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| Attitudes of some European dental undergraduate students to the placement of direct restorative materials in posterior teeth.
June 19, 2010 at 8:45 AM
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| | Attitudes of some European dental undergraduate students to the placement of direct restorative materials in posterior teeth. J Oral Rehabil. 2010 Jun 14; Authors: Lynch CD, Guillem SE, Nagrani B, Gilmour AS, Ericson D Summary The aim of this article was to report on the attitudes, opinions and confidences of final year dental students in three European schools towards the restoration of posterior teeth and in particular towards the use of amalgam and resin composite. One hundred and twenty-eight pre-piloted questionnaires were distributed to final year dental students in Cardiff, Dublin and Malmö. The questionnaire sought information relating to various opinions and attitudes towards the use of amalgam and resin composite in posterior teeth. Information was returned anonymously. Ninety-one completed questionnaires were returned (response rate = 71%; Cardiff: n = 40, Dublin: n = 24, Malmö: n = 27). Ninety-three per cent of Malmö students (n = 24), 67% of Dublin students (n = 16) and 60% of Cardiff students (n = 24) reported that they feel confident when placing posterior resin composites. One hundred per cent of Malmö students (n = 27), 75% of Cardiff students (n = 30) and 33% of Dublin students (n = 8) would prefer to have a resin composite rather than amalgam, placed in one of their own posterior teeth. Eighty-five per cent of Malmö students (n = 23), 30% of Cardiff students (n = 12) and 25% of Dublin students (n = 6) perceive amalgam as being harmful to the environment. For the restoration of a posterior tooth in a pregnant female, 44% of students (n = 40) would place a resin composite restoration, and 7% (n = 6) would place an amalgam restoration, while 32% (n = 29) would place a temporary restoration. Students at Malmö report that they place more posterior resin composites and have greater confidence at placing posterior resin composites than students at Cardiff or Dublin. There was confusion relating to the choice of restorative materials for pregnant females. Large variations in restorative strategies among graduates must be considered as dental professionals can practice in all countries within the European Union. PMID: 20557432 [PubMed - as supplied by publisher] | | |
| Hydrogels as a platform for stem cell delivery to the heart.
June 19, 2010 at 8:45 AM
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| | Hydrogels as a platform for stem cell delivery to the heart. Congest Heart Fail. 2010 May 1;16(3):132-5 Authors: Kurdi M, Chidiac R, Hoemann C, Zouein F, Zgheib C, Booz G Stem cell therapy offers great promise to repair the injured or failing heart. The outcomes of clinical trials to date, however, have shown that the actual benefit realized falls far short of the promise. A number of factors may explain why that is the case, but poor stem cell retention and engraftment in the hostile environment of the injured heart would seem to be a major factor. Improving stem cell retention and longevity once delivered would seem a logical means to enhance their reparative function. One way to accomplish this goal may be injectable hydrogels, which would serve to fix stem cells in place while providing a sheltering environment. Hydrogels also provide a means to allow for the paracrine factors produced by encapsulated stem cells to diffuse into the injured myocardium. Alternatively, hydrogels themselves can be used for the sustained delivery of reparative factors. Here the authors discuss chitosan-based hydrogels. Congest Heart Fail. 2010;16:132-135. (c) 2010 Wiley Periodicals, Inc. PMID: 20557335 [PubMed - in process] | | |
| Testing the critical size in calvarial bone defects: revisiting the concept of a critical-size defect.
June 19, 2010 at 8:45 AM
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| | Testing the critical size in calvarial bone defects: revisiting the concept of a critical-size defect. Plast Reconstr Surg. 2010 Jun;125(6):1685-92 Authors: Cooper GM, Mooney MP, Gosain AK, Campbell PG, Losee JE, Huard J BACKGROUND: There is a clinical need for bone replacement strategies because of the shortfalls endemic to autologous bone grafting, especially in the pediatric patient population. For the past 25 years, the animal model that has been used to test bone replacement strategies has been the calvarial critical-size defect, based on the initial size of the bone defect. This study was undertaken to test the concept of the critical size in several different models. A review of the theoretical and scientific bases for the critical-size defect was also undertaken. METHODS: Two different rodent species (including 28 adult mice and six adult rats) were used to assess bone healing by means of two-dimensional radiographic analysis after creating small bone defects using different surgical techniques. RESULTS: Defects in mice that were smaller than critical-size defects (1.8-mm diameter) were shown to heal a maximum of 50 percent 1 year postoperatively. Small defects (2.3-mm diameter) in the rat skull showed approximately 35 percent healing after 6 weeks. Neither the choice of rodent species nor the maintenance of the dura mater significantly affected calvarial bone healing. CONCLUSIONS: These results suggest that calvarial bone healing is not well described and much more data need to be collected. Also, after a review of the existing literature and a critique of the clinical applicability of the model, it is suggested that the use of the term "critical-size defect" be discontinued. PMID: 20517092 [PubMed - indexed for MEDLINE] | | |
| Towards stem cell replacement therapies for Parkinson's disease.
June 19, 2010 at 8:45 AM
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| | Towards stem cell replacement therapies for Parkinson's disease. Biochem Biophys Res Commun. 2010 May 21;396(1):152-6 Authors: Arenas E Current therapeutic approaches for Parkinson's disease (PD) provide symptomatic relief but none of them change the course of disease. There is therefore a clear need for regenerative and cell replacement therapies (CRT). However, CRT faces several important challenges. First, the main symptoms of PD result from the loss of midbrain dopamine (DA) neurons, but other cell types are also affected. Second, transplantation of human ventral midbrain tissue from aborted fetuses has lead to proof of principle that CRT may work, however, it has also pointed out to important patient-, surgery- and cell preparation-related variables, which need to be improved. Third, while some patients have developed dyskinesias and, with time, Lewy bodies in the grafted cells, other patients have experienced remarkable improvement and have been able to stop their medication. Is there a case for PD CRT today? What is the possible contribution of stem cells to CRT? In this review, I will discuss what we learned from clinical trials using fetal tissue grafts, recent progress in the development of human stem cell-derived-DA neurons for CRT, and some of the issues that need to be solved in order to develop stem cells as tools for PD CRT. PMID: 20494130 [PubMed - indexed for MEDLINE] | | |
| [Cultivated human hair follicle cells are capable of integrating to skin structure in vivo]
June 19, 2010 at 8:45 AM
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| | [Cultivated human hair follicle cells are capable of integrating to skin structure in vivo] Tsitologiia. 2010;52(3):219-24 Authors: Cheremnykh ES, Radiukhina NV, Rutkevich PN, Shevelev AIa, Vlasik TN, Voroteliak EA, Vasil'ev AV, Terskikh VV In the present study, human keratinocytes and dermal papilla cells were labeled to investigate their behaviour after intradermal transplantation. Cells were transduced by lentiviral vectors that bore marker gene encoding green fluorescent protein (copGFP) or red fluorescent protein (DsRed). A portion of transgene expressing cells was evaluated by flow cytometry. Genetic constructions that we used provided high level (> 95 %) of transduction of hair follicle cells. In vitro transduced cells were injected under the epidermis of human skin fragments, and these fragments were then transplanted under the skin of immunodeficient mice. Injected epidermal keratinocytes were found, mainly, in hair follicles and partially in a zone of interfollicular epidermis, while dermal papilla cells were found in papilla derma. The results of the present research show that the chosen genetic constructions obtained on a basis of human immunodeficiency lentivirs are capable of effective and stable transduction of human skin cells. Injected cells survived and were found in the corresponding structures of the skin. PMID: 20429299 [PubMed - indexed for MEDLINE] | | |
| Hemangioblastic derivatives from human induced pluripotent stem cells exhibit limited expansion and early senescence.
June 19, 2010 at 8:45 AM
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| | Hemangioblastic derivatives from human induced pluripotent stem cells exhibit limited expansion and early senescence. Stem Cells. 2010 Apr;28(4):704-12 Authors: Feng Q, Lu SJ, Klimanskaya I, Gomes I, Kim D, Chung Y, Honig GR, Kim KS, Lanza R Human induced pluripotent stem cells (hiPSC) have been shown to differentiate into a variety of replacement cell types. Detailed evaluation and comparison with their human embryonic stem cell (hESC) counterparts is critical for assessment of their therapeutic potential. Using established methods, we demonstrate here that hiPSCs are capable of generating hemangioblasts/blast cells (BCs), endothelial cells, and hematopoietic cells with phenotypic and morphologic characteristics similar to those derived from hESCs, but with a dramatic decreased efficiency. Furthermore, in distinct contrast with the hESC derivatives, functional differences were observed in BCs derived from hiPSCs, including significantly increased apoptosis, severely limited growth and expansion capability, and a substantially decreased hematopoietic colony-forming capability. After further differentiation into erythroid cells, >1,000-fold difference in expansion capability was observed in hiPSC-BCs versus hESC-BCs. Although endothelial cells derived from hiPSCs were capable of taking up acetylated low-density lipoprotein and forming capillary-vascular-like structures on Matrigel, these cells also demonstrated early cellular senescence (most of the endothelial cells senesced after one passage). Similarly, retinal pigmented epithelium cells derived from hiPSCs began senescing in the first passage. Before clinical application, it will be necessary to determine the cause and extent of such abnormalities and whether they also occur in hiPSCs generated using different reprogramming methods. PMID: 20155819 [PubMed - indexed for MEDLINE] | | |
| Endothelial bioreactor ameliorates endotoxemia sepsis in swine.
June 19, 2010 at 8:45 AM
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| | Endothelial bioreactor ameliorates endotoxemia sepsis in swine. Blood Purif. 2010;29(3):252-8 Authors: Xie Q, Liu J, Gu Y, Ping Y, You L, Zhong J, Li Y, Hasegawa H, Liang W, Lin S, Ding F INTRODUCTION: Severe sepsis involves a complex response including the activation of lots of cells, inflammatory mediators, and the hemostatic system. Central to this process is an alteration of endothelial cell function. Therefore, we investigated whether an endothelial bioreactor (EBR) would provide a new therapeutic approach to this clinical disorder. METHODS: EBR was constructed using a cartridge which contained with nonwoven polytetrafluoroethylene seeded with porcine iliac artery endothelial cell (PIEC). Pigs were intravenously administered with 0.25 mg/kg lipopolysaccharide and immediately placed in an extracorporeal circuit with EBR or sham controls. RESULTS: Compared with the sham group, EBR therapy resulted in significantly higher mean arterial blood pressure and significantly lower plasma von Willebrand factor, endothelin-1 and scores of lung injury. These alterations were associated with a significant survival advantage in the EBR group. CONCLUSIONS: Timely intervention with EC therapy in a tissue-engineered bioreactor may improve cardiovascular performance and alter the natural history of endotoxemia sepsis. PMID: 20016149 [PubMed - indexed for MEDLINE] | | |
| General overview of the sixth international symposium on stem cell therapy and cardiovascular innovations.
June 19, 2010 at 8:45 AM
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| | General overview of the sixth international symposium on stem cell therapy and cardiovascular innovations. J Cardiovasc Transl Res. 2010 Feb;3(1):1-7 Authors: Vázquez-Alvarez ME, Sanz-Ruiz R, Gutiérrez E, Villa A, Fernández ME, Vázquez S, Lorenzo MJ, Fernández L, Pascual I, Sánchez PL, Fernández-Avilés F Being one of the main stem cell therapy meetings of the year, the Sixth International Symposium on Stem Cell Therapy and Cardiovascular Innovations was held on April 23rd-24th, 2009, at the Auditorium of the High Council of Scientific Research of Spain (CSIC) in Madrid. Gathering the most prestigious basic researchers and clinical experts in the field of cardiovascular regenerative medicine, the aim of the meeting was to discuss the available evidence and the recent contributions from preclinical investigators, cardiologists, and cardiac surgeons in a participative translational fashion. The role of young "clinician scientists" was reinforced with a special poster session and three awards. The main conclusions of the symposium were (1) that standardization, larger clinical trials, and true translational research are needed, and (2) that new-allogeneic-stem cell products, biotechnological devices, and cell-based bioartificial organs are potentially exciting options for the future. PMID: 20560031 [PubMed - in process] | | |
| COMPARE-AMI Trial: Comparison of Intracoronary Injection of CD133(+) Bone Marrow Stem Cells to Placebo in Patients After Acute Myocardial Infarction and Left Ventricular Dysfunction: Study Rationale and Design.
June 19, 2010 at 8:45 AM
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| | COMPARE-AMI Trial: Comparison of Intracoronary Injection of CD133(+) Bone Marrow Stem Cells to Placebo in Patients After Acute Myocardial Infarction and Left Ventricular Dysfunction: Study Rationale and Design. J Cardiovasc Transl Res. 2010 Apr;3(2):153-9 Authors: Mansour S, Roy DC, Bouchard V, Nguyen BK, Stevens LM, Gobeil F, Rivard A, Leclerc G, Reeves F, Noiseux N Stem cell therapy has emerged as a promising approach to improve healing of the infarcted myocardium, to treat or prevent cardiac failure, and to restore lost cardiac function. Despite initial excitement, recent clinical trials using nonhomogenous human stem cells preparations showed variable results, raising concerns about the best cell type to transplant. Selected CD133(+) hematopoietic stem cells are promising candidate cells with great potential. COMPARE-acute myocardial infarction (AMI) study is a phase II, randomized, double-blind, placebo-controlled trial evaluating the safety and effectiveness of intracoronary CD133(+)-enriched hematopoietic bone marrow stem cells in patients with acute myocardial infarction and persistent left ventricular dysfunction. Patients who underwent successful percutaneous coronary intervention and present a persistent left ventricular ejection fraction <50% will be eligible to have bone marrow aspiration and randomized for intracoronary injection of selected CD 133(+) bone marrow cells vs placebo. The primary end point is a composite of a safety and efficacy end points evaluating the change at 4 months in the coronary atherosclerotic burden progression proximal and distal to the coronary stent in the infarct related artery; and the change in global left ventricular ejection fraction at 4 months relative to baseline as measured by magnetic resonance imaging. The secondary end point will be the occurrence of a major adverse cardiac event. To date, 14 patients were successfully randomized and treated without any protocol-related complication. COMPARE-AMI trial will help identify the effect of a selected population of the bone marrow stem cells on cardiac recovery of infarcted myocardium. PMID: 20560029 [PubMed - in process] | | |
| Stem cell biobanks.
June 19, 2010 at 8:45 AM
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| | Stem cell biobanks. J Cardiovasc Transl Res. 2010 Apr;3(2):128-34 Authors: Bardelli S Stem cells contribute to innate healing and harbor a promising role for regenerative medicine. Stem cell banking through long-term storage of different stem cell platforms represents a fundamental source to preserve original features of stem cells for patient-specific clinical applications. Stem cell research and clinical translation constitute fundamental and indivisible modules catalyzed through biobanking activity, generating a return of investment. PMID: 20560026 [PubMed - in process] | | |
| Hypoxia-inducible factor 1-alpha release after intracoronary versus intramyocardial stem cell therapy in myocardial infarction.
June 19, 2010 at 8:45 AM
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| | Hypoxia-inducible factor 1-alpha release after intracoronary versus intramyocardial stem cell therapy in myocardial infarction. J Cardiovasc Transl Res. 2010 Apr;3(2):114-21 Authors: Gyöngyösi M, Hemetsberger R, Posa A, Charwat S, Pavo N, Petnehazy O, Petrasi Z, Pavo IJ, Hemetsberger H, Benedek I, Benedek T, Benedek I, Kovacs I, Kaun C, Maurer G We have investigated the effect of stem cell delivery on the release of hypoxia-inducible factor 1 alpha (HIF-1alpha) in peripheral circulation and myocardium in experimental myocardial ischemia. Closed-chest, reperfused myocardial infarction (MI) was created in domestic pigs. Porcine mesenchymal stem cells (MSCs) were cultured and delivered (9.8 +/- 1.2 x 10(6)) either percutaneously NOGA-guided transendocardially (Group IM) or intracoronary (Group IC) 22 +/- 4 days post-MI. Pigs without MSC delivery served as sham control (Group S). Plasma HIF-1alpha was measured at baseline, immediately post- and at follow-up (FUP; 2 h or 24 h) post-MSC delivery by ELISA kit. Myocardial HIF-1alpha expression of infarcted, normal myocardium, or border zone was determined by Western blot. Plasma level of HIF-1alpha increased immediately post-MI (from 278 +/- 127 to 631 +/- 375 pg/ml, p < 0.05). Cardiac delivery of MSCs elevated the plasma levels of HIF-1alpha significantly (p < 0.05) in groups IC and IM immediately post-MSC delivery, and returned to baseline level at FUP, without difference between the groups IC and IM. The myocardial tissue HIF-1alpha expression in the infarcted area was higher in Group IM than in Group IC or S (1,963 +/- 586 vs. 1,307 +/- 392 vs. 271 +/- 110 activity per square millimeter, respectively, p < 0.05), while the border zone contained similarly lower level of HIF-1alpha, but still significantly higher as compared with Group S. Trend towards increase in myocardial expression of HIF-1alpha was measured in Group IM at 24 h, in contrast to Group IC. In conclusion, both stem cell delivery modes increase the systemic and myocardial level of HIF-1alpha. Intramyocardial delivery of MSC seems to trigger the release of angiogenic HIF-1alpha more effectively than does intracoronary delivery. PMID: 20560024 [PubMed - in process] | | |
| Stem cell therapy for chronic myocardial infarction.
June 19, 2010 at 8:45 AM
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| | Stem cell therapy for chronic myocardial infarction. J Cardiovasc Transl Res. 2010 Apr;3(2):79-88 Authors: Mazo M, Pelacho B, Prósper F Although recent advances for the treatment of myocardial infarction have dramatically increased the rate of survival after the ischemic event, this has also led to a rise in the number of chronic patients, making the finding of a suitable therapy a compulsory subject for modern medicine. Over the last decade, stem cells have been a promise for the cure of several diseases not only due to their plasticity but also to their capacity to act in a paracrine manner and influence the affected tissue, prompting the launching of several clinical trials. In spite of the knowledge already acquired, stem cell application to chronically infarcted hearts has been much less approached than its acute counterpart. Through this review, we will focus in stem cell therapy in animal models of chronic myocardial infarction: cell types employed, functional results, mechanisms analyzed, and questions raised. PMID: 20560022 [PubMed - in process] | | |
| Heart of Newt: A Recipe for Regeneration.
June 19, 2010 at 8:45 AM
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| | Heart of Newt: A Recipe for Regeneration. J Cardiovasc Transl Res. 2010 Jun 16; Authors: Singh BN, Koyano-Nakagawa N, Garry JP, Weaver CV The field of regenerative medicine holds tremendous promise for the treatment of chronic diseases. While the adult mammalian heart has limited regenerative capacity, previous studies have focused on cellular therapeutic strategies in an attempt to modulate cardiac regeneration. An alternative strategy relies on the modulation of endogenous stem/progenitor cells or signaling pathways to promote cardiac regeneration. Several organisms, including the newt, have an incomparable capacity for the regeneration of differentiated tissues. An enhanced understanding of the signals, pathways, and factors that mediate the regenerative response in these organisms may be useful in modulating the regenerative response of mammalian organs including the injured adult heart. PMID: 20559775 [PubMed - as supplied by publisher] | | |
| Stem cells in the diabetic infarcted heart.
June 19, 2010 at 8:45 AM
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| | Stem cells in the diabetic infarcted heart. Heart Fail Rev. 2010 Jun 18; Authors: Glass CE, Singal PK, Singla DK Diabetes mellitus is one of the leading causes of death, and the majority of these deaths are associated with cardiovascular diseases. Development and progression of myocardial infarction leading to heart failure is much more complex and multifactorial in diabetics compared with non-diabetics. Despite significant advances in pharmacological interventions and surgical techniques, the disease progression leading to diabetic end-stage heart failure remains very high. Recently, cell therapy has gained much attention as an alternative approach to treat various heart diseases. However, transplanted stem cell studies in diabetic animal models are very limited. In this review, we discuss the pathogenesis of the diabetic infarcted heart and the potential of stem cell therapy to repair and regenerate. PMID: 20559720 [PubMed - as supplied by publisher] | | |
| Factors Affecting Tissue Culture and Transplantation Using Omentum.
June 19, 2010 at 8:45 AM
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| | Factors Affecting Tissue Culture and Transplantation Using Omentum. ASAIO J. 2010 Jun 16; Authors: Kim JH, Kong WH, Seo SW In tissue engineering, a stable tissue layer and blood vessels are required for complete tissue formation, to provide structural strength and thickness and to supply oxygen and various nutrients. However, this has not been achieved using in vitro tissue-engineered culture techniques, thus many tissue engineering studies of trachea, bladder, and intestine reconstruction have used omentum. However, many factors critical to cell culture and transplantation using omentum have not yet been studied. For these reasons, we conducted a study of artificial trachea reconstruction in dogs using a poly(lactic-co-glycolic acid) (PLGA) porous scaffold, polypropylene prosthesis, and PKH26-labeled cells. We analyzed factors affecting tissue-engineered reconstruction using omentum, such as cell distribution and formation of cell layer and stability of transplant shape on omentum. As a result, we classified failure factors for tissue-engineered application of omentum and suggested three considerations for effective use of omentum in tissue engineering. Our observations may aid in the design and execution of future studies of omentum usage in tissue engineering. PMID: 20559129 [PubMed - as supplied by publisher] | | |
| Enhanced Reclosure of Surgically Induced Spinal Open Neural Tube Defects in Chick Embryos by Injecting Human Bone Marrow Stem Cells Into the Amniotic Cavity.
June 19, 2010 at 8:45 AM
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| | Enhanced Reclosure of Surgically Induced Spinal Open Neural Tube Defects in Chick Embryos by Injecting Human Bone Marrow Stem Cells Into the Amniotic Cavity. Neurosurgery. 2010 Jul;67(1):129-135 Authors: Lee DH, Phi JH, Kim SK, Cho BK, Kim SU, Wang KC OBJECTIVE: To evaluate the reclosure-promoting capacity of a neural stem cell line (F3) and a human bone marrow stem cell line (B10) injected into the amniotic cavity of spinal open neural tube defects (ONTDs) of chick embryos of Hamburger and Hamilton stage 18 or 19. METHODS: Fifteen chick embryos that survived the procedure were obtained for each of 4 groups: untreated control, F3-, B10-, and HFF-1 (human foreskin fibroblast)-treated groups. Embryos in the control group underwent ONTD surgery but no cell injection. RESULTS: Compared with the untreated control and HFF-1 groups, the B10 group showed enhanced reclosure at 3, 5, and 7 days after injection, whereas the F3 group did not. B10 cells were not incorporated into reclosed neural tubes but simply covered ONTDs during the process of reclosure. F3 cells did not cover ONTDs. The cell survival of F3 cells exposed to the chick amniotic fluid in vitro for 48 hours was significantly lower than that of B10 cells. CONCLUSION: The results confirmed that B10 cells enhance reclosure of ONTDs by covering and protecting neural tissues, not by direct cell incorporation. The lack of reclosure capacity in the F3 group may be related to the poor survival of F3 cells in the amniotic fluid. PMID: 20559100 [PubMed - as supplied by publisher] | | |
| Comparison of single high-dose streptozotocin with partial pancreatectomy combined with low-dose streptozotocin for diabetes induction in rhesus monkeys.
June 19, 2010 at 8:45 AM
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| | Comparison of single high-dose streptozotocin with partial pancreatectomy combined with low-dose streptozotocin for diabetes induction in rhesus monkeys. Exp Biol Med (Maywood). 2010 Jul 1;235(7):877-85 Authors: Jin X, Zeng L, He S, Chen Y, Tian B, Mai G, Yang G, Wei L, Zhang Y, Li H, Wang L, Qiao C, Cheng J, Lu Y Monkeys with insulin-dependent diabetes are important experimental models for islet xenotransplantation. However, with regard to diabetes induction, total pancreatectomy is a difficult operation with a high complication rate, while streptozotocin (STZ) administration may cause serious toxic effects and individual difference in metabolism. We compared two strategies involving pancreatectomy and STZ to successfully and safely induce diabetes in rhesus monkeys. Thirteen rhesus monkeys were divided into two groups: single high-dose STZ administration (80, 100 and 120 mg/kg, n = 3 for each dose) (group 1) and partial pancreatectomy (70-75%) combined with low-dose STZ (15 mg/kg, n = 4) (group 2). Induction of diabetes was evaluated by blood glucose, insulin, C-peptide, intravenous glucose tolerance test (IVGTT) and arginine stimulation test (AST). Detection of hematological and serum biochemical parameters and biopsies of pancreas, liver and kidney were periodically performed. In our study, animals in both groups developed diabetes. Serum C-peptide levels in groups 1 and 2 decreased to 0.08 +/- 0.07 and 0.35 +/- 0.06 nmol/L, respectively. IVGTT and AST indicated severely impaired glucose tolerance. Immunohistochemistry demonstrated that rare insulin-positive cells remained in the pancreas. In terms of STZ toxicity, four monkeys died 8-14 days after STZ administration (3 with 120 mg/kg STZ and 1 with 100 mg/kg STZ). Group 1 animals developed liver and kidney injury evidenced by increased alanine aminotransferase, aspartate aminotransferase, total cholesterol, LDL, triglyceride and blood urea nitrogen for one month, and histological abnormality including hepatic steatosis, renal glomerulus and tubular injury. Nevertheless, moderate histological injuries were seen in animals with 80 mg/kg STZ, with subsequent recovery. In contrast, group 2 animals displayed normal biochemical parameters and histology, with generally less risk of postoperative complications. We conclude that injection of 80 mg/kg STZ could induce diabetes with moderate injuries. Partial pancreatectomy with low-dose STZ is a safer and more reproducible method for inducing diabetes in rhesus monkeys. PMID: 20558842 [PubMed - in process] | | |
| Adipose Tissue-Derived Mesenchymal Stem Cells Facilitate Hematopoiesis In Vitro and In Vivo. Advantages Over Bone Marrow-Derived Mesenchymal Stem Cells.
June 19, 2010 at 8:45 AM
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| | Adipose Tissue-Derived Mesenchymal Stem Cells Facilitate Hematopoiesis In Vitro and In Vivo. Advantages Over Bone Marrow-Derived Mesenchymal Stem Cells. Am J Pathol. 2010 Jun 17; Authors: Nakao N, Nakayama T, Yahata T, Muguruma Y, Saito S, Miyata Y, Yamamoto K, Naoe T Mesenchymal stem cells (MSCs) have emerged as a new therapeutic modality for reconstituting the hematopoietic microenvironment by improving engraftment in stem cell transplantation. However, the availability of conventional bone marrow (BM)-derived MSCs (BMSCs) is limited. Recent studies showed that a large number of MSCs can be easily isolated from fat tissue (adipose tissue-derived MSCs [ADSCs]). In this study, we extensively evaluated the hematopoiesis-supporting properties of ADSCs, which are largely unknown. In vitro coculture and progenitor assays showed that ADSCs generated significantly more granulocytes and progenitor cells from human hematopoietic stem cells (HSCs) than BMSCs. We found that ADSCs express the chemokine CXCL12, a critical regulator of hematopoiesis, at levels that are three fold higher than those with BMSCs. The addition of a CXCL12 receptor antagonist resulted in a lower yield of granulocytes from ADSC layers, whereas the addition of recombinant CXCL12 to BMSC cocultures promoted the growth of granulocytes. In vivo cell homing assays showed that ADSCs facilitated the homing of mouse HSCs to the BM better than BMSCs. ADSCs injected into the BM cavity of fatally irradiated mice reconstituted hematopoiesis more promptly than BMSCs and subsequently rescued mice that had received a low number of HSCs. Secondary transplantation experiments showed that ADSCs exerted favorable effects on long-term HSCs. These results suggest that ADSCs can be a promising therapeutic alternative to BMSCs. PMID: 20558580 [PubMed - as supplied by publisher] | | |
| In Vivo Assessment of Acute UVB Responses in Normal and Xeroderma Pigmentosum (XP-C) Skin-Humanized Mouse Models.
June 19, 2010 at 8:45 AM
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| | In Vivo Assessment of Acute UVB Responses in Normal and Xeroderma Pigmentosum (XP-C) Skin-Humanized Mouse Models. Am J Pathol. 2010 Jun 17; Authors: GarcÃa M, Llames S, GarcÃa E, Meana A, Cuadrado N, Recasens M, Puig S, Nagore E, Illera N, Jorcano JL, Del Rio M, Larcher F In vivo studies of UVB effects on human skin are precluded by ethical and technical arguments on volunteers and inconceivable in cancer-prone patients such as those affected with Xeroderma Pigmentosum (XP). Establishing reliable models to address mechanistic and therapeutic matters thus remains a challenge. Here we have used the skin-humanized mouse system that circumvents most current model constraints. We assessed the UVB radiation effects including the sequential changes after acute exposure with respect to timing, dosage, and the relationship between dose and degree-sort of epidermal alteration. On Caucasian-derived regenerated skins, UVB irradiation (800 J/m(2)) induced DNA damage (cyclobutane pyrimidine dimers) and p53 expression in exposed keratinocytes. Epidermal disorganization was observed at higher doses. In contrast, in African descent-derived regenerated skins, physiological hyperpigmentation prevented tissue alterations and DNA photolesions. The acute UVB effects seen in Caucasian-derived engrafted skins were also blocked by a physical sunscreen, demonstrating the suitability of the system for photoprotection studies. We also report the establishment of a photosensitive model through the transplantation of XP-C patient cells as part of a bioengineered skin. The inability of XP-C engrafted skin to remove DNA damaged cells was confirmed in vivo. Both the normal and XP-C versions of the skin-humanized mice proved proficient models to assess UVB-mediated DNA repair responses and provide a strong platform to test novel therapeutic strategies. PMID: 20558577 [PubMed - as supplied by publisher] | | |
| Angiomyeloproliferative Lesions Following Autologous Stem Cell Therapy.
June 19, 2010 at 8:45 AM
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| | Angiomyeloproliferative Lesions Following Autologous Stem Cell Therapy. J Am Soc Nephrol. 2010 Jun 17; Authors: Thirabanjasak D, Tantiwongse K, Thorner PS Some reports suggest that autologous hematopoietic stem cell transplantation holds potential for treatment of renal diseases such as lupus nephritis, but the safety of delivering various stem cell types (hematopoietic, mesenchymal, and endothelial precursors) is not well established. Here, we report a case of lupus nephritis treated by direct renal injection of autologous stem cells recovered from peripheral blood. The patient developed masses at the sites of injection and hematuria. We suspected transitional cell carcinoma but nephrectomy revealed that the masses were angiomyeloproliferative lesions. We believe that this previously undescribed pathologic entity is stem cell-derived or -induced. The biologic potential, including the neoplastic potential, of this lesion is unknown. This case illustrates that the development of angiomyeloproliferative lesions is a possible complication of stem cell therapy. PMID: 20558536 [PubMed - as supplied by publisher] | | |
| Examination of cell-host-biomaterial interactions via high-throughput technologies: A re-appraisal.
June 19, 2010 at 8:45 AM
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| | Examination of cell-host-biomaterial interactions via high-throughput technologies: A re-appraisal. Biomaterials. 2010 Jun 15; Authors: Power KA, Fitzgerald KT, Gallagher WM Biomaterials are required to act harmoniously when exposed to the body or bodily fluids. Investigating cellular or in vivo phenotypic responses and protein adsorption to the material surface helps to determine the associated biocompatibility. Past limitations on progress in this field include time-consuming cell-based screening tools and a limited understanding of the complex nature of cell-biomaterial interactions. While high-throughput technologies by their nature are a rapid tool to derive meaning from multifaceted systems and, in recent years, the biomaterial community is beginning to take advantage of these technologies, the key observation in this Leading Opinion Paper is that the biomaterials community has been slow to accept these methods as an addition to their traditional experimentation workflow. The purpose of this paper is to review the definition and recent usage of high-throughput experiments in order to examine biomaterial interactions at the cellular and wider host level, especially as they become more relevant within the biomaterials arena encapsulating tissue engineering, gene, drug and stem cell delivery systems. The technologies under focus include rapid cell-based screening, transcriptomics and proteomics. PMID: 20557931 [PubMed - as supplied by publisher] | | |
| n-Hydroxyapatite/PCL-Pluronic-PCL Nanocomposites for Tissue Engineering. Part 2: Thermal and Tensile Study.
June 19, 2010 at 8:45 AM
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| | n-Hydroxyapatite/PCL-Pluronic-PCL Nanocomposites for Tissue Engineering. Part 2: Thermal and Tensile Study. J Biomater Sci Polym Ed. 2010 Jun 16; Authors: Fu S, Guo G, Wang X, Zhou L, Gong C, Luo F, Zhao X, Wei Y, Qian Z In this work a series of nano-hydroxyapatite/poly(epsilon-caprolactone)-Pluronic-poly(epsilon-caprolactone) (n-HA/ PCFC) nanocomposites has been prepared. Thermal properties of the nanocomposites are studied by thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). The TGA/DTG results reveal that thermal stability of n-HA/PCFC nanocomposites is improved by incorporation of n-HA into polymer matrix, and the thermo-degradation temperature increased slightly with increasing HA loading. DSC results show that the glass transition temperature (T(g)) changed by the addition of n-HA. The mechanical properties of the nanocomposites are investigated by tensile testing. The morphology for tensile-fractured surfaces of nanocomposites is observed by scanning electron microscopy. The effect of n-HA contents of nanocomposites on tensile strength and morphology is also discussed. PMID: 20557698 [PubMed - as supplied by publisher] | | |
| Degradation Behavior of 3D Porous Polydioxanone-b-Polycaprolactone Scaffolds Fabricated Using the Melt-Molding Particulate-Leaching Method.
June 19, 2010 at 8:45 AM
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| | Degradation Behavior of 3D Porous Polydioxanone-b-Polycaprolactone Scaffolds Fabricated Using the Melt-Molding Particulate-Leaching Method. J Biomater Sci Polym Ed. 2010 Jun 16; Authors: Oh SH, Park SC, Kim HK, Koh YJ, Lee JH, Lee MC, Lee JH Recently, polydioxanone (PDO) and polycaprolactone (PCL) have been applied in applications for tissue engineering owing to their flexibility, as well as biocompatibility and biodegradability, even though their degradation rates are usually either too fast or too slow for many applications. In this study, we synthesized poly(dioxanone-b-caprolactone) co-polymers (PDOCLs) with different DO/CL ratio (0:10-10:0) by ring-opening polymerization. The synthesized co-polymers were characterized by (1)H-NMR, the measurement of inherent viscosity (IV), GPC and DSC. PDOCL scaffolds with different DO/CL ratio were fabricated by a melt-molding particulate-leaching method without using any organic solvents during the scaffold fabrication process. The degradation behavior (in vitro) of the PDOCL scaffolds was evaluated in PBS at 37 degrees C for up to 56 days by the changes in molecular weight, mechanical strength, gross weight and pH. It was observed that the degradation rate of PDOCL scaffolds could be controlled by adjusting the DO/CL ratio of the co-polymers (increasing CL composition leads to slower degradation rate). The PDOCL scaffolds did not lead to a significant drop in pH during the degradation, not even for the PDO-dominant PDOCL scaffolds showing a fast degradation rate, indicating the formation of a small amount of acidic by-products compared to the PLGA scaffolds. From the results, it was expected that the PDOCLs can be a new flexible scaffolding material with different degradation rate for various tissue-engineering applications. PMID: 20557697 [PubMed - as supplied by publisher] | | |
| Cellular Behavior on Epidermal Growth Factor (EGF)-Immobilized PCL/Gelatin Nanofibrous Scaffolds.
June 19, 2010 at 8:45 AM
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| | Cellular Behavior on Epidermal Growth Factor (EGF)-Immobilized PCL/Gelatin Nanofibrous Scaffolds. J Biomater Sci Polym Ed. 2010 Jun 16; Authors: Tığlı RS, Kazaroğlu NM, Mav İ Ş B, Gümüşderel İ Oğlu M Nano-scaled poly(epsilon-caprolactone) (PCL) and PCL/gelatin fibrous scaffolds with immobilized epidermal growth factor (EGF) were prepared for the purpose of wound-healing treatments. The tissue scaffolds were fabricated by electrospinning and the parameters that affect the electrospinning process were optimized. While the fiber diameters were 488+/-114 nm and 663+/-107 nm for PCL and PCL/gelatin scaffolds, respectively, the porosities were calculated as 79% for PCL and 68% for PCL/gelatin scaffolds. Electrospun PCL and PCL/gelatin scaffolds were first modified with 1,6-diaminohexane to introduce amino groups on their surfaces, then EGF was chemically conjugated to the surface of nanofibers. The results obtained from Attenuated Total Reflectance Fourier Transform Infrared (ATR-FT-IR) spectroscopy and quantitative measurements showed that EGF was successfully immobilized on nanofibrous scaffolds. L929 mouse fibroblastic cells were cultivated on both neat and EGF-immobilized PCL and PCL/gelatin scaffolds in order to investigate the effect of EGF on cell spreading and proliferation. According to the results, especially EGF-immobilized PCL/gelatin scaffolds exerted early cell spreading and superior and rapid proliferation compared to EGF-immobilized PCL scaffolds and neat PCL, PCL/gelatin scaffolds. Consequently, EGF-immobilized PCL/gelatin scaffolds could potentially be employed as novel scaffolds for skin tissue-engineering applications. PMID: 20557696 [PubMed - as supplied by publisher] | | |
| Fabrication of Chitosan Scaffolds with Tunable Porous Orientation Structure for Tissue Engineering.
June 19, 2010 at 8:45 AM
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| | Fabrication of Chitosan Scaffolds with Tunable Porous Orientation Structure for Tissue Engineering. J Biomater Sci Polym Ed. 2010 Jun 16; Authors: Wen P, Gao J, Zhang Y, Li X, Long Y, Wu X, Zhang Y, Guo Y, Xing F, Wang X, Qiu H, Liu Y Chitosan, as an example of natural macromolecular biomaterials, was used to fabricate highly porous chitosan scaffolds with microtubules having a tubular orientation structure using the unidirectional freeze-drying method. The porous structure of the scaffolds was characterized via scanning electron microscopy. The factors that affect the porous structure of the scaffolds, such as the concentration of chitosan solution and addition of glutaraldehyde as cross-linking agent, have been extensively studied in order to find a facile and efficient way to control the porosity, tubular morphology and orientation of the microtubules. The properties of the chitosan scaffolds, including water absorption ability, compressive strength, protein adsorption and in vitro enzymatic biodegradation in the presence of lysozyme, were also investigated. In vitro cell-culture results showed that the chitosan scaffold was non-toxic to cartilage cells and the cells could spread and grow well on the scaffolds. PMID: 20557692 [PubMed - as supplied by publisher] | | |
| Citric-Acid-Derived Photo-cross-Linked Biodegradable Elastomers.
June 19, 2010 at 8:45 AM
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| | Citric-Acid-Derived Photo-cross-Linked Biodegradable Elastomers. J Biomater Sci Polym Ed. 2010 Jun 16; Authors: Gyawali D, Tran RT, Guleserian KJ, Tang L, Yang J Citric-acid-derived thermally cross-linked biodegradable elastomers (CABEs) have recently received significant attention in various biomedical applications, including tissue-engineering orthopedic devices, bioimaging and implant coatings. However, citric-acid-derived photo-cross-linked biodegradable elastomers are rarely reported. Herein, we report a novel photo-cross-linked biodegradable elastomer, referred to as poly(octamethylene maleate citrate) (POMC), which preserves pendant hydroxyl and carboxylic functionalities after cross-linking for the potential conjugation of biologically active molecules. Pre-POMC is a low-molecular-mass pre-polymer with an average molecular mass between 701 and 1291 Da. POMC networks are soft and elastic with an initial modulus of 0.07 to 1.3 MPa and an elongation-at-break between 38 and 382%. FT-IR-ATR results confirmed the successful surface immobilization of type-I collagen onto POMC films, which enhanced in vitro cellular attachment and proliferation. Photo-polymerized POMC films implanted subcutaneously into Sprague-Dawley rats demonstrated minimal in vivo inflammatory responses. The development of POMC enriches the family of citric-acid-derived biodegradable elastomers and expands the available biodegradable polymers for versatile needs in biomedical applications. PMID: 20557687 [PubMed - as supplied by publisher] | | |
| A Poly(lactic-co-glycolic acid) Knitted Scaffold for Tendon Tissue Engineering: An In Vitro and In Vivo Study.
June 19, 2010 at 8:45 AM
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| | A Poly(lactic-co-glycolic acid) Knitted Scaffold for Tendon Tissue Engineering: An In Vitro and In Vivo Study. J Biomater Sci Polym Ed. 2010 Jun 16; Authors: Vaquette C, Slimani S, Kahn CJ, Tran N, Rahouadj R, Wang X We have designed a composite scaffold for potential use in tendon or ligament tissue engineering. The composite scaffold was made of a cellularized alginate gel that encapsulated a knitted structure. Our hypothesis was that the alginate would act as a cell carrier and deliver cells to the injury site while the knitted structure would provide mechanical strength to the composite construct. The mechanical behaviour and the degradation profile of the poly(lactic-co-glycolic acid) knitted scaffolds were evaluated. We found that our scaffolds had an elastic modulus of 750 MPa and that they lost their physical integrity within 7 weeks of in vitro incubation. Autologous rabbit mesenchymal stem cell seeded composite scaffolds were implanted in a 1-cm-long defect created in the rabbit tendon, and the biomechanical properties and the morphology of the regenerated tissues were evaluated after 13 weeks. The regenerated tendons presented higher normalized elastic modulus of (60%) when compared with naturally healed tendons (40%). The histological study showed a higher cell density and vascularization in the regenerated tendons. PMID: 20557686 [PubMed - as supplied by publisher] | | | | 
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