| Regulating assisted reproduction in Italy: a 5-year assessment.
October 6, 2009 at 7:22 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] |
| 3-Tesla magnetic resonance angiographic assessment of a tissue-engineered small-caliber vascular graft implanted in a rat.
October 6, 2009 at 7:22 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 7:22 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 7:22 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 7:22 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 7:22 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] |
| Developments and Challenges in Human Embryonic Stem Cell Research in Spain.
October 6, 2009 at 7:22 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 7:22 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 7:22 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 7:22 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] |
| DNA damaging bystander signalling from stem cells, cancer cells and fibroblasts after Cr (VI) exposure and its dependence on telomerase.
October 6, 2009 at 7:22 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 7:22 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 7:22 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 7:22 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 7:22 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 7:22 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] |
| The influence of parathyroid hormone on the adult hematopoietic stem cell niche.
October 6, 2009 at 7:22 am
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| | The influence of parathyroid hormone on the adult hematopoietic stem cell niche. Curr Osteoporos Rep. 2009 Jul;7(2):53-7 Authors: Rashidi N, Adams GB Adult hematopoietic stem cells (HSCs) reside in the bone marrow in stable microenvironments known as the stem cell niche. One key component of the stem cell niche is cells of the osteoblastic lineage. Factors that are known to affect osteoblast activity, such as parathyroid hormone (PTH), have also been shown to affect the HSCs. Treatment of mice with PTH has led to beneficial effects on the HSC pool, which have led to clinical trials of PTH treatment to enhance HSC-based therapies. PMID: 19631029 [PubMed - indexed for MEDLINE] |
| In vivo biological responses and bioresorption of tilapia scale collagen as a potential biomaterial.
October 6, 2009 at 7:22 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 7:22 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] |
| Commercial development of cell-based therapeutics: strategic considerations along the drug to tissue spectrum.
October 6, 2009 at 7:22 am
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| | Commercial development of cell-based therapeutics: strategic considerations along the drug to tissue spectrum. Regen Med. 2009 Jul;4(4):601-11 Authors: Parenteau NL In cell-based therapy, the process defines the product and the biological interaction between implant and host determines the outcome. Developing the optimum combination of process, product and a clinically relevant effect has been a challenge, leaving many potential therapies stalled in early clinical studies. This special report discusses pivotal factors in the development of cell-based technologies, irrespective of where they fit on the spectrum from cell-based drug to tissue construct, and how we can ensure delivery of an effective product to the clinic and the marketplace. Epidermal cell-based therapies serve as an historical lesson. PMID: 19580408 [PubMed - indexed for MEDLINE] |
| Role of bioinspired polymers in determination of pluripotent stem cell fate.
October 6, 2009 at 7:22 am
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| | Role of bioinspired polymers in determination of pluripotent stem cell fate. Regen Med. 2009 Jul;4(4):561-78 Authors: Abraham S, Eroshenko N, Rao RR Human pluripotent stem cells, including embryonic and induced pluripotent stem cells, hold enormous potential for the treatment of many diseases, owing to their ability to generate cell types useful for therapeutic applications. Currently, many stem cell culture propagation and differentiation systems incorporate animal-derived components for promoting self-renewal and differentiation. However, use of these components is labor intensive, carries the risk of xenogeneic contamination and yields compromised experimental results that are difficult to duplicate. From a biomaterials perspective, the generation of an animal- and cell-free biomimetic microenvironment that provides the appropriate physical and chemical cues for stem cell self-renewal or differentiation into specialized cell types would be ideal. This review presents the use of natural and synthetic polymers that support propagation and differentiation of stem cells, in an attempt to obtain a clear understanding of the factors responsible for the determination of stem cell fate. PMID: 19580405 [PubMed - indexed for MEDLINE] |
| Bone marrow-derived mesenchymal stem cells in fibrin augment angiogenesis in the chronically infarcted myocardium.
October 6, 2009 at 7:22 am
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| | Bone marrow-derived mesenchymal stem cells in fibrin augment angiogenesis in the chronically infarcted myocardium. Regen Med. 2009 Jul;4(4):527-38 Authors: Huang NF, Lam A, Fang Q, Sievers RE, Li S, Lee RJ AIMS: Current efforts to treat myocardial infarction include the delivery of cells and matrix scaffolds. Bone marrow-derived mesenchymal stem cells (BM-MSCs) are multipotent stem cells that secrete angiogenic growth factors, and fibrin has been shown to be a biomaterial that provides structural support to cells and tissues. The objective of this study was to characterize the attachment and viability of BM-MSCs in fibrin in vitro, and then to assess the efficacy of treatment with BM-MSCs in fibrin for promoting neovascularization in the chronically infarcted myocardium. MATERIALS & METHODS: BM-MSCs were cultured in fibrin and assessed for cell attachment and viability by using immunofluorescence staining for actin filaments and Live/Dead((R)) viability assays, respectively. To determine the efficacy of BM-MSCs in fibrin in vivo, chronically infarcted rat hearts were treated with either cells, cells in fibrin, fibrin or saline (n = 9). After 5 weeks, the infarct scar tissues were assessed for neovascularization. RESULTS: BM-MSCs exhibited robust cell attachment and viability when cultured in fibrin in vitro. Furthermore, when injected together into the infarcted tissue, BM-MSCs in fibrin could enhance neovasculature formation by increasing capillary density, in comparison to treatment by cells or fibrin separately. Concomitant to significant improvement in capillary density was an increase in the levels of VEGF in the infarct scar. CONCLUSION: This study demonstrates the angiogenic potential of the combined delivery of BM-MSCs and fibrin, and highlights the advantage of stem cell-matrix approaches for myocardial repair. PMID: 19580402 [PubMed - indexed for MEDLINE] |
| Cellular transplants, 20 years later: the pharma initiative.
October 6, 2009 at 7:22 am
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| | Cellular transplants, 20 years later: the pharma initiative. Regen Med. 2009 Jul;4(4):485-7 Authors: Emerich DF, Vasconcellos A PMID: 19580397 [PubMed - indexed for MEDLINE] |
| Generation of immunogenic dendritic cells from human embryonic stem cells without serum and feeder cells.
October 6, 2009 at 7:22 am
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| | Generation of immunogenic dendritic cells from human embryonic stem cells without serum and feeder cells. Regen Med. 2009 Jul;4(4):513-26 Authors: Tseng SY, Nishimoto KP, Silk KM, Majumdar AS, Dawes GN, Waldmann H, Fairchild PJ, Lebkowski JS, Reddy A Aim: Dendritic cell (DC)-based vaccines have a potential utility for use in the treatment of malignancy. Human embryonic stem cells (hESCs) may provide a more cost-effective and reliable source of DCs for immunotherapy purposes, providing on-demand access for patients. Method: We developed a protocol to generate DCs from hESCs in vitro in the absence of serum and feeder cells. This protocol uses growth factors bone morphogenetic protein-4, granulocyte macrophage-colony stimulating factor (GM-CSF), stem cell factor and VEGF in serum-free media to generate hESC-derived monocytic cells. These cells are further differentiated to hESC-derived immature DCs with GM-CSF and IL-4, and matured to hESC-derived mature DCs with a maturation cocktail consisting of GM-CSF, TNF-alpha, IL-1beta, IFN-gamma and PGE2. Results: This study demonstrates the applicability of our defined differentiation process in generating functional hESC-derived DCs from multiple hESC lines. We show that hESC-derived immature DCs phagocytose, process, and present antigen upon maturation. hESC-derived mature DCs express the maturation marker CD83, produce Th1-directing cytokine IL-12p70, migrate in response to chemokine, and activate both viral and tumor antigen-specific T-cell responses. Conclusion: We developed a chemically defined system to generate unlimited numbers of DCs from hESCs. Our results demonstrate that hESC-derived DCs generated from this process are immunogenic and have the potential to be used for DC immunotherapy. PMID: 19580370 [PubMed - indexed for MEDLINE] |
| Human gingival fibroblasts release high-mobility group box-1 protein through active and passive pathways.
October 6, 2009 at 7:22 am
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| | Human gingival fibroblasts release high-mobility group box-1 protein through active and passive pathways. Oral Microbiol Immunol. 2009 Aug;24(4):292-8 Authors: Feghali K, Iwasaki K, Tanaka K, Komaki M, Machigashira M, Ishikawa I, Izumi Y INTRODUCTION: The nuclear protein high-mobility group box-1 (HMGB1) acts as a late mediator of inflammation when secreted in the extracellular milieu. In this study, we examined the effect of lipopolysaccharides from periodontal pathogens and apoptotic and necrotic cell death on HMGB1 production in human gingival fibroblasts (HGF). METHODS: HGF from healthy periodontal tissue were cultured and stimulated with lipopolysaccharides (LPS) from Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Escherichia coli. We also initiated apoptotic and necrotic cell deaths in HGF. The HMGB1 released in the supernatants from stimulated or dying cells was measured. Immunocytochemical staining against HMGB1 was performed in LPS-stimulated HGF. RESULTS: A significantly higher amount of HMGB1 was detected from necrotic and apoptotic HGF. LPS from A. actinomycetemcomitans, P. gingivalis, and E. coli significantly induced the production of HMGB1 in a time-dependent manner. After 6 h of LPS stimulation, HMGB1 was present in the cytoplasm of cells whereas its location was mainly nuclear after 24 h. CONCLUSIONS: LPS from two major periodontal pathogens, A. actinomycetemcomitans and P. gingivalis, induced HMGB1 secretion from HGF. Apoptotic and necrotic cell deaths resulted in the enhancement of HMGB1. Our results suggest that HGF can be a source of HMGB1 by both active secretion and passive release, and that HMGB1 from HGF may contribute to periodontal tissue destruction. PMID: 19572890 [PubMed - indexed for MEDLINE] |
| Porous biodegradable scaffold: predetermined porosity by dissolution of poly(ester-anhydride) fibers from polyester matrix.
October 6, 2009 at 7:22 am
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| | Porous biodegradable scaffold: predetermined porosity by dissolution of poly(ester-anhydride) fibers from polyester matrix. Macromol Biosci. 2009 Jul 7;9(7):654-60 Authors: Rich J, Korhonen H, Hakala R, Korventausta J, Elomaa L, Seppälä J A novel selective leaching method for the porogenization of the biodegradable scaffolds was developed. Continuous, predetermined pore structure was prepared by dissolving fast eroding poly(epsilon-caprolactone)-based poly(ester-anhydride) fibers from the photo-crosslinked poly(epsilon-caprolactone) matrix. The porogen fibers dissolved in the phosphate buffer (pH 7.4, 37 degrees C) within a week, resulting in the porosity that replicated exactly the single fiber dimensions and the overall arrangement of the fibers. The amount of the porosity, estimated with micro-CT, corresponded with the initial amount of the fibers. The potential to include bioactive agents in the porogen fibers was demonstrated with the bioactive glass. PMID: 19165824 [PubMed - indexed for MEDLINE] |
| [Effects of mechanical vibration on the morphology of the acellular scaffold for the spinal cord]
October 6, 2009 at 7:22 am
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| | [Effects of mechanical vibration on the morphology of the acellular scaffold for the spinal cord] Nan Fang Yi Ke Da Xue Xue Bao. 2008 Oct;28(10):1748-51 Authors: Yin WH, Jin DD, Deng XY, Lu KW OBJECTIVE:To investigate the effects of mechanical vibration on the morphology of the acellular scaffold for the spinal cord and establish a procedure to construct an acellular rat spinal cord allograft retaining intact matrix fibers for repairing spinal cord injuries. METHODS:Fifteen segments of rat spinal cord were divided randomly into 3 groups and subjected to mechanical vibration at the frequency 80 r/min (group A, n=5), 120 r/min (group B, n=5), and 160 r/min (group C, n=5) respectively. The spinal cord was treated with Triton X-100 and sodium deoxycholate at room temperature and washed with distilled water. The specimens were observed microscopically with HE staining, and the ultrastructure was observed using scanning electron microscope. RESULTS: In group A, the spinal cord specimens contained numerous cells and neural sheaths. Vibration at 120 and 160 r/min (in groups B and C) resulted in depletion of all the cells, axons and neural sheaths from the spinal cord after treatment with Triton X-100 and sodium deoxycholate. The acellular spinal cord consisted of a meshwork of the matrix fibers in longitudinal arrangement. In group C, however, obvious disruption of both the spinal dura mater and the matrix fiber occurred in the acellular spinal cord. CONCLUSION: All the cells, axons and neural sheaths in the spinal cord can be removed by chemical extraction with Triton X-100 and sodium deoxycholate. Mechanical vibration at suitable frequency may cell preserve the 3-dimensional structure of the matrix fibers. The acellular spinal cord scaffold may serve as an ideal material for constructing tissue-engineered spinal cord. PMID: 18971201 [PubMed - indexed for MEDLINE] |
| Surface modification of bioactive glasses and preparation of PDLLA/bioactive glass composite films.
October 6, 2009 at 7:22 am
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| | Surface modification of bioactive glasses and preparation of PDLLA/bioactive glass composite films. J Biomater Appl. 2009 Aug;24(2):119-38 Authors: Gao Y, Chang J In order to improve the homogeneous dispersion of particles in the polymeric matrix, 45S5, mesoporous 58S, and 58S bioactive glasses were surface modified by esterification reactions with dodecyl alcohol at reflux temperature of 260 degrees C (named as m-45S5, m-mesoporous 58S, and m-58S, respectively). The modified particles showed better hydrophobicity and longer time of suspension in organic matrix. The PDLLA/bioactive glass composite films were fabricated using surface modified bioactive glass particles through solvent casting-evaporation method. Surface morphology, mechanical property, and bioactivity were investigated. The results revealed that the inorganic particle distribution and tensile strength of the composite films with modified bioactive glass particles were significantly improved while great bioactive properties were maintained. Scanning electron microscopy (SEM) observation illustrated that the modified bioactive glass particles were homogeneously dispersed in the PDLLA matrix. The maximum tensile strengths of composite films with modified bioactive glass particles were higher than that of composite films with unmodified bioactive glass particles. The bioactivity of the composite films were evaluated by being soaked in the simulated body fluid (SBF) and the SEM observation of the films suggested that the modified composite films were still bioactive in that they could induce the formation of HAp on its surface and the distribution of HAp was even more homogeneous on the film. The results mentioned above indicated that the surface modification of bioactive glasses with dodecyl alcohol was an effective method to prepare PDLLA/bioactive glass composites with enhanced properties. By studying the comparisons of modification effects among the three types of bioactive glasses, we could get the conclusion that the size and morphology of the inorganic particles would greatly affect the modification effects and the properties of composites. PMID: 18801895 [PubMed - indexed for MEDLINE] |
| [A research on ectopic osteogenesis and vascularization of tissue engineered bone promoted by 1,25-(OH)2D3]
October 6, 2009 at 7:22 am
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| | [A research on ectopic osteogenesis and vascularization of tissue engineered bone promoted by 1,25-(OH)2D3] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2007 Oct;21(10):1142-6 Authors: Li T, Wang J, Yang H OBJECTIVE: To study the ectopic osteogenesis and vascularization of the tissue engineered bone promoted by an artificial bone composite that consists of coral hydroxyapatite (CHA), 1,25-(OH)2D3, human marrow stromal osteoblast (hMSO), and human umbilical vein endothelial cell (hUVEC). METHODS: After the isolation and the culture in vitro, hMSO and hUVEC were obtained. Then, hMSO (5 x 10(5)/ml) and hUVEC (2.5 x 10(5)/ml) were seeded at a ratio of 2 : 1 onto the CHA scaffolds coated with 1,25-(OH)2D3 (the experimental group) or onto the CHA scaffolds without 1,25-(OH)2D3 (the control group). The scaffolds were cultured in vitro for 3 days, and then the scaffolds were implanted into the pockets that had been made on the backs of 18 nude mice. Then, 6 of the mice were implanted with one experimental engineered bone bilaterally; another 6 mice were implanted with one control engineered bone bilaterally; the remaining 6 mice were implanted with one experimental engineered bone and one control engineered bone on each side. At 4, 8 and 12 weeks after operation, the retrieved scaffolds and cells were examined by the nake eye and histology as well as by the scanning electron microscopy. The quantitative assessment of the newly-formed bone and the quantitative analysis of the newly-formed blood vessels were performed. RESULTS: The evaluations by the histology revealed that at 4 weeks the original bone tissues grew into the scaffolds in all the groups, but significantly more newly-formed bone tissues and newly-formed blood vessels were found in the experimental group. At 12 weeks the newly-formed bone tissues were found in all the groups, but there was a typical bone unit found in the experimental group. There was a significantly smaller amount of capillary vessels in the control group than in the experimental group at all the time points. The evaluations by the scanning electron microscopy revealed that at 4 weeks in the experimental group there were great amounts of extracelluar matrix that embedded the cells, and plenty of capillary vessels were found on the surface of the implanted bone materials and some of them grew into the materials; however, in the control group there was a smaller amount of capillary vessels although much extracelluar matrix was still found there. At 8 weeks sarciniform osteoids were found on some of the implanted materials, with much extracelluar matrix and many newly-formed capillary vessels in the experimental group; however, in the control group there were fewer capillary vessels and lower degrees of the bone maturity. The quantitative assessment of the newly-formed bone showed that the new-formed bones were 3.1 +/- 0.52 in the experimental group but 2.30 +/- 0.59 in the control group at 8 weeks (P < 0.05), and 4.63 +/- 0.55 vs. 3.53 +/- 0.62 at 12 weeks. There was a significant difference at these two time points between the two groups (P < 0.05). The quantitative analysis of the newly-formed blood vessels showed that the vascular areas were 28.74% +/- 7.81% in the experimental group but 19.52% +/- 4.57% in the control group at 4 weeks (P < 0.05), and 24.66% +/- 7.38% vs. 17.84% +/- 5.22% at 12 weeks. There was a significant difference at these two time points between the two groups (P < 0.05). CONCLUSION: 1,25-(OH)2D3 as an active factor can increase the interaction between hMSO and hUVEC, and thus promote the ectopic osteogenesis and vascularization in the tissue engineered bone. PMID: 17990787 [PubMed - indexed for MEDLINE] |
| [Odontogenesis of Delta1 gene transfected human dental pulp stem cells]
October 6, 2009 at 7:22 am
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| | [Odontogenesis of Delta1 gene transfected human dental pulp stem cells] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2007 Oct;21(10):1133-6 Authors: He F, Yang Z, Tan Y OBJECTIVE: To investigate the heterotopic odontogenesis ability of Delta1 gene transfected human dental pulp stem cell (DPSC) and nano-hydroxyapatite/collagen (nHAC) composite scaffold. METHODS: The cultured human DPSC was transfected with Delta1-enhanced green fluorescent protein recombinant retrovirus supernatant,and was selected by puromycin to obtain the positive cell clone. The experimental group contained the Delta1 transfected DPSC; however, the control group did not contain the Delta1 transfected DPSC but contained DPSC transfected with vectors only. The cells were seeded into the nHAC carriers and were cultured in the odonto-inductive medium. The growth of the transduced cells in the carriers was observed by the fluorescent phase contrast microscope and the scanning electron microscope (SEM). The cell-carrier composites were subcutaneously transplanted into the Delta1 transfected 8 nude mice (female, 8 weeks old). Eight weeks after operation, the composites were taken out and tested with the histological and the immunohistological methods. RESULTS: Green fluorescence was observed in the cells in the experimental group, which were grown in the carriers by the fluorescent phase contrast microscope. Observed by SEM, great amounts of transduced DPSC were observed along the scaffold materials, even filling the porous structures of nHAC and secreting a lot of extracellular matrix. However, in the control group, much fewer cells were found in the carriers. All the 4 Delta1 transduced DPSC-nHAC composites produced dentin-like structures that lined the surfaces of some nHAC porous structures. The odontoblast-like cells extended the cytoplasmic processes into the dentinal matrix, which was interfaced with a pulp-like interstitial tissue infiltrated with the blood vessels. Dentin sialophosphoprotein was expressed in the odontoblast-like cells when immunohisochemistry was performed. The morphology of the control composite was a typical one of the fibrous connective tissue, and only a little dentin-like structure was found in 2 of the 8 control transplants. CONCLUSION: DPSC can be used as the recipient cell of the Delta1 gene for expression and secretion of the Delta1 protein. The composites of the transfected cells and nHAC can induce heterotopic odontogenesis, which indicates that Delta1 is a novel candidate for the gene enhanced dentin-pulp composite engineering. PMID: 17990785 [PubMed - indexed for MEDLINE] |
| [In vitro hypoxic culture of human marrow mesenchymal stem cells and their biological features in adults]
October 6, 2009 at 7:22 am
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| | [In vitro hypoxic culture of human marrow mesenchymal stem cells and their biological features in adults] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2007 Oct;21(10):1128-32 Authors: Wang Q, Yang S, Yang C OBJECTIVE: To establish a model of the human marrow mesenchymal stem cells (hMSCs) cultured under the hypoxic condition in adults and to investigate the biological features of MSCs under hypoxia. METHODS: The bone marrow was obtained by aspiration at the posterior superior iliac spine in 3 healthy adult subjects. hMSCs were isolated by the gradient centrifugation and were cultured in the DMEM-LG that contained 20% fetal bovine serum. The serial subcultivation was performed 10-14 days later. The second passage of the hMSCs were taken, and they were divided into the following 4 groups according to the oxygen concentrations and the medium types: the normoxic group (20% O2, DMEM-LG, Group A), the hypoxic group (1% O2, DMEM-LG, Group B), the normoxic osteoblast induction group (20% O2, conditioned medium, Group C), and the hypoxic osteoblast induction group (1% O2, conditioned medium, Group D). The biological features of the cultured hMSCs under hypoxia were assessed by the cell count, the MTT method, the colony forming unit-fibroblast, the real-time RT-PCR, and the alkaline phosphatase (ALP) activity, and the alizarin red staining. RESULTS: The hMSCs cultured in the Group B and Group D had a significantly higher proliferation rate than those in the Group A (P < 0.01), and the culture effect was not influenced by the medium type. The hMSCs in the Group B had a significantly higher level of the colony-forming unit capability than the hMSCs cultured in the Group A (P < 0.01). After the induction, hMSCs in the Group B had a decreased number of the osteoblasts than hMSCs in the Group C. The hMSCs in the Group D had a gradually-increased activity of ALP, which was significantly lower than that in the Group C (P < 0.01). The RT-PCR examination revealed that ALP, osteocalcin, and mRNA expressions of collagen type I and osteonectin in the Group C significantly increased (P < 0.01). By comparison among the 3 groups, after the 4-week culture the obvious calcium salt deposit and the red-stained calcium nodus could be observed. CONCLUSION: Hypoxia can promote the proliferation rate of hMSCs, enhance the colony-forming ability and inhibit the differentiation of the osteoblasts. PMID: 17990784 [PubMed - indexed for MEDLINE] |
| [Experimental study on repair of articular cartilage defects with homograft of marrow mesenchymal stem cells seeded onto poly-L-lactic acid/gelatin]
October 6, 2009 at 7:22 am
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| | [Experimental study on repair of articular cartilage defects with homograft of marrow mesenchymal stem cells seeded onto poly-L-lactic acid/gelatin] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2007 Jul;21(7):753-8 Authors: Wang M, Xia Y, Wang S OBJECTIVE: To investigate the effect of homograft of marrow mesenchymal stem cells (MSCs) seeded onto poly-L-lactic acid (PLLA)/gelatin on repair of articular cartilage defects. METHODS: The MSCs derived from 36 Qingzilan rabbits, aging 4 to 6 months and weighed 2.5-3.5 kg were cultured in vitro and seeded onto PLLA/gelatin. The MSCs/PLLA/gelatin composite was cultured and transplanted into full thickness defects on intercondylar fossa. Thirty-six healthy Qingzilan rabbits were made models of cartilage defects in the intercondylar fossa. These rabbits were divided into 3 groups according to the repair materials with 12 in each group: group A, MSCs and PLLA/gelatin complex (MSCs/PLLA/gelatin); group B, only PLLA/gelatin; and group C, nothing. At 4, 8 and 12 weeks after operation, the gross, histological and immunohistochemical observations were made, and grading scales were evaluated. RESULTS: At 12 weeks after transplantation, defect was repaired and the structures of the cartilage surface and normal cartilage was in integrity. The defects in group A were repaired by the hyline-like tissue and defects in groups B and C were repaired by the fibrous tissues. Immunohistochemical staining showed that cells in the zones of repaired tissues were larger in size, arranged columnedly, riched in collagen II matrix and integrated satisfactorily with native adjacent cartilages and subchondral bones in group A at 12 weeks postoperatively. In gross score, group A (2.75 +/- 0.89) was significantly better than group B (4.88 +/- 1.25) and group C (7.38 +/- 1.18) 12 weeks after operation, showing significant differences (P < 0.05); in histological score, group A (3.88 +/- 1.36) was better than group B (8.38 +/- 1.06) and group C (13.13 +/- 1.96), and group B was better than group C, showing significant differences (P < 0.05). CONCLUSION: Transplantation of mesenchymal stem cells seeded onto PLLA/gelatin is a promising way for the treatment of cartliage defects. PMID: 17694670 [PubMed - indexed for MEDLINE] |
| [Comparison of acellular bovine pericardium material with collagen membrane in guiding bone regeneration]
October 6, 2009 at 7:22 am
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| | [Comparison of acellular bovine pericardium material with collagen membrane in guiding bone regeneration] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2007 Jul;21(7):743-7 Authors: Wu H, Hu G OBJECTIVE: To compare the effect of guiding bone regeneration between 1-ethyl-3(3-diaminopropyol)-carbodiimide (EDAC)-crosslinked acellular bovine pericardium (ABP) and medical collagen membrane (CM). METHODS: Defects of 7 mm X 7 mm x 5 mm were created in both mandibles of 24 rabbits, which weighted 2.6-3.5 kg. One side defect was covered with EDAC-crosslinked ABP(EDAC-crosslinked ABP group), the other side defect with medical CM as control(CM group). The ability of bone defect repair and change of both membrane materials were evaluated by gross observation, histological study and computer graphic analysis in the 4th, 8th, 16th and 24th weeks after operation. RESULTS: The surface of bone defects was even, consistent with adjacent normal bone in EDAC-crosslinked ABP group, while that of bone defects was of no evenness in CM group in the 16th and the 24th weeks. The histological observation showed that bone trabecula formed in the EDAC-crosslinked ABP group and fibrous connective tissue was seen in CM group in the 16th and the 24th weeks. There were no significant differences in new bone percentage of bone defects between 2 groups in the 4th and the 8th weeks (P > 0.05). In the 16th week new bone percentage of bone defects was 81.99% +/- 3.92% in EDAC-crosslinked ABP group and 76.35% +/- 4.29% in CM group, showing significant difference (P < 0.05). The average percentage of absorption in EDAC-crosslinked ABP group was 16.57%, 27.94%, 65.61 and 85.72% in the 4th, 8th, 16th and 24th weeks respectively, while that in CM group was more than 50% in the 4th week and completely degraded at the end of 8 weeks. CONCLUSION: EDAC-crosslinked ABP has a better effect on guiding bone regeneration than CM in the repair of bone defects. PMID: 17694668 [PubMed - indexed for MEDLINE] |
| [Dynamic change of epidermal stem cells in the wound healing course of diabetic rats]
October 6, 2009 at 7:22 am
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| | [Dynamic change of epidermal stem cells in the wound healing course of diabetic rats] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2007 Jul;21(7):693-7 Authors: Tian X, Bai S, Tian W OBJECTIVE: To observe the epidermal width, the amount variation and distribution character of epidermal stem cells(ESCs) and the wound healing rate at different periods of diabetes mellitus(DM) rats after trauma, then to study the correlation of them. METHODS: Forty-eight Wistar rats were divided into DM group and normal control group randomly (n=24). The DM rats were induced by streptozocin (STZ) and then made chronic healing wound by special perforex. At the 3rd, 4th, 7th, 14th and 21st days after trauma, the healing rate was calculated, the wound edge and granulation tissue were obtained for haematoxylin-eosin (HE) staining and immunohistochemical staining of keratin 19 (K19) and beta1 integrin. Then the epidermal width, the area and the gradation value of positive unit (PU) were measured. RESULTS: At the 3rd, 7th, 14th and 21st days after trauma, the wound healing rates of normal rats were 24. 48% +/- 3.37%, 50.46% +/- 1.26%, 92.82% +/- 2.12% and 99.41% +/- 0.66% respectively, while those of DM rats were 2.43% +/- 1.02%, 40.59% +/- 1.65%, 80.77% +/- 3.57% and 85.40% +/- 0.94% respectively, showing significant differences (P < 0.01). Before trauma, there was no significant difference in the epidermal width between normal rats and DM rats (P > 0.05). However, at the 3rd, 7th, 14th and 21st days after trauma, the epidermal widths of normal rats were 26.43 +/- 3.21, 33.29 +/- 3.52, 31.53 +/- 3.35 and 26.01 +/- 3.19 microm respectively, while those of DM rats were 23.58 +/- 2.33, 31.02 +/- 3.38, 33.72 +/- 5.49 and 21.80 +/- 4.02 microm respectively, the epidermal widths in DM rats were significantly lower than those in normal rats (P < 0.01). The average PU value of K19 in normal rats were 91.68%, 93.14%, 72.27% and 70.31% respectively, while those in DM rats were 40.29%, 40.79%, 29.94% and 10.37% respectively. The average PU value of beta1 integrin in normal rats were 49.6%, 91.16, 77.13% and 57.17% respectively, while those in DM rats were 38.94%, 24.16%, 61.36% and 38.83%. The results indicated that the average PU values of K19 and beta1 integrin in DM rats were significantly lower than those in normal rats (P < 0.05). CONCLUSION: The amount and activity decrease of ESCs may be one of the important mechanisms of difficult recovering wounds of DM rats. PMID: 17694656 [PubMed - indexed for MEDLINE] |
| [Experimental study on umbilical vascular compliance and expression of antigen after removing endothelial cell]
October 6, 2009 at 7:22 am
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| | [Experimental study on umbilical vascular compliance and expression of antigen after removing endothelial cell] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2007 Jul;21(7):688-92 Authors: Li Z, Li Z, Yi X OBJECTIVE: To evaluate which is better method zymogen or low temperature frozen in removing vascular endothelial cell so as to lay a foundation for creating a kind of brace which is not to be rejected and the same as own blood vessel. METHODS: Fresh and not damaged umbilical blood vessel was collected from natural labour women, human umbilical blood vessel was remove carefully from normal foetus, then was put into disinfectant at 37 C for 24 hours. They were divided into 3 groups:normal group (NG), zymogen group (ZG) and low temperature frozen group (LG). ZG: 0.1% collagen II enzyme was added in umbilical blood vessel and closed the both sides and the vascular endothelial cell was removed in 37 C water. LG:Umbilical blood vessel was put into liquid nitrogen for 24 hours after frozened step by step, and then it was put into 37 C water for 30-60s and the vascular endothelial cells were washed away by normal saline. NG:Umbilical blood vessel was kept into 4 C Kerb's liquid. The bacteria were cultured in each group. The samples were stained by HE, elastic fiber and collagen fiber were observed by light and scanning electron microscope. The difference of compliance was compared. Human leukocyte antigen ABC (HLA-ABC) and HLA-DR were observed by immunohistochemical method and the expression of antigen of umbilical blood vessel was analysed. Results In LG, umbilical vascular endothelial cells were removed completely; artery showed vertical smooth muscle and vein showed elastic membrane. In ZG, umbilical vascular endothelial cells were removed completely after 20 minutes; artery showed vertical smooth muscle cells and vein showed lower endothelial layer. The vascular compliance in LG was higher than that in NG, and the latter was also higher than that in ZG, but showing no significant differences (P > 0.05). The compliance of umbilical vein was 2-3 times as much as that of umbilical artery. The expression of HLA-ABC and HLA-DR in LG and ZG were lower than that in NG, showing significant differences (P < 0.01). CONCLUSION: Low temperature frozen method and zymogen method (0.1% collagen II enzyme for 20 min) can remove vascular endothelial cells of human umbilical blood vessel completely. Low temperature frozen method was better than zymogen method. PMID: 17694655 [PubMed - indexed for MEDLINE] | | | 
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