|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | Tissue Engineering Strategies for Immature Teeth with Apical Periodontitis. J Endod. 2011 Mar;37(3):390-397 Authors: Yamauchi N, Yamauchi S, Nagaoka H, Duggan D, Zhong S, Lee SM, Teixeira FB, Yamauchi M INTRODUCTION: Regenerative endodontic treatment on immature teeth with apical periodontitis is promising but still not well-established. The purpose of this study was to explore novel strategies to engineer a vital support structure within a root canal space by a combination of induced blood clot, exposure of dentin matrix, and a cross-linked collagen scaffold. METHODS: Apical periodontitis was induced in 6 dogs with immature teeth (n = 64). After disinfection, the following groups were randomly assigned: blood clot (BC) alone, BC with a cross-linked collagen scaffold (CCS), BC with exposure of dentin matrix by ethylenediaminetetraacetic acid (EDTA), and BC with CCS and EDTA. Positive (infected only) and negative controls (untreated) were also included. The dogs were followed up for 3.5 months and killed. Periradicular healing and root wall thickening were radiographically analyzed and statistically evaluated. The jaws were then fixed, demineralized, and subjected to histologic analyses. Newly formed mineralized tissues were histomorphometrically analyzed, quantified, and statistically evaluated. RESULTS: Radiographically there was significant difference in periradicular healing and root wall thickening (P < .05). Histomorphometric analysis showed significantly more mineralized tissue formation in the groups containing the scaffold (P < .05). Exposure of the dentin matrix by EDTA appeared to increase the adherence of the newly formed mineralized tissue to the root walls. CONCLUSIONS: The use of cross-linked collagen scaffold and exposure of dentin matrix combined with blood clot might provide an efficient approach to generate a vital support structure for the treatment of immature teeth with apical periodontitis. PMID: 21329828 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Platelet-rich plasma (PRP) enhances bone healing in non-united critical-sized defects: A preliminary study involving rabbit models. Injury. 2011 Feb 15; Authors: Kanthan SR, Kavitha G, Addi S, Choon DS, Kamarul T INTRODUCTION: The use of bone grafts in treating non- or delayed unions as the result of large bone loss is well established. However, despite good outcomes, the time to achieve complete union is still considerably long. To overcome this problem, the use of platelet-rich plasma (PRP) has been advocated albeit with varying success. To determine the true effectiveness of PRP in treating non-/delayed unions, a study was conducted using (n=12) rabbit models. METHODS AND MATERIALS: Critical-sized defects measuring 2cm created in the midshaft of the right rabbit tibias were stabilised using 2.7-mm small fragment plates. A spacer placed in the defects to create a delay in bone union was replaced at 3 weeks with artificial bone grafts (Coragraft(®)), with or without PRP. The operated limbs were radiographed following the defect creation and at 3, 7 and 11 weeks (at sacrifice). Bone healing and histological changes were later assessed and scored using the appropriate grading systems. Four groups were compared for quality of healing: (group-A) control group, that is, no PRP or Coragraft; (group-B) PRP; (group-C) Coragraft; and (group-D) PRP and Coragraft. RESULTS: Group-D demonstrated the best bone healing based on radiological, histological and gross findings (Kruskall-Wallis: p<0.05). Group-C had significantly higher scores than group-B, whilst group-A had significantly lower scores than all other groups (Mann-Whitney U: p<0.05). CONCLUSION: The use of PRP with bone graft significantly improves the quality of bone healing. However, the use of PRP without bone substitute does not provide adequate repair tissue and, therefore, provides little benefit when used independently. PMID: 21329922 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Nanoengineering a biocompatible inorganic scaffold for skin wound healing. J Biomed Nanotechnol. 2010 Oct;6(5):497-510 Authors: Poinern GE, Fawcett D, Ng YJ, Ali N, Brundavanam RK, Jiang ZT Tissue engineering is a multidisciplinary field that can directly benefit from advancements in nanotechnology and nanoscience. This article reviews a representative selection of commercially available procedures and techniques used to treat different degrees of skin burns. It also explores the emerging novel biocompatible inorganic nano-engineered alumina membrane in terms of skin wound healing. PMID: 21329044 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Stem Cells in Tooth Tissue Regeneration-Challenges and Limitations. Stem Cell Rev. 2011 Feb 18; Authors: Inanç B, Elçin YM The accelerated pace of research in the stem cell field in recent decades and the accumulated body of knowledge has spurred the interest in potential clinical applications of stem cells in all branches of medicine including regenerative dentistry. In humans, embryonic and adult stem cells are two major groups of cells that can serve as a donor source in tissue engineering strategies based on ex-vivo cellular expansion. It has been shown that adult stem cell populations are present in all examined living tissues of the organism, thus being a crucial source of tissue homeostasis and regeneration, and offering a target population for in situ stimulation of extensive tissue regeneration. Experimental findings indicate that in the complex structure of the tooth organ, both periodontal and endodontic tissues harbour adult stem cells with characteristics peculiar to early stages of cellular differentiation. Myriad of strategies incorporating both embryonic and adult stem cells for the regeneration of a particular tooth structure or the whole teeth were proposed; however their successful application to solve real problems encountered in the clinical practice of dentistry remains an elusive and challenging objective. PMID: 21331452 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adult Human Adipose Tissue Contains Several Types of Multipotent Cells. J Cardiovasc Transl Res. 2011 Feb 15; Authors: Tallone T, Realini C, Böhmler A, Kornfeld C, Vassalli G, Moccetti T, Bardelli S, Soldati G Multipotent mesenchymal stromal cells (MSCs) are a type of adult stem cells that can be easily isolated from various tissues and expanded in vitro. Many reports on their pluripotency and possible clinical applications have raised hopes and interest in MSCs. In an attempt to unify the terminology and the criteria to label a cell as MSC, in 2006 the International Society for Cellular Therapy (ISCT) proposed a standard set of rules to define the identity of these cells. However, MSCs are still extracted from different tissues, by diverse isolation protocols, are cultured and expanded in different media and conditions. All these variables may have profound effects on the selection of cell types and the composition of heterogeneous subpopulations, on the selective expansion of specific cell populations with totally different potentials and ergo, on the long-term fate of the cells upon in vitro culture. Therefore, specific molecular and cellular markers that identify MSCs subsets as well as standardization of expansion protocols for these cells are urgently needed. Here, we briefly discuss new useful markers and recent data supporting the rapidly emerging concept that many different types of progenitor cells are found in close association with blood vessels. This knowledge may promote the necessary technical improvements required to reduce variability and promote higher efficacy and safety when isolating and expanding these cells for therapeutic use. In the light of the discussed data, particularly the identification of new markers, and advances in the understanding of fundamental MSC biology, we also suggest a revision of the 2006 ISCT criteria. PMID: 21327755 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | How and why does the proteome respond to microgravity? Expert Rev Proteomics. 2011 Feb;8(1):13-27 Authors: Grimm D, Wise P, Lebert M, Richter P, Baatout S For medical and biotechnological reasons, it is important to study mammalian cells, animals, bacteria and plants exposed to simulated and real microgravity. It is necessary to detect the cellular changes that cause the medical problems often observed in astronauts, cosmonauts or animals returning from prolonged space missions. In order for in vitro tissue engineering under microgravity conditions to succeed, the features of the cell that change need to be known. In this article, we summarize current knowledge about the effects of microgravity on the proteome in different cell types. Many studies suggest that the effects of microgravity on major cell functions depend on the responding cell type. Here, we discuss and speculate how and why the proteome responds to microgravity, focusing on proteomic discoveries and their future potential. PMID: 21329425 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Gastroparesis: Approach, Diagnostic Evaluation, and Management. Dis Mon. 2011 Feb;57(2):74-101 Authors: Tang DM, Friedenberg FK Gastroparesis is a chronic motility disorder of the stomach that involves delayed emptying of solids and liquids, without evidence of mechanical obstruction. Although no cause can be determined for the majority of cases, the disease often develops as a complication of abdominal surgeries or because of other underlying disorders, such as diabetes mellitus or scleroderma. The pathophysiology behind delayed gastric emptying is still not well-understood, but encompasses abnormalities at 3 levels-autonomic nervous system, smooth muscle cells, and enteric neurons. Patients will often cite nausea, vomiting, postprandial fullness, and early satiety as their most bothersome symptoms on history and physical examination. Those that present with severe disease may already have developed complications, such as the formation of bezoars or masses of undigested food. In patients suspected of gastroparesis, diagnostic evaluation requires an initial upper endoscopy to rule out mechanical causes, followed by a gastric-emptying scintigraphy for diagnosis. Other diagnostic alternatives would be wireless capsule motility, antroduodenal manometry, and breath testing. Once gastroparesis is diagnosed, dietary modifications, such as the recommendation of more frequent and more liquid-based meals, are encouraged. Promotility medications like erythromycin and antiemetics like prochlorperazine are offered for symptomatic relief. These agents may be frequently changed, as the right combination of effective medications will vary with each individual. In patients who are refractory to pharmacologic treatment, more invasive options, such as intrapyloric botulinum toxin injections, placement of a jejunostomy tube, or implantation of a gastric stimulator, are considered. Future areas of research are based on current findings from clinical studies. New medications, such as hemin therapy, are emerging because of a better understanding of the pathophysiology behind gastroparesis, and present treatment options, such as gastric electric stimulation, are evolving to be more effective. Regenerative medicine and stem cell-based therapies also hold promise for gastroparesis in the near future. PMID: 21329779 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A scaffold-free in vitro model for osteogenesis of human mesenchymal stem cells. Tissue Cell. 2011 Feb 15; Authors: Hildebrandt C, Büth H, Thielecke H For studying cellular processes three-dimensional (3D) in vitro models are of a high importance. For tissue engineering approaches osseous differentiation is performed on 3D scaffolds, but material depending influences promote cellular processes like adhesion, proliferation and differentiation. To investigate developmental processes of mesenchymal stem cells without cell-substrate interactions, self-contained in vitro models mimicking physiological condition are required. However, with respect to scientific investigations and pharmaceutical tests, it is essential that these tissue models are well characterised and are of a high reproducibility. In order to establish an appropriate in vitro model for bone formation, different protocols are compared and optimised regarding their aggregate formation efficiency, homogeneity of the aggregates, the viability and their ability to induce differentiation into the osteogenic lineage. The protocols for the generation of 3D cell models are based on rotation culture, hanging drop technique, and the cultivation in non adhesive culture vessels (single vessels as well as 96 well plates). To conclude, the cultivation of hMSCs in 96 well non adhesive plates facilitates an easy way to cultivate homogenous cellular aggregates with high performance efficiency in parallel. The size can be controlled by the initial cell density per well and within this spheroids, bone formation has been induced. PMID: 21329953 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |  | |  | |  |
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