Against Breast Cancer
October 6, 2009 at 9:11 am
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| The Queensland Facility for Advanced Bioinformatics Selects IPA in Multi-Year Deal for Systems Biology Effort
October 6, 2009 at 7:11 am
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| Regulating assisted reproduction in Italy: a 5-year assessment.
October 6, 2009 at 6:37 am
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| | Regulating assisted reproduction in Italy: a 5-year assessment. Hum Fertil (Camb). 2009 Jun;12(2):81-8 Authors: Boggio A, Corbellini G In 2004, the Italian parliament comprehensively regulated medically assisted reproduction. Law 40/2004 has outlawed several techniques and tightly compressed the freedom of research in the area of human reproduction and regenerative medicine. This article analyses the post-2004 political, bioethical and legal debate on assisted reproduction in Italy. The analysis is grounded on empirical evidence on fertilisation outcomes released in 2007 and 2008 by the Italian government, on recent amendments related to the regulation of preimplantation genetic diagnosis and on the debates on the status of spare embryos as for their availability for scientific researches. The analysis shows that Law 40/2004 has failed to improve the access of infertile couples to assisted reproduction techniques and keeps supporting practices that the other jurisdictions have rejected because they are unwise from a clinical standpoint. Moreover, Law 40/2004 created severe limitations to scientific researches in the fields of medical embryology, gynaecology and regenerative medicine. With the political support of some Italian political parties and the Catholic Church, Law 40/2004 disregards the expectations of the majority of Italian citizens, international guidelines of good clinical practice, international codes of medical ethics, the interests of infertile couples and the social and economic relevance of biomedical research. PMID: 19802958 [PubMed - in process] |
| Developments and Challenges in Human Embryonic Stem Cell Research in Spain.
October 6, 2009 at 6:37 am
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| | Developments and Challenges in Human Embryonic Stem Cell Research in Spain. Stem Cell Rev Rep. 2009 Oct 3; Authors: Cervera RP, Stojkovic M After years of following the trail of others, Spain is finally making a serious bid in science, specifically in regenerative medicine. In the framework of the European Union, Spain is setting up the basis for a solid collaborative network between public and private institutions, involving basic, translational, applied, technological and clinical researchers. In a society characterised by the idiom "slow but secure", it is still too soon to see the results of the huge economic and infrastructure investment made. We present here an overview of the challenges that have been surmounted and the ones that will have to be solved in order to situate Spain as a reference country in regenerative medicine worldwide. PMID: 19802529 [PubMed - as supplied by publisher] |
| History of cord blood transplantation.
October 6, 2009 at 6:37 am
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| | History of cord blood transplantation. Bone Marrow Transplant. 2009 Oct 5; Authors: Gluckman E Since the first human cord blood transplant, performed 20 years ago, cord blood banks have been established worldwide for the collection and cryopreservation of cord blood for allogeneic hematopoietic stem cell transplant. A global network of cord blood banks and transplant centers has been established for a common inventory and study of clinical outcomes. Results of unrelated allogeneic cord blood transplants in malignant and nonmalignant diseases, in adults and children, show that, compared with HLA-matched unrelated BM transplant, cord blood has several advantages, including prompt availability of the transplant, decrease of GVHD and better long-term immune recovery resulting in a similar long-term survival. Several studies have shown that the number of cells is the most important factor for engraftment, although some degree of HLA mismatches is acceptable. Developments are expected to facilitate engraftment, including ex vivo expansion of stem cells, intrabone injection of cord blood cells and double cord blood transplants. In addition to hematopoietic stem cells, cord blood and placenta contain a large number of nonhematopoietic stem cells. In the absence of ethical concern, the unlimited supply of cells explains the increasing interest of using cord blood for developing regenerative medicine.Bone Marrow Transplantation advance online publication, 5 October 2009; doi:10.1038/bmt.2009.280. PMID: 19802032 [PubMed - as supplied by publisher] |
| Immediate Exposure to TNF-alpha Activate Dendritic Cells Derived from Non-Purified Cord Blood Mononuclear Cells.
October 6, 2009 at 6:37 am
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| | Immediate Exposure to TNF-alpha Activate Dendritic Cells Derived from Non-Purified Cord Blood Mononuclear Cells. Iran J Immunol. 2009 Sep;6(3):107-18 Authors: Ebrahimi M, Hassan ZM, Hadjati J, Hayat P, Moazzeni SM Background: Tumor necrosis factor alpha (TNF-alpha) is a primary mediator of immune regulation and might be required in the early stages of DC development from CD34+ cells. However, details of optimal timing of exposure to TNF-alpha in DC development process in monocytes or non-purified hematopoitic cells are still lacking and clear benefits of this approach to the development of DCs remain to be validated. Objective: To evaluate the effect of early and late exposure to TNF-alpha on DC development from non-purified cord blood mononuclear cells. Methods: To define the effects of early exposure to TNF-alpha on cord blood mononuclear cells, we cultured UCB-MNC in the presence of SCF, Flt3L, GM-CSF and IL-4 for 14 days and matured them for an extra 4 days. TNF-alpha was added on day 0, 7 and 14 in TNF-alpha + group, and only on day 14 in TNF-alpha - group where it was used only as a maturation factor. Results: Immediate exposure to TNF-alpha was shown to: (1) enhance the survival of cells in the first week of culture; (2) produce mature DCs with higher maturation markers (CD80, CD83, CD86 and HLA-DR); and (3) increase secretion of IL-12 by mature DCs. In contrast, delayed exposure to TNF-alpha stimulate mature DCs with less purity producing a high level of IL-10 and a low level of IL-12. Conclusion: We developed a simple, easy and cost effective method to generate DCs from non-fractionating mononuclear cells in this study. Also we confirm the presence of a large number of functional DCs under inflammatory conditions, where local concentrations of TNF-alpha were high. PMID: 19801784 [PubMed - in process] |
| Genome integrity: linking pluripotency and tumorgenicity.
October 6, 2009 at 6:37 am
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| | Genome integrity: linking pluripotency and tumorgenicity. Trends Genet. 2009 Oct 2; Authors: Deng W, Xu Y Genome integrity is a fundamental issue in both cancer and stem cell biology. A series of recent studies revealed that a tumor suppressor p53, which is required for genome integrity, is critical also for stem cell pluripotency and reprogramming, further strengthening the fundamental link between cancer and pluripotency. p53 and other tumor suppressors might be barriers to reprogramming somatic cells for the generation of induced pluripotent stem cells (iPSCs), and simultaneously and systematically destroying these barriers would improve reprogramming efficiency. Therefore, it is also crucial to determine the tumorgenicity of the cells derived from iPSCs for any future therapeutic use. PMID: 19801173 [PubMed - as supplied by publisher] |
| Stem cells for stress urinary incontinence: the adipose promise.
October 6, 2009 at 6:08 am
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| | Stem cells for stress urinary incontinence: the adipose promise. J Cell Mol Med. 2009 Oct 3; Authors: Roche R, Festy F, Fritel X Abstract Stress urinary incontinence (SUI), the most common type of incontinence in women, is a frequent and costly ailment responsible for an alteration to the quality of life. While medical treatment give some rather deceiving results, surgical techniques that include colposuspension or tension-free vaginal tape, employed in cases of urethral support defect, give a 5 year cure rate of more than 80%. However, these techniques could lead to complications or recurrence of symptoms. Recently, the initiation of urethral cell therapy has been undertaken by doctors and researchers. One principal source of autologous adult stem cells is generally used: muscle precursor cells (MPCs) which are the progenitors of skeletal muscle cells. Recently, a few research groups have shown interest in the MPCs and their potential for the treatment of urinary incontinence. However, using MPCs or fibroblasts isolated from a striated muscle biopsy could be questionable on several point. One of them is the in vitro cultivation of cells, which raises issues over the potential cost of the technique. Besides, numerous studies have shown the multipotent or even the pluripotent nature of stromal vascular cells (SVF) or adipose-derived stem cells (ASCs) from adipose tissue. These cells are capable of acquiring in vitro many different phenotypes. Furthermore, recent animal studies have highlighted the potential interest of SVF cells or ASCs in cell therapy, in particular for mesodermal tissue repair and revascularization. Moreover, the potential interest of SVF cells or ASCs for the treatment of urinary incontinence in women is supported by many other characteristics of these cells that are discussed here. Since access to these cells via lipoaspiration is simple, and due to the fact that they are found in very large numbers in adipose tissue, their future potential as a stem cell reservoir for use urethral or other types of cell therapy is enormous. PMID: 19799652 [PubMed - as supplied by publisher] |
| 3-Tesla magnetic resonance angiographic assessment of a tissue-engineered small-caliber vascular graft implanted in a rat.
October 6, 2009 at 6:03 am
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| | 3-Tesla magnetic resonance angiographic assessment of a tissue-engineered small-caliber vascular graft implanted in a rat. J Biomed Mater Res B Appl Biomater. 2009 Oct 2; Authors: Yamanami M, Yamamoto A, Iida H, Watanabe T, Kanda K, Yaku H, Nakayama Y In the development of small-caliber vascular grafts (diameter; less than 3 mm), animal implantation studies have been mostly performed by using rat abdominal aortas, and their certain patency must evaluate with sacrificing every observation periods, which is both labor-intensive and time-consuming when performing a large number of experiments. This study is the first to demonstrate the application of 3-Tesla contrast-free time-of-flight magnetic resonance angiography (TOF-MRA) in the continuous assessment of the status of a tissue-engineered vascular graft in rat. As a model graft, a single connective tubular tissue (diameter; 1.5 mm), prepared by embedding the silicone rod (diameter; 1.5 mm) into a subcutaneous pouch of a rat for 2 weeks an in vivo tissue-engineering, was used. The graft was implanted in the abdominal aorta (diameter; 1.3 mm) of the rat by end-to-end anastomosis. Repeated TOF-MRA imaging of the graft obtained over a 3-month follow-up period after implantation made it possible to evaluate the patency of the graft, both simply and noninvasively. It also permitted visualization of the connected abdominal aorta and renal and common iliac arteries having smaller caliber (diameter; less than 1 mm). In addition, the degree of the stenosis or aneurysm could also be detected. 3-Tesla MRA allowed the simplified and noninvasive assessment of the status on the vascular graft, including the formation of a stenosis or aneurysm, in the same rat at different times, which will be contributing to enhance the development of tissue-engineered vascular grafts even with small caliber. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009. PMID: 19802838 [PubMed - as supplied by publisher] |
| Collagen II/hyaluronan/chondroitin-6-sulfate tri-copolymer scaffold for nucleus pulposus tissue engineering.
October 6, 2009 at 6:03 am
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| | Collagen II/hyaluronan/chondroitin-6-sulfate tri-copolymer scaffold for nucleus pulposus tissue engineering. J Biomed Mater Res B Appl Biomater. 2009 Oct 2; Authors: Huang B, Li CQ, Zhou Y, Luo G, Zhang CZ This study aims to investigate the bioactivity of collagen II/hyaluronan/chondroitin-6-sulfate tri-copolymer as bionic scaffold for nucleus pulposus (NP) tissue engineering. Collagen II (C II) (pH 1-2) was mixed with hyaluronan (HyA) and lyophilized to prepare C II/HyA matrices. Chondroitin 6-sulfate (6-CS) was covalently attached to the C II/HyA matrices using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Then, cells were expanded from rabbit NP and seeded in the tri-copolymer scaffold. Cell-scaffold hybrids were maintained for up to 28 days in culture. Cell viability/proliferation, extracellular matrix (ECM)-related gene expression, and the content of sulfated glycosaminoglycans (s-GAG) were evaluated. Our results are as following: when cultured for 28 days, the cell-scaffold hybrids maintained active cell viability/proliferation and exhibited a significantly increased s-GAG content. In addition, rabbit NP cells cultured in the scaffold demonstrated a significantly higher level of C II and aggrecan gene expression and a significantly lower level of Collagen I (C I) gene expression when compared with that of monolayer cells. Histological studies and scanning electron microscopy (SEM) further indicated newly secreted ECM deposits in the scaffolds. In conclusion, the C II/HyA-CS scaffold may be an alternative material for NP tissue engineering due to its satisfactory bioactivity, and it deserves further in vivo investigation. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009. PMID: 19802835 [PubMed - as supplied by publisher] |
| Development of novel chitin/nanosilver composite scaffolds for wound dressing applications.
October 6, 2009 at 6:03 am
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| | Development of novel chitin/nanosilver composite scaffolds for wound dressing applications. J Mater Sci Mater Med. 2009 Oct 3; Authors: Madhumathi K, Sudheesh Kumar PT, Abhilash S, Sreeja V, Tamura H, Manzoor K, Nair SV, Jayakumar R Antibiotic resistance of microorganisms is one of the major problems faced in the field of wound care and management resulting in complications like infection and delayed wound healing. Currently a lot of research is focused on developing newer antimicrobials to treat wounds infected with antibiotic resistant microorganisms. Silver has been used as an antimicrobial agent for a long time in the form of metallic silver and silver sulfadiazine ointments. Recently silver nanoparticles have come up as a potent antimicrobial agent and are finding diverse medical applications ranging from silver based dressings to silver coated medical devices. Chitin is a natural biopolymer with properties like biocompatibility and biodegradability. It is widely used as a scaffold for tissue engineering applications. In this work, we developed and characterized novel chitin/nanosilver composite scaffolds for wound healing applications. The antibacterial, blood clotting and cytotoxicity of the prepared composite scaffolds were also studied. These chitin/nanosilver composite scaffolds were found to be bactericidal against S. aureus and E. coli and good blood clotting ability. These results suggested that these chitin/nanosilver composite scaffolds could be used for wound healing applications. PMID: 19802687 [PubMed - as supplied by publisher] |
| Atelocollagen-associated autologous chondrocyte implantation for the repair of chondral defects of the knee: a prospective multicenter clinical trial in Japan.
October 6, 2009 at 6:03 am
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| | Atelocollagen-associated autologous chondrocyte implantation for the repair of chondral defects of the knee: a prospective multicenter clinical trial in Japan. J Orthop Sci. 2009 Sep;14(5):579-88 Authors: Tohyama H, Yasuda K, Minami A, Majima T, Iwasaki N, Muneta T, Sekiya I, Yagishita K, Takahashi S, Kurokouchi K, Uchio Y, Iwasa J, Deie M, Adachi N, Sugawara K, Ochi M BACKGROUND: New tissue-engineering technology was developed to create a cartilage-like tissue in a three-dimensional culture using atelocollagen gel. The minimum 2-year followup outcome of transplanting autologous chondrocytes cultured in atelocollagen gel for the treatment of full-thickness defects of cartilage in knees was reported from the single institution. The present multicenter study was conducted to determine clinical and arthroscopic outcomes in patients who underwent atelocollagen-associated autologous chondrocyte implantation for the repair of chondral defects of the knees. METHODS: At six medical institutes in Japan, we prospectively evaluated the clinical and arthroscopic outcomes of transplanting autologous chondrocytes cultured in atelocollagen gel for the treatment of full-thickness defects of cartilage in 27 patients (27 knees) with cartilage lesions on a femoral condyle or on a patellar facet over 24 months. RESULTS: The Lysholm score significantly increased from 60.0 +/- 13.7 points to 89.8 +/- 9.5 points (P = 0.001). Concerning the ICRS grade for arthroscopic appearance, 6 knees (24%) were assessed as grade I (normal) and 17 knees (68%) as grade II (nearly normal). There were few adverse features, except for detachment of the graft in two cases. CONCLUSIONS: We concluded that transplanting chondrocytes in a newly formed matrix of atelocollagen gel can promote restoration of the articular cartilage of the knee. PMID: 19802670 [PubMed - in process] |
| [Chondrocytes - one cell type, different subpopulations : Characteristics and behavior of different types of chondrocytes and implications for tissue engineering applications.]
October 6, 2009 at 6:03 am
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| | [Chondrocytes - one cell type, different subpopulations : Characteristics and behavior of different types of chondrocytes and implications for tissue engineering applications.] Orthopade. 2009 Oct 4; Authors: Grad S, Salzmann GM Chondrocytes represent the most important cell source for engineering of cartilaginous tissues. Depending on the tissue type and the localization within the tissue, these cells may behave differently. Numerous studies have been done to compare articular, nasal, auricular, and costal chondrocytes in order to evaluate differences between knee and ankle joint cartilage and to investigate topographical variations within an articular joint. Moreover, the zonal structure of articular cartilage needs to be considered because it leads to phenotypical differences between chondrocytes of the superficial and the deeper zones. Several studies indicate, however, that even differentiated chondrocytes demonstrate a certain plasticity and strive to adapt their phenotypes to a new mechanical and biochemical environment. The aim of this review is to report on similarities and differences of chondrocytes from different tissues, zones, and topographical locations. In particular, an overview of recent results from comparative studies is presented, and possible consequences for the design of tissue engineering models are discussed. PMID: 19802604 [PubMed - as supplied by publisher] |
| DNA damaging bystander signalling from stem cells, cancer cells and fibroblasts after Cr (VI) exposure and its dependence on telomerase.
October 6, 2009 at 6:03 am
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| | DNA damaging bystander signalling from stem cells, cancer cells and fibroblasts after Cr (VI) exposure and its dependence on telomerase. Mutat Res. 2009 Oct 1; Authors: Cogan N, Baird DM, Phillips R, Crompton L, Caldwell M, Rubio MA, Newson R, Lyng F, Case CP The bystander effect is a feature of low dose radiation exposure and is characterized by a signaling process from irradiated cells to non irradiated cells, which causes DNA and chromosome damage in these 'nearest neighbour' cells. Here we show that a low and short dose of Cr(VI) can induce stem cells, cancer cells and fibroblasts to chronically secrete bystander signals, which cause DNA damage in neighboring cells. The Cr(VI) induced bystander signaling depended on the telomerase status of either cell. Telomerase negative fibroblasts were able to receive DNA damaging signals from telomerase positive or negative fibroblasts or telomerase positive cancer cells. However telomerase positive fibroblasts were resistant to signals from Cr(VI) exposed telomerase positive fibroblasts or cancer cells. Stem cells, with positive Oct4 staining as a marker of pluripotency, showed no significant increase of DNA damage from adjacent Cr and mitomycin C exposed fibroblasts whilst those cells that were negatively stained did. This selectivity of DNA damaging bystander signaling could be an important consideration in developing therapies against cancer and in the safety and effectiveness of tissue engineering and transplantation using stem cells. PMID: 19800897 [PubMed - as supplied by publisher] |
| Porous bioactive diopside (CaMgSi(2)O(6)) ceramic microspheres for drug delivery.
October 6, 2009 at 6:03 am
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| | Porous bioactive diopside (CaMgSi(2)O(6)) ceramic microspheres for drug delivery. Acta Biomater. 2009 Sep 30; Authors: Wu C, Zreiqat H Ideal bioceramic microspheres for bone regeneration need to be bioactive, degradable and at the same time posses a controlled drug release ability. The main disadvantage of the currently available microspheres is their failure to combine these properties. The aim of this study is to develop bioactive ceramic microspheres with optimal properties for use in bone tissue regeneration. In this study, we utilize diopside (CaMgSi(2)O(6), DP) with proven excellent bioactivity and degradation ability to develop microspheres by controlling their porosity, size and further modify their surface with polymer to enhance and control their drug loading/release ability. The phase composition, surface and inner microstructure, and porosity of DP microspheres were tested. Results indicate that carbon powders as porogens with various contents determined the porosity of the porous DP microspheres. The drug loading and release ability of Dexamethazone (DEX) from porous DP microspheres was regulated by their porosity and size. Poly (lactide-co-glycolide) (PLGA) modification forms a film on the surface of DP microspheres and resulted in an enhanced DEX loading and release ability of the microspheres. Results presented here indicate that the developed DP microspheres have the potential to be used as bioactive filling materials for bone tissue regeneration. PMID: 19800428 [PubMed - as supplied by publisher] |
| Characterisation of carbon nanotube (MWCNT) containing P(3HB)/bioactive glass composites for tissue engineering applications.
October 6, 2009 at 6:03 am
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| | Characterisation of carbon nanotube (MWCNT) containing P(3HB)/bioactive glass composites for tissue engineering applications. Acta Biomater. 2009 Sep 30; Authors: Misra SK, Ohashi F, Valappil SP, Knowles JC, Roy I, Silva SR, Salih V, Boccaccini AR Poly(3-hydroxybutyrate)(P(3HB)) composites with bioactive glass particles and multiwall carbon nanotubes (MWCNT) were prepared and used to identify whether the electrical properties of MWCNT can be used to detect the bioactivity of P(3HB)/bioactive glass composites. The presence of MWCNT (2-7 wt%) increased the surface roughness of the composites. The presence of MWCNT in low quantity enhanced MG-63 osteoblast-like cell attachment and proliferation compared to composites with higher concentration of MWCNT. Current-voltage measurements demonstrated that the electrical resistance of the composites containing bioactive glass particles decreased over a 45 day immersion period in SBF, whereas composites without bioactive glass showed no significant change over the same period. PMID: 19800427 [PubMed - as supplied by publisher] |
| Reactive calcium phosphate - containing poly (ester-co-ether) methacrylate bone adhesives: chemical, mechanical and biological considerations.
October 6, 2009 at 6:03 am
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| | Reactive calcium phosphate - containing poly (ester-co-ether) methacrylate bone adhesives: chemical, mechanical and biological considerations. Acta Biomater. 2009 Sep 30; Authors: Zhao X, Olsen I, Li H, Gellynck K, Buxton PG, Knowles JC, Salihl V, Young AM A poly (propylene glycol -co- lactide) dimethacrylate adhesive with monocalcium phosphate monohydrate (MCPM) / beta - tricalcium phosphate (beta -TCP) fillers in various levels have been investigated. Water sorption by the photo-polymerized materials catalyzed varying filler conversion to dicalcium phosphate (DCP). Polymer modulus was found to be enhanced upon raising total calcium phosphate content. With greater DCP levels faster release of phosphate and calcium ions and improved buffering of polymer degradation products was observed. This could reduce the likelihood of pH-catalyzed bulk degradation and localized acid production and thereby may prevent adverse biological responses. Bone-like MG-63 cells were found to attach, spread and have normal morphology on both the polymer and composite surfaces. Moreover, composites implanted into chick embryo femurs became closely apposed to the host tissue and did not appear to induce adverse immunological reaction. The above results suggest that the new composite materials hold promise as clinical effective bone adhesives. PMID: 19800424 [PubMed - as supplied by publisher] |
| Biodegradation, biodistribution and toxicity of chitosan.
October 6, 2009 at 6:03 am
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| | Biodegradation, biodistribution and toxicity of chitosan. Adv Drug Deliv Rev. 2009 Sep 30; Authors: Kean T, Thanou M Chitosan is a natural polysaccharide that has attracted significant scientific interest during the last two decades. It is a potentially biologically compatible material that is chemically versatile (-NH(2) groups and various M(w)). These two basic properties have been used by drug delivery and tissue engineering scientists to create a plethora of formulations and scaffolds that show promise in healthcare. Despite the high number of published studies, chitosan is not approved by the FDA for any product in drug delivery, and as a consequence very few biotech companies are using this material. This review will aim to provide information on these biological properties that affect chitosan's safe use in drug delivery. The term "Chitosan" represents a large group of structurally different chemical entities that may show different biodistribution, biodegradation and toxicological profiles. Here we aim to review research in this area and critically discuss chitosan's potential to be used as a generally regarded as safe (GRAS) material. PMID: 19800377 [PubMed - as supplied by publisher] |
| A biodegradable porous composite scaffold of PGA/beta-TCP for bone tissue engineering.
October 6, 2009 at 6:03 am
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| | A biodegradable porous composite scaffold of PGA/beta-TCP for bone tissue engineering. Bone. 2009 Sep 29; Authors: Cao H, Kuboyama N Polyglycolic acid (PGA) and beta-tricalcium phosphate (beta-TCP) each have many applications as tissue repair materials. In this study, three-dimensional (3D) porous composite scaffolds of PGA/beta-TCP (in 1:1 and 1:3 weight ratios) were fabricated using the solvent casting and particulate leaching method. PGA/beta-TCP scaffolds with high porosity, interconnected 3D pores and rough surfaces were obtained and were observed using scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). The PGA/beta-TCP scaffolds were investigated during the repair of critical bone defects (3 mm diameter, 2 mm depth) in rat femoral medial-epicondyles, compared with hydroxylapatite (HAP) and no implant as controls. Quantitative imageology analysis (volume and density of new bone) and qualitative histological evaluations (haematoxylin and eosin staining; tartrate-resistant acid phosphatase-haematoxylin counterstaining) were characterized using in vivo micro-CT images and histological sections at 0, 14, 30 and 90 days after surgery. Significant differences of all variables were tested by multivariate analysis (p < 0.05). The results showed that the bone reformation by using the PGA/beta-TCP scaffolds began within 14 days of surgery, and were healing well at 30 days after surgery. By 90 days after surgery, the bone replacement was almost completed and presented a healthy bone appearance. The new bone mineral densities (mg/cm(3)) with HAP, PGA/beta-TCP (1:1) and PGA/beta-TCP (1:3) at 90 days after surgery were: 390.4 +/- 18.1, 563.8 +/- 26.9 and 606.3 +/- 26.9, respectively. The new bone mineral density with the PGA/beta-TCP scaffold was higher than with HAP (p < 0.001), and with the PGA/beta-TCP (1:3) scaffold was higher than with the PGA/beta-TCP (1:1) scaffold at each time examined (p < 0.05). The biodegradation percents (%) of HAP, PGA/beta-TCP (1:1) and PGA/beta-TCP (1:3) at 90 days after surgery were: 35.1 +/- 5.5, 99.0 +/- 1.0 and 96.2 +/- 3.3, respectively. The biodegradation percents of the PGA/beta-TCP scaffolds were higher than HAP at each time examined (p < 0.01), and matched the osteogenesis rates. The PGA/beta-TCP scaffolds were almost replaced by new growing bone within 90 days after surgery. Thus the PGA/beta-TCP composite scaffold, especially weight ratio 1:3, exhibited a strong ability for osteogenesis, mineralization and biodegradation for bone replacement. PMID: 19800045 [PubMed - as supplied by publisher] |
| In vivo biological responses and bioresorption of tilapia scale collagen as a potential biomaterial.
October 6, 2009 at 6:03 am
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| | In vivo biological responses and bioresorption of tilapia scale collagen as a potential biomaterial. J Biomater Sci Polym Ed. 2009;20(10):1353-68 Authors: Sugiura H, Yunoki S, Kondo E, Ikoma T, Tanaka J, Yasuda K To date, collagen for biomedical uses has been obtained from mammalian sources. The purpose of this study was to evaluate the in vivo biological responses and bioresorption of collagen obtained from tilapia (Oreochromis niloticas) scales as compared to those of collagen from porcine dermis. Collagen sponges with micro-porous structures were fabricated from reconstituted collagen fibrils using freeze-drying and cross-linked by dehydrothermal treatment (DHT treatment) or additional treatment with a water-soluble carbodiimide (WSC treatment). The mechanical properties of the tilapia collagen sponges were similar to those of porcine collagen sponges with the same cross-linking methods, where WSC treatment remarkably improved the properties over DHT treatment alone. The pellet implantation tests into the paravertebral muscle of rabbits demonstrated that tilapia collagen caused rare inflammatory responses at 1- and 4-week implantations, statistically similar to those of porcine collagen and a high-density polyethylene as a negative control. The bioresorption rates of both the collagen implants were similar, except for the DHT-treated tilapia collagen sponges at 1-week implantation. These results suggest that tilapia collagen is a potential alternative to conventional mammalian collagens in biomedical uses. PMID: 19622276 [PubMed - indexed for MEDLINE] |
| Cardiac myocytes derived from murine reprogrammed fibroblasts: intact hormonal regulation, cardiac ion channel expression and development of contractility.
October 6, 2009 at 6:03 am
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| | Cardiac myocytes derived from murine reprogrammed fibroblasts: intact hormonal regulation, cardiac ion channel expression and development of contractility. Cell Physiol Biochem. 2009;24(1-2):73-86 Authors: Pfannkuche K, Liang H, Hannes T, Xi J, Fatima A, Nguemo F, Matzkies M, Wernig M, Jaenisch R, Pillekamp F, Halbach M, Schunkert H, Sarić T, Hescheler J, Reppel M AIMS: Induced pluripotent stem (iPS) cells have a developmental potential similar to that of blastocyst-derived embryonic stem (ES) cells and may serve as an autologous source of cells for tissue repair, in vitro disease modelling and toxicity assays. Here we aimed at generating iPS cell-derived cardiomyocytes (CMs) and comparing their molecular and functional characteristics with CMs derived from native murine ES cells. METHODS AND RESULTS: Beating cardiomyocytes were generated using a mass culture system from murine N10 and O9 iPS cells as well as R1 and D3 ES cells. Transcripts of the mesoderm specification factor T-brachyury and non-atrial cardiac specific genes were expressed in differentiating iPS EBs. Using immunocytochemistry to determine the expression and intracellular organisation of cardiac specific structural proteins we demonstrate strong similarity between iPS-CMs and ES-CMs. In line with a previous study electrophysiological analyses showed that hormonal response to beta-adrenergic and muscarinic receptor stimulation was intact. Action potential (AP) recordings suggested that most iPS-CMs measured up to day 23 of differentiation are of ventricular-like type. Application of lidocaine, Cs+, SEA0400 and verapamil+ nifedipine to plated iPS-EBs during multi-electrode array (MEA) measurements of extracellular field potentials and intracellular sharp electrode recordings of APs revealed the presence of I(Na), I(f), I(NCX), and I(CaL), respectively, and suggested their involvement in cardiac pacemaking, with I(CaL) being of major importance. Furthermore, iPS-CMs developed and conferred force to avitalized ventricular tissue that was responsive to beta-adrenergic stimulation. CONCLUSIONS: Our data demonstrate that the cardiogenic potential of iPS cells is comparable to that of ES cells and that iPS-CMs possess all fundamental functional elements of a typical cardiac cell, including spontaneous beating, hormonal regulation, cardiac ion channel expression and contractility. Therefore, iPS-CMs can be regarded as a potentially valuable source of cells for in vitro studies and cellular cardiomyoplasty. PMID: 19590195 [PubMed - indexed for MEDLINE] | | | 
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