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Sample records for cemented stem clinical

  1. The influence of cement mantle thickness and stem geometry on fatigue damage in two different cemented hip femoral prostheses.

    Science.gov (United States)

    Ramos, A; Simões, J A

    2009-11-13

    Experimental models can be used for pre-clinical testing of cemented and other type of hip replacements. Total hip replacement (THR) failure scenarios include, among others, cement damage accumulation and the assessment of accurate stress and strain magnitudes at the cement mantle interfaces (stem-cement and cement-bone) can be used to predict mechanical failure. The aseptic loosening scenario in cemented hip replacements is currently not fully understood, and methods of evaluating medical devices must be developed to improve clinical performance. Different results and conclusions concerning the cement micro-cracking mechanism have been reported. The aim of this study was to verify the in vitro behavior of two cemented femoral stems with respect to fatigue crack formation. Fatigue crack damage was assessed at the medial, lateral, anterior and posterior sides of the Lubinus SPII and Charnley stems. All stems were loaded and tested in stair climbing fatigue loading during one million cycles at 2 Hz. After the experiments each implanted synthetic femur was sectioned and analyzed. We observed more damage (cracks per area) for the Lubinus SPII stem, mainly on the proximal part of the cement mantle. The micro-cracking formation initiated in the stem-cement interface and grew towards the direction of cortical bone of the femur. Overall, the cement-bone interface seems to be crucial for the success of the hip replacement. The Charnley stem provoked more damage on the cement-bone interface. A failure index (maximum length of crack/maximum thickness of cement) considered was higher for the cement-stem interface of the Lubinus SPII stem. For a cement mantle thickness higher than 5 mm, cracking initiated at the cement-bone interface and depended on the opening canal process (reaming procedure and instrumentation). The analysis also showed that fatigue-induced damage on the cement mantle, increasing proximally, and depended on the axial position of the stem. The cement

  2. The importance of a thick cement mantle depends on stem geometry and stem-cement interfacial bonding.

    Science.gov (United States)

    Caruana, J; Janssen, D; Verdonschot, N; Blunn, G W

    2009-04-01

    The thickness of the cement mantle around the femoral component of total hip replacements is a contributing factor to aseptic loosening and revision. Nevertheless, various designs of stems and surgical tooling lead to cement mantles of different thicknesses. Opinion is divided on whether a thick mantle enhances implant longevity. This study investigates the effect of cement mantle thickness on accumulated damage in the cement, and how this is influenced by the presence or absence of a proximal collar and on whether the stem-cement interface remains bonded. Three-dimensional finite element simulations incorporating creep and non-linear damage accumulation were performed to investigate cracking in the cement mantles around Stanmore Hips under physiologically informed stair-climbing and gait loads. Cement mantle thickness, stem-cement interfacial bonding, and collar design were varied to assess the interactive effects of these parameters. In all cases, damage levels were three to six times higher when the stem-cement interface remained bonded. Cement mantle thickness had little effect on cement damage accumulation around debonded collared stems but was critical in both bonded and collarless cases, where a thicker mantle reduced cement cracking. Damage around a smooth debonded stem with a collar is thus much less sensitive to cement thickness than around bonded or collarless stems. PMID:19405437

  3. The effect of adding tobramycin to Simplex P cement on femoral stem micromotion as measured by radiostereometric analysis

    OpenAIRE

    Bohm, Eric; Petrak, Martin; Gascoyne, Trevor; Turgeon, Thomas

    2012-01-01

    Background Previous in vitro research on addition of antibiotics to bone cement has found no statistically significant deterioration in mechanical properties. However, no clinical studies have compared the performance of tobramycin-laden bone cement with that of standard bone cement (Simplex P). Patients and Methods 23 patients (25 hips) were randomized to receive an Exeter (Stryker Orthopaedics) femoral stem cemented with either Simplex P (standard) or Simplex T (tobramycin-laden) cement. Th...

  4. Galvanically enhanced fretting-crevice corrosion of cemented femoral stems

    OpenAIRE

    Bryant, M.; Farrar, R; Freeman, R; Brummitt, K; J. Nolan; Neville, A

    2014-01-01

    The Ultima TPS MoM THR was designed and developed as a 2nd generation MoM THR specifically aimed at younger more active patients due to the anticipated low wear rates and increased longevity of MoM THRs. In 2010, published clinical data highlighted the early failure of the Ultima TPS MoM due to fretting-crevice corrosion at the stem-cement interface. Since 2010 similar observations have been reported by other clinical centres implicating competitor products as well as the Ultima TPS MoM THR. ...

  5. Effects of a discoloration-resistant calcium aluminosilicate cement on the viability and proliferation of undifferentiated human dental pulp stem cells

    OpenAIRE

    Li-na Niu; Devon Watson; Kyle Thames; Carolyn M. Primus; Bergeron, Brian E.; Kai Jiao; Bortoluzzi, Eduardo A.; Cutler, Christopher W.; Ji-hua Chen; PASHLEY David H.; Franklin R Tay

    2015-01-01

    Discoloration-resistant calcium aluminosilicate cement has been formulated to overcome the timely problem of tooth discoloration reported in the clinical application of bismuth oxide-containing hydraulic cements. The present study examined the effects of this experimental cement (Quick-Set2) on the viability and proliferation of human dental pulp stem cells (hDPSCs) by comparing the cellular responses with commercially available calcium silicate cement (white mineral trioxide aggregate; WMTA)...

  6. Practical clinical considerations of luting cements: A review

    OpenAIRE

    Lad, Pritam P; Kamath, Maya; Tarale, Kavita; Kusugal, Preethi B

    2014-01-01

    The longevity of fixed partial denture depends on the type of luting cement used with tooth preparation. The clinician’s understating of various cements, their advantages and disadvantages is of utmost importance. In recent years, many luting agents cements have been introduced claiming clinically better performance than existing materials due to improved characteristics. Both conventional and contemporary dental luting cements are discussed here. The various agents discussed are: Zinc pho...

  7. Practical clinical considerations of luting cements: A review.

    Science.gov (United States)

    Lad, Pritam P; Kamath, Maya; Tarale, Kavita; Kusugal, Preethi B

    2014-02-01

    The longevity of fixed partial denture depends on the type of luting cement used with tooth preparation. The clinician's understating of various cements, their advantages and disadvantages is of utmost importance. In recent years, many luting agents cements have been introduced claiming clinically better performance than existing materials due to improved characteristics. Both conventional and contemporary dental luting cements are discussed here. The various agents discussed are: Zinc phosphate, Zinc polycarboxylate, Zinc oxide-eugenol, Glass-ionomer, Resin modified GIC, Compomers and Resin cement. The purpose of this article is to provide a discussion that provides a clinical perspective of luting cements currently available to help the general practitioner make smarter and appropriate choices. How to cite the article: Lad PP, Kamath M, Tarale K, Kusugal PB. Practical clinical considerations of luting cements: A review. J Int Oral Health 2014;6(1):116-20. PMID:24653615

  8. Impact of stem-broach sizing on the cement mantle of Lubinus SP II stems. A CT scan analysis.

    Science.gov (United States)

    Scheerlinck, Thierry; de Mey, Johan; Deklerck, Rudi

    2009-06-01

    Lubinus SP II stems are cemented either line-to-line with the largest broach or one-size undersized. The purpose of this study was to compare both implantation techniques. We used 18 polymeric stem replicas cemented line-to-line and undersized in paired cadaveric femora and analyzed them with CT scan images. Cementing Lubinus stems line-to-line resulted in higher medullary canal-filling indices (28.26 +/- 4.10%), thinner cement mantles (3.29 +/- 0.40 mm), more cement defects (5.12 +/- 1.69%) and more areas of thin cement (23.81 +/- 7.13%) than undersizing (respectively: 23.61 +/- 4.24%, 3.62 +/- 0.43 mm, 1.48 +/- 2.04%, 15.11 +/- 5.93%). In both settings, over 80% of areas of thin or deficient cement were supported by cortex. Using a line-to-line technique, adequate stem alignment was achieved without distal centralizer. Undersizing the stem and using a distal centralizer reduced the incidence of distal cement defects by a factor 10. While stems cemented line-to-line might have mechanical advantages, undersizing and using distal centralizers reduced potential pathways for debris migration to the bone-cement interface. PMID:19681321

  9. Development of Clinical Cement of Nanoapatite and Polyamide Composite

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new type of inorganicorganic biomimetic bone cement consisting of nanohydroxyapatite and polyamide 66 composite was investigated. This cement can be handled as paste and easily shaped into any contour. Nanoapatite and polyamide composite cement has a reasonable setting time, excellent washout resistance, high mechanical strength and bioactivity, and it is easily handled and shaped, which can be developed as a clinical cement. It can be predicted that nanoapatite/polymer composite cement would be a new trend of biomedical material, showing a promising prospect.

  10. Development and clinical trial of a novel bioactive bone cement

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Strontium(Sr)and related compounds have become more attractive in the prevention and treatment of osteoporosis.Previously,we developed a novel bioactive bone cement which is mainly composed of strontium-containing hydroxyapatite(Sr-HA)filler and bisphenol A diglycidylether dimethacrylate(Bis-GMA)resin.This bone cement is superior to conventional polymethylmethacrylate (PMMA)bone cement in bioactivity,biocompatibility,and osseointegration.It also has shown sufficient mechanical strength properties for its use in percutaneous vertebroplasty(PVP)and total hip replacement(THR).In this paper,we review the in vitro,in vivo and clinical evidence for the effectiveness of this bioactive bone cement.

  11. A new design of cemented stem using functionally graded materials (FGM).

    Science.gov (United States)

    Hedia, H S; Aldousari, S M; Abdellatif, A K; Fouda, N

    2014-01-01

    One of the most frequent complications of total hip replacement (THR) is aseptic loosening of femoral component which is primarily due to changes of post-operative stress distribution pattern with respect to intact femur. Stress shielding of the femur is known to be a principal factor in aseptic loosening of hip replacements. Many designers show that a stiff stem shields the surrounding bone from mechanical loading causing stress shielding. Others show that reducing stem stiffness promotes higher proximal interface shear stress which increases the risk of proximal interface failure. Therefore, the task of this investigation is to solve these conflicting problems appeared in the cemented total hip replacement. The finite element method and optimization technique are used in order to find the optimal stem material which gives the optimal available stress distribution between the proximal medial femoral bone and the cement mantle interfaces. The stem is designed using the concept of functionally graded material (FGM) instead of using the conventional most common used stem material. The results showed that there are four feasible solutions from the optimization runs. The best of these designs is to use a cemented stem graded from titanium at the upper stem layer to collagen at the lower stem layer. This new cemented stem design completely eliminates the stress shielding problem at the proximal medial femoral region. The stress shielding using the cemented functionally graded stem is reduced by 98% compared to titanium stem. PMID:24840196

  12. Bond strength analysis of the bone cement- stem interface of hip arthroplasties

    Institute of Scientific and Technical Information of China (English)

    Lan-Feng Zhang; Shi-Rong Ge; Hong-Tao Liu; Kai-Jin Guo; Shu-Yang Han; Juan-Yan Qi

    2014-01-01

    Objective:To study and establish the preliminary linear and modified models for the interface shear mechanics performance between implant and bone cement and to explore its damage significance.Method:The loosening research between artificial hip joint prosthesis stem and bone cement interface performance can be evaluated by the push-in test.Based on the debonding performance test, the analytical expressions of the average load and displacement from the debonding failure and splitting failure process were deduced and determined.The correlations of the expressions of the average load-displacement and statistical experimental data were analyzed.Results:It demonstrated that the interface debonding failure mechanical model could be characterized as interface bond strength mechanical performance.Based on analysis of models and experimental data by the three statistical analysis methods, the results indicated the modified model could be better represented by the interfacial debonding strength properties. The bond stressτand relative slidings distribution along the embedment regional were coupling affected by both pressure arch effect and shear lag effect in bone cement.Two stress peaks of implant have been found at the distance from0.175La loading tip to0.325Lafree tip, which also verified the early loosening clinical reports for the proximal and latter region.As the bone cement arch effect, the bond stress peak tend to move to the free tip when the debonding failure would be changed into the splitting failure, which presents a preliminary study on the mechanism of early debonding failurefor the stem-cement interface.Conclusions:Functional models of the stem-bone cement interfacial debonding failure are developed to analyze the relevant mechanism.The different locational titanium alloy stress, and the interfacial bond stress and the relative slides are evaluated to acquire a guide of the different positions of interfacial damage.The coupling effect which is original from

  13. Similar effect of stem geometry on radiological changes with 2 types of cemented straight stem.

    Science.gov (United States)

    Clauss, Martin; Bolliger, Lilianna; Brandenberger, Daniel; Ochsner, Peter E; Ilchmann, Thomas

    2016-04-01

    Background and purpose - There are 2 basic principles in cemented stem fixation: shape-closed and force-closed. We investigated 2 shape-closed straight stems, the Müller (MSS) and the Virtec (VSS), which differ only in geometrical cross section, to determine whether the difference in stem shape would affect the radiological results or long-term survival. Patients and methods - We included 711 hips (in 646 patients) that were operated on between July 1996 and July 2003. Patients randomly received either an MSS (n = 356) or a VSS (n = 355) and were followed prospectively. Radiographs taken at a follow-up of > 10 years were analyzed for osteolysis. Kaplan-Meier (KM) survival analysis was performed using various endpoints. We also performed Cox regression analysis to identify risk factors for aseptic loosening and osteolysis of the stem. Results - After 10 years, KM survival with "revision of any component for any reason" was 92% (95% CI: 88-95) for the MSS and 95% (CI: 92-97) for the VSS (p = 0.1). With "revision for aseptic loosening of the stem" as the endpoint, KM survival was 96% (CI: 9-98) for the MSS and 98% (CI: 97-100) for the VSS (p = 0.2). Cox regression showed that none of the risk factors analyzed were independent regarding aseptic loosening of the stem or regarding osteolysis. Interpretation - The MSS and the VSS showed excellent survival for aseptic loosening after 10 years. For the 2 different stem designs, we did not find any independent risk factors for aseptic loosening or development of osteolysis. PMID:26471977

  14. Mid-term study of bone remodeling after femoral cemented stem implantation: comparison between DXA and finite element simulation.

    Science.gov (United States)

    Herrera, Antonio; Rebollo, Sarai; Ibarz, Elena; Mateo, Jesús; Gabarre, Sergio; Gracia, Luis

    2014-01-01

    This five-year prospective study was designed to investigate periprosthetic bone remodeling associated with two cemented stem models, ABG-II (Stryker) and VerSys (Zimmer), randomly implanted in patients older than 75 years. The sample consisted of 64 cases (32, ABG-II; 32, VerSys). Inclusion criterion was diagnosis of osteoarthritis recommended for cemented total hip arthroplasty. Besides clinical study, Finite Element (FE) simulation was used to analyze biomechanical changes caused by hip arthroplasty. Bone Mineral Density (BMD) measurements showed a progressive increase in bone mass throughout the entire follow-up period for both stems, well correlated with FE results except in Gruen zones 4, 5, 6 for ABG-II and in zones 4, 5 for VerSys, denoting that remodeling in those zones does not depend on mechanical factors but rather on biological or physiological ones. PMID:23725926

  15. Contact damage failure analyses of fretting wear behavior of the metal stem titanium alloy-bone cement interface.

    Science.gov (United States)

    Zhang, Lanfeng; Ge, Shirong; Liu, Hongtao; Wang, Qingliang; Wang, Liping; Xian, Cory J

    2015-11-01

    Although cemented titanium alloy is not favored currently in the Western world for its poor clinical and radiography outcomes, its lower modulus of elasticity and good biocompatibility are instrumental for its ability supporting and transforming physical load, and it is more suitable for usage in Chinese and Japanese populations due to their lower body weights and unique femoral characteristics. Through various friction tests of different cycles, loads and conditions and by examining fretting hysteresis loops, fatigue process curves and wear surfaces, the current study investigated fretting wear characteristics and wear mechanism of titanium alloy stem-bone cement interface. It was found that the combination of loads and displacement affected the wear quantity. Friction coefficient, which was in an inverse relationship to load under the same amplitude, was proportional to amplitudes under the same load. Additionally, calf serum was found to both lubricate and erode the wear interface. Moreover, cement fatigue contact areas appeared black/oxidative in dry and gruel in 25% calf serum. Fatigue scratches were detected within contact areas, and wear scars were found on cement and titanium surfaces, which were concave-shaped and ring concave/ convex-shaped, respectively. The coupling of thermoplastic effect and minimal torque damage has been proposed to be the major reason of contact damage. These data will be important for further studies analyzing metal-cement interface failure performance and solving interface friction and wear debris production issues. PMID:26241891

  16. Use of a genetic algorithm for multiobjective design optimization of the femoral stem of a cemented total hip arthroplasty.

    Science.gov (United States)

    Ishida, Toshimasa; Nishimura, Ikuya; Tanino, Hiromasa; Higa, Masaru; Ito, Hiroshi; Mitamura, Yoshinori

    2011-04-01

    There are many designs of the femoral stem of a cemented total hip arthroplasty, and mechanical failure of the stem is caused by several factors related to the cement, such as failure of the cement. Optimization of the shape of the stem, especially multiobjective optimization, is required to solve these design problems because a cement fracture is caused by multiple factors. The objective of this study was to determine a stem geometry considering multiple factors at the same time. A three-dimensional finite element model of the proximal femur was developed from a composite femur. A total of four objective functions--two objective functions, the largest maximum principal stress of proximal and distal sections in the cement mantle, for each of the two boundary conditions, walking and stair climbing--were used. The neighborhood cultivation genetic algorithm was introduced to minimize these objective functions. The results showed that the geometry that leads to a decrease in the proximal cement stress and the geometry that leads to a decrease in the distal cement stress were not the same. However, the results of the walking and the stair climbing conditions matched. Five dominant stem designs were considered to be the Pareto solution, and one design was identified as the "better design" for all objective functions. It was shown that multiobjective optimization using a genetic algorithm may be used for optimizing the shape of the femoral stem in order to avoid cement fracture. PMID:21332564

  17. Induced Pluripotent Stem Cell-derived Mesenchymal Stem Cell Seeding on Biofunctionalized Calcium Phosphate Cements

    Institute of Scientific and Technical Information of China (English)

    WahWah TheinHan; Jun Liu; Minghui Tang; Wenchuan Chen; Linzhao Cheng; Hockin H. K. Xu

    2013-01-01

    Induced pluripotent stem cells (iPSCs) have great potential due to their proliferation and differentiation capability. The objectives of this study were to generate iPSC-derived mesenchymal stem cells (iPSC-MSCs), and investigate iPSC-MSC proliferation and osteogenic differentiation on calcium phosphate cement (CPC) containing biofunctional agents for the first time. Human iPSCs were derived from marrow CD34+ cells which were reprogrammed by a single episomal vector. iPSCs were cultured to form embryoid bodies (EBs), and MSCs migrated out of EBs. Five biofunctional agents were incorporated into CPC:RGD (Arg-Gly-Asp) peptides, fibronectin (Fn), fibronectin-like engineered polymer protein (FEPP), extracellular matrix Geltrex, and platelet concentrate. iPSC-MSCs were seeded on five biofunctionalized CPCs:CPC-RGD, CPC-Fn, CPC-FEPP, CPC-Geltrex, and CPC-Platelets. iPSC-MSCs on biofunctional CPCs had enhanced proliferation, actin fiber expression, osteogenic differentiation and mineralization, compared to control. Cell proliferation was greatly increased on biofunctional CPCs. iPSC-MSCs underwent osteogenic differentiation with increased alkaline phosphatase, Runx2 and collagen-I expressions. Mineral synthesis by iPSC-MSCs on CPC-Platelets was 3-fold that of CPC control. In conclusion, iPSCs showed high potential for bone engineering. iPSC-MSCs on biofunctionalized CPCs had cell proliferation and bone mineralization that were much better than traditional CPC. iPSC-MSC-CPC constructs are promising to promote bone regeneration in craniofacial/orthopedic repairs.

  18. Total Hip Arthroplasty Using a Polished Tapered Cemented Stem in Hereditary Multiple Exostosis

    Directory of Open Access Journals (Sweden)

    Akio Kanda

    2016-01-01

    Full Text Available A 61-year-old Japanese man underwent right total hip arthroplasty for hereditary multiple exostosis. At first presentation, he had suffered from coxalgia for a long time. On radiographic images, there was a gigantic femoral head, increased shaft angle, and large diameter of the femoral neck. He had also developed coxarthrosis and severe pain of the hip joint. The transformation of the proximal femur bone causes difficulty in setting a cementless total hip prosthesis. Therefore, total hip arthroplasty using a cemented polished tapered stem was performed via a direct lateral approach. Using a cemented polished tapered stem allowed us to deal with the femoral bone transformation and bone substance defectiveness due to exostosis and also minimized the invasiveness of the operation.

  19. Effects of Prosthesis Stem Tapers on Stress Distribution of Cemented Hip Arthroplasty

    International Nuclear Information System (INIS)

    Aseptic loosening effects are critical issues in encouraging long term stability of cemented hip arthroplasty. Stress shielding is believed to be an important factor that contributes to the aseptic loosening problems. The numerous changes in the prosthesis stem design are intended to minimize the stress shielding and aseptic loosening problems and to improve the long term performance of the implants. In this study, the stress distribution in cemented hip arthroplasty is established using finite element method. The taper of the prosthesis is designed to be 3 deg. at anterior/posterior, 3 deg. at medial/lateral and 10 deg. from wide lateral to narrow medial. Major muscle loads and contact forces are simulated for walking (toe-off phase) and stair climbing load cases. Effects of prosthesis stem tapers on the resulting stress distribution are investigated. Results show that compressive stress dominates in the medial plane while tensile stress in the lateral plane of the femur. The corresponding stress levels of intact femur for walking and stair-climbing load cases are 22 and 29 MPa, respectively. The magnitude of Tresca stress for the THA femur in stair-climbing load case remains higher in the region of 85 MPa while the walking load case induces around 40 MPa. The stress range in the straight and single taper stem prosthesis is lower than 260 MPa, while localized Tresca stress is in the order of the yield strength of Ti-6Al-4V alloy for double and triple taper stem design.

  20. Clinical application of stem cells: An update 2015

    OpenAIRE

    Van, Phuc Pham

    2016-01-01

    Stem cell transplantation has the long history of more than 50 years from the first bone marrow transplantation in 1957. From the 2000s, clinical applications of stem cells significantly increased with more diseases and more patients treated with stem cells. Both autologous stem cells and allogenic stem cells as well as adult stem cells and induced pluripotent stem cells (iPSCs), and both in vitro non-expanded stem cells and in vitro expanded stem cells were clinically applied. For adult stem...

  1. Representations of stem cell clinics on Twitter.

    Science.gov (United States)

    Kamenova, Kalina; Reshef, Amir; Caulfield, Timothy

    2014-12-01

    The practice of travelling abroad to receive unproven and unregulated stem cell treatments has become an increasingly problematic global phenomenon known as 'stem cell tourism'. In this paper, we examine representations of nine major clinics and providers of such treatments on the microblogging network Twitter. We collected and conducted a content analysis of Twitter posts (n = 363) by these establishments and by other users mentioning them, focusing specifically on marketing claims about treatment procedures and outcomes, discussions of safety and efficacy of stem cell transplants, and specific representations of patients' experiences. Our analysis has shown that there were explicit claims or suggestions of benefits associated with unproven stem cell treatments in approximately one third of the tweets and that patients' experiences, whenever referenced, were presented as invariably positive and as testimonials about the efficacy of stem cell transplants. Furthermore, the results indicated that the tone of most tweets (60.2 %) was overwhelmingly positive and there were rarely critical discussions about significant health risks associated with unproven stem cell therapies. When placed in the context of past research on the problems associated with the marketing of unproven stem cell therapies, this analysis of representations on Twitter suggests that discussions in social media have also remained largely uncritical of the stem cell tourism phenomenon, with inaccurate representations of risks and benefits for patients. PMID:24970380

  2. Clinical translation of human neural stem cells.

    Science.gov (United States)

    Tsukamoto, Ann; Uchida, Nobuko; Capela, Alexandra; Gorba, Thorsten; Huhn, Stephen

    2013-01-01

    Human neural stem cell transplants have potential as therapeutic candidates to treat a vast number of disorders of the central nervous system (CNS). StemCells, Inc. has purified human neural stem cells and developed culture conditions for expansion and banking that preserve their unique biological properties. The biological activity of these human central nervous system stem cells (HuCNS-SC®) has been analyzed extensively in vitro and in vivo. When formulated for transplantation, the expanded and cryopreserved banked cells maintain their stem cell phenotype, self-renew and generate mature oligodendrocytes, neurons and astrocytes, cells normally found in the CNS. In this overview, the rationale and supporting data for pursuing neuroprotective strategies and clinical translation in the three components of the CNS (brain, spinal cord and eye) are described. A phase I trial for a rare myelin disorder and phase I/II trial for spinal cord injury are providing intriguing data relevant to the biological properties of neural stem cells, and the early clinical outcomes compel further development. PMID:23987648

  3. Clinical grade adult stem cell banking

    OpenAIRE

    Thirumala, Sreedhar; Goebel, W. Scott; Woods, Erik J

    2009-01-01

    There has been a great deal of scientific interest recently generated by the potential therapeutic applications of adult stem cells in human care but there are several challenges regarding quality and safety in clinical applications and a number of these challenges relate to the processing and banking of these cells ex-vivo. As the number of clinical trials and the variety of adult cells used in regenerative therapy increases, safety remains a primary concern. This has inspired many nations t...

  4. Changes in bone mineral density (BMD) around the cemented Exeter stem: a prospective study in 18 women with 5 years follow-up

    DEFF Research Database (Denmark)

    Damborg, Frank; Nissen, Nis; Jørgensen, Hans R I;

    2008-01-01

    BACKGROUND AND PURPOSE: THA changes the pattern of strain distribution in the proximal femur. We quantified the changes in BMD for 5 years after insertion of the cemented Exeter stem in women. METHODS: 18 women aged 55-79 years, undergoing unilateral THA with the cemented Exeter stem, were included...

  5. A modified PMMA cement (Sub-cement) for accelerated fatigue testing of cemented implant constructs using cadaveric bone.

    Science.gov (United States)

    Race, Amos; Miller, Mark A; Mann, Kenneth A

    2008-10-20

    Pre-clinical screening of cemented implant systems could be improved by modeling the longer-term response of the implant/cement/bone construct to cyclic loading. We formulated bone cement with degraded fatigue fracture properties (Sub-cement) such that long-term fatigue could be simulated in short-term cadaver tests. Sub-cement was made by adding a chain-transfer agent to standard polymethylmethacrylate (PMMA) cement. This reduced the molecular weight of the inter-bead matrix without changing reaction-rate or handling characteristics. Static mechanical properties were approximately equivalent to normal cement. Over a physiologically reasonable range of stress-intensity factor, fatigue crack propagation rates for Sub-cement were higher by a factor of 25+/-19. When tested in a simplified 2 1/2-D physical model of a stem-cement-bone system, crack growth from the stem was accelerated by a factor of 100. Sub-cement accelerated both crack initiation and growth rate. Sub-cement is now being evaluated in full stem/cement/femur models. PMID:18774136

  6. Correlation between clinical performance and degree of conversion of resin cements: a literature review

    Directory of Open Access Journals (Sweden)

    Grace DE SOUZA

    2015-08-01

    Full Text Available AbstractResin-based cements have been frequently employed in clinical practice to lute indirect restorations. However, there are numerous factors that may compromise the clinical performance of those cements. The aim of this literature review is to present and discuss some of the clinical factors that may affect the performance of current resin-based luting systems. Resin cements may have three different curing mechanisms: chemical curing, photo curing or a combination of both. Chemically cured systems are recommended to be used under opaque or thick restorations, due to the reduced access of the light. Photo-cured cements are mainly indicated for translucent veneers, due to the possibility of light transmission through the restoration. Dual-cured are more versatile systems and, theoretically, can be used in either situation, since the presence of both curing mechanisms might guarantee a high degree of conversion (DC under every condition. However, it has been demonstrated that clinical procedures and characteristics of the materials may have many different implications in the DC of currently available resin cements, affecting their mechanical properties, bond strength to the substrate and the esthetic results of the restoration. Factors such as curing mechanism, choice of adhesive system, indirect restorative material and light-curing device may affect the degree of conversion of the cement and, therefore, have an effect on the clinical performance of resin-based cements. Specific measures are to be taken to ensure a higher DC of the luting system to be used.

  7. Correlation between clinical performance and degree of conversion of resin cements: a literature review

    Science.gov (United States)

    DE SOUZA, Grace; BRAGA, Roberto Ruggiero; CESAR, Paulo Francisco; LOPES, Guilherme Carpena

    2015-01-01

    Resin-based cements have been frequently employed in clinical practice to lute indirect restorations. However, there are numerous factors that may compromise the clinical performance of those cements. The aim of this literature review is to present and discuss some of the clinical factors that may affect the performance of current resin-based luting systems. Resin cements may have three different curing mechanisms: chemical curing, photo curing or a combination of both. Chemically cured systems are recommended to be used under opaque or thick restorations, due to the reduced access of the light. Photo-cured cements are mainly indicated for translucent veneers, due to the possibility of light transmission through the restoration. Dual-cured are more versatile systems and, theoretically, can be used in either situation, since the presence of both curing mechanisms might guarantee a high degree of conversion (DC) under every condition. However, it has been demonstrated that clinical procedures and characteristics of the materials may have many different implications in the DC of currently available resin cements, affecting their mechanical properties, bond strength to the substrate and the esthetic results of the restoration. Factors such as curing mechanism, choice of adhesive system, indirect restorative material and light-curing device may affect the degree of conversion of the cement and, therefore, have an effect on the clinical performance of resin-based cements. Specific measures are to be taken to ensure a higher DC of the luting system to be used. PMID:26398507

  8. A Review of Glass-Ionomer Cements for Clinical Dentistry.

    Science.gov (United States)

    Sidhu, Sharanbir K; Nicholson, John W

    2016-01-01

    This article is an updated review of the published literature on glass-ionomer cements and covers their structure, properties and clinical uses within dentistry, with an emphasis on findings from the last five years or so. Glass-ionomers are shown to set by an acid-base reaction within 2-3 min and to form hard, reasonably strong materials with acceptable appearance. They release fluoride and are bioactive, so that they gradually develop a strong, durable interfacial ion-exchange layer at the interface with the tooth, which is responsible for their adhesion. Modified forms of glass-ionomers, namely resin-modified glass-ionomers and glass carbomer, are also described and their properties and applications covered. Physical properties of the resin-modified glass-ionomers are shown to be good, and comparable with those of conventional glass-ionomers, but biocompatibility is somewhat compromised by the presence of the resin component, 2 hydroxyethyl methacrylate. Properties of glass carbomer appear to be slightly inferior to those of the best modern conventional glass-ionomers, and there is not yet sufficient information to determine how their bioactivity compares, although they have been formulated to enhance this particular feature. PMID:27367737

  9. Substrates for clinical applicability of stem cells

    Institute of Scientific and Technical Information of China (English)

    Sanjar Enam; Sha Jin

    2015-01-01

    The capability of human pluripotent stem cells (hPSCs)to differentiate into a variety of cells in the human bodyholds great promise for regenerative medicine. Manysubstrates exist on which hPSCs can be self-renewed,maintained and expanded to further the goal of clinicalapplication of stem cells. In this review, we highlightnumerous extracellular matrix proteins, peptide andpolymer based substrates, scaffolds and hydrogelsthat have been pioneered. We discuss their benefitsand shortcomings and offer future directions as well asemphasize commercially available synthetic peptidesas a type of substrate that can bring the benefits ofregenerative medicine to clinical settings.

  10. Radioactive bone cement for the treatment of spinal metastases: a dosimetric analysis of simulated clinical scenarios

    Science.gov (United States)

    Kaneko, T. S.; Sehgal, V.; Skinner, H. B.; Al-Ghazi, M. S. A. L.; Ramsinghani, N. S.; Marquez Miranda, M.; Keyak, J. H.

    2012-07-01

    Vertebral metastases are a common manifestation of many cancers, potentially leading to vertebral collapse and neurological complications. Conventional treatment often involves percutaneous vertebroplasty/kyphoplasty followed by external beam radiation therapy. As a more convenient alternative, we have introduced radioactive bone cement, i.e. bone cement incorporating a radionuclide. In this study, we used a previously developed Monte Carlo radiation transport modeling method to evaluate dose distributions from phosphorus-32 radioactive cement in simulated clinical scenarios. Isodose curves were generally concentric about the surface of bone cement injected into cadaveric vertebrae, indicating that dose distributions are relatively predictable, thus facilitating treatment planning (cement formulation and dosimetry method are patent pending). Model results indicated that a therapeutic dose could be delivered to tumor/bone within ∼4 mm of the cement surface while maintaining a safe dose to radiosensitive tissue beyond this distance. This therapeutic range should be sufficient to treat target volumes within the vertebral body when tumor ablation or other techniques are used to create a cavity into which the radioactive cement can be injected. With further development, treating spinal metastases with radioactive bone cement may become a clinically useful and convenient alternative to the conventional two-step approach of percutaneous strength restoration followed by radiotherapy.

  11. Access to Abutment Screw in Cement Retained Restorations: A Clinical Tip

    Science.gov (United States)

    Harianawala, Husain; Kantharia, Nidhi; Sethi, Tania; Jambhekar, Shantanu

    2015-01-01

    Abutment screw loosening has been reported to be the most common prosthetic complications occurring in screw retained as well as cement retained implant restorations. Different methods to treat this issue have been reported in the literature so far; however these have their own short-comings. Retrievability of an implant restoration intact becomes a clinical challenge when the restoration is cement retained especially with an angulated abutment. This technique is aimed at accurately determining the position of the abutment screw in 3 dimensional relationships using a vacuum formed clear stent. This technique can be used as a viable protocol for management of screw loosening in cement retained implant restorations. PMID:25859535

  12. In vitro assessment of Function Graded (FG artificial Hip joint stem in terms of bone/cement stresses: 3D Finite Element (FE study

    Directory of Open Access Journals (Sweden)

    Al-Jassir Fawzi F

    2013-01-01

    Full Text Available Abstract Background Stress shielding in the cemented hip prosthesis occurs due to the mismatching in the mechanical properties of metallic stem and bone. This mismatching in properties is considered as one of the main reasons for implant loosening. Therefore, a new stem material in orthopedic surgery is still required. In the present study, 3D finite element modeling is used for evaluating the artificial hip joint stem that is made of Function Graded (FG material in terms of joint stress distributions and stem length. Method 3D finite element models of different stems made of two types of FG materials and traditional stems made of Cobalt Chromium alloy (CoCrMo and Titanium alloy (Ti were developed using the ANSYS Code. The effects on the total artificial hip joint stresses (Shear stress and Von Mises stresses at bone cement, Von Mises stresses at bone and stem due to using the proposed FG materials stems were investigated. The effects on the total artificial hip joint system stresses due to using different stem lengths were investigated. Results Using FG stem (with low stiffness at stem distal end and high stiffness at its proximal end resulted in a significant reduction in shear stress at the bone cement/stem interface. Also, the Von Mises stresses at the bone cement and stem decrease significantly when using FG material instead of CoCrMo and Ti alloy. The stresses’ distribution along the bone cement length when using FG material was found to be more uniform along the whole bone cement compared with other stem materials. These more uniform stresses will help in the reduction of the artificial hip joint loosening rate and improve its short and long term performance. Conclusion FE results showed that using FG stem increases the resultant stresses at the femur bone (reduces stress shielding compared to metallic stem. The results showed that the stem length has significant effects on the resultant shear and Von Mises stresses at bone, stem and

  13. Mesenchymal stem cells: characteristics and clinical applications.

    Directory of Open Access Journals (Sweden)

    Sylwia Bobis

    2007-01-01

    Full Text Available Mesenchymal stem cells (MSCs are bone marrow populating cells, different from hematopoietic stem cells, which possess an extensive proliferative potential and ability to differentiate into various cell types, including: osteocytes, adipocytes, chondrocytes, myocytes, cardiomyocytes and neurons. MSCs play a key role in the maintenance of bone marrow homeostasis and regulate the maturation of both hematopoietic and non-hematopoietic cells. The cells are characterized by the expression of numerous surface antigens, but none of them appears to be exclusively expressed on MSCs. Apart from bone marrow, MSCs are located in other tissues, like: adipose tissue, peripheral blood, cord blood, liver and fetal tissues. MSCs have been shown to be powerful tools in gene therapies, and can be effectively transduced with viral vectors containing a therapeutic gene, as well as with cDNA for specific proteins, expression of which is desired in a patient. Due to such characteristics, the number of clinical trials based on the use of MSCs increase. These cells have been successfully employed in graft versus host disease (GvHD treatment, heart regeneration after infarct, cartilage and bone repair, skin wounds healing, neuronal regeneration and many others. Of special importance is their use in the treatment of osteogenesis imperfecta (OI, which appeared to be the only reasonable therapeutic strategy. MSCs seem to represent a future powerful tool in regenerative medicine, therefore they are particularly important in medical research.

  14. Factors influencing success of cement versus screw-retained implant restorations: a clinical review

    Directory of Open Access Journals (Sweden)

    Ahmad Manawar

    2012-10-01

    Full Text Available Aim: As more and more dental practitioners are focusing on implant-supported fixed restorations, some clinicians favor the use of cement retained restorations while others consider screw retained prosthesis to be the best choice. Discussion: In screw-retained restorations, the fastening screw provides a solid joint between the restoration and the implant abutment, while in cement-retained prostheses the restorative screw is eliminated to enhance esthetics, occlusal stability, and passive fit of the restorations. The factors that influence the type of fixation of the prostheses to the implants like passivity of the framework, ease of fabrication, occlusion, esthetics, accessibility, retention and retrievability are discussed in this article with scientific studies demonstrating superior outcomes of one technique over another. Screwretained implant restorations have an advantage of predictable retention, retrievability and lack of potentially retained subgingival cement. However, a few disadvantages exist such as precise placement of the implant for optimal and esthetic location of the screw access hole and obtaining passive fit. On the other hand, cement retained restorations eliminate unesthetic screw access holes, have passive fit of castings, reduced complexity of clinical and lab procedures, enhanced esthetics, reduced cost factors and non disrupted morphology of the occlusal table. Conclusion: This article compares the advantages, potential disadvantages and limitations of screw and cement retained restorations and their specific implications in the most common clinical situation.

  15. Mesenchymal stem cells: from experiment to clinic

    Directory of Open Access Journals (Sweden)

    Otto William R

    2011-09-01

    Full Text Available Abstract There is currently much interest in adult mesenchymal stem cells (MSCs and their ability to differentiate into other cell types, and to partake in the anatomy and physiology of remote organs. It is now clear these cells may be purified from several organs in the body besides bone marrow. MSCs take part in wound healing by contributing to myofibroblast and possibly fibroblast populations, and may be involved in epithelial tissue regeneration in certain organs, although this remains more controversial. In this review, we examine the ability of MSCs to modulate liver, kidney, heart and intestinal repair, and we update their opposing qualities of being less immunogenic and therefore tolerated in a transplant situation, yet being able to contribute to xenograft models of human tumour formation in other contexts. However, such observations have not been replicated in the clinic. Recent studies showing the clinical safety of MSC in several pathologies are discussed. The possible opposing powers of MSC need careful understanding and control if their clinical potential is to be realised with long-term safety for patients.

  16. Maxillary cement retained implant supported monolithic zirconia prosthesis in a full mouth rehabilitation: a clinical report

    OpenAIRE

    Sadid-Zadeh, Ramtin; Liu, Perng-Ru; Aponte-Wesson, Ruth; O'Neal, Sandra J

    2013-01-01

    This clinical report presents the reconstruction of a maxillary arch with a cement retained implant supported fixed prosthesis using a monolithic zirconia generated by CAD/CAM system on eight osseointegrated implants. The prosthesis was copy milled from an interim prosthesis minimizing occlusal adjustments on the definitive prosthesis at the time of delivery. Monolithic zirconia provides high esthetics and reduces the number of metal alloys used in the oral cavity.

  17. Stem cells in clinical practice: applications and warnings

    Directory of Open Access Journals (Sweden)

    Palmieri Beniamino

    2011-01-01

    Full Text Available Abstract Stem cells are a relevant source of information about cellular differentiation, molecular processes and tissue homeostasis, but also one of the most putative biological tools to treat degenerative diseases. This review focuses on human stem cells clinical and experimental applications. Our aim is to take a correct view of the available stem cell subtypes and their rational use in the medical area, with a specific focus on their therapeutic benefits and side effects. We have reviewed the main clinical trials dividing them basing on their clinical applications, and taking into account the ethical issue associated with the stem cell therapy. Methods We have searched Pubmed/Medline for clinical trials, involving the use of human stem cells, using the key words "stem cells" combined with the key words "transplantation", "pathology", "guidelines", "properties" and "risks". All the relevant clinical trials have been included. The results have been divided into different categories, basing on the way stem cells have been employed in different pathological conditions.

  18. Restoration of non-carious cervical lesions with ceramic inlays: A possible model for clinical testing of adhesive cements

    OpenAIRE

    Michal Staninec; Tsuji, Grant H.

    2012-01-01

    Introduction: There are many luting cements coming to market which claim to be adhesive, but there is no clinical protocol currently for testing these claims. There is a standardized protocol for testing direct restorations bonded to dentin and it is used extensively. Case Report: We describe a clinical procedure for restoring a non-carious cervical lesion (NCCL) with a ceramic inlay using Computer-Aided Design and Computer-Aided Manufacturing (CAD-CAM) technology and an adhesive resin cement...

  19. Clinical perspectives of cancer stem cell research in radiation oncology

    International Nuclear Information System (INIS)

    Radiotherapy has a proven potential to eradicate cancer stem cells which is reflected by its curative potential in many cancer types. Considerable progress has been made in identification and biological characterisation of cancer stem cells during the past years. Recent biological findings indicate significant inter- and intratumoural and functional heterogeneity of cancer stem cells and lead to more complex models which have potential implications for radiobiology and radiotherapy. Clinical evidence is emerging that biomarkers of cancer stem cells may be prognostic for the outcome of radiotherapy in some tumour entities. Perspectives of cancer stem cell based research for radiotherapy reviewed here include their radioresistance compared to the mass of non-cancer stem cells which form the bulk of all tumour cells, implications for image- and non-image based predictive bio-assays of the outcome of radiotherapy and a combination of novel systemic treatments with radiotherapy

  20. Human tooth germ stem cell response to calcium-silicate based endodontic cements

    Directory of Open Access Journals (Sweden)

    Esra Pamukcu Guven

    2013-07-01

    Full Text Available OBJECTIVE: The aim of this study was to compare the cytotoxic effects of endodontic cements on human tooth germ stem cells (hTGSCs. MTA Fillapex, a mineral trioxide aggregate (MTA-based, salicylate resin containing root canal sealer, was compared with iRoot SP, a bioceramic sealer, and AH Plus Jet, an epoxy resin-based root canal sealer. MATERIAL AND METHODS: To evaluate cytotoxicity, all materials were packed into Teflon rings (4 mmµ3 mm and co-cultured with hTGSCs with the aid of 24-well Transwell permeable supports, which had a pore size of 0.4 µm. Coverslips were coated with MTA Fillapex, iRoot SP and AH Plus Jet and each coverslip was placed onto the bottom of one well of a six-well plate for scanning electron microscopy (SEM analysis. Before the cytotoxicity and SEM analysis, all samples were stored at 37ºC and at 95% humidity and 5% CO2 for 24 hours to set. The cellular viability was analyzed using MTS test (3-(4,5-dimethyl-thiazol-2-yl-5-(3-carboxy-methoxy-phenyl-2-(4-sulfo-phenyl-2H-tetrazolium. The cytotoxic effects and SEM visualization of the tested materials were analyzed at 24-hour, 72-hour, one-week and two-week periods. RESULTS: On the 1st day, only MTA Fillapex caused cytotoxicity compared to negative control (NC group (p0.05. After 14 days of incubation with the test materials, MTA Fillapex exhibited significantly higher cytotoxicity compared with iRoot SP, AH Plus Jet and the NC group (P<0.008. In the SEM analysis, the highest levels of cell attachment were observed for iRoot SP and the control group. After 24 hours, MTA Fillapex reduced the number of cells attached to the surface. CONCLUSIONS: Within the limitations of this study, sealers exerted different cytotoxic effects on hTGSCs. Although all materials have exerted cellular toxicity, iRoot SP and AH Plus Jet may promote better attachment to hTGSCs.

  1. Substantially higher prevalence of postoperative peri­prosthetic fractures in octogenarians with hip fractures operated with a cemented, polished tapered stem rather than an anatomic stem

    Science.gov (United States)

    Mukka, Sebastian; Mellner, Carl; Knutsson, Björn; Sayed-Noor, Arkan; Sköldenberg, Olof

    2016-01-01

    Background and purpose Recent studies have demonstrated a high incidence of postoperative periprosthetic femoral fracture (PPF) in elderly patients treated with 2 commonly used cemented, polished tapered stems. We compared the prevalence and incidence rate of PPF in a consecutive cohort of octagenerians with femoral neck fractures (FNFs) treated with either a collarless, polished tapered (CPT) stem or an anatomic matte stem (Lubinus SP2). Patients and methods In a multicenter, prospective cohort study, we included 979 hips in patients aged 80 years and above (72% females, median age 86 (80–102) years) with a femoral neck fracture as indication for surgery. 69% of the patients were classified as ASA class 3 or 4. Hip-related complications and repeat surgery were assessed at a median follow-up of 20 (0–24) months postoperatively. Results 22 hips (2.2%) sustained a PPF at a median of 7 (0–22) months postoperatively; 14 (64%) were Vancouver B2 fractures. 7 of the 22 surgically treated fractures required revision surgery, mainly due to deep infection. The cumulative incidence of PPFs was 3.8% in the CPT group, as compared with 0.2% in the SP2 group (p < 0.001). The risk ratio (RR) was 16 (95% CI: 2–120) using the SP2 group as denominator. Interpretation The CPT stem was associated with a higher risk of PPF than the SP2 stem. We suggest that the tapered CPT stem should not be used for the treatment of femoral neck fractures in patients over 80 years. PMID:27045318

  2. The mechanical effect of the existing cement mantle on the in-cement femoral revision.

    LENUS (Irish Health Repository)

    Keeling, Parnell

    2012-08-01

    Cement-in-cement revision hip arthroplasty is an increasingly popular technique to replace a loose femoral stem which retains much of the original cement mantle. However, some concern exists regarding the retention of the existing fatigued and aged cement in such cement-in-cement revisions. This study investigates whether leaving an existing fatigued and aged cement mantle degrades the mechanical performance of a cement-in-cement revision construct.

  3. Cardiac Stem Cells: Biology and Clinical Applications

    OpenAIRE

    Goichberg, Polina; Chang, Jerway; Liao, Ronglih; Leri, Annarosa

    2014-01-01

    Significance: Heart disease is the primary cause of death in the industrialized world. Cardiac failure is dictated by an uncompensated reduction in the number of viable and fully functional cardiomyocytes. While current pharmacological therapies alleviate the symptoms associated with cardiac deterioration, heart transplantation remains the only therapy for advanced heart failure. Therefore, there is a pressing need for novel therapeutic modalities. Cell-based therapies involving cardiac stem ...

  4. Adult Stromal (Skeletal, Mesenchymal) Stem Cells: Advances Towards Clinical Applications

    DEFF Research Database (Denmark)

    Kermani, Abbas Jafari; Harkness, Linda; Zaher, Walid;

    2014-01-01

    are under intensive investigation worldwide. Several challenges with regard to the proper source of clinical-grade MSC and the efficacy of MSC-based treatment strategies need to be addressed before MSC can be routinely used in the clinic. Here, we discuss three areas that can potentially facilitate...... the translation of MSC into clinic: Generation of MSC-like cells from human pluripotent stem cells, strategies to enhance homing of MSC to injured tissues, and targeting of MSC in vivo....

  5. Canine pluripotent stem cells: Are they ready for clinical applications?

    Directory of Open Access Journals (Sweden)

    Dean Harvey Betts

    2015-10-01

    Full Text Available The derivation of canine embryonic stem cells and generation of canine induced pluripotent stem cells are significant achievements that have unlocked the potential for developing novel cell-based disease models, drug discovery platforms and transplantation therapies in the dog. A progression from concept to cure in this clinically relevant companion animal will not only help our canine patients but also help advance human regenerative medicine. Nevertheless, many issues remain to be resolved before pluripotent cells can be used clinically in a safe and reproducible manner.

  6. Human mesenchymal stem cells: from basic biology to clinical applications

    DEFF Research Database (Denmark)

    Abdallah, B M; Kassem, M

    2008-01-01

    Mesenchymal stem cells (MSC) are a group of clonogenic cells present among the bone marrow stroma and capable of multilineage differentiation into mesoderm-type cells such as osteoblasts, adipocytes and chondrocytes. Due to their ease of isolation and their differentiation potential, MSC are being...... introduced into clinical medicine in variety of applications and through different ways of administration. Here, we discuss approaches for isolation, characterization and directing differentiation of human mesenchymal stem cells (hMSC). An update of the current clinical use of the cells is also provided....

  7. Stem cells: progressions and applications in clinical medicine

    Directory of Open Access Journals (Sweden)

    Ali Hosseini Bereshneh

    2016-05-01

    of them in transferring gene into different cells. Today, this method have had considerable progress in the treatment of many disease. In this review study, some aspect of stem cells like types and characteristic, origin, derivation techniques, storage conditions and differentiation to target tissues, current clinical usage and their therapeutic capabilities will be discussed.

  8. Restoration of non-carious cervical lesions with ceramic inlays: A possible model for clinical testing of adhesive cements

    Directory of Open Access Journals (Sweden)

    Michal Staninec

    2012-01-01

    Full Text Available Introduction: There are many luting cements coming to market which claim to be adhesive, but there is no clinical protocol currently for testing these claims. There is a standardized protocol for testing direct restorations bonded to dentin and it is used extensively. Case Report: We describe a clinical procedure for restoring a non-carious cervical lesion (NCCL with a ceramic inlay using Computer-Aided Design and Computer-Aided Manufacturing (CAD-CAM technology and an adhesive resin cement.The procedure was straightforward and the result was good at one month. Discussion: NCCL′s can be restored with CAD-CAM technology in one appointment. This technique can be used to clinically test adhesion of luting cements to dentin, similarly to the current standard for direct restorations.

  9. Clinical application of mesenchymal stem cells for aseptic bone necrosis

    Directory of Open Access Journals (Sweden)

    Tomoki Aoyama

    2008-11-01

    Full Text Available Since 2007, we had started clinical trial using mesenchymal stem cell (MSCs for the treatment of aseptic bone necrosis as a first clinical trial permitted by Japanese Health, Labour and Welfare Ministry.Aseptic bone necrosis of the femoral head commonly occurs in patients with two to four decades, causing severe musculoskeletal disability. Although its diagnosis is easy with X-ray and MRI, there has been no gold standard invented for treatment of this disease. MSCs represent a stem cell population in adult tissues that can be isolated and expanded in culture, and differentiate into cells with different nature. Combination with β-tri-calcium phosphate and vascularized bone graft, we succeeded to treat bone necrosis of the femoral head.Regenerative medicine using stem cells is hopeful and shed a light on intractable disease. To become widespread, Basic, Translational, Application, and Developmental study is needed.? From an experience of cell therapy using MSCs, we started to research induced pluripotent stem cell (iPS for clinical application.

  10. Mesenchymal stem cells: biological characteristics and potential clinical applications

    DEFF Research Database (Denmark)

    Kassem, Moustapha

    2004-01-01

    Mesenchymal stem cells (MSC) are clonogenic, non-hematpoietic stem cells present in the bone marrow and are able to differentiate into multiple mesoderm-type cell lineages, for example, osteoblasts, chondrocytes, endothelial-cells and also non-mesoderm-type lineages, for example, neuronal...... among the first stem cell types to be introduced in the clinic. Several studies have demonstrated the possible use of MSC in systemic transplantation for systemic diseases, local implantation for local tissue defects, as a vehicle for genes in gene therapy protocols or to generate transplantable tissues......-like cells. Several methods are currently available for isolation of the MSC based on their physical and physico-chemical characteristics, for example, adherence to plastics or other extracellular matrix components. Because of the ease of their isolation and their extensive differentiation potential, MSC are...

  11. Using a porcelain furnace to debond cement-retained implant crown from the abutment after screw fracture: a clinical report.

    Science.gov (United States)

    Saponaro, Paola C; Heshmati, Reza H; Lee, Damian J

    2015-04-01

    When a screw fracture occurs on a cement-retained, implant-supported restoration, the abutment and restoration are completely separated from the implant's internal connection. Traditionally, an access hole is drilled through the crown to retrieve the broken screw, and the restoration can be placed again as a screw-retained restoration. This clinical report documents a patient whose broken abutment screw was retrieved from the restoration by burning off the cement and separating from the abutment without drilling an access hole. PMID:25316610

  12. Regulations and guidelines governing stem cell based products: Clinical considerations

    Directory of Open Access Journals (Sweden)

    Bobby George

    2011-01-01

    Full Text Available The use of stem cells as medicines is a promising and upcoming area of research as they may be able to help the body to regenerate damaged or lost tissue in a host of diseases like Parkinson′s, multiple sclerosis, heart disease, liver disease, spinal cord damage, cancer and many more. Translating basic stem cell research into routine therapies is a complex multi-step process which entails the challenge related to managing the expected therapeutic benefits with the potential risks while complying with the existing regulations and guidelines. While in the United States (US and European Union (EU regulations are in place, in India, we do not have a well-defined regulatory framework for "stem cell based products (SCBP". There are several areas that need to be addressed as it is quite different from that of pharmaceuticals. These range from establishing batch consistency, product stability to product safety and efficacy through pre-clinical, clinical studies and marketing authorization. This review summarizes the existing regulations/guidelines in US, EU, India, and the associated challenges in developing SCBP with emphasis on clinical aspects.

  13. Potential and clinical utility of stem cells in cardiovascular disease

    Directory of Open Access Journals (Sweden)

    Korff Krause

    2010-03-01

    Full Text Available Korff Krause, Carsten Schneider, Kai Jaquet, Karl-Heinz KuckHanseatic Heart Center Hamburg, Department of Cardiology, Asklepios Hospital St. Georg, Hamburg, GermanyAbstract: The recent identification of bone marrow-derived adult stem cells and other types of stem cells that could improve heart function after transplantation have raised high expectations. The basic mechanisms have been studied mostly in murine models. However, these experiments revealed controversial results on transdifferentiation vs transfusion of adult stem cells vs paracrine effects of these cells, which is still being debated. Moreover, the reproducibility of these results in precisely translated large animal models is still less well investigated. Despite these weaknesses results of several clinical trials including several hundreds of patients with ischemic heart disease have been published. However, there are no solid data showing that any of these approaches can regenerate human myocardium. Even the effectiveness of cell therapy in these approaches is doubtful. In future we need in this important field of regenerative medicine: i more experimental data in large animals that are closer to the anatomy and physiology of humans, including data on dose effects, comparison of different cell types and different delivery routes; ii a better understanding of the molecular mechanisms involved in the fate of transplanted cells; iii more intensive research on genuine regenerative medicine, applying genetic regulation and cell engineering.Keywords: stem cells, cardiovascular disease

  14. Clinical Trials With Mesenchymal Stem Cells: An Update.

    Science.gov (United States)

    Squillaro, Tiziana; Peluso, Gianfranco; Galderisi, Umberto

    2016-01-01

    In the last year, the promising features of mesenchymal stem cells (MSCs), including their regenerative properties and ability to differentiate into diverse cell lineages, have generated great interest among researchers whose work has offered intriguing perspectives on cell-based therapies for various diseases. Currently the most commonly used adult stem cells in regenerative medicine, MSCs, can be isolated from several tissues, exhibit a strong capacity for replication in vitro, and can differentiate into osteoblasts, chondrocytes, and adipocytes. However, heterogeneous procedures for isolating and cultivating MSCs among laboratories have prompted the International Society for Cellular Therapy (ISCT) to issue criteria for identifying unique populations of these cells. Consequently, the isolation of MSCs according to ISCT criteria has produced heterogeneous, nonclonal cultures of stromal cells containing stem cells with different multipotent properties, committed progenitors, and differentiated cells. Though the nature and functions of MSCs remain unclear, nonclonal stromal cultures obtained from bone marrow and other tissues currently serve as sources of putative MSCs for therapeutic purposes, and several findings underscore their effectiveness in treating different diseases. To date, 493 MSC-based clinical trials, either complete or ongoing, appear in the database of the US National Institutes of Health. In the present article, we provide a comprehensive review of MSC-based clinical trials conducted worldwide that scrutinizes biological properties of MSCs, elucidates recent clinical findings and clinical trial phases of investigation, highlights therapeutic effects of MSCs, and identifies principal criticisms of the use of these cells. In particular, we analyze clinical trials using MSCs for representative diseases, including hematological disease, graft-versus-host disease, organ transplantation, diabetes, inflammatory diseases, and diseases in the liver, kidney

  15. Percutaneous vertebroplasty and bone cement leakage: clinical experience with a new high-viscosity bone cement and delivery system for vertebral augmentation in benign and malignant compression fractures.

    Science.gov (United States)

    Anselmetti, Giovanni Carlo; Zoarski, Gregg; Manca, Antonio; Masala, Salvatore; Eminefendic, Haris; Russo, Filippo; Regge, Daniele

    2008-01-01

    The aim of this study was to assess the feasibility of and venous leakage reduction in percutaneous vertebroplasty (PV) using a new high-viscosity bone cement (PMMA). PV has been used effectively for pain relief in osteoporotic and malignant vertebral fractures. Cement extrusion is a common problem and can lead to complications. Sixty patients (52 female; mean age, 72.2 +/- 7.2) suffering from osteoporosis (46), malignancy (12), and angiomas (2), divided into two groups (A and B), underwent PV on 190 vertebrae (86 dorsal, 104 lumbar). In Group A, PV with high-viscosity PMMA (Confidence, Disc-O-Tech, Israel) was used. This PMMA was injected by a proprietary delivery system, a hydraulic saline-filled screw injector. In Group B, a standard low-viscosity PMMA was used. Postprocedural CT was carried out to detect PMMA leakages and complications. Fisher's exact test and Wilcoxon rank test were used to assess significant differences (p < 0.05) in leakages and to evaluate the clinical outcome. PV was feasible, achieving good clinical outcome (p < 0.0001) without major complications. In Group A, postprocedural CT showed an asymptomatic leak in the venous structures of 8 of 98 (8.2%) treated vertebrae; a discoidal leak occurred in 6 of 98 (6.1%). In Group B, a venous leak was seen in 38 of 92 (41.3%) and a discoidal leak in 12 of 92 (13.0%). Reduction of venous leak obtained by high-viscosity PMMA was highly significant (p < 0.0001), whereas this result was not significant (p = 0.14) related to the disc. The high-viscosity PMMA system is safe and effective for clinical use, allowing a significant reduction of extravasation rate and, thus, leakage-related complications. PMID:18389186

  16. Research gaps identified during systematic reviews of clinical trials: glass-ionomer cements

    Directory of Open Access Journals (Sweden)

    Mickenautsch Steffen

    2012-06-01

    Full Text Available Abstract Background To report the results of an audit concerning research gaps in clinical trials that were accepted for appraisal in authored and published systematic reviews regarding the application of glass-ionomer cements (GIC in dental practice Methods Information concerning research gaps in trial precision was extracted, following a framework that included classification of the research gap reasons: ‘imprecision of information (results’, ‘biased information’, ‘inconsistency or unknown consistency’ and ‘not the right information’, as well as research gap characterization using PICOS elements: population (P, intervention (I, comparison (C, outcomes (O and setting (S. Internal trial validity assessment was based on the understanding that successful control for systematic error cannot be assured on the basis of inclusion of adequate methods alone, but also requires empirical evidence about whether such attempt was successful. Results A comprehensive and interconnected coverage of GIC-related clinical topics was established. The most common reasons found for gaps in trial precision were lack of sufficient trials and lack of sufficient large sample size. Only a few research gaps were ascribed to ‘Lack of information’ caused by focus on mainly surrogate trial outcomes. According to the chosen assessment criteria, a lack of adequate randomisation, allocation concealment and blinding/masking in trials covering all reviewed GIC topics was noted (selection- and detection/performance bias risk. Trial results appear to be less affected by loss-to-follow-up (attrition bias risk. Conclusion This audit represents an adjunct of the systematic review articles it has covered. Its results do not change the systematic review’s conclusions but highlight existing research gaps concerning the precision and internal validity of reviewed trials in detail. These gaps should be addressed in future GIC-related clinical research.

  17. History of Neural Stem Cell Research and Its Clinical Application.

    Science.gov (United States)

    Takagi, Yasushi

    2016-03-15

    "Once development was ended…in the adult centers, the nerve paths are something fixed and immutable. Everything may die, nothing may be regenerated," wrote Santiago Ramón y Cajal, a Spanish neuroanatomist and Nobel Prize winner and the father of modern neuroscience. This statement was the central dogma in neuroscience for a long time. However, in the 1960s, neural stem cells (NSCs) were discovered. Since then, our knowledge about NSCs has continued to grow. This review focuses on our current knowledge about NSCs and their surrounding microenvironment. In addition, the clinical application of NSCs for the treatment of various central nervous system diseases is also summarized. PMID:26888043

  18. Circulating mesenchymal stem cells and their clinical implications

    Directory of Open Access Journals (Sweden)

    Liangliang Xu

    2014-01-01

    Full Text Available Circulating mesenchymal stem cells (MSCs is a new cell source for tissue regeneration and tissue engineering. The characteristics of circulating MSCs are similar to those of bone marrow-derived MSCs (BM-MSCs, but they exist at a very low level in healthy individuals. It has been demonstrated that MSCs are able to migrate to the sites of injury and that they have some distinct genetic profiles compared to BM-MSCs. The current review summaries the basic knowledge of circulating MSCs and their potential clinical applications, such as mobilizing the BM-MSCs into circulation for therapy. The application of MSCs to cure a broad spectrum of diseases is promising, such as spinal cord injury, cardiovascular repair, bone and cartilage repair. The current review also discusses the issues of using of allogeneic MSCs for clinical therapy.

  19. Characteristics of liver cancer stem cells and clinical correlations.

    Science.gov (United States)

    Cheng, Zhuo; Li, Xiaofeng; Ding, Jin

    2016-09-01

    Liver cancer is an aggressive malignant disease with a poor prognosis. Patients with liver cancer are usually diagnosed at an advanced stage and thus miss the opportunity for surgical resection. Chemotherapy and radiofrequency ablation, which target tumor bulk, have exhibited limited therapeutic efficacy to date. Liver cancer stem cells (CSCs) are a small subset of undifferentiated cells existed in liver cancer, which are considered to be responsible for liver cancer initiation, metastasis, relapse and chemoresistance. Elucidating liver CSC characteristics and disclosing their regulatory mechanism might not only deepen our understanding of the pathogenesis of liver cancer but also facilitate the development of diagnostic, prognostic and therapeutic approaches to improve the clinical management of liver cancer. In this review, we will summarize the recent advances in liver CSC research in terms of the origin, identification, regulation and clinical correlation. PMID:26272183

  20. Ocular Stem Cell Research from Basic Science to Clinical Application: A Report from Zhongshan Ophthalmic Center Ocular Stem Cell Symposium

    Directory of Open Access Journals (Sweden)

    Hong Ouyang

    2016-03-01

    Full Text Available Stem cells hold promise for treating a wide variety of diseases, including degenerative disorders of the eye. The eye is an ideal organ for stem cell therapy because of its relative immunological privilege, surgical accessibility, and its being a self-contained system. The eye also has many potential target diseases amenable to stem cell-based treatment, such as corneal limbal stem cell deficiency, glaucoma, age-related macular degeneration (AMD, and retinitis pigmentosa (RP. Among them, AMD and glaucoma are the two most common diseases, affecting over 200 million people worldwide. Recent results on the clinical trial of retinal pigment epithelial (RPE cells from human embryonic stem cells (hESCs and induced pluripotent stem cells (iPSCs in treating dry AMD and Stargardt’s disease in the US, Japan, England, and China have generated great excitement and hope. This marks the beginning of the ocular stem cell therapy era. The recent Zhongshan Ophthalmic Center Ocular Stem Cell Symposium discussed the potential applications of various stem cell types in stem cell-based therapies, drug discoveries and tissue engineering for treating ocular diseases.

  1. Ocular Stem Cell Research from Basic Science to Clinical Application: A Report from Zhongshan Ophthalmic Center Ocular Stem Cell Symposium

    Science.gov (United States)

    Ouyang, Hong; Goldberg, Jeffrey L.; Chen, Shuyi; Li, Wei; Xu, Guo-Tong; Li, Wei; Zhang, Kang; Nussenblatt, Robert B.; Liu, Yizhi; Xie, Ting; Chan, Chi-Chao; Zack, Donald J.

    2016-01-01

    Stem cells hold promise for treating a wide variety of diseases, including degenerative disorders of the eye. The eye is an ideal organ for stem cell therapy because of its relative immunological privilege, surgical accessibility, and its being a self-contained system. The eye also has many potential target diseases amenable to stem cell-based treatment, such as corneal limbal stem cell deficiency, glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa (RP). Among them, AMD and glaucoma are the two most common diseases, affecting over 200 million people worldwide. Recent results on the clinical trial of retinal pigment epithelial (RPE) cells from human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) in treating dry AMD and Stargardt’s disease in the US, Japan, England, and China have generated great excitement and hope. This marks the beginning of the ocular stem cell therapy era. The recent Zhongshan Ophthalmic Center Ocular Stem Cell Symposium discussed the potential applications of various stem cell types in stem cell-based therapies, drug discoveries and tissue engineering for treating ocular diseases. PMID:27102165

  2. Breast cancer stem cell markers – the rocky road to clinical applications

    OpenAIRE

    Dontu, Gabriela

    2008-01-01

    Lately, understanding the role of cancer stem cells in tumor initiation and progression became a major focus in stem cell biology and in cancer research. Considerable efforts, such as the recent studies by Honeth and colleagues, published in the June issue of Breast Cancer Research, are directed towards developing clinical applications of the cancer stem cell concepts. This work shows that the previously described CD44+CD24- stem cell phenotype is associated with basal-type breast cancers in ...

  3. Islet and stem cell encapsulation for clinical transplantation.

    Science.gov (United States)

    Krishnan, Rahul; Alexander, Michael; Robles, Lourdes; Foster, Clarence E; Lakey, Jonathan R T

    2014-01-01

    Over the last decade, improvements in islet isolation techniques have made islet transplantation an option for a certain subset of patients with long-standing diabetes. Although islet transplants have shown improved graft function, adequate function beyond the second year has not yet been demonstrated, and patients still require immunosuppression to prevent rejection. Since allogeneic islet transplants have experienced some success, the next step is to improve graft function while eliminating the need for systemic immunosuppressive therapy. Biomaterial encapsulation offers a strategy to avoid the need for toxic immunosuppression while increasing the chances of graft function and survival. Encapsulation entails coating cells or tissue in a semipermeable biocompatible material that allows for the passage of nutrients, oxygen, and hormones while blocking immune cells and regulatory substances from recognizing and destroying the cell, thus avoiding the need for systemic immunosuppressive therapy. Despite advances in encapsulation technology, these developments have not yet been meaningfully translated into clinical islet transplantation, for which several factors are to blame, including graft hypoxia, host inflammatory response, fibrosis, improper choice of biomaterial type, lack of standard guidelines, and post-transplantation device failure. Several new approaches, such as the use of porcine islets, stem cells, development of prevascularized implants, islet nanocoating, and multilayer encapsulation, continue to generate intense scientific interest in this rapidly expanding field. This review provides a comprehensive update on islet and stem cell encapsulation as a treatment modality in type 1 diabetes, including a historical outlook as well as current and future research avenues. PMID:25148368

  4. Monitoring cancer stem cells: insights into clinical oncology

    Directory of Open Access Journals (Sweden)

    Lin SC

    2016-02-01

    Full Text Available ShuChen Lin,1,* YingChun Xu,2,* ZhiHua Gan,1 Kun Han,1 HaiYan Hu,3 Yang Yao,3 MingZhu Huang,4 DaLiu Min1 1Department of Oncology, Shanghai Sixth People’s Hospital East Campus, Shanghai Jiao Tong University, 2Department of Oncology, Renji Hospital, Shanghai Jiao Tong University, 3Department of Oncology, The Sixth People’s Hospital, Shanghai Jiao Tong University, 4Department of Medical Oncology, Cancer Hospital of Fudan University, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Cancer stem cells (CSCs are a small, characteristically distinctive subset of tumor cells responsible for tumor initiation and progression. Several treatment modalities, such as surgery, glycolytic inhibition, driving CSC proliferation, immunotherapy, and hypofractionated radiotherapy, may have the potential to eradicate CSCs. We propose that monitoring CSCs is important in clinical oncology as CSC populations may reflect true treatment response and assist with managing treatment strategies, such as defining optimal chemotherapy cycles, permitting pretreatment cancer surveillance, conducting a comprehensive treatment plan, modifying radiation treatment, and deploying rechallenge chemotherapy. Then, we describe methods for monitoring CSCs. Keywords: cancer stem cells, glycolytic inhibition, watchful waiting, rechallenge, immunotherapy

  5. Clinical Applications of Mesenchymal Stem Cells in Chronic Diseases

    Directory of Open Access Journals (Sweden)

    Andrea Farini

    2014-01-01

    Full Text Available Extraordinary progress in understanding several key features of stem cells has been made in the last ten years, including definition of the niche, and identification of signals regulating mobilization and homing as well as partial understanding of the mechanisms controlling self-renewal, commitment, and differentiation. This progress produced invaluable tools for the development of rational cell therapy protocols that have yielded positive results in preclinical models of genetic and acquired diseases and, in several cases, have entered clinical experimentation with positive outcome. Adult mesenchymal stem cells (MSCs are nonhematopoietic cells with multilineage potential to differentiate into various tissues of mesodermal origin. They can be isolated from bone marrow and other tissues and have the capacity to extensively proliferate in vitro. Moreover, MSCs have also been shown to produce anti-inflammatory molecules which can modulate humoral and cellular immune responses. Considering their regenerative potential and immunoregulatory effect, MSC therapy is a promising tool in the treatment of degenerative, inflammatory, and autoimmune diseases. It is obvious that much work remains to be done to increase our knowledge of the mechanisms regulating development, homeostasis, and tissue repair and thus to provide new tools to implement the efficacy of cell therapy trials.

  6. Angled Screw Channel: An Alternative to Cemented Single-Implant Restorations--Three Clinical Examples.

    Science.gov (United States)

    Gjelvold, Björn; Sohrabi, Majid Melvin; Chrcanovic, Bruno Ramos

    2016-01-01

    This article presents three cases of single labially tilted implants restored with screw-retained single crowns. Individualized abutments with an angled screw channel were used to avoid an unesthetic vestibular access channel. This individualized abutment allows the dentist and dental technician to use the screw-retained restorations where a cemented reconstruction would otherwise have been needed. PMID:26757334

  7. Induced pluripotent stem cells: from Nobel Prizes to clinical applications.

    Science.gov (United States)

    Rashid, S Tamir; Alexander, Graeme J M

    2013-03-01

    Advances in basic hepatology have been constrained for many years by the inability to culture primary hepatocytes in vitro, until just over five years ago when the scientific playing field was changed beyond recognition with the demonstration that human skin fibroblasts could be reprogrammed to resemble embryonic cells. The reprogrammed cells, known as induced pluripotent stem cells (iPSCs), were then shown to have the capacity to re-differentiate into almost any human cell type, including hepatocytes. The unlimited number and isogenic nature of the cells that can be generated from tiny fragments of tissue have massive implications for the study of human liver diseases in vitro. Of more immediate clinical importance were recent data demonstrating precision gene therapy on patient specific iPSCs, which opens up the real and exciting possibility of autologous hepatocyte transplantation as a substitute for allogeneic whole liver transplantation, which has been an effective approach to end-stage liver disease, but one that has now been outstripped by demand. In this review, we describe the historical development, current technology and potential clinical applications of induced pluripotency, concluding with a perspective on possible future directions in this dynamic field. PMID:23131523

  8. Bonding All-Ceramic Restorations with Two Resins Cement Techniques: A Clinical Report of Three-Year Follow-Up

    OpenAIRE

    Anchieta, Rodolfo Bruniera; Rocha, Eduardo Passos; de ALMEIDA, Erika Oliveira; Junior, Amilcar Chagas Freitas; Martini, Ana Paula

    2011-01-01

    Ceramics have been widely used for esthetic and functional improvements. The resin cement is the material of choice for bonding ceramics to dental substrate and it can also dictate the final esthetic appearance and strength of the restoration. The correct use of the wide spectrum of resin luting agents available depends on the dental tooth substrate. This article presents three-year clinical results of a 41 years old female patient B.H.C complaining about her unattractive smile. Two all-ceram...

  9. Establishing a stem cell culture laboratory for clinical trials

    Directory of Open Access Journals (Sweden)

    Elíseo Joji Sekiya

    2012-01-01

    Full Text Available Adult stem/progenitor cells are found in different human tissues. An in vitro cell culture is needed for their isolation or for their expansion when they are not available in a sufficient quantity to regenerate damaged organs and tissues. The level of complexity of these new technologies requires adequate facilities, qualified personnel with experience in cell culture techniques, assessment of quality and clear protocols for cell production. The rules for the implementation of cell therapy centers involve national and international standards of good manufacturing practices. However, such standards are not uniform, reflecting the diversity of technical and scientific development. Here standards from the United States, the European Union and Brazil are analyzed. Moreover, practical solutions encountered for the implementation of a cell therapy center appropriate for the preparation and supply of cultured cells for clinical studies are described. Development stages involved the planning and preparation of the project, the construction of the facility, standardization of laboratory procedures and development of systems to prevent cross contamination. Combining the theoretical knowledge of research centers involved in the study of cells with the practical experience of blood therapy services that manage structures for cell transplantation is presented as the best potential for synergy to meet the demands to implement cell therapy centers.

  10. Cement Conundrum

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China aims to streamline the crowded cement industry Policymakers are looking to build a concrete wall around the cement-making industry as they seek to solidify the fluid cement market and cut excessive production.

  11. Stem Cell Therapy for Cardiovascular Disorders - Our Clinical Experience

    Directory of Open Access Journals (Sweden)

    Jayakrishnan AG

    2011-01-01

    Full Text Available Background: Autologous Bone Marrow stem Cell transplantation is a viable therapeutic option for patients with end stage heart failure due to cardiomyopathy of varied etiology as there are only limited treatment options other than cardiac transplantation. The rationale behind the application of stem cells in these patients include • Stem cells directly replace the affected cells by differentiation into the damaged cell type • Stem cells also exert Paracrine effects by secre tion of growth factors (VGEF,FGF-1to stimu late local cell growth•In addition to the above, stem cells release signaling factors which recruit stem cells from elsewhere by modulating the immune system.Materials and Methods: In this presentation we describe our study on a series of 13 patients who received isolated and expanded CD 34 cells from the bone marrow. Seven had ischemic dysfunction, three had dilated cardiomyopathy and three had primary pulmonary hypertension. Five patients received the stem cells via intracoronary injection, three directly into the myocardium and three intrapulmonary. Results: All patients showed functional improvement of the myocardium recorded by non-invasive investigations and improvement in the quality of life. Follow up period ranged from 6 months to 2 years. Conclusion: Our experience with bone marrow derived stem cells in patients with cardiomyopathy has been encouraging. More studies are planned in the future.

  12. RADIATION THERAPY ONCOLOGY GROUP TRANSLATIONAL RESEARCH PROGRAM STEM CELL SYMPOSIUM : INCORPORATING STEM CELL HYPOTHESES INTO CLINICAL TRIALS

    NARCIS (Netherlands)

    Woodward, Wendy A.; Bristow, Robert G.; Clarke, Michael F.; Coppes, Robert P.; Cristofanilli, Massimo; Duda, Dan G.; Fike, John R.; Hambardzumyan, Dolores; Hill, Richard P.; Jordan, Craig T.; Milas, Luka; Pajonk, Frank; Curran, Walter J.; Dicker, Adam P.; Chen, Yuhchyau

    2009-01-01

    At a meeting of the Translation Research Program of the Radiation Therapy Oncology Group held in early 2008, attendees focused on updating the current state of knowledge in cancer stem cell research and discussing ways in which this knowledge can be translated into clinical use across all disease si

  13. Managing the potential and pitfalls during clinical translation of emerging stem cell therapies.

    Science.gov (United States)

    Main, Heather; Munsie, Megan; O'Connor, Michael D

    2014-01-01

    We are moving into a new era of stem cell research where many possibilities for treatment of degenerative, chronic and/or fatal diseases and injuries are becoming primed for clinical trial. These reports have led millions of people worldwide to hope that regenerative medicine is about to revolutionise biomedicine: either through transplantation of cells grown in the laboratory, or by finding ways to stimulate a patient's intrinsic stem cells to repair diseased and damaged organs. While major contributions of stem cells to drug discovery, safety and efficacy testing, as well as modelling 'diseases in a dish' are also expected, it is the in vivo use of stem cells that has captured the general public's attention. However, public misconceptions of stem cell potential and applications can leave patients vulnerable to the influences of profit driven entities selling unproven treatments without solid scientific basis or appropriate clinical testing or follow up. This review provides a brief history of stem cell clinical translation together with an overview of the properties, potential, and current clinical application of various stem cell types. In doing so it presents a clearer picture of the inherent risks and opportunities associated with stem cell research translation, and thus offers a framework to help realise invested expectations more quickly, safely and effectively. PMID:24949190

  14. Fabrication of a maxillary implant-supported overdenture retained by two cemented bars: a clinical report.

    Science.gov (United States)

    Uludag, Bulent; Sahin, Volkan; Celik, Gozde

    2007-05-01

    Parallel placement of 2 separate bars may be indicated in patients where bone is available in the posterior part of the maxilla. Bars and stud attachments are the primary attachment systems compatible with the majority of the implant systems currently available; however, treatment planning in certain situations may be challenging due to the component available with the implant system used. This report describes the fabrication of a cemented bar design for use in situations when the components of the implant system are inadequate for fabrication of a screw-retained bar. PMID:17547940

  15. Culture bag systems for clinical applications of adult human neural crest-derived stem cells

    OpenAIRE

    Greiner, Johannes F. W.; Grunwald, Lena-Marie; Müller, Janine; Sudhoff, Holger; Widera, Darius; Kaltschmidt, Christian; Kaltschmidt, Barbara

    2014-01-01

    Introduction Facing the challenging treatment of neurodegenerative diseases as well as complex craniofacial injuries such as those common after cancer therapy, the field of regenerative medicine increasingly relies on stem cell transplantation strategies. Here, neural crest-derived stem cells (NCSCs) offer many promising applications, although scale up of clinical-grade processes prior to potential transplantations is currently limiting. In this study, we aimed to establish a clinical-grad...

  16. Stem cells and the pancreas: from discovery to clinical approach

    Directory of Open Access Journals (Sweden)

    Angelica Dessì

    2016-02-01

    Full Text Available The existence of stem cells within the adult pancreas is supported by the ability of this organ to regenerate its endocrine component in various conditions such as pregnancy and following partial pancreatectomy. Several studies have shown that progenitor or adult stem cells may reside within the pancreas and particularly in the pancreatic ducts, including acinar cells and islets of Langerhans. The discovery of human pluripotent stem cells in the pancreas, and the possibility of development of strategies for generating these, represented a turning point for the therapeutic interventions of type 1 diabetes.Proceedings of the 2nd International Course on Perinatal Pathology (part of the 11th International Workshop on Neonatology · October 26th-31st, 2015 · Cagliari (Italy · October 31st, 2015 · Stem cells: present and future Guest Editors: Gavino Faa, Vassilios Fanos, Antonio Giordano

  17. Process Engineering of Stem Cells for Clinical Application

    OpenAIRE

    Serra, Maria Margarida de Carvalho Negrão

    2011-01-01

    Over the last decade, human embryonic stem cells (hESCs) have garnered a lot of attention owing to their inherent self-renewal ability and pluripotency. These characteristics have opened opportunities for potential stem cell-based regenerative medicines, for development of drug discovery platforms and as unique in vitro models for the study of early human development.(...) Fundação para a Ciência e a Tecnologia

  18. Clinical Trial Design for Testing the Stem Cell Model for the Prevention and Treatment of Cancer

    International Nuclear Information System (INIS)

    The cancer stem cell model introduces new strategies for the prevention and treatment of cancers. In cancers that appear to follow the stem cell model, pathways such as Wnt, Notch and Hedgehog may be targeted with natural compounds such as curcumin or drugs to reduce the risk of initiation of new tumors. Disease progression of established tumors could also potentially be inhibited by targeting the tumorigenic stem cells alone, rather than aiming to reduce overall tumor size. These new approaches mandate a change in the design of clinical trials and biomarkers chosen for efficacy assessment for preventative, neoadjuvant, adjuvant, and palliative treatments. Cancer treatments could be evaluated by assessing stem cell markers before and after treatment. Targeted stem cell specific treatment of cancers may not result in “complete” or “partial” responses radiologically, as stem cell targeting may not reduce the tumor bulk, but eliminate further tumorigenic potential. These changes are discussed using breast, pancreatic, and lung cancer as examples

  19. Clinical Trial Design for Testing the Stem Cell Model for the Prevention and Treatment of Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Rishindra M., E-mail: reddyrm@med.umich.edu [Medical Center, University of Michigan, 1500 E. Medical Center Drive, 2120 Taubman Center, Ann Arbor, MI 48109 (United States); Kakarala, Madhuri; Wicha, Max S. [Comprehensive Cancer Center, University of Michigan, 1500 E. Medical Center Drive, Ann Arbor, MI 48109 (United States)

    2011-06-20

    The cancer stem cell model introduces new strategies for the prevention and treatment of cancers. In cancers that appear to follow the stem cell model, pathways such as Wnt, Notch and Hedgehog may be targeted with natural compounds such as curcumin or drugs to reduce the risk of initiation of new tumors. Disease progression of established tumors could also potentially be inhibited by targeting the tumorigenic stem cells alone, rather than aiming to reduce overall tumor size. These new approaches mandate a change in the design of clinical trials and biomarkers chosen for efficacy assessment for preventative, neoadjuvant, adjuvant, and palliative treatments. Cancer treatments could be evaluated by assessing stem cell markers before and after treatment. Targeted stem cell specific treatment of cancers may not result in “complete” or “partial” responses radiologically, as stem cell targeting may not reduce the tumor bulk, but eliminate further tumorigenic potential. These changes are discussed using breast, pancreatic, and lung cancer as examples.

  20. [Surgical treatment of a displaced femoral head fracture with a cement-free dual-headed prosthesis using a minimally invasive approach. Clinical and radiographic outcome].

    Science.gov (United States)

    Wick, M; Muhr, G; Rincon, R; Lester, D

    2005-03-01

    One hundred patients treated with a cementless bipolar prosthesis for a displaced subcapital hip fracture were prospectively evaluated for clinical and radiographic outcome. All patients were operated via a minimally invasive approach; in every case we implanted a Zweymuller stem. There were 77 women and 33 men with a mean age of 80 years (29-98 years). The mean duration of the operation was 29 min (20-95 min). Full weight bearing on crutches was allowed 1 day after the operation. The mean follow-up was 2.5 years (6 months to 7 years). Two years after the operation there were 40% of the remaining 65 patients who scored between 90 and 100 on the Harris hip score, 23% between 80 and 89, 20% between 70 and 79, and 17% below 70. No patient complained about thigh pain and up to now there has been no need for femoral revision due to loosening. There was no infection or nerve lesion. In three patients there was a luxation of the prosthesis which could be reduced by closed means. Radiographs from 81 patients showed stress shielding in 97.5% mainly in Gruen zones 1 and 7. Radiolucent lines in two or more Gruen zones were found in two patients. These findings suggest that the noncemented, pressfit, grit-blasted bipolar prosthesis demonstrated similar stability and radiographic results to cemented bipolar prostheses. Stress shielding was common but did not influence longevity of the implant. We did not find any signs of protrusion. Especially in older patients with a history of cardiac disease, the noncemented bipolar prosthesis is a rational alternative to avoid intra- and postoperative complications despite the higher costs for the implant. The minimally invasive approach helps to reduce operation time and intraoperative blood loss. PMID:15778832

  1. Regulations and guidelines governing stem cell based products: Clinical considerations

    OpenAIRE

    Bobby George

    2011-01-01

    The use of stem cells as medicines is a promising and upcoming area of research as they may be able to help the body to regenerate damaged or lost tissue in a host of diseases like Parkinson′s, multiple sclerosis, heart disease, liver disease, spinal cord damage, cancer and many more. Translating basic stem cell research into routine therapies is a complex multi-step process which entails the challenge related to managing the expected therapeutic benefits with the potential risks while comply...

  2. Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations

    Directory of Open Access Journals (Sweden)

    Brad B Swelstad

    2009-12-01

    Full Text Available Brad B Swelstad, Candace L KerrInstitute for Cell Engineering, Department of Obstetrics and Gynecology, Johns Hopkins University, Baltimore, MA, USAAbstract: Pluripotent stem cells have been derived from various embryonic, fetal and adult sources. Embryonic stem cells (ESCs and parthenogenic ESCs (pESCs are derived from the embryo proper while embryonic germ cells (EGCs, embryonal carcinoma cells (ECCs, and germ-line stem cells (GSC are produced from germ cells. ECCs were the first pluripotent stem cell lines established from adult testicular tumors while EGCs are generated in vitro from primordial germ cells (PGCs isolated in late embryonic development. More recently, studies have also demonstrated the ability to produce GSCs from adult germ cells, known as spermatogonial stem cells. Unlike ECCs, the source of GSCs are normal, non-cancerous adult tissue. The study of these unique cell lines has provided information that has led to the ability to reprogram somatic cells into an ESC-like state. These cells, called induced pluripotent stem cells (iPSCs, have been derived from a number of human fetal and adult origins. With the promises pluripotent stem cells bring to cell-based therapies there remain several considerations that need to be carefully studied prior to their clinical use. Many of these issues involve understanding key factors regulating their generation, including those which define pluripotency. In this regard, the following article discusses critical aspects of pluripotent stem cell derivation and current issues about their therapeutic potential.Keywords: pluripotency, stem cells, derivation, human

  3. Clinical Implications of Intestinal Stem Cell Markers in Colorectal Cancer

    DEFF Research Database (Denmark)

    Espersen, Maiken Lise Marcker; Olsen, Jesper; Linnemann, Dorte;

    2015-01-01

    Colorectal cancer (CRC) still has one of the highest incidence and mortality rate among cancers. Therefore, improved differential diagnostics and personalized treatment are still needed. Several intestinal stem cell markers have been found to be associated with CRC and might have a prognostic and...

  4. Radiation Therapy Oncology Group Translational Research Program Stem Cell Symposium: Incorporating Stem Cell Hypotheses into Clinical Trials

    International Nuclear Information System (INIS)

    At a meeting of the Translation Research Program of the Radiation Therapy Oncology Group held in early 2008, attendees focused on updating the current state of knowledge in cancer stem cell research and discussing ways in which this knowledge can be translated into clinical use across all disease sites. This report summarizes the major topics discussed and the future directions that research should take. Major conclusions of the symposium were that the flow cytometry of multiple markers in fresh tissue would remain the standard technique of evaluating cancer-initiating cells and that surrogates need to be developed for both experimental and clinical use.

  5. Setting Global Standards for Stem Cell Research and Clinical Translation: The 2016 ISSCR Guidelines.

    Science.gov (United States)

    Daley, George Q; Hyun, Insoo; Apperley, Jane F; Barker, Roger A; Benvenisty, Nissim; Bredenoord, Annelien L; Breuer, Christopher K; Caulfield, Timothy; Cedars, Marcelle I; Frey-Vasconcells, Joyce; Heslop, Helen E; Jin, Ying; Lee, Richard T; McCabe, Christopher; Munsie, Megan; Murry, Charles E; Piantadosi, Steven; Rao, Mahendra; Rooke, Heather M; Sipp, Douglas; Studer, Lorenz; Sugarman, Jeremy; Takahashi, Masayo; Zimmerman, Mark; Kimmelman, Jonathan

    2016-06-14

    The International Society for Stem Cell Research (ISSCR) presents its 2016 Guidelines for Stem Cell Research and Clinical Translation (ISSCR, 2016). The 2016 guidelines reflect the revision and extension of two past sets of guidelines (ISSCR, 2006; ISSCR, 2008) to address new and emerging areas of stem cell discovery and application and evolving ethical, social, and policy challenges. These guidelines provide an integrated set of principles and best practices to drive progress in basic, translational, and clinical research. The guidelines demand rigor, oversight, and transparency in all aspects of practice, providing confidence to practitioners and public alike that stem cell science can proceed efficiently and remain responsive to public and patient interests. Here, we highlight key elements and recommendations in the guidelines and summarize the recommendations and deliberations behind them. PMID:27185282

  6. Setting Global Standards for Stem Cell Research and Clinical Translation: The 2016 ISSCR Guidelines

    Directory of Open Access Journals (Sweden)

    George Q. Daley

    2016-06-01

    Full Text Available The International Society for Stem Cell Research (ISSCR presents its 2016 Guidelines for Stem Cell Research and Clinical Translation (ISSCR, 2016. The 2016 guidelines reflect the revision and extension of two past sets of guidelines (ISSCR, 2006; ISSCR, 2008 to address new and emerging areas of stem cell discovery and application and evolving ethical, social, and policy challenges. These guidelines provide an integrated set of principles and best practices to drive progress in basic, translational, and clinical research. The guidelines demand rigor, oversight, and transparency in all aspects of practice, providing confidence to practitioners and public alike that stem cell science can proceed efficiently and remain responsive to public and patient interests. Here, we highlight key elements and recommendations in the guidelines and summarize the recommendations and deliberations behind them.

  7. Adipose Derived Mesenchymal Stem Cells In Wound Healing: A Clinical Review

    Directory of Open Access Journals (Sweden)

    Gunalp Uzun

    2014-08-01

    Full Text Available The aim of this article is to review clinical studies on the use of adipose derived mesenchymal stem cells in the treatment of chronic wounds. A search on PubMed was performed on April 30th, 2014 to identify the relevant clinical studies. We reviewed 13 articles that reported the use adipose derived stem cells in the treatment of different types of wounds. Adipose derived stem cells have the potential to be used in the treatment of chronic wounds. However, standard methods for isolation, storage and application of these cells are needed. New materials to transfer these stem cells to injured tissues should be investigated. [Dis Mol Med 2014; 2(4.000: 57-64

  8. Managing the potential and pitfalls during clinical translation of emerging stem cell therapies

    OpenAIRE

    Main, Heather; Munsie, Megan; O’Connor, Michael D

    2014-01-01

    We are moving into a new era of stem cell research where many possibilities for treatment of degenerative, chronic and/or fatal diseases and injuries are becoming primed for clinical trial. These reports have led millions of people worldwide to hope that regenerative medicine is about to revolutionise biomedicine: either through transplantation of cells grown in the laboratory, or by finding ways to stimulate a patient’s intrinsic stem cells to repair diseased and damaged organs. While major ...

  9. Mesenchymal Stem Cell-Derived Extracellular Vesicles Promote Angiogenesis: Potencial Clinical Application

    OpenAIRE

    Merino-González, Consuelo; Zuñiga, Felipe A.; Escudero, Carlos; Ormazabal, Valeska; Reyes, Camila; Nova-Lamperti, Estefanía; Salomón, Carlos; Aguayo, Claudio

    2016-01-01

    Mesenchymal stem cells (MSCs) are adult multipotent stem cells that are able to differentiate into multiple specialized cell types including osteocytes, adipocytes, and chondrocytes. MSCs exert different functions in the body and have recently been predicted to have a major clinical/therapeutic potential. However, the mechanisms of self-renewal and tissue regeneration are not completely understood. It has been shown that the biological effect depends mainly on its paracrine action. Furthermor...

  10. Hematopoietic stem cell transplantation: clinical use and perspectives

    OpenAIRE

    Francisco Barriga; Pablo Ramírez; Angélica Wietstruck; Nicolás Rojas

    2012-01-01

    Hematopoietic stem cell transplantation is the accepted therapy of choice for a variety of malignant and non-malignant diseases in children and adults. Initially developed as rescue therapy for a patient with cancer after high doses of chemotherapy and radiation as well as the correction of severe deficiencies in the hematopoietic system, it has evolved into an adoptive immune therapy for malignancies and autoimmune disorders. The procedure has helped to obtain key information about the bone ...

  11. Ambivalent journeys of hope: embryonic stem cell therapy in a clinic in India.

    Science.gov (United States)

    Prasad, Amit

    2015-03-01

    Stem cell therapy in non-Western countries such as India has received a lot of attention. Apart from media reports, there are a number of social science analyses of stem cell policy, therapy, and research, their ethical implications, and impact of advertising on patients. Nevertheless, in the media reports as well as in academic studies, experiences of patients, who undertake overseas journeys for stem cell therapy, have largely been either ignored or presented reductively, often as a "false hope." In this article, I analyze the experiences of patients and their "journeys of hope" to NuTech Mediworld, an embryonic stem cell therapy clinic in New Delhi, India. My analysis, which draws on my observations in the clinic and patients' experiences, instead of seeking to adjudicate whether embryonic stem cell therapy in clinics such as NuTech is right or wrong, true or false, focuses on how patients navigate and contest these concerns. I utilize Gilles Deleuze and Felix Guattari's "concepts," lines of flight and deterritorialization, to highlight how embryonic stem cell therapy's "political economy of hope" embodies deterritorialization of several "regimes of truth" and how these deterritorializations impact patients' experiences. PMID:25394653

  12. TOPICAL REVIEW: Stem cell technology using bioceramics: hard tissue regeneration towards clinical application

    Science.gov (United States)

    Ohnishi, Hiroe; Oda, Yasuaki; Ohgushi, Hajime

    2010-02-01

    Mesenchymal stem cells (MSCs) are adult stem cells which show differentiation capabilities toward various cell lineages. We have already used MSCs for treatments of osteoarthritis, bone necrosis and bone tumor. For this purpose, culture expanded MSCs were combined with various ceramics and then implanted. Because of rejection response to allogeneic MSC implantation, we have utilized patients' own MSCs for the treatment. Bone marrow is a good cell source of MSCs, although the MSCs also exist in adipose tissue. When comparing osteogenic differentiation of these MSCs, bone marrow MSCs show more extensive bone forming capability than adipose MSCs. Thus, the bone marrow MSCs are useful for bone tissue regeneration. However, the MSCs show limited proliferation and differentiation capabilities that hindered clinical applications in some cases. Recent advances reveal that transduction of plural transcription factors into human adult cells results in generation of new type of stem cells called induced pluripotent stem cells (iPS cells). A drawback of the iPS cells for clinical applications is tumor formation after their in vivo implantation; therefore it is difficult to use iPS cells for the treatment. To circumvent the problem, we transduced a single factor of either SOX2 or NANOG into the MSCs and found high proliferation as well as osteogenic differentiation capabilities of the MSCs. The stem cells could be combined with bioceramics for clinical applications. Here, we summarize our recent technologies using adult stem cells in viewpoints of bone tissue regeneration.

  13. Mesenchymal Stem Cells Isolated from Adipose and Other Tissues: Basic Biological Properties and Clinical Applications

    Directory of Open Access Journals (Sweden)

    Hakan Orbay

    2012-01-01

    Full Text Available Mesenchymal stem cells (MSCs are adult stem cells that were initially isolated from bone marrow. However, subsequent research has shown that other adult tissues also contain MSCs. MSCs originate from mesenchyme, which is embryonic tissue derived from the mesoderm. These cells actively proliferate, giving rise to new cells in some tissues, but remain quiescent in others. MSCs are capable of differentiating into multiple cell types including adipocytes, chondrocytes, osteocytes, and cardiomyocytes. Isolation and induction of these cells could provide a new therapeutic tool for replacing damaged or lost adult tissues. However, the biological properties and use of stem cells in a clinical setting must be well established before significant clinical benefits are obtained. This paper summarizes data on the biological properties of MSCs and discusses current and potential clinical applications.

  14. In utero stem cell transplantation and gene therapy: Recent progress and the potential for clinical application.

    Science.gov (United States)

    McClain, Lauren E; Flake, Alan W

    2016-02-01

    Advances in prenatal diagnosis have led to the prenatal management and treatment of a variety of congenital diseases. Although surgical treatment has been successfully applied to specific anatomic defects that place the fetus at a risk of death or life-long disability, the indications for fetal surgical intervention have remained relatively limited. By contrast, prenatal stem cell and gene therapy await clinical application, but they have tremendous potential to treat a broad range of genetic disorders. If there are biological advantages unique to fetal development that favor fetal stem cell or gene therapy over postnatal treatment, prenatal therapy may become the preferred approach to the treatment of any disease that can be prenatally diagnosed and cured by stem cell or gene therapy. Here, we review the field including recent progress toward clinical application and imminent clinical trials for cellular and gene therapy. PMID:26483174

  15. Cytotoxicity of glass ionomer cement on human exfoliated deciduous teeth stem cells correlates with released fluoride, strontium and aluminum ion concentrations

    Directory of Open Access Journals (Sweden)

    Kanjevac Tatjana V.

    2015-01-01

    Full Text Available Stem cells from human exfoliated deciduous teeth (SHED can be used as a cell-based therapy in regenerative medicine and in immunomodulation. Pulp from human deciduous teeth can be stored as a source of SHED. Glass ionomer cements (GICs are commonly used in restorative dentistry and in cavity lining. GICs have lower biocompatibility and are cytotoxic for dental pulp cells. In this study, seven commonly used GICs were tested for their cytotoxic effects on SHED, for their potential to arrest mitosis in cells and induce chromosome aberrations, and were compared with the effects of composite. Fuji II, Fuji VIII, Fuji IX, Fuji plus and Vitrebond had significantly higher cytotoxic effects on SHED than composite. Only SHEDs that have been treated with Fuji I, Fuji IX, Fuji plus and composite recovered the potential for proliferation, but no chromosome aberrations were found after treatment with GICs. The cytotoxic effects of GICs on SHEDs were in strong correlation with combined concentrations of released fluoride, aluminum and strontium ions. Fuji I exhibited the lowest activity towards SHEDs; it did not interrupt mitosis and did not induce chromosome aberrations, and was accompanied by the lowest levels of released F, Al and Sr ions. Projekat Ministarstva nauke Republike Srbije, br. ON175069, br. ON175071 i br. ON175103

  16. Ovarian stem cells: From basic to clinical applications

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The field of reproductive biology has undergone significantdevelopments in the last decade. The notion thatthere is a fixed reserve pool of oocytes before birth wasestablished by Zuckerman in 1951. However, in 2004,an article published in nature challenged this centraldogma of mammalian reproductive biology. Tilly's groupreported the existence of ovarian germline stem cells(GSCs) in postnatal ovaries of mice and suggested thatthe bone marrow could be an extragonadal source ofovarian GSCs. These findings were strongly criticized;however, several independent groups have sincesuccessfully isolated and characterized ovarian GSCsin postnatal mice. The ovarian GSCs are located in theovarian surface epithelium and express markers ofundifferentiated GSCs. When transplanted into mouseovaries, mouse ovarian GSCs could differentiate andproduce embryos and offspring. Similarly, in a recentstudy, ovarian GSCs were found to be present in theovaries of women of reproductive age. Conversely,there is increasing evidence that stem cells responsiblefor maintaining a healthy state in normal tissue maybe a source of some cancers, including ovarian cancer.Cancer stem cells (CSCs) have been found in manytissues, including ovaries. Some researchers havesuggested that ovarian cancer may be a result of thetransformation and dysfunction of ovarian GSCs withself-renewal properties. Drug resistant and metastasisgeneratingCSCs are responsible for many importantproblems affecting ovarian cancer patients. Therefore,the identification of CSCs will provide opportunitiesfor the development of new therapeutic strategies fortreatments for infertility and ovarian cancer. In thisarticle, we summarize the current understanding ofovarian GSCs in adult mammals, and we also discusswhether there is a relationship between GSCs and CSCs.

  17. Ovarian stem cells: From basic to clinical applications.

    Science.gov (United States)

    Ozakpinar, Ozlem Bingol; Maurer, Anne-Marie; Ozsavci, Derya

    2015-05-26

    The field of reproductive biology has undergone significant developments in the last decade. The notion that there is a fixed reserve pool of oocytes before birth was established by Zuckerman in 1951. However, in 2004, an article published in nature challenged this central dogma of mammalian reproductive biology. Tilly's group reported the existence of ovarian germline stem cells (GSCs) in postnatal ovaries of mice and suggested that the bone marrow could be an extragonadal source of ovarian GSCs. These findings were strongly criticized; however, several independent groups have since successfully isolated and characterized ovarian GSCs in postnatal mice. The ovarian GSCs are located in the ovarian surface epithelium and express markers of undifferentiated GSCs. When transplanted into mouse ovaries, mouse ovarian GSCs could differentiate and produce embryos and offspring. Similarly, in a recent study, ovarian GSCs were found to be present in the ovaries of women of reproductive age. Conversely, there is increasing evidence that stem cells responsible for maintaining a healthy state in normal tissue may be a source of some cancers, including ovarian cancer. Cancer stem cells (CSCs) have been found in many tissues, including ovaries. Some researchers have suggested that ovarian cancer may be a result of the transformation and dysfunction of ovarian GSCs with self-renewal properties. Drug resistant and metastasis-generating CSCs are responsible for many important problems affecting ovarian cancer patients. Therefore, the identification of CSCs will provide opportunities for the development of new therapeutic strategies for treatments for infertility and ovarian cancer. In this article, we summarize the current understanding of ovarian GSCs in adult mammals, and we also discuss whether there is a relationship between GSCs and CSCs. PMID:26029346

  18. Identification of stem-like cells and clinical significance of candidate stem cell markers in gastric cancer

    Science.gov (United States)

    Wang, Xiaofeng; Huang, Mingzhu; Gan, Lu; Wu, Zhenhua; Zhang, Jiejun; Wang, Hongqiang; Cheng, Yufan; Li, Jin; Guo, Weijian

    2016-01-01

    The existence of gastric cancer stem cells (CSCs) has not been definitively proven and specific cell surface markers for identifying gastric CSCs have largely not been identified. Our research aimed to isolate potential gastric CSCs and clarify their clinical significance, while defining markers for GCSC identification and verification. Here, we report that spheroid cells possess stem cell-like properties, and overexpress certain stem cell markers. CD133 or CD44-positive cells also exhibit properties of CSCs. The expression of Oct4, Sox2, Gli1, CD44, CD133, p-AKT, and p-ERK was significantly higher in metastatic lesions compared to that in primary lesions. Elevated expression of some of these proteins was correlated with a more aggressive phenotype and poorer prognosis, including Oct4, Sox2, Gli1, CD44, and p-ERK. Multivariate Cox proportional hazards model analysis showed that only CD44 is an independent factor. Knockdown of CD44 down-regulated the stem cell-like properties, which was accompanied by the down-regulation of p-ERK and Oct4. Oct4 overexpression could reverse the decreased CSCs properties induced by CD44 knockdown. Taken together, our research revealed that spheroid cell culture, and CD133 or CD44-labeled FACS methods can be used to isolate gastric CSCs. Some CSC markers have clinical significance in predicting the prognosis. CD44 is an independent prognostic factor and maintains the properties of CSCs in CD44-p-ERK-Oct4 positive feedback loop. PMID:26769843

  19. Cement Formation

    DEFF Research Database (Denmark)

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten;

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including an...... overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid...

  20. Preliminary study using pulsating water jet for bone cement demolition

    OpenAIRE

    S. Hloch; Kloc, J.; Foldyna, J.; Pude, F.; Smolko, I.; M. Zeleňák; Sitek, L. (Libor); Hvizdoš, P.; Monka, P.; Monková, K.; Kozak, D.; A. Stoić; A. Sedmak; Milosevic, M; Lehocká, D.

    2015-01-01

    The paper deals with the study of using the selective property of ultrasonic pulsating water jet for the disintegration of bone cement which creates the interface between femoral stem and trabecular bone tissue. For investigation, commercial bone cements were used. Bone cements were tested by nanoindentation in order to review their mechanical properties. A representative sample Palacos R+G was selected for disintegration of bone cement. Bone cements samples fixed between two plexiglass...

  1. Stem cells in the heart: What’s the buzz all about? Part 2: Arrhythmic risks and clinical studies

    OpenAIRE

    Smith, Rachel Ruckdeschel; Barile, Lucio; Messina, Elisa; Marbán, Eduardo

    2008-01-01

    New approaches for cardiac repair have been enabled by the discovery that the heart contains its own reservoir of stem cells. In Part 1 of this review, we discussed various cardiac stem cell populations, reviewed our own work on cardiosphere-derived cells from human hearts, and outlined large animal preclinical models testing the regenerative potential of cardiac stem cells. Here we continue with a discussion on other adult stem cell sources with clinical potential. We summarize the critical ...

  2. Stem cell therapy for joint problems using the horse as a clinically relevant animal model

    DEFF Research Database (Denmark)

    Koch, Thomas Gadegaard; Betts, Dean H.

    2007-01-01

    of the developmental biology of synovial joints and their pathologies. Before human clinical trials are undertaken, stem cell-based therapies for non-life-threatening disorders should be evaluated for their safety and efficacy using animal models of spontaneous disease and not solely by the existing laboratory models...... of experimentally induced lesions. The horse lends itself as a good animal model of spontaneous joint disorders that are clinically relevant to similar human disorders. Equine stem cell and tissue engineering studies may be financially feasible to principal investigators and small biotechnology companies......Research into articular cartilage is a surprisingly recent endeavour and much remains to be learned about the normal development of the synovial joint and its components that interplay in osteoarthritis and focal cartilage defects. Stem cell research is likely to contribute to the understanding...

  3. An update of human mesenchymal stem cell biology and their clinical uses

    DEFF Research Database (Denmark)

    Zaher, Walid; Harkness, Linda; Kermani, Abbas Jafari;

    2014-01-01

    in vivo. Consequently, stromal (mesenchymal) stem cells (MSCs) are being introduced into many clinical trials due to their ease of isolation and efficacy in treating a number of disease conditions in animal preclinical disease models. The aim of this review is to revise MSC biology, their potential...

  4. Clinical Application of Stem Cells in the Cardiovascular System

    Science.gov (United States)

    Stamm, Christof; Klose, Kristin; Choi, Yeong-Hoon

    Regenerative medicine encompasses "tissue engineering" - the in vitro fabrication of tissues and/or organs using scaffold material and viable cells - and "cell therapy" - the transplantation or manipulation of cells in diseased tissue in vivo. In the cardiovascular system, tissue engineering strategies are being pursued for the development of viable replacement blood vessels, heart valves, patch material, cardiac pacemakers and contractile myocardium. Anecdotal clinical applications of such vessels, valves and patches have been described, but information on systematic studies of the performance of such implants is not available, yet. Cell therapy for cardiovascular regeneration, however, has been performed in large series of patients, and numerous clinical studies have produced sometimes conflicting results. The purpose of this chapter is to summarize the clinical experience with cell therapy for diseases of the cardiovascular system, and to analyse possible factors that may influence its outcome.

  5. Clinical relevance of KIRs in hematopoietic stem cell transplantation

    Directory of Open Access Journals (Sweden)

    Vojvodić Svetlana

    2010-01-01

    Full Text Available Introduction Natural Killer cells (NK cells represent the subset of peripheral lymphocytes that play critical role in the innate immune response to virus-infected and tumor transformed cells. Lysis of NK sensitived target cells could be mediated independently of antigen stimulation, and unlike cytotoxic T-lymphocytes, they do not require peptide presentation by the major histocompatibility complex (MHC molecules. NK cell cytotoxic activity is controlled by considerable number of cell surface Killer cell Immunoglobulin like Receptors (KIRs, which can exist in both inhibitory and activating isoforms. The inhibitory KIRs are mostly specific for HLA class I ligands and I HLA class like molecules, while the specificity of activating receptors is regarded to lectine-like superfamily. The role of NK cells in allogeneic haematopoietic stem cell transplantation (HSCT: NK cells are the first lymphocyte subset that reconstitute the peripheral blood following allogeneic HSCT. By selecting donors mismatched for relevant HLA ligands in the context of recipients KIR genotype, multiple roles for alloreactive donor NK cells have been demonstrated, in diminishing Graft vs. Host Disease (GvHD through selective killing of recipient dendritic cells, prevention of graft rejection by killing recipient T cells and participation in Graft vs. Leukaemia (GvL effect through destruction of residual host tumor cells. Conclusion Investigation of KIRs heterogenity play an important role in the field of HSCT, because it is useful for the early diagnosis of post transplant complications and can serve as a predictive risk factor for GvHD development.

  6. Toward clinical application of stem cells for cardiac regeneration.

    Science.gov (United States)

    Stubbs, Samantha L; Crook, Jeremy M; Morrison, Wayne A; Newcomb, Andrew E

    2011-03-01

    Heart failure affects more than 10% of the Australian population over age 65, and the ageing population will ensure continued growth of this significant problem. There are various treatment options available, but the growing field of regenerative therapy offers promise to restore or replace tissue lost in those with either congenital or acquired cardiac defects. Stem cells have many potential properties, but they need multiple discussed qualities to succeed in this field such as ease of harvest and multiplication, and most importantly minimal ethical concerns. There are multiple cell types available and one of the challenges will be to find the most appropriate cell type for cardiac regeneration. Cardiac tissue engineering is being explored using both in vitro and in vivo techniques. In vitro methods are primarily limited in terms of the vascularisation and size of the construct. In vivo engineered constructs overcome these limitations in early models, but they are still not ready for human trials. This review aims to provide the reader with an outline of the cell-based and tissue engineering therapies currently being used and developed for cardiac regeneration, as well as some insight into the potential problems that may hamper its progress in the future. PMID:20650685

  7. Concepts for the clinical use of stem cells in equine medicine

    DEFF Research Database (Denmark)

    Koch, Thomas Gadegaard; Berg, Lise Charlotte; Betts, Dean H.

    2008-01-01

    Stem cells from various tissues hold great promise for their therapeutic use in horses, but so far efficacy or proof-of-principle has not been established. The basic characteristics and properties of various equine stem cells remain largely unknown, despite their increasingly widespread experimen...... to move this new equine research field forward. Stem cell research in the horse has exciting equine specific and comparative perspectives that will most likely benefit the health of horses and, potentially, humans.......Stem cells from various tissues hold great promise for their therapeutic use in horses, but so far efficacy or proof-of-principle has not been established. The basic characteristics and properties of various equine stem cells remain largely unknown, despite their increasingly widespread...... experimental and empirical commercial use. A better understanding of equine stem cell biology and concepts is needed in order to develop and evaluate rational clinical applications in the horse. Controlled, well-designed studies of the basic biologic characteristics and properties of these cells are needed...

  8. Advances in the Use of Stem Cells in Veterinary Medicine: From Basic Research to Clinical Practice.

    Science.gov (United States)

    Markoski, Melissa Medeiros

    2016-01-01

    Today, several veterinary diseases may be treated with the administration of stem cells. This is possible because these cells present a high therapeutic potential and may be injected as autologous or allogenic, freshly isolated, or previously cultured. The literature supports that the process is safe and brings considerable benefits to animal health. Knowledge about how adult stem cells modulate the molecular signals to activate cell homing has also been increasingly determined, evidencing the mechanisms which enable cells to repair and regenerate injured tissues. Preclinical studies were designed for many animal models and they have contributed to the translation to the human clinic. This review shows the most commonly used stem cell types, with emphasis on mesenchymal stem cells and their mechanistic potential to repair, as well as the experimental protocols, studied diseases, and species with the highest amount of studies and applications. The relationship between stem cell protocols utilized on clinics, molecular mechanisms, and the physiological responses may offer subsidies to new studies and therefore improve the therapeutic outcome for both humans and animals. PMID:27379197

  9. Advances in the Use of Stem Cells in Veterinary Medicine: From Basic Research to Clinical Practice

    Directory of Open Access Journals (Sweden)

    Melissa Medeiros Markoski

    2016-01-01

    Full Text Available Today, several veterinary diseases may be treated with the administration of stem cells. This is possible because these cells present a high therapeutic potential and may be injected as autologous or allogenic, freshly isolated, or previously cultured. The literature supports that the process is safe and brings considerable benefits to animal health. Knowledge about how adult stem cells modulate the molecular signals to activate cell homing has also been increasingly determined, evidencing the mechanisms which enable cells to repair and regenerate injured tissues. Preclinical studies were designed for many animal models and they have contributed to the translation to the human clinic. This review shows the most commonly used stem cell types, with emphasis on mesenchymal stem cells and their mechanistic potential to repair, as well as the experimental protocols, studied diseases, and species with the highest amount of studies and applications. The relationship between stem cell protocols utilized on clinics, molecular mechanisms, and the physiological responses may offer subsidies to new studies and therefore improve the therapeutic outcome for both humans and animals.

  10. Cementing porcelain-fused-to-metal crowns.

    Science.gov (United States)

    Vadachkoria, D

    2009-12-01

    The clinical success of fixed prosthodontic restorations can be complex and involve multifaceted procedures. Preparation design, oral hygiene/micro flora, mechanical forces, and restorative materials are only a few of the factors which contribute to overall success. One key factor to success is choosing the proper cement. Popular use of cements for PFM crowns has shifted from zinc phosphate and glass ionomer cements to resin-reinforced glass ionomer, or RRGI, cements. This change has been rapid and profound. Dental cements have always been less than ideal materials, but this is shift to the relatively new RRGI category justified. Resin-reinforced glass ionomer (RRGI) cements appear to be better than zinc phosphate and glass ionomer cements when placing porcelain-to-metal crowns. RRGI cements, such as RelyX Luting, Fuji Plus and Vitremer Luting Cement, satisfy more of the ideal characteristics of PFM cementation than any other previous cement. Expansion of all three cements has not caused any apparent problems with the cements when used with PFM or metal crowns, but these cements, however, should be avoided when cementing all-ceramic crowns. PMID:20090144

  11. The prognostic value of clinical factors and cancer stem cell-related markers in gliomas

    DEFF Research Database (Denmark)

    Dahlrot, Rikke Hedegaard

    2014-01-01

    -renewal, proliferation, and differentiation during development of different (normal) tissues. The same characteristics were identified in cancer cells, and recently a major part of the glioma research has focused on the cancer stem cell (CSC) hypothesis, suggesting that only CSCs posses the ability of initiating new...... on experiences from clinical trials, with the risk that the results obtained are restricted to highly selected patients only. Moreover, these studies provided only little knowledge of the clinical behaviour of the tumours. For some time, it has been believed that somatic stem cells are responsible for self...... knowledge about the biological but also about the clinical presentation of gliomas and of glioma patients in an entire population was needed. Identification of patients who would benefit from standard treatment as well as identification of patients who need more aggressive treatment at the time of diagnosis...

  12. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    OpenAIRE

    Nediljka Gaurina-Međimurec; Davorin Matanović; Gracijan Krklec

    1994-01-01

    During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures) and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production...

  13. A Clinical Indications Prediction Scale Based on TWIST1 for Human Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Siddaraju V. Boregowda

    2016-02-01

    Full Text Available In addition to their stem/progenitor properties, mesenchymal stem cells (MSCs also exhibit potent effector (angiogenic, antiinflammatory, immuno-modulatory functions that are largely paracrine in nature. It is widely believed that effector functions underlie most of the therapeutic potential of MSCs and are independent of their stem/progenitor properties. Here we demonstrate that stem/progenitor and effector functions are coordinately regulated at the cellular level by the transcription factor Twist1 and specified within populations according to a hierarchical model. We further show that manipulation of Twist1 levels by genetic approaches or by exposure to widely used culture supplements including fibroblast growth factor 2 (Ffg2 and interferon gamma (IFN-gamma alters MSC efficacy in cell-based and in vivo assays in a predictable manner. Thus, by mechanistically linking stem/progenitor and effector functions our studies provide a unifying framework in the form of an MSC hierarchy that models the functional complexity of populations. Using this framework, we developed a CLinical Indications Prediction (CLIP scale that predicts how donor-to-donor heterogeneity and culture conditions impact the therapeutic efficacy of MSC populations for different disease indications.

  14. A Clinical Indications Prediction Scale Based on TWIST1 for Human Mesenchymal Stem Cells.

    Science.gov (United States)

    Boregowda, Siddaraju V; Krishnappa, Veena; Haga, Christopher L; Ortiz, Luis A; Phinney, Donald G

    2016-02-01

    In addition to their stem/progenitor properties, mesenchymal stem cells (MSCs) also exhibit potent effector (angiogenic, antiinflammatory, immuno-modulatory) functions that are largely paracrine in nature. It is widely believed that effector functions underlie most of the therapeutic potential of MSCs and are independent of their stem/progenitor properties. Here we demonstrate that stem/progenitor and effector functions are coordinately regulated at the cellular level by the transcription factor Twist1 and specified within populations according to a hierarchical model. We further show that manipulation of Twist1 levels by genetic approaches or by exposure to widely used culture supplements including fibroblast growth factor 2 (Ffg2) and interferon gamma (IFN-gamma) alters MSC efficacy in cell-based and in vivo assays in a predictable manner. Thus, by mechanistically linking stem/progenitor and effector functions our studies provide a unifying framework in the form of an MSC hierarchy that models the functional complexity of populations. Using this framework, we developed a CLinical Indications Prediction (CLIP) scale that predicts how donor-to-donor heterogeneity and culture conditions impact the therapeutic efficacy of MSC populations for different disease indications. PMID:26981553

  15. Pre-Clinical Cell-Based Therapy for Limbal Stem Cell Deficiency.

    Science.gov (United States)

    Sehic, Amer; Utheim, Øygunn Aass; Ommundsen, Kristoffer; Utheim, Tor Paaske

    2015-01-01

    The cornea is essential for normal vision by maintaining transparency for light transmission. Limbal stem cells, which reside in the corneal periphery, contribute to the homeostasis of the corneal epithelium. Any damage or disease affecting the function of these cells may result in limbal stem cell deficiency (LSCD). The condition may result in both severe pain and blindness. Transplantation of ex vivo cultured cells onto the cornea is most often an effective therapeutic strategy for LSCD. The use of ex vivo cultured limbal epithelial cells (LEC), oral mucosal epithelial cells, and conjunctival epithelial cells to treat LSCD has been explored in humans. The present review focuses on the current state of knowledge of the many other cell-based therapies of LSCD that have so far exclusively been explored in animal models as there is currently no consensus on the best cell type for treating LSCD. Major findings of all these studies with special emphasis on substrates for culture and transplantation are systematically presented and discussed. Among the many potential cell types that still have not been used clinically, we conclude that two easily accessible autologous sources, epidermal stem cells and hair follicle-derived stem cells, are particularly strong candidates for future clinical trials. PMID:26343740

  16. Stem Cell Basics

    Science.gov (United States)

    ... Information Stem Cell Basics Stem Cell Basics: Introduction Stem Cell Information General Information Clinical Trials Funding Information Current Research Policy Glossary Site Map Stem Cell Basics Introduction: What are stem cells, and why ...

  17. The effect of temperature on the viability of human mesenchymal stem cells

    OpenAIRE

    Reissis, Yannis; García-Gareta, Elena; Korda, Michelle; Blunn, Gordon W.; Hua, Jia

    2013-01-01

    Introduction Impaction allograft with cement is a common technique used in revision hip surgeries for the last 20 years. However, its clinical results are inconsistent. Recent studies have shown that mesenchymal stem cells (MSCs) seeded onto allograft can enhance bone formation. This in vitro study investigates whether the increase in temperature related to the polymerisation of bone cement will affect the viability of human MSCs. Methods The viability of human MSCs was measured after incubat...

  18. Concise Review: Clinical Translation of Wound Healing Therapies Based on Mesenchymal Stem Cells

    OpenAIRE

    Jackson, Wesley M.; Nesti, Leon J.; Tuan, Rocky S.

    2011-01-01

    There is enormous worldwide demand for therapies to promote the efficient resolution of hard-to-heal wounds with minimal appearance of scarring. Recent in vitro studies with mesenchymal stem cells (MSCs) have identified numerous mechanisms by which these cells can promote the process of wound healing, and there is significant interest in the clinical translation of an MSC-based therapy to promote dermal regeneration. This review provides a systematic analysis of recent preclinical and clinica...

  19. Cancer stem cells in basic science and in translational oncology: can we translate into clinical application?

    OpenAIRE

    Schulenburg, Axel; Blatt, Katharina; Cerny-Reiterer, Sabine; Sadovnik, Irina; Herrmann, Harald; Marian, Brigitte; Grunt, Thomas W.; Zielinski, Christoph C.; Valent, Peter

    2015-01-01

    Since their description and identification in leukemias and solid tumors, cancer stem cells (CSC) have been the subject of intensive research in translational oncology. Indeed, recent advances have led to the identification of CSC markers, CSC targets, and the preclinical and clinical evaluation of the CSC-eradicating (curative) potential of various drugs. However, although diverse CSC markers and targets have been identified, several questions remain, such as the origin and evolution of CSC,...

  20. Cartilage Regeneration in Human with Adipose Tissue-Derived Stem Cells: Current Status in Clinical Implications

    Directory of Open Access Journals (Sweden)

    Jaewoo Pak

    2016-01-01

    Full Text Available Osteoarthritis (OA is one of the most common debilitating disorders among the elderly population. At present, there is no definite cure for the underlying causes of OA. However, adipose tissue-derived stem cells (ADSCs in the form of stromal vascular fraction (SVF may offer an alternative at this time. ADSCs are one type of mesenchymal stem cells that have been utilized and have demonstrated an ability to regenerate cartilage. ADSCs have been shown to regenerate cartilage in a variety of animal models also. Non-culture-expanded ADSCs, in the form of SVF along with platelet rich plasma (PRP, have recently been used in humans to treat OA and other cartilage abnormalities. These ADSCs have demonstrated effectiveness without any serious side effects. However, due to regulatory issues, only ADSCs in the form of SVF are currently allowed for clinical uses in humans. Culture-expanded ADSCs, although more convenient, require clinical trials for a regulatory approval prior to uses in clinical settings. Here we present a systematic review of currently available clinical studies involving ADSCs in the form of SVF and in the culture-expanded form, with or without PRP, highlighting the clinical effectiveness and safety in treating OA.

  1. Potential role of stem cells in severe spinal cord injury: current perspectives and clinical data

    Directory of Open Access Journals (Sweden)

    Paspala SA

    2012-09-01

    Full Text Available Syed AB Paspala,1,2 Sandeep K Vishwakarma,1 Tenneti VRK Murthy,2 Thiriveedi N Rao,2 Aleem A Khan11PAN Research Foundation, CARE, 2The Institute of Medical Sciences, Hyderabad, IndiaAbstract: Stem cell transplantation for spinal cord injury (SCI along with new pharmacotherapy research offers the potential to restore function and ease the associated social and economic burden in the years ahead. Various sources of stem cells have been used in the treatment of SCI, but the most convincing results have been obtained with neural progenitor cells in preclinical models. Although the use of cell-based transplantation strategies for the repair of chronic SCI remains the long sought after holy grail, these approaches have been to date the most successful when applied in the subacute phase of injury. Application of cell-based strategies for the repair and regeneration of the chronically injured spinal cord will require a combinational strategy that may need to include approaches to overcome the effects of the glial scar, inhibitory molecules, and use of tissue engineering strategies to bridge the lesion. Nonetheless, cell transplantation strategies are promising, and it is anticipated that the Phase I clinical trials of some form of neural stem cell-based approach in SCI will commence very soon.Keywords: stem cell therapy, regeneration, spinal cord injury, cell dosing, cell tracking

  2. Time-dependent effects of clinical predictors in unrelated hematopoietic stem cell transplantation.

    Science.gov (United States)

    Fuerst, Daniel; Mueller, Carlheinz; Beelen, Dietrich W; Neuchel, Christine; Tsamadou, Chrysanthi; Schrezenmeier, Hubert; Mytilineos, Joannis

    2016-02-01

    Hematopoietic stem cell transplantation is a multifactorial process. Some of the predictors exhibit time-dependent effects. We present a systematic analysis and description of selected clinical predictors influencing outcome in a time-dependent manner based on an analysis of registry data from the German Registry for Stem Cell Transplantation. A total of 14,951 patients with acute myeloid leukemia, acute lymphocytic leukemia, myelodysplastic syndrome and non-Hodgkin lymphoma transplanted with peripheral blood stem cells or bone marrow grafts were included. Multivariate Cox regression models were tested for time-dependent effects within each diagnosis group. Predictors not satisfying the proportional hazards assumption were modeled in a time-dependent manner, extending the Cox regression models. Similar patterns occurred in all diagnosis groups. Patients with a poor Karnofsky performance score (transplantation (HR 2.42, CI: 2.19-2.68; Ptransplant (HR: 0.81 CI: 0.75-0.88; Ptransplantation (HR 0.79, CI: 0.73-0.85; P<0.001), reversing to a significantly higher risk afterwards (HR 1.23, CI: 1.08-1.40; P=0.002). Integrating time dependency in regression models allows a more accurate description and quantification of clinical predictors to be made, which may help in risk assessment and patient counseling. PMID:26611475

  3. Stem-Cell Work Yielding New Approach to Disease: Induced Pluripotent Stem-Cell Research Soars, Spurring Dreams of Clinical Applications.

    Science.gov (United States)

    Mertz, Leslie

    2016-01-01

    Interest in stem cells escalated in 2006 when scientists figured out how to reprogram some specialized adult cells to assume a stem-cell-like state. Called induced pluripotent stem cells (iPSCs), these cells opened the door to a range of potential applications, including generating cells and tissues to replace those that are faulty or missing in patients with cancer, diabetes, cardiovascular disease, or other maladies (Figure 1). Visions of new treatments and even cures for debilitating and fatal illnesses proliferated, and some of that work is well under way (see "A Wealth of Research"). Now, ten years later, those visions are looking more like real possibilities as research moves from the lab to the clinic and expands toward a greater understanding of the basic science behind stem cells and its applications. PMID:27414628

  4. Human adult stem cells from diverse origins: an overview from multiparametric immunophenotyping to clinical applications.

    Science.gov (United States)

    Sousa, Bruna R; Parreira, Ricardo C; Fonseca, Emerson A; Amaya, Maria J; Tonelli, Fernanda M P; Lacerda, Samyra M S N; Lalwani, Pritesh; Santos, Anderson K; Gomes, Katia N; Ulrich, Henning; Kihara, Alexandre H; Resende, Rodrigo R

    2014-01-01

    Stem cells are known for their capacity to self-renew and differentiate into at least one specialized cell type. Mesenchymal stem cells (MSCs) were isolated initially from bone marrow but are now known to exist in all vascularized organ or tissue in adults. MSCs are particularly relevant for therapy due to their simplicity of isolation and cultivation. The International Society for Cellular Therapy (ISCT) has proposed a set of standards to define hMSCs for laboratory investigations and preclinical studies: adherence to plastic in standard culture conditions; in vitro differentiation into osteoblasts, adipocytes, and chondroblasts; specific surface antigen expression in which ≥95% of the cells express the antigens recognized by CD105, CD73, and CD90, with the same cells lacking (≤2% positive) the antigens CD45, CD34, CD14 or CD11b, CD79a or CD19, and HLA-DR. In this review we will take an historical overview of how umbilical cord blood, bone marrow, adipose-derived, placental and amniotic fluid, and menstrual blood stem cells, the major sources of human MSC, can be obtained, identified and how they are being used in clinical trials to cure and treat a very broad range of conditions, including heart, hepatic, and neurodegenerative diseases. An overview of protocols for differentiation into hepatocytes, cardiomyocytes, neuronal, adipose, chondrocytes, and osteoblast cells are highlighted. We also discuss a new source of stem cells, induced pluripotent stem cells (iPS cells) and some pathways, which are common to MSCs in maintaining their pluripotent state. PMID:24700575

  5. Hematopoietic stem cell transplantation for multiple sclerosis: is it a clinical reality?

    Science.gov (United States)

    Bakhuraysah, Maha M; Siatskas, Christopher; Petratos, Steven

    2016-01-01

    Hematopoietic stem cell transplantation (HSCT) is a treatment paradigm that has long been utilized for cancers of the blood and bone marrow but has gained some traction as a treatment paradigm for multiple sclerosis (MS). Success in the treatment of patients with this approach has been reported primarily when strict inclusion criteria are imposed that have eventuated a more precise understanding of MS pathophysiology, thereby governing trial design. Moreover, enhancing the yield and purity of hematopoietic stem cells during isolation along with the utility of appropriate conditioning agents has provided a clearer foundation for clinical translation studies. To support this approach, preclinical data derived from animal models of MS, experimental autoimmune encephalomyelitis, have provided clear identification of multipotent stem cells that can reconstitute the immune system to override the autoimmune attack of the central nervous system. In this review, we will discuss the rationale of HSCT to treat MS by providing the benefits and complications of the clinically relevant protocols, the varying graft types, and conditioning regimens. However, we emphasize that future trials based on HSCT should be focused on specific therapeutic strategies to target and limit ongoing neurodegeneration and demyelination in progressive MS, in the hope that such treatment may serve a greater catchment of patient cohorts with potentially enhanced efficiency and lower toxicity. Despite these future ambitions, a proposed international multicenter, randomized clinical trial of HSCT should be governed by the best standard care of treatment, whereby MS patients are selected upon strict clinical course criteria and long-term follow-up studies of patients from international registries are imposed to advocate HSCT as a therapeutic option in the management of MS. PMID:26772391

  6. Mesenchymal Stem Cells in Lipogems, a Reverse Story: from Clinical Practice to Basic Science.

    Science.gov (United States)

    Tremolada, Carlo; Ricordi, Camillo; Caplan, Arnold I; Ventura, Carlo

    2016-01-01

    The idea that basic science should be the starting point for modern clinical approaches has been consolidated over the years, and emerged as the cornerstone of Molecular Medicine. Nevertheless, there is increasing concern over the low efficiency and inherent costs related to the translation of achievements from the bench to the bedside. These burdens are also perceived with respect to the effectiveness of translating basic discoveries in stem cell biology to the newly developing field of advanced cell therapy or Regenerative Medicine. As an alternative paradigm, past and recent history in Medical Science provides remarkable reverse stories in which clinical observations at the patient's bedside have fed major advances in basic research which, in turn, led to consistent progression in clinical practice. Within this context, we discuss our recently developed method and device, which forms the core of a system (Lipogems) for processing of human adipose tissue solely with the aid of mild mechanical forces to yield a microfractured tissue product. PMID:27236668

  7. The therapeutic potential, challenges and future clinical directions of stem cells from the Wharton's jelly of the human umbilical cord.

    Science.gov (United States)

    Bongso, Ariff; Fong, Chui-Yee

    2013-04-01

    Mesenchymal stem cells (MSCs) from bone marrow, adult organs and fetuses face the disadvantages of invasive isolation, limited cell numbers and ethical constraints while embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) face the clinical hurdles of potential immunorejection and tumorigenesis respectively. These challenges have prompted interest in the study and evaluation of stem cells from birth-associated tissues. The umbilical cord (UC) has been the most popular. Hematopoietic stem cells (HSCs) harvested from cord blood have been successfully used for the treatment of hematopoietic diseases. Stem cell populations have also been reported in other compartments of the UC viz., amnion, subamnion, perivascular region, Wharton's jelly, umbilical blood vessel adventia and endothelium. Differences in stemness characteristics between compartments have been reported and hence derivation protocols using whole UC pieces containing all compartments yield mixed stem cell populations with varied characteristics. Stem cells derived directly from the uncontaminated Wharton's jelly (hWJSCs) appear to offer the best clinical utility because of their unique beneficial properties. They are non-controversial, can be harvested painlessly in abundance, proliferative, possess stemness properties that last several passages in vitro, multipotent, hypoimmunogenic and do not induce tumorigenesis even though they have some ESC markers. hWJSCs and its extracts (conditioned medium and lysate) also possess anti-cancer properties and support HSC expansion ex vivo. They are thus attractive autologous or allogeneic agents for the treatment of malignant and non-malignant hematopoietic and non-hematopoietic diseases. This review critically evaluates their therapeutic value, the challenges and future directions for their clinical application. PMID:23233233

  8. Induced pluripotent stem cells in Parkinson's disease: scientific and clinical challenges.

    Science.gov (United States)

    Xiao, Bin; Ng, Huck Hui; Takahashi, Ryosuke; Tan, Eng-King

    2016-07-01

    Induced pluripotent stem cells (iPSCs), which greatly circumvent the ethical issue of human embryonic stem cells (ESCs), can be induced to differentiate to dopaminergic (DA) neurons, and hence be used as a human disease model for Parkinson's disease (PD). iPSCs can be also utilised to probe the mechanism, and serve as an 'in vivo' platform for drug screening and for cell-replacement therapies. However, any clinical trial approaches should be extensively supported by validated robust biological evidence (based on previous experience with fetal mesencephalic transplantation), in particular, the production and selection of the 'ideal' neurons (functional units with no oncological risk), together with the careful screening of appropriate candidates (such as genetic carriers), with inbuilt safeguards (safety studies) in the evaluation and monitoring (functional neuroimaging of both DA and non-DA system) of trial subjects. While iPSCs hold great promise for PD, there are still numerous scientific and clinical challenges that need to be surmounted before any clinical application can be safely introduced. PMID:26833176

  9. Induced pluripotent stem cells in Parkinson's disease: scientific and clinical challenges

    Science.gov (United States)

    Xiao, Bin; Ng, Huck Hui; Takahashi, Ryosuke; Tan, Eng-King

    2016-01-01

    Induced pluripotent stem cells (iPSCs), which greatly circumvent the ethical issue of human embryonic stem cells (ESCs), can be induced to differentiate to dopaminergic (DA) neurons, and hence be used as a human disease model for Parkinson's disease (PD). iPSCs can be also utilised to probe the mechanism, and serve as an ‘in vivo’ platform for drug screening and for cell-replacement therapies. However, any clinical trial approaches should be extensively supported by validated robust biological evidence (based on previous experience with fetal mesencephalic transplantation), in particular, the production and selection of the ‘ideal’ neurons (functional units with no oncological risk), together with the careful screening of appropriate candidates (such as genetic carriers), with inbuilt safeguards (safety studies) in the evaluation and monitoring (functional neuroimaging of both DA and non-DA system) of trial subjects. While iPSCs hold great promise for PD, there are still numerous scientific and clinical challenges that need to be surmounted before any clinical application can be safely introduced. PMID:26833176

  10. Stem cell therapy for type 1 diabetes mellitus: a review of recent clinical trials

    Directory of Open Access Journals (Sweden)

    Couri Carlos

    2009-10-01

    Full Text Available Abstract Stem cell therapy is one of the most promising treatments for the near future. It is expected that this kind of therapy can ameliorate or even reverse some diseases. With regard to type 1 diabetes, studies analyzing the therapeutic effects of stem cells in humans began in 2003 in the Hospital das Clínicas of the Faculty of Medicine of Ribeirão Preto - SP USP, Brazil, and since then other centers in different countries started to randomize patients in their clinical trials. Herein we summarize recent data about beta cell regeneration, different ways of immune intervention and what is being employed in type 1 diabetic patients with regard to stem cell repertoire to promote regeneration and/or preservation of beta cell mass. The Diabetes Control and Complications Trial (DCCT was a 7-year longitudinal study that demonstrated the importance of the intensive insulin therapy when compared to conventional treatment in the development of chronic complications in patients with type 1 diabetes mellitus (T1DM. This study also demonstrated another important issue: there is a reverse relationship between C-peptide levels (endogenous indicator of insulin secretion chronic complications - that is, the higher the C-peptide levels, the lower the incidence of nephropathy, retinopathy and hypoglycemia. From such data, beta cell preservation has become an additional target in the management of T1DM 1.

  11. Clinical implications of microRNAs in liver cancer stem cells

    Institute of Scientific and Technical Information of China (English)

    Stella Chai; Stephanie Ma

    2013-01-01

    The prognosis of patients diagnosed with hepatocellular carcinoma (HCC) is often dismal,mainly due to late presentation,high recurrence rate,and frequent resistance to chemotherapy and radiotherapy.Accumulating evidence on the differential microRNA (miRNA) expression patterns between non-tumor and HCC tissues or between liver cancer stem cells (CSCs) and non-CSC subsets and the significant clinical implications of these differences suggest that miRNAs are a promising,non-invasive marker for the prognosis and diagnosis of the disease.This perspective article summarizes the current knowledge of miRNAs in liver CSCs and highlights the need for further investigations of the role of miRNAs in regulating liver CSC subsets for possible future clinical applications.

  12. Stem Cell Transplantation As A Dynamical System: Are Clinical Outcomes Deterministic?

    Directory of Open Access Journals (Sweden)

    Amir A Toor

    2014-12-01

    Full Text Available Outcomes in stem cell transplantation (SCT are modeled using probability theory. However the clinical course following SCT appears to demonstrate many characteristics of dynamical systems, especially when outcomes are considered in the context of immune reconstitution. Dynamical systems tend to evolve over time according to mathematically determined rules. Characteristically, the future states of the system are predicated on the states preceding them, and there is sensitivity to initial conditions. In SCT, the interaction between donor T cells and the recipient may be considered as such a system in which, graft source, conditioning and early immunosuppression profoundly influence immune reconstitution over time. This eventually determines clinical outcomes, either the emergence of tolerance or the development of graft versus host disease. In this paper parallels between SCT and dynamical systems are explored and a conceptual framework for developing mathematical models to understand disparate transplant outcomes is proposed.

  13. Comparison of different culture conditions for human mesenchymal stromal cells for clinical stem cell therapy

    DEFF Research Database (Denmark)

    Haack-Sorensen, M.; Friis, T.; Bindslev, L.;

    2008-01-01

    used for MSC cultivation in animal studies simulating clinical stem cell therapy. MATERIAL AND METHODS: Human mononuclear cells (MNCs) were isolated from BM aspirates by density gradient centrifugation and cultivated in a GMP-accepted medium (EMEA medium) or in one of four other media. RESULTS: FACS...... compliant medium for MSC cultivation, expansion and differentiation. The expanded and differentiated MSCs can be used in autologous mesenchymal stromal cell therapy in patients with ischaemic heart disease Udgivelsesdato: 2008......OBJECTIVE: Mesenchymal stromal cells (MSCs) from adult bone marrow (BM) are considered potential candidates for therapeutic neovascularization in cardiovascular disease. When implementing results from animal trials in clinical treatment, it is essential to isolate and expand the MSCs under...

  14. Experimental in-vitro bone cements disintegration with ultrasonic pulsating water jet for revision arthroplasty

    OpenAIRE

    S. Hloch; Foldyna, J.; Pude, F.; Kloc, J.; M. Zeleňák; Hvizdoš, P.; Monka, P.; Smolko, I.; Ščučka, J. (Jiří); Kozak, D.; A. Sedmak; Mihalčinová, E.

    2015-01-01

    The paper deals with the study of using the selective property of ultrasonic pulsating water jet for the disintegration of the interface created by bone cement between cemented femoral stem and trabecular bone tissue as a potential technique for revision arthroplasty. Six types of commercial bone cements based on Polymethyl Methacrylate were used for investigation. The cements were mixed using the DePuy - SmartMix® CTS / vacuum mixing bowl. Mechanical properties of hardened bone cements were ...

  15. Clinical outcomes after autologous haematopoietic stem cell transplantation in patients with progressive multiple sclerosis

    Institute of Scientific and Technical Information of China (English)

    XU Juan; JI Bing-xin; SU Li; DONG Hui-qing; SUN Xue-jing; LIU Cong-yan

    2006-01-01

    Background Multiple sclerosis (MS) is a continuously disabling disease and it is unresponsive to high dose steroid and immunomodulation with disease progression. The autologous haematopoietic stem cell transplantation (ASCT) has been introduced in the treatment of refractory forms of multiple sclerosis. In this study, the clinical outcomes followed by ASCT were evaluated for patients with progressive MS.Methods Twenty-two patients with secondary progressive MS were treated with ASCT. Peripheral blood stem cells were obtained by leukapheresis after mobilization with granulocyte colony stimulating factor. Etoposide,melphalan, carmustin and cytosine arabinoside were administered as conditioning regimen. Outcomes were evaluated by the expanded disability status scale and progression free survival. No maintenance treatment was administered during a median follow-up of 39 months (range, 6 to 59 months).Results No death occurred following the treatment. The overall confirmed progression free survival rate was77% up to 59 months after transplantation which was significantly higher compared with pre-transplantation (P=0.000). Thirteen patients (59%) had remarkable improvement in neurological manifestations, four (18%)stabilized their disability status and five (23%) showed clinical recurrence of active symptoms.Conclusions ASCT as a therapy is safe and available. It can improve or stabilize neurological manifestations in most patients with progressive MS following failure of conventional therapy.

  16. Clinical Application of Mesenchymal Stem Cells and Novel Supportive Therapies for Oral Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Miguel Padial-Molina

    2015-01-01

    Full Text Available Bone regeneration is often needed prior to dental implant treatment due to the lack of adequate quantity and quality of the bone after infectious diseases, trauma, tumor, or congenital conditions. In these situations, cell transplantation technologies may help to overcome the limitations of autografts, xenografts, allografts, and alloplastic materials. A database search was conducted to include human clinical trials (randomized or controlled and case reports/series describing the clinical use of mesenchymal stem cells (MSCs in the oral cavity for bone regeneration only specifically excluding periodontal regeneration. Additionally, novel advances in related technologies are also described. 190 records were identified. 51 articles were selected for full-text assessment, and only 28 met the inclusion criteria: 9 case series, 10 case reports, and 9 randomized controlled clinical trials. Collectively, they evaluate the use of MSCs in a total of 290 patients in 342 interventions. The current published literature is very diverse in methodology and measurement of outcomes. Moreover, the clinical significance is limited. Therefore, the use of these techniques should be further studied in more challenging clinical scenarios with well-designed and standardized RCTs, potentially in combination with new scaffolding techniques and bioactive molecules to improve the final outcomes.

  17. Influence of the tibial stem design on bone density after cemented total knee arthroplasty: a prospective seven-year follow-up study.

    Science.gov (United States)

    Hernandez-Vaquero, Daniel; Garcia-Sandoval, Manuel A; Fernandez-Carreira, Jose M; Gava, Richard

    2008-02-01

    We prospectively measured the changes in bone mineral density (BMD) in the proximal tibia of 20 total knee arthroplasties, ten with cruciform stems and ten with cylindrical stems. The measurements were made one, four and seven years after surgery. We observed a uniform density decrease in three regions of interest from one to seven years of follow-up. Cylindrical stems showed an asymmetrical density decrease between the three regions of interest, with no change in the central region, a slight decrease in the lateral region, and large decrease in the medial region. Multivariate analysis with general linear model showed the stem type factor as statistically significant for medial region of interest (p = 0.006). The cylindrical stem produces heterogeneous BMD changes under the tibial platform in knee arthroplasties, and this could be a potential risk factor for asymmetrical subsidence of this component. PMID:17115154

  18. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1994-12-01

    Full Text Available During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production, pipe corrosion and expensive well repairs. Cementing temperature conditions are important because bot-tomhole circulating temperatures affect slurry thickening time, arheology, set time and compressive strength development. Knowing the actual temperature which cement encounters during placement allows the selection of proper cementing materials for a specific application. Slurry design is affected by well depth, bottom hole circulating temperature and static temperature, type or drilling fluid, slurry density, pumping time, quality of mix water, fluid loss control, flow regime, settling and free water, quality of cement, dry or liquid additives, strength development, and quality of the lab cement testing and equipment. Most Portland cements and Class J cement have shown suitable performances in geot-hermal wells. Cement system designs for geothermal wells differ from those for conventional high temperature oil and gas wells in the exclusive use of silica flour instead of silica sand, and the avoidance of fly ash as an extender. In this paper, Portland cement behaviour at high temperatures is described. Cement slurry and set cement properties are also described. Published in literature, the composition of cement slurries which were tested in geothermal conditions and which obtained required compressive strength and water permeability are listed. As a case of our practice geothermal wells Velika Ciglena-1 and Velika Ciglena-la are described.

  19. Application of glass ionomer cements in restorative dentistry.

    OpenAIRE

    Rajesh P; Kamath M

    1999-01-01

    Dentistry was marked with radical changes in clinical restorative procedures. If the inherent characteristic of the ionomer cement was examined, it becomes very clear to the researcher as well as the dentist, that no other material has had an impact as comparable to glass ionomer cements on restorative dentistry. This scientific paper highlights the clinical applications of the cement in restorative dentistry. Glass ionomer cements are bioactive, by forming permanent adhesive bonds to dentin ...

  20. Stem cell bioprocess engineering towards cGMP production and clinical applications

    OpenAIRE

    Sart, Sébastien; Schneider, Yves-Jacques; Li, Yan; Agathos, Spiros N.

    2014-01-01

    Stem cells, including mesenchymal stem cells and pluripotent stem cells, are becoming an indispensable tool for various biomedical applications including drug discovery, disease modeling, and tissue engineering. Bioprocess engineering, targeting large scale production, provides a platform to generate a controlled microenvironment that could potentially recreate the stem cell niche to promote stem cell proliferation or lineage-specific differentiation. This survey aims at defining the characte...

  1. Biological and clinical implications of cancer stem cells in primary brain tumors

    Directory of Open Access Journals (Sweden)

    RuggeroDe Maria

    2013-01-01

    Full Text Available Despite therapeutic advances, glioblastoma multiforme (GBM remains a lethal disease. The infiltrative nature of this disease and the presence of a cellular population resistant to current medical treatments account for the poor prognosis of these patients. Growing evidence indicates the existence of a fraction of cancer cells sharing the functional properties of adult stem cells, including self-renewal and a greater ability to escape chemo-radiotherapy-induced death stimuli. Therefore, these cells are commonly defined as cancer stem cells (GBM-SCs. The initial GBM-SC concept has been challenged, and refined according to the emerging molecular taxonomy of GBM. This allowed to postulate the existence of multiple CSC types, each one driving a given molecular entity. Furthermore, it is becoming increasingly clear that GBM-SCs thrive through a dynamic and bidirectional interaction with the surrounding microenvironment. In this article, we discuss recent advances in GBM-SC biology, mechanisms through which these cells adapt to hostile conditions, pharmacological strategies for selectively killing GBM-SCs, and how novel CSC-associated endpoints have been investigated in the clinical setting.

  2. Concise review: optimizing expansion of bone marrow mesenchymal stem/stromal cells for clinical applications.

    Science.gov (United States)

    Hoch, Allison I; Leach, J Kent

    2014-05-01

    Bone marrow-derived mesenchymal stem/stromal cells (MSCs) have demonstrated success in the clinical treatment of hematopoietic pathologies and cardiovascular disease and are the focus of treating other diseases of the musculoskeletal, digestive, integumentary, and nervous systems. However, during the requisite two-dimensional (2D) expansion to achieve a clinically relevant number of cells, MSCs exhibit profound degeneration in progenitor potency. Proliferation, multilineage potential, and colony-forming efficiency are fundamental progenitor properties that are abrogated by extensive monolayer culture. To harness the robust therapeutic potential of MSCs, a consistent, rapid, and minimally detrimental expansion method is necessary. Alternative expansion efforts have exhibited promise in the ability to preserve MSC progenitor potency better than the 2D paradigm by mimicking features of the native bone marrow niche. MSCs have been successfully expanded when stimulated by growth factors, under reduced oxygen tension, and in three-dimensional bioreactors. MSC therapeutic value can be optimized for clinical applications by combining system inputs to tailor culture parameters for recapitulating the niche with probes that nondestructively monitor progenitor potency. The purpose of this review is to explore how modulations in the 2D paradigm affect MSC progenitor properties and to highlight recent efforts in alternative expansion techniques. PMID:24682286

  3. Clinical Relevance of Natural Killer Cells Following Hematopoietic Stem Cell Transplantation

    Directory of Open Access Journals (Sweden)

    Jeanne M Palmer, Kamalakannan Rajasekaran, Monica S Thakar, Subramaniam Malarkannan

    2013-01-01

    Full Text Available Natural killer (NK cells are one of the first cells to recover following allogeneic hematopoietic stem cell transplantation (HSCT, and are believed to play an important role in facilitating engraftment or preventing post-transplant infection and tumor recurrence. Recent studies have provided novel insights into the mechanisms by which NK cells mediate these highly clinically relevant immunological functions. In particular, the ability of NK cells to reduce the risk of graft versus host disease (GVHD and increase the graft versus leukemia effect (GVL in the setting of human leukocyte antigen (HLA-haploidentical HSCT highlights their clinical potentials. NK cells also mediate anti-viral protection, in particular against cytomegalovirus (CMV, an infection that causes significant morbidity and mortality following transplant. Another crucial function of NK cells is providing protection against bacterial infections at the mucosal barriers. NK cells achieve this by promoting anti-microbial defenses and regeneration of epithelial cells. These recent exciting findings provide a strong basis for the formulation of novel NK cell-based immunotherapies. In this review, we summarize the recent advances related to the mechanisms, functions, and future clinical prospects of NK cells that can impact post-transplant outcomes.

  4. Basic Science and Clinical Application of Stem Cells in Veterinary Medicine

    Science.gov (United States)

    Ribitsch, I.; Burk, J.; Delling, U.; Geißler, C.; Gittel, C.; Jülke, H.; Brehm, W.

    Stem cells play an important role in veterinary medicine in different ways. Currently several stem cell therapies for animal patients are being developed and some, like the treatment of equine tendinopathies with mesenchymal stem cells (MSCs), have already successfully entered the market. Moreover, animal models are widely used to study the properties and potential of stem cells for possible future applications in human medicine. Therefore, in the young and emerging field of stem cell research, human and veterinary medicine are intrinsically tied to one another. Many of the pioneering innovations in the field of stem cell research are achieved by cooperating teams of human and veterinary medical scientists.

  5. When is The Best Time of Stem Cell Transplantation for Treating Acute Myocardial Infarction——A Brief Meta-analysis of Current Clinic Trials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The best time of stem cells transplantation for treating acute myocardial infarction (AMI) is still to be followed with interest and a focus issue for clinical cardiologist. A brief meta-analysis of clinical trials about timing-window and therapeutic effects of stem cell transplantation for treating AMI will be made out in this article.

  6. Safety and function of a new clinical intracerebral microinjection instrument for stem cells and therapeutics examined in the Göttingen minipig

    DEFF Research Database (Denmark)

    Bjarkam, Carsten R; GLUD, AN; Margolin, Lee;

    2010-01-01

    Safety and function of a new clinical intracerebral microinjection instrument for stem cells and therapeutics examined in the Göttingen minipig......Safety and function of a new clinical intracerebral microinjection instrument for stem cells and therapeutics examined in the Göttingen minipig...

  7. Stem cells from foetal adnexa and fluid in domestic animals: an update on their features and clinical application.

    Science.gov (United States)

    Iacono, E; Rossi, B; Merlo, B

    2015-06-01

    Over the past decade, stem cell research has emerged as an area of major interest for its potential in regenerative medicine applications. This is in constant need of new cell sources to conceive regenerative medicine approaches for diseases that are still without therapy. Scientists drew the attention towards alternative sources such as foetal adnexa and fluid, as these sources possess many advantages: first of all, cells can be extracted from discarded foetal material and it is non-invasive and inexpensive for the patient; secondly, abundant stem cells can be obtained; and finally, these stem cell sources are free from ethical considerations. Cells derived from foetal adnexa and fluid preserve some of the characteristics of the primitive embryonic layers from which they originate. Many studies have demonstrated the differentiation potential in vitro and in vivo towards mesenchymal and non-mesenchymal cell types; in addition, the immune-modulatory properties make these cells a good candidate for allo- and xenotransplantation. Naturally occurring diseases in domestic animals can be more ideal as disease model of human genetic and acquired diseases and could help to define the potential therapeutic use efficiency and safety of stem cells therapies. This review offers an update on the state of the art of characterization of domestic animals' MSCs derived from foetal adnexa and fluid and on the latest findings in pre-clinical or clinical setting of the stem cell populations isolated from these sources. PMID:25703812

  8. Human Induced Pluripotent Stem Cells from Basic Research to Potential Clinical Applications in Cancer

    Directory of Open Access Journals (Sweden)

    Teresa de Souza Fernandez

    2013-01-01

    Full Text Available The human induced pluripotent stem cells (hiPSCs are derived from a direct reprogramming of human somatic cells to a pluripotent stage through ectopic expression of specific transcription factors. These cells have two important properties, which are the self-renewal capacity and the ability to differentiate into any cell type of the human body. So, the discovery of hiPSCs opens new opportunities in biomedical sciences, since these cells may be useful for understanding the mechanisms of diseases in the production of new diseases models, in drug development/drug toxicity tests, gene therapies, and cell replacement therapies. However, the hiPSCs technology has limitations including the potential for the development of genetic and epigenetic abnormalities leading to tumorigenicity. Nowadays, basic research in the hiPSCs field has made progress in the application of new strategies with the aim to enable an efficient production of high-quality of hiPSCs for safety and efficacy, necessary to the future application for clinical practice. In this review, we show the recent advances in hiPSCs’ basic research and some potential clinical applications focusing on cancer. We also present the importance of the use of statistical methods to evaluate the possible validation for the hiPSCs for future therapeutic use toward personalized cell therapies.

  9. Concise Review: Preleukemic Stem Cells: Molecular Biology and Clinical Implications of the Precursors to Leukemia Stem Cells

    OpenAIRE

    Pandolfi, Ashley; Barreyro, Laura; Steidl, Ulrich

    2013-01-01

    Despite the established use of poly-chemotherapy, relapse continues to be the most common cause of death in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). The therapeutic elimination of all leukemia stem cells (LSC) and pre-LSC will be essential for achieving lasting cures. This article reviews recent and ongoing advances in understanding the roles of pre-LSC, and the aberrations that lead to pre-LSC formation and subsequent LSC transformation.

  10. Markers of stem cells in human ovarian granulosa cells: is there a clinical significance in ART?

    Directory of Open Access Journals (Sweden)

    Varras Michail

    2012-11-01

    Full Text Available Abstract Background The purpose of the study was to determine the incidence of gene expression of Oct-4 and DAZL, which are typical markers for stem cells, in human granulosa cells during ovarian stimulation in women with normal FSH levels undergoing IVF or ICSI and to discover any clinical significance of such expression in ART. Methods Twenty one women underwent ovulation induction for IVF or ICSI and ET with standard GnRH analogue-recombinant FSH protocol. Infertility causes were male and tubal factor. Cumulus–mature oocyte complexes were denuded separately and granulosa cells were analyzed for each patient separately using quantitative reverse-transcription–polymerase chain reaction analysis for Oct-4 and DAZL gene expression with G6PD gene as internal standard. Results G6PD and Oct-4 mRNA was detected in the granulosa cells in 47.6% (10/21. The median of Oct-4 mRNA/G6PD mRNA was 1.75 with intra-quarteral range from 0.10 to 98.21. The OCT-4 mRNA expression was statistically significantly correlated with the number of oocytes retrieved; when the Oct-4 mRNA expression was higher, then more than six oocytes were retrieved (p=0.037, Wilcoxon rank-sum. No detection of DAZL mRNA was found in granulosa cells. There was no additional statistically significant correlation between the levels of Oct-4 expression and FSH basal levels or estradiol peak levels or dosage of FSH for ovulation induction. No association was found between the presence or absence of Oct-4 mRNA expression in granulosa cells and ovarian response to gonadotropin stimulation. Also, no influence on pregnancy was observed between the presence or absence of Oct-4 mRNA expression in granulosa cells or to its expression levels accordingly. Conclusions Expression of OCT-4 mRNA, which is a typical stem cell marker and absence of expression of DAZL mRNA, which is a typical germ cell marker, suggest that a subpopulation of luteinized granulosa cells in healthy ovarian follicles (47

  11. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  12. Low pH Cements

    International Nuclear Information System (INIS)

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit ≤ 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio ≤ 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  13. Injectable citrate-modified Portland cement for use in vertebroplasty

    OpenAIRE

    Wynn-Jones, Gareth; Shelton, Richard M.; Hofmann, Michael P

    2014-01-01

    The injectability of Portland cement (PC) with several citrate additives was investigated for use in clinical applications such as vertebroplasty (stabilization of a fractured vertebra with bone cement) using a syringe. A 2-wt % addition of sodium or potassium citrate with PC significantly improved cement injectability, decreased cement setting times from over 2 h to below 25 min, while increasing the compressive strength to a maximum of 125 MPa. Zeta-potential measurements indicated that the...

  14. Analysis of Femoral Components of Cemented Total Hip- Arthroplasty

    CERN Document Server

    Singh, Shantanu

    2014-01-01

    In cemented Total Hip Arthroplasty (THA), material chosen for femoral stem and cross section of stem itself, proved to be critical parameters for, stress distribution in the femoral components, interfacial stresses and micro movements. Titanium alloy (Ti6Al4V), when used as a material for femoral stem, recorded large displacement as compared to Chromium alloy (CoCrMo) stems. This large displacement in case of Ti6Al4V caused the stem to bend inside the cement mantle, thus destroying it. Thus, CoCrMo proved to be a better in cemented THA. Failure in THA may occur at cement-stem or cement-bone interface, thus interfacial stresses and micro movements were analysed in the present study. Comparison between trapezium and circular cross section showed that, femoral stem with trapezium cross section underwent lesser amount of sliding and debonding, at both interfaces, as compared to circular cross section. Moreover, trapezium cross section also generated lower peak stresses in femoral stem and cortical femur. The pres...

  15. Translation of Human-Induced Pluripotent Stem Cells: From Clinical Trial in a Dish to Precision Medicine.

    Science.gov (United States)

    Sayed, Nazish; Liu, Chun; Wu, Joseph C

    2016-05-10

    The prospect of changing the plasticity of terminally differentiated cells toward pluripotency has completely altered the outlook for biomedical research. Human-induced pluripotent stem cells (iPSCs) provide a new source of therapeutic cells free from the ethical issues or immune barriers of human embryonic stem cells. iPSCs also confer considerable advantages over conventional methods of studying human diseases. Since its advent, iPSC technology has expanded with 3 major applications: disease modeling, regenerative therapy, and drug discovery. Here we discuss, in a comprehensive manner, the recent advances in iPSC technology in relation to basic, clinical, and population health. PMID:27151349

  16. Clinical Trial Design for Testing the Stem Cell Model for the Prevention and Treatment of Cancer

    OpenAIRE

    Wicha, Max S.; Madhuri Kakarala; Reddy, Rishindra M.

    2011-01-01

    The cancer stem cell model introduces new strategies for the prevention and treatment of cancers. In cancers that appear to follow the stem cell model, pathways such as Wnt, Notch and Hedgehog may be targeted with natural compounds such as curcumin or drugs to reduce the risk of initiation of new tumors. Disease progression of established tumors could also potentially be inhibited by targeting the tumorigenic stem cells alone, rather than aiming to reduce overall tumor size. These new approac...

  17. Stem Cells in Skin Regeneration, Wound Healing, and Their Clinical Applications

    OpenAIRE

    Nkemcho Ojeh; Irena Pastar; Marjana Tomic-Canic; Olivera Stojadinovic

    2015-01-01

    The skin is the largest organ of the body and has an array of functions. Skin compartments, epidermis, and hair follicles house stem cells that are indispensable for skin homeostasis and regeneration. These stem cells also contribute to wound repair, resulting in restoration of tissue integrity and function of damaged tissue. Unsuccessful wound healing processes often lead to non-healing wounds. Chronic wounds are caused by depletion of stem cells and a variety of other cellular and molecular...

  18. Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations

    OpenAIRE

    Brad B Swelstad; Kerr, Candace L.

    2009-01-01

    Brad B Swelstad, Candace L KerrInstitute for Cell Engineering, Department of Obstetrics and Gynecology, Johns Hopkins University, Baltimore, MA, USAAbstract: Pluripotent stem cells have been derived from various embryonic, fetal and adult sources. Embryonic stem cells (ESCs) and parthenogenic ESCs (pESCs) are derived from the embryo proper while embryonic germ cells (EGCs), embryonal carcinoma cells (ECCs), and germ-line stem cells (GSC) are produced from germ cells. ECCs were the first pluri...

  19. Clinical and immunologic outcome of patients with cartilage hair hypoplasia after hematopoietic stem cell transplantation.

    Science.gov (United States)

    Bordon, Victoria; Gennery, Andrew R; Slatter, Mary A; Vandecruys, Els; Laureys, Genevieve; Veys, Paul; Qasim, Waseem; Waseem, Qasim; Friedrich, Wilhelm; Wulfraat, Nico M; Scherer, Franziska; Cant, Andrew J; Fischer, Alain; Cavazzana-Calvo, Marina; Cavazanna-Calvo, Marina; Bredius, Robbert G M; Notarangelo, Luigi D; Mazzolari, Evelina; Neven, Benedicte; Güngör, Tayfun; Tayfun, Güngör

    2010-07-01

    Cartilage-hair hypoplasia (CHH) is a rare autosomal recessive disease caused by mutations in the RMRP gene. Beside dwarfism, CHH has a wide spectrum of clinical manifestations including variable grades of combined immunodeficiency, autoimmune complications, and malignancies. Previous reports in single CHH patients with significant immunodeficiencies have demonstrated that allogeneic hematopoietic stem cell transplantation (HSCT) is an effective treatment for the severe immunodeficiency, while growth failure remains unaffected. Because long-term experience in larger cohorts of CHH patients after HSCT is currently unreported, we performed a European collaborative survey reporting on 16 patients with CHH and immunodeficiency who underwent HSCT. Immune dysregulation, lymphoid malignancy, and autoimmunity were important features in this cohort. Thirteen patients were transplanted in early childhood ( approximately 2.5 years). The other 3 patients were transplanted at adolescent age. Of 16 patients, 10 (62.5%) were long-term survivors, with a median follow-up of 7 years. T-lymphocyte numbers and function have normalized, and autoimmunity has resolved in all survivors. HSCT should be considered in CHH patients with severe immunodeficiency/autoimmunity, before the development of severe infections, major organ damage, or malignancy might jeopardize the outcome of HSCT and the quality of life in these patients. PMID:20375313

  20. Stem system

    Directory of Open Access Journals (Sweden)

    Shajmardanova L.R.

    2008-01-01

    Full Text Available The article shows the stem cells from the point of view of systemic anatomy, where they are united into an entire stem system. This integration shows various advantages for better understanding the stem cells role in the body. Authors, considering functions and action mechanism of stem cells, phylogeny, ontogeny, regulation of functions, explain the base for stem cells system existance. The definition and terminology, age peculiarities, relationship with other systems of organs and differences are offered. The theoretical proof of primary-integrative role of stem system is provided for all other systems in body. Of particular importance is the role of stem system as a link between neural and endocrine systems. The work helps to sistematize data on investigations of stem cells, their entire-system perception, that will ease the goals determining for further research and their clinical use.

  1. High-dose immunosuppression and hematopoietic stem cell transplantation in autoimmune disease: clinical review.

    Science.gov (United States)

    Openshaw, Harry; Nash, Richard A; McSweeney, Peter A

    2002-01-01

    Since 1996, a number of investigators have carried out phase I-II studies of high-dose immunosuppression with autologous hematopoietic stem cell transplantation (HSCT) in autoimmune diseases. Most of this activity has been in studies of multiple sclerosis (MS), systemic sclerosis (SSc), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and juvenile idiopathic arthritis (JIA). Supported by animal models of antigen-induced autoimmunity, the rationale of HSCT is to time-shift the clinical autoimmunity to an earlier period, restoring self-tolerance. Even with the considerable experience of more than 200 transplantations since 1996, it is difficult to judge the optimal approach. This difficulty is in part because of the multiplicity of centers and protocols and the variability in patient eligibility and assessment, the extent of T-cell depletion, and the intensity of the preparatory regimens used. Other than that found in RA, treatment-related mortality has been higher than expected: 17% in SSc (with an additional 10% mortality from progressive disease), 13% in SLE, 13% in JIA, and 8% in MS. Protocol changes to improve safety have been instituted. These changes include the avoidance of high-dose rabbit antithymocyte serum in patients who received T-cell-depleted grafts, use of corticosteroids with granulocyte colony-stimulating factor during stem cell mobilization and as prophylaxis for the engraftment syndrome in MS, lung radiation shielding in SSc, and multiple precautions against the macrophage activation syndrome in JIA. Responses to primary and secondary endpoints have been seen, and there is a consensus among investigators and regulatory bodies that the time has come for randomized phase II-III studies. Each disease presents distinct difficulties: in MS, restriction of eligibility to patients with active inflammatory disease; in SSc, formulation of cardiopulmonary eligibility criteria to decrease risk; in SLE, judgment of whether HSCT adds any

  2. Aseptic loosening of the femoral implant after cemented total hip arthroplasty in dogs: 11 cases in 10 dogs (1991-1995)

    International Nuclear Information System (INIS)

    Objective-To determine clinical signs, radiographic findings, results of surgical management, and potential causes of aseptic loosening of the femoral implant (ALFI) in dogs that have undergone cemented total hip arthroplasty (THA). Design-Retrospective study. Animals-11 cases of ALFI in 10 dogs. Procedure-Medical records of all dogs undergoing THA revision surgery were reviewed. Only dogs with ALFI were included. The prosthesis and cement were removed by creating a longitudinal osteotomy of the cranial femoral cortex. Postoperative radiographs of all dogs that underwent THA during the study period were reviewed. Results-The most common clinical sign was intermittent, subtle. or non-weight-bearing lameness. On radiographs obtained after THA, contact of the distal stem tip with cortical endosteum was evident in all dogs. Radiographic changes at the time of diagnosis of ALFI included asymmetric periosteal reaction along the femoral diaphysis, radiolucent lines between the prosthesis and cement, altered implant position, and femoral fracture. Surgical revision yielded good or excellent results in 9 cases. In 1 dog. the implant became infected; in another, aseptic loosening recurred. Aseptic loosening was significantly more common in dogs in which there was contact between the distal stem tip and cortical endosteum than in dogs in which there was no contact. Clinical Implications-ALFI is an uncommon, but important, complication of THA, and radiography is warranted in dogs with clinical signs of ALFI. Initial centering of the prosthetic stem within the femoral shaft may reduce the incidence of ALFI

  3. Human Adipose-Derived Mesenchymal Stem Cells in Cell Therapy: Safety and Feasibility in Different "Hospital Exemption" Clinical Applications

    OpenAIRE

    Vériter, Sophie; André, Wivine; Aouassar, Najima; Poirel, Hélène Antoine; Lafosse, Aurore; Docquier, Pierre-Louis; Dufrane, Denis

    2015-01-01

    Based on immunomodulatory, osteogenic, and pro-angiogenic properties of adipose-derived stem cells (ASCs), this study aims to assess the safety and efficacy of ASC-derived cell therapies for clinical indications. Two autologous ASC-derived products were proposed to 17 patients who had not experienced any success with conventional therapies: (1) a scaffold-free osteogenic three-dimensional graft for the treatment of bone non-union and (2) a biological dressing for dermal reconstruction of non-...

  4. Human Adipose-Derived Mesenchymal Stem Cells in Cell Therapy: Safety and Feasibility in Different "Hospital Exemption" Clinical Applications.

    OpenAIRE

    Veriter, Sophie; André, Wivine; Aouassar, Najima; Poirel, Hélène; Lafosse, Aurore; Docquier, Pierre-Louis; Dufrane, Denis

    2015-01-01

    Based on immunomodulatory, osteogenic, and pro-angiogenic properties of adipose-derived stem cells (ASCs), this study aims to assess the safety and efficacy of ASC-derived cell therapies for clinical indications. Two autologous ASC-derived products were proposed to 17 patients who had not experienced any success with conventional therapies: (1) a scaffold-free osteogenic three-dimensional graft for the treatment of bone non-union and (2) a biological dressing for dermal reconstruction of non-...

  5. Benefits, risks and ethical considerations in translation of stem cell research to clinical applications in Parkinson's disease

    OpenAIRE

    Master, Zubin; McLeod, Marcus; Mendez, Ivar

    2007-01-01

    Stem cells are likely to be used as an alternate source of biological material for neural transplantation to treat Parkinson's disease in the not too distant future. Among the several ethical criteria that must be fulfilled before proceeding with clinical research, a favourable benefit to risk ratio must be obtained. The potential benefits to the participant and to society are evaluated relative to the risks in an attempt to offer the participants a reasonable choice. Through examination of p...

  6. Efficient and scalable expansion of human pluripotent stem cells under clinically compliant settings: a view in 2013

    OpenAIRE

    Wang, Ying; Cheng, Linzhao; Gerecht, Sharon

    2013-01-01

    Human pluripotent stem cells (hPSCs) hold great promise for revolutionizing regenerative medicine for their potential applications in disease modeling, drug discovery, and cellular therapy. Many their applications require robust and scalable expansion of hPSCs, even under settings compliant to good clinical practices. Rapid evolution of media and substrates provided safer and more defined culture conditions for long-term expansion of undifferentiated hPSCs in either adhesion or suspension. Wi...

  7. Study on genotoxicity, oxidative stress biomarkers and clinical symptoms in workers of an asbestos-cement factory.

    Science.gov (United States)

    Afaghi, Azam; Oryan, Shahrbanoo; Rahzani, Kobra; Abdollahi, Mohammad

    2015-01-01

    The purpose of the present study was to investigate whether the markers of oxidative stress could be altered in workers exposed to asbestos. A comparative cross-sectional research was conducted in a group of 50 subjects exposed to asbestos and another group of 50 with the same age and sex unexposed to asbestos. Malondialdehyde (MDA), total thiol molecule (TTM), total antioxidant capacity (TAC), and DNA damage, were measured in the blood samples of workers and controls. Compared to the control group, the workers showed higher blood levels of DNA damage (P=0.0001) and MDA (P=0.0001). The workers showed lower TTM (P=0.02) as compared with the control group. There was no considerable difference on the level of TAC (P=0.1) between the groups. The workers indicated clinical symptoms such as breathlessness, phlegm, coughing and wheezing. There was a positive correlation between levels of 8-OHdG and MDA of asbestos workers and the smoking status suggesting the negative role of smoking. PMID:27004050

  8. Stem Cells in Skin Regeneration, Wound Healing, and Their Clinical Applications.

    Science.gov (United States)

    Ojeh, Nkemcho; Pastar, Irena; Tomic-Canic, Marjana; Stojadinovic, Olivera

    2015-01-01

    The skin is the largest organ of the body and has an array of functions. Skin compartments, epidermis, and hair follicles house stem cells that are indispensable for skin homeostasis and regeneration. These stem cells also contribute to wound repair, resulting in restoration of tissue integrity and function of damaged tissue. Unsuccessful wound healing processes often lead to non-healing wounds. Chronic wounds are caused by depletion of stem cells and a variety of other cellular and molecular mechanisms, many of which are still poorly understood. Current chronic wound therapies are limited, so the search to develop better therapeutic strategies is ongoing. Adult stem cells are gaining recognition as potential candidates for numerous skin pathologies. In this review, we will discuss epidermal and other stem cells present in the skin, and highlight some of the therapeutic applications of epidermal stem cells and other adult stem cells as tools for cell/scaffold-based therapies for non-healing wounds and other skin disorders. We will also discuss emerging concepts and offer some perspectives on how skin tissue-engineered products can be optimized to provide efficacious therapy in cutaneous repair and regeneration. PMID:26512657

  9. Stem Cells in Skin Regeneration, Wound Healing, and Their Clinical Applications

    Directory of Open Access Journals (Sweden)

    Nkemcho Ojeh

    2015-10-01

    Full Text Available The skin is the largest organ of the body and has an array of functions. Skin compartments, epidermis, and hair follicles house stem cells that are indispensable for skin homeostasis and regeneration. These stem cells also contribute to wound repair, resulting in restoration of tissue integrity and function of damaged tissue. Unsuccessful wound healing processes often lead to non-healing wounds. Chronic wounds are caused by depletion of stem cells and a variety of other cellular and molecular mechanisms, many of which are still poorly understood. Current chronic wound therapies are limited, so the search to develop better therapeutic strategies is ongoing. Adult stem cells are gaining recognition as potential candidates for numerous skin pathologies. In this review, we will discuss epidermal and other stem cells present in the skin, and highlight some of the therapeutic applications of epidermal stem cells and other adult stem cells as tools for cell/scaffold-based therapies for non-healing wounds and other skin disorders. We will also discuss emerging concepts and offer some perspectives on how skin tissue-engineered products can be optimized to provide efficacious therapy in cutaneous repair and regeneration.

  10. Biology and clinical implications of CD133+ liver cancer stem cells

    International Nuclear Information System (INIS)

    Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver, accounting for 80%–90% of all liver cancers. The disease ranks as the fifth most common cancer worldwide and is the third leading cause of all cancer-associated deaths. Although advances in HCC detection and treatment have increased the likelihood of a cure at early stages of the disease, HCC remains largely incurable because of late presentation and tumor recurrence. Only 25% of HCC patients are deemed suitable for curative treatment, with the overall survival at just a few months for inoperable patients. Apart from surgical resection, loco-regional ablation and liver transplantation, current treatment protocols include conventional cytotoxic chemotherapy. But due to the highly resistant nature of the disease, the efficacy of the latter regimen is limited. The recent emergence of the cancer stem cell (CSC) concept lends insight into the explanation of why treatment with chemotherapy often may seem to be initially successful but results in not only a failure to eradicate the tumor but also possibly tumor relapse. Commonly used anti-cancer drugs in HCC work by targeting the rapidly proliferating and differentiated liver cancer cells that constitute the bulk of the tumor. However, a subset of CSCs exists within the tumor, which are more resistant and are able to survive and maintain residence after treatment, thus, growing and self-renewing to generate the development and spread of recurrent tumors in HCC. In the past few years, compelling evidence has emerged in support of the hierarchic CSC model for solid tumors, including HCC. And in particular, CD133 has drawn significant attention as a critical liver CSC marker. Understanding the characteristics and function of CD133+ liver CSCs has also shed light on HCC management and treatment, including the implications for prognosis, prediction and treatment resistance. In this review, a detailed summary of the recent progress in CD

  11. Systemic Delivery of Allogenic Muscle Stem Cells Induces Long-Term Muscle Repair and Clinical Efficacy in Duchenne Muscular Dystrophy Dogs

    Science.gov (United States)

    Rouger, Karl; Larcher, Thibaut; Dubreil, Laurence; Deschamps, Jack-Yves; Le Guiner, Caroline; Jouvion, Gregory; Delorme, Bruno; Lieubeau, Blandine; Carlus, Marine; Fornasari, Benoît; Theret, Marine; Orlando, Priscilla; Ledevin, Mireille; Zuber, Céline; Leroux, Isabelle; Deleau, Stéphane; Guigand, Lydie; Testault, Isabelle; Le Rumeur, Elisabeth; Fiszman, Marc; Chérel, Yan

    2011-01-01

    Duchenne muscular dystrophy (DMD) is a genetic progressive muscle disease resulting from the lack of dystrophin and without effective treatment. Adult stem cell populations have given new impetus to cell-based therapy of neuromuscular diseases. One of them, muscle-derived stem cells, isolated based on delayed adhesion properties, contributes to injured muscle repair. However, these data were collected in dystrophic mice that exhibit a relatively mild tissue phenotype and clinical features of DMD patients. Here, we characterized canine delayed adherent stem cells and investigated the efficacy of their systemic delivery in the clinically relevant DMD animal model to assess potential therapeutic application in humans. Delayed adherent stem cells, named MuStem cells (muscle stem cells), were isolated from healthy dog muscle using a preplating technique. In vitro, MuStem cells displayed a large expansion capacity, an ability to proliferate in suspension, and a multilineage differentiation potential. Phenotypically, they corresponded to early myogenic progenitors and uncommitted cells. When injected in immunosuppressed dystrophic dogs, they contributed to myofiber regeneration, satellite cell replenishment, and dystrophin expression. Importantly, their systemic delivery resulted in long-term dystrophin expression, muscle damage course limitation with an increased regeneration activity and an interstitial expansion restriction, and persisting stabilization of the dog's clinical status. These results demonstrate that MuStem cells could provide an attractive therapeutic avenue for DMD patients. PMID:21924229

  12. Analysis of Femoral Components of Cemented Total Hip Arthroplasty

    Science.gov (United States)

    Singh, Shantanu; Harsha, A. P.

    2015-10-01

    There have been continuous on-going revisions in design of prosthesis in Total Hip Arthroplasty (THA) to improve the endurance of hip replacement. In the present work, Finite Element Analysis was performed on cemented THA with CoCrMo trapezoidal, CoCrMo circular, Ti6Al4V trapezoidal and Ti6Al4V circular stem. It was observed that cross section and material of femoral stem proved to be critical parameters for stress distribution in femoral components, distribution of interfacial stress and micro movements. In the first part of analysis, designs were investigated for micro movements and stress developed, for different stem materials. Later part of the analysis focused on investigations with respect to different stem cross sections. Femoral stem made of Titanium alloy (Ti6Al4V) resulted in larger debonding of stem at cement-stem interface and increased stress within the cement mantle in contrast to chromium alloy (CoCrMo) stem. Thus, CoCrMo proved to be a better choice for cemented THA. Comparison between CoCrMo femoral stem of trapezium and circular cross section showed that trapezoidal stem experiences lesser sliding and debonding at interfaces than circular cross section stem. Also, trapezium cross section generated lower peak stress in femoral stem and cortical femur. In present study, femur head with diameter of 36 mm was considered for the analysis in order to avoid dislocation of the stem. Also, metallic femur head was coupled with cross linked polyethylene liner as it experiences negligible wear compared to conventional polyethylene liner and unlike metallic liner it is non carcinogenic.

  13. Mesenchymal Stem Cells Isolated from Adipose and Other Tissues: Basic Biological Properties and Clinical Applications

    OpenAIRE

    Hakan Orbay; Morikuni Tobita; Hiroshi Mizuno

    2012-01-01

    Mesenchymal stem cells (MSCs) are adult stem cells that were initially isolated from bone marrow. However, subsequent research has shown that other adult tissues also contain MSCs. MSCs originate from mesenchyme, which is embryonic tissue derived from the mesoderm. These cells actively proliferate, giving rise to new cells in some tissues, but remain quiescent in others. MSCs are capable of differentiating into multiple cell types including adipocytes, chondrocytes, osteocytes, and cardiomyoc...

  14. Large animal induced pluripotent stem cells as pre-clinical models for studying human disease

    OpenAIRE

    Jordan R Plews; Gu, Mingxia; Longaker, Michael T.; Joseph C. Wu

    2012-01-01

    Abstract The derivation of human embryonic stem cells and subsequently human induced pluripotent stem cells (iPSCs) has energized regenerative medicine research and enabled seemingly limitless applications. Although small animal models, such as mouse models, have played an important role in the progression of the field, typically, they are poor representations of the human disease phenotype. As an alternative, large animal models should be explored as a potentially better approach for clinica...

  15. Characterization and clinical application of mesenchymal stem cells from equine umbilical cord blood

    OpenAIRE

    Kang, Jun-gu; Park, Sang-Bum; Seo, Min-Soo; Kim, Hyung-Sik; Chae, Joon-Seok; Kang, Kyung-Sun

    2013-01-01

    Tendinitis of the superficial digital flexor tendon (SDFT) is a significant cause of lameness in horses; however, recent studies have shown that stem cells could be useful in veterinary regenerative medicine. Therefore, we isolated and characterized equine umbilical cord blood mesenchymal stem cells (eUCB-MSCs) from equine umbilical cord blood obtained from thoroughbred mares during the foaling period. Horses that had tendinitis of the SDFT were treated with eUCB-MSCs to confirm the therapeut...

  16. Isolation and proliferation of umbilical cord tissue derived mesenchymal stem cells for clinical applications.

    Science.gov (United States)

    Van Pham, Phuc; Truong, Nhat Chau; Le, Phuong Thi-Bich; Tran, Tung Dang-Xuan; Vu, Ngoc Bich; Bui, Khanh Hong-Thien; Phan, Ngoc Kim

    2016-06-01

    Umbilical cord (UC) is a rich source of rapidly proliferating mesenchymal stem cells (MSCs) that are easily cultured on a large-scale. Clinical applications of UC-MSCs include graft-versus-host disease, and diabetes mellitus types 1 and 2. UC-MSCs should be isolated and proliferated according to good manufacturing practice (GMP) with animal component-free medium, quality assurance, and quality control for their use in clinical applications. This study developed a GMP standard protocol for UC-MSC isolation and culture. UC blood and UC were collected from the same donors. Blood vasculature was removed from UC. UC blood was used as a source of activated platelet rich plasma (aPRP). Small fragments (1-2 mm(2)) of UC membrane and Wharton's jelly were cut and cultured in DMEM/F12 medium containing 1 % antibiotic-antimycotic, aPRP (2.5, 5, 7.5 and 10 %) at 37 °C in 5 % CO2. The MSC properties of UC-MSCs at passage 5 such as osteoblast, chondroblast and adipocyte differentiation, and markers including CD13, CD14, CD29, CD34, CD44, CD45, CD73, CD90, CD105, and HLA-DR were confirmed. UC-MSCs also were analyzed for karyotype, expression of tumorigenesis related genes, cell cycle, doubling time as well as in vivo tumor formation in NOD/SCID mice. Control cells consisted of UC-MSCs cultured in DMEM/F12 plus 1 % antibiotic-antimycotic, and 10 % fetal bovine serum (FBS). All UC-MSC (n = 30) samples were successfully cultured in medium containing 7.5 and 10 % aPRP, 92 % of samples grew in 5.0 % aPRP, 86 % of samples in 2.5 % aPRP, and 72 % grew in 10 % FBS. UC-MSCs in these four groups exhibited similar marker profiles. Moreover, the proliferation rates in medium with PRP, especially 7.5 and 10 %, were significantly quicker compared with 2.5 and 5 % aPRP or 10 % FBS. These cells maintained a normal karyotype for 15 sub-cultures, and differentiated into osteoblasts, chondroblasts, and adipocytes. The analysis of pluripotent cell markers showed UC-MSCs maintained

  17. Bone Morphogenetic Proteins in Craniofacial Surgery: Current Techniques, Clinical Experiences, and the Future of Personalized Stem Cell Therapy

    Directory of Open Access Journals (Sweden)

    Kristofer E. Chenard

    2012-01-01

    Full Text Available Critical-size osseous defects cannot heal without surgical intervention and can pose a significant challenge to craniofacial reconstruction. Autologous bone grafting is the gold standard for repair but is limited by a donor site morbidity and a potentially inadequate supply of autologous bone. Alternatives to autologous bone grafting include the use of alloplastic and allogenic materials, mesenchymal stem cells, and bone morphogenetic proteins. Bone morphogenetic proteins (BMPs are essential mediators of bone formation involved in the regulation of differentiation of osteoprogenitor cells into osteoblasts. Here we focus on the use of BMPs in experimental models of craniofacial surgery and clinical applications of BMPs in the reconstruction of the cranial vault, palate, and mandible and suggest a model for the use of BMPs in personalized stem cell therapies.

  18. The Use of a Modular Titanium Baseplate with a Press-Fit Keel Implanted with a Surface Cementing Technique for Primary Total Knee Arthroplasty

    Directory of Open Access Journals (Sweden)

    Christopher E. Pelt

    2014-01-01

    Full Text Available Little data exists regarding outcomes following TKA performed with surface-cementation for the fixation of modular tibial baseplates with press-fit keels. Thus, we retrospectively reviewed the clinical and radiographic outcomes of 439 consecutive primary TKAs performed with surface cemented tibial components. There were 290 female patients and 149 male patients with average age of 62 years (range 30–84. Two tibial components were revised for aseptic loosening (0.5% and four tibial components (0.9% were removed to improve instability (n=2 or malalignment (n=2. Complications included 13 deep infections treated with 2-stage revision (12 and fusion (1. These results support the surface cement technique with a modular grit-blasted titanium surface and cruciform stem during primary TKA.

  19. Biology and clinical implications of CD133{sup +} liver cancer stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Stephanie, E-mail: stefma@hku.hk [Department of Clinical Oncology, State Key Laboratory for Liver Research, LKS Faculty of Medicine, The University of Hong Kong (Hong Kong)

    2013-01-15

    Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver, accounting for 80%–90% of all liver cancers. The disease ranks as the fifth most common cancer worldwide and is the third leading cause of all cancer-associated deaths. Although advances in HCC detection and treatment have increased the likelihood of a cure at early stages of the disease, HCC remains largely incurable because of late presentation and tumor recurrence. Only 25% of HCC patients are deemed suitable for curative treatment, with the overall survival at just a few months for inoperable patients. Apart from surgical resection, loco-regional ablation and liver transplantation, current treatment protocols include conventional cytotoxic chemotherapy. But due to the highly resistant nature of the disease, the efficacy of the latter regimen is limited. The recent emergence of the cancer stem cell (CSC) concept lends insight into the explanation of why treatment with chemotherapy often may seem to be initially successful but results in not only a failure to eradicate the tumor but also possibly tumor relapse. Commonly used anti-cancer drugs in HCC work by targeting the rapidly proliferating and differentiated liver cancer cells that constitute the bulk of the tumor. However, a subset of CSCs exists within the tumor, which are more resistant and are able to survive and maintain residence after treatment, thus, growing and self-renewing to generate the development and spread of recurrent tumors in HCC. In the past few years, compelling evidence has emerged in support of the hierarchic CSC model for solid tumors, including HCC. And in particular, CD133 has drawn significant attention as a critical liver CSC marker. Understanding the characteristics and function of CD133{sup +} liver CSCs has also shed light on HCC management and treatment, including the implications for prognosis, prediction and treatment resistance. In this review, a detailed summary of the recent progress

  20. ULTRA-LIGHTWEIGHT CEMENT

    International Nuclear Information System (INIS)

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Issues, Task 2: Review Russian Ultra-Lightweight Cement Literature, Task 3: Test Ultra-Lightweight Cements, and Task 8: Develop Field ULHS Cement Blending and Mixing Techniques. Results reported this quarter include: preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; summary of pertinent information from Russian ultra-lightweight cement literature review; laboratory tests comparing ULHS slurries to foamed slurries and sodium silicate slurries for two different applications; and initial laboratory studies with ULHS in preparation for a field job

  1. Autologous Stem Cell Injection for Spinal Cord Injury - A Clinical Study from India.

    Directory of Open Access Journals (Sweden)

    Ravikumar R

    2007-01-01

    Full Text Available We studied 100 patients with Spinal Cord injury (SCI after Autologous Stem cell Injection in the Spinal fluid with a Follow up of 6 months post Stem cell injection. There were 69 males and 31 females; age ranging from 8 years to 55 years.? Time after Spinal Injury ranged from 11 years - 3 months (Average: 4.5 years. The Level of Injury ranged from Upper Thoracic (T1-T7 - 34 pts, Lower thoracic (T7-T12 -45 pts, Lumbar -12, Cervical-9 pts. All patients had an MRI Scan, urodynamic study and SSEP (somatosensory Evoked Potential tests before and 3 months after Stem cell Injection.80% of patients had Grade 0 power in the Lower limbs and rest had grade 1-2 power before stem cell injections. 70% of cases had complete lack of Bladder control and 95% had reduced detrusor function.We Extracted CD34 and CD 133 marked Stem cells from 100 ml of Bone marrow Aspirate using Ficoll Gradient method with Cell counting done using flowcytometry.15 ml of the Stem cell concentrate was injected into the Lumbar spinal fluid in aseptic conditions. The CD 34/CD45 counts ranged from 120-400 million cells in the total volume.6 months after Injection, 8 patients had more than 2 grades of Motor power improvement, 3 are able to walk with support. 1 patient with T12/L1 injury was able to walk without support. 12 had sensory tactile and Pain perception improvement and 8 had objective improvement in bladder control and Bladder Muscle contractility. A total of 18 patients had reported or observed improvement in Neurological status. 85% of patients who had motor Improvement had Lesions below T8. MRI, SSEP and Urodynamic Study data are gathered at regular intervals. Conclusion: This study shows that Quantitative and qualitative Improvement in the Neurological status of paralyzed patients after Spinal cord injury is possible after autologous bone marrow Stem cell Injections in select patients. There was no report of Allodynia indicating the safety of the procedure. Further studies to

  2. Potential role of stem cells in severe spinal cord injury: current perspectives and clinical data

    OpenAIRE

    Paspala, Syed Ameer

    2012-01-01

    Syed AB Paspala,1,2 Sandeep K Vishwakarma,1 Tenneti VRK Murthy,2 Thiriveedi N Rao,2 Aleem A Khan11PAN Research Foundation, CARE, 2The Institute of Medical Sciences, Hyderabad, IndiaAbstract: Stem cell transplantation for spinal cord injury (SCI) along with new pharmacotherapy research offers the potential to restore function and ease the associated social and economic burden in the years ahead. Various sources of stem cells have been used in the treatment of SCI, but the most convincing resul...

  3. Towards a clinically relevant lentiviral transduction protocol for primary human CD34 hematopoietic stem/progenitor cells.

    Directory of Open Access Journals (Sweden)

    Michelle Millington

    Full Text Available BACKGROUND: Hematopoietic stem cells (HSC, in particular mobilized peripheral blood stem cells, represent an attractive target for cell and gene therapy. Efficient gene delivery into these target cells without compromising self-renewal and multi-potency is crucial for the success of gene therapy. We investigated factors involved in the ex vivo transduction of CD34(+ HSCs in order to develop a clinically relevant transduction protocol for gene delivery. Specifically sought was a protocol that allows for efficient transduction with minimal ex vivo manipulation without serum or other reagents of animal origin. METHODOLOGY/PRINCIPAL FINDINGS: Using commercially available G-CSF mobilized peripheral blood (PB CD34(+ cells as the most clinically relevant target, we systematically examined factors including the use of serum, cytokine combinations, pre-stimulation time, multiplicity of infection (MOI, transduction duration and the use of spinoculation and/or retronectin. A self-inactivating lentiviral vector (SIN-LV carrying enhanced green fluorescent protein (GFP was used as the gene delivery vehicle. HSCs were monitored for transduction efficiency, surface marker expression and cellular function. We were able to demonstrate that efficient gene transduction can be achieved with minimal ex vivo manipulation while maintaining the cellular function of transduced HSCs without serum or other reagents of animal origin. CONCLUSIONS/SIGNIFICANCE: This study helps to better define factors relevant towards developing a standard clinical protocol for the delivery of SIN-LV into CD34(+ cells.

  4. Derivation of Xeno-Free and GMP-Grade Human Embryonic Stem Cells – Platforms for Future Clinical Applications

    OpenAIRE

    Tannenbaum, Shelly E.; Tako Turetsky, Tikva; Singer, Orna; Aizenman, Einat; Kirshberg, Sophie; Ilouz, Nili; Gil, Yaniv; Berman-Zaken, Yael; Perlman, Temima Schnitzer; Geva, Nitshia; Levy, Ora; Arbell, Daniel; Simon, Alex; Ben-Meir, Assaf; Shufaro, Yoel

    2012-01-01

    Clinically compliant human embryonic stem cells (hESCs) should be developed in adherence to ethical standards, without risk of contamination by adventitious agents. Here we developed for the first time animal-component free and good manufacturing practice (GMP)-compliant hESCs. After vendor and raw material qualification, we derived xeno-free, GMP-grade feeders from umbilical cord tissue, and utilized them within a novel, xeno-free hESC culture system. We derived and characterized three hESC ...

  5. [Cement augmentation of pedicle screws : Pros and cons].

    Science.gov (United States)

    Schnake, K J; Blattert, T R; Liljenqvist, U

    2016-09-01

    Cement augmentation of pedicle screws biomechanically increases screw purchase in the bone. However, clinical complications may occur. The pros and cons of the technique are discussed from different clinical perspectives. PMID:27514827

  6. Stem cell biobanks.

    Science.gov (United States)

    Bardelli, Silvana

    2010-04-01

    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

  7. Mesenchymal and induced pluripotent stem cells: general insights and clinical perspectives

    Directory of Open Access Journals (Sweden)

    Zomer HD

    2015-09-01

    Full Text Available Helena D Zomer,1 Atanásio S Vidane,1 Natalia N Gonçalves,1 Carlos E Ambrósio2 1Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil; 2Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering, University of São Paulo, Pirassununga, SP, Brazil Abstract: Mesenchymal stem cells have awakened a great deal of interest in regenerative medicine due to their plasticity, and immunomodulatory and anti-inflammatory properties. They are high-yield and can be acquired through noninvasive methods from adult tissues. Moreover, they are nontumorigenic and are the most widely studied. On the other hand, induced pluripotent stem (iPS cells can be derived directly from adult cells through gene reprogramming. The new iPS technology avoids the embryo destruction or manipulation to generate pluripotent cells, therefore, are exempt from ethical implication surrounding embryonic stem cell use. The pre-differentiation of iPS cells ensures the safety of future approaches. Both mesenchymal stem cells and iPS cells can be used for autologous cell transplantations without the risk of immune rejection and represent a great opportunity for future alternative therapies. In this review we discussed the therapeutic perspectives using mesenchymal and iPS cells. Keywords: cell transplantation, cell therapy, iPS, MSC

  8. Chemical and physical properties of bone cement for vertebroplasty

    Directory of Open Access Journals (Sweden)

    Po-Liang Lai

    2013-08-01

    Full Text Available Vertebral compression fracture is the most common complication of osteoporosis. It may result in persistent severe pain and limited mobility, and significantly impacts the quality of life. Vertebroplasty involves a percutaneous injection of bone cement into the collapsed vertebrae by fluorescent guide. The most commonly used bone cement in percutaneous vertebroplasty is based on the polymerization of methylmethacrylate monomers to polymethylmethacrylate (PMMA polymers. However, information on the properties of bone cement is mostly published in the biomaterial sciences literature, a source with which the clinical community is generally unfamiliar. This review focuses on the chemistry of bone cement polymerization and the physical properties of PMMA. The effects of altering the portions and contents of monomer liquid and polymer powders on the setting time, polymerization temperature, and compressive strength of the cement are also discussed. This information will allow spine surgeons to manipulate bone cement characteristics for specific clinical applications and improve safety.

  9. ULTRA-LIGHTWEIGHT CEMENT

    International Nuclear Information System (INIS)

    The objective of this project is to develop an improved ultra-lightweigh cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems, Task 2: Review Russian Ultra-Lightweight Cement Literature, and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary surface pipe and intermediate casing cementing conditions historically encountered in the US and establishment of average design conditions for ULHS cements. Russian literature concerning development and use of ultra-lightweight cements employing either nitrogen or ULHS was reviewed, and a summary is presented. Quality control testing of materials used to formulate ULHS cements in the laboratory was conducted to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS. This protocol is presented and discussed. finally, results of initial testing of ULHS cements is presented along with analysis to establish cement performance design criteria to be used during the remainder of the project

  10. Clinical-Grade Manufacturing of Therapeutic Human Mesenchymal Stem/Stromal Cells in Microcarrier-Based Culture Systems.

    Science.gov (United States)

    Fernandes-Platzgummer, Ana; Carmelo, Joana G; da Silva, Cláudia Lobato; Cabral, Joaquim M S

    2016-01-01

    The therapeutic potential of mesenchymal stem/stromal cells (MSC) has triggered the need for high cell doses in a vast number of clinical applications. This demand requires the development of good manufacturing practices (GMP)-compliant ex vivo expansion protocols that should be effective to deliver a robust and reproducible supply of clinical-grade cells in a safe and cost-effective manner. Controlled stirred-tank bioreactor systems under xenogeneic (xeno)-free culture conditions offer ideal settings to develop and optimize cell manufacturing to meet the standards and needs of human MSC for cellular therapies. Herein we describe two microcarrier-based stirred culture systems using spinner flasks and controlled stirred-tank bioreactors under xeno-free conditions for the efficient ex vivo expansion of human bone marrow and adipose tissue-derived MSC. PMID:27236684

  11. Symptomatic knee osteoarthritis treatment using autologous adipose derived stem cells and platelet-rich plasma: a clinical study

    Directory of Open Access Journals (Sweden)

    Phuc Van Pham

    2014-01-01

    Full Text Available Osteoarthritis is one of the most common diseases, and it affects 12% of the population around the world. Although the disease is chronic, it significantly reduces the patient's quality of life. At present, stem cell therapy is considered to be an efficient approach for treating this condition. Mesenchymal stem cells (MSCs show the most potential for stem cell therapy of osteoarthritis. In fact, MSCs can differentiate into certain mesodermal tissues such as cartilage and bone. Therefore, in the present study, we applied adipose tissue-derived MSCs to osteoarthritis treatment. This study aimed to evaluate the clinical efficiency of autologous adipose tissue-derived MSC transplantation in patients with confirmed osteoarthritis at grade II and III. Adipose tissue was isolated from the belly, and used for extraction of the stromal vascular fraction (SVF. The SVF was mixed with activated platelet- rich plasma before injection. The clinical efficiencies were evaluated by the pain score (VAS, Lysholm score, and MRI findings. We performed the procedure in 21 cases from 2012 to 2013. All 21 patients showed improved joint function after 8.5 months. The pain score decreased from 7.6+/-0.5 before injection to 3.5+/-0.7 at 3 months and 1.5+/-0.5 at 6 months after injection. The Lysholm score increased from 61+/-11 before injection to 82+/-8.1 after injection. Significant improvements were noted in MRI findings, with increased thickness of the cartilage layer. Moreover, there were no side-effects or complications related to microorganism infection, graft rejection, or tumorigenesis. These results provide a new opportunity for osteoarthritis treatment. Level of evidence: IV. [Biomed Res Ther 2014; 1(1.000: 02-08

  12. A Biomimetic Hip Joint Simulator and its Application in in vitro Study of the Integrity of Replacement Cemented Hip

    Institute of Scientific and Technical Information of China (English)

    Liu Chao-zong; S.M.Green; N.D.Watkins; A.W.McCaskie

    2005-01-01

    A biomimetic hip joint simulator that can be used to evaluate the outcome of the cemented total hip replacement has been designed, manufactured and evaluated. The simulator produces motion in the extension/flexion plane, with a socket to rotate internal/externally. At the same time a dynamic loading cycle is applied. A validation test was performed on a cemented femoral stem within a novel composite femur. The bone quality has a strong effect on the stem migration and on the integrity of the interfaces. The migration of the stem is a combination of 3-D translation and rotation of the stem. Under the same loading conditions, weak bone allows more stem migration than strong bone. There is a great decrease in the strength of the stem-cement interface after the dynamic test, and the weak bone composite exhibited a greater reduction in interfacial strength than the strong bone composite. The decrease of the interfacial strength indicates that the primary bonding between the stem and the cement mantle had deteriorated and the integrity of stem-cement interface was damaged.The study demonstrates the value of using a hip joint simulator to investigate stem migration and interface integrity within the cemented hip replacement, suggesting that method can be used for in vitro evaluation of the biomaterials used in the cemented hip replacements.

  13. cGMP-Manufactured Human Induced Pluripotent Stem Cells Are Available for Pre-clinical and Clinical Applications

    Directory of Open Access Journals (Sweden)

    Behnam Ahmadian Baghbaderani

    2015-10-01

    Full Text Available The discovery of induced pluripotent stem cells (iPSCs and the concurrent development of protocols for their cell-type-specific differentiation have revolutionized our approach to cell therapy. It has now become critical to address the challenges related to the generation of iPSCs under current good manufacturing practice (cGMP compliant conditions, including tissue sourcing, manufacturing, testing, and storage. Furthermore, regarding the technical challenges, it is very important to keep the costs of manufacturing and testing reasonable and solve logistic hurdles that permit the global distribution of these products. Here we describe our efforts to develop a process for the manufacturing of iPSC master cell banks (MCBs under cGMPs and announce the availability of such banks.

  14. The Molecular Karyotype of 25 Clinical-Grade Human Embryonic Stem Cell Lines

    OpenAIRE

    Canham, Maurice A; Amy Van Deusen; Daniel R Brison; De Sousa, Paul A.; Janet Downie; Liani Devito; Hewitt, Zoe A; Dusko Ilic; Kimber, Susan J.; Moore, Harry D; Helen Murray; Tilo Kunath

    2015-01-01

    The application of human embryonic stem cell (hESC) derivatives to regenerative medicine is now becoming a reality. Although the vast majority of hESC lines have been derived for research purposes only, about 50 lines have been established under Good Manufacturing Practice (GMP) conditions. Cell types differentiated from these designated lines may be used as a cell therapy to treat macular degeneration, Parkinson's, Huntington's, diabetes, osteoarthritis and other degenerative conditions. It ...

  15. Melanoma: Stem cells, sun exposure and hallmarks for carcinogenesis, molecular concepts and future clinical implications

    Directory of Open Access Journals (Sweden)

    Kyrgidis Athanassios

    2010-01-01

    Full Text Available Background :The classification and prognostic assessment of melanoma is currently based on morphologic and histopathologic biomarkers. Availability of an increasing number of molecular biomarkers provides the potential for redefining diagnostic and prognostic categories and utilizing pharmacogenomics for the treatment of patients. The aim of the present review is to provide a basis that will allow the construction-or reconstruction-of future melanoma research. Methods: We critically review the common medical databases (PubMed, EMBASE, Scopus and Cochrane CENTRAL for studies reporting on molecular biomarkers for melanoma. Results are discussed along the hallmarks proposed for malignant transformation by Hanahan and Weinberg. We further discuss the genetic basis of melanoma with regard to the possible stem cell origin of melanoma cells and the role of sunlight in melanoma carcinogenesis. Results: Melanocyte precursors undergo several genome changes -UV-induced or not- which could be either mutations or epigenetic. These changes provide stem cells with abilities to self-invoke growth signals, to suppress anti-growth signals, to avoid apoptosis, to replicate without limit, to invade, proliferate and sustain angiogenesis. Melanocyte stem cells are able to progressively collect these changes in their genome. These new potential functions, drive melanocyte precursors to the epidermis were they proliferate and might cause benign nevi. In the epidermis, they are still capable of acquiring new traits via changes to their genome. With time, such changes could add up to transform a melanocyte precursor to a malignant melanoma stem cell. Conclusions : Melanoma cannot be considered a "black box" for researchers anymore. Current trends in the diagnosis and prognosis of melanoma are to individualize treatment based on molecular biomarkers. Pharmacogenomics constitute a promising field with regard to melanoma patients′ treatment. Finally, development of novel

  16. Breast cancer stem-like cells: clinical implications and therapeutic strategies

    Science.gov (United States)

    TUDORAN, OANA MIHAELA; BALACESCU, OVIDIU; BERINDAN-NEAGOE, IOANA

    2016-01-01

    Breast cancer is the most frequently diagnosed cancer in women, being also the leading cause of cancer death among female population, including in Romania. Resistance to therapy represents a major problem for cancer treatment. Current cancer treatments are both expensive and induce serious side effects; therefore ineffective therapies are both traumatic and pricy. Characterizing predictive markers that can identify high-risk patients could contribute to dedicated/personalized therapy to improve the life quality and expectancy of cancer patients. Moreover, there are some markers that govern specific tumor molecular features that can be targeted with specific therapies for those patients who are most likely to benefit. The identification of stem cells in both normal and malignant breast tissue have lead to the hypothesis that breast tumors arise from breast cancer stem-like cells (CSCs), and that these cells influence tumor’s response to therapy. CSCs have similar self-renewal properties to normal stem cells, however the balance between the signaling pathways is altered towards tumor formation In this review, we discuss the molecular aspects of breast CSCs and the controversies regarding their use in the diagnosis and treatment decision of breast cancer patients.

  17. Essential Gene Pathways for Glioblastoma Stem Cells: Clinical Implications for Prevention of Tumor Recurrence

    International Nuclear Information System (INIS)

    Glioblastoma (World Health Organization/WHO grade IV) is the most common and most aggressive adult glial tumor. Patients with glioblastoma, despite being treated with gross total resection and post-operative radiation/chemotherapy, will almost always develop tumor recurrence. Glioblastoma stem cells (GSC), a minor subpopulation within the tumor mass, have been recently characterized as tumor-initiating cells and hypothesized to be responsible for post-treatment recurrence because of their enhanced radio-/chemo-resistant phenotype and ability to reconstitute tumors in mouse brains. Genome-wide expression profile analysis uncovered molecular properties of GSC distinct from their differentiated, proliferative progeny that comprise the majority of the tumor mass. In contrast to the hyperproliferative and hyperangiogenic phenotype of glioblastoma tumors, GSC possess neuroectodermal properties and express genes associated with neural stem cells, radial glial cells, and neural crest cells, as well as portray a migratory, quiescent, and undifferentiated phenotype. Thus, cell cycle-targeted radio-chemotherapy, which aims to kill fast-growing tumor cells, may not completely eliminate glioblastoma tumors. To prevent tumor recurrence, a strategy targeting essential gene pathways of GSC must be identified and incorporated into the standard treatment regimen. Identifying intrinsic and extrinsic cues by which GSC maintain stemness properties and sustain both tumorigenesis and anti-apoptotic features may provide new insights into potentially curative strategies for treating brain cancers

  18. Reinforcement of bone cement around prostheses by pre-coated wire coil: a preliminary study.

    Science.gov (United States)

    Kim, J K; Park, J B

    1994-01-01

    The longevity of the cemented total hip joint replacement depends on the integrity of the cement fixation with respect to the interfaces of the metal stem and bone, and stress/strain transmission and its distribution. A simple coil made of stainless steel wires was placed around a tapered stem in a simulated cement mantle to counteract the radial- and hoop-stress and static push-out mechanical tests were performed. The results show statistically significant increases in ultimate strain (+17.62%), ultimate load (+110.34%), stiffness (+117.63%), and fracture toughness (+153.63%) exhibited by the wire reinforcement over the control. Precoating with thin layer of polymethylmethacrylate may also enhance the mechanical properties of the reinforced cement mantle. This simple device may contribute to the longevity of the cement mantle by virtue of the enhanced mechanical properties, which in turn will be able to absorb more energy transmitted through the metal stem. PMID:8000291

  19. Iron labeling and pre-clinical MRI visualization of therapeutic human neural stem cells in a murine glioma model.

    Directory of Open Access Journals (Sweden)

    Mya S Thu

    Full Text Available BACKGROUND: Treatment strategies for the highly invasive brain tumor, glioblastoma multiforme, require that cells which have invaded into the surrounding brain be specifically targeted. The inherent tumor-tropism of neural stem cells (NSCs to primary and invasive tumor foci can be exploited to deliver therapeutics to invasive brain tumor cells in humans. Use of the strategy of converting prodrug to drug via therapeutic transgenes delivered by immortalized therapeutic NSC lines have shown efficacy in animal models. Thus therapeutic NSCs are being proposed for use in human brain tumor clinical trials. In the context of NSC-based therapies, MRI can be used both to non-invasively follow dynamic spatio-temporal patterns of the NSC tumor targeting allowing for the optimization of treatment strategies and to assess efficacy of the therapy. Iron-labeling of cells allows their presence to be visualized and tracked by MRI. Thus we aimed to iron-label therapeutic NSCs without affecting their cellular physiology using a method likely to gain United States Federal Drug Administration (FDA approval. METHODOLOGY: For human use, the characteristics of therapeutic Neural Stem Cells must be clearly defined with any pertubation to the cell including iron labeling requiring reanalysis of cellular physiology. Here, we studied the effect of iron-loading of the therapeutic NSCs, with ferumoxide-protamine sulfate complex (FE-Pro on viability, proliferation, migratory properties and transgene expression, when compared to non-labeled cells. FE-Pro labeled NSCs were imaged by MRI at tumor sites, after intracranial administration into the hemisphere contralateral to the tumor, in an orthotopic human glioma xenograft mouse model. CONCLUSION: FE-Pro labeled NSCs retain their proliferative status, tumor tropism, and maintain stem cell character, while allowing in vivo cellular MRI tracking at 7 Tesla, to monitor their real-time migration and distribution at brain tumor sites

  20. Injectable citrate-modified Portland cement for use in vertebroplasty.

    Science.gov (United States)

    Wynn-Jones, Gareth; Shelton, Richard M; Hofmann, Michael P

    2014-11-01

    The injectability of Portland cement (PC) with several citrate additives was investigated for use in clinical applications such as vertebroplasty (stabilization of a fractured vertebra with bone cement) using a syringe. A 2-wt % addition of sodium or potassium citrate with PC significantly improved cement injectability, decreased cement setting times from over 2 h to below 25 min, while increasing the compressive strength to a maximum of 125 MPa. Zeta-potential measurements indicated that the citrate anion was binding to one or more of the positively charged species causing charged repulsion between cement particles which dispersed aggregates and caused the liquefying effect of the anion. Analysis of the hydrating phases of PC indicated that the early strength producing PC phase (ettringite) developed within the first 2 h of setting following addition of the citrate anion, while this did not occur in the control cement (PC only). Within 24 h ettringite developed in PC as well as calcium-silicate-hydrate (C-S-H), the major setting phase of PC, whereas cements containing citrate did not develop this phase. The evidence suggested that in the presence of citrate the cements limited water supply appeared to be utilized for ettringite formation, producing the early strength of the citrate cements. The present study has demonstrated that it is possible to modify PC with citrate to both improve the injectability and crucially reduce the setting times of PC while improving the strength of the cement. PMID:24711245

  1. Derivation of the clinical grade human embryonic stem cell line RCe017-A (RC-13

    Directory of Open Access Journals (Sweden)

    P.A. De Sousa

    2016-05-01

    Full Text Available The human embryonic stem cell line RCe017-A (RC-13 was derived under quality assured compliance with UK regulation, European Union Directives and International guidance for tissue procurement, processing and storage according to Good Manufacturing Practice (GMP standards. The cell line was derived from a frozen and thawed blastocyst stage embryo voluntarily donated as unsuitable or surplus to fertility requirements following informed consent. RCe017-A (RC-13 shows normal pluripotency marker expression and differentiation to the three germ layers in vitro. It has a mixed 47XY, +12/48XY, +1, +12 male karyotype and microsatellite PCR identity, HLA and blood group typing data are available.

  2. Derivation of the clinical grade human embryonic stem cell line RCe017-A (RC-13).

    Science.gov (United States)

    De Sousa, P A; Tye, B J; Bruce, K; Dand, P; Russell, G; Collins, D M; Greenshields, A; McDonald, K; Bradburn, H; Laurie, A; Downie, J M; Bateman, M; Courtney, A

    2016-05-01

    The human embryonic stem cell line RCe017-A (RC-13) was derived under quality assured compliance with UK regulation, European Union Directives and International guidance for tissue procurement, processing and storage according to Good Manufacturing Practice (GMP) standards. The cell line was derived from a frozen and thawed blastocyst stage embryo voluntarily donated as unsuitable or surplus to fertility requirements following informed consent. RCe017-A (RC-13) shows normal pluripotency marker expression and differentiation to the three germ layers in vitro. It has a mixed 47XY, +12/48XY, +1, +12 male karyotype and microsatellite PCR identity, HLA and blood group typing data are available. PMID:27346201

  3. Derivation of the clinical grade human embryonic stem cell line RCe016-A (RC-12).

    Science.gov (United States)

    De Sousa, P A; Tye, B J; Bruce, K; Dand, P; Russell, G; Collins, D M; Greenshields, A; McDonald, K; Bradburn, H; Laurie, A; Downie, J M; Bateman, M; Courtney, A

    2016-05-01

    The human embryonic stem cell line RCe016-A (RC-12) was derived under quality assured compliance with UK regulations, EU Directives and International guidance for tissue procurement, processing and storage according to good manufacturing practice (GMP) standards. The cell line was derived from a cryopreserved blastocyst stage embryo voluntarily donated as surplus to fertility requirements following informed consent. RCe016-A (RC-12) shows normal pluripotency marker expression and differentiation to three germ layers in vitro. Karyology revealed a mixed male karyotype at early passage (P15), which resolved as normal 46XY by passage 33. Microsatellite PCR identity, HLA and blood group typing data is available. PMID:27346204

  4. Derivation of the clinical grade human embryonic stem cell line RCe019-A (RC-15).

    Science.gov (United States)

    De Sousa, P A; Tye, B J; Bruce, K; Dand, P; Russell, G; Collins, D M; Greenshields, A; McDonald, K; Bradburn, H; Laurie, A; Downie, J M; Bateman, M; Courtney, A

    2016-05-01

    The human embryonic stem cell line RCe019-A (RC-15) was derived under quality assured compliance with UK regulation, European Union Directives and International guidance for tissue procurement, processing and storage according to Good Manufacturing Practice (GMP) standards. The cell line was derived from a cleavage stage embryo voluntarily donated as unsuitable or surplus to fertility requirements following informed consent. RCe019-A (RC-15) shows normal pluripotency marker expression and differentiation to the three germ layers in vitro. It has a mixed 46XX/47XX, +8 female karyotype and microsatellite PCR identity, HLA and blood group typing data is available. PMID:27346200

  5. Derivation of the clinical grade human embryonic stem cell line RCe016-A (RC-12

    Directory of Open Access Journals (Sweden)

    P.A. De Sousa

    2016-05-01

    Full Text Available The human embryonic stem cell line RCe016-A (RC-12 was derived under quality assured compliance with UK regulations, EU Directives and International guidance for tissue procurement, processing and storage according to good manufacturing practice (GMP standards. The cell line was derived from a cryopreserved blastocyst stage embryo voluntarily donated as surplus to fertility requirements following informed consent. RCe016-A (RC-12 shows normal pluripotency marker expression and differentiation to three germ layers in vitro. Karyology revealed a mixed male karyotype at early passage (P15, which resolved as normal 46XY by passage 33. Microsatellite PCR identity, HLA and blood group typing data is available.

  6. Derivation of the clinical grade human embryonic stem cell line RCe019-A (RC-15

    Directory of Open Access Journals (Sweden)

    P.A. De Sousa

    2016-05-01

    Full Text Available The human embryonic stem cell line RCe019-A (RC-15 was derived under quality assured compliance with UK regulation, European Union Directives and International guidance for tissue procurement, processing and storage according to Good Manufacturing Practice (GMP standards. The cell line was derived from a cleavage stage embryo voluntarily donated as unsuitable or surplus to fertility requirements following informed consent. RCe019-A (RC-15 shows normal pluripotency marker expression and differentiation to the three germ layers in vitro. It has a mixed 46XX/47XX, +8 female karyotype and microsatellite PCR identity, HLA and blood group typing data is available.

  7. Challenges of stem cell-based pulp and dentin regeneration: a clinical perspective

    OpenAIRE

    Huang, George T.-J.; Al-Habib, Mey; Gauthier, Philippe

    2013-01-01

    There are two types of approaches to regenerate tissues: cell-based and cell-free. The former approach is to introduce exogenous cells into the host to regenerate tissues, and the latter is to use materials other than cells in an attempt to regenerate tissues. There has been a significant advancement in stem cell-based pulp and dentin regeneration research in the past few years. Studies in small and large animals have demonstrated that pulp/dentin-like tissues can be regenerated partially or ...

  8. Mesenchymal and induced pluripotent stem cells: general insights and clinical perspectives

    OpenAIRE

    Zomer HD; Vidane AS; Gonçalves NN; Ambrósio CE

    2015-01-01

    Helena D Zomer,1 Atanásio S Vidane,1 Natalia N Gonçalves,1 Carlos E Ambrósio2 1Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil; 2Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering, University of São Paulo, Pirassununga, SP, Brazil Abstract: Mesenchymal stem cells have awakened a great deal of interest in regenerative medicine due to their plastici...

  9. Clinical use of statins in hematopoietic stem cell transplantation: Old drugs and new horizons.

    Science.gov (United States)

    Mohammadi, Mehdi; Vaezi, Mohammad; Mirrahimi, Bahador; Hadjibabaie, Molouk

    2016-01-01

    Hydroxymethylglutaryl Co-enzyme A reductase inhibitors, also known as statins, are a class of anti-hyperlipidemic agents. These drugs have been employed vastly to reduce the morbidity and mortality of cardiovascular disorders. Soon after their introduction, benefits other than their primary actions were discovered. Along with these pleiotropic properties, a series of mainly favorable effects has been proposed in patients intended to undergo hematopoietic stem cell transplantation. These actions address some complications encountered by this special population such as graft-versus-host disease, efficacy of chemotherapy, infections, etc. This review presents the current evidence surrounding these issues. PMID:27047650

  10. Injectable bioactive calcium-magnesium phosphate cement for bone regeneration

    International Nuclear Information System (INIS)

    Novel injectable and degradable calcium-magnesium phosphate cement (CMPC) with rapid-setting characteristic was developed by the introduction of magnesium phosphate cement (MPC) into calcium phosphate cement (CPC). The calcium-magnesium phosphate cement prepared under the optimum P/L ratio exhibited good injectability and desired workability. It could set within 10 min at 37 0C in 100% relative humidity and the compressive strength could reach 47 MPa after setting for 48 h, indicating that the prepared cement has relatively high initial mechanical strength. The results of in vitro degradation experiments demonstrated the good degradability of the injectable CMPC, and its degradation rate occurred significantly faster than that of pure CPC in simulated body fluid (SBF) solution. It can be concluded that the novel injectable calcium-magnesium phosphate cement is highly promising for a wide variety of clinical applications, especially for the development of minimally invasive techniques.

  11. Clinical trial perspective for adult and juvenile Huntington's disease using genetically-engineered mesenchymal stem cells.

    Science.gov (United States)

    Deng, Peter; Torrest, Audrey; Pollock, Kari; Dahlenburg, Heather; Annett, Geralyn; Nolta, Jan A; Fink, Kyle D

    2016-05-01

    Progress to date from our group and others indicate that using genetically-engineered mesenchymal stem cells (MSC) to secrete brain-derived neurotrophic factor (BDNF) supports our plan to submit an Investigational New Drug application to the Food and Drug Administration for the future planned Phase 1 safety and tolerability trial of MSC/BDNF in patients with Huntington's disease (HD). There are also potential applications of this approach beyond HD. Our biological delivery system for BDNF sets the precedent for adult stem cell therapy in the brain and could potentially be modified for other neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), spinocerebellar ataxia (SCA), Alzheimer's disease, and some forms of Parkinson's disease. The MSC/BDNF product could also be considered for studies of regeneration in traumatic brain injury, spinal cord and peripheral nerve injury. This work also provides a platform for our future gene editing studies, since we will again use MSCs to deliver the needed molecules into the central nervous system. PMID:27335539

  12. Clinical trial perspective for adult and juvenile Huntington's disease using genetically-engineered mesenchymal stem cells

    Science.gov (United States)

    Deng, Peter; Torrest, Audrey; Pollock, Kari; Dahlenburg, Heather; Annett, Geralyn; Nolta, Jan A.; Fink, Kyle D.

    2016-01-01

    Progress to date from our group and others indicate that using genetically-engineered mesenchymal stem cells (MSC) to secrete brain-derived neurotrophic factor (BDNF) supports our plan to submit an Investigational New Drug application to the Food and Drug Administration for the future planned Phase 1 safety and tolerability trial of MSC/BDNF in patients with Huntington's disease (HD). There are also potential applications of this approach beyond HD. Our biological delivery system for BDNF sets the precedent for adult stem cell therapy in the brain and could potentially be modified for other neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), spinocerebellar ataxia (SCA), Alzheimer's disease, and some forms of Parkinson's disease. The MSC/BDNF product could also be considered for studies of regeneration in traumatic brain injury, spinal cord and peripheral nerve injury. This work also provides a platform for our future gene editing studies, since we will again use MSCs to deliver the needed molecules into the central nervous system. PMID:27335539

  13. Advanced cementation concepts

    International Nuclear Information System (INIS)

    The purpose of this programme of work was to investigate whether improvements could be made to existing formulations for cement suitable for the immobilization of intermediate level radioactive waste. Two additives were selected, microsilica and limestone flour. Improvements to the cement were only slight. (author)

  14. A xenogeneic-free protocol for isolation and expansion of human adipose stem cells for clinical uses.

    Directory of Open Access Journals (Sweden)

    Carmen Escobedo-Lucea

    Full Text Available Human adipose stem cells (HASCS play a crucial role in the fields of regenerative medicine and tissue engineering for different reasons: the abundance of adipose tissue, their easy harvesting, the ability to multipotent differentiation and the fact that they do not trigger allogeneic blood response or secrete cytokines that act as immunosuppressants. The vast majority of protocols use animal origin reagents, with the underlying risk of transmitting infections by non-human pathogens. We have designed a protocol to isolate and maintain the properties of hASCs avoiding xenogeneic reagents. These changes not only preserve hASCs morphology, but also increase cell proliferation and maintain their stem cell marker profile. On the other hand, human serum albumin (HSA, Tryple® and human Serum (HS, do not affect hASCs multipotent differentiation ability. The amendments introduced do not trigger modifications in the transcriptional profile of hASCs, alterations in key biochemical pathways or malignization. Thus, we have proven that it is possible to isolate and maintain hASCs avoiding animal reagents and, at the same time, preserving crucial culture parameters during long term culture. Thereby we have revealed a novel and effective tool for the improvement of clinical, cell-based therapies.

  15. Clinical-scale cultures of cord blood CD34(+) cells to amplify committed progenitors and maintain stem cell activity.

    Science.gov (United States)

    Ivanovic, Zoran; Duchez, Pascale; Chevaleyre, Jean; Vlaski, Marija; Lafarge, Xavier; Dazey, Bernard; Robert-Richard, Elodie; Mazurier, Frédéric; Boiron, Jean-Michel

    2011-01-01

    We developed a clinical-scale cord blood (CB) cell ex vivo procedure to enable an extensive expansion of committed progenitors--colony-forming cells (CFCs) without impairing very primitive hematopoietic stem cells (HSCs). CD34(++) cells, selected from previously cryopreserved and thawed CB units, were cultured in two steps (diluted 1:4 after 6 days) in the presence of stem cell factor (SCF), fms-related tyrosine kinase 3 ligand (Flt-3L), megakaryocyte growth and development factor (MGDF) (100 ng/ml each), granulocyte-colony stimulating factor (G-CSF) (10 ng/ml) in HP01 serum-free medium. HSC activity was evaluated in a serial transplantation assay, by detection of human cells (CD45, CD33, CD19 and CFC of human origin) in bone marrow (BM) of primary and secondary recipient NOD/SCID mice 6-8 weeks after transplantation. A wide amplification of total cells (∼350-fold), CD34(+) cells (∼100-fold), and CFC (∼130-fold) without impairing the HSC activity was obtained. The activity of a particular HSC subpopulation (SRC(CFC)) was even enhanced.Thus, an extensive ex vivo expansion of CFCs is feasible without impairing the activity of HSCs. This result was enabled by associating antioxidant power of medium with an appropriate cytokine cocktail (i.e., mimicking physiologic effects of a weak oxygenation in hematopoietic environment). PMID:21294956

  16. Preclinical Biosafety Evaluation of Genetically Modified Human Adipose Tissue-Derived Mesenchymal Stem Cells for Clinical Applications to Brainstem Glioma.

    Science.gov (United States)

    Choi, Seung Ah; Yun, Jun-Won; Joo, Kyeung Min; Lee, Ji Yeoun; Kwak, Pil Ae; Lee, Young Eun; You, Ji-Ran; Kwon, Euna; Kim, Woo Ho; Wang, Kyu-Chang; Phi, Ji Hoon; Kang, Byeong-Cheol; Kim, Seung-Ki

    2016-06-15

    Stem-cell based gene therapy is a promising novel therapeutic approach for inoperable invasive tumors, including brainstem glioma. Previously, we demonstrated the therapeutic potential of human adipose tissue-derived mesenchymal stem cells (hAT-MSC) genetically engineered to express a secreted form of tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) against brainstem glioma. However, safety concerns should be comprehensively investigated before clinical applications of hAT-MSC.sTRAIL. At first, we injected stereotactically low (1.2 × 10(5) cells/18 μL), medium (2.4 × 10(5)/18 μL), or high dose (3.6 × 10(5)/18 μL) of hAT-MSC.sTRAIL into the brainstems of immunodeficient mice reflecting the plan of the future clinical trial. Local toxicity, systemic toxicity, secondary tumor formation, and biodistribution of hAT-MSC.sTRAIL were investigated. Next, presence of hAT-MSC.sTRAIL was confirmed in the brain and major organs at 4, 9, and 14 weeks in brainstem glioma-bearing mice. In the 15-week subchronic toxicity test, no serious adverse events in terms of body weight, food consumption, clinical symptom, urinalysis, hematology, clinical chemistry, organ weight, and histopathology were observed. In the 26-week tumorigenicity test, hAT-MSC.sTRAIL made no detectable tumors, whereas positive control U-87 MG cells made huge tumors in the brainstem. No remaining hAT-MSC.sTRAIL was observed in any organs examined, including the brainstem at 15 or 26 weeks. In brainstem glioma-bearing mice, injected hAT-MSC.sTRAIL was observed, but gradually decreased over time in the brain. The mRNA of human specific GAPDH and TRAIL was not detected in all major organs. These results indicate that the hAT-MSC.sTRAIL could be applicable to the future clinical trials in terms of biosafety. PMID:27151205

  17. Intraoperative Stem Cell Therapy

    OpenAIRE

    Coelho, Mónica Beato; Cabral, Joaquim M. S.; Karp, Jeffrey M.

    2012-01-01

    Stem cells hold significant promise for regeneration of tissue defects and disease-modifying therapies. Although numerous promising stem cell approaches are advancing in clinical trials, intraoperative stem cell therapies offer more immediate hope by integrating an autologous cell source with a well-established surgical intervention in a single procedure. Herein, the major developments in intraoperative stem cell approaches, from in vivo models to clinical studies, are reviewed, and the poten...

  18. Clinical application of temporary crown and cement materials: physical properties and biological safety%临时冠材料及黏结材料的临床应用:物理性能与生物安全性

    Institute of Scientific and Technical Information of China (English)

    聂二民; 姜瑞; 张春元; 曾尽娣; 谈济州

    2015-01-01

    背景:临时冠在临床应用较为广泛,临时冠及其黏结材料随着材料科学的发展不断更新,其临床应用、物理学性能及生物安全性方面也越来越优越.目的:综述临时冠及其黏结材料的临床应用现状、物理性能及生物安全性.方法:以"temporary crown,provisional crown,temporary restoration,provisional restoration,interim restoration"为英文检索词,应用计算机检索PubMed数据库中2004年1月至2014年12月发表的相关文章.纳入与临时冠及其黏结材料相关的研究文献,排除重复性研究.结果与结论:通过临床评价和实验研究得出,临时冠材料自身聚合收缩、聚合产热、单体释放等物理特性和细胞毒性、对软组织的刺激性等生物安全性方面是临床要克服的关键问题.临时冠材料和黏结材料在临床上应用广泛,随着新材料筛选和新制作方法的出现其具有巨大的应用前景和较高的临床价值,但在其实验室研究和临床应用的探索过程中,还有许多亟待解决和深入探究的问题.%BACKGROUND:Temporary crown has been used widely in clinic. The physical properties and biological safety of temporary crown and cement materials are more superior along with the development of material science. OBJECTIVE:To summarize clinical application, physical properties and biological safety of the temporary crown and cement materials. METHODS:PubMed database was searched by the key words of "temporary crown, provisional crown, temporary restoration, provisional restoration, interim restoration" in English to retrieve relevant articles published from January 2004 to December 2014. Literatures addressing the temporary crown and cement materials were included, and the repetitive researches were excluded. RESULTS AND CONCLUSION:Through the clinical evaluation and experimental study, the physical properties (polymerization shrinkage, polymerization heat production, polymerization monomer release) and

  19. Present status and prospect in the clinical use of adult stem cells in tissue repair and regeneration%成体干细胞在组织修复及再生中的治疗现状与展望

    Institute of Scientific and Technical Information of China (English)

    付小兵

    2009-01-01

    Ever since the use of adult stem cells in the field of tissue repair and regeneration, their clinical effects, pos-sible mechanisms and side effects have been questioned. In this article, I review the clinical application of adult stem cells, es-pecially mesenchymal stem cells in functional recovery of skin, acute myocardial infarction and vascular diseases, etc. Mean-whiie, I express my personal opinion on their use in the future.

  20. Modification of Baksi sloppy hinge elbow to minimize the stresses at the humeral bone cement interface- An early experience

    Directory of Open Access Journals (Sweden)

    Baksi D

    2005-01-01

    Full Text Available Background : Baksi sloppy hinge elbow is an all metal prosthesis having 7 0 - 10 0 varus - valgus inherent laxity at the hinge section with minimal motion bearing contact area. Due to the presence of laxity at it′s hinge section, any strain on the prosthesis dissipates primarily to the surrounding soft tissues thus protecting the cement bone interfaces. However, from our long term clinical experiences on the use of our sloppy hinge design since 1984 and the knowledge of literature review of the results of using other semi-constrained (sloppy or unconstrained designs, it was observed that radiolucency or loosening at the bone-cement interface occurred mainly around the humeral stem in the long run due to the continued effect of rotational torque of forearm and hand. Hence, an attempt in the improvement of the design concept is being made. Methods : In this respect one flange each of one cm height and breadth and three mm thickness has been incorporated on either sides of the shank of humeral stem of the sloppy hinge at medio-lateral (coronal plane which will be seated in the corresponding longitudinal groove cut on either side of humeral shaft extending from its transverse cut end to become single assembly during the rotation of humerus. Results : The preliminary results of clinical application of the modified sloppy hinge elbow in ten cases are found satisfactory. Conclusion : The cyclical compression and distraction forces during flexion and extension of the elbow will be distributed over the larger bony area of lower end of humerus where flanges of the humeral shank being seated. The rotational torque effect of forearm and hand particularly with the arm in abduction will be minimised at the humeral bone cement interface as the humerus and the prosthetic stem act as a single assembly by the snugly fitting of the prosthetic flange in the humural shaft

  1. Advancing Stem Cell Biology toward Stem Cell Therapeutics

    OpenAIRE

    Scadden, David; Srivastava, Alok

    2012-01-01

    Here, the International Society for Stem Cell Research (ISSCR) Clinical Translation Committee introduces a series of articles outlining the current status, opportunities, and challenges surrounding the clinical translation of stem cell therapeutics for specific medical conditions.

  2. Tympanoplasty with ionomeric cement

    DEFF Research Database (Denmark)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    isolated erosion of the long incus process have been treated with a new surgical technique in which the ossicular chain was rebuilt with ionomeric cement. The results in hearing performance (mean pure-tone average (PTA) 0.5, 1 and 2 kHz) were evaluated pre- and post-surgery, and compared to those in a...... > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy...

  3. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2003-01-31

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

  4. The King is Dead, Long Live the King: Entering A New Era of Stem Cell Research and Clinical Development

    Directory of Open Access Journals (Sweden)

    Ichim Thomas

    2011-12-01

    Full Text Available Abstract In mid November the biopharma industry was shocked by the announcement from Geron that they were ending work on embryonic stem cell research and therapy. For more than 10 years the public image of all stem cell research has been equated with embryonic stem cells. Unfortunately, a fundamentally important medical and financial fact was being ignored: embryonic stem cell therapy is extremely immature. In parallel to efforts in embryonic stem cell research and development, scientists and physicians in the field of adult stem cells realized that the natural role of adult stem cells in the body is to promote healing and to act like endogenous "repair cells" and, as a result, numerous companies have entered the field of adult stem cell therapy with the goal of expanding numbers of adult stem cells for administration to patients with various conditions. In contrast to embryonic stem cells, which are extremely expensive and potentially dangerous, adult cell cells are inexpensive and have an excellent safety record when used in humans. Many studies are now showing that adult stem cells are practical, patient-applicable, therapeutics that are very close to being available for incorporation into the practice of medicine. These events signal the entrance of the field of stem cells into a new era: an era where hype and misinformation no longer triumph over economic and medical realities.

  5. Stem cell experiments moves into clinic: new hope for children with bronchopulmonary dysplasia.

    Science.gov (United States)

    Pawelec, K; Gładysz, D; Demkow, U; Boruczkowski, D

    2015-01-01

    Bronchopulmonary dysplasia (BPD) is a chronic lung disease with long-term complications that affects mainly preterm born children with low birth weights, especially those treated with mechanical ventilation and oxygen therapy. Successful treatment of BPD could reduce the incidence of other diseases of prematurity such as periventricular leukomalacia and retinopathy. The effects of current therapies are unsatisfactory; thus, searching for novel therapeutic is underway. One promising approach seems administration of mesenchymal stem cells (MSC). Preclinical data strongly support the role of progenitor cells in the preservation of lung structure. MSC can be found more often in pre-term than term umbilical cord and its isolation from Wharton's jelly carries a potential in treating diseases of prematurity. Several questions concerning the use of MSC in BPD remain to be answered, including the amount of transferred cells, intervals between infusions, the best route for administration and the timing. MSC can be administered as a treatment or prophylaxis. However, having in mind that not all prematurely born children are at risk of developing bronchopulmonary dysplasia, a search for laboratory markers identifying potential patients should be conducted. This review summarizes the latest achievements in MSC therapy in the context of BPD. PMID:25252892

  6. Febrile neutropenia in paediatric peripheral blood stem cell transplantation, in vitro sensitivity data and clinical response to empirical antibiotic therapy

    International Nuclear Information System (INIS)

    To find the in-vitro sensitivity data and clinical response in order to determine the changes required in empiric antibiotic therapy for management of febrile neutropenia in paediatric patients undergoing peripheral blood stem cell transplantation. All patients were treated according to institutional protocol for febrile neutropenia. Empirical antibiotics include Ceftriaxone and Amikacin. In non-responders, changes made included Imipenem and Amikacin, Piperacillin Tazobactum/Tiecoplanin or Vancomycin/Cloxacilin/Ceftazidime. In non-responders, amphotaracin was added until recovery. Out of 52 patients, 5 did not develop any fever; in the remaining 47 patients there were 57 episodes of febrile neutropenia. The mean days of febrile episodes were 4.71 (range 3-8). Fever of unknown origin (FUO) occurred in 31 (54.3%) episodes. Microbiologically documented infection (MDI) occurred in 17 (29.8%) episodes of fever. Clinically documented infection (CDI) occurred in 9 (15.7%) episodes. Gram-negative organisms were isolated in 10 while gram-positive organisms in 7. Klebseilla, S. aureus were the most common isolates. Empirical therapy was effective in 12 of the 33 (36%) episodes. Out of 28, 26 (92%) responded to Imipenem/Amikacin as second line therapy while those who received any other second line combination, only 11 out of 22 (50%) showed response. Systemic Amphotericin was used in 4 patients, 2 responded. Infection related mortality rate was 4%. (author)

  7. Early Results of Clinical Application of Autologous Whole Bone Marrow Stem Cell Transplantation for Critical Limb Ischemia with Buerger's Disease.

    Science.gov (United States)

    Heo, Seon-Hee; Park, Yoong-Seok; Kang, Eun-Suk; Park, Kwang-Bo; Do, Young-Soo; Kang, Kyung-Sun; Kim, Dong-Ik

    2016-01-01

    Our goal was to evaluate early results of the clinical application of autologous whole bone marrow stem cell transplantation (AWBMSCT) for critical limb ischemia (CLI) in patients with Buerger's disease. We retrospectively analyzed the data of 58 limbs of 37 patients (mean age, 43.0 years; range, 28-63 years; male, 91.9%) with Buerger's disease with CLI who were treated with AWBMSCT from March 2013 to December 2014. We analyzed Rutherford category, pain score, pain-free walking time (PFWT), total walking time (TWT), ankle brachial pressure index (ABPI), and toe brachial pressure index (TBPI), and investigated wound healing and occurrence of unplanned amputations. The mean follow-up duration was 11.9 ± 7.2 months (range, 0.9-23.9 months) and 100%, 72.4%, and 74.1% of patients were available to follow-up 1, 3 and 6 months after AWBMST, respectively. At 6 months, patients demonstrated significant improvements in Rutherford category (P ABPI was increased compared to baseline, but the difference was not significant. A total of 76.5% ischemic wounds achieved complete or improved healing. AWBMSCT is a safe and effective alternative or adjunctive treatment modality to achieve clinical improvement in patients with CLI. PMID:26791280

  8. Anti-Cancer Stem-like Cell Compounds in Clinical Development – An Overview and Critical Appraisal

    Science.gov (United States)

    Marcucci, Fabrizio; Rumio, Cristiano; Lefoulon, François

    2016-01-01

    Cancer stem-like cells (CSC) represent a subpopulation of tumor cells with elevated tumor-initiating potential. Upon differentiation, they replenish the bulk of the tumor cell population. Enhanced tumor-forming capacity, resistance to antitumor drugs, and metastasis-forming potential are the hallmark traits of CSCs. Given these properties, it is not surprising that CSCs have become a therapeutic target of prime interest in drug discovery. In fact, over the last few years, an enormous number of articles describing compounds endowed with anti-CSC activities have been published. In the meanwhile, several of these compounds and also approaches that are not based on the use of pharmacologically active compounds (e.g., vaccination, radiotherapy) have progressed into clinical studies. This article gives an overview of these compounds, proposes a tentative classification, and describes their biological properties and their developmental stage. Eventually, we discuss the optimal clinical setting for these compounds, the need for biomarkers allowing patient selection, the redundancy of CSC signaling pathways and the utility of employing combinations of anti-CSC compounds and the therapeutic limitations posed by the plasticity of CSCs.

  9. Asphalt cement poisoning

    Science.gov (United States)

    Asphalt; Pavement ... The substances in asphalt that can be harmful are: Hydrocarbons Industrial glues Industrial solvents Tar ... Asphalt is found in: Road paving materials Roofing materials Tile cements Asphalt may also be used for ...

  10. Clinical characteristics and risk factors of Intracranial hemorrhage in patients following allogeneic hematopoietic stem cell transplantation.

    Science.gov (United States)

    Zhang, Xiao-Hui; Wang, Qian-Ming; Chen, Huan; Chen, Yu-Hong; Han, Wei; Wang, Feng-Rong; Wang, Jing-Zhi; Zhang, Yuan-Yuan; Mo, Xiao-Dong; Chen, Yao; Wang, Yu; Chang, Ying-Jun; Xu, Lan-Ping; Liu, Kai-Yan; Huang, Xiao-Jun

    2016-10-01

    Intracranial hemorrhage (ICH) is one of the most life-threatening neurological complications after allogeneic hematopoietic stem cell transplantation. Although cerebral complications and its causes after allo-HSCT are well documented, assessment of the incidence and risk factors of intracranial hemorrhage following allo-HSCT are less discussed. A nested case-control study was conducted involving 160 subjects drawn from 2169 subjects who underwent HSCT at Peking University People's Hospital between 2004 and 2014. Thirty-two patients (1.5 %) with ICH were identified, and 128 controls were matched for age, gender, transplantation type, and time of transplantation. Intracranial hemorrhage was identified by CT scan and/or MRI by searching hospital records. Among the 32 ICH patients, 27 (82.9 %) developed intraparenchymal hemorrhages (IPH), 2 cases (5.7 %) suffered subdural hematomas (SDH), and 3 cases (8.6 %) had multiple hemorrhage lesions in the brain parenchyma. The median time of appearance for cerebral hemorrhages was 147.5 days. Multivariate analysis showed that systemic infections (hazard ratio 2.882, 95 % confidence interval 1.231-6.746), platelet count (5.894, 1.145-30.339), and fibrinogen levels (3.611, 1.528-8.532) were independent risk factors for intracranial hemorrhage among HSCT patients. The cumulative survival rate in the intracranial hemorrhage and control groups were 43.3 and 74.7 % (P = .001), respectively. Intracranial hemorrhage is associated with high mortality and a decreased overall survival rate. Systemic infections, platelet count, and fibrinogen levels were individual independent risk factors. PMID:27485455

  11. Is cementing technique the cause of early aseptic loosening of the tibial component in total knee arthroplasty? A report of 22 failed tibial components

    Directory of Open Access Journals (Sweden)

    Stefan Endres

    2011-05-01

    Full Text Available Despite excellent results of bicondylar knee resurfacing when both the tibial and femoral components are cemented, loosening of the cemented tibial component (surface cementing occurs in approximately 10% of the implants within a 4-year interval after the procedure. Based on our own experience, we want to report of early failed tibial components in 22 patients after a mean follow up of 51 months, necessitating a revision procedure. We analysed retrospectively 22 cases of failed tibial components in patients after a mean follow up of 51 months, necessitating a revision procedure. This raised the question of whether the cementing technique was implicated in the loosening. Every correlation between early loosening and clinically relevant covariates were investigated. All patients were evaluated for radiolucency and osteolytic lesions at the bone–cement interfaces by radiographic assessment according to Rossi et al. (a.p. view and lateral view divided into two zones. The mean radiographic cement penetration in anterior-posterior view was 1.2 mm (SD 0.8 in zone 1 and 1.6 mm (SD 0.9 in zone 2. The mean radiographic cement penetration in lateral view was 1.1 mm (SD 0.4 in zone 1 and 1.3 mm (SD 0.3 in zone 2. Osteolytic lesions were seen in all cases around the implant after a mean of 51 months. In all cases a revision procedure was done. Based on clinical presentation, haematological screening, joint aspiration (synovial fluid diagnostic, microbiological analyses and histological evaluation of intraoperative samples an infection was excluded. The authors have a critical attitude toward a loosening rate of almost 10% as stated by the recent literature within the first 4 to 5 years and consider that a reduction of the loosening rate when using the full cementation technique /cementing the stem will mean a greater benefit for patients than the possible advantage of a better bone stock in case of revision surgery. Apart from this aspect, the question of

  12. Clinical use of Dieletrophoresis separation for live Adipose derived stem cells

    Directory of Open Access Journals (Sweden)

    Wu Allan Y

    2012-05-01

    Full Text Available Abstract Background Microelectrode dieletrophoresis capture of live cells has been explored in animal and cellular models ex-vivo. Currently, there is no clinical data available regarding the safety and efficacy of dielectrophoresis (DEP buffers and microcurrent manipulation in humans, despite copious pre-clinical studies suggesting its safety. The purpose of this study was to determine if DEP isolation of SVF using minimal manipulation methods is safe and efficacious for use in humans using the hand lipotransfer model. Methods Autologous stromal vascular fraction cells (SVF were obtained from lipoaspirate by collagenase digestion and centrifugation. The final mixture of live and dead cells was further processed using a custom DEP microelectrode array and microcurrent generator to isolate only live nucleated cells. Lipotransfer was completed using fat graft enhanced with either standard processed SVF (control versus DEP filtered SVF (experimental. Spectral photography, ultrasound and biometric measurements were obtained at post operatively days 1, 4, 7, 14, 30, 60 and 90. Results The DEP filter was capable of increasing SVF viability counts from 74.3 ± 2.0% to 94.7 ± 2.1%. Surrogate markers of inflammation (temperature, soft tissue swelling, pain and diminished range of motion were more profound on the control hand. Clinical improvement in hand appearance was appreciated in both hands, though the control hand exclusively sustained late phase erosive skin breaks on post operative day 7. No skin breaks were appreciated on the DEP-SVF treated hand. Early fat engraftment failure was noted on the control hand thenar web space at 3 months post surgery. Discussion No immediate hypersensitivity or adverse reaction was appreciated with the DEP-SVF treated hand. In fact, the control hand experienced skin disruption and mild superficial cellulitis, whereas the experimental hand did not experience this complication, suggesting a possible

  13. Modified cementless total coxofemoral prosthesis: development, implantation and clinical evaluation

    Directory of Open Access Journals (Sweden)

    S.A. Arias

    2013-12-01

    Full Text Available The aim of this study was to modify canine coxofemoral prostheses and the clinical evaluation of the implantation. Fifteen canine hips and femora of cadavers were used in order to study the surface points of modification in prostheses and develop a perforation guide. Femoral stems and acetabular components were perforated and coated with biphasic calcium phosphate layer. Twelve young adult male mongrel dogs were implanted with coxofemoral prostheses. Six were operated upon and implanted with cemented canine modular hip prostheses, establishing the control group. The remaining six were implanted with a novel design of cementless porous tricalcic phosphate-hydroxyapatite coated hip prostheses. Clinical and orthopedic performance, complications, and thigh muscular hypotrophy were assessed up to the 120th post-operatory day. After 120 days, animals with cementless prostheses had similar clinical and orthopedic performance compared to the cemented group despite the increased pain thigh hypotrophy. Animals that underwent cementless hip prosthesis evidenced more pain, compared to animals with cemented hip prosthesis that required longer recuperation time. No luxations, two fractures and two isquiatic neurapraxies were identified in the course of the study. Using both the cemented and the bioactive coated cementless model were suitable to dogs, showing clinical satisfactory results. Osseointegration and biological fixation were observed in the animals with the modified cementless hip prosthesis.

  14. The functional performance of orthopaedic bone cement

    Energy Technology Data Exchange (ETDEWEB)

    Prendergast, P.J. [Trinity Coll., Dublin (Ireland). Dept. of Mechanical Engineering

    2001-07-01

    This paper presents a summary of our work on the functional behavior of polymethylmethacrylate as a fixation material for load-bearing implants. Experimental tests on models of hip reconstructions have shown that damage accumulation, in the form of growth of numerous microcracks, occurs in cement-fixated orthopaedic implants. To predict failure due to damage accumulation, fatigue tests of hand-mixed and vacuum-mixed cement are used to determine a relationship between the probability-of-failure, stress, and porosity of the cement. This relationship is then applied to the comparative analysis of orthopaedic implants using finite element analysis. Two implant systems are considered: femoral hip prostheses and glenoid replacement prostheses. It is shown how the complex and intricate stress patterns in the polymethylmethacrylate cement 'mantles' can be analyzed in terms of the probability-of-failure. This allows comparison of implants for pre-clinical testing purposes. The results complement those obtained from clinical studies where subsidence of the implant correlates with implant loosening [Karrholm et al. J. Bone Jt. Surg. Vol. 76B (1994) 912-916]. If subsidence is due to creep, then a correlation between damage accumulation and creep should exist. A basis for such a correlation in polymethylmetacrylate is proposed that links clinical findings of subsidence with our results with regard to damage accumulation. (orig.)

  15. Retention of overdenture posts cemented with self-adhesive resin cements.

    Science.gov (United States)

    Elsayed, Mohamed Ezzat; El-Mowafy, Omar; Fenton, Aaron

    2009-01-01

    This study investigated the effects of two self-adhesive resin cements on the retention of overdenture anchor posts after 30 days of aging in water. Forty caries-free human canines were randomly assigned to four test groups. Uni-Anchor posts were cemented to specimens in groups A and B with Breeze and Maxcem self-adhesive resin cements, respectively. In groups C and D, Fuji glass-ionomer cement and Fleck's zinc phosphate cement were used, respectively. Specimens were stored in distilled water at 37 degrees C for 30 days. Each specimen was loaded in tension in an Instron universal testing machine. The maximum force required to dislodge each post was recorded. Means and standard deviations (SDs) were calculated and data were statistically analyzed with analysis of variance (ANOVA). Means and SDs were 706.5 +/- 204.6 N for Breeze, 585.1 +/- 213.5 N for Maxcem, 449.2 +/- 181.1 N for Fuji, and 330.4 +/- 120.6 N for Fleck's. ANOVA revealed significant differences among the means (P Breeze cement (group A) resulted in the highest retention force and most frequent cohesive failure and thus would be expected to clinically perform in a superior manner. PMID:19548412

  16. Seepage/Cement Interactions

    International Nuclear Information System (INIS)

    The Development Plan (CRWMS M andO 1999a) pertaining to this task defines the work scopes and objectives for development of various submodels for the Physical and Chemical Environment Abstraction Model for TSPA-LA. The Development Plan (CRWMS M andO 1999a) for this specific task establishes that an evaluation be performed of the chemical reactions between seepage that has entered the drift and concrete which might be used in the repository emplacement drifts. The Development Plan (CRWMS M andO 1999a) then states that the potential effects of these water/grout reactions on chemical conditions in the drift be assessed factoring in the influence of carbonation and the relatively small amount of grout. This task is also directed at: (1) developing a conceptualization of important cement/seepage interactions and potential impacts on EBS performance, (2) performing a screening analysis to assess the importance of cement/seepage interactions. As the work progresses and evolves on other studies, specifically the Engineered Barrier System: Physical and Chemical Environment (P andCE) Model (in progress), many of the issues associated with items 1 and 2, above, will be assessed. Such issues include: (1) Describing the mineralogy of the specified cementitious grout and its evolution over time. (2) Describing the composition of the water before contacting the grout. (3) Developing reasonable upper-bound estimates for the composition of water contacting grout, emphasizing pH and concentrations for anions such as sulfate. (4) Evaluating the equilibration of cement-influenced water with backfill and gas-phase CO2. (5) Developing reasonable-bound estimates for flow rate of affected water into the drift. The concept of estimating an ''upper-bound'' range for reaction between the grout and the seepage, particularly in terms of pH is based on equilibrium being established between the seepage and the grout. For example, this analysis can be based on equilibrium being established as

  17. Clinical significance of measurement of serum NSE, NPY and TNF-α levels in pediatric patients with hand-foot and mouth disease complicated with brain stem encephalitis

    International Nuclear Information System (INIS)

    Objective: To explore the clinical significance of changes of serum NSE, NPY and TNF-α levels in pediatric patients with hand-foot and mouth disease complicated with brain stem encephalitis. Methods: Serum NSE, NPY and TNF-α levels were determined with RIA in 34 pediatric patients with hand-foot and mouth disease complicated with brain stem encephalitis and 30 controls. Results: The serum NSE, NPY and TNF-α levels in the patients were significantly higher than those in controls (P<0.01), Serum TNF-α and NSE, NPY levels were mutually positively correlated (r=0.4716, 0.5184, P<0.01). Conclusion: Detection of NSE, NPY and TNF-α levels was helpful for the prediction of treatment efficacy in patients with hand-foot and mouth disease complicated with brain stem encephalitis. (authors)

  18. Symptomatic knee osteoarthritis treatment using autologous adipose derived stem cells and platelet-rich plasma: a clinical study

    OpenAIRE

    Phuc Van Pham; Khanh Hong-Thien Bui; Triet Dinh Duong; Nhan Thanh Nguyen; Thanh Duc Nguyen; Vien Tuong Le; Viet Thanh Mai; Nhan Lu-Chinh Phan; Dung Minh Le and Ngoc Kim Ngoc

    2014-01-01

    Osteoarthritis is one of the most common diseases, and it affects 12% of the population around the world. Although the disease is chronic, it significantly reduces the patient's quality of life. At present, stem cell therapy is considered to be an efficient approach for treating this condition. Mesenchymal stem cells (MSCs) show the most potential for stem cell therapy of osteoarthritis. In fact, MSCs can differentiate into certain mesodermal tissues such as cartilage and bone. Therefore, in ...

  19. Clinical outcomes of osteonecrosis of the femoral head after autologous bone marrow stem cell implantation: a meta-analysis of seven case-control studies

    Directory of Open Access Journals (Sweden)

    Heng-feng Yuan

    2016-02-01

    Full Text Available The purpose of this study was to evaluate the clinical outcomes of osteonecrosis of the femoral head after autologous bone marrow stem cell implantation. We searched the PubMed, Embase and Web of Science databases and included all case-control trials that reported on the clinical outcomes of osteonecrosis progression, incidence of total hip arthroplasty and improvement in Harris hip scores. Overall, seven case-control trials were included. Compared with the controls, patients treated with the bone marrow stem cells implantation treatment showed improved clinical outcomes with delayed osteonecrosis progression (odds ratio = 0.17, 95% CI: 0.09 - 0.32; p<0.001, a lower total hip arthroplasty incidence (odds ratio = 0.30, 95% CI: 0.12 - 0.72; p<0.01 and increased Harris hip scores (mean difference = 4.76, 95% CI: 1.24 - 8.28; p<0.01. The heterogeneity, publication bias, and sensitivity analyses showed no statistical difference significant differences between studies. Thus, our study suggests that autologous bone marrow stem cells implantation has a good therapeutic effect on osteonecrosis of the femoral, resulting in beneficial clinical outcomes. However, trials with larger sample sizes are needed to confirm these findings.

  20. Clinical outcomes of osteonecrosis of the femoral head after autologous bone marrow stem cell implantation: a meta-analysis of seven case-control studies.

    Science.gov (United States)

    Yuan, Heng-Feng; Zhang, Jing; Guo, Chang-An; Yan, Zuo-Qin

    2016-02-01

    The purpose of this study was to evaluate the clinical outcomes of osteonecrosis of the femoral head after autologous bone marrow stem cell implantation. We searched the PubMed, Embase and Web of Science databases and included all case-control trials that reported on the clinical outcomes of osteonecrosis progression, incidence of total hip arthroplasty and improvement in Harris hip scores. Overall, seven case-control trials were included. Compared with the controls, patients treated with the bone marrow stem cells implantation treatment showed improved clinical outcomes with delayed osteonecrosis progression (odds ratio = 0.17, 95% CI: 0.09 - 0.32; p <0.001), a lower total hip arthroplasty incidence (odds ratio = 0.30, 95% CI: 0.12 - 0.72; p <0.01) and increased Harris hip scores (mean difference = 4.76, 95% CI: 1.24 - 8.28; p<0.01). The heterogeneity, publication bias, and sensitivity analyses showed no statistical difference significant differences between studies. Thus, our study suggests that autologous bone marrow stem cells implantation has a good therapeutic effect on osteonecrosis of the femoral, resulting in beneficial clinical outcomes. However, trials with larger sample sizes are needed to confirm these findings. PMID:26934241

  1. Experimental study with domestic bone cement in the percutaneous vertebroplasty

    International Nuclear Information System (INIS)

    Objective: To study the feasibility of injecting domestic bone cement in the process of the percutaneous vertebroplasty. Methods: (1) Various types cement were disposed with domestic PMMA. The concretionary phases of cement were observed according to the stages and holding time. Then the most ideal ratio of the mixed cement was selected and ten cement columns were made with this ratio, which was taken as the trial group. The other ten referring to was taken as the contrast one. The biological mechanics was measured with a load and the data of the results were compared. (2) Twenty thoracic and lumbar adjacent bodies were removed intact from five human corpses. These bodies were divided into two groups, in one group PMMA were injected, the other was severed as the contrast one. Then in these twenty vertebral bodies the biological mechanics was measured and the treatment effect was evaluated. (3) In 12 healthy dogs PVP in lumber was tried so as to observe the operational difficulty during the process of injected this bone cement and CT was used to evaluate the result of PMMA, diffusion and the complications caused by it. Results: The most ideal ratio was 4:2.6:1 (g, ml, ml) between powder, monome and contrast. After injecting this kind of cement, the loading strength of these vertebral bodies was increased remarkably (P<0.01). Conclusion: Injecting domestic bone cement provides the theoretical foundations for the clinical application of PVP. (author)

  2. Editorial: Stem Cell Engineering.

    Science.gov (United States)

    Cabral, Joaquim M S; Palecek, Sean P

    2015-10-01

    In recent years, the promise of stem cells as tools for basic research, in vitro diagnostics, and in vivo therapeutics is increasingly being realized. This Special issue of Biotechnology Journal explores recent advances in the emerging field of stem cell engineering, with a focus on applying engineering approaches to understanding stem cell biology and enabling translation of stem cells to commercial and clinical products. PMID:26447639

  3. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  4. Clinical observation of screw and cement-retained implant-supported restoration of fixed bridges%2种固位方式在种植体支持固定桥中的应用比较

    Institute of Scientific and Technical Information of China (English)

    宋涛; 徐培成; 李煜

    2011-01-01

    PURPOSE: To compare the prosthetic outcome of screw- and cement-retained implant-supported restorations of the fixed bridges. METHODS: A total of 185 Straumann implants were placed in the alveolar bone of 68 partially edentulous patients from Jan. 2006 to Dec. 2007. All of them were 2 to 6 units of combination crowns with Straumann system. Then they were followed up for 3 years. In each group, the retention, influence on hard and soft tissues, passive fitting and rupture strength of the ceramic layer were evaluated. The data was analyzed with SPSS12.0 software package. RESULTS: There were more advantages of retention and the rupture strength of the ceramic layer in the cement-retained group, while there was less influence on the hard and soft tissues, and more facility of maintenance and reparation in the screwed-retained group. The difference between the two groups was statistically not significant (P>0.05). CONCLUSIONS; The clinical outcomes of implant restorations are satisfactory, either screw-retained or cement-retained. Cement retention is used in 2 to 3 unit combination crowns, while screw retention is more suitable for complicated cases.%目的:评价螺丝固位和黏结固位在种植体联合修复中的临床应用效果.方法:2006年1月-2007年12月间,共为66例患者植入185颗Straumann种植体,均为2-6颗的联冠修复.随访3a,从固位效果、对软硬组织的影响、被动就位及瓷层的抗折能力等临床指标对2种修复方式进行评价.采用SPSS12.0软件包对数据进行统计学分析.结果:黏结固位方式在固位效果及瓷层的抗折能力上较好,螺丝固位在软组织的影响和维护修理的便利性上效果较好,但均无统计学差异.结论:在种植固定桥修复中,螺丝固位与黏结固位均为有效可靠的修复方式.黏结固位在2~3个单位的简单联冠修复上占有优势,而螺丝固位更适合于复杂病例的修复.

  5. STEM, STEM Education, STEMmania

    Science.gov (United States)

    Sanders, Mark

    2009-01-01

    In this article, the author introduces integrative STEM (science, technology, engineering, and/or mathematics) education and discusses the importance of the program. The notion of integrative STEM education includes approaches that explore teaching and learning between/among any two or more of the STEM subject areas, and/or between a STEM subject…

  6. PART II. HYDRATED CEMENTS

    Directory of Open Access Journals (Sweden)

    Milan Drabik

    2014-09-01

    Full Text Available Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions - ΔH, of technological materials based on two types of Portland cements. The values of thermoanalytical events and also ΔH of probes of technological compositions, if related with the data of a choice of minerals of calcium-silicate-sulfate-aluminate hydrates, served as a valued input for the assessment of phases present and phase changes due to the topical hydraulic processes. The results indicate mainly the effects of "standard humidity" or "wet storage" of the entire hydration/hydraulic treatment, but also the presence of cement residues alongside calcium-silicate-sulfate-aluminate hydrates (during the tested period of treatment. "A diluting" effect of unhydrated cement residues upon the values of decomposition enthalpies in the studied multiphase system is postulated and discussed

  7. Technology Roadmaps: Cement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    To support its roadmap work focusing on key technologies for emissions reductions, the International Energy Agency (IEA) also investigated one particular industry: cement. Cement production includes technologies that are both specific to this industry and those that are shared with other industries (e.g., grinding, fuel preparation, combustion, crushing, transport). An industry specific roadmap provides an effective mechanism to bring together several technology options. It outlines the potential for technological advancement for emissions reductions in one industry, as well as potential cross-industry collaboration.

  8. Concrete = aggregate, cement, water?

    International Nuclear Information System (INIS)

    Concrete for the Temelin nuclear power plant is produced to about 70 different formulae. For quality production, homogeneous properties of aggregates, accurate proportioning devices, technological discipline and systematic inspections and tests should be assured. The results are reported of measuring compression strength after 28 days for different concrete samples. The results of such tests allow reducing the proportion of cement, which brings about considerable savings. Reduction in cement quantities can also be achieved by adding ash to the concrete mixes. Ligoplast, a plasticizer addition is used for improving workability. (M.D). 8 figs

  9. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  10. Extended fatigue life of a catalyst-free self-healing acrylic bone cement using microencapsulated 2-octyl cyanoacrylate

    OpenAIRE

    Brochu, Alice B. W.; Matthys, Oriane B.; Craig, Stephen L.; Reichert, William M.

    2014-01-01

    The tissue adhesive 2-octyl cyanoacrylate (OCA) was encapsulated in polyurethane microshells and incorporated into bone cement to form a catalyst free, self-healing bone cement comprised of all clinically approved components. The bending strength, modulus, and fatigue lifetime were investigated in accordance with ASTM and ISO standards for the testing of PMMA bone cement. The bending strength of bone cement specimens decreased with increasing wt% capsules content for capsules without or with ...

  11. Porous surface modified bioactive bone cement for enhanced bone bonding.

    Directory of Open Access Journals (Sweden)

    Qiang He

    Full Text Available BACKGROUND: Polymethylmethacrylate bone cement cannot provide an adhesive chemical bonding to form a stable cement-bone interface. Bioactive bone cements show bone bonding ability, but their clinical application is limited because bone resorption is observed after implantation. Porous polymethylmethacrylate can be achieved with the addition of carboxymethylcellulose, alginate and gelatin microparticles to promote bone ingrowth, but the mechanical properties are too low to be used in orthopedic applications. Bone ingrowth into cement could decrease the possibility of bone resorption and promote the formation of a stable interface. However, scarce literature is reported on bioactive bone cements that allow bone ingrowth. In this paper, we reported a porous surface modified bioactive bone cement with desired mechanical properties, which could allow for bone ingrowth. MATERIALS AND METHODS: The porous surface modified bioactive bone cement was evaluated to determine its handling characteristics, mechanical properties and behavior in a simulated body fluid. The in vitro cellular responses of the samples were also investigated in terms of cell attachment, proliferation, and osteoblastic differentiation. Furthermore, bone ingrowth was examined in a rabbit femoral condyle defect model by using micro-CT imaging and histological analysis. The strength of the implant-bone interface was also investigated by push-out tests. RESULTS: The modified bone cement with a low content of bioactive fillers resulted in proper handling characteristics and adequate mechanical properties, but slightly affected its bioactivity. Moreover, the degree of attachment, proliferation and osteogenic differentiation of preosteoblast cells was also increased. The results of the push-out test revealed that higher interfacial bonding strength was achieved with the modified bone cement because of the formation of the apatite layer and the osseointegration after implantation in the bony

  12. The clinical effects of osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation%骨质疏松腰椎退行性疾病的手术治疗分析

    Institute of Scientific and Technical Information of China (English)

    孔祥瑞; 刘德政; 刘海峰; 杨计策; 赵志超

    2015-01-01

    ObjectiveTo explore the clinical effects of osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. Methods 82 cases of patients with lumbar degenerative dis-ease of osteoporosis word randomly divided into experiment group(41 cases) and control group(41 cases). The control group were treated by transpedicle screws fixation, the experiment group were treated by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. The time of operation, mean bleeding volum, the scores of VAS, ODI, JOA were com-pared for the two groups. ResultsThe time of operation, mean bleeding volum for the experiment group were better than the control group; There was no significant difference on the scores of VAS, ODI, JOA; The scores of VAS, ODI for the experiment group were lower than the control group postoperation for 1 week, 2 months, 12 months; The scores of JOA for the experiment group were higher than the control group postoperation for 1 week, 2 months, 12 months. ConclusionIt can improve the scores of VAS, ODI, JOA for the patients with osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. It is worthy of clinical promotion.%目的:探讨可注射硫酸钙骨水泥强化椎弓根钉内固定治疗骨质疏松腰椎退行性疾病的临床疗效。方法:按照随机数字表法将我院收治的82例骨质疏松腰椎退行性疾病患者均分为实验组和对照组,对照组给予单纯椎弓根内固定治疗,实验组给予可注射硫酸钙骨水泥强化椎弓根钉内固定治疗。比较两组患者手术时间、术中出血量以及治疗前后疼痛视觉模拟评分(VAS)、Oswestry 功能障碍指数(ODI)、JOA 腰椎病疗效评分变化情况。结果:实验组患者手术时间和术中出血量显著高于对照组;两组患者术前 VAS 评分、ODI 评分、JOA

  13. Generation of clinical-grade CD19-specific CAR-modified CD8+ memory stem cells for the treatment of human B-cell malignancies.

    Science.gov (United States)

    Sabatino, Marianna; Hu, Jinhui; Sommariva, Michele; Gautam, Sanjivan; Fellowes, Vicki; Hocker, James D; Dougherty, Sean; Qin, Haiying; Klebanoff, Christopher A; Fry, Terry J; Gress, Ronald E; Kochenderfer, James N; Stroncek, David F; Ji, Yun; Gattinoni, Luca

    2016-07-28

    Long-lived, self-renewing, multipotent T memory stem cells (TSCM) can trigger profound and sustained tumor regression but their rareness poses a major hurdle to their clinical application. Presently, clinically compliant procedures to generate relevant numbers of this T-cell population are undefined. Here, we provide a strategy for deriving large numbers of clinical-grade tumor-redirected TSCM starting from naive precursors. CD8(+)CD62L(+)CD45RA(+) naive T cells enriched by streptamer-based serial-positive selection were activated by CD3/CD28 engagement in the presence of interleukin-7 (IL-7), IL-21, and the glycogen synthase-3β inhibitor TWS119, and genetically engineered to express a CD19-specific chimeric antigen receptor (CD19-CAR). These conditions enabled the generation of CD19-CAR-modified CD8(+) TSCM that were phenotypically, functionally, and transcriptomically equivalent to their naturally occurring counterpart. Compared with CD8(+) T cells generated with clinical protocols currently under investigation, CD19-CAR-modified CD8(+) TSCM exhibited enhanced metabolic fitness and mediated robust, long-lasting antitumor responses against systemic acute lymphoblastic leukemia xenografts. This clinical-grade platform provides the basis for a phase 1 trial evaluating the activity of CD19-CAR-modified CD8(+) TSCM in patients with B-cell malignancies refractory to prior allogeneic hematopoietic stem cell transplantation. PMID:27226436

  14. Low-modulus PMMA bone cement modified with castor oil

    OpenAIRE

    López, Alejandro; Hoess, Andreas; Thersleff, Thomas; Ott, Marjam; Engqvist, Håkan; Persson, Cecilia

    2011-01-01

    Some of the current clinical and biomechanical data suggest that vertebroplasty causes the development of adjacent vertebral fractures shortly after augmentation. These findings have been attributed to high injection volumes as well as high Young’s moduli of PMMA bone cements compared to that of the osteoporotic cancellous bone. The aim of this study was to evaluate the use of castor oil as a plasticizer for PMMA bone cements. The Young’s modulus, yield strength, maximum polymerization temper...

  15. Stem Cells

    Science.gov (United States)

    Stem cells are cells with the potential to develop into many different types of cells in the body. ... the body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

  16. A defined and xeno-free culture method enabling the establishment of clinical-grade human embryonic, induced pluripotent and adipose stem cells.

    Directory of Open Access Journals (Sweden)

    Kristiina Rajala

    Full Text Available BACKGROUND: The growth of stem cells in in vitro conditions requires optimal balance between signals mediating cell survival, proliferation, and self-renewal. For clinical application of stem cells, the use of completely defined conditions and elimination of all animal-derived materials from the establishment, culture, and differentiation processes is desirable. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report the development of a fully defined xeno-free medium (RegES, capable of supporting the expansion of human embryonic stem cells (hESC, induced pluripotent stem cells (iPSC and adipose stem cells (ASC. We describe the use of the xeno-free medium in the derivation and long-term (>80 passages culture of three pluripotent karyotypically normal hESC lines: Regea 06/015, Regea 07/046, and Regea 08/013. Cardiomyocytes and neural cells differentiated from these cells exhibit features characteristic to these cell types. The same formulation of the xeno-free medium is capable of supporting the undifferentiated growth of iPSCs on human feeder cells. The characteristics of the pluripotent hESC and iPSC lines are comparable to lines derived and cultured in standard undefined culture conditions. In the culture of ASCs, the xeno-free medium provided significantly higher proliferation rates than ASCs cultured in medium containing allogeneic human serum (HS, while maintaining the differentiation potential and characteristic surface marker expression profile of ASCs, although significant differences in the surface marker expression of ASCs cultured in HS and RegES media were revealed. CONCLUSION/SIGNIFICANCE: Our results demonstrate that human ESCs, iPSCs and ASCs can be maintained in the same defined xeno-free medium formulation for a prolonged period of time while maintaining their characteristics, demonstrating the applicability of the simplified xeno-free medium formulation for the production of clinical-grade stem cells. The basic xeno-free formulation

  17. Optimizing patient derived mesenchymal stem cells as virus carriers for a Phase I clinical trial in ovarian cancer

    Directory of Open Access Journals (Sweden)

    Mader Emily K

    2013-01-01

    Full Text Available Abstract Background Mesenchymal stem cells (MSC can serve as carriers to deliver oncolytic measles virus (MV to ovarian tumors. In preparation for a clinical trial to use MSC as MV carriers, we obtained cells from ovarian cancer patients and evaluated feasibility and safety of this approach. Methods MSC from adipose tissues of healthy donors (hMSC and nine ovarian cancer patients (ovMSC were characterized for susceptibility to virus infection and tumor homing abilities. Results Adipose tissue (range 0.16-3.96 grams from newly diagnosed and recurrent ovarian cancer patients yielded about 7.41×106 cells at passage 1 (range 4–9 days. Phenotype and doubling times of MSC were similar between ovarian patients and healthy controls. The time to harvest of 3.0×108 cells (clinical dose could be achieved by day 14 (range, 9–17 days. Two of nine samples tested had an abnormal karyotype represented by trisomy 20. Despite receiving up to 1.6×109 MSC/kg, no tumors were seen in SCID beige mice and MSC did not promote the growth of SKOV3 human ovarian cancer cells in mice. The ovMSC migrated towards primary ovarian cancer samples in chemotaxis assays and to ovarian tumors in athymic mice. Using non-invasive SPECT-CT imaging, we saw rapid co-localization, within 5–8 minutes of intraperitoneal administration of MV infected MSC to the ovarian tumors. Importantly, MSC can be pre-infected with MV, stored in liquid nitrogen and thawed on the day of infusion into mice without loss of activity. MV infected MSC, but not virus alone, significantly prolonged the survival of measles immune ovarian cancer bearing animals. Conclusions These studies confirmed the feasibility of using patient derived MSC as carriers for oncolytic MV therapy. We propose an approach where MSC from ovarian cancer patients will be expanded, frozen and validated to ensure compliance with the release criteria. On the treatment day, the cells will be thawed, washed, mixed with virus, briefly

  18. Produktie van cement

    NARCIS (Netherlands)

    Smit JRK; Coenen PWHG; Matthijsen AJCM; LAE; TAUW

    1995-01-01

    This document on cement production has been published within the SPIN project. In this project information has been collected on industrial plants or industrial processes to afford support to governmental policy on emission reduction. This document contains information on the processes, emission sou

  19. Clinical observation of umbilical cord mesenchymal stem cell transplantation in treatment for sequelae of thoracolumbar spinal cord injury

    OpenAIRE

    Cheng, Hongbin; Liu, Xuebin; Hua, Rongrong; Dai, Guanghui; Wang, Xiaodong; Gao, Jianhua; An, Yihua

    2014-01-01

    Background Umbilical cord mesenchymal stem cells (UCMSCs) have a considerable advantage and potential in treating for central nervous system diseases and have become a novel alternative treatment for spinal cord injury. This study aims to compare the neurological function outcome of stem cell transplantation, rehabilitation therapy, and self-healing for sequelae of spinal cord injury. Methods Thirty-four cases of thoracolumbar spinal cord injury were randomly divided into three groups: the st...

  20. Conventional and Contemporary Luting Cements: An Overview

    OpenAIRE

    Ladha, Komal; Verma, Mahesh

    2010-01-01

    Long-term clinical success of fixed prosthodontic restorations is influenced by many factors, one important factor being the selection of an appropriate luting agent. No single luting agent is capable of meeting all the stringent requirements, which is one reason why there is such a wide choice of luting agents currently available from conventional water-based to contemporary adhesive resin cements. Introduction of adhesive resin systems has completely changed the face of fixed prosthodontic ...

  1. Relationships between stem cells and cancer stem cells

    OpenAIRE

    Crowe, D.L.; Parsa, B.; Sinha, U.K.

    2004-01-01

    Stem cells have been shown to exist in a variety of tissues. Recent studies have characterized stem cell gene expression patterns, phenotypes, and potential therapeutic uses. One of the most important properties of stem cells is that of self renewal. This raises the possibility that some of the clinical properties of human tumors may be due to transformed stem cells. Similar signaling pathways may regulate self renewal in normal and transformed stem cells. Thes...

  2. Clinical Effects of Novel Nanoscaled Core Decompression Rods Combined with Umbilical Cord Mesenchymal Stem Cells on the Treatment of Early Osteonecrosis of the Femoral Head

    Directory of Open Access Journals (Sweden)

    Hongyang Gao

    2015-01-01

    Full Text Available Osteonecrosis of the femoral head (ONFH is one of the most common diseases in orthopedics. In this study, we investigated the clinical effects of novel nanoscaled core decompression rods combined with mesenchymal stem cells on the treatment of the ONFH. 12 adult patients with early ONFH (at the stage of Ficat II received the treatment using the implantation of novel nanoscaled core decompression rods combined with umbilical cord mesenchymal stem cells. The grade of the patients’ hip was scored by Harris marking system before and after the surgery, and then paired t-test was done. We assessed the curative efficiency based on the change of the patients before and after the surgery. In particular, the survival rate of femoral head was assessed at 12 months after the surgery. The results demonstrated that according to the standard of Harris Scoring, the average grade of hip joint before the surgery was 54.16 ± 4.23 points while average grade of hip joint at 12 months after the surgery was 85.28 ± 3.65 points. So, the implantation of the novel nanoscaled core decompression rods combined with mesenchymal stem cells had satisfactory clinical effects, suggesting that this implantation should be effective to treat early ONFH.

  3. STEM, STEM Education, STEMmania

    OpenAIRE

    Sanders, Mark E.

    2008-01-01

    A series of circumstances has once more created an opportunity for technology educators to develop and implement new integrative approaches to STEM education championed by STEM education reform doctrine over the past two decades.

  4. Comparison of Clinical and Radiographic Success Rate of Ferric Sulfate Pulpotomy Method in Second Primary Molars Using Zinc Oxide Eugenol and Zinc Polycarboxylate Cements.

    OpenAIRE

    N Ramazani; H. Neamatollahi

    2008-01-01

    Introduction: Ferric sulfate pulpotomy is a safe and effective method of the pulpotomy of primary teeth. But the results of different studies indicate low success rate of ferric sulfate pulpotomy in comparison to Formocresol pulpotomy and a portion of these failures may be related to stimulating and harmful effects of zinc oxide Eugenol paste. The aim of this study was to determine and compare the clinical and radiographic success rate of ferric sulfate pulpotomy of primary molars with zinc o...

  5. FLT3 mutations in early T-cell precursor ALL characterize a stem cell like leukemia and imply the clinical use of tyrosine kinase inhibitors.

    Directory of Open Access Journals (Sweden)

    Martin Neumann

    Full Text Available Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL has been identified as high-risk subgroup of acute T-lymphoblastic leukemia (T-ALL with a high rate of FLT3-mutations in adults. To unravel the underlying pathomechanisms and the clinical course we assessed molecular alterations and clinical characteristics in a large cohort of ETP-ALL (n = 68 in comparison to non-ETP T-ALL adult patients. Interestingly, we found a high rate of FLT3-mutations in ETP-ALL samples (n = 24, 35%. Furthermore, FLT3 mutated ETP-ALL was characterized by a specific immunophenotype (CD2+/CD5-/CD13+/CD33-, a distinct gene expression pattern (aberrant expression of IGFBP7, WT1, GATA3 and mutational status (absence of NOTCH1 mutations and a low frequency, 21%, of clonal TCR rearrangements. The observed low GATA3 expression and high WT1 expression in combination with lack of NOTCH1 mutations and a low rate of TCR rearrangements point to a leukemic transformation at the pluripotent prothymocyte stage in FLT3 mutated ETP-ALL. The clinical outcome in ETP-ALL patients was poor, but encouraging in those patients with allogeneic stem cell transplantation (3-year OS: 74%. To further explore the efficacy of targeted therapies, we demonstrate that T-ALL cell lines transfected with FLT3 expression constructs were particularly sensitive to tyrosine kinase inhibitors. In conclusion, FLT3 mutated ETP-ALL defines a molecular distinct stem cell like leukemic subtype. These data warrant clinical studies with the implementation of FLT3 inhibitors in addition to early allogeneic stem cell transplantation for this high risk subgroup.

  6. In vitro evaluation of microleakage of various types of dental cements

    OpenAIRE

    Medić Vesna; Obradović-Đuričić Kosovka; Dodić Slobodan; Petrović Renata

    2010-01-01

    Introduction. Microleakage is defined as the clinically undetectable seepage of oral fluids containing bacteria and debris between cement layer and tooth restoration. Objective. This in vitro study investigated the effect of different dental cements (zinc-phosphate, polycarboxylate, glass-ionomer and resin cement) on microleakage in different ceramic crown systems (metal ceramic crown, metal ceramic crown with a porcelain margin, Empress 2 and In Ceram all-ceramic crowns) fixed on extracted h...

  7. US cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Nisbet, M.A.

    1997-12-31

    This paper describes the cement and concrete industry, and provides data on energy use and carbon dioxide emissions. The potential impact of an energy tax on the industry is briefly assessed. Opportunities identified for reducing carbon dioxide emissions include improved energy efficiency, alternative fuels, and alternative materials. The key factor in determining CO{sub 2} emissions is the level of domestic production. The projected improvement in energy efficiency and the relatively slow growth in domestic shipments indicate that CO{sub 2} emissions in 2000 should be about 5% above the 1990 target. However, due to the cyclical nature of cement demand, emissions will probably be above target levels during peak demand and below target levels during demand troughs. 7 figs., 2 tabs.

  8. Silver-Doped Calcium Phosphate Bone Cements with Antibacterial Properties

    Science.gov (United States)

    Rau, J. V.; Fosca, M.; Graziani, V.; Egorov, A. A.; Zobkov, Yu. V.; Fedotov, A. Yu.; Ortenzi, M.; Caminiti, R.; Baranchikov, A. E.; Komlev, V. S.

    2016-01-01

    Calcium phosphate bone cements (CPCs) with antibacterial properties are demanded for clinical applications. In this study, we demonstrated the use of a relatively simple processing route based on preparation of silver-doped CPCs (CPCs-Ag) through the preparation of solid dispersed active powder phase. Real-time monitoring of structural transformations and kinetics of several CPCs-Ag formulations (Ag = 0 wt %, 0.6 wt % and 1.0 wt %) was performed by the Energy Dispersive X-ray Diffraction technique. The partial conversion of β-tricalcium phosphate (TCP) phase into the dicalcium phosphate dihydrate (DCPD) took place in all the investigated cement systems. In the pristine cement powders, Ag in its metallic form was found, whereas for CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, CaAg(PO3)3 was detected and Ag (met.) was no longer present. The CPC-Ag 0 wt % cement exhibited a compressive strength of 6.5 ± 1.0 MPa, whereas for the doped cements (CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt %) the reduced values of the compressive strength 4.0 ± 1.0 and 1.5 ± 1.0 MPa, respectively, were detected. Silver-ion release from CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, measured by the Atomic Emission Spectroscopy, corresponds to the average values of 25 µg/L and 43 µg/L, respectively, rising a plateau after 15 days. The results of the antibacterial test proved the inhibitory effect towards pathogenic Escherichia coli for both CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, better performances being observed for the cement with a higher Ag-content. PMID:27096874

  9. Performance of Cement Containing Laterite as Supplementary Cementing Material

    Directory of Open Access Journals (Sweden)

    Abbas Bukhari, Z. S.

    2013-03-01

    Full Text Available The utilization of different industrial waste, by-products or other materials such as ground granulated blast furnace slag, silica fume, fly ash, limestone, and kiln dust, etc. as supplemen- tary cementing materials has received considerable attention in recent years. A study has been conducted to look into the performance of laterite as Supplementary Cementing Materials (SCM. The study focuses on compressive strength performance of blended cement containing different percentage of laterite. The cement is replaced accordingly with percentage of 2 %, 5 %, 7 % and 10 % by weight. In addition, the effect of use of three chemically different laterites have been studied on physical performance of cement as in setting time, Le-Chatlier expansion, loss on ignition, insoluble residue, free lime and specifically compressive strength of cement cubes tested at the age of 3, 7, and 28 days. The results show that the strength of cement blended with laterite as SCM is enhanced. Key words: Portland cement, supplementary cementing materials (SCM, laterite, compressive strength KUI – 6/2013 Received January 4, 2012 Accepted February 11, 2013

  10. Tympanoplasty with ionomeric cement.

    Science.gov (United States)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    Patients with isolated erosion of the long incus process suffer from severe hearing loss caused by lack of continuity of the ossicular chain. This study is a retrospective evaluation of the hearing results using two different surgical procedures. Since January 1993, 12 consecutive patients with isolated erosion of the long incus process have been treated with a new surgical technique in which the ossicular chain was rebuilt with ionomeric cement. The results in hearing performance (mean pure-tone average (PTA) 0.5, 1 and 2 kHz) were evaluated pre- and post-surgery, and compared to those in a group of 20 historical controls who underwent surgery in 1991 and 1992 using incus autograft interposition. Among the 12 index patients, 7 (58%) achieved improvement in PTA of > 10 dB, in 3 there was no difference and in 2 a slight decline. Among the 20 controls, 14 (70%) achieved improvement in PTA of > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy to perform, presents less risk of damage to the stapes and cochlea, requires less extensive surgery and does not exclude other surgical methods in cases of reoperation. PMID:10909000

  11. Processes and Equipment for the Cementation of Radioactive Waste

    International Nuclear Information System (INIS)

    In this article a short selection of different cement mixer types provided by NUKEM Technologies is given. The variety stems on one hand from historical development, but more especially from specific customer demands to meet their local and technical requirements. The Slant Batch Mixer is successfully installed in several Waste Treatment Centers (WTC). NUKEM Technologies set up these mixers with necessary auxiliary systems to facilitate all the cementation tasks of a WTC. By the slant design of the mixer a homogeneous intermixing and a rapid and comprehensive emptying is achieved. The High Shear Mixer is a batch mixer producing a thixotropic, fast flowing colloidal cement slurry. NUKEM Technologies uses this cement slurry to bubble-free/ empty space-free grouting of pre-packed solid waste items in container. The High Throughput Continuous Mixer is a continuously operating screw mixer that provides a high throughput. One or more dry components are continuously fed to the mixer where liquid waste or water is added. The High Performance In-Drum Mixer is a combination of planetary mixer with double helical mixer. NUKEM Technologies recently has developed a new High Capacity Mixer (HCM) based on a well proven conventional concrete mixer. The HCM is the successor of the slant mixer and will expend NUKEM Technologies' portfolio of cementation units. (A.C.)

  12. Barium aluminate cement: its application

    International Nuclear Information System (INIS)

    The technology of manufacturing barium aluminate cement from barium sulfate and alumina, using a rotary kiln for firing the clinker is described. The method of granulation of the homogenized charge was used. Conditions of using the ''to mud'' method in industry were indicated. The physical and chemical properties of barium aluminate cement are determined and the quality of several batches of cement prepared on a semi-industrial scale and their suitability for making highly refractory concretes are tested. The optimal composition of the concretes is determined as a function of the mixing water and barium aluminate cement contents. Several experimental batches of concretes were used in the linings of furnaces in the steel industry. The suitability of these cements for use in fields other than steelmaking is examined. It is established that calcium aluminate cement has certain limited applications

  13. [Haemotoxicity of dental luting cements].

    Science.gov (United States)

    Anders, A; Welker, D

    1989-06-01

    A glass ionomer luting cement (AquaCem) shows a relatively low haemolytic activity in comparison with two zinc phosphate cements. Especially the initial irritation by this cement is smaller. Although it is possible that AquaCem particularly, in unfavourable cases, may damage the pulpa dentin system; this is due to the slowly decrease of the haemolytic activity with increasing of the probes. We found that Adhesor showed in dependence of the batches a varying quality. PMID:2626769

  14. Cement penetration after patella venting.

    Science.gov (United States)

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement. PMID:19010682

  15. Cationic Liposome-Mediated CXCR4 Gene Delivery into Hematopoietic Stem/Progenitor Cells: Implications for Clinical Transplantation and Gene Therapy

    OpenAIRE

    Gul-Uludag, Hilal; Xu, Peng; Marquez-Curtis, Leah A.; Xing, James; Janowska-Wieczorek, Anna; Chen, Jie

    2011-01-01

    The chemokine stromal cell-derived factor (SDF)-1α/CXCL12 and its receptor CXC chemokine receptor 4 (CXCR4) play a crucial role in the homing/engraftment and retention of hematopoietic stem/progenitor cells (HSPCs) in the bone marrow. It has been shown using the viral gene transfer technique that CXCR4 overexpression on human CD34+ HSPC significantly improves their engraftment in murine models. However, clinical trials with gene therapy have revealed safety concerns related to the immunogenic...

  16. Chiaroscuro hematopoietic stem cell.

    OpenAIRE

    Quesenberry, P.; Habibian, M. (PhD); Dooner, M; Zhong, S.; Reilly, J; Peters, S.; De Becker, P; Grimaldi, C.; Carlson, J; REDDY, P; Nilsson, S.; Stewart, F. M.

    1998-01-01

    These observations suggest several immediate clinical strategies. In gene therapy, approaches could be targeted to obtain cycling of hematopoietic stem cells and gene-carrying retrovirus vector integration followed by engraftment at an appropriate time interval which favors engraftment. The same type of approach can be utilized for stem cell expansion approaches. Alternatively marrow or peripheral stem cell engraftment can be obtained with minimal to no toxicity in allochimeric strategies in ...

  17. Improvement of in vitro physicochemical properties and osteogenic activity of calcium sulfate cement for bone repair by dicalcium silicate

    International Nuclear Information System (INIS)

    Highlights: • Dicalcium silicate can improve osteogenic activity of calcium sulfate cement. • The higher the calcium sulfate content, the shorter the setting time in the composite cement. • The results were useful for designing calcium-based cement with optimal properties. -- Abstract: An ideal bone graft substitute should have the same speed of degradation as formation of new bone tissue. To improve the properties of calcium sulfate hemihydrate (CSH) featured for its rapid resorption, a low degradation material of dicalcium silicate (DCS) was added to the CSH cement. This study examined the effect of DCS (20, 40, 60 and 80 wt%) on the in vitro physicochemical properties and osteogenic activities of the calcium-based composite cements. The diametral tensile strength, porosity and weight loss of the composite cements were evaluated before and after soaking in a simulated body fluid (SBF). The osteogenic activities, such as proliferation, differentiation and mineralization, of human mesenchymal stem cells (hMSCs) seeded on cement surfaces were also examined. As a result, the greater the DCS amount, the higher the setting time was in the cement. Before soaking in SBF, the diametral tensile strength of the composite cements was decreased due to the introduction of DCS. On 180-day soaking, the composite cements containing 20, 40, 60 and 80 wt% DCS lost 80%, 69%, 61% and 44% in strength, respectively. Regarding in vitro bioactivity, the DCS-rich cements were covered with clusters of apatite spherulites after soaking for 7 days, while there was no formation of apatite spherulites on the CSH-rich cement surfaces. The presence of DCS could reduce the degradation of the CSH cements, as evidenced in the results of weight loss and porosity. More importantly, DCS may promote effectively the cell proliferation, proliferation and mineralization. The combination of osteogenesis of DCS and degradation of CSH made the calcium-based composite cements an attractive choice for

  18. Respiratory Health among Cement Workers in Ethiopia

    OpenAIRE

    Zeleke, Zeyede K.

    2011-01-01

    Background: Little is known on dust exposure and respiratory health among cement cleaners. There are only a few follow-up studies on respiratory health among cement factory workers and also studies on acute effects of cement dust exposure are limited in numbers. Objective: This study aimed at assessing cement dust exposure and adverse respiratory health effects among Ethiopian cement production workers, with particular focus on cement cleaners. Method: The first paper was...

  19. [Evaluation of the histocompatibility of endodontic cement in subcutaneous connective tissue using three methods].

    Science.gov (United States)

    Ferraz, S L; Birman, E G; Antoniazzi, J H; Magalhães, J

    1990-01-01

    It was employed three methods to evaluate the histocompatibility of a root canal filling cement, as the N-Rickert paste: implantation of round glass cover slips, polyethylene tubes and pellets of the cement. The results demonstrated qualitative and quantitative differences among the methods utilized indicating as a good toll the use of glass cover slips covered by the cement, since they provide good conditions of work, major areas of study, as also facilities in obtaining the specimens for study. The pellets didn't simulate the clinical conditions of the cement and the very small areas of study of the polyethylene tubes don't give definitive conclusions. PMID:2135431

  20. Thermal Shock-resistant Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  1. On the development of an apatitic calcium phosphate bone cement

    Indian Academy of Sciences (India)

    Manoj Komath; H K Varma; R Sivakumar

    2000-04-01

    Development of an apatitic calcium phosphate bone cement is reported. 100 Particles of tetracalcium phosphate (TTCP) and dicalcium phosphate dihydrate (DCPD) were mixed in equimolar ratio to form the cement powder. The wetting medium used was distilled water with Na2HPO4 as accelerator to manipulate the setting time. The cement powder, on wetting with the medium, formed a workable putty. The setting times of the putty were measured using a Vicat type apparatus and the compressive strength was determined with a Universal Testing Machine. The nature of the precipitated cement was analyzed through X-ray diffraction (XRD), fourier transform infrared spectrometry (FTIR) and energy dispersive electron microprobe (EDAX). The results showed the phase to be apatitic with a calcium–to–phosphorous ratio close to that of hydroxyapatite. The microstructure analysis using scanning electron microscopy (SEM) showed hydroxyapatite nanocrystallite growth over particulate matrix surface. The structure has an apparent porosity of ∼ 52%. There were no appreciable dimensional or thermal changes during setting. The cement passed the in vitro toxicological screening (cytotoxicity and haemolysis) tests. Optimization of the cement was done by manipulating the accelerator concentration so that the setting time, hardening time and the compressive strength had clinically relevant values.

  2. Health hazards of cement dust

    International Nuclear Information System (INIS)

    ven in the 21st century, millions of people are working daily in a dusty environment. They are exposed to different types of health hazards such as fume, gases and dust, which are risk factors in developing occupational disease. Cement industry is involved in the development of structure of this advanced and modern world but generates dust during its production. Cement dust causes lung function impairment, chronic obstructive lung disease, restrictive lung disease, pneumoconiosis and carcinoma of the lungs, stomach and colon. Other studies have shown that cement dust may enter into the systemic circulation and thereby reach the essentially all the organs of body and affects the different tissues including heart, liver, spleen, bone, muscles and hairs and ultimately affecting their micro-structure and physiological performance. Most of the studies have been previously attempted to evaluate the effects of cement dust exposure on the basis of spirometry or radiology, or both. However, collective effort describing the general effects of cement dust on different organ and systems in humans or animals, or both has not been published. Therefore, the aim of this review is to gather the potential toxic effects of cement dust and to minimize the health risks in cement mill workers by providing them with information regarding the hazards of cement dust. (author)

  3. A meta-analysis of efficacy in pre-clinical human stem cell therapies for traumatic brain injury

    OpenAIRE

    Chang, J.; Phelan, M; Cummings, BJ

    2015-01-01

    © 2015 Elsevier Inc. Objectives: Evaluate the preclinical evidence for human cell therapies for the treatment of traumatic brain injury (TBI), determine behavioral effect sizes for modified and non-modified cells, and identify variables that correlate with greater effect sizes. Methods: A literature search identified 58 animal studies of TBI using human stem cells. Each study received a Quality Index (QI) score based on existing guidelines. Effect sizes for cell therapies were determined for ...

  4. Colon Cancer Stem Cells: Bench-to-Bedside—New Therapeutical Approaches in Clinical Oncology for Disease Breakdown

    International Nuclear Information System (INIS)

    It is widely accepted by the scientific community that cancer, including colon cancer, is a “stem cell disease”. Until a few years ago, common opinion was that all neoplastic cells within a tumor contained tumorigenic growth capacity, but recent evidences hint to the possibility that such a feature is confined to a small subset of cancer-initiating cells, also called cancer stem cells (CSCs). Thus, malignant tumors are organized in a hierarchical fashion in which CSCs give rise to more differentiated tumor cells. CSCs possess high levels of ATP-binding cassette (ABC) transporters and anti-apoptotic molecules, active DNA-repair, slow replication capacities and they produce growth factors that confer refractoriness to antineoplastic treatments. The inefficacy of conventional therapies towards the stem cell population might explain cancer chemoresistance and the high frequency of relapse shown by the majority of tumors. Nowadays, in fact all the therapies available are not sufficient to cure patients with advanced forms of colon cancer since they target differentiated cancer cells which constitute most of the tumor mass and spare CSCs. Since CSCs are the entities responsible for the development of the tumor and represent the only cell population able to sustain tumor growth and progression, these cells represent the elective target for innovative therapies

  5. Migration and strains induced by different designs of force-closed stems for THA ☆

    OpenAIRE

    Sandro Griza; Luiz Sérgio Marcelino Gomes; André Cervieri; Telmo Roberto Strohaecker

    2015-01-01

    ABSTRACT Objectives: Subtle differences in stem design can result in different mechanical responses of the total hip arthroplasty. Tests measuring migration of the stem relative to the femur, as well as the strains in the cement mantle and on the femur can detect different mechanical behavior between stems. Methods: In this article, conical, double and triple tapered stems were implanted in composite femurs and subjected to static and cyclic loads. Stems differed mainly on taper angle, ca...

  6. The behavior of implant-supported dentures and abutments using the cemented cylinder technique with different resinous cements

    Directory of Open Access Journals (Sweden)

    Ivete Aparecida de Mathias Sartori

    2008-01-01

    Full Text Available Objective: Evaluate the behavior of implant-supported dentures and their components, made by cemented cylinder technique, using threetypes of resin cements. Methods: Fifty three patients, of whom 26 were women and 27 men, aged between 25 and 82 years. Results: With partial (54.43% and total (45.57% implant-supported dentures, of the Cone Morse, external and internal hexagon types (Neodent®, Curitiba, Brazil, totaling 237 fixations, were analyzed. The resin cements used were Panavia® (21.94%, EnForce® (58.23% and Rely X® (19.83% and the components were used in accordance with the Laboratory Immediate Loading - Neodent® sequence. The period of time of denture use ranged between 1 and 5 years. The results reported that 5(2.1% cylinders were loosened from metal structure (both belonging to Rely X group, 2(0.48% implants were lost after the first year of use, 16(6.75% denture retention screws wereloosened and 31(13.08% abutment screws were unloosened.Conclusion: The reasons for these failures probably are: metal structure internal retention failure, occlusal pattern, cementation technique and loading conditions. The cemented cylinder technique was effective when used in partial and total implant-supported rehabilitations, keeping prosthetic components stable, despite the resin cement utilized. However, further clinical studies must be conducted.

  7. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    A K Misra; Renu Mathur

    2007-06-01

    The scope of magnesium oxychloride (MOC) cement in concrete works has been evaluated. MOC cement concrete compositions of varying strengths having good placing and finishing characteristics were prepared and investigated for their compressive and flexural strengths, -values, abrasion resistance etc. The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ratio of compressive to flexural strength varies between 6 and 8. The elastic moduli of the compositions studied are found to be 23–85 GPa and the abrasion losses between 0.11 and 0.20%. While alternate heating–cooling cycles have no adverse effect on MOC concrete, it can be made durable against freezing–thawing and the excessive exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution of the same concentration.

  8. Progress in the clinical treatment based on breast cancer stem cells%基于乳腺癌干细胞的临床治疗进展

    Institute of Scientific and Technical Information of China (English)

    任远; 李泽桂

    2011-01-01

    and August 2010 were retrieved by the computer with the key words of "breast cancer, cancer stem cells, therapy" in English. Literatures were limited to English language. The literatures included clinical research, basic research, and reviews. A total of 204 literatu res were obtained from the computer screen,repetitive researches were excluded, and 33 documents of them were involved for further analysis.RESULTS AND CONCLUSION: Breast cancer stem cells are the first identified cancer stem cells in solid tumor. Breast cancer stem cells have been isolated successfully by many kinds of strategies, and biological characteristics are gradually studied deeply.Self-renewal and differentiation of breast cancer stem cells are regulated by microenvironment and many signaling pathways.Targeted therapy of breast cancer stem cells is gradually becoming the focus of tumor targeted therapy study.

  9. Analysis of stresses during the polymerization shrinkage of self-curing resin cement in indirect restorations: A finite-element study

    OpenAIRE

    Tulimar M Cornacchia; Guilherme C Silva; Claudia S Magalhaes; Moreira, Allyson N.; Estevam B Las Casas

    2014-01-01

    Background: Adhesive cementation is essential for the longevity of indirect esthetic restorations. However, polymerization shrinkage of resin cement generates stress, which may cause failures in the tooth-restoration interface. So, understanding of the biomechanics of resin cement is important for predicting the clinical behavior of an esthetic indirect restoration. Aims: To analyze the stresses generated during polymerization shrinkage of self-curing resin cement in ceramic and in indire...

  10. In vivo characterization of polymer based dental cements

    Directory of Open Access Journals (Sweden)

    Widiyanti P

    2011-12-01

    Full Text Available Background: In vivo studies investigating the characterization of dental cements have been demonstrated. As few in vitro studies on this cement system have been performed. Previous researches in dental material has been standardized dental cement which fulfilled the physical and mechanical characteristic such as shear strength but were on in vitro condition, the animal model and clinical study of dental cement from laboratory has not been done yet. This research examined physical and mechanical characteristic in vivo using rabbit by making the caries (class III in anterior teeth especially in mesial or distal incisive, fulfilled the cavity by dental cement and analyzed the compressive strength, tensile strength, and microstructure using scanning electron microscope (SEM. Purpose: This study is aimed to describe the in vivo characterization of dental cements based on polymer (zinc phosphate cement, polycarboxylate, glass ionomer cement and zinc oxide eugenol. Methods: First, preparation was done on animal model’s teeth (6 rabbits, male, 5 months old. The cavity was made which involved the dentin. Then the cavity was filled with dental cement. After the filling procedure, the animal model should be kept until 21 days and than the compressive test, tensile test and microstructure was characterized. Compressive test and tensile test was analyzed using samples from extracted tooth and was measured with autograph. The microstructure test was measured using SEM. Results: The best compressive strength value was belongs to zinc phosphate cement which was 101.888 Mpa and the best tensile strength value was belongs to glass ionomer cement which was 6.555 Mpa. Conclusion: In conclusion, comparing with 3 others type of dental cements which are zinc phosphate, polycarboxylate and glass ionomer cement, zinc oxide eugenol cement has the worst for both physical and mechanical properties.Latar belakang: Studi in vivo meneliti karakterisasi secara in vivo dari

  11. Cementation of Glass-Ceramic Posterior Restorations: A Systematic Review

    Science.gov (United States)

    van den Breemer, Carline R. G.; Gresnigt, Marco M. M.; Cune, Marco S.

    2015-01-01

    Aim. The aim of this comprehensive review is to systematically organize the current knowledge regarding the cementation of glass-ceramic materials and restorations, with an additional focus on the benefits of Immediate Dentin Sealing (IDS). Materials and Methods. An extensive literature search concerning the cementation of single-unit glass-ceramic posterior restorations was conducted in the databases of MEDLINE (Pubmed), CENTRAL (Cochrane Central Register of Controlled Trials), and EMBASE. To be considered for inclusion, in vitro and in vivo studies should compare different cementation regimes involving a “glass-ceramic/cement/human tooth” complex. Results and Conclusions. 88 studies were included in total. The in vitro data were organized according to the following topics: (micro)shear and (micro)tensile bond strength, fracture strength, and marginal gap and integrity. For in vivo studies survival and quality of survival were considered. In vitro studies showed that adhesive systems (3-step, etch-and-rinse) result in the best (micro)shear bond strength values compared to self-adhesive and self-etch systems when luting glass-ceramic substrates to human dentin. The highest fracture strength is obtained with adhesive cements in particular. No marked clinical preference for one specific procedure could be demonstrated on the basis of the reviewed literature. The possible merits of IDS are most convincingly illustrated by the favorable microtensile bond strengths. No clinical studies regarding IDS were found. PMID:26557651

  12. Antibacterial Activity of Dental Cements Containing Quaternary Ammonium Polyethylenimine Nanoparticles

    International Nuclear Information System (INIS)

    Glass ionomer cements (GICs) are commonly used for cementing full cast crown restorations. Regrettably, although the dental cements fill the gap between the tooth and the crown, bacterial micro leakage may occur, resulting in secondary caries. As micro leakage cannot be completely prevented, GCS possessing antibacterial properties are in demand. In the present study the antibacterial activity of insoluble, cross-linked quaternary ammonium polyethylenimine (Qp) nanoparticles incorporated at 1% w/w in two clinically available GCS were studied. The antibacterial activity was tested against Streptococcus mutans and Lactobacillus casei using the direct contact test (Dct) and the agar diffusion test (Ad). Using the direct contact test, antibacterial activity (P<0.05) was found in both tested GICs with incorporated QPEI nanoparticles, the effect lasting for at least one month. However, the ADT showed no inhibition halo in the test bacteria, indicating that the antimicrobial nanoparticles do not diffuse into the agar. The results show that the incorporation of QPEI nanoparticles in glass ionomer cements has a long-lasting antibacterial effect against Streptococcus mutans and Lactobacillus casei. Changing the antibacterial properties of glass ionomer cements by incorporating QPEI antibacterial nanoparticles may prolong the clinical performance of dental crowns.

  13. Stem cell therapy for diabetes

    OpenAIRE

    Lee, K. O.; Gan, S U; Calne, R Y

    2012-01-01

    Stem cell therapy holds immense promise for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced plu...

  14. Stem cell research in China

    OpenAIRE

    Liao, Lianming; Li, Lingsong; Zhao, Robert Chunhua

    2007-01-01

    In the past 5 years, China has increased its efforts in the field of stem cell research and practice. Basic research mainly focuses on bone marrow and embryonic stem cells. Clinical applications of stem cells in the treatment of acute heart failure, acute liver failure and lower limb ischaemia have been reported by many hospitals. China enacted its ‘Ethical Guidelines for Human Embryonic Stem Cell Research’ in 2003. At present, China has the most liberal and favourable environments for human ...

  15. Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells in leukapheresis product and bone marrow for clinical transplantation: a comparison of three methods.

    Directory of Open Access Journals (Sweden)

    E Kraszewska

    2006-04-01

    Full Text Available Flow cytometric enumeration of CD34+ hematopoietic stem and progenitor cells (HSCs is widely used for evaluation of graft adequacy of peripheral blood and bone marrow stem cell grafts. In the present study, we review and compare the major counting techniques of stem and progenitor cells. The methods are: the Milan/Mullhouse protocol, two-platform ISHAGE (International Society of Hematotherapy and Graft Engineering and single-platform ISHAGE analysis system. According to the Milan/Mulhouse protocol, HSCs are identified by CD34 antibody staining and easy gating strategy. The ISHAGE guidelines for detection of CD34+ cells are based on a four-parameter flow cytometry method (CD34PE/CD45PerCP staining, side and forward angle light scatter thus employing multiparameter gating strategy. With two-platform ISHAGE protocol, an absolute CD34+ count is generated by incorporating the leukocyte count from an automated hematology analyser. The single-platform ISHAGE method to determine the absolute CD34+ count directly from a flow cytometer includes the use of Trucount tubes (Becton Dickinson with a known number of fluorescent beads. CD34+ cells were quantified in mobilized peripheral blood, collected by leukapheresis, and bone marrow from 42 samples from patients with hematological malignancies. The differences against the means display low disagreement between the Milan/Mulhouse and ISHAGE protocols, with discrepancies of up to 2.5% (two-platform ISHAGE--2.6% (single-platform ISHAGE in enumeration of CD34+ cells in leukapheresis product and 4.8% (two-platform ISHAGE--4.9% (single-platform ISHAGE in bone marrow. Our results show high correlation among all three methods. Since the three protocols are compatible, choosing the most convenient in terms of costs, simplicity and compliance with clinical results appears to be a logical consequence.

  16. Intraoperative monitoring for safety of total hip arthroplasty using third-generation cementing technique

    Institute of Scientific and Technical Information of China (English)

    LI Zi-jian; ZHANG Ke; YANG Hong; LIU Yan; L(U) Jing-qiao

    2009-01-01

    Background Controversies on the safety of the cement application between cemented and uncemented total hip arthroplasty (THA) have been existing for decades. The purpose of this study was to observe the changes in mean arterial pressure (MAP), heart rate (HR) and oxygen pressure (PaO2) during cemented THA, and to evaluate the intraoperative safety of using the third-generation cementing technique and investigate whether the intraoperative risk is higher in acute femoral neck fracture patients than non-traumatic patients. Methods Forty-two patients who underwent cemented THA between November 2005 and September 2007 were prospectively included in this study. The third-generation cementing technique as vacuum mixing and pulsatile lavage was used strictly. The MAP and HR were monitored and documented during each operation. Blood gas analysis was performed at exposure, cup implantation, stem implantation and wound closure. MAP, HR and PaO2 were compared between pre- and post-cement application. Comparisons of MAP, HR and PaO2 between patients with acute femoral neck fracture and non-traumatic patiens were performed as well. Results No intraoperative cardiopulmonary complication occurred in these cases. No obvious changes were observed in MAP, HR and PaO2 after cement application. There was no significant difference in MAP, HR and PaO2 between acute femoral fracture patients (18 patients) and non-traumatic patients (24 patients).Conclusions The results of this study suggested that the invasive blood pressure monitoring and blood gas analysis are essential for patients undergoing cemented THA, especially for patients with femoral neck fracture. The third-generation cementing technique is safe to use in THA.

  17. Cements in Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    The use of cement and concrete to immobilise radioactive waste is complicated by the wide- ranging nature of inorganic cementing agents available as well as the range of service environments in which cement is used and the different functions expected of cement. For example, Portland cement based concretes are widely used as structural materials for construction of vaults and tunnels. These constructions may experience a long pre-closure performance lifetime during which they are required to protect against collapse and ingress of water: strength and impermeability are key desirable characteristics. On the other hand, cement and concrete may be used to form backfills, ranging in permeability. Permeable formulations allow gas readily to escape, while impermeable barriers retard radionuclide transport and reduce access of ground water to the waste. A key feature of cements is that, while fresh, they pass through a fluid phase and can be formed into any shape desired or used to infiltrate other materials thereby enclosing them into a sealed matrix. Thereafter, setting and hardening is automatic and irreversible. Where concrete is used to form structural elements, it is also natural to use cement in other applications as it minimises potential for materials incompatibility. Thus cement- mainly Portland cement- has been widely used as an encapsulant for storage, transport and as a radiation shield for active wastes. Also, to form and stabilise structures such as vaults and silos. Relative to other potential matrices, cement also has a chemical immobilisation potential, reacting with and binding with many radionuclides. The chemical potential of cements is essentially sacrificial, thus limiting their performance lifetime. However performance may also be required in the civil engineering sense, where strength is important, so many factors, including a geochemical description of service conditions, may require to be assessed in order to predict performance lifetime. The

  18. Cement/slag chemistry studies

    International Nuclear Information System (INIS)

    The performance of cement-based matrices intended for radwaste immobilization is assessed. The long-term performance of the matrix is characterized by thermodynamic evaluation of experimental data. The results are presented in a general form, amenable to a range of specific formulations. The interaction of specific radwaste components with cements has been studied, using Iodine as an example. It occurs as both I- and IO3- species, but these differ sharply in sorption characteristics. The effect of ionizing radiation of the pH and Eh of cement matrices is reported. (author)

  19. Physical characteristics, antimicrobial and odontogenesis potentials of calcium silicate cement containing hinokitiol.

    Science.gov (United States)

    Huang, Ming-Hsien; Shen, Yu-Fang; Hsu, Tuan-Ti; Huang, Tsui-Hsien; Shie, Ming-You

    2016-08-01

    Hinokitiol is a natural material and it has antibacterial and anti-inflammatory effects. The purpose of this study was to evaluate the material characterization, cell viability, antibacterial and anti-inflammatory abilities of the hinokitiol-modified calcium silicate (CS) cement as a root end filling material. The setting times, diametral tensile strength (DTS) values and XRD patterns of CS cements with 0-10mM hinokitiol were examined. Then, the antibacterial effect and the expression levels of cyclooxygenase 2 (COX-2) and interleukin-1 (IL-1) of the hinokitiol-modified CS cements were evaluated. Furthermore, the cytocompatibility, the expression levels of the markers of odontoblastic differentiation, mineralized nodule formation and calcium deposition of human dental pulp cells (hDPCs) cultured on hinokitiol-modified CS cements were determined. The hinokitiol-modified CS cements had better antibacterial and anti-inflammatory abilities and cytocompatibility than non-modified CS cements. Otherwise, the hinokitiol-modified CS cements had suitable setting times and better odontoblastic potential of hDPCs. Previous report pointed out that the root-end filling materials may induce inflammatory cytokines reaction. In our study, hinokitiol-modified CS cements not only inhibited the expression level of inflammatory cytokines, but also had better cytocompatibility, antimicrobial properties and active ability of odontoblastic differentiation of hDPCs. Therefore, the hinokitiol-modified CS cement may be a potential root end filling material for clinic. PMID:27157721

  20. Preliminary experimental results of radiofrequency-cement-augmented and cannulated pedicle screws

    Directory of Open Access Journals (Sweden)

    Goost H

    2011-01-01

    Full Text Available The risk of cut-out of a pedicle screw is high in the presence of osteoporotic bone. In cadaver studies it was found that cement augmentation of pedicle screws markedly increases pullout forces. However, the use of conventional low viscosity vertebroplasty or kyphoplasty cement is associated with the risk of cement extravasation. The risk might be reduced by using high viscosity, radiofrequency-activated bone cement. After performing DEXA scans, six fresh-frozen vertebral bodies of different bone densities were obtained from cadavers. Two pedicle screws (WSI Expertise-Inject, Peter Brehm, Germany were placed in the pedicles. About 3 ml of radiofrequency-activated, ultra-high viscosity cement (ER2 Bone Cement, DFine Europe GmbH, Germany was injected through the right pedicle. The left pedicle screw was left uncemented and served as control. Axial pullout tests were performed using a material testing device (Zwick/Roell Zmartpro, Ulm, Germany. The tests revealed that cementaugmented pedicle screws were able to withstand markedly higher pullout forces. Extravasation of cement did not occur. The value of the study is limited by the fact that only six samples were investigated. Further cadaver studies and clinical evaluation will be needed in the future. However, this pilot study showed that combining cannulated pedicle screws with ultra-high viscosity bone cement is a successful approach. Revision due to cut-out and complications secondary to cement extravasation can be reduced by this method.

  1. Autologous Bone Marrow Stem Cells in Spinal Cord Injury; Our Experience in Clinical Studies, Animal Studies, Obstacles faced and steps for future

    Directory of Open Access Journals (Sweden)

    Ayyappan S

    2010-01-01

    , Santos M. Cell therapy using bone marrow stromal cells in chronic paraplegic rats: systemic or local administration? Neurosci Lett. 2006 May.3.de Haro J, Zurita M, Ayllón L, Vaquero J. Detection of 111.In-oxine-labeled bone marrow stromal cells after intravenous or intralesional administration inchronic paraplegic rats. Neurosci Lett. 2005 Mar4.Yano S, Kuroda S, Lee JB, Shichinohe H, Seki T, Ikeda J, Nishimura G, Hida K, Tamura M, Iwasaki Y. In vivo fluorescence tracking of bone marrow stromal cells transplanted into pneumatic injury model of rat spinal cord. J Neurotrauma.2005 Aug5.Ravikumar R, Narayanan S, Baskar S, SenthilNagarajan R, Abraham S. Autologous Stem Cell Injection for Spinal Cord Injury- A Clinical Study from India. PASRM 2007-0046.Justin William B, Ayyappan S, DhanaJayaRao G, Pushkinraj H, Kannan TA , Sureshkumar R, Manjunath S, Murugan P, Srinivasan V, Abraham S. Intralesional Application of Autologous Bone Marrow Stem Cells with Scaffold in Canine for Spinal Cord Injury. PASRM, IV annual symposium , 2009.7.Yasuda H, Kuroda S, Shichinohe H, Kamei S, Kawamura R, Iwasaki Y. Effect of biodegradable fibrin scaffold on survival, migration, and differentiation of transplanted bone marrow stromal cells after cortical injury in rats. J Neurosurg. 2010 ;112(2:336-44. 8.Abraham et al. Stem cell Clinical trials Session. Stem cell Global blue Print Conference (21-22 May2010 Toronto, Canada

  2. Stem cells and respiratory diseases

    OpenAIRE

    Soraia Carvalho Abreu; Tatiana Maron-Gutierrez; Cristiane Sousa Nascimento Baez Garcia; Marcelo Marcos Morales; Patricia Rieken Macedo Rocco

    2008-01-01

    Stem cells have a multitude of clinical implications in the lung. This article is a critical review that includes clinical and experimental studies of MedLine and SciElo database in the last 10 years, where we highlight the effects of stem cell therapy in acute respiratory distress syndrome or more chronic disorders such as lung fibrosis and emphysema. Although, many studies have shown the beneficial effects of stem cells in lung development, repair and remodeling; some important questions ne...

  3. (α'(H))-Dicalcium silicate bone cement doped with tricalcium phosphate: characterization, bioactivity and biocompatibility.

    Science.gov (United States)

    de Aza, Piedad N; Zuleta, Fausto; Velasquez, Pablo; Vicente-Salar, Nestor; Reig, Juan A

    2014-02-01

    The influence of phosphorus doping on the properties of (α'(H))-dicalcium silicate (C(2)S) bone cement was analyzed, in addition to bioactivity and biocompatibility. All the cements were composed of a solid solution of TCP in C(2)S ([Formula: see text]-C(2)S(ss)) as the only phase present. The compressive strength ranged from 3.8-16.3 MPa. Final setting times ranged from 10 to 50 min and were lower for cements with lower L/P content. Calcium silicate hydrate was the principal phase formed during the hydration process of the cements. The cement exhibited a moderate degradation and could induce carbonated hydroxyapatite formation on its surface and into the pores. The cell attachment test showed that the (α'(H))-C(2)SiO(4) solid solution supported human adipose stem cells adhesion and spreading, and the cells established close contacts with the cement after 24 h of culture. The novel (α'(H))-C(2)S(ss) cements might be suitable for potential applications in the biomedical field, preferentially as materials for bone/dental repair. PMID:24218299

  4. Evaluation of oxidative stress and DNA damage in cement and tannery workers in Egypt.

    Science.gov (United States)

    Elhosary, Naema; Maklad, Aisha; Soliman, Eman; El-Ashmawy, Nahla; Oreby, Merfat

    2014-04-01

    In Egypt, workers have potentially high exposure levels to chromium (VI) in the cement production and construction industry and to chromium (III) in the leather tanning industry. This study aimed to evaluate the effect of chromium exposure on lipoperoxidation, thiol antioxidants and DNA in cement and tannery workers. This study was conducted on 65 adult male volunteers. These subjects were divided into three groups: Group I (control group); 23 normal healthy volunteers, Group II; 22 cement workers and Group III; 20 tannery workers. All participants were subjected to thorough history, clinical examination and laboratory determination of total blood and urinary chromium, plasma malondialdehyde and total thiol in plasma and assessment of oxidative DNA damage through p53 overexpression. About one third of cement and tannery workers had severe skin and chest manifestations and severe nasal manifestations were observed in 22.7% and 20% of cement and tannery workers, respectively. The blood and urinary Cr and plasma malondialdehyde levels of cement and tannery were significantly higher than control group. Additionally, there was a significant increase of total thiol in control group compared to exposed groups. About half of cement and one third of tannery groups expressed high grade of p53 expression. The blood chromium revealed significant negative correlation with thiol, but, positive correlation with malondialdehyde and p53 expression. Cement and tannery workers should be subjected to frequent clinical examination and blood or urine chromium analysis level to keep guard against its toxic consequences. PMID:24617565

  5. Pulmonary cement embolism after pedicle screw vertebral stabilization

    Directory of Open Access Journals (Sweden)

    Massimo Tonolini

    2012-01-01

    Full Text Available Pulmonary arterial embolization of polymethylmethacrylate cement, most usually occurring after vertebroplasty or kyphoplasty, is very uncommon following vertebral stabilization procedures. Unenhanced CT scans viewed at lung window settings allow confident identification of cement emboli in the pulmonary circulation along with possible associate parenchymal changes, whereas hyperdense emboli may be less conspicuous on CT-angiographic studies with high-flow contrast medium injection. Although clinical manifestations are largely variable from asymptomatic cases to severe respiratory distress, most cases are treated with anticoagulation.

  6. Sliding wear of cemented carbides

    International Nuclear Information System (INIS)

    Cemented carbides are known to be very hard and wear resistant and are therefor often used in applications involving surface damage and wear. The wear rate of cemented carbides is often measured in abrasion. In such tests it has been shown that the wear rate is inversely dependent on the material hardness. The sliding wear is even more of a surface phenomenon than a abrasion, making it difficult to predict friction and wear from bulk properties. This paper concentrates on the sliding wear of cemented carbides and elucidates some wear mechanisms. It is especially shown that a fragmenting wear mechanism of WC is very important for the description of wear of cemented carbides. (author)

  7. Alternative Fuels in Cement Production

    DEFF Research Database (Denmark)

    Larsen, Morten Boberg

    The substitution of alternative for fossil fuels in cement production has increased significantly in the last decade. Of these new alternative fuels, solid state fuels presently account for the largest part, and in particular, meat and bone meal, plastics and tyre derived fuels (TDF) accounted for...... the most significant alternative fuel energy contributors in the German cement industry. Solid alternative fuels are typically high in volatile content and they may differ significantly in physical and chemical properties compared to traditional solid fossil fuels. From the process point of view......, considering a modern kiln system for cement production, the use of alternative fuels mainly influences 1) kiln process stability (may accelerate build up of blockages preventing gas and/or solids flow), 2) cement clinker quality, 3) emissions, and 4) decreased production capacity. Kiln process stability in...

  8. Calcium Aluminate Cement Hydration Model

    Directory of Open Access Journals (Sweden)

    Matusinović, T.

    2011-01-01

    Full Text Available Calcium aluminate cement (AC is a very versatile special cement used for specific applications. As the hydration of AC is highly temperature dependent, yielding structurally different hydration products that continuously alter material properties, a good knowledge of thermal properties at early stages of hydration is essential. The kinetics of AC hydration is a complex process and the use of single mechanisms models cannot describe the rate of hydration during the whole stage.This paper examines the influence of temperature (ϑ=5–20 °C and water-to-cement mass ratio (mH /mAC = 0.4; 0.5 and 1.0 on hydration of commercial iron-rich AC ISTRA 40 (producer: Istra Cement, Pula, Croatia, which is a part of CALUCEM group, Figs 1–3. The flow rate of heat generation of cement pastes as a result of the hydration reactions was measured with differential microcalorimeter. Chemically bonded water in the hydrated cement samples was determined by thermo-gravimetry.Far less heat is liberated when cement and water come in contact for the first time, Fig. 1, than in the case for portland cement (PC. Higher water-to-cement ratio increases the heat evolved at later ages (Fig. 3 due to higher quantity of water available for hydration. A significant effect of the water-to-cement ratio on the hydration rate and hydration degree showed the importance of water as being the limiting reactant that slows down the reaction early. A simplified stoichiometric model of early age AC hydration (eq. (8 based on reaction schemes of principal minerals, nominally CA, C12A7 and C4AF (Table 1, was employed. Hydration kinetics after the induction period (ϑ < 20 °C had been successfully described (Fig. 4 and Table 2 by a proposed model (eq. (23 which simultaneously comprised three main mechanisms: nucleation and growth, interaction at phase boundary, and mass transfer. In the proposed kinetic model the nucleation and growth is proportional to the amount of reacted minerals (eq

  9. Mesenchymal stem cells.

    Science.gov (United States)

    Ding, Dah-Ching; Shyu, Woei-Cherng; Lin, Shinn-Zong

    2011-01-01

    Stem cells have two features: the ability to differentiate along different lineages and the ability of self-renewal. Two major types of stem cells have been described, namely, embryonic stem cells and adult stem cells. Embryonic stem cells (ESC) are obtained from the inner cell mass of the blastocyst and are associated with tumorigenesis, and the use of human ESCs involves ethical and legal considerations. The use of adult mesenchymal stem cells is less problematic with regard to these issues. Mesenchymal stem cells (MSCs) are stromal cells that have the ability to self-renew and also exhibit multilineage differentiation. MSCs can be isolated from a variety of tissues, such as umbilical cord, endometrial polyps, menses blood, bone marrow, adipose tissue, etc. This is because the ease of harvest and quantity obtained make these sources most practical for experimental and possible clinical applications. Recently, MSCs have been found in new sources, such as menstrual blood and endometrium. There are likely more sources of MSCs waiting to be discovered, and MSCs may be a good candidate for future experimental or clinical applications. One of the major challenges is to elucidate the mechanisms of differentiation, mobilization, and homing of MSCs, which are highly complex. The multipotent properties of MSCs make them an attractive choice for possible development of clinical applications. Future studies should explore the role of MSCs in differentiation, transplantation, and immune response in various diseases. PMID:21396235

  10. Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

    OpenAIRE

    Adriana Eštoková; Lenka Palaščáková

    2013-01-01

    The radionuclide activities of 226Ra, 232Th and 40K and radiological parameters (radium equivalent activity, gamma and alpha indices, the absorbed gamma dose rate and external and internal hazard indices) of cements and cement composites commonly used in the Slovak Republic have been studied in this paper. The cement samples of 8 types of cements from Slovak cement plants and five types of composites made from cement type CEM I were analyzed in the experiment. The radionuclide activities in t...

  11. Assessment of the compatibility of wood and plastic with cement for their recycling in cement composites

    OpenAIRE

    Andrade, André De; Caldeira, Fernando

    2010-01-01

    The compatibility between maritime pine wood and cement, and between plastic (LDPE) and cement, was assessed for the recycling of wood and plastic in cement composites. Temperature vs. time profiles of cement setting were registered and compatibility indices were calculated. Results indicate that recycling of plastics in plastic-cement composites does not pose any questions regarding chemical compatibility. However, maritime pine hinders cement setting in some extent. So, in or...

  12. Does Vertebroplasty Affect Radiation Dose Distribution?: Comparison of Spatial Dose Distributions in a Cement-Injected Vertebra as Calculated by Treatment Planning System and Actual Spatial Dose Distribution

    Directory of Open Access Journals (Sweden)

    Atsushi Komemushi

    2012-01-01

    Full Text Available Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution.

  13. Does Vertebroplasty Affect Radiation Dose Distribution?: Comparison of Spatial Dose Distributions in a Cement-Injected Vertebra as Calculated by Treatment Planning System and Actual Spatial Dose Distribution

    International Nuclear Information System (INIS)

    Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution

  14. In vitro evaluation of microleakage of various types of dental cements

    Directory of Open Access Journals (Sweden)

    Medić Vesna

    2010-01-01

    Full Text Available Introduction. Microleakage is defined as the clinically undetectable seepage of oral fluids containing bacteria and debris between cement layer and tooth restoration. Objective. This in vitro study investigated the effect of different dental cements (zinc-phosphate, polycarboxylate, glass-ionomer and resin cement on microleakage in different ceramic crown systems (metal ceramic crown, metal ceramic crown with a porcelain margin, Empress 2 and In Ceram all-ceramic crowns fixed on extracted human teeth. Methods. One hundred and sixty intact human premolars were randomized to four groups of forty teeth each, according to the different ceramic crown systems. They were prepared in a standardized manner for metal-ceramic and all-ceramic crowns. Crowns were made following a standard laboratory technique, and each group of crowns were divided into four groups according to the different cement agents and cemented on their respective abutments. The specimens were subjected to thermocycling, placed in methylene blue solutions, embedded in resin blocks and vertically cut in the bucco-oral and meso-distal direction. The microleakage in the area of tooth-cement interface was defined as linear penetration of methylene blue and was determined with a microscope to assign microleakage scores using a five-point scale. Results. A significant association was found between a cement type and degree of microleakage (p=0.001. No statistically significant differences were found among the different ceramic crown systems luted with the same dental cement. The smallest degree of microleakage was observed in specimens luted with resin cement (X=1.73, followed by glass-ionomer cement (X=2.45 and polycarboxylate cement (X=3.20. The greatest degree of microleakage was detected in the crowns fixed with zincphosphate cement (X=3.33. Conclusion. The investigated dental cements revealed different sealing abilities. The use of resin cement resulted in the percentage of 0

  15. Regulatory perspective on characterization and testing of orthopedic bone cements.

    Science.gov (United States)

    Demian, H W; McDermott, K

    1998-09-01

    This paper provides a general regulatory background of acrylic bone cements, chemical composition information on several commercially available bone cements, physical and chemical methods of analyses, mechanical test methods, and risks and failure mechanisms of acrylic bone cements. Suggestions and recommendations presented in Tables 2 and 3 are not mandatory requirements but reflect data and methodologies which the FDA's Orthopedic Devices Branch (ORDB) believes to be acceptable to evaluate most pre-clinical data. FDA may require information in addition to that contained in this paper. In some instances, a sponsor may be able to sufficiently justify the omission of some tests. Although this paper describes certain administrative requirements, it does not take the place of the requirements contained in Title 21 of the Code of Federal Regulations (21 CFR) Parts 801, 807, 812, and 814 or those found in the statute. PMID:9830987

  16. Surgical Results of Lumbar Interbody Fusion Using Calcium Phosphate Cement

    OpenAIRE

    HIRASAWA, Motohiro; Mure, Hideo; Toi, Hiroyuki; Nagahiro, Shinji

    2014-01-01

    Clinical and radiological outcomes of lumbar interbody fusion using artificial fusion cages filled with calcium phosphate cements (CPCs) were retrospectively reviewed. Between 2002 and 2011, 25 patients underwent lumbar interbody fusion at Tokushima University Hospital, and 22 patients were enrolled in this study. Of these, 5 patients received autologous local bone grafts and 17 received CPC. Japan Orthopedic Association (JOA) score was used for clinical outcome assessments. Lumbar radiograph...

  17. Indirect pulp capping in primary molar using glass ionomer cements

    OpenAIRE

    Murtia Metalita; Udijanto Tedjosasongko; Prawati Nuraini

    2014-01-01

    Background: Indirect pulp capping in primary teeth, however, is more rarely conducted than permanent teeth, since it thought to have low impact and most suggestion is for taking caries lesion aggressively on primary teeth. Purpose: The study was aimed to evaluate the subjective complaint, clinical symptom, and radiographic appearance of indirect pulp capping treatment using glass ionomers cements in primary molar. Methods: Sixteen children in range of age 6 to 8 years old, who visited Clinic ...

  18. Pooled human platelet lysate versus fetal bovine serum—investigating the proliferation rate, chromosome stability and angiogenic potential of human adipose tissue-derived stem cells intended for clinical use

    DEFF Research Database (Denmark)

    Trojahn Kølle, Stig-Frederik; Oliveri, Roberto S; Glovinski, Peter V; Kirchhoff, Eva Maria; Mathiasen, Anders Bruun; Elberg, Jens Jørgen; Andersen, Peter Stemann; Drzewiecki, Krzysztof Tadeusz; Fischer-Nielsen, Anne

    2013-01-01

    Because of an increasing focus on the use of adipose-derived stem cells (ASCs) in clinical trials, the culture conditions for these cells are being optimized. We compared the proliferation rates and chromosomal stability of ASCs that had been cultured in Dulbecco's modified Eagle's Medium (DMEM) ...

  19. Influence of Cements for Bonding Fiber Posts and Clinical Experience of Dentists on the Coronal Microleakage of Post-core Restoration%不同粘结系统及操作者临床经验及对纤维桩冠方微渗漏的影响

    Institute of Scientific and Technical Information of China (English)

    张志闻; 何海波; 杭东跃

    2013-01-01

    Objective :To evaluate Influence of cements for bonding fiber posts and clinical experience of dentists on the coronal microleakage of post-core restoration .Methods :Selected 60 teeth were randomly divided into three groups ac-cording to the kind of cements .Each of the group was randomly divided into two subgroups according to the clinical ex-perience of dentists ,expert and resident doctor .Bongding the posts to prepared root canals and reconstruct cores .The specimens were immersed in distilled water for one month .After dye and transparent .Each tooth was observed under stereoscopic microscope and the dyeing scores were recorded .Results:The microleakage degrees among three resin bonding cements were significantly different ,and group Paracore 5ml showed the least microleakage compared with oth-er three cements .Group RelyX Unicem showed the biggest microleakage .Conclusion:Dinfferent kinds of resin bonding cement have different degrees of the cronal microleakage of post-core restoratios .When the instructions for use of the resin cements were followed strictly ,the microleakage degrees were not affected by the clinical experience of dentists .%目的:为了评价不同粘结系统及操作者临床经验及对纤维桩冠方微渗漏的影响。方法:60颗人上颌前牙经过根管预备处理后根据使用的粘结系统随机分为3组,RelyX Unicem组,Clearfil DC Core Automix 组,Paracore 5ml组,分别为每组20个样本。以上3组每组再根据粘结操作者的临床经验随机分为两个亚组,一组为专家组,一组为医师组。将纤维桩粘结至根管并制作树脂核后,将样本置入37℃水中存储1个月。经染色及透明化处理。在体式显微镜下记录各亚组的微渗漏得分。结果:RelyX Unicem组纤维桩冠方微渗漏最严重。Paracore 5ml组纤维桩冠方微渗漏最轻。Clearfil DC Core Automix组微渗漏程度位于两者之间。纤维桩的粘结后的微渗漏情况不受临床

  20. Manufacture and properties of fluoride cement

    Science.gov (United States)

    Malata-Chirwa, Charles David

    This research work aimed at characterising composition, hydration and physical properties of fluoride cement, by studying samples of the cement obtained from Malawi, and comparing them to ordinary Portland cement. By confirming the suitable characteristics of fluoride cement through this work, the results of the research work provide a good basis for the wider adoption of fluoride cement as an alternative to ordinary Portland cement, especially in developing economies. Numerous accounts have been cited regarding the production and use of fluoride cement. Since there have not been conclusive agreement as to its properties, this study was limited to the theories of successful incorporation of fluoride compounds in the manufacture of fluoride cement. Hence, the properties and characteristics reported in this study relate to the cement currently manufactured in Malawi, and, on a comparative basis only, to that manufactured in other parts of the world. Samples of the fluoride cement used in the study were obtained by synthetic manufacture of the cement using common raw materials for the manufacture of fluoride cement that is limestone, silica sand, and fluorspar. These samples were subjected to several comparative tests used to characterise cements including examination under x-ray diffractometer, scanning electron microscopy and tests for setting time and compressive strength. Under similar laboratory conditions, it was possible to prove that fluoride cement hardens more rapidly than ordinary Portland cement. Also observed during the experimental work is that fluoride cement develops higher compressive strengths than ordinary Portland cement. The hardening and setting times are significantly different between the two cements. Also the nature of the hydration products, that is the microstructural development is significantly different in the two cements. The differences brought about between the two cements are because of the presence of fluorine during the clinkering

  1. Stem cell therapy for diabetes

    Directory of Open Access Journals (Sweden)

    K O Lee

    2012-01-01

    Full Text Available Stem cell therapy holds immense promise for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced pluripotent stem cells, umbilical cord stem cells and bone marrow-derived mesenchymal stem cells, have become an area of intense study. Recent advances in stem cell therapy may turn this into a realistic treatment for diabetes in the near future.

  2. Anterior spinal column augmentation with injectable bone cements.

    Science.gov (United States)

    Verlaan, Jorrit-Jan; Oner, F Cumhur; Dhert, Wouter J A

    2006-01-01

    A vertebral fracture, whether originating from osteoporosis or trauma, can be the cause of pain, disability, deformation and neurological deficit. The treatment of vertebral compression fractures has, for many years until the advent of vertebroplasty, consisted of bedrest and analgesics. Vertebroplasty is a percutaneous technique during which bone cement is injected in a vertebral body to provide immediate pain relief by stabilization. Inflatable bone tamps can, prior to the injection of cement, be used to create a void in the vertebral body, in which case the technique is known as balloon vertebroplasty (or kyphoplasty). The chance of extracorporal cement leakage is smaller for balloon vertebroplasty than for vertebroplasty. Some authors also claim to have gained some correction in vertebral body height or angulation. Both interventions can be used for several indications, including osteoporotic compression fractures and osteolytic lesions of the vertebral body such as myeloma, hemangioma or metastasis, and also for traumatic burst fractures in combination with pedicle screw instrumentation. Polymethyl methacrylate cement is the bone void filler that is used most frequently, although the application of calcium phosphate cements has been studied widely in vitro, in vivo and also in small-scale clinical series. The clinical results of (balloon-) vertebroplasty are favorable with 85-95% of all patients experiencing immediate and long-lasting relief of pain. Serious complications are relatively rare but include neurological deficit and pulmonary embolism. In this paper, both vertebroplasty and balloon vertebroplasty and their respective indications, techniques and results are described in relation with the application and limitations of permanent and resorbable injectable bone cements. PMID:16102818

  3. Large-Scale Clinical Expansion of Mesenchymal Stem Cells in the GMP-Compliant, Closed Automated Quantum® Cell Expansion System: Comparison with Expansion in Traditional T-Flasks

    OpenAIRE

    LECHANTEUR, Chantal; Baila, Stefano; Janssen, Michel Etienne; GIET, Olivier; Briquet, Alexandra; Baudoux, Etienne; Beguin, Yves

    2014-01-01

    Objectives: Significant advances have been achieved regarding the knowledge of the immunoregulatory properties of mesenchymal stem cells (MSC). We are currently involved in several clinical protocols evaluating these properties in different settings including hematopoietic cells or solid organ transplantation, and severe or refractory autoimmune disorders. Considering the large number of ex-vivo expanded cells required for these clinical protocols (MSC dose varies from 1 to 4x10-6 MSC/kg pati...

  4. Cement leakage in pedicle screw augmentation: a prospective analysis of 98 patients and 474 augmented pedicle screws.

    Science.gov (United States)

    Mueller, Jan U; Baldauf, Joerg; Marx, Sascha; Kirsch, Michael; Schroeder, Henry W S; Pillich, Dirk T

    2016-07-01

    OBJECTIVE Loosening and pullout of pedicle screws are well-known problems in pedicle screw fixation surgery. Augmentation of pedicle screws with bone cement, first described as early as 1975, increases the pedicle-screw interface and pullout force in osteoporotic vertebrae. The aim of the present study was to identify cement leakage and pulmonary embolism rates in a large prospective single-center series of pedicle screw augmentations. METHODS All patients who underwent cement-augmented pedicle screw placement between May 2006 and October 2010 at the authors' institution were included in this prospective cohort study. Perivertebral cement leakage and pulmonary cement embolism were evaluated with a CT scan of the area of operation and with a radiograph of the chest, respectively. RESULTS A total of 98 patients underwent placement of cement-augmented pedicle screws; 474 augmented screws were inserted in 237 vertebrae. No symptomatic perivertebral cement leakage or symptomatic pulmonary cement embolism was observed, but asymptomatic perivertebral cement leakage was seen in 88 patients (93.6%) and in 165 augmented vertebrae (73.3%). Cement leakage most often occurred in the perivertebral venous system. Clinically asymptomatic pulmonary cement embolism was found in 4 patients (4.1%). CONCLUSIONS Perivertebral cement leakage often occurs in pedicle screw augmentation, but in most cases, it is clinically asymptomatic. Cement augmentation should be performed under continuous fluoroscopy to avoid high-volume leakage. Alternative strategies, such as use of expandable screws, should be examined in more detail for patients at high risk of screw loosening. PMID:26943258

  5. The effect of cement creep and cement fatigue damage on the micromechanics of the cement-bone interface.

    Science.gov (United States)

    Waanders, Daan; Janssen, Dennis; Mann, Kenneth A; Verdonschot, Nico

    2010-11-16

    The cement-bone interface provides fixation for the cement mantle within the bone. The cement-bone interface is affected by fatigue loading in terms of fatigue damage or microcracks and creep, both mostly in the cement. This study investigates how fatigue damage and cement creep separately affect the mechanical response of the cement-bone interface at various load levels in terms of plastic displacement and crack formation. Two FEA models were created, which were based on micro-computed tomography data of two physical cement-bone interface specimens. These models were subjected to tensile fatigue loads with four different magnitudes. Three deformation modes of the cement were considered: 'only creep', 'only damage' or 'creep and damage'. The interfacial plastic deformation, the crack reduction as a result of creep and the interfacial stresses in the bone were monitored. The results demonstrate that, although some models failed early, the majority of plastic displacement was caused by fatigue damage, rather than cement creep. However, cement creep does decrease the crack formation in the cement up to 20%. Finally, while cement creep hardly influences the stress levels in the bone, fatigue damage of the cement considerably increases the stress levels in the bone. We conclude that at low load levels the plastic displacement is mainly caused by creep. At moderate to high load levels, however, the plastic displacement is dominated by fatigue damage and is hardly affected by creep, although creep reduced the number of cracks in moderate to high load region. PMID:20692663

  6. [Clinical efficacy of autologous mesenclyme multipotential stem cells transplantation in the liver cirrhosis and portal hypertension treatment].

    Science.gov (United States)

    2014-09-01

    In 14 patients with cirrhosis and portal hypertention autologous mesenclyme multipotential stem cells (AMMSC) transplanation was performed in portal vein (I group, n=7) and common trunk of the hepatic artery (II group, n=6). Duration of pathological processes since diagnosis is 1-8 years (3,7±2,4 years). The initial severity was evaluated by a set of child-Pugh score: Class A - 6 (42,9%), Class B - 8 (57,1%). Cell cultures indentication and characteristics consistent with International Society of cell technology guidanes (ISCT) since 2006.   The treatment results and patients survival were determined in period 2 month - 5 years according Kaplan-Meir survival curve analysis. Morphology of liver bioptats also was performed.   It was shown that AMMSC transplantation generally positivly affects on the morpho-functional dynamics and basic hepatic syndromes. Aterial perivascular zone is the most optimal for transplantation in terms of migration, engraftment and differentiation of cells in comparison with portal field, as evidenced by the transition of some patients from class B to class A by child-Pugh score. PMID:25341236

  7. Cementation of Loose Sand Particles based on Bio-cement

    Institute of Scientific and Technical Information of China (English)

    RONG Hui; QIAN Chunxiang

    2014-01-01

    Loose sand particles could be cemented to sandstone by bio-cement (microbial induced magnesium carbonate). The bio-sandstone was firstly prepared, and then the compressive strength and the porosity of the sandstone cemented by microbial induced magnesium carbonate were tested to characterize the cementation effectiveness. In addition, the formed mineral composition and the microstructure of bio-sandstone were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The experimental results show that the feasibility of binding loose sand particles using microbial induced magnesium carbonate precipitation is available and the acquired compressive strength of bio-sandstone can be excellent at certain ages. Moreover, the compressive strength and the porosity could be improved with the increase of microbial induced magnesium carbonate content. XRD results indicate that the morphology of magnesium carbonate induced by microbe appears as needles and SEM results show that the cementation of loose sand particles to sandstone mainly relies on the microbial induced formation of magnesium carbonate precipitation around individual particles and at particle-particle contacts.

  8. Early Results of Clinical Application of Autologous Whole Bone Marrow Stem Cell Transplantation for Critical Limb Ischemia with Buerger’s Disease

    Science.gov (United States)

    Heo, Seon-Hee; Park, Yoong-Seok; Kang, Eun-Suk; Park, Kwang-Bo; Do, Young-Soo; Kang, Kyung-Sun; Kim, Dong-Ik

    2016-01-01

    Our goal was to evaluate early results of the clinical application of autologous whole bone marrow stem cell transplantation (AWBMSCT) for critical limb ischemia (CLI) in patients with Buerger’s disease. We retrospectively analyzed the data of 58 limbs of 37 patients (mean age, 43.0 years; range, 28–63 years; male, 91.9%) with Buerger’s disease with CLI who were treated with AWBMSCT from March 2013 to December 2014. We analyzed Rutherford category, pain score, pain-free walking time (PFWT), total walking time (TWT), ankle brachial pressure index (ABPI), and toe brachial pressure index (TBPI), and investigated wound healing and occurrence of unplanned amputations. The mean follow-up duration was 11.9 ± 7.2 months (range, 0.9–23.9 months) and 100%, 72.4%, and 74.1% of patients were available to follow-up 1, 3 and 6 months after AWBMST, respectively. At 6 months, patients demonstrated significant improvements in Rutherford category (P ABPI was increased compared to baseline, but the difference was not significant. A total of 76.5% ischemic wounds achieved complete or improved healing. AWBMSCT is a safe and effective alternative or adjunctive treatment modality to achieve clinical improvement in patients with CLI. PMID:26791280

  9. Stem Cells

    OpenAIRE

    Madhukar Thakur

    2009-01-01

    Objective: The objective of this presentation is to create awareness of stem cell applications in the ISORBE community and to foster a strategy of how the ISORBE community can disseminate information and promote the use of radiolabeled stem cells in biomedical applications. Methods: The continued excitement in Stem Cells, in many branches of basic and applied biomedical science, stems from the remarkable ability of stem cells to divide and develop into different types of cells in ...

  10. Becoming a Blood Stem Cell Donor

    Medline Plus

    Full Text Available ... Institutes of Health Clinical Center in Bethesda, MD. Bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT) are most commonly used in the treatment of cancers like leukemia and lymphoma to restore stem cells ...

  11. Becoming a Blood Stem Cell Donor

    Medline Plus

    Full Text Available ... on Jul 19, 2011 Ever considered becoming a bone marrow or blood stem cell donor? Follow this ... Institutes of Health Clinical Center in Bethesda, MD. Bone marrow transplantation (BMT) and peripheral blood stem cell ...

  12. Becoming a Blood Stem Cell Donor

    Medline Plus

    Full Text Available ... on Jul 19, 2011 Ever considered becoming a bone marrow or blood stem cell donor? Follow this true ... Institutes of Health Clinical Center in Bethesda, MD. Bone marrow transplantation (BMT) and peripheral blood stem cell transplantation ( ...

  13. Cancer Stem Cells in Breast Cancer

    OpenAIRE

    Fumitaka Takeshita; Tomohiro Fujiwara; Takahiro Ochiya; Makiko Ono; Ryou-u Takahashi

    2011-01-01

    The cancer stem cell (CSC) theory is generally acknowledged as an important field of cancer research, not only as an academic matter but also as a crucial aspect of clinical practice. CSCs share a variety of biological properties with normal somatic stem cells in self-renewal, the propagation of differentiated progeny, the expression of specific cell markers and stem cell genes, and the utilization of common signaling pathways and the stem cell niche. However, CSCs differ from normal stem cel...

  14. Evaluation and Comparison of the Effect of Different Surface Preparations on Bond Strength of Glass Ionomer Cement with Nickel–Chrome Metal–Ceramic Alloy: A Laboratory Study

    OpenAIRE

    Hasti, Kalpana; Jagadeesh, H. G.; Patil, Narendra P.

    2011-01-01

    Retention of fixed partial dentures is mostly dependent upon the bond between metal and cement as well as cement and tooth structure. However, most of the time clinical failure of bond has been observed at metal and cement interface. The treatment of metal surface, prior to luting, plays a crucial role in bonding cement with the metal. This study is conducted to evaluate and compare the effect of different surface preparations on the bond strength of resin-modified glass ionomer cement with n...

  15. Clinical significance of uncemented long femoral stem prosthesis in the treatment of Vancouver type B perprosthetic femoral fractures%非骨水泥长柄股骨假体治疗Vancouver B型股骨假体周围骨折

    Institute of Scientific and Technical Information of China (English)

    杨二平; 彭昊; 杜远立; 梁杰

    2016-01-01

    Objective To evaluate the clinical results of femoral revision using an uncemented long femoral stems with wire or memory titanium alloy embracing fixator in the treatment of Vancouver type B2 and B3 periprosthetic femoral fractures. Methods We retrospectively reviewed 17 cases of periprosthetic femoral fracture treated with the un-cemented long femoral stem prosthesis. Of these, eight cases were Vancouver type B2 periprosthetic femoral fractures, and nine cases were Vancouver type B3 periprosthetic femoral fractures. The clinical outcomes were assessed with Harris hip score. Radiological evaluations were conducted using Beals and Tower'criteria, and any complication during the fol-low-up period was recorded. Results The average follow-up period was 41.7 months. The average Harris hip score was 68.2 at the final follow-up. All fractures were united. There was femoral stem subsidence less than 10 mm in 4 cases with-out an evidence of loosening both radiologically and clinically. The radiological results using Beals and Towers' criteria were excellent in eight cases, good in five and poor in four. Conclusion An uncemented long femoral stem prosthesis with wire or memory titanium alloy embracing fixator provides a good fracture stability that promotes fracture healing and offers a successful solution for the management of Vancouver type B2 and B3 periprosthetic femoral fractures.%目的 探讨非骨水泥长柄股骨假体治疗人工髋关节置换术后VancouverB型股骨假体周围骨折的临床疗效.方法 回顾性分析宜昌市第一人民医院骨科2008年5月至2014年9月应用非骨水泥长柄股骨假体行股骨侧翻修结合钢丝或记忆合金环抱器固定治疗的Vancouver B2和B3型股骨假体周围骨折患者的临床资料,其中B2型8例,B3型9例.末次随访时采用Harris评分行髋关节功能评估,采用Beals和Tower标准行影像学评估,并记载随访时不良反应.结果 所有患者均获随访,平均随访41.7个月,末

  16. Effect of process variables on the preparation of artificial bone cements

    Energy Technology Data Exchange (ETDEWEB)

    Santos Junior, J.G.F.; Melo, P.A.; Pinto, J.C., E-mail: pinto@peq.coppe.ufrj.br, E-mail: jjunior@peq.coppe.ufrj.br, E-mail: melo@peq.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Quimica; Pita, V.J.R.R., E-mail: vjpita@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Macromoleculas; Nele, M., E-mail: nele@eq.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica

    2013-10-15

    The present work concerns the preparation of bone cements based on poly(methyl methacrylate) (PMMA), used mainly for prosthesis fixation and cavity filling for correction of human bone failures. A typical bone cement recipe contains methyl methacrylate, which polymerizes in situ during cement application. An inherent problem of this reaction is the large amount of heat released during the cement preparation, which may lead to irreparable damage of living tissues. Optimization of PMMA-based bone cement recipes is thus an important step towards safe and reliable clinical usage of these materials. Important process variables related to the reaction temperature profile and the mixing of the recipe constituents were studied in order to allow for the adequate production of bone cements. It is shown that the average molar mass and size of the PMMA particles used in the production of the bone cement, as well as incorporation of radiopaque contrast, co-monomers and fillers into the bone recipe play fundamental roles in the course of the polymerization reaction. Furthermore, the injection vessel geometry may interfere dramatically with the temperature profile and the time for its occurrence. Finally, it has been observed that the morphology of the PMMA particles strongly affects the mixing of the bone cement components. (author)

  17. Effect of process variables on the preparation of artificial bone cements

    International Nuclear Information System (INIS)

    The present work concerns the preparation of bone cements based on poly(methyl methacrylate) (PMMA), used mainly for prosthesis fixation and cavity filling for correction of human bone failures. A typical bone cement recipe contains methyl methacrylate, which polymerizes in situ during cement application. An inherent problem of this reaction is the large amount of heat released during the cement preparation, which may lead to irreparable damage of living tissues. Optimization of PMMA-based bone cement recipes is thus an important step towards safe and reliable clinical usage of these materials. Important process variables related to the reaction temperature profile and the mixing of the recipe constituents were studied in order to allow for the adequate production of bone cements. It is shown that the average molar mass and size of the PMMA particles used in the production of the bone cement, as well as incorporation of radiopaque contrast, co-monomers and fillers into the bone recipe play fundamental roles in the course of the polymerization reaction. Furthermore, the injection vessel geometry may interfere dramatically with the temperature profile and the time for its occurrence. Finally, it has been observed that the morphology of the PMMA particles strongly affects the mixing of the bone cement components. (author)

  18. Development of Portland cement for orthopedic applications, establishing injectability and decreasing setting times.

    Science.gov (United States)

    Wynn-Jones, Gareth; Shelton, Richard M; Hofmann, Michael P

    2012-11-01

    The injectability of Portland cement (PC) with calcium chloride and calcium nitrate additives was investigated using a syringe with a 2 mm aperture for potential clinical applications such as vertebroplasty. Addition of either additive at 10 wt % increased the quantity of cement extruded through the syringe from approximately 25 wt % for the PC standard, to over 95 wt %. 10 wt % additions of either additive also decreased setting times from over 2 h to below 25 min. The compressive strength of the modified cements was all greater than the compressive strength of a human vertebral body. Decreasing either additive to 5 wt % generated compressive strengths after 24 h setting equal to polymethylmethacrylate, the cement used for the majority of vertebroplasty procedures. An initial early exotherm in the chloride cements was coupled with an X-ray diffraction (XRD) peak that indicated the early formation of the ettringite cement phase. In contrast, Fourier transform infrared (FTIR) spectroscopy and XRD data indicated that calcium nitrate may have stimulated early calcium silicate hydrate (C-S-H) production (the main strength producing phase of PC). Combining the two additives produced a synergistic effect with cements having increased injectabilities and compressive strengths compared with either addition used individually. This study has demonstrated that by modifying PC with nonproprietary chemicals it was possible to significantly increase cement injectability and reduce setting times whilst maintaining compressive strengths, making PC suitable for potential orthopedic applications. PMID:22887643

  19. Physicochemical properties and biocompatibility of chitosan oligosaccharide/gelatin/calcium phosphate hybrid cements

    International Nuclear Information System (INIS)

    A bone substitute material was developed consisting of a chitosan oligosaccharide (COS) solution in a liquid phase and gelatin (GLT) containing calcium phosphate powder in a solid phase. The physicochemical and biocompatible properties of the hybrid cements were evaluated. The addition of COS to cement did not affect the setting time or diametral tensile strength of the hybrid cements, whereas GLT significantly prolonged the setting time and decreased the strength slightly. The setting reaction was inhibited by the addition of GLT to the initial mixture, but not by COS. However, the presence of GLT appreciably improved the anti-washout properties of the hybrid cement compared with COS. COS may promote the cement's biocompatibility as an approximate twofold increase in cell proliferation for 10% COS-containing cements was observed on day 3 as compared with the controls. The combination of GLT and COS was chosen due to the benefits achieved from several synergistic effects and for their clinical applications. Cement with 5% GLT and 10% COS may be a better choice among cements in terms of anti-washout properties and biological activity.

  20. No Superiority of Cemented Metal-on-Metal vs Metal-on-Polyethylene THA at 5-Year Follow-up

    NARCIS (Netherlands)

    Zijlstra, Wierd P.; Cheung, John; Sietsma, Maurits S.; van Raay, Jos J. A. M.; Deutman, Robert

    2009-01-01

    A randomized controlled trial was performed to compare the cemented Stanmore metal-on-metal (Biomet, Warsaw, Indiana) total hip arthroplasty (THA; 102 hips) to the cemented Stanmore metal-on-polyethylene (Biomet) THA (98 hips). The primary outcome was clinical performance. Radiological performance,

  1. Effects of mechanical properties of adhesive resin cements on stress distribution in fiber-reinforced composite adhesive fixed partial dentures.

    Science.gov (United States)

    Yokoyama, Daiichiro; Shinya, Akikazu; Gomi, Harunori; Vallittu, Pekka K; Shinya, Akiyoshi

    2012-01-01

    Using finite element analysis (FEA), this study investigated the effects of the mechanical properties of adhesive resin cements on stress distributions in fiber-reinforced resin composite (FRC) adhesive fixed partial dentures (AFPDs). Two adhesive resin cements were compared: Super-Bond C&B and Panavia Fluoro Cement. The AFPD consisted of a pontic to replace a maxillary right lateral incisor and retainers on a maxillary central incisor and canine. FRC framework was made of isotropic, continuous, unidirectional E-glass fibers. Maximum principal stresses were calculated using finite element method (FEM). Test results revealed that differences in the mechanical properties of adhesive resin cements led to different stress distributions at the cement interfaces between AFPD and abutment teeth. Clinical implication of these findings suggested that the safety and longevity of an AFPD depended on choosing an adhesive resin cement with the appropriate mechanical properties. PMID:22447051

  2. Types of Stem Cells

    Science.gov (United States)

    ... PDF) Download an introduction to stem cells and stem cell research. Stem Cell Glossary Stem cell terms to know. ... stem cells blog from the International Society for Stem Cell Research. Learn About Stem Cells From Lab to You ...

  3. Continuous monitoring of the zinc-phosphate acid-base cement setting reaction by proton nuclear magnetic relaxation

    Science.gov (United States)

    Apih, T.; Lebar, A.; Pawlig, O.; Trettin, R.

    2001-06-01

    Proton nuclear magnetic relaxation is a well-established technique for continuous and non destructive monitoring of hydration of conventional Portland building cements. Here, we demonstrate the feasibility of nuclear magnetic resonance (NMR) monitoring of the setting reaction of zinc-phosphate acid-base dental cements, which harden in minutes as compared to days, as in the case of Portland cements. We compare the setting of cement powder (mainly, zinc oxide) prepared with clinically used aluminum-modified orthophosphoric acid solution with the setting of a model system where cement powder is mixed with pure orthophosphoric acid solution. In contrast to previously published NMR studies of setting Portland cements, where a decrease of spin-lattice relaxation time is attributed to enhanced relaxation at the growing internal surface, spin-lattice relaxation time T1 increases during the set of clinically used zinc-phosphate cement. Comparison of these results with a detailed study of diffusion, viscosity, and magnetic-field dispersion of T1 in pure and aluminum-modified orthophosphoric acid demonstrates that the increase of T1 in the setting cement is connected with the increase of molecular mobility in the residual phosphoric acid solution. Although not taken into account so far, such effects may also significantly influence the relaxation times in setting Portland cements, particularly when admixtures with an effect on water viscosity are used.

  4. Continuous monitoring of the zinc-phosphate acid-base cement setting reaction by proton nuclear magnetic relaxation

    International Nuclear Information System (INIS)

    Proton nuclear magnetic relaxation is a well-established technique for continuous and non destructive monitoring of hydration of conventional Portland building cements. Here, we demonstrate the feasibility of nuclear magnetic resonance (NMR) monitoring of the setting reaction of zinc-phosphate acid-base dental cements, which harden in minutes as compared to days, as in the case of Portland cements. We compare the setting of cement powder (mainly, zinc oxide) prepared with clinically used aluminum-modified orthophosphoric acid solution with the setting of a model system where cement powder is mixed with pure orthophosphoric acid solution. In contrast to previously published NMR studies of setting Portland cements, where a decrease of spin-lattice relaxation time is attributed to enhanced relaxation at the growing internal surface, spin-lattice relaxation time T1 increases during the set of clinically used zinc-phosphate cement. Comparison of these results with a detailed study of diffusion, viscosity, and magnetic-field dispersion of T1 in pure and aluminum-modified orthophosphoric acid demonstrates that the increase of T1 in the setting cement is connected with the increase of molecular mobility in the residual phosphoric acid solution. Although not taken into account so far, such effects may also significantly influence the relaxation times in setting Portland cements, particularly when admixtures with an effect on water viscosity are used. [copyright] 2001 American Institute of Physics

  5. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    LENUS (Irish Health Repository)

    Addison, Owen

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic.

  6. Retention of Root Canal Posts: Effect of Cement Film Thickness, Luting Cement, and Post Pretreatment

    DEFF Research Database (Denmark)

    Sahafi, Alireza; Benetti, Ana Raquel; Peutzfeldt, Anne; Flury, Simon

    2015-01-01

    The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc...

  7. [Antimicrobial activity of orthodontic band cements].

    Science.gov (United States)

    Pavic, J; Arriagada, M; Elgueta, J; García, C

    1990-01-01

    The prevalence of enamel decalcification and caries beneath orthodontic bands, has indicated the need for a new enamel binding adhesive orthodontic cement. The purpose of this study was to evaluate the antimicrobial activity, in vitro, on Streptococcus mutans and Lactobacillus, acidophillus, of three materials used to cements the orthodontic bands. The cements studied were: Zinc phosphate cement, Glass-ionomer cement, and Policarboxylate cement. Thirty petri plates were seeded with S. mutans, and thirty with L. acidophillus; on each plate three pellet were placed, one of each cement studied. Petri plates were incubated under microaerophilic conditions at 37 C, and checked at 72 hrs. for Streptococcus, mutans, and four days for Lactobacillus acidophillus to evaluate the inhibition zone. The results were tabulated for each material. It was demonstrated that exists important variations in the antimicrobial properties of the materials studied, as in the microbial sensitivity to these cements. PMID:2135908

  8. Yin Yang 1 is associated with cancer stem cell transcription factors (SOX2, OCT4, BMI1) and clinical implication.

    Science.gov (United States)

    Kaufhold, Samantha; Garbán, Hermes; Bonavida, Benjamin

    2016-01-01

    The transcription factor Yin Yang 1 (YY1) is frequently overexpressed in cancerous tissues compared to normal tissues and has regulatory roles in cell proliferation, cell viability, epithelial-mesenchymal transition, metastasis and drug/immune resistance. YY1 shares many properties with cancer stem cells (CSCs) that drive tumorigenesis, metastasis and drug resistance and are regulated by overexpression of certain transcription factors, including SOX2, OCT4 (POU5F1), BMI1 and NANOG. Based on these similarities, it was expected that YY1 expression would be associated with SOX2, OCT4, BMI1, and NANOG's expressions and activities. Data mining from the proteomic tissue-based datasets from the Human Protein Atlas were used for protein expression patterns of YY1 and the four CSC markers in 17 types of cancer, including both solid and hematological malignancies. A close association was revealed between the frequency of expressions of YY1 and SOX2 as well as SOX2 and OCT4 in all cancers analyzed. Two types of dynamics were identified based on the nature of their association, namely, inverse or direct, between YY1 and SOX2. These two dynamics define distinctive patterns of BMI1 and OCT4 expressions. The relationship between YY1 and SOX2 expressions as well as the expressions of BMI1 and OCT4 resulted in the classification of four groups of cancers with distinct molecular signatures: 1) Prostate, lung, cervical, endometrial, ovarian and glioma cancers (YY1(lo)SOX2(hi)BMI1(hi)OCT4(hi)) 2) Skin, testis and breast cancers (YY1(hi)SOX2(lo)BMI1(hi)OCT4(hi)) 3) Liver, stomach, renal, pancreatic and urothelial cancers (YY1(lo)SOX2(lo)BMI1(hi)OCT4(hi)) and 4) Colorectal cancer, lymphoma and melanoma (YY1(hi)SOX2(hi)BMI1(lo)OCT4(hi)). A regulatory loop is proposed consisting of the cross-talk between the NF-kB/PI3K/AKT pathways and the downstream inter-regulation of target gene products YY1, OCT4, SOX2 and BMI1. PMID:27225481

  9. Cement radwaste solidification studies third annual report

    International Nuclear Information System (INIS)

    This report summarises cement radwaste studies carried out at AEE Winfrith during 1981 on the encapsulation of medium and low active waste in cement. During the year more emphasis has been placed on the work which is directly related to the solidification of SGHWR active sludge. Information has been obtained on the properties of 220 dm3 drums of cemented waste. The use of cement grouts for the encapsulation of solid items has also been investigated during 1981. (U.K.)

  10. Cement Sheath Integrity During Thermal Cycling

    OpenAIRE

    Andrade, Jesús De

    2015-01-01

    In the construction process of oil and gas wells, primary cementing constitutes a critical procedure of placing a cement sheath in the annulus between casing and formation, or between the casing strings. The main purpose is to provide mechanical stability to the wellbore and to ensure zonal isolation through the entire well service lifetime. Failures to achieve a proper primary cementing, and to ensure long-term sealing capabilities of the cement sheath, may severely limit the abi...

  11. Neutron Scattering Studies of Cement

    Science.gov (United States)

    Allen, Andrew

    2010-03-01

    Despite more than a century of research, basic questions remain regarding both the internal structure and the role of water in Ordinary Portland cement (OPC) concrete, the world's most widely used manufactured material. Most such questions concern the primary hydration product and strength-building phase of OPC paste, the calcium silicate hydrate (C-S-H) gel. When cement and water are mixed, this phase precipitates as clusters of nanoscale (nearly amorphous) colloidal particles with an associated water-filled inter-particle pore system. Most attempts to characterize the C-S-H gel and the behavior of the associated water involve drying or other processes that, themselves, change the bound water content within and around the gel. Neutron scattering methods do not suffer from this disadvantage. Furthermore, the neutron isotope effect and the neutron's sensitivity to molecular motion have enabled considerable progress to be made in recent years by: (i) determining the C-S-H composition, density and gel structure in small-angle neutron scattering (SANS) H/D contrast variation studies; (ii) elucidating the changing state of water within cement as hydration progresses using quasielastic neutron scattering (QENS); and (iii) measuring the production and consumption of nanoscale calcium hydroxide (CH), a by-product of cement hydration that co-exists with the C-S-H gel, using inelastic neutron scattering (INS). These experiments have provided new insights into the physics and chemistry of cement hydration, and have implications for the design of new concretes with pozzolanic cement additions that are intended to address environmental concerns and sustainability issues.

  12. ADVANCED CEMENTS FOR GEOTHERMAL WELLS

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well

  13. PERFORMANCE OF PULVERIZED SLAG-SUBSTITUTED CEMENT

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.

  14. Clinical Efficacy of Bone Cement Hemiarthroplasty Combined with Wire Cerclage in Treatment of Elderly Pa-tients with Intertrochanteric Fracture%骨水泥半髋置换加钢丝环扎术治疗老年粗隆间骨折疗效探讨

    Institute of Scientific and Technical Information of China (English)

    谌思; 金伟

    2015-01-01

    Objective To investigate the clinical efficacy of bone cement hemiarthroplasty combined with wire cerclage in treatment of elderly patients with intertrochanteric fracture. Methods A total of 63 elderly patients with in-tertrochanteric fracture during October 2010 and October 2013 were randomly divided into dynamic hip screw group (DHS group, n = 21), proximal femoral nail antirotation group (PFNA group, n = 21) and bone cement hemiarthroplasty com-bined with wire cerclage group (FHR group, n = 21). The operation time, intraoperative bleeding volume, full weight bearing time, fracture healing time, Harris score and postoperative adverse reaction in the three groups were compared. Results In FHR group, the operation time was significantly longer than that of other groups (P 0. 05). The incidence rate of adverse reaction in FHR group was significantly lower than those in DHS and PFNA groups (P 0.05)。 FHR 组患者术后不良反应发生率显著低于 DHS 组和 PFNA 组(P <0.01)。结论骨水泥半髋置换加钢丝环扎术治疗老年粗隆间骨折耗时较长,术中出血量较多但术后不良反应较少且恢复较快。

  15. Microscale Investigation of Arsenic Distribution and Species in Cement Product from Cement Kiln Coprocessing Wastes

    OpenAIRE

    Yufei Yang; Jingchuan Xue; Qifei Huang

    2013-01-01

    To improve the understanding of the immobilization mechanism and the leaching risk of Arsenic (As) in the cement product from coprocessing wastes using cement kiln, distribution and species of As in cement product were determined by microscale investigation methods, including electron probe microanalysis (EPMA) and X-ray absorption spectroscopy. In this study, sodium arsenate crystals (Na3AsO412H2O) were mixed with cement production raw materials and calcined to produce cement clinker. Then, ...

  16. The comparison between sulfate salt weathering of portland cement paste and calcium sulfoaluminate cement paste

    OpenAIRE

    Liu, Zanqun; Deng, Dehua; De Schutter, Geert

    2015-01-01

    In this paper, the damage performances of sulfate salt weathering of Portland cement paste and calcium sulfoaluminate (CSA) cement paste were compared according to authors' previous studies. It was found that the evaporation zone of speciments partially immersed in 10% Na2SO4 solution were both severely deteriorated for Portland cement and CSA cement. However, the differences were more significant: (1) the CSA cement paste were damaged just after 7 days exposure compared to the 5 months expos...

  17. Comparative Characterization of Cells from the Various Compartments of the Human Umbilical Cord Shows that the Wharton's Jelly Compartment Provides the Best Source of Clinically Utilizable Mesenchymal Stem Cells.

    Directory of Open Access Journals (Sweden)

    Arjunan Subramanian

    Full Text Available The human umbilical cord (UC is an attractive source of mesenchymal stem cells (MSCs with unique advantages over other MSC sources. They have been isolated from different compartments of the UC but there has been no rigorous comparison to identify the compartment with the best clinical utility. We compared the histology, fresh and cultured cell numbers, morphology, proliferation, viability, stemness characteristics and differentiation potential of cells from the amnion (AM, subamnion (SA, perivascular (PV, Wharton's jelly (WJ and mixed cord (MC of five UCs. The WJ occupied the largest area in the UC from which 4.61 ± 0.57 x 106 /cm fresh cells could be isolated without culture compared to AM, SA, PV and MC that required culture. The WJ and PV had significantly lesser CD40+ non-stem cell contaminants (26-27% compared to SA, AM and MC (51-70%. Cells from all compartments were proliferative, expressed the typical MSC-CD, HLA, and ESC markers, telomerase, had normal karyotypes and differentiated into adipocyte, chondrocyte and osteocyte lineages. The cells from WJ showed significantly greater CD24+ and CD108+ numbers and fluorescence intensities that discriminate between MSCs and non-stem cell mesenchymal cells, were negative for the fibroblast-specific and activating-proteins (FSP, FAP and showed greater osteogenic and chondrogenic differentiation potential compared to AM, SA, PV and MC. Cells from the WJ offer the best clinical utility as (i they have less non-stem cell contaminants (ii can be generated in large numbers with minimal culture avoiding changes in phenotype, (iii their derivation is quick and easy to standardize, (iv they are rich in stemness characteristics and (v have high differentiation potential. Our results show that when isolating MSCs from the UC, the WJ should be the preferred compartment, and a standardized method of derivation must be used so as to make meaningful comparisons of data between research groups.

  18. Comparative Characterization of Cells from the Various Compartments of the Human Umbilical Cord Shows that the Wharton's Jelly Compartment Provides the Best Source of Clinically Utilizable Mesenchymal Stem Cells.

    Science.gov (United States)

    Subramanian, Arjunan; Fong, Chui-Yee; Biswas, Arijit; Bongso, Ariff

    2015-01-01

    The human umbilical cord (UC) is an attractive source of mesenchymal stem cells (MSCs) with unique advantages over other MSC sources. They have been isolated from different compartments of the UC but there has been no rigorous comparison to identify the compartment with the best clinical utility. We compared the histology, fresh and cultured cell numbers, morphology, proliferation, viability, stemness characteristics and differentiation potential of cells from the amnion (AM), subamnion (SA), perivascular (PV), Wharton's jelly (WJ) and mixed cord (MC) of five UCs. The WJ occupied the largest area in the UC from which 4.61 ± 0.57 x 106 /cm fresh cells could be isolated without culture compared to AM, SA, PV and MC that required culture. The WJ and PV had significantly lesser CD40+ non-stem cell contaminants (26-27%) compared to SA, AM and MC (51-70%). Cells from all compartments were proliferative, expressed the typical MSC-CD, HLA, and ESC markers, telomerase, had normal karyotypes and differentiated into adipocyte, chondrocyte and osteocyte lineages. The cells from WJ showed significantly greater CD24+ and CD108+ numbers and fluorescence intensities that discriminate between MSCs and non-stem cell mesenchymal cells, were negative for the fibroblast-specific and activating-proteins (FSP, FAP) and showed greater osteogenic and chondrogenic differentiation potential compared to AM, SA, PV and MC. Cells from the WJ offer the best clinical utility as (i) they have less non-stem cell contaminants (ii) can be generated in large numbers with minimal culture avoiding changes in phenotype, (iii) their derivation is quick and easy to standardize, (iv) they are rich in stemness characteristics and (v) have high differentiation potential. Our results show that when isolating MSCs from the UC, the WJ should be the preferred compartment, and a standardized method of derivation must be used so as to make meaningful comparisons of data between research groups. PMID:26061052

  19. GPCRs in Stem Cell Function

    OpenAIRE

    Doze, Van A.; PEREZ, DIANNE M.

    2013-01-01

    Many tissues of the body cannot only repair themselves, but also self-renew, a property mainly due to stem cells and the various mechanisms that regulate their behavior. Stem cell biology is a relatively new field. While advances are slowly being realized, stem cells possess huge potential to ameliorate disease and counteract the aging process, causing its speculation as the next panacea. Amidst public pressure to advance rapidly to clinical trials, there is a need to understand the biology o...

  20. Stress Transfer Modeling at the Interface of Cemented Prosthesis and Femur

    Institute of Scientific and Technical Information of China (English)

    YU Xue-zhong; GUO Yi-mu; ZHANG Yun-qiu; LI Jun; HE Rong-xing

    2008-01-01

    .Objective:To model the stress transfer at the interface of the cemented prosthesis and femur, an axisymmetric model of the interfacial stress transfer was established.Methods: Assuming that the prosthesis, the cement and the femur were concentric cylinders with linear elastic and isotropic properties, distributions of the axial stresses in the prosthesis, the cement and the femur as well as the interfacial shear stresses at the prosthesis/cement interface and the cement/femur interface in the axial direction were obtained from the established axisymmetric stress transfer model.Results: Interfacial failure was the main form for the prosthesis/cement/femur structure under external loads. Considering the residual thermal stresses, it was more likely to produce the mixed failure form than the pure shear failure form. Since the cement had a relatively high thermal expansion coefficient, the thermal effect accelerated the interface failure and thus aggravated the stress shielding effect. Due to a relatively high thermal residual temperature difference, the interfacial debonding and femur failure was more likely to occur for the cobalt-chromium alloy prosthesis material than the Ti-6Al-4V alloy prosthesis material.Conclusion: Assuming that the prosthesis, the cement and the femur are concentric cylinders with linear elastic and isotropic properties, distributions of the axial stresses in the prosthesis, the cement and the femur as well as the interfacial shear stresses at the prosthesis/cement interface and the cement/femur interface in the axial direction was obtained using the basic equations of axisymmetric elastic mechanics when the prosthesis bears the compressive stresses. Interface failure is the main failure form for the prosthesis/cement/femur structure under external loads. The thermal effects accelerate the failure of the prosthesis/cement interface and the cement/femur interface and the relaxation of the prosthesis, and then aggravates the stress shielding

  1. Chimerism analysis in clinical practice and its relevance for the detection of graft rejection and malignant relapse in pediatric hematopoietic stem cell transplant patients.

    Science.gov (United States)

    Mellgren, Karin; Arvidson, Johan; Toporski, Jacek; Winiarski, Jacek

    2015-11-01

    Chimerism and clinical outcome data from 244 hematopoietic stem cell transplants in 218 children were retrospectively analyzed to assess their relevance for the detection of graft rejection and malignant relapse. Patients transplanted for a non-malignant disease had significantly higher proportions of residual recipient T cells in peripheral blood at one, three, and six months compared with patients transplanted for malignant disease. Recipient T-cell levels were below 50% at one month after transplantation in most patients (129 of 152 transplants). Graft rejection occurred more frequently in the group of patients with high levels of recipient cells at one month (10 graft rejections in the 23 patients with recipient T cells >50% at one month as compared to seven graft rejections occurred in 129 patients with recipient T cells <50% (p < 0.001). Multilineage chimerism data in 87 children with leukemia at one, three, and six months after transplantation were not correlated with subsequent relapse of malignant disease. In conclusion, early analysis of lineage-specific chimerism in peripheral blood can be used to identify patients who are at high risk of graft rejection. However, the efficacy of early chimerism analysis for predicting leukemia relapse was limited. PMID:26290161

  2. Clinical-scale laser-based scanning and processing of live cells: selective photothermal killing of fluorescent tumor targets for autologous stem cell transplantation

    Science.gov (United States)

    Koller, Manfred R.; Hanania, Elie G.; Eisfeld, Timothy; O'Neal, Robert A.; Khovananth, Kevin M.; Palsson, Bernhard O.

    2001-04-01

    High-dose chemotherapy, followed by autologous hematopoietic stem cell (HSC) transplantation, is widely used for the treatment of cancer. However, contaminating tumor cells within HSC harvests continue to be of major concern since re-infused tumor cells have proven to contribute to disease relapse. Many tumor purging methods have been evaluated, but all leave detectable tumor cells in the transplant and result in significant loss of HSCs. These shortcomings cause engraftment delays and compromise the therapeutic value of purging. A novel approach integrating automated scanning cytometry, image analysis, and selective laser-induced killing of labeled cells within a cell mixture is described here. Non-Hodgkin's lymphoma (NHL) cells were spiked into cell mixtures, and fluorochrome-conjugated antibodies were used to label tumor cells within the mixture. Cells were then allowed to settle on a surface, and as the surface was scanned with a fluorescence excitation source, a laser pulse was fired at every detected tumor cell using high-speed beam steering mirrors. Tumor cells were selectively killed with little effect on adjacent non-target cells, demonstrating the feasibility of this automated cell processing approach. This technology has many potential research and clinical applications, one example of which is tumor cell purging for autologous HSC transplantation.

  3. Mesenchymal Stem Cells and Tooth Engineering

    Institute of Scientific and Technical Information of China (English)

    Li Peng; Ling Ye; Xue-dong Zhou

    2009-01-01

    Tooth loss compromises human oral health. Although several prosthetic methods, such as artificial denture and dental implants, are clinical therapies to tooth loss problems, they are thought to have safety and usage time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSCs) are multipotent stem cells which can differentiate into a variety of cell types. The potential MSCs for tooth regeneration mainly include stem cells from human exfoliated deciduous teeth (SHEDs), adult dental pulp stem cells (DPSCs), stem cells from the apical part of the papilla (SCAPs), stem cells from the dental follicle (DFSCs), periodontal ligament stem cells (PDLSCs) and bone marrow derived mesenchymal stem cells (BMSCs). This review outlines the recent progress in the mesenchymal stem cells used in tooth regeneration.

  4. Thoughts on the Current Cement Industry Development

    Institute of Scientific and Technical Information of China (English)

    Gan Zhihe

    2003-01-01

    According to the analysis of cement capacity andits relations with macro economy running index, the mainreasons for the present rapid development of cement capacityare the rapid development of economy and the shot up ofwhole society fixed asset investment. According to the presentspeed of economy development, cement still enjoys a po-tential increase, So here has not been an overall excessivepopularity of cement industry. The best way to prevent lowlevel repeated construction is to promote the development ofnew dry- process cement as well as try to get rid of blindness.

  5. Special recipe for cement solidification

    International Nuclear Information System (INIS)

    ABB Atom's MOSS is a compact, mobile system for immobilizing radwaste in cement. Various ''recipes'' have been developed to meet stringent end product requirements. A version of MOSS, described here, was delivered to Borssele last year and has completed two solidification campaigns to date. (author)

  6. Effect of temporary cements on the shear bond strength of luting cements

    Directory of Open Access Journals (Sweden)

    Marco Fiori-Júnior

    2010-02-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate, by shear bond strength (SBS testing, the influence of different types of temporary cements on the final cementation using conventional and self-etching resin-based luting cements. Material and Methods: Forty human teeth divided in two halves were assigned to 8 groups (n=10: I and V (no temporary cementation; II and VI: Ca(OH2-based cement; III and VII: zinc oxide (ZO-based cement; IV and VIII: ZO-eugenol (ZOE-based cement. Final cementation was done with RelyX ARC cement (groups I to IV and RelyX Unicem cement (groups V to VIII. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. RESULTS: Means were (MPa: I - 3.80 (±1.481; II - 5.24 (±2.297; III - 6.98 (±1.885; IV - 6.54 (±1.459; V - 5.22 (±2.465; VI - 4.48 (±1.705; VII - 6.29 (±2.280; VIII - 2.47 (±2.076. Comparison of the groups that had the same temporary cementation (Groups II and VI; III and VII; IV and VIII showed statistically significant difference (p0.05 for the different luting cements (RelyX TM ARC and RelyX TM Unicem. The groups that had no temporary cementation (Groups I and V did not differ significantly from each other either (p>0.05. CONCLUSION: When temporary cementation was done with ZO- or ZOE-based cements and final cementation was done with RelyX ARC, there was an increase in the SBS compared to the control. In the groups cemented with RelyX Unicem, however, the use of a ZOE-based temporary cement affected negatively the SBS of the luting agent used for final cementation.

  7. Induced pluripotent stem cells

    Institute of Scientific and Technical Information of China (English)

    Siddhartha Bhowmik; LI Yong

    2011-01-01

    Induced pluripotent stem (iPS) cells are a recent development which has brought a promise of great therapeutic values. The previous technique of somatic cell nuclear transfer (SCNT) has been ineffective in humans. Recent discoveries show that human fibroblasts can be reprogrammed by a transient over expression of a small number of genes; they can undergo induced pluripotency. iPS were first produced in 2006. By 2008, work was underway to remove the potential oncogenes from their structure. In 2009, protein iPS (piPS) cells were discovered. Surface markers and reporter genes play an important role in stem cell research. Clinical applications include generation of self renewing stem cells, tissue replacement and many more. Stem cell therapy has the ability to dramatically change the treatment of human diseases.

  8. Mesoscale texture of cement hydrates.

    Science.gov (United States)

    Ioannidou, Katerina; Krakowiak, Konrad J; Bauchy, Mathieu; Hoover, Christian G; Masoero, Enrico; Yip, Sidney; Ulm, Franz-Josef; Levitz, Pierre; Pellenq, Roland J-M; Del Gado, Emanuela

    2016-02-23

    Strength and other mechanical properties of cement and concrete rely upon the formation of calcium-silicate-hydrates (C-S-H) during cement hydration. Controlling structure and properties of the C-S-H phase is a challenge, due to the complexity of this hydration product and of the mechanisms that drive its precipitation from the ionic solution upon dissolution of cement grains in water. Departing from traditional models mostly focused on length scales above the micrometer, recent research addressed the molecular structure of C-S-H. However, small-angle neutron scattering, electron-microscopy imaging, and nanoindentation experiments suggest that its mesoscale organization, extending over hundreds of nanometers, may be more important. Here we unveil the C-S-H mesoscale texture, a crucial step to connect the fundamental scales to the macroscale of engineering properties. We use simulations that combine information of the nanoscale building units of C-S-H and their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles. We compute small-angle scattering intensities, pore size distributions, specific surface area, local densities, indentation modulus, and hardness of the material, providing quantitative understanding of different experimental investigations. Our results provide insight into how the heterogeneities developed during the early stages of hydration persist in the structure of C-S-H and impact the mechanical performance of the hardened cement paste. Unraveling such links in cement hydrates can be groundbreaking and controlling them can be the key to smarter mix designs of cementitious materials. PMID:26858450

  9. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll; Dam-Johansen, Kim; Hjuler, Klaus

    2013-01-01

    The cement industry is one of the major sources of CO2 emissions and is likely to contribute to further increases in the near future. The carbonate looping process has the potential to capture CO2 emissions from the cement industry, in which raw meal for cement production could be used as the...... sorbent. Cyclic experiments were carried out in a TGA apparatus using industrial cement raw meal and synthetic raw meal as sorbents, with limestone as the reference. The results show that the CO2 capture capacities of the cement raw meal and the synthetic raw meal are comparable to those of pure limestone...... capacity (Xr). This shows that raw meal could be used as a sorbent for the easy integration of the carbonate looping process into the cement pyro process for reducing CO2 emissions from the cement production process....

  10. Leaching of tritium from a cement composite

    International Nuclear Information System (INIS)

    Leaching of tritium from cement composites into an aqueous phase has been studied to evaluate the safety of incorporation of the tritiated liquid waste into cement. Leaching tests were performed by the method recommended by the International Atomic Energy Agency. The Leaching fraction was measured as functions of waste-cement ratio (Wa/C), temperature of leachant and curing time. The tritium leachability of cement in the long term test follows the order: alumina cement portland cement slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than synthetic sea water. The amount leached of tritium from a 200 l drum size specimen was estimated on the basis of the above results. (author)

  11. Migration and head penetration of Vitamin-E diffused cemented polyethylene cup compared to standard cemented cup in total hip arthroplasty: study protocol for a randomised, double-blind, controlled trial (E1 HIP)

    Science.gov (United States)

    Sköldenberg, Olof; Rysinska, Agata; Chammout, Ghazi; Salemyr, Mats; Muren, Olle; Bodén, Henrik; Eisler, Thomas

    2016-01-01

    Introduction In vitro, Vitamin-E-diffused, highly cross-linked polyethylene (PE) has been shown to have superior wear resistance and improved mechanical properties when compared to those of standard highly cross-linked PE liners used in total hip arthroplasty (THA). The aim of the study is to evaluate the safety of a new cemented acetabular cup with Vitamin-E-doped PE regarding migration, head penetration and clinical results. Methods and analysis In this single-centre, double-blinded, randomised controlled trial, we will include 50 patients with primary hip osteoarthritis scheduled for THA and randomise them in a 1:1 ratio to a cemented cup with either argon gas-sterilised PE (control group) or Vitamin-E-diffused PE (vitamin-e group). All patients and the assessor of the primary outcome will be blinded and the same uncemented stem will be used for all participants. The primary end point will be proximal migration of the cup at 2 years after surgery measured with radiostereometry. Secondary end points include proximal migration at other follow-ups, total migration, femoral head penetration, clinical outcome scores and hip-related complications. Patients will be followed up at 3 months and at 1, 2, 5 and 10 years postoperatively. Results Results will be analysed using 95% CIs for the effect size. A regression model will also be used to adjust for stratification factors. Ethics and dissemination The ethical committee at Karolinska Institutet has approved the study. The first results from the study will be disseminated to the medical community via presentations and publications in relevant medical journals when the last patient included has been followed up for 2 years. Trial registration number NCT02254980. PMID:27388352

  12. 骨水泥钉道强化联合空心侧孔椎弓根螺钉治疗伴骨质疏松症的腰椎退行性病变的临床疗效观察%Comparison of the clinical effect of PMMA bone cement augmented screw passageway and bone cement-injectable cannulated pedicle screw in treatment of degenerative lumbar disease with osteoporosis

    Institute of Scientific and Technical Information of China (English)

    刘松明; 宋洁富; 荆志振

    2016-01-01

    目的:比较空心侧孔椎弓根螺钉和骨水泥钉道( PMMA)强化方法应用于伴骨质疏松症的腰椎退行性病变的临床效果。方法选取伴骨质疏松症的腰椎退行性病变患者48例,男21例,女27例;年龄54~78岁,平均64.5岁。其中腰椎管狭窄症17例,腰椎间盘突出症18例,退行性腰椎滑脱症8例,腰椎退行性侧凸5例。按手术方式分为两组,A组23例采用空心侧孔椎弓根螺钉+PMMA。 B组25例采用PMMA行钉道强化+普通椎弓根螺钉内固定术。比较两组手术时间、出血量、住院时间。采用疼痛视觉模拟量表( visual analogue scale,VAS)评分,Oswestry功能障碍指数( Oswestry disability index,ODI)评价患者术后疼痛和功能恢复情况。术前及术后1、3、6、12个月及术后每年行X线检查评估椎间隙高度丢失、内固定失败率和椎间植骨融合率。结果48例患者均得到随访,随访时间1~3.5年。 A组手术时间、出血量、住院时间显著优于B组(均P<0.05)。 A组、B组植骨融合率分别为92.1%、91.2%,两组差异无统计学意义( P>0.05)。A组发生螺钉断裂1例,B组未出现此类情况(P<0.05)。 B组发生内固定松动、螺钉拔出内固定失败1例, A组未发生此类情况(P<0.05)。 A组椎间隙高度丢失(2.7±1.7)mm,B组椎间隙高度丢失(3.7±2.1)mm,两组差异有统计学意义(P<0.05)。根据VAS评分和ODI,两组患者术后疼痛与功能均得到改善,A组效果优于B组(均P<0.05)。结论空心侧孔椎弓根螺钉+PMMA强化内固定用于伴骨质疏松症的腰椎退行性病变是一种具有较好安全性和有效性的方法。%Objective To compare the clinical effect of PMMA bone cement augmented screw passageway and bone cement-injectable cannulated pedicle screw in treatment of degenerative lumbar disease with osteoporosis. Methods

  13. Management of a Fractured Multiunit Maxillary Implant-Supported Fixed Prosthesis with Stripped Abutment Screws Using a Hybrid Cement-Retained and Screw-Retained Design: A 5-Year Follow-Up Clinical Report.

    Science.gov (United States)

    Al Amri, Mohammad D

    2016-06-01

    Fracture and loosening of implant-supported prostheses (ISPs) are complications encountered in routine dental practice. In the present report, management of a fractured maxillary full-arch cement-retained (CR) fixed dental prosthesis supported by six implants is presented. Due to stripped screws, complications were encountered that prevented the retrieval of two of the six abutment screws, which was managed by using a hybrid retention approach, whereby a single full-arch CR and screw-retained (SR) ISP was used. The techniques used to successfully retrieve four of the abutment screws are described. The final retention design involved a combination of three CR and three SR restorations, which offers the advantages of both retention designs. PMID:26713868

  14. 自体骨髓干细胞治疗肝硬化基础研究与临床应用现状%Basic and clinical research of autologous bone marrow stem cells in treatment of hepatic cirrhosis

    Institute of Scientific and Technical Information of China (English)

    邢旎旎; 李孝生

    2011-01-01

    BACKGROUND: Liver transplantation is still facing many problems, such as lack of donor livers, immune rejection after transplantation and its high costs, thus making it restricted in clinic application. OBJECTIVE: To describe autologous bone marrow stem cell transplantation in the clinical stage as one of the most promising technology that autologous bone marrow stem cells can differentiate into mature liver cells to replace the damaged liver functioning, which can improve symptoms and quality of life in patients. METHODS: A computer-based online search of PubMed database, CNKI, Wanfang database and VIP database was performed for articles regarding autologous bone marrow stem cells to treat hepatic cirrhosis, with the key words of “bone marrow stem cell, autologous bone marrow stem cell transplantation, hepatic cirrhosis” in Chinese and “bone marrow stem cell, autologous bone marrow stem cell, hepatic cirrhosis” in English. Relevant articles published in recent years or in authorized journals were preferred. Repetitive studies were excluded. Finally, 20 articles were included. RESULTS AND CONCLUSION: Basic and clinical research about autologous bone marrow stem cell transplantation indicate that autologous bone marrow stem cell transplantation has a broad prospect in the treatment of hepatic cirrhosis.%背景:活体肝移植仍面临很多问题:如供体的匮乏、移植后的免疫排异反应及其高额的费用等,因此使其在临床上的开展受到限制.目的:说明自体骨髓干细胞移植可以分化成熟肝细胞而替代受损的肝脏组织发挥功能,从而改善患者症状,提高患者生活质量.方法:利用计算机在PubMed、CNKI、万方数据库和维普数据库中检索2000-01/2010-12关于自体骨髓干细胞移植相关文章,在标题和摘要中用"骨髓干细胞;自体骨髓干细胞移植;肝硬化"或"Bone marrow stem cell,autologous bone marrow stem cell,hepatic cirrhosis"为检索词进行检索.选择与骨髓

  15. Use of zinc phosphate cement as a luting agent for Denzir™ copings: an in vitro study

    Directory of Open Access Journals (Sweden)

    Mondragon Eduardo

    2003-02-01

    Full Text Available Abstract Background The clinical success rate with zinc phosphate cemented Procera crowns is high. The objective with this study was to determine whether CADCAM processed and zinc phosphate cemented Denzir copings would perform as well as zinc phosphate cemented Procera copings when tested in vitro in tension. Methods Twelve Procera copings and twenty-four Denzir copings were made. After the copings had been made, twelve of the Denzir copings were sandblasted on their internal surfaces. All copings were then cemented with zinc phosphate cement to carbon steel dies and transferred to water or artificial saliva. Two weeks after cementation, half of the samples were tested. The remaining samples were tested after one year in the storage medium. All tests were done in tension and evaluated with an ANOVA. Results Sandblasted and un-sandblasted Denzir copings performed as well as Procera copings. Storage in water or artificial saliva up to one year did not decrease the force needed to dislodge any of the coping groups. Three copings fractured during testing and one coping developed a crack during testing. The three complete fractures occurred in Procera copings, while the partly cracked coping was a Denzir coping. Conclusion No significant differences existed between the different material groups, and the retentive force increased rather than decreased with time. Fewer fractures occurred in Denzir copings, explained by the higher fracture toughness of the Denzir material. Based on good clinical results with zinc phosphate cemented Procera crowns, we foresee that zinc phosphate cement luted Denzir copings are likely to perform well clinically.

  16. Blood-Forming Stem Cell Transplants

    Science.gov (United States)

    ... Health Professionals Questions to Ask about Your Treatment Research Blood-Forming Stem Cell Transplants On This Page What are bone marrow ... are evaluating BMT and PBSCT in clinical trials (research studies) for the treatment ... are the donor’s stem cells matched to the patient’s stem cells in allogeneic ...

  17. The cement recycling of the earthquake disaster debris by Hachinohe Cement Co., Ltd

    International Nuclear Information System (INIS)

    A tremendous quantity of earthquake disaster debris and tsunami sediment was resulted by the Great East Japan Earthquake on March 11, 2011. Hachinohe Cement Co., Ltd., a Sumitomo Osaka Cement subsidiary, was the first cement industry company to receive and process such waste materials outside of their usual prefecture area, while the company is performing their treatment and recycling services locally in Hachinohe City and Aomori Prefecture. This report provides an explanation about the recycling mechanism of waste materials and by-products in cement manufacturing process, and introduces an example of actual achievements for the disaster debris treatment by utilizing the cement recycling technologies at the Hachinohe Cement Plant. (author)

  18. Investigation progress of imaging techniques monitoring stem cell therapy

    International Nuclear Information System (INIS)

    Recently stem cell therapy has showed potential clinical application in diabetes mellitus, cardiovascular diseases, malignant tumor and trauma. Efficient techniques of non-invasively monitoring stem cell transplants will accelerate the development of stem cell therapies. This paper briefly reviews the clinical practice of stem cell, in addition, makes a review of monitoring methods including magnetic resonance and radionuclide imaging which have been used in stem cell therapy. (authors)

  19. Stem Cells

    Directory of Open Access Journals (Sweden)

    Madhukar Thakur

    2015-02-01

    Full Text Available Objective: The objective of this presentation is to create awareness of stem cell applications in the ISORBE community and to foster a strategy of how the ISORBE community can disseminate information and promote the use of radiolabeled stem cells in biomedical applications. Methods: The continued excitement in Stem Cells, in many branches of basic and applied biomedical science, stems from the remarkable ability of stem cells to divide and develop into different types of cells in the body. Often called as Magic Seeds, stem cells are produced in bone marrow and circulate in blood, albeit at a relatively low concentration. These virtues together with the ability of stem cells to grow in tissue culture have paved the way for their applications to generate new and healthy tissues and to replace diseased or injured human organs. Although possibilities of stem cell applications are many, much remains yet to be understood of these remarkable magic seeds. Conclusion: This presentation shall briefly cover the origin of stem cells, the pros and cons of their growth and division, their potential application, and shall outline some examples of the contributions of radiolabeled stem cells, in this rapidly growing branch of biomedical science

  20. The Effects of Oral Cryotherapy on Chemotherapy-Induced Oral Mucositis in Patients Undergoing Autologous Transplantation of Blood Stem Cells: A Clinical Trial

    Science.gov (United States)

    Askarifar, Marzieh; Lakdizaji, Sima; Ramzi, Mani; Rahmani, Azad; Jabbarzadeh, Faranak

    2016-01-01

    Background Oral mucositis is one of the irritating side effects of chemotherapy in patients undergoing bone marrow transplantation. However, up until now, the common methods of oral mucositis therapy have failed to show significant effects. Objectives The aim of this study was to investigate the effects of local cryotherapy on the intensity of chemotherapy-induced oral mucositis in autologous bone marrow transplantation patients. Patients and Methods In this single, blinded, randomized clinical trial, 29 patients undergoing stem cell transplantation in Iran were selected by convenience sampling, and randomly allocated to control (n = 13) and intervention groups (n = 16). In the intervention group, cryotherapy was applied, while the control group received a normal saline mouthwash. The severity of the mucositis and neutrophil rate were investigated in five periods, based on the world health organization (WHO) scales. The data were analyzed using descriptive statistics, the Mann-Whitney test, repeated measures analysis of variance (ANOVA), and linear regression. Results In both groups, the mucositis reached its peak intensity on the 7th day, and the least intensity was obtained on the 21st day. The neutrophil rate reached the minimum value on the 7th day, then increased up to the 21st day. The two groups showed no significant differences between the mucositis severity on the 14th and 21st days (P = 0.164), while the severity of the mucositis in the cryotherapy group was significantly less than that in the saline mouthwash group (1.81 groups. Conclusions The results showed that cryotherapy is more effective than the saline mouthwash in reducing the severity of mucositis. This method is recommended for the prevention of mucositis in bone marrow transplantation. PMID:27257512

  1. Embryonic Stem Cell Markers

    OpenAIRE

    Lan Ma; Liang Li; Wenxiu Zhao; Xiang Ji; Fangfang Zhang

    2012-01-01

    Embryonic stem cell (ESC) markers are molecules specifically expressed in ES cells. Understanding of the functions of these markers is critical for characterization and elucidation for the mechanism of ESC pluripotent maintenance and self-renewal, therefore helping to accelerate the clinical application of ES cells. Unfortunately, different cell types can share single or sometimes multiple markers; thus the main obstacle in the clinical application of ESC is to purify ES cells from other type...

  2. 关于干细胞临床产业化的一些思考%Several issues to consider before the industrialization of stem cell therapy and its clinical applications

    Institute of Scientific and Technical Information of China (English)

    邹曦; 陈海涛; 赵春林

    2011-01-01

    干细胞的基础研究和临床应用是近几年国内外的热点之一.但是因为没有产业化的明确途径,这个领域的产业化发展缓慢,很有可能像基因治疗和肿瘤疫苗的产业化一样无疾而终.本文探讨了干细胞治疗能够产业化之前需要解决的几个问题.从技术层面,我们比较了胚胎干细胞和成体干细胞,自体干细胞和异体干细胞的优缺点和国内外公司采取的一些途径.从政策方面,我们探讨了把干细胞治疗作为一种医疗技术还是一类医药产品的优缺点,比较了美国FDA和国内监管部门的相关政策,也提出了进一步的问题.最后,我们以美国FDA刚刚批准的Provenge为例,对细胞治疗和干细胞治疗的产业化提出了一些希望和想法.%Stem cell research and its clinical application are currently two of the hottest areas in research and clinical field.However, without a clear path for industrialization, its development is slow, and is likely to dwindle away as the clinical development of gene therapy and tumor vaccine.This article discussed several critical issues necessary before the wide clinical application of stem cell therapy.From the technical point, we compared embryonic and adult stem cell, and various approaches taken by international and domestic firms.From the policy stand point, we discussed the pros and cons when stem cell therapy is treated as a medical technology or a drug candidate, and the different policies taken by FDA from US and SFDA from China.Lastly, taking Provenge as an example, we provided our views and proposed a potential path for the industrialization of stem cell therapy and its clinical applications.

  3. Discuss of Ethics Problems of Stem Cell Regeneration Biology Research and Clinical Application%干细胞再生生物学研究及临床应用的道德伦理问题探讨

    Institute of Scientific and Technical Information of China (English)

    郭玲; William Isaacs; 徐学红; 李忠光; 杨荣华; 薛雅卓; 王春慧; Hiroshi Takeshima; MengMeng Xu; 刘万红; Jianjie Ma

    2016-01-01

    Stem cells have a pluripotency to develop to over 250 different cells composed of human body.This characteristic makes stem cell regeneration biology a most attention field of today’s life science research.USA and European countries have been enforced long-term limit on human Stem Cell ( SC) research.One of the reasons is that there is no clear definition of the ethics of stem cell research and application.In this study, the discussions focus on: (1 Ethical issues in stem cell science and the moral issues in scientific research on the prospects of stem cell re-generative biology application.(2) Cloning human embryos in order to solve ethical issues in stem cells clinical application such as materials shortage of organ transplantation, human stem cell source and whether the"life wastes"have the right to survive and so on.(3) New Internation-al ethical guidelines should be in opposition to cover future ethical issues generated from the most recent stem cell researches.To clarify relation-ship between stem cell research, clinical application and ethic morality as soon as possible, accelerate the establishment of relevant laws and regu-lations is undoubtedly the urgent need to protect stem cell regeneration biology research for the benefit of human health in the world.%干细胞具有分化为人类个体中250余种细胞的特性,该特性使再生生物学成为当今生命科学研究中最受瞩目的领域。美国和欧洲国家对干细胞研究的监管十分严格,其中一个重要原因是干细胞研究应用的道德伦理尚没有明确的界定。本文就以下几个问题进行讨论:干细胞科学研究中的伦理道德问题,干细胞再生生物学应用前景引发的科研道德问题;克隆人类胚胎以解决器官移植的材料短缺,人类干细胞来源和“生命废料”是否具有生存权等干细胞临床应用的伦理学问题;制定的国际伦理准则或法则应该对未来干细胞成果引发的伦理问

  4. Retention of long-term interim restorations with sodium fluoride enriched interim cement

    Science.gov (United States)

    Strash, Carolyn

    Purpose: Interim fixed dental prostheses, or "provisional restorations", are fabricated to restore teeth when definitive prostheses are made indirectly. Patients undergoing extensive prosthodontic treatment frequently require provisionalization for several months or years. The ideal interim cement would retain the restoration for as long as needed and still allow for ease of removal. It would also avoid recurrent caries by preventing demineralization of tooth structure. This study aims to determine if adding sodium fluoride varnish to interim cement may assist in the retention of interim restorations. Materials and methods: stainless steel dies representing a crown preparation were fabricated. Provisional crowns were milled for the dies using CAD/CAM technology. Crowns were provisionally cemented onto the dies using TempBond NE and NexTemp provisional cements as well as a mixture of TempBond NE and Duraphat fluoride varnish. Samples were stored for 24h then tested or thermocycled for 2500 or 5000 cycles before being tested. Retentive strength of each cement was recorded using a universal testing machine. Results: TempBond NE and NexTemp cements performed similarly when tested after 24h. The addition of Duraphat significantly decreased the retention when added to TempBond NE. NexTemp cement had high variability in retention over all tested time periods. Thermocycling for 2500 and 5000 cycles significantly decreased the retention of all cements. Conclusions: The addition of Duraphat fluoride varnish significantly decreased the retention of TempBond NE and is therefore not recommended for clinical use. Thermocycling significantly reduced the retention of TempBond NE and NexTemp. This may suggest that use of these cements for three months, as simulated in this study, is not recommended.

  5. Treatment of a Vertical Root Fracture Using Dual-Curing Resin Cement: A Case Report

    Directory of Open Access Journals (Sweden)

    Nima Moradi Majd

    2012-01-01

    Full Text Available Introduction. Vertical root fracture (VRF is one of the most frustrating complications of root canal treatment. The prognosis of the root with VRF is poor therefore tooth extraction and root amputation are usually the only treatment options. However, bonding of the fracture line with adhesive resin cement during the intentional replantation procedure was recently suggested as an alternative to tooth extraction. Methods. A vertically fractured left maxillary incisor was carefully extracted, fracture line was treated with adhesive resin cement, a retrograde cavity was produced and filled with calcium-enriched mixture (CEM cement, and tooth was replanted. Results. After 12 months the tooth was asymptomatic. The size of periapical radiolucency was noticeably reduced and there was no clinical sign of ankylosis. Conclusion. Using adhesive resin cement to bond the fracture lines extraorally in roots with VRF and intentional replantation of the reconstructed teeth could be considered as an alternative to tooth extraction, especially for anterior teeth.

  6. Carbonation on ternary cement systems

    OpenAIRE

    Martínez Ramírez, Sagrario; Fernández Carrasco, Lucía

    2012-01-01

    The main hydration reaction product in the ternary system fly ash, calcium sulphate and calcium aluminate cement (40/20/40) at 20°C is a hydrated calcium sulfoaluminate compound, an AFt phase slightly different from “traditional ettringite”. The carbonation of ettringite develops gypsum but in this case rapidcreekite is formed. For the first time it has been observed that carbonation of the mentioned calcium sulfoaluminate compound (AFt), an hydrated calcium sulphate carbonated phase (Ca2(SO4...

  7. WHITE CEMENT IN SUSTAINABLE DEVELOPMENT

    OpenAIRE

    Y.C.P RAMANA BABU; B.SAI DOONDI; N. M .V .VAMSI KRISHNA; K.Prasanthi

    2013-01-01

    India is one among the fast developing countries in the world in the areas of Infrastructure. Now a day, Carbon monoxide (CO) and carbon dioxide (CO2) are the temporary atmospheric pollutants in the environment chiefly emitted from the fuel burning vehicles and street lights which lead to global warming and pose a major threat tothe survival and sustainable development. This paper deals with the principal purpose of use of white cement in pavement design which will take care of the Green hous...

  8. ROTARY SCREW SYSTEMS IN CEMENT

    OpenAIRE

    Taratuta V. D.; Belokur K. A.; Serga G. V.

    2016-01-01

    The article presents results of research of rotary-screw systems in relation to the creation of rotary kilns for the annealing of-cuttings in the preparation of cement clinker. Using the proposed design, in comparison with known designs of similar purpose, it significantly improves performance, reduces size and power consumption through the use of rotary screw systems in the form of screw rotors and drums made hollow with sidewalls assembled from separate strips or plates of different geometr...

  9. WHITE CEMENT IN SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Y.C.P RAMANA BABU

    2013-04-01

    Full Text Available India is one among the fast developing countries in the world in the areas of Infrastructure. Now a day, Carbon monoxide (CO and carbon dioxide (CO2 are the temporary atmospheric pollutants in the environment chiefly emitted from the fuel burning vehicles and street lights which lead to global warming and pose a major threat tothe survival and sustainable development. This paper deals with the principal purpose of use of white cement in pavement design which will take care of the Green house gases (i.e., CO and CO2 and also saves lot of money in the long run process. A small amount of these gases in environment can cause major problems over time. Use of white cement in composite pavement design where there is heavy traffic loads are acting as well as number of vehicles are more such as junctions, bus stops, check posts etc., can perform better and acts asenvironment friendly. Its light colour reflects more than bituminous pavement so that it can be easily identified and avoid accidents to some extent. White cement helps to lower the average bus stop, junction temperature providing comfort to the people because it has high solar reflectance there by reducing “urban heat island” effect. In addition to this it has some more advantages which increase the sustainability, durability and workability of the pavements.

  10. Avaliação clínica de um cimento de ionômero de vidro utilizado como selante oclusal: a clinical evaluation Use of a glass ionomer cement as an occlusal sealant

    Directory of Open Access Journals (Sweden)

    Pedro Cheque BERNARDO

    2000-03-01

    Full Text Available Sabendo-se do papel do flúor na Odontologia Preventiva, cada vez mais procuram-se materiais restauradores com propriedades de liberação deste íon. Dentre os selantes oclusais, grande expectativa existe em relação aos cimentos de ionômero de vidro, particularmente os fotopolimerizáveis, por possuírem melhores propriedades. O objetivo deste trabalho foi testar um destes cimentos, Vitremer (3M, aplicado em: combinação ou não com um adesivo. A avaliação foi realizada em 159 dentes, 6 e 12 meses após a aplicação do selante, observando-se sua retenção e a presença ou ausência de lesão de cárie. Concluiu-se que a técnica modificada, com adesivo, propiciou significativamente melhor retenção após 6 e 12 meses que a técnica convencional, não havendo diferença entre molares e pré-molares. Apenas um dente do grupo sem adesivo desenvolveu lesão de cárie após a perda do material.Since fluoride’s properties are widely known in the field of Preventive Dentistry, fluoride-releasing materials have been extensively investigated. Among the occlusal sealants, there is great expectation regarding the results that can be achieved with light-curing glass-ionomer cements due to their excellent properties. The aim of this study was to assess the use of one of these cements, Vitremer (3M as an occlusal sealant. The material was applied using two different techniques; either associated or not with an adhesive system. After 6 and 12 months of observation, an evaluation was performed in 159 teeth to verify its retention as well as the presence of caries lesions. The technique that included the adhesive system showed better retention than the conventional one. Total retention was 84.9% for the experimental technique and 37.2% for the conventional technique after 12 months. There was no difference between bicuspids and molars regarding retention. Caries lesion was observed in a single tooth, for which a total loss of material was observed

  11. Cement replacement materials. Properties, durability, sustainability

    Energy Technology Data Exchange (ETDEWEB)

    Ramezanianpour, Ali Akbar [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Concrete Technology Center

    2014-04-01

    The aim of this book is to present the latest findings in the properties and application of Supplementary Cementing Materials and blended cements currently used in the world in concrete. Sustainability is an important issue all over the world. Carbon dioxide emission has been a serious problem in the world due to the greenhouse effect. Today many countries agreed to reduce the emission of CO2. Many phases of cement and concrete technology can affect sustainability. Cement and concrete industry is responsible for the production of 7% carbon dioxide of the total world CO2 emission. The use of supplementary cementing materials (SCM), design of concrete mixtures with optimum content of cement and enhancement of concrete durability are the main issues towards sustainability in concrete industry.

  12. Scanning electron microscopy analysis of dental cements

    Directory of Open Access Journals (Sweden)

    Radosavljević Radivoje D.

    2009-01-01

    Full Text Available The aim of this study was to compare in vitro the characteristics of different types of luting cements (zinc phosphate, glass-ionomer and resin based composite cement using scanning electron microscopy (SEM analysis and microleakage for the quality range of materials. Dental cements were mixed in accordance with the manufacturer's instructions and formed with posts in dental root canals of extracted teeth. The quality of cement was determined by SEM observation on horizontal sectioned roots with fixed posts according to specific pore and marginal gap diameter. The microleakage was measured on specimens immersed in Lofler (methylene blue solution. The mean values of the maximal diameter of pores, marginal gaps and microleakage of conventional cements are remarkably larger in comparison with composite luting agents. In conclusion, the quality and efficiency of composite luting agents in comparison with conventional cements are more successful in protecting the interior of tooth from penetration of oral fluids, bacteria and bacterial toxins into unprotected dentine.

  13. The effect of oligo(trimethylene carbonate) addition on the stiffness of acrylic bone cement.

    Science.gov (United States)

    Persson, Cecilia; López, Alejandro; Fathali, Hoda; Hoess, Andreas; Rojas, Ramiro; Ott, Marjam Karlsson; Hilborn, Jöns; Engqvist, Håkan

    2016-01-01

    With the increasing elderly population an increase in the number of bony fractures associated to age-related diseases such as osteoporosis also follows. The relatively high stiffness of the acrylic bone cements used in these patients has been suggested to give raise to a suboptimal load distribution surrounding the cement in vivo, and hence contribute to clinical complications, such as additional fractures. The aim of this study was to develop a low-modulus bone cement, based on currently used, commercially available poly(methyl methacrylate) (PMMA) cements for vertebroplasty. To this end, acrylate end-functionalized oligo(trimethylene carbonate) (oTMC) was incorporated into the cements, and the resulting compressive mechanical properties were evaluated, as well as the cytotoxic and handling properties of selected formulations. Sixteen wt%oTMC was needed in the vertebroplastic cement Osteopal V to achieve an elastic modulus of 1063 MPa (SD 74), which gave a corresponding compressive strength of 46.1 MPa (SD 1.9). Cement extracts taken at 1 and 12 hours gave a reduced MG-63 cell viability in most cases, while extracts taken at 24 hours had no significant effect on cell behavior. The modification also gave an increase in setting time, from 14.7 min (SD 1.7) to 18.0 min (SD 0.9), and a decrease in maximum polymerization temperature, from 41.5°C (SD 3.4) to 30.7°C (SD 1.4). While further evaluation of other relevant properties, such as injectability and in vivo biocompatibility, remains to be done, the results presented herein are promising in terms of approaching clinically applicable bone cements with a lower stiffness. PMID:26727581

  14. Safety Profile, Feasibility and Early Clinical Outcome of Cotransplantation of Olfactory Mucosa and Bone Marrow Stem Cells in Chronic Spinal Cord Injury Patients

    OpenAIRE

    Goni, Vijay G.; Chhabra, Rajesh; Gupta, Ashok; Marwaha, Neelam; Dhillon, Mandeep S; Pebam, Sudesh; Gopinathan, Nirmal Raj; Bangalore Kantharajanna, Shashidhar

    2014-01-01

    Study Design Prospective case series. Purpose To study the safety and feasibility of cotransplantation of bone marrow stem cells and autologous olfactory mucosa in chronic spinal cord injury. Overview of Literature Stem cell therapies are a novel method in the attempt to restitute heavily damaged tissues. We discuss our experience with this modality in postspinal cord injury paraplegics. Methods The study includes 9 dorsal spine injury patients with American Spinal Injury Association (ASIA) I...

  15. New Therapy of Skin Repair Combining Adipose-Derived Mesenchymal Stem Cells with Sodium Carboxymethylcellulose Scaffold in a Pre-Clinical Rat Model

    OpenAIRE

    Cristiano Rodrigues; de Assis, Adriano M.; Moura, Dinara J.; Graziele Halmenschlager; Jenifer Saffi; Léder Leal Xavier; Marilda da Cruz Fernandes; Márcia Rosângela Wink

    2014-01-01

    Lesions with great loss of skin and extensive burns are usually treated with heterologous skin grafts, which may lead rejection. Cell therapy with mesenchymal stem cells is arising as a new proposal to accelerate the healing process. We tested a new therapy consisting of sodium carboxymethylcellulose (CMC) as a biomaterial, in combination with adipose-derived stem cells (ADSCs), to treat skin lesions in an in vivo rat model. This biomaterial did not affect membrane viability and induced a sma...

  16. Clinical outcomes of xeno-free expansion and transplantation of autologous ocular surface epithelial stem cells via contact lens delivery: a prospective case series

    OpenAIRE

    Bobba, Samantha; Chow, Sharron; Watson, Stephanie; Di Girolamo, Nick

    2015-01-01

    Introduction Depletion of limbal stem cells leads to a debilitating condition known as limbal stem cell deficiency, characterised by impaired corneal wound healing and poor vision. The aim of this study was to determine whether delivering progenitor cells on a contact lens is a viable and effective alternative to current transplantation techniques, which are complicated by biological and xenogeneic materials. Methods Sixteen eyes of 16 patients who had total (n = 14) and partial (n = 2) limba...

  17. Sustainable Development of the Cement Industry and Blended Cements to Meet Ecological Challenges

    OpenAIRE

    Konstantin Sobolev

    2003-01-01

    The world production of cement has greatly increased in the past 10 years. This trend is the most significant factor affecting technological development and the updating of manufacturing facilities in the cement industry. Existing technology for the production of cement clinker is ecologically damaging; it consumes much energy and natural resources and also emits pollutants. A new approach to the production of blended or high-volume mineral additive (HVMA) cement helps to improve its ecologi...

  18. Global Cement Industry: Competitive and Institutional Dimensions

    OpenAIRE

    Selim, Tarek; Salem, Ahmed

    2010-01-01

    The cement industry is a capital intensive, energy consuming, and vital industry for sustaining infrastructure of nations. The international cement market –while constituting a small share of world industry output—has been growing at an increasing rate relative to local production in recent years. Attempts to protect the environment in developed countries –especially Europe—have caused cement production plants to shift to countries with less stringent environmental regulations. Along with con...

  19. Characterization of cement composites with mineral additives

    OpenAIRE

    Korat, Lidija

    2015-01-01

    Doctoral dissertation is aimed at characterizing cement composites with mineral additives representing the industrial waste material (fly ash, granulated blast furnace slag and biomass fly ash). Their usage can replace high cement shares in individual cases and is, however, favourable due to the production costs reduction and environment burden decrease, including the decreased emission of greenhouse gases as well as lower energy use. Cement composites (in fresh or hardened state)...

  20. Premixed calcium silicate cement for endodontic applications

    OpenAIRE

    Persson, Cecilia; Engqvist, Håkan

    2011-01-01

    Calcium silicate-based materials (also called MTA) are increasingly being used in endodontic applications. However, the handling properties of MTA are not optimal when it comes to injectability and cohesion. Premixing the cements using glycerol avoids these issues. However, there is a lack of data on the effect of common cement variables on important properties of premixed cements for endodontic applications. In this study, the effects of liquid-to-powder ratio, amount of radiopacifier and am...

  1. Water dynamics in glass ionomer cements

    Science.gov (United States)

    Berg, M. C.; Jacobsen, J.; Momsen, N. C. R.; Benetti, A. R.; Telling, M. T. F.; Seydel, T.; Bordallo, H. N.

    2016-07-01

    Glass ionomer cements (GIC) are an alternative for preventive dentistry. However, these dental cements are complex systems where important motions related to the different states of the hydrogen atoms evolve in a confined porous structure. In this paper, we studied the water dynamics of two different liquids used to prepare either conventional or resin-modified glass ionomer cement. By combining thermal analysis with neutron scattering data we were able to relate the water structure in the liquids to the materials properties.

  2. Retention of Root Canal Posts: Effect of Cement Film Thickness, Luting Cement, and Post Pretreatment.

    Science.gov (United States)

    Sahafi, A; Benetti, A R; Flury, S; Peutzfeldt, A

    2015-01-01

    The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc] and a self-etch adhesive resin cement [Panavia F2.0]) were used. After removal of the crowns of 360 extracted premolars, canines, or incisors, the root canals were prepared with a parallel-sided drill system to three different final diameters. Half the posts did not receive any pretreatment. The other half received tribochemical silicate coating according to the manufacturer's instructions. Posts were then luted in the prepared root canals (n=30 per group). Following water storage at 37°C for seven days, retention of the posts was determined by the pull-out method. Irrespective of the luting cement, pretreatment with tribochemical silicate coating significantly increased retention of the posts. Increased cement film thickness resulted in decreased retention of untreated posts and of pretreated posts luted with zinc phosphate cement. Increased cement film thickness had no influence on retention of pretreated posts luted with resin cement. Thus, retention of the posts was influenced by the type of luting cement, by the cement film thickness, and by the post pretreatment. PMID:25764045

  3. The influence of ultrasound on removal of prefabricated metal post cemented with different resin cements

    Directory of Open Access Journals (Sweden)

    Atiyeh Feiz

    2013-01-01

    Conclusion: Ultrasonic energy did not decrease the retention of posts cemented with Panavia or Maxcem Elite cements. Furthermore, it seems that there is no significant difference between removal force of self-etch (Panavia and the self-etch self-adhesive (Maxcem Elite resin cements.

  4. Case Study of the California Cement Industry

    OpenAIRE

    Coito, Fred; Powell, Frank; Worrell, Ernst; Price, Lynn; Friedmann, Rafael

    2005-01-01

    California is the largest cement producing state in the U.S., accounting for between 10 percent and 15 percent of U.S. cement production and cement industry employment. The cement industry in California consists of 31 sites that consume large amounts of energy, annually: 1,600 GWh of electricity, 22 million therms of natural gas, 2.3 million tons of coal, 0.25 tons of coke, and smaller amounts of waste materials, including tires. The case study summarized in this paper focused on providi...

  5. Immobilisation of radwaste in cement based matrices

    International Nuclear Information System (INIS)

    The solubilities and influence on cement pH are reported for calcium aluminate and aluminosulphate hydrates. The solubility of Ca(OH)2 is reported to 700 bars. Polymerization of C-S-H is investigated by NMR. Specific interactions of U6+ and iodine (I-, IO3-) with cement components are described. The impact of radiation on cements and the influence of higher temperature are documented. The role of dissolved Ca and CO2 in groundwaters as dissolution media for cements are reported. (author)

  6. Concise Review: Stem Cell Therapy for Muscular Dystrophies

    OpenAIRE

    Wilschut, Karlijn J.; Ling, Vivian B.; Bernstein, Harold S.

    2012-01-01

    Stem cell therapy holds promise as a treatment for muscular dystrophy by providing cells that can both deliver functional muscle proteins and replenish the stem cell pool. This article reviews the current state of research on myogenic stem cells and identifies the important challenges that must be addressed as stem cell therapy is brought to the clinic.

  7. What are Stem Cells?

    Directory of Open Access Journals (Sweden)

    Ahmadshah Farhat

    2014-05-01

    Full Text Available   Stem cells are undifferentiated self regenerating multi potential cells. There are three types of stem cells categories by the ability to form after cells and correlated with the body’s development process. Totipotent: these stem cells can form an entire organism such as fertilized egg. Ploripotent: ploripotent cells are those that can form any cell in the body but cannot form an entire organism such as developing embryo’s totipotent cells become ploripotent  Multipotent: Multi potent stem cells are those that can only form specific cells in the body such as blood cells based. Based on the sources of stem cells we have three types of these cells: Autologous: Sources of the patient own cells are (Autologous either the cells from patient own body or his or her cord blood. For this type of transplant the physician now usually collects the periphery rather than morrow because the procedure is easier on like a bane morrow harvest it take place outside of an operating room, and the patient does not to be under general unsetting . Allogenic: Sources of stem cells from another donore are primarily relatives (familial allogenic or completely unrelated donors. Xenogenic: In these stem cells from different species are transplanted e .g striatal porcine fetal mesan cephalic (FVM xenotransplants for Parkinson’s disease. On sites of isolation such as embryo, umbilical cord and other body tissues stem cells are named embnyonic, cord blood, and adult stem cells. The scope of results and clinical application of stem cells are such as: Neurodegenerative conditions (MS,ALS, Parkinson’s, Stroke, Ocular disorders- Glaucoma, retinitis Pigmentosa (RP, Auto Immune Conditions (Lupus, MS,R. arthritis, Diabetes, etc, Viral Conditions (Hepatitis C and AIDS, Heart Disease, Adrenal Disorders, Injury(Nerve, Brain, etc, Anti aging (hair, skin, weight control, overall well being/preventive, Emotional disorders, Organ / Tissue Cancers, Blood cancers, Blood diseases

  8. Acoustic evaluation of cementing quality using obliquely incident ultrasonic signals

    Institute of Scientific and Technical Information of China (English)

    Duan Wen-Xing; Qiao Wen-Xiao; Che Xiao-Hua; Xie Hui

    2014-01-01

    Ultrasonic cement bond logging is a widely used method for evaluating cementing quality. Conventional ultrasonic cement bond logging uses vertical incidence and cannot accurately evaluate lightweight cement bonding. Oblique incidence is a new technology for evaluating cement quality with improved accuracy for lightweight cements. In this study, we simulated models of acoustic impedance of cement and cementing quality using ultrasonic oblique incidence, and we obtained the relation between cementing quality, acoustic impedance of cement, and the acoustic attenuation coeffi cient of the A0-mode and S0-mode Lamb waves. Then, we simulated models of different cement thickness and we obtained the relation between cement thickness and the time difference of the arrival between the A0 and A0′ modes.

  9. Becoming a Blood Stem Cell Donor

    Medline Plus

    Full Text Available ... Institutes of Health Clinical Center in Bethesda, MD. Bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT) ... Medicine Clinics 225,676 views 6:18 Alicia's bone marrow donation - Duration: 8:33. ... Peripheral Blood Stem Cell Transplant - Duration: 15:50. Dartmouth-Hitchcock 2,764 views ...

  10. Design and manufacture of Portland cement Application of statistical analysis

    OpenAIRE

    Svinning, Ketil

    2011-01-01

    The purpose of the work is to enable design and manufacture of cement with emphasis on the quality and the properties of cement. Data used in the design and manufacture were collected from predictions of properties and characteristics of cement. The properties of cement were predicted from its characteristics and from the production conditions in cement kiln and mill. The cement characteristics were in some investigations predicted from the production conditions. The design was based on sensi...

  11. The effect of unsaturated fatty acid and triglyceride oil addition on the mechanical and antibacterial properties of acrylic bone cements.

    Science.gov (United States)

    Persson, Cecilia; Robert, Elise; Carlsson, Elin; Robo, Céline; López, Alejandro; Godoy-Gallardo, Maria; Ginebra, Maria-Pau; Engqvist, Håkan

    2015-09-01

    Acrylic bone cements have an elastic modulus several times higher than the surrounding trabecular bone. This has been hypothesized to contribute to certain clinical complications. There are indications that the addition of specific fatty acids and triglyceride oils may reduce the elastic modulus of these types of cements. Some of these additives also appear to have inherent antibiotic properties, although this has never been evaluated in bone cements. In this study, several types of fatty acids and triglyceride oils were evaluated for use in acrylic bone cements. Their mechanical properties were evaluated under uniaxial compression testing and selected cements were then further characterized in terms of microstructure, handling and antibacterial properties using scanning electron microscopy, polymerization temperature measurements, agar diffusion tests and bactericidal activity assays of cement extracts. It was found that any of the evaluated fatty acids or triglyceride oils could be used to tailor the stiffness of acrylic bone cements, although at varying concentrations, which also depended on the type of commercial base cement used. In particular, the addition of very small amounts of linoleic acid (agar diffusion test as well as demonstrating 100% bactericidal activity against the same strain. PMID:25876889

  12. Effects of the iron oxide nanoparticle Molday ION Rhodamine B on the viability and regenerative function of neural stem cells: relevance to clinical translation

    Science.gov (United States)

    Umashankar, Abhishek; Corenblum, Mandi J; Ray, Sneha; Valdez, Michel; Yoshimaru, Eriko S; Trouard, Theodore P; Madhavan, Lalitha

    2016-01-01

    An essential component of developing successful neural stem cell (NSC)-based therapies involves the establishment of methodologies to noninvasively monitor grafted NSCs within brain tissues in real time. In this context, ex vivo labeling with ultrasmall superparamagnetic iron oxide (USPIO) particles has been shown to enable efficient tracking of transplanted NSCs via magnetic resonance imaging (MRI). However, whether and how USPIO labeling affects the intrinsic biology of NSCs is not thoroughly understood, and remains an active area of investigation. Here, we perform a comprehensive examination of rat NSC survival and regenerative function upon labeling with the USPIO, Molday ION Rhodamine B (MIRB), which allows for dual magnetic resonance and optical imaging. After optimization of labeling efficiency, two specific doses of MIRB (20 and 50 μg/mL) were chosen and were followed for the rest of the study. We observed that both MIRB doses supported the robust detection of NSCs, over an extended period of time in vitro and in vivo after transplantation into the striata of host rats, using MRI and post hoc fluorescence imaging. Both in culture and after neural transplantation, the higher 50 μg/mL MIRB dose significantly reduced the survival, proliferation, and differentiation rate of the NSCs. Interestingly, although the lower 20 μg/mL MIRB labeling did not produce overtly negative effects, it increased the proliferation and glial differentiation of the NSCs. Additionally, application of this dose also changed the morphological characteristics of neurons and glia produced after NSC differentiation. Importantly, the transplantation of NSCs labeled with either of the two MIRB doses upregulated the immune response in recipient animals. In particular, in animals receiving the 50 μg/mL MIRB-labeled NSCs, this immune response consisted of an increased number of CD68+-activated microglia, which appeared to have phagocytosed MIRB particles and cells contributing to an

  13. Microscopic evaluation regarding time behavior of orthodontic cements used for disjunctor cementing

    Directory of Open Access Journals (Sweden)

    Ruxandra Bartok

    2015-11-01

    Full Text Available In order to fulfill their function, orthodontic devices must be cemented on teeth using orthodontic rings. The retention of the orthodontic ring is influenced mainly by the type of dental-ring adhesion. This study was initiated to determine possible microleakage events while using zinc phosphate cement Adhesor (Spofa Dental, conventional glass ionomer Ketac Cem (3M ESPE and Fuji Ortho (GC and a compomer Transbond Plus (3M Unitek. The results of the study are consistent with those reported in the literature reference, the compomer is the preferred adhesive material for cementing the orthodontic rings, compared to conventional glass ionomer cements and zinc-phosphate cement.

  14. Learn About Stem Cells

    Science.gov (United States)

    ... PDF) Download an introduction to stem cells and stem cell research. Stem Cell Glossary Stem cell terms to know. ... ISSCR Get Involved Media © 2015 International Society for Stem Cell Research Terms of Use Disclaimer Privacy Policy

  15. Stem Properties of Autobacteria

    Directory of Open Access Journals (Sweden)

    Boris A. Berdichevskyy

    2014-03-01

    Full Text Available This paper discusses the stem properties of the autobacteria as part of the activation syndrome and persistence of the endogenous microflora in the adaptation process of the macroorganism to stress, as well as the ability of the bacteria to stimulate the cells of the macroorganism to manifest stem properties. The essence of this syndrome involves testing the tissue with the autobacteria of their "host" body to identify the foci of cellular insolvency with the subsequent inclusion of the autostrains in the implementation phase of the catabolic and anabolic inflammations. Considering the genetic tropism of the microbes to the organ-specific tissue of the area affected, the existence of the stem properties of the autobacteria is assumed to be realized in the process of reparative regeneration. The great clinical significance of further study of this phenomenon is not excluded.

  16. Comparative study of nanomechanical properties of cements used in teeth restoration

    International Nuclear Information System (INIS)

    The discipline of dental science includes the diagnosis of disease in the mouth and teeth, its manifestations and the procedures involved in the restoration of their integrity and function. Restoration of lost tooth structure with suitable materials plays an integral part in the successful rehabilitation of oral tissues. Several factors influence the performance of dental restorations. These factors include the type of cement used to bond crown restoration to prepared teeth. The nanoindentation method was used to explore the mechanical properties of different types of resin cement polymerized using different techniques. A Nano Indenter XP (from MTS Nano Instruments, USA) was used for the experimental tests. A sample of 40 extracted human teeth were restored using two different resin cements: Variolink II (Ivoclar Vivadent, Liechtenstein) and Venus A2 (Heraeus Kulzer, Germany). Both resin cements are light-cured and one of them is self-cured so that the degree of polymerization would be higher. The data obtained for nanohardness and the Young's modulus were analysed using ANOVA to evaluate the influence of different factors (the resin cement and polymerization technique used, the position on the tooth-restoration interface) and to determine the best performance for restoration. The results obtained could give a useful indication of the choice of cementation technique and of the materials used for the restoration of lost tooth structure in different clinical cases

  17. Comparative study of nanomechanical properties of cements used in teeth restoration

    Science.gov (United States)

    Peluccio, M. S.; Bignardi, C.; Lombardo, S.; Montevecchi, F. M.; Carossa, S.

    2007-10-01

    The discipline of dental science includes the diagnosis of disease in the mouth and teeth, its manifestations and the procedures involved in the restoration of their integrity and function. Restoration of lost tooth structure with suitable materials plays an integral part in the successful rehabilitation of oral tissues. Several factors influence the performance of dental restorations. These factors include the type of cement used to bond crown restoration to prepared teeth. The nanoindentation method was used to explore the mechanical properties of different types of resin cement polymerized using different techniques. A Nano Indenter XP (from MTS Nano Instruments, USA) was used for the experimental tests. A sample of 40 extracted human teeth were restored using two different resin cements: Variolink II (Ivoclar Vivadent, Liechtenstein) and Venus A2 (Heraeus Kulzer, Germany). Both resin cements are light-cured and one of them is self-cured so that the degree of polymerization would be higher. The data obtained for nanohardness and the Young's modulus were analysed using ANOVA to evaluate the influence of different factors (the resin cement and polymerization technique used, the position on the tooth-restoration interface) and to determine the best performance for restoration. The results obtained could give a useful indication of the choice of cementation technique and of the materials used for the restoration of lost tooth structure in different clinical cases.

  18. Comparative study of nanomechanical properties of cements used in teeth restoration

    Energy Technology Data Exchange (ETDEWEB)

    Peluccio, M S [Department of Mechanics, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Bignardi, C [Department of Mechanics, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Lombardo, S [Department of Prosthodontics, University of Torino, C.so Bramante 88/90, 10126 Turin (Italy); Montevecchi, F M [Department of Mechanics, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Carossa, S [Department of Prosthodontics, University of Torino, C.so Bramante 88/90, 10126 Turin (Italy)

    2007-10-03

    The discipline of dental science includes the diagnosis of disease in the mouth and teeth, its manifestations and the procedures involved in the restoration of their integrity and function. Restoration of lost tooth structure with suitable materials plays an integral part in the successful rehabilitation of oral tissues. Several factors influence the performance of dental restorations. These factors include the type of cement used to bond crown restoration to prepared teeth. The nanoindentation method was used to explore the mechanical properties of different types of resin cement polymerized using different techniques. A Nano Indenter XP (from MTS Nano Instruments, USA) was used for the experimental tests. A sample of 40 extracted human teeth were restored using two different resin cements: Variolink II (Ivoclar Vivadent, Liechtenstein) and Venus A2 (Heraeus Kulzer, Germany). Both resin cements are light-cured and one of them is self-cured so that the degree of polymerization would be higher. The data obtained for nanohardness and the Young's modulus were analysed using ANOVA to evaluate the influence of different factors (the resin cement and polymerization technique used, the position on the tooth-restoration interface) and to determine the best performance for restoration. The results obtained could give a useful indication of the choice of cementation technique and of the materials used for the restoration of lost tooth structure in different clinical cases.

  19. The influence of cement type and temperature on chloride binding in cement paste

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Korzen, Migge Sofie Hoffmann; Skibsted, Jørgen

    1998-01-01

    This paper describes effects of cement type and temperature on chloride binding in cement paste, which is an important subject in relation to life-time modelling of reinforced concrete structures. The influence of cement type on chloride binding is investigated by substituting cement with pure...... cement clinker. Both theoretical considerations and experimental data for chloride binding in cement pastes are presented. A physico-chemically based model to describe the influence of temperature on physical binding of chloride is presented. Solid-state 27Al and 29Si magic-angle spinning (MAS) nuclear...... magnetic resonance (NMR) spectroscopy has been used for quantification of the anhydrous and hydrated aluminate and silicate phases in the chloride exposed cement pastes. The 27Al isotropic chemical shift and nuclear quadrupole coupling is reported for a synthetic sample of Friedel's salt, Ca2Al(OH)6Cl×2H2O....

  20. Cements in radioactive waste management. Characterization requirements of cement products for acceptance and quality assurance purposes

    International Nuclear Information System (INIS)

    Cementitious materials are used as immobilizing matrices for low (LLW) and medium-level wastes (MLW) and are also components of the construction materials in the secondary barriers and the repositories. This report has concerned itself with a critical assessment of the quality assurance aspects of the immobilization and disposal of MLW and LLW cemented wastes. This report has collated the existing knowledge of the use and potential of cementitious materials in radioactive waste immobilization and highlighted the physico-chemical parameters. Subject areas include an assessment of immobilization objectives and cement as a durable material, waste stream and matrix characterization, quality assurance concepts, nature of cement-based systems, chemistry and modelling of cement hydration, role and effect of blending agents, radwaste-cement interaction, assessment of durability, degradative and radiolytic processes in cements and the behaviour of cement-based matrices and their near-field interactions with the environment and the repository conditions

  1. Copper Slag Blended Cement: An Environmental Sustainable Approach for Cement Industry in India

    Directory of Open Access Journals (Sweden)

    Jagmeet Singh

    2016-04-01

    Full Text Available Indian cement industry is facing environmental issue of emission of carbon dioxide (CO2, a greenhouse gas. Blended cements including supplementary cementitious materials are substitute of Portland cement to reduce CO2 emission. The present paper investigates theappropriateness of copper slag (CS as supplementary cementitious material. Strength properties and hydration of mixes were determined at different replacement levels of CS with cement. Compressive, flexural and tensile strength of each mix was found out at different curing periods. The hydration of cement was investigated through X-ray diffraction (XRD. The strength test results showed that substitution of up to 20% of CS can significantly replace Portland cement.XRD test results were corresponding to strength test results. The present study encourages the utilization of CS as supplementary cementitious material to make economical and environmentally sustainable blended cement

  2. 21 CFR 872.3275 - Dental cement.

    Science.gov (United States)

    2010-04-01

    ... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification. Zinc oxide-eugenol is a device composed of zinc oxide-eugenol intended to serve as a temporary tooth... chapter subject to § 872.9. (b) Dental cement other than zinc oxide-eugenol—(1) Identification....

  3. A Pause for China's Cement Industry

    Institute of Scientific and Technical Information of China (English)

    Li Zhen

    2009-01-01

    @@ Cement industry suffers excess productionWith the advent of global financial crisis,the Chinese government has laid out a stimulus package on infrastructure construction.Driven by the investment spree,China's cement makers are flocking to expand output capacity,which is now leading the industry into a much-higher-thanneeded state.

  4. Pre-portland cements and geopolymers

    Czech Academy of Sciences Publication Activity Database

    Hanzlíček, Tomáš; Perná, Ivana; Ertl, Z.; Miller, S.M.

    2012-01-01

    Roč. 9, č. 1 (2012), s. 57-62. ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30460519 Keywords : caementum * cement itious * calcareous cement Subject RIV: JN - Civil Engineering Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/materialy/acta_content/2012_01/5_Hanzlicek.pdf

  5. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.; Glasser, Fred P.

    1999-01-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature), The measurements are...

  6. Synthesis of pure Portland cement phases

    DEFF Research Database (Denmark)

    Wesselsky, Andreas; Jensen, Ole Mejlhede

    2009-01-01

    Pure phases commonly found in Portland cement clinkers are often used to test cement hydration behaviour in simplified experimental conditions. The synthesis of these phases is covered in this paper, starting with a description of phase relations and possible polymorphs of the four main phases in...

  7. Investigation of a Hardened Cement Paste Grout

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro; Sørensen, Eigil Verner

    This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S.......This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S....

  8. A note on cement in asteroids

    CERN Document Server

    Bilalbegovic, G

    2016-01-01

    Cement mineral tobermorite was formed in hydrothermal experiments on alternation of calcium-aluminum-rich inclusions (CAIs) in carbonaceous chondrite meteorites. Unidentified bands at 14 microns were measured for CAIs and the matrix of the Allende meteorite sample, as well as for Hektor and Agamemnon asteroids. The presence of cement nanoparticles may explain the feature at 14 microns.

  9. Cemented versus uncemented fixation in total hip replacement: a systematic review and meta-analysis of randomized controlled trials.

    LENUS (Irish Health Repository)

    Abdulkarim, Ali

    2013-02-22

    The optimal method of fixation for primary total hip replacements (THR), particularly fixation with or without the use of cement is still controversial. In a systematic review and metaanalysis of all randomized controlled trials comparing cemented versus uncemented THRS available in the published literature, we found that there is no significant difference between cemented and uncemented THRs in terms of implant survival as measured by the revision rate. Better short-term clinical outcome, particularly an improved pain score can be obtained with cemented fixation. However, the results are unclear for the long-term clinical and functional outcome between the two groups. No difference was evident in the mortality and the post operative complication rate. On the other hand, the radiographic findings were variable and do not seem to correlate with clinical findings as differences in the surgical technique and prosthesis design might be associated with the incidence of osteolysis. We concluded in our review that cemented THR is similar if not superior to uncemented THR, and provides better short term clinical outcomes. Further research, improved methodology and longer follow up are necessary to better define specific subgroups of patients in whom the relative benefits of cemented and uncemented implant fixation can be clearly demonstrated.

  10. Clinical significance of the expression of Oct-4 gene in lung cancer stem cells%肺癌干细胞基因Oct-4表达的临床意义

    Institute of Scientific and Technical Information of China (English)

    张丽丽; 林育红

    2013-01-01

    Objective To explore the expression of stem cell genes in lung cancer and the relationship between stem cell gene expression and clinical and pathological characteristics and prognosis of lung cancer.Methods Cancer stem cells were selected by flow cytometry.The differential expression of genes between lung cancer stem cells and non-lung cancer stem cells were detected by RT2 ProfilerTM PCR Array.The expression of stem cell gene Octamer-4 (Oct-4) was analyzed by immunohistochemistry staining and the relationship between Oct-4 and clinicopathological parameters of lung cancer was determined.Results Seven different genes including stem cell differentiation-related factors (CD44, Oct-4 and nestin), cell cycle regulators (APC and CDC2), and growth factors (HGF and TGF) were detected as significantly differently expressed between lung cancer stem cells and non-lung cancer stem cells.Oct-4 protein expressed significantly higher in cancerous tissues than adjacent-tumor tissues (P = 0.001).After survival analysis, the cases with highly expressed Oct-4 protein attained a significantly poorer postoperative disease-specific survival than those with none or low expressed Oct-4 protein (P = 0.001).In the Cox regression test, tumor size, lymph node metastasis and Oct-4 were detected as the independent prognostic factors (P = 0.031, 0.002 and 0.003 respectively).Conclusion Oct-4 is highly expressed in lung cancer stem cells, and may be a potential biomarker for the initiation, progression, and differentiation of lung cancer.%目的 研究肺癌干细胞的基因表达与临床特征、病理特征、预后间的关系.方法 应用流式细胞仪分选出肺癌干细胞,并应用RT2 ProfilerTM PCR仪检测肺癌干细胞与非肺癌干细胞间的差异性基因表达.应用免疫组化分析干细胞基因Octamer-4(Oct-4)的表达与临床病理特征之间的关系.应用Western-blot检测肺癌干细胞中Oct-4蛋白的表达情况.结果 肺癌干细胞与非肺癌干细胞

  11. Stem cells and stem cell therapy for diabetes mellitus:Chinese clinical trial registration information analysis%干细胞及干细胞治疗糖尿病:中国临床试验注册信息分析

    Institute of Scientific and Technical Information of China (English)

    刘宏娟

    2015-01-01

    背景:中国临床试验注册中心通过公布研究设计信息、国际统一注册号、审核研究设计、中心随机分配以保障注册临床试验的质量。目的:分析中国临床试验注册中心关于干细胞以及干细胞治疗糖尿病研究的现状。方法:检索2008至2014年中国临床试验注册中心关于干细胞研究的临床试验注册项目,从治疗疾病种类、研究类型、注册时间、注册单位、分布地区等方面对资料进行整理,并对干细胞治疗糖尿病临床试验注册项目进行深入分析。结果与结论:关于干细胞研究的项目共有82项,以治疗血液病(32/39.0%)、神经系统疾病(20/24.4%)、肝病(9/11.0%)、糖尿病(5/6.1%)的试验项目为主,注册时间集中在2012年,主要研究单位是中国武装警察部队总医院、北京大学人民医院和浙江大学医学院附属第一医院,地区分布主要在北京和浙江。关于干细胞治疗糖尿病研究的试验项目有5项,分别为中国武装警察部队总医院的脐带间充质干细胞移植治疗糖尿病研究、新桥医院的间充质干细胞移植治疗糖尿病的有效性及安全性和解放军第452医院自体骨髓干细胞移植治疗糖尿病的临床研究。中国临床试验注册中心关于干细胞以及干细胞治疗糖尿病研究的项目数量不多,提高临床试验注册数量和规范是未来发展的方向。%BACKGROUND:The Chinese Clinicaltrial Register publishes the study design information and internationaly harmonized registration number, reviews study design, and randomly assigns in order to protect the quality of registration. OBJECTIVE:To analyze the current situation of stem cels and stem cel therapy for diabetes melitus in Chinese Clinical Trial Registry. METHODS: We searched the Chinese Clinical Trial Register (2008-2014) for stem cel research, and summarized these studies from the aspects of type of disease, study type, registration

  12. Conditioning of radioactive waste solutions by cementation

    International Nuclear Information System (INIS)

    For the cementation of the low and intermediate level evaporator concentrates resulting from the reprocessing of spent fuel numerous experiments were performed to optimize the waste form composition and to characterize the final waste form. Concerning the cementation process, properties of the waste/cement suspension were investigated. These investigations include the dependence of viscosity, bleeding, setting time and hydration heat from the waste cement slurry composition. For the characterization of the waste forms, the mechanical, thermal and chemical stability were determined. For special cases detailed investigations were performed to determine the activity release from waste packages under defined mechanical and thermal stresses. The investigations of the interaction of the waste forms with aqueous solutions include the determination of the Cs/Sr release, the corrosion resistance and the release of actinides. The Cs/Sr release was determined in dependence of the cement type, additives, setting time and sample size. (orig./DG)

  13. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll;

    2013-01-01

    The cement industry is one of the major sources of CO2 emissions and is likely to contribute to further increases in the near future. The carbonate looping process has the potential to capture CO2 emissions from the cement industry, in which raw meal for cement production could be used as the...... sorbent. Cyclic experiments were carried out in a TGA apparatus using industrial cement raw meal and synthetic raw meal as sorbents, with limestone as the reference. The results show that the CO2 capture capacities of the cement raw meal and the synthetic raw meal are comparable to those of pure limestone....... The CO2 capture capacity of limestone in the raw meal is lower than for pure limestone. The difference in the CO2 capture capacity decreases with an increase in cycle number. The calcination conditions and composition are major factors that influence the CO2 capture capacity of limestone. At 850 °C in...

  14. Energetically Modified Cement (EMC) - Performance Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ronin, Vladimir; Elfgren, Lennart [Luleaa Univ. of Technology (Sweden). Centre for High Performance Cement

    2003-03-01

    Energetically Modified Cements, EMC, made of intensively milled cement (50%) and fillers (50%) of quartz or fly ash have been compared to blends of Ordinary Portland Cement, OPC, and fillers. The EMCs have better properties than other blends and are comparable to unblended OPC. This remarkable fact can probably be explained as follows. The grinding process reduces the size of both cement grains and fillers. This combined with the creation of micro defects gives the ground cement a very high degree of hydration. The increased early hydration and a better distribution of hydration products results in an extensive pore size refinement of the hardened binder. This pore size refinement leads to a favorably reduced permeability and diffusivity and very good mechanical properties.

  15. Stem cells for spine surgery.

    Science.gov (United States)

    Schroeder, Joshua; Kueper, Janina; Leon, Kaplan; Liebergall, Meir

    2015-01-26

    In the past few years, stem cells have become the focus of research by regenerative medicine professionals and tissue engineers. Embryonic stem cells, although capable of differentiating into cell lineages of all three germ layers, are limited in their utilization due to ethical issues. In contrast, the autologous harvest and subsequent transplantation of adult stem cells from bone marrow, adipose tissue or blood have been experimentally utilized in the treatment of a wide variety of diseases ranging from myocardial infarction to Alzheimer's disease. The physiologic consequences of stem cell transplantation and its impact on functional recovery have been studied in countless animal models and select clinical trials. Unfortunately, the bench to bedside translation of this research has been slow. Nonetheless, stem cell therapy has received the attention of spinal surgeons due to its potential benefits in the treatment of neural damage, muscle trauma, disk degeneration and its potential contribution to bone fusion. PMID:25621119

  16. Stem cells for spine surgery

    Institute of Scientific and Technical Information of China (English)

    Joshua Schroeder; Janina Kueper; Kaplan Leon; Meir Liebergall

    2015-01-01

    In the past few years, stem cells have become the focusof research by regenerative medicine professionals andtissue engineers. Embryonic stem cells, although capableof differentiating into cell lineages of all three germlayers, are limited in their utilization due to ethical issues.In contrast, the autologous harvest and subsequenttransplantation of adult stem cells from bone marrow,adipose tissue or blood have been experimentally utilizedin the treatment of a wide variety of diseases rangingfrom myocardial infarction to Alzheimer's disease. Thephysiologic consequences of stem cell transplantationand its impact on functional recovery have been studiedin countless animal models and select clinical trials.Unfortunately, the bench to bedside translation of thisresearch has been slow. Nonetheless, stem cell therapyhas received the attention of spinal surgeons due to itspotential benefits in the treatment of neural damage,muscle trauma, disk degeneration and its potentialcontribution to bone fusion.

  17. [Bioethical challenges of stem cell tourism].

    Science.gov (United States)

    Ventura-Juncá, Patricio; Erices, Alejandro; Santos, Manuel J

    2013-08-01

    Stem cells have drawn extraordinary attention from scientists and the general public due to their potential to generate effective therapies for incurable diseases. At the same time, the production of embryonic stem cells involves a serious ethical issue concerning the destruction of human embryos. Although adult stem cells and induced pluripotential cells do not pose this ethical objection, there are other bioethical challenges common to all types of stem cells related particularly to the clinical use of stem cells. Their clinical use should be based on clinical trials, and in special situations, medical innovation, both of which have particular ethical dimensions. The media has raised unfounded expectations in patients and the public about the real clinical benefits of stem cells. At the same time, the number of unregulated clinics is increasing around the world, making direct offers through Internet of unproven stem cell therapies that attract desperate patients that have not found solutions in standard medicine. This is what is called stem cells tourism. This article reviews this situation, its consequences and the need for international cooperation to establish effective regulations to prevent the exploitation of patients and to endanger the prestige of legitimate stem cell research. PMID:24448860

  18. Pack cementation coatings for alloys

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi-Rong; Zheng, Minhui; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States)

    1996-08-01

    The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating on a Cr-Cr{sub 2}Nb alloy in a single processing step. The morphology and composition of the coating depended both on the composition of the pack and on the composition and microstructure of the substrate. Higher Ge content in the pack suppressed the formation of CrSi{sub 2} and reduced the growth kinetics of the coating. Ge was not homogeneously distributed in the coatings. In cyclic and isothermal oxidation in air at 700 and 1050{degrees}C, the Ge-doped silicide coating protected the Cr-Nb alloys from significant oxidation by the formation of a Ge-doped silica film. The codeposition and diffusion of aluminum and chromium into low alloy steel have been achieved using elemental Al and Cr powders and a two-step pack cementation process. Sequential process treatments at 925{degrees}C and 1150{degrees}C yield dense and uniform ferrite coatings, whose compositions are close to either Fe{sub 3}Al or else FeAl plus a lower Cr content, when processed under different conditions. The higher content of Al in the coatings was predicted by thermodynamic calculations of equilibrium in the gas phase. The effect of the particle size of the metal powders on the surface composition of the coating has been studied for various combinations of Al and Cr powders.

  19. ROTARY SCREW SYSTEMS IN CEMENT

    Directory of Open Access Journals (Sweden)

    Taratuta V. D.

    2016-01-01

    Full Text Available The article presents results of research of rotary-screw systems in relation to the creation of rotary kilns for the annealing of-cuttings in the preparation of cement clinker. Using the proposed design, in comparison with known designs of similar purpose, it significantly improves performance, reduces size and power consumption through the use of rotary screw systems in the form of screw rotors and drums made hollow with sidewalls assembled from separate strips or plates of different geometrical shapes with form inside the screw breaks or smooth edges, screw surfaces and screw grooves. It is shown that the housing of the rotary kiln is expedient to produce helical surfaces whose centers of curvature are located within the housing. Using the proposed constructions rotary kiln during the firing when preparing cement wedge can increase the speed of rotation of the housing, furnaces 5-10 times due to changes in the rotary-screw systems increase efficiency and reduce the size of furnaces

  20. Cements with low Clinker Content

    Science.gov (United States)

    García-Lodeiro, I.; Fernández-Jiménez, A.; Palomo, A.

    2015-11-01

    Hybrid alkaline cements are multi-component systems containing a high percentage of mineral additions (fly ash, blast furnace slag), low proportions (alkaline activators. The substantially lower amount of clinker needed to manufacture these binders in comparison to ordinary Portland cement is both economically and ecologically beneficial. Their enormous versatility in terms of the raw materials used has made them the object of considerable interest. The present study explored the mechanical strength of binary blends mixes; B1= 20% clinker (CK) + 80% fly ash (FA) and B2=20% clinker + 80% blast furnace slag (BFS), both hydrated in the presence and absence of an alkaline activator specifically designed for this purpose. The use of the activator enhanced the development of early age strength considerably. All the hydrated matrices were characterised with XRD, SEM/EDX and (29Si and 27Al) NMR. The use of the alkaline activator generated reaction products consisting primarily of a mix of gels ((N,C)-A-S-H and C-A-S-H) whose respective proportions were found to depend upon system composition and initial reactivity.

  1. Cement and concrete options paper

    International Nuclear Information System (INIS)

    Greenhouse gas emissions associated with the production of concrete are projected to increase from 10.5 million tonnes in 1990 to almost 14 million tonnes in 2010. Over half of this amount will be non-energy related emissions of carbon dioxide resulting from the conversion of limestone to lime. According to this report by industry experts, the industry has an excellent record of improving energy efficiency and there are few easy gains remaining. Nevertheless, improvements in energy efficiency and fuel use, increased use of concrete where it can be shown to result in net reduction of GHG emissions, and partial replacement of cement by supplementary cementitious materials that involve no additional generation of GHGs, could yield an approximate reduction in carbon dioxide emissions of nearly seven million tons in 2010. The industry proposes three measures to realise these benefits: (1) encouraging replacement of fossil fuels by otherwise waste material, (2) encouraging increased use of concrete in constructing houses and roads, and (3) encouraging increased use of supplementary cementing materials. The industry is opposed to carbon or energy taxes that increase the cost of doing business, on the grounds that such taxes would adversely affect the industry's competitive position internationally. tabs

  2. Environmental health survey in asbestos cement sheets manufacturing industry.

    Science.gov (United States)

    Ansari, F A; Bihari, V; Rastogi, S K; Ashquin, M; Ahmad, I

    2007-01-01

    About 673 small-scale asbestos mining and milling facilities and 33 large - scale asbestos manufacturing plants, (17 asbestos-cement product manufacturing plants and 16 other than asbestos-cement product plants) are situated in India. The present study reveals the exposure of commercial asbestos (chrysotile) in the occupational as well as ambient air environment of the asbestos-cement (AC) sheets industry using membrane filter method of Bureau of Indian Standards (BIS). The fibre concentrations in 15 samples collected in the occupational environment at ingredient feeding site, sheet-producing site, fibre godown were 0.079, 0.057 and 0.078 f/cc, respectively and in five samples from surrounding ambient air at factory gate resulted fibre concentration of 0.071 f/cc. All the samples have shown fibre concentration lower than the threshold limit values (TLVs) prescribed by BIS. Morphological analysis of samples, further under phase contrast and polarized microscopy indicates the presence of chrysotile asbestos, which acts as carcinogen as well as co-carcinogen. A clinical examination of exposed subjects reveals that there was no case of clubbing, crepitation, ronchi and dyspnea on exertion; however, obstruction and restriction were 10.9 per cent and 25 per cent in exposed subjects, respectively while in control there were 12 per cent and 28 per cent, respectively. The study revealed that chrysotile asbestos is emitted in the occupational as well as ambient environment that may cause adverse health impact. PMID:21957367

  3. Environmental health survey in asbestos cement sheets manufacturing industry

    Directory of Open Access Journals (Sweden)

    Ansari F

    2007-01-01

    Full Text Available About 673 small-scale asbestos mining and milling facilities and 33 large - scale asbestos manufacturing plants, (17 asbestos-cement product manufacturing plants and 16 other than asbestos-cement product plants are situated in India. The present study reveals the exposure of commercial asbestos (chrysotile in the occupational as well as ambient air environment of the asbestos-cement (AC sheets industry using membrane filter method of Bureau of Indian Standards (BIS. The fibre concentrations in 15 samples collected in the occupational environment at ingredient feeding site, sheet-producing site, fibre godown were 0.079, 0.057 and 0.078 f/cc, respectively and in five samples from surrounding ambient air at factory gate resulted fibre concentration of 0.071 f/cc. All the samples have shown fibre concentration lower than the threshold limit values (TLVs prescribed by BIS. Morphological analysis of samples, further under phase contrast and polarized microscopy indicates the presence of chrysotile asbestos, which acts as carcinogen as well as co-carcinogen. A clinical examination of exposed subjects reveals that there was no case of clubbing, crepitation, ronchi and dyspnea on exertion; however, obstruction and restriction were 10.9 per cent and 25 per cent in exposed subjects, respectively while in control there were 12 per cent and 28 per cent, respectively. The study revealed that chrysotile asbestos is emitted in the occupational as well as ambient environment that may cause adverse health impact.

  4. Effect of morselized bones on binding of the canine hydroxyapatite-coated femoral stem

    Institute of Scientific and Technical Information of China (English)

    SONG Ke-guan; MA De-sheng; HOU Jian-wen; WANG Huan; YAN Jing-long; YU Zhan-ge; LIANG Zhi-zhong

    2010-01-01

    Background Non-cement femoral stems are recognized in clinical use, but there are still some problems. The aim of this research was to make non-cement femoral stems to be press-fit with the medullary cavity. Methods Twenty-four healthy adult mongrel dogs were randomly divided into experimental and control groups. In the right hip joint, an artificial femoral bone replacement surgery was conducted. For the experimental group, the replacement surgery of hydroxyapatite (HA)-coated femoral stems was done, while autogeneous morselized bone was implanted into the medullary cavity. For the control group, morselized bone was not implanted. At postoperative 1, 3, 6 months, a test for interfacial shear characteristics was conducted in the MTS810 Tester. The comparison between the two groups' bone-prostheses in shear strength for their interface from shearing destruction was made. A histological observation to check prosthesis-bone interface contact ratios and bone growth was carried out. Results For the experimental group, shear strength was 0.317 MPa in 1 month, 1.447 MPa in 3 months, and 1.621 MPa in 6 months. For the control group, shear strength was 0.195 MPa in 1 month, 1.023 MPa in 3 months, and 1.483 MPa in 6 months. The difference was statistically significant. Stereomicroscope-based observation showed that the number of trabecular bones in the experimental group was larger than that of the control group, and bone growth of the former group was better than that of the latter group. Inverted microscopic observation showed that the binding degree between the prosthesis and trabecular bone of the experimental group was higher than that of the control group. Comparatively, the experimental group's trabecular bone had more stromal cells. Conclusions The morselized bones can effectively improve the biological bonding strength and bone-contact ratios in the short term for the HA-coated femoral stem and accelerate the bonding process. The use of morselized autogenous bones

  5. Osteogenesis and angiogenesis properties of dental pulp cell on novel injectable tricalcium phosphate cement by silica doped

    International Nuclear Information System (INIS)

    β-Tricalcium phosphate (β-TCP) is an osteoconductive material in clinical. In this study, we have doped silica (Si) into β-TCP and enhanced its bioactive and osteostimulative properties. To check its effectiveness, a series of Si-doped with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of the diametral tensile strength, ions released and weight loss of cements was considered after immersion. In addition, we also examined the behavior of human dental pulp cells (hDPCs) cultured on Si-doped β-TCP cements. The results showed that setting time and injectability of the Si-doped β-TCP cements were decreased as the Si content was increased. At the end of the immersion point, weight losses of 30.1%, 36.9%, 48.1%, and 55.3% were observed for the cement doping 0%, 10%, 20%, and 30% Si into β-TCP cements, respectively. In vitro cell experiments show that the Si-rich cements promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the Si-doped in the cement is more than 20%, the amount of cells and osteogenesis protein of hDPCs was stimulated by Si released from Si-doped β-TCP cements. The degradation of β-TCP and osteogenesis of Si gives a strong reason to believe that these Si-doped β-TCP cements may prove to be promising bone repair materials. - Highlights: • The higher the Si in the cement, the shorter the setting time and the higher the DTS. • Si20-doped in TCP improved cell adhesion, proliferation and differentiation. • The Si ion stimulated collagen secreted from cells. • The Si released from substrate can promote osteogenic and angiogenic

  6. Osteogenesis and angiogenesis properties of dental pulp cell on novel injectable tricalcium phosphate cement by silica doped

    Energy Technology Data Exchange (ETDEWEB)

    Su, Ying-Fang [Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan (China); Department of Stomatology, Chung Shan Medical University Hospital, Taichung, Taiwan (China); School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Lin, Chi-Chang, E-mail: chichang31@gmail.com [Department of Anatomy, Chung Shan Medical University, Taichung City, Taiwan (China); Huang, Tsui-Hsien; Chou, Ming-Yung [Department of Stomatology, Chung Shan Medical University Hospital, Taichung, Taiwan (China); School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Yang, Jaw-Ji, E-mail: jjyang@csmu.edu.tw [Department of Chemical and Materials Engineering, Tunghai University, Taichung, Taiwan (China); Shie, Ming-You, E-mail: eviltacasi@gmail.com [Department of Anatomy, Chung Shan Medical University, Taichung City, Taiwan (China)

    2014-09-01

    β-Tricalcium phosphate (β-TCP) is an osteoconductive material in clinical. In this study, we have doped silica (Si) into β-TCP and enhanced its bioactive and osteostimulative properties. To check its effectiveness, a series of Si-doped with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of the diametral tensile strength, ions released and weight loss of cements was considered after immersion. In addition, we also examined the behavior of human dental pulp cells (hDPCs) cultured on Si-doped β-TCP cements. The results showed that setting time and injectability of the Si-doped β-TCP cements were decreased as the Si content was increased. At the end of the immersion point, weight losses of 30.1%, 36.9%, 48.1%, and 55.3% were observed for the cement doping 0%, 10%, 20%, and 30% Si into β-TCP cements, respectively. In vitro cell experiments show that the Si-rich cements promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the Si-doped in the cement is more than 20%, the amount of cells and osteogenesis protein of hDPCs was stimulated by Si released from Si-doped β-TCP cements. The degradation of β-TCP and osteogenesis of Si gives a strong reason to believe that these Si-doped β-TCP cements may prove to be promising bone repair materials. - Highlights: • The higher the Si in the cement, the shorter the setting time and the higher the DTS. • Si20-doped in TCP improved cell adhesion, proliferation and differentiation. • The Si ion stimulated collagen secreted from cells. • The Si released from substrate can promote osteogenic and angiogenic.

  7. Clinical applications of bone marrow stem cells to treat liver diseases: recent progress%骨髓干细胞治疗肝脏疾病的临床应用进展

    Institute of Scientific and Technical Information of China (English)

    孟云超; 姜海行; 张君红

    2011-01-01

    In recent years, great advances have been made in the treatment of liver diseases, such as fulminant and chronic hepatic failure, end-stage liver disease and inherited metabolic disorders, by bone marrow stem cell transplantation. Stem cell transplantation possesses advantages of low cost, easy obtainment of stem cells, and little or no immune rejection and therefore has good efficacy, safety and tolerability. Although liver transplantation is an effective way for the treatment of end-stage liver disease, it has limited clinical applications due to the shortage of organ donors, complicated operation procedure, severe complications, immunological rejection and high cost. Therefore, bone marrow stem cell transplantation has shed light on the treatment of end-stage liver diseases. In this article we review the clinical applications of bone marrow stem cell transplantation in the treatment of liver diseases.%近年来随着研究的不断深入,骨髓干细胞移植在治疗急慢性肝功能衰竭、终末期肝病及遗传代谢性肝病等方面有了很大的进展,其在近期疗效、安全性、耐受性等方面获得了肯定,且因其本身的优势(如费用低廉、取材方便、不存在免疫排斥反应等)而越来越受到重视.虽然肝移植是治疗各种终末期肝病的有效方法,但由于供肝来源不足、操作复杂、并发症多、移植后免疫排斥及治疗费用昂贵等原因,限制了临床肝移植的发展.因此,自开展干细胞研究以来,骨髓干细胞移植为肝病患者带来了福音.本文就近年来骨髓干细胞移植治疗肝脏疾病的相关临床研究作一综述.

  8. Advance in hematopoietic stem cells transplantation for leukemia

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiao-jun

    2008-01-01

    @@ During the past 50 years, intensive studies into the characteristics of hematopoietic stem cell transplantation immunology and the emergence of new immunosuppressant and anti-infective drugs have significantly improved the clinical result of hematopoietic stem cell transplantation (HSCT).

  9. New perspectives in human stem cell therapeutic research

    OpenAIRE

    Trounson Alan

    2009-01-01

    Abstract Human stem cells are in evaluation in clinical stem cell trials, primarily as autologous bone marrow studies, autologous and allogenic mesenchymal stem cell trials, and some allogenic neural stem cell transplantation projects. Safety and efficacy are being addressed for a number of disease state applications. There is considerable data supporting safety of bone marrow and mesenchymal stem cell transplants but the efficacy data are variable and of mixed benefit. Mechanisms of action o...

  10. Thyroid stem cells: lessons from normal development and thyroid cancer

    OpenAIRE

    Thomas, Dolly; Friedman, Susan; Lin, Reigh-Yi

    2008-01-01

    Ongoing advances in stem cell research have opened new avenues for therapy for many human disorders. Until recently, however, thyroid stem cells have been relatively understudied. Here, we review what is known about thyroid stem cells and explore their utility as models of normal and malignant biological development. We also discuss the cellular origin of thyroid cancer stem cells and explore the clinical implications of cancer stem cells in the thyroid gland. Since thyroid cancer is the most...

  11. Potential Use of Stem Cells for Kidney Regeneration

    OpenAIRE

    Takashi Yokoo; Kei Matsumoto; Shinya Yokote

    2011-01-01

    Significant advances have been made in stem cell research over the past decade. A number of nonhematopoietic sources of stem cells (or progenitor cells) have been identified, including endothelial stem cells and neural stem cells. These discoveries have been a major step toward the use of stem cells for potential clinical applications of organ regeneration. Accordingly, kidney regeneration is currently gaining considerable attention to replace kidney dialysis as the ultimate therapeutic strat...

  12. Fracture resistance of monolithic zirconia crowns: The importance of the compressive strength of the dental cements used.

    OpenAIRE

    Lægreid, Solveig Jenssen; Nergård, John Magnus

    2014-01-01

    Background: Monolithic zirconia crowns have not been used for a very long period in dentistry even though zirconia with veneering porcelain, as crown and bridge material has been used for several years with great clinical success. Several different luting materials have been purposed for zirconia but concerning monolithic zirconia the knowledge of the influence of the cement seem to be limited. The aim of the study was to investigate three different cements (one phosphate, one self adhesive a...

  13. Development of a novel aluminum-free glass ionomer cement based on magnesium/strontium-silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Ae [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Abo-Mosallam, Hany A. [Glass Research Department, National Research Centre, Dokki, Cairo (Egypt); Lee, Hye-Young [Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Kim, Gyu-Ri [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Kim, Hae-Won [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Lee, Hae-Hyoung, E-mail: haelee@dku.edu [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of)

    2014-09-01

    The effects of strontium substitution for magnesium in a novel aluminum-free multicomponent glass composition for glass ionomer cements (GICs) were investigated. A series of glass compositions were prepared based on SiO{sub 2}-P{sub 2}O{sub 5}-CaO-ZnO-MgO{sub (1-X)}-SrO{sub X}-CaF{sub 2} (X = 0, 0.25, 0.5 and 0.75). The mechanical properties of GICs prepared were characterized by compressive strength, flexural strength, flexural modules, and microhardness. Cell proliferation was evaluated indirectly by CCK-8 assay using various dilutions of the cement and rat mesenchyme stem cells. Incorporation of strontium instead of magnesium in the glasses has a significant influence on setting time of the cements and the properties. All mechanical properties of the GICs with SrO substitution at X = 0.25 were significantly increased, then gradually decreased with further increase of the amount of strontium substitution in the glass. The GIC at X = 0.25, also, showed an improved cell viability at low doses of the cement extracts in comparison with other groups or control without extracts. The results of this study demonstrate that the glass compositions with strontium substitution at low levels can be successfully used to prepare aluminum-free glass ionomer cements for repair and regeneration of hard tissues. - Highlights: • We developed multicomponent glass compositions for a novel aluminum-free glass ionomer cement (GIC). • The effects of MgO replacement with SrO in the glasses on the mechanical properties and cell proliferation were evaluated. • Substitution of MgO with SrO at low levels led to improvement of mechanical properties and cell viability of the cements. • Microstructural degradations in the cement matrix of the GICs with strontium at high levels were observed after aging.

  14. Development of a novel aluminum-free glass ionomer cement based on magnesium/strontium-silicate glasses

    International Nuclear Information System (INIS)

    The effects of strontium substitution for magnesium in a novel aluminum-free multicomponent glass composition for glass ionomer cements (GICs) were investigated. A series of glass compositions were prepared based on SiO2-P2O5-CaO-ZnO-MgO(1-X)-SrOX-CaF2 (X = 0, 0.25, 0.5 and 0.75). The mechanical properties of GICs prepared were characterized by compressive strength, flexural strength, flexural modules, and microhardness. Cell proliferation was evaluated indirectly by CCK-8 assay using various dilutions of the cement and rat mesenchyme stem cells. Incorporation of strontium instead of magnesium in the glasses has a significant influence on setting time of the cements and the properties. All mechanical properties of the GICs with SrO substitution at X = 0.25 were significantly increased, then gradually decreased with further increase of the amount of strontium substitution in the glass. The GIC at X = 0.25, also, showed an improved cell viability at low doses of the cement extracts in comparison with other groups or control without extracts. The results of this study demonstrate that the glass compositions with strontium substitution at low levels can be successfully used to prepare aluminum-free glass ionomer cements for repair and regeneration of hard tissues. - Highlights: • We developed multicomponent glass compositions for a novel aluminum-free glass ionomer cement (GIC). • The effects of MgO replacement with SrO in the glasses on the mechanical properties and cell proliferation were evaluated. • Substitution of MgO with SrO at low levels led to improvement of mechanical properties and cell viability of the cements. • Microstructural degradations in the cement matrix of the GICs with strontium at high levels were observed after aging

  15. Stem Cells in Regenerative Endodontics

    OpenAIRE

    Maryam Forghani

    2014-01-01

    Background Currently, clinical endodontics includes procedures that are based on the ability of stem cells to accomplish repair (eg, direct pulp capping, apexogenesis, apexification, and even pulpal regeneration). An attempt is made to critically assess the current status in pulp regeneration therapy. Methods: Systematically, 2 distinctly different strategies exist involving stem cells for the repair and/or regeneration of damaged tissues: first, the acellular approach with in situ s...

  16. 骨水泥强化椎弓根螺钉固定治疗伴骨质疏松腰椎管狭窄症临床应用%Clinical application of bone cement augmentation of pedicle screws in lumbar spinal canal stenosis with osteoporosis

    Institute of Scientific and Technical Information of China (English)

    孙治国; 王浩; 赵喜滨; 袁宏

    2015-01-01

    Objective To investigate the clinical application of bone cement augmentation of pedicle screws in lumbar spinal canal stenosis with osteoporosis.Methods From June 2010 to June 2013,13 patients ( 4 males,9 females ) of lumbar spinal canal stenosis with osteoporosis were recruited,with an average age of 68 years old ( range: 61-77 years ).Nine cases were in stage two.Four cases were in stage three.Assessing osteoporosis according to Jikei,there were 4 cases of stage Ⅱ and 9 cases of Ⅲ.Bone cement augmentation of the screw channel was conducted before pedicle screw ifxation.Thirty-six bone cement augmented pedicle screws were implanted.Using X-ray during and after the operation to compare pedicle screw positions and observe the stability.Visual analogue scores ( VAS ) was applied to evaluate low back pain and leg pain 1 day before surgery,7 days and 3 months postoperatively.Results Complications due to the bone cement leakage,heat-induced effects and toxicity in the screw implantation process did not occur.The low back pain and leg pain symptoms were improved signiifcantly 1 week postoperatively.VAS were ( 2.20 ± 1.18 ) points and ( 2.32 ± 0.35 ) points respectively,with statistical signiifcance comparing with preoperative condition (P<0.05 ).VAS were ( 1.82 ± 0.15 ) points and ( 1.14 ± 0.44 ) points in 3 months postoperatively,with no statistical significance comparing with the condition 1 week postoperatively (P>0.05 ).Thirteen patients were followed up.The average followed up time was 14 months ( range: 8-16 months ).Thirteen cases obtained bony fusion.X-ray showed no loosening,fracture or falling of the internal fixation.No radiolucent lines appeared around the screws.Conclusions Application of bone cement augmentation of pedicle screws in lumbar spinal canal stenosis with osteoporosis can receive satisfactory short-term clinical outcomes.%目的 探讨骨水泥强化椎弓根螺钉在腰椎管狭窄伴骨质疏松患者的临床疗效.方法 2010年6

  17. Cancer Stem Cells

    OpenAIRE

    Aurelio Lorico; Eric Deutsch; Bo Lu; Shih-Hwa Chiou

    2011-01-01

    Cancer Stem Cells (CSCs) are a small subpopulation of cells within tumors with capabilities of self-renewal, differentiation, and tumorigenicity when transplanted into an animal host. A number of cell surface markers such as CD44, CD24, and CD133 are often used to identify and enrich CSCs. A regulatory network consisting of microRNAs and Wnt/β-catenin, Notch, and Hedgehog signaling pathways controls the CSC properties. The clinical relevance of CSCs has been strengthened by emerging evidence,...

  18. Registered clinical studies of stem cells for non-tumorous diseases%干细胞在非肿瘤性疾病中的注册临床研究

    Institute of Scientific and Technical Information of China (English)

    陈建华; 张军; 胡祥

    2012-01-01

    -by-year. But there are no authentic data for their indictions. Researchers are still working to identify potential indications for stem cells in non-tumorous conditions. Objective To provide consultative information on selecting potential indications of stem cells for non-tumorous conditions, we screen the clinical trials on website: http://www.clinicaltrials.gov. Methods On May 10th, 2012, a search of the electronic database provided by the National Institute of Health website (http://www. clinicaltrials.gov) was conducted by using corresponding search formulas to define registered clinical research studies/trials in association with stem cells as an intervention in human trials for non-tumorous conditions. There was no restriction for language, research location, and research race. Results and Conclusion Of 2801 studies identified in the initial search, firstly, 220 terminated or suspended or withdrawn studies were excluded and further 8 repeated studies were excluded. Secondly, 1582 tumorous conditions-related studies were excluded. Lastly, 385 studies were excluded for lack of accordance with the main purpose. A total of 606 research studies were entered into the analysis and reviewed. Among them, about 26% (157) trials were cardiocerebrovascular diseases most of them are ischemic cardiocerebrovascular diseases;(101/606) were autoimmune disorders or graft versus host diseases after organ transplantation;the remaining third were genetic disorders (83/606) and diabetes (37/606) and liver diseases (33/606) and lower limb ischemic diseases (35/606). From 1999 to 2012, the number of registered studies increased quickly, which reaches 141 trials in 2011. These reflected stem cell for treating diseases has become a new therapy apart from traditional treatment. The main mechanism of stem cells are self-renewal and multiplex differentiation potential, and promote tissue repair/regeneration. The immune adjustment mechanism of mesenchymal stem cells in immune disease is still one of

  19. Extraoral Cementation Technique to Minimize Cement-Associated Peri-implant Marginal Bone Loss: Can a Thin Layer of Zinc Oxide Cement Provide Sufficient Retention?

    Science.gov (United States)

    Frisch, Eberhard; Ratka-Krüger, Petra; Weigl, Paul; Woelber, Johan

    2016-01-01

    This report describes the use of laboratory-fabricated crown intaglio replicas for extraorally prepared cementation of fixed restorations to implants. This technique minimizes excess cement and may therefore reduce the risk of cement-related marginal peri-implant bone loss. It is unclear whether the remaining thin layer of luting agent provides sufficient retention if low-adhesive zinc oxide (ZnO) cement is used. In 85 consecutive patients, 113 single crowns were cemented to implants using extraoral cementation technique (ECT) and ZnO cement. All patients were followed for 6 months and investigated for decementation. Seven events of decementation (incidence: 6.19%) were found in 7 patients (8.24%). ECT may represent a viable cementation technique for implant-supported single crowns, even using low-adhesion cements. PMID:27479343

  20. A randomized study on migration of the Spectron EF and the Charnley flanged 40 cemented femoral components using radiostereometric analysis at 2 years

    OpenAIRE

    Kadar, Thomas; Hallan, Geir; Aamodt, Arild; Indrekvam, Kari; Badawy, Mona; Havelin, Leif Ivar; Stokke, Terje; Haugan, Kristin; Espehaug, Birgitte; Furnes, Ove

    2011-01-01

    Background and purpose: We performed a randomized study to determine the migration patterns of the Spectron EF femoral stem and to compare them with those of the Charnley stem, which is regarded by many as the gold standard for comparison of implants due to its extensive documentation.Patients and methods: 150 patients with a mean age of 70 years were randomized, single-blinded, to receive either a cemented Charnley flanged 40 monoblock, stainless steel, vaquasheen surface ...

  1. Modelling Quartz Cementation of Quartzose Sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Wangen, Magnus

    1999-10-01

    Porosity estimation in sandstones is an important part of oil reservoir quality estimations, as porosity is lost during burial because of mechanical compaction and quartz cementation. In this report, cementation of quartzose sandstones is modelled assuming that the main source of silica is quartz dissolved at stylolites. The cementation process is shown to operate in one of two different regimes depending on the Damkohler number for diffusion. The regime, where diffusion of silica from the stylolites is a faster process than precipitation, is characterized by a nearly constant supersaturation between the stylolites. This regime, which spans the depth interval of quartz cementation for close stylolites, allows approximate analytical expressions for the porosity evolution as a function of time and temperature. An expression is derived for the temperature where half the initial porosity is lost during constant burial along constant thermal gradient. This expression is used to study the sensitivity of all parameters which enter the cementation process. The cementation process is shown to be particularly sensitive to the activation energy for quartz dissolution. The expression for the porosity decrease under constant burial is generalized to any piecewise linear burial and temperature history. The influence of the burial histories on the cementation process is studied. 32 refs., 16 figs., 1 tab.

  2. Three big Cs: climate, cement and China

    Energy Technology Data Exchange (ETDEWEB)

    Nordqvist, Joakim [Lund Univ., Lund (Sweden); Boyd, Christopher [Lafarge (France); Klee, Howard [World Business Council for Sustainable Development (Switzerland)

    2003-09-30

    Cement is a low-cost construction material whose manufacture generates significant carbon dioxide emissions. As these emissions enter a carbon-constrained world, they may ultimately have a significant impact on the industry's financial performance. Consequently, the cement industry is developing a response to climate change management and the connected political process. Ten of the world's leading cement-producing corporations, representing more than one-third of global cement production, published a joint Agenda for Action in 2002 to address sustainability issues for the industry, including climate change. Other issues identified are emissions reduction, use of fuels and raw materials, employee health and safety, local impacts on land and communities, and internal business processes. Examining the rationale for, and the effects of, proactive climate initiatives in the cement sector, this paper elaborates on the conditions for the spread of cement-related climate action to China, where more than one-third of global cement production occurs, 80% of which involves inefficient kilns using outdated, highly polluting technology. (Author)

  3. Effect of cements on fracture resistance of monolithic zirconia crowns

    OpenAIRE

    Nakamura, Keisuke; Mouhat, Mathieu; Nergård, John Magnus; Lægreid, Solveig Jenssen; Kanno, Taro; Milleding, Percy; Örtengren, Ulf

    2016-01-01

    Abstract Objectives The present study investigated the effect of cements on fracture resistance of monolithic zirconia crowns in relation to their compressive strength. Materials and methods Four different cements were tested: zinc phosphate cement (ZPC), glass-ionomer cement (GIC), self-adhesive resin-based cement (SRC) and resin-based cement (RC). RC was used in both dual cure mode (RC-D) and chemical cure mode (RC-C). First, the compressive strength of each cement was tested according to a...

  4. Laboratory studies on the longevity of cement grouts

    International Nuclear Information System (INIS)

    This paper describes laboratory studies of the longevity of cement-based grouts being carried out as part of the International Stripa Project Phase III. The longevity properties determined for a reference grout (90% Sulphate Resistant Portland Cement, 10% silica fume, 0.4< water/cement<0.6 and superplasticizer) are compared with those of a slag cement grout. Laboratory tests have been carried out to determine the following: the mechanistic function of superplasticizer in fresh cement pastes; the leachability of the sorbed superplasticizer and its location in the structure of hardened cement paste; and the general leaching properties of selected cement-based grouts

  5. Geochemical modelling of long-term cement degradation

    International Nuclear Information System (INIS)

    The objective of this study was to investigate geochemical reactions related to long-term cement degradation caused by interaction with groundwater using a geochemical model. The results from modelling showed changes in chemical composition of pore water and cement compounds resulted from cement hydration and degradation. In this study, the volume of each cement compound was also calculated using a geochemical model. The porosity of cement caused by degradation was estimated using the change in volume of each cement compound. The results from this study provide important information to evaluate long-term durability of cement in groundwater system, which is closely related to the safety of radioactive waste disposal repository

  6. Alkylator-Induced and Patient-Derived Xenograft Mouse Models of Therapy-Related Myeloid Neoplasms Model Clinical Disease and Suggest the Presence of Multiple Cell Subpopulations with Leukemia Stem Cell Activity

    Science.gov (United States)

    Johnson, Carl; Gratzinger, Dita; Majeti, Ravindra

    2016-01-01

    Acute myeloid leukemia (AML) is a heterogeneous group of aggressive bone marrow cancers arising from transformed hematopoietic stem and progenitor cells (HSPC). Therapy-related AML and MDS (t-AML/MDS) comprise a subset of AML cases occurring after exposure to alkylating chemotherapy and/or radiation and are associated with a very poor prognosis. Less is known about the pathogenesis and disease-initiating/leukemia stem cell (LSC) subpopulations of t-AML/MDS compared to their de novo counterparts. Here, we report the development of mouse models of t-AML/MDS. First, we modeled alkylator-induced t-AML/MDS by exposing wild type adult mice to N-ethyl-N-nitrosurea (ENU), resulting in several models of AML and MDS that have clinical and pathologic characteristics consistent with human t-AML/MDS including cytopenia, myelodysplasia, and shortened overall survival. These models were limited by their inability to transplant clinically aggressive disease. Second, we established three patient-derived xenograft models of human t-AML. These models led to rapidly fatal disease in recipient immunodeficient xenografted mice. LSC activity was identified in multiple HSPC subpopulations suggesting there is no canonical LSC immunophenotype in human t-AML. Overall, we report several new t-AML/MDS mouse models that could potentially be used to further define disease pathogenesis and test novel therapeutics. PMID:27428079

  7. 干细胞治疗缺血性心脏病的临床研究进展%Clinical Trials Using Stem Cell Therapy for Ischemic Heart Diseases

    Institute of Scientific and Technical Information of China (English)

    何华

    2012-01-01

    缺血性心脏病及其所致的心力衰竭是全球范围内的主要死因,急性心肌梗死导致不可逆的大范围心肌细胞损失和随后的心室重塑是慢性心功能不全和劳动力永久丧失的主要原因.干细胞治疗缺血性心脏病的实验研究已显示出巨大的潜力,而近年进行的相关临床研究也已取得重要进展.现对干细胞治疗缺血性心脏病的相关临床研究进展作一综述.%Globally, ischemic heart diseases (IHD) and heart failure resulting from IHD are major causes of death. Additionally, the loss of myocardial cells due to acute myocardial infarction and subsequent ventricle remodeling is a cause of chronic heart failure. Experimental studies and related clinical trials using stem cell therapy for IHD have shown potential. This article reviews clinical studies using stem cell therapy for IHD.

  8. Adhesive Cementation of Indirect Composite Inlays and Onlays: A Literature Review.

    Science.gov (United States)

    D'Arcangelo, Camillo; Vanini, Lorenzo; Casinelli, Matteo; Frascaria, Massimo; De Angelis, Francesco; Vadini, Mirco; D'Amario, Maurizio

    2015-09-01

    The authors conducted a literature review focused on materials and techniques used in adhesive cementation for indirect composite resin restorations. It was based on English language sources and involved a search of online databases in Medline, EMBASE, Cochrane Library, Web of Science, Google Scholar, and Scopus using related topic keywords in different combinations; it was supplemented by a traditional search of peer-reviewed journals and cross-referenced with the articles accessed. The purpose of most research on adhesive systems has been to learn more about increased bond strength and simplified application methods. Adherent surface treatments before cementation are necessary to obtain high survival and success rates of indirect composite resin. Each step of the clinical and laboratory procedures can have an impact on longevity and the esthetic results of indirect restorations. Cementation seems to be the most critical step, and its long-term success relies on adherence to the clinical protocols. The authors concluded that in terms of survival rate and esthetic long-term outcomes, indirect composite resin techniques have proven to be clinically acceptable. However, the correct management of adhesive cementation protocols requires knowledge of adhesive principles and adherence to the clinical protocol in order to obtain durable bonding between tooth structure and restorative materials. PMID:26355440

  9. Fracture model for cemented aggregates

    Directory of Open Access Journals (Sweden)

    Aleksander Zubelewicz

    2013-01-01

    Full Text Available A mechanisms-based fracture model applicable to a broad class of cemented aggregates and, among them, plastic-bonded explosive (PBX composites, is presented. The model is calibrated for PBX 9502 using the available experimental data under uniaxial compression and tension gathered at various strain rates and temperatures. We show that the model correctly captures inelastic stress-strain responses prior to the load peak and it predicts the post-critical macro-fracture processes, which result from the growth and coalescence of micro-cracks. In our approach, the fracture zone is embedded into elastic matrix and effectively weakens the material's strength along the plane of the dominant fracture.

  10. Thermal behavior of asphalt cements

    International Nuclear Information System (INIS)

    Asphalt cements are highly complex mixtures of hydrocarbon molecules whose thermal behavior is of prime importance for petroleum and road industry. From DSC, the determination of several thermal properties of asphalts is given, e.g. glass-transition temperature and crystallized fraction content.The dissolution of a pure n-paraffin CnH2n+2 in an asphalt, as seen by DSC, should be a single peak. For 20g of these glasses change with time and temperature. The formation of the crystallized phases is superposed to the enthalpic relaxation of the glasses, making a kinetic study very difficult. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  11. Silica Transport and Cementation in Quartz Aggregates

    Science.gov (United States)

    Pebble, C.; Farver, J.; Onasch, C.; Winslow, D.

    2008-12-01

    Silica transport and cementation in quartz aggregates have been experimentally investigated. Starting materials include a natural quartz arenite (Pocono sandstone), sized clasts of synthetic quartz, and sized grains of disaggregated natural sandstones. Experimental charges consisted of amorphous silica powder (~25 mg), AlCl3 powder (~3 mg), 25 wt% NaCl brine solution (~20 mg), and the starting material (~150 mg). The charges were weld-sealed in gold capsules and run in cold-seal pressure vessels at 300°C to 600°C at 150 MPa confining pressure for up to 4 weeks. Detailed calibrations of the furnaces indicate the maximum temperature variation across the length of the sample charges (3-7mm) was vacuum impregnated with epoxy containing a blue dye and sawn in half along the long axis of the sample charge. The nature and amount of silica transport and cementation in the samples was determined by a combination of Cathodoluminescence (CL), Light Microscopy (LM), and Scanning Electron Microscopy (SEM). Photomosaics of the samples were collected and the amount of cement, porosity, and average grain sizes were determined by point-counting. The cement was easily recognized from the quartz grains by the difference in luminescence. The experiments indicate that the presence of amorphous silica results in rapid silica cementation in quartz aggregates (e.g., up to 12% cement by volume in 4 weeks at 450°C). The amount of cementation is a function of substrate type, time, temperature, and ionic strength of the brine. The rate of silica transport through the length of the experimental charge appears to be limited by the silica solubility and its rapid depletion by cementation. Although most of the cement was derived from the amorphous silica, evidence for local dissolution-precipitation was observed. The experiments demonstrate that the mobility of silica, and consequent precipitation of cement, does not require a temperature or pressure gradient as is commonly assumed. Rather

  12. INFLUENCE OF GLASS CULLET IN CEMENT PASTES

    Institute of Scientific and Technical Information of China (English)

    A.Karamberi; E.Chaniotakis; D.Papageorgiou; A.Moutsatsou

    2006-01-01

    The present study investigates glass and cement compatibility with a view to use glass as a cement replacement. Amber, flint and green glasses were chosen due to their prevalence in the Greek market as packaging materials. The factors under investigation were the pozzolanicity of the glass cullet, the hydration rate and the mechanical strength development of the cement pastes, as well as the expansion of the specimens due to alkali-silica reaction.Moreover, the potential enhancement of glass pozzolanic activity was examined. The results of the study were encouraging to show the potentiality of utilising glass cullet in cementitious products.

  13. Shrinkage Properties of Cement Stabilized Gravel

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard

    2014-01-01

    shrinkage properties of cement stabilized gravel have been documented under various temperature and relative humidity conditions. Two cement contents corresponding to a 28-days compressive strength of 6.2 MPa and 12.3 MPa have been tested and compared. It is found that the coefficient of linear expansion...... for the two cement contents is 9.9 × 10-6 ⁰C-1 and 11.3 × 10-6 ⁰C-1, respectively. Furthermore, it is found that reflecting cracking can mainly be explained by temperature dependent shrinkage rather than moisture dependent shrinkage....

  14. Operating experience with KRAFTWERK UNION cementation line

    International Nuclear Information System (INIS)

    A facility is described designed for fixation in a cement matrix of the radioactive concentrate produced by thickening waste water from the Bohunice nuclear power plant. The cementation line output is 0.6 m3 concentrate/h. The concentrate is put in 200 l drums. The individual operating units, cement management, air conditioning, dosimetric monitoring and the building part are described. The requirements for the operators and the assessment of the quality of raw materials and the product are discussed. (M.D.). 3 figs., 4 refs

  15. Reinforcement of osteosynthesis screws with brushite cement.

    Science.gov (United States)

    Van Landuyt, P; Peter, B; Beluze, L; Lemaître, J

    1999-08-01

    The fixation of osteosynthesis screws remains a severe problem for fracture repair among osteoporotic patients. Polymethyl-methacrylate (PMMA) is routinely used to improve screw fixation, but this material has well-known drawbacks such as monomer toxicity, exothermic polymerization, and nonresorbability. Calcium phosphate cements have been developed for several years. Among these new bone substitution materials, brushite cements have the advantage of being injectable and resorbable. The aim of this study is to assess the reinforcement of osteosynthesis screws with brushite cement. Polyurethane foams, whose density is close to that of cancellous bone, were used as bone model. A hole was tapped in a foam sample, then brushite cement was injected. Trabecular osteosynthesis screws were inserted. After 24 h of aging in water, the stripping force was measured by a pull-out test. Screws (4.0 and 6.5 mm diameter) and two foam densities (0.14 and 0.28 g/cm3) were compared. Cements with varying solid/liquid ratios and xanthan contents were used in order to obtain the best screw reinforcement. During the pull-out test, the stripping force first increases to a maximum, then drops to a steady-state value until complete screw extraction. Both maximum force and plateau value increase drastically in the presence of cement. The highest stripping force is observed for 6.5-mm screws reinforced with cement in low-density foams. In this case, the stripping force is multiplied by 3.3 in the presence of cement. In a second experiment, cements with solid/liquid ratio ranging from 2.0 to 3.5 g/mL were used with 6.5-mm diameter screws. In some compositions, xanthan was added to improve injectability. The best results were obtained with 2.5 g/mL cement containing xanthan and with 3.0 g/mL cements without xanthan. A 0.9-kN maximal stripping force was observed with nonreinforced screws, while 1.9 kN was reached with reinforced screws. These first results are very promising regarding screw

  16. Clinical studies on the ex-vivo expansion of autologous adipose derived stem cells for the functional reconstruction of mucous membrane in empty nose syndrome

    Directory of Open Access Journals (Sweden)

    Liang LI

    2014-10-01

    Full Text Available Objective To analyze and evaluate the feasibility and effectiveness of using autologous adipose derived stem cells (ASCs for rebuilding the function of nasal mucosa in patients with empty nose syndrome (ENS. Methods Autologous adipose tissue 15-20ml were obtained from each of 5 ENS patients admitted from Aug. 2013 to Feb. 2014, and from which stem cells were isolated, cultured and expanded in vitro. The phenotype, differentiation, and genetic stability of the third generation of amplified stem cells were identified. For the patients with rudimental turbinate (n=3, ASCs were injected into the damaged nasal mucosa for 4 times (once every 10 days. For the patients with no rudimental turbinate (n=2, autologous pure fat granules 1-5ml were extracted after 3 times of ASCs injection into the damaged nasal mucosa, and mixed with the 3rd-6th generation of ASCs for inferior or middle nasal turbinate angioplasty. Nasal endoscopic examination was performed before treatment and 3, 6 and 9 months after treatment for comparison, and the data of SNOT-20 questionnaire, nasality resistance and nasal mucociliary clearance action were statistically analyzed. Results With injection transplantation of the 3rd-6th generation of ASCs in 2 patients with no rudimental turbinate, and 3, 6 and 9 months after the combined ASCs and fat granules transplantation in 3 patients with rudimental turbinate, nasal endoscopy showed that no obvious absorption in conchoplasty, nasal mucosa was improved significantly, and same as SNOT-20 scores, with statistically significant difference (P0.05. Conclusions The reconstruction of mucosa function by nasal turbinate angioplasty combined with adipose derived stem cells and autologous adipose transplantation may significantly improve the symptoms in patients with ENS with lasting effects. It is a new procedure which is helpful for the mucosal repair in patients with ENS. DOI: 10.11855/j.issn.0577-7402.2014.10.11

  17. Effect of cementing technique and cement type on thermal necrosis in hip resurfacing arthroplasty - a numerical study

    NARCIS (Netherlands)

    Janssen, D.; Srinivasan, P.; Scheerlinck, T.; Verdonschot, N.J.J.

    2012-01-01

    Femoral fractures within resurfacing implants have been associated with bone necrosis, possibly resulting from heat generated by cement polymerization. The amount of heat generated depends on cement mantle volume and type of cement. Using finite element analysis, the effect of cement type and volume

  18. Foamed cement for squeeze cementing low-pressure, highly permeable reservoirs

    International Nuclear Information System (INIS)

    Four different cement squeezing techniques have been used on wells producing from the Keg River formation in the Rainbow Lake area of Alberta, Canada. This paper evaluates 151 cement squeeze treatments performed at 96 wellsites and compares the use of foam cement vs. conventional squeeze treatments and techniques. Discussion includes key aspects, such as candidate selection, slurry design, treatment design, economic evaluation, and operational considerations

  19. Voids/Cement Ratio Controlling Tensile Strength of Cement-Treated Soils

    OpenAIRE

    Nilo Cesar Consoli; Antonio Viana da Fonseca; Rodrigo Caberlon Cruz; Sara Rios Silva

    2011-01-01

    The improvement of locally available soils with cement can provide great advantages, including avoiding the need to borrow volumes of appropriate material and disposing of the local soil in deposits. This research aims to quantify the influence of the amount of cement, the porosity, and the voids/cement ratio in the assessment of splitting tensile strength (q(t)), also known as indirect diametrical tensile (IDT) strength, of three distinct soils from Brazil and Portugal. From Brazil, clayey s...

  20. Effect of Abutment Modification and Cement Type on Retention of Cement-Retained Implant Supported Crowns

    OpenAIRE

    Mitra Farzin; Kianoosh Torabi; Ahmad Hasan Ahangari; Reza Derafshi

    2014-01-01

    Objective: Provisional cements are commonly used to facilitate retrievability of cement-retained fixed implant restorations; but compromised abutment preparation may affect the retention of implant-retained crowns.The purpose of this study was to investigate the effect of abutment design and type of luting agent on the retentive strength of cement-retained implant restorations. Materials and Method: Two prefabricated abutments were attached to their corresponding analogs and embedded in an ac...

  1. ANALYSIS OF UNCERTAINTIES IN CEMENT INDUSTRY IN TURKEY

    OpenAIRE

    Kemal Yildirim; Omer Arioz

    2013-01-01

    Cement industry having 4,5 billion Dollars revenue and 1 billion Dollar export volume plays very important role in Turkey’s economy. Turkish cement industry is very sensitive to economic crisis and involves many uncertainties. In this study, price uncertainties, technological uncertainties, and price-technological uncertainties in Turkish cement industry were analyzed. The cement demand is mostly affected by demand to ready mixed concrete. Demand to cement is also related to the picture of co...

  2. Composite cements containing natural pozzolan and granulated blast furnace slag

    OpenAIRE

    Irassar, E. F.; Rahhal, V.F.; Donza, H. A.; Menéndez, G.; Bonavetti, V. L.

    2006-01-01

    For reasons of market demand and Portland cement production,the manufacture of cements with two or more separately ground additions to produce customized cements is becoming common practice.When pozzolan or slag content in this type of cements is high, however, the initial strength of the resulting product may be adversely impacted. This problem can be minimized by activating one or both of the replacement materials. The present study analyzes the effect of Portland cement additions such as p...

  3. Traditional pedicle screws versus cement-augmented pedicle screws in osteoporotic spine surgery:a comparative clinical study%普通椎弓根螺钉与骨水泥型椎弓根螺钉在骨质疏松脊柱手术中的比较研究

    Institute of Scientific and Technical Information of China (English)

    樊勇; 杨红军; 雷伟; 吴子祥; 严亚波; 张扬; 桑宏勋

    2015-01-01

    目的:分析总结普通椎弓根螺钉与骨水泥型椎弓根螺钉在骨质疏松患者脊柱手术中的临床应用情况,综合评价新型骨水泥型椎弓根螺钉的安全性及可靠性。方法2009年1月至2013年5月,对227例合并骨质疏松的胸腰椎疾病患者进行后路椎板切除减压椎体间融合术,其中普通椎弓根螺钉组151例,男86例,女65例,平均年龄(71.4±6.7)岁;新型骨水泥型椎弓根螺钉组76例,男42例,女34例,平均年龄(73.1±7.0)岁。比较两组患者在手术时间、出血量、术后12个月疼痛视觉模拟评分( visual analogue scale, VAS )、Oswestry 功能障碍指数( oswestry disability index,ODI )以及螺钉松动率、椎间融合情况。结果骨水泥型椎弓根螺钉组无螺钉松动、断裂,所有病例获得椎体间植骨愈合;术后12个月的 VAS 和 ODI 评分分别为(2.0±0.5)分和(24.0±4.5),明显优于普通螺钉组的(1.7±0.5)分和(21.7±5.0),差异有统计学意义( P<0.05);普通椎弓根螺钉组出现26枚螺钉松动,松动率为3.3%。结论在骨质疏松腰椎内固定手术中,新型骨水泥型椎弓根螺钉较普通椎弓根螺钉具有更低的螺钉松动率,无骨水泥椎管内渗漏并发症,临床安全性高,近期效果满意,为骨质疏松患者手术提供了一种新型、可靠的内固定选择。%Objective To analyze clinical applications of traditional pedicle screws and cement-augmented pedicle screws in osteoporotic spine surgery, and to evaluate the safety and feasibility of novel cement-augmented pedicle screws.Methods From January, 2009 to May 2013, 227 cases of thoracolumbar spine diseases combined with osteoporosis were enrolled and underwent posterior laminectomy decompression and lumbar interbody fusion. One hundred and fifty-one cases received traditional pedicle screws ( 86 males, 65 females, the mean age: 71.4± 6.7 years ). Seventy-six cases received cement

  4. Enamel fluoride levels after orthodontic band cementation with glass ionomer cement.

    Science.gov (United States)

    Akkaya, S; Uner, O; Alaçam, A; Değim, T

    1996-02-01

    The aim of this investigation was to examine the fluoride uptake by enamel after application of glass ionomer cement for orthodontic band cementation compared with zinc phosphate cement. The study was conducted on 21 children whose mean age was 14 years. All the children were reared in the Middle Anatolian cities where the water fluoride concentration was below the level of 0.50 ppm. The subjects were randomly divided into three groups. The first experimental group, had seven subjects whose teeth were topically fluoridated with 2 per cent NaF solution, before orthodontic band cementation with zinc phosphate cement. The second experimental group also had seven subjects whose orthodontic bands were cemented with glass ionomer cement. The third group, consisted of seven control subjects and no dental procedures were performed in this group. All the participants were followed for 3 months and at the end of this period maxillary first premolars, which were in the ninth developmental stage according to Nolla (1960), were extracted for orthodontic purposes. The enamel fluoride concentrations were determined on the left maxillary first premolars at three successive etch depths by means of a fluor ion electrode, whereas the calcium concentrations were determined with an atomic absorption spectrophotometer. The results of this investigation showed that in both cementation groups enamel fluoride concentrations at three successive etch depths were highly increased compared with the control group. However, the difference between the cementation groups was not statistically significant. PMID:8746180

  5. Exposure to cement dust at a Portland cement factory and the risk of cancer.

    OpenAIRE

    Vestbo, J; Knudsen, K.M.; Raffn, E; Korsgaard, B; Rasmussen, F V

    1991-01-01

    The relation between exposure to cement dust and cancer was examined in a population of 546 cement workers and a reference population of 858 randomly sampled men of similar age and area of residence. In 1974 all men gave lifelong occupational and smoking histories; information on incidence of cancer in the period 1974-85 was obtained from the Danish Cancer Registry. No increased risk of overall cancer was found among cement workers. Among men with more than 20 years exposure to cement dust, 1...

  6. INFLUENCE OF WINE ACID ON RHEOLOGICAL PROPERTIES OF WELL BORE CEMENT SLURRIES AND HARDENED CEMENT PROPERTIES

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1989-12-01

    Full Text Available Adaptation of commercial types of domestic cements for use in cementing the deep wells is a process by which Yugoslav oil industry tends to solve problems of completion of those wells independently. In order to design a domestic, cheep and effective retarder, tests of applicability of wine acid on cement slurries have been carried out. Besides examining the necessary wine acid content to achieve desirable Theological properties, the influence of this additive on properties of hardened cement samples has been tested too (the paper is published in Croatian.

  7. Cementation of radioactive liquid scintillator waste simulate

    International Nuclear Information System (INIS)

    Liquid scintillation counting is an important analytical tool with extensive applications in medicine and basic applied research and used in quantification of □ -particles, weak □ and x-rays. The generated spent liquid scintillator radioactive waste should be limited and controlled to protect man and his environment. In this study, the radioactive spent liquid scintillator waste simulate (SLS) was immobilized in cement matrix using a surfactant in order to facilitate and increase the amount of SLS incorporated into the cementitious materials. Mechanical properties of the final cement waste form were acceptable for blocks containing up to 20% SLS in presence of surfactant. X-ray diffraction, IR analysis and scanning electron microscope proved that the hydration of cement materials is not significantly affected by organic scintillator waste. Therefore, the cement matrix could be recommended for solidification of SLS for the acceptable mechanical, physical and chemical characterizations reached.

  8. Calcium phosphate cements properties with polymers addition

    International Nuclear Information System (INIS)

    Calcium phosphate cements (CPC) have attracted great interest to use in orthopedics and dentistry as replacements for damaged parts of the skeletal system, showing good biocompatibility and osseointegration, allowing its use as bone graft. Several studies have shown that the addition of polymer additives have a strong influence on the cement properties. The low mechanical strength is the main obstacle to greater use of CPC as an implant material. The objective of this study was to evaluate properties of a cement based on α-tricalcium phosphate (α-TCP), added polymers. PVA (10%, 8%, 6%), sodium alginate (2%) and polyacrylate ammonia (3%), all in weight, were added to the synthesized α-TCP powder. The samples were molded and evaluated for density, porosity in vitro test (Simulated Body Fluid), crystalline phases and mechanical strength. The results show increased the mechanical properties of the cement when added these polymers

  9. Release of cetyl pyridinium chloride from fatty acid chelate temporary dental cement

    Science.gov (United States)

    Hurt, Andrew; Coleman, Nichola J.; Tüzüner, Tamer; Bagis, Bora; Korkmaz, Fatih Mehmet; Nicholson, John W.

    2016-01-01

    Abstract Objective To determine whether the antimicrobial nature of a fatty acid chelate temporary dental cement can be enhanced by the addition of 5% cetyl pyridinium chloride (CPC). Materials and methods The temporary cement, Cavex Temporary was employed, and additions of CPC were made to either the base or the catalyst paste prior to mixing the cement. Release of CPC from set cement specimens was followed using reverse-phase HPLC for a period of up to 2 weeks following specimen preparation. Potential interactions between Cavex and CPC were examined by Fourier transform infrared spectroscopy (FTIR) and antimicrobial effects were determined using zone of inhibition measurements after 24 h with disc-shaped specimens in cultured Streptococcus mutans. Results FTIR showed no interaction between CPC and the components of the cement. CPC release was found to follow a diffusion mechanism for the first 6 h or so, and to equilibrate after approximately 2 weeks, with no significant differences between release profiles when the additive was incorporated into the base or the catalyst paste. Diffusion was rapid, and had a diffusion coefficient of approximately 1 × 10−9 m2 s−1 in both cases. Total release was in the range 10–12% of the CPC loading. Zones of inhibition around discs containing CPC were significantly larger than those around the control discs of CPC-free cement. Conclusions The antimicrobial character of this temporary cement can be enhanced by the addition of CPC. Such enhancement is of potential clinical value, though further in vivo work is needed to confirm this. PMID:27335898

  10. Thyroid stem cells – danger or resource?

    OpenAIRE

    GIBELLI, B.; El-Fattah, AMA; Giugliano, G; PROH, M.; GROSSO, E.

    2009-01-01

    The thyroid gland has long since been known for its self-renewal ability, mainly in cases of hyperplastic disease such as goitre. Recently the amazing improvement in knowledge about stem cells has explained this potentiality. Some stem cell features and their clinical usefulness are summarized here, reviewing data from the literature: the proven presence of adult stem cells in thyroid tissue, either normal, goitrous or neoplastic, bring with it important implications regarding tissue regenera...

  11. Stem Cells

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2004-01-01

    In his influential essay on markets, An essay on framing and overflowing (1998), Michel Callon writes that `the growing complexity of industrialized societies [is] due in large part to the movements of the technosciences, which are causing connections and interdependencies to proliferate'. This p...... and tantalizing than stem cells, in research, in medicine, or as products.......'. This paper is about tech-noscience, and about the proliferation of connections and interdependencies created by it.More specifically, the paper is about stem cells. Biotechnology in general has the power to capture the imagination. Within the field of biotechnology nothing seems more provocative...

  12. Improvement of Cement Strength by Induction Method

    Institute of Scientific and Technical Information of China (English)

    YANG Li-yuan; LIN Zong-shou

    2004-01-01

    The induction method of improving the strength of Portland cement by adding fine slag powder,high aluminate component and hydrated paste was investigated through determining the physical properties,hydration heat and pore size distribution,and its mechanism was discussed.The experimental results reveal that a certain content of high aluminate component,fine slag powder and hydrated paste can improve remarkably the strength of Portland cement.

  13. Study and Characterization of Expansive Cement

    Directory of Open Access Journals (Sweden)

    Hugo Guerra Menéndez

    2011-10-01

    Full Text Available The objective of this study is to characterize commercial expansive cement for subsequent development of national formulation, with consequent economic effect and independence of the international market. On the other hand the results contribute to the development of scientific and technological potential. Expansive cement is a product that enables non-explosive demolition, rock and concrete demolition. To characterize the composition of these products, techniques used infrared spectroscopy with Fourier Transforms and Scanning Electron Microscopy.

  14. Study and Characterization of Expansive Cement

    OpenAIRE

    Hugo Guerra Menéndez; Eduardo Peón Avés; Julio E. Lanza Rodríguez

    2011-01-01

    The objective of this study is to characterize commercial expansive cement for subsequent development of national formulation, with consequent economic effect and independence of the international market. On the other hand the results contribute to the development of scientific and technological potential. Expansive cement is a product that enables non-explosive demolition, rock and concrete demolition. To characterize the composition of these products, techniques used infrared spectroscopy w...

  15. Radiological changes in asbestos cement workers.

    OpenAIRE

    Jakobsson, K; Strömberg, U; Albin, M; Welinder, H; Hagmar, L

    1995-01-01

    OBJECTIVE--To explore associations between exposure to asbestos cement dust and radiographic findings in lung parenchyma and pleura. METHODS--Radiographs from 174 blue collar workers and 29 white collar workers from an asbestos cement plant formed one part of the study. Progression of small opacities was further studied in those 124 blue collar workers, for whom two radiographs taken after the end of employment were available. The median readings from five readers who used the full ILO 1980 c...

  16. Dynamic properties of composite cemented clay

    Institute of Scientific and Technical Information of China (English)

    蔡袁强; 梁旭

    2004-01-01

    In this work,the dynamic properties of composite cemented clay under a wide range of strains were studied considering the effect of different mixing ratio and the change of confining pressures through dynamic triaxial test. A simple and practical method to estimate the dynamic elastic modulus and damping ratio is proposed in this paper and a related empirical normalized formula is also presented. The results provide useful guidelines for preliminary estimation of cement requirements to improve the dynamic properties of clays.

  17. Influence of polysaccharides on cement hydration

    OpenAIRE

    Peschard, Arnaud; Govin, Alexandre; Fredon, Emmanuel; Grosseau, Philippe; Fantozzi, Gilles

    2004-01-01

    This paper is about the influence of polysaccharides on cement hydration. Three polysaccharides were studied: a cellulose ether (CE), a starch ether (SE) and a dextrin (YD). In a concentrated media as well as in a dilute media, admixture CE only revealed a slight effect on cement hydration. Portlandite and ettringite formation and gypsum consumption were slowed down by SE adjunction. Admixture YD induced an acceleration of ettringite formation as well as gypsum consumption whereas portiandite...

  18. Microstructure Analysis of Heated Portland Cement Paste

    OpenAIRE

    Q. Zhang; Ye, G.

    2011-01-01

    When a concrete structure is exposed to high temperature, the mechanical damage and chemical transformation take place simultaneously, which will change the microstructure of material. On the other hand, the mechanical properties and transport properties depend on the development of microstructure of cement paste. In order to study the microstructure changes at high temperature, in this contribution the cement paste samples were firstly heated to varied temperatures from 100 °C to 1000 °C wit...

  19. Acrylic Bone Cements Modified with Starch

    OpenAIRE

    Krilova, V; Vītiņš, V

    2010-01-01

    The successful result of restorative and replacement surgical operation depends significantly on properties of used bone cement. Acrylic bone cements are usually based on methylmethacrylate polymer, while monomer polymerization begins after mixing of components in mixing device and terminates in living tissue. Polymerization of methylmethacrylate is exothermic process, and temperature increase might cause tissue necrosis with concomitant implant aseptic loosening. Developed non-ionogenic and ...

  20. Estimating the chloride transport in cement paste

    OpenAIRE

    Princigallo, A.

    2012-01-01

    A method was developed to measure the diffusion coefficient of chloride ions in cement paste based on an analytical solution to Fick’s 2nd law in a cylindrical coordinate system. This natural method yielded diffusivity results within as little as a month. Testing time was reduced by exploiting the three-dimensional inward flux in the specimen. In an attempt to determine the saturation concentration, dense portland cement pastes were exposed to a concentrated chloride solution. The method prov...