Science.gov

Sample records for bone potential applications

  1. Nanoparticles and their potential for application in bone

    PubMed Central

    Tautzenberger, Andrea; Kovtun, Anna; Ignatius, Anita

    2012-01-01

    Biomaterials are commonly applied in regenerative therapy and tissue engineering in bone, and have been substantially refined in recent years. Thereby, research approaches focus more and more on nanoparticles, which have great potential for a variety of applications. Generally, nanoparticles interact distinctively with bone cells and tissue, depending on their composition, size, and shape. Therefore, detailed analyses of nanoparticle effects on cellular functions have been performed to select the most suitable candidates for supporting bone regeneration. This review will highlight potential nanoparticle applications in bone, focusing on cell labeling as well as drug and gene delivery. Labeling, eg, of mesenchymal stem cells, which display exceptional regenerative potential, makes monitoring and evaluation of cell therapy approaches possible. By including bioactive molecules in nanoparticles, locally and temporally controlled support of tissue regeneration is feasible, eg, to directly influence osteoblast differentiation or excessive osteoclast behavior. In addition, the delivery of genetic material with nanoparticulate carriers offers the possibility of overcoming certain disadvantages of standard protein delivery approaches, such as aggregation in the bloodstream during systemic therapy. Moreover, nanoparticles are already clinically applied in cancer treatment. Thus, corresponding efforts could lead to new therapeutic strategies to improve bone regeneration or to treat bone disorders. PMID:22923992

  2. Preparation of Laponite Bioceramics for Potential Bone Tissue Engineering Applications

    PubMed Central

    Li, Kai; Ju, Yaping; Li, Jipeng; Zhang, Yongxing; Li, Jinhua; Liu, Xuanyong; Shi, Xiangyang; Zhao, Qinghua

    2014-01-01

    We report a facile approach to preparing laponite (LAP) bioceramics via sintering LAP powder compacts for bone tissue engineering applications. The sintering behavior and mechanical properties of LAP compacts under different temperatures, heating rates, and soaking times were investigated. We show that LAP bioceramic with a smooth and porous surface can be formed at 800°C with a heating rate of 5°C/h for 6 h under air. The formed LAP bioceramic was systematically characterized via different methods. Our results reveal that the LAP bioceramic possesses an excellent surface hydrophilicity and serum absorption capacity, and good cytocompatibility and hemocompatibility as demonstrated by resazurin reduction assay of rat mesenchymal stem cells (rMSCs) and hemolytic assay of pig red blood cells, respectively. The potential bone tissue engineering applicability of LAP bioceramic was explored by studying the surface mineralization behavior via soaking in simulated body fluid (SBF), as well as the surface cellular response of rMSCs. Our results suggest that LAP bioceramic is able to induce hydroxyapatite deposition on its surface when soaked in SBF and rMSCs can proliferate well on the LAP bioceramic surface. Most strikingly, alkaline phosphatase activity together with alizarin red staining results reveal that the produced LAP bioceramic is able to induce osteoblast differentiation of rMSCs in growth medium without any inducing factors. Finally, in vivo animal implantation, acute systemic toxicity test and hematoxylin and eosin (H&E)-staining data demonstrate that the prepared LAP bioceramic displays an excellent biosafety and is able to heal the bone defect. Findings from this study suggest that the developed LAP bioceramic holds a great promise for treating bone defects in bone tissue engineering. PMID:24955961

  3. Stem cell technology for bone regeneration: current status and potential applications.

    PubMed

    Asatrian, Greg; Pham, Dalton; Hardy, Winters R; James, Aaron W; Peault, Bruno

    2015-01-01

    Continued improvements in the understanding and application of mesenchymal stem cells (MSC) have revolutionized tissue engineering. This is particularly true within the field of skeletal regenerative medicine. However, much remains unknown regarding the native origins of MSC, the relative advantages of different MSC populations for bone regeneration, and even the biologic safety of such unpurified, grossly characterized cells. This review will first summarize the initial discovery of MSC, as well as the current and future applications of MSC in bone tissue engineering. Next, the relative advantages and disadvantages of MSC isolated from distinct tissue origins are debated, including the MSC from adipose, bone marrow, and dental pulp, among others. The perivascular origin of MSC is next discussed. Finally, we briefly comment on pluripotent stem cell populations and their possible application in bone tissue engineering. While continually expanding, the field of MSC-based bone tissue engineering and regeneration shows potential to become a clinical reality in the not-so-distant future. PMID:25709479

  4. In vitro evaluation of osteoprotegerin in chitosan for potential bone defect applications

    PubMed Central

    Misran, Misni; Baharuddin, NA

    2016-01-01

    Background The receptor activator of nuclear factor kappa-B (RANK)/RANK ligand/osteoprotegerin (OPG) system plays a critical role in bone remodelling by regulating osteoclast formation and activity. OPG has been used systemically in the treatment of bone diseases. In searching for more effective and safer treatment for bone diseases, we investigated newly formulated OPG-chitosan complexes, which is prepared as a local application for its osteogenic potential to remediate bone defects. Methods We examined high, medium and low molecular weights of chitosan combined with OPG. The cytotoxicity of OPG in chitosan and its proliferation in vitro was evaluated using normal, human periodontal ligament (NHPL) fibroblasts in 2D and 3D cell culture. The cytotoxicity of these combinations was compared by measuring cell survival with a tetrazolium salt reduction (MTT) assay and AlamarBlue assay. The cellular morphological changes were observed under an inverted microscope. A propidium iodide and acridine orange double-staining assay was used to evaluate the morphology and quantify the viable and nonviable cells. The expression level of osteopontin and osteocalcin protein in treated normal human osteoblast cells was evaluated by using Western blot. Results The results demonstrated that OPG in combination with chitosan was non-toxic, and OPG combined with low molecular weight chitosan has the most significant effect on NHPL fibroblasts and stimulates proliferation of cells over the period of treatment.

  5. Carboxymethyl cellulose enables silk fibroin nanofibrous scaffold with enhanced biomimetic potential for bone tissue engineering application.

    PubMed

    Singh, B N; Panda, N N; Mund, R; Pramanik, K

    2016-10-20

    Novel silk fibroin (SF) and carboxymethyl cellulose (CMC) composite nanofibrous scaffold (SFC) were developed to investigate their ability to nucleate bioactive nanosized calcium phosphate (Ca/P) by biomineralization for bone tissue engineering application. The composite nanofibrous scaffold was prepared by free liquid surface electrospinning method. The developed composite nanofibrous scaffold was observed to control the size of Ca/P particle (≤100nm) as well as uniform nucleation of Ca/P over the surface. The obtained nanofibrous scaffolds were fully characterized for their functional, structural and mechanical property. The XRD and EDX analysis depicted the development of apatite like crystals over SFC scaffolds of nanospherical in morphology and distributed uniformly throughout the surface of scaffold. Additionally, hydrophilicity as a measure of contact angle and water uptake capacity is higher than pure SF scaffold representing the superior cell supporting property of the SF/CMC scaffold. The effect of biomimetic Ca/P on osteogenic differentiation of umbilical cord blood derived human mesenchymal stem cells (hMSCs) studied in early and late stage of differentiation shows the improved osteoblastic differentiation capability as compared to pure silk fibroin. The obtained result confirms the positive correlation of alkaline phosphatase activity, alizarin staining and expression of runt-related transcription factor 2, osteocalcin and type1 collagen representing the biomimetic property of the scaffolds. Thus, the developed composite has been demonstrated to be a potential scaffold for bone tissue engineering application. PMID:27474575

  6. The Potential Application of Pulsed Ultrasound on Bone Defect Repair via Developmental Engineering: An In Vitro Study.

    PubMed

    Wang, Jue; Tang, Na; Xiao, Qiang; Zhao, Lixing; Li, Yu; Li, Juan; Wang, Jun; Zhao, Zhihe; Tan, Lijun

    2016-05-01

    Repairing bone defect by recapitulation of endochondral bone formation, known as developmental engineering, has been a promising approach in bone tissue engineering. The critical issue in this area is how to effectively construct the hypertrophic cartilaginous template in vitro and enhance in vivo endochondral ossification process after implantation. Pulsed ultrasound stimulation has been widely used in the clinic for accelerating bone healing in fractures and nonunions. The aim of this study was to investigate whether ultrasound (US) could accelerate in vitro chondrogenesis and the hypertrophic process in certain microenvironments. Rat bone marrow mesenchymal stem cells were chondrogenic or hypertrophic differentiated in a three-dimensional pellet culture system with different media, and treated with different intensities of US. US exposure promoted chondrogenic differentiation of stem cells and inhibited their transition into the hypertrophic stage in a chondrogenic-friendly microenvironment. US significantly advanced hypertrophic differentiation of bone marrow stem cell pellets in hypertrophic medium after chondrogenesis. Our data indicated that pulsed US promoted in vitro chondrogenic and hypertrophic differentiation of stem cell pellets in specific culture conditions. The present study proves the potential application of US in the in vitro stage of "developmental engineering" for bone development and repair. PMID:26526417

  7. Hierarchical Structure of Articular Bone-Cartilage Interface and Its Potential Application for Osteochondral Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Bian, Weiguo; Qin, Lian; Li, Dichen; Wang, Jin; Jin, Zhongmin

    2010-09-01

    The artificial biodegradable osteochondral construct is one of mostly promising lifetime substitute in the joint replacement. And the complex hierarchical structure of natural joint is important in developing the osteochondral construct. However, the architecture features of the interface between cartilage and bone, in particular those at the micro-and nano-structural level, remain poorly understood. This paper investigates these structural data of the cartilage-bone interface by micro computerized tomography (μCT) and Scanning Electron Microscope (SEM). The result of μCT shows that important bone parameters and the density of articular cartilage are all related to the position in the hierarchical structure. The conjunctions of bone and cartilage were defined by SEM. All of the study results would be useful for the design of osteochondral construct further manufactured by nano-tech. A three-dimensional model with gradient porous structure is constructed in the environment of Pro/ENGINEERING software.

  8. Development of model hydroxyapatite bone scaffolds with multiscale porosity for potential load bearing applications

    NASA Astrophysics Data System (ADS)

    Dellinger, Jennifer Gwynne

    2005-11-01

    Model hydroxyapatite (HA) bone scaffolds consisting of a latticed pattern of rods were fabricated by a solid freeform fabrication (SFF) technique based on the robotic deposition of colloidal pastes. An optimal HA paste formulation for this method was developed. Local porosity, i.e. microporosity (1--30 mum) and sintering porosity (less than 1 mum), were produced by including polymer microsphere porogens in the HA pastes and by controlling the sintering of the scaffolds. Scaffolds with and without local porosity were evaluated with and without in vitro accelerated degradation. Percent weight loss of the scaffolds and calcium and phosphorus concentrations in solution increased with degradation time. After degradation, compressive strength and modulus decreased significantly for scaffolds with local porosity, but did not change significantly for scaffolds without local porosity. The compressive strength and modulus of scaffolds without local porosity were comparable to human cortical bone and were significantly greater than the scaffolds with local porosity. Micropores in HA disks caused surface pits that increased the surface roughness as compared to non-microporous HA disks. Mouse mesenchymal stem cells extended their cell processes into these microporous pits on HA disks in vitro. ALP expression was prolonged, cell attachment strength increased, and ECM production appeared greater on microporous HA disks compared to non-microporous HA disks and tissue culture treated polystyrene controls. Scaffolds with and without microporosity were implanted in goats bones. Microporous scaffolds with rhBMP-2 increased the percent of the scaffold filled with bone tissue compared to microporous scaffolds without rhBMP-2. Lamellar bone inside scaffolds was aligned near the rods junctions whereas lamellar bone was aligned in a more random configuration away from the rod junctions. Microporous scaffolds stained darkly with toluidine blue beneath areas of contact with new bone. This

  9. Fabrication of an integrated cartilage/bone joint prosthesis and its potential application in joint replacement.

    PubMed

    Hou, Yi; Chen, Chen; Zhou, Song; Li, Yubao; Wang, Danqing; Zhang, Li

    2016-06-01

    An integrated cartilage/bone joint prosthesis was designed and fabricated using a two-step molding injection method, in which ethylene-vinyl acetate copolymer (EVA) was used as the upper cartilage layer, and hydroxyapatite/polyamide66 (HA/PA66) composites as the underlying bone layer. Holes punched in the underlying layer improved the interfacial bonding strength between the two layers by means of the mechanical interlocking obviously. Then, the physicochemical properties and in vivo behaviors of the integrated joint prosthesis were investigated. The results showed that the upper layer displayed good bio-tribological properties which were suitable for the articular cartilage replacement, while the underlying layer demonstrated good mechanical performance, excellent biocompatibility and high bioactivity, and could accelerate bone regeneration and the early bio-fixation of the prosthesis. Therefore, the prosthesis prepared here will have a wide prospect to be used in joint replacement. PMID:26889776

  10. Potential of Magnetic Nanofiber Scaffolds with Mechanical and Biological Properties Applicable for Bone Regeneration

    PubMed Central

    Singh, Rajendra K.; Patel, Kapil D.; Lee, Jae Ho; Lee, Eun-Jung; Kim, Joong-Hyun; Kim, Tae-Hyun; Kim, Hae-Won

    2014-01-01

    Magnetic nanofibrous scaffolds of poly(caprolactone) (PCL) incorporating magnetic nanoparticles (MNP) were produced, and their effects on physico-chemical, mechanical and biological properties were extensively addressed to find efficacy for bone regeneration purpose. MNPs 12 nm in diameter were citrated and evenly distributed in PCL solutions up to 20% and then were electrospun into nonwoven nanofibrous webs. Incorporation of MNPs greatly improved the hydrophilicity of the nanofibers. Tensile mechanical properties of the nanofibers (tensile strength, yield strength, elastic modulus and elongation) were significantly enhanced with the addition of MNPs up to 15%. In particular, the tensile strength increase was as high as ∼25 MPa at 15% MNPs vs. ∼10 MPa in pure PCL. PCL-MNP nanofibers exhibited magnetic behaviors, with a high saturation point and hysteresis loop area, which increased gradually with MNP content. The incorporation of MNPs substantially increased the degradation of the nanofibers, with a weight loss of ∼20% in pure PCL, ∼45% in 10% MNPs and ∼60% in 20% MNPs. Apatite forming ability of the nanofibers tested in vitro in simulated body fluid confirmed the substantial improvement gained by the addition of MNPs. Osteoblastic cells favored the MNPs-incorporated nanofibers with significantly improved initial cell adhesion and subsequent penetration through the nanofibers, compared to pure PCL. Alkaline phosphatase activity and expression of genes associated with bone (collagen I, osteopontin and bone sialoprotein) were significantly up-regulated in cells cultured on PCL-MNP nanofibers than those on pure PCL. PCL-MNP nanofibers subcutaneously implanted in rats exhibited minimal adverse tissue reactions, while inducing substantial neoblood vessel formation, which however, greatly limited in pure PCL. In vivo study in radial segmental defects also signified the bone regeneration ability of the PCL-MNP nanofibrous scaffolds. The magnetic, bone

  11. Silver nanoparticle based antibacterial methacrylate hydrogels potential for bone graft applications

    PubMed Central

    González-Sánchez, M. Isabel; Perni, Stefano; Tommasi, Giacomo; Morris, Nathanael Glyn; Hawkins, Karl; López-Cabarcos, Enrique; Prokopovich, Polina

    2015-01-01

    Infections are frequent and very undesired occurrences after orthopedic procedures; furthermore, the growing concern caused by the rise in antibiotic resistance is progressively dwindling the efficacy of such drugs. Artificial bone graft materials could solve some of the problems associated with the gold standard use of natural bone graft such as limited bone material, pain at the donor site and rejections if donor tissue is used. We have previously described new acrylate base nanocomposite hydrogels as bone graft materials. In the present paper, we describe the integration of silver nanoparticles in the polymeric mineralized biomaterial to provide non-antibiotic antibacterial activity against Staphylococcus epidermidis and Methicillin-resistant Staphylococcus aureus. Two different crosslinking degrees were tested and the silver nanoparticles were integrated into the composite matrix by means of three different methods: entrapment in the polymeric hydrogel before the mineralization; diffusion during the process of calcium phosphate crystallization and adsorption post-mineralization. The latter being generally the most effective method of encapsulation; however, the adsorption of silver nanoparticles inside the pores of the biomaterial led to a decreasing antibacterial activity for adsorption time longer than 2 days. PMID:25746278

  12. Silver nanoparticle based antibacterial methacrylate hydrogels potential for bone graft applications.

    PubMed

    González-Sánchez, M Isabel; Perni, Stefano; Tommasi, Giacomo; Morris, Nathanael Glyn; Hawkins, Karl; López-Cabarcos, Enrique; Prokopovich, Polina

    2015-05-01

    Infections are frequent and very undesired occurrences after orthopedic procedures; furthermore, the growing concern caused by the rise in antibiotic resistance is progressively dwindling the efficacy of such drugs. Artificial bone graft materials could solve some of the problems associated with the gold standard use of natural bone graft such as limited bone material, pain at the donor site and rejections if donor tissue is used. We have previously described new acrylate base nanocomposite hydrogels as bone graft materials. In the present paper, we describe the integration of silver nanoparticles in the polymeric mineralized biomaterial to provide non-antibiotic antibacterial activity against Staphylococcus epidermidis and Methicillin-resistant Staphylococcus aureus. Two different crosslinking degrees were tested and the silver nanoparticles were integrated into the composite matrix by means of three different methods: entrapment in the polymeric hydrogel before the mineralization; diffusion during the process of calcium phosphate crystallization and adsorption post-mineralization. The latter being generally the most effective method of encapsulation; however, the adsorption of silver nanoparticles inside the pores of the biomaterial led to a decreasing antibacterial activity for adsorption time longer than 2 days. PMID:25746278

  13. Piezoelectric Bone Surgery: A Review of the Literature and Potential Applications in Veterinary Oromaxillofacial Surgery

    PubMed Central

    Hennet, Philippe

    2015-01-01

    Piezoelectric bone surgery is a recent and innovative technology, permitting a selective cut of mineralized tissue while sparing soft tissue. Similar to a dental scaler, a high frequency vibration, in the range of 25–35 kHz, is transmitted to a metallic tip. However, the power of the piezosurgical instrument is three to six times higher than that of a dental scaler. The major advantages of this technology include high precision, a design that increases ease of curvilinear osteotomy, less trauma to soft tissue, preservation of neurological and vascular structures, reduced hemorrhage, minimal thermal damage to the bone, as well as overall improvement of healing. The handpiece of the instrument is equipped with a sterile irrigation system and light-emitting diode (LED) light, which improves visibility and overall safety. Piezoelectric surgery is particularly useful when performing delicate bone procedures such as periodontal or endodontic surgery. It is also indicated when performing more invasive bone surgery such as maxillectomy, mandibulectomy, and condylectomy, where preservation of neurovascular structures is important. Piezoelectric instruments are different from rotary instrumentation or oscillating saws, they require light pressure with constant motion of the tip. Training is required to master the technique. PMID:26664937

  14. Tailoring the degradation and biological response of a magnesium-strontium alloy for potential bone substitute application.

    PubMed

    Han, Junjie; Wan, Peng; Ge, Ye; Fan, Xinmin; Tan, Lili; Li, Jianjun; Yang, Ke

    2016-01-01

    Bone defects are very challenging in orthopedic practice. There are many practical and clinical shortcomings in the repair of the defect by using autografts, allografts or xenografts, which continue to motivate the search for better alternatives. The ideal bone grafts should provide mechanical support, fill osseous voids and enhance the bone healing. Biodegradable magnesium-strontium (Mg-Sr) alloys demonstrate good biocompatibility and osteoconductive properties, which are promising biomaterials for bone substitutes. The aim of this study was to evaluate and pair the degradation of Mg-Sr alloys for grafting with their clinical demands. The microstructure and performance of Mg-Sr alloys, in vitro degradation and biological properties including in vitro cytocompatibility and in vivo implantation were investigated. The results showed that the as-cast Mg-Sr alloy exhibited a rapid degradation rate compared with the as-extruded alloy due to the intergranular distribution of the second phase and micro-galvanic corrosion. However, the initial degradation could be tailored by the coating protection, which was proved to be cytocompatible and also suitable for bone repair observed by in vivo implantation. The integrated fracture calluses were formed and bridged the fracture gap without gas bubble accumulation, meanwhile the substitutes simultaneously degraded. In conclusion, the as-cast Mg-Sr alloy with coating is potential to be used for bone substitute alternative. PMID:26478374

  15. The processing and characterization of animal-derived bone to yield materials with biomedical applications. Part II: milled bone powders, reprecipitated hydroxyapatite and the potential uses of these materials.

    PubMed

    Johnson, G S; Mucalo, M R; Lorier, M A; Gieland, U; Mucha, H

    2000-11-01

    Further studies on the processing and use of animal-bone-derived calcium phosphate materials in biomedical applications are presented. Bone powders sourced either from the direct crushing and milling of bovine, ovine and cervine bone or after being subjected to defatting and acid digestion/NaOH reprecipitation and sodium hypochlorite hydrogen peroxide treatment of animal bones were characterized using Fourier transform infra-red (FTIR) spectroscopy, 13C solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, atomic absorption (AA) and inductively coupled plasma (ICP) spectrometric techniques. Bone powders were trialled for their potential use as a substrate for phosphine coupling and enzyme immobilization as well as a feedstock powder for plasma spraying on titanium metal substrates. Results indicated that enzyme immobilization by phosphine coupling could be successfully achieved on milled cervine bone with the immobilized enzyme retaining some activity. It was found that the presence of impurities normally carried down with the processing of the bone materials (viz., fat and collagen) played an important role in influencing the adsorbency and reactivity of the powders. Plasma spraying studies using reprecipitated bovine-derived powders produced highly adherent coatings on titanium metal, the composition of which was mostly hydroxyapatite (Ca10(PO4)6(OH)2) with low levels of alpha-tricalcium phosphate (alpha-Ca3(PO4)2) and tetracalcium phosphate (Ca4P2O9) also detected. In general, animal derived calcium phosphate materials constitute a potentially cheaper source of calcium phosphate materials for biomedical applications and make use of a largely under-utilized resource from abattoir wastes. PMID:15348079

  16. Reengineered graft copolymers as a potential alternative for the bone tissue engineering application by inducing osteogenic markers expression and biocompatibility.

    PubMed

    Thangavelu, Muthukumar; R Narasimha, Raghavan; Adithan, Aravinthan; A, Chandrasekaran; Jong-Hoon, Kim; Thotapalli Parvathaleswara, Sastry

    2016-07-01

    Composite scaffolds of nano-hydroxyapatite with demineralized bone matrix were prepared and they were graft copolymerized for better bone regeneration and drug delivery applications. The graft copolymers were characterized for their physiochemical properties using conventional methods like FTIR, TGA, XRD and SEM. The scaffolds were seeded with 3T3 and MG63 cells for studying their biocompatibility and their temporal expression of ALP activity, the rate of calcium deposition and their gene expression of collagen type I (Coll-1), osteopontin (OP), osteonectin (ON), and osteocalcin (OC) were studied. In vivo studies were conducted using sub-cutaneous implantation models in male Wister rats for 6 months. Periodic radiography and post-autopsy histopathology was analysed at 15days, 1, 2, 3, 4, 5, and 6 months. The obtained in vitro results clearly confirm that the bone scaffolds prepared in this study are biocompatible, superior osteoinductivity, capable of supporting growth, maturation of MG 63 osteoblast like cells; the gene expression profile revealed that the material is capable of supporting the in vitro growth and maturation of osteoblast-like cells and maturation. The in vivo results stand a testimony to the in vitro results in proving the biocompatibility and osteoinductivity of the materials. PMID:26998863

  17. Prostaglandin E2: from clinical applications to its potential role in bone- muscle crosstalk and myogenic differentiation.

    PubMed

    Mo, Chenglin; Romero-Suarez, Sandra; Bonewald, Lynda; Johnson, Mark; Brotto, Marco

    2012-12-01

    Prostaglandin E(2) (PGE(2)), a prostanoid synthesized from arachidonic acid via the cyclooxygenase pathway, is a modulator of physiological responses including inflammation, fever, and muscle regeneration. Several patents have been filed that are related to PGE(2), one of them being directly related to skeletal muscles. In this report, we first summarize the key patents describing inventions for the utilization of PGE(2) for either diagnostic or therapeutic purposes, including skeletal muscle. In the second part of our work we present new and exciting data that demonstrates that PGE(2) accelerates skeletal muscle myogenic differentiation. Our discovery resulted from our recent and novel concept of bone-muscle crosstalk. Bone and muscle are anatomically intimate endocrine organs and we aimed to determine whether this anatomical intimacy also translates into a biochemical communication from bone cells to muscle cells at the in vitro level. The effects of MLOY4 osteocyte-like cell conditioned medium (CM) and three osteocyte-secreted factors, PGE(2), sclerostin and monocyte chemotactic protein (MCP-3), on C2C12 myogenic differentiation were evaluated using morphological analyses, a customized 96-gene PCR array, and measurements of intracellular calcium levels. MLO-Y4 CM and PGE(2), but not sclerostin and MCP-3, induced acceleration of myogenesis of C2C12 myoblasts that was linked with significant modifications in intracellular calcium homeostasis. This finding should further stimulate the pursuit of new patents to explore the use of PGE(2) and the new concept of bone-muscle crosstalk for the development and application of inventions designed to treat muscle diseases characterized by enhanced muscle wasting, such as sarcopenia. PMID:23092433

  18. Prostaglandin E2: From clinical applications to its potential role in bone-muscle crosstalk and myogenic differentiation

    PubMed Central

    Mo, Chenglin; Romero-Suarez, Sandra; Bonewald, Lynda; Johnson, Mark; Brotto, Marco

    2013-01-01

    Prostaglandin E2 (PGE2), a prostanoid synthesized from arachidonic acid via the cyclooxygenase pathway, is a modulator of physiological responses including inflammation, fever, and muscle regeneration. Several patents have been filed that are related to PGE2, one of them being directly related to skeletal muscles. In this report, we first summarize the key patents describing inventions for the utilization of PGE2 for either diagnostic or therapeutic purposes, including skeletal muscle. In the second part of our work we present new and exciting data that demonstrates that PGE2 accelerates skeletal muscle myogenic differentiation. Our discovery resulted from our recent and novel concept of bone-muscle crosstalk. Bone and muscle are anatomically intimate endocrine organs and we aimed to determine whether this anatomical intimacy also translates into a biochemical communication from bone cells to muscle cells at the in vitro level. The effects of MLO-Y4 osteocyte-like cell conditioned medium (CM) and three osteocyte-secreted factors, PGE2, sclerostin and monocyte chemotactic protein (MCP-3), on C2C12 myogenic differentiation were evaluated using morphological analyses, a customized 96-PCR gene array, and measurements of intracellular calcium levels. MLO-Y4 CM and PGE2, but not sclerostin and MCP-3, induced acceleration of myogenesis of C2C12 myoblasts that was linked with significant modifications in intracellular calcium homeostasis. This finding should further stimulate the pursuit of new patents to explore the use of PGE2 and the new concept of bone-muscle crosstalk for the development and application of inventions designed to treat muscle diseases characterized by enhanced muscle wasting, such as sarcopenia. PMID:23092433

  19. Alveolar bone loss: mechanisms, potential therapeutic targets, and interventions.

    PubMed

    Intini, G; Katsuragi, Y; Kirkwood, K L; Yang, S

    2014-05-01

    This article reviews recent research into mechanisms underlying bone resorption and highlights avenues of investigation that may generate new therapies to combat alveolar bone loss in periodontitis. Several proteins, signaling pathways, stem cells, and dietary supplements are discussed as they relate to periodontal bone loss and regeneration. RGS12 is a crucial protein that mediates osteoclastogenesis and bone destruction, and a potential therapeutic target. RGS12 likely regulates osteoclast differentiation through regulating calcium influx to control the calcium oscillation-NFATc1 pathway. A working model for RGS10 and RGS12 in the regulation of Ca(2+) oscillations during osteoclast differentiation is proposed. Initiation of inflammation depends on host cell-microbe interactions, including the p38 mitogen-activated protein kinase (MAPK) signaling pathway. Oral p38 inhibitors reduced lipopolysaccharide (LPS)-induced bone destruction in a rat periodontitis model but showed unsatisfactory safety profiles. The p38 substrate MK2 is a more specific therapeutic target with potentially superior tolerability. Furthermore, MKP-1 shows anti-inflammatory activity, reducing inflammatory cytokine biosynthesis and bone resorption. Multipotent skeletal stem cell (SSC) populations exist within the bone marrow and periosteum of long bones. These bone-marrow-derived SSCs and periosteum-derived SSCs have shown therapeutic potential in several applications, including bone and periodontal regeneration. The existence of craniofacial bone-specific SSCs is suggested based on existing studies. The effects of calcium, vitamin D, and soy isoflavone supplementation on alveolar and skeletal bone loss in post-menopausal women were investigated. Supplementation resulted in stabilization of forearm bone mass density and a reduced rate of alveolar bone loss over 1 yr, compared with placebo. Periodontal attachment levels were also well-maintained and alveolar bone loss suppressed during 24 wk of

  20. Indirect selective laser sintering of an apatite-mullite glass-ceramic for potential use in bone replacement applications.

    PubMed

    Goodridge, R D; Dalgarno, K W; Wood, D J

    2006-01-01

    The feasibility of using indirect selective laser sintering (SLS) to produce parts from glass-ceramic materials for bone replacement applications has been investigated. A castable glass based on the system SiO2 x Al2O3 x P2O5 x CaO x CaF2 that crystallizes to a glass-ceramic with apatite and mullite phases was produced, blended with an acrylic binder, and processed by SLS. Green parts with good structural integrity were produced using a wide range of processing conditions, allowing both monolayer and multilayer components to be constructed. Following SLS the parts were post-processed to remove the binder and to crystallize fully the material, evolving the apatite and mullite phases. The parts were heated to 1200 degrees C using a number of different time-temperature profiles, following which the processed material was analysed by differential thermal analysis, X-ray diffraction, and scanning electron microscopy, and tested for flexural strength. An increase in strength was achieved by infiltrating the brown parts with a resorbable phosphate glass, although this altered the crystal phases present in the material. PMID:16459446

  1. Human progenitor cells for bone engineering applications.

    PubMed

    de Peppo, G M; Thomsen, P; Karlsson, C; Strehl, R; Lindahl, A; Hyllner, J

    2013-06-01

    In this report, the authors review the human skeleton and the increasing burden of bone deficiencies, the limitations encountered with the current treatments and the opportunities provided by the emerging field of cell-based bone engineering. Special emphasis is placed on different sources of human progenitor cells, as well as their pros and cons in relation to their utilization for the large-scale construction of functional bone-engineered substitutes for clinical applications. It is concluded that, human pluripotent stem cells represent a valuable source for the derivation of progenitor cells, which combine the advantages of both embryonic and adult stem cells, and indeed display high potential for the construction of functional substitutes for bone replacement therapies. PMID:23642054

  2. Mechanical properties, biological behaviour and drug release capability of nano TiO2-HAp-Alginate composite scaffolds for potential application as bone implant material.

    PubMed

    Naik, Kshipra; Chandran, V Girish; Rajashekaran, Raghavan; Waigaonkar, Sachin; Kowshik, Meenal

    2016-09-01

    Nanocomposite scaffolds of TiO2 and hydroxyapatite nanoparticles with alginate as the binding agent were fabricated using the freeze drying technique. TiO2, hydroxyapatite and alginate were used in the ratio of 1:1:4. The scaffolds were characterized using X-ray diffraction, fourier transform infrared spectroscopy, and scanning electron microscopy. The biocompatibility of the scaffolds was evaluated using cell adhesion and MTT assay on osteosarcoma (MG-63) cells. Scanning electron microscopy analysis revealed that cells adhered to the surface of the scaffolds with good spreading. The mechanical properties of the scaffolds were investigated using dynamic mechanical analysis. The swelling ability, porosity, in vitro degradation, and biomineralization of the scaffolds were also evaluated. The results indicated controlled swelling, limited degradation, and enhanced biomineralization. Further, drug delivery studies of the scaffolds using the chemotherapeutic drug methotrexate exhibited an ideal drug release profile. These scaffolds are proposed as potential candidates for bone tissue engineering and drug delivery applications. PMID:27485954

  3. Investigation of potential injectable polymeric biomaterials for bone regeneration

    PubMed Central

    Dreifke, Michael B.; Ebraheim, Nabil A.; Jayasuriya, Ambalangodage C.

    2014-01-01

    This article reviews the potential injectable polymeric biomaterial scaffolds currently being investigated for application in bone tissue regeneration. Two types of injectable biomaterial scaffolds are focused in this review, including injectable microspheres and injectable gels. The injectable microspheres section covers several polymeric materials, including poly(l-lactide-co-glycolide)-PLGA, poly (propylene fumarate), and chitosan. The injectable gel section covers alginate gels, hyaluronan hydrogels, poly(ethylene-glycol)-PEG hydrogels, and PEG-PLGA copolymer hydrogels. This review focuses on the effect of cellular behaviorin vitro andin vivo in terms of material properties of polymers, such as biodegradation, biocompatibility, porosity, microsphere size, and cross-linking nature. Injectable polymeric biomaterials offer a major advantage for orthopedic applications by allowing the ability to use noninvasive or minimally invasive treatment methods. Therefore, combining injectable polymeric biomaterial scaffolds with cells have a significant potential to treat orthopedic bone defects, including spine fusion, and craniofacial and periodontal defects. PMID:23401336

  4. Model to characterize strain generated potentials in bone.

    PubMed

    Mahmud, F A; Hastings, G W; Martini, M

    1988-01-01

    A model has been developed to characterize the strain generated potentials (SGPs) in bone. The model relates the SGP signal to the rotation (reorientation) of the spontaneous dipoles of bone in response to mechanical deformation. The effects of bone structural conditions and the measuring circuitry on the recorded potential are both accounted for by the model. PMID:3347035

  5. Preparation and characterization of polylactide/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) hybrid fibers for potential application in bone tissue engineering

    PubMed Central

    Wang, YueLong; Guo, Gang; Chen, HaiFeng; Gao, Xiang; Fan, RangRang; Zhang, DongMei; Zhou, LiangXue

    2014-01-01

    The aim of this study was to develop a kind of osteogenic biodegradable composite graft consisting of human placenta-derived mesenchymal stem cell (hPMSC) material for site-specific repair of bone defects and attenuation of clinical symptoms. The novel nano- to micro-structured biodegradable hybrid fibers were prepared by electrospinning. The characteristics of the hybrid membranes were investigated by a range of methods, including Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. Morphological study with scanning electron microscopy showed that the average fiber diameter and the number of nanoscale pores on each individual fiber surface decreased with increasing concentration of poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC). The prepared polylactide (PLA)/PCEC fibrous membranes favored hPMSC attachment and proliferation by providing an interconnected, porous, three-dimensional mimicked extracellular environment. What is more, hPMSCs cultured on the electrospun hybrid PLA/PCEC fibrous scaffolds could be effectively differentiated into bone-associated cells by positive alizarin red staining. Given the good cellular response and excellent osteogenic potential in vitro, the electrospun PLA/PCEC fibrous scaffolds could be one of the most promising candidates for bone tissue engineering. PMID:24790439

  6. Biomimetically enhanced demineralized bone matrix for bone regenerative applications

    PubMed Central

    Ravindran, Sriram; Huang, Chun-Chieh; Gajendrareddy, Praveen; Narayanan, Raghuvaran

    2015-01-01

    Demineralized bone matrix (DBM) is one of the most widely used bone graft materials in dentistry. However, the ability of DBM to reliably and predictably induce bone regeneration has always been a cause for concern. The quality of DBM varies greatly depending on several donor dependent factors and also manufacturing techniques. In order to standardize the quality and to enable reliable and predictable bone regeneration, we have generated a biomimetically-enhanced version of DBM (BE-DBM) using clinical grade commercial DBM as a control. We have generated the BE-DBM by incorporating a cell-derived pro-osteogenic extracellular matrix (ECM) within clinical grade DBM. In the present study, we have characterized the BE-DBM and evaluated its ability to induce osteogenic differentiation of human marrow derived stromal cells (HMSCs) with respect to clinical grade commercial DBM. Our results indicate that the BE-DBM contains significantly more pro-osteogenic factors than DBM and enhances HMSC differentiation and mineralized matrix formation in vitro and in vivo. Based on our results, we envision that the BE-DBM has the potential to replace DBM as the bone graft material of choice. PMID:26557093

  7. Distribution Atlas of Proliferating Bone Marrow in Non-Small Cell Lung Cancer Patients Measured by FLT-PET/CT Imaging, With Potential Applicability in Radiation Therapy Planning

    SciTech Connect

    Campbell, Belinda A.; Callahan, Jason; Bressel, Mathias; Simoens, Nathalie; Everitt, Sarah; Hofman, Michael S.; Hicks, Rodney J.; Burbury, Kate; MacManus, Michael

    2015-08-01

    Purpose: Proliferating bone marrow is exquisitely sensitive to ionizing radiation. Knowledge of its distribution could improve radiation therapy planning to minimize unnecessary marrow exposure and avoid consequential prolonged myelosuppression. [18F]-Fluoro-3-deoxy-3-L-fluorothymidine (FLT)–positron emission tomography (PET) is a novel imaging modality that provides detailed quantitative images of proliferating tissues, including bone marrow. We used FLT-PET imaging in cancer patients to produce an atlas of marrow distribution with potential clinical utility. Methods and Materials: The FLT-PET and fused CT scans of eligible patients with non-small cell lung cancer (no distant metastases, no prior cytotoxic exposure, no hematologic disorders) were reviewed. The proportions of skeletal FLT activity in 10 predefined bony regions were determined and compared according to age, sex, and recent smoking status. Results: Fifty-one patients were studied: 67% male; median age 68 (range, 31-87) years; 8% never smokers; 70% no smoking in the preceding 3 months. Significant differences in marrow distribution occurred between sex and age groups. No effect was detected from smoking in the preceding 3 months. Using the mean percentages of FLT uptake per body region, we created an atlas of the distribution of functional bone marrow in 4 subgroups defined by sex and age. Conclusions: This atlas has potential utility for estimating the distribution of active marrow in adult cancer patients to guide radiation therapy planning. However, because of interindividual variation it should be used with caution when radiation therapy risks ablating large proportions of active marrow; in such cases, individual FLT-PET scans may be required.

  8. Vascularized Bone Tissue Engineering: Approaches for Potential Improvement

    PubMed Central

    Nguyen, Lonnissa H.; Annabi, Nasim; Nikkhah, Mehdi; Bae, Hojae; Binan, Loïc; Park, Sangwon; Kang, Yunqing

    2012-01-01

    Significant advances have been made in bone tissue engineering (TE) in the past decade. However, classical bone TE strategies have been hampered mainly due to the lack of vascularization within the engineered bone constructs, resulting in poor implant survival and integration. In an effort toward clinical success of engineered constructs, new TE concepts have arisen to develop bone substitutes that potentially mimic native bone tissue structure and function. Large tissue replacements have failed in the past due to the slow penetration of the host vasculature, leading to necrosis at the central region of the engineered tissues. For this reason, multiple microscale strategies have been developed to induce and incorporate vascular networks within engineered bone constructs before implantation in order to achieve successful integration with the host tissue. Previous attempts to engineer vascularized bone tissue only focused on the effect of a single component among the three main components of TE (scaffold, cells, or signaling cues) and have only achieved limited success. However, with efforts to improve the engineered bone tissue substitutes, bone TE approaches have become more complex by combining multiple strategies simultaneously. The driving force behind combining various TE strategies is to produce bone replacements that more closely recapitulate human physiology. Here, we review and discuss the limitations of current bone TE approaches and possible strategies to improve vascularization in bone tissue substitutes. PMID:22765012

  9. Degradation pattern of porous CaCO3 and hydroxyapatite microspheres in vitro and in vivo for potential application in bone tissue engineering.

    PubMed

    Zhong, Qiwei; Li, Wenhua; Su, Xiuping; Li, Geng; Zhou, Ying; Kundu, Subhas C; Yao, Juming; Cai, Yurong

    2016-07-01

    Despite superior clinical handling, excellent biocompatibility, biodegradation property of calcium phosphate needs to be improved to coincide with the rate of new bone formation. In this study, spherical CaCO3 are fabricated in the presence of the silk sericin and then transformed into porous hydroxyapatite (HAP) microspheres via hydrothermal method. The degradation behavior of obtained CaCO3, HAP and their mixture is first investigated in vitro. The result demonstrates that the weight loss of HAP microspheres are almost 24.3% after immersing in pH 7.40 Tris-HCl buffer solution for 12 weeks, which is far slower than that of spherical CaCO3 (97.5%). The degradation speed of the mixtures depends on the proportion of CaCO3 and HAP. The mixture with higher content of CaCO3 possesses a quicker degradation speed. The obtained CaCO3 and HAP microspheres are injected into subcutaneous tissue of ICR mice with the assistance of sodium alginate. The result in vivo also shows an obvious difference of degradation speed between the obtained CaCO3 and HAP microspheres, implying it is feasible to modulate the degradation property of the mixture through changing the proportion of CaCO3 and HAP The good cytocompatibility of the two kinds of microspheres is proved and a mild inflammation response is observed only at early stage of implantation. The job offers a simple method to modify the degradation properties of biomaterial for potential use in bone tissue engineering. PMID:26998866

  10. Vitamin D and Bone Health; Potential Mechanisms

    PubMed Central

    Laird, Eamon; Ward, Mary; McSorley, Emeir; Strain, J.J.; Wallace, Julie

    2010-01-01

    Osteoporosis is associated with increased morbidity, mortality and significant economic and health costs. Vitamin D is a secosteriod hormone essential for calcium absorption and bone mineralization which is positively associated with bone mineral density [BMD]. It is well-established that prolonged and severe vitamin D deficiency leads to rickets in children and osteomalacia in adults. Sub-optimal vitamin D status has been reported in many populations but it is a particular concern in older people; thus there is clearly a need for effective strategies to optimise bone health. A number of recent studies have suggested that the role of vitamin D in preventing fractures may be via its mediating effects on muscle function (a defect in muscle function is one of the classical signs of rickets) and inflammation. Studies have demonstrated that vitamin D supplementation can improve muscle strength which in turn contributes to a decrease in incidence of falls, one of the largest contributors to fracture incidence. Osteoporosis is often considered to be an inflammatory condition and pro-inflammatory cytokines have been associated with increased bone metabolism. The immunoregulatory mechanisms of vitamin D may thus modulate the effect of these cytokines on bone health and subsequent fracture risk. Vitamin D, therefore, may influence fracture risk via a number of different mechanisms. PMID:22254049

  11. Terrestrial applications of bone and muscle research in microgravity

    NASA Astrophysics Data System (ADS)

    Booth, F. W.

    1994-08-01

    Major applications to people on Earth are possible from NASA-sponsored research on bone and muscle which is conducted either in microgravity or on Earth using models mimicking microgravity. In microgravity bone and muscle mass are lost. Humans experience a similar loss under certain conditions on Earth. Bone and muscle loss exist on Earth as humans age from adulthood to senescence, during limb immobilization for healing of orthopedic injuries, during wheelchair confinement because of certain diseases, and during chronic bed rest prescribed for curing of diseases. NASA-sponsored research is dedicated to learning both what cause bone and muscle loss as well as finding out how to prevent this loss. The health ramifications of these discoveries will have major impact. Objective 1.6 of Healthy People 2000, a report from the U.S. Department of Health and Human Services, states that the performance of physical activities that improve muscular strength, muscular endurance, and flexibility is particularly important to maintaining functional independence and social integration in older adults /1/. This objective further states that these types of physical activities are important because they may protect against disability, an event which costs the U.S. economy hugh sums of money. Thus NASA research related to bone and muscle loss has potential major impact on the quality of life in the U.S. Relative to its potential health benefits, NASA and Congressional support of bone and muscle research is funded is a very low level.

  12. Dynamic skeletal muscle stimulation and its potential in bone adaptation

    PubMed Central

    Qin, Y-X.; Lam, H.; Ferreri, S.; Rubin, C.

    2016-01-01

    To identify mechanotransductive signals for combating musculoskeletal deterioration, it is essential to determine the components and mechanisms critical to the anabolic processes of musculoskeletal tissues. It is hypothesized that the interaction between bone and muscle may depend on fluid exchange in these tissues by mechanical loading. It has been shown that intramedullary pressure (ImP) and low-level bone strain induced by muscle stimulation (MS) has the potential to mitigate bone loss induced by disuse osteopenia. Optimized MS signals, i.e., low-intensity and high frequency, may be critical in maintaining bone mass and mitigating muscle atrophy. The objectives for this review are to discuss the potential for MS to induce ImP and strains on bone, to regulate bone adaptation, and to identify optimized stimulation frequency in the loading regimen. The potential for MS to regulate blood and fluid flow will also be discussed. The results suggest that oscillatory MS regulates fluid dynamics with minimal mechanical strain in bone. The response was shown to be dependent on loading frequency, serving as a critical mediator in mitigating bone loss. A specific regimen of dynamic MS may be optimized in vivo to attenuate disuse osteopenia and serve as a biomechanical intervention in the clinical setting. PMID:20190376

  13. Metastatic potential of an aneurysmal bone cyst.

    PubMed

    van de Luijtgaarden, Addy C M; Veth, Rene P H; Slootweg, Piet J; Wijers-Koster, Pauline M; Schultze Kool, Leo J; Bovee, Judith V M G; van der Graaf, Winette T A

    2009-11-01

    Aneurysmal bone cysts (ABCs) are benign bone tumors consisting of blood-filled cavities lined by connective tissue septa. Recently, the hypothesis that ABCs are lesions reactive to local hemodynamics has been challenged after the discovery of specific recurrent chromosomal abnormalities. Multiple cases of malignant transformation of ABC into (osteo)sarcoma have been described, as well as a number of cases of telangiectatic osteosarcoma which had been misdiagnosed as ABC. We herewith document a case of a pelvic ABC metastatic to the lung, liver, and kidneys. Diagnosis was confirmed by the presence of a break in the USP6 gene, which is pathognomonic for ABC, in a pulmonary metastasis of our patient. Sarcomatous transformation as an explanation for this behavior was ruled out by demonstrating diploid DNA content in both the pulmonary lesion and the primary tumor. PMID:19838726

  14. Modeling fluorescence recovery after photobleaching in loaded bone: potential applications in measuring fluid and solute transport in the osteocytic lacunar-canalicular system.

    PubMed

    Zhou, Xiaozhou; Novotny, John E; Wang, Liyun

    2008-12-01

    Solute transport through the bone lacunar-canalicular system is essential for osteocyte viability and function, and it can be measured using fluorescence recovery after photobleaching (FRAP). The mathematical model developed here aims to analyze solute transport during FRAP in mechanically loaded bone. Combining both whole bone-level poroelasticity and cellular-level solute transport, we found that load-induced solute transport during FRAP is characterized by an exponential recovery rate, which is determined by the dimensionless Strouhal (St) number that characterizes the oscillation effects over the mean flows, and that significant transport occurs only for St values below a threshold, when the solute stroke displacement exceeds the distance between the source and sink (the canalicular length). This threshold mechanism explains the general flow behaviors such as increasing transport with increasing magnitude and decreasing frequency. Mechanical loading is predicted to enhance transport of all tracers relative to diffusion, with the greatest enhancement for medium-sized tracers and less enhancement for small and large tracers. This study provides guidelines for future FRAP experiments, based on which the model can be used to quantify bone permeability, solute-matrix interaction, and flow velocities. These studies should provide insights into bone adaptation and metabolism, and help to treat various bone diseases and conditions. PMID:18810639

  15. Osteogenic Potential of Multipotent Adult Progenitor Cells for Calvaria Bone Regeneration

    PubMed Central

    Lee, Dong Joon; Park, Yonsil; Hu, Wei-Shou; Ko, Ching-Chang

    2016-01-01

    Osteogenic cells derived from rat multipotent adult progenitor cells (rMAPCs) were investigated for their potential use in bone regeneration. rMAPCs are adult stem cells derived from bone marrow that have a high proliferation capacity and the differentiation potential to multiple lineages. They may also offer immunomodulatory properties favorable for applications for regenerative medicine. rMAPCs were cultivated as single cells or as 3D aggregates in osteogenic media for up to 38 days, and their differentiation to bone lineage was then assessed by immunostaining of osteocalcin and collagen type I and by mineralization assays. The capability of rMAPCs in facilitating bone regeneration was evaluated in vivo by the direct implantation of multipotent adult progenitor cell (MAPC) aggregates in rat calvarial defects. Bone regeneration was examined radiographically, histologically, and histomorphometrically. Results showed that rMAPCs successfully differentiated into osteogenic lineage by demonstrating mineralized extracellular matrix formation in vitro and induced new bone formation by the effect of rMAPC aggregates in vivo. These outcomes confirm that rMAPCs have a good osteogenic potential and provide insights into rMAPCs as a novel adult stem cell source for bone regeneration. PMID:27239552

  16. Singled-walled carbon nanotubes produced by induction thermal plasma: Cytotoxicity evaluation of the feedstock materials and the final product for a potential bone application

    NASA Astrophysics Data System (ADS)

    Alinejad, Yasaman

    One of the most challenging issues that the technologies related to nanomaterials face is the impact they have on human health and environment. It is therefore of great importance to investigate the toxicological impacts of these technologies prior to their widespread utilization in different fields of application. Therefore, in this study, the cytotoxicity of the materials present throughout the process of single-walled carbon nanotubes (SWCNTs) synthesis by induction thermal plasma (from the feedstock materials to the final product) was evaluated. First of all, the influence of the induction thermal plasma process on the physico-chemical and cytotoxic properties of feedstock materials (i.e. commercial Co, Ni, Y2O3, Mo catalysts and carbon black) was investigated. The strongest cytotoxicity was observed for commercial Co compared to other catalysts. Although the thermal plasma process affected the properties of all catalysts, only the cytotoxicity of Ni was increased. Comparing the properties and cytotoxicity of the plasma treated Ni particles with commercial Ni nanoparticles revealed that the particles with similar surface area had different cytotoxicities. Plus, the observed cytotoxicity of the catalysts was not mainly due to the release of ions. In order to evaluate the capacity of the RF induction thermal plasma process to produce high quality SWCNTs using non-toxic catalysts, the effects of the type and quantity of three catalyst mixtures (Ni-Y2O 3, Ni-Co-Y2O3, and Ni-Mo-Y2O3 ) on SWCNTs synthesis were examined. Thermodynamic calculations, in gas and particularly in liquid solution phases, were also performed. The results showed that catalyst type affected the quality of the SWCNT final product and similar quality SWCNTs was produced when the same amount of Co was replaced by Ni. Then, to investigate the cytotoxicity of the SWCNTs produced with the three catalyst mixtures, their effect was evaluated on the behavior of murine MC3T3-E1 preosteoblasts. Either

  17. Solid Free-form Fabrication Technology and Its Application to Bone Tissue Engineering

    PubMed Central

    Lee, Jin Woo; Kim, Jong Young; Cho, Dong-Woo

    2010-01-01

    The development of scaffolds for use in cell-based therapies to repair damaged bone tissue has become a critical component in the field of bone tissue engineering. However, design of scaffolds using conventional fabrication techniques has limited further advancement, due to a lack of the required precision and reproducibility. To overcome these constraints, bone tissue engineers have focused on solid free-form fabrication (SFF) techniques to generate porous, fully interconnected scaffolds for bone tissue engineering applications. This paper reviews the potential application of SFF fabrication technologies for bone tissue engineering with respect to scaffold fabrication. In the near future, bone scaffolds made using SFF apparatus should become effective therapies for bone defects. PMID:24855546

  18. [Bone morphogenetic proteins (BMP): clinical application for reconstruction of bone defects].

    PubMed

    Sierra-García, Gerardo Daniel; Castro-Ríos, Rocío; Gónzalez-Horta, Azucena; Lara-Arias, Jorge; Chávez-Montes, Abelardo

    2016-01-01

    Since the introduction of bone morphogenetic proteins, their use has become an invaluable ally for the treatment of bone defects. These proteins are potent growth factors, related to angiogenic and osteogenic activity. The osteoinductive capacity of recombinant bone morphogenetic protein (rhBMP) in the formation of bone and cartilage has been confirmed in in vitro studies and evaluated in clinical trials. To obtain a therapeutic effect, administration is systemic, by injection over the physiological dose. Among the disadvantages, ectopic bone formation or high morbidity in cases of spinal fusion is observed. In this review, the roles of bone morphogenetic proteins in bone repair and clinical applications are analyzed. These findings represent advances in the study of bone regeneration and application of growth factors for more predictable results. PMID:27335195

  19. A Therapeutic Potential for Marine Skeletal Proteins in Bone Regeneration

    PubMed Central

    Green, David W.; Padula, Matthew P.; Santos, Jerran; Chou, Joshua; Milthorpe, Bruce; Ben-Nissan, Besim

    2013-01-01

    A vital ingredient for engineering bone tissue, in the culture dish, is the use of recombinant matrix and growth proteins to help accelerate the growth of cultivated tissues into clinically acceptable quantities. The skeletal organic matrices of calcifying marine invertebrates are an untouched potential source of such growth inducing proteins. They have the advantage of being ready-made and retain the native state of the original protein. Striking evidence shows that skeleton building bone morphogenic protein-2/4 (BMP) and transforming growth factor beta (TGF-β) exist within various marine invertebrates such as, corals. Best practice mariculture and the latest innovations in long-term marine invertebrate cell cultivation can be implemented to ensure that these proteins are produced sustainably and supplied continuously. This also guarantees that coral reef habitats are not damaged during the collection of specimens. Potential proteins for bone repair, either extracted from the skeleton or derived from cultivated tissues, can be identified, evaluated and retrieved using chromatography, cell assays and proteomic methods. Due to the current evidence for bone matrix protein analogues in marine invertebrates, together with the methods established for their production and retrieval there is a genuine prospect that they can be used to regenerate living bone for potential clinical use. PMID:23574983

  20. The potential impact of bone tissue engineering in the clinic.

    PubMed

    Mishra, Ruchi; Bishop, Tyler; Valerio, Ian L; Fisher, John P; Dean, David

    2016-09-01

    Bone tissue engineering (BTE) intends to restore structural support for movement and mineral homeostasis, and assist in hematopoiesis and the protective functions of bone in traumatic, degenerative, cancer, or congenital malformation. While much effort has been put into BTE, very little of this research has been translated to the clinic. In this review, we discuss current regenerative medicine and restorative strategies that utilize tissue engineering approaches to address bone defects within a clinical setting. These approaches involve the primary components of tissue engineering: cells, growth factors and biomaterials discussed briefly in light of their clinical relevance. This review also presents upcoming advanced approaches for BTE applications and suggests a probable workpath for translation from the laboratory to the clinic. PMID:27549369

  1. Strontium borate glass: potential biomaterial for bone regeneration

    PubMed Central

    Pan, H. B.; Zhao, X. L.; Zhang, X.; Zhang, K. B.; Li, L. C.; Li, Z. Y.; Lam, W. M.; Lu, W. W.; Wang, D. P.; Huang, W. H.; Lin, K. L.; Chang, J.

    2010-01-01

    Boron plays important roles in many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the delivery of boron by the degradation of borate glass is of special interest in biomedical applications. However, the cytotoxicity of borate glass which arises with the rapid release of boron has to be carefully considered. In this study, it was found that the incorporation of strontium into borate glass can not only moderate the rapid release of boron, but also induce the adhesion of osteoblast-like cells, SaOS-2, thus significantly increasing the cyto-compatibility of borate glass. The formation of multilayers of apatite with porous structure indicates that complete degradation is optimistic, and the spread of SaOS-2 covered by apatite to form a sandwich structure may induce bone-like tissue formation at earlier stages. Therefore, such novel strontium-incorporated borosilicate may act as a new generation of biomaterial for bone regeneration, which not only renders boron as a nutritious element for bone health, but also delivers strontium to stimulate formation of new bones. PMID:20031984

  2. Application potential of bone marrow mesenchymal stem cell (BMSCs) based tissue-engineering for spinal cord defect repair in rat fetuses with spina bifida aperta.

    PubMed

    Li, Xiaoshuai; Yuan, Zhengwei; Wei, Xiaowei; Li, Hui; Zhao, Guifeng; Miao, Jiaoning; Wu, Di; Liu, Bo; Cao, Songying; An, Dong; Ma, Wei; Zhang, Henan; Wang, Weilin; Wang, Qiushi; Gu, Hui

    2016-04-01

    Spina bifida aperta are complex congenital malformations resulting from failure of fusion in the spinal neural tube during embryogenesis. Despite surgical repair of the defect, most patients who survive with spina bifida aperta have a multiple system handicap due to neuron deficiency of the defective spinal cord. Tissue engineering has emerged as a novel treatment for replacement of lost tissue. This study evaluated the prenatal surgical approach of transplanting a chitosan-gelatin scaffold seeded with bone marrow mesenchymal stem cells (BMSCs) in the healing the defective spinal cord of rat fetuses with retinoic acid induced spina bifida aperta. Scaffold characterisation revealed the porous structure, organic and amorphous content. This biomaterial promoted the adhesion, spreading and in vitro viability of the BMSCs. After transplantation of the scaffold combined with BMSCs, the defective region of spinal cord in rat fetuses with spina bifida aperta at E20 decreased obviously under stereomicroscopy, and the skin defect almost closed in many fetuses. The transplanted BMSCs in chitosan-gelatin scaffold survived, grew and expressed markers of neural stem cells and neurons in the defective spinal cord. In addition, the biomaterial presented high biocompatibility and slow biodegradation in vivo. In conclusion, prenatal transplantation of the scaffold combined with BMSCs could treat spinal cord defect in fetuses with spina bifida aperta by the regeneration of neurons and repairmen of defective region. PMID:26894267

  3. Effects of microstructure and water on the electrical potentials in bone induced by ultrasound irradiation

    SciTech Connect

    Tsuneda, H.; Matsukawa, S.; Takayanagi, S.; Matsukawa, M.; Mizuno, K.; Yanagitani, T.

    2015-02-16

    The healing mechanism of bone fractures by low intensity pulse ultrasound is yet to be fully understood. There have been many discussions regarding how the high frequency dynamic stress can stimulate numerous cell types through various pathways. As one possible initial process of this mechanism, we focus on the piezoelectricity of bone and demonstrate that bone can generate electrical potentials by ultrasound irradiation in the MHz range. We have fabricated ultrasonic bone transducers using bovine cortical bone as the piezoelectric device. The ultrasonically induced electrical potentials in the transducers change as a function of time during immersed ultrasonic pulse measurements and become stable when the bone is fully wet. In addition, the magnitude of the induced electrical potentials changes owing to the microstructure in the cortical bone. The potentials of transducers with haversian structure bone are higher than those of plexiform structure bone, which informs about the effects of bone microstructure on the piezoelectricity.

  4. Digital image processing of bone - Problems and potentials

    NASA Technical Reports Server (NTRS)

    Morey, E. R.; Wronski, T. J.

    1980-01-01

    The development of a digital image processing system for bone histomorphometry and fluorescent marker monitoring is discussed. The system in question is capable of making measurements of UV or light microscope features on a video screen with either video or computer-generated images, and comprises a microscope, low-light-level video camera, video digitizer and display terminal, color monitor, and PDP 11/34 computer. Capabilities demonstrated in the analysis of an undecalcified rat tibia include the measurement of perimeter and total bone area, and the generation of microscope images, false color images, digitized images and contoured images for further analysis. Software development will be based on an existing software library, specifically the mini-VICAR system developed at JPL. It is noted that the potentials of the system in terms of speed and reliability far exceed any problems associated with hardware and software development.

  5. Potential biomedical applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Babbush, C. A.; Vankampen, C. L.

    1976-01-01

    Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic pros-thesis fixtion, and dental implants.

  6. Potential biomedical applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Van Kampen, C. L.; Babbush, C. A.

    1976-01-01

    Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic prosthesis fixation, and dental implants.

  7. Space Nutrition: Effects on Bone and Potential Nutrition Countermeasures

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.

    2008-01-01

    Optimal nutrition will be critical for crew members who embark on space exploration missions. Nutritional assessment provides an opportunity to ensure that crewmembers begin their missions in optimal nutritional status, to document changes during a mission and , if necessary, to provide intervention to maintain that status throughout the mission, and to assesses changes after landing in order to facilitate the return to their normal status as soon as possible after landing. We report here the findings from our nutritional assessment of the US astronauts who participated in the first eight International Space Station (ISS) missions. Bone loss during space flight remains one of the most critical challenges to astronaut health on space exploration missions. An increase in bone resorption of ISS crew members after flight was indicated by several markers. Vitamin D status also remains a challenge for long-duration space travelers, who lack ultraviolet light exposure in the shielded craft. Many nutrients affect bone, including calcium, protein, fatty acids, sodium, and others. Data supporting their potential as countermeasures for space flight, as published in many papers, will be reviewed in this presentation. Defining nutrient requirements, and being able to provide and maintain those nutrients on exploration missions, will be critical for maintaining crew member health. Please note, this abstract is not required for the meeting. A presentation on the topics described above will be given. This abstract is for travel documentation only.

  8. Methods and application of bone densitometry in clinical diagnosis

    SciTech Connect

    Wahner, H.W.; Riggs, B.L.

    1986-01-01

    With the awareness of osteoporosis as a major health problem for an aging population, there is great interest in early recognition and treatment of abnormal bone loss. Effective prevention of bone loss has to occur prior to the occurrence of irreparable damage. Standard radiographic procedures are not sensitive enough for the task. Therefore, a number of alternative procedures to estimate bone loss have been developed over the years, ranging from efforts to quantitate information obtained from radiographic images to sophisticated procedures such as neutron activation analysis or procedures based on the Compton scatter phenomenon. Only two procedures, photon absorptiometry and computed tomography (CT), have emerged as applicable for routine clinical use. In photon absorptiometry the entire bone mineral (cortical and trabecular bone) of a specific skeletal site is measured. CT allows measuring of bone mineral of trabecular or cortical bone alone. Normally, bone mass reaches a maximum in the third decade and then continuously declines. This age-related bone loss is greater in women in whom an accelerated rate of loss occurs at the menopause. When bone density reaches a critical fracture threshold, skeletal fractures occur (spine, hip, and distal long bones). The age at which this critical fracture threshold is reached depends on the maximal bone mass achieved in early adulthood and the rate of loss with increasing age. With the exception of NaF, present-day therapeutic efforts only retard or prevent bone loss but do not significantly add bone mineral to the skeleton. Recognition of high-risk groups and early treatment are therefore required. 79 references.

  9. Application of rhenium-188 HEDP in bone metastases therapy.

    PubMed

    Scheffler, Justyna; Derejko, Mirosława; Bandurski, Tomasz; Romanowicz, Grzegorz

    2003-01-01

    Radionuclide bone metastases therapy is a major achievement of nuclear medicine. Development of less radiotoxic and more effective radiopharmaceuticals is therefore a challenge for radiopharmacists and industry. This paper reviews the application of rhenium-188 HEDP as a reactor- or generator-produced nuclide for bone metastases therapy. PMID:14600935

  10. Diffusion of Protease into Meat & Bone Meal for Solubility Improvement and Potential Inactivation of the BSE Prion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Government-imposed feed bans have created a need for new applications for meat & bone meal (MBM). Many potential new applications require MBM protein to be both soluble and free of infectious prions. Treatment with protease is generally effective in reducing insoluble, thermally-denatured proteins ...

  11. Diffusion of Protease into Meat & Bone Meal for Solubility Improvement and Potential Inactivation of the BSE Prion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Government-imposed feed bans have created a need for new applications for meat & bone meal (MBM). Many potential new applications require MBM protein to be both soluble and free of infectious prion. Treatment with protease is generally effective in reducing insoluble, thermally-denatured proteins t...

  12. Osteogenic differentiation of amniotic fluid mesenchymal stromal cells and their bone regeneration potential.

    PubMed

    Pipino, Caterina; Pandolfi, Assunta

    2015-05-26

    In orthopedics, tissue engineering approach using stem cells is a valid line of treatment for patients with bone defects. In this context, mesenchymal stromal cells of various origins have been extensively studied and continue to be a matter of debate. Although mesenchymal stromal cells from bone marrow are already clinically applied, recent evidence suggests that one may use mesenchymal stromal cells from extra-embryonic tissues, such as amniotic fluid, as an innovative and advantageous resource for bone regeneration. The use of cells from amniotic fluid does not raise ethical problems and provides a sufficient number of cells without invasive procedures. Furthermore, they do not develop into teratomas when transplanted, a consequence observed with pluripotent stem cells. In addition, their multipotent differentiation ability, low immunogenicity, and anti-inflammatory properties make them ideal candidates for bone regenerative medicine. We here present an overview of the features of amniotic fluid mesenchymal stromal cells and their potential in the osteogenic differentiation process. We have examined the papers actually available on this regard, with particular interest in the strategies applied to improve in vitro osteogenesis. Importantly, a detailed understanding of the behavior of amniotic fluid mesenchymal stromal cells and their osteogenic ability is desirable considering a feasible application in bone regenerative medicine. PMID:26029340

  13. Osteogenic differentiation of amniotic fluid mesenchymal stromal cells and their bone regeneration potential

    PubMed Central

    Pipino, Caterina; Pandolfi, Assunta

    2015-01-01

    In orthopedics, tissue engineering approach using stem cells is a valid line of treatment for patients with bone defects. In this context, mesenchymal stromal cells of various origins have been extensively studied and continue to be a matter of debate. Although mesenchymal stromal cells from bone marrow are already clinically applied, recent evidence suggests that one may use mesenchymal stromal cells from extra-embryonic tissues, such as amniotic fluid, as an innovative and advantageous resource for bone regeneration. The use of cells from amniotic fluid does not raise ethical problems and provides a sufficient number of cells without invasive procedures. Furthermore, they do not develop into teratomas when transplanted, a consequence observed with pluripotent stem cells. In addition, their multipotent differentiation ability, low immunogenicity, and anti-inflammatory properties make them ideal candidates for bone regenerative medicine. We here present an overview of the features of amniotic fluid mesenchymal stromal cells and their potential in the osteogenic differentiation process. We have examined the papers actually available on this regard, with particular interest in the strategies applied to improve in vitro osteogenesis. Importantly, a detailed understanding of the behavior of amniotic fluid mesenchymal stromal cells and their osteogenic ability is desirable considering a feasible application in bone regenerative medicine. PMID:26029340

  14. Microporous bacterial cellulose as a potential scaffold for bone regeneration.

    PubMed

    Zaborowska, Magdalena; Bodin, Aase; Bäckdahl, Henrik; Popp, Jenni; Goldstein, Aaron; Gatenholm, Paul

    2010-07-01

    Nanoporous cellulose biosynthesized by bacteria is an attractive biomaterial scaffold for tissue engineering due to its biocompatibility and good mechanical properties. However, for bone applications a microscopic pore structure is needed to facilitate osteoblast ingrowth and formation of a mineralized tissue. Therefore, in this study microporous bacterial cellulose (BC) scaffolds were prepared by incorporating 300-500 microm paraffin wax microspheres into the fermentation process. The paraffin wax microspheres were subsequently removed, and scanning electron microscopy confirmed a microporous surface of the scaffolds while Fourier transform infrared spectroscopy verified the elimination of paraffin and tensile measurements showed a Young's modulus of approximately 1.6 MPa. Microporous BC and nanoporous (control) BC scaffolds were seeded with MC3T3-E1 osteoprogenitor cells, and examined by confocal microscopy and histology for cell distribution and mineral deposition. Cells clustered within the pores of microporous BC, and formed denser mineral deposits than cells grown on control BC surfaces. This work shows that microporous BC is a promising biomaterial for bone tissue engineering applications. PMID:20060935

  15. Preparation and characterization of an iron oxide-hydroxyapatite nanocomposite for potential bone cancer therapy

    PubMed Central

    Sneha, Murugesan; Sundaram, Nachiappan Meenakshi

    2015-01-01

    Recently, multifunctional magnetic nanostructures have been found to have potential applications in biomedical and tissue engineering. Iron oxide nanoparticles are biocompatible and have distinctive magnetic properties that allow their use in vivo for drug delivery and hyperthermia, and as T2 contrast agents for magnetic resonance imaging. Hydroxyapatite is used frequently due to its well-known biocompatibility, bioactivity, and lack of toxicity, so a combination of iron oxide and hydroxyapatite materials could be useful because hydroxyapatite has better bone-bonding ability. In this study, we prepared nanocomposites of iron oxide and hydroxyapatite and analyzed their physicochemical properties. The results suggest that these composites have superparamagnetic as well as biocompatible properties. This type of material architecture would be well suited for bone cancer therapy and other biomedical applications. PMID:26491311

  16. In vitro osteoinductive potential of porous monetite for bone tissue engineering

    PubMed Central

    Idowu, Bernadine; Cama, Giuseppe; Deb, Sanjukta

    2014-01-01

    Tissue engineering–based bone grafts are emerging as a viable alternative treatment modality to repair and regenerate tissues damaged as a result of disease or injury. The choice of the biomaterial component is a critical determinant of the success of the graft or scaffold; essentially, it must induce and allow native tissue integration, and most importantly mimic the hierarchical structure of the native bone. Calcium phosphate bioceramics are widely used in orthopaedics and dentistry applications due to their similarity to bone mineral and their ability to induce a favourable biological response. One such material is monetite, which is biocompatible, osteoconductive and has the ability to be resorbed under physiological conditions. The osteoinductive properties of monetite in vivo are known; however, little is known of the direct effect on osteoinduction of human mesenchymal stem cells in vitro. In this study, we evaluated the potential of monetite to induce and sustain human mesenchymal stem cells towards osteogenic differentiation. Human mesenchymal stem cells were seeded on the monetite scaffold in the absence of differentiating factors for up to 28 days. The gene expression profile of bone-specific markers in cells on monetite scaffold was compared to the control material hydroxyapatite. At day 14, we observed a marked increase in alkaline phosphatase, osteocalcin and osteonectin expressions. This study provides evidence of a suitable material that has potential properties to be used as a tissue engineering scaffold. PMID:24904727

  17. Novel applications of statins for bone regeneration

    PubMed Central

    Shah, Sarita R.; Werlang, Caroline A.; Kasper, F. Kurtis; Mikos, Antonios G.

    2015-01-01

    The use of statins for bone regeneration is a promising and growing area of research. Statins, originally developed to treat high cholesterol, are inhibitors of the enzyme 3-hydroxy-3-methylglutaryl, the rate-limiting enzyme of the mevalonate pathway. Because the mevalonate pathway is responsible for the synthesis of a wide variety of important biochemical molecules, including cholesterol and other isoprenoids, the effects of statins are pleiotropic. In particular, statins can greatly affect the process of bone turnover and regeneration via effects on important cell types, including mesenchymal stem cells, osteoblasts, endothelial cells, and osteoclasts. Statins have also been shown to have anti-inflammatory and antimicrobial properties that may be useful since infection can derail normal bone healing. This review will explore the pleiotropic effects of statins, discuss the current use of statins for bone regeneration, particularly with regard to biomaterials-based controlled delivery, and offer perspectives on the challenges and future directions of this emerging area of bone tissue engineering. PMID:26543666

  18. Development of electrospun bone-mimetic matrices for bone regenerative applications

    NASA Astrophysics Data System (ADS)

    Phipps, Matthew Christopher

    Although bone has a dramatic capacity for regeneration, certain injuries and procedures present defects that are unable to heal properly, requiring surgical intervention to induce and support osteoregeneration. Our research group has hypothesized that the development of a biodegradable material that mimics the natural composition and architecture of bone extracellular matrix has the potential to provide therapeutic benefit to these patients. Utilizing a process known as electrospinning, our lab has developed a bone-mimetic matrix (BMM) consisting of composite nanofibers of the mechanically sta-ble polymer polycaprolactone (PCL), and the natural bone matrix molecules type-I colla-gen and hydroxyapatite nanocrystals (HA). We herein show that BMMs supported great-er adhesion, proliferation, and integrin activation of mesenchymal stem cells (MSCs), the multipotent bone-progenitor cells within bone marrow and the periosteum, in comparison to electrospun PCL alone. These cellular responses, which are essential early steps in the process of bone regeneration, highlight the benefits of presenting cells with natural bone molecules. Subsequently, evaluation of new bone formation in a rat cortical tibia defect showed that BMMs are highly osteoconductive. However, these studies also revealed the inability of endogenous cells to migrate within electrospun matrices due to the inherently small pore sizes. To address this limitation, which will negatively impact the rate of scaf-fold-to-bone turnover and inhibit vascularization, sacrificial fibers were added to the ma-trix. The removal of these fibers after fabrication resulted in BMMs with larger pores, leading to increased infiltration of MSCs and endogenous bone cells. Lastly, we evaluat-ed the potential of our matrices to stimulate the recruitment of MSCs, a vital step in bone healing, through the sustained delivery of platelet derived growth factor-BB (PDGF-BB). BMMs were found to adsorb and subsequently release greater

  19. Freeze-cast hydroxyapatite scaffolds for bone tissue engineering applications.

    PubMed

    Fu, Qiang; Rahaman, Mohamed N; Dogan, Fatih; Bal, B Sonny

    2008-06-01

    Freeze casting of aqueous suspensions was investigated as a method for preparing porous hydroxyapatite (HA) scaffolds for eventual application to bone tissue engineering. Suspensions of HA particles (10-20 volume percent) were frozen unidirectionally in a cylindrical mold placed on a cold steel substrate (-20 degrees C). After sublimation of the ice, sintering for 3 h at 1350 degrees C produced constructs with dense HA lamellae, with porosity of approximately 50%, and inter-lamellar pore widths of 5-30 microm. These constructs had compressive strengths of 12 +/- 1 MPa and 5 +/- 1 MPa in the directions parallel and perpendicular to the freezing direction, respectively. Manipulation of the microstructure was achieved by modifying the solvent composition of the suspension used for freeze casting. The use of water-glycerol mixtures (20 wt% glycerol) resulted in the production of constructs with finer pores (1-10 microm) and a larger number of dendritic growth connecting the HA lamellae, and higher strength. On the other hand, the use of water-dioxane mixtures (60 wt% dioxane) resulted in a cellular-type microstructure with larger pores (90-110 microm). The mechanical response showed high strain tolerance (5-10% at the maximum stress), high strain for failure (>20%) and sensitivity to the loading rate. The favorable mechanical behavior of the porous constructs, coupled with the ability to modify their microstructure, indicates the potential of the present freeze casting route for the production of porous scaffolds for bone tissue engineering. PMID:18458369

  20. Cobalt doped proangiogenic hydroxyapatite for bone tissue engineering application.

    PubMed

    Kulanthaivel, Senthilguru; Roy, Bibhas; Agarwal, Tarun; Giri, Supratim; Pramanik, Krishna; Pal, Kunal; Ray, Sirsendu S; Maiti, Tapas K; Banerjee, Indranil

    2016-01-01

    The present study delineates the synthesis and characterization of cobalt doped proangiogenic-osteogenic hydroxyapatite. Hydroxyapatite samples, doped with varying concentrations of bivalent cobalt (Co(2+)) were prepared by the ammoniacal precipitation method and the extent of doping was measured by ICP-OES. The crystalline structure of the doped hydroxyapatite samples was confirmed by XRD and FTIR studies. Analysis pertaining to the effect of doped hydroxyapatite on cell cycle progression and proliferation of MG-63 cells revealed that the doping of cobalt supported the cell viability and proliferation up to a threshold limit. Furthermore, such level of doping also induced differentiation of the bone cells, which was evident from the higher expression of differentiation markers (Runx2 and Osterix) and better nodule formation (SEM study). Western blot analysis in conjugation with ELISA study confirmed that the doped HAp samples significantly increased the expression of HIF-1α and VEGF in MG-63 cells. The analysis described here confirms the proangiogenic-osteogenic properties of the cobalt doped hydroxyapatite and indicates its potential application in bone tissue engineering. PMID:26478356

  1. Synthesis and Characterization of Protein-Conjugated Silver Nanoparticles/Silver Salt Loaded Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Film for Prevention of Bacterial Infections and Potential Use in Bone Tissue Engineering Applications

    NASA Astrophysics Data System (ADS)

    Bakare, Rotimi Ayotunde

    concentration (0.19and 0.31 microg) compared to commercially available gentamicin and sulfamethoxazole/trimethoprim which showed sometimes selective antimicrobial activity and antimicrobial activity at high concentration (10 microg and 23.75/1.25 microg/disc). Additionally, a clear zone of inhibition around AgCl/PHBV composite film was noticed on a modified Kirby-Bauer disk diffusion assay. Optical density results and colony forming unit measurements showed that AgCl/PHBV composite film exhibit broad bactericidal activity. Next, we evaluated the cytotoxicity of Ag/BSA nanoparticles loaded collagen immobilized PHBV films and AgCl/PHBV composite films towards MC3T3-E1 cells at the same concentration both films showed broad antimicrobial activity. By using MTT assay, we established that Ag/BSA nanoparticles loaded collagen immobilized PHBV film showed minimal, if any, cytotoxic effect towards MC3T3-E1 cells while AgCl/PHBV composite film showed significant cytotoxic effect compared to tissue culture polystyrene. Our research findings provide several formulations for preparation of scaffold, if properly tuned; it can be used as a potential biocompatible and biodegradable scaffold for the prevention of bacterial infections and promotion of cell attachment and proliferation in bone tissue engineering applications.

  2. Bone metastases in lung cancer. Potential novel approaches to therapy.

    PubMed

    Vicent, Silvestre; Perurena, Naiara; Govindan, Ramaswamy; Lecanda, Fernando

    2015-10-01

    The skeleton is a common site of metastases in lung cancer, an event associated with significant morbidities and poor outcomes. Current antiresorptive therapies provide limited benefit, and novel strategies of prevention and treatment are urgently needed. This review summarizes the latest advances and new perspectives on emerging experimental and clinical approaches to block this deleterious process. Progress propelled by preclinical models has led to a deeper understanding on the complex interplay of tumor cells in the osseous milieu, unveiling potential new targets for drug development. Improvements in early diagnosis through the use of sophisticated imaging techniques with bone serum biomarkers are also discussed in the context of identifying patients at risk and monitoring disease progression during the course of treatment. PMID:26131844

  3. 99Tcm-LL1: a potential new bone marrow imaging agent.

    PubMed

    Juweid, M; Dunn, R M; Sharkey, R M; Rubin, A D; Hansen, H J; Goldenberg, D M

    1997-02-01

    LL1, a monoclonal antibody (MAb) to HLA Class-II-like antigen (li determinant) on the surface of B-lymphocytes, monocytes and histiocytes, was evaluated as an agent for bone marrow imaging. Six patients with diverse diseases (non-Hodgkin's lymphoma, n = 2; multiple myeloma, n = 1; polycythaemia vera, n = 1; lung cancer, n = 1; breast cancer, n = 1) were given low protein doses (< 1 mg) of 99Tcm (30 mCi) labelled Fab' of LL1. 99Tcm-sulphur colloid (SC) imaging was performed in three patients for comparison. Both planar and single photon emission tomographic images were acquired using Sopha gamma cameras. As early as 2 h post-MAb injection, excellent bone marrow images were achieved in all patients, demonstrating both normal or hyperproliferative marrow, as well as 'cold' bone marrow abnormalities such as radiation defects or cancer metastases. Similar to SC, relatively high uptake of LL1 was found in the liver and spleen. However, the bone marrow-to-liver and -spleen uptake ratios were approximately 19-fold higher (0.75 vs 0.04) and 6-fold higher (1.23 vs 0.22), respectively, with LL1 than with SC. The higher bone marrow uptake allowed clearly superior visualization of the thoracic spine when compared to SC. The mean T1/2 of blood and whole-body clearance were 0.4 and 66 h, respectively. The highest radiation absorbed doses (in cGy mCi-1) were observed in the spleen (0.47 +/- 0.24), kidneys (0.25 +/- 0.09) and liver (0.14 +/- 0.04). The bone marrow dose was only 0.05 +/- 0.02 cGy mCi-1. These results indicate that bone marrow imaging with 99Tcm-LL1 is feasible, and that LL1 may be a suitable alternative to SC because of better visualization of the lower thoracic spine. Potential applications include the improved detection of bone marrow metastases of solid tumours and the assessment of haematological disorders. PMID:9076770

  4. The use of total human bone marrow fraction in a direct three-dimensional expansion approach for bone tissue engineering applications: focus on angiogenesis and osteogenesis.

    PubMed

    Guerrero, Julien; Oliveira, Hugo; Catros, Sylvain; Siadous, Robin; Derkaoui, Sidi-Mohammed; Bareille, Reine; Letourneur, Didier; Amédée, Joëlle

    2015-03-01

    Current approaches in bone tissue engineering have shown limited success, mostly owing to insufficient vascularization of the construct. A common approach consists of co-culture of endothelial cells and osteoblastic cells. This strategy uses cells from different sources and differentiation states, thus increasing the complexity upstream of a clinical application. The source of reparative cells is paramount for the success of bone tissue engineering applications. In this context, stem cells obtained from human bone marrow hold much promise. Here, we analyzed the potential of human whole bone marrow cells directly expanded in a three-dimensional (3D) polymer matrix and focused on the further characterization of this heterogeneous population and on their ability to promote angiogenesis and osteogenesis, both in vitro and in vivo, in a subcutaneous model. Cellular aggregates were formed within 24 h and over the 12-day culture period expressed endothelial and bone-specific markers and a specific junctional protein. Ectopic implantation of the tissue-engineered constructs revealed osteoid tissue and vessel formation both at the periphery and within the implant. This work sheds light on the potential clinical use of human whole bone marrow for bone regeneration strategies, focusing on a simplified approach to develop a direct 3D culture without two-dimensional isolation or expansion. PMID:25333855

  5. The Use of Total Human Bone Marrow Fraction in a Direct Three-Dimensional Expansion Approach for Bone Tissue Engineering Applications: Focus on Angiogenesis and Osteogenesis

    PubMed Central

    Oliveira, Hugo; Catros, Sylvain; Siadous, Robin; Derkaoui, Sidi-Mohammed; Bareille, Reine; Letourneur, Didier; Amédée, Joëlle

    2015-01-01

    Current approaches in bone tissue engineering have shown limited success, mostly owing to insufficient vascularization of the construct. A common approach consists of co-culture of endothelial cells and osteoblastic cells. This strategy uses cells from different sources and differentiation states, thus increasing the complexity upstream of a clinical application. The source of reparative cells is paramount for the success of bone tissue engineering applications. In this context, stem cells obtained from human bone marrow hold much promise. Here, we analyzed the potential of human whole bone marrow cells directly expanded in a three-dimensional (3D) polymer matrix and focused on the further characterization of this heterogeneous population and on their ability to promote angiogenesis and osteogenesis, both in vitro and in vivo, in a subcutaneous model. Cellular aggregates were formed within 24 h and over the 12-day culture period expressed endothelial and bone-specific markers and a specific junctional protein. Ectopic implantation of the tissue-engineered constructs revealed osteoid tissue and vessel formation both at the periphery and within the implant. This work sheds light on the potential clinical use of human whole bone marrow for bone regeneration strategies, focusing on a simplified approach to develop a direct 3D culture without two-dimensional isolation or expansion. PMID:25333855

  6. Polycaprolactone fibres as a potential delivery system for collagen to support bone regeneration.

    PubMed

    McNeil, Sarah E; Griffiths, Helen R; Perrie, Yvonne

    2011-07-01

    Poly(ε-caprolactone) (PCL) is biocompatible, non-immunogenic and non-toxic, and slowly degrades, allowing sufficient time for tissue regeneration. PCL has the potential for application in bone and cartilage repair as it may provide the essential structure required for bone regeneration, however, an ideal scaffold system is still undeveloped. PCL fibres were prepared using the gravity spinning technique, in which collagen was either incorporated into or coated onto the 'as-spun' fibres, in order to develop novel biodegradable polymer fibres which will effectively deliver collagen and support the attachment and proliferation of human osteoblast (HOB) cells for bone regeneration. The physical and mechanical characteristics and cell fibre interactions were analysed. The PCL fibres were found to be highly flexible and inclusion of collagen did not alter the mechanical properties of PCL fibres. Overall, HOB cells were shown to effectively adhere and proliferate on all fibre platforms tested, although proliferation rates were enhanced by surface coating PCL fibres with collagen compared to PCL fibres incorporating collagen and PCL-only fibres. These findings highlight the potential of using gravity spun PCL fibres as a delivery platform for extracellular matrix proteins, such as collagen, in order to enhance cell adherence and proliferation for tissue repair. PMID:21235468

  7. Nanobiocatalysis and Its Potential Applications

    SciTech Connect

    Kim, Jungbae; Grate, Jay W.; Wang, Ping

    2008-11-01

    Nanobiocatalysis with enzymes incorporated into nanostructured materials have emerged as a rapidly growing area. Structures including nanoporous media, nanofibers, carbon nanotubes, and nanoparticles have been found to be efficient in manipulating the nanoscale environment of the enzyme and thus promising exciting advances in many areas of enzyme technology. This review will describe these recent developments in nanobiocatalysis and their potential applications in various fields such as trypsin digestion in proteomic analysis, antifouling, biofuel cells, and biosensors.

  8. Clinical potential of RANKL inhibition for the management of postmenopausal osteoporosis and other metabolic bone diseases.

    PubMed

    Delmas, Pierre D

    2008-01-01

    Osteoporosis affects millions of people worldwide, causing decreases in bone strength and a marked increase in fracture risk. Current therapies increase bone mineral density and reduce the risk of fractures, but dosing requirements are often considered inconvenient, and patient compliance with therapy is poor. This review will discuss recent discoveries in bone biology, which have demonstrated that the interaction of osteoprotegerin (OPG), receptor activator of nuclear factor--kappa B (RANK), and RANK ligand (RANKL) is critical for the regulation of bone remodeling. Collectively, these preclinical studies have shown that endogenous RANKL inhibition by OPG underlies the normal mechanism for maintaining the correct balance between bone resorption and bone formation. Multiple clinical trials are in progress to investigate the therapeutic potential of RANKL inhibition by denosumab, a fully human monoclonal anti-RANKL antibody, in the treatment of postmenopausal osteoporosis and other bone loss diseases. The results of these human trials will also be discussed. PMID:18375161

  9. The potential role of free chitosan in bone trauma and bone cancer management.

    PubMed

    Tan, Mei L; Shao, Peng; Friedhuber, Anna M; van Moorst, Mallory; Elahy, Mina; Indumathy, Sivanjah; Dunstan, Dave E; Wei, Yongzhong; Dass, Crispin R

    2014-09-01

    Bone defects caused by fractures or cancer-mediated destruction are debilitating. Chitosan is commonly used in scaffold matrices for bone healing, but rarely as a free drug. We demonstrate that free chitosan promotes osteoblast proliferation and osteogenesis in mesenchymal stem cells, increases osteopontin and collagen I expression, and reduces osteoclastogenesis. Chitosan inhibits invasion of endothelial cells, downregulating uPA/R, MT1-MMP, cdc42 and Rac1. Better healing of bone fractures with greater trabecular bone formation was observed in mice treated with chitosan. Chitosan induces apoptosis in osteotropic prostate and breast cancer cells via caspase-2 and -3 activation, and reduces their establishment in bone. Chitosan is pro-apoptotic in osteosarcoma cells, but not their normal counterpart, osteoblasts, or chondrosarcoma cells. Systemic delivery of chitosan does not perturb angiogenesis, bone volume or instinctive behaviour in pregnant mice, but decreases foetal length and changes pancreatic secretory acini. With certain controls in place, chitosan could be useful for bone trauma management. PMID:24947230

  10. Potentiation of osteoclast bone-resorption activity by inhibition of nitric oxide synthase.

    PubMed Central

    Kasten, T P; Collin-Osdoby, P; Patel, N; Osdoby, P; Krukowski, M; Misko, T P; Settle, S L; Currie, M G; Nickols, G A

    1994-01-01

    We have examined the effects of modulating nitric oxide (NO) levels on osteoclast-mediated bone resorption in vitro and the effects of nitric oxide synthase (NOS) inhibitors on bone mineral density in vivo. Diaphorase-based histochemical staining for NOS activity of bone sections or highly enriched osteoclast cultures suggested that osteoclasts exhibit substantial NOS activity that may account for basal NO production. Chicken osteoclasts were cultured for 36 hr on bovine bone slices in the presence or absence of the NO-generating agent sodium nitroprusside or the NOS inhibitors N-nitro-L-arginine methyl ester and aminoguanidine. Nitroprusside markedly decreased the number of bone pits and the average pit area in comparison with control cultures. On the other hand, NOS inhibition by N-nitro-L-arginine methyl ester or aminoguanidine dramatically increased the number of bone pits and the average resorption area per pit. In a model of osteoporosis, aminoguanidine potentiated the loss of bone mineral density in ovariectomized rats. Aminoguanidine also caused a loss of bone mineral density in the sham-operated rats. Inhibition of NOS activity in vitro and in vivo resulted in an apparent potentiation of osteoclast activity. These findings suggest that endogenous NO production in osteoclast cultures may regulate resorption activity. The modulation of NOS and NO levels by cells within the bone microenvironment may be a sensitive mechanism for local control of osteoclast bone resorption. Images PMID:7513424

  11. Design, synthesis, and initial evaluation of D-glyceraldehyde crosslinked gelatin-hydroxyapatite as a potential bone graft substitute material

    NASA Astrophysics Data System (ADS)

    Florschutz, Anthony Vatroslav

    Utilization of bone grafts for the treatment of skeletal pathology is a common practice in orthopaedic, craniomaxillofacial, dental, and plastic surgery. Autogenous bone graft is the established archetype but has disadvantages including donor site morbidity, limited supply, and prolonging operative time. In order to avoid these and other issues, bone graft substitute materials are becoming increasingly prevalent among surgeons for reconstructing skeletal defects and arthrodesis applications. Bone graft substitutes are biomaterials, biologics, and guided tissue/bone regenerative devices that can be used alone or in combinations as supplements or alternatives to autogenous bone graft. There is a growing interest and trend to specialize graft substitutes for specific indications and although there is good rationale for this indication-specific approach, the development and utility of a more universal bone graft substitute may provide a better answer for patients and surgeons. The aim of the present research focuses on the design, synthesis, and initial evaluation of D-glyceraldehyde crosslinked gelatin-hydroxyapatite composites for potential use as a bone graft substitutes. After initial establishment of rational material design, gelatinhydroxyapatite scaffolds were fabricated with different gelatin:hydroxyapatite ratios and crosslinking concentrations. The synthesized scaffolds were subsequently evaluated on the basis of their swelling behavior, porosity, density, percent composition, mechanical properties, and morphology and further assessed with respect to cell-biomaterial interaction and biomineralization in vitro. Although none of the materials achieved mechanical properties suitable for structural graft applications, a reproducible material design and synthesis was achieved with properties recognized to facilitate bone formation. Select scaffold formulations as well as a subset of scaffolds loaded with recombinant human bone morphogenetic protein-2 were

  12. Potential applications of bacteriorhodopsin mutants

    PubMed Central

    Saeedi, P.; Moosaabadi, J. Mohammadian; Sebtahmadi, S. Sina; Mehrabadi, J. Fallah; Behmanesh, M.; Mekhilef, S.

    2012-01-01

    Bacteriorhodopsin (BR), a model system in biotechnology, is a G-protein dependent trans membrane protein which serves as a light driven proton pump in the cell membrane of Halobacterium salinarum. Due to the linkage of retinal to the protein, it seems colored and has numbers of versatile properties. As in vitro culture of the Halobacteria is very difficult, and isolation is time consuming and usually inefficient, production of genetically modified constructs of the protein is essential. There are three important characteristics based on protein catalytic cycle and molecular functions of photo-electric, photochromic and proton transporting, which makes this protein as a strategic molecule with potential applications in biotechnology. Such applications include protein films, used in artificial retinal implants, light modulators, three-dimensional optical memories, color photochromic sensors, photochromic and electrochromic papers and ink, biological camouflage and photo detectors for biodefense and non-defense purposes. PMID:22895057

  13. Application of AMOR in Craniofacial Rabbit Bone Bioengineering

    PubMed Central

    Nguyen, Anthony; Chee, Young Deok; Kook, Joong-Ki; Zadeh, Homayoun H.

    2015-01-01

    Endogenous molecular and cellular mediators modulate tissue repair and regeneration. We have recently described antibody mediated osseous regeneration (AMOR) as a novel strategy for bioengineering bone in rat calvarial defect. This entails application of anti-BMP-2 antibodies capable of in vivo capturing of endogenous osteogenic BMPs (BMP-2, BMP-4, and BMP-7). The present study sought to investigate the feasibility of AMOR in other animal models. To that end, we examined the efficacy of a panel of anti-BMP-2 monoclonal antibodies (mAbs) and a polyclonal Ab immobilized on absorbable collagen sponge (ACS) to mediate bone regeneration within rabbit calvarial critical size defects. After 6 weeks, de novo bone formation was demonstrated by micro-CT imaging, histology, and histomorphometric analysis. Only certain anti-BMP-2 mAb clones mediated significant in vivo bone regeneration, suggesting that the epitopes with which anti-BMP-2 mAbs react are critical to AMOR. Increased localization of BMP-2 protein and expression of osteocalcin were observed within defects, suggesting accumulation of endogenous BMP-2 and/or increased de novo expression of BMP-2 protein within sites undergoing bone repair by AMOR. Considering the ultimate objective of translation of this therapeutic strategy in humans, preclinical studies will be necessary to demonstrate the feasibility of AMOR in progressively larger animal models. PMID:25705677

  14. Prodigiosin and its potential applications.

    PubMed

    Darshan, N; Manonmani, H K

    2015-09-01

    Since a decade, there has been a strong consumer demand for more natural products. This has augmented inclination towards substitution of synthetic colorants with natural pigments. Natural pigments not only have the capacity to increase the marketability of products, they also demonstrate valuable biological activities as antioxidants and anticancer agents. There is a long history of exploitation of natural products produced by bacteria as sources of pharmaceutically important, bioactive compounds. Among natural pigments, pigments from microbial sources are potentially suitable alternatives to synthetic pigments. The red pigment prodigiosin (PG) has unusual properties, which have long been documented. The red-pigmented prodiginines are bioactive secondary metabolites produced by both Gram-negative and Gram-positive bacteria. Prodigiosins are characterized by a common pyrrolyl pyrromethene skeleton, and the biological role of these pigments in the producer organisms remains unclear. Bacterial prodigiosins and their synthetic derivatives are effective proapoptotic agents against various cancer cell lines, with multiple cellular targets including multi-drug resistant cells with little or no toxicity towards normal cell lines. However, research into the biology of pigment production will stimulate interest in the bioengineering of strains to synthesize useful prodiginine derivatives. This review article highlights the characteristics and potential applications of prodigiosin pigment from Serratia as prodigiosins are real potential therapeutic drugs. PMID:26344956

  15. Beyond osteogenesis: an in vitro comparison of the potentials of six bone morphogenetic proteins.

    PubMed

    Rivera, Jessica C; Strohbach, Cassandra A; Wenke, Joseph C; Rathbone, Christopher R

    2013-01-01

    Bone morphogenetic proteins (BMPs) other than the clinically available BMP-2 and BMP-7 may be useful for improving fracture healing through both increasing osteogenesis and creating a favorable healing environment by altering cytokine release by endogenous cells. Given the spectrum of potential applications for BMPs, the objective of this study was to evaluate various BMPs under a variety of conditions to provide further insight into their therapeutic capabilities. The alkaline phosphatase (ALP) activity of both C2C12 and human adipose-derived stem cells (hASCs) was measured after exposure of increasing doses of recombinant human BMP-2, -4, -5, -6, -7, or -9 for 3 and 7 days. BMPs-2, -4, -5, -6, -7, and -9 were compared in terms of their ability to affect the release of stromal derived factor-1 (SDF-1), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (b-FGF) from human bone marrow stromal cells (hBMSCs). Gene expression of ALP, osteocalcin, SDF-1, VEGF, and b-FGF following shRNA-mediated knockdown of BMP-2 and BMP-6 in hBMSCs or human osteoblasts under osteogenic differentiation conditions was also evaluated. Collectively, BMPs-6 and -9 produced the greatest osteogenic differentiation of C2C12 and hASCs as determined by ALP. The hBMSC secretion of SDF-1 was most affected by BMP-5, VEGF by BMP-4, and b-FGF by BMP-2. The knockdown of BMP-2 in BMSCs had no effect on any of the genes measured whereas BMP-6 knockdown in hBMSCs caused a significant increase in VEGF gene expression. BMP-2 and BMP-6 knockdown in human osteoblasts caused significant increases in VEGF gene expression and trends toward decreases in osteocalcin expression. These findings support efforts to study other BMPs as potential bone graft supplements, and to consider combined BMP delivery for promotion of multiple aspects of fracture healing. PMID:24101902

  16. A new biphasic osteoinductive calcium composite material with a negative Zeta potential for bone augmentation

    PubMed Central

    Smeets, Ralf; Kolk, Andreas; Gerressen, Marcus; Driemel, Oliver; Maciejewski, Oliver; Hermanns-Sachweh, Benita; Riediger, Dieter; Stein, Jamal M

    2009-01-01

    The aim of the present study was to analyze the osteogenic potential of a biphasic calcium composite material (BCC) with a negative surface charge for maxillary sinus floor augmentation. In a 61 year old patient, the BCC material was used in a bilateral sinus floor augmentation procedure. Six months postoperative, a bone sample was taken from the augmented regions before two titanium implants were inserted at each side. We analyzed bone neoformation by histology, bone density by computed tomography, and measured the activity of voltage-activated calcium currents of osteoblasts and surface charge effects. Control orthopantomograms were carried out five months after implant insertion. The BCC was biocompatible and replaced by new mineralized bone after being resorbed completely. The material demonstrated a negative surface charge (negative Zeta potential) which was found to be favorable for bone regeneration and osseointegration of dental implants. PMID:19523239

  17. A short latency vestibular evoked potential (VsEP) produced by bone-conducted acoustic stimulation

    NASA Astrophysics Data System (ADS)

    McAngus Todd, Neil P.; Rosengren, Sally M.; Colebatch, James G.

    2003-12-01

    In this paper data are presented from an experiment which provides evidence for the existence of a short latency, acoustically evoked potential of probable vestibular origin. The experiment was conducted in two phases using bone-conducted acoustic stimulation. In the first phase subjects were stimulated with 6-ms, 500-Hz tone bursts in order to obtain the threshold VT for vestibular evoked myogenic potentials (VEMP). It was confirmed that the difference between bone-conducted auditory and acoustic vestibular thresholds was slightly over 30 dB. The estimated threshold was then used as a reference value in the second part of the experiment to stimulate subjects over a range of intensities from -6 to +18 dB (re:VT). Averaged EEG recordings were made with eight Ag/AgCl electrodes placed on the scalp at Fpz, F3, F4, F7, F8, Cz, T3, and T4 according to the 10-20 system. Below VT auditory midlatency responses (MLRs) were observed. Above VT two additional potentials appeared: a positivity at about 10 ms (P10) which was maximal at Cz, and a negativity at about 15 ms (N15) which was maximal at Fpz. Extrapolation of the growth functions for the P10 and N15 indicated a threshold close to VT, consistent with a vestibular origin of these potentials. Given the low threshold of vestibular acoustic sensitivity it is possible that this mode may make a contribution to the detection of and affective responses to loud low frequency sounds. The evoked potentials may also have application as a noninvasive and nontraumatic test of vestibular projections to the cortex.

  18. [Local application of simvastatin to rat incisor sockets augments bone].

    PubMed

    Nishimura, Kenichi

    2008-03-01

    Decrease of the alveolar ridge after tooth extraction causes difficulties in prosthodontic treatment, especially in implant supported prostheses. Statins, which are inhibitors of cholesterol synthesis and therapeutic drugs for hypercholestemia, stimulate BMP-2 expression in osteoblasts. The purpose of the present study was to examine how local application of simvastatin, one of the statins, to the tooth socket after tooth extraction affects alveolar bone. A mixture of lactic acid/glycolic acid copolymer (PLGA), alpha-tricalcium phosphate (alpha-TCP), calcium carbonate was prepared as a carrier for simvastatin. Ninety-six male Wistar rats, 10 weeks old, were used. After right mandibular incisor extraction, they were divided into eight groups and tooth sockets were treated differently: no treatment (control), PLGA carrier only, or PLGA containing 0.1, 0.25, 0.5, 1.0, 2.0, and 4.0 mg simvastatin, respectively. They were sacrificed at 4 and 8 weeks. Bone mineral content (BMC) of the alveolar ridge was measured with dual-energy X-ray absorptiometry and histological analyses were performed. All groups treated with simvastatin showed higher BMC compared to the control group and PLGA carrier group at 4 and 8 weeks. Histological analyses revealed that the thickness of cortical bone of the statin group increased compared to the control group at 4 and 8 weeks; however, newly-formed bone in the tooth socket of the statin group was less than in those of the control group and PLGA carrier group. The results of this study show that local application of simvastatin may enhance bone formation and preserve the alveolar ridge after tooth extraction. PMID:18421951

  19. Research Sees Potential to Make Bone, Muscle from Human Stem Cells

    MedlinePlus

    ... Sees Potential to Make Bone, Muscle From Human Stem Cells Could be a major advance for regenerative medicine, ... muscle and 10 other cells types from human stem cells within a matter of days. The researchers from ...

  20. Bone marrow stem cell as a potential treatment for diabetes.

    PubMed

    Li, Ming; Ikehara, Susumu

    2013-01-01

    Diabetes mellitus (DM) is a group of metabolic diseases in which a person has high blood glucose levels resulting from defects in insulin secretion and insulin action. The chronic hyperglycemia damages the eyes, kidneys, nerves, heart, and blood vessels. Curative therapies mainly include diet, insulin, and oral hypoglycemic agents. However, these therapies fail to maintain blood glucose levels in the normal range all the time. Although pancreas or islet-cell transplantation achieves better glucose control, a major obstacle is the shortage of donor organs. Recently, research has focused on stem cells which can be classified into embryonic stem cells (ESCs) and tissue stem cells (TSCs) to generate functional β cells. TSCs include the bone-marrow-, liver-, and pancreas-derived stem cells. In this review, we focus on treatment using bone marrow stem cells for type 1 and 2 DM. PMID:23671865

  1. Bone Tumor Environment as a Potential Therapeutic Target in Ewing Sarcoma

    PubMed Central

    Redini, Françoise; Heymann, Dominique

    2015-01-01

    Ewing sarcoma is the second most common pediatric bone tumor, with three cases per million worldwide. In clinical terms, Ewing sarcoma is an aggressive, rapidly fatal malignancy that mainly develops not only in osseous sites (85%) but also in extra-skeletal soft tissue. It spreads naturally to the lungs, bones, and bone marrow with poor prognosis in the two latter cases. Bone lesions from primary or secondary (metastases) tumors are characterized by extensive bone remodeling, more often due to osteolysis. Osteoclast activation and subsequent bone resorption are responsible for the clinical features of bone tumors, including pain, vertebral collapse, and spinal cord compression. Based on the “vicious cycle” concept of tumor cells and bone resorbing cells, drugs, which target osteoclasts, may be promising agents as adjuvant setting for treating bone tumors, including Ewing sarcoma. There is also increasing evidence that cellular and molecular protagonists present in the bone microenvironment play a part in establishing a favorable “niche” for tumor initiation and progression. The purpose of this review is to discuss the potential therapeutic value of drugs targeting the bone tumor microenvironment in Ewing sarcoma. The first part of the review will focus on targeting the bone resorbing function of osteoclasts by means of bisphosphonates or drugs blocking the pro-resorbing cytokine receptor activator of NF-kappa B ligand. Second, the role of this peculiar hypoxic microenvironment will be discussed in the context of resistance to chemotherapy, escape from the immune system, or neo-angiogenesis. Therapeutic interventions based on these specificities could be then proposed in the context of Ewing sarcoma. PMID:26779435

  2. Bone Tumor Environment as a Potential Therapeutic Target in Ewing Sarcoma.

    PubMed

    Redini, Françoise; Heymann, Dominique

    2015-01-01

    Ewing sarcoma is the second most common pediatric bone tumor, with three cases per million worldwide. In clinical terms, Ewing sarcoma is an aggressive, rapidly fatal malignancy that mainly develops not only in osseous sites (85%) but also in extra-skeletal soft tissue. It spreads naturally to the lungs, bones, and bone marrow with poor prognosis in the two latter cases. Bone lesions from primary or secondary (metastases) tumors are characterized by extensive bone remodeling, more often due to osteolysis. Osteoclast activation and subsequent bone resorption are responsible for the clinical features of bone tumors, including pain, vertebral collapse, and spinal cord compression. Based on the "vicious cycle" concept of tumor cells and bone resorbing cells, drugs, which target osteoclasts, may be promising agents as adjuvant setting for treating bone tumors, including Ewing sarcoma. There is also increasing evidence that cellular and molecular protagonists present in the bone microenvironment play a part in establishing a favorable "niche" for tumor initiation and progression. The purpose of this review is to discuss the potential therapeutic value of drugs targeting the bone tumor microenvironment in Ewing sarcoma. The first part of the review will focus on targeting the bone resorbing function of osteoclasts by means of bisphosphonates or drugs blocking the pro-resorbing cytokine receptor activator of NF-kappa B ligand. Second, the role of this peculiar hypoxic microenvironment will be discussed in the context of resistance to chemotherapy, escape from the immune system, or neo-angiogenesis. Therapeutic interventions based on these specificities could be then proposed in the context of Ewing sarcoma. PMID:26779435

  3. The application of induced pluripotent stem cells for bone regeneration: current progress and prospects.

    PubMed

    Teng, Songsong; Liu, Chaoxu; Krettek, Christian; Jagodzinski, Michael

    2014-08-01

    Loss of healthy bone tissue and dysosteogenesis are still common and significant problems in clinics. Cell-based therapy using mesenchymal stem cells (MSCs) has been performed in patients for quite some time, but the inherent drawbacks of these cells, such as the reductions in proliferation rate and osteogenic differentiation potential that occur with aging, greatly limit their further application. Moreover, embryonic stem cells (ESCs) have brought new hope to osteoregenerative medicine because of their full pluripotent differentiation potential and excellent performance in bone regeneration. However, the ethical issues involved in destroying human embryos and the immune reactions that occur after transplantation are two major stumbling blocks impeding the clinical application of ESCs. Instead, induced pluripotent stem cells (iPSCs), which are ESC-like pluripotent cells that are reprogrammed from adult somatic cells using defined transcription factors, are considered a more promising source of cells for regenerative medicine because they present no ethical or immunological issues. Here, we summarize the primary technologies for generating iPSCs and the biological properties of these cells, review the current advances in iPSC-based bone regeneration and, finally, discuss the remaining challenges associated with these cells, particularly safety issues and their potential application for osteoregenerative medicine. PMID:24102431

  4. Development of an angiogenesis-promoting microvesicle-alginate-polycaprolactone composite graft for bone tissue engineering applications.

    PubMed

    Xie, Hui; Wang, Zhenxing; Zhang, Liming; Lei, Qian; Zhao, Aiqi; Wang, Hongxiang; Li, Qiubai; Chen, Zhichao; Zhang, WenJie

    2016-01-01

    One of the major challenges of bone tissue engineering applications is to construct a fully vascularized implant that can adapt to hypoxic environments in vivo. The incorporation of proangiogenic factors into scaffolds is a widely accepted method of achieving this goal. Recently, the proangiogenic potential of mesenchymal stem cell-derived microvesicles (MSC-MVs) has been confirmed in several studies. In the present study, we incorporated MSC-MVs into alginate-polycaprolactone (PCL) constructs that had previously been developed for bone tissue engineering applications, with the aim of promoting angiogenesis and bone regeneration. MSC-MVs were first isolated from the supernatant of rat bone marrow-derived MSCs and characterized by scanning electron microscopic, confocal microscopic, and flow cytometric analyses. The proangiogenic potential of MSC-MVs was demonstrated by the stimulation of tube formation of human umbilical vein endothelial cells in vitro. MSC-MVs and osteodifferentiated MSCs were then encapsulated with alginate and seeded onto porous three-dimensional printed PCL scaffolds. When combined with osteodifferentiated MSCs, the MV-alginate-PCL constructs enhanced vessel formation and tissue-engineered bone regeneration in a nude mouse subcutaneous bone formation model, as demonstrated by micro-computed tomographic, histological, and immunohistochemical analyses. This MV-alginate-PCL construct may offer a novel, proangiogenic, and cost-effective option for bone tissue engineering. PMID:27231660

  5. Development of an angiogenesis-promoting microvesicle-alginate-polycaprolactone composite graft for bone tissue engineering applications

    PubMed Central

    Zhang, Liming; Lei, Qian; Zhao, Aiqi; Wang, Hongxiang; Li, Qiubai

    2016-01-01

    One of the major challenges of bone tissue engineering applications is to construct a fully vascularized implant that can adapt to hypoxic environments in vivo. The incorporation of proangiogenic factors into scaffolds is a widely accepted method of achieving this goal. Recently, the proangiogenic potential of mesenchymal stem cell-derived microvesicles (MSC-MVs) has been confirmed in several studies. In the present study, we incorporated MSC-MVs into alginate-polycaprolactone (PCL) constructs that had previously been developed for bone tissue engineering applications, with the aim of promoting angiogenesis and bone regeneration. MSC-MVs were first isolated from the supernatant of rat bone marrow-derived MSCs and characterized by scanning electron microscopic, confocal microscopic, and flow cytometric analyses. The proangiogenic potential of MSC-MVs was demonstrated by the stimulation of tube formation of human umbilical vein endothelial cells in vitro. MSC-MVs and osteodifferentiated MSCs were then encapsulated with alginate and seeded onto porous three-dimensional printed PCL scaffolds. When combined with osteodifferentiated MSCs, the MV-alginate-PCL constructs enhanced vessel formation and tissue-engineered bone regeneration in a nude mouse subcutaneous bone formation model, as demonstrated by micro-computed tomographic, histological, and immunohistochemical analyses. This MV-alginate-PCL construct may offer a novel, proangiogenic, and cost-effective option for bone tissue engineering. PMID:27231660

  6. Fabrication and characterization of a novel carbon fiber-reinforced calcium phosphate silicate bone cement with potential osteo-inductivity.

    PubMed

    Zheng, Jiangjiang; Xiao, Yu; Gong, Tianxing; Zhou, Shuxin; Troczynski, Tom; Yang, Quanzu; Bao, Chongyun; Xu, Xiaoming

    2016-02-01

    The repair of bone defects is still a pressing challenge in clinics. Injectable bone cement is regarded as a promising material to solve this problem because of its special self-setting property. Unfortunately, its poor mechanical conformability, unfavorable osteo-genesis ability and insufficient osteo-inductivity seriously limit its clinical application. In this study, novel experimental calcium phosphate silicate bone cement reinforced by carbon fibers (CCPSC) was fabricated and characterized. First, a compressive strength test and cell culture study were carried out. Then, the material was implanted into the femoral epiphysis of beagle dogs to further assess its osteo-conductivity using a micro-computed tomography scan and histological analysis. In addition, we implanted CCPSC into the beagles' intramuscular pouches to perform an elementary investigation of its osteo-inductivity. The results showed that incorporation of carbon fibers significantly improved its mechanical properties. Meanwhile, CCPSC had better biocompatibility to activate cell adhesion as well as proliferation than poly-methyl methacrylate bone cement based on the cell culture study. Moreover, pronounced biodegradability and improved osteo-conductivity of CCPSC could be observed through the in vivo animal study. Finally, a small amount of osteoid was found at the heterotopic site one month after implantation which indicated potential osteo-inductivity of CCPSC. In conclusion, the novel CCPSC shows promise as a bioactive bone substitute in certain load-bearing circumstances. PMID:26695113

  7. Bone-cartilage interface crosstalk in osteoarthritis: potential pathways and future therapeutic strategies.

    PubMed

    Yuan, X L; Meng, H Y; Wang, Y C; Peng, J; Guo, Q Y; Wang, A Y; Lu, S B

    2014-08-01

    Currently, osteoarthritis (OA) is considered a disease of the entire joint, which is not simply a process of wear and tear but rather abnormal remodelling and joint failure of an organ. The bone-cartilage interface is therefore a functioning synergistic unit, with a close physical association between subchondral bone and cartilage suggesting the existence of biochemical and molecular crosstalk across the OA interface. The crosstalk at the bone-cartilage interface may be elevated in OA in vivo and in vitro. Increased vascularisation and formation of microcracks associated with abnormal bone remodelling in joints during OA facilitate molecular transport from cartilage to bone and vice versa. Recent reports suggest that several critical signalling pathways and biological factors are key regulators and activate cellular and molecular processes in crosstalk among joint compartments. Therapeutic interventions including angiogenesis inhibitors, agonists/antagonists of molecules and drugs targeting bone remodelling are potential candidates for this interaction. This review summarised the premise for the presence of crosstalk in bone-cartilage interface as well as the current knowledge of the major signalling pathways and molecular interactions that regulate OA progression. A better understanding of crosstalk in bone-cartilage interface may lead to development of more effective strategies for treating OA patients. PMID:24928319

  8. Potential of targeted drug delivery system for the treatment of bone metastasis.

    PubMed

    Vinay, Raichur; KusumDevi, V

    2016-01-01

    Bone metastasis is a devastating complication of cancer that requires an immediate attention. Although our understanding of the metastatic process has improved over the years, yet a number of questions still remain unanswered, and more research is required for complete understanding of the skeletal consequences of metastasis. Furthermore, as no effective treatments are available for some of the most common skeleton disorders such as arthritis, osteoarthritis, osteosarcoma and metastatic bone cancer, there is an urgent need to develop new drugs and drug delivery systems for safe and efficient clinical treatments. Hence this article describes the potential of targeted delivery platforms aimed specifically at bone metastasized tumors. The review gives a brief understanding of the proposed mechanisms of metastasis and focuses primarily on the targeting moieties such as bisphosphonates, which represent the current gold standard in bone metastasis therapies. Special focus has been given to the targeted nanoparticulate systems for treating bone metastasis and its future. Also highlighted are some of the therapeutic targets that can be exploited for designing therapies for bone metastasis. Some of the patented molecules for bone metastasis prevention and treatment have also been discussed. Recently proposed HIFU-CHEM, which utilizes High Intensity Focused ultrasound (HIFU) guided by MRI in combination with temperature-sensitive nanomedicines has also been briefed. The study has been concluded with a focus on the innovations requiring an immediate attention that could improve the treatment modality of bone metastasis. PMID:24839990

  9. Potential of pigment epithelium-derived factor (PEDF) as a bone regenerative biopharmaceutical.

    PubMed

    Lee, P X; Dass, C R

    2016-04-01

    Bone is very much a dynamic tissue, capable of various functions not limited to protection of the marrow, serving as a reservoir for calcium, maintaining posture and facilitating mobility. It is also a tissue that is fully capable of regenerating itself at most stages of life, with a diminishing capacity with increasing age. Bone defects can arise from a variety of factors not limited to bone tumours and fractures. At present, clinically, most diseased bone is removed and the patient fitted with prosthetics, with use of certain factors such as bone morphogenetic proteins (BMPs) to aid healing. Recently, the protein pigment epithelium-derived factor (PEDF) has been found to have favourable effects on bone regeneration, which is reviewed here. Numerous studies have shown the potential of PEDF in vitro, with increasing reports of success in small animal models of bone trauma. This review puts forward the advantages, and some disadvantages, in the use of PEDF as a biopharmaceutical for bone regeneration. PMID:27209693

  10. Biocomposite macroporous cryogels as potential carrier scaffolds for bone active agents augmenting bone regeneration.

    PubMed

    Raina, Deepak Bushan; Isaksson, Hanna; Teotia, Arun Kumar; Lidgren, Lars; Tägil, Magnus; Kumar, Ashok

    2016-08-10

    Osteoinduction can be enhanced by combining scaffolds with bone morphogenic protein-2 (BMP-2). However, BMP's are known to also cause bone resorption. This can be controlled using bisphosphonates like zoledronic acid (ZA). In this study, we produced two different scaffolds containing silk-fibroin, chitosan, agarose and hydroxyapatite (HA) with and without bioactive glass. The aims of the study were to fabricate, physico-chemically characterize and evaluate the carrier properties of the scaffolds for recombinant human BMP-2 (rhBMP-2) and ZA. Scaffolds were characterized using various methods to confirm their composition. During cell-material interactions, both scaffolds exhibited gradual but sustained proliferation of both C2C12 and MSCs for a period of 6weeks with augmentative effects on their phenotype indicated by elevated levels of alkaline phosphatase (ALP) cuing towards osteogenic differentiation. In-vitro effects of rhBMP-2 and ZA contained within both the scaffolds was assessed on MC3T3 preosteoblast cells and the results show a significant increase in the ALP activity of the cells seeded on scaffolds with rhBMP-2. Further, the scaffold with both HA and bioactive glass was considered for the animal study. In-vitro, this scaffold released nearly 25% rhBMP-2 in 21-days and the addition of ZA did not affect the release. In the animal study, the scaffolds were combined with rhBMP-2 and ZA, rhBMP-2 or implanted alone in an ectopic muscle pouch model. Significantly higher bone formation was observed in the scaffold loaded with both rhBMP-2 and ZA as seen from micro-computed tomography, histomorphometry and energy dispersive X-ray spectroscopy. PMID:27252151

  11. Application of high resolution pQCT analysis for the assessment of a bone lesion: a technical note.

    PubMed

    Rubinacci, A; Tresoldi, D; Villa, I; Rizzo, G; Gaudio, D; De Angelis, D; Gibelli, D; Cattaneo, C

    2015-01-01

    Peripheral quantitative computed tomography (pQCT) has found new fields of application in bone medicine, but none of them concerns the forensic practice. This study exposes the potential of pQCT applied to a penetrating lesion in a vertebral body. A pQCT scanner was used for the measurements (XCT Research SA+; Stratec Medizintechnik GmbH, Pforzheim, Germany). A more precise reconstruction of the path of the lesion within the trabecular bone was reached, with more details concerning the morphological characteristics of the lesion inside the vertebral body, and the elaboration of a 3D model was created, which allowed the operator to define the volume of the lack of tissues related to the lesion. The application of pQCT scan proved to be a potentially useful tool for the assessment of bone lesions, although further studies are needed in order to verify its applicability to forensic context. PMID:25258096

  12. Biological Events in Periodontal Ligament and Alveolar Bone Associated with Application of Orthodontic Forces

    PubMed Central

    Feller, L.; Khammissa, R. A. G.; Schechter, I.; Thomadakis, G.; Fourie, J.; Lemmer, J.

    2015-01-01

    Orthodontic force-induced stresses cause dynamic alterations within the extracellular matrix and within the cytoskeleton of cells in the periodontal ligament and alveolar bone, mediating bone remodelling, ultimately enabling orthodontic tooth movement. In the periodontal ligament and alveolar bone, the mechanically induced tensile strains upregulate the expression of osteogenic genes resulting in bone formation, while mechanically induced compressive strains mediate predominantly catabolic tissue changes and bone resorption. In this review article we summarize some of the currently known biological events occurring in the periodontal ligament and in the alveolar bone in response to application of orthodontic forces and how these facilitate tooth movement. PMID:26421314

  13. Bone morphogenetic protein-2: a potential regulator in scleral remodeling

    PubMed Central

    Hu, Jianmin; Cui, Dongmei; Yang, Xiao; Wang, Shaowei; Hu, Shoulong; Li, Chuanxu

    2008-01-01

    Purpose Bone morphogenetic protein 2 (BMP-2) is a member of the main subgroup of bone morphogenetic proteins within the transforming growth factor-β superfamily. BMP-2 is involved in numerous cellular functions including development, cell proliferation, apoptosis, and extracellular matrix synthesis. We examined BMP-2 expression in human scleral fibroblasts (HSF) and assessed the effects of recombinant human BMP-2 (rhBMP-2) on HSF proliferation, matrix metalloproteinase-2 (MMP-2), and tissue inhibitor of metalloproteinase-2 (TIMP-2). Methods We used confocal fluorescence microscopy (CFM) to study BMP-2 distribution in HSF cells and frozen human scleral sections. The influence of rhBMP-2 on cell proliferation at different concentrations (0 ng/ml, 1 ng/ml, 10 ng/ml, and 100 ng/ml) was evaluated by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The effects of rhBMP-2 on the cell cycle were investigated with flow cytometric analysis. Reverse transcription polymerase chain reaction (RT–PCR) and enzyme-linked immunosorbent assay (ELISA) were used to examine MMP-2 and TIMP-2 mRNAs and secreted proteins in HSF that were incubated with rhBMP-2. Results BMP-2 protein expression from human sclera was confirmed by CFM. Cell proliferation was significantly increased with 100 ng/ml rhBMP-2 in a time-dependent manner (p<0.05). The HSF cell cycle moved to the S and S+G2M phases after rhBMP-2 stimulation at 100 ng/ml compared to normal cells (p<0.05). TIMP-2 mRNA levels were significantly increased in HSF incubated for 24 h with 100 ng/ml rhBMP-2 (p<0.01). A 48 h incubation with 10 ng/ml or 100 ng/ml rhBMP-2 resulted in significantly increased TIMP-2 mRNA and protein expression and significantly decreased MMP-2 mRNA expression (p<0.01) while MMP-2 protein expression significantly decreased at 100 ng/ml rhBMP-2 (p<0.01). Conclusions Human sclera fibroblasts expressed BMP-2, which promoted cell proliferation, and elicited changes in MMP-2 and TIMP-2

  14. Donor age and cell passage affects differentiation potential of murine bone marrow-derived stem cells

    PubMed Central

    Kretlow, James D; Jin, Yu-Qing; Liu, Wei; Zhang, Wen Jie; Hong, Tan-Hui; Zhou, Guangdong; Baggett, L Scott; Mikos, Antonios G; Cao, Yilin

    2008-01-01

    Background Bone marrow-derived mesenchymal stem cells (BMSCs) are a widely researched adult stem cell population capable of differentiation into various lineages. Because many promising applications of tissue engineering require cell expansion following harvest and involve the treatment of diseases and conditions found in an aging population, the effect of donor age and ex vivo handling must be understood in order to develop clinical techniques and therapeutics based on these cells. Furthermore, there currently exists little understanding as to how these two factors may be influenced by one another. Results Differences in the adipogenic, chondrogenic, and osteogenic differentiation capacity of murine MSCs harvested from donor animals of different age and number of passages of these cells were observed. Cells from younger donors adhered to tissue culture polystyrene better and proliferated in greater number than those from older animals. Chondrogenic and osteogenic potential decreased with age for each group, and adipogenic differentiation decreased only in cells from the oldest donors. Significant decreases in differentiation potentials due to passage were observed as well for osteogenesis of BMSCs from the youngest donors and chondrogenesis of the cells from the oldest donors. Conclusion Both increasing age and the number of passages have lineage dependent effects on BMSC differentiation potential. Furthermore, there is an obvious interplay between donor age and cell passage that in the future must be accounted for when developing cell-based therapies for clinical use. PMID:18957087

  15. Increased bone formation in a rabbit long-bone defect model after single local and single systemic application of erythropoietin.

    PubMed

    Omlor, Georg W; Kleinschmidt, Kerstin; Gantz, Simone; Speicher, Anja; Guehring, Thorsten; Richter, Wiltrud

    2016-08-01

    Background and purpose - Delayed bone healing with non-union is a common problem. Further options to increase bone healing together with surgery are needed. We therefore evaluated a 1-dose single application of erythropoietin (EPO), applied either locally to the defect or systemically during surgery, in a critical-size rabbit long-bone defect. Material and methods - 19 New Zealand White rabbits received a 15-mm defect in the radius diaphysis. An absorbable gelatin sponge was soaked with saline (control group and systemic treatment group) or EPO (local treatment group) and implanted into the gap. The systemic treatment group received EPO subcutaneously. In vivo micro-CT analysis was performed 4, 8, and 12 weeks postoperatively. Vascularization was evaluated histologically. Results - Semiquantitative histomorphometric and radiological evaluation showed increased bone formation (2.3- to 2.5-fold) in both treatment groups after 12 weeks compared to the controls. Quantitative determination of bone volume and tissue volume showed superior bone healing after EPO treatment at all follow-up time points, with the highest values after 12 weeks in locally treated animals (3.0- to 3.4-fold). More vascularization was found in both EPO treatment groups. Interpretation - Initial single dosing with EPO was sufficient to increase bone healing substantially after 12 weeks of follow-up. Local application inside the defect was most effective, and it can be administered directly during surgery. Apart from effects on ossification, systemic and local EPO treatment leads to increased callus vascularization. PMID:27348783

  16. Development of a biodegradable bone cement for craniofacial applications.

    PubMed

    Henslee, Allan M; Gwak, Dong-Ho; Mikos, Antonios G; Kasper, F Kurtis

    2012-09-01

    This study investigated the formulation of a two-component biodegradable bone cement comprising the unsaturated linear polyester macromer poly(propylene fumarate) (PPF) and crosslinked PPF microparticles for use in craniofacial bone repair applications. A full factorial design was employed to evaluate the effects of formulation parameters such as particle weight percentage, particle size, and accelerator concentration on the setting and mechanical properties of crosslinked composites. It was found that the addition of crosslinked microparticles to PPF macromer significantly reduced the temperature rise upon crosslinking from 100.3°C ± 21.6°C to 102.7°C ± 49.3°C for formulations without microparticles to 28.0°C ± 2.0°C to 65.3°C ± 17.5°C for formulations with microparticles. The main effects of increasing the particle weight percentage from 25 to 50% were to significantly increase the compressive modulus by 37.7 ± 16.3 MPa, increase the compressive strength by 2.2 ± 0.5 MPa, decrease the maximum temperature by 9.5°C ± 3.7°C, and increase the setting time by 0.7 ± 0.3 min. Additionally, the main effects of increasing the particle size range from 0-150 μm to 150-300 μm were to significantly increase the compressive modulus by 31.2 ± 16.3 MPa and the compressive strength by 1.3 ± 0.5 MPa. However, the particle size range did not have a significant effect on the maximum temperature and setting time. Overall, the composites tested in this study were found to have properties suitable for further consideration in craniofacial bone repair applications. PMID:22499285

  17. Potential medical applications of TAE

    NASA Technical Reports Server (NTRS)

    Fahy, J. Ben; Kaucic, Robert; Kim, Yongmin

    1986-01-01

    In cooperation with scientists in the University of Washington Medical School, a microcomputer-based image processing system for quantitative microscopy, called DMD1 (Digital Microdensitometer 1) was constructed. In order to make DMD1 transportable to different hosts and image processors, we have been investigating the possibility of rewriting the lower level portions of DMD1 software using Transportable Applications Executive (TAE) libraries and subsystems. If successful, we hope to produce a newer version of DMD1, called DMD2, running on an IBM PC/AT under the SCO XENIX System 5 operating system, using any of seven target image processors available in our laboratory. Following this implementation, copies of the system will be transferred to other laboratories with biomedical imaging applications. By integrating those applications into DMD2, we hope to eventually expand our system into a low-cost general purpose biomedical imaging workstation. This workstation will be useful not only as a self-contained instrument for clinical or research applications, but also as part of a large scale Digital Imaging Network and Picture Archiving and Communication System, (DIN/PACS). Widespread application of these TAE-based image processing and analysis systems should facilitate software exchange and scientific cooperation not only within the medical community, but between the medical and remote sensing communities as well.

  18. Dimethyloxaloylglycine Increases the Bone Healing Capacity of Adipose-Derived Stem Cells by Promoting Osteogenic Differentiation and Angiogenic Potential

    PubMed Central

    Ding, Hao; Gao, You-Shui; Wang, Yang; Hu, Chen

    2014-01-01

    Hypoxia inducible factor-1α (HIF-1α) plays an important role in angiogenesis-osteogenesis coupling during bone regeneration, which can enhance the bone healing capacity of mesenchymal stem cells (MSCs) by improving their osteogenic and angiogenic activities. Previous studies transduced the HIF-1α gene into MSCs with lentivirus vectors to improve their bone healing capacity. However, the risks due to lentivirus vectors, such as tumorigenesis, should be considered before clinical application. Dimethyloxaloylglycine (DMOG) is a cell-permeable prolyl-4-hydroxylase inhibitor, which can activate the expression of HIF-1α in cells at normal oxygen tension. Therefore, DMOG is expected to be an alternative strategy for enhancing HIF-1α expression in cells. In this study, we explored the osteogenic and angiogenic activities of adipose-derived stem cells (ASCs) treated with different concentrations of DMOG in vitro, and the bone healing capacity of DMOG-treated ASCs combined with hydrogels for treating critical-sized calvarial defects in rats. The results showed that DMOG had no obvious cytotoxic effects on ASCs and could inhibit the death of ASCs induced by serum deprivation. DMOG markedly increased vascular endothelial growth factor production in ASCs in a dose-dependent manner and improved the osteogenic differentiation potential of ASCs by activating the expression of HIF-1α. Rats with critical-sized calvarial defects treated with hydrogels containing DMOG-treated ASCs had more bone regeneration and new vessel formation than the other groups. Therefore, we believe that DMOG enhanced the angiogenic and osteogenic activity of ASCs by activating the expression of HIF-1α, thereby improving the bone healing capacity of ASCs in rat critical-sized calvarial defects. PMID:24328551

  19. Adult mesenchymal stem cells: differentiation potential and therapeutic applications.

    PubMed

    Jackson, L; Jones, D R; Scotting, P; Sottile, V

    2007-01-01

    Adult mesenchymal stem cells (MSCs) are a population of multipotent cells found primarily in the bone marrow. They have long been known to be capable of osteogenic, adipogenic and chondrogenic differentiation and are currently the subject of a number of trials to assess their potential use in the clinic. Recently, the plasticity of these cells has come under close scrutiny as it has been suggested that they may have a differentiation potential beyond the mesenchymal lineage. Myogenic and in particular cardiomyogenic potential has been shown in vitro. MSCs have also been shown to have the ability to form neural cells both in vitro and in vivo, although the molecular mechanisms underlying these apparent transdifferentiation events are yet to be elucidated. We describe here the cellular characteristics and differentiation potential of MSCs, which represent a promising stem cell population for future applications in regenerative medicine. PMID:17495381

  20. Processing and characterization of diatom nanoparticles and microparticles as potential source of silicon for bone tissue engineering.

    PubMed

    Le, Thi Duy Hanh; Bonani, Walter; Speranza, Giorgio; Sglavo, Vincenzo; Ceccato, Riccardo; Maniglio, Devid; Motta, Antonella; Migliaresi, Claudio

    2016-02-01

    Silicon plays an important role in bone formation and maintenance, improving osteoblast cell function and inducing mineralization. Often, bone deformation and long bone abnormalities have been associated with silica/silicon deficiency. Diatomite, a natural deposit of diatom skeleton, is a cheap and abundant source of biogenic silica. The aim of the present study is to validate the potential of diatom particles derived from diatom skeletons as silicon-donor materials for bone tissue engineering applications. Raw diatomite (RD) and calcined diatomite (CD) powders were purified by acid treatments, and diatom microparticles (MPs) and nanoparticles (NPs) were produced by fragmentation of purified diatoms under alkaline conditions. The influence of processing on the surface chemical composition of purified diatomites was evaluated by X-ray photoelectron spectroscopy (XPS). Diatoms NPs were also characterized in terms of morphology and size distribution by transmission electron microscopy (TEM) and Dynamic light scattering (DLS), while diatom MPs morphology was analyzed by scanning electron microscopy (SEM). Surface area and microporosity of the diatom particles were evaluated by nitrogen physisorption methods. Release of silicon ions from diatom-derived particles was demonstrated using inductively coupled plasma optical emission spectrometry (ICP/OES); furthermore, silicon release kinetic was found to be influenced by diatomite purification method and particle size. Diatom-derived microparticles (MPs) and nanoparticles (NPs) showed limited or no cytotoxic effect in vitro depending on the administration conditions. PMID:26652398

  1. Bone ingrowth: an application of the boundary element method to bone remodeling at the implant interface.

    PubMed

    Sadegh, A M; Luo, G M; Cowin, S C

    1993-02-01

    Surface bone remodeling theory and the boundary element method are employed to investigate the microstructural remodeling of bone at the bone-implant interface. Three situations are considered: remodeling-induced penetration between the screw threads of an implanted screw, penetration of bone tissue into a slot or cavity in an implant, and the interaction of individual trabeculae in the remodeling processes near an implant. For each case the bone ingrowth is determined as a function of the geometry and the applied load. PMID:8429059

  2. Biomechanical aspects of bone microstructure in vertebrates: potential approach to palaeontological investigations.

    PubMed

    Mishra, S

    2009-11-01

    Biomechanical or biophysical principles can be applied to study biological structures in their modern or fossil form. Bone is an important tissue in paleontological studies as it is a commonly preserved element in most fossil vertebrates, and can often allow its microstructures such as lacuna and canaliculi to be studied in detail. In this context, the principles of Fluid Mechanics and Scaling Laws have been previously applied to enhance the understanding of bone microarchitecture and their implications for the evolution of hydraulic structures to transport fluid. It has been shown that the microstructure of bone has evolved to maintain efficient transport between the nutrient supply and cells, the living components of the tissue. Application of the principle of minimal expenditure of energy to this analysis shows that the path distance comprising five or six lamellar regions represents an effective limit for fluid and solute transport between the nutrient supply and cells; beyond this threshold, hydraulic resistance in the network increases and additional energy expenditure is necessary for further transportation. This suggests an optimization of the size of the bone's building blocks (such as osteon or trabecular thickness) to meet the metabolic demand concomitant to minimal expenditure of energy. This biomechanical aspect of bone microstructure is corroborated from the ratio of osteon to Haversian canal diameters and scaling constants of several mammals considered in this study. This aspect of vertebrate bone microstructure and physiology may provide a basis of understanding of the form and function relationship in both extinct and extant taxa. PMID:20009272

  3. Corals and Their Potential Applications to Integrative Medicine

    PubMed Central

    Cooper, Edwin L.; Hirabayashi, Kyle; Strychar, Kevin B.; Sammarco, Paul W.

    2014-01-01

    Over the last few years, we have pursued the use and exploitation of invertebrate immune systems, most notably their humoral products, to determine what effects their complex molecules might exert on humans, specifically their potential for therapeutic applications. This endeavor, called “bioprospecting,” is an emerging necessity for biomedical research. In order to treat the currently “untreatable,” or to discover more efficient treatment modalities, all options and potential sources must be exhausted so that we can provide the best care to patients, that is, proceed from forest and ocean ecosystems through the laboratory to the bedside. Here, we review current research findings that have yielded therapeutic benefits, particularly as derived from soft and hard corals. Several applications have already been demonstrated, including anti-inflammatory properties, anticancer properties, bone repair, and neurological benefits. PMID:24757491

  4. Functionalized carbon nanotubes for potential medicinal applications

    PubMed Central

    Zhang, Yi; Bai, Yuhong; Yan, Bing

    2016-01-01

    Functionalized carbon nanotubes display unique properties that enable a variety of medicinal applications, including the diagnosis and treatment of cancer, infectious diseases and central nervous system disorders, and applications in tissue engineering. These potential applications are particularly encouraged by their ability to penetrate biological membranes and relatively low toxicity. PMID:20451656

  5. Hydroxyapatite-titanium bulk composites for bone tissue engineering applications.

    PubMed

    Kumar, Alok; Biswas, Krishanu; Basu, Bikramjit

    2015-02-01

    The research work on bulk hydroxyapatite (HA)-based composites are driven by the need to develop biomaterials with better mechanical properties without compromising its bioactivity and biocompatibility properties. Despite several years of research, the mechanical properties of the HA-based composites still need to be enhanced to match the properties of natural cortical bone. In this regard, the scope of this review on the HA-based bulk biomaterials is limited to the processing and the mechanical as well as biocompatibility properties for bone tissue engineering applications of a model system that is hydroxyapatite-titanium (HA-Ti) bulk composites. It will be discussed in this review how HA-Ti based bulk composites can be processed to have better fracture toughness and strength without compromising biocompatibility. The advantages of the functionally gradient materials to integrate the mechanical and biocompatibility properties is a promising approach in hard tissue engineering and has been emphasized here in reference to the limited literature reports. On the biomaterials fabrication aspect, the recent results are discussed to demonstrate that advanced manufacturing techniques, like spark plasma sintering can be adopted as a processing route to restrict the sintering reactions, while enhancing the mechanical properties. Various toughening mechanisms related to careful tailoring of microstructure are discussed. The in vitro cytocompatibilty, cell fate processes as well as in vivo biocompatibility results are also reviewed and the use of flow cytometry to quantify in vitro cell fate processes is being emphasized. PMID:24737723

  6. Potential applications of satellite navigation

    NASA Astrophysics Data System (ADS)

    Schaenzer, G.

    The applicability of Navstar GPS to civil air navigation is discussed. The accuracy of current air-navigation systems is reviewed; the basic principle and accuracy of GPS navigation are characterized; the relatively low cost of GPS receiving equipment is pointed out; and particular attention is given to hybrid systems combining GPS with inertial navigation. It is predicted that CAT III landings will be possible using such hybrid systems when the GPS satellites are fully deployed, even without access to the military GPS code. Techniques for GPS-based precision landings, reduced-noise landings, landings on parallel runways, control of taxiing maneuvers, and aircraft-based geodetic measurements are briefly described and illustrated with diagrams.

  7. Heterotopic implantation of autologous bone marrow in rock pigeons (Columba livia): possible applications in avian bone grafting.

    PubMed

    Sanaei, M Reza; Abu, Jalila; Nazari, Mojgan; Faiz, Nik Mohd; Bakar, Mohd Zuki Abu; Allaudin, Zeenathul N

    2011-12-01

    Autologous bone marrow, alone or as a composite marrow graft, has received much attention in various species. To assess the potential osteogenicity of autologous, extramedullary bone marrow implants in an avian model, 24 adult pigeons (Columba livia) were given intramuscular implantations of autologous marrow aspirated from the medial tibiotarsus. Birds were euthanatized at 1, 4, 6, 8, 10, and 12 weeks after surgery to evaluate whether ectopic bone had formed at the implant sites. Primary evaluations by in situ radiography and postmortem histologic examinations showed no evidence of bone formation. Further evaluation with histologic scores and histomorphometry revealed a significantly increased rate of angiogenesis at the implant sites by the sixth and tenth week postimplantation (P < .05). No significant differences between the treatment and control sites were present at any other endpoints. Results of this study show that, although autologous bone marrow lacks heterotopic osteogenic potentials in this avian model, it could still function as a useful adjunct to routine bone grafting techniques because of its unique capabilities to promote early angiogenesis. PMID:22458179

  8. Potential Effects of Phytoestrogen Genistein in Modulating Acute Methotrexate Chemotherapy-Induced Osteoclastogenesis and Bone Damage in Rats

    PubMed Central

    King, Tristan J.; Shandala, Tetyana; Lee, Alice M.; Foster, Bruce K.; Chen, Ke-Ming; Howe, Peter R.; Xian, Cory J.

    2015-01-01

    Chemotherapy-induced bone damage is a frequent side effect which causes diminished bone mineral density and fracture in childhood cancer sufferers and survivors. The intensified use of anti-metabolite methotrexate (MTX) and other cytotoxic drugs has led to the need for a mechanistic understanding of chemotherapy-induced bone loss and for the development of protective treatments. Using a young rat MTX-induced bone loss model, we investigated potential bone protective effects of phytoestrogen genistein. Oral gavages of genistein (20 mg/kg) were administered daily, for seven days before, five days during, and three days after five once-daily injections (sc) of MTX (0.75 mg/kg). MTX treatment reduced body weight gain and tibial metaphyseal trabecular bone volume (p < 0.001), increased osteoclast density on the trabecular bone surface (p < 0.05), and increased the bone marrow adipocyte number in lower metaphyseal bone (p < 0.001). Genistein supplementation preserved body weight gain (p < 0.05) and inhibited ex vivo osteoclast formation of bone marrow cells from MTX-treated rats (p < 0.001). However, MTX-induced changes in bone volume, trabecular architecture, metaphyseal mRNA expression of pro-osteoclastogenic cytokines, and marrow adiposity were not significantly affected by the co-administration of genistein. This study suggests that genistein may suppress MTX-induced osteoclastogenesis; however, further studies are required to examine its potential in protecting against MTX chemotherapy-induced bone damage. PMID:26258775

  9. [Biocompatibility of alpha-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites for bone reconstruction application].

    PubMed

    Lou, Yi; Pan, Zongyou; Wu, Ruikai; Xue, Enxing; Jiang, Libo; Yang, Guangyong; Zhou, Yang; Liu, Jianli; Huang, Qing; Xu, Huazi

    2012-03-01

    We examined the biocompatibility and the safety of a-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites for bone reconstruction application. The biocompatibility of the CSH/MWCNT composites was evaluated by the measures which taking L929 fibroblast cells cultured in the extracted liquid of the composite soaking solution and putting bone marrow stromal cells planted on the composite pellets in vitro, respectively. The cell proliferation was evaluated by MTT test and further observed using an inverted optical microscope and a scanning electric microscope. The toxicity of the composites was evaluated by acute and subacute systemic toxicity test. Long-term muscle and bone implantation in vivo tests were also conducted. L929 fibroblast cells grew well in the extracted liquid, as well as bone marrow stromal cells that could adhere on the surface of sample pellets and proliferated rapidly. MTT test showed that there were no significant differences between the experimental and control groups (P > 0.05). In vivo test manifested that the composites were no toxicity, no irritation to skin and good for bone defect reconstruction. It was proved that a-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites exhibited excellent biocompatibility for the potential application in bone tissue engineering. PMID:22712392

  10. Application of synchrotron radiation computed microtomography for quantification of bone microstructure in human and rat bones

    NASA Astrophysics Data System (ADS)

    Nogueira, Liebert Parreiras; Barroso, Regina Cély; de Almeida, André Pereira; Braz, Delson; de Almeida, Carlos Eduardo; de Andrade, Cherley Borba; Tromba, Giuliana

    2012-05-01

    This work aims to evaluate histomorphometric quantification by synchrotron radiation computed microto-mography in bones of human and rat specimens. Bones specimens are classified as normal and pathological (for human samples) and irradiated and non-irradiated samples (for rat ones). Human bones are specimens which were affected by some injury, or not. Rat bones are specimens which were irradiated, simulating radiotherapy procedures, or not. Images were obtained on SYRMEP beamline at the Elettra Synchrotron Laboratory in Trieste, Italy. The system generated 14 μm tomographic images. The quantification of bone structures were performed directly by the 3D rendered images using a home-made software. Resolution yielded was excellent what facilitate quantification of bone microstructures.

  11. Application of synchrotron radiation computed microtomography for quantification of bone microstructure in human and rat bones

    SciTech Connect

    Parreiras Nogueira, Liebert; Barroso, Regina Cely; Pereira de Almeida, Andre; Braz, Delson; Almeida, Carlos Eduardo de; Borba de Andrade, Cherley; Tromba, Giuliana

    2012-05-17

    This work aims to evaluate histomorphometric quantification by synchrotron radiation computed microto-mography in bones of human and rat specimens. Bones specimens are classified as normal and pathological (for human samples) and irradiated and non-irradiated samples (for rat ones). Human bones are specimens which were affected by some injury, or not. Rat bones are specimens which were irradiated, simulating radiotherapy procedures, or not. Images were obtained on SYRMEP beamline at the Elettra Synchrotron Laboratory in Trieste, Italy. The system generated 14 {mu}m tomographic images. The quantification of bone structures were performed directly by the 3D rendered images using a home-made software. Resolution yielded was excellent what facilitate quantification of bone microstructures.

  12. Gene delivery nanocarriers of bioactive glass with unique potential to load BMP2 plasmid DNA and to internalize into mesenchymal stem cells for osteogenesis and bone regeneration

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Hyun; Singh, Rajendra K.; Kang, Min Sil; Kim, Joong-Hyun; Kim, Hae-Won

    2016-04-01

    The recent development of bioactive glasses with nanoscale morphologies has spurred their specific applications in bone regeneration, for example as drug and gene delivery carriers. Bone engineering with stem cells genetically modified with this unique class of nanocarriers thus holds great promise in this avenue. Here we report the potential of the bioactive glass nanoparticle (BGN) system for the gene delivery of mesenchymal stem cells (MSCs) targeting bone. The composition of 15% Ca-added silica, proven to be bone-bioactive, was formulated into surface aminated mesoporous nanospheres with enlarged pore sizes, to effectively load and deliver bone morphogenetic protein-2 (BMP2) plasmid DNA. The enlarged mesopores were highly effective in loading BMP2-pDNA with an efficiency as high as 3.5 wt% (pDNA w.r.t. BGN), a level more than twice than for small-sized mesopores. The BGN nanocarriers released the genetic molecules in a highly sustained manner (for as long as 2 weeks). The BMP2-pDNA/BGN complexes were effectively internalized to rat MSCs with a cell uptake level of ~73%, and the majority of cells were transfected to express the BMP2 protein. Subsequent osteogenesis of the transfected MSCs was demonstrated by the expression of bone-related genes, including bone sialoprotein, osteopontin, and osteocalcin. The MSCs transfected with BMP2-pDNA/BGN were locally delivered inside a collagen gel to the target calvarium defects. The results showed significantly improved bone regeneration, as evidenced by the micro-computed tomographic, histomorphometric and immunohistochemical analyses. This study supports the excellent capacity of the BGN system as a pDNA-delivery nanocarrier in MSCs, and the engineered system, BMP2-pDNA/BGN with MSCs, may be considered a new promising candidate to advance the therapeutic potential of stem cells through genetic modification, targeting bone defects and diseases.The recent development of bioactive glasses with nanoscale morphologies has

  13. Reduction of Dietary Acid Load as a Potential Countermeasure for Bone Loss Associated with Spaceflight

    NASA Technical Reports Server (NTRS)

    Zwart, S. R.; Watts, S. M.; Sams, C. F.; Whitson, P. A.; Smith, S. M.

    2006-01-01

    In several studies we tested the concepts that diet can alter acid-base balance and that reducing the dietary acid load has a positive effect on maintenance of bone. In study 1, (n = 11, 60-90 d bed rest), the renal acid load of the diet was estimated from its chemical composition, and was positively correlated with urinary markers of bone resorption (P less than 0.05); that is, the greater the acid load, the greater the excretion of bone resorption markers. In study 2, in males (n = 8, 30 d bed rest), an estimate of the ratio of nonvolatile acid precursors to base precursors in the diet was positively correlated (P less than 0.05) with markers of bone resorption. In study 3, for 28 d subjects received either a placebo (n = 6) or an essential amino acid supplement (n = 7) that included methionine, a known acid precursor. During bed rest (28 d), urinary calcium was greater than baseline levels in the supplemented group but not the control group (P less than 0.05), and in the supplemented group, urinary pH decreased (P less than 0.05). In study 4, less bone resorption occurred in space crew members who received potassium citrate (n = 6) during spaceflight of 4-6 months than in crew members who received placebo or were not in the study (n = 8) (P less than 0.05). Reducing acid load has the potential to mitigate increased bone resorption during spaceflight, and may serve as a bone loss countermeasure.

  14. Icariin: does it have an osteoinductive potential for bone tissue engineering?

    PubMed

    Zhang, Xin; Liu, Tie; Huang, Yuanliang; Wismeijer, Daniel; Liu, Yuelian

    2014-04-01

    Traditional Chinese medicines have been recommended for bone regeneration and repair for thousands of years. Currently, the Herba Epimedii and its multi-component formulation are the attractive native herbs for the treatment of osteoporosis. Icariin, a typical flavonol glycoside, is considered to be the main active ingredient of the Herba Epimedii from which icariin has been successfully extracted. Most interestingly, it has been reported that icariin can be delivered locally by biomaterials and that it has an osteoinductive potential for bone tissue engineering. This review focuses on the performance of icariin in bone tissue engineering and on blending the information from icariin with the current knowledge relevant to molecular mechanisms and signal pathways. The osteoinductive potential of icariin could be attributed to its multiple functions in the musculoskeletal system which is involved in the regulation of multiple signaling pathways in anti-osteoporosis, osteogenesis, anti-osteoclastogenesis, chondrogenesis, angiogenesis, and anti-inflammation. The osteoinductive potential and the low price of icariin make it a very attractive candidate as a substitute of osteoinductive protein-bone morphogenetic proteins (BMPs), or as a promoter for enhancing the therapeutic effects of BMPs. However, the effectiveness of the local delivery of icariin needs to be investigated further. PMID:23824956

  15. Gene delivery nanocarriers of bioactive glass with unique potential to load BMP2 plasmid DNA and to internalize into mesenchymal stem cells for osteogenesis and bone regeneration.

    PubMed

    Kim, Tae-Hyun; Singh, Rajendra K; Kang, Min Sil; Kim, Joong-Hyun; Kim, Hae-Won

    2016-04-14

    The recent development of bioactive glasses with nanoscale morphologies has spurred their specific applications in bone regeneration, for example as drug and gene delivery carriers. Bone engineering with stem cells genetically modified with this unique class of nanocarriers thus holds great promise in this avenue. Here we report the potential of the bioactive glass nanoparticle (BGN) system for the gene delivery of mesenchymal stem cells (MSCs) targeting bone. The composition of 15% Ca-added silica, proven to be bone-bioactive, was formulated into surface aminated mesoporous nanospheres with enlarged pore sizes, to effectively load and deliver bone morphogenetic protein-2 (BMP2) plasmid DNA. The enlarged mesopores were highly effective in loading BMP2-pDNA with an efficiency as high as 3.5 wt% (pDNA w.r.t. BGN), a level more than twice than for small-sized mesopores. The BGN nanocarriers released the genetic molecules in a highly sustained manner (for as long as 2 weeks). The BMP2-pDNA/BGN complexes were effectively internalized to rat MSCs with a cell uptake level of ∼73%, and the majority of cells were transfected to express the BMP2 protein. Subsequent osteogenesis of the transfected MSCs was demonstrated by the expression of bone-related genes, including bone sialoprotein, osteopontin, and osteocalcin. The MSCs transfected with BMP2-pDNA/BGN were locally delivered inside a collagen gel to the target calvarium defects. The results showed significantly improved bone regeneration, as evidenced by the micro-computed tomographic, histomorphometric and immunohistochemical analyses. This study supports the excellent capacity of the BGN system as a pDNA-delivery nanocarrier in MSCs, and the engineered system, BMP2-pDNA/BGN with MSCs, may be considered a new promising candidate to advance the therapeutic potential of stem cells through genetic modification, targeting bone defects and diseases. PMID:27035682

  16. 227Th-EDTMP: a potential therapeutic agent for bone metastasis.

    PubMed

    Washiyama, Kohshin; Amano, Ryohei; Sasaki, Jun; Kinuya, Seigo; Tonami, Norihisa; Shiokawa, Yoshinobu; Mitsugashira, Toshiaki

    2004-10-01

    The biodistribution of 227Th-EDTMP and retention of its daughter nuclide 223Ra were examined. 227Th-EDTMP was found to show high uptake and long-term retention in bone. The clearance of 227Th-EDTMP from blood and soft tissues was rapid and the femur-to-tissue uptake ratios reached more than 100 within 30 min for all tissues except the kidney. Seven and 14 days after injection of 227Th-EDTMP, the retention index of 223Ra in bone showed high values, and the differences between these time points were not significant. Therefore, 227Th-EDTMP is a potential radiotherapeutic agent for bone metastasis. PMID:15464392

  17. Bone Reconstruction following Application of Bone Matrix Gelatin to Alveolar Defects: A Randomized Clinical Trial

    PubMed Central

    Bayat, M.; Momen Heravi, F.; Mahmoudi, M.; Bahrami, N.

    2015-01-01

    Background: Conventional dentoalveolar osseous reconstruction often involves the use of graft materials with or without barrier membranes. Objective: To evaluate the efficacy of bone induction by bone matrix gelatin (BMG), delivered on an absorbable collagen sponge (ACS), compared to a placebo (ACS alone) in human alveolar socket defects. Methods: 20 alveolar sockets from 10 healthy adults were studied. In all cases, both the mandibular premolar area and the contralateral premolar area (as the control site) were involved. In each of the 10 patients, the extraction sites were filled randomly with BMG and ACS. The repair response was examined on day 90. Qualitative histological and quantitative histometric analysis, including the percentage of new-formed bone fill and density were done. Results: Assessment of the alveolar bone indicated that patients treated with BMG had significantly (p<0.05) better bone quality and quantity compared to the controls. In addition, bone density and histology revealed no differences between the newly induced and native bone. Conclusion: The data from this single-blind clinical trial demonstrated that the novel combination of BMG had a striking effect on de novo osseous formation for the bone regeneration. PMID:26576263

  18. Verapamil potentiation of melphalan cytotoxicity and cellular uptake in murine fibrosarcoma and bone marrow.

    PubMed Central

    Robinson, B. A.; Clutterbuck, R. D.; Millar, J. L.; McElwain, T. J.

    1985-01-01

    Growth delay by melphalan of two fibrosarcomas in CBA mice was prolonged by intraperitoneal (i.p.) verapamil, 10 mg kg-1. Verapamil also increased the area under the blood concentration time curve and the gastrointestinal toxicity of melphalan. Verapamil promoted melphalan cytotoxicity to murine bone marrow both in vivo, by CFU-S assay, and in vitro, by CFU-GM assay. In 1 microgram ml-1 [14C]-melphalan, verapamil (10 micrograms ml-1) increased by 1.5 times the [14C]-melphalan accumulation by murine bone marrow, reversibly and independently of external calcium. Efflux of [14C]-melphalan from murine bone marrow was retarded by verapamil. Verapamil increased [14C]-melphalan uptake by disaggregated fibrosarcoma cells but had no effect on melphalan accumulation and cytotoxicity in human bone marrow. Although verapamil affected melphalan pharmacokinetics, enhancement of cellular melphalan uptake by verapamil in murine fibrosarcoma and bone marrow appeared to account for much of the increase in melphalan cytotoxicity. The lack of potentiation of melphalan by verapamil in human marrow suggests differences in melphalan transport or in verapamil membrane interactions in mouse and man. PMID:4074636

  19. BMI and BMD: The Potential Interplay between Obesity and Bone Fragility

    PubMed Central

    Palermo, Andrea; Tuccinardi, Dario; Defeudis, Giuseppe; Watanabe, Mikiko; D’Onofrio, Luca; Lauria Pantano, Angelo; Napoli, Nicola; Pozzilli, Paolo; Manfrini, Silvia

    2016-01-01

    Recent evidence demonstrating an increased fracture risk among obese individuals suggests that adipose tissue may negatively impact bone health, challenging the traditional paradigm of fat mass playing a protective role towards bone health. White adipose tissue, far from being a mere energy depot, is a dynamic tissue actively implicated in metabolic reactions, and in fact secretes several hormones called adipokines and inflammatory factors that may in turn promote bone resorption. More specifically, Visceral Adipose Tissue (VAT) may potentially prove detrimental. It is widely acknowledged that obesity is positively associated to many chronic disorders such as metabolic syndrome, dyslipidemia and type 2 diabetes, conditions that could themselves affect bone health. Although aging is largely known to decrease bone strength, little is yet known on the mechanisms via which obesity and its comorbidities may contribute to such damage. Given the exponentially growing obesity rate in recent years and the increased life expectancy of western countries it appears of utmost importance to timely focus on this topic. PMID:27240395

  20. Aerospace Power Technology for Potential Terrestrial Applications

    NASA Technical Reports Server (NTRS)

    Lyons, Valerie J.

    2012-01-01

    Aerospace technology that is being developed for space and aeronautical applications has great potential for providing technical advances for terrestrial power systems. Some recent accomplishments arising from activities being pursued at the National Aeronautics and Space Administration (NASA) Centers is described in this paper. Possible terrestrial applications of the new aerospace technology are also discussed.

  1. Potential application of ocular and cervical vestibular-evoked myogenic potentials in Meniere's disease: a review.

    PubMed

    Young, Yi-Ho

    2013-02-01

    By stimulating the ear with air-conducted sound or bone-conducted vibration stimuli, vestibular-evoked myogenic potential (VEMP) can be recorded on the contracted neck muscles, termed cervical VEMP (cVEMP), and on the extraocular muscles, termed ocular VEMP (oVEMP). These two electrophysiological tests expand the test battery for clinicians to explore the dynamic otolithic function, adding a potential usefulness to the sacculocollic reflex and vestibulo-ocular reflex, respectively. The inner ear test battery, including audiometry, and cVEMP, oVEMP and caloric tests, is designed for complete evaluation of the inner ear function, namely, the cochlea, saccule, utricle, and semicircular canals, respectively. Using this test battery to study the localization and prevalence of hydrops formation reveals that the declining function in the cochlea, saccule, utricle, and semicircular canals mimics the declining sequence of hydrops formation in temporal bone studies. This study reviewed the physiological results in Meniere's patients via the inner ear test battery, especially the potential application of the oVEMP and cVEMP tests, to correlate with the histopathological findings of Meniere's disease. PMID:23070719

  2. Dietary Strontium Increases Bone Mineral Density in Intact Zebrafish (Danio rerio): A Potential Model System for Bone Research

    PubMed Central

    Padgett-Vasquez, Steve; Garris, Heath W.; Nagy, Tim R.; D'Abramo, Louis R.; Watts, Stephen A.

    2010-01-01

    Abstract Zebrafish (Danio rerio) skeletal bone possesses properties similar to human bone, which suggests that they may be used as a model to study mineralization characteristics of the human Haversian system, as well as human bone diseases. One prerequisite for the use of zebrafish as an alternative osteoporotic bone model is to determine whether their bone displays functional plasticity similar to that observed in other bone models. Strontium citrate was supplemented into a laboratory-prepared diet (45% crude protein) to produce dietary strontium levels of 0%, 0.63%, 1.26%, 1.89%, and 2.43% and fed ad libitum twice daily for 12 weeks to 28-day-old intact zebrafish. Length was determined at 4-week intervals, and both weight and length were recorded at 12 weeks. At 12 weeks, seven zebrafish from each dietary level were analyzed for total bone mineral density by microcomputed tomography. Dietary strontium citrate supplementation significantly (p < 0.05) increased zebrafish whole-body and spinal column bone mineral density. In addition, trace amounts of strontium were incorporated into the scale matrix in those zebrafish that consumed strontium-supplemented diets. These findings suggest that zebrafish bone displays plasticity similar to that reported for other bone models (i.e., rat, mouse, and monkey) that received supplements of strontium compounds and zebrafish should be viewed as an increasingly valuable bone model. PMID:20874492

  3. Dietary strontium increases bone mineral density in intact zebrafish (Danio rerio): a potential model system for bone research.

    PubMed

    Siccardi, Anthony J; Padgett-Vasquez, Steve; Garris, Heath W; Nagy, Tim R; D'Abramo, Louis R; Watts, Stephen A

    2010-09-01

    Zebrafish (Danio rerio) skeletal bone possesses properties similar to human bone, which suggests that they may be used as a model to study mineralization characteristics of the human Haversian system, as well as human bone diseases. One prerequisite for the use of zebrafish as an alternative osteoporotic bone model is to determine whether their bone displays functional plasticity similar to that observed in other bone models. Strontium citrate was supplemented into a laboratory-prepared diet (45% crude protein) to produce dietary strontium levels of 0%, 0.63%, 1.26%, 1.89%, and 2.43% and fed ad libitum twice daily for 12 weeks to 28-day-old intact zebrafish. Length was determined at 4-week intervals, and both weight and length were recorded at 12 weeks. At 12 weeks, seven zebrafish from each dietary level were analyzed for total bone mineral density by microcomputed tomography. Dietary strontium citrate supplementation significantly (p < 0.05) increased zebrafish whole-body and spinal column bone mineral density. In addition, trace amounts of strontium were incorporated into the scale matrix in those zebrafish that consumed strontium-supplemented diets. These findings suggest that zebrafish bone displays plasticity similar to that reported for other bone models (i.e., rat, mouse, and monkey) that received supplements of strontium compounds and zebrafish should be viewed as an increasingly valuable bone model. PMID:20874492

  4. Clinical-scale expansion of a mixed population of bone-marrow-derived stem and progenitor cells for potential use in bone-tissue regeneration.

    PubMed

    Dennis, James E; Esterly, Kelly; Awadallah, Amad; Parrish, Christopher R; Poynter, Gregory M; Goltry, Kristin L

    2007-10-01

    Preclinical and clinical studies have demonstrated the ability of bone marrow derived stem and progenitor cells to regenerate many tissues, including bone. Methods to expand or enrich progenitors from bone marrow are common; however, these methods include many steps not amenable to clinical use. A closed automated cell production culture system was developed for clinical-scale ex vivo production of bone marrow-derived stem and progenitor cells for hematopoietic reconstitution. The current study tested the ability of this bioreactor system to produce progenitor cells, termed tissue repair cells (TRC), possessing osteogenic potential. Three TRC formulations were evaluated: (a) cells cultured without exogenous cytokines (TRC); (b) cells cultured with exogenous cytokines (TRC-C); and (c) an adherent subset of TRC-C (TRC-C(Ad)). Starting human bone marrow mononuclear cells (BM MNC) and TRC products were characterized for the expression of cell surface markers, in vitro colony forming ability, and in vivo osteogenic potential. Results showed significant expansion of mesenchymal progenitors (CD90+, CD105+, and CD166+) in each TRC formulation. In vivo bone formation, measured by histology, was highest in the TRC group, followed by TRC-C(Ad) and TRC-C. The TRC product outperformed starting BM MNC and had equivalent bone forming potential to purified MSCs at the same cell dose. Post hoc analysis revealed that the presence of CD90+, CD105+, and CD166+ correlated strongly with in vivo bone formation scores (r(2) > .95). These results demonstrate that this bioreactor system can be used to generate, in a single step, a population of progenitor cells with potent osteogenic potential. Disclosure of potential conflicts of interest is found at the end of this article. PMID:17585167

  5. Mechanical properties and osteogenic potential of hydroxyapatite-PLGA-collagen biomaterial for bone regeneration.

    PubMed

    Bhuiyan, Didarul B; Middleton, John C; Tannenbaum, Rina; Wick, Timothy M

    2016-08-01

    A bone graft is a complicated structure that provides mechanical support and biological signals that regulate bone growth, reconstruction, and repair. A single-component material is inadequate to provide a suitable combination of structural support and biological stimuli to promote bone regeneration. Multicomponent composite biomaterials lack adequate bonding among the components to prevent phase separation after implantation. We have previously developed a novel multistep polymerization and fabrication process to construct a nano-hydroxyapatite-poly(D,L-lactide-co-glycolide)-collagen biomaterial (abbreviated nHAP-PLGA-collagen) with the components covalently bonded to each other. In the present study, the mechanical properties and osteogenic potential of nHAP-PLGA-collagen are characterized to assess the material's suitability to support bone regeneration. nHAP-PLGA-collagen films exhibit tensile strength very close to that of human cancellous bone. Human mesenchymal stem cells (hMSCs) are viable on 2D nHAP-PLGA-collagen films with a sevenfold increase in cell population after 7 days of culture. Over 5 weeks of culture, hMSCs deposit matrix and mineral consistent with osteogenic differentiation and bone formation. As a result of matrix deposition, nHAP-PLGA-collagen films cultured with hMSCs exhibit 48% higher tensile strength and fivefold higher moduli compared to nHAP-PLGA-collagen films without cells. More interestingly, secretion of matrix and minerals by differentiated hMSCs cultured on the nHAP-PLGA-collagen films for 5 weeks mitigates the loss of mechanical strength that accompanies PLGA hydrolysis. PMID:27120980

  6. Nanohydroxyapatite shape and its potential role in bone formation: an analytical study

    PubMed Central

    Kalia, Priya; Vizcay-Barrena, Gema; Fan, Jian Ping; Warley, Alice; Di Silvio, Lucy; Huang, Jie

    2014-01-01

    Bone cells (osteoblasts) produce a collagen-rich matrix called osteoid, which is mineralized extracellularly by nanosized calcium phosphate (CaP). Synthetically produced CaP nanoparticles (NPs) have great potential for clinical application. However few studies have compared the effect of CaP NPs with different properties, such as shape and aspect ratio, on the survival and behaviour of active bone-producing cells, such as primary human osteoblasts (HOBs). This study aimed to investigate the biocompatibility and ultrastructural effects of two differently shaped hydroxyapatite [Ca10(PO4)6(OH)2] nanoparticles (HA NPs), round- (aspect ratio 2.12, AR2) and rice-shaped (aspect ratio 3.79, AR4). The ultrastructural response and initial extracellular matrix (ECM) formation of HOBs to HA NPs were observed, as well as matrix vesicle release. A transmission electron microscopy (TEM)-based X-ray microanalytical technique was used to measure cytoplasmic ion levels, including calcium (Ca), phosphorus (P), sodium (Na) and potassium (K). K/Na ratios were used as a measure of cell viability. Following HA NP stimulation, all measured cytoplasmic ion levels increased. AR2 NPs had a greater osteogenic effect on osteoblasts compared with AR4 NPs, including alkaline phosphatase activity and matrix vesicle release. However, they produced only a moderate increase in intracellular Ca and P levels compared with AR4. This suggests that particular Ca and P concentrations may be required for, or indicative of, optimal osteoblast activity. Cell viability, as measured by Na and K microanalysis, was best maintained in AR2. Initial formation of osteoblast ECM was altered in the presence of either HA NP, and immuno-TEM identified fibronectin and matrilin-3 as two ECM proteins affected. Matrilin-3 is here described for the first time as being expressed by cultured osteoblasts. In summary, this novel and in-depth study has demonstrated that HA NP shape can influence a range of different parameters

  7. A case for bone canaliculi as the anatomical site of strain generated potentials

    NASA Technical Reports Server (NTRS)

    Cowin, S. C.; Weinbaum, S.; Zeng, Y.

    1995-01-01

    We address the question of determining the anatomical site that is the source of the experimentally observed strain generated potentials (SGPs) in bone tissue. There are two candidates for the anatomical site that is the SGP source, the collagen-hydroxyapatite porosity and the larger size lacunar-canalicular porosity. In the past it has been argued, on the basis of experimental data and a reasonable model, that the site of the SGPs in bone is the collagen-hydroxyapatite porosity. The theoretically predicted pore radius necessary for the SGPs to reside in this porosity is 16 nm, which is somewhat larger than the pore radii estimated from gas adsorption data where the preponderance of the pores were estimated to be in the range 5-12.5 nm. However, this pore size is significantly larger than the 2 nm size of the small tracer, microperoxidase, which appears to be excluded from the mineralized matrix. In this work a similar model, but one in which the effects of fluid dynamic drag of the cell surface matrix in the bone canaliculi are included, is used to show that it is possible for the generation of SGPs to be associated with the larger size lacunar-canalicular porosity when the hydraulic drag and electrokinetic contribution of the bone fluid passage through the cell coat (glycocalyx) is considered. The consistency of the SGP data with this model is demonstrated. A general boundary condition is introduced to allow for current leakage at the bone surface. The results suggest that the current leakage is small for the in vitro studies in which the strain generated potentials have been measured.

  8. A new bone-ligament-bone autograft from the plantar plates of the toes and its potential use in scapholunate reconstruction: an anatomical study.

    PubMed

    Müller, Miriam; Reik, Milena; Sauerbier, Michael; Germann, Günter

    2008-10-01

    The study was performed to investigate a new bone-ligament-bone autograft from the plantar plate of the toes. The anatomic properties of the plantar ligaments and the technical feasibility to harvest a bone-ligament-bone graft were examined to evaluate the potential use of this graft for a suitable reconstruction of the scapholunate (SL) interosseous ligament. The plantar plate of the metatarsophalangeal joints of the second to fifth toe and the proximal interphalangeal joints of the second to fourth toe were examined in 20 cadaver feet (15 fresh and 5 embalmed cadavers) and measurements such as length, thickness, and width were taken. The average length of the plantar ligaments of the proximal interphalangeal joint was 0.63 cm (D3) and 0.62 cm (D4). The length of the plantar plates of the proximal interphalangeal joint of the third and fourth toe was found to be similar to that of the SL ligament. In addition to the measurements, a bone-ligament-bone autograft of the plantar plates of the metatarsophalangeal joint was designed as an SL-ligament substitute and successfully transplanted into cadaveric wrists. This new autograft is intercalated between the scaphoid and lunate and, contrary to all previous methods, not simply superimposed upon them. Length of the plantar plates was considered by the authors as the main criteria for selection of the new bone-ligament-bone graft. The plantar plate of the proximal interphalangeal joint of the third and fourth toe showed a similar length compared with the SL ligament. Therefore, it can be concluded from the data that this bone-ligament-bone graft can be a suitable replacement for the SL ligament. PMID:18812722

  9. Regeneration of cartilage and bone by defined subsets of mesenchymal stromal cells--potential and pitfalls.

    PubMed

    Aicher, Wilhelm K; Bühring, Hans-Jörg; Hart, Melanie; Rolauffs, Bernd; Badke, Andreas; Klein, Gerd

    2011-04-30

    Mesenchymal stromal cells, also referred to as mesenchymal stem cells, can be obtained from various tissues. Today the main source for isolation of mesenchymal stromal cells in mammals is the bone marrow. Mesenchymal stromal cells play an important role in tissue formation and organogenesis during embryonic development. Moreover, they provide the cellular and humoral basis for many processes of tissue regeneration and wound healing in infancy, adolescence and adulthood as well. There is increasing evidence that mesenchymal stromal cells from bone marrow and other sources including term placenta or adipose tissue are not a homogenous cell population. Only a restricted number of appropriate stem cells markers have been explored so far. But routine preparations of mesenchymal stromal cells contain phenotypically and functionally distinct subsets of stromal cells. Knowledge on the phenotypical characteristics and the functional consequences of such subsets will not only extend our understanding of stem cell biology, but might allow to develop improved regimen for regenerative medicine and wound healing and novel protocols for tissue engineering as well. In this review we will discuss novel strategies for regenerative medicine by specific selection or separation of subsets of mesenchymal stromal cells in the context of osteogenesis and bone regeneration. Mesenchymal stromal cells, which express the specific cell adhesion molecule CD146, also known as MCAM or MUC18, are prone for bone repair. Other cell surface proteins may allow the selection of chondrogenic, myogenic, adipogenic or other pre-determined subsets of mesenchymal stromal cells for improved regenerative applications as well. PMID:21184789

  10. Towards application of one- and two-dimensional nanomaterials for reinforcement of polymeric nanocomposite bone grafts

    NASA Astrophysics Data System (ADS)

    Farrshid, Behzad

    One- and two-dimensional (1-D and 2-D) nanomaterials possess extraordinary physiochemical properties such as large surface area, excellent mechanical properties, high surface energy and good dispersivity in organic and biological solvents, therefore, they have been extensively used as reinforcing agents to improve the mechanical properties of polymeric scaffolds for bone tissue engineering applications. Carbon nanomaterials such as carbon nanotubes and graphene have been used as reinforcing agents for biodegradable polymeric scaffolds and composites, however, their short- and long-term in vitro cytotoxicity and in vivo biocompatibility is an area of extensive debate. In this study, we have systematically investigated the effects of addition of low concentrations (0.01-0.2 wt. %) of 1-D and 2-D carbon nanomaterials (graphene oxide nanoplatelets, graphene oxide nanoribbons and carbon nanotubes) and inorganic nanomaterials (boron nitride nanotubes, boron nitride nanoplatelers, tungsten disulfide nanotubes and molybdenum disulfide nanoplatelets) on the mechanical properties, cytocompatibility, and bioactivity of poly(propylene fumarate) (PPF) nanocomposites towards their potential applications as porous and nonporous implants for bone tissue engineering. Addition of nanomaterials in the PPF matrix improved the compressive and flexural mechanical properties of non-porous crosslinked PPF nanocomposites and porous PPF scaffolds. Our results suggest that in addition to high surface roughness and surface area of the nanomaterials, the presence of functional groups on the surface of nanomaterials leads to an increased nanomaterial-polymer interaction and a uniform dispersion of nanomaterials in polymer matrix which may be the key factors responsible for an improved mechanical reinforcement. The in vitro studies showed an excellent cytocompatibility for both carbon and inorganic nanomaterial reinforced PPF nanocomposites and scaffolds. Protein adsorption studies and in vitro

  11. Low-intensity pulsed ultrasound therapy: a potential strategy to stimulate tendon-bone junction healing.

    PubMed

    Ying, Zhi-min; Lin, Tiao; Yan, Shi-gui

    2012-12-01

    Incorporation of a tendon graft within the bone tunnel represents a challenging clinical problem. Successful anterior cruciate ligament (ACL) reconstruction requires solid healing of the tendon graft in the bone tunnel. Enhancement of graft healing to bone is important to facilitate early aggressive rehabilitation and a rapid return to pre-injury activity levels. No convenient, effective or inexpensive procedures exist to enhance tendon-bone (T-B) healing after surgery. Low-intensity pulsed ultrasound (LIPUS) improves local blood perfusion and angiogenesis, stimulates cartilage maturation, enhances differentiation and proliferation of osteoblasts, and motivates osteogenic differentiation of mesenchymal stem cells (MSCs), and therefore, appears to be a potential non-invasive tool for T-B healing in early stage of rehabilitation of ACL reconstruction. It is conceivable that LIPUS could be used to stimulate T-B tunnel healing in the home, with the aim of accelerating rehabilitation and an earlier return to normal activities in the near future. The purpose of this review is to demonstrate how LIPUS stimulates T-B healing at the cellular and molecular levels, describe studies in animal models, and provide a future direction for research. PMID:23225850

  12. Fabrication of polylactide nanocomposite scaffolds for bone tissue engineering applications

    SciTech Connect

    Mkhabela, Vuyiswa J.; Ray, Suprakas Sinha

    2015-05-22

    Highly porous three-dimensional polylactide (PLA) scaffolds were obtained from PLA incorporated with different amounts of chitosan-modified montmorillonite (CS-MMT), through solvent casting and particulate leaching method. The processed scaffolds were tested in vitro for their possible application in bone tissue engineering. Scaffolds were characterized by Focused Ion Beam Scanning Electron Microscopy (FIB SEM), Fourier Transform Infra-Red (FTIR), and X-Ray Diffraction (XRD) to study their structure and intermolecular interactions. Bioresorbability tests in simulated body fluid (pH 7.4) were conducted to assess the response of the scaffolds in a simulated physiological condition. The FIB SEM images of the scaffolds showed a porous architecture with gradual change in morphology with increasing CS-MMT concentration. FTIR analysis revealed the presence of both PLA and CS-MMT particles on the surface of the scaffolds. XRD showed that the crystalline unit cell type was the same for all the scaffolds, and crystallinity decreased with an increase in CS-MMT concentration. The scaffolds were found to be bioresorbable, with rapid bioresorbability on the scaffolds with a high CS-MMT concentration.

  13. Fabrication of polylactide nanocomposite scaffolds for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Mkhabela, Vuyiswa J.; Ray, Suprakas Sinha

    2015-05-01

    Highly porous three-dimensional polylactide (PLA) scaffolds were obtained from PLA incorporated with different amounts of chitosan-modified montmorillonite (CS-MMT), through solvent casting and particulate leaching method. The processed scaffolds were tested in vitro for their possible application in bone tissue engineering. Scaffolds were characterized by Focused Ion Beam Scanning Electron Microscopy (FIB SEM), Fourier Transform Infra-Red (FTIR), and X-Ray Diffraction (XRD) to study their structure and intermolecular interactions. Bioresorbability tests in simulated body fluid (pH 7.4) were conducted to assess the response of the scaffolds in a simulated physiological condition. The FIB SEM images of the scaffolds showed a porous architecture with gradual change in morphology with increasing CS-MMT concentration. FTIR analysis revealed the presence of both PLA and CS-MMT particles on the surface of the scaffolds. XRD showed that the crystalline unit cell type was the same for all the scaffolds, and crystallinity decreased with an increase in CS-MMT concentration. The scaffolds were found to be bioresorbable, with rapid bioresorbability on the scaffolds with a high CS-MMT concentration.

  14. Magnetic targeting of mechanosensors in bone cells for tissue engineering applications.

    PubMed

    Hughes, Steven; Dobson, Jon; El Haj, Alicia J

    2007-01-01

    Mechanical signalling plays a pivotal role in maintaining bone cell function and remodelling of the skeleton. Our previous work has highlighted the potential role of mechano-induction in tissue engineering applications. In particular, we have highlighted the potential for using magnetic particle techniques for tissue engineering applications. Previous studies have shown that manipulation of integrin attached magnetic particles leads to changes in intracellular calcium signalling within osteoblasts. However, due to the phenomenon of particle internalisation, previous studies have typically focused on short-term stimulation experiments performed within 1-2 h of particle attachment. For tissue engineering applications, bone tissue growth occurs over a period of 3-5 weeks. To date, no study has investigated the cellular responses elicited from osteoblasts over time following stimulation with internalised magnetic particles. Here, we demonstrate the long-term biocompatibility of 4.5 microm RGD-coated particles with osteoblasts up to 21 days in culture, and detail a time course of responses elicited from osteoblasts following mechanical stimulation with integrin attached magnetic particles (<2h post attachment) and internalised particles (>48h post attachment). Mechanical manipulation of both integrin attached and internalised particles were found to induce intracellular calcium signalling. It is concluded that magnetic particles offer a tool for applying controlled mechanical forces to osteoblasts, and can be used to stimulate intracellular calcium signalling over prolonged periods of time. Magnetic particle technology presents a potentially valuable tool for tissue engineering which permits the delivery of highly localised mechano-inductive forces directly to cells. PMID:17532323

  15. High biocompatibility and improved osteogenic potential of novel Ca-P/titania composite scaffolds designed for regeneration of load-bearing segmental bone defects.

    PubMed

    Cunha, Carla; Sprio, Simone; Panseri, Silvia; Dapporto, Massimiliano; Marcacci, Maurilio; Tampieri, Anna

    2013-06-01

    Regeneration of load-bearing bone segments is still an open challenge due to the lack of biomaterials mimicking natural bone with a suitable chemicophysical and mechanical performance. This study proposes ceramic bone scaffolds made of β-tricalcium phosphate (β-TCP) and titania (TiO2 ), developed from hydroxyapatite (HA) and TiO2 starting nanopowders, which exhibit high and interconnected macroporosity (>70 vol %). The scaffold composition was designed to achieve a synergistic effect of bioactivity/resorbability and mechanical properties suitable for load-bearing regenerative applications. The analysis of the morphology, structure, and mechanical strength of the scaffolds resulted in compression strength nearly twice that of commercially available HA bone grafts with similar structure (Engipore(®)). Biological characterization was carried out for human MG-63 osteoblast-like cells proliferation, activity, attachment, and viability. β-TCP/TiO2 scaffolds show high proliferation rate, high viability, and high colonization rates. Moreover, an increased activity of the osteogenic marker alkaline phosphatase (ALP) was found. These results demonstrate that β-TCP/TiO2 scaffolds have good potential as osteogenically active load-bearing scaffolds; moreover, given the high and interconnected macroporosity as well as the resorbability properties of β-TCP, these scaffolds may enhance in vivo osteointegration and promote the formation of new organized bone, thus resulting in very promising biomimetic scaffolds for long bone regeneration. PMID:23172612

  16. CBCT-based bone quality assessment: are Hounsfield units applicable?

    PubMed Central

    Jacobs, R; Singer, S R; Mupparapu, M

    2015-01-01

    CBCT is a widely applied imaging modality in dentistry. It enables the visualization of high-contrast structures of the oral region (bone, teeth, air cavities) at a high resolution. CBCT is now commonly used for the assessment of bone quality, primarily for pre-operative implant planning. Traditionally, bone quality parameters and classifications were primarily based on bone density, which could be estimated through the use of Hounsfield units derived from multidetector CT (MDCT) data sets. However, there are crucial differences between MDCT and CBCT, which complicates the use of quantitative gray values (GVs) for the latter. From experimental as well as clinical research, it can be seen that great variability of GVs can exist on CBCT images owing to various reasons that are inherently associated with this technique (i.e. the limited field size, relatively high amount of scattered radiation and limitations of currently applied reconstruction algorithms). Although attempts have been made to correct for GV variability, it can be postulated that the quantitative use of GVs in CBCT should be generally avoided at this time. In addition, recent research and clinical findings have shifted the paradigm of bone quality from a density-based analysis to a structural evaluation of the bone. The ever-improving image quality of CBCT allows it to display trabecular bone patterns, indicating that it may be possible to apply structural analysis methods that are commonly used in micro-CT and histology. PMID:25315442

  17. Adenovirus-mediated expression of vascular endothelial growth factor-a potentiates bone morphogenetic protein9-induced osteogenic differentiation and bone formation.

    PubMed

    Pi, Chang-Jun; Liang, Kai-Lu; Ke, Zhen-Yong; Chen, Fu; Cheng, Yun; Yin, Liang-Jun; Deng, Zhong-Liang; He, Bai-Cheng; Chen, Liang

    2016-08-01

    Mesenchymal stem cells (MSCs) are suitable seed cells for bone tissue engineering because they can self-renew and undergo differentiation into osteogenic, adipogenic, chondrogenic, or myogenic lineages. Vascular endothelial growth factor-a (VEGF-a), an angiogenic factor, is also involved in osteogenesis and bone repair. However, the effects of VEGF-a on osteogenic MSCs differentiation remain unknown. It was previously reported that bone morphogenetic protein9 (BMP9) is one of the most important osteogenic BMPs. Here, we investigated the effects of VEGF-a on BMP9-induced osteogenesis with mouse embryo fibroblasts (MEFs). We found that endogenous VEGF-a expression was undetectable in MSCs. Adenovirus-mediated expression of VEGF-a in MEFs potentiated BMP9-induced early and late osteogenic markers, including alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). In stem cell implantation assays, VEGF-a augmented BMP9-induced ectopic bone formation. VEGF-a in combination with BMP9 effectively increased the bone volume and osteogenic activity. However, the synergistic effect was efficiently abolished by the phosphoinositide 3-kinase (PI3K)/AKT inhibitor LY294002. These results demonstrated that BMP9 may crosstalk with VEGF-a through the PI3K/AKT signaling pathway to induce osteogenic differentiation in MEFs. Thus, our findings demonstrate the effects of VEGF-a on BMP9-induced bone formation and provide a new potential strategy for treating nonunion fractures, large segmental bony defects, and/or osteoporotic fractures. PMID:27003241

  18. Hydroxyapatite-hybridized chitosan/chitin whisker bionanocomposite fibers for bone tissue engineering applications.

    PubMed

    Pangon, Autchara; Saesoo, Somsak; Saengkrit, Nattika; Ruktanonchai, Uracha; Intasanta, Varol

    2016-06-25

    Biomimetic nanofibrous scaffolds derived from natural biopolymers for bone tissue engineering applications require good mechanical and biological performances including biomineralization. The present work proposes the utility of chitin whisker (CTWK) to enhance mechanical properties of chitosan/poly(vinyl alcohol) (CS/PVA) nanofibers and to offer osteoblast cell growth with hydroxyapatite (HA) mineralization. By using diacid as a solvent, electrospun CS/PVA nanofibrous membranes containing CTWK can be easily obtained. The dimension stability of nanofibrous CS/PVA/CTWK bionanocomposite is further controlled by exposing to glutaraldehyde vapor. The nanofibrous membranes obtained allow mineralization of HA in concentrated simulated body fluid resulting in an improvement of Young's modulus and tensile strength. The CTWK combined with HA in bionanocomposite is a key to promote osteoblast cell adhesion and proliferation. The present work, for the first time, demonstrates the use of CTWKs for bionanocomposite fibers of chitosan and its hydroxyapatite biomineralization with the function in osteoblast cell culture. These hydroxyapatite-hybridized CS/PVA/CTWK bionanocomposite fibers (CS/PVA/CTWK-HA) offer a great potential for bone tissue engineering applications. PMID:27083834

  19. Clinical significance of interleukin (IL)-6 in cancer metastasis to bone: potential of anti-IL-6 therapies

    PubMed Central

    Tawara, Ken; Oxford, Julia T; Jorcyk, Cheryl L

    2011-01-01

    Metastatic events to the bone occur frequently in numerous cancer types such as breast, prostate, lung, and renal carcinomas, melanoma, neuroblastoma, and multiple myeloma. Accumulating evidence suggests that the inflammatory cytokine interleukin (IL)-6 is frequently upregulated and is implicated in the ability of cancer cells to metastasize to bone. IL-6 is able to activate various cell signaling cascades that include the STAT (signal transducer and activator of transcription) pathway, the PI3K (phosphatidylinositol-3 kinase) pathway, and the MAPK (mitogen-activated protein kinase) pathway. Activation of these pathways may explain the ability of IL-6 to mediate various aspects of normal and pathogenic bone remodeling, inflammation, cell survival, proliferation, and pro-tumorigenic effects. This review article will discuss the role of IL-6: 1) in bone metabolism, 2) in cancer metastasis to bone, 3) in cancer prognosis, and 4) as potential therapies for metastatic bone cancer. PMID:21625400

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

    PubMed

    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

  1. Long-term antibiotic delivery by chitosan-based composite coatings with bone regenerative potential

    NASA Astrophysics Data System (ADS)

    Ordikhani, F.; Simchi, A.

    2014-10-01

    Composite coatings with bone-bioactivity and drug-eluting capacity are considered as promising materials for titanium bone implants. In this work, drug-eluting chitosan-bioactive glass coatings were fabricated by a single-step electrophoretic deposition technique. Drug-loading and -releasing capacity of the composite coatings were carried out using the vancomycin antibiotic. Uniform coatings with a thickness of ∼55 μm containing 23.7 wt% bioactive glass particles and various amounts of the antibiotic (380-630 μg/cm2) were produced. The coatings were bioactive in terms of apatite-forming ability in simulated body fluid and showed favorable cell adhesion and growth. In vitro biological tests also indicated that the composite coatings had better cellular affinity than pristine chitosan coatings. The in vitro elution kinetics of the composite coating revealed an initial burst release of around 40% of the drug within the first elution step of 1 h and following by a continuous eluting over 4 weeks, revealing long-term drug-delivering potential. Antibacterial tests using survival assay against Gram-positive Staphylococcus aureus bacteria determined the effect of vancomycin release on reduction of infection risk. Almost no bacteria were survived on the coatings prepared from the EPD suspension containing ≥0.5 g/l vancomycin. The developed chitosan-based composite coatings with bone bioactivity and long-term drug-delivery ability may be potentially useful for metallic implants to reduce infection risk.

  2. Bacteriocins: Recent Trends and Potential Applications.

    PubMed

    Bali, Vandana; Panesar, Parmjit S; Bera, Manab B; Kennedy, John F

    2016-04-01

    In the modern era, there is great need for food preservation in both developing and developed countries due to increasing demand for extending shelf life and prevention of spoilage of food material. With the emergence of new pathogens and ability of micro-organisms to undergo changes, exploration of new avenues for the food preservation has gained importance. Moreover, awareness among consumers regarding harmful effects of chemical preservatives has been increased. Globally, altogether there is increasing demand by consumers for chemical-free and minimal processed food products. Potential of bacteriocin and its application in reducing the microbiological spoilages and in the preservation of food is long been recognized. Bacteriocins are normally specific to closely related species without disrupting the growth of other microbial populations. A number of applications of bacteriocin have been reported for humans, live stock, aquaculture etc. This review is focused on recent trends and applications of bacteriocins in different areas in addition to their biopreservative potential. PMID:25117970

  3. Mesoporous bioactive glasses: structure characteristics, drug/growth factor delivery and bone regeneration application

    PubMed Central

    Wu, Chengtie; Chang, Jiang

    2012-01-01

    The impact of bone diseases and trauma in the whole world has increased significantly in the past decades. Bioactive glasses are regarded as an important bone regeneration material owing to their generally excellent osteoconductivity and osteostimulativity. A new class of bioactive glass, referred to as mesoporous bioglass (MBG), was developed 7 years ago, which possess a highly ordered mesoporous channel structure and a highly specific surface area. The study of MBG for drug/growth factor delivery and bone tissue engineering has grown significantly in the past several years. In this article, we review the recent advances of MBG materials, including the preparation of different forms of MBG, composition–structure relationship, efficient drug/growth factor delivery and bone tissue engineering application. By summarizing our recent research, the interaction of MBG scaffolds with bone-forming cells, the effect of drug/growth factor delivery on proliferation and differentiation of tissue cells and the in vivo osteogenesis of MBG scaffolds are highlighted. The advantages and limitations of MBG for drug delivery and bone tissue engineering have been compared with microsize bioactive glasses and nanosize bioactive glasses. The future perspective of MBG is discussed for bone regeneration application by combining drug delivery with bone tissue engineering and investigating the in vivo osteogenesis mechanism in large animal models. PMID:23741607

  4. Application of an effective medium theory for modeling ultrasound wave propagation in healing long bones.

    PubMed

    Potsika, Vassiliki T; Grivas, Konstantinos N; Protopappas, Vasilios C; Vavva, Maria G; Raum, Kay; Rohrbach, Daniel; Polyzos, Demosthenes; Fotiadis, Dimitrios I

    2014-07-01

    Quantitative ultrasound has recently drawn significant interest in the monitoring of the bone healing process. Several research groups have studied ultrasound propagation in healing bones numerically, assuming callus to be a homogeneous and isotropic medium, thus neglecting the multiple scattering phenomena that occur due to the porous nature of callus. In this study, we model ultrasound wave propagation in healing long bones using an iterative effective medium approximation (IEMA), which has been shown to be significantly accurate for highly concentrated elastic mixtures. First, the effectiveness of IEMA in bone characterization is examined: (a) by comparing the theoretical phase velocities with experimental measurements in cancellous bone mimicking phantoms, and (b) by simulating wave propagation in complex healing bone geometries by using IEMA. The original material properties of cortical bone and callus were derived using serial scanning acoustic microscopy (SAM) images from previous animal studies. Guided wave analysis is performed for different healing stages and the results clearly indicate that IEMA predictions could provide supplementary information for bone assessment during the healing process. This methodology could potentially be applied in numerical studies dealing with wave propagation in composite media such as healing or osteoporotic bones in order to reduce the simulation time and simplify the study of complicated geometries with a significant porous nature. PMID:24091149

  5. From Wolff's law to the Utah paradigm: insights about bone physiology and its clinical applications.

    PubMed

    Frost, H M

    2001-04-01

    Efforts to understand our anatomy and physiology can involve four often overlapping phases. We study what occurs, then how, then ask why, and then seek clinical applications. In that regard, in 1960 views, bone's effector cells (osteoblasts and osteoclasts) worked chiefly to maintain homeostasis under the control of nonmechanical agents, and that physiology had little to do with anatomy, biomechanics, tissue-level things, muscle, and other clinical applications. But it seems later-discovered tissue-level mechanisms and functions (including biomechanical ones, plus muscle) are the true key players in bone physiology, and homeostasis ranks below the mechanical functions. Adding that information to earlier views led to the Utah paradigm of skeletal physiology that combines varied anatomical, clinical, pathological, and basic science evidence and ideas. While it explains in a general way how strong muscles make strong bones and chronically weak muscles make weak ones, and while many anatomists know about the physiology that fact depends on, poor interdisciplinary communication left people in many other specialties unaware of it and its applications. Those applications concern 1.) healing of fractures, osteotomies, and arthrodeses; 2.) criteria that distinguish mechanically competent from incompetent bones; 3.) design criteria that should let load-bearing implants endure; 4.) how to increase bone strength during growth, and how to maintain it afterwards on earth and in microgravity situations in space; 5.) how and why healthy women only lose bone next to marrow during menopause; 6.) why normal bone functions can cause osteopenias; 7.) why whole-bone strength and bone health are different matters; 8.) why falls can cause metaphyseal and diaphyseal fractures of the radius in children, but mainly metaphyseal fractures of that bone in aged adults; 9.) which methods could best evaluate whole-bone strength, "osteopenias" and "osteoporoses"; 10.) and why most "osteoporoses

  6. Potential commercial applications of microbial surfactants.

    PubMed

    Banat, I M; Makkar, R S; Cameotra, S S

    2000-05-01

    Surfactants are surface-active compounds capable of reducing surface and interfacial tension at the interfaces between liquids, solids and gases, thereby allowing them to mix or disperse readily as emulsions in water or other liquids. The enormous market demand for surfactants is currently met by numerous synthetic, mainly petroleum-based, chemical surfactants. These compounds are usually toxic to the environment and non-biodegradable. They may bio-accumulate and their production, processes and by-products can be environmentally hazardous. Tightening environmental regulations and increasing awareness for the need to protect the ecosystem have effectively resulted in an increasing interest in biosurfactants as possible alternatives to chemical surfactants. Biosurfactants are amphiphilic compounds of microbial origin with considerable potential in commercial applications within various industries. They have advantages over their chemical counterparts in biodegradability and effectiveness at extreme temperature or pH and in having lower toxicity. Biosurfactants are beginning to acquire a status as potential performance-effective molecules in various fields. At present biosurfactants are mainly used in studies on enhanced oil recovery and hydrocarbon bioremediation. The solubilization and emulsification of toxic chemicals by biosurfactants have also been reported. Biosurfactants also have potential applications in agriculture, cosmetics, pharmaceuticals, detergents, personal care products, food processing, textile manufacturing, laundry supplies, metal treatment and processing, pulp and paper processing and paint industries. Their uses and potential commercial applications in these fields are reviewed. PMID:10855707

  7. Inactivation of the Progesterone Receptor in Mx1+ Cells Potentiates Osteogenesis in Calvaria but Not in Long Bone

    PubMed Central

    Zhong, Zhendong A.; Sun, Weihua; Chen, Haiyan; Zhang, Hongliang; Lane, Nancy E.; Yao, Wei

    2015-01-01

    The effect of progesterone on bone remains elusive. We previously reported that global progesterone receptor (PR) knockout mice displayed high bone mass phenotype, suggesting that PR influences bone growth and modeling. Recently, Mx1+ cells were characterized to be mesenchymal stem cell-like pluripotent Cells. The aim of this study was to evaluate whether the PR in Mx1+ cells regulates osteogenesis. Using the Mx1-Cre;mT/mG reporter mouse model, we found that the calvarial cells exhibited minimal background Mx1-Cre activity prior to Cre activation by IFNα treatment as compared to the bone marrow stromal cells. IFNα treatment significantly activated Mx1-Cre in the calvarial cells. When the PR gene was deleted in the Mx1-Cre;PR-flox calvarial cells in vitro, significantly higher levels of expression of osteoblast maturation marker genes (RUNX2, Osteocalcin, and Dmp1) and osteogenic potential were detected. The PR-deficient calvariae exhibited greater bone volume, especially in the males. Although Mx1-Cre activity could be induced on the bone surface in vivo, the Mx1+ cells did not differentiate into osteocytes in long bones. Bone volumes at the distal femurs and the bone turnover marker serum Osteocalcin were similar between the Mx1-Cre;PR-flox mutant mice and the corresponding wild types in both sexes. In conclusion, our data demonstrates that blocking progesterone signaling via PRs in calvarial Mx1+ cells promoted osteoblast differentiation in the calvaria. Mx1+ was expressed by heterogeneous cells in bone marrow and did not differentiate into osteocyte during long bone development in vivo. Selectively inactivating the PR gene in Mx1+ cells affected the membrane bone formation but did not affect peripheral skeletal homeostasis. PMID:26431032

  8. Biomineralization of Natural Collagenous Nanofibrous Membranes and Their Potential Use in Bone Tissue Engineering

    PubMed Central

    Yang, Mingying; Zhou, Guanshan; Castano-Izquierdo, Harold; Zhu, Ye; Mao, Chuanbin

    2015-01-01

    Small intestinal submucosa (SIS) membranes as a decellularized tissue are known to be a natural nanofibrous biomaterial mainly made of type I collagen fibers and containing some growth factors (fibroblast growth factor 2 and transforming growth factor β) desired in tissue engineering. Here we show that the SIS membranes can promote the formation of bone mineral hydroxylapatite (HAP) crystals along the collagen fibers constituting the membranes from a HAP-supersaturated solution. The resultant biomineralized HAP-SIS scaffolds were found to promote the attachment, growth and osteogenic differentiation of mesenchymal stem cells (MSCs) in both basal and osteogenic media by the evaluation of osteogenic marker formation. More importantly, the HAP-SIS scaffolds could induce the osteogenic differentiation in the basal media without osteogenic supplements due to the presence of HAP crystals in the scaffolds. Histological characterization of the MSC-seeded scaffolds showed that HAP-SIS scaffolds are biocompatible and promote the formation of new tissue in vitro. The biomineralized SIS membranes mimic some aspects of natural bone in terms of the composition and nanostructures and can find potential use in bone tissue engineering. PMID:25883539

  9. Biomineralization of Natural Collagenous Nanofibrous Membranes and Their Potential Use in Bone Tissue Engineering.

    PubMed

    Yang, Mingying; Zhou, Guanshan; Castano-Izquierdo, Harold; Zhu, Ye; Mao, Chuanbin

    2015-03-01

    Small intestinal submucosa (SIS) membranes as a decellularized tissue are known to be a natural nanofibrous biomaterial mainly made of type I collagen fibers and containing some growth factors (fibroblast growth factor 2 and transforming growth factor β) desired in tissue engineering. Here we show that the SIS membranes can promote the formation of bone mineral hydroxylapatite (HAP) crystals along the collagen fibers constituting the membranes from a HAP-supersaturated solution. The resultant biomineralized HAP-SIS scaffolds were found to promote the attachment, growth and osteogenic differentiation of mesenchymal stem cells (MSCs) in both basal and osteogenic media by the evaluation of osteogenic marker formation. More importantly, the HAP-SIS scaffolds could induce the osteogenic differentiation in the basal media without osteogenic supplements due to the presence of HAP crystals in the scaffolds. Histological characterization of the MSC-seeded scaffolds showed that HAP-SIS scaffolds are biocompatible and promote the formation of new tissue in vitro. The biomineralized SIS membranes mimic some aspects of natural bone in terms of the composition and nanostructures and can find potential use in bone tissue engineering. PMID:25883539

  10. Differential effects and glucocorticoid potentiation of bone morphogenetic protein action during rat osteoblast differentiation in vitro.

    PubMed

    Boden, S D; McCuaig, K; Hair, G; Racine, M; Titus, L; Wozney, J M; Nanes, M S

    1996-08-01

    Bone morphogenetic proteins (BMPs) induce cartilage and bone differentiation in vivo and promote osteoblast differentiation from calvarial and marrow stromal cell preparations. Functional differences between BMP-2, -4, and -6 are not well understood. Recent investigations find that these three closely related osteoinductive proteins may exert different effects in primary rat calvarial cell cultures, suggesting the possibility of unique functions in vivo. In this study, we use a fetal rat secondary calvarial cell culture system to examine the differential effects of BMP-2, -4, and -6 on early osteoblast differentiation. These cells do not spontaneously differentiate into osteoblasts, as do cells in primary calvarial cultures, but rather require exposure to a differentiation initiator such as glucocorticoid or BMP. We determined that BMP-6 is a 2- to 2.5-fold more potent inducer of osteoblast differentiation than BMP-2 or -4. BMP-6 induced the formation of more and larger bone nodules as well as increased osteocalcin secretion. The effects of all three of these BMPs were potentiated up to 10-fold by cotreatment or pretreatment with the glucocorticoid triamcinolone (Trm). The Trm effects were synergistic with those of BMP-2 or -4, suggesting that this glucocorticoid may increase the cell responsiveness to these BMPs. Finally, BMP-6 did not require either cotreatment or pretreatment with Trm to achieve greater amounts of osteoblast differentiation than seen with BMP-2 or BMP-4 treatment, suggesting that BMP-6 may act at an earlier stage of cell differentiation. PMID:8754767

  11. Osteogenesis and cytotoxicity of a new Carbon Fiber/Flax/Epoxy composite material for bone fracture plate applications.

    PubMed

    Bagheri, Zahra S; Giles, Erica; El Sawi, Ihab; Amleh, Asma; Schemitsch, Emil H; Zdero, Radovan; Bougherara, Habiba

    2015-01-01

    This study is part of an ongoing program to develop a new CF/Flax/Epoxy bone fracture plate to be used in orthopedic trauma applications. The purpose was to determine this new plate's in-vitro effects on the level of bone formation genes, as well as cell viability in comparison with a medical grade metal (i.e. stainless steel) commonly employed for fabrication of bone plates (positive control). Cytotoxicity and osteogenesis induced by wear debris of the material were assessed using Methyl Tetrazolium (MTT) assay and reverse transcription polymerase chain reaction (RT-PCR) for 3 osteogenesis specific gene markers, including bone morphogenetic proteins (BMP2), runt-related transcription factor 2 (Runx2) and Osterix. Moreover, the Flax/Epoxy and CF/Epoxy composites were examined separately for their wettability properties by water absorption and contact angle (CA) tests using the sessile drop technique. The MTT results for indirect and direct assays indicated that the CF/Flax/Epoxy composite material showed comparable cell viability with no cytotoxicity at all incubation times to that of the metal group (p≥0.05). Osteogenesis test results showed that the expression level of Runx2 marker induced by CF/Flax/Epoxy were significantly higher than those induced by metal after 48 h (p=0.57). Also, the Flax/Epoxy composite revealed a hydrophilic character (CA=68.07°±2.05°) and absorbed more water up to 17.2% compared to CF/Epoxy, which reached 1.25% due to its hydrophobic character (CA=93.22°±1.95°) (p<0.001). Therefore, the new CF/Flax/Epoxy may be a potential candidate for medical applications as a bone fracture plate, as it showed similar cell viability with no negative effect on gene expression levels responsible for bone formation compared to medical grade stainless steel. PMID:25492008

  12. Immature articular cartilage and subchondral bone covered by menisci are potentially susceptive to mechanical load

    PubMed Central

    2014-01-01

    Background The differences of mechanical and histological properties between cartilage covered by menisci and uncovered by menisci may contribute to the osteoarthritis after meniscectomy and these differences are not fully understood. The purpose of this study is to investigate potential differences in the mechanical and histological properties, and in particular the collagen architecture, of the superficial cartilage layer and subchondral bone between regions covered and uncovered by menisci using immature knee. Methods Osteochondral plugs were obtained from porcine tibial cartilage that was either covered or uncovered by menisci. Investigation of the thickness, mechanical properties, histology, and water content of the cartilage as well as micro-computed tomography analysis of the subchondral bone was performed to compare these regions. Collagen architecture was also assessed by using scanning electron microscopy. Results Compared to the cartilage uncovered by menisci, that covered by menisci was thinner and showed a higher deformity to compression loading and higher water content. In the superficial layer of cartilage in the uncovered regions, collagen fibers showed high density, whereas they showed low density in covered regions. Furthermore, subchondral bone architecture varied between the 2 regions, and showed low bone density in covered regions. Conclusions Cartilage covered by menisci differed from that uncovered in both its mechanical and histological properties, especially with regards to the density of the superficial collagen layer. These regional differences may be related to local mechanical environment in normal condition and indicate that cartilage covered by menisci is tightly guarded by menisci from extreme mechanical loading. Our results indicate that immature cartilage degeneration and subchondral microfracture may occur easily to extreme direct mechanical loading in covered region after meniscectomy. PMID:24669849

  13. Application of bone marrow mesenchymal stem cells to the treatment of osteonecrosis of the femoral head

    PubMed Central

    Wang, Cheng; Wang, Yu; Meng, Hao-Ye; Yuan, Xue-Ling; Xu, Xiao-Long; Wang, Ai-Yuan; Guo, Quan-Yi; Peng, Jiang; Lu, Shi-Bi

    2015-01-01

    Osteonecrosis of the femoral head (ONFH) is a type of common and refractory disease in the orthopedic clinic that is primarily caused by a partial obstruction of the blood supply to the femoral head, resulting in a series of pathological processes. Mesenchymal stem cells (MSCs) comprise a mixture of various stem cells in myeloid tissue with multipotential differentiation capacity. They can differentiate into bone cells under specific conditions and can be used to treat ONFH through cell transplantation. This review summarizes research on MSCs in the field of ONFH in recent years, reveals the inner characteristics of MSCs, describes their potential to treat osteonecrosis disease, and analyzes the existing challenges of using MSCs in clinical applications. PMID:26064202

  14. Osseous coagulum collected in bone traps: potential for bacterial contamination and methods for decontamination.

    PubMed

    Etcheson, Aaron W; Miley, D Douglas; Gillespie, M Jane

    2007-01-01

    Because of its excellent osteogenic potential, autogenous bone is the preferred grafting material for dental procedures; however, bone collected in osseous coagulum traps is subject to contamination by oral bacteria. This study assessed bacterial contamination of osseous coagulum and tested treatments for reducing contamination. Fifty bone samples from patients undergoing implant osteotomy procedures were collected in osseous coagulum traps, divided into groups of 10, and rinsed with normal saline, 0.12% chlorhexidine, or 50 mg/mL tetracycline. Twenty control samples received no treatment. The bone samples were plated in triplicate on selective and differential media to assay aerobic and anaerobic bacteria and potential bacterial pathogens, including staphylococci, streptococci, enterics, and black-pigmented bacteria (BPB). Inoculations were performed with an Autoplate 4000, and plates were incubated at 37 degrees C either aerobically or in a Coy anaerobic chamber. Bacteria were isolated from all samples. In control samples, the mean colony-forming units (cfu) per milliliter of suspended osseous coagulum was 6.5 x 10(4) +/- 9.6 x 10(4) in aerobic cultures and 4.8 x 10(4) +/- 6.9 x 10(4) in anaerobic cultures. Viridans streptococci were isolated from 46 samples, with a mean of 2.9 x 10(4) +/- 4.1 x 10(4) cfu/mL. Enterics were in 16 samples with cfu ranging from 200 cfu/mL to 3.4 x 10(4) cfu/mL. Mannitol nonfermenting staphylococci were found in one sample at 106 cfu/mL. BPB were not isolated. A Mann-Whitney U test with significance set at P = .05 determined that the only statistically significant reductions in bacterial numbers occurred in tetracycline-treated samples of anaerobic bacteria (5-fold decrease, P = .02) and aerobic bacteria (6-fold decrease, P = .01). Tetracycline treatments effected a 7-fold decrease in streptococci, but the difference was not significant (P = .07). These data indicate significant bacterial contamination of bone collected in osseous

  15. 3D-Printed Scaffolds and Biomaterials: Review of Alveolar Bone Augmentation and Periodontal Regeneration Applications

    PubMed Central

    Asa'ad, Farah; Giannì, Aldo Bruno; Giannobile, William V.; Rasperini, Giulio

    2016-01-01

    To ensure a successful dental implant therapy, the presence of adequate vertical and horizontal alveolar bone is fundamental. However, an insufficient amount of alveolar ridge in both dimensions is often encountered in dental practice due to the consequences of oral diseases and tooth loss. Although postextraction socket preservation has been adopted to lessen the need for such invasive approaches, it utilizes bone grafting materials, which have limitations that could negatively affect the quality of bone formation. To overcome the drawbacks of routinely employed grafting materials, bone graft substitutes such as 3D scaffolds have been recently investigated in the dental field. In this review, we highlight different biomaterials suitable for 3D scaffold fabrication, with a focus on “3D-printed” ones as bone graft substitutes that might be convenient for various applications related to implant therapy. We also briefly discuss their possible adoption for periodontal regeneration. PMID:27366149

  16. Spectroscopic investigation on formation and growth of mineralized nanohydroxyapatite for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Gopi, D.; Nithiya, S.; Shinyjoy, E.; Kavitha, L.

    Synthetic calcium hydroxyapatite (HAP,Ca10(PO4)6(OH)2) is a well-known bioceramic material used in orthopaedic and dental applications because of its excellent biocompatibility and bone-bonding ability. Substitution of trace elements, such as Sr, Mg and Zn ions into the structure of calcium phosphates is the subject of widespread investigation. In this paper, we have reported the synthesis of Sr, Mg and Zn co-substituted nanohydroxyapatite by soft solution freezing method. The effect of pH on the morphology of bioceramic nanomaterial was also discussed. The in vitro bioactivity of the as-synthesized bioceramic nanomaterial was determined by soaking it in SBF for various days. The as-synthesized bioceramic nanomaterial was characterized by Fourier transform infrared spectroscopy, X- ray diffraction analysis, Scanning electron microscopy and Energy dispersive X-ray analysis and Transmission electron microscopic techniques respectively. The results obtained in our study have revealed that pH 10 was identified to induce the formation of mineralized nanohydroxyapatite. It is observed that the synthesis of bioceramic nanomaterial not only support the growth of apatite layer on its surface but also accelerate the growth which is evident from the in vitro studies. Therefore, mineralized nanohydroxyapatite is a potential candidate in bone tissue engineering.

  17. [Study on the preparation and application of individual artificial bone with carbon/carbon composites].

    PubMed

    Ni, Xinye; Qian, Nong; Zhou, Dong; Miao, Yunliang; Xiong, Xinbo; Lin, Tao; Chen, Da; Zhao, Gongyin; Zhong, Ping

    2013-12-01

    The present paper is aimed to study the preparation and application of individual artificial bone of carbon/carbon composites. Using computer tomography images (CT), we acquired a three-dimensional image. Firstly, we described bone contour line outlined with manual and automatic method by the binary volume data. Secondly, we created 3D object surface information by marching cubes. Finally, we converted this information to non-uniform rational B-spine (NURBS) by using geomagic software. Individual artificial bone with carbon/carbon composite was prepared through the CNC Machining Center. We replaced the humeral head of the tested rabbit, and then observed the effects of implantation in neuroimaging and pathological section. Using this method, we found that the bone shape processed and bone shape replaced was consistent. After implantation, the implant and the surrounding bone tissue bound closely, and bone tissue grew well on the surface of the implant. It has laid a sound foundation of the preparation using this method for individual artificial bone of carbon/carbon composite material. PMID:24645609

  18. Auditory brainstem and cortical potentials following bone-anchored hearing aid stimulation.

    PubMed

    Rahne, Torsten; Ehelebe, Thomas; Rasinski, Christine; Götze, Gerrit

    2010-11-30

    Patients suffering from conductive or mixed hearing loss and Single-Sided Deafness may benefit from implantable hearing devices relying on bone conducted auditory stimulation. However, with only passively cooperative patients, objective methods are needed to estimate the aided and unaided pure-tone audiogram. This study focuses on the feasibility aspect of an electrophysiological determination of the hearing thresholds with bone-anchored hearing aid stimulation. Therefore, 10 normal-hearing subjects were provided with a Baha Intenso (Cochlear Ltd.) which was temporarily connected to the Baha Softband (Cochlear Ltd.). Auditory evoked potentials were measured by auditory stimulation paradigm used in clinical routine. The amplitudes, latencies, and thresholds of the resulting auditory brainstem responses (ABR) and the cortically evoked responses (CAEP) were correlated with the respective responses without the use of the Baha Intenso. The recording of ABR and CAEP by delivering the stimuli to the Baha results in response waveforms which are comparable to those evoked by earphone stimulation and appears appropriate to be measured using the Baha Intenso as stimulator. At the ABR recordings a stimulus artifact at higher stimulation levels and a constant latency shift caused by the Baha Intenso has to be considered. The CAEP recording appeared promising as a frequency specific objective method to approve the fitting of bone-anchored hearing aids. At all measurements, the ABR and CAEP thresholds seem to be consistent with the normal hearing of the investigated participants. Thus, a recording of auditory evoked potentials using a Baha is in general possible if specific limitations are considered. PMID:20875458

  19. ECM microenvironment unlocks brown adipogenic potential of adult human bone marrow-derived MSCs.

    PubMed

    Lee, Michelle H; Goralczyk, Anna G; Kriszt, Rókus; Ang, Xiu Min; Badowski, Cedric; Li, Ying; Summers, Scott A; Toh, Sue-Anne; Yassin, M Shabeer; Shabbir, Asim; Sheppard, Allan; Raghunath, Michael

    2016-01-01

    Key to realizing the diagnostic and therapeutic potential of human brown/brite adipocytes is the identification of a renewable, easily accessible and safe tissue source of progenitor cells, and an efficacious in vitro differentiation protocol. We show that macromolecular crowding (MMC) facilitates brown adipocyte differentiation in adult human bone marrow mesenchymal stem cells (bmMSCs), as evidenced by substantially upregulating uncoupling protein 1 (UCP1) and uncoupled respiration. Moreover, MMC also induced 'browning' in bmMSC-derived white adipocytes. Mechanistically, MMC creates a 3D extracellular matrix architecture enshrouding maturing adipocytes in a collagen IV cocoon that is engaged by paxillin-positive focal adhesions also at the apical side of cells, without contact to the stiff support structure. This leads to an enhanced matrix-cell signaling, reflected by increased phosphorylation of ATF2, a key transcription factor in UCP1 regulation. Thus, tuning the dimensionality of the microenvironment in vitro can unlock a strong brown potential dormant in bone marrow. PMID:26883894

  20. ECM microenvironment unlocks brown adipogenic potential of adult human bone marrow-derived MSCs

    PubMed Central

    Lee, Michelle H.; Goralczyk, Anna G.; Kriszt, Rókus; Ang, Xiu Min; Badowski, Cedric; Li, Ying; Summers, Scott A.; Toh, Sue-Anne; Yassin, M. Shabeer; Shabbir, Asim; Sheppard, Allan; Raghunath, Michael

    2016-01-01

    Key to realizing the diagnostic and therapeutic potential of human brown/brite adipocytes is the identification of a renewable, easily accessible and safe tissue source of progenitor cells, and an efficacious in vitro differentiation protocol. We show that macromolecular crowding (MMC) facilitates brown adipocyte differentiation in adult human bone marrow mesenchymal stem cells (bmMSCs), as evidenced by substantially upregulating uncoupling protein 1 (UCP1) and uncoupled respiration. Moreover, MMC also induced ‘browning’ in bmMSC-derived white adipocytes. Mechanistically, MMC creates a 3D extracellular matrix architecture enshrouding maturing adipocytes in a collagen IV cocoon that is engaged by paxillin-positive focal adhesions also at the apical side of cells, without contact to the stiff support structure. This leads to an enhanced matrix-cell signaling, reflected by increased phosphorylation of ATF2, a key transcription factor in UCP1 regulation. Thus, tuning the dimensionality of the microenvironment in vitro can unlock a strong brown potential dormant in bone marrow. PMID:26883894

  1. The in situ mechanics of trabecular bone marrow: the potential for mechanobiological response.

    PubMed

    Metzger, Thomas A; Kreipke, Tyler C; Vaughan, Ted J; McNamara, Laoise M; Niebur, Glen L

    2015-01-01

    Bone adapts to habitual loading through mechanobiological signaling. Osteocytes are the primary mechanical sensors in bone, upregulating osteogenic factors and downregulating osteoinhibitors, and recruiting osteoclasts to resorb bone in response to microdamage accumulation. However, most of the cell populations of the bone marrow niche,which are intimately involved with bone remodeling as the source of bone osteoblast and osteoclast progenitors, are also mechanosensitive. We hypothesized that the deformation of trabecular bone would impart mechanical stress within the entrapped bone marrow consistent with mechanostimulation of the constituent cells. Detailed fluid-structure interaction models of porcine femoral trabecular bone and bone marrow were created using tetrahedral finite element meshes. The marrow was allowed to flow freely within the bone pores, while the bone was compressed to 2000 or 3000 microstrain at the apparent level.Marrow properties were parametrically varied from a constant 400 mPas to a power law rule exceeding 85 Pas. Deformation generated almost no shear stress or pressure in the marrow for the low viscosity fluid, but exceeded 5 Pa when the higher viscosity models were used. The shear stress was higher when the strain rate increased and in higher volume fraction bone. The results demonstrate that cells within the trabecular bone marrow could be mechanically stimulated by bone deformation, depending on deformation rate, bone porosity, and bone marrow properties. Since the marrow contains many mechanosensitive cells, changes in the stimulatory levels may explain the alterations in bone marrow morphology with aging and disease, which may in turn affect the trabecular bone mechanobiology and adaptation. PMID:25363343

  2. Therapeutic potential of bone marrow-derived mesenchymal stem cells for cutaneous wound healing.

    PubMed

    Chen, Jerry S; Wong, Victor W; Gurtner, Geoffrey C

    2012-01-01

    Despite advances in wound care, many wounds never heal and become chronic problems that result in significant morbidity and mortality to the patient. Cellular therapy for cutaneous wounds has recently come under investigation as a potential treatment modality for impaired wound healing. Bone marrow-derived mesenchymal stem cells (MSCs) are a promising source of adult progenitor cells for cytotherapy as they are easy to isolate and expand and have been shown to differentiate into various cell lineages. Early studies have demonstrated that MSCs may enhance epithelialization, granulation tissue formation, and neovascularization resulting in accelerated wound closure. It is currently unclear if these effects are mediated through cellular differentiation or by secretion of cytokines and growth factors. This review discusses the proposed biological contributions of MSCs to cutaneous repair and their clinical potential in cell-based therapies. PMID:22787462

  3. Alendronate-decorated biodegradable polymeric micelles for potential bone-targeted delivery of vancomycin.

    PubMed

    Cong, Yingying; Quan, Changyun; Liu, Meiqing; Liu, Jie; Huang, Gang; Tong, Guoquan; Yin, Yihua; Zhang, Chao; Jiang, Qing

    2015-01-01

    Osteomyelitis is a bone infection disease which is caused by bacteria or other germs, and could cause serious impact on the health and working capacity of the patients. Alendronate (ALN) can chelate strongly with the calcium ion of hydroxyapatite (HA) which is commonly used to treat osteoporosis. Nanomedicine has attracted a lot of attention in that the nano-sized carrier can deliver drug molecules to specific site of interest with the aid of targeting moiety and achieve sustained release, resulting in improved therapeutic effect and reduced side effect. In this study, micelles self-assembled from poly(lactic acid-co-glycolic acid)-block-poly(ethylene glycol)-alendronate (PLGA-PEG-ALN) copolymer were prepared for bone-targeted delivery of vancomycin (Van). The chemical structure of PLGA-PEG-ALN was confirmed by proton nuclear magnetic resonance ((1)H-NMR) spectroscopy. The formation of the nanoparticles was characterized by dynamic light scattering, transmission electronic microscopy as well as the critical micelle concentration measurement. Release profiles from the micelles revealed that the conjugation of ALN to the surface of micelle did not pose adverse effect on the drug-loading capacity and release behaviors. The cytotoxicity of Van-loaded PLGA-PEG-ALN micelles as well as the blank micelles was evaluated via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay toward rat bone marrow stromal cells (rBMSCs) and human embryonic hepatocytes (L02 cells), and results showed that this Van-loaded micelle possesses appropriate cytotoxicity and is safe in the potential treatment of osteomyelitis. The in vitro affinity of PLGA-PEG-ALN micelles to the HA was also confirmed in vitro. The antibacterial effect of Van-loaded PLGA-PEG-ALN micelles was tested against Staphylococcus aureus (SA) which is the main pathogenic bacteria in osteomyelitis, and the results showed that the Van-loaded micelles can effectively inhibit the growth of SA. These results

  4. Conotoxins: Structure, Therapeutic Potential and Pharmacological Applications.

    PubMed

    Mir, Rafia; Karim, Sajjad; Kamal, Mohammad Amjad; Wilson, Cornelia M; Mirza, Zeenat

    2016-01-01

    Cone snails, also known as marine gastropods, from Conus genus produce in their venom a diverse range of small pharmacologically active structured peptides called conotoxins. The cone snail venoms are widely unexplored arsenal of toxins with therapeutic and pharmacological potential, making them a treasure trove of ligands and peptidic drug leads. Conotoxins are small disulfide bonded peptides, which act as remarkable selective inhibitors and modulators of ion channels (calcium, sodium, potassium), nicotinic acetylcholine receptors, noradrenaline transporters, N-methyl-D-aspartate receptors, and neurotensin receptors. They are highly potent and specific against several neuronal targets making them valuable as research tools, drug leads and even therapeutics. In this review, we discuss their gene superfamily classification, nomenclature, post-translational modification, structural framework, pharmacology and medical applications of the active conopeptides. We aim to give an overview of their structure and therapeutic potential. Understanding these aspects of conopeptides will help in designing more specific peptidic analogues. PMID:26601961

  5. Investigation of immiscible systems and potential applications

    NASA Technical Reports Server (NTRS)

    Markworth, A. J.; Oldfield, W.; Duga, J.; Gelles, S. H.

    1975-01-01

    The droplet coalescence kinetics at 0 g and 1 g were considered for two systems which contained liquid droplets in a host liquid. One of these (Al-In) typified a system containing a liquid phase miscibility gap and the order (oil-water) a mixture of two essentially insoluble liquids. A number of coalescence mechanisms potentially prominent at low g in this system were analyzed and explanations are presented for the observed unusual stability of the emulsion. Ground base experiments were conducted on the coalescence of In droplets in and Al-In alloy during cooling through the miscibility gap at different cooling rates. These were in qualitative agreement with the computer simulation. Potential applications for systems with liquid phase miscibility gaps were explored. Possibilities included superconductors, electrical contact materials, superplastic materials, catalysts, magnetic materials, and others. The role of space processing in their production was also analyzed.

  6. Application potential of Fe-based superconductors

    NASA Astrophysics Data System (ADS)

    Pallecchi, Ilaria; Eisterer, Michael; Malagoli, Andrea; Putti, Marina

    2015-11-01

    In this paper we report basic properties of iron-based superconductors and review the latest achievements in the fabrication of conductors based on these materials. We compare state-of-the-art results with performances obtained with low-T c and high-T c technical superconductors, evidencing in particular the most significant differences with respect to high-T c cuprate coated conductors. Although the optimization of preparation procedures is yet to be established, a potential range of applications for iron-based superconductors in the high field low temperature regime can be envisaged, where they may become competitors to RE-123 coated conductors.

  7. Potential aerospace applications of high temperature superconductors

    NASA Astrophysics Data System (ADS)

    Selim, Raouf

    1994-12-01

    The recent discovery of High Temperature Superconductors (HTS) with superconducting transition temperature, T(sub c), above the boiling point of liquid nitrogen has opened the door for using these materials in new and practical applications. These materials have zero resistance to electric current, have the capability of carrying large currents and as such have the potential to be used in high magnetic field applications. One of the space applications that can use superconductors is electromagnetic launch of payloads to low-earth-orbit. An electromagnetic gun-type launcher can be used in small payload systems that are launched at very high velocity, while sled-type magnetically levitated launcher can be used to launch larger payloads at smaller velocities. Both types of launchers are being studied by NASA and the aerospace industry. The use of superconductors will be essential in any of these types of launchers in order to produce the large magnetic fields required to obtain large thrust forces. Low Temperature Superconductor (LTS) technology is mature enough and can be easily integrated in such systems. As for the HTS, many leading companies are currently producing HTS coils and magnets that potentially can be mass-produced for these launchers. It seems that designing and building a small-scale electromagnetic launcher is the next logical step toward seriously considering this method for launching payloads into low-earth-orbit. A second potential application is the use of HTS to build sensitive portable devices for the use in Non Destructive Evaluation (NDE). Superconducting Quantum Interference Devices (SQUID's) are the most sensitive instruments for measuring changes in magnetic flux. By using HTS in SQUID's, one will be able to design a portable unit that uses liquid nitrogen or a cryocooler pump to explore the use of gradiometers or magnetometers to detect deep cracks or corrosion in structures. A third use is the replacement of Infra-Red (IR) sensor leads on

  8. Potential aerospace applications of high temperature superconductors

    NASA Technical Reports Server (NTRS)

    Selim, Raouf

    1994-01-01

    The recent discovery of High Temperature Superconductors (HTS) with superconducting transition temperature, T(sub c), above the boiling point of liquid nitrogen has opened the door for using these materials in new and practical applications. These materials have zero resistance to electric current, have the capability of carrying large currents and as such have the potential to be used in high magnetic field applications. One of the space applications that can use superconductors is electromagnetic launch of payloads to low-earth-orbit. An electromagnetic gun-type launcher can be used in small payload systems that are launched at very high velocity, while sled-type magnetically levitated launcher can be used to launch larger payloads at smaller velocities. Both types of launchers are being studied by NASA and the aerospace industry. The use of superconductors will be essential in any of these types of launchers in order to produce the large magnetic fields required to obtain large thrust forces. Low Temperature Superconductor (LTS) technology is mature enough and can be easily integrated in such systems. As for the HTS, many leading companies are currently producing HTS coils and magnets that potentially can be mass-produced for these launchers. It seems that designing and building a small-scale electromagnetic launcher is the next logical step toward seriously considering this method for launching payloads into low-earth-orbit. A second potential application is the use of HTS to build sensitive portable devices for the use in Non Destructive Evaluation (NDE). Superconducting Quantum Interference Devices (SQUID's) are the most sensitive instruments for measuring changes in magnetic flux. By using HTS in SQUID's, one will be able to design a portable unit that uses liquid nitrogen or a cryocooler pump to explore the use of gradiometers or magnetometers to detect deep cracks or corrosion in structures. A third use is the replacement of Infra-Red (IR) sensor leads on

  9. Innovations in acrylic bone cement and application equipment.

    PubMed

    Kindt-Larsen, T; Smith, D B; Jensen, J S

    1995-01-01

    A new bone cement was developed with the purpose of reducing the adverse biological effects during cementation of implants. This bone cement is characterized by lower exotherm, low release of monomer, low residual content of monomer, and retained physical properties. The essential innovation was substitution of half of the methylmethacrylate (MMA) in the monomer with long chain, high molecular weight, less volatile, and less soluble methacrylates (n-decylmethacrylate, isobornyl-methacrylate), as well as alteration of the accelerator system to a mix of dihydroxypropyl-p-toluidine and N,N-dimethyl-p-toluidine. The powder contains butylmethacrylate-MMA copolymers. These measures lower the glass-transition temperature, and permit more complete mixing in an integrated package, mixing, and delivery system consisting of a vacuum packed, double chamber pouch. The porosity was reduced to about 2% and the largest voids measured 0.1 mm. The polymerization exotherm was reduced to 58 degrees C. The compressive strength was 82 MPa, the four-point bending strength 55 MPa, the flexural modulus 2.24 GPa, the tensile strength 32 MPa, and the shear strength 36 MPa. The fracture toughness was 0.89 MPa square root of cm. These mechanical properties together with the fatigue life were on level with manually mixed, conventional PMMA bone cements. PMID:7703541

  10. Analysis of calvarial bone defects in rats using microcomputed tomography: potential for a novel composite material and a new quantitative measurement.

    PubMed

    Efeoglu, Candan; Burke, Julie L; Parsons, Andrew J; Aitchison, Graham A; Scotchford, Colin; Rudd, Chris; Vikram, Aditya; Fisher, Sheila E

    2009-12-01

    Reconstruction of craniomaxillofacial defects is a challenge for surgeons and has psychological and functional burdens for patients. Undoubtedly, there is a need for improved biomaterials and techniques for craniomaxillofacial reconstruction. We assessed the potential regeneration of bone using three modifications of a novel composite and explored the validity of a new measurement using microcomputed tomography (micro-CT). We placed three different composite samples in calvarial defects in rats and analysed healing with micro-CT. The results showed that polycaprolactone (PCL) with phosphate glass fibre is promising for non-load bearing applications in the craniomaxillofacial region. Also, the new micro-CT measurement of the temporal characterisation of the mineralisation of bone (TCBM) has the potential to evolve into a reliable predictor of bony healing and its quality. PMID:19395133

  11. WISP1/CCN4: A Potential Target for Inhibiting Prostate Cancer Growth and Spread to Bone

    PubMed Central

    Sonn, Robert; Kilts, Tina M.; de Castro, Luis F.; Maeda, Azusa; Fisher, Larry W.; Robey, Pamela G.; Berendsen, Agnes D.; Li, Li; McCartney-Francis, Nancy; Brown, Aaron C.; Crawford, Nigel P. S.; Molinolo, Alfredo; Jain, Alka; Fedarko, Neal S.; Young, Marian F.

    2013-01-01

    Prostate cancer (PC) is a leading cause of death in men however the factors that regulate its progression and eventual metastasis to bone remain unclear. Here we show that WISP1/CCN4 expression in prostate cancer tissues was up-regulated in early stages of the disease and, further, that it correlated with increased circulating levels of WISP1 in the sera of patients at early stages of the disease. WISP1 was also elevated in the mouse prostate cancer model TRAMP in the hypoplastic diseased tissue that develops prior to advanced carcinoma formation. When the ability of anti-WISP1 antibodies to reduce the spread of PC3-Luc cells to distant sites was tested it showed that twice weekly injections of anti-WISP1 antibodies reduced the number and overall size of distant tumors developed after intracardiac (IC) injection of PC3-Luc cells in mice. The ability of antibodies against WISP1 to inhibit growth of PC3-Luc cancer cells in mice was also evaluated and showed that twice weekly injections of anti-WISP1 antibodies reduced local tumor growth when examined in xenografts. To better understand the mechanism of action, the migration of PC3-Luc cells through membranes with or without a Matrigel™ barrier showed the cells were attracted to WISP1, and that this attraction was inhibited by treatment with anti-WISP1 antibodies. We also show the expression of WISP1 at the bone-tumor interface and in the stroma of early grade cancers suggested WISP1 expression is well placed to play roles in both fostering growth of the cancer and its spread to bone. In summary, the up-regulation of WISP1 in the early stages of cancer development coupled with its ability to inhibit spread and growth of prostate cancer cells makes it both a potential target and an accessible diagnostic marker for prostate cancer. PMID:23977121

  12. Engineering interaction between bone marrow derived endothelial cells and electrospun surfaces for artificial vascular graft applications.

    PubMed

    Ahmed, Furqan; Dutta, Naba K; Zannettino, Andrew; Vandyke, Kate; Choudhury, Namita Roy

    2014-04-14

    The aim of this investigation was to understand and engineer the interactions between endothelial cells and the electrospun (ES) polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) nanofiber surfaces and evaluate their potential for endothelialization. Elastomeric PVDF-HFP samples were electrospun to evaluate their potential use as small diameter artificial vascular graft scaffold (SDAVG) and compared with solvent cast (SC) PVDF-HFP films. We examined the consequences of fibrinogen adsorption onto the ES and SC samples for endothelialisation. Bone marrow derived endothelial cells (BMEC) of human origin were incubated with the test and control samples and their attachment, proliferation, and viability were examined. The nature of interaction of fibrinogen with SC and ES samples was investigated in detail using ELISA, XPS, and FTIR techniques. The pristine SC and ES PVDF-HFP samples displayed hydrophobic and ultrahydrophobic behavior and accordingly, exhibited minimal BMEC growth. Fibrinogen adsorbed SC samples did not significantly enhance endothelial cell binding or proliferation. In contrast, the fibrinogen adsorbed electrospun surfaces showed a clear ability to modulate endothelial cell behavior. This system also represents an ideal model system that enables us to understand the natural interaction between cells and their extracellular environment. The research reported shows potential of ES surfaces for artificial vascular graft applications. PMID:24564790

  13. Preparation of collagen/hydroxyapatite/alendronate hybrid hydrogels as potential scaffolds for bone regeneration.

    PubMed

    Ma, Xin; He, Zhiwei; Han, Fengxuan; Zhong, Zhiyuan; Chen, Liang; Li, Bin

    2016-07-01

    Development of biomimetic scaffolds represents a promising direction in bone tissue engineering. In this study, we designed a two-step process to prepare a type of biomimetic hybrid hydrogels that were composed of collagen, hydroxyapatite (HAP) and alendronate (ALN), an anti-osteoporosis drug. First, water-soluble ALN-conjugated HAP (HAP-ALN) containing 4.0wt.% of ALN was synthesized by treating HAP particles with ALN. Hydrogels were then formed from HAP-ALN conjugate and collagen under physiological conditions using genipin (GNP) as the crosslinker. Depending on the ALN/collagen molar ratio and GNP concentration, the gelation time of hydrogels ranged from 5 to 37min. Notably, these hybrid hydrogels exhibited markedly improved mechanical property (storage modulus G'=38-187kPa), higher gel contents, and lower swelling ratios compared to the hydrogels prepared from collagen alone under similar conditions. Moreover, they showed tunable degradation behaviors against collagenase. The collagen/HAP-ALN hybrid hydrogels supported the adhesion and growth of murine MC3T3-E1 osteoblastic cells well. Such tough yet enzymatically degradable hybrid hydrogels hold potential as scaffolds for bone tissue engineering. PMID:26998869

  14. A facile magnesium-containing calcium carbonate biomaterial as potential bone graft.

    PubMed

    He, Fupo; Zhang, Jing; Tian, Xiumei; Wu, Shanghua; Chen, Xiaoming

    2015-12-01

    The calcium carbonate is the main composition of coral which has been widely used as bone graft in clinic. Herein, we readily prepared novel magnesium-containing calcium carbonate biomaterials (MCCs) under the low-temperature conditions based on the dissolution-recrystallization reaction between unstable amorphous calcium carbonate (ACC) and metastable vaterite-type calcium carbonate with water involved. The content of magnesium in MCCs was tailored by adjusting the proportion of ACC starting material that was prepared using magnesium as stabilizer. The phase composition of MCCs with various amounts of magnesium was composed of one, two or three kinds of calcium carbonates (calcite, aragonite, and/or magnesian calcite). The different MCCs differed in topography. The in vitro degradation of MCCs accelerated with increasing amount of introduced magnesium. The MCCs with a certain amount of magnesium not only acquired higher compressive strength, but also promoted in vitro cell proliferation and osteogenic differentiation. Taken together, the facile MCCs shed light on their potential as bone graft. PMID:26539810

  15. In vivo study of porous strontium-doped calcium polyphosphate scaffolds for bone substitute applications.

    PubMed

    Tian, Meng; Chen, Feng; Song, Wei; Song, Yancheng; Chen, Yuanwei; Wan, Changxiu; Yu, Xixun; Zhang, Xiaohua

    2009-07-01

    The purpose of this study was to investigate in vivo biocompatibility and osteogenesis as well as degradability of the porous strontium-doped calcium polyphosphate (SCPP) scaffolds as a biomaterial for bone substitute applications. The evaluation was performed on a rabbit model over a period of 16 weeks by histology combined with image analysis, X-ray microradiography and immunohistochemistry methods. The histological and X-ray microradiographic results showed that the SCPP scaffold exhibited good biocompatibility and extensive osteoconductivity with host bone. Moreover, a significant more bone formation was observed in the SCPP group compared with that in the CPP group, especially at the initial stage after implantation. New bone volumes (NBVs) of the SCPP group determined at week 4, 8 and 16 were 14, 27 and 45%, respectively. Accordingly, NBVs of the CPP group were 10, 19 and 40%. Immunohistochemical results revealed that both the expression of collagen type I and bone morphogenetic proteins in the SCPP group were higher than that in the CPP group, which might be associated with the release of strontium ions during the implantation. In addition, during 16 weeks implantation the SCPP scaffold exhibited similar degradability with the CPP scaffold in vivo. Both scaffolds showed the greatest degradation rate for the first 4 weeks, and then the degradation rate gradually decreased. The results presented in this study demonstrated that SCPP scaffold can be considered as a biocompatible material, making it attractive for bone substitute application purposes. PMID:19267259

  16. Potential role of the OPG/RANK/RANKL axis in prostate cancer invasion and bone metastasis.

    PubMed

    Li, Xiaoming; Liu, Yaoming; Wu, Bin; Dong, Zhilong; Wang, Yichen; Lu, Jianzhong; Shi, Ping; Bai, Wenlong; Wang, Zhiping

    2014-12-01

    invasion. Our findings indicate that the expression of RANK, RANKL and OPG may be used as diagnostic markers to identify patients at high risk for aggressive PCa and that the effective suppression of PCa cell migration by OPG via the blockage of RANKL activity represents a potential therapeutic strategy for interfering with prostate tumor metastasis and progression to bone. PMID:25333856

  17. POTENTIAL THERMOELECTRIC APPLICATIONS IN DIESEL VEHICLES

    SciTech Connect

    Crane, D

    2003-08-24

    Novel thermodynamic cycles developed by BSST provide improvements by factors of approximately 2 in cooling, heating and power generation efficiency of solid-state thermoelectric systems. The currently available BSST technology is being evaluated in automotive development programs for important new applications. Thermoelectric materials are likely to become available that further increase performance by a comparable factor. These major advancements should allow the use of thermoelectric systems in new applications that have the prospect of contributing to emissions reduction, fuel economy, and improved user comfort. Potential applications of thermoelectrics in diesel vehicles are identified and discussed. As a case in point, the history and status of the Climate Controlled Seat (CCS) system from Amerigon, the parent of BSST, is presented. CCS is the most successful and highest production volume thermoelectric system in vehicles today. As a second example, the results of recent analyses on electric power generation from vehicle waste heat are discussed. Conclusions are drawn as to the practicality of waste power generation systems that incorporate BSST's thermodynamic cycle and advanced thermoelectric materials.

  18. Raloxifene: Mechanism of Action, Effects on Bone Tissue, and Applicability in Clinical Traumatology Practice

    PubMed Central

    Rey, Jose R. Caeiro; Cervino, Eduardo Vaquero; Rentero, Maria Luz; Crespo, Emilio Calvo; Álvaro, Angel Oteo; Casillas, Marta

    2009-01-01

    Raloxifene, a member of the class of selective estrogen receptor modulators (SERM), reproduces the beneficial effects of estrogens on the skeletal systems, without the negative effects estrogens on breast and endometrium. This is a review article summarizing its mechanism, effects on bone and its applicability in traumatology clinical practice. In postmenopausal osteoporosis, this drug has been proven to decrease accelerated bone turnover, increase bone mineral density (BMD), and to structurally recover bone, decreasing the risk of vertebral fractures and the risk of non-vertebral fractures in patients with previous, severe vertebral fractures. Moreover, raloxifene appears to lower the risk of invasive breast cancer. Raloxifene would be efficacious in the prevention and treatment of postmenopausal osteoporosis. We can therefore conclude that raloxifene would be efficacious in the prevention and treatment of postmenopausal osteoporosis, while reducing the risk of breast cancer when used at the indicated dose of 60 mg/day and with a low incidence of side effects. PMID:19516920

  19. Marine bioactives and potential application in sports.

    PubMed

    Gammone, Maria Alessandra; Gemello, Eugenio; Riccioni, Graziano; D'Orazio, Nicolantonio

    2014-05-01

    An enriched diet with antioxidants, such as vitamin E, vitamin C, β-carotene and phenolic compounds, has always been suggested to improve oxidative stress, preventing related diseases. In this respect, marine natural product (MNP), such as COX inhibitors, marine steroids, molecules interfering with factors involved in the modulation of gene expression (such as NF-κB), macrolides, many antioxidant agents, thermogenic substances and even substances that could help the immune system and that result in the protection of cartilage, have been recently gaining attention. The marine world represents a reserve of bioactive ingredients, with considerable potential as functional food. Substances, such as chitin, chitosan, n-3 oils, carotenoids, vitamins, minerals and bioactive peptides, can provide several health benefits, such as the reduction of cardiovascular diseases, anti-inflammatory and anticarcinogenic activities. In addition, new marine bioactive substances with potential anti-inflammatory, antioxidant and thermogenic capacity may provide health benefits and performance improvement, especially in those who practice physical activity, because of their increased free radical and Reacting Oxygen Species (ROS) production during exercise, and, particularly, in athletes. The aim of this review is to examine the potential pharmacological properties and application of many marine bioactive substances in sports. PMID:24796298

  20. Marine Bioactives and Potential Application in Sports

    PubMed Central

    Gammone, Maria Alessandra; Gemello, Eugenio; Riccioni, Graziano; D’Orazio, Nicolantonio

    2014-01-01

    An enriched diet with antioxidants, such as vitamin E, vitamin C, β-carotene and phenolic compounds, has always been suggested to improve oxidative stress, preventing related diseases. In this respect, marine natural product (MNP), such as COX inhibitors, marine steroids, molecules interfering with factors involved in the modulation of gene expression (such as NF-κB), macrolides, many antioxidant agents, thermogenic substances and even substances that could help the immune system and that result in the protection of cartilage, have been recently gaining attention. The marine world represents a reserve of bioactive ingredients, with considerable potential as functional food. Substances, such as chitin, chitosan, n-3 oils, carotenoids, vitamins, minerals and bioactive peptides, can provide several health benefits, such as the reduction of cardiovascular diseases, anti-inflammatory and anticarcinogenic activities. In addition, new marine bioactive substances with potential anti-inflammatory, antioxidant and thermogenic capacity may provide health benefits and performance improvement, especially in those who practice physical activity, because of their increased free radical and Reacting Oxygen Species (ROS) production during exercise, and, particularly, in athletes. The aim of this review is to examine the potential pharmacological properties and application of many marine bioactive substances in sports. PMID:24796298

  1. Supercritical carbon dioxide-processed resorbable polymer nanocomposites for bone graft substitute applications

    NASA Astrophysics Data System (ADS)

    Baker, Kevin C.

    Numerous clinical situations necessitate the use of bone graft materials to enhance bone formation. While autologous and allogenic materials are considered the gold standards in the setting of fracture healing and spine fusion, their disadvantages, which include donor site morbidity and finite supply have stimulated research and development of novel bone graft substitute materials. Among the most promising candidate materials are resorbable polymers, composed of lactic and/or glycolic acid. While the characteristics of these materials, such as predictable degradation kinetics and biocompatibility, make them an excellent choice for bone graft substitute applications, they lack mechanical strength when synthesized with the requisite porous morphology. As such, porous resorbable polymers are often reinforced with filler materials. In the presented work, we describe the use of supercritical carbon dioxide (scCO2) processing to create porous resorbable polymeric constructs reinforced by nanostructured, organically modified Montmorillonite clay (nanoclay). scCO2 processing simultaneously disperses the nanoclay throughout the polymeric matrix, while imparting a porous morphology to the construct conducive to facilitating cellular infiltration and neoangiogenesis, which are necessary components of bone growth. With the addition of as little as 2.5wt% of nanoclay, the compressive strength of the constructs nearly doubles putting them on par with human cortico-cancellous bone. Rheological measurements indicate that the dominant mode of reinforcement of the nanocomposite constructs is the restriction of polymer chain mobility. This restriction is a function of the positive interaction between polymer chains and the nanoclay. In vivo inflammation studies indicate biocompatibility of the constructs. Ectopic osteogenesis assays have determined that the scCO2-processed nanocomposites are capable of supporting growth-factor induced bone formation. scCO 2-processed resorbable

  2. Consensus on the utility of bone markers in the malignant bone disease setting.

    PubMed

    Coleman, Robert; Costa, Luis; Saad, Fred; Cook, Richard; Hadji, Peyman; Terpos, Evangelos; Garnero, Patrick; Brown, Janet; Body, Jean-Jacques; Smith, Matthew; Lee, Ker-Ai; Major, Pierre; Dimopoulos, Meletios; Lipton, Allan

    2011-12-01

    Biochemical markers of bone turnover provide insight into ongoing rates of skeletal metabolism and tumor-bone interactions in patients with malignant bone disease. This article reviews the available recent evidence assessing the potential of bone markers for detecting and monitoring malignant bone lesions in patients with advanced cancers, and for assessing overall skeletal health and response to antiresorptive therapies in patients at all stages of cancer progression. Most data thus far are for urinary N-terminal cross-linked telopeptide of type I collagen (NTX) in predicting risks of skeletal morbidity and death and monitoring response to zoledronic acid in patients with bone metastases. Ongoing studies are evaluating such correlations for other markers and therapies. Emerging evidence suggests that bone markers may help identify patients at high risk for bone metastasis or bone lesion progression, thereby allowing improved follow-up. Results from ongoing clinical trials evaluating such potential applications of bone markers are awaited. PMID:21411334

  3. Bone morphogenetic protein-4 strongly potentiates growth factor-induced proliferation of mammary epithelial cells

    SciTech Connect

    Montesano, Roberto Sarkoezi, Rita; Schramek, Herbert

    2008-09-12

    Bone morphogenetic proteins (BMPs) are multifunctional cytokines that elicit pleiotropic effects on biological processes such as cell proliferation, cell differentiation and tissue morphogenesis. With respect to cell proliferation, BMPs can exert either mitogenic or anti-mitogenic activities, depending on the target cells and their context. Here, we report that in low-density cultures of immortalized mammary epithelial cells, BMP-4 did not stimulate cell proliferation by itself. However, when added in combination with suboptimal concentrations of fibroblast growth factor (FGF)-2, FGF-7, FGF-10, epidermal growth factor (EGF) or hepatocyte growth factor (HGF), BMP-4 potently enhanced growth factor-induced cell proliferation. These results reveal a hitherto unsuspected interplay between BMP-4 and growth factors in the regulation of mammary epithelial cell proliferation. We suggest that the ability of BMP-4 to potentiate the mitogenic activity of multiple growth factors may contribute to mammary gland ductal morphogenesis as well as to breast cancer progression.

  4. Fibrin gel-immobilized primary osteoblasts in calcium phosphate bone cement: in vivo evaluation with regard to application as injectable biological bone substitute.

    PubMed

    Kneser, U; Voogd, A; Ohnolz, J; Buettner, O; Stangenberg, L; Zhang, Y H; Stark, G B; Schaefer, D J

    2005-01-01

    Osteogenic injectable bone substitutes may be useful for many applications. We developed a novel injectable bone substitute based on osteoblast-fibrin glue suspension and calcium phosphate bone cement (BC). Human osteoblasts were isolated from trabecular bone samples and cultured under standard conditions. Osteoblasts were suspended in fibrinogen solution (FS). BC was cured with thrombin solution. 8 x 4 mm injectable bone discs were prepared using silicon molds and a custom-made applicator device. Discs containing BC, BC/FS, or BC/FS/osteoblasts were implanted subcutaneously into athymic nude mice. After 3, 9 and 24 weeks, specimens were explanted and subjected to morphologic and biomechanical evaluation. In vitro fibrin gel-embedded osteoblasts displayed a differentiated phenotype as evidenced by alkaline phosphatase, collagen type 1 and von Kossa stains. A proportion of osteoblasts appeared morphologically intact over a 3-day in vitro period following application into the BC. BC/FS and BC/FS/osteoblast discs were sparsely infiltrated with vascularized connective tissue. There was no bone formation in implants from all groups. However, positive von Kossa staining only in BC/FS/osteoblast groups suggests engraftment of at least some of the transplanted cells. Biomechanical evaluation demonstrated initial stability of the composites. Young's modulus and maximal load did not differ significantly in the BC/FS and BC/FS/osteoblast groups. The practicability of osteoblast-containing injectable bone could be demonstrated. The dense microstructure and the suboptimal initial vascularization of the composites may explain the lack of bone formation. Modifications with regard to enhanced osteoblast survival are mandatory for a possible application as injectable osteogenic bone replacement system. PMID:16046862

  5. Polymer-ceramic nanocomposites for applications in the bone surgery

    NASA Astrophysics Data System (ADS)

    Stodolak, E.; Gadomska, K.; Lacz, A.; Bogun, M.

    2009-01-01

    The subject of this work was preparation and investigation of properties of a nanocomposite material based on polymer matrix modified with nanometric silica particles (SiO2). The composite matrix consisted of resorbable P(L/DL)LA polymer with certified biocompatibility. Nanometric silica was introduced into the matrix by means of ultrasonic homogenisation and/or mechanical stirring. The silica was introduced directly e.g. as nanoparticles or inside calcium alginate fibres which contained 3 wt.% of amorphous SiO2. Proper dispersion of nano-filliers was confirmed by means of thermal analysis (TG/DTA, DSC). It was observed, that the presence of inorganic nanoparticles influenced several surface parameters of the nanocomposites i.e. hydrophility (a decrease of surface energy) and topography (both in micro- and nano-scale). Additionally, the nanocomposites exhibited enhanced mechanical properties (Young's modulus, tensile strength) compared to the pure polymer. The nanocomposites were bioactive materials (SBF/3 days/37oC). Biological tests (MTT test) showed a good viability of human osteoblasts (hFOB 1.19) in contact with the nanocomposites surface. Results of preliminary biological tests carried out with the use of mother cells extracted from human bone marrow showed that the nanocomposites may provide differenation of bone cells.

  6. Microfluidic desalination techniques and their potential applications.

    PubMed

    Roelofs, S H; van den Berg, A; Odijk, M

    2015-09-01

    In this review we discuss recent developments in the emerging research field of miniaturized desalination. Traditionally desalination is performed to convert salt water into potable water and research is focused on improving performance of large-scale desalination plants. Microfluidic desalination offers several new opportunities in comparison to macro-scale desalination, such as providing a platform to increase fundamental knowledge of ion transport on the nano- and microfluidic scale and new microfluidic sample preparation methods. This approach has also lead to the development of new desalination techniques, based on micro/nanofluidic ion-transport phenomena, which are potential candidates for up-scaling to (portable) drinking water devices. This review assesses microfluidic desalination techniques on their applications and is meant to contribute to further implementation of microfluidic desalination techniques in the lab-on-chip community. PMID:26226407

  7. Influence of irradiation on the osteoinductive potential of demineralized bone matrix.

    PubMed

    Wientroub, S; Reddi, A H

    1988-04-01

    Samples of demineralized bone matrix (DBM) were exposed to graduated doses of radiation (1-15 Megarad) (Mrad) utilizing a linear accelerator and then implanted into the thoracic region of Long-Evans rats. Subcutaneous implantation of DBM into allogenic rats induces endochondral bone. In response to matrix implantation, a cascade of events ensues; mesenchymal cell proliferation on day 3 postimplantation, chondrogenesis on day 7, calcification of the cartilagenous matrix and chondrolysis on day 9, and osteogenesis on day 11 resulting in formation of an ossicle containing active hemopoietic tissue. Bone formation was assessed by measuring alkaline phosphatase activity, the rate of mineralization was determined by measuring 45Ca incorporation to bone mineral, and 40Ca content measured the extent of mineralization; acid phosphatase activity was used as a parameter for bone resorption. The dose of radiation (2.5 Mrad) currently used by bone banks for sterilization of bone tissue did not destroy the bone induction properties of DBM. Furthermore, radiation of 3-5 Mrad even enhanced bone induction, insofar as it produced more bone at the same interval of time than was obtained from unirradiated control samples. None of the radiation doses used in these experiments abolished bone induction, although the response induced by matrix irradiated with doses higher than 5 Mrad was delayed. PMID:3135091

  8. Photoacoustic imaging: a potential new platform for assessment of bone health

    NASA Astrophysics Data System (ADS)

    Feng, Ting; Kozloff, Kenneth M.; Hsiao, Yi-Sing; Xu, Guan; Du, Sidan; Yuan, Jie; Deng, Cheri X.; Wang, Xueding

    2015-02-01

    The ultimate goal of this work is to develop a novel photoacoustic (QPA) platform for highly-sensitive and quantitative assessment of bone health. First, the feasibility to perform 3D photoacoustic imaging (PAI) of bone was investigated. Then another two techniques, including thermal photoacoustic measurement (TPAM) and photoacoustic spectral analysis (PASA), both being able to achieve quantitative results were investigated for bone characterization. TPAM, by evaluating the dependence of photoacoustic signal amplitude on the sample temperature, is sensitive to the chemical constituents in tissue and holds promise for assessment of bone mineral density (BMD). PASA characterizes micron size physical features in tissue, and has shown feasibility for objective assessment of bone microarchitecture (BMA). This integrated QPA platform can assess both bone mass and microstructure simultaneously without involving invasive biopsy or ionizing radiation. Since QPA is non-ionizing, non-invasive, and has sufficient penetration in both soft tissue and bone, it has unique advantages for clinical translation.

  9. Complex Macromolecular Architectures for Potential Biological Applications

    NASA Astrophysics Data System (ADS)

    Jung, Hwayoon

    This thesis describes original research aimed at the development of highly efficient synthetic methods towards complex polymer architectures. An explanation of different polymer architectures, their synthesis and applications, in particular as biomaterials, is provided. Dendronized polymers and block copolymers are identified as two classes of polymer architectures that are important for a variety of applications but whose fabrications still pose a challenge. In the macromonomer route for the synthesis of dendronized polymers, the preferred route due to complete and uniform dendron functionalization, high degrees of polymerization are difficult to achieve due to steric crowding. This limitation was overcome by incorporating linkers between the polymerizable group (norbornene) and the poly(amide)-based dendrons. By increasing the length of the linker, the rate of polymerization increased. The synthesis of block copolymers using non-living polymerization methods often requires the copolymerization of monomers by different polymerization mechanisms. This methodology is hampered by non-quantitative conversions of the precursor polymer into the required macroinitiator. This limitation was overcome by using a bifunctional initiator. Poly(norbornene)-block -poly(lactic acid)s were synthesized using a ruthenium initiator for the ring-opening metathesis polymerization (ROMP) and a hydroxy group to initiate the ring-opening polymerization (ROP) of L-lactide. This method opens up new routes for the creation of functional block copolymers that are created by a combination of ROMP and ROP. Finally, potential strategies towards the synthesis of complex polymer architectures for biomaterials using the methodologies developed in this thesis are described. Firstly, the synthesis of orthogonally functionalizable dendronized polymers for targeted drug-delivery is proposed. Second, studies to establish the relationship between architectures and properties for biological applications

  10. [Research progress on application of carbon nanotubes in bone tissue engineering scaffold].

    PubMed

    Yao, Mengzhu; Sheng, Xiaoxia; Lin, Jun; Gao, Jianqing

    2016-03-01

    Carbon nanotubes possess excellent mechanical and electrical properties and demonstrate broad application prospects in medical fields. Carbon nanotubes are composed of inorganic materials, natural biodegradable polymer or synthetic biodegradable polymer. The composite bone tissue engineering scaffolds are constructed by particle-hole method, lyophilization, microsphere aggregation method, electrostatic spinning or three-dimensional printing. Composite scaffolds overcome the shortcomings of single material and have good biocompatibility, osteoconduction and osteoinduction. With the study of surface chemistry, toxicology, and biocompatibility, a degradable "human-friendly" carbon nanotubes composite bone tissue scaffold will be available; and under the drive of new fabrication techniques, the clinical application of carbon nanotubes composite bone tissue engineering scaffolds will be better developed. PMID:27273990

  11. Hydrogel/bioactive glass composites for bone regeneration applications: synthesis and characterisation.

    PubMed

    Killion, John A; Kehoe, Sharon; Geever, Luke M; Devine, Declan M; Sheehan, Eoin; Boyd, Daniel; Higginbotham, Clement L

    2013-10-01

    Due to the deficiencies of current commercially available biological bone grafts, alternative bone graft substitutes have come to the forefront of tissue engineering in recent times. The main challenge for scientists in manufacturing bone graft substitutes is to obtain a scaffold that has sufficient mechanical strength and bioactive properties to promote formation of new tissue. The ability to synthesise hydrogel based composite scaffolds using photopolymerisation has been demonstrated in this study. The prepared hydrogel based composites were characterised using techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectrometry (EDX), rheological studies and compression testing. In addition, gel fraction, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), porosity and swelling studies of the composites were carried out. It was found that these novel hydrogel bioglass composite formulations did not display the inherent brittleness that is typically associated with bioactive glass based bone graft materials and exhibited enhanced biomechanical properties compared to the polyethylene glycol hydrogel scaffolds along. Together, the combination of enhanced mechanical properties and the deposition of apatite on the surface of these hydrogel based composites make them an ideal candidate as bone graft substitutes in cancellous bone defects or low load bearing applications. PMID:23910334

  12. Application of Ultrasonic Bone Curette in Endoscopic Endonasal Skull Base Surgery: Technical Note

    PubMed Central

    Rastelli, Milton M.; Pinheiro-Neto, Carlos D.; Fernandez-Miranda, Juan C.; Wang, Eric W.; Snyderman, Carl H.; Gardner, Paul A.

    2014-01-01

    Background Endoscopic endonasal surgery (EES) of the skull base often requires extensive bone work in proximity to critical neurovascular structures. Objective To demonstrate the application of an ultrasonic bone curette during EES. Methods Ten patients with skull base lesions underwent EES from September 2011 to April 2012 at the University of Pittsburgh Medical Center. Most of the bone work was done with high-speed drill and rongeurs. The ultrasonic curette was used to remove specific structures. Results All the patients were submitted to fully endoscopic endonasal procedures and had critical bony structures removed with the ultrasonic bone curette. Two patients with degenerative spine diseases underwent odontoid process removal. Five patients with clival and petroclival tumors underwent posterior clinoid removal. Two patients with anterior fossa tumors underwent crista galli removal. One patient underwent unilateral optic nerve decompression. No mechanical or heat injury resulted from the ultrasonic curette. The surrounding neurovascular structures and soft tissue were preserved in all cases. Conclusion In selected EES, the ultrasonic bone curette was successfully used to remove loose pieces of bone in narrow corridors, adjacent to neurovascular structures, and it has advantages to high-speed drills in these specific situations. PMID:24719795

  13. High Potential for Using DNA from Ancient Herring Bones to Inform Modern Fisheries Management and Conservation

    PubMed Central

    Speller, Camilla F.; Hauser, Lorenz; Lepofsky, Dana; Moore, Jason; Rodrigues, Antonia T.; Moss, Madonna L.; McKechnie, Iain; Yang, Dongya Y.

    2012-01-01

    Pacific herring (Clupea pallasi) are an abundant and important component of the coastal ecosystems for the west coast of North America. Current Canadian federal herring management assumes five regional herring populations in British Columbia with a high degree of exchange between units, and few distinct local populations within them. Indigenous traditional knowledge and historic sources, however, suggest that locally adapted, distinct regional herring populations may have been more prevalent in the past. Within the last century, the combined effects of commercial fishing and other anthropogenic factors have resulted in severe declines of herring populations, with contemporary populations potentially reflecting only the remnants of a previously more abundant and genetically diverse metapopulation. Through the analysis of 85 archaeological herring bones, this study attempted to reconstruct the genetic diversity and population structure of ancient herring populations using three different marker systems (mitochondrial DNA (mtDNA), microsatellites and SNPs). A high success rate (91%) of DNA recovery was obtained from the extremely small herring bone samples (often <10 mg). The ancient herring mtDNA revealed high haplotype diversity comparable to modern populations, although population discrimination was not possible due to the limited power of the mtDNA marker. Ancient microsatellite diversity was also similar to modern samples, but the data quality was compromised by large allele drop-out and stuttering. In contrast, SNPs were found to have low error rates with no evidence for deviations from Hardy-Weinberg equilibrium, and simulations indicated high power to detect genetic differentiation if loci under selection are used. This study demonstrates that SNPs may be the most effective and feasible approach to survey genetic population structure in ancient remains, and further efforts should be made to screen for high differentiation markers.This study provides the much

  14. CD45 fraction bone marrow cells as potential delivery vehicles for genetically corrected dystrophin loci.

    PubMed

    Kapsa, R M I; Wong, S H A; Bertoncello, I; Quigley, A F; Williams, B; Sells, K; Marotta, R; Kita, M; Simmons, P; Byrne, E; Kornberg, A J

    2002-10-01

    Targeted correction of mutations in muscle can be delivered by direct i.m. injection of corrective DNA to the dystrophic muscle or by autologous injection of cells that have been genetically corrected after isolation from the individual with the dystrophic muscle. The successful application of chimeraplasty and short fragment homologous replacement to correct the exon 23 nonsense mdx transition at the mouse dys locus has opened up the possibility that with further development, targeted gene correction may have some future application for the treatment of muscular dystrophies. In vitro, application of targeted gene correction at the mdx dys locus results in better correction efficiencies than when applied directly to dystrophic muscle. This suggests that at least for the time being, a strategy involving ex vivo correction may be advantageous over a direct approach for delivery of gene correction to dystrophic muscle. This, particularly in view of recent developments indicating that bone-marrow-derived cells are able to systemically remodel dystrophic muscle, whilst penetration of DNA introduced to muscle is limited to individually injected muscles. Application of targeted gene correction to Duchenne dystrophy needs to account for the fact that about 65% of Duchenne muscular dystrophy cases involve large frame-shift deletion of gene sequence at the dys locus. Traditionally, whilst targeted gene correction is able to restore point mutations entirely, it remains to be seen as to whether a strategy for the 'correction' of frame shift deletions may be engineered successfully. This communication discusses the possibility of applying targeted gene correction to dystrophic muscle in Duchenne dystrophy. PMID:12206798

  15. Potential of bone marrow mesenchymal stem cells in management of Alzheimer's disease in female rats.

    PubMed

    Salem, Ahmed M; Ahmed, Hanaa H; Atta, Hazem M; Ghazy, Mohamed A; Aglan, Hadeer A

    2014-12-01

    Alzheimer's disease (AD) has been called the disease of the century with significant clinical and socioeconomic impacts. Pharmacological treatment has limited efficacy and only provides symptomatic relief without long-term cure. Accordingly, there is an urgent need to develop novel and effective medications for AD. Stem cell-based therapy is a promising approach to handling neurodegenerative diseases. Therefore, the current study aimed to explore the possible therapeutic role of single intravenous injection of bone marrow derived mesenchymal stem cells (BM-MSCs) after 4 months in management of AD in the experimental model. The work also extended to compare the therapeutic potential of BM-MSCs with 2 conventional therapies of AD; rivastigmine and cerebrolysin administered daily. BM-MSCs were able to home at the injured brains and produced significant increases in the number of positive cells for choline acetyltransferase (ChAT) and survivin expression, as well as selective AD indicator-1 (seladin-1) and nestin gene expression. Histopathological examination indicated that BM-MSCs could remove beta-amyloid plaques from hippocampus. Significant improvement in these biomarkers was similar to or better sometimes than the reference drugs, clearly showing the potential therapeutic role of BM-MSCs against AD through their anti-apoptotic, neurogenic and immunomodulatory properties. PMID:25044885

  16. The NTD Nanoscope: potential applications and implementations

    PubMed Central

    2011-01-01

    Background Nanopore transduction detection (NTD) offers prospects for a number of highly sensitive and discriminative applications, including: (i) single nucleotide polymorphism (SNP) detection; (ii) targeted DNA re-sequencing; (iii) protein isoform assaying; and (iv) biosensing via antibody or aptamer coupled molecules. Nanopore event transduction involves single-molecule biophysics, engineered information flows, and nanopore cheminformatics. The NTD Nanoscope has seen limited use in the scientific community, however, due to lack of information about potential applications, and lack of availability for the device itself. Meta Logos Inc. is developing both pre-packaged device platforms and component-level (unassembled) kit platforms (the latter described here). In both cases a lipid bi-layer workstation is first established, then augmentations and operational protocols are provided to have a nanopore transduction detector. In this paper we provide an overview of the NTD Nanoscope applications and implementations. The NTD Nanoscope Kit, in particular, is a component-level reproduction of the standard NTD device used in previous research papers. Results The NTD Nanoscope method is shown to functionalize a single nanopore with a channel current modulator that is designed to transduce events, such as binding to a specific target. To expedite set-up in new lab settings, the calibration and troubleshooting for the NTD Nanoscope kit components and signal processing software, the NTD Nanoscope Kit, is designed to include a set of test buffers and control molecules based on experiments described in previous NTD papers (the model systems briefly described in what follows). The description of the Server-interfacing for advanced signal processing support is also briefly mentioned. Conclusions SNP assaying, SNP discovery, DNA sequencing and RNA-seq methods are typically limited by the accuracy of the error rate of the enzymes involved, such as methods involving the polymerase

  17. Bone morphogenetic protein

    SciTech Connect

    Xiao Yongtao; Xiang Lixin; Shao Jianzhong

    2007-10-26

    Bone morphogenetic proteins (BMPs) are multi-functional growth factors belonging to the transforming growth factor-beta superfamily. It has been demonstrated that BMPs had been involved in the regulation of cell proliferation, survival, differentiation and apoptosis. However, their hallmark ability is that play a pivotal role in inducing bone, cartilage, ligament, and tendon formation at both heterotopic and orthotopic sites. In this review, we mainly concentrate on BMP structure, function, molecular signaling and potential medical application.

  18. Potential applications of insect symbionts in biotechnology.

    PubMed

    Berasategui, Aileen; Shukla, Shantanu; Salem, Hassan; Kaltenpoth, Martin

    2016-02-01

    Symbiotic interactions between insects and microorganisms are widespread in nature and are often the source of ecological innovations. In addition to supplementing their host with essential nutrients, microbial symbionts can produce enzymes that help degrade their food source as well as small molecules that defend against pathogens, parasites, and predators. As such, the study of insect ecology and symbiosis represents an important source of chemical compounds and enzymes with potential biotechnological value. In addition, the knowledge on insect symbiosis can provide novel avenues for the control of agricultural pest insects and vectors of human diseases, through targeted manipulation of the symbionts or the host-symbiont associations. Here, we discuss different insect-microbe interactions that can be exploited for insect pest and human disease control, as well as in human medicine and industrial processes. Our aim is to raise awareness that insect symbionts can be interesting sources of biotechnological applications and that knowledge on insect ecology can guide targeted efforts to discover microorganisms of applied value. PMID:26659224

  19. Vehicle bridge interaction dynamics and potential applications

    NASA Astrophysics Data System (ADS)

    Yang, Y. B.; Lin, C. W.

    2005-06-01

    The dynamic interaction between a moving vehicle and the sustaining bridge is studied. By the method of modal superposition, closed-form solutions are obtained for the vertical responses of both the bridge and moving vehicle, assuming the vehicle/bridge mass ratio to be small. For both the bridge and vehicle responses, it is confirmed that rather accurate solutions can be obtained by considering only the first mode. The displacement, velocity, and acceleration of the bridge are governed at different extents by two sets of frequencies, i.e., the driving frequency of the vehicle and natural frequencies of the bridge. From the spectrum for the bridge displacement, the vehicle speeds can be shown to be associated with some low-frequency pikes. On the other hand, the vehicle responses are governed by five distinct frequencies that appear as driving frequencies, vehicle frequency, and bridge frequencies with shift. From the vehicle's acceleration spectrum, the first bridge frequency (with shift) is shown to have rather high visibility and can be easily identified. The effects of damping of the vehicle and bridge are evaluated in the numerical studies. Potential applications of the present results, as well as further researches required, are also indicated in the paper.

  20. Application potential of rechargeable lithium batteries

    SciTech Connect

    Hunger, H.F.; Bramhall, P.J.

    1983-10-01

    Rechargeable lithium cells with Cr /SUB 0.5/ V/sub 0/ /sub 5/S/sub 2/ and MoO/sub 3/ cathodes were investigated in the temperature range of -30/sup 0/C to +25/sup 0/C. The electrolyte was 1.5M LiAsF/sub 6/ in 2-methyl tetrahydrofuran with tetrahydrofuran (50:50 V percent). Current densities and capacities as a function of temperature, cathode utilization efficiencies versus cycle life, and shelf lives were determined. The state of charge could be related to open circuit voltages after partial discharge. The potential of the system for communication applications is discussed. Recent advances in rechargeable lithium batteries were mainly due to the discovery of stable, cyclic ether electrolyte solvents (1) and to the use of rechargeable cathode materials (2). The practical usefulness of rechargeable lithium cells with Cr /SUB 0.5/ V /SUB 0.5/ S/sub 2/ and MoO/sub 3/ cathodes was investigated in the temperature range of -30/sup 0/C to +25/sup 0/C. The electrolyte was mainly 1.5M LiAsF/sub 6/ in 2-methyl tetrahydrofuran with tetrahydrofuran (50:50 V percent). The two cathode materials were chosen because Cr /SUB 0.5/ V /SUB 0.5/ S/sub 2/ resembles TiS/sub 2/ in capacity and cycling behavior and MoO/sub 3/ is a low cost cathode material of interest.

  1. Textural entropy as a potential feature for quantitative assessment of jaw bone healing process

    PubMed Central

    Kozakiewicz, Marcin; Materka, Andrzej

    2015-01-01

    Introduction The aim of the study was to propose and evaluate textural entropy as a parameter for bone healing assessment. Material and methods One hundred and twenty radiographs with loss of bone architecture were investigated (a bone defect was circumscribed – ROI DEF). A reference region (ROI REF) of the same surface area as the ROI DEF was placed in a field distant from the defect, where a normal, trabecular pattern of bone structure was well visualized. Data of three time points were investigated: T0 – immediately after the surgical procedure, T1 – 3 months post-op, and T2 – 12 months post-op. Results Textural entropy as a parameter describing bone structure regeneration was selected based on Fisher coefficient (F) evaluation. F was highest in T0 (3.4) and was decreasing later in T1 (1.7) and T2 (1.0 – means final lack of difference in the structure to reference bone). Textural entropy is a measure of structure disarrangement which in a bone defect region attains minimal value due to structural homogeneity, i.e. low complexity of the texture. The calculated parameter in the investigated material revealed a gradual increase inside the bone defect (p < 0.05), i.e. increase of complexity in a time-dependent manner starting from immediate post-op (T0 = 2.51; T1 = 2.68) up to most complex 1 year post-operational (T2 = 2.73), reaching the reference level of a normal bone. Conclusions Textural entropy may be useful for computer assisted evaluation of bone regeneration process. The complexity of the texture corresponds to mature trabecular bone formation. PMID:25861292

  2. Application of Laser-Induced Bone Therapy by Carbon Dioxide Laser Irradiation in Implant Therapy

    PubMed Central

    Naka, Takahiro; Yokose, Satoshi

    2012-01-01

    This study evaluated the application of laser-induced bone therapy (LIBT) to reduce implant healing time in rat tibia. Twenty 10-week-old female Sprague-Dawlay rats were used. The rats received laser irradiation (laser group) or sham operation (control group) on either side of the tibia. Five days after invasion, titanium implants were inserted in proximal tibia. Five, 10, and 20 days after implant placement, tibiae were collected. After taking micro-CT and performing a torque test, the tibiae were decalcified and 8-μm-thick sections were prepared. Specimens were stained with hematoxylin and eosin. Results. Micro-CT images, removal torque values, and histomorphometric analysis data demonstrated a significantly accelerated bone formation in the laser group earlier in the healing process. Conclusion. The use of laser irradiation was effective in promoting bone formation and acquiring osseointegration of titanium implants inserted in rat tibia. LIBT may be suitable for use in implant therapy. PMID:22505900

  3. Bone Regeneration Potential of Stem Cells Derived from Periodontal Ligament or Gingival Tissue Sources Encapsulated in RGD-Modified Alginate Scaffold

    PubMed Central

    Chen, Chider; Xu, Xingtian; Akiyama, Kentaro; Ansari, Sahar; Zadeh, Homayoun H.; Shi, Songtao

    2014-01-01

    Mesenchymal stem cells (MSCs) provide an advantageous alternative therapeutic option for bone regeneration in comparison to current treatment modalities. However, delivering MSCs to the defect site while maintaining a high MSC survival rate is still a critical challenge in MSC-mediated bone regeneration. Here, we tested the bone regeneration capacity of periodontal ligament stem cells (PDLSCs) and gingival mesenchymal stem cells (GMSCs) encapsulated in a novel RGD- (arginine-glycine-aspartic acid tripeptide) coupled alginate microencapsulation system in vitro and in vivo. Five-millimeter-diameter critical-size calvarial defects were created in immunocompromised mice and PDLSCs and GMSCs encapsulated in RGD-modified alginate microspheres were transplanted into the defect sites. New bone formation was assessed using microcomputed tomography and histological analyses 8 weeks after transplantation. Results confirmed that our microencapsulation system significantly enhanced MSC viability and osteogenic differentiation in vitro compared with non-RGD-containing alginate hydrogel microspheres with larger diameters. Results confirmed that PDLSCs were able to repair the calvarial defects by promoting the formation of mineralized tissue, while GMSCs showed significantly lower osteogenic differentiation capability. Further, results revealed that RGD-coupled alginate scaffold facilitated the differentiation of oral MSCs toward an osteoblast lineage in vitro and in vivo, as assessed by expression of osteogenic markers Runx2, ALP, and osteocalcin. In conclusion, these results for the first time demonstrated that MSCs derived from orofacial tissue encapsulated in RGD-modified alginate scaffold show promise for craniofacial bone regeneration. This treatment modality has many potential dental and orthopedic applications. PMID:24070211

  4. Bone regeneration potential of stem cells derived from periodontal ligament or gingival tissue sources encapsulated in RGD-modified alginate scaffold.

    PubMed

    Moshaverinia, Alireza; Chen, Chider; Xu, Xingtian; Akiyama, Kentaro; Ansari, Sahar; Zadeh, Homayoun H; Shi, Songtao

    2014-02-01

    Mesenchymal stem cells (MSCs) provide an advantageous alternative therapeutic option for bone regeneration in comparison to current treatment modalities. However, delivering MSCs to the defect site while maintaining a high MSC survival rate is still a critical challenge in MSC-mediated bone regeneration. Here, we tested the bone regeneration capacity of periodontal ligament stem cells (PDLSCs) and gingival mesenchymal stem cells (GMSCs) encapsulated in a novel RGD- (arginine-glycine-aspartic acid tripeptide) coupled alginate microencapsulation system in vitro and in vivo. Five-millimeter-diameter critical-size calvarial defects were created in immunocompromised mice and PDLSCs and GMSCs encapsulated in RGD-modified alginate microspheres were transplanted into the defect sites. New bone formation was assessed using microcomputed tomography and histological analyses 8 weeks after transplantation. Results confirmed that our microencapsulation system significantly enhanced MSC viability and osteogenic differentiation in vitro compared with non-RGD-containing alginate hydrogel microspheres with larger diameters. Results confirmed that PDLSCs were able to repair the calvarial defects by promoting the formation of mineralized tissue, while GMSCs showed significantly lower osteogenic differentiation capability. Further, results revealed that RGD-coupled alginate scaffold facilitated the differentiation of oral MSCs toward an osteoblast lineage in vitro and in vivo, as assessed by expression of osteogenic markers Runx2, ALP, and osteocalcin. In conclusion, these results for the first time demonstrated that MSCs derived from orofacial tissue encapsulated in RGD-modified alginate scaffold show promise for craniofacial bone regeneration. This treatment modality has many potential dental and orthopedic applications. PMID:24070211

  5. Abnormal bone marrow distribution following unsuccessful hip replacement: a potential confusion on white cell scanning.

    PubMed

    Cunningham, D A

    1991-01-01

    A case is presented in which a grossly abnormal distribution of bone marrow following failed hip replacement would have led to the false diagnosis of osteomyelitis. The value of combining bone marrow scanning with indium white cell scanning in possible osteomyelitis is emphasised. PMID:2019282

  6. Bioactive polymeric-ceramic hybrid 3D scaffold for application in bone tissue regeneration.

    PubMed

    Torres, A L; Gaspar, V M; Serra, I R; Diogo, G S; Fradique, R; Silva, A P; Correia, I J

    2013-10-01

    The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D β-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric-bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration. PMID:23910366

  7. In vivo corrosion behavior of Mg-Mn-Zn alloy for bone implant application.

    PubMed

    Xu, Liping; Yu, Guoning; Zhang, Erlin; Pan, Feng; Yang, Ke

    2007-12-01

    Magnesium alloy has been implanted in rats to investigate the in vivo degradation behavior of magnesium for bone implant application. After 9 weeks postoperation, 100% implants were fixed and no inflammation was observed. Histological analysis showed new bone was formed around magnesium implant and no difference was found in the histological microstructure of the new bone and the cortical bone. A degradation or reaction layer, which was mainly composed of Ca, P, O, and Mg, was formed on the surface of magnesium alloy implants. High Ca content in the degradation layer displayed that magnesium could promote the deposition of Ca. Residual area calculation has showed that 10-17% magnesium alloy implant has been degraded in vivo. Compared with that of the controlled rats, no increase in serum magnesium and no disorder of kidney were observed after 15 weeks postoperation. After 18 weeks postoperation, 100% magnesium implants were fixed and no inflammation was observed. About 54% magnesium implant has degraded in vivo. Element analysis showed that Zn and Mn in Mg-Mn-Zn alloy distributed homogeneously in the residual magnesium implant, the degradation layer, and the surrounding bone tissue after 18 weeks implantation, indicating that Zn and Mn elements were easily absorbed by bioenvironment. PMID:17549695

  8. Bisphosphonate-Related Osteonecrosis of the Jaw Bone: Radiological Pattern and the Potential Role of CBCT in Early Diagnosis

    PubMed Central

    Agbaje, Jimoh Olubanwo; Jacobs, Reinhilde; Verhaeghe, Vicky; Velde, Filip Vande; Vinckier, Frans

    2010-01-01

    ABSTRACT Objectives To systematize the clinico-radiological symptoms and course of bisphosphonate-related osteonecrosis of jaw bone and toevaluate the diagnostic potential of various radiological techniques to detect mild osteonecrosis in each stage of the disease. Material and Methods The sample consisted of 22 patients previously diagnosed with extraoral malignant disease. Diagnosis was based on a clinical examination in conjunction to digital panoramic radiography and cone beam computed tomography (CBCT). Two dentomaxillofacial radiologists reviewed all images. Results Twenty patients showed mandibular involvement clinically, while two others had a maxillary involvement. Four stages of the disease were proposed based on the clinico-radiological findings. Subclinical cortical and lamina dura thickening was detected with only three-dimensional CBCT and periapical images, while ulceration and cortical bone thickening was detected only by three-dimensional CBCT. Mixed sclerotic, lytic bone destruction involving alveolar and basal bone with or without encroachment on the mandibular canal, pathological mandibular fractures were detected by two-dimensional panoramic and three-dimensional CBCT images. Other findings are non healing extraction sockets, periapical radiolucencies, osteolysis, sequestra, oroantral fistula, and periosteal new bone formation. Conclusions The present study showed that bisphosphonate-related osteonecrosis of jaw bone occurs in four distinct clinico-radiological stages. For mild cases, panoramic image diagnosis was much less obvious, whereas cone beam computed tomography was able to fully characterise the bony lesions and describe their extent and involvement of neighbouring structures in all cases. Thus cone beam computed tomography might better contribute to the prevention of bisphosphonate-related osteonecrosis of jaw bone as well to the disease management. PMID:24421968

  9. Enzymatically synthesized inorganic polymers as morphogenetically active bone scaffolds: application in regenerative medicine.

    PubMed

    Wang, Xiaohong; Schröder, Heinz C; Müller, Werner E G

    2014-01-01

    In recent years a paradigm shift in understanding of human bone formation has occurred that starts to change current concepts in tissue engineering of bone and cartilage. New discoveries revealed that fundamental steps in biomineralization are enzyme driven, not only during hydroxyapatite deposition, but also during initial bioseed formation, involving the transient deposition and subsequent transformation of calcium carbonate to calcium phosphate mineral. The principal enzymes mediating these reactions, carbonic anhydrase and alkaline phosphatase, open novel targets for pharmacological intervention of bone diseases like osteoporosis, by applying compounds acting as potential activators of these enzymes. It is expected that these new findings will give an innovation boost for the development of scaffolds for bone repair and reconstruction, which began with the use of bioinert materials, followed by bioactive materials and now leading to functional regenerative tissue units. These new developments have become possible with the discovery of the morphogenic activity of bioinorganic polymers, biocalcit, bio-polyphosphate and biosilica that are formed by a biogenic, enzymatic mechanism, a driving force along with the development of novel rapid-prototyping three-dimensional (3D) printing methods and bioprinting (3D cell printing) techniques that may allow a fabrication of customized implants for patients suffering in bone diseases in the future. PMID:25376489

  10. Two applications of potential vorticity thinking

    NASA Technical Reports Server (NTRS)

    Robinson, Walter A.

    1987-01-01

    The phenomena of dissipative destabilization of external Rossby waves and the acceleration of the zonal mean jet during baroclinic life cycles are described in terms of potential vorticity. The main principle of the potential temperature variations at rigid boundaries have the same effect on the interior flow as do sheets of potential vorticity located just within the boundaries. It is noted that the potential vorticity theory is useful for understanding the dynamical behavior of meterological phenomena.

  11. Morphological features of the macerated cranial bones registered by the 3D vision system for potential use in forensic anthropology.

    PubMed

    Skrzat, Janusz; Sioma, Andrzej; Kozerska, Magdalena

    2013-01-01

    In this paper we present potential usage of the 3D vision system for registering features of the macerated cranial bones. Applied 3D vision system collects height profiles of the object surface and from that data builds a three-dimensional image of the surface. This method appeared to be accurate enough to capture anatomical details of the macerated bones. With the aid of the 3D vision system we generated images of the surface of the human calvaria which was used for testing the system. Performed reconstruction visualized the imprints of the dural vascular system, cranial sutures, and the three-layer structure of the cranial bones observed in the cross-section. We figure out that the 3D vision system may deliver data which can enhance estimation of sex from the osteological material. PMID:24858457

  12. Bone-Targeted Acid-Sensitive Doxorubicin Conjugate Micelles as Potential Osteosarcoma Therapeutics

    PubMed Central

    2015-01-01

    Osteosarcoma is a malignancy of the bone that primarily affects adolescents. Current treatments retain mortality rates, which are higher than average cancer mortality rates for the adolescent age group. We designed a micellar delivery system with the aim to increase drug accumulation in the tumor and potentially reduce side effects associated with chemotherapy. The design features are the use of the hydrophilic d-aspartic acid octapeptide as both the effective targeting agent as well as the hydrophilic micelle corona. Micelle stabilization was accomplished by binding of model drug (doxorubicin) via an acid-sensitive hydrazone bond and incorporating one to four 11-aminoundecanoic acid (AUA) moieties to manipulate the hydrophobic/hydrophilic ratio. Four micelle-forming unimers have been synthesized and their self-assembly into micelles was evaluated. Size of the micelles could be modified by changing the architecture of the unimers from linear to branched. The stability of the micelles increased with increasing content of AUA moieties. Adsorption of all micelles to hydroxyapatite occurred rapidly. Doxorubicin release occurred at pH 5.5, whereas no release was detected at pH 7.4. Cytotoxicity toward human osteosarcoma Saos-2 cells correlated with drug release data. PMID:25291150

  13. Influence of age on rat bone-marrow mesenchymal stem cells potential

    PubMed Central

    Fafián-Labora, J.; Fernández-Pernas, P.; Fuentes, I.; De Toro, J.; Oreiro, N.; Sangiao-Alvarellos, S.; Mateos, J.; Arufe, M.C.

    2015-01-01

    Mesenchymal stem cells promising role in cell-based therapies and tissue engineering appears to be limited due to a decline of their regenerative potential with increasing donor age. Six age groups from bone marrow mesenchymal stem cells of Wistar rats were studied (newborn, infant, young, pre-pubertal, pubertal and adult). Quantitative proteomic assay was performance by iTRAQ using an 8-plex iTRAQ labeling and the proteins differentially expressed were grouped in pluripotency, proliferative and metabolism processes. Proliferation makers, CD117 and Ki67 were measure by flow cytometry assay. Real time polymerase chain reaction analysis of pluripotency markers Rex1, Oct4, Sox2 and Nanog were done. Biological differentiation was realized using specific mediums for 14 days to induce osteogenesis, adipogenesis or chondrogenesis and immunostain analysis of differentiated cell resulting were done. Enzimoimmunoassay analysis of several enzymes as L-lactate dehydrogenase and glucose-6-phosphate isomerase were also done to validate iTRAQ data. Taking together these results indicate for the first time that mesenchymal stem cells have significant differences in their proliferative, pluripotency and metabolism profiles and those differences are age depending. PMID:26581954

  14. Bone-targeted acid-sensitive doxorubicin conjugate micelles as potential osteosarcoma therapeutics.

    PubMed

    Low, Stewart A; Yang, Jiyuan; Kopeček, Jindřich

    2014-11-19

    Osteosarcoma is a malignancy of the bone that primarily affects adolescents. Current treatments retain mortality rates, which are higher than average cancer mortality rates for the adolescent age group. We designed a micellar delivery system with the aim to increase drug accumulation in the tumor and potentially reduce side effects associated with chemotherapy. The design features are the use of the hydrophilic D-aspartic acid octapeptide as both the effective targeting agent as well as the hydrophilic micelle corona. Micelle stabilization was accomplished by binding of model drug (doxorubicin) via an acid-sensitive hydrazone bond and incorporating one to four 11-aminoundecanoic acid (AUA) moieties to manipulate the hydrophobic/hydrophilic ratio. Four micelle-forming unimers have been synthesized and their self-assembly into micelles was evaluated. Size of the micelles could be modified by changing the architecture of the unimers from linear to branched. The stability of the micelles increased with increasing content of AUA moieties. Adsorption of all micelles to hydroxyapatite occurred rapidly. Doxorubicin release occurred at pH 5.5, whereas no release was detected at pH 7.4. Cytotoxicity toward human osteosarcoma Saos-2 cells correlated with drug release data. PMID:25291150

  15. Comparative study of the chondrogenic potential of human bone marrow stromal cells, neonatal chondrocytes and adult chondrocytes

    SciTech Connect

    Saha, Sushmita; Kirkham, Jennifer; Wood, David; Curran, Stephen; Yang, Xuebin

    2010-10-22

    Research highlights: {yields} This study has characterised three different cell types under conditions similar to those used for autologous chondrocyte implantation (ACI) for applications in cartilage repair/regeneration. {yields} Compared for the first time the chondrogenic potential of neonatal chondrocytes with human bone marrow stromal cells (HBMSCs) and adult chondrocytes. {yields} Demonstrated that adult chondrocytes hold greatest potential for use in ACI based on their higher proliferation rates, lower alkaline phosphatise activity and enhanced expression of chondrogenic genes. {yields} Demonstrated the need for chondroinduction as a necessary pre-requisite to efficient chondrogenesis in vitro and, by extrapolation, for cell based therapy (e.g. ACI or cartilage tissue engineering). -- Abstract: Cartilage tissue engineering is still a major clinical challenge with optimisation of a suitable source of cells for cartilage repair/regeneration not yet fully addressed. The aims of this study were to compare and contrast the differences in chondrogenic behaviour between human bone marrow stromal cells (HBMSCs), human neonatal and adult chondrocytes to further our understanding of chondroinduction relative to cell maturity and to identify factors that promote chondrogenesis and maintain functional homoeostasis. Cells were cultured in monolayer in either chondrogenic or basal medium, recapitulating procedures used in existing clinical procedures for cell-based therapies. Cell doubling time, morphology and alkaline phosphatase specific activity (ALPSA) were determined at different time points. Expression of chondrogenic markers (SOX9, ACAN and COL2A1) was compared via real time polymerase chain reaction. Amongst the three cell types studied, HBMSCs had the highest ALPSA in basal culture and lowest ALPSA in chondrogenic media. Neonatal chondrocytes were the most proliferative and adult chondrocytes had the lowest ALPSA in basal media. Gene expression analysis revealed

  16. Sustained release of bone morphogenetic protein 2 via coacervate improves the osteogenic potential of muscle-derived stem cells.

    PubMed

    Li, Hongshuai; Johnson, Noah Ray; Usas, Arvydas; Lu, Aiping; Poddar, Minakshi; Wang, Yadong; Huard, Johnny

    2013-09-01

    Muscle-derived stem cells (MDSCs) isolated from mouse skeletal muscle by a modified preplate technique exhibit long-term proliferation, high self-renewal, and multipotent differentiation capabilities in vitro. MDSCs retrovirally transduced to express bone morphogenetic proteins (BMPs) can differentiate into osteocytes and chondrocytes and enhance bone and articular cartilage repair in vivo, a feature that is not observed with nontransduced MDSCs. These results emphasize that MDSCs require prolonged exposure to BMPs to undergo osteogenic and chondrogenic differentiation. A sustained BMP protein delivery approach provides a viable and potentially more clinically translatable alternative to genetic manipulation of the cells. A unique growth factor delivery platform comprised of native heparin and a synthetic polycation, poly(ethylene argininylaspartate diglyceride) (PEAD), was used to bind, protect, and sustain the release of bone morphogenetic protein-2 (BMP2) in a temporally and spatially controlled manner. Prolonged exposure to BMP2 released by the PEAD:heparin delivery system promoted the differentiation of MDSCs to an osteogenic lineage in vitro and induced the formation of viable bone at an ectopic site in vivo. This new strategy represents an alternative approach for bone repair mediated by MDSCs while bypassing the need for gene therapy. PMID:23884640

  17. Bone-targeted delivery of nanodiamond-based drug carriers conjugated with alendronate for potential osteoporosis treatment.

    PubMed

    Ryu, Tae-Kyung; Kang, Rae-Hyoung; Jeong, Ki-Young; Jun, Dae-Ryong; Koh, Jung-Min; Kim, Doyun; Bae, Soo Kyung; Choi, Sung-Wook

    2016-06-28

    This paper describes the design of alendronate-conjugated nanodiamonds (Alen-NDs) and evaluation of their feasibility for bone-targeted delivery. Alen-NDs exhibited a high affinity to hydroxyapatite (HAp, the mineral component of bone) due to the presence of Alen. Unlike NDs (without Alen), Alen-NDs were preferentially taken up by MC3T3-E1 osteoblast-like cells, compared to NIH3T3 and HepG2 cells, suggesting their cellular specificity. In addition, NDs itself increased ALP activity of MC3T3-E1 cells, compared to control group (osteogenic medium) and Alen-NDs exhibited more enhanced ALP activity. In addition, an in vivo study revealed that Alen-NDs effectively accumulated in bone tissues after intravenous tail vein injection. These results confirm the superior properties of Alen-NDs with advantages of high HAp affinity, specific uptake for MC3T3-E1 cells, positive synergistic effect for ALP activity, and in vivo bone targeting ability. The Alen-NDs can potentially be employed for osteoporosis treatment by delivering both NDs and Alen to bone tissue. PMID:27094604

  18. Strontium- and magnesium-enriched biomimetic β-TCP macrospheres with potential for bone tissue morphogenesis.

    PubMed

    Chou, J; Valenzuela, S M; Santos, J; Bishop, D; Milthorpe, B; Green, D W; Otsuka, M; Ben-Nissan, B

    2014-10-01

    During the last two decades, biogenic mineral ions have become important additives in treatments for bone regeneration and repair. Prominent among these is strontium, which is a potent suppressor of osteoclast bone resorption. Another is magnesium, which has a key influence in mineralization processes. The shells of benthic foraminiferans, hydrothermally converted into β-TCP, have been shown to effectively release a number of bone-promoting drugs at clinically relevant levels. In this study we characterized the effects of converted foraminiferan calcium dissolution and the concomitant release profile of intrinsic strontium and magnesium. We tested the effects of strontium- and magnesium-enriched macrospheres on human osteoblast (SaOS-2) and monocytoid (U937) cell lines, which can be induced to express equivalent phagocytic activities to osteoclasts. On dissolution in a biomimetic physiological solution, the macrospheres released biologically significant quantities of calcium and phosphate ions in the first 18 days. At 3 days, during which biogenic mineral ions are released, the number of U937 osteoclast-like monocyte cells decreased, while 4 days later the osteoblast cell number increased. These results show that strontium and magnesium naturally enriched macrospheres are capable of altering the metabolic activities of the cells regulating bone homeostasis. These unique macrospheres are natural origin bone void filler particles that resorb, and release physiologically significant levels of incorporated strontium, magnesium and calcium, which together make a uniquely multifunctional in situ remedy for bone regeneration and repair and the treatment of bone-wasting diseases. PMID:22837177

  19. Bone cement/layered double hydroxide nanocomposites as potential biomaterials for joint implant.

    PubMed

    Kapusetti, Govinda; Misra, Nira; Singh, Vakil; Kushwaha, R K; Maiti, Pralay

    2012-12-01

    Poly(methyl methacrylate)-based bone cement and layered double hydroxide (LDH) nanocomposites have been used as a grouting material for total joint arthroplasty. Few weight percentage of nanoLDH was uniformly dispersed in the bone cement matrix to have adequate interaction with matrix polymer. Mechanical strength, stiffness, toughness, and fatigue resistance of the nanocomposites are found to be higher than that of pure bone cement. Nanocomposites are thermally stable as compared to pristine bone cement. Direct mixing of the nanoLDH without any organic solvent makes these nanocomposites biocompatible. Biocompatibility was evaluated and compared with that of commercial bone cement by measuring hydrophilic nature, hemolysis assay, thrombosis assay, and deposition of apatite in simulated body fluid immersion. Finally, the viability of human osteoblast cells on the above developed nanocomposites was testified for actual biocompatibility. The experiment showed better cell growth in nanocomposites as compared to pure bone cement. Thus, these nanocomposites are found to be better grouting material than bone cement. PMID:22733710

  20. Proceedings of the 2015 Santa Fe Bone Symposium: Clinical Applications of Scientific Advances in Osteoporosis and Metabolic Bone Disease.

    PubMed

    Lewiecki, E Michael; Baron, Roland; Bilezikian, John P; Gagel, Robert E; Leonard, Mary B; Leslie, William D; McClung, Michael R; Miller, Paul D

    2016-01-01

    The 2015 Santa Fe Bone Symposium was a venue for healthcare professionals and clinical researchers to present and discuss the clinical relevance of recent advances in the science of skeletal disorders, with a focus on osteoporosis and metabolic bone disease. Symposium topics included new developments in the translation of basic bone science to improved patient care, osteoporosis treatment duration, pediatric bone disease, update of fracture risk assessment, cancer treatment-related bone loss, fracture liaison services, a review of the most significant studies of the past year, and the use of telementoring with Bone Health Extension for Community Healthcare Outcomes, a force multiplier to improve the care of osteoporosis in underserved communities. PMID:26750746

  1. Potential role of proinflammatory cytokines in nerve damage related bone loss.

    PubMed

    Miesse, Andrew M; Willey, Jeffrey S; Bateman, Ted A

    2004-01-01

    An estimated 375,000 people are currently suffering from spinal cord injuries and another 1.5 million are afflicted by peripheral nerve damage in the United States. Wolf's Law states that a bone grows or remodels in response to the stresses that are placed on it. Forces applied to bones that occur due to normal daily activity allow for healthy resorption and formation of bones. Periods of immobilization caused by nerve damage have a profound effect on the integrity of bone, causing an increased risk of bone fracture. The need for investigating ways of combating this secondary effect of nerve damage is imperative to the long-term health of spinal cord injury and peripheral nerve damage patients. Our lab uses two sciatic nerve damage models in mice to mimic the bone loss caused by recoverable, sciatic nerve crush (NC), and non-recoverable, sciatic neurectomy (NX), injuries. We are examining the hypothesis that recoverable damage actually causes an accelerated loss of bone mass compared to the permanently damaged nerve because of the transport of proinflammatory cytokines from the site of the nerve damage to the locally affected bone. This inflammatory response, and the hypothesized differences between the two models, will be examined via ELISA of the quadriceps to investigate the relative degree of proinflammatory cytokines local to the damage site. Understanding the cellular mechanisms that occur at nerve injury sites will allow for improved care and long-term treatment of patients. A preliminary analysis of the bone loss associate with these two nerve injury models indicate approximately a 50% greater decline in femoral mass of the NC femur compared to the NX limb, supporting the proinflammatory hypothesis. PMID:15133969

  2. Potential of Raman spectroscopy for evaluation of bone quality in osteoporosis patients: results of a prospective study

    NASA Astrophysics Data System (ADS)

    Mandair, Gurjit S.; Esmonde-White, Francis W. L.; Akhter, Mohammed P.; Swift, Aaron M.; Kreider, Jaclynn; Goldstein, Steven A.; Recker, Robert R.; Morris, Michael D.

    2010-02-01

    As part of our ongoing assessment of bone tissue composition and structure, we report the first experimental protocols of a prospective study to investigate the potential of using Raman spectroscopy to diagnose and predict skeletal fragility in postmenopausal osteoporosis patients. This multi-center study will assess several potential spectroscopic and X-ray based diagnostic techniques. One hundred and twenty participants will be enrolled in this five year study and the investigators will be blinded to information concerning patient history and status. Iliac crest bone biopsy specimens are provided with no identifying information except a patient study number. Our team will use micro-computed tomography (micro-CT) to identify regions of interest in both cortical and cancellous bone from specimens delivered to us. Raman mapping will be performed using a line-focused 785 nm laser in order to obtain local and averaged values on several spectroscopic metrics of bone quality. These metrics include carbonate/phosphate and phosphate/matrix ratios. Results from an initial set of biopsies will be presented. Protocols for obtaining measurements are discussed, with emphasis on the challenges presented by the use of fixed and polymer embedded specimens. These protocols are illustrated will data from a biopsy specimen.

  3. Regulation of Sclerostin Expression in Multiple Myeloma by Dkk-1: A Potential Therapeutic Strategy for Myeloma Bone Disease.

    PubMed

    Eda, Homare; Santo, Loredana; Wein, Marc N; Hu, Dorothy Z; Cirstea, Diana D; Nemani, Neeharika; Tai, Yu-Tzu; Raines, Sarah E; Kuhstoss, Stuart Allen; Munshi, Nikhil C; Kronenberg, Henry M; Raje, Noopur S

    2016-06-01

    Sclerostin is a potent inhibitor of osteoblastogenesis. Interestingly, newly diagnosed multiple myeloma (MM) patients have high levels of circulating sclerostin that correlate with disease stage and fractures. However, the source and impact of sclerostin in MM remains to be defined. Our goal was to determine the role of sclerostin in the biology of MM and its bone microenvironment as well as investigate the effect of targeting sclerostin with a neutralizing antibody (scl-Ab) in MM bone disease. Here we confirm increased sclerostin levels in MM compared with precursor disease states like monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM. Furthermore, we found that a humanized MM xenograft mouse model bearing human MM cells (NOD-SCID.CB17 male mice injected intravenously with 2.5 million of MM1.S-Luc-GFP cells) demonstrated significantly higher concentrations of mouse-derived sclerostin, suggesting a microenvironmental source of sclerostin. Associated with the increased sclerostin levels, activated β-catenin expression levels were lower than normal in MM mouse bone marrow. Importantly, a high-affinity grade scl-Ab reversed osteolytic bone disease in this animal model. Because scl-Ab did not demonstrate significant in vitro anti-MM activity, we combined it with the proteasome inhibitor carfilzomib. Our data demonstrated that this combination therapy significantly inhibited tumor burden and improved bone disease in our in vivo MM mouse model. In agreement with our in vivo data, sclerostin expression was noted in marrow stromal cells and osteoblasts of MM patient bone marrow samples. Moreover, MM cells stimulated sclerostin expression in immature osteoblasts while inhibiting osteoblast differentiation in vitro. This was in part regulated by Dkk-1 secreted by MM cells and is a potential mechanism contributing to the osteoblast dysfunction noted in MM. Our data confirm the role of sclerostin as a potential therapeutic target in MM bone disease

  4. Biosilica-glass formation using enzymes from sponges [silicatein]: Basic aspects and application in biomedicine [bone reconstitution material and osteoporosis

    NASA Astrophysics Data System (ADS)

    Wang, Shun-Feng; Wang, Xiao-Hong; Gan, Lu; Wiens, Matthias; Schröder, Heinz C.; Müller, Werner E. G.

    2011-09-01

    In the last 15 years biomineralization, in particular biosilicification (i.e., the formation of biogenic silica, SiO2), has become an exciting source of inspiration for the development of novel bionic approaches, following "Nature as model". Among the silica forming organisms there are the sponges that have the unique property to catalyze their silica skeletons by a specific enzyme termed silicatein. In the present review we summarize the present state of knowledge on silicatein-mediated "biosilica" formation in marine sponges, the involvement of further molecules in silica metabolism and their potential application in biomedicine. Recent advancements in the production of bone replacement material and in the potential use as a component in the treatment of osteoporosis are highlighted.

  5. EVOKED POTENTIALS, PHYSIOLOGICAL METHODS WITH HUMAN APPLICATIONS

    EPA Science Inventory

    A number of tests and test batteries have been developed and implemented for detecting potential neurotoxicity in humans. n some cases test results may suggest specific dysfunction. hile tests in laboratory animals are often used to project the potential for adverse health effect...

  6. Natural Products from Chinese Medicines with Potential Benefits to Bone Health.

    PubMed

    Che, Chun-Tao; Wong, Man Sau; Lam, Christopher Wai Kei

    2016-01-01

    Osteoporosis is a progressive, systemic bone disorder characterized by loss of bone mass and microstructure, leading to reduced bone strength and increased risk of fracture. It is often associated with reduced quality of life and other medical complications. The disease is common in the aging population, particularly among postmenopausal women and patients who receive long-term steroidal therapy. Given the rapid growth of the aging population, increasing life expectancy, the prevalence of bone loss, and financial burden to the healthcare system and individuals, demand for new therapeutic agents and nutritional supplements for the management and promotion of bone health is pressing. With the advent of global interest in complementary and alternative medicine and natural products, Chinese medicine serves as a viable source to offer benefits for the improvement and maintenance of bone health. This review summarizes the scientific information obtained from recent literatures on the chemical ingredients of Chinese medicinal plants that have been reported to possess osteoprotective and related properties in cell-based and/or animal models. Some of these natural products (or their derivatives) may become promising leads for development into dietary supplements or therapeutic drugs. PMID:26927052

  7. Bone and skeletal muscle: Key players in mechanotransduction and potential overlapping mechanisms.

    PubMed

    Goodman, Craig A; Hornberger, Troy A; Robling, Alexander G

    2015-11-01

    The development and maintenance of skeletal muscle and bone mass is critical for movement, health and issues associated with the quality of life. Skeletal muscle and bone mass are regulated by a variety of factors that include changes in mechanical loading. Moreover, bone mass is, in large part, regulated by muscle-derived mechanical forces and thus by changes in muscle mass/strength. A thorough understanding of the cellular mechanism(s) responsible for mechanotransduction in bone and skeletal muscle is essential for the development of effective exercise and pharmaceutical strategies aimed at increasing, and/or preventing the loss of, mass in these tissues. Thus, in this review we will attempt to summarize the current evidence for the major molecular mechanisms involved in mechanotransduction in skeletal muscle and bone. By examining the differences and similarities in mechanotransduction between these two tissues, it is hoped that this review will stimulate new insights and ideas for future research and promote collaboration between bone and muscle biologists.(1). PMID:26453495

  8. Gremlin 1 Identifies a Skeletal Stem Cell with Bone, Cartilage, and Reticular Stromal Potential

    PubMed Central

    Worthley, Daniel L.; Churchill, Michael; Compton, Jocelyn T.; Tailor, Yagnesh; Rao, Meenakshi; Si, Yiling; Levin, Daniel; Schwartz, Matthew G.; Uygur, Aysu; Hayakawa, Yoku; Gross, Stefanie; Renz, Bernhard W.; Setlik, Wanda; Martinez, Ashley N.; Chen, Xiaowei; Nizami, Saqib; Lee, Heon Goo; Kang, H. Paco; Caldwell, Jon-Michael; Asfaha, Samuel; Westphalen, C. Benedikt; Graham, Trevor; Jin, Guangchun; Nagar, Karan; Wang, Hongshan; Kheirbek, Mazen A.; Kolhe, Alka; Carpenter, Jared; Glaire, Mark; Nair, Abhinav; Renders, Simon; Manieri, Nicholas; Muthupalani, Sureshkumar; Fox, James G.; Reichert, Maximilian; Giraud, Andrew S.; Schwabe, Robert F.; Pradere, Jean-Phillipe; Walton, Katherine; Prakash, Ajay; Gumucio, Deborah; Rustgi, Anil K.; Stappenbeck, Thaddeus S.; Friedman, Richard A.; Gershon, Michael D.; Sims, Peter; Grikscheit, Tracy; Lee, Francis Y.; Karsenty, Gerard; Mukherjee, Siddhartha; Wang, Timothy C.

    2014-01-01

    The stem cells that maintain and repair the postnatal skeleton remain undefined. One model suggests that perisinusoidal mesenchymal stem cells (MSCs) give rise to osteoblasts, chondrocytes, marrow stromal cells, and adipocytes, although the existence of these cells has not been proven through fate-mapping experiments. We demonstrate here that expression of the bone morphogenetic protein (BMP) antagonist gremlin 1 defines a population of osteochondroreticular (OCR) stem cells in the bone marrow. OCR stem cells self-renew and generate osteoblasts, chondrocytes, and reticular marrow stromal cells, but not adipocytes. OCR stem cells are concentrated within the metaphysis of long bones not in the perisinusoidal space and are needed for bone development, bone remodeling, and fracture repair. Grem1 expression also identifies intestinal reticular stem cells (iRSCs) that are cells of origin for the periepithelial intestinal mesenchymal sheath. Grem1 expression identifies distinct connective tissue stem cells in both the bone (OCR stem cells) and the intestine (iRSCs). PMID:25594183

  9. Histologic Evaluation of Bone Healing Capacity Following Application of Inorganic Bovine Bone and a New Allograft Material in Rabbit Calvaria

    PubMed Central

    Paknejad, Mojgan; Rokn, AmirReza; Rouzmeh, Nina; Heidari, Mohadeseh; Titidej, Azadehzeinab; Kharazifard, Mohammad Javad; Mehrfard, Ali

    2015-01-01

    Objectives: Considering the importance of bone augmentation prior to implant placement in order to obtain adequate bone quality and quantity, many studies have been conducted to evaluate different techniques and materials regarding new bone formation. In this study, we investigated the bone healing capacity of two different materials deproteinized bovine bone mineral (DBBM with the trade name of Bio-Oss) and demineralized freeze-dried bone allograft (DFDBA with the trade name of DynaGraft). Materials and Methods: This randomized blinded prospective study was conducted on twelve New Zealand white rabbits. Three cranial defects with an equal diameter were created on their calvarium. Subsequently, they were distributed into three groups: 1. The control group without any treatment; 2. The Bio-Oss group; 3. The DynaGraft group. After 30 days, the animals were sacrificed for histologic and histomorphometric analysis. Results: Substantial new bone formation was observed in both groups. DynaGraft: 56/1 % ± 15/1 and Bio-Oss: 53/55 % ± 13/5 compared to the control group: 28/6 % ± 11/2. All groups showed slight inflammation and a small amount of residual biomaterial was observed. Conclusion: Considerable new bone formation was demonstrated in both DynaGraft and Bio-Oss groups in comparison with the control group. Both materials are considered biocompatible regarding the negligible foreign body reaction. PMID:26005452

  10. Hydroxyapatite from fish scale for potential use as bone scaffold or regenerative material.

    PubMed

    Pon-On, Weeraphat; Suntornsaratoon, Panan; Charoenphandhu, Narattaphol; Thongbunchoo, Jirawan; Krishnamra, Nateetip; Tang, I Ming

    2016-05-01

    The present paper studies the physico-chemical, bioactivity and biological properties of hydroxyapatite (HA) which is derived from fish scale (FS) (FSHA) and compares them with those of synthesized HA (sHA) obtained by co-precipitation from chemical solution as a standard. The analysis shows that the FSHA is composed of flat-plate nanocrystal with a narrow width size of about 15-20 nm and having a range of 100 nm in length and that the calcium phosphate ratio (Ca/P) is 2.01 (Ca-rich CaP). Whereas, synthesized HA consists of sub-micron HA particle having a Ca/P ratio of 1.65. Bioactivity test shows that the FSHA forms more new apatite than does the sHA after being incubated in simulated body fluid (SBF) for 7 days. Moreover, the biocompatibility study shows a higher osteoblast like cell adhesion on the FSHA surface than on the sHA substrate after 3 days of culturing. Our results also show the shape of the osteoblast cells on the FSHA changes from being a rounded shape to being a flattened shape reflecting its spreading behavior on this surface. MTT assay and ALP analysis show significant increases in the proliferation and activity of osteoblasts over the FSHA scaffold after 5 days of culturing as compared to those covering the sHA substrates. These results confirm that the bio-materials derived from fish scale (FSHA) are biologically better than the chemically synthesized HA and have the potential for use as a bone scaffold or as regenerative materials. PMID:26952413

  11. The application of cone-beam CT in the aging of bone calluses: a new perspective?

    PubMed

    Cappella, A; Amadasi, A; Gaudio, D; Gibelli, D; Borgonovo, S; Di Giancamillo, M; Cattaneo, C

    2013-11-01

    In the forensic and anthropological fields, the assessment of the age of a bone callus can be crucial for a correct analysis of injuries in the skeleton. To our knowledge, the studies which have focused on this topic are mainly clinical and still leave much to be desired for forensic purposes, particularly in looking for better methods for aging calluses in view of criminalistic applications. This study aims at evaluating the aid cone-beam CT can give in the investigation of the inner structure of fractures and calluses, thus acquiring a better knowledge of the process of bone remodeling. A total of 13 fractures (three without callus formation and ten with visible callus) of known age from cadavers were subjected to radiological investigations with digital radiography (DR) (conventional radiography) and cone-beam CT with the major aim of investigating the differences between DR and tomographic images when studying the inner and outer structures of bone healing. Results showed how with cone-beam CT the structure of the callus is clearly visible with higher specificity and definition and much more information on mineralization in different sections and planes. These results could lay the foundation for new perspectives on bone callus evaluation and aging with cone-beam CT, a user-friendly and skillful technique which in some instances can also be used extensively on the living (e.g., in cases of child abuse) with reduced exposition to radiation. PMID:23389391

  12. High frequency bone conduction auditory evoked potentials in the guinea pig: Assessing cochlear injury after ossicular chain manipulation.

    PubMed

    Bergin, M J; Bird, P A; Vlajkovic, S M; Thorne, P R

    2015-12-01

    Permanent high frequency (>4 kHz) sensorineural hearing loss following middle ear surgery occurs in up to 25% of patients. The aetiology of this loss is poorly understood and may involve transmission of supra-physiological forces down the ossicular chain to the cochlea. Investigating the mechanisms of this injury using animal models is challenging, as evaluating cochlear function with evoked potentials is confounded when ossicular manipulation disrupts the normal air conduction (AC) pathway. Bone conduction (BC) using clinical bone vibrators in small animals is limited by poor transducer output at high frequencies sensitive to trauma. The objectives of the present study were firstly to evaluate a novel high frequency bone conduction transducer with evoked auditory potentials in a guinea pig model, and secondly to use this model to investigate the impact of middle ear surgical manipulation on cochlear function. We modified a magnetostrictive device as a high frequency BC transducer and evaluated its performance by comparison with a calibrated AC transducer at frequencies up to 32 kHz using the auditory brainstem response (ABR), compound action potential (CAP) and summating potential (SP). To mimic a middle ear traumatising stimulus, a rotating bur was brought in to contact with the incudomalleal complex and the effect on evoked cochlear potentials was observed. BC-evoked potentials followed the same input-output function pattern as AC potentials for all ABR frequencies. Deterioration in CAP and SP thresholds was observed after ossicular manipulation. It is possible to use high frequency BC to evoke responses from the injury sensitive basal region of the cochlea and so not rely on AC with the potential confounder of conductive hearing loss. Ongoing research explores how these findings evolve over time, and ways in which injury may be reduced and the cochlea protected during middle ear surgery. PMID:26493491

  13. Spaceflight-relevant types of ionizing radiation and cortical bone: Potential LET effect?

    PubMed

    Lloyd, Shane A J; Bandstra, Eric R; Travis, Neil D; Nelson, Gregory A; Bourland, J Daniel; Pecaut, Michael J; Gridley, Daila S; Willey, Jeffrey S; Bateman, Ted A

    2008-01-01

    Extended exposure to microgravity conditions results in significant bone loss. Coupled with radiation exposure, this phenomenon may place astronauts at a greater risk for mission-critical fractures. In a previous study, we identified a profound and prolonged loss of trabecular bone (29-39%) in mice following exposure to an acute, 2 Gy dose of radiation simulating both solar and cosmic sources. However, because skeletal strength depends on trabecular and cortical bone, accurate assessment of strength requires analysis of both bone compartments. The objective of the present study was to examine various properties of cortical bone in mice following exposure to multiple types of spaceflight-relevant radiation. Nine-week old, female C57BL/6 mice were sacrificed 110 days after exposure to a single, whole body, 2 Gy dose of gamma, proton, carbon, or iron radiation. Femora were evaluated with biomechanical testing, microcomputed tomography, quantitative histomorphometry, percent mineral content, and micro-hardness analysis. Compared to non-irradiated controls, there were significant differences compared to carbon or iron radiation for only fracture force, medullary area and mineral content. A greater differential effect based on linear energy transfer (LET) level may be present: high-LET (carbon or iron) particle irradiation was associated with a decline in structural properties (maximum force, fracture force, medullary area, and cortical porosity) and mineral composition compared to low-LET radiation (gamma and proton). Bone loss following irradiation appears to be largely specific to trabecular bone and may indicate unique biological microenvironments and microdosimetry conditions. However, the limited time points examined and non-haversian skeletal structure of the mice employed highlight the need for further investigation. PMID:19122806

  14. Spaceflight-relevant types of ionizing radiation and cortical bone: Potential LET effect?

    PubMed Central

    Lloyd, Shane A.J.; Bandstra, Eric R.; Travis, Neil D.; Nelson, Gregory A.; Bourland, J. Daniel; Pecaut, Michael J.; Gridley, Daila S.; Willey, Jeffrey S.; Bateman, Ted A.

    2008-01-01

    Extended exposure to microgravity conditions results in significant bone loss. Coupled with radiation exposure, this phenomenon may place astronauts at a greater risk for mission-critical fractures. In a previous study, we identified a profound and prolonged loss of trabecular bone (29−39%) in mice following exposure to an acute, 2 Gy dose of radiation simulating both solar and cosmic sources. However, because skeletal strength depends on trabecular and cortical bone, accurate assessment of strength requires analysis of both bone compartments. The objective of the present study was to examine various properties of cortical bone in mice following exposure to multiple types of spaceflight-relevant radiation. Nine-week old, female C57BL/6 mice were sacrificed 110 days after exposure to a single, whole body, 2 Gy dose of gamma, proton, carbon, or iron radiation. Femora were evaluated with biomechanical testing, microcomputed tomography, quantitative histomorphometry, percent mineral content, and micro-hardness analysis. Compared to non-irradiated controls, there were significant differences compared to carbon or iron radiation for only fracture force, medullary area and mineral content. A greater differential effect based on linear energy transfer (LET) level may be present: high-LET (carbon or iron) particle irradiation was associated with a decline in structural properties (maximum force, fracture force, medullary area, and cortical porosity) and mineral composition compared to low-LET radiation (gamma and proton). Bone loss following irradiation appears to be largely specific to trabecular bone and may indicate unique biological microenvironments and microdosimetry conditions. However, the limited time points examined and non-haversian skeletal structure of the mice employed highlight the need for further investigation. PMID:19122806

  15. Spaceflight-relevant types of ionizing radiation and cortical bone: Potential LET effect?

    NASA Astrophysics Data System (ADS)

    Lloyd, Shane A. J.; Bandstra, Eric R.; Travis, Neil D.; Nelson, Gregory A.; Bourland, J. Daniel; Pecaut, Michael J.; Gridley, Daila S.; Willey, Jeffrey S.; Bateman, Ted A.

    2008-12-01

    Extended exposure to microgravity conditions results in significant bone loss. Coupled with radiation exposure, this phenomenon may place astronauts at a greater risk for mission-critical fractures. In a previous study, we identified a profound and prolonged loss of trabecular bone (29-39%) in mice following exposure to an acute, 2 Gy dose of radiation simulating both solar and cosmic sources. However, because skeletal strength depends on trabecular and cortical bone, accurate assessment of strength requires analysis of both bone compartments. The objective of the present study was to examine various properties of cortical bone in mice following exposure to multiple types of spaceflight-relevant radiation. Nine-week old, female C57BL/6 mice were sacrificed 110 days after exposure to a single, whole body, 2 Gy dose of gamma, proton, carbon, or iron radiation. Femora were evaluated with biomechanical testing, microcomputed tomography, quantitative histomorphometry, percent mineral content, and micro-hardness analysis. Compared to non-irradiated controls, there were significant differences compared to carbon or iron radiation for only fracture force, medullary area and mineral content. A greater differential effect based on linear energy transfer (LET) level may be present: high-LET (carbon or iron) particle irradiation was associated with a decline in structural properties (maximum force, fracture force, medullary area, and cortical porosity) and mineral composition compared to low-LET radiation (gamma and proton). Bone loss following irradiation appears to be largely specific to trabecular bone and may indicate unique biological microenvironments and microdosimetry conditions. However, the limited time points examined and non-haversian skeletal structure of the mice employed highlight the need for further investigation.

  16. Chronic foot-shock stress potentiates the influx of bone marrow-derived microglia into hippocampus.

    PubMed

    Brevet, Marie; Kojima, Hideto; Asakawa, Akihiro; Atsuchi, Kaori; Ushikai, Miharu; Ataka, Koji; Inui, Akio; Kimura, Hiroshi; Sevestre, Henri; Fujimiya, Mineko

    2010-07-01

    For several years, a new population of microglia derived from bone marrow has been described in multiple settings such as infection, trauma, and neurodegenerative disease. The aim of this study was to investigate the migration of bone marrow-derived cells to the brain parenchyma after stress exposure. Stress exposure was performed in mice that had received bone marrow transplantation from GFP mice, allowing identification of blood-derived elements within the brain. Electric foot-shock exposure was chosen because of its ability to serve as fundamental and physical stress in mice. Bone marrow-derived GFP(+) cells migrated to the ventral part of the hippocampus and acquired a ramified microglia-like morphology. Microglia marker Iba1 was expressed by 100% of the ramified cells, whereas ramified cells were negative for the astrocyte marker GFAP. Compared with the case in the control group, ramified cells significantly increased after chronic exposure to stress (5 days). One month after 5 days of stress exposure, ramified cells significantly decreased in ventral hippocampus compared with the group examined immediately after the last stress exposure. We report for the first time the migration of bone marrow-derived cells to the ventral hippocampus after stress exposure. These cells have the characteristics of microglia. Mechanisms responsible for this migration and their roles in the brain remain to be determined. PMID:20155811

  17. Novel 3D Tissue Engineered Bone Model, Biomimetic Nanomaterials, and Cold Atmospheric Plasma Technique for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Wang, Mian

    This thesis research is consist of four chapters, including biomimetic three-dimensional tissue engineered nanostructured bone model for breast cancer bone metastasis study (Chapter one), cold atmospheric plasma for selectively ablating metastatic breast cancer (Chapter two), design of biomimetic and bioactive cold plasma modified nanostructured scaffolds for enhanced osteogenic differentiation of bone marrow derived mesenchymal stem cells (Chapter three), and enhanced osteoblast and mesenchymal stem cell functions on titanium with hydrothermally treated nanocrystalline hydroxyapatite/magnetically treated carbon nanotubes for orthopedic applications (Chapter four). All the thesis research is focused on nanomaterials and the use of cold plasma technique for various biomedical applications.

  18. MicroRNAs: Potential Biomarkers and Therapeutic Targets for Alveolar Bone Loss in Periodontal Disease

    PubMed Central

    Kagiya, Tadayoshi

    2016-01-01

    Periodontal disease is an inflammatory disease caused by bacterial infection of tooth-supporting structures, which results in the destruction of alveolar bone. Osteoclasts play a central role in bone destruction. Osteoclasts are tartrate-resistant acid phosphatase (TRAP)-positive multinucleated giant cells derived from hematopoietic stem cells. Recently, we and other researchers revealed that microRNAs are involved in osteoclast differentiation. MicroRNAs are novel, single-stranded, non-coding, small (20–22 nucleotides) RNAs that act in a sequence-specific manner to regulate gene expression at the post-transcriptional level through cleavage or translational repression of their target mRNAs. They regulate various biological activities such as cellular differentiation, apoptosis, cancer development, and inflammatory responses. In this review, the roles of microRNAs in osteoclast differentiation and function during alveolar bone destruction in periodontal disease are described. PMID:27529224

  19. MicroRNAs: Potential Biomarkers and Therapeutic Targets for Alveolar Bone Loss in Periodontal Disease.

    PubMed

    Kagiya, Tadayoshi

    2016-01-01

    Periodontal disease is an inflammatory disease caused by bacterial infection of tooth-supporting structures, which results in the destruction of alveolar bone. Osteoclasts play a central role in bone destruction. Osteoclasts are tartrate-resistant acid phosphatase (TRAP)-positive multinucleated giant cells derived from hematopoietic stem cells. Recently, we and other researchers revealed that microRNAs are involved in osteoclast differentiation. MicroRNAs are novel, single-stranded, non-coding, small (20-22 nucleotides) RNAs that act in a sequence-specific manner to regulate gene expression at the post-transcriptional level through cleavage or translational repression of their target mRNAs. They regulate various biological activities such as cellular differentiation, apoptosis, cancer development, and inflammatory responses. In this review, the roles of microRNAs in osteoclast differentiation and function during alveolar bone destruction in periodontal disease are described. PMID:27529224

  20. Development of an Automated Bone Mineral Density Software Application: Facilitation Radiologic Reporting and Improvement of Accuracy.

    PubMed

    Tsai, I-Ta; Tsai, Meng-Yuan; Wu, Ming-Ting; Chen, Clement Kuen-Huang

    2016-06-01

    The conventional method of bone mineral density (BMD) report production by dictation and transcription is time consuming and prone to error. We developed an automated BMD reporting system based on the raw data from a dual energy X-ray absorptiometry (DXA) scanner for facilitating the report generation. The automated BMD reporting system, a web application, digests the DXA's raw data and automatically generates preliminary reports. In Jan. 2014, 500 examinations were randomized into an automatic group (AG) and a manual group (MG), and the speed of report generation was compared. For evaluation of the accuracy and analysis of errors, 5120 examinations during Jan. 2013 and Dec. 2013 were enrolled retrospectively, and the context of automatically generated reports (AR) was compared with the formal manual reports (MR). The average time spent for report generation in AG and in MG was 264 and 1452 s, respectively (p < 0.001). The accuracy of calculation of T and Z scores in AR is 100 %. The overall accuracy of AR and MR is 98.8 and 93.7 %, respectively (p < 0.001). The mis-categorization rate in AR and MR is 0.039 and 0.273 %, respectively (p = 0.0013). Errors occurred in AR and can be grouped into key-in errors by technicians and need for additional judgements. We constructed an efficient and reliable automated BMD reporting system. It facilitates current clinical service and potentially prevents human errors from technicians, transcriptionists, and radiologists. PMID:26644156

  1. Autologous bone marrow concentrate: review and application of a novel intra-articular orthobiologic for cartilage disease.

    PubMed

    Sampson, Steven; Botto-van Bemden, Angie; Aufiero, Danielle

    2013-09-01

    Younger adults, aged < 65 years, increasingly present to their physicians with advanced cartilage disease or post-traumatic osteoarthritis. A number of treatments exist for lessening patient pain and improving patient function. However, many patients are becoming aware of the potential of regenerative therapies and are now seeking solutions to the impaired biology underlying their conditions rather than addressing only their symptoms. Patients do not want to merely lessen their symptoms temporarily with a surgical procedure that replaces damaged tissue, but instead seek correction and repair of the underlying biology to regenerate damaged tissue and alleviate their symptoms altogether. Current therapies for patients with cartilage disease or osteoarthritis range from non-surgical intra-articular injections with biologics, such as hyaluronic acid (HA), to total joint arthroplasty for advanced stages of disease. Total joint arthroplasty is a successful procedure for patients aged > 65 years; however, the limited long-term durability of implanted prostheses decreases the preference of using such methods in more active patients aged < 65 years. The potential of cell-based orthobiologic injection therapies (pertaining to therapeutic injectables that aim to restore the biologic environment and/or structural components of diseased or damaged musculoskeletal tissue) is of tremendous interest for younger, more active patients, and is even more appealing in that such therapy can be delivered at point-of-care in the clinic during an office visit. Notably, the exponential rate of progress in biotechnology has allowed for immediate application of myriad novel therapies prior to clear evidence of benefit from randomized clinical trials. Orthobiologic intra-articular injection therapies include HA and platelet-rich plasma (PRP). We report on current, available findings for a third-generation intra-articular orthobiologic injectable therapy for cartilage disease, bone marrow

  2. Application of bioabsorbable screw fixation for anterior cervical decompression and bone grafting

    PubMed Central

    Zhao, Bo; Qiu, Xiaowen; Wang, Dong; Li, Haopeng; He, Xijing

    2016-01-01

    OBJECTIVES: To examine the application of bioabsorbable screws for anterior cervical decompression and bone grafting fixation and to study their clinical effects in the treatment of cervical spondylosis. METHODS: From March 2007 to September 2012, 56 patients, 36 males and 20 females (38-79 years old, average 58.3±9.47 years), underwent a novel operation. Grafts were fixed by bioabsorbable screws (PLLA, 2.7 mm in diameter) after anterior decompression. The bioabsorbable screws were inserted from the midline of the graft bone to the bone surface of the upper and lower vertebrae at 45 degree angles. Patients were evaluated post-operatively to observe the improvement of symptoms and evaluate the fusion of the bone. The Japanese Orthopaedic Association (JOA) score was used to evaluate the recovery of neurological functions. RESULTS: All screws were successfully inserted, with no broken screws. The rate of symptom improvement was 87.5%. All of the grafts fused well with no extrusion. The average time for graft fusion was 3.8±0.55 months (range 3-5 months). Three-dimensional reconstruction of CT scans demonstrated that the grafts fused with adjacent vertebrae well and that the screws were absorbed as predicted. The MRI findings showed that the cerebrospinal fluid was unobstructed. No obvious complications appeared in any of the follow-up evaluations. CONCLUSIONS: Cervical spondylosis with one- or two-level involvement can be effectively treated by anterior decompression and bone grafting with bioabsorbable screw fixation. This operative method is safe and can avoid the complications induced by metal implants. PMID:27438565

  3. Strigolactone derivatives for potential crop enhancement applications.

    PubMed

    Screpanti, Claudio; Fonné-Pfister, Raymonde; Lumbroso, Alexandre; Rendine, Stefano; Lachia, Mathilde; De Mesmaeker, Alain

    2016-05-15

    New technologies able to mitigate the main abiotic stresses (i.e., drought, salinity, cold and heat) represent a substantial opportunity to contribute to a sustainable increase of agricultural production. In this context, the recently discovered phytohormone strigolactone is an important area of study which can underpin the quest for new anti-stress technologies. The pleiotropic roles played by strigolactones in plant growth/development and in plant adaptation to environmental changes can pave the way for new innovative crop enhancement applications. Although a significant scientific effort has been dedicated to the strigolactone subject, an updated review with emphasis on the crop protection perspective was missing. This paper aims to analyze the advancement in different areas of the strigolactone domain and the implications for agronomical applications. PMID:27036522

  4. [Potential Applicability of Fecal NIRs: A Review].

    PubMed

    Yan, Xu; Du, Zhou-he; Bai, Shi-qie; Zuo, Yan-chun; Zhou, Xiao-kang; Kou, Jing; Yan, Jia-jun; Zhang, Jian-bo; Li, Ping; You, Ming-hong; Zhang, Yu; Li, Da-xu; Zhang, Chang-bing; Zhang, Jin

    2015-12-01

    Near-infrared reflectance spectroscopy (NIRS) is an inexpensive, rapid, environment-friendly and non-invasive analytical technique that has been extensively applied in the analysis of the dietary attributes and the animal products. Acquisition of dietary attributes is essential for nutritional diagnoses to provide animals with reasonable diet. Traditionally, the calibration equations for the prediction of dietary attributes (e. g. crude protein) are developed from feed NIR spectra and the results of conventional chemical analysis (i. e. reference data). It is difficult to obtain the NIR spectra of forages consumed by grazing animals, so the method of this calibration is inappropriate for free-grazing herbivores. Feces, as the animal's metabolites, contain the information about both the animal's diet and the animal itself. Recently, Fecal-NIRS (F. NIRS) has been directly used to monitor diet information (botanical composition, chemical composition and digestibility), based on correlation between reference data and fecal NIR profile. Subsequently, some additional application (such as sex and species discrimination, reproductive and parasite status) of F. NIRS also is outlined. In the last, application of NIRS in animal manure is summarized. NIRS was shown to be an alternative to conventional wet chemical methods for analyzing some nutrient concentrations in animal manure rapidly. Overall, this paper proves that F. NIRS is a rapid and valid tool for the determination of the dietary attributes and of the physiological status of animal, although more efforts need to be done to improve the accuracy of the F. NIRS technique. Several researchers in English have reviewed the applications of F. NIRS. In China, however, there is a paucity of research and application regarding F. NIRS. We expect that this paper in Chinese will be helpful to the development of F. NIRS in China. At the same time, we propose NIRS as a simple and rapid analytical method for predicting the main

  5. Differentiation potentials of perivascular cells in the bone tissue remodeling zones under microgravity

    NASA Astrophysics Data System (ADS)

    Rodionova, Natalia; Katkova, Olena

    Adaptive remodeling processes in the skeleton bones occur in the close topographical interconnection with blood capillaries followed by perivascular cells. Radioautographic studies with 3Н- thymidine (Kimmel D.B., Fee W.S., 1980; Rodionova N.V., 1989, 2006) has shown that in osteogenesis zones there is sequential differentiation process of the perivascular cells into osteogenic ones. Using electron microscopy and cytochemistry we studied perivsacular cells in metaphysis of the rats femoral bones under conditions of modeling microgravity (28 days duration) and in femoral bonеs metaphyses of rats flown on board of the space laboratory (Spacelab - 2) It was revealed that population of the perivascular cells is not homogeneous in adaptive zones of the remodeling in both control and test groups (lowering support loading). This population comprises adjacent to endothelium little differentiated forms and isolated cells with differentiation features (specific volume of rough endoplasmic reticulum in cytoplasm is increased). Majority of the perivascular cells in the control group reveals reaction to alkaline phosphatase (marker of the osteogenic differentiation). In little differentiated cells this reaction is registered in nucleolus, nucleous and cytoplasm. In differentiating cells activity of the alkaline phosphatase is also detected on the outer surface of the cellular membrane. Unlike the control group in the bones of animals under microgravitaty reaction to the alkaline phosphatase is registered not for all cells of perivascular population. Part of the differentiating perivascular cells does not contain a product of the reaction. There is also visible trend of individual alkaline phosphatase containing perivascular cells amounts decrease (i.e. osteogenic cells-precursors). Under microgravity some little differentiated perivascular cells reveal destruction signs. Found decrease trend of the alkaline phosphatase containing cells (i.e. osteogenic cells) number in

  6. In vitro models for the evaluation of angiogenic potential in bone engineering

    PubMed Central

    Cenni, Elisabetta; Perut, Francesca; Baldini, Nicola

    2011-01-01

    Blood vessels have a fundamental role both in skeletal homeostasis and in bone repair. Angiogenesis is also important for a successful bone engineering. Therefore, scaffolds should be tested for their ability to favour endothelial cell adhesion, proliferation and functions. The type of endothelial cell to use for in vitro assays should be carefully considered, because the properties of these cells may depend on their source. Morphological and functional relationships between endothelial cells and osteoblasts are evaluated with co-cultures, but this model should still be standardized, particularly for distinguishing the two cell types. Platelet-rich plasma and recombinant growth factors may be useful for stimulating angiogenesis. PMID:21042285

  7. [The application progress of human urine derived stem cells in bone tissue engineering].

    PubMed

    Gao, Peng; Jiang, Dapeng; Li, Zhaozhu

    2016-04-01

    The research of bone tissue engineering bases on three basic directions of seed cells, scaffold materials and growth information. Stem cells have been widely studied as seed cells. Human urine-derived stem cell (hUSC) is extracted from urine and described to be adhesion growth, cloning, expression of the majority of mesenchymal stem cell markers and peripheral cell markers, multi-potential and no tumor but stable karyotype with passaging many times. Some researches proposed that hUSC might be a new source of seed cells in tissue engineering because of their invasive and convenient obtention, stable culture and multiple differentiation potential. PMID:27029208

  8. A synthetic compound that potentiates bone morphogenetic protein-2-induced transdifferentiation of myoblasts into the osteoblastic phenotype.

    PubMed

    Kato, Satoshi; Sangadala, Sreedhara; Tomita, Katsuro; Titus, Louisa; Boden, Scott D

    2011-03-01

    There is an urgent need to develop methods that lower costs of using recombinant human bone morphogenetic proteins (BMPs) to promote bone induction. In this study, we demonstrate the osteogenic effect of a low-molecular weight compound, SVAK-12, that potentiated the effects of BMP-2 in inducing transdifferentiation of C2C12 myoblasts into the osteoblastic phenotype. Here, we report a specific compound, SVAK-12, which was selected based on in silico screenings of small-molecule databases using the homology modeled interaction motif of Smurf1-WW2 domain. The enhancement of BMP-2 activity by SVAK-12 was characterized by evaluating a BMP-specific reporter activity and by monitoring the BMP-2-induced expression of mRNA for osteocalcin and alkaline phosphatase (ALP), which are widely accepted marker genes of osteoblast differentiation. Finally, we confirmed these results by also measuring the enhancement of BMP-2-induced activity of ALP. Smurf1 is an E3 ligase that targets osteogenic Smads for ubiquitin-mediated proteasomal degradation. Smurf1 is an interesting potential target to enhance bone formation based on the positive effects on bone of proteins that block Smurf1-binding to Smad targets or in Smurf1-/- knockout mice. Since Smads bind Smurf1 via its WW2 domain, we performed in silico screening to identify compounds that might interact with the Smurf1-WW2 domain. We recently reported the activity of a compound, SVAK-3. However, SVAK-3, while exhibiting BMP-potentiating activity, was not stable and thus warranted a new search for a more stable and efficacious compound among a selected group of candidates. In addition to being more stable, SVAK-12 exhibited a dose-dependent activity in inducing osteoblastic differentiation of myoblastic C2C12 cells even when multiple markers of the osteoblastic phenotype were parallelly monitored. PMID:21110071

  9. Gamma irradiation preserves immunosuppressive potential and inhibits clonogenic capacity of human bone marrow-derived mesenchymal stromal cells

    PubMed Central

    de Andrade, Ana Valéria Gouveia; Riewaldt, Julia; Wehner, Rebekka; Schmitz, Marc; Odendahl, Marcus; Bornhäuser, Martin; Tonn, Torsten

    2014-01-01

    Mesenchymal stromal cells (MSCs) are promising candidates for the treatment of graft-versus-host and autoimmune diseases. Here, by virtue of their immunosuppressive effects, they are discussed to exhibit inhibitory actions on various immune effector cells, including T lymphocytes that promote the underlying pathology. While it becomes apparent that MSCs exhibit their therapeutic effect in a transient manner, they are usually transplanted from third party donors into heavily immunocompromised patients. However, little is known about potential late complications of persisting third party MSCs in these patients. We therefore analysed the effect of gamma irradiation on the potency and proliferation of MSCs to elucidate an irradiation dose, which would allow inhibition of MSC proliferation while at the same time preserving their immunosuppressive function. Bone marrow-derived MSCs (BM-MSCs) were gamma-irradiated at increasing doses of 5, 10 and 30 Gy and subsequently assessed by colony formation unit (CFU)-assay, Annexin V-staining and in a mixed lymphocyte reaction, to assess colony growth, apoptosis and the immunosuppressive capacity, respectively. Complete loss of proliferative capacity measured by colony formation was observed after irradiation with a dose equal to or greater than 10 Gy. No significant decrease of viable cells was detected, as compared to non-irradiated BM-MSCs. Notably, irradiated BM-MSCs remained highly immunosuppressive in vitro for at least 5 days after irradiation. Gamma irradiation does not impair the immunosuppressive capacity of BM-MSCs in vitro and thus might increase the safety of MSC-based cell products in clinical applications. PMID:24655362

  10. Physicochemical Properties and Applications of Poly(lactic-co-glycolic acid) for Use in Bone Regeneration

    PubMed Central

    Félix Lanao, Rosa P.; Jonker, Anika M.; Wolke, Joop G.C.; Jansen, John A.; van Hest, Jan C.M.

    2013-01-01

    Poly(lactic-co-glycolic acid) (PLGA) is the most often used synthetic polymer within the field of bone regeneration owing to its biocompatibility and biodegradability. As a consequence, a large number of medical devices comprising PLGA have been approved for clinical use in humans by the American Food and Drug Administration. As compared with the homopolymers of lactic acid poly(lactic acid) and poly(glycolic acid), the co-polymer PLGA is much more versatile with regard to the control over degradation rate. As a material for bone regeneration, the use of PLGA has been extensively studied for application and is included as either scaffolds, coatings, fibers, or micro- and nanospheres to meet various clinical requirements. PMID:23350707

  11. Thermoluminescence: Potential Applications in Forensic Science

    NASA Technical Reports Server (NTRS)

    Ingham, J. D.; Lawson, D. D.

    1973-01-01

    In crime laboratories one of the most difficult operations is to determine unequivocally whether or not two samples of evidence of the same type were originally part of the same thing or were from the same source. It has been found that high temperature thermoluminescence (room temperature to 723 K) can be used for comparisons of this type, although work to date indicates that there is generally a finite probability for coincidental matching of glass or soil samples. Further work is required to determine and attempt to minimize these probabilities for different types of materials, and to define more clearly the scope of applicability of thermoluminescence to actual forensic situations.

  12. Bone formation of human mesenchymal stem cells harvested from reaming debris is stimulated by low-dose bone morphogenetic protein-7 application in vivo.

    PubMed

    Westhauser, Fabian; Höllig, Melanie; Reible, Bruno; Xiao, Kai; Schmidmaier, Gerhard; Moghaddam, Arash

    2016-12-01

    Stimulation of mesenchymal stem cells (MSC) by bone morphogenetic protein-7 (BMP-7) leads to superior bone formation in vitro. In this in vivo-study we evaluated the use of BMP-7 in combination with MSC isolated from reaming debris (RIA-MSC) and iliac crest bone marrow (BMSC) with micro-computed tomography (mCT)-analysis. β-Tricalciumphosphate scaffolds coated with BMSC and RIA-MSC were stimulated with three different BMP-7-concentrations and implanted ectopically in severe combined immunodeficiency (SCID) mice. Our results demonstrate that RIA-MSC show a higher osteogenic potential in vivo compared to BMSC. Ossification increased in direct correlation with the BMP-7-dose applied, however low-dose-stimulation by BMP-7 was more effective for RIA-MSC. PMID:27621556

  13. Potential effect of angiotensin II receptor blockade in adipose tissue and bone.

    PubMed

    Nakagami, Hironori; Osako, Mariana Kiomy; Morishita, Ryuichi

    2013-01-01

    Recent evidence demonstrated that dysregulation of adipocytokine functions seen in abdominal obesity may be involved in the pathogenesis of the metabolic syndrome. Angiotensinogen, the precursor of angiotensin (Ang) II, is produced primarily in the liver, and also in adipose tissue, where it is up-regulated during the development of obesity and involved in blood pressure regulation and adipose tissue growth. Blockade of renin-angiotensin system (RAS) attenuates weight gain and adiposity by enhanced energy expenditure, and the favorable metabolic effects of telmisartan have been related to its Ang II receptor blockade and action as a partial agonist of peroxisome proliferators activated receptor (PPAR)-γ. PPARγ plays an important role in regulating carbohydrate and lipid metabolism, and ligands for PPARγ can improve insulin sensitivity and reduce triglyceride levels. Similarly, bone metabolism is closely regulated by hormones and cytokines, which have effects on both bone resorption and deposition. It is known that the receptors of Ang II are expressed in culture osteoclasts and osteoblasts, and Ang II is postulated to be able to act upon the cells involved in bone metabolism. In in vitro system, Ang II induced the differentiation and activation of osteoclasts responsible for bone resorption. Importantly, it was demonstrated by the sub-analysis of a recent clinical study that the fracture risk was significantly reduced by the usage of angiotensin-converting enzyme inhibitors. To treat the subgroups of hypertensive patients with osteoporosis RAS can be considered a novel target. PMID:23176218

  14. Revisiting bone targeting potential of novel hydroxyapatite based surface modified PLGA nanoparticles of risedronate: Pharmacokinetic and biochemical assessment.

    PubMed

    Rawat, Purnima; Ahmad, Iqbal; Thomas, Shindu C; Pandey, Shweta; Vohora, Divya; Gupta, Sarika; Ahmad, Farhan Jalees; Talegaonkar, Sushama

    2016-06-15

    Hydroxyapatite based biodegradable mPEG-PLGA nanoparticles of risedronate (mPEG-PLGA-RIS-HA) were prepared by water miscible dialysis method for synergistic treatment of osteoporosis. The bone targeting potential of prepared nanoparticles was evaluated by performing the cell viability study and protein estimation in pre-osteoblast cell line (MC3T3E1). Biochemical and in-vivo pharmacokinetic studies on osteoporotic rat model treated with different formulations were performed. Under the biochemical study ALP, TRAP, HxP and Calcium levels were determined. Osteoporotic model treated with prepared nanoparticles indicated significant effect on bone. Pharmacokinetic studies revealed 6-fold and 4-fold increase in the relative bioavailability after intravenous and oral administration of nanoparticles respectively as compared to marketed formulation confirming better effective drug transport. Biochemical investigations also showed a significant change in biomarker level which ultimately lead to bone formation/resorption. A stability analysis has also been carried out according to ICH guidelines (Q1AR2) and shelf life was found to be 1year and 4 months for the prepared formulation. Thus the results of present studies indicated that mPEG-PLGA-RIS-HA NPs has a great potential for sustained delivery of RIS for the treatment and prevention of osteoporosis and to minimize the adverse effects of RIS typically induced by its oral administration. PMID:27113864

  15. Microbial ribonucleases (RNases): production and application potential.

    PubMed

    Hameş, E Esin; Demir, Tuğçe

    2015-12-01

    Ribonuclease (RNase) is hydrolytic enzyme that catalyzes the cleavage of phosphodiester bonds in RNA. RNases play an important role in the metabolism of cellular RNAs, such as mRNA and rRNA or tRNA maturation. Besides their cellular roles, RNases possess biological activity, cell stimulating properties, cytotoxicity and genotoxicity. Cytotoxic effect of particular microbial RNases was comparable to that of animal derived counterparts. In this respect, microbial RNases have a therapeutic potential as anti-tumor drugs. The significant development of DNA vaccines and the progress of gene therapy trials increased the need for RNases in downstream processes. In addition, RNases are used in different fields, such as food industry for single cell protein preparations, and in some molecular biological studies for the synthesis of specific nucleotides, identifying RNA metabolism and the relationship between protein structure and function. In some cases, the use of bovine or other animal-derived RNases have increased the difficulties due to the safety and regulatory issues. Microbial RNases have promising potential mainly for pharmaceutical purposes as well as downstream processing. Therefore, an effort has been given to determination of optimum fermentation conditions to maximize RNase production from different bacterial and fungal producers. Also immobilization or strain development experiments have been carried out. PMID:26433394

  16. Antarctic Yeasts: Biodiversity and Potential Applications

    NASA Astrophysics Data System (ADS)

    Shivaji, S.; Prasad, G. S.

    This review is an attempt in cataloguing the diversity of yeasts in Antarctica, highlight their biotechnological potential and understand the basis of adaptation to low temperature. As of now several psychrophilic and psychrotolerant yeasts from Antarctic soils and marine waters have been characterized with respect to their growth characteristics, ecological distribution and taxonomic significance. Interestingly most of these species belonged to basidiomycetous yeasts which as a group are known for their ability to circumvent and survive under stress conditions. Simultaneously their possible role as work horses in the biotechnological industry was recognized due to their ability to produce novel enzymes and biomolecules such as agents for the breakdown of xenobiotics, and novel pharmaceutical chemi cals. The high activity of psychrophilic enzymes at low and moderate temperatures offers potential economic benefits. As of now lipases from Pseudozyma antarctica have been extensively studied to understand their unique thermal stability at 90°C and also because of its use in the pharmaceutical, agriculture, food, cosmetics and chemical industry. A few of the other enzymes which have been studied include extracellular alpha-amylase and glucoamylase from the yeast Pseudozyma antarctica (Candida antarctica), an extra-cellular protease from Cryptococcus humicola, an aspartyl proteinase from Cryptococcus humicola, a novel extracellular subtilase from Leucosporidium antarcticum, and a xylanase from Cryptococcus adeliensis

  17. Microwave processing of lunar materials: potential applications

    SciTech Connect

    Meek, T.T.; Cocks, F.H.; Vaniman, D.T.; Wright, R.A.

    1984-01-01

    The microwave processing of lunar materials holds promise for the production of either water, oxygen, primary metals, or ceramic materials. Extra high frequency microwave (EHF) at between 100 and 500 gigahertz have the potential for selective coupling to specific atomic species and a concomitant low energy requirement for the extraction of specific materials, such as oxygen, from lunar ores. The coupling of ultra high frequency (UHF) (e.g., 2.45 gigahertz) microwave frequencies to hydrogen-oxygen bonds might enable the preferential and low energy cost removal (as H/sub 2/O) of implanted protons from the sun or of adosrbed water which might be found in lunar dust in permanently shadowed polar areas. Microwave melting and selective phase melting of lunar materials could also be used either in the preparation of simplified ceramic geometries (e.g., bricks) with custom-tailored microstructures, or for the direct preparation of hermetic walls in underground structures. Speculatively, the preparation of photovoltaic devices based on lunar materials, especially ilmenite, may be a potential use of microwave processing on the moon. Preliminary experiments on UHF melting of terrestrial basalt, basalt/ilmenite and mixtures show that microwave processing is feasible.

  18. Polymer recycling: potential application of radiation technology

    NASA Astrophysics Data System (ADS)

    Burillo, Guillermina; Clough, Roger L.; Czvikovszky, Tibor; Guven, Olgun; Le Moel, Alain; Liu, Weiwei; Singh, Ajit; Yang, Jingtian; Zaharescu, Traian

    2002-04-01

    Management of solid waste is an important problem, which is becoming progressively worse as a byproduct of continuing economic growth and development. Polymeric materials (plastics and rubbers) comprise a steadily increasing proportion of the municipal and industrial waste going into landfill. Development of technologies for reducing polymeric waste, which are acceptable from the environmental standpoint, and which are cost-effective, has proven to be a difficult challenge due to complexities inherent in the reuse of polymers. Establishing optimal processes for the reuse/recycling of polymeric materials thus remains a worldwide challenge as we enter the new century. Due to the ability of ionizing radiation to alter the structure and properties of bulk polymeric materials, and the fact that it is applicable to essentially all polymer types, irradiation holds promise for impacting the polymer waste problem. The three main possibilities for use of radiation in this application are: (1) enhancing the mechanical properties and performance of recovered materials or material blends, principally through crosslinking, or through surface modification of different phases being combined; (2) treatment causing or enhancing the decomposition of polymers, particularly through chain scission, leading to recovery of either low molecular weight mixtures, or powders, for use as chemical feedstocks or additives; (3) production of advanced polymeric materials designed for environmental compatibility. This paper provides an overview of the polymer recycling problem, describes the major technological obstacles to the implementation of recycling technologies, and outlines some of the approaches being taken. A review of radiation-based recycling research is then provided, followed by a discussion of future directions where irradiation may be relevant to the problems currently inhibiting the widespread recycling of polymeric materials.

  19. [Auditory evoked potentials: basics and clinical applications].

    PubMed

    Radeloff, A; Cebulla, M; Shehata-Dieler, W

    2014-09-01

    Auditory evoked potentials (AEPs) are elicited at various levels of the auditory system following acoustic stimulation. Electrocochleography is a technique for recording AEPs of the inner ear. The recording is performed by means of a needle electrode placed on the promontory or non-invasive with tympanic membrane or ear canal electrodes. Clinically, electrocochleography is used for the diagnosis of auditory neuropathy spectrum disorder (ANSD) and endolymphatic hydrops. According to their latencies, AEPs of the central auditory pathway are subdivided into early, middle and late (cortical) AEPs. These AEPs are recorded via surface scalp electrodes. Normally, the larger EEG masks AEPs. For unmasking the AEP, several techniques are applied. Early AEPs or auditory brainstem responses (ABR) are the most widely used AEPs for functional evaluation of the auditory pathway. In contrast to otoacoustic emissions, early AEPs can detect ANSD. Thus, they are more suitable for hearing screening in newborns. For this purpose automated procedures are implemented. PMID:25152975

  20. Potential flow applications to complex configurations

    NASA Technical Reports Server (NTRS)

    Cenko, A.; Tseng, W.; Madson, M.

    1991-01-01

    Recent advances in CFD methods have enabled the analytic calculation of the carriage loads for stores mounted on complex aircraft. The latest results have demonstrated excellent agreement with test data for the F-15 at M = 0.98. However, in a preliminary design environment, the necessity of generating and validating a Euler grid to fit the aircraft and store arrangement may not be feasible, particularly when effects of configuration changes are considered. For that reason alternative approaches which require less time to arrive at an answer deserve consideration. The paper presents the results of a study to determine if potential flow solutions can give acceptable estimates of store carriage loads at transonic speeds in a timely manner.

  1. Theory of the induction of bone sarcoma by bone-seeking alpha emitters and its application to risk assessment

    SciTech Connect

    Petojan, I.M.

    1992-06-01

    This work discusses the theory of bone sarcoma induction by bone seeking alpha emitters, which is based strictly on biological considerations relative to the mechanism of radiation-induced carcinogenesis, identification of cells at risk and their location in bone, bone tissue renewal processes and bone cell kinetics with or without radiation exposure. The model is consistent with the data on bone sarcoma incidence human with incorporated long-lived isotopes Ra-226 + Ra-228. Extrapolation of these data to a low intake region of the basis of the developed theoretical approach suggests that the linear ICRP-UNSCEAR model overestimates carciogenic risk at low doses, possibly by a factor of 2-4. The model suggests a linear response of target cells to the initiation effects of alpha irradiation. The non-linear (linear-quadratic) initial part of dose-response curve for osteosarcoma induction is explained quantitatively by a model based on a promoter effect of regenerative hyperplasia resulting from invitation effects of alpha radiation. The maximum overestimation inherent to the model of the low-level risk due to the the dose-dependent promotion factor is estimated using bo{sup +1}/bo, where bo is a model parameter which is proportional to the normal division rate of osteogenic cells in vivo and which can be estimated within the framework of the model. The model provides confirming evidence that, for radiation protection purposes, endosteal cells may be considered the only group of cells at risk of sarcoma induction by low doses of bone-seeking alpha emitters, whereas the role of marrow stromal (osteogenic) cells as target cells is much more significant with increasing intakes, and can become dominating if intake is high enough.

  2. Marine Origin Collagens and Its Potential Applications

    PubMed Central

    Silva, Tiago H.; Moreira-Silva, Joana; Marques, Ana L. P.; Domingues, Alberta; Bayon, Yves; Reis, Rui L.

    2014-01-01

    Collagens are the most abundant high molecular weight proteins in both invertebrate and vertebrate organisms, including mammals, and possess mainly a structural role, existing different types according with their specific organization in distinct tissues. From this, they have been elected as one of the key biological materials in tissue regeneration approaches. Also, industry is constantly searching for new natural sources of collagen and upgraded methodologies for their production. The most common sources are from bovine and porcine origin, but other ways are making their route, such as recombinant production, but also extraction from marine organisms like fish. Different organisms have been proposed and explored for collagen extraction, allowing the sustainable production of different types of collagens, with properties depending on the kind of organism (and their natural environment) and extraction methodology. Such variety of collagen properties has been further investigated in different ways to render a wide range of applications. The present review aims to shed some light on the contribution of marine collagens for the scientific and technological development of this sector, stressing the opportunities and challenges that they are and most probably will be facing to assume a role as an alternative source for industrial exploitation. PMID:25490254

  3. Development of Thermosensitive Hydrogels of Chitosan, Sodium and Magnesium Glycerophosphate for Bone Regeneration Applications

    PubMed Central

    Lisková, Jana; Bačaková, Lucie; Skwarczyńska, Agata L.; Musial, Olga; Bliznuk, Vitaliy; De Schamphelaere, Karel; Modrzejewska, Zofia; Douglas, Timothy E.L.

    2015-01-01

    Thermosensitive injectable hydrogels based on chitosan neutralized with sodium beta-glycerophosphate (Na-β-GP) have been studied as biomaterials for drug delivery and tissue regeneration. Magnesium (Mg) has been reported to stimulate adhesion and proliferation of bone forming cells. With the aim of improving the suitability of the aforementioned chitosan hydrogels as materials for bone regeneration, Mg was incorporated by partial substitution of Na-β-GP with magnesium glycerophosphate (Mg-GP). Chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were also loaded with the enzyme alkaline phosphatase (ALP) which induces hydrogel mineralization. Hydrogels were characterized physicochemically with respect to mineralizability and gelation kinetics, and biologically with respect to cytocompatibility and cell adhesion. Substitution of Na-β-GP with Mg-GP did not negatively influence mineralizability. Cell biological testing showed that both chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were cytocompatible towards MG63 osteoblast-like cells. Hence, chitosan/Na-β-GP/Mg-GP hydrogels can be used as an alternative to chitosan/Na-β-GP hydrogels for bone regeneration applications. However the incorporation of Mg in the hydrogels during hydrogel formation did not bring any appreciable physicochemical or biological benefit. PMID:25859630

  4. Enrichment of thermosensitive chitosan hydrogels with glycerol and alkaline phosphatase for bone tissue engineering applications.

    PubMed

    Douglas, Timothy E L; Krok-Borkowicz, Małgorzata; Macuda, Aleksandra; Pietryga, Krzysztof; Pamuła, Elżbieta

    2016-01-01

    Thermosensitive injectable chitosan hydrogels can be formed by neutralization of acidic chitosan solutions with sodium betaglycerophosphate (Na-β-GP) coupled with increasing temperature to body temperature. Such hydrogels have been considered for applications in bone regeneration. In this study, chitosan hydrogels were enriched with glycerol and the enzyme alkaline phosphatase (ALP) with a view to improving their suitability as materials for bone tissue engineering. Mineral formation was confirmed by infrared spectroscopy (FTIR) and increases in the mass fraction of the hydrogel not consisting of water. Incorporation of ALP in hydrogels followed by incubation in a solution containing calcium ions and glycerophosphate, a substrate for ALP, led to formation of calcium phosphate within the hydrogel. MG-63 osteoblast-like cells were cultivated in eluates from hydrogels containing ALP and without ALP at different dilutions and directly on the hydrogel samples. Hydrogels containing ALP exhibited superior cytocompatibility to ALP-free hydrogels. These results pave the way for the use of glycerol- and ALP-enriched hydrogels in bone regeneration. PMID:27405261

  5. Development of thermosensitive hydrogels of chitosan, sodium and magnesium glycerophosphate for bone regeneration applications.

    PubMed

    Lisková, Jana; Bačaková, Lucie; Skwarczyńska, Agata L; Musial, Olga; Bliznuk, Vitaliy; De Schamphelaere, Karel; Modrzejewska, Zofia; Douglas, Timothy E L

    2015-01-01

    Thermosensitive injectable hydrogels based on chitosan neutralized with sodium beta-glycerophosphate (Na-β-GP) have been studied as biomaterials for drug delivery and tissue regeneration. Magnesium (Mg) has been reported to stimulate adhesion and proliferation of bone forming cells. With the aim of improving the suitability of the aforementioned chitosan hydrogels as materials for bone regeneration, Mg was incorporated by partial substitution of Na-β-GP with magnesium glycerophosphate (Mg-GP). Chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were also loaded with the enzyme alkaline phosphatase (ALP) which induces hydrogel mineralization. Hydrogels were characterized physicochemically with respect to mineralizability and gelation kinetics, and biologically with respect to cytocompatibility and cell adhesion. Substitution of Na-β-GP with Mg-GP did not negatively influence mineralizability. Cell biological testing showed that both chitosan/Na-β-GP and chitosan/Na-β-GP/Mg-GP hydrogels were cytocompatible towards MG63 osteoblast-like cells. Hence, chitosan/Na-β-GP/Mg-GP hydrogels can be used as an alternative to chitosan/Na-β-GP hydrogels for bone regeneration applications. However the incorporation of Mg in the hydrogels during hydrogel formation did not bring any appreciable physicochemical or biological benefit. PMID:25859630

  6. Applications of the direct photon absorption technique for measuring bone mineral content in vivo. Determination of body composition in vivo

    NASA Technical Reports Server (NTRS)

    Cameron, J. R.

    1972-01-01

    The bone mineral content, BMC, determined by monoenergetic photon absorption technique, of 29 different locations on the long bones and vertebral columns of 24 skeletons was measured. Compressive tests were made on bone from these locations in which the maximum load and maximum stress were measured. Also the ultimate strain, modulus of elasticity and energy absorbed to failure were determined for compact bone from the femoral diaphysis and cancellous bone from the eighth through eleventh thoracic vertebrae. Correlations and predictive relationships between these parameters were examined to investigate the applicability of using the BMC at sites normally measured in vivo, i.e. radius and ulna in estimating the BMC and/or strength of the spine or femoral neck. It was found that the BMC at sites on the same bone were highly correlated r = 0.95 or better; the BMC at sites on different bones were also highly interrelated, r = 0.85. The BMC at various sites on the long bones could be estimated to between 10 and 15 per cent from the BMC of sites on the radius or ulna.

  7. Preparation and biocompatibility evaluation of bioactive glass-forsterite nanocomposite powder for oral bone defects treatment applications.

    PubMed

    Saqaei, Mahboobe; Fathi, Mohammadhossein; Edris, Hossein; Mortazavi, Vajihesadat

    2015-11-01

    Bone defects which emerge around dental implants are often seen when implants are placed in areas with insufficient alveolar bone, in extraction sockets, or around failing implants. Bone regeneration in above-mentioned defects using of bone grafts or bone substitutes may cure the long-term prognoses of dental implants. Biocompatibility, bioactivity and osteogenic properties are key factors affecting the applications of a bone substitute. This study was aimed at preparation, characterization, biocompatibility and bioactivity evaluation of the bioactive glass-forsterite nanocomposite powder as a desired candidate for oral bone defect treatments. Nanocomposite powders containing 58S bioactive glass and different amounts of forsterite nanopowder were synthesized in situ by sol-gel technique. Characterization of the prepared nanocomposite powders and their cytotoxicity assessment was performed via MTT test. Bioactivity assessment was done by immersing the prepared powder in the simulated body fluid (SBF). Results showed that nanocomposite powders containing forsterite with crystallite size of 20-50nm were successfully fabricated by calcination at 600°C. The prepared bioactive glass-forsterite nanocomposite powders revealed high in vitro biocompatibility; besides, the nanocomposite containing 20wt.% forsterite showed a substantial increase in the cell viability compared with control groups. During immersion in SBF, the formation of apatite layer confirmed the bioactivity of bioactive glass-forsterite nanocomposite powders. According to the results, the fabricated nanocomposite powders can be introduced as a promising candidate for oral bone imperfection treatments and hard tissue mend. PMID:26249608

  8. Potential mechanisms underlying the Runx2 induced osteogenesis of bone marrow mesenchymal stem cells

    PubMed Central

    Xu, Jiahai; Li, Zhanghua; Hou, Yudong; Fang, Weijun

    2015-01-01

    Bone marrow derived mesenchymal stem cells (BM-MSCs) belong a type of pluripotent stem cells and can be induced to differentiate into osteoblasts (OB). Runt-related transcription factor 2 (Runx2) is an osteogenesis specific transcription factor and plays an important role in osteogenesis of BM-MSCs. It can promote the expression of osteogenesis related genes, regulate cell cycle progression, improve bone microenvironment and affect functions of chondrocytes and osteoclasts, which have involvement of a large amount of signal molecules including TGF-β, BMP, Notch, Wnt, Hedgehog, FGF and microRNA. In this paper, we summarize the mechanisms underlying the Runx2 induced osteogenesis of BM-MSCs. PMID:26885254

  9. Clinical application of intrauterine bone marrow transplantation for treatment of genetic diseases--feasibility studies.

    PubMed

    Slavin, S; Naparstek, E; Ziegler, M; Lewin, A

    1992-01-01

    Intrauterine bone marrow transplantation (BMT) may represent a new approach for correction of a large variety of genetic disorders in utero. The procedure may become feasible for more genetic disorders in the future, since a large majority of potentially correctible diseases can be diagnosed at an early stage of gestation in utero using molecular probes that permit analysis of small biologic samples and even few cells that may be obtained by chorionic villi biopsy and/or amniocentesis. Haploidentical paternal marrow (2 cases) and sibling bone marrow cells from a disease-free family members, were infused into the fetus. GVHD was avoided following in vitro T-lymphocyte depletion using monoclonal antilymphocyte (CDW52) antibodies (Campath-1) without affecting stem cell viability, similarly to the procedures in routine use in clinical BMT programs in man. Three women underwent intrauterine BMT at 34, 23 and 25 weeks of gestation for metachromatic leucodystrophy (Arylsulfatase A deficiency, 2 cases) and beta thalassemia major (1 case), respectively. A total of 33 x 10(8), 30 x 10(8) and 30 x 10(8) bone marrow cells were infused intraperitoneally (1 case), intraportally plus intraperitoneally (2 cases) with no fetal distress. Although the procedure was uneventful and no clinical evidence of GVHD was observed following delivery, correction of the basic disorders was not accomplished because of anticipated rejection of marrow allografts.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1504665

  10. Generation of an Atlas of the Proximal Femur and Its Application to Trabecular Bone Analysis

    PubMed Central

    Carballido-Gamio, Julio; Folkesson, Jenny; Karampinos, Dimitrios C.; Baum, Thomas; Link, Thomas M.; Majumdar, Sharmila; Krug, Roland

    2013-01-01

    Automatic placement of anatomically corresponding volumes of interest and comparison of parameters against a standard of reference are essential components in studies of trabecular bone. Only recently, in vivo MR images of the proximal femur, an important fracture site, could be acquired with high-spatial resolution. The purpose of this MRI trabecular bone study was two-fold: (1) to generate an atlas of the proximal femur to automatically place anatomically corresponding volumes of interest in a population study and (2) to demonstrate how mean models of geodesic topological analysis parameters can be generated to be used as potential standard of reference. Ten females were used to generate the atlas and geodesic topological analysis models, and 10 females were used to demonstrate the atlas-based trabecular bone analysis. All alignments were based on three-dimensional (3D) multiresolution affine transformations followed by 3D multiresolution free-form deformations. Mean distances less than 1 mm between aligned femora, and sharp edges in the atlas and in fused gray-level images of registered femora indicated that the anatomical variability was well accommodated and explained by the free-form deformations. PMID:21432904

  11. Multiwall carbon nanotubes/polycaprolactone composites for bone tissue engineering application.

    PubMed

    Pan, Lanlan; Pei, Xibo; He, Rui; Wan, Qianbing; Wang, Jian

    2012-05-01

    In this study, the multiwall carbon nanotubes (MWNTs)/polycaprolactone composite scaffolds were fabricated by the solution evaporation technique. The morphology, phase composition and the mechanical properties of the composite scaffolds were characterized and the cellular bioactivity of the scaffolds was assessed by using rat bone-marrow-derived stroma cells (BMSCs). The attachment, proliferation and differentiation of the BMSCs on the composite scaffolds were analyzed by scanning electron microscopy (SEM), 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) nuclear staining and fluorescein diacetate (FDA) and propidium iodide (PI) live/dead staining, methylthiazol tetrazolium (MTT) assay and alkaline phosphatase (ALP) activity assay, respectively. Results showed that mechanical properties of the composite scaffolds were improved with the addition of MWNTs (0.25-2 wt%). BMSCs on the composite scaffolds differentiated down the osteogenic lineage and expressed high levels of bone marker ALP. The scaffolds with low concentration (0.5 wt%) of MWNTs can enhance the proliferation and differentiation of the BMSCs more than that with higher concentration of MWNTs. It is concluded that MWNTs/PCL composite scaffolds have the potential for bone tissue engineering and the relatively low concentration of MWNTs (0.5 wt%) is preferred. PMID:22305638

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

    PubMed Central

    O'Valle, Francisco; Lanis, Alejandro; Dohan Ehrenfest, David M.; Wang, Hom-Lay; Galindo-Moreno, Pablo

    2015-01-01

    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. PMID:26064899

  13. Actinide(IV) Deposits on Bone: Potential Role of the Osteopontin-Thorium Complex.

    PubMed

    Creff, Gaëlle; Safi, Samir; Roques, Jérôme; Michel, Hervé; Jeanson, Aurélie; Solari, Pier-Lorenzo; Basset, Christian; Simoni, Eric; Vidaud, Claude; Den Auwer, Christophe

    2016-01-01

    In case of a nuclear event, contamination (broad or limited) of the population or of specific workers might occur. In such a senario, the fate of actinide contaminants may be of first concern, in particular with regard to human target organs like the skeleton. To improve our understanding of the toxicological processes that might take place, a mechanistic approach is necessary. For instance, ∼50% of Pu(IV) is known from biokinetic data to accumulate in bone, but the underlining mechanisms are almost unknown. In this context, and to obtain a better description of the toxicological mechanisms associated with actinides(IV), we have undertaken the investigation, on a molecular scale, of the interaction of thorium(IV) with osteopontin (OPN) a hyperphosphorylated protein involved in bone turnover. Thorium is taken here as a simple model for actinide(IV) chemistry. In addition, we have selected a phosphorylated hexapeptide (His-pSer-Asp-Glu-pSer-Asp-Glu-Val) that is representative of the peptidic sequence involved in the bone interaction. For both the protein and the biomimetic peptide, we have determined the local environment of Th(IV) within the bioactinidic complex, combining isothermal titration calorimetry, attenuated total reflectance Fourier transform infrared spectroscopy, theoretical calculations with density functional theory, and extended X-ray absorption fine structure spectroscopy at the Th LIII edge. The results demonstrate a predominance of interaction of metal with the phosphate groups and confirmed the previous physiological studies that have highlighted a high affinity of Th(IV) for the bone matrix. Data are further compared with those of the uranyl case, representing the actinyl(V) and actinyl(VI) species. Last, our approach shows the importance of developing simplified systems [Th(IV)-peptide] that can serve as models for more biologically relevant systems. PMID:26684435

  14. A comparative study of zwitterionic ligands-mediated mineralization and the potential of mineralized zwitterionic matrices for bone tissue engineering

    PubMed Central

    Liu, Pingsheng; Emmons, Erin

    2014-01-01

    Cationic and anionic residues of the extracellular matrices (ECM) of bone play synergistic roles in recruiting precursor ions and templating the nucleation, growth and crystalline transformations of calcium apatite in natural biomineralization. We previously reported that zwitterionic sulfobetaine ligands can template extensive 3-dimensional (3-D) hydroxyapaptite (HA)-mineralization of photo-crosslinked polymethacrylatehydrogels. Here, we compared the potency of two other major zwitterionic ligands, phosphobetaine and carboxybetaine, with that of the sulfobetaine in mediating 3-D mineralization using the crosslinked polymethacrylate hydrogel platform. We confirmed that all three zwitterionic hydrogels were able to effectively template 3-D mineralization, supporting the general ability of zwitterions to mediate templated mineralization. Among them, however, sulfobetaine and phosphobetaine hydrogels templated denser 3-D mineralizationthan the carboxybetaine hydrogel, likely due to their higher free water fractions and better maintenance of zwitterionic nature throughout the pH-changes during the in vitro mineralization process. We further demonstrated that the extensively mineralized zwitterionic hydrogels could be exploited for efficient retention (e.g. 99% retention after 24-h incubation in PBS) of osteogenic growth factor recombinant bone morphogenetic protein-2 (rhBMP-2) and subsequent sustained local release with retained bioactivity. Combined with the excellent cytocompatibility of all three zwitterionic hydrogels and the significantly improved cell adhesive properties of their mineralized matrices, these materials could find promising applications in bone tissue engineering. PMID:25558374

  15. Clinical Applications of S53P4 Bioactive Glass in Bone Healing and Osteomyelitic Treatment: A Literature Review

    PubMed Central

    van Gestel, N. A. P.; Geurts, J.; Hulsen, D. J. W.; van Rietbergen, B.; Hofmann, S.; Arts, J. J.

    2015-01-01

    Nowadays, S53P4 bioactive glass is indicated as a bone graft substitute in various clinical applications. This review provides an overview of the current published clinical results on indications such as craniofacial procedures, grafting of benign bone tumour defects, instrumental spondylodesis, and the treatment of osteomyelitis. Given the reported results that are based on examinations, such as clinical examinations by the surgeons, radiographs, CT, and MRI images, S53P4 bioactive glass may be beneficial in the various reported applications. Especially in craniofacial reconstructions like mastoid obliteration and orbital floor reconstructions, in grafting bone tumour defects, and in the treatment of osteomyelitis very promising results are obtained. Randomized clinical trials need to be performed in order to determine whether bioactive glass would be able to replace the current golden standard of autologous bone usage or with the use of antibiotic containing PMMA beads (in the case of osteomyelitis). PMID:26504821

  16. Bone marrow microenvironment in myelomagenesis: its potential role in early diagnosis

    PubMed Central

    Balakumaran, Arun; Robey, Pamela Gehron; Fedarko, Neal; Landgren, Ola

    2010-01-01

    Multiple myeloma (MM) is the second most common hematological malignancy, with an overall survival of 4–6 years. It is always preceded by a premalignant stage called monoclonal gammopathy of unknown significance (MGUS). Importantly, at this time we lack reliable predictors to determine who will progress from MGUS to MM, and who will remain stable. The bone marrow microenvironment plays a key role in myelomagenesis (growth, survival and migration of malignant plasma cells). In the present review, we summarize and discuss our current understanding of the bone marrow microenvironment and its compartments in relation to myelomagenesis. Although it remains to be proven, we believe that an improved characterization of the cellular constituents, the extracellular matrix components and the soluble factors of the bone marrow could open up novel avenues to better understand underlying mechanisms of the transformation from MGUS to MM. Ultimately, this will lead to the development of early treatment of high-risk precursor disease aimed to delay/prevent MM. PMID:20465501

  17. Embedded silica nanoparticles in poly(caprolactone) nanofibrous scaffolds enhanced osteogenic potential for bone tissue engineering.

    PubMed

    Ganesh, Nitya; Jayakumar, Rangasamy; Koyakutty, Manzoor; Mony, Ullas; Nair, Shantikumar V

    2012-09-01

    Poly(caprolactone) (PCL) has been frequently considered for bone tissue engineering because of its excellent biocompatibility. A drawback, however, of PCL is its inadequate mechanical strength for bone tissue engineering and its inadequate bioactivity to promote bone tissue regeneration from mesenchymal stem cells. To correct this deficiency, this work investigates the addition of nanoparticles of silica (nSiO(2)) to the scaffold to take advantage of the known bioactivity of silica as an osteogenic material and also to improve the mechanical properties through nanoscale reinforcement of the PCL fibers. The nanocomposite scaffolds and the pristine PCL scaffolds were evaluated physicochemically, mechanically, and biologically in the presence of human mesenchymal stem cells (hMSCs). The results indicated that, when the nanoparticles of size approximately 10 nm (concentrations of 0.5% and 1% w/v) were embedded within, or attached to, the PCL nanofibers, there was a substantial increase in scaffold strength, protein adsorption, and osteogenic differentiation of hMSCs. These nSiO(2) nanoparticles, when directly added to the cells evidently pointed to ingestion of these particles by the cells followed by cell death. The polymer nanofibers appeared to protect the cells by preventing ingestion of the silica nanoparticles, while at the same time adequately exposing them on fiber surfaces for their desired bioactivity. PMID:22725098

  18. Bone quality analysis using X-ray microtomography and microfluorescence.

    PubMed

    Sales, E; Lima, I; de Assis, J T; Gómez, W; Pereira, W C A; Lopes, R T

    2012-07-01

    Bone quality is an evaluation index often applied in order to interpret clinical observations made upon bone health, such as bone mineral density, micro and macro architecture, and mineral content. Conventional inspection techniques do not provide full information on trabecular bone quality. This study shows the high resolution potential and the non-destructive character of X-ray microtomography and microfluorescence upon the application of such techniques for evaluating bone quality. The mineral content assessment was performed by two-dimensional concentration mappings of calcium, zinc, and strontium. The results showed significant changes in bone morphology. PMID:22206910

  19. Advances in the design of macroporous polymer scaffolds for potential applications in dentistry

    PubMed Central

    Braschler, Thomas M.; Renaud, Philippe

    2013-01-01

    A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size, thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissue-engineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications. PMID:24455437

  20. Potential applications of computational fluid dynamics to biofluid analysis

    NASA Technical Reports Server (NTRS)

    Kwak, D.; Chang, J. L. C.; Rogers, S. E.; Rosenfeld, M.; Kwak, D.

    1988-01-01

    Computational fluid dynamics was developed to the stage where it has become an indispensable part of aerospace research and design. In view of advances made in aerospace applications, the computational approach can be used for biofluid mechanics research. Several flow simulation methods developed for aerospace problems are briefly discussed for potential applications to biofluids, especially to blood flow analysis.

  1. A study of stress-free living bone and its application to space flight

    NASA Technical Reports Server (NTRS)

    Leblanc, A.; Spira, M.

    1983-01-01

    Observations of animals and human subjects in weightless space flight (Skylab and COSMOS) document altered bone metabolism. Bone metabolism is affected by a number of local and systemic factors. The calcification and growth of transplanted bone is independent of local muscle, nervous, and mechanical forces; therefore, transplanted bone would provide data on the role of local vs. systematic factors. Bone metabolism in living transplanted bone, devoid of stress, was investigated as a possible tool for the investigation of countermeasures against disuse bone loss. An animal model using Sprague-Dawley rats was developed for transplantation of femur bone tissue on a nutrient vascular pedicel. The long term course of these implants was assessed through the measure of regional and total bone mineral, blood flow, and methylene diphosphonate (MDP) uptake. Clomid, an estrogen agonist/antagonist, was shown to protect bone from disuse loss of minerals by retarding trabecular and cortical resorption.

  2. Comparative study of osteogenic potential of a composite scaffold incorporating either endogenous bone morphogenetic protein-2 or exogenous phytomolecule icaritin: an in vitro efficacy study.

    PubMed

    Chen, S-H; Wang, X-L; Xie, X-H; Zheng, L-Z; Yao, D; Wang, D-P; Leng, Y; Zhang, G; Qin, L

    2012-08-01

    A local delivery system with sustained and efficient release of therapeutic agents from an appropriate carrier is desirable for orthopedic applications. Novel composite scaffolds made of poly (lactic-co-glycolic acid) with tricalcium phosphate (PLGA/TCP) were fabricated by an advanced low-temperature rapid prototyping technique, which incorporated either endogenous bone morphogenetic protein-2 (BMP-2) (PLGA/TCP/BMP-2) or phytomolecule icaritin (ICT) (PLGA/TCP/ICT) at low, middle and high doses. PLGA/TCP served as control. In vitro degradation, osteogenesis and release tests showed statistical differences among PLGA/TCP/ICT, PLGA/TCP and PLGA/TCP/BMP-2 groups, where PLGA/TCP/ICT had the desired slow release of bioactive icaritin in a dose-dependent manner, whereas there was almost no BMP-2 release from the PLGA/TCP/BMP-2 scaffolds. PLGA/TCP/ICT significantly increased more ALP activity, upregulated mRNA expression of osteogenic genes and enhanced calcium deposition and mineralization in rabbit bone marrow stem cells cultured on scaffolds compared with the other two groups. These results indicate the desired degradation rate, osteogenic capability and release property in PLGA/TCP/ICT composite scaffold, as icaritin preserved its bioactivity and structure after incorporation, while PLGA/TCP/BMP-2 did not show an initially expected osteogenic potential, owing to loss of the original bioactivity of BMP-2 during its incorporation and fabrication procedure. The results suggest that PLGA/TCP composite scaffolds incorporating osteogenic ICT might be a promising approach for bone tissue bioengineering and regeneration. PMID:22543006

  3. Investigation of potential interaction of ciprofloxacin with cyclosporine in bone marrow transplant recipients.

    PubMed Central

    Krüger, H U; Schuler, U; Proksch, B; Göbel, M; Ehninger, G

    1990-01-01

    The effect of the 4-quinolone antimicrobial agent ciprofloxacin on the concentration in plasma and the pharmacokinetics of the immunosuppressive agent cyclosporine was studied in 10 bone marrow transplant recipients. There were no statistically or clinically significant changes in cyclosporine trough concentrations or areas under the concentration-time curve following oral doses of 500 mg of ciprofloxacin every 12 h for 4 days. The data suggest a lack of relevant pharmacokinetic interaction of ciprofloxacin with cyclosporine. There was no indication of an enhanced nephrotoxicity for this drug combination. PMID:2203301

  4. Brown tumor of bone: A potential source of false-positive thallium-201 localization

    SciTech Connect

    Yang, C.J.; Seabold, J.E.; Gurll, N.J.

    1989-07-01

    Brown tumor of bone (osteitis fibrosa cystica) should be included in the differential diagnosis of lesions that cause false-positive thallium-201 localization in patients with primary hyperparathyroidism. We report a case of a brown tumor of the upper sternum mimicking a superior mediastinal parathyroid neoplasm in a patient with persistent hyperparathyroidism 9 years after a negative neck exploration (with subtotal thyroidectomy and thymectomy). A /sup 201/TI//sup 99m/Tc pertechnetate subtraction scintigram demonstrated complete subtraction of this /sup 201/TI focus.

  5. Impact of prophylactic CpG Oligodeoxynucleotide application on implant-associated Staphylococcus aureus bone infection.

    PubMed

    Sethi, Shneh; Thormann, Ulrich; Sommer, Ursula; Stötzel, Sabine; Mohamed, Walid; Schnettler, Reinhard; Domann, Eugen; Chakraborty, Trinad; Alt, Volker

    2015-09-01

    TLR-9 ligand CpG oligodeoxynucleotide type B (CpG ODN) induces a proinflammatory environment. We evaluated the effects of a preoperative CpG ODN application in an implant-associated Staphylococcus aureus bone infection model by monitoring bacterial loads and cytokine and chemokine levels. A total of 95 rats were used in four different groups: CpG ODN group (group 1; n=25), non-CpG-ODN group (group 2; n=25); saline pretreatment (group 3; n=25), and one uninfected group (group 4; n=20). A single dose of CpG-ODN was administered to the left tibialis anterior muscle 3days prior to surgery and the tibia midshaft was osteotomized, stabilized by an intramedullary implant and subsequently contaminated with 10(3) colony forming units (CFUs) of S. aureus in groups 1-3. The osteotomy gap in animals of group 4 was not contaminated with S. aureus and those animals did not receive any pretreatment. CpG ODN administration resulted in significant reduction of the bacterial load in tibia tissue homogenate and on the implant surface on day 1 post-infection compared to non-CpG-ODN pretreatment (p<0.05; p<0.05). Reductions in bacterial CFUs, compared to non-treated (saline) controls, were approximately 67% and 77% for bone tissue homogenates and implants. No bacteria were detected in uninfected rats. Early reduction of bacterial CFUs in the tibia was accompanied by increased levels of proinflammatory mediators MIP-2, IL-1β and RANTES in bone tissue milieu of the CpG ODN treated group compared to controls. At day 42 post-infection, bone marrow tissue of rats pretreated with CpG ODN had comparable high bacterial CFU numbers as the non-CpG ODN or saline treated groups. Microbiological analysis of implants removed from CpG ODN treated rats showed high bacterial growth densities on their surfaces which were not different from those observed in controls. In histology, all animals of groups 1-3 showed established infected non-unions. Additionally, inflammatory mediator profiles in bone

  6. Potential geothermal energy applications for Idaho Elks Rehabilitation Hospital

    SciTech Connect

    Austin, J.C.

    1981-11-01

    Several potential applications of geothermal energy for the Idaho Elks Rehabilitation Hospital are outlined. A brief background on the resource and distribution system, is provided; which hospital heating systems should be considered for potential geothermal retrofit is discussed; and technical and economic feasibility are addressed.

  7. Preparation and evaluation of an Arg-Gly-Asp-modified chitosan/hydroxyapatite scaffold for application in bone tissue engineering

    PubMed Central

    CHEN, LIN; LI, BAOLIN; XIAO, XIAO; MENG, QINGGANG; LI, WEI; YU, QIAN; BI, JIAQI; CHENG, YONG; QU, ZHIWEI

    2015-01-01

    Bone tissue engineering has become a promising method for the repair of bone defects, and the production of a scaffold with high cell affinity and osseointegrative properties is crucial for successful bone substitute. Chitosan (CS)/hydroxyapatite (HA) composite was prepared by in situ compositing combined with lyophilization, and further modified by arginine-glycine-aspartic acid (RGD) via physical adsorption. In order to evaluate the cell adhesion rate, viability, morphology, and alkaline phosphatase (ALP) activity, the RGD-CS/HA scaffold was seeded with bone marrow stromal cells (BMSCs). The osseointegrative properties of the RGD-CS/HA scaffold were evaluated by in vivo heterotopic ossification and in vivo bone defect repair. After 4 h culture with the RGD-CS/HA scaffold, the adhesion rate of the BMSCs was 80.7%. After 3 days, BMSCs were fusiform in shape and evenly distributed on the RGD-CS/HA scaffold. Formation of extracellular matrix and numerous cell-cell interactions were observed after 48 h of culture, with an ALP content of 0.006±0.0008 U/l/ng. Furthermore, the osseointegrative ability and biomechanical properties of the RGD-CS/HA scaffold were comparable to that of normal bone tissue. The biocompatibility, cytocompatibility, histocompatibility and osseointegrative properties of the RGD-CS/HA scaffold support its use in bone tissue engineering applications. PMID:26459053

  8. Preparation and evaluation of an Arg-Gly-Asp-modified chitosan/hydroxyapatite scaffold for application in bone tissue engineering.

    PubMed

    Chen, Lin; Li, Baolin; Xiao, Xiao; Meng, Qinggang; Li, Wei; Yu, Qian; Bi, Jiaqi; Cheng, Yong; Qu, Zhiwei

    2015-11-01

    Bone tissue engineering has become a promising method for the repair of bone defects, and the production of a scaffold with high cell affinity and osseointegrative properties is crucial for successful bone substitute. Chitosan (CS)/hydroxyapatite (HA) composite was prepared by in situ compositing combined with lyophilization, and further modified by arginine‑glycine‑aspartic acid (RGD) via physical adsorption. In order to evaluate the cell adhesion rate, viability, morphology, and alkaline phosphatase (ALP) activity, the RGD‑CS/HA scaffold was seeded with bone marrow stromal cells (BMSCs). The osseointegrative properties of the RGD‑CS/HA scaffold were evaluated by in vivo heterotopic ossification and in vivo bone defect repair. After 4 h culture with the RGD‑CS/HA scaffold, the adhesion rate of the BMSCs was 80.7%. After 3 days, BMSCs were fusiform in shape and evenly distributed on the RGD‑CS/HA scaffold. Formation of extracellular matrix and numerous cell‑cell interactions were observed after 48 h of culture, with an ALP content of 0.006 ± 0.0008 U/l/ng. Furthermore, the osseointegrative ability and biomechanical properties of the RGD‑CS/HA scaffold were comparable to that of normal bone tissue. The biocompatibility, cytocompatibility, histocompatibility and osseointegrative properties of the RGD‑CS/HA scaffold support its use in bone tissue engineering applications. PMID:26459053

  9. In vitro and in vivo degradation evaluation of novel iron-bioceramic composites for bone implant applications.

    PubMed

    Ulum, M F; Arafat, A; Noviana, D; Yusop, A H; Nasution, A K; Abdul Kadir, M R; Hermawan, H

    2014-03-01

    Biodegradable metals such as magnesium, iron and their alloys have been known as potential materials for temporary medical implants. However, most of the studies on biodegradable metals have been focusing on optimizing their mechanical properties and degradation behavior with no emphasis on improving their bioactivity behavior. We therefore investigated the possibility of improving iron biodegradation rate and bioactivity by incorporating various bioactive bioceramics. The iron-based bioceramic (hydroxyapatite, tricalcium phosphate and biphasic calcium phosphate) composites were prepared by mechanical mixing and sintering process. Degradation studies indicated that the addition of bioceramics lowered the corrosion potential of the composites and slightly increased their corrosion rate compared to that of pure iron. In vitro cytotoxicity results showed an increase of cellular activity when rat smooth muscle cells interacted with the degrading composites compared to pure iron. X-ray radiogram analysis showed a consistent degradation progress with that found in vivo and positive tissue response up to 70 days implantation in sheep animal model. Therefore, the iron-based bioceramic composites have the potential to be used for biodegradable bone implant applications. PMID:24433920

  10. Hydrogen gas treatment prolongs replicative lifespan of bone marrow multipotential stromal cells in vitro while preserving differentiation and paracrine potentials

    SciTech Connect

    Kawasaki, Haruhisa; Guan, Jianjun; Tamama, Kenichi

    2010-07-02

    Cell therapy with bone marrow multipotential stromal cells/mesenchymal stem cells (MSCs) represents a promising approach in the field of regenerative medicine. Low frequency of MSCs in adult bone marrow necessitates ex vivo expansion of MSCs after harvest; however, such a manipulation causes cellular senescence with loss of differentiation, proliferative, and therapeutic potentials of MSCs. Hydrogen molecules have been shown to exert organ protective effects through selective reduction of hydroxyl radicals. As oxidative stress is one of the key insults promoting cell senescence in vivo as well as in vitro, we hypothesized that hydrogen molecules prevent senescent process during MSC expansion. Addition of 3% hydrogen gas enhanced preservation of colony forming early progenitor cells within MSC preparation and prolonged the in vitro replicative lifespan of MSCs without losing differentiation potentials and paracrine capabilities. Interestingly, 3% hydrogen gas treatment did not decrease hydroxyl radical, protein carbonyl, and 8-hydroxydeoxyguanosine, suggesting that scavenging hydroxyl radical might not be responsible for these effects of hydrogen gas in this study.

  11. Growth and Potential Damage of Human Bone-Derived Cells Cultured on Fresh and Aged C60/Ti Films

    PubMed Central

    Kopova, Ivana; Lavrentiev, Vasily; Vacik, Jiri; Bacakova, Lucie

    2015-01-01

    Thin films of binary C60/Ti composites, with various concentrations of Ti ranging from ~ 25% to ~ 70%, were deposited on microscopic glass coverslips and were tested for their potential use in bone tissue engineering as substrates for the adhesion and growth of bone cells. The novelty of this approach lies in the combination of Ti atoms (i.e., widely used biocompatible material for the construction of stomatological and orthopedic implants) with atoms of fullerene C60, which can act as very efficient radical scavengers. However, fullerenes and their derivatives are able to generate harmful reactive oxygen species and to have cytotoxic effects. In order to stabilize C60 molecules and to prevent their possible cytotoxic effects, deposition in the compact form of Ti/C60 composites (with various Ti concentrations) was chosen. The reactivity of C60/Ti composites may change in time due to the physicochemical changes of molecules in an air atmosphere. In this study, we therefore tested the dependence between the age of C60/Ti films (from one week to one year) and the adhesion, morphology, proliferation, viability, metabolic activity and potential DNA damage to human osteosarcoma cells (lines MG-63 and U-2 OS). After 7 days of cultivation, we did not observe any negative influence of fresh or aged C60/Ti layers on cell behavior, including the DNA damage response. The presence of Ti atoms resulted in improved properties of the C60 layers, which became more suitable for cell cultivation. PMID:25875338

  12. Osteogenic differentiation of human bone marrow mesenchymal stem cells seeded on melt based chitosan scaffolds for bone tissue engineering applications.

    PubMed

    Costa-Pinto, Ana R; Correlo, Vitor M; Sol, Paula C; Bhattacharya, Mrinal; Charbord, Pierre; Delorme, Bruno; Reis, Rui L; Neves, Nuno M

    2009-08-10

    The purpose of this study was to evaluate the growth patterns and osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) when seeded onto new biodegradable chitosan/polyester scaffolds. Scaffolds were obtained by melt blending chitosan with poly(butylene succinate) in a proportion of 50% (wt) each and further used to produce a fiber mesh scaffold. hBMSCs were seeded on those structures and cultured for 3 weeks under osteogenic conditions. Cells were able to reduce MTS and demonstrated increasing metabolic rates over time. SEM observations showed cell colonization at the surface as well as within the scaffolds. The presence of mineralized extracellular matrix (ECM) was successfully demonstrated by peaks corresponding to calcium and phosphorus elements detected in the EDS analysis. A further confirmation was obtained when carbonate and phosphate group peaks were identified in Fourier Transformed Infrared (FTIR) spectra. Moreover, by reverse transcriptase (RT)-PCR analysis, it was observed the expression of osteogenic gene markers, namely, Runt related transcription factor 2 (Runx2), type 1 collagen, bone sialoprotein (BSP), and osteocalcin. Chitosan-PBS (Ch-PBS) biodegradable scaffolds support the proliferation and osteogenic differentiation of hBMSCs cultured at their surface in vitro, enabling future in vivo testing for the development of bone tissue engineering therapies. PMID:19621927

  13. Irradiation alters the differentiation potential of bone marrow mesenchymal stem cells

    PubMed Central

    WANG, YU; ZHU, GUOYING; WANG, JIANPING; CHEN, JUNXIANG

    2016-01-01

    Bone injury following radiotherapy has been confirmed by epidemiological and animal studies. However, the underlying mechanism remains to be elucidated and no preventive or curative solution has been identified for this bone loss. The present study aimed to investigate the irradiation-altered osteogenesis and adipogenesis of bone marrow mesenchymal stem cells (BMSCs). BMSCs were derived and exposed to γ-irradiation at doses of 0, 0.25, 0.5, 1, 2, 5 and 10 Gy. Cell viability was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay, and clonal expansion in vitro was detected by colony forming unit assessment. The osteogenic differentiation ability was demonstrated by alkaline phosphatase (ALP) activity, ALP staining and mineralization alizarin red staining, and the adipogenic differentiation ability was determined using Oil O red staining. The osteogenesis-associated genes, RUNX2, ALP, osteocalcin (OCN) and adipogenesis-associated genes, PPAR-γ and C/EBPα, were detected using reverse transcription-quantitative polymerase chain reaction analyses. The protein expression levels of RUNX2, ALP and PPAR-γ were detected using western blotting. Compared with the control, significant decreases in the proliferation, ALP activity and mineralization ability of the BMSCs were observed in the γ-irradiation group, with a high level of correlation with the exposure dose. However, no significant changes were observed in the area of Oil red O positive staining. The mRNA levels of RUNX2, ALP and OCN were decreased (P<0.05), however, no significant changes were observed in the levels of C/EBPα and PPAR-γ. The protein expression levels of RUNX2 and ALP were decreased in the irradiated BMSCs, however, no significant difference was observed in the protein expression of PPAR-γ. Irradiation inhibited the osteogenic and adipogenic ability of the BMSCs, and the osteogenic differentiation was decreased. The results of the present study provided evidence

  14. Effects of Cryopreservation on the Cell Viability, Proliferative Capacity and Neuronal Differentiation Potential of Canine Bone Marrow Stromal Cells

    PubMed Central

    EDAMURA, Kazuya; NAKANO, Rei; FUJIMOTO, Kyohei; TESHIMA, Kenji; ASANO, Kazushi; TANAKA, Shigeo

    2013-01-01

    ABSTRACT We investigated the cell viability, proliferative capacity and neuronal differentiation potential of canine bone marrow stromal cells (BMSCs) after cryopreservation. BMSCs were cryopreserved using cryoprotectant solutions with 10% DMSO and 10% FBS (DF group) or without DMSO and FBS (DF-free group); fresh BMSCs were used as a control. The cell viability and proliferative capacity of BMSCs were similar in the DF-free and control groups, while those in the DF group were lower. In all groups, BMSCs differentiated into neuron-like cells that stained positive against neuron markers, and the mRNA expression levels of neuron markers increased after neuronal induction. In conclusion, cryopreservation with DF-free cryoprotectant solution did not diminish the cell viability, proliferative capacity or neuronal differentiation potential of canine BMSCs. PMID:24334862

  15. Microvascular anastomoses for bone grafts in the treatment of massive defects in bone.

    PubMed

    Weiland, A J; Daniel, R K

    1979-01-01

    Six patients with large defects in bone are described in whom we performed microvascular anastomoses of grafted fibular vessels (arteries and veins) to vessels in the recipient site. Two other patients, with massive loss of bone and skin, were treated by grafting of osteocutaneous composites also using microvascular anastomoses. All but one defect healed successfully. There is a wide potential for applications of these two techniques in the treatment of large segmental bone defects secondary to trauma or following tumor resection. PMID:365868

  16. Potential role of proprotein convertase SKI-1 in the mineralization of primary bone.

    PubMed

    Gorski, Jeff P; Huffman, Nichole T; Cui, Chaoying; Henderson, Ellen P; Midura, Ronald J; Seidah, Nabil G

    2009-01-01

    The biochemical mechanism controlling nucleation of mineral crystals in developing bone, along with the growth and propagation of these crystals once formed, remains poorly understood. To define the nucleation mechanism, a proteomics analysis was begun on isolated biomineralization foci (BMF), sites of initial crystal nucleation in osteoblastic cell cultures and in primary bone. Comparative analyses of the protein profile for mineralized BMF with that for total osteoblast cultures revealed the latter were enriched in several proteins including BAG-75 and BSP, as well as fragments of each. When 12 protease inhibitors were added separately to UMR 106-01 osteoblastic cultures, only the serine protease inhibitor 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF) blocked cleavage of BAG-75 and BSP, and prevented mineral crystal nucleation within BMF. Consideration of the specificities of the inhibitors tested and the fact that AEBSF inhibition was not dependent upon inclusion of FBS in the culture media indicated that mineral nucleation does not require serine protease plasmin, thrombin, kallikrein, urokinase, C1s or furin. In contrast, SKI-1 (S1P or site-1) is a membrane-bound serine protease inhibitable by AEBSF. We show here for the first time that mineralizing UMR 106 cells express a 98-kDa active, soluble form of SKI-1 within BMF. In contrast, nonmineralizing UMR cells appear to differentially process SKI-1 into smaller immunoreactive fragments (<35 kDa). These findings suggest that SKI-1 plays a direct or indirect role in assembly of functional nucleation complexes containing BAG-75 and BSP and their fragments, thus facilitating initial mineral nucleation within these biomineralization foci. PMID:18728345

  17. Erythropoietin is involved in the angiogenic potential of bone marrow macrophages in multiple myeloma.

    PubMed

    De Luisi, Annunziata; Binetti, Laura; Ria, Roberto; Ruggieri, Simona; Berardi, Simona; Catacchio, Ivana; Racanelli, Vito; Pavone, Vincenzo; Rossini, Bernardo; Vacca, Angelo; Ribatti, Domenico

    2013-10-01

    Erythropoietin (Epo) is the crucial cytokine regulator of red blood cell production, and recombinant human erythropoietin (rHuEpo) is widely used in clinical practice for the treatment of anemia, primarily in kidney disease and in cancer. Increasing evidence suggests several biological roles for Epo and its receptor, Epo-R, unrelated to erythropoiesis, including angiogenesis. Epo-R has been found expressed in various non-haematopoietic cells and tissues, and in cancer cells. Here, we detected the expression of Epo-R in bone marrow-derived macrophages (BMMAs) from multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) patients and assessed whether Epo/Epo-R axis plays a role in MM macrophage-mediated angiogenesis. We found that Epo-R is over-expressed in BMMAs from MM patients with active disease compared to MGUS patients. The treatment of BMMAs with rHuEpo significantly increased the expression and secretion of key pro-angiogenic mediators, such as vascular endothelial growth factor, hepatocyte growth factor and monocyte chemotactic protein (MCP-1/CCL-2), through activation of JAK2/STAT5 and PI3 K/Akt pathways. In addition, the conditioned media harvested from rHuEpo-treated BMMAs enhanced bone marrow-derived endothelial cell migration and capillary morphogenesis in vitro, and induced angiogenesis in the chorioallantoic membrane of chick embryos in vivo. Furthermore, we found an increase in the circulating levels of several pro-angiogenic cytokines in serum of MM patients with anemia under treatment with Epo. Our findings highlight the direct effect of rHuEpo on macrophage-mediated production of pro-angiogenic factors, suggesting that Epo/Epo-R pathway may be involved in the regulation of angiogenic response occurring in MM. PMID:23881169

  18. Application of perfusion culture system improves in vitro and in vivo osteogenesis of bone marrow-derived osteoblastic cells in porous ceramic materials.

    PubMed

    Wang, Yichao; Uemura, Toshimasa; Dong, Jian; Kojima, Hiroko; Tanaka, Junzo; Tateishi, Tetsuya

    2003-12-01

    Composites of bone marrow-derived osteoblasts (BMOs) and porous ceramics have been widely used as a bone graft model for bone tissue engineering. Perfusion culture has potential utility for many cell types in three-dimensional (3D) culture. Our hypothesis was that perfusion of medium would increase the cell viability and biosynthetic activity of BMOs in porous ceramic materials, which would be revealed by increased levels of alkaline phosphate (ALP) activity and osteocalcin (OCN) and enhanced bone formation in vivo. For testing in vitro, BMO/beta-tricalcium phosphate composites were cultured in a perfusion container (Minucells and Minutissue, Bad Abbach, Germany) with fresh medium delivered at a rate of 2 mL/h by a peristaltic pump. The ALP activity and OCN content of composites were measured at the end of 1, 2, 3, and 4 weeks of subculture. For testing in vivo, after subculturing for 2 weeks, the composites were subcutaneously implanted into syngeneic rats. These implants were harvested 4 or 8 weeks later. The samples then underwent a biochemical analysis of ALP activity and OCN content and were observed by light microscopy. The levels of ALP activity and OCN in the composites were significantly higher in the perfusion group than in the control group (p < 0.01), both in vitro and in vivo. Histomorphometric analysis of the hematoxylin- and eosin-stained sections revealed a higher average ratio of bone to pore in BMO/beta-TCP composites of the perfusion group after implantation: 47.64 +/- 6.16 for the perfusion group and 26.22 +/- 4.84 for control at 4 weeks (n = 6, p < 0.01); 67.97 +/- 3.58 for the perfusion group and 47.39 +/- 4.10 for control at 8 weeks (n = 6, p < 0.05). These results show that the application of a perfusion culture system during the subculture of BMOs in a porous ceramic scaffold is beneficial to their osteogenesis. After differentiation culture in vitro with the perfusion culture system, the activity of the osteoblastic cells and the

  19. The anterior maxilla as a potential source of bone grafts: a morphometric cone beam computed tomography analysis of different anatomical areas.

    PubMed

    Bernades Mayordomo, R; Guijarro Martínez, R; Hernández Alfaro, F

    2016-08-01

    The aim of this research was to use cone beam computed tomography (CBCT) to analyze the volume, density, and morphology of the bone available in the anterior region of the maxilla, in order to investigate its potential as a source of bone grafts. Three independent zones were evaluated: the palatine process of the maxilla (PPM), anterior nasal spine (ANS), and subnasal bone (SN). The latter was analyzed bilaterally (SNR, SNL). One hundred CBCT scans were evaluated. The morphometric analysis comprised volumetric and subsequent automatic density calculations, as well as linear measurements. Potential correlations among these parameters, including demographic characteristics, were investigated. The study comprised 52 women and 48 men (mean age 49.6±14.5 years). The calculated bone volume averaged 2.41±0.72cm(3) for PPM, 0.46±0.16cm(3) for ANS, 0.58±0.2cm(3) for SNR, and 0.57±0.21cm(3) for SNL. The anterior region of the maxilla can provide a considerable amount of bone volume from different anatomical zones and should be regarded as a potential donor site for the regeneration of maxillary atrophic bones. Further investigation is required before these findings can be applied in the routine clinical setting. PMID:26993106

  20. Reverse micelle mediated synthesis, processing, mechanical and biological characterization of hydroxyapatite nanopowders for bone graft application

    NASA Astrophysics Data System (ADS)

    Banerjee, Ashis

    Hydroxyapatite (HA) is the most widely used bioceramic material in bone graft applications because of its compositional similarity with natural bone. However, synthetic HA does not show similar mechanical and biological properties to the inorganic component of bone. Properties of ceramic material depend on starting materials, processing techniques, densification and microstructure of the final product. The objective of this research was to process HA whisker reinforced HA composite using HA nanopowders and whiskers. HA nanopowders with different length scale and morphology were synthesized by reverse micelle system using NP5 and NP12 as surfactants and cyclohexane as organic solvent. The lowest average aspect ratio was 1.357+/-0.39 with average particle size of 66 nm and the highest average aspect ratio was 7.277+/-3.227 with average length of 150 nm and width of 20 nm, were synthesized. Micron sized HA whiskers with aspect ratio between 20 and 50, average particle length of 15 mum and width of 400 nm was synthesized using urea as a precipitating agent. Desired microstructure was obtained after sintering with spherical HA nanopowder and whiskers along with dopants. Addition of whiskers decreased density of the sintered compacts. However, at 10 wt% whisker content sample showed microhardness and fracture toughness of 3.6 GPa and 1.5 MPa.m1/2, respectively, and a compressive strength of 80 MPa was obtained. Mineralization study in simulated body fluid (SBF) showed formation of apatite layer on the dense HA compacts indicating a good tendency of bond formation with natural bone. Cytotoxicity results showed excellent cell attachment on the HA surface. In the Appendices, 3 journal articles have been attached which describe synthesis, processing and characterization of undoped and doped PZT nanopowders. Free standing and agglomerated PZT nanopowders were synthesized by the sucrose templated method and the citrate nitrate autocombustion method. Particle size in the range

  1. Bioactive calcium sulfate/magnesium phosphate cement for bone substitute applications.

    PubMed

    Yang, Guangyong; Liu, Jianli; Li, Fan; Pan, Zongyou; Ni, Xiao; Shen, Yue; Xu, Huazi; Huang, Qing

    2014-02-01

    A novel calcium sulfate/magnesium phosphate cement (CSMPC) composite was prepared and studied in the present work. The physical properties including the phases, the microstructures, the setting properties and the compressive strengths of the CSMPCs were studied. The bio-performances of the CSMPCs were comprehensively evaluated using in vitro simulated body fluid (SBF) method and in vitro cell culture. The dependence of the physical and chemical properties of the CSMPC on its composition and microstructure was studied in detail. It is found that the CSMPC composites exhibited mediate setting times (6-12 min) compared to the calcium sulfate (CS) and the magnesium phosphate cement (MPC). They showed an encapsulation structure in which the unconverted hexagonal prism CSH particles were embedded in the xerogel-like MPC matrix. The phase compositions and the mechanical properties of the CSMPCs were closely related to the content of MPC and the hardening process. The CSMPCs exhibited excellent bioactivity and good biocompatibility to support the cells to attach and proliferate on the surface. The CSMPC composite has the potential to serve as bone grafts for the bone regeneration. PMID:24411353

  2. Evaluation of potential military applications of stirling engines

    NASA Astrophysics Data System (ADS)

    Oelrich, Ivan C.; Riddell, Frederick R.

    1988-07-01

    This paper reports on the potential military applications of the Stirling engine. In the applications considered here, the major advantages cited for the Stirling engine are multifuel capability, efficiency, and low noise levels. These potential advantages are small compared to current diesels. Diesels are already able to burn broadcut fuels, have high efficiency, and can be adequately muffled. Their major disadvantages are size, weight, and cost. These disadvantages are only severe in vehicular and mobile power applications where the competition is open-cycle internal combustion engines (diesel, spark-ignition, or turbine). In underwater and space power applications where closed-cycle engines are a necessity, the use of Stirling engines shows more promise.

  3. Cell biological effects of mechanical stimulations generated by focused extracorporeal shock wave applications on cultured human bone marrow stromal cells.

    PubMed

    Suhr, Frank; Delhasse, Yvonne; Bungartz, Gerd; Schmidt, Annette; Pfannkuche, Kurt; Bloch, Wilhelm

    2013-09-01

    Human bone marrow stromal cells (hBMSCs) bear tremendous clinical potential due to their immunomodulatory properties in transplantation settings and their contribution to tissue regeneration. In fact, they are among the most promising types of stem-like cells for therapeutic applications and are the subject of intense research. However, the clinical use of hBMSCs has been confounded by limitations in their availability; they are scarce cells cumbersome to isolate and purify. Additionally, they are difficult to target to the site of injury in regeneration experiments. In order to combat these limitations, focused extracorporeal shock waves (fESW, 0.2/0.3mJ∗mm(-2)) were applied to purified, cultured hBMSCs. fESW (0.2mJ∗mm(-2)) stimulations were found to increase hBMSCs' growth rate (p<0.05), proliferation (p<0.05), migration, cell tracking and wound healing (p<0.05, respectively), as well as to reduce the rate of apoptosis activation (p<0.05). The increase in hBMSC migration behavior was found to be mediated by active remodeling of the actin cytoskeleton as indicated by increased directed stress fiber formations (p<0.05). Furthermore, hBMSCs maintain their differentiation potentials after fESW treatment, whereas 0.2mJ∗mm(-2) is the most effective application. In conclusion, our results establish first-timely that hBMSCs' behavior can be modified and optimized in response to defined mechanical stimulation. These findings appear particularly promising as they suggest that mechanical stress preconditions hBMSCs for improved therapeutic performance without genetic manipulations and that mechanically preconditioned hBMSCs will be advantageous for hBMSC-based tissue regeneration. Therefore, this approach opens the door for exploiting the full potential of these cells in regenerative medicine. PMID:23880536

  4. Potential applications for artificial intelligence in the petroleum industry

    SciTech Connect

    Alegre, L. )

    1991-11-01

    This article clarifies some concepts of artificial intelligence (AI), discusses some of its applications, and demonstrates its potential application in the petroleum industry. AI is divided into two levels: the psychological, where it attempts to represent knowledge explicitly, and the intuitive, where explication of knowledge is not important and the emphasis is on brain architecture. Expert systems, which implement explicit knowledge, are discussed in more detail. A brief discussion of use of AI in Brazil, particularly at Petrobras, is presented.

  5. Physical and Biological Modification of Polycaprolactone Electrospun Nanofiber by Panax Ginseng Extract for Bone Tissue Engineering Application.

    PubMed

    Pajoumshariati, Seyedramin; Yavari, Seyedeh Kimia; Shokrgozar, Mohammad Ali

    2016-05-01

    Medicinal plants as a therapeutic agent with osteogenic properties can enhance fracture-healing process. In this study, the osteo-inductive potential of Asian Panax Ginseng root extract within electrospun polycaprolactone (PCL) based nanofibers has been investigated. Scanning electron microscopy images revealed that all nanofibers were highly porous and beadles with average diameter ranging from 250 to 650 nm. The incorporation of ginseng extract improved the physical characteristics (i.e., hydrophilicity) of PCL nanofibers, as well as the mechanical properties. Although ginseng extract increased the degradation rate of pure PCL nanofibers, the porous structure and morphology of fibers did not change significantly after 42 days. It was found that nanofibrous scaffolds containing ginseng extract had higher proliferation (up to ~1.5 fold) compared to the pristine PCL. The qRT-PCR analysis demonstrated the addition of ginseng extract into PCL nanofibers induced significant expression of osteogenic genes (Osteocalcin, Runx-2 and Col-1) in MSCs in a concentration dependent manner. Moreover, higher calcium content, alkaline phosphatase activity and higher mineralization of MSCs were observed compared to the pristine PCL fibers. Our results indicated the promising potential of ginseng extract as an additive to enhance osteo-inductivity, mechanical and physical properties of PCL nanofibers for bone tissue engineering application. PMID:26429789

  6. Survey of advanced nuclear technologies for potential applications of sonoprocessing.

    PubMed

    Rubio, Floren; Blandford, Edward D; Bond, Leonard J

    2016-09-01

    Ultrasonics has been used in many industrial applications for both sensing at low power and processing at higher power. Generally, the high power applications fall within the categories of liquid stream degassing, impurity separation, and sonochemical enhancement of chemical processes. Examples of such industrial applications include metal production, food processing, chemical production, and pharmaceutical production. There are many nuclear process streams that have similar physical and chemical processes to those applications listed above. These nuclear processes could potentially benefit from the use of high-power ultrasonics. There are also potential benefits to applying these techniques in advanced nuclear fuel cycle processes, and these benefits have not been fully investigated. Currently the dominant use of ultrasonic technology in the nuclear industry has been using low power ultrasonics for non-destructive testing/evaluation (NDT/NDE), where it is primarily used for inspections and for characterizing material degradation. Because there has been very little consideration given to how sonoprocessing can potentially improve efficiency and add value to important process streams throughout the nuclear fuel cycle, there are numerous opportunities for improvement in current and future nuclear technologies. In this paper, the relevant fundamental theory underlying sonoprocessing is highlighted, and some potential applications to advanced nuclear technologies throughout the nuclear fuel cycle are discussed. PMID:27400217

  7. Applications of genetic algorithms and neural networks to interatomic potentials

    NASA Astrophysics Data System (ADS)

    Hobday, Steven; Smith, Roger; BelBruno, Joe

    1999-06-01

    Applications of two modern artificial intelligence (AI) techniques, genetic algorithms (GA) and neural networks (NN) to computer simulations are reported. It is shown that the GA are very useful tools for determining the minimum energy structures of clusters of atoms described by interatomic potential functions and generally outperform other optimisation methods for this task. A number of applications are given including covalent, and close packed structures of single or multi-component atomic species. It is also shown that (many body) interatomic potential functions for multi-component systems can be derived by training a specially constructed NN on a variety of structural data.

  8. Biomimetic hydroxyapatite as a new consolidating agent for archaeological bone

    NASA Astrophysics Data System (ADS)

    North, Alexis E.

    Recent studies on calcareous stone and plaster consolidation have demonstrated considerable potential by bio-mimicking the growth of hydroxyapatite (HAP), the main mineralogical constituent of teeth and bone matrix. These initial conservation applications, together with significant fundamental research on the precipitation of HAP for bioengineering and biomedical applications, offer great promise in the use of HAP as a consolidating agent for archaeological bone and other similar materials such as archaeological teeth, ivory, and antler. Experimental research via the controlled application of diammonium phosphate (DAP) precursors to bone flour, modern bone samples, and archaeological bones, indicated the in situ formation of HAP with a simultaneous increase in the cohesiveness of friable bone material, while preserving the bone's physiochemical properties. These preliminary results point towards a promising new method in archaeological conservation.

  9. FACILE SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF CELLULOSE-CHITOSAN-HYDROXYAPATITE COMPOSITE MATERIAL, A POTENTIAL MATERIAL FOR BONE TISSUE ENGINEERING

    PubMed Central

    Mututuvari, Tamutsiwa M.; Harkins, April L.

    2013-01-01

    Hydroxyapatite (HAp) is often used as a bone-implant material because it is biocompatible and osteoconductive. However, HAp possesses poor rheological properties and it is inactive against disease-causing microbes. To improve these properties, we developed a green method to synthesize multifunctional composites containing: (1) cellulose (CEL) to impart mechanical strength; (2) chitosan (CS) to induce antibacterial activity thereby maintaining a microbe-free wound site; and (3) HAp. In this method, CS and CEL were co-dissolved in an ionic liquid (IL) and then regenerated from water. HAp was subsequently formed in situ by alternately soaking [CEL+CS] composites in aqueous solutions of CaCl2 and Na2HPO4. At least 88% of IL used was recovered for reuse by distilling the aqueous washings of [CEL+CS]. The composites were characterized using FTIR, XRD and SEM. These composites retained the desirable properties of their constituents. For example, the tensile strength of the composites was enhanced 1.9X by increasing CEL loading from 20% to 80%. Incorporating CS in the composites resulted in composites which inhibited the growth of both Gram positive (MRSA, S. aureus and VRE) and Gram negative (E. coli and P. aeruginosa) bacteria. These findings highlight the potential use of [CEL+CS+HAp] composites as scaffolds in bone tissue engineering. PMID:23595871

  10. Spectral multigrid methods with applications to transonic potential flow

    NASA Technical Reports Server (NTRS)

    Streett, C. L.; Zang, T. A.; Hussaini, M. Y.

    1983-01-01

    Spectral multigrid methods are demonstrated to be a competitive technique for solving the transonic potential flow equation. The spectral discretization, the relaxation scheme, and the multigrid techniques are described in detail. Significant departures from current approaches are first illustrated on several linear problems. The principal applications and examples, however, are for compressible potential flow. These examples include the relatively challenging case of supercritical flow over a lifting airfoil.

  11. Spectral multigrid methods with applications to transonic potential flow

    NASA Technical Reports Server (NTRS)

    Streett, C. L.; Zang, T. A.; Hussaini, M. Y.

    1985-01-01

    Spectral multigrid methods are demonstrated to be a competitive technique for solving the transonic potential flow equation. The spectral discretization, the relaxation scheme, and the multigrid techniques are described in detail. Significant departures from current approaches are first illustrated on several linear problems. The principal applications and examples, however, are for compressible potential flow. These examples include the relatively challenging case of supercritical flow over a lifting airfoil.

  12. Synchrotron Radiation and Energy Dispersive X-Ray Fluorescence Applications on Elemental Distribution in Human Hair and Bones

    SciTech Connect

    Carvalho, M.L.; Marques, A.F.; Brito, J.

    2003-01-24

    This work is an application of synchrotron microprobe X- Ray fluorescence in order to study elemental distribution along human hair samples of contemporary citizens. Furthermore, X-Ray fluorescence spectrometry is also used to analyse human bones of different historical periods: Neolithic and contemporary subjects. The elemental content in the bones allowed us to conclude about environmental contamination, dietary habits and health status influence in the corresponding citizens. All samples were collected post-mortem. Quantitative analysis was performed for Mn, Fe, Co, Ni, Cu, Zn, Br, Rb, Sr and Pb. Mn and Fe concentration were much higher in bones from pre-historic periods. On the contrary, Pb bone concentrations of contemporary subjects are much higher than in pre-historical ones, reaching 100 {mu}g g-1, in some cases. Very low concentrations for Co, Ni, Br and Rb were found in all the analysed samples. Cu concentrations, allows to distinguish Chalcolithic bones from the Neolithic ones. The distribution of trace elements along human hair was studied for Pb and the obtained pattern was consistent with the theoretical model, based on the diffusion of this element from the root and along the hair. Therefore, the higher concentrations in hair for Pb of contemporary individuals were also observed in the bones of citizens of the same sampling sites. All samples were analysed directly without any chemical treatment.

  13. Sr, Mg cosubstituted HA porous macro-granules: potentialities as resorbable bone filler with antiosteoporotic functions.

    PubMed

    Landi, Elena; Uggeri, Jacopo; Medri, Valentina; Guizzardi, Stefano

    2013-09-01

    Porous macro-granules of nanostructured apatite with Ca ions partially cosubstituted with Mg and Sr ions in different ratios (SrMgHAs), were synthesized at 37°C and compared with Mg and/or Sr free apatites (MgHAs and HA). Strontium improved the Mg substitution extent in the apatite and the chemical-physical and thermal stability of the resulting cosubstituted apatite. Porous macro-granules of 400-600 micron with selected composition were tested for the ionic release in synthetic body fluid and the data were related with the results of preliminary cell investigation in vitro. As compared to the corresponding Sr-free granulate, the SrMgHA could be exploited to prolong the beneficial Mg release during the bone regeneration process. In addition the contemporary in situ supply of Sr, an antiosteoporotic and anticarie ion, could influence the quality of new hard tissues. The ionic multirelease created a more favorable environment for human osteoblasts, demonstrated by a proliferative effect for each dose tested in the range 0.1-10 mg/mL. PMID:23348958

  14. Laser wakefield accelerator based light sources: potential applications and requirements

    SciTech Connect

    Albert, F.; Thomas, A. G.; Mangles, S. P.D.; Banerjee, S.; Corde, S.; Flacco, A.; Litos, M.; Neely, D.; Viera, J.; Najmudin, Z.; Bingham, R.; Joshi, C.; Katsouleas, T.

    2015-01-15

    In this article we review the prospects of laser wakefield accelerators as next generation light sources for applications. This work arose as a result of discussions held at the 2013 Laser Plasma Accelerators Workshop. X-ray phase contrast imaging, X-ray absorption spectroscopy, and nuclear resonance fluorescence are highlighted as potential applications for laser-plasma based light sources. We discuss ongoing and future efforts to improve the properties of radiation from plasma betatron emission and Compton scattering using laser wakefield accelerators for these specific applications.

  15. Properties and potential applications of brominated P-100 carbon fibers

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Gaier, J. R.; Hung, C. C.; Banks, B. A.

    1986-01-01

    A review of the properties and potential applications of bromine-intercalated pitch-based carbon fibers is presented. The dynamics of the intercalation reaction are summarized, and characteristics, such as resistivity, density, and stability, are discussed. In addition, the mechanical and electrical properties of bromine-intercalated fiber-epoxy conposites will be addressed. With conductivities comparable to stainless steel, these brominated carbon fibers may be used in a number of composite applications, such as electromagnetic interference shielding containers, large conductive space structures, lightning strike-tolerant aircraft surfaces, and aircraft deicing applications.

  16. Differentiation Potential of Mesenchymal Stem Cells from Equine Bone Marrow Cultured on Hyaluronic Acid-Chitosan Polyelectrolyte Multilayer Biofilm.

    PubMed

    Listoni, Amanda J; Arruda, Isadora; Maia, Leandro; Barberini, Danielle J; Martins, Ian; Vasconcellos, Fernando C; Landim-Alvarenga, Fernanda C

    2015-01-01

    Nanotechnology techniques have a prominent role in the current technical and scientific scene. The layer-by-layer (LbL) deposition allows obtaining nanostructures with sophisticated multilayer, using a simple, but versatile technique. This procedure, which is used to coat and functionalize surfaces with nanometer- thick films, has applications in bioengineering, medicine, chemistry, materials and chemical engineering among other areas. Chitosan is a biomaterial, coming from the chitin, a very abundant polymer in nature, which has been recently tested as scaffolds. In this experiment we test the hypothesis that the hyaluronic acid-chitosan polyelectrolyte multilayer biofilm would be a good substrate to the adherence of equine mesenchymal stem cells derived from bone marrow. The results showed that these biofilms accelerate the process of cell adhesion on smooth surfaces, allowing a constant cell growth and creating a great option to cover surgical materials. PMID:27125135

  17. Adipose-Derived Stem Cells in Functional Bone Tissue Engineering: Lessons from Bone Mechanobiology

    PubMed Central

    Bodle, Josephine C.; Hanson, Ariel D.

    2011-01-01

    This review aims to highlight the current and significant work in the use of adipose-derived stem cells (ASC) in functional bone tissue engineering framed through the bone mechanobiology perspective. Over a century of work on the principles of bone mechanosensitivity is now being applied to our understanding of bone development. We are just beginning to harness that potential using stem cells in bone tissue engineering. ASC are the primary focus of this review due to their abundance and relative ease of accessibility for autologous procedures. This article outlines the current knowledge base in bone mechanobiology to investigate how the knowledge from this area has been applied to the various stem cell-based approaches to engineering bone tissue constructs. Specific emphasis is placed on the use of human ASC for this application. PMID:21338267

  18. Evaluation of In Vivo Osteogenic Potential of Bone Morphogenetic Protein 2-Overexpressing Human Periodontal Ligament Stem Cells Combined with Biphasic Calcium Phosphate Block Scaffolds in a Critical-Size Bone Defect Model.

    PubMed

    Yi, TacGhee; Jun, Choong-Man; Kim, Su Jin; Yun, Jeong-Ho

    2016-03-01

    Human periodontal ligament stem cells (hPDLSCs) are considered potential cellular carriers for gene delivery in the field of tissue regeneration. This study tested the osseoregenerative potential of hPDLSCs transduced with replication-deficient recombinant adenovirus (rAd) containing the gene encoding bone morphogenetic protein-2 (BMP2; hPDLSCs/rAd-BMP2) in both in vivo and in vitro osteogenic environments. After the optimal condition for rAd-mediated transduction was determined, hPDLSCs were transduced to express BMP2. In vivo bone formation was evaluated in a critical-size rat calvarial bone defect model that more closely mimics the harsher in vivo milieu for bone regeneration than subcutaneous transplantation model. As support materials for bone regeneration, block-type biphasic calcium phosphate (BCP) scaffolds were combined with hPDLSCs and/or BMP2 and transplanted into critical-size bone defects in rats. Experimental groups were as follows: BCP scaffold control (group 1 [Gr1]), scaffold containing recombinant human BMP2 (rhBMP2; group 2 [Gr2]), scaffold loaded with normal hPDLSCs (group 3 [Gr3]), scaffold combined with both normal hPDLSCs and rhBMP2 (group 4 [Gr4]), and scaffold loaded with hPDLSCs transduced with rAd-BMP2 (hPDLSCs/rAd-BMP2; group 5 [Gr5]). Our data showed that new bone formation was highest in Gr2. Less mineralization was observed in Gr3, Gr4, and Gr5 in which hPDLSCs were transplanted. In vitro transwell assay demonstrated that hPDLSCs exert an inhibitory activity on BMP2-induced osteogenic differentiation. Our findings suggest that the in vivo bone regenerative potential of BMP2-overexpressing hPDLSCs could be compromised in a critical-size rat calvarial bone defect model. Thus, further investigations are required to elucidate the underlying mechanisms and to develop efficient techniques for improved tissue regeneration. PMID:26825430

  19. Tunable resistive pulse sensing: potential applications in nanomedicine.

    PubMed

    Sivakumaran, Muttuswamy; Platt, Mark

    2016-08-01

    An accurate characterization of nanomaterials used in clinical diagnosis and therapeutics is of paramount importance to realize the full potential of nanotechnology in medicine and to avoid unexpected and potentially harmful toxic effects due to these materials. A number of technical modalities are currently in use to study the physical, chemical and biological properties of nanomaterials but they all have advantages and disadvantages. In this review, we discuss the potential of a relative newcomer, tunable resistive pulse sensing, for the characterization of nanomaterials and its applications in nanodiagnostics. PMID:27480794

  20. [The progress in application of parathyroid hormone in craniomaxillofacial bone regeneration study].

    PubMed

    Chen, X Y; Tang, Z L

    2016-06-01

    Parathyroid hormone(PTH)is synthesized and secreted by chief cell of Gley's glands which possesses dual functions of catabolism and anabolism. It regulates the proliferation and differentiation of multiple cell lines including osteoblast, osteoclast and skeletal lining cells. Furthermore, PTH activates various signaling pathways which control calcium, phosphorous' metabolism and bone conversion, accelerating the bone regeneration and reconstruction. However, the study of PTH in craniomaxillofacial bone regeneration is relatively less and whether the role of parathyroid glands and the mechanism of ossification are consistent with the long bone or not needs further investigation. This review focuses on the progress of PTH in craniomaxillofacial bone regeneration in recent years. PMID:27256534

  1. Motor-Evoked Potential Confirmation of Functional Improvement by Transplanted Bone Marrow Mesenchymal Stem Cell in the Ischemic Rat Brain

    PubMed Central

    Jang, Dong-Kyu; Park, Sang-In; Han, Young-Min; Jang, Kyung-Sool; Park, Moon-Seo; Chung, Young-An; Kim, Min-Wook; Maeng, Lee-So; Huh, Pil-Woo; Yoo, Do-Sung; Jung, Seong-Whan

    2011-01-01

    This study investigated the effect of bone marrow mesenchymal stem cells (BMSCs) on the motor pathway in the transient ischemic rat brain that were transplanted through the carotid artery, measuring motor-evoked potential (MEP) in the four limbs muscle and the atlantooccipital membrane, which was elicited after monopolar and bipolar transcortical stimulation. After monopolar stimulation, the latency of MEP was significantly prolonged, and the amplitude was less reduced in the BMSC group in comparison with the control group (P < .05). MEPs induced by bipolar stimulation in the left forelimb could be measured in 40% of the BMSC group and the I wave that was not detected in the control group was also detected in 40% of the BMSC group. Our preliminary results imply that BMSCs transplanted to the ischemic rat brain mediate effects on the functional recovery of the cerebral motor cortex and the motor pathway. PMID:21772790

  2. The clinical comparative study on high and low viscosity bone cement application in vertebroplasty

    PubMed Central

    Zeng, Teng-Hui; Wang, Yi-Ming; Yang, Xin-Jian; Xiong, Jian-Yi; Guo, Dai-Qi

    2015-01-01

    Objective: To investigate the clinical effect of high and low viscosity bone cement in vertebroplasty for treatment of osteoporotic vertebral compression fractures. Methods: 40 cases of patients with osteoporotic thoracolumbar compression fractures admitted into department of orthopeadics in our hospital were reviewed. All patients were divided into high viscosity bone cement group (20 cases) and low viscosity bone cement group (20 cases). Visual Analog Score (VAS), Oswestry Dability Index (ODI), injured vertebral height restoration (Cobb Angle) and bone cement leakage rate, subsequent fracture rate of vertebrae body with or without surgical treatment were measured. Results: Compared with the low viscosity bone cement group, the VAS score, ODI score and Cobb angle of high viscosity bone cement group had a statistical difference (P<0.05). The postoperative complications in high viscosity bone cement group were lower than those in low viscosity bone cement group (P<0.05). Conclusion: Compared with low viscosity bone cement, bone cement leakage rate reduced obviously in high viscosity bone cement with good clinical effect and prognosis in vertebroplasty for treatment of osteoporotic thoracolumbar compression fractures. PMID:26770507

  3. Recent Developments of Functional Scaffolds for Craniomaxillofacial Bone Tissue Engineering Applications

    PubMed Central

    Kinoshita, Yukihiko; Maeda, Hatsuhiko

    2013-01-01

    Autogenous bone grafting remains a gold standard for the reconstruction critical-sized bone defects in the craniomaxillofacial region. Nevertheless, this graft procedure has several disadvantages such as restricted availability, donor-site morbidity, and limitations in regard to fully restoring the complicated three-dimensional structures in the craniomaxillofacial bone. The ultimate goal of craniomaxillofacial bone reconstruction is the regeneration of the physiological bone that simultaneously fulfills both morphological and functional restorations. Developments of tissue engineering in the last two decades have brought such a goal closer to reality. In bone tissue engineering, the scaffolds are fundamental, elemental and mesenchymal stem cells/osteoprogenitor cells and bioactive factors. A variety of scaffolds have been developed and used as spacemakers, biodegradable bone substitutes for transplanting to the new bone, matrices of drug delivery system, or supporting structures enhancing adhesion, proliferation, and matrix production of seeded cells according to the circumstances of the bone defects. However, scaffolds to be clinically completely satisfied have not been developed yet. Development of more functional scaffolds is required to be applied widely to cranio-maxillofacial bone defects. This paper reviews recent trends of scaffolds for crania-maxillofacial bone tissue engineering, including our studies. PMID:24163634

  4. Targeting survivin as a potential new treatment for chondrosarcoma of bone.

    PubMed

    de Jong, Y; van Oosterwijk, J G; Kruisselbrink, A B; Briaire-de Bruijn, I H; Agrogiannis, G; Baranski, Z; Cleven, A H G; Cleton-Jansen, A-M; van de Water, B; Danen, E H J; Bovée, J V M G

    2016-01-01

    Chondrosarcomas are malignant cartilage-forming bone tumors, which are intrinsically resistant to chemo- and radiotherapy, leaving surgical removal as the only curative treatment option. Therefore, our aim was to identify genes involved in chondrosarcoma cell survival that could serve as a target for therapy. siRNA screening for 51 apoptosis-related genes in JJ012 chondrosarcoma cells identified BIRC5, encoding survivin, as essential for chondrosarcoma survival. Using immunohistochemistry, nuclear as well as cytoplasmic survivin expression was analyzed in 207 chondrosarcomas of different subtypes. Nuclear survivin has been implicated in cell-cycle regulation while cytoplasmic localization is important for its anti-apoptotic function. RT-PCR was performed to determine expression of the most common survivin isoforms. Sensitivity to YM155, a survivin inhibitor currently in phase I/II clinical trial for other tumors, was examined in 10 chondrosarcoma cell lines using viability assay, apoptosis assay and cell-cycle analysis. Survivin expression was found in all chondrosarcoma patient samples. Higher expression of nuclear and cytoplasmic survivin was observed with increasing histological grade in central chondrosarcomas. Inhibition of survivin using YM155 showed that especially TP53 mutant cell lines were sensitive, but no caspase 3/7 or PARP cleavage was observed. Rather, YM155 treatment resulted in a block in S phase in two out of three chondrosarcoma cell lines, indicating that survivin is more involved in cell-cycle regulation than in apoptosis. Thus, survivin is important for chondrosarcoma survival and chondrosarcoma patients might benefit from survivin inhibition using YM155, for which TP53 mutational status can serve as a predictive biomarker. PMID:27159675

  5. Age-dependence of power spectral density and fractal dimension of bone mineralized matrix in atomic force microscope topography images: potential correlates of bone tissue age and bone fragility in female femoral neck trabeculae

    PubMed Central

    Milovanovic, Petar; Djuric, Marija; Rakocevic, Zlatko

    2012-01-01

    There is an increasing interest in bone nano-structure, the ultimate goal being to reveal the basis of age-related bone fragility. In this study, power spectral density (PSD) data and fractal dimensions of the mineralized bone matrix were extracted from atomic force microscope topography images of the femoral neck trabeculae. The aim was to evaluate age-dependent differences in the mineralized matrix of human bone and to consider whether these advanced nano-descriptors might be linked to decreased bone remodeling observed by some authors and age-related decline in bone mechanical competence. The investigated bone specimens belonged to a group of young adult women (n = 5, age: 20–40 years) and a group of elderly women (n = 5, age: 70–95 years) without bone diseases. PSD graphs showed the roughness density distribution in relation to spatial frequency. In all cases, there was a fairly linear decrease in magnitude of the power spectra with increasing spatial frequencies. The PSD slope was steeper in elderly individuals (−2.374 vs. −2.066), suggesting the dominance of larger surface morphological features. Fractal dimension of the mineralized bone matrix showed a significant negative trend with advanced age, declining from 2.467 in young individuals to 2.313 in the elderly (r = 0.65, P = 0.04). Higher fractal dimension in young women reflects domination of smaller mineral grains, which is compatible with the more freshly remodeled structure. In contrast, the surface patterns in elderly individuals were indicative of older tissue age. Lower roughness and reduced structural complexity (decreased fractal dimension) of the interfibrillar bone matrix in the elderly suggest a decline in bone toughness, which explains why aged bone is more brittle and prone to fractures. PMID:22946475

  6. [The application of osteoscintigraphy in forensic medical practice for the detection and differentiation of bone fractures in the living human].

    PubMed

    Gusarov, A A; Fetisov, V A; Kuprina, T A

    2016-01-01

    This paper is designed to present an example from the domestic expert practice with the successful application of the radionuclide technique to visualize the bone lesions in a victim of a traffic accident having concomitant pathology of the osseous-articular apparatus (Scheuermann-Mau disease). The use of the osteoscintigraphic method made it possible not only to confirm the injury to the spinal column and the sternum but also to ensure its differential diagnostics from the concurrent pathology. Also, the method allowed to detect the exact location of the fractures. Moreover, it proved possible to comprehensively characterize the mechanism underlying the bone fracture resulting from the car accident. PMID:27070038

  7. Enhancement of the Regenerative Potential of Anorganic Bovine Bone Graft Utilizing a Polyglutamate-Modified BMP2 Peptide with Improved Binding to Calcium-Containing Materials.

    PubMed

    Bain, Jennifer L; Bonvallet, Paul P; Abou-Arraj, Ramzi V; Schupbach, Peter; Reddy, Michael S; Bellis, Susan L

    2015-09-01

    Autogenous bone is the gold standard material for bone grafting in craniofacial and orthopedic regenerative medicine. However, due to complications associated with harvesting donor bone, clinicians often use commercial graft materials that may lose their osteoinductivity due to processing. This study was aimed to functionalize one of these materials, anorganic bovine bone (ABB), with osteoinductive peptides to enhance regenerative capacity. Two peptides known to induce osteoblastic differentiation of mesenchymal stem cells were evaluated: (1) DGEA, an amino acid motif within collagen I and (2) a biomimetic peptide derived from bone morphogenic protein 2 (BMP2pep). To achieve directed coupling of the peptides to the graft surface, the peptides were engineered with a heptaglutamate domain (E7), which confers specific binding to calcium moieties within bone mineral. Peptides with the E7 domain exhibited greater anchoring to ABB than unmodified peptides, and E7 peptides were retained on ABB for at least 8 weeks in vivo. To assess the osteoinductive potential of the peptide-conjugated ABB, ectopic bone formation was evaluated utilizing a rat subcutaneous pouch model. ABB conjugated with full-length recombinant BMP2 (rBMP2) was also implanted as a model for current clinical treatments utilizing rBMP2 passively adsorbed to carriers. These studies showed that E7BMP2pep/ABB samples induced more new bone formation than all other peptides, and an equivalent amount of new bone as compared with rBMP2/ABB. A mandibular defect model was also used to examine intrabony healing of peptide-conjugated ABB. Bone healing was monitored at varying time points by positron emission tomography imaging with (18)F-NaF, and it was found that the E7BMP2pep/ABB group had greater bone metabolic activity than all other groups, including rBMP2/ABB. Importantly, animals implanted with rBMP2/ABB exhibited complications, including inflammation and formation of cataract-like lesions in the eye, whereas

  8. Locust bean gum: Exploring its potential for biopharmaceutical applications

    PubMed Central

    Dionísio, Marita; Grenha, Ana

    2012-01-01

    Polysaccharides have been finding, in the last decades, very interesting and useful applications in the biomedical and, specifically, in the biopharmaceutical field. Locust bean gum is a polysaccharide belonging to the group of galactomannans, being extracted from the seeds of the carob tree (Ceratonia siliqua). This polymer displays a number of appealing characteristics for biopharmaceutical applications, among which its high gelling capacity should be highlighted. In this review, we describe critical aspects of locust bean gum, contributing for its role in biopharmaceutical applications. Physicochemical properties, as well as strong and effective synergies with other biomaterials are described. The potential for in vivo biodegradation is explored and the specific biopharmaceutical applications are discussed. PMID:22923958

  9. Histological evaluation of the influence of magnetic field application in autogenous bone grafts in rats

    PubMed Central

    Puricelli, Edela; Dutra, Nardier B; Ponzoni, Deise

    2009-01-01

    Background Bone grafts are widely used in oral and maxillofacial reconstruction. The influence of electromagnetic fields and magnets on the endogenous stimulation of target tissues has been investigated. This work aimed to assess the quality of bone healing in surgical cavities filled with autogenous bone grafts, under the influence of a permanent magnetic field produced by in vivo buried devices. Methods Metal devices consisting of commercially pure martensitic stainless steel washers and titanium screws were employed. Thirty male Wistar rats were divided into 3 experimental and 3 control groups. A surgical bone cavity was produced on the right femur, and a bone graft was collected and placed in each hole. Two metallic washers, magnetized in the experimental group but not in the control group, were attached on the borders of the cavity. Results The animals were sacrificed on postoperative days 15, 45 and 60. The histological analysis of control and experimental samples showed adequate integration of the bone grafts, with intense bone neoformation. On days 45 and 60, a continued influence of the magnetic field on the surgical cavity and on the bone graft was observed in samples from the experimental group. Conclusion The results showed intense bone neoformation in the experimental group as compared to control animals. The intense extra-cortical bone neoformation observed suggests that the osteoconductor condition of the graft may be more susceptible to stimulation, when submitted to a magnetic field. PMID:19134221

  10. Bioactive Glass Fiber Reinforced Starch-Polycaprolactone Composite for Bone Applications

    SciTech Connect

    Jukola, H.; Nikkola, L.; Tukiainen, M.; Kellomaeki, M.; Ashammakhi, N.; Gomes, M. E.; Reis, R. L.; Chiellini, F.; Chiellini, E.

    2008-02-15

    For bone regeneration and repair, combinations of different materials are often needed. Biodegradable polymers are often combined with osteoconductive materials, such as bioactive glass (BaG), which can also improve the mechanical properties of the composite. The aim of this study was to develop and characterize BaG fiber-reinforced starch-poly-{epsilon}-caprolactone (SPCL) composite. Sheets of SPCL (30/70 wt%) were produced using single-screw extrusion. They were then cut and compression molded in layers with BaG fibers to form composite structures of different combinations. Thermal, mechanical, and degradation properties of the composites were studied. The actual amount of BaG in the composites was determined using combustion tests. A strong endothermic peak indicating melting at about 56 deg. C was observed by differential scanning calorimetry (DSC) analysis. Thermal gravimetry analysis (TGA) showed that thermal decomposition of SPCL started at 325 deg. C with the decomposition of starch and continued at 400 deg. C with the degradation of polycaprolactone (PCL). Initial mechanical properties of the reinforced composites were at least 50% better than the properties of the non-reinforced composites. However, the mechanical properties of the composites after two weeks of hydrolysis were comparable to those of the non-reinforced samples. During the six weeks' hydrolysis the mass of the composites had decreased only by about 5%. The amount of glass in the composites remained the same for the six-week period of hydrolysis. In conclusion, it is possible to enhance the initial mechanical properties of SPCL by reinforcing it with BaG fibers. However, the mechanical properties of the composites are only sufficient for use as filler material and they need to be further improved to allow long-lasting bone applications.

  11. Bioactive Glass Fiber Reinforced Starch-Polycaprolactone Composite for Bone Applications

    NASA Astrophysics Data System (ADS)

    Jukola, H.; Nikkola, L.; Gomes, M. E.; Chiellini, F.; Tukiainen, M.; Kellomäki, M.; Chiellini, E.; Reis, R. L.; Ashammakhi, N.

    2008-02-01

    For bone regeneration and repair, combinations of different materials are often needed. Biodegradable polymers are often combined with osteoconductive materials, such as bioactive glass (BaG), which can also improve the mechanical properties of the composite. The aim of this study was to develop and characterize BaG fiber-reinforced starch-poly-ɛ-caprolactone (SPCL) composite. Sheets of SPCL (30/70 wt%) were produced using single-screw extrusion. They were then cut and compression molded in layers with BaG fibers to form composite structures of different combinations. Thermal, mechanical, and degradation properties of the composites were studied. The actual amount of BaG in the composites was determined using combustion tests. A strong endothermic peak indicating melting at about 56 °C was observed by differential scanning calorimetry (DSC) analysis. Thermal gravimetry analysis (TGA) showed that thermal decomposition of SPCL started at 325 °C with the decomposition of starch and continued at 400 °C with the degradation of polycaprolactone (PCL). Initial mechanical properties of the reinforced composites were at least 50% better than the properties of the non-reinforced composites. However, the mechanical properties of the composites after two weeks of hydrolysis were comparable to those of the non-reinforced samples. During the six weeks' hydrolysis the mass of the composites had decreased only by about 5%. The amount of glass in the composites remained the same for the six-week period of hydrolysis. In conclusion, it is possible to enhance the initial mechanical properties of SPCL by reinforcing it with BaG fibers. However, the mechanical properties of the composites are only sufficient for use as filler material and they need to be further improved to allow long-lasting bone applications.

  12. Radionuclide bone imaging and densitometry

    SciTech Connect

    Mettler, F.A.

    1988-01-01

    This book contains 13 selections. Some of the titles are: Radionuclides and the Normal Bone Scan; The Radionuclide Bone Scan in Malignant Disease; Pediatric Applications of Radionuclide Bone Imaging; The Radionuclide Bone Scan in Arthritis and Metabolic and Miscellaneous Disorders; and Soft Tissue Activity on the Radionuclide Bone Scan.

  13. Mobile Applications for Diabetes Self-Management: Status and Potential

    PubMed Central

    El-Gayar, Omar; Timsina, Prem; Nawar, Nevine; Eid, Wael

    2013-01-01

    Background Advancements in smartphone technology coupled with the proliferation of data connectivity has resulted in increased interest and unprecedented growth in mobile applications for diabetes self-management. The objective of this article is to determine, in a systematic review, whether diabetes applications have been helping patients with type 1 or type 2 diabetes self-manage their condition and to identify issues necessary for large-scale adoption of such interventions. Methods The review covers commercial applications available on the Apple App Store (as a representative of commercially available applications) and articles published in relevant databases covering a period from January 1995 to August 2012. The review included all applications supporting any diabetes self-management task where the patient is the primary actor. Results Available applications support self-management tasks such as physical exercise, insulin dosage or medication, blood glucose testing, and diet. Other support tasks considered include decision support, notification/alert, tagging of input data, and integration with social media. The review points to the potential for mobile applications to have a positive impact on diabetes self-management. Analysis indicates that application usage is associated with improved attitudes favorable to diabetes self-management. Limitations of the applications include lack of personalized feedback; usability issues, particularly the ease of data entry; and integration with patients and electronic health records. Conclusions Research into the adoption and use of user-centered and sociotechnical design principles is needed to improve usability, perceived usefulness, and, ultimately, adoption of the technology. Proliferation and efficacy of interventions involving mobile applications will benefit from a holistic approach that takes into account patients’ expectations and providers’ needs. PMID:23439183

  14. Potential National Security Applications of Nuclear Resonance Fluorescence Methods

    SciTech Connect

    Warren, Glen A.; Peplowski, Patrick N.; Caggiano, Joseph A.

    2009-06-09

    The objective of this report is to document the initial investigation into the possible research issues related to the development of NRF-based national security applications. The report discusses several potential applications ranging from measuring uranium enrichment in UF6 canisters to characterization of gas samples. While these applications are varied, there are only a few research issues that need to be addressed to understand the limitation of NRF in solving these problems. These research issues range from source and detector development to measuring small samples. The next effort is to determine how best to answer the research issues, followed by a prioritization of those questions to ensure that the most important are addressed. These issues will be addressed through either analytical calculations, computer simulations, analysis of previous data or collection of new measurements. It will also be beneficial to conduct a thorough examination of a couple of the more promising applications in order to develop concrete examples of how NRF may be applied in specific situations. The goals are to develop an understanding of whether the application of NRF is limited by technology or physics in addressing national security applications, to gain a motivation to explore those possible applications, and to develop a research roadmap so that those possibilities may be made reality.

  15. Bone Grafts

    MedlinePlus

    A bone graft transplants bone tissue. Surgeons use bone grafts to repair and rebuild diseased bones in your hips, knees, spine, and sometimes other bones and joints. Grafts can also repair bone loss caused by some ...

  16. Bone tumor

    MedlinePlus

    Tumor - bone; Bone cancer; Primary bone tumor; Secondary bone tumor ... The cause of bone tumors is unknown. They often occur in areas of the bone that grow rapidly. Possible causes include: Genetic defects ...

  17. Effect of hyaluronic acid in bone formation and its applications in dentistry.

    PubMed

    Zhao, Ningbo; Wang, Xin; Qin, Lei; Zhai, Min; Yuan, Jing; Chen, Ji; Li, Dehua

    2016-06-01

    Hyaluronic acid (HA), the simplest glycosaminoglycan, participates in several important biological procedures, including mediation of cellular signaling, regulation of cell adhesion and proliferation, and manipulation of cell differentiation. The effect of HA on cell proliferation and differentiation depends on its molecular weight (MW) and concentration. Moreover, the properties of high viscosity, elasticity, highly negative charge, biocompatibility, biodegradability, and nonimmunogenicity make HA attractive in tissue engineering and disease treatment. This review comprises an overview of the effect of HA on cell proliferation and differentiation in vitro, the role of HA in bone regeneration in vivo, and the clinical applications of HA in dentistry, focusing on the mechanism underlining the effect of MW and concentration of HA on cell proliferation and osteogenic differentiation. It is expected that practical progress of HA both in laboratory-based experiments and clinical applications will be achieved in the next few years. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1560-1569, 2016. PMID:27007721

  18. Bone ingrowth potential of electron beam and selective laser melting produced trabecular-like implant surfaces with and without a biomimetic coating.

    PubMed

    Biemond, J E; Hannink, G; Verdonschot, N; Buma, P

    2013-03-01

    The bone ingrowth potential of trabecular-like implant surfaces produced by either selective laser melting (SLM) or electron beam melting (EBM), with or without a biomimetic calciumphosphate coating, was examined in goats. For histological analysis and histomorphometry of bone ingrowth depth and bone implant contact specimens were implanted in the femoral condyle of goats. For mechanical push out tests to analyse mechanical implant fixation specimens were implanted in the iliac crest. The follow up periods were 4 (7 goats) and 15 weeks (7 goats). Both the SLM and EBM produced trabecular-like structures showed a variable bone ingrowth after 4 weeks. After 15 weeks good bone ingrowth was found in both implant types. Irrespective to the follow up period, and the presence of a coating, no histological differences in tissue reaction around SLM and EBM produced specimens was found. Histological no coating was detected at 4 and 15 weeks follow up. At both follow up periods the mechanical push out strength at the bone implant interface was significantly lower for the coated SLM specimens compared to the uncoated SLM specimens. The expected better ingrowth characteristics and mechanical fixation strength induced by the coating were not found. The lower mechanical strength of the coated specimens produced by SLM is a remarkable result, which might be influenced by the gross morphology of the specimens or the coating characteristics, indicating that further research is necessary. PMID:23254345

  19. Serum Heme Oxygenase-1 and BMP-7 Are Potential Biomarkers for Bone Metabolism in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis

    PubMed Central

    Yuan, Tong-ling; Chen, Jin; Tong, Yan-li; Zhang, Yan; Liu, Yuan-yuan; Wei, James Cheng-Chung; Liu, Yi; Herrmann, Martin

    2016-01-01

    Backgrounds. Heme oxygenase-1 (HO-1) has been reported to play a regulatory role in osteoclastogenesis. Bone morphogenetic protein (BMP) pathways induce osteoblastic differentiation and bone remodeling. Aims. To identify serum levels of HO-1, BMP-7, and Runt related-transcription factor 2 (Runx2) in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) and to investigate the relationships between HO-1, BMP-7, Runx2, and other common biomarkers for bone metabolism. Results. Serum levels of HO-1 and BMP-7 were revealed to be significantly higher in patients with RA or AS than in healthy controls (p < 0.01). In RA group, HO-1 was positively correlated with BMP-7, Runx2, and tartrate-resistant acid phosphatase-5b (TRAP-5b) (p < 0.05, resp.), BMP-7 was positively correlated with Runx2 and TRAP-5b (p < 0.05, resp.), and Runx2 was negatively correlated with N-terminal midfragment of osteocalcin (NMID) (p < 0.05). In AS group, we observed identical correlation between HO-1 and BMP-7, but opposite correlations between BMP-7 and TRAP-5b and between Runx2 and NMID, when comparing with the RA cohort. Conclusion. Our findings suggest that HO-1 and BMP-7 are potential biomarkers for bone metabolism in patients with RA and AS. The different correlations between the bone markers point to distinct differences in bone remodeling pathways in the two types of arthritis. PMID:27314037

  20. In vitro bioactivity assessment of composite membrane containing antimicrobial lauric acid for guided bone regeneration in dental application

    NASA Astrophysics Data System (ADS)

    Suleiman, Muhammad Jabir; Kalitheertha, Jamuna Thevi; Sabri, Siti Noorzidah

    2015-07-01

    The manuscript reflect research work in fabrication of a triple layered composite membrane and to perform an in vitro bioactivity evaluation on composite membrane containing antimicrobial lauric acid. Poly(lactic-co-glycolic acid) (PLGA) matrix was incorporated with various amounts of nanoapatite (NAp) and lauric acid (LA) to form a triple-layered composite membrane. This membrane was prepared using a single step fabrication technique comprising of solvent casting, thermally induced phase separation and solvent leaching processes. Apatite mineralization was detected on the composite membranes within 30 days of exposure to simulated body fluid (SBF) and showed increased apatite formation at 30-60wt% of NAp content in the PLGA matrix on layer 3 (L3), that has the highest amount of NAp compared with layer 1 (L1) and layer 2 (L2) of the membrane. However, apatite mineralization was not detected on pure PLGA membrane. In addition, incorporation of LA on L1 and L2 has no influence on apatite mineral formation as none detected on these surfaces. The presence of NAp determines the formation of apatite crystals on the composite membrane. These membranes with triple layered design and bioactive properties showed potential use for guided bone regeneration purposes in dental application.

  1. Thermophilic and alkaliphilic Actinobacteria: biology and potential applications

    PubMed Central

    Shivlata, L.; Satyanarayana, Tulasi

    2015-01-01

    Microbes belonging to the phylum Actinobacteria are prolific sources of antibiotics, clinically useful bioactive compounds and industrially important enzymes. The focus of the current review is on the diversity and potential applications of thermophilic and alkaliphilic actinobacteria, which are highly diverse in their taxonomy and morphology with a variety of adaptations for surviving and thriving in hostile environments. The specific metabolic pathways in these actinobacteria are activated for elaborating pharmaceutically, agriculturally, and biotechnologically relevant biomolecules/bioactive compounds, which find multifarious applications. PMID:26441937

  2. The applicability of the Greulich & Pyle Atlas for bone age assessment in primary school-going children of Karachi, Pakistan

    PubMed Central

    Manzoor Mughal, Arsalan; Hassan, Nuzhat; Ahmed, Anwar

    2014-01-01

    Objective: To assess the degree of applicability of bone age calculated by Greulich & Pyle Atlas in estimation of chronological age for therapeutic and medico legal purposes. Methods: Two Hundred and Twenty children (139 males, 81 females) between ages of 56 and 113 months (4.5 to 9.5 years) were randomly selected from 4 primary schools of Shireen Jinnah & Clifton, Karachi. Digital images of hand and wrist radiographs were obtained by a computed radiography at Ziauddin Hospital Clifton. Bone ages were computed using Greulich & Pyle Atlas by radiologists at Ziauddin Hospital, North Nazimabad, Karachi. Results: On average, the Greulich & Pyle Atlas underestimates chronological age by 6.65 ± 13.47 months in females and 15.78 ± 12.83 months in males (p-values < 0.001). High correlation was found between chronological age and bone age in both genders (Females r=0.778; p-value< 0.001, Males r=0.816; p-value < 0.001). Conclusion: Bone age calculated by Greulich & Pyle Atlas should not be used for estimating chronological age in children of ages 56-113 months in situations where high accuracy is required (e.g. medicolegal cases). However, serial measurements of bone age by this atlas can be used in management of growth related endocrine disorders in these children. PMID:24772153

  3. Quality of diet and potential renal acid load as risk factors for reduced bone density in elderly women

    PubMed Central

    Pedone, Claudio; Napoli, Nicola; Lauretani, Fulvio; Pozzilli, Paolo; Ferrucci, Luigi; Antonelli-Incalzi, Raffaele

    2010-01-01

    Background Bone mass density (BMD) may be influenced by the general dietary pattern and the potential renal acid load (PRAL). Objective To evaluate the association between PRAL and BMD. Methods We evaluated BMD using computed tomography and dietary intake using the EPIC questionnaire in 543 community-living women aged 60 years and older. We grouped the participants according to tertiles of total, trabecular and cortical BMD, and compared demographic, anthropometric and nutritional characteristics across groups. Analyses were repeated using tertiles of BMD variation over a 6-years follow-up. Results Total BMD was inversely associated with age, time since menopause, and creatinine clearance. The intake of PUFAs was slightly higher among women with the highest total BMD, none of the other nutrients taken into account nor PRAL was associated with total BMD. Similar results were found for trabecular BMD, with the exception that alcohol intake was associated with lower bone density. Cortical BMD was associated with vitamin D intake (1.6, 1.8, and 1.8 mcg/day in first, second and third tertile, respectively) and serum 25-OH vitamin D (38.8, 43.2, and 49.5 nmol/L in the first, second, and third tertile, respectively). In the longitudinal analysis, a lower BMI was associated with greater loss of total BMD, while lower serum 25-hydroxy vitamin D at baseline was associated with smaller loss of cortical BMD. Conclusions We found no relationship between dietary acid load and BMD. We also confirmed the role of well recognized risk factor for osteoporosis and found a possible protective effect of PUFA intake on BMD. PMID:20005315

  4. Bone Progenitors Produced by Direct Osteogenic Differentiation of the Unprocessed Bone Marrow Demonstrate High Osteogenic Potential In Vitro and In Vivo

    PubMed Central

    Weinreb, Miron; Abramov, Natalie; Shinar, Doron; Merchav, Shoshana; Schwartz, Aharon; Shirvan, Mitchell

    2012-01-01

    Abstract Tissue-engineered bone grafts seeded with mesenchymal stem cells (MSCs) have been sought as a replacement for bone grafts currently used for bone repair. For production of osteogenic constructs, MSCs are isolated from bone marrow (BM) or other tissues, expanded in culture, then trypsinized, and seeded on a scaffold. Predifferentiation of seeded cells is often desired. We describe here bone progenitor cells (BPCs) obtained by direct osteogenic differentiation of unprocessed BM bypassing isolation of MSCs. Human BM aspirates were incubated for 2 weeks with a commonly used osteogenic medium (OM), except no fetal calf serum, serum substitutes, or growth factors were added, because responding stem and/or progenitor cells were present in the BM milieu. The adherent cells remaining after the culture medium and residual BM were washed out, expressed high levels of bone-specific alkaline phosphatase (ALP) on their surface, demonstrated high ALP activity, were capable of mineralization of the intercellular space, and expressed genes associated with osteogenesis. These parameters in BPCs were similar and even at higher levels compared to MSCs subjected to osteogenic differentiation for 2 weeks. The yield of BPCs per 1 mL BM was 0.71±0.39×106. In comparison, the yield of MSCs produced by adhesion of mononuclear cells derived from the same amount of BM and cultured in a commercial growth medium for 2 weeks was 0.3±0.17×106. When a scaffold was added to the BM-OM mixture, and the mixture was cultured in a simple rotational bioreactor; the resulting BPCs were obtained already seeded on the scaffold. BPCs seeded on scaffolds were capable of proliferation for at least 6 weeks, keeping high levels of ALP activity, expressing osteogenic genes, and mineralizing the scaffolds. Autologous rat BPCs seeded on various scaffolds were transplanted into critical-size calvarial defects. Six weeks after transplantation of polylactic acid/polyglycolic acid scaffolds, 76.1%±18

  5. Neurotrophic Factors and Their Potential Applications in Tissue Regeneration

    PubMed Central

    Le, Quynh-Thu

    2016-01-01

    Neurotrophic factors are growth factors that can nourish neurons and promote neuron survival and regeneration. They have been studied as potential drug candidates for treating neurodegenerative diseases. Since their identification, there are more and more evidences to indicate that neurotrophic factors are also expressed in non-neuronal tissues and regulate the survival, anti-inflammation, proliferation and differentiation in these tissues. This mini review summarizes the characteristics of the neurotrophic factors and their potential clinical applications in the regeneration of neuronal and non-neuronal tissues. PMID:26611762

  6. The Natural Flavonoid Pinocembrin: Molecular Targets and Potential Therapeutic Applications.

    PubMed

    Lan, Xi; Wang, Wenzhu; Li, Qiang; Wang, Jian

    2016-04-01

    Pinocembrin is a natural flavonoid compound extracted from honey, propolis, ginger roots, wild marjoram, and other plants. In preclinical studies, it has shown anti-inflammatory and neuroprotective effects as well as the ability to reduce reactive oxygen species, protect the blood-brain barrier, modulate mitochondrial function, and regulate apoptosis. Considering these pharmaceutical characteristics, pinocembrin has potential as a drug to treat ischemic stroke and other clinical conditions. In this review, we summarize its pharmacologic characteristics and discuss its mechanisms of action and potential therapeutic applications. PMID:25744566

  7. Application of buccal fat pad-derived stem cells in combination with autogenous iliac bone graft in the treatment of maxillomandibular atrophy: a preliminary human study.

    PubMed

    Khojasteh, A; Sadeghi, N

    2016-07-01

    Stem cell therapy for the treatment of bone defects is an alternative or adjunct to autologous bone grafting. This study assessed the efficacy of buccal fat pad-derived stem cells (BFPSCs) with iliac bone block grafting for the treatment of extensive human alveolar ridge defects. Eight patients with extensive jaw atrophy were selected for this study. The jaws were reconstructed with non-vascularized anterior iliac crest bone blocks. Gaps between the blocks were filled with freeze-dried bone granules and covered with a collagen membrane. In the test group (n=4), these granules were seeded with BFPSCs. Cone beam computed tomography scans were used to assess the amount of new bone formed at six sites in each patient. Trephine biopsies of 2-mm were also taken from the graft site during implant placement for histomorphometric analysis. The mean bone width change at the graft site was greater in the test group than in the control group (3.94±1.62mm vs. 3.01±0.89mm). New bone formation was 65.32% in the test group versus 49.21% in the control group. The application of BFPSCs in conjunction with iliac bone block grafts may increase the amount of new bone formation and decrease secondary bone resorption in extensively atrophic jaws. PMID:26846793

  8. Potential applications of immunoassays in studies of flatfish recruitment

    NASA Astrophysics Data System (ADS)

    Feller, Robert J.

    The fisheries recruitment-stock problem, a lack of correlation between measures of reproductive output of the parent stock and recruitment to the fishery, has several potential biotic and abiotic causes. Immunoassays may be useful in examining several aspects of this and several other problems in flatfish ecology: stock identification, parasitism and disease, and trophic interactions. Given stage-specific antisera capable of recognozing antigenic moieties of, for instance, eggs, larvae, or newly-settled juveniles, it is possible to screen stomach contents of many putative predators ( e.g., shrimp or crabs) rapidly for the presence and amounts of platfish prey. This trophic application of immunological methods has great promise for measuring loss of potential recruits to predation. All immunoassays are limited by the quality of antisera used and the researcher's ability to interpret quantitative data in an ecologically meaningful way. Key references for applications of immunoassays in fish-related questions are provided with recommendations for their utilization.

  9. Dexamethasone Regulates EphA5, a Potential Inhibitory Factor with Osteogenic Capability of Human Bone Marrow Stromal Cells.

    PubMed

    Yamada, Tsuyoshi; Yoshii, Toshitaka; Yasuda, Hiroaki; Okawa, Atsushi; Sotome, Shinichi

    2016-01-01

    We previously demonstrated the importance of quality management procedures for the handling of human bone marrow stromal cells (hBMSCs) and provided evidence for the existence of osteogenic inhibitor molecules in BMSCs. One candidate inhibitor is the ephrin type-A receptor 5 (EphA5), which is expressed in hBMSCs and upregulated during long-term culture. In this study, forced expression of EphA5 diminished the expression of osteoblast phenotypic markers. Downregulation of endogenous EphA5 by dexamethasone treatment promoted osteoblast marker expression. EphA5 could be involved in the normal growth regulation of BMSCs and could be a potential marker for replicative senescence. Although Eph forward signaling stimulated by ephrin-B-Fc promoted the expression of ALP mRNA in BMSCs, exogenous addition of EphA5-Fc did not affect the ALP level. The mechanism underlying the silencing of EphA5 in early cultures remains unclear. EphA5 promoter was barely methylated in hBMSCs while histone deacetylation could partially suppress EphA5 expression in early-passage cultures. In repeatedly passaged cultures, the upregulation of EphA5 independent of methylation could competitively inhibit osteogenic signal transduction pathways such as EphB forward signaling. Elucidation of the potential inhibitory function of EphA5 in hBMSCs may provide an alternative approach for lineage differentiation in cell therapy strategies and regenerative medicine. PMID:27057165

  10. Transient Receptor Potential Melastatin Type 7 Channel Is Critical for the Survival of Bone Marrow Derived Mesenchymal Stem Cells

    PubMed Central

    Feng, Ji-Ming; Figueiredo, Marxa L.; Zhang, Hanjie; Nelson, Piper L.; Marigo, Vanessa; Beck, Andreas

    2010-01-01

    The transient receptor potential melastatin type 7 channel (TRPM7) is a member of the TRP family of ion channels that is essential for cell proliferation and viability. Mesenchymal stem cells (MSCs) from bone marrow are a potential source for tissue repair due to their ability to differentiate into specialized cells. However, the role of TRPM7 in stem cells is unknown. In this study, we characterized TRPM7 in mouse MSCs using molecular biology, immunocytochemistry, and patch clamp. We also investigated TRPM7 function using a lentiviral vector and specific shRNA to knockdown gene expression. By RT-PCR and immunocytochemistry, we identified TRPM7, but not TRPM6, a close family member with similar function. Electrophysiological recordings during depletion of intracellular Mg2+ or Mg2+-ATP resulted in the development of currents typical for the channel. Furthermore, 2-aminoethoxydiphenyl borate (1 pM–100 μM) inhibited TRPM7 in a concentration-dependent manner. The molecular suppression of TRPM7 significantly decreased MSC proliferation and viability as determined by MTT assay. In addition, TRPM7 gene expression was up-regulated during osteogenesis. These findings demonstrate that TRPM7 is required for MSC survival and perhaps involved in the differentiation process. PMID:19929312

  11. Dexamethasone Regulates EphA5, a Potential Inhibitory Factor with Osteogenic Capability of Human Bone Marrow Stromal Cells

    PubMed Central

    Yamada, Tsuyoshi; Yoshii, Toshitaka; Yasuda, Hiroaki; Okawa, Atsushi; Sotome, Shinichi

    2016-01-01

    We previously demonstrated the importance of quality management procedures for the handling of human bone marrow stromal cells (hBMSCs) and provided evidence for the existence of osteogenic inhibitor molecules in BMSCs. One candidate inhibitor is the ephrin type-A receptor 5 (EphA5), which is expressed in hBMSCs and upregulated during long-term culture. In this study, forced expression of EphA5 diminished the expression of osteoblast phenotypic markers. Downregulation of endogenous EphA5 by dexamethasone treatment promoted osteoblast marker expression. EphA5 could be involved in the normal growth regulation of BMSCs and could be a potential marker for replicative senescence. Although Eph forward signaling stimulated by ephrin-B-Fc promoted the expression of ALP mRNA in BMSCs, exogenous addition of EphA5-Fc did not affect the ALP level. The mechanism underlying the silencing of EphA5 in early cultures remains unclear. EphA5 promoter was barely methylated in hBMSCs while histone deacetylation could partially suppress EphA5 expression in early-passage cultures. In repeatedly passaged cultures, the upregulation of EphA5 independent of methylation could competitively inhibit osteogenic signal transduction pathways such as EphB forward signaling. Elucidation of the potential inhibitory function of EphA5 in hBMSCs may provide an alternative approach for lineage differentiation in cell therapy strategies and regenerative medicine. PMID:27057165

  12. Potential applications of nanostructured materials in nuclear waste management.

    SciTech Connect

    Braterman, Paul S. (The University of North Texas, Denton, TX); Phol, Phillip Isabio; Xu, Zhi-Ping (The University of North Texas, Denton, TX); Brinker, C. Jeffrey; Yang, Yi; Bryan, Charles R.; Yu, Kui; Xu, Huifang (University of New Mexico, Albuquerque, NM); Wang, Yifeng; Gao, Huizhen

    2003-09-01

    This report summarizes the results obtained from a Laboratory Directed Research & Development (LDRD) project entitled 'Investigation of Potential Applications of Self-Assembled Nanostructured Materials in Nuclear Waste Management'. The objectives of this project are to (1) provide a mechanistic understanding of the control of nanometer-scale structures on the ion sorption capability of materials and (2) develop appropriate engineering approaches to improving material properties based on such an understanding.

  13. Perfect absorbers on curved surfaces and their potential applications.

    PubMed

    Alaee, Rasoul; Menzel, Christoph; Rockstuhl, Carsten; Lederer, Falk

    2012-07-30

    Recently perfect metamaterial absorbers triggered some fascination since they permit the observation of an extreme interaction of light with a nanostructured thin film. For the first time we evaluate here the functionality of such perfect absorbers if they are applied on curved surfaces. We probe their optical response and discuss potential novel applications. Examples are the complete suppression of back-scattered light from the covered objects, rendering it cloaked in reflection, and their action as optical black holes. PMID:23038388

  14. Potential impacts of nanotechnology on energy transmission applications and needs.

    SciTech Connect

    Elcock, D.; Environmental Science Division

    2007-11-30

    The application of nanotechnologies to energy transmission has the potential to significantly impact both the deployed transmission technologies and the need for additional development. This could be a factor in assessing environmental impacts of right-of-way (ROW) development and use. For example, some nanotechnology applications may produce materials (e.g., cables) that are much stronger per unit volume than existing materials, enabling reduced footprints for construction and maintenance of electricity transmission lines. Other applications, such as more efficient lighting, lighter-weight materials for vehicle construction, and smaller batteries having greater storage capacities may reduce the need for long-distance transport of energy, and possibly reduce the need for extensive future ROW development and many attendant environmental impacts. This report introduces the field of nanotechnology, describes some of the ways in which processes and products developed with or incorporating nanomaterials differ from traditional processes and products, and identifies some examples of how nanotechnology may be used to reduce potential ROW impacts. Potential environmental, safety, and health impacts are also discussed.

  15. Design and fabrication of a flexible large area fabric transducer for bone healing application

    NASA Astrophysics Data System (ADS)

    Jadidian, Bahram

    The electromechanical transducers have found applications in their either passive or active modes. These applications include hydrophone, medical imaging, nondestructive evaluation, motors, sensors, actuators, civil and aerospace engineering. Other medical applications for ultrasonic transducers include therapeutics, osteosynthesis, lithotripsy, thrombolysis, and transdermal drug administration. During the past few decades, lead zirconate titanate (PZT), has been utilized in transducer applications in the form of a bulk piezoelectric ceramic and/or ceramic-polymer composites because of its high piezoelectric charge coefficient d33. The usage of piezoelectric ceramic/polymer composites allows designers to overcome some of the problems dealing with either monolithic piezoceramics or piezopolymers in transducer applications. In this work, a variety of composites with different connectivity patterns were formed. Composites with 1-3 connectivity were fabricated using bundling and collimating methods. Sized and unsized fibers were woven to form fabric. The fabric was used to form 3-3 composites and spiral structures. Square sheets of the fabric were laminated on top of each other, heat treated, and embedded in different types of polymer. The effect of applied pressure on the stack during heat treatment was studied. Plane fabric was formed in the spiral manner and used to construct piezocomposites. A piezoelectric transducer with high thickness coupling coefficient and its matching layer were exploited for bone healing application. One of the structures with the highest electromechanical properties, developed in this work, was chosen for the array fabrication. The spiral composite elements, with the best properties, were arranged in a 3 x 4 format embedded in a flexible polymer. The mechanical endurance of the elements and the array was studied. A large area flexible matching layer with low attenuation was developed. An extensive study was performed to determine the

  16. Potential applications of bioprocess technology in petroleum industry.

    PubMed

    Singh, Ajay; Singh, Brajesh; Ward, Owen

    2012-11-01

    Petroleum refining is traditionally based on the use of physicochemical processes such as distillation and chemical catalysis that operate under high temperatures and pressures conditions, which are energy intensive and costly. Biotechnology has become an important tool for providing new approaches in petroleum industry during oil production, refining and processing as well as managing environmentally safe pollutant remediation and disposal practices. Earlier biotechnology applications in the petroleum industry were limited to microbial enhanced oil recovery, applications of bioremediation to contaminated marine shorelines, soils and sludges. The potential role of bioprocess technology in this industry has now expanded further into the areas of biorefining and upgrading of fuels, production of fine chemicals, control of souring during production and air VOC biofiltration. In this paper we provide an overview of the major applications of bioprocesses and technology development in the petroleum industry both in upstream and downstream areas and highlight future challenges and opportunities. PMID:22829348

  17. Solar energy in California industry - Applications, characteristics and potential

    NASA Technical Reports Server (NTRS)

    Barbieri, R. H.; Pivirotto, D. S.

    1978-01-01

    Results of a survey to determine the potential applicability of solar thermal energy to industrial processes in California are presented. It is found that if the heat for all industrial processes at temperatures below 212 F were supplied by solar energy, total state energy consumption could be reduced by 100 trillion Btus (2%), while the use of solar energy in processes between 212 and 350 F could displace 500 trillion Btus. The issues and problems with which solar energy must contend are illustrated by a description of fluid milk processing operations. Solar energy application is found to be technically feasible for processes with thermal energy requirements below 212 F, with design, and degree of technical, economic and management feasibility being site specific. It is recommended that the state provide support for federal and industrial research, development and demonstration programs in order to stimulate acceptance of solar process heat application by industry.

  18. Potential applications of keratinocytes derived from human embryonic stem cells.

    PubMed

    Movahednia, Mohammad M; Kidwai, Fahad K; Jokhun, Doorgesh S; Squier, Christopher A; Toh, Wei Seong; Cao, Tong

    2016-01-01

    Although skin grafting is one of the most advanced cell therapy technique, wide application of skin substitutes is hampered by the difficulty in securing sufficient amount of epidermal substitute. Additionally, in understanding the progression of skin aging and disease, and in screening the cosmetic and pharmaceutical products, there is lack of a satisfactory human skin-specific in vitro model. Recently, human embryonic stem cells (hESCs) have been proposed as an unlimited and reliable cell source to obtain almost all cell types present in the human body. This review focuses on the potential off-the-shelf use of hESC-derived keratinocytes for future clinical applications as well as a powerful in vitro skin model to study skin function and integrity, host-pathogen interactions and disease pathogenesis. Furthermore, we discuss the industrial applications of hESC-derived keratinized multi-layer epithelium which provides a human-like test platform for understanding disease pathogenesis, evaluation of new therapeutic modalities and assessment of the safety and efficacy of skin cosmetics and therapeutics. Overall, we conclude that the hESC-derived keratinocytes have great potential for clinical, research and industrial applications. PMID:26663861

  19. Bone Tissue Engineering: Recent Advances and Challenges

    PubMed Central

    Amini, Ami R.; Laurencin, Cato T.; Nukavarapu, Syam P.

    2013-01-01

    The worldwide incidence of bone disorders and conditions has trended steeply upward and is expected to double by 2020, especially in populations where aging is coupled with increased obesity and poor physical activity. Engineered bone tissue has been viewed as a potential alternative to the conventional use of bone grafts, due to their limitless supply and no disease transmission. However, bone tissue engineering practices have not proceeded to clinical practice due to several limitations or challenges. Bone tissue engineering aims to induce new functional bone regeneration via the synergistic combination of biomaterials, cells, and factor therapy. In this review, we discuss the fundamentals of bone tissue engineering, highlighting the current state of this field. Further, we review the recent advances of biomaterial and cell-based research, as well as approaches used to enhance bone regeneration. Specifically, we discuss widely investigated biomaterial scaffolds, micro- and nano-structural properties of these scaffolds, and the incorporation of biomimetic properties and/or growth factors. In addition, we examine various cellular approaches, including the use of mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), adult stem cells, induced pluripotent stem cells (iPSCs), and platelet-rich plasma (PRP), and their clinical application strengths and limitations. We conclude by overviewing the challenges that face the bone tissue engineering field, such as the lack of sufficient vascularization at the defect site, and the research aimed at functional bone tissue engineering. These challenges will drive future research in the field. PMID:23339648

  20. Symmetry preserving optimised effective potential theory (application to atoms)

    NASA Astrophysics Data System (ADS)

    Theophilou, Andreas K.; Papaconstantinou, Petros G.; Glushkov, Vitaly

    2006-02-01

    In this paper, general symmetry properties of physical systems are used in order to produce a mapping of the external potential of a many electron system to its optimized effective potential (OEP). The so derived effective potential is used to calculate the OEP ground state energies and spin orbitals. Applications are made to atoms and ions and the results are compared to those of the exact Hartree-Fock approximation. The relative deviations from the exact HF theory (triangleE/E) are of the order of 10-4. The same holds for molecules. One of the features of the present theory is that the many electron wave functions derived by the present method, transform according to the irreducible representations of the exact states.

  1. Tailoring of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymers for bone tissue applications

    NASA Astrophysics Data System (ADS)

    Liu, Hui

    Considerable scientific and technological progress has been made in formulating biomaterials based on natural and synthetic polymers for ultimate use in bone tissue scaffolding. One class of polymers that has drawn attention in recent years for bone tissue engineering application is the biodegradable polymer poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). PHBV, a microbial polymer, has gained special importance because of favorable mechanical characteristics, biological properties, highly adaptable structure, non-toxic degradation products, and minimal inflammatory response when used as scaffold. However, the lack of natural cell recognition sites on PHBV has resulted in delayed cell attachment, proliferation, differentiation, and tissue regeneration on the polymer. The primary objective of this research is to modify PHBV so as to improve the biocompatibility of the matrix. An approach was developed to prepare porous and bioactive molecule coated scaffold so as to improve the biocompatibility of PHBV matrix. We investigated the role of porosity, collagen coating, and ozone treatment of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) scaffold on cell proliferation. Based on biochemical assay, we established that maximum cell proliferation occurs on collagen coated and ozone treated porous PHBV film followed by collagen coated porous PHBV film than on porous PHBV film and the least on nonporous PHBV film. Confocal microscopy in combination with biochemical assay was used to generate 3D map of viable cell proliferation on the bulk PHBV matrix. The cells were cultivated on modified PHBV film in mineralization media containing beta-glycerol phosphate for predetermined time interval and later calcium deposits were stained with alizarin red-S assay. Atomic absorption (AA) technique was used to measure the Ca2+ content of the medium and it was found that the longer the cells were incubated in organic phosphate medium, the greater amount of Ca2+ from the medium

  2. Potential role of 20S proteasome in maintaining stem cell integrity of human bone marrow stromal cells in prolonged culture expansion

    SciTech Connect

    Lu, Li; Song, Hui-Fang; Zhang, Wei-Guo; Liu, Xue-Qin; Zhu, Qian; Cheng, Xiao-Long; Yang, Gui-Jiao; Li, Ang; Xiao, Zhi-Cheng

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Prolonged culture expansion retards proliferation and induces senescence of hBMSCs. Black-Right-Pointing-Pointer Reduced 20S proteasomal activity and expression potentially contribute to cell aging. Black-Right-Pointing-Pointer MG132-mediated 20S proteasomal inhibition induces senescence-like phenotype. Black-Right-Pointing-Pointer 18{alpha}-GA stimulates proteasomal activity and restores replicative senescence. Black-Right-Pointing-Pointer 18{alpha}-GA retains differentiation without affecting stem cell characterizations. -- Abstract: Human bone marrow stromal cells (hBMSCs) could be used in clinics as precursors of multiple cell lineages following proper induction. Such application is impeded by their characteristically short lifespan, together with the increasing loss of proliferation capability and progressive reduction of differentiation potential after the prolonged culture expansion. In the current study, we addressed the possible role of 20S proteasomes in this process. Consistent with prior reports, long-term in vitro expansion of hBMSCs decreased cell proliferation and increased replicative senescence, accompanied by reduced activity and expression of the catalytic subunits PSMB5 and PSMB1, and the 20S proteasome overall. Application of the proteasome inhibitor MG132 produced a senescence-like phenotype in early passages, whereas treating late-passage cells with 18{alpha}-glycyrrhetinic acid (18{alpha}-GA), an agonist of 20S proteasomes, delayed the senescence progress, enhancing the proliferation and recovering the capability of differentiation. The data demonstrate that activation of 20S proteasomes assists in counteracting replicative senescence of hBMSCs expanded in vitro.

  3. Staining procedure for the detection of microcracks: application to ewe bone.

    PubMed

    Portero-Muzy, N R; Chavassieux, P M; Arlot, M E; Chapurlat, R D

    2011-10-01

    Microcracks are one of the determinants of the bone strength and their accumulation may contribute to increased fracture risk. They are detected after bulk staining with various dyes, including basic fuschin, calcein and xylenol orange. The duration of staining usually varies across types of bone and species. The ewe is a large animal with a bone remodeling similar to humans, used as an animal model in bone histomorphometry studies. The aim of the present study was to determine the optimal conditions for bulk staining with xylenol orange of ewe bone. Xylenol orange 5mM in 70% ethanol was applied to iliac crest and vertebral biopsies for 2 or 15 days or 1, 2 or 3 months. After embedding, sections of 40, 50 and 80 μm thick were cut with either a precision diamond wire saw or a microtome. The staining was not visible after 2 or 15 days and was heterogeneous after 1 or 2 months. The quality of 40 and 50 μm thick sections was not preserved compared with those of 80 μm. Microcracks were suitably observed on ewe bone after bulk staining with xylenol orange for 3 months, in 80 μm thick sections. We conclude that the staining procedures should differ when examining ewe or human bone. This may be due to differences in bone matrix composition. PMID:21782048

  4. Cardiogel: A Nano-Matrix Scaffold with Potential Application in Cardiac Regeneration Using Mesenchymal Stem Cells

    PubMed Central

    Santhakumar, Rajalakshmi; Vidyasekar, Prasanna; Verma, Rama Shanker

    2014-01-01

    3-Dimensional conditions for the culture of Bone Marrow-derived Stromal/Stem Cells (BMSCs) can be generated with scaffolds of biological origin. Cardiogel, a cardiac fibroblast-derived Extracellular Matrix (ECM) has been previously shown to promote cardiomyogenic differentiation of BMSCs and provide protection against oxidative stress. To determine the matrix composition and identify significant proteins in cardiogel, we investigated the differences in the composition of this nanomatrix and a BMSC-derived ECM scaffold, termed as ‘mesogel’. An optimized protocol was developed that resulted in efficient decellularization while providing the maximum yield of ECM. The proteins were sequentially solubilized using acetic acid, Sodium Dodecyl Sulfate (SDS) and Dithiothreitol (DTT). These proteins were then analyzed using surfactant-assisted in-solution digestion followed by nano-liquid chromatography and tandem mass spectrometry (nLC-MS/MS). The results of these analyses revealed significant differences in their respective compositions and 17 significant ECM/matricellular proteins were differentially identified between cardiogel and mesogel. We observed that cardiogel also promoted cell proliferation, adhesion and migration while enhancing cardiomyogenic differentiation and angiogenesis. In conclusion, we developed a reproducible method for efficient extraction and solubilization of in vitro cultured cell-derived extracellular matrix. We report several important proteins differentially identified between cardiogel and mesogel, which can explain the biological properties of cardiogel. We also demonstrated the cardiomyogenic differentiation and angiogenic potential of cardiogel even in the absence of any external growth factors. The transplantation of Bone Marrow derived Stromal/Stem Cells (BMSCs) cultured on such a nanomatrix has potential applications in regenerative therapy for Myocardial Infarction (MI). PMID:25521816

  5. Bone tissue remodeling and development: focus on matrix metalloproteinase functions.

    PubMed

    Paiva, Katiucia Batista Silva; Granjeiro, José Mauro

    2014-11-01

    Bone-forming cells originate from distinct embryological layers, mesoderm (axial and appendicular bones) and ectoderm (precursor of neural crest cells, which mainly form facial bones). These cells will develop bones by two principal mechanisms: intramembranous and endochondral ossification. In both cases, condensation of multipotent mesenchymal cells occurs, at the site of the future bone, which differentiate into bone and cartilage-forming cells. During long bone development, an initial cartilaginous template is formed and replaced by bone in a coordinated and refined program involving chondrocyte proliferation and maturation, vascular invasion, recruitment of adult stem cells and intense remodeling of cartilage and bone matrix. Matrix metalloproteinases (MMPs) are the most important enzymes for cleaving structural components of the extracellular matrix (ECM), as well as other non-ECM molecules in the ECM space, pericellular perimeter and intracellularly. Thus, the bioactive molecules generated act on several biological events, such as development, tissue remodeling and homeostasis. Since the discovery of collagenase in bone cells, more than half of the MMP members have been detected in bone tissues under both physiological and pathological conditions. Pivotal functions of MMPs during development and bone regeneration have been revealed by knockout mouse models, such as chondrocyte proliferation and differentiation, osteoclast recruitment and function, bone modeling, coupling of bone resorption and formation (bone remodeling), osteoblast recruitment and survival, angiogenesis, osteocyte viability and function (biomechanical properties); as such alterations in MMP function may alter bone quality. In this review, we look at the principal properties of MMPs and their inhibitors (TIMPs and RECK), provide an up-date on their known functions in bone development and remodeling and discuss their potential application to Bone Bioengineering. PMID:25157440

  6. Applications of coronoid process as a bone graft in maxillofacial surgery.

    PubMed

    Sabhlok, Samrat; Waknis, Pushkar P; Gadre, Kiran S

    2014-03-01

    The coronoid process can be easily harvested as a donor bone by an intraoral approach during many maxillofacial surgery procedures. The purpose of this study was to evaluate the utility of autogenous coronoid process bone grafts for maxillofacial reconstructive surgery. Twelve patients, who underwent coronoid process grafts for reconstruction of maxillofacial deformities due to trauma, alveolar atrophy, or temporomandibular joint ankylosis, were included in the study. There were 3 orbital defects after extended maxillectomy, 1 blowout fracture of the orbit, 2 cases of reconstruction after temporomandibular joint ankylosis surgery, 1 case of additional chin augmentation following horizontal flip genioplasty, 1 defect of anterior wall of maxilla due to trauma, 2 mandibular defects, and 2 cases of bone augmentation for implants.We recommend the use of coronoid process of the mandible as a source for autogenous bone graft as it can provide sufficient bone in quantity and quality for selected maxillofacial reconstructions. PMID:24621702

  7. Fabrication of alumina porous scaffolds with aligned oriented pores for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Sarhadi, Fatemeh; Shafiee Afarani, Mahdi; Mohebbi-Kalhori, Davod; Shayesteh, Masoud

    2016-04-01

    In the present study, porous alumina scaffolds with specific orientation and anisotropic properties are fabricated for application in bone tissue repair. The scaffolds with double shape pores, tubular oriented and isotropic rounded pores, were prepared using alumina and silica as starting materials by the slip casting route. Milled polyurethane foam and silk fibers were applied as replica materials as well. The effect of fiber types and diameter and number of fibers on the microstructure and pore size was studied. Moreover, different characteristics such as porosity, density, orientation, flexural strength and compressive strength of the samples were investigated. Results showed that various fibers with different diameters and numbers led to forming the pores with different pore sizes, microstructure and consequently changes in the physical and mechanical properties. In addition, the simultaneous presence of fibers and particles led to more porous scaffolds. The oriented tiny micro-tube and rounded pores were observed in all porous ceramic scaffolds. Mechanical testing showed an anisotropy in the mechanical behaviors such that higher strengths were observed in the oriented pore direction than that of transverse. With increasing the number and diameter of silk fibers, the scaffolds with a high porosity up to 68 vol% and proper flexural strength were obtained.

  8. Effect of different storage media on the regenerative potential of autogenous bone grafts: a histomorphometrical analysis in rabbits.

    PubMed

    Rocha, Flaviana Soares; Batista, Jonas Dantas; Zanetta-Barbosa, Darceny; Dechichi, Paula

    2013-12-01

    The success of autogenous bone graft is related to the graft cell viability. In bone-grafting procedures, harvested grafts are often maintained in extraoral media while the recipient site is prepared. The aim of this study was to evaluate in vivo the effect of storage media over autogenous bone grafts during the transsurgical time. Two grafts were removed bilaterally from the calvaria of 18 rabbits. One graft was immediately fixed in the mandibular angle (control group), and the other was maintained in air exposure (dry group), 0.9% NaCl solution (saline group), or platelet-poor plasma (PPP group) during 30 minutes and stabilized in the symmetrical location of control grafts. After 28 days, the animals were euthanized and the bone fragments were removed, demineralized, and embedded in paraffin. Histological evaluation was performed under light microscope. Empty lacunae and bone graft area quantification were carried out for the sections. The histomorphometrical analysis revealed reduction of the graft area and increase of empty lacunae in the dry group when compared with control. No significant differences were found in the number of empty lacunae or bone graft area between the saline group and its control and also between the PPP group and its control. The dry group showed more empty lacunae and less graft area than the saline and PPP groups. In accordance with the results, PPP and physiologic solution demonstrated osteocyte preservation and bone graft area maintenance, being satisfactory storage media for autogenous bone grafts during the transsurgical period. PMID:21905882

  9. In situ synthesised TiO2-chitosan-chondroitin 4-sulphate nanocomposites for bone implant applications.

    PubMed

    Alex, Martina Jenitha; Periasamy, Prabu; Mohan, Kalirajan; Sekar, Sankar; Prabha, Kavitha Kandiah Suriya; Venkatachalam, Rajendran

    2016-06-01

    The artificial materials for bone implant applications are gaining more importance in the recent years. The series titania-chitosan-chondroitin 4-sulphate nanocomposites of three different concentrations (2:1:x, where x- 0.125, 0.25, 0.5) have been synthesised by in situ sol-gel method and characterised by various techniques. The particle size of the nanocomposites ranges from 30-50 nm. The bioactivity, swelling nature, and the antimicrobial nature of the nanocomposites were investigated. The swelling ability and bioactivity of the composites is significantly greater and they possess high zone of inhibition against the microorganisms such as Staphylococcus aureus and Escherichia coli. The cell viability of the nanocomposites were evaluated by using MG-63 and observed the composites possess high cell viability at low concentration. The excellent bioactivity and biocompatibility makes these nanocomposites a promising biomaterial for bone implant applications. PMID:27256888

  10. Nanotechnology in meat processing and packaging: potential applications - a review.

    PubMed

    Ramachandraiah, Karna; Han, Sung Gu; Chin, Koo Bok

    2015-02-01

    Growing demand for sustainable production, increasing competition and consideration of health concerns have led the meat industries on a path to innovation. Meat industries across the world are focusing on the development of novel meat products and processes to meet consumer demand. Hence, a process innovation, like nanotechnology, can have a significant impact on the meat processing industry through the development of not only novel functional meat products, but also novel packaging for the products. The potential benefits of utilizing nanomaterials in food are improved bioavailability, antimicrobial effects, enhanced sensory acceptance and targeted delivery of bioactive compounds. However, challenges exist in the application of nanomaterials due to knowledge gaps in the production of ingredients such as nanopowders, stability of delivery systems in meat products and health risks caused by the same properties which also offer the benefits. For the success of nanotechnology in meat products, challenges in public acceptance, economics and the regulation of food processed with nanomaterials which may have the potential to persist, accumulate and lead to toxicity need to be addressed. So far, the most promising area for nanotechnology application seems to be in meat packaging, but the long term effects on human health and environment due to migration of the nanomaterials from the packaging needs to be studied further. The future of nanotechnology in meat products depends on the roles played by governments, regulatory agencies and manufacturers in addressing the challenges related to the application of nanomaterials in food. PMID:25557827

  11. Thermophotovoltaic potential applications for civilian and industrial use in Japan

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hiromi; Yamaguchi, Masafumi

    1999-03-01

    Investigative research on potential market for TPV power sources in Japan has been focused on how TPV can contribute to energy conservation and environmental protection and harmony. The application needs for TPV were surveyed in comparison with conventional engine or turbine generators and developing power generation technologies such as fuel cells or chemical batteries, etc. The investigation on the performance of commercial generators shows that regarding system efficiency, TPV can compete with conventional generators in the output power class of tens of kW. According to the sales for small scale generators in Japan, most of the generators below 10 kW class are utilized mainly for construction, communication, leisure, and that 10-100 kW class generators are for cogeneration in small buildings. Waste heat recovery in dispersed furnaces is another potential application of compact TPV cells. Exhaust heat from small scale incinerators and industrial furnaces is undesirable to be recorded into electricity due to excessive heat loss of the smaller steam turbine generators. Solar powered TPV is also of our concern as a natural energy use. From the viewpoint of applicability for TPV, portable generators cogeneration systems, and solar power plants were selected for our system consideration. Intermediate report on the feasibility study concerning such TPV systems is given as well as the review of the current status of competing power generation technologies in Japan.

  12. Bone scan appearances following bone and bone marrow biopsy

    SciTech Connect

    McKillop, J.H.; Maharaj, D.; Boyce, B.F.; Fogelman, I.

    1984-01-01

    Bone marrow and bone biopsies are performed not infrequently in patients referred for bone scans and represent a potential cause of a ''false positive'' focal abnormality on the bone scan. The authors have therefore examined the scan appearances in a series of patients who had undergone either sternal marrow biopsy, (Salah needle, diameter 1.2 mm) trephine iliac crest marrow biopsy (Jamshidi 11 gauge needle, diameter 3.5 mm) or a transiliac bone biopsy (needle diameter 8 mm). Of 18 patients studied 1 to 45 days after sternal marrow 17 had normal scan appearances at the biopsy site and 1 had a possible abnormality. None of 9 patients studied 4 to 19 days after trephine iliac crest marrow biopsy had a hot spot at the biopsy site. A focal scan abnormality was present at the biopsy site in 9/11 patients studied 5 to 59 days after a trans iliac bone biopsy. No resultant scan abnormality was seen in 4 patients imaged within 3 days of the bone biopsy or in 3 patients imaged 79 to 138 days after the procedure. Bone marrow biopsy of the sternum or iliac crest does not usually cause bone scan abnormalities. A focal abnormality at the biopsy site is common in patients imaged 5 days to 2 months after bone biopsy. The gauge of the needle employed in the biopsy and thus the degree of bone trauma inflicted, is likely to be main factor determining the appearance of bone scan abnormalities at the biopsy site.

  13. Recent Advances in Biosensor Technology for Potential Applications - An Overview.

    PubMed

    Vigneshvar, S; Sudhakumari, C C; Senthilkumaran, Balasubramanian; Prakash, Hridayesh

    2016-01-01

    Imperative utilization of biosensors has acquired paramount importance in the field of drug discovery, biomedicine, food safety standards, defense, security, and environmental monitoring. This has led to the invention of precise and powerful analytical tools using biological sensing element as biosensor. Glucometers utilizing the strategy of electrochemical detection of oxygen or hydrogen peroxide using immobilized glucose oxidase electrode seeded the discovery of biosensors. Recent advances in biological techniques and instrumentation involving fluorescence tag to nanomaterials have increased the sensitive limit of biosensors. Use of aptamers or nucleotides, affibodies, peptide arrays, and molecule imprinted polymers provide tools to develop innovative biosensors over classical methods. Integrated approaches provided a better perspective for developing specific and sensitive biosensors with high regenerative potentials. Various biosensors ranging from nanomaterials, polymers to microbes have wider potential applications. It is quite important to integrate multifaceted approaches to design biosensors that have the potential for diverse usage. In light of this, this review provides an overview of different types of biosensors being used ranging from electrochemical, fluorescence tagged, nanomaterials, silica or quartz, and microbes for various biomedical and environmental applications with future outlook of biosensor technology. PMID:26909346

  14. Adaptive coded aperture imaging: progress and potential future applications

    NASA Astrophysics Data System (ADS)

    Gottesman, Stephen R.; Isser, Abraham; Gigioli, George W., Jr.

    2011-09-01

    Interest in Adaptive Coded Aperture Imaging (ACAI) continues to grow as the optical and systems engineering community becomes increasingly aware of ACAI's potential benefits in the design and performance of both imaging and non-imaging systems , such as good angular resolution (IFOV), wide distortion-free field of view (FOV), excellent image quality, and light weight construct. In this presentation we first review the accomplishments made over the past five years, then expand on previously published work to show how replacement of conventional imaging optics with coded apertures can lead to a reduction in system size and weight. We also present a trade space analysis of key design parameters of coded apertures and review potential applications as replacement for traditional imaging optics. Results will be presented, based on last year's work of our investigation into the trade space of IFOV, resolution, effective focal length, and wavelength of incident radiation for coded aperture architectures. Finally we discuss the potential application of coded apertures for replacing objective lenses of night vision goggles (NVGs).

  15. Potential biodefense model applications for portable chlorine dioxide gas production.

    PubMed

    Stubblefield, Jeannie M; Newsome, Anthony L

    2015-01-01

    Development of decontamination methods and strategies to address potential infectious disease outbreaks and bioterrorism events are pertinent to this nation's biodefense strategies and general biosecurity. Chlorine dioxide (ClO2) gas has a history of use as a decontamination agent in response to an act of bioterrorism. However, the more widespread use of ClO2 gas to meet current and unforeseen decontamination needs has been hampered because the gas is too unstable for shipment and must be prepared at the application site. Newer technology allows for easy, onsite gas generation without the need for dedicated equipment, electricity, water, or personnel with advanced training. In a laboratory model system, 2 unique applications (personal protective equipment [PPE] and animal skin) were investigated in the context of potential development of decontamination protocols. Such protocols could serve to reduce human exposure to bacteria in a decontamination response effort. Chlorine dioxide gas was capable of reducing (2-7 logs of vegetative and spore-forming bacteria), and in some instances eliminating, culturable bacteria from difficult to clean areas on PPE facepieces. The gas was effective in eliminating naturally occurring bacteria on animal skin and also on skin inoculated with Bacillus spores. The culturable bacteria, including Bacillus spores, were eliminated in a time- and dose-dependent manner. Results of these studies suggested portable, easily used ClO2 gas generation systems have excellent potential for protocol development to contribute to biodefense strategies and decontamination responses to infectious disease outbreaks or other biothreat events. PMID:25812425

  16. Therapeutic Potential of Gingival Fibroblasts for Cutaneous Radiation Syndrome: Comparison to Bone Marrow-Mesenchymal Stem Cell Grafts

    PubMed Central

    Tissedre, Frederique; Busson, Elodie; Holler, Valerie; Leclerc, Thomas; Strup-Perrot, Carine; Couty, Ludovic; L'homme, Bruno; Benderitter, Marc; Lafont, Antoine; Lataillade, Jean Jacques; Coulomb, Bernard

    2015-01-01

    Mesenchymal stem cell (MSC) therapy has recently been investigated as a potential treatment for cutaneous radiation burns. We tested the hypothesis that injection of local gingival fibroblasts (GFs) would promote healing of radiation burn lesions and compared results with those for MSC transplantation. Human clinical- grade GFs or bone marrow-derived MSCs were intradermally injected into mice 21 days after local leg irradiation. Immunostaining and real-time PCR analysis were used to assess the effects of each treatment on extracellular matrix remodeling and inflammation in skin on days 28 and 50 postirradiation. GFs induced the early development of thick, fully regenerated epidermis, skin appendages, and hair follicles, earlier than MSCs did. The acceleration of wound healing by GFs involved rearrangement of the deposited collagen, modification of the Col/MMP/TIMP balance, and modulation of the expression and localization of tenascin-C and of the expression of growth factors (VEGF, EGF, and FGF7). As MSC treatment did, GF injection decreased the irradiation-induced inflammatory response and switched the differentiation of macrophages toward an M2-like phenotype, characterized by CD163+ macrophage infiltration and strong expression of arginase-1. These findings indicate that GFs are an attractive target for regenerative medicine, for easier to collect, can grow in culture, and promote cutaneous wound healing in irradiation burn lesions. PMID:25584741

  17. Comparisons of Differentiation Potential in Human Mesenchymal Stem Cells from Wharton's Jelly, Bone Marrow, and Pancreatic Tissues

    PubMed Central

    Kao, Shih-Yi; Shyu, Jia-Fwu; Wang, Hwai-Shi; Lin, Chi-Hung; Su, Cheng-Hsi; Chen, Tien-Hua; Weng, Zen-Chung; Tsai, Pei-Jiun

    2015-01-01

    Background. Type 1 diabetes mellitus results from autoimmune destruction of β-cells. Insulin-producing cells (IPCs) differentiated from mesenchymal stem cells (MSCs) in human tissues decrease blood glucose levels and improve survival in diabetic rats. We compared the differential ability and the curative effect of IPCs from three types of human tissue to determine the ideal source of cell therapy for diabetes. Methods. We induced MSCs from Wharton's jelly (WJ), bone marrow (BM), and surgically resected pancreatic tissue to differentiate into IPCs. The in vitro differential function of these IPCs was compared by insulin-to-DNA ratios and C-peptide levels after glucose challenge. In vivo curative effects of IPCs transplanted into diabetic rats were monitored by weekly blood glucose measurement. Results. WJ-MSCs showed better proliferation and differentiation potential than pancreatic MSCs and BM-MSCs. In vivo, WJ-IPCs significantly reduced blood glucose levels at first week after transplantation and maintained significant decrease till week 8. BM-IPCs reduced blood glucose levels at first week but gradually increased since week 3. In resected pancreas-IPCs group, blood glucose levels were significantly reduced till two weeks after transplantation and gradually increased since week 4. Conclusion. WJ-MSCs are the most promising stem cell source for β-cell regeneration in diabetes treatment. PMID:26294917

  18. Cervical and ocular vestibular-evoked myogenic potentials in vestibular neuritis: comparison between air- and bone-conducted stimulation.

    PubMed

    Oh, Sun-Young; Kim, Ji-Soo; Yang, Tae-Ho; Shin, Byoung-Soo; Jeong, Seul-Ki

    2013-08-01

    To clarify the changes of cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials induced by air-conducted sound (ACS) and bone-conducted vibration (BCV) in patients with vestibular neuritis (VN), patients with VN (n = 30) and normal controls (n = 45) underwent recording of cVEMP and oVEMP in response to ACS (1,000 Hz, 5 ms, tone bursts) and BCV (500 Hz, short tone burst). Patients with VN showed a high proportion of oVEMP abnormalities in response to both ACS (80.0 %) and BCV at the forehead (Fz, 73.3 %) or the mastoid (76.7 %). In contrast, cVEMPs were mostly normal with both ACS and BCV in the patients. The dissociations in the abnormalities of cVEMP and oVEMP induced by ACS and BCV at the mastoids and at the forehead in patients with VN suggest that oVEMP reflects functions of the superior vestibular nerve and most likely the utricular function. The results of our study suggest that oVEMP induced by either ACS or BCV appears to depend on integrity of the superior vestibular nerve, possibly due to the utricular afferents travelling in it. In contrast, cVEMP elicited by either ACS or BCV may reflect function of the saccular afferents running in the inferior vestibular nerve. PMID:23670310

  19. Activation of the germ-cell potential of human bone marrow-derived cells by a chemical carcinogen

    PubMed Central

    Liu, Chunfang; Ma, Zhan; Xu, Songtao; Hou, Jun; Hu, Yao; Yu, Yinglu; Liu, Ruilai; Chen, Zhihong; Lu, Yuan

    2014-01-01

    Embryonic/germ cell traits are common in malignant tumors and are thought to be involved in malignant tumor behaviors. The reasons why tumors show strong embryonic/germline traits (displaced germ cells or gametogenic programming reactivation) are controversial. Here, we show that a chemical carcinogen, 3-methyl-cholanthrene (3-MCA), can trigger the germ-cell potential of human bone marrow-derived cells (hBMDCs). 3-MCA promoted the generation of germ cell-like cells from induced hBMDCs that had undergone malignant transformation, whereas similar results were not observed in the parallel hBMDC culture at the same time point. The malignant transformed hBMDCs spontaneously and more efficiently generated into germ cell-like cells even at the single-cell level. The germ cell-like cells from induced hBMDCs were similar to natural germ cells in many aspects, including morphology, gene expression, proliferation, migration, further development, and teratocarcinoma formation. Therefore, our results demonstrate that a chemical carcinogen can reactivate the germline phenotypes of human somatic tissue-derived cells, which might provide a novel idea to tumor biology and therapy. PMID:24998261

  20. In Vitro and In Vivo Characterization of Pentaerythritol Triacrylate-co-Trimethylolpropane Nanocomposite Scaffolds as Potential Bone Augments and Grafts

    PubMed Central

    Chen, Cong; Garber, Leah; Smoak, Mollie; Fargason, Carmel; Scherr, Thomas; Blackburn, Caleb; Bacchus, Sasha; Lopez, Mandi J.; Pojman, John A.; Del Piero, Fabio

    2015-01-01

    A thiol-acrylate-based copolymer synthesized via an amine-catalyzed Michael addition was studied in vitro and in vivo to assess its potential as an in situ polymerizing graft or augment in bone defect repair. The blends of hydroxyapatite (HA) with pentaerythritol triacrylate-co-trimethylolpropane (PETA), cast as solids or gas foamed as porous scaffolds, were evaluated in an effort to create a biodegradable osteogenic material for use as a bone-void-filling augment. Osteogenesis experiments were conducted with human adipose-derived mesenchymal stromal cells (hASCs) to determine the ability of the material to serve as an osteoinductive substrate. Poly(ɛ-caprolactone) (PCL) composites PCL:HA (80:20) (wt/wt%) served as the control scaffold, while the experimental scaffolds included PETA:HA (100:0), (85:15), (80:20), and (75:25) composites (wt/wt%). The results indicate that PETA:HA (80:20) foam composites had higher mechanical strength than the corresponding porous PCL:HA (80:20) scaffolds made by thermo-precipitation method, and in the case of foamed composites, increasing HA content directly correlated with increased yield strength. For cytotoxicity and osteogenesis experiments, hASCs cultured for 21 days on PETA:HA scaffolds in stromal medium displayed the greatest number of live cells compared with PCL:HA composites. Moreover, hASCs cultured on foamed PETA:HA (80:20) scaffolds resulted in the greatest mineralization, increased alkaline phosphatase (ALP) expression, and the highest osteocalcin (OCN) expression after 21 days. Overall, the PETA:HA (80:20) and PETA:HA (85:15) scaffolds, with 66.38% and 72.02% porosity, respectively, had higher mechanical strength and cytocompatibility compared with the PCL:HA control. The results of the 6-week in vivo biocompatibility study using a posterior lumbar spinal fusion model demonstrate that PETA:HA can be foamed in vivo without serious adverse effects at the surgical site. Additionally, it was demonstrated that cells

  1. In vitro and in vivo characterization of pentaerythritol triacrylate-co-trimethylolpropane nanocomposite scaffolds as potential bone augments and grafts.

    PubMed

    Chen, Cong; Garber, Leah; Smoak, Mollie; Fargason, Carmel; Scherr, Thomas; Blackburn, Caleb; Bacchus, Sasha; Lopez, Mandi J; Pojman, John A; Del Piero, Fabio; Hayes, Daniel J

    2015-01-01

    A thiol-acrylate-based copolymer synthesized via an amine-catalyzed Michael addition was studied in vitro and in vivo to assess its potential as an in situ polymerizing graft or augment in bone defect repair. The blends of hydroxyapatite (HA) with pentaerythritol triacrylate-co-trimethylolpropane (PETA), cast as solids or gas foamed as porous scaffolds, were evaluated in an effort to create a biodegradable osteogenic material for use as a bone-void-filling augment. Osteogenesis experiments were conducted with human adipose-derived mesenchymal stromal cells (hASCs) to determine the ability of the material to serve as an osteoinductive substrate. Poly(ɛ-caprolactone) (PCL) composites PCL:HA (80:20) (wt/wt%) served as the control scaffold, while the experimental scaffolds included PETA:HA (100:0), (85:15), (80:20), and (75:25) composites (wt/wt%). The results indicate that PETA:HA (80:20) foam composites had higher mechanical strength than the corresponding porous PCL:HA (80:20) scaffolds made by thermo-precipitation method, and in the case of foamed composites, increasing HA content directly correlated with increased yield strength. For cytotoxicity and osteogenesis experiments, hASCs cultured for 21 days on PETA:HA scaffolds in stromal medium displayed the greatest number of live cells compared with PCL:HA composites. Moreover, hASCs cultured on foamed PETA:HA (80:20) scaffolds resulted in the greatest mineralization, increased alkaline phosphatase (ALP) expression, and the highest osteocalcin (OCN) expression after 21 days. Overall, the PETA:HA (80:20) and PETA:HA (85:15) scaffolds, with 66.38% and 72.02% porosity, respectively, had higher mechanical strength and cytocompatibility compared with the PCL:HA control. The results of the 6-week in vivo biocompatibility study using a posterior lumbar spinal fusion model demonstrate that PETA:HA can be foamed in vivo without serious adverse effects at the surgical site. Additionally, it was demonstrated that cells

  2. Potential Applications of an Integrated Seismic, Tilt, and Temperature Instrument

    NASA Astrophysics Data System (ADS)

    Bainbridge, Geoffrey; Parker, Tim; Karimi, Sepideh; Devanney, Peter

    2016-04-01

    Force feedback seismometers provide mass position outputs which represent the time-averaged feedback force applied to each inertial mass, in order to cancel external forces and keep it balanced at its center point. These external forces are primarily due to tilt and temperature. In a symmetric triaxial seismometer, tilt and temperature effects can be distinguished because temperature affects all 3 axes equally whereas tilt causes a different force on each axis. This study analyzes the resolution of tilt and temperature signals that can be obtained from a force-feedback seismometer, and the potential applicability of this data to applications such as volcano monitoring and cap rock integrity monitoring. Also the synergy of a combined seismic, tilt, and temperature instrument is considered.

  3. Graphene-plasmon polaritons: From fundamental properties to potential applications

    NASA Astrophysics Data System (ADS)

    Xiao, Sanshui; Zhu, Xiaolong; Li, Bo-Hong; Mortensen, N. Asger

    2016-04-01

    With unique possibilities for controlling light in nanoscale devices, graphene plasmonics has opened new perspectives to the nanophotonics community with potential applications in metamaterials, modulators, photodetectors, and sensors. In this paper, we briefly review the recent exciting progress in graphene plasmonics. We begin with a general description of the optical properties of graphene, particularly focusing on the dispersion of graphene-plasmon polaritons. The dispersion relation of graphene-plasmon polaritons of spatially extended graphene is expressed in terms of the local response limit with an intraband contribution. With this theoretical foundation of graphene-plasmon polaritons, we then discuss recent exciting progress, paying specific attention to the following topics: excitation of graphene plasmon polaritons, electron-phonon interactions in graphene on polar substrates, and tunable graphene plasmonics with applications in modulators and sensors. Finally, we address some of the apparent challenges and promising perspectives of graphene plasmonics.

  4. Precision bone and muscle loss measurements by advanced, multiple projection DEXA (AMPDXA) techniques for spaceflight applications

    NASA Technical Reports Server (NTRS)

    Charles, H. K. Jr; Beck, T. J.; Feldmesser, H. S.; Magee, T. C.; Spisz, T. S.; Pisacane, V. L.

    2001-01-01

    An advanced, multiple projection, dual energy x-ray absorptiometry (AMPDXA) scanner system is under development. The AMPDXA is designed to make precision bone and muscle loss measurements necessary to determine the deleterious effects of microgravity on astronauts as well as develop countermeasures to stem their bone and muscle loss. To date, a full size test system has been developed to verify principles and the results of computer simulations. Results indicate that accurate predictions of bone mechanical properties can be determined from as few as three projections, while more projections are needed for a complete, three-dimensional reconstruction. c 2001. Elsevier Science Ltd. All rights reserved.

  5. Green synthesis of nanoparticles and its potential application.

    PubMed

    Hussain, Imtiyaz; Singh, N B; Singh, Ajey; Singh, Himani; Singh, S C

    2016-04-01

    Nanotechnology is a new and emerging technology with wealth of applications. It involves the synthesis and application of materials having one of the dimensions in the range of 1-100 nm. A wide variety of physico-chemical approaches are being used these days for the synthesis of nanoparticles (NPs). However, biogenic reduction of metal precursors to produce corresponding NPs is eco-friendly, less expensive, free of chemical contaminants for medical and biological applications where purity of NPs is of major concern. Biogenic reduction is a "Bottom Up" approach similar to chemical reduction where a reducing agent is replaced by extract of a natural products with inherent stabilizing, growth terminating and capping properties. Furthermore, the nature of biological entities in different concentrations in combination with reducing organic agents influence the size and shape of NPs. Present review focuses on microbes or plants based green synthesis of Ag, Au, Cu, Fe, Pd, Ru, PbS, CdS, CuO, CeO2, Fe3O4, TiO2, and ZnO NPs and their potential applications. PMID:26721237

  6. Genistein induces adipogenic differentiation in human bone marrow mesenchymal stem cells and suppresses their osteogenic potential by upregulating PPARγ

    PubMed Central

    ZHANG, LI-YAN; XUE, HAO-GANG; CHEN, JI-YING; CHAI, WEI; NI, MING

    2016-01-01

    Genistein is a soy isoflavone that exists in the form of an aglycone. It is the primary active component in soy isoflavone and has a number of biological activities (anti-inflammatory and anti-oxidative). However, the specific effect of genistein on human bone marrow mesenchymal stem cells (BMSCs) remains unclear. In the present study, the mechanism underlying the effect of genistein on the suppression of BMSC adipogenic differentiation and the enhancement of osteogenic potential was investigated using an MTT assay. It was observed that genistein significantly increased BMSC cell proliferation in a time- and dose-dependent manner (P<0.01). In addition, reverse transcription-quantitative polymerase chain reaction revealed that genistein significantly inhibited the expression of runt-related transcription factor 2 (Runx2), type I collagen (Col I) and osteocalcin (OC; P<0.01). Furthermore, 20 µm genistein significantly inhibited the activity of alkaline phosphatase (ALP) and increased the activity of triglycerides (TGs) increased (P<0.01) as determined by an enzyme-linked immunosorbent assay. Finally, western blotting revealed that BMSC pretreatment with 20 µm genistein significantly increased peroxisome proliferator-activated receptor γ (PPARγ) protein expression (P<0.01). This suggests that the downregulation of PPARγ may significantly reduce the effect of genistein on cell proliferation, suppress the expression of Runx2, Col I and OC mRNA, and reduce ALP and promote TG activity in BMSCs. Thus, the results of the present study conclude that genistein induces adipogenic differentiation in human BMSCs and suppresses their osteogenic potential by upregulating the expression of PPARγ. In conclusion, genistein may be a promising candidate drug for treatment against osteogenesis. PMID:27168816

  7. Fructo-oligosaccharides: Production, Purification and Potential Applications.

    PubMed

    Bali, Vandana; Panesar, Parmjit S; Bera, Manab B; Panesar, Reeba

    2015-01-01

    The nutritional and therapeutic benefits of prebiotics have attracted the keen interest of consumers and food processing industry for their use as food ingredients. Fructo-oligosaccharides (FOS), new alternative sweeteners, constitute 1-kestose, nystose, and 1-beta-fructofuranosyl nystose produced from sucrose by the action of fructosyltransferase from plants, bacteria, yeast, and fungi. FOS has low caloric values, non-cariogenic properties, and help gut absorption of ions, decrease levels of lipids and cholesterol and bifidus-stimulating functionality. The purified linear fructose oligomers are added to various food products like cookies, yoghurt, infant milk products, desserts, and beverages due to their potential health benefits. This review is focused on the various aspects of biotechnological production, purification and potential applications of fructo-oligosaccharides. PMID:24915337

  8. Clinical application of vestibular evoked myogenic potential (VEMP).

    PubMed

    Murofushi, Toshihisa

    2016-08-01

    The author reviewed clinical aspects of vestibular evoked myogenic potentials (VEMPs). Now two types of VEMPs are available. The first one is cervical VEMP, which is recorded in the sternocleidomastoid muscle and predominantly reflects sacculo-collic reflex. The other is ocular VEMP, which is usually recorded below the lower eye lid and predominantly reflects utriculo-ocular reflex. VEMPs play important roles not only for assessment of common vestibular diseases but also for establishment of new clinical entities. Clinical application in Meniere's disease, vestibular neuritis, benign paroxysmal positional vertigo, vestibular migraine, idiopathic otolithic vertigo, and central vertigo/dizziness was reviewed. PMID:26791591

  9. A New Scheme for Probabilistic Teleportation and Its Potential Applications

    NASA Astrophysics Data System (ADS)

    Wei, Jia-Hua; Dai, Hong-Yi; Zhang, Ming

    2013-12-01

    We propose a novel scheme to probabilistically teleport an unknown two-level quantum state when the information of the partially entangled state is only available for the sender. This is in contrast with the fact that the receiver must know the non-maximally entangled state in previous typical schemes for the teleportation. Additionally, we illustrate two potential applications of the novel scheme for probabilistic teleportation from a sender to a receiver with the help of an assistant, who plays distinct roles under different communication conditions, and our results show that the novel proposal could enlarge the applied range of probabilistic teleportation.

  10. Potential applications of an electron cyclotron resonance multicusp plasma source

    SciTech Connect

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Stirling, W.L.

    1989-01-01

    An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produced large (about 25-cm-diam), uniform (to within {plus minus}10%), dense (>10{sup 11}-cm{sup -3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR plasma source for plasma processing of thin films are discussed. 21 refs., 10 figs.

  11. Bone Diseases

    MedlinePlus

    ... avoid smoking and drinking too much alcohol. Bone diseases can make bones easy to break. Different kinds ... break Osteogenesis imperfecta makes your bones brittle Paget's disease of bone makes them weak Bones can also ...

  12. Application potential of toll-like receptors in cancer immunotherapy

    PubMed Central

    Shi, Ming; Chen, Xi; Ye, Kangruo; Yao, Yuanfei; Li, Yu

    2016-01-01

    Abstract Toll-like receptors (TLRs), as the most important pattern recognition receptors in innate immunity, play a pivotal role in inducing immune response through recognition of microbial invaders or specific agonists. Recent studies have suggested that TLRs could serve as important regulators in the development of a variety of cancer. However, increasing evidences have shown that TLRs may display quite opposite outcomes in cancer development. Although several potential therapeutic Toll-like receptor ligands have been found, the mechanism and therapy prospect of TLRs in cancer development has to be further elucidated to accelerate the clinical application. By performing a systematic review of the present findings on TLRs in cancer immunology, we attempted to evaluate the therapeutic potential of TLRs in cancer therapy and elucidate the potential mechanism of cancer progress regulated by TLR signaling and the reported targets on TLRs for clinical application. An electronic databases search was conducted in PubMed, Chinese Scientific Journal Database, and Chinese Biomedical Literature Database from their inception to February 1, 2016. The following keywords were used to search the databases: Toll-like receptors, cancer therapy, therapeutic target, innate immunity. Of 244 studies that were identified, 97 nonrelevant studies were excluded. In total, 147 full-text articles were assessed, and from these, 54 were excluded as they did not provide complete key information. Thus, 93 studies were considered eligible and included in the analysis. According to the data from the included trials, 14 TLR ligands (77.8%) from 82 studies have been demonstrated to display antitumor property in various cancers, whereas 4 ligands (22.2%) from 11 studies promote tumors. Among them, only 3 TLR ligands have been approved for cancer therapy, and 9 ligands were in clinical trials. In addition, the potential mechanism of recently reported targets on TLRs for clinical application was also

  13. Targeted gene correction in the mdx mouse using short DNA fragments: towards application with bone marrow-derived cells for autologous remodeling of dystrophic muscle.

    PubMed

    Kapsa, R M; Quigley, A F; Vadolas, J; Steeper, K; Ioannou, P A; Byrne, E; Kornberg, A J

    2002-06-01

    In muscle, mutant genes can be targeted and corrected directly by intramuscular (i.m.) injection of corrective DNA, or by ex vivo delivery of DNA to myogenic cells, followed by cell transplantation. Short fragment homologous replacement (SFHR) has been used to repair the exon 23 nonsense transition at the Xp21.1 dys locus in cultured cells and also, directly in tibialis anterior from male mdx mice. Whilst mdx dys locus correction can be achieved in up to 20% of cells in culture, much lower efficiency is evident by i.m. injection. The major consideration for application of targeted gene correction to muscle is delivery throughout relevant tissues. Systemically injected bone marrow (BM)-derived cells from wt C57BL/10 ScSn mice are known to remodel mdx muscle when injected into the systemic route. Provided that non muscle-derived cell types most capable of muscle remodeling activity can be more specifically identified, isolated and expanded, cell therapy seems presently the most favorable vehicle by which to deliver gene correction throughout muscle tissues. Using wt bone marrow as a model, this study investigates systemic application of bone marrow-derived cells as potential vehicles to deliver corrected (ie wt) dys locus to dystrophic muscle. Intravenous (i.v.) and intraperitoneal (i.p.) injections of wt BM were given to lethally and sub-lethally irradiated mdx mice. Despite both i.v. and surviving i.p. groups containing wt dys loci in 100% and less than 1% of peripheral blood nuclei, respectively, both groups displayed equivalent levels of wt dys transcript in muscle RNA. These results suggest that the muscle remodeling activity observed in systemically injected BM cells is not likely to be found in the hemopoietic fraction. PMID:12032690

  14. Anorexia nervosa and bone.

    PubMed

    Misra, Madhusmita; Klibanski, Anne

    2014-06-01

    Anorexia nervosa (AN) is a condition of severe low weight that is associated with low bone mass, impaired bone structure, and reduced bone strength, all of which contribute to increased fracture risk. Adolescents with AN have decreased rates of bone accrual compared with normal-weight controls, raising additional concerns of suboptimal peak bone mass and future bone health in this age group. Changes in lean mass and compartmental fat depots, and hormonal alterations secondary to nutritional factors contribute to impaired bone metabolism in AN. The best strategy to improve bone density is to regain weight and menstrual function. Oral estrogen-progesterone combinations are not effective in increasing bone density in adults or adolescents with AN, and transdermal testosterone replacement is not effective in increasing bone density in adult women with AN. However, physiological estrogen replacement as transdermal estradiol with cyclic progesterone does increase bone accrual rates in adolescents with AN to approximate that in normal-weight controls, leading to a maintenance of bone density Z-scores. A recent study has shown that risedronate increases bone density at the spine and hip in adult women with AN. However, bisphosphonates should be used with great caution in women of reproductive age, given their long half-life and potential for teratogenicity, and should be considered only in patients with low bone density and clinically significant fractures when non-pharmacological therapies for weight gain are ineffective. Further studies are necessary to determine the best therapeutic strategies for low bone density in AN. PMID:24898127

  15. Anorexia Nervosa and Bone

    PubMed Central

    Misra, Madhusmita; Klibanski, Anne

    2014-01-01

    Anorexia nervosa (AN) is a condition of severe low weight that is associated with low bone mass, impaired bone structure and reduced bone strength, all of which contribute to increased fracture risk., Adolescents with AN have decreased rates of bone accrual compared with normal-weight controls, raising addition concerns of suboptimal peak bone mass and future bone health in this age group. Changes in lean mass and compartmental fat depots, hormonal alterations secondary to nutritional factors contribute to impaired bone metabolism in AN. The best strategy to improve bone density is to regain weight and menstrual function. Oral estrogen-progesterone combinations are not effective in increasing bone density in adults or adolescents with AN, and transdermal testosterone replacement is not effective in increasing bone density in adult women with AN. However, physiologic estrogen replacement as transdermal estradiol with cyclic progesterone does increase bone accrual rates in adolescents with AN to approximate that in normal-weight controls, leading to a maintenance of bone density Z-scores. A recent study has shown that risedronate increases bone density at the spine and hip in adult women with AN. However, bisphosphonates should be used with great caution in women of reproductive age given their long half-life and potential for teratogenicity, and should be considered only in patients with low bone density and clinically significant fractures when non-pharmacological therapies for weight gain are ineffective. Further studies are necessary to determine the best therapeutic strategies for low bone density in AN. PMID:24898127

  16. Extracellular polymeric substances of bacteria and their potential environmental applications.

    PubMed

    More, T T; Yadav, J S S; Yan, S; Tyagi, R D; Surampalli, R Y

    2014-11-01

    Biopolymers are considered a potential alternative to conventional chemical polymers because of their ease of biodegradability, high efficiency, non-toxicity and non-secondary pollution. Recently, extracellular polymeric substances (EPS, biopolymers produced by the microorganisms) have been recognised by many researchers as a potential flocculent for their applications in various water, wastewater and sludge treatment processes. In this context, literature information on EPS is widely dispersed and is very scarce. Thus, this review marginalizes various studies conducted so far about EPS nature-production-recovery, properties, environmental applications and moreover, critically examines future research needs and advanced application prospective of the EPS. One of the most important aspect of chemical composition and structural details of different moieties of EPS in terms of carbohydrates, proteins, extracellular DNA, lipid and surfactants and humic substances are described. These chemical characteristics of EPS in relation to formation and properties of microbial aggregates as well as degradation of EPS in the matrix (biomass, flocs etc) are analyzed. The important engineering properties (based on structural characteristics) such as adsorption, biodegradability, hydrophilicity/hydrophobicity of EPS matrix are also discussed in details. Different aspects of EPS production process such as bacterial strain maintenance; inoculum and factors affecting EPS production were presented. The important factors affecting EPS production include growth phase, carbon and nitrogen sources and their ratio, role of other nutrients (phosphorus, micronutrients/trace elements, and vitamins), impact of pH, temperature, metals, aerobic versus anaerobic conditions and pure and mixed culture. The production of EPS in high concentration with high productivity is essential due to economic reasons. Therefore, the knowledge about all the aspects of EPS production (listed above) is highly

  17. Ionizing Radiation and Bone Loss: Space Exploration and Clinical Therapy Applications

    PubMed Central

    Willey, Jeffrey S.; Lloyd, Shane A. J.; Nelson, Gregory A.; Bateman, Ted A.

    2011-01-01

    Damage to normal, nontumor bone tissue following therapeutic irradiation increases the risk of fracture among cancer patients. For example, women treated for various pelvic tumors have been shown to have a greater than 65% increased incidence of hip fracture by 5 years postradiotherapy. Another practical situation in which exposure to ionizing radiation may negatively impact skeletal integrity is during extended spaceflight missions. There is a limited understanding of how spaceflight-relevant doses and types of radiation can influence astronaut bone health, particularly when combined with the significant effects of mechanical unloading experienced in microgravity. Historically, negative effects on osteoblasts have been studied. Radiation exposure has been shown to damage osteoblast precursors. Damage to local vasculature has been observed, ranging from decreased lumen diameter to complete ablation within the irradiated volume, causing a state of hypoxia. These effects result in suppression of bone formation and a general state of low bone turnover. More recently, however, we have demonstrated in pre-clinical mouse models, a very rapid but transient increase in osteoclast activity after exposure to spaceflight and clinically relevant radiation doses. Combined with long-term suppression of bone formation, this skeletal damage may cause long-term deficits. This review will present a broad set of literature outlining our current set knowledge of both clinical therapy and space exploration exposure to ionizing radiation. Additionally, we will discuss prevention of the initial osteoclast-mediated bone loss, the need to promote normal bone turnover and long-term quality of bone tissue, and our hypothesized molecular mechanisms. PMID:22826690

  18. Application of XRF to measure strontium in human bone in vivo

    SciTech Connect

    Wielopolski, L.; Vartsky, D.; Yasumura, S.; Cohn, S.H.

    1982-01-01

    As a basis for better understanding the role that Sr fulfills in human body, it is desirable to measure directly the main Sr store in human body. Although strontium is omnipresent in human tissues, 99% is stored inthe mineral portion of the bone. In the present study x-ray fluorescence (XRF) was applied to measure the strontium content of the tibial shaft in vivo. The feasibility studies showed that normal levels of stable strontium in the bone can be measured successfully.

  19. The iliac bone or osteocutaneous transplant pedicled to the deep circumflex iliac artery. II. Clinical application.

    PubMed

    Bitter, K; Schlesinger, S; Westerman, U

    1983-12-01

    10 patients received a bone or osteocutaneous transplant pedicled to the deep circumflex iliac artery (DCIA) after in-continuity resection of the mandible. 9 grafts healed primarily and were stable after a period of time corresponding to that needed in fractured bones. No infection or resorption occurred. In one case, varicosity made the vessel preparation impossible. Indications, reliability and pitfalls of this method are outlined and discussed in this paper. PMID:6361188

  20. The application of backscattered ultrasound and photoacoustic signals for assessment of bone collagen and mineral contents

    PubMed Central

    Lashkari, Bahman; Yang, Lifeng

    2015-01-01

    Background This study examines the backscattered ultrasound (US) and back-propagating photoacoustic (PA) signals from trabecular bones, and their variations with reduction in bone minerals and collagen content. While the collagen status is directly related to the strength of the bone, diagnosis of its condition using US remains a challenge. Methods For both PA and US methods, coded-excitation signals and matched filtering were utilized to provide high sensitivity of the detected signal. The optical source was a 805-nm CW laser and signals were detected employing a 2.2-MHz ultrasonic transducer. Bone decalcification and decollagenization were induced with mild ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite solutions, respectively. Results The PA and US signals were measured on cattle bones, and apparent integrated backscatter/back-propagating (AIB) parameters were compared before and after demineralization and decollagenization. Conclusions The results show that both PA and US are sensitive to mineral changes. In addition, PA is also sensitive to changes in the collagen content of the bone, but US is not significantly sensitive to these changes. PMID:25694953

  1. The Amniotic Membrane: Development and Potential Applications - A Review.

    PubMed

    Favaron, P O; Carvalho, R C; Borghesi, J; Anunciação, A R A; Miglino, M A

    2015-12-01

    Foetal membranes are essential tissues for embryonic development, playing important roles related to protection, breathing, nutrition and excretion. The amnion is the innermost extraembryonic membrane, which surrounds the foetus, forming an amniotic sac that contains the amniotic fluid (AF). In recent years, the amniotic membrane has emerged as a potential tool for clinical applications and has been primarily used in medicine in order to stimulate the healing of skin and corneal diseases. It has also been used in vaginal reconstructive surgery, repair of abdominal hernia, prevention of surgical adhesions and pericardium closure. More recently, it has been used in regenerative medicine because the amniotic-derived stem cells as well as AF-derived cells exhibit cellular plasticity, angiogenic, cytoprotective, immunosuppressive properties, antitumoural potential and the ability to generate induced pluripotent stem cells. These features make them a promising source of stem cells for cell therapy and tissue engineering. In this review, we discussed the development of the amnion, AF and amniotic cavity in different species, as well as the applicability of stem cells from the amnion and AF in cellular therapy. PMID:26510939

  2. Artificial placenta: Recent advances and potential clinical applications.

    PubMed

    Metelo-Coimbra, Catarina; Roncon-Albuquerque, Roberto

    2016-06-01

    Lung immaturity remains a major cause of morbidity and mortality in extremely premature infants. Positive-pressure mechanical ventilation, the method of choice for respiratory support in premature infants, frequently promotes by itself lung injury and a negative impact in the circulatory function. Extracorporeal lung support has been proposed for more than 50 years as a potential alternative to mechanical ventilation in the treatment of severe respiratory failure of extremely premature infants. Recent advances in this field included the development of miniaturized centrifugal pumps and polymethylpentene oxygenators, as well as the successful use of pump-assisted veno-venous extracorporeal gas exchange systems in experimental artificial placenta models. This review, which includes studies published from 1958 to 2015, presents an update on the artificial placenta concept and its potential clinical applications. Special focus will be devoted to the milestones achieved so far and to the limitations that must be overcome before its clinical application. Notwithstanding, the artificial placenta stands as a promising alternative to mechanical ventilation in extremely premature infants. Pediatr Pulmonol. 2016;51:643-649. © 2016 Wiley Periodicals, Inc. PMID:26915478

  3. Potential applications of SMART Layer technology for homeland security

    NASA Astrophysics Data System (ADS)

    Kumar, Amrita; Wu, H. Felix; Lin, Mark; Beard, Shawn; Qing, Xinlin; Zhang, Chang; Hamilton, Michael; Ikegami, Roy

    2004-07-01

    The SMART Layer (reg. TM) manufactured by Acellent is a thin flexible layer with a network of miniature piezoelectric actuators and sensors that can be embedded inside or mounted onto metal and composite structures to acquire information on structural integrity. Currently, SMART Layers (reg. TM) are used to assess the condition of structures and to monitor impact events. The layers can be used to perform built-in structural inspection by exciting the devices with a periodic or transient burst controlled input and analyzing the corresponding structural response. The technology can also be applied to areas concerned with Homeland Security. For example, the technology can be used for motion monitoring and monitoring of structures used in defense applications. By having a network of sensors that monitor loads on a structure, it is possible to monitor the movement of people by measuring the loads exerted by them. The SMART Layer (reg. TM) technology can be used to enhance the readiness of structures used for homeland defense such as manned and unmanned aircraft, missiles and radar systems. It can also be used to monitor a pipeline network for any terrorist related activity that can potentially damage the pipe system. A brief overview of such potential applications is presented here.

  4. Biomedical potential of chitosan/HA and chitosan/β-1,3-glucan/HA biomaterials as scaffolds for bone regeneration--A comparative study.

    PubMed

    Przekora, Agata; Palka, Krzysztof; Ginalska, Grazyna

    2016-01-01

    The aim of this work was to compare biomedical potential of chitosan/hydroxyapatite (chit/HA) and novel chitosan/β-1,3-glucan/hydroxyapatite (chit/glu/HA) materials as scaffolds for bone regeneration via characterization of their biocompatibility, porosity, mechanical properties, and water uptake behaviour. Biocompatibility of the scaffolds was assessed in direct-contact with the materials using normal human foetal osteoblast cell line. Cytotoxicity and osteoblast proliferation rate were evaluated. Porosity was assessed using computed microtomography analysis and mechanical properties were determined by compression testing. Obtained results demonstrated that chit/HA scaffold possessed significantly better mechanical properties (compressive strength: 1.23 MPa, Young's modulus: 0.46 MPa) than chit/glu/HA material (compressive strength: 0.26 MPa, Young's modulus: 0.25 MPa). However, addition of bacterial β-1,3-glucan to the chit/HA scaffold improved its flexibility and porosity. Moreover, chit/glu/HA scaffold revealed significantly higher water uptake capability (52.6% after 24h of soaking) compared to the chit/HA (30.7%) and thus can serve as a very good drug delivery carrier. Chit/glu/HA scaffold was also more favourable to osteoblast survival (near 100% viability after 24-h culture), proliferation, and spreading compared to the chit/HA (63% viability). The chit/glu/HA possesses better biomedical potential than chit/HA scaffold. Nevertheless, poor mechanical properties of the chit/glu/HA limit its application to non-load bearing implantation area. PMID:26478384

  5. Radionuclide bone imaging

    SciTech Connect

    Bassett, L.W.; Gold, R.H.; Webber, M.M.

    1981-12-01

    Radionuclide bone imaging of the skeleton, now well established as the most important diagnostic procedure in detecting bone metastases, is also a reliable method for the evaluation of the progression or regression of metastatic bone disease. The article concentrates on the technetium-99m agents and the value of these agents in the widespread application of low-dose radioisotope scanning in such bone diseases as metastasis, osteomyelitis, trauma, osteonecrosis, and other abnormal skeletal conditions.

  6. Microbial siderophores and their potential applications: a review.

    PubMed

    Saha, Maumita; Sarkar, Subhasis; Sarkar, Biplab; Sharma, Bipin Kumar; Bhattacharjee, Surajit; Tribedi, Prosun

    2016-03-01

    Siderophores are small organic molecules produced by microorganisms under iron-limiting conditions which enhance the uptake of iron to the microorganisms. In environment, the ferric form of iron is insoluble and inaccessible at physiological pH (7.35-7.40). Under this condition, microorganisms synthesize siderophores which have high affinity for ferric iron. These ferric iron-siderophore complexes are then transported to cytosol. In cytosol, the ferric iron gets reduced into ferrous iron and becomes accessible to microorganism. In recent times, siderophores have drawn much attention due to its potential roles in different fields. Siderophores have application in microbial ecology to enhance the growth of several unculturable microorganisms and can alter the microbial communities. In the field of agriculture, different types of siderophores promote the growth of several plant species and increase their yield by enhancing the Fe uptake to plants. Siderophores acts as a potential biocontrol agent against harmful phyto-pathogens and holds the ability to substitute hazardous pesticides. Heavy-metal-contaminated samples can be detoxified by applying siderophores, which explicate its role in bioremediation. Siderophores can detect the iron content in different environments, exhibiting its role as a biosensor. In the medical field, siderophore uses the "Trojan horse strategy" to form complexes with antibiotics and helps in the selective delivery of antibiotics to the antibiotic-resistant bacteria. Certain iron overload diseases for example sickle cell anemia can be treated with the help of siderophores. Other medical applications of siderophores include antimalarial activity, removal of transuranic elements from the body, and anticancer activity. The aim of this review is to discuss the important roles and applications of siderophores in different sectors including ecology, agriculture, bioremediation, biosensor, and medicine. PMID:25758420

  7. Metabolic processes of Methanococcus maripaludis and potential applications.

    PubMed

    Goyal, Nishu; Zhou, Zhi; Karimi, Iftekhar A

    2016-01-01

    Methanococcus maripaludis is a rapidly growing, fully sequenced, genetically tractable model organism among hydrogenotrophic methanogens. It has the ability to convert CO2 and H2 into a useful cleaner energy fuel (CH4). In fact, this conversion enhances in the presence of free nitrogen as the sole nitrogen source due to prolonged cell growth. Given the global importance of GHG emissions and climate change, diazotrophy can be attractive for carbon capture and utilization applications from appropriately treated flue gases, where surplus hydrogen is available from renewable electricity sources. In addition, M. maripaludis can be engineered to produce other useful products such as terpenoids, hydrogen, methanol, etc. M. maripaludis with its unique abilities has the potential to be a workhorse like Escherichia coli and S. cerevisiae for fundamental and experimental biotechnology studies. More than 100 experimental studies have explored different specific aspects of the biochemistry and genetics of CO2 and N2 fixation by M. maripaludis. Its genome-scale metabolic model (iMM518) also exists to study genetic perturbations and complex biological interactions. However, a comprehensive review describing its cell structure, metabolic processes, and methanogenesis is still lacking in the literature. This review fills this crucial gap. Specifically, it integrates distributed information from the literature to provide a complete and detailed view for metabolic processes such as acetyl-CoA synthesis, pyruvate synthesis, glycolysis/gluconeogenesis, reductive tricarboxylic acid (RTCA) cycle, non-oxidative pentose phosphate pathway (NOPPP), nitrogen metabolism, amino acid metabolism, and nucleotide biosynthesis. It discusses energy production via methanogenesis and its relation to metabolism. Furthermore, it reviews taxonomy, cell structure, culture/storage conditions, molecular biology tools, genome-scale models, and potential industrial and environmental applications. Through the

  8. Potential Applications of Carbohydrases Immobilization in the Food Industry

    PubMed Central

    Contesini, Fabiano Jares; de Alencar Figueira, Joelise; Kawaguti, Haroldo Yukio; de Barros Fernandes, Pedro Carlos; de Oliveira Carvalho, Patrícia; Nascimento, Maria da Graça; Sato, Hélia Harumi

    2013-01-01

    Carbohydrases find a wide application in industrial processes and products, mainly in the food industry. With these enzymes, it is possible to obtain different types of sugar syrups (viz. glucose, fructose and inverted sugar syrups), prebiotics (viz. galactooligossacharides and fructooligossacharides) and isomaltulose, which is an interesting sweetener substitute for sucrose to improve the sensory properties of juices and wines and to reduce lactose in milk. The most important carbohydrases to accomplish these goals are of microbial origin and include amylases (α-amylases and glucoamylases), invertases, inulinases, galactosidases, glucosidases, fructosyltransferases, pectinases and glucosyltransferases. Yet, for all these processes to be cost-effective for industrial application, a very efficient, simple and cheap immobilization technique is required. Immobilization techniques can involve adsorption, entrapment or covalent bonding of the enzyme into an insoluble support, or carrier-free methods, usually based on the formation of cross-linked enzyme aggregates (CLEAs). They include a broad variety of supports, such as magnetic materials, gums, gels, synthetic polymers and ionic resins. All these techniques present advantages and disadvantages and several parameters must be considered. In this work, the most recent and important studies on the immobilization of carbohydrases with potential application in the food industry are reviewed. PMID:23344046

  9. Flame Retardant Applications in Camping Tents and Potential Exposure.

    PubMed

    Keller, Alexander S; Raju, Nikhilesh P; Webster, Thomas F; Stapleton, Heather M

    2014-02-11

    Concern has mounted over health effects caused by exposure to flame retardant additives used in consumer products. Significant research efforts have focused particularly on exposure to polybrominated diphenyl ethers (PBDEs) used in furniture and electronic applications. However, little attention has focused on applications in textiles, particularly textiles meeting a flammability standard known as CPAI-84. In this study, we investigated flame retardant applications in camping tents that met CPAI-84 standards by analyzing 11 samples of tent fabrics for chemical flame retardant additives. Furthermore, we investigated potential exposure by collecting paired samples of tent wipes and hand wipes from 27 individuals after tent setup. Of the 11 fabric samples analyzed, 10 contained flame retardant additives, which included tris(1,3-dichloroisopropyl) phosphate (TDCPP), decabromodiphenyl ether (BDE-209), triphenyl phosphate, and tetrabromobisphenol-A. Flame retardant concentrations were discovered to be as high as 37.5 mg/g (3.8% by weight) in the tent fabric samples, and TDCPP and BDE-209 were the most frequently detected in these samples. We also observed a significant association between TDCPP levels in tent wipes and those in paired hand wipes, suggesting that human contact with the tent fabric material leads to the transfer of the flame retardant to the skin surface and human exposure. These results suggest that direct contact with flame retardant-treated textiles may be a source of exposure. Future studies will be needed to better characterize exposure, including via inhalation and dermal sorption from air. PMID:24804279

  10. Potential applications of carbohydrases immobilization in the food industry.

    PubMed

    Contesini, Fabiano Jares; de Alencar Figueira, Joelise; Kawaguti, Haroldo Yukio; de Barros Fernandes, Pedro Carlos; de Oliveira Carvalho, Patrícia; da Graça Nascimento, Maria; Sato, Hélia Harumi

    2013-01-01

    Carbohydrases find a wide application in industrial processes and products, mainly in the food industry. With these enzymes, it is possible to obtain different types of sugar syrups (viz. glucose, fructose and inverted sugar syrups), prebiotics (viz. galactooligossacharides and fructooligossacharides) and isomaltulose, which is an interesting sweetener substitute for sucrose to improve the sensory properties of juices and wines and to reduce lactose in milk. The most important carbohydrases to accomplish these goals are of microbial origin and include amylases (α-amylases and glucoamylases), invertases, inulinases, galactosidases, glucosidases, fructosyltransferases, pectinases and glucosyltransferases. Yet, for all these processes to be cost-effective for industrial application, a very efficient, simple and cheap immobilization technique is required. Immobilization techniques can involve adsorption, entrapment or covalent bonding of the enzyme into an insoluble support, or carrier-free methods, usually based on the formation of cross-linked enzyme aggregates (CLEAs). They include a broad variety of supports, such as magnetic materials, gums, gels, synthetic polymers and ionic resins. All these techniques present advantages and disadvantages and several parameters must be considered. In this work, the most recent and important studies on the immobilization of carbohydrases with potential application in the food industry are reviewed. PMID:23344046

  11. Flame Retardant Applications in Camping Tents and Potential Exposure

    PubMed Central

    2015-01-01

    Concern has mounted over health effects caused by exposure to flame retardant additives used in consumer products. Significant research efforts have focused particularly on exposure to polybrominated diphenyl ethers (PBDEs) used in furniture and electronic applications. However, little attention has focused on applications in textiles, particularly textiles meeting a flammability standard known as CPAI-84. In this study, we investigated flame retardant applications in camping tents that met CPAI-84 standards by analyzing 11 samples of tent fabrics for chemical flame retardant additives. Furthermore, we investigated potential exposure by collecting paired samples of tent wipes and hand wipes from 27 individuals after tent setup. Of the 11 fabric samples analyzed, 10 contained flame retardant additives, which included tris(1,3-dichloroisopropyl) phosphate (TDCPP), decabromodiphenyl ether (BDE-209), triphenyl phosphate, and tetrabromobisphenol-A. Flame retardant concentrations were discovered to be as high as 37.5 mg/g (3.8% by weight) in the tent fabric samples, and TDCPP and BDE-209 were the most frequently detected in these samples. We also observed a significant association between TDCPP levels in tent wipes and those in paired hand wipes, suggesting that human contact with the tent fabric material leads to the transfer of the flame retardant to the skin surface and human exposure. These results suggest that direct contact with flame retardant-treated textiles may be a source of exposure. Future studies will be needed to better characterize exposure, including via inhalation and dermal sorption from air. PMID:24804279

  12. A potential new diagnostic tool to aid DNA analysis from heat compromised bone using colorimetry: A preliminary study.

    PubMed

    Fredericks, Jamie D; Ringrose, Trevor J; Dicken, Anthony; Williams, Anna; Bennett, Phil

    2015-03-01

    Extracting viable DNA from many forensic sample types can be very challenging, as environmental conditions may be far from optimal with regard to DNA preservation. Consequently, skeletal tissue can often be an invaluable source of DNA. The bone matrix provides a hardened material that encapsulates DNA, acting as a barrier to environmental insults that would otherwise be detrimental to its integrity. However, like all forensic samples, DNA in bone can still become degraded in extreme conditions, such as intense heat. Extracting DNA from bone can be laborious and time-consuming. Thus, a lot of time and money can be wasted processing samples that do not ultimately yield viable DNA. We describe the use of colorimetry as a novel diagnostic tool that can assist DNA analysis from heat-treated bone. This study focuses on characterizing changes in the material and physical properties of heated bone, and their correlation with digitally measured color variation. The results demonstrate that the color of bone, which serves as an indicator of the chemical processes that have occurred, can be correlated with the success or failure of subsequent DNA amplification. PMID:25753998

  13. Evanescent field: A potential light-tool for theranostics application

    NASA Astrophysics Data System (ADS)

    Polley, Nabarun; Singh, Soumendra; Giri, Anupam; Pal, Samir Kumar

    2014-03-01

    A noninvasive or minimally invasive optical approach for theranostics, which would reinforce diagnosis, treatment, and preferably guidance simultaneously, is considered to be major challenge in biomedical instrument design. In the present work, we have developed an evanescent field-based fiber optic strategy for the potential theranostics application in hyperbilirubinemia, an increased concentration of bilirubin in the blood and is a potential cause of permanent brain damage or even death in newborn babies. Potential problem of bilirubin deposition on the hydroxylated fiber surface at physiological pH (7.4), that masks the sensing efficacy and extraction of information of the pigment level, has also been addressed. Removal of bilirubin in a blood-phantom (hemoglobin and human serum albumin) solution from an enhanced level of 77 μM/l (human jaundice >50 μM/l) to ˜30 μM/l (normal level ˜25 μM/l in human) using our strategy has been successfully demonstrated. In a model experiment using chromatography paper as a mimic of biological membrane, we have shown efficient degradation of the bilirubin under continuous monitoring for guidance of immediate/future course of action.

  14. Molecular potential energy surfaces for interstellar chemistry and fusion applications

    NASA Astrophysics Data System (ADS)

    Braams, Bastiaan J.; Huang, Xinchuan; Jin, Zhong; Xie, Zhen; Zhang, Xiubin; Bowman, Joel M.; Sharma, Amit Raj; Scheider, Ralf

    2006-04-01

    In the Born-Oppenheimer approximation the electronic Schr"odinger equation is solved given the nuclear positions as parameters, and this defines the potential energy surface. We have used computational invariant theory and the MAGMA computer algebra system as an aid to develop representations for the potential energy and dipole moment surfaces that are fully invariant under permutations of like nuclei, extending an approach that for 3-body and 4-body systems has a long history, e.g. [J. N. Murrell et al. Molecular Potential Energy Functions, Wiley, 1984]. A many-body (cluster) expansion is used to describe reaction complexes. The methods have been applied in an almost routine way for systems of up to 7 nuclei, including several molecules that are of interest for interstellar chemistry and for the issue of hydrocarbon breakdown in fusion edge plasma: H5^+, CH5, CH5^+, C2H3^+, and their fragments, with C2H5^+ on the way. The mathematical and computional methods and the hydrocarbon applications will be presented.

  15. Cancer therapy using bone-seeking isotopes

    NASA Astrophysics Data System (ADS)

    Lewington, V. J.

    1996-10-01

    Bone pain is a common symptom in disseminated malignancy and may be difficult to manage effectively. Radiation is of proven benefit for pain palliation and there is growing interest in the therapeutic potential of bone-seeking radiopharmaceuticals. Clinical data relating to the use of phosphorus-32, strontium-89, samarium-153 EDTMP, rhenium-186 HEDP and tin-117m DTPA are reviewed in the context of the pathophysiology of metastatic bone pain. Possible mechanisms of action of palliative radiotherapy and, in particular, the theoretical role of early response genes are discussed. The application of Monte Carlo simulation to targeted radiotherapy for bone metastases may provide the basis for a clearer understanding of the microdosimetry and radiobiology of bone pain palliation and for reliable prediction of clinical response and toxicity.

  16. Appropriate use of bone densitometry

    SciTech Connect

    Genant, H.K.; Block, J.E.; Steiger, P.; Glueer, C.C.; Ettinger, B.; Harris, S.T.

    1989-03-01

    The authors discuss current capabilities of three common bone densitometry techniques--single photon absorptiometry, dual photon absorptiometry, and quantitative computed tomography--and potential capabilities of new innovations of each of these techniques. They believe that use of bone densitometry is valid in the following four clinical applications and recommend its usage to (a) assess patients with metabolic diseases known to affect the skeleton, (b) assess perimenopausal women for initiation of estrogen replacement therapy, (c) establish a diagnosis of osteoporosis or assess its severity in the context of general clinical care, and (d) monitor the efficacy of treatment interventions or the natural course of disease.

  17. Potential applications of biphosphonates in dental surgical implants.

    PubMed

    Berardi, D; Carlesi, T; Rossi, F; Calderini, M; Volpi, R; Perfetti, G

    2007-01-01

    Biphosphonates are largely used for their unquestionable properties of inhibiting bone resorption by osteoclasts in the treatment of various osteometabolic illnesses such as osteoporosis, multiple myeloma, tumors which metastasize to the bone and malignant hypercalcemia. In this literature review the physico-chemical properties, biologic activities and the mechanisms of action of biphosphonates are described. The use of these drugs is discussed, analyzing the quantity of results which have emerged through in vitro and in vivo experiments on animal models. In this study the efficiency of these drugs is demonstrated in contrasting the osteolitic processes of the alveolar bone, in promoting the neoformation and in bettering the quality of bone implants. However, it is important to draw attention to a worrying correlation which has emerged during the last 3-4 years, between osteonecrosis of the jaw (ONJ) and the systemic administration of aminobiphosphonates. This collateral effect did not emerge following the use of non-aminobiphosphonates. The aim of this review is to identify the guidelines for the use of biphosphonates in oral implant surgery. PMID:17880759

  18. Comparative analysis of neural differentiation potential in human mesenchymal stem cells derived from chorion and adult bone marrow.

    PubMed

    Ziadlou, Reihane; Shahhoseini, Maryam; Safari, Fatemeh; Sayahpour, Forugh-Azam; Nemati, Shiva; Eslaminejad, Mohamadreza Baghaban

    2015-11-01

    The finding of a reliable and abundant source of stem cells for the replacement of missing neurons in nervous system diseases requires extensive characterization of neural-differentiation-associated markers in stem cells from various sources. Chorion-derived stem cells from the human placenta have recently been described as an abundant, ethically acceptable, and easily accessible source of cells that are not limited in the same way as bone marrow (BM) mesenchymal stem cells (MSCs). We have isolated and cultured chorion MSCs (C-MSCs) and compared their proliferative capacity, multipotency, and neural differentiation ability with BM-MSCs. C-MSCs showed a higher proliferative capacity compared with BM-MSCs. The expression and histone modification of Nestin, as a marker for neural stem/progenitor cells, was evaluated quantitatively between the two groups. The Nestin expression level in C-MSCs was significantly higher than that in BM-MSCs. Notably, modifications of lys9, lys4, and lys27 of histone H3 agreed with the remarkable higher expression of Nestin in C-MSCs than in BM-MSCs. Furthermore, after neural differentiation of MSCs upon retinoic acid induction, both immunocytochemical and flow cytometry analyses demonstrated that the expression of neural marker genes was significantly higher in neural-induced C-MSCs compared with BM-MSCs. Mature neuron marker genes were also expressed at a significantly higher level in C-MSCs than in BM-MSCs. Thus, C-MSCs have a greater potential than BM-MSCs for differentiation to neural cell lineages and can be regarded as a promising source of stem cells for the cell therapy of neurological disorders. PMID:26022335

  19. Cross-Talk Between Human Tenocytes and Bone Marrow Stromal Cells Potentiates Extracellular Matrix Remodeling In Vitro

    PubMed Central

    Ekwueme, Emmanuel C.; Shah, Jay V.; Mohiuddin, Mahir; Ghebes, Corina A.; Crispim, João F.; Saris, Daniël B.F.; Fernandes, Hugo A.M.; Freeman, Joseph W.

    2016-01-01

    Tendon and ligament (T/L) pathologies account for a significant portion of musculoskeletal injuries and disorders. Tissue engineering has emerged as a promising solution in the regeneration of both tissues. Specifically, the use of multipotent human mesenchymal stromal cells (hMSC) has shown great promise to serve as both a suitable cell source for tenogenic regeneration and a source of trophic factors to induce tenogenesis. Using four donor sets, we investigated the bidirectional paracrine tenogenic response between human hamstring tenocytes (hHT) and bone marrow-derived hMSC. Cell metabolic assays showed that only one hHT donor experienced sustained notable increases in cell metabolic activity during co-culture. Histological staining confirmed that co-culture induced elevated collagen protein levels in both cell types at varying time-points in two of four donor sets assessed. Gene expression analysis using qPCR showed the varied up-regulation of anabolic and catabolic markers involved in extracellular matrix maintenance for hMSC and hHT. Furthermore, analysis of hMSC/hHT co-culture secretome using a reporter cell line for TGF-β, a potent inducer of tenogenesis, revealed a trend of higher TGF-β bioactivity in hMSC secretome compared to hHT. Finally, hHT cytoskeletal immunostaining confirmed that both cell types released soluble factors capable of inducing favorable tenogenic morphology, comparable to control levels of soluble TGF-β1. These results suggest a potential for TGF-β-mediated signaling mechanism that is involved during the paracrine interplay between the two cell types that is reminiscent of T/L matrix remodeling/ turnover. These findings have significant implications in the clinical use of hMSC for common T/L pathologies. PMID:26308651

  20. Bioreactor-Based Online Recovery of Human Progenitor Cells with Uncompromised Regenerative Potential: A Bone Tissue Engineering Perspective

    PubMed Central

    Sonnaert, Maarten; Luyten, Frank P.; Papantoniou, Ioannis

    2015-01-01

    The use of a 3D perfusion culture environment for stem cell expansion has been shown to be beneficial for maintenance of the original cell functionality but due to several system inherent characteristics such as the presence of extracellular matrix, the continued development and implementation of 3D perfusion bioreactor technologies is hampered. Therefore, this study developed a methodology for harvesting a progenitor cell population from a 3D open porous culture surface after expansion in a perfusion bioreactor and performed a functional characterization of the expanded cells. An initial screening showed collagenase to be the most interesting reagent to release the cells from the 3D culture surface as it resulted in high yields without compromising cell viability. Subsequently a Design of Experiment approach was used to obtain optimized 3D harvest conditions by assessing the interplay of flow rate, collagenase concentration and incubation time on the harvest efficiency, viability and single cell fraction. Cells that were recovered with the optimized harvest protocol, by perfusing a 880 U/ml collagenase solution for 7 hours at a flow rate of 4 ml/min, were thereafter functionally analyzed for their characteristics as expanded progenitor cell population. As both the in vitro tri-lineage differentiation capacity and the in vivo bone forming potential were maintained after 3D perfusion bioreactor expansion we concluded that the developed seeding, culture and harvest processes did not significantly compromise the viability and potency of the cells and can contribute to the future development of integrated bioprocesses for stem cell expansion. PMID:26313143

  1. Investigating calcium polyphosphate addition to a conventional calcium phosphate cement for bone-interfacing applications

    NASA Astrophysics Data System (ADS)

    Krausher, Jennifer Lynn

    Calcium phosphate cements (CPCs) are of great interest in bone regeneration applications because of their biocompatibility and osteoconductivity, and as delivery vehicles for therapeutics; however, delivery applications have been limited by adverse interactions between therapeutics and the cement setting reaction. Amorphous calcium polyphosphate (CPP) yields a biodegradable material with a demonstrated drug delivery capacity following appropriate processing. The incorporation of drug-loaded CPP into a CPC is under consideration as a method of minimizing adverse interactions and extending drug release. This thesis represents the first investigation into the effects of CPP addition on the properties, setting and antibiotic release profile of a conventional apatitic calcium phosphate cement. As-made, gelled and vancomycin-loaded CPP particulate were added to the powder component of a conventional dicalcium phosphate/tetracalcium phosphate CPC. The setting behaviour, set properties and microstructure of the resulting CPP-CPCs were evaluated with setting time testing (Gilmore needle method), pH testing, mechanical testing, SEM imaging, XRD and FTIR analysis. In vitro degradation and elution behaviour were evaluated by monitoring calcium release (atomic absorbance spectroscopy), mechanical strength and vancomycin release (UV-visual spectrophotometry). CPP addition was found to increase the setting time, reduce the mechanical strength and inhibit the conversion of the CPC starting powders to the set apatitic phase. The most likely mechanism for the observed effect of CPP addition was the adsorption of polyphosphate chains on the particle surfaces, which would inhibit the dissolution of the starting powders and the conversion of apatite precursor phases to apatite, leading to reduced mechanical properties. The detrimental effects of CPP were reduced by limiting the CPP fraction to less than a few weight per cent and increasing the size of the CPP particulate. CPP

  2. Comparative Investigation of Human Amniotic Epithelial Cells and Mesenchymal Stem Cells for Application in Bone Tissue Engineering

    PubMed Central

    Si, Jiawen; Dai, Jiewen; Zhang, Jianjun; Liu, Sha; Gu, Jing; Shi, Jun; Shen, Steve G. F.; Guo, Lihe

    2015-01-01

    Emerging evidence suggests amniotic epithelial cells (AECs) as a promising source of progenitor cells in regenerative medicine and bone tissue engineering. However, investigations comparing the regenerative properties of AECs with other sources of stem cells are particularly needed before the feasibility of AECs in bone tissue engineering can be determined. This study aimed to compare human amniotic epithelial cells (hAECs), human bone marrow mesenchymal stem cells (hBMSCs), and human amniotic fluid derived mesenchymal stem cells (hAFMSCs) in terms of their morphology, proliferation, immunophenotype profile, and osteogenic capacity in vitro and in vivo. Not only greatly distinguished by cell morphology and proliferation, hAECs, hAFMSCs, and hBMSCs exhibited remarkably different signature regarding immunophenotypical profile. Microarray analysis revealed a different expression profile of genes involved in ossification along the three cell sources, highlighting the impact of different anatomical origin and molecular response to osteogenic induction on the final tissue-forming potential. Furthermore, our data indicated a potential role of FOXC2 in early osteogenic commitment. PMID:25834575

  3. An RNA-seq Protocol to Identify mRNA Expression Changes in Mouse Diaphyseal Bone: Applications in Mice with Bone Property Altering Lrp5 Mutations

    PubMed Central

    Ayturk, Ugur M.; Jacobsen, Christina M.; Christodoulou, Danos C.; Gorham, Joshua; Seidman, Jonathan G.; Seidman, Christine E.; Robling, Alexander G.; Warman, Matthew L.

    2013-01-01

    Loss-of-function and certain missense mutations in the Wnt co-receptor LRP5 significantly decrease or increase bone mass, respectively. These human skeletal phenotypes have been recapitulated in mice harboring Lrp5 knockout and knockin mutations. We hypothesized that measuring mRNA expression in diaphyseal bone from mice with Lrp5 wild-type (Lrp5+/+), knockout (Lrp5−/−), and high bone mass (HBM)-causing (Lrp5p.A214V/+) alleles could identify genes and pathways that regulate or are regulated by LRP5 activity. We performed RNA-seq on pairs of tibial diaphyseal bones from four 16-week-old mice with each of the aforementioned genotypes. We then evaluated different methods for controlling for contaminating non-skeletal tissue (i.e., blood, bone marrow, and skeletal muscle) in our data. These methods included pre-digestion of diaphyseal bone with collagenase and separate transcriptional profiling of blood, skeletal muscle and bone marrow. We found that collagenase digestion reduced contamination, but also altered gene expression in the remaining cells. In contrast, in silico filtering of the diaphyseal bone RNA-seq data for highly expressed blood, skeletal muscle, and bone marrow transcripts significantly increased the correlation between RNA-seq data from an animal’s right and left tibiae and from animals with the same Lrp5 genotype. We conclude that reliable and reproducible RNA-seq data can be obtained from mouse diaphyseal bone and that lack of LRP5 has a more pronounced effect on gene expression than the HBM-causing LRP5 missense mutation. We identified 84 differentially expressed protein-coding transcripts between LRP5 “sufficient” (i.e., Lrp5+/+ and Lrp5p.A214V/+) and “insufficient” (Lrp5−/−) diaphyseal bone, and far fewer differentially expressed genes between Lrp5p.A214V/+ and Lrp5+/+ diaphyseal bone. PMID:23553928

  4. RBC micromotors carrying multiple cargos towards potential theranostic applications

    NASA Astrophysics Data System (ADS)

    Wu, Zhiguang; Esteban-Fernández de Ávila, Berta; Martín, Aída; Christianson, Caleb; Gao, Weiwei; Thamphiwatana, Soracha Kun; Escarpa, Alberto; He, Qiang; Zhang, Liangfang; Wang, Joseph

    2015-08-01

    Red blood cell (RBC)-based micromotors containing both therapeutic and diagnostic modalities are described as a means for potential theranostic applications. In this natural RBC-based multicargo-loaded micromotor system, quantum dots (QDs), anti-cancer drug doxorubicin (DOX), and magnetic nanoparticles (MNPs), were co-encapsulated into RBC micromotors. The fluorescent emission of both QDs and DOX provides direct visualization of their loading inside the RBC motors at two distinct wavelengths. The presence of MNPs within the RBCs allows for efficient magnetic guidance under ultrasound propulsion along with providing the potential for magnetic resonance imaging. The simultaneous encapsulation of the imaging nanoparticles and therapeutic payloads within the same RBC micromotor has a minimal effect upon its propulsion behavior. The ability of the RBC micromotors to transport imaging and therapeutic agents at high speed and spatial precision through a complex microchannel network is also demonstrated. Such ability to load and transport diagnostic imaging agents and therapeutic drugs within a single cell-based motor, in addition to a lower toxicity observed once the drug is encapsulated within the multicargo RBC motor, opens the door to the development of theranostic micromotors that may simultaneously treat and monitor diseases.Red blood cell (RBC)-based micromotors containing both therapeutic and diagnostic modalities are described as a means for potential theranostic applications. In this natural RBC-based multicargo-loaded micromotor system, quantum dots (QDs), anti-cancer drug doxorubicin (DOX), and magnetic nanoparticles (MNPs), were co-encapsulated into RBC micromotors. The fluorescent emission of both QDs and DOX provides direct visualization of their loading inside the RBC motors at two distinct wavelengths. The presence of MNPs within the RBCs allows for efficient magnetic guidance under ultrasound propulsion along with providing the potential for magnetic

  5. Applications of Anabolic Vitamin D Analogs as Countermeasures to Bone Loss

    NASA Technical Reports Server (NTRS)

    Karin, Norman J.

    1998-01-01

    The experiments in Round 2 were designed to extend the results of our efforts in Round 1 which led us to hypothesize that the seco-steroid, 1,25-dihydroxyvitamin D3[1,25(OH)2D3], acts in synergy with parathyroid hormone (PTH) to regulate bone calcium homeostasis. Our work centered on one particular target of 1,25(OH)2D3 action, the voltage-sensitive calcium channels (VSCC's), which are activated acutely by this steroid within milliseconds of exposure . A second area of research focused on the effects of mechanical strain on VSCC expression in bone. These experiments were performed in collaboration with Dr. Steven Goldstein (Univ. Michigan), who generously provided RNA extracted from dog bones that had been exposed to mechanical strain in vivo. Our results suggest that mechanical loading elevated VSCC expression in the long bones from 3 of the 6 animals tested. A second line of experimentation, carried out in collaboration with Dr. Randall Duncan, a NASA-funded investigator in Indianapolis, centered on RT-PCR analysis of effects of mechanical strain on Ca2(+) channel expression in cultured bone cells. Compared to unstrained controls, the expression of vitamin-D-sensidve Ca2(+) channels is elevated 3- to 5-fold over a 24 hr period.

  6. Image registration of proximal femur with substantial bone changes: application in 3D visualization of bone loss of astronauts after long-duration spaceflight

    NASA Astrophysics Data System (ADS)

    Li, Wenjun; Sode, Miki; Saeed, Isra; Lang, Thomas

    2006-03-01

    We recently studied bone loss in crewmembers making 4 to 6 months flights on the International Space Station. We employed Quantitative Computed Tomography (QCT) technology (Lang et. al., J Bone Miner Res. 2004; v. 19, p. 1006), which made measurements of both cortical and trabecular bone loss that could not be obtained by using 2-dimensional dual x-ray absorptiometry (DXA) imaging technology. To further investigate the bone loss after spaceflight, we have developed image registration technologies to align serial scans so that bone changes can be directly visualized in a subregional level, which can provide more detailed information for understanding bone physiology during long-term spaceflight. To achieve effective and robust registration when large bone changes exist, we have developed technical adaptations to standard registration methods. Our automated image registration is mutual-information based. We have applied an automatically adaptive binning method in calculating the mutual information. After the pre- and post-flight scans are geometrically aligned, the interior bone changes can be clearly visualized. Image registration can also be applied to Finite Element Modeling (FEM) to compare bone strength change, where consistent loading conditions must be applied to serial scans.

  7. Direct Lentiviral-Cyclooxygenase 2 Application to the Tendon-Bone Interface Promotes Osteointegration and Enhances Return of the Pull-Out Tensile Strength of the Tendon Graft in a Rat Model of Biceps Tenodesis

    PubMed Central

    Wergedal, Jon E.; Stiffel, Virginia; Lau, Kin-Hing William

    2014-01-01

    This study sought to determine if direct application of the lentiviral (LV)-cyclooxygenase 2 (COX2) vector to the tendon-bone interface would promote osteointegration of the tendon graft in a rat model of biceps tenodesis. The LV-COX2 gene transfer strategy was chosen for investigation because a similar COX2 gene transfer strategy promoted bony bridging of the fracture gap during bone repair, which involves similar histologic transitions that occur in osteointegration. Briefly, a 1.14-mm diameter tunnel was drilled in the mid-groove of the humerus of adult Fischer 344 rats. The LV-COX2 or βgal control vector was applied directly into the bone tunnel and onto the end of the tendon graft, which was then pulled into the bone tunnel. A poly-L-lactide pin was press-fitted into the tunnel as interference fixation. Animals were sacrificed at 3, 5, or 8 weeks for histology analysis of osteointegration. The LV-COX2 gene transfer strategy enhanced neo-chondrogenesis at the tendon-bone interface but with only marginal effect on de novo bone formation. The tendon-bone interface of the LV-COX2-treated tenodesis showed the well-defined tendon-to-fibrocartilage-to-bone histologic transitions that are indicative of osteointegration of the tendon graft. The LV-COX2 in vivo gene transfer strategy also significantly enhanced angiogenesis at the tendon-bone interface. To determine if the increased osteointegration was translated into an improved pull-out mechanical strength property, the pull-out tensile strength of the LV-COX2-treated tendon grafts was determined with a pull-out mechanical testing assay. The LV-COX2 strategy yielded a significant improvement in the return of the pull-out strength of the tendon graft after 8 weeks. In conclusion, the COX2-based in vivo gene transfer strategy enhanced angiogenesis, osteointegration and improved return of the pull-out strength of the tendon graft. Thus, this strategy has great potential to be developed into an effective therapy to

  8. Direct lentiviral-cyclooxygenase 2 application to the tendon-bone interface promotes osteointegration and enhances return of the pull-out tensile strength of the tendon graft in a rat model of biceps tenodesis.

    PubMed

    Rundle, Charles H; Chen, Shin-Tai; Coen, Michael J; Wergedal, Jon E; Stiffel, Virginia; Lau, Kin-Hing William

    2014-01-01

    This study sought to determine if direct application of the lentiviral (LV)-cyclooxygenase 2 (COX2) vector to the tendon-bone interface would promote osteointegration of the tendon graft in a rat model of biceps tenodesis. The LV-COX2 gene transfer strategy was chosen for investigation because a similar COX2 gene transfer strategy promoted bony bridging of the fracture gap during bone repair, which involves similar histologic transitions that occur in osteointegration. Briefly, a 1.14-mm diameter tunnel was drilled in the mid-groove of the humerus of adult Fischer 344 rats. The LV-COX2 or βgal control vector was applied directly into the bone tunnel and onto the end of the tendon graft, which was then pulled into the bone tunnel. A poly-L-lactide pin was press-fitted into the tunnel as interference fixation. Animals were sacrificed at 3, 5, or 8 weeks for histology analysis of osteointegration. The LV-COX2 gene transfer strategy enhanced neo-chondrogenesis at the tendon-bone interface but with only marginal effect on de novo bone formation. The tendon-bone interface of the LV-COX2-treated tenodesis showed the well-defined tendon-to-fibrocartilage-to-bone histologic transitions that are indicative of osteointegration of the tendon graft. The LV-COX2 in vivo gene transfer strategy also significantly enhanced angiogenesis at the tendon-bone interface. To determine if the increased osteointegration was translated into an improved pull-out mechanical strength property, the pull-out tensile strength of the LV-COX2-treated tendon grafts was determined with a pull-out mechanical testing assay. The LV-COX2 strategy yielded a significant improvement in the return of the pull-out strength of the tendon graft after 8 weeks. In conclusion, the COX2-based in vivo gene transfer strategy enhanced angiogenesis, osteointegration and improved return of the pull-out strength of the tendon graft. Thus, this strategy has great potential to be developed into an effective therapy to

  9. Quantitative computed tomography of bone.

    PubMed

    Rüegsegger, P; Stebler, B; Dambacher, M

    1982-07-01

    Computed tomography (CT) is well accepted as an imaging procedure, but comparatively little effort has been made to utilize the potential capability of CT to quantify tissue densities and composition. There are two reasons for this. First, precision and accuracy of quantification are limited by nonlinear effects. These effects are nonlocal and are object and scanner dependent. Second, intraindividual and interindividual variations of tissue compositions are considerable. Single energy measurements require restrictive assumptions on tissue compositions. The diagnosis and treatment monitoring of osteopenic bone diseases with low-dose CT is given as an example of a successful application of quantitative CT. With a special-purpose CT system and an analytic procedure for the quantification of bone at peripheral measuring sites, longitudinal examinations were performed. Low-dose quantitative CT permitted quantification, on an individual basis, of the bone loss of immobilization osteoporosis on a week-by-week basis. Changes due to postmenopausal osteoporosis are less drastic, and so measurement at intervals of months is adequate. In women after menopause, 3-month intervals were used in evaluating the natural course of osteoporosis and in quantifying the effects of sodium fluoride treatment on trabecular bone. Low-dose quantitative CT has proved to be a sensitive and highly reproducible procedure for the noninvasive evaluation of bone loss or bone accretion. During a disease or therapy, each patient can be evaluated individually. PMID:7121079

  10. Equine mesenchymal stem cells from bone marrow, adipose tissue and umbilical cord: immunophenotypic characterization and differentiation potential

    PubMed Central

    2014-01-01

    Introduction Studies with mesenchymal stem cells (MSCs) are increasing due to their immunomodulatory, anti-inflammatory and tissue regenerative properties. However, there is still no agreement about the best source of equine MSCs for a bank for allogeneic therapy. The aim of this study was to evaluate the cell culture and immunophenotypic characteristics and differentiation potential of equine MSCs from bone marrow (BM-MSCs), adipose tissue (AT-MSCs) and umbilical cord (UC-MSCs) under identical in vitro conditions, to compare these sources for research or an allogeneic therapy cell bank. Methods The BM-MSCs, AT-MSCs and UC-MSCs were cultured and evaluated in vitro for their osteogenic, adipogenic and chondrogenic differentiation potential. Additionally, MSCs were assessed for CD105, CD44, CD34, CD90 and MHC-II markers by flow cytometry, and MHC-II was also assessed by immunocytochemistry. To interpret the flow cytometry results, statistical analysis was performed using ANOVA. Results The harvesting and culturing procedures of BM-MSCs, AT-MSCs and UC-MSCs were feasible, with an average cell growth until the third passage of 25 days for BM-MSCs, 15 days for AT-MSCs and 26 days for UC-MSCs. MSCs from all sources were able to differentiate into osteogenic (after 10 days for BM-MSCs and AT-MSCs and 15 days for UC-MSCs), adipogenic (after 8 days for BM-MSCs and AT-MSCs and 15 days for UC-MSCs) and chondrogenic (after 21 days for BM-MSCs, AT-MSCs and UC-MSCs) lineages. MSCs showed high expression of CD105, CD44 and CD90 and low or negative expression of CD34 and MHC-II. The MHC-II was not detected by immunocytochemistry techniques in any of the MSCs studied. Conclusions The BM, AT and UC are feasible sources for harvesting equine MSCs, and their immunophenotypic and multipotency characteristics attained minimal criteria for defining MSCs. Due to the low expression of MHC-II by MSCs, all of the sources could be used in clinical trials involving allogeneic therapy

  11. Recombinant Protein Production of Earthworm Lumbrokinase for Potential Antithrombotic Application

    PubMed Central

    Wang, Kevin Yueju; Wang, Nan; Liu, Dehu

    2013-01-01

    Earthworms have been used as a traditional medicine in China, Japan, and other Far East countries for thousands of years. Oral administration of dry earthworm powder is considered as a potent and effective supplement for supporting healthy blood circulation. Lumbrokinases are a group of enzymes that were isolated and purified from different species of earthworms. These enzymes are recognized as fibrinolytic agents that can be used to treat various conditions associated with thrombosis. Many lumbrokinase (LK) genes have been cloned and characterized. Advances in genetic technology have provided the ability to produce recombinant LK and have made it feasible to purify a single lumbrokinase enzyme for potential antithrombotic application. In this review, we focus on expression systems that can be used for lumbrokinase production. In particular, the advantages of using a transgenic plant system to produce edible lumbrokinase are described. PMID:24416067

  12. Self-assembling peptides and their potential applications in biomedicine.

    PubMed

    Rymer, Sarah-Jane; Tendler, Saul J B; Bosquillon, Cynthia; Washington, Clive; Roberts, Clive J

    2011-08-01

    For many years, peptides have been known to self-assemble to form nano- and micro-scale structures. Their nature of assembly and assembled morphology has since been investigated as this area of research has important implications for the development of both drug delivery and tissue regeneration. In this article, we explore the process of peptide self-assembly in vivo, and experiments that exploit the structures formed. Particular focus is directed towards diphenylalanine, the simplest self-assembling peptide, which generally forms tube-like structures on assembly. In addition, different peptides that may assemble into a range of other morphologies are highlighted and potential applications in regenerative medicine and drug delivery discussed. PMID:22826867

  13. Glycolipid biosurfactants: Potential related biomedical and biotechnological applications.

    PubMed

    Inès, Mnif; Dhouha, Ghribi

    2015-10-30

    Glycolipids, consisting of a carbohydrate moiety linked to fatty acids, are microbial surface active compounds produced by various microorganisms. They are characterized by highly structural diversity and have the ability to decrease the surface and interfacial tension at the surface and interface respectively. Rhamnolipids, trehalolipids, mannosylerythritol-lipids and cellobiose lipids are among the most popular glycolipids. Moreover, their ability to form pores and destabilize biological membrane permits their use in biomedicine as antibacterial, antifungal and hemolytic agents. Their antiviral and antitumor effects enable their use in pharmaceutic as therapeutic agents. Also, glycolipids can inhibit the bioadhesion of pathogenic bacteria enabling their use as anti-adhesive agents and for disruption of biofilm formation and can be used in cosmetic industry. Moreover, they have great potential application in industry as detergents, wetting agents and for flotation. Furthermore, glycolipids can act at the surface and can modulate enzyme activity permitting the enhancement or the inhibition of the activity of certain enzymes. PMID:26359535

  14. Molecular Imaging with MRI: Potential Application in Pancreatic Cancer

    PubMed Central

    Chen, Chen; Wu, Chang Qiang; Chen, Tian Wu; Tang, Meng Yue; Zhang, Xiao Ming

    2015-01-01

    Despite the variety of approaches that have been improved to achieve a good understanding of pancreatic cancer (PC), the prognosis of PC remains poor, and the survival rates are dismal. The lack of early detection and effective interventions is the main reason. Therefore, considerable ongoing efforts aimed at identifying early PC are currently being pursued using a variety of methods. In recent years, the development of molecular imaging has made the specific targeting of PC in the early stage possible. Molecular imaging seeks to directly visualize, characterize, and measure biological processes at the molecular and cellular levels. Among different imaging technologies, the magnetic resonance (MR) molecular imaging has potential in this regard because it facilitates noninvasive, target-specific imaging of PC. This topic is reviewed in terms of the contrast agents for MR molecular imaging, the biomarkers related to PC, targeted molecular probes for MRI, and the application of MRI in the diagnosis of PC. PMID:26579537

  15. Relativistic optimized effective potential method-application to alkali metals.

    PubMed

    Ködderitzsch, D; Ebert, H; Akai, H; Engel, E

    2009-02-11

    We present a relativistic formulation of the optimized effective potential method (ROEP) and its implementation within the Korringa-Kohn-Rostoker multiple scattering formalism. The scheme is an all-electron approach, treating core and band states formally on the same footing. We use exact exchange (EXX) as an approximation to the exchange correlation functional. Numerical four-component wavefunctions for the description of core and valence electrons and the corresponding ingredients of the ROEP integral equation are employed. The exact exchange expression for the valence states is reformulated in terms of the electronic Green's function that in turn is evaluated by making use of multiple scattering formalism. We present and discuss the application of the formalism to non-magnetic alkali metals. PMID:21715911

  16. Linear polarization difference imaging and its potential applications.

    PubMed

    Nan, Zeng; Xiaoyu, Jiang; Qiang, Gao; Yonghong, He; Hui, Ma

    2009-12-10

    We demonstrate a novel linear polarization imaging technique and its potential application in dermatology. This technique records a series of images corresponding to different combinations of illumination and detection polarization and calculates intensity differences between orthogonal detection polarizations pixel by pixel. Fitting the polarization difference data to an analytical expression of the incident and detection polarization angles results in two new parameters, G and (phi3)/2. It is shown that G is strongly correlated to the order of alignment of the fibrous structure in the sample, and (phi3)/2 represents the angle of orientation of the fibers. Preliminary clinical testing implies that this method may be applied for medical diagnosis of skin diseases. PMID:20011013

  17. Mesenchymal stem cells associated with porous chitosan-gelatin scaffold: a potential strategy for alveolar bone regeneration.

    PubMed

    Miranda, Suzana C C C; Silva, Gerluza A B; Mendes, Renato M; Abreu, Fernando Antônio M; Caliari, Marcelo V; Alves, José B; Goes, Alfredo M

    2012-10-01

    Tissue engineering has emerged as a novel treatment for replacement of lost bone tissue. This study evaluated the effects of a chitosan-gelatin scaffold seeded with bone marrow mesenchymal stem cells (BMMSCs) in the healing process of tooth sockets in rats. BMMSCs isolated from transgenic rats expressing enhanced green fluorescent protein (eGFP) were expanded and seeded on a chitosan-gelatin scaffold. These constructs were cultured for three days and characterized by scanning electronic microscopy (SEM) and energy dispersion spectroscopy (EDS). Receptor rats received the implant in the left sockets, after upper first-molar extraction. Right alveoli served as control. Animals were sacrificed at days 5, 21, and 35 post-graft for examination. Morphometry demonstrated increased bone mineralization after 21 and 35 days in transplanted sockets. Migration, differentiation, and fate of eGFP-labeled BMMSCs were monitored by immunohistochemistry. Tartrate-resistant acid phosphatase staining (TRAP) was carried out at 21 days, to identify the involvement of osteoclastic cells in the scaffold resorption. The biomaterial was resorbed by TRAP-negative giant cells in a typical foreign body reaction. Immunohistochemical findings showed that BMMSCs contributed to bone, epithelial, and vascular repair. Together, results indicate that BMMSCs loaded in the chitosan-gelatin scaffold is a strategy for tissue development in bone engineering. PMID:22623117

  18. Qualitative application based on IR spectroscopy for bone sample quality control in radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Gianfrate, G.; D'Elia, M.; Quarta, G.; Giotta, L.; Valli, L.; Calcagnile, L.

    2007-06-01

    Bone samples suffer from contamination and deterioration, depending on their conservation state and previous restoration and consolidation processes. The sample preparation laboratory of the CEDAD (Center for Dating and Diagnostics) of the University of Lecce is developing a quality control protocol for bone samples based on Fourier transform infrared (FTIR) spectroscopy to identify the presence of collagen in bone samples and to assess its quality. FTIR measurements were carried out on collagen extracted from many ancient samples dated at CEDAD. Efforts to shift the FTIR quality control test from the filtration step to a check-in treatment are proceeding to optimize the time for preparation and to reduce the overall turnaround time. A standard fast demineralization treatment was set up and applied to a variety of ancient samples of different origin and age.

  19. Numerical damage models using a structural approach: application in bones and ligaments

    NASA Astrophysics Data System (ADS)

    Arnoux, P. J.; Bonnoit, J.; Chabrand, P.; Jean, M.; Pithioux, M.

    2002-01-01

    The purpose of the present study was to apply knowledge of structural properties to perform numerical simulations with models of bones and knee ligaments exposed to dynamic tensile loading leading to tissue damage. Compact bones and knee ligaments exhibit the same geometrical pattern in their different levels of structural hierarchy from the tropocollagen molecule to the fibre. Nevertheless, their mechanical behaviours differ considerably at the fibril level. These differences are due to the contribution of the joints in the microfibril-fibril-fibre assembly and to the mechanical properties of the structural components. Two finite element models of the fibrous bone and ligament structure were used to describe damage in terms of elastoplastic laws or joint decohesion processes.

  20. Histopathological evaluation of potential impact of β-tricalcium phosphate (HA+ β-TCP) granules on healing of segmental femur bone defect.

    PubMed

    Eftekhari, H; Farahpour, M R; Rabiee, S M

    2015-01-01

    Histopathological evaluation of β-tricalcium phosphate (HA+ β-TCP) granules demonstrated that it has properties to heal segmental femur bone defect in rat. In this study, 27 male white rats were examined. Rats were divided into tree groups. Surgical procedures were done after IP administration of ketamine 5 % and xylazine HCL 2 %. Then an approximately 5-mm long, 3-mm deep and 2-mm wide bone defect was created in the femur of one of the hind limbs using a No. 0.14 round bur. After inducing the surgical wound, all rats were colored and randomly divided into three experimental groups of nine animals each: Group 1 received medical pure β-tricalcium phosphate granules, group 2 received hydroxyapatite and third group was a control group with no treatment. Histopathological evaluation was performed on days 15, 30 and 45 after surgery. On day 45 after surgery, the quantity of newly formed lamellar bone in the healing site in β-TCP group was better than onward compared to HA and control groups. In conclusion, β-tri calcium phosphate (β-TCP) granules exhibited a reproducible bone-healing potential (Fig. 10, Ref. 28). PMID:25666959

  1. Evaluation of transport conditions for autologous bone marrow-derived mesenchymal stromal cells for therapeutic application in horses.

    PubMed

    Espina, Miguel; Jülke, Henriette; Brehm, Walter; Ribitsch, Iris; Winter, Karsten; Delling, Uta

    2016-01-01

    Background. Mesenchymal stromal cells (MSCs) are increasingly used for clinical applications in equine patients. For MSC isolation and expansion, a laboratory step is mandatory, after which the cells are sent back to the attending veterinarian. Preserving the biological properties of MSCs during this transport is paramount. The goal of the study was to compare transport-related parameters (transport container, media, temperature, time, cell concentration) that potentially influence characteristics of culture expanded equine MSCs. Methods. The study was arranged in three parts comparing (I) five different transport containers (cryotube, two types of plastic syringes, glass syringe, CellSeal), (II) seven different transport media, four temperatures (4 °C vs. room temperature; -20 °C vs. -80 °C), four time frames (24 h vs. 48 h; 48 h vs. 72 h), and (III) three MSC concentrations (5 × 10(6), 10 × 10(6), 20 × 10(6) MSC/ml). Cell viability (Trypan Blue exclusion; percent and total number viable cell), proliferation and trilineage differentiation capacity were assessed for each test condition. Further, the recovered volume of the suspension was determined in part I. Each condition was evaluated using samples of six horses (n = 6) and differentiation protocols were performed in duplicates. Results. In part I of the study, no significant differences in any of the parameters were found when comparing transport containers at room temperature. The glass syringe was selected for all subsequent evaluations (highest recoverable volume of cell suspension and cell viability). In part II, media, temperatures, or time frames had also no significant influence on cell viability, likely due to the large number of comparisons and small sample size. Highest cell viability was observed using autologous bone marrow supernatant as transport medium, and "transport" at 4 °C for 24 h (70.6% vs. control group 75.3%); this was not significant. Contrary, viability was unacceptably low (<40

  2. Evaluation of transport conditions for autologous bone marrow-derived mesenchymal stromal cells for therapeutic application in horses

    PubMed Central

    Espina, Miguel; Jülke, Henriette; Brehm, Walter; Ribitsch, Iris; Winter, Karsten

    2016-01-01

    Background. Mesenchymal stromal cells (MSCs) are increasingly used for clinical applications in equine patients. For MSC isolation and expansion, a laboratory step is mandatory, after which the cells are sent back to the attending veterinarian. Preserving the biological properties of MSCs during this transport is paramount. The goal of the study was to compare transport-related parameters (transport container, media, temperature, time, cell concentration) that potentially influence characteristics of culture expanded equine MSCs. Methods. The study was arranged in three parts comparing (I) five different transport containers (cryotube, two types of plastic syringes, glass syringe, CellSeal), (II) seven different transport media, four temperatures (4 °C vs. room temperature; −20 °C vs. −80 °C), four time frames (24 h vs. 48 h; 48 h vs. 72 h), and (III) three MSC concentrations (5 × 106, 10 × 106, 20 × 106 MSC/ml). Cell viability (Trypan Blue exclusion; percent and total number viable cell), proliferation and trilineage differentiation capacity were assessed for each test condition. Further, the recovered volume of the suspension was determined in part I. Each condition was evaluated using samples of six horses (n = 6) and differentiation protocols were performed in duplicates. Results. In part I of the study, no significant differences in any of the parameters were found when comparing transport containers at room temperature. The glass syringe was selected for all subsequent evaluations (highest recoverable volume of cell suspension and cell viability). In part II, media, temperatures, or time frames had also no significant influence on cell viability, likely due to the large number of comparisons and small sample size. Highest cell viability was observed using autologous bone marrow supernatant as transport medium, and “transport” at 4 °C for 24 h (70.6% vs. control group 75.3%); this was not significant. Contrary, viability was unacceptably low

  3. [Potential applications of marijuana and cannabinoids in medicine].

    PubMed

    Zdrojewicz, Zygmunt; Pypno, Damian; Cabała, Krzysztof; Bugaj, Bartosz; Waracki, Mateusz

    2014-10-01

    Cannabinoids, psychoactive substances present in cannabis, have been known to mankind for hundreds of years. Apart from 9-tetrahydrocannabinol (THC) substances found in the cannabis herb with the highest toxicological value are cannabidiol (CBD) and cannabinol (CBN). The discovery of CB1 and CB2 receptors, located in various tissues (ranging from the brain to peripheral tissues), has defined the potential objective of these new chemical substances' effects. Many studies on the application of cannabinoids in the treatment of various diseases such as diabetes, neoplasms, inflammatory diseases, neurological conditions, pain and vomitting were conducted. Drugs containing e.g. THC appear on the pharmaceutical market. Substances affecting cannabinoid receptors may show beneficial effects, but they may also cause the risk of side effects related mainly to the inhibition of central nervous system. The purpose of this dissertation is the analysis, whether the substances responsible for the effects of marijuana, can find application in medicine. Original articles and reviews were used to summarize the results of studies connected to the topic. PMID:25518584

  4. Potential applications of extracorporeal photopheresis in liver transplantation.

    PubMed

    Urbani, L; Mazzoni, A; Colombatto, P; Biancofiore, G; Bindi, L; Tascini, C; Menichetti, F; Brunetto, M; Scatena, F; Filipponi, F

    2008-05-01

    Extracorporeal photopheresis (ECP) is an immunomodulatory therapy performed through a temporary peripheral venous access with documented efficacy in heart and renal transplantation. We originally reported that ECP represented a valuable alternative to treat graft rejection in selected liver transplant (OLT) recipients. We have investigated potential applications of ECP for prophylaxis of allograft rejection. The first field explored was the use of ECP for delayed introduction of calcineurin inhibitors (CNI) among high-risk OLT recipients seeking to avoid CNI toxicity. In 42 consecutive patients that we assigned to prophylaxis with ECP, we were able to delay CNI introduction after postoperative day 8 in one-third of them. The second field was the use of ECP for prophylaxis of acute cellular rejection among ABO-incompatible OLT recipients. In our experience, none of 11 patients treated with ECP developed a cell-mediated rejection. The third field was ECP application in hepatitis C virus-positive patients seeking to reduce the immunosuppressive burden and improve sustainability and efficacy of preemptive antiviral treatment with interferon and ribavirin. Among 78 consecutive patients, we were able to start preemptive antiviral treatment in 69.2% of them at a median time from OLT of 14 days (range = 7 to 130 days). Thirty-six (66.7%) patients completed the treatment course with an end of treatment virological response of 50.0% and a sustained virological response of 38.9%. These preliminary results await validation in larger prospective studies with longer follow-up periods. PMID:18555142

  5. Ultrashort pulse laser interactions with cortical bone tissue for applications in orthopaedic surgery

    NASA Astrophysics Data System (ADS)

    Ashforth, Simon A.; Simpson, M. C.; Bodley, Owen; Oosterbeek, Reece

    2015-03-01

    Using a femtosecond pulsed laser system (pulse width = 100fs, repetition rate = 1kHz, λ = 800nm), ablation threshold studies of freshly culled bovine and ovine cortical bone samples were identified using the diameter regression technique. Using the D2 technique, the ablation threshold was found to lie within a range of 0.83 - 0.96 Jcm-2 and 0.89 - 0.95 Jcm-2 for ovine and bovine cortical bone respectively indicating that laser ablation of bone is irrespective of target species. The relationship between cortical bone tissue removal and the number of applied pulses was explored. By altering the laser spot translation rate, we varied the number of pulses at each point along scribed linear cuts. Optical Coherence Tomography (OCT) and PDMS casting indicates that cut depth is linearly dependent on the number of pulses applied to the tissue, irrespective of donor species. For single pulse ablation of ovine and bovine cortical bone, we determined that the ablation rates were 0.41 - 0.75 μm per pulse and 0.28 - 0.90 μm per pulse when pulses of fluences in the range 0.52 - 2.63 Jcm-2 were applied to ovine and bovine cortical bone tissue, respectively. Structural analysis of the ablation features using environmental scanning electron microscopy and optical microscopy were utilized to assess the ablation features and identify signs of damage to surrounding tissue. We observed no structural indications of thermal shockwave cracking, molten debris deposition or charring of the tissue whilst leaving hydroxyapatite crystal structure intact.

  6. RBC micromotors carrying multiple cargos towards potential theranostic applications.

    PubMed

    Wu, Zhiguang; Esteban-Fernández de Ávila, Berta; Martín, Aída; Christianson, Caleb; Gao, Weiwei; Thamphiwatana, Soracha Kun; Escarpa, Alberto; He, Qiang; Zhang, Liangfang; Wang, Joseph

    2015-08-28

    Red blood cell (RBC)-based micromotors containing both therapeutic and diagnostic modalities are described as a means for potential theranostic applications. In this natural RBC-based multicargo-loaded micromotor system, quantum dots (QDs), anti-cancer drug doxorubicin (DOX), and magnetic nanoparticles (MNPs), were co-encapsulated into RBC micromotors. The fluorescent emission of both QDs and DOX provides direct visualization of their loading inside the RBC motors at two distinct wavelengths. The presence of MNPs within the RBCs allows for efficient magnetic guidance under ultrasound propulsion along with providing the potential for magnetic resonance imaging. The simultaneous encapsulation of the imaging nanoparticles and therapeutic payloads within the same RBC micromotor has a minimal effect upon its propulsion behavior. The ability of the RBC micromotors to transport imaging and therapeutic agents at high speed and spatial precision through a complex microchannel network is also demonstrated. Such ability to load and transport diagnostic imaging agents and therapeutic drugs within a single cell-based motor, in addition to a lower toxicity observed once the drug is encapsulated within the multicargo RBC motor, opens the door to the development of theranostic micromotors that may simultaneously treat and monitor diseases. PMID:26214151

  7. Upgrading of sea by-products: potential nutraceutical applications.

    PubMed

    Cudennec, B; Caradec, T; Catiau, L; Ravallec, R

    2012-01-01

    Since many years, numerous kinds of processes based on enzymatic hydrolysis at various pH, involving added plant or bacterial enzymes after inactivation by heating of endogenous enzymes present in the raw material or, alternatively, based on the action of endogenous enzymes, have contributed to the degradation of marine by-product proteins in order to produce fractions exerting biological activities. Peptides obtained by enzymatic hydrolysis of fish proteins exhibit not only nutritional but also biological properties of dietary uses, or even therapeutic potential. In this review, we have focused on the different enzymatic processes able to generate bioactive peptides from marine by-products and exerting high potential in nutraceutical applications to fight against important public health issues like obesity, stress, hypertension, and migraine. Beyond the nutraceutical and pharmaceutical aspects, this way of valorization is also included in the necessary development of by-product fishing industries for economic and ecological reasons in the worldwide context of marine resources depletion. PMID:22361207

  8. Computational mitral valve evaluation and potential clinical applications.

    PubMed

    Chandran, Krishnan B; Kim, Hyunggun

    2015-06-01

    The mitral valve (MV) apparatus consists of the two asymmetric leaflets, the saddle-shaped annulus, the chordae tendineae, and the papillary muscles. MV function over the cardiac cycle involves complex interaction between the MV apparatus components for efficient blood circulation. Common diseases of the MV include valvular stenosis, regurgitation, and prolapse. MV repair is the most popular and most reliable surgical treatment for early MV pathology. One of the unsolved problems in MV repair is to predict the optimal repair strategy for each patient. Although experimental studies have provided valuable information to improve repair techniques, computational simulations are increasingly playing an important role in understanding the complex MV dynamics, particularly with the availability of patient-specific real-time imaging modalities. This work presents a review of computational simulation studies of MV function employing finite element structural analysis and fluid-structure interaction approach reported in the literature to date. More recent studies towards potential applications of computational simulation approaches in the assessment of valvular repair techniques and potential pre-surgical planning of repair strategies are also discussed. It is anticipated that further advancements in computational techniques combined with the next generations of clinical imaging modalities will enable physiologically more realistic simulations. Such advancement in imaging and computation will allow for patient-specific, disease-specific, and case-specific MV evaluation and virtual prediction of MV repair. PMID:25134487

  9. AC electrokinetic manipulation of selenium nanoparticles for potential nanosensor applications

    SciTech Connect

    Mahmoodi, Seyed Reza; Bayati, Marzieh; Hosseinirad, Somayeh; Foroumadi, Alireza; Gilani, Kambiz; Rezayat, Seyed Mahdi

    2013-03-15

    Highlights: ► Se nanoparticles were synthesized using a reverse-microemulsion process. ► AC osmotic fluid flow repulses the particles from electrode edges. ► Dielectrophoretic force attracts the particles to electrode edges. ► Dielectrophoresis electrode showed non-ohmic behavior. ► The device can potentially be used as a nanosensor. - Abstract: We report the AC electrokinetic behavior of selenium (Se) nanoparticles for electrical characterization and possible application as micro/nano devices. selenium Se nanoparticles were successfully synthesized using a reverse-microemulsion process and investigated structurally using X-ray diffraction and transmission electron microscope. Interdigitated castellated ITO and non-castellated platinum electrodes were employed for manipulation of suspended materials in the fluid. Using ITO electrodes at low frequency limits resulted in deposition of Se particles on electrode surface. When Se particles exposed to platinum electrodes in the 10 Hz–1 kHz range and V {sub p−p}> 8, AC osmotic fluid flow repulses the particles from electrode edges. However, in 10 kHz–10 MHz range and V {sub p−p}> 5, dielectrophoretic force attracts the particles to electrode edges. As the Se particle concentration increased, the trapped Se particles were aligned along the electric field line and bridged the electrode gap. The device was characterized and can potentially be useful in making micro/nano electronic devices.

  10. Bacteriocins synthesized by Bacillus thuringiensis: generalities and potential applications

    PubMed Central

    Salazar-Marroquín, Elma Laura; Galán-Wong, Luis J.; Moreno-Medina, Víctor Ricardo; Reyes-López, Miguel Ángel; Pereyra-Alférez, Benito

    2016-01-01

    The members of the Bacillus thuringiensis group, commonly known as Bt, produce a huge number of metabolites, which show biocidal and antagonistic activity. B. thuringiensis is widely known for synthesizing Cry, Vip and Cyt proteins, active against insects and other parasporins with biocidal activity against certain types of cancerous cells. Nevertheless, B. thuringiensis also synthesizes compounds with antimicrobial activity, especially bacteriocins. Some B. thuringiensis bacteriocins resemble lantibiotics and other small linear peptides (class IIa) from the lactic acid bacteria bacteriocins classification system. Although many bacteriocins produced by Bt have been reported, there is no proper classification for them. In this work, we have grouped these based on molecular weight and functionality. Bacteriocins are small peptides synthesized by bacteria, presenting inhibitory activity against Gram-positive and Gram-negative bacteria and to a lesser extent against fungi. These molecules represent a good study model in the search for microbial control alternatives. Lactic acid bacteria produces a huge number of these types of molecules with great potential. Nonetheless, members of the Bacillus, cereus group, especially B. thuringiensis, emerge as an attractive alternative for obtaining bacteriocins showing novel activities. This review describes the potential applications of B. thuringiensis bacteriocins in the control of foodborne pathogens, environment and medical area. PMID:27340340

  11. Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. I. Preparation and in vitro degradation.

    PubMed

    Fu, Qiang; Rahaman, Mohamed N; Fu, Hailuo; Liu, Xin

    2010-10-01

    Bioactive glass scaffolds with a microstructure similar to that of dry human trabecular bone but with three different compositions were evaluated for potential applications in bone repair. The preparation of the scaffolds and the effect of the glass composition on the degradation and conversion of the scaffolds to a hydroxyapatite (HA)-type material in a simulated body fluid (SBF) are reported here (Part I). The in vitro response of osteogenic cells to the scaffolds and the in vivo evaluation of the scaffolds in a rat subcutaneous implantation model are described in Part II. Scaffolds (porosity = 78-82%; pore size = 100-500 microm) were prepared using a polymer foam replication technique. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. The conversion rate of the scaffolds to HA in the SBF increased markedly with the B2O3 content of the glass. Concurrently, the pH of the SBF also increased with the B2O3 content of the scaffolds. The compressive strengths of the as-prepared scaffolds (5-11 MPa) were in the upper range of values reported for trabecular bone, but they decreased markedly with immersion time in the SBF and with increasing B2O3 content of the glass. The results show that scaffolds with a wide range of bioactivity and degradation rate can be achieved by replacing varying amounts of SiO(2) in silicate bioactive glass with B2O3. PMID:20544804

  12. Design and application of chitosan/biphasic calcium phosphate porous scaffolds for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Sendemir-Urkmez, Aylin

    For the restoration of maxillofacial bone tissue, design of novel tissue engineering scaffolds capable of inducing bone remodeling through the delivery of mesenchymal stem cells (MSCs) and an angiogenic growth factor, directly at the site of the defect was investigated in order to replace autogenous cancellous bone grafts with synthetic materials. Porous, three dimensional scaffolds were fabricated by a freeze drying method. In culture media, biphasic calcium phosphate particles within chitosan produced a surface reprecipitate of a composition similar to natural apatite that led to a uniform distribution of cells and mineralized ECM through chemotaxis. Further, the reprecipitation regulated the differentiation pathway and phenotype commitment of stem cells by altering the initial cell attachment morphology and actin cytoskeleton organization. In order to induce neovascularization after implantation, constructs were designed to be loaded with gelatin microspheres that delivered basic fibroblast growth factor (bFGF), a potent angiogenic factor. In vitro proliferation tests performed on fibroblastic cells showed no detectible loss of bFGF activity when delivered through enzymatic degradation of gelatin. Laser scanning confocal microscopy was used to demonstrate that gelatin microspheres can be injected evenly into cell-scaffold constructs owing to the spongy characteristics of the scaffold. To examine the binding interactions of bFGF with surface bound gelatin, a label free biosensor system, Biomolecular INteraction Detection sensor (BIND) was used. Results confirm that the principal interaction that takes place between bFGF and gelatin is electrostatic. Cell loaded tissue engineered constructs were produced in vitro at clinically relevant sizes and implanted with and without bFGF into a porcine mandibular defect model. Tissue engineered constructs facilitated the healing of mandibular defects only if combined with delivery of bFGF via gelatin microspheres. b

  13. Novel and potential application of cryopreservation to plant genetic transformation.

    PubMed

    Wang, Biao; Zhang, Zhibo; Yin, Zhenfang; Feng, Chaohong; Wang, Qiaochun

    2012-01-01

    The world population now is 6.7 billion and is predicted to reach 9 billion by 2050. Such a rapid growing population has tremendously increased the challenge for food security. Obviously, it is impossible for traditional agriculture to ensure the food security, while plant biotechnology offers considerable potential to realize this goal. Over the last 15 years, great benefits have been brought to sustainable agriculture by commercial cultivation of genetically modified (GM) crops. Further development of new GM crops will with no doubt contribute to meeting the requirements for food by the increasing population. The present article provides updated comprehensive information on novel and potential application of cryopreservation to genetic transformation. The major progresses that have been achieved in this subject include (1), long-term storage of a large number of valuable plant genes, which offers a good potential for further development of novel cultivars by genetic transformation; (2), retention of regenerative capacity of embryogenic tissues and protoplasts, which ensures efficient plant regeneration system for genetic transformation; (3), improvement of transformation efficiency and plant regeneration of transformed cells; (4), long-term preservation of transgenic materials with stable expression of transgenes and productive ability of recombinant proteins, which allows transgenic materials to be stored in a safe manner before being analyzed and evaluated, and allows establishment of stable seed stocks for commercial production of homologous proteins. Data provided in this article clearly demonstrate that cryo-technique has an important role to play in the whole chain of genetic transformation. Further studies coupling cryotechnique and genetic transformation are expected to significantly improve development of new GM crops. PMID:22079800

  14. Adenosine and Bone Metabolism

    PubMed Central

    Mediero, Aránzazu; Cronstein, Bruce N.

    2013-01-01

    Bone is a dynamic organ that undergoes continuous remodeling whilst maintaining a balance between bone formation and resorption. Osteoblasts, which synthesize and mineralize new bone, and osteoclasts, the cells that resorb bone, act in concert to maintain bone homeostasis. In recent years, there has been increasing appreciation of purinergic regulation of bone metabolism. Adenosine, released locally, mediates its physiologic and pharmacologic actions via interactions with G-protein coupled receptors and recent work has indicated that these receptors are involved in the regulation of osteoclast differentiation and function, as well as osteoblast differentiation and bone formation. Moreover, adenosine receptors also regulate chondrocyte and cartilage homeostasis. These recent findings underscore the potential therapeutic importance of adenosine receptors in regulating bone physiology and pathology. PMID:23499155

  15. Nanomaterials and bone regeneration

    PubMed Central

    Gong, Tao; Xie, Jing; Liao, Jinfeng; Zhang, Tao; Lin, Shiyu; Lin, Yunfeng

    2015-01-01

    The worldwide incidence of bone disorders and conditions has been increasing. Bone is a nanomaterials composed of organic (mainly collagen) and inorganic (mainly nano-hydroxyapatite) components, with a hierarchical structure ranging from nanoscale to macroscale. In consideration of the serious limitation in traditional therapies, nanomaterials provide some new strategy in bone regeneration. Nanostructured scaffolds provide a closer structural support approximation to native bone architecture for the cells and regulate cell proliferation, differentiation, and migration, which results in the formation of functional tissues. In this article, we focused on reviewing the classification and design of nanostructured materials and nanocarrier materials for bone regeneration, their cell interaction properties, and their application in bone tissue engineering and regeneration. Furthermore, some new challenges about the future research on the application of nanomaterials for bone regeneration are described in the conclusion and perspectives part. PMID:26558141

  16. Application of the Skin and Bone Integrated Pylon (SBIP) with titanium oxide nanotubes and seeded with dermal fibroblasts

    PubMed Central

    Shevtsov, Maxim A.; Yudintceva, Natalia M.; Blinova, Miralda I.; Pinaev, Grigoriy P.; Galibin, Oleg V.; Potokin, Igor L.; Popat, Ketul C.; Pitkin, Mark R.

    2014-01-01

    Study Design The feasibility and safety of in bone implantation of the skin and bone integrated pylons (SBIP) with nanotubes was investigated in vitro and in vivo in the animal model. Background Direct Direct skeletal attachment of limb prostheses is associated with high rate of transcutaneous infection and loosening of the fixture in the medullary canal prompting for careful assessment of various means for enhancing the skin-device and bone-device interface. The SBIP system constitutes a technological platform for different modifications being evaluated previously. Objectives The current study assessed the combination of nano treatment SBIP with its pre seeding with dermal fibroblasts. We hypothesized that this combination will enhance cell interaction with SBIP compared to nano treatment and the fibroblast seeding when done separately. Methods TiO2 nanotubes were fabricated on the SBIP, and the fibroblasts taken from rabbit's skin were cultured on the pylons before implantation. Results The in vitro experiments demonstrated higher cellular density in the samples with a nanotubular surface than in the non modified pylons used as control. There were no postoperative complications in any of the animals during the 6 month observation period. Subsequent SEM of the pylon extracted from the rabbit's femur showed the stable contact between the pylon and soft tissues in comparison to control samples where the patchy fibrovascular ingrowth was detected. Conclusions The promising results prompt further investigation of the integrative properties of the nanotextured SBIP system seeded with dermal fibroblasts and its optimization for clinical application. PMID:25249382

  17. Ultrasound simulation in bone.

    PubMed

    Kaufman, Jonathan J; Luo, Gangming; Siffert, Robert S

    2008-01-01

    The manner in which ultrasound interacts with bone is of key interest in therapy and diagnosis alike. These may include applications directly to bone, as, for example, in treatment to accelerate the healing of bone fractures and in assessment of bone density in osteoporosis, or indirectly in diagnostic imaging of soft tissue with interest in assessing exposure levels to nearby bone. Because of the lack of analytic solutions to virtually every "practical problem" encountered clinically, ultrasound simulation has become a widely used technique for evaluating ultrasound interactions in bone. This paper provides an overview of the use of ultrasound simulation in bone. A brief description of the mathematical model used to characterize ultrasound propagation in bone is first provided. A number of simulation examples are then presented that explain how simulation may be utilized in a variety of practical configurations. The focus of this paper in terms of examples presented is on diagnostic applications in bone, and, in particular, for assessment of osteoporosis. However, the use of simulation in other areas of interest can easily be extrapolated from the examples presented. In conclusion, this paper describes the use of ultrasound simulation in bone and demonstrates the power of computational methods for ultrasound research in general and tissue and bone applications in particular. PMID:18599409

  18. Application of the elusieve process to the classification of meat and bone meal particles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Meat and bone meal (MBM), a product of the rendering industry, comprises a mixture of two particle types. The utility and value of MBM would increase if the two particle types could be separated economically. Past efforts at classification of MBM particles have achieved limited success. In the pr...

  19. Preparation and characterization of hydroxyapatite/sodium alginate biocomposites for bone implant application

    NASA Astrophysics Data System (ADS)

    Kanasan, Nanthini; Adzila, Sharifah; Suid, Mohd Syafiq; Gurubaran, P.

    2016-07-01

    In biomedical fields, synthetic scaffolds are being improved by using the ceramics, polymers and composites materials to avoid the limitations of allograft. Ceramic-polymer composites are appearing to be the most successful bone graft substitute in human body. The natural bones itself are well-known as composite of collagen and hydroxyapatite. In this research, precipitation method was used to synthesis hydroxyapatite (HA)/sodium alginate (SA) in various parameters. This paper describes the hydroxyapatite/sodium alginate biocomposite which suitable for use in bone defects or regeneration of bone through the characterizations which include FTIR, FESEM, EDS and DTA. In FTIR, the characteristi peaks of PO4-3 and OH- groups which corresponding to hydroxyapatite are existed in the mixing powders. The needle-size particle of hydroxyapatite/ alginate (HA/SA) are observed in FESEM in the range of 15.8nm-38.2nm.EDS confirmed the existence of HA/SA composition in the mixing powders. There is an endothermic peak which corresponds to the dehydration and the loss of physically adsorbed water molecules of the hydroxyapatite (HA)/sodium alginate (SA) powder which are described in DTA.

  20. Porous titanium with entangled structure filled with biodegradable magnesium for potential biomedical applications.

    PubMed

    Jiang, Guofeng; Wang, Cunlong; Li, Qiuyan; Dong, Jie; He, Guo

    2015-02-01

    A kind of Ti-Mg composite was prepared by infiltrating the biodegradable magnesium melt into the porous titanium (p-Ti) with entangled structure. The microstructure and the mechanical properties of the composites were investigated by using the metallographic technique and the compressive testing method. The novelty in the elastic property was discussed based on the experimental results and the referenced data. It was found that as the Ti volume fractions increased from 37.1% to 53.6%, the compressive plateau stress of the p-Ti/Mg composites increased from 175 MPa to 246 MPa, but the Young's modulus decreased from 47 GPa to 22 GPa. When the magnesium matrix was strengthened by adding 0.5 wt.% Zr, the plateau stress and the Young's modulus of the p-Ti/Mg(Zr) composites were reasonably enhanced. The stiffness of the p-Ti/Mg composites is comparable to that of the cortical bone, suggesting their considerable potentials for the load-bearing orthopedic applications. PMID:25492182

  1. Isolation, characterization and the multi-lineage differentiation potential of rabbit bone marrow-derived mesenchymal stem cells

    PubMed Central

    Tan, Sik-Loo; Ahmad, Tunku Sara; Selvaratnam, Lakshmi; Kamarul, Tunku

    2013-01-01

    Mesenchymal stem cells (MSCs) are recognized by their plastic adherent ability, fibroblastic-like appearance, expression of specific surface protein markers, and are defined by their ability to undergo multi-lineage differentiation. Although rabbit bone marrow-derived MSCs (rbMSCs) have been used extensively in previous studies especially in translational research, these cells have neither been defined morphologically and ultrastructurally, nor been compared with their counterparts in humans in their multi-lineage differentiation ability. A study was therefore conducted to define the morphology, surface marker proteins, ultrastructure and multi-lineage differentiation ability of rbMSCs. Herein, the primary rbMSC cultures of three adult New Zealand white rabbits (at least 4 months old) were used for three independent experiments. rbMSCs were isolated using the gradient-centrifugation method, an established technique for human MSCs (hMSCs) isolation. Cells were characterized by phase contrast microscopy observation, transmission electron microscopy analysis, reverse transcriptase-polymerase chain reaction (PCR) analysis, immunocytochemistry staining, flow cytometry, alamarBlue® assay, histological staining and quantitative (q)PCR analysis. The isolated plastic adherent cells were in fibroblastic spindle-shape and possessed eccentric, irregular-shaped nuclei as well as rich inner cytoplasmic zones similar to that of hMSCs. The rbMSCs expressed CD29, CD44, CD73, CD81, CD90 and CD166, but were negative (or dim positive) for CD34, CD45, CD117 and HLD-DR. Despite having similar morphology and phenotypic expression, rbMSCs possessed significantly larger cell size but had a lower proliferation rate as compared with hMSCs. Using established protocols to differentiate hMSCs, rbMSCs underwent osteogenic, adipogenic and chondrogenic differentiation. Interestingly, differentiated rbMSCs demonstrated higher levels of osteogenic (Runx2) and chondrogenic (Sox9) gene expressions

  2. Bone Diseases

    MedlinePlus

    ... also avoid smoking and drinking too much alcohol. Bone diseases can make bones easy to break. Different kinds ... Bones can also develop cancer and infections Other bone diseases, which are caused by poor nutrition, genetics, or ...

  3. Bone Grafts

    MedlinePlus

    ... repair and rebuild diseased bones in your hips, knees, spine, and sometimes other bones and joints. Grafts can also repair bone loss caused by some types of fractures or cancers. Once your body accepts the bone ...

  4. Effects of sterilization and storage on the properties of ALP-grafted biomaterials for prosthetic and bone tissue engineering applications.

    PubMed

    Ferraris, S; Pan, G; Cassinelli, C; Mazzucco, L; Vernè, E; Spriano, S

    2012-10-01

    Grafting of the biomaterial surfaces with biomolecules is nowadays a challenging research field for prosthetic and bone tissue engineering applications. On the other hand, very few research works investigate the effect of the sterilization processes on the properties of functionalized biomaterials. In this study, the effects of different sterilization techniques (e.g. gamma and electron beam irradiation, ethylene oxide) on the enzymatic activity of bioactive glasses and Ti6Al4V grafted with alkaline phosphatase (ALP) have been analyzed. Sterility maintenance and in vitro bioactivity of the sterilized surfaces have also been investigated. Finally the effect of packaging and storage conditions has been considered. PMID:22971978

  5. In Vitro Corrosion and Cytocompatibility Properties of Nano-Whisker Hydroxyapatite Coating on Magnesium Alloy for Bone Tissue Engineering Applications

    PubMed Central

    Yang, Huawei; Yan, Xueyu; Ling, Min; Xiong, Zuquan; Ou, Caiwen; Lu, Wei

    2015-01-01

    We report here the successful fabrication of nano-whisker hydroxyapatite (nHA) coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries. PMID:25789500

  6. Biodegradable poly(epsilon-caprolactone) nanowires for bone tissue engineering applications.

    PubMed

    Porter, Joshua R; Henson, Andrew; Popat, Ketul C

    2009-02-01

    Critical-sized defects in bone, whether caused by cancer tumor resection, trauma, or selective surgery have in many cases presented insurmountable challenges to the current gold-standard treatment for bone repair. The primary purpose of a tissue-engineered scaffold is to incite and promote the natural healing process of bone, which does not occur in critical-sized defects. In this work, a solvent-free template synthesis technique was utilized to fabricate uniform arrays of substrate-bound poly(epsilon-caprolactone) (PCL) nanowires. Biodegradation of PCL nanowire surfaces was characterized using scanning electron microscopy (SEM) and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. Rat bone marrow-derived mesenchymal stem cells (MSCs) were employed to assess short-term biocompatibility and long-term bioactivity of nanowire surfaces. Short-term cell studies indicated that PCL nanowire surfaces supported enhanced cell adhesion and viability compared with control surfaces. MSCs seeded on nanowire surfaces also displayed increased levels of alkaline phosphatase (ALP) after 1, 2, and 3 weeks in culture. Calcium-phosphate mineralization was substantially accelerated on nanowire surfaces compared to control surfaces as indicated through calcium staining, von Kossa staining, SEM, and electron dispersive spectroscopy (EDS). Increased levels of inter- and extracellular levels of osteocalcin and osteopontin were observed on nanowire surfaces using immunofluorescence techniques after 3 weeks of culture. Considering the simplicity of the presented fabrication technique, capacity for solvent-free encapsulation of bioactive molecules or particles, and enhanced MSC performance on nanowire surfaces, this work presents an excellent foundation for the development of 3-D scaffolds for bone tissue regeneration. PMID:19012962

  7. Sequential Application of Steady and Pulsatile Medium Perfusion Enhanced the Formation of Engineered Bone

    PubMed Central

    Correia, Cristina; Bhumiratana, Sarindr; Sousa, Rui A.; Reis, Rui L.

    2013-01-01

    In native bone, cells experience fluctuating shear forces that are induced by pulsatile interstitial flow associated with habitual loading. We hypothesized that the formation of engineered bone can be augmented by replicating such physiologic stimuli to osteogenic cells cultured in porous scaffolds using bioreactors with medium perfusion. To test this hypothesis, we investigated the effect of fluid flow regime on in vitro bone-like tissue development by human adipose stem cells (hASC) cultivated on porous three-dimensional silk fibroin scaffolds. To this end, we varied the sequential relative durations of steady flow (SF) and pulsatile flow (PF) of culture medium applied over a period of 5 weeks, and evaluated their effect on early stages of bone formation. Porous silk fibroin scaffolds (400–600 μm pore size) were seeded with hASC (30×106 cells/mL) and cultured in osteogenic medium under four distinct fluid flow regimes: (1) PF for 5 weeks; (2) SF for 1 week, PF for 4 weeks; (3) SF for 2 weeks, PF for 3 weeks; (4) SF for 5 weeks. The PF was applied in 12 h intervals, with the interstitial velocity fluctuating between 400 and 1200 μm/s at a 0.5 Hz frequency for 2 h, followed by 10 h of SF. In all groups, SF was applied at 400 μm/s. The best osteogenic outcomes were achieved for the sequence of 2 weeks of SF and 3 weeks of PF, as evidenced by gene expression (including the PGE2 mechanotransduction marker), construct compositions, histomorphologies, and biomechanical properties. We thus propose that osteogenesis in hASC and the subsequent early stage bone development involve a mechanism, which detects and responds to the level and duration of hydrodynamic shear forces. PMID:23259605

  8. SH3BP2 cherubism mutation potentiates TNF-α-induced osteoclastogenesis via NFATc1 and TNF-α-mediated inflammatory bone loss

    PubMed Central

    Mukai, Tomoyuki; Ishida, Shu; Ishikawa, Remi; Yoshitaka, Teruhito; Kittaka, Mizuho; Gallant, Richard; Lin, Yi-Ling; Rottapel, Robert; Brotto, Marco; Reichenberger, Ernst J.; Ueki, Yasuyoshi

    2014-01-01

    Cherubism (OMIM#118400) is a genetic disorder with excessive jawbone resorption caused by mutations in the signaling adaptor protein SH3BP2. Studies on the mouse model for cherubism carrying a P416R knock-in mutation have revealed that mutant SH3BP2 enhances TNF-α production and RANKL-induced osteoclast differentiation in myeloid cells. TNF-α is expressed in human cherubism lesions, which contain a large number of TRAP-positive multinucleated cells, and TNF-α plays a critical role in inflammatory bone destruction in homozygous cherubism mice (Sh3bp2KI/KI). The data suggest a pathophysiological relationship between mutant SH3BP2 and TNF-α-mediated bone loss by osteoclasts. Therefore, we investigated whether P416R mutant SH3BP2 is involved in TNF-α-mediated osteoclast formation and bone loss. Here, we show that bone marrow-derived M-CSF-dependent macrophages (BMMs) from the heterozygous cherubism mutant (Sh3bp2KI/+) mice are highly responsive to TNF-α and can differentiate into osteoclasts independently of RANKL in vitro by a mechanism that involves SYK and PLCγ2 phosphorylation, leading to increased nuclear translocation of NFATc1. The heterozygous cherubism mutation exacerbates bone loss with increased osteoclast formation in a mouse calvarial TNF-α injection model as well as in a human TNF-α transgenic mouse model (hTNFtg). SH3BP2 knockdown in RAW264.7 cells results in decreased TRAP-positive multinucleated cell formation. These findings suggest that the SH3BP2 cherubism mutation can cause jawbone destruction by promoting osteoclast formation in response to TNF-α expressed in cherubism lesions and that SH3BP2 is a key regulator for TNF-α-induced osteoclastogenesis. Inhibition of SH3BP2 expression in osteoclast progenitors could be a potential strategy for the treatment of bone loss in cherubism as well as in other inflammatory bone disorders. PMID:24916406

  9. Selective laser sintering fabrication of nano-hydroxyapatite/poly-ε-caprolactone scaffolds for bone tissue engineering applications.

    PubMed

    Xia, Yan; Zhou, Panyu; Cheng, Xiaosong; Xie, Yang; Liang, Chong; Li, Chao; Xu, Shuogui

    2013-01-01

    The regeneration of functional tissue in osseous defects is a formidable challenge in orthopedic surgery. In the present study, a novel biomimetic composite scaffold, here called nano-hydroxyapatite (HA)/poly-ε-caprolactone (PCL) was fabricated using a selective laser sintering technique. The macrostructure, morphology, and mechanical strength of the scaffolds were characterized. Scanning electronic microscopy (SEM) showed that the nano-HA/PCL scaffolds exhibited predesigned, well-ordered macropores and interconnected micropores. The scaffolds have a range of porosity from 78.54% to 70.31%, and a corresponding compressive strength of 1.38 MPa to 3.17 MPa. Human bone marrow stromal cells were seeded onto the nano-HA/PCL or PCL scaffolds and cultured for 28 days in vitro. As indicated by the level of cell attachment and proliferation, the nano-HA/PCL showed excellent biocompatibility, comparable to that of PCL scaffolds. The hydrophilicity, mineralization, alkaline phosphatase activity, and Alizarin Red S staining indicated that the nano-HA/PCL scaffolds are more bioactive than the PCL scaffolds in vitro. Measurements of recombinant human bone morphogenetic protein-2 (rhBMP-2) release kinetics showed that after nano-HA was added, the material increased the rate of rhBMP-2 release. To investigate the in vivo biocompatibility and osteogenesis of the composite scaffolds, both nano-HA/PCL scaffolds and PCL scaffolds were implanted in rabbit femur defects for 3, 6, and 9 weeks. The wounds were studied radiographically and histologically. The in vivo results showed that both nano-HA/PCL composite scaffolds and PCL scaffolds exhibited good biocompatibility. However, the nano-HA/PCL scaffolds enhanced the efficiency of new bone formation more than PCL scaffolds and fulfilled all the basic requirements of bone tissue engineering scaffolds. Thus, they show large potential for use in orthopedic and reconstructive surgery. PMID:24204147

  10. Selective laser sintering fabrication of nano-hydroxyapatite/poly-ε-caprolactone scaffolds for bone tissue engineering applications

    PubMed Central

    Xia, Yan; Zhou, Panyu; Cheng, Xiaosong; Xie, Yang; Liang, Chong; Li, Chao; Xu, Shuogui

    2013-01-01

    The regeneration of functional tissue in osseous defects is a formidable challenge in orthopedic surgery. In the present study, a novel biomimetic composite scaffold, here called nano-hydroxyapatite (HA)/poly-ε-caprolactone (PCL) was fabricated using a selective laser sintering technique. The macrostructure, morphology, and mechanical strength of the scaffolds were characterized. Scanning electronic microscopy (SEM) showed that the nano-HA/PCL scaffolds exhibited predesigned, well-ordered macropores and interconnected micropores. The scaffolds have a range of porosity from 78.54% to 70.31%, and a corresponding compressive strength of 1.38 MPa to 3.17 MPa. Human bone marrow stromal cells were seeded onto the nano-HA/PCL or PCL scaffolds and cultured for 28 days in vitro. As indicated by the level of cell attachment and proliferation, the nano-HA/PCL showed excellent biocompatibility, comparable to that of PCL scaffolds. The hydrophilicity, mineralization, alkaline phosphatase activity, and Alizarin Red S staining indicated that the nano-HA/PCL scaffolds are more bioactive than the PCL scaffolds in vitro. Measurements of recombinant human bone morphogenetic protein-2 (rhBMP-2) release kinetics showed that after nano-HA was added, the material increased the rate of rhBMP-2 release. To investigate the in vivo biocompatibility and osteogenesis of the composite scaffolds, both nano-HA/PCL scaffolds and PCL scaffolds were implanted in rabbit femur defects for 3, 6, and 9 weeks. The wounds were studied radiographically and histologically. The in vivo results showed that both nano-HA/PCL composite scaffolds and PCL scaffolds exhibited good biocompatibility. However, the nano-HA/PCL scaffolds enhanced the efficiency of new bone formation more than PCL scaffolds and fulfilled all the basic requirements of bone tissue engineering scaffolds. Thus, they show large potential for use in orthopedic and reconstructive surgery. PMID:24204147

  11. Pain Related Cortical Oscillations: Methodological Advances and Potential Applications

    PubMed Central

    Peng, Weiwei; Tang, Dandan

    2016-01-01

    Alongside the time-locked event-related potentials (ERPs), nociceptive somatosensory inputs can induce modulations of ongoing oscillations, appeared as event-related synchronization or desynchronization (ERS/ERD) in different frequency bands. These ERD/ERS activities are suggested to reflect various aspects of pain perception, including the representation, encoding, assessment, and integration of the nociceptive sensory inputs, as well as behavioral responses to pain, even the precise details of their roles remain unclear. Previous studies investigating the functional relevance of ERD/ERS activities in pain perception were normally done by assessing their latencies, frequencies, magnitudes, and scalp distributions, which would be then correlated with subjective pain perception or stimulus intensity. Nevertheless, these temporal, spectral, and spatial profiles of stimulus induced ERD/ERS could only partly reveal the dynamics of brain oscillatory activities. Indeed, additional parameters, including but not limited to, phase, neural generator, and cross frequency couplings, should be paid attention to comprehensively and systemically evaluate the dynamics of oscillatory activities associated with pain perception and behavior. This would be crucial in exploring the psychophysiological mechanisms of neural oscillation, and in understanding the neural functions of cortical oscillations involved in pain perception and behavior. Notably, some chronic pain (e.g., neurogenic pain and complex regional pain syndrome) patients are often associated with the occurrence of abnormal synchronized oscillatory brain activities, and selectively modulating cortical oscillatory activities has been showed to be a potential therapy strategy to relieve pain with the application of neurostimulation techniques, e.g., repeated transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS). Thus, the investigation of the oscillatory activities proceeding from

  12. Configuration and technology implications of potential nuclear hydrogen system applications.

    SciTech Connect

    Conzelmann, G.; Petri, M.; Forsberg, C.; Yildiz, B.; ORNL

    2005-11-05

    Nuclear technologies have important distinctions and potential advantages for large-scale generation of hydrogen for U.S. energy services. Nuclear hydrogen requires no imported fossil fuels, results in lower greenhouse-gas emissions and other pollutants, lends itself to large-scale production, and is sustainable. The technical uncertainties in nuclear hydrogen processes and the reactor technologies needed to enable these processes, as well waste, proliferation, and economic issues must be successfully addressed before nuclear energy can be a major contributor to the nation's energy future. In order to address technical issues in the time frame needed to provide optimized hydrogen production choices, the Nuclear Hydrogen Initiative (NHI) must examine a wide range of new technologies, make the best use of research funding, and make early decisions on which technology options to pursue. For these reasons, it is important that system integration studies be performed to help guide the decisions made in the NHI. In framing the scope of system integration analyses, there is a hierarchy of questions that should be addressed: What hydrogen markets will exist and what are their characteristics? Which markets are most consistent with nuclear hydrogen? What nuclear power and production process configurations are optimal? What requirements are placed on the nuclear hydrogen system? The intent of the NHI system studies is to gain a better understanding of nuclear power's potential role in a hydrogen economy and what hydrogen production technologies show the most promise. This work couples with system studies sponsored by DOE-EE and other agencies that provide a basis for evaluating and selecting future hydrogen production technologies. This assessment includes identifying commercial hydrogen applications and their requirements, comparing the characteristics of nuclear hydrogen systems to those market requirements, evaluating nuclear hydrogen configuration options within a given

  13. Pain Related Cortical Oscillations: Methodological Advances and Potential