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Sample records for biphasic osteoinductive calcium

  1. Influence of surface microstructure and chemistry on osteoinduction and osteoclastogenesis by biphasic calcium phosphate discs

    Directory of Open Access Journals (Sweden)

    NL Davison

    2015-06-01

    Full Text Available It has been reported that surface microstructural dimensions can influence the osteoinductivity of calcium phosphates (CaPs, and osteoclasts may play a role in this process. We hypothesised that surface structural dimensions of ≤ 1 μm trigger osteoinduction and osteoclast formation irrespective of macrostructure (e.g., concavities, interconnected macropores, interparticle space or surface chemistry. To test this, planar discs made of biphasic calcium phosphate (BCP: 80 % hydroxyapatite, 20 % tricalcium phosphate were prepared with different surface structural dimensions – either ~ 1 μm (BCP1150 or ~ 2-4 μm (BCP1300 – and no macropores or concavities. A third material was made by sputter coating BCP1150 with titanium (BCP1150Ti, thereby changing its surface chemistry but preserving its surface structure and chemical reactivity. After intramuscular implantation in 5 dogs for 12 weeks, BCP1150 formed ectopic bone in 4 out of 5 samples, BCP1150Ti formed ectopic bone in 3 out of 5 samples, and BCP1300 formed no ectopic bone in any of the 5 samples. In vivo, large multinucleated osteoclast-like cells densely colonised BCP1150, smaller osteoclast-like cells formed on BCP1150Ti, and osteoclast-like cells scarcely formed on BCP1300. In vitro, RAW264.7 cells cultured on the surface of BCP1150 and BCP1150Ti in the presence of osteoclast differentiation factor RANKL (receptor activator for NF-κB ligand proliferated then differentiated into multinucleated osteoclast-like cells with positive tartrate resistant acid phosphatase (TRAP activity. However, cell proliferation, fusion, and TRAP activity were all significantly inhibited on BCP1300. These results indicate that of the material parameters tested – namely, surface microstructure, macrostructure, and surface chemistry – microstructural dimensions are critical in promoting osteoclastogenesis and triggering ectopic bone formation.

  2. Muscle as an osteoinductive niche for local bone formation with the use of a biphasic calcium sulphate/hydroxyapatite biomaterial

    DEFF Research Database (Denmark)

    Raina, D. B.; Gupta, A.; Petersen, M. M.

    2016-01-01

    Objectives: We have observed clinical cases where bone is formed in the overlaying muscle covering surgically created bone defects treated with a hydroxyapatite/calcium sulphate biomaterial. Our objective was to investigate the osteoinductive potential of the biomaterial and to determine if growth...... factors secreted from local bone cells induce osteoblastic differentiation of muscle cells. Materials and Methods: We seeded mouse skeletal muscle cells C2C12 on the hydroxyapatite/calcium sulphate biomaterial and the phenotype of the cells was analysed. To mimic surgical conditions with leakage of extra...

  3. Biphasic calcium phosphate–casein bone graft fortified with Cassia

    Indian Academy of Sciences (India)

    Biphasic calcium phosphate; bone graft; Cassia occidentalis; simulated body fluid; SaOS-2 cell line. ... The study investigates the efficacy of CO extract incorporated biphasic calcium phosphate as an osteoinductive material. ... Current Issue

  4. Osteoinduction of calcium phosphate biomaterials in small animals

    International Nuclear Information System (INIS)

    Cheng, Lijia; Shi, Yujun; Ye, Feng; Bu, Hong

    2013-01-01

    Although osteoinduction mechanism of calcium phosphate (CP) ceramics is still unclear, several essential properties have been reported, such as chemical composition, pore size and porosity, etc. In this study, calcium phosphate powder (Ca 3 (PO 4 ) 2 , CaP, group 1), biphasic calcium phosphate ceramic powder (BCP, group 2), and intact BCP rods (group 3) were implanted into leg muscles of mice and dorsal muscles of rabbits. One month and three months after implantation, samples were harvested for biological and histological analysis. New bone tissues were observed in 10/10 samples in group 1, 3/10 samples in group 2, and 9/10 samples in group 3 at 3rd month in mice, but not in rabbits. In vitro, human mesenchymal stem cells (hMSCs) were cultured with trace CaP and BCP powder, and osteogenic differentiation was observed at day 7. Our results suggested that chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation. - Highlights: ► Intrinsic osteoinduction of calcium phosphate biomaterials was observed implanted in muscles of mice. ► Biomaterials powder also has osteoinduction property. ► Osteogenic genes and protein could be detected by RT-PCR and Western blot in implanted biomaterials. ► Osteogenic phenomenon could be observed by electron microscopy. ► The chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation

  5. Osteoinduction of calcium phosphate biomaterials in small animals

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Lijia; Shi, Yujun [Key Laboratory of Transplant Engineering and Immunology, Ministry of Health, West China Hospital, Sichuan University, Chengdu (China); Ye, Feng [Department of Pathology, West China Hospital, Sichuan University, Chengdu, 610041 (China); Bu, Hong, E-mail: hongbu@scu.edu.cn [Key Laboratory of Transplant Engineering and Immunology, Ministry of Health, West China Hospital, Sichuan University, Chengdu (China); Department of Pathology, West China Hospital, Sichuan University, Chengdu, 610041 (China)

    2013-04-01

    Although osteoinduction mechanism of calcium phosphate (CP) ceramics is still unclear, several essential properties have been reported, such as chemical composition, pore size and porosity, etc. In this study, calcium phosphate powder (Ca{sub 3}(PO{sub 4}){sub 2}, CaP, group 1), biphasic calcium phosphate ceramic powder (BCP, group 2), and intact BCP rods (group 3) were implanted into leg muscles of mice and dorsal muscles of rabbits. One month and three months after implantation, samples were harvested for biological and histological analysis. New bone tissues were observed in 10/10 samples in group 1, 3/10 samples in group 2, and 9/10 samples in group 3 at 3rd month in mice, but not in rabbits. In vitro, human mesenchymal stem cells (hMSCs) were cultured with trace CaP and BCP powder, and osteogenic differentiation was observed at day 7. Our results suggested that chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation. - Highlights: ► Intrinsic osteoinduction of calcium phosphate biomaterials was observed implanted in muscles of mice. ► Biomaterials powder also has osteoinduction property. ► Osteogenic genes and protein could be detected by RT-PCR and Western blot in implanted biomaterials. ► Osteogenic phenomenon could be observed by electron microscopy. ► The chemical composition is the prerequisite in osteoinduction, and pore structure would contribute to more bone formation.

  6. A Biphasic Calcium Sulphate/Hydroxyapatite Carrier Containing Bone Morphogenic Protein-2 and Zoledronic Acid Generates Bone

    DEFF Research Database (Denmark)

    Raina, Deepak Bushan; Isaksson, Hanna; Hettwer, Werner

    2016-01-01

    -the-shelf osteoinductive bone substitutes that can replace bone grafts are required. We tested the carrier properties of a biphasic, calcium sulphate and hydroxyapatite ceramic material, containing a combination of recombinant human bone morphogenic protein-2 (rhBMP-2) to induce bone, and zoledronic acid (ZA) to delay...

  7. The homing of bone marrow MSCs to non-osseous sites for ectopic bone formation induced by osteoinductive calcium phosphate

    Science.gov (United States)

    Song, Guodong; Habibovic, Pamela; Bao, Chongyun; Hu, Jing; van Blitterswijk, Clemens A.; Yuan, Huipin; Chen, Wenchuan; Xu, Hockin H.K.

    2013-01-01

    Osteoinductive biomaterials are promising for bone repair. There is no direct proof that bone marrow mesenchymal stem cells (BMSCs) home to non-osseous sites and participate in ectopic bone formation induced by osteoinductive bioceramics. The objective of this study was to use a sex-mismatched beagle dog model to investigate BMSC homing via blood circulation to participate in ectopic bone formation via osteoinductive biomaterial. BMSCs of male dogs were injected into female femoral marrow cavity. The survival and stable chimerism of donor BMSCs in recipients were confirmed with polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH). Biphasic calcium phosphate (BCP) granules were implanted in dorsal muscles of female dogs. Y chromosomes were detected in samples harvested from female dogs which had received male BMSCs. At 4 weeks, cells with Y-chromosomes were distributed in the new bone matrix throughout the BCP granule implant. At 6 weeks, cells with Y chromosomes were present in newly mineralized woven bone. TRAP positive osteoclast-like cells were observed in 4-week implants, and the number of such cells decreased from 4 to 6 weeks. These results show that osteoprogenitors were recruited from bone marrow and homed to ectopic site to serve as a cell source for calcium phosphate-induced bone formation. In conclusion, BMSCs were demonstrated to migrate from bone marrow through blood circulation to non-osseous bioceramic implant site to contribute to ectopic bone formation in a canine model. BCP induced new bone in muscles without growth factor delivery, showing excellent osteoinductivity that could be useful for bone tissue engineering. PMID:23298780

  8. Three dimensional biphasic calcium phosphate nanocomposites for load bearing bioactive bone grafts

    Energy Technology Data Exchange (ETDEWEB)

    Garai, Subhadra, E-mail: subha@nmlindia.org; Sinha, Arvind

    2016-02-01

    Mimicking matrix mediated bio-mineralization process, three dimensional blocks of biphasic calcium phosphate (BCP, hydroxyapatite (HA) and β-tricalcium phosphate (TCP)) nanocomposites, having three different stoichiometries have been synthesized for possible application as load bearing synthetic bone graft or scaffolds. Biphasic blocks with three weight ratios of 20:80, 25:75 and 30:70 of HA and TCP respectively have been synthesized. Detailed structural and chemical characterization of the samples revealed a strong dependence of porosity and mechanical properties on the stoichiometry of biphasic blocks. Effect of physiological medium on the microstructure and mechanical properties of the three different blocks has also been studied. Bioactivity of the BCP block, exhibiting highest compressive strength in air as well as in physiological medium, has been evaluated through adhesion, proliferation and differentiation of mesenchymal stem cells using different markers. - Highlights: • Developed a process for the synthesis of load bearing 3d- biphasic nanocomposites. • Synthesized nanocomposites exhibited in vitro osteoconductivity and osteoinductivity for bone marrow mesenchymal cells. • Developed process is a matrix mediated biomimetic one.

  9. Influence of octacalcium phosphate coating on osteoinductive properties of biomaterials

    NARCIS (Netherlands)

    Habibovic, Pamela; van der Valk, C.M.; van Blitterswijk, Clemens; de Groot, K.

    2004-01-01

    In this study, we investigated the influence of octacalcium phosphate (OCP) coating on osteoinductive behaviour of the biomaterials. Porous titanium alloy (Ti6Al4V), hydroxyapatite (HA), biphasic calcium phosphate (BCP) and polyethylene glyco terephtalate/polybuthylene terephtalate (PEGT–PBT)

  10. In vitro study on biomineralization of biphasic calcium phosphate ...

    Indian Academy of Sciences (India)

    In this study, we report the preparation of a bone graft material, having cylindrical shape, containing biphasic calcium phosphate (BCP), gelatin (G), chitosan (C) and Terminalia chebula (TC) extract. TC extract was used as a crosslinker that gives stability to bone graft when it is placed in SBF. The graft was stable in the SBF ...

  11. Preparation and Characterization of Apatitic Biphasic Calcium Phosphate

    International Nuclear Information System (INIS)

    Thin Thin Nwe; Kyaw Naing; Khin Mar Tun; Nyunt Wynn

    2005-09-01

    The apatitic biphasic calcium phosphate (ABcp) consisting of hydroxyapatite (HA) and -tricalcium phosphate ( -Tcp) has been prepared by precipitation technique using slaked lime and orthophosphoric acid. The X-ray diffraction analysis of the product I (hydroxyapatite) revealed that ABcp was partially crystalline state. However, on heating at 800 C for 8 hrs, XRD pattern indicated a perfectly crystalline form of ABcp. This observation was supported by FT-IR measurement. The change in morphology regarding in the functional nature was infered by the shift in the FT-IR frequency. The optimization of the apatitic biphasic calcium phosphate was done by the variation of disodium hydrogen phosphate concentration, setting time, hardening time as well as compressive strength. The perpared cement may be used as an artificial substitution bone

  12. Multi-scale osteointegration and neovascularization of biphasic calcium phosphate bone scaffolds

    Science.gov (United States)

    Lan, Sheeny K.

    Bone grafts are utilized clinically to guide tissue regeneration. Autologous bone and allogeneic bone are the current clinical standards. However, there are significant limitations to their use. To address the need for alternatives to autograft and allograft, researchers have worked to develop synthetic grafts, also referred to as scaffolds. Despite extensive efforts in this area, a gap persists between basic research and clinical application. In particular, solutions for repairing critical size and/or load-bearing defects are lacking. The aim of this thesis work was to address two critical barriers preventing design of successful tissue engineering constructs for bone regeneration within critical size and/or load-bearing defects. Those barriers are insufficient osteointegration and slow neovascularization. In this work, the effects of scaffold microporosity, recombinant human bone morphogenetic protein-2 delivery and endothelial colony forming cell vasculogenesis were evaluated in the context of bone formation in vivo. This was accomplished to better understand the role of these factors in bone regeneration, which may translate to improvements in tissue engineering construct design. Biphasic calcium phosphate (BCP) scaffolds with controlled macro- and microporosity were implanted in porcine mandibular defects. Evaluation of the BCP scaffolds after in vivo implantation showed, for the first time, osteocytes embedded in bone within scaffold micropores (macro and micro length scales, leaving no "dead space" or discontinuities of bone in the defect site. The scaffold forms a living composite upon integration with regenerating bone and this has significant implications with regard to improved scaffold mechanical properties. The presence of osteocytes within scaffold micropores is an indication of scaffold osteoinductivity because a chemotactic factor must be present to induce cell migration into pores on the order of the cell diameter. It is likely that the scaffold

  13. Facile synthesis of biphasic calcium phosphate microspheres with engineered surface topography for controlled delivery of drugs and proteins.

    Science.gov (United States)

    Zarkesh, Ibrahim; Ghanian, Mohammad Hossein; Azami, Mahmoud; Bagheri, Fatemeh; Baharvand, Hossein; Mohammadi, Javad; Eslaminejad, Mohamadreza Baghaban

    2017-09-01

    Biphasic calcium phosphate (BCP) microspheres are of great interest due to their high stability and osteoinductive properties at specific compositions. However, the need for optimal performance at a unique composition limits their flexibility for tuning drug release by modulation of bulk properties and presents the question of engineering surface topography as an alternative. It is necessary to have a facile method to control surface topography at a defined bulk composition. Here, we have produced BCP microspheres with different surface topographies that have the capability to be used as tunable drug release systems. We synthesized calcium deficient hydroxyapatite (CDHA) microparticles by precipitating calcium and phosphate ions onto ethylenediaminetetraacetic acid (EDTA) templates. The morphology and surface topography of CDHA microparticles were controlled using process parameters, which governed nucleation and growth. These parameters included template concentration, heat rate, and stirring speed. Under low heat rate and static conditions, we could obtain spherical microparticles with long and short nanosheets on their surfaces at low and high EDTA concentrations, respectively. These nanostructured microspheres were subsequently crystallized by thermal treatment to produce EDTA-free BCP microspheres with intact morphology. These biocompatible BCP microspheres were highly effective in loading and prolonged release of both small molecule [dexamethasone (Dex)] and protein [bovine serum albumin (BSA)] models. This strategy has enabled us to control the surface topography of BCP microspheres at defined compositions and holds tremendous promise for drug delivery and tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Response of stem cells from different origins to biphasic calcium phosphate bioceramics.

    Science.gov (United States)

    Lobo, Sonja E; Glickman, Robert; da Silva, Wagner N; Arinzeh, Treena L; Kerkis, Irina

    2015-08-01

    Biphasic calcium phosphate (BCP) bioceramics have been successfully applied in a broad variety of presentation forms and with different ratios of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). BCPs have been loaded with stem cells from different origins for bone tissue engineering purposes, but evidence of stem cell behavior on different compositions (various HA/β-TCP ratios) and physical features of BCPs is limited. We compared the adhesion, proliferation, viability and osteogenic potential of human mesenchymal stem cells (MSCs) on granular BCPs with equal HA/β-TCP ratio of diverse particle sizes and on porous blocks which had different chemical compositions. In addition, the osteogenic differentiation of MSCs was compared to adipose-derived (ADSC) and dental pulp (DPSC) stem cells, as well as to pre-osteoblasts on a particulate BCP. MSCs growing on granular BCPs demonstrated increased number as compared to MSCs growing on blocks. Cells proliferated to a greater extent on small granular BCPs, while large granular BCPs and blocks promoted cell differentiation. Surprisingly, the expression of genes involved in osteogenesis was upregulated in MSCs on bioceramics in basal medium which indicates that BCPs may have osteoinductive potential. This was confirmed with the upregulation of osteochondrogenic markers, at different time points, when stem cells from various tissues were grown on the BCP. This study demonstrates that BCPs, depending on their physical features and chemical composition, modulate stem cell behavior, and that stem cells from different origins are inherently distinct in their gene expression profile and can be triggered toward osteochondrogenic fate by BCPs.

  15. Preparation of dexamethasone-loaded biphasic calcium phosphate nanoparticles/collagen porous composite scaffolds for bone tissue engineering.

    Science.gov (United States)

    Chen, Ying; Kawazoe, Naoki; Chen, Guoping

    2018-02-01

    Although bone is regenerative, its regeneration capacity is limited. For bone defects beyond a critical size, further intervention is required. As an attractive strategy, bone tissue engineering (bone TE) has been widely investigated to repair bone defects. However, the rapid and effective bone regeneration of large non-healing defects is still a great challenge. Multifunctional scaffolds having osteoinductivity and osteoconductivity are desirable to fasten functional bone tissue regeneration. In the present study, biomimetic composite scaffolds of collagen and biphasic calcium phosphate nanoparticles (BCP NPs) with a controlled release of dexamethasone (DEX) and the controlled pore structures were prepared for bone TE. DEX was introduced in the BCP NPs during preparation of the BCP NPs and hybridized with collagen scaffolds, which pore structures were controlled by using pre-prepared ice particulates as a porogen material. The composite scaffolds had well controlled and interconnected pore structures, high mechanical strength and a sustained release of DEX. The composite scaffolds showed good biocompatibility and promoted osteogenic differentiation of hMSCs when used for three-dimensional culture of human bone marrow-derived mesenchymal stem cells. Subcutaneous implantation of the composite scaffolds at the dorsa of athymic nude mice demonstrated that they facilitated the ectopic bone tissue regeneration. The results indicated the DEX-loaded BCP NPs/collagen composite scaffolds had high potential for bone TE. Scaffolds play a crucial role for regeneration of large bone defects. Biomimetic scaffolds having the same composition of natural bone and a controlled release of osteoinductive factors are desirable for promotion of bone regeneration. In this study, composite scaffolds of collagen and biphasic CaP nanoparticles (BCP NPs) with a controlled release nature of dexamethasone (DEX) were prepared and their porous structures were controlled by using ice particulates

  16. The homing of bone marrow MSCs to non-osseous sites for ectopic bone formation induced by osteoinductive calcium phosphate.

    NARCIS (Netherlands)

    Song, G.; Habibovic, Pamela; Bao, Chongyun; Hu, J.; van Blitterswijk, Clemens; Yuan, Huipin; Chen, W.; Xu, H.H.K.

    2013-01-01

    Osteoinductive biomaterials are promising for bone repair. There is no direct proof that bone marrow mesenchymal stem cells (BMSCs) home to non-osseous sites and participate in ectopic bone formation induced by osteoinductive bioceramics. The objective of this study was to use a sex-mismatched

  17. A novel biphasic calcium phosphate derived from fish otoliths

    Science.gov (United States)

    Montañez-Supelano, N. D.; Sandoval-Amador, A.; Estupiñan-Durán, H. A.; Y Peña-Ballesteros, D.

    2017-12-01

    Calcium phosphates are bioceramics that have been widely used as bone substitutes because they encourage the formation of bone on their surface and can improve the healing of the bone. Hydroxyapatite HA (calcium/phosphorus ratio of 1.67) and tricalcium phosphate TCP (calcium/phosphorus ratio of 1.50) are the most common calcium phosphates. Natural materials have begun to be tested to make HA or TCP such as shells of cardiidae (family of mollusks) and eggshells. The calcium phosphate obtained has a high ability to precipitate apatite. In this work, the mixed phase ceramic of beta-Tri-calcium phosphate / hydroxyapatite (β-TCP/HA) was synthesized by aqueous precipitation from fish otoliths, which are monomineralic species composed of aragonite. Otoliths of the specie Plagioscion squamosissimus, commonly called the river croaker, were used. Techniques such as DRX, Raman spectroscopy and SEM-EDS were used to characterize the raw material and the obtained material. X-ray diffraction analysis revealed the presence of two crystalline phases of calcium phosphates with 86.2% crystallinity. SEM micrographs showed agglomeration of particles with porous structure and submicron particle sizes.

  18. Injectable biphasic calcium phosphate cements as a potential bone substitute

    NARCIS (Netherlands)

    Sariibrahimoglu, K.; Wolke, J.G.C.; Leeuwenburgh, S.C.G.; Yubao, L.; Jansen, J.A.

    2014-01-01

    Apatitic calcium phosphate cements (CPCs) have been widely used as bone grafts due to their excellent osteoconductive properties, but the degradation properties are insufficient to stimulate bone healing in large bone defects. A novel approach to overcome the lack of degradability of apatitic CPC

  19. Tailoring the structure of biphasic calcium phosphate via synthesis procedure

    Science.gov (United States)

    Mansour, S. F.; El-dek, S. I.; Ahmed, M. K.

    2017-12-01

    Nano calcium phosphate ceramics (CaPC) were synthesized using simple co-precipitation method at different preparation conditions. The selected Ca/P ratio with a variation of pH value lead to formation of dicalcium phosphate dihydrate (DCPD) at pH 5 and 6 while, hydroxyapatite (HAP) nano particles were formed at pH 9 and 12 at room temperature. The crystallite size was in the range of 15-55 nm depending on the obtained crystalline phase. The study displayed variation of decomposition depending on the annealing temperature. The significant note is the different transformation trend of each phase depending on the starting pH value. The HRTEM illustrated that the DCPD phase was formed as fibers with diameter around 4-6 nm, while HAP was formed in rod shape. The aspect ratio decreased from 6.6 at pH 9 to 4 at pH 12 which refer to the great influence of pH value on the morphology of calcium phosphates.

  20. A New Type of Biphasic Calcium Phosphate Cement as a Gentamicin Carrier for Osteomyelitis

    Directory of Open Access Journals (Sweden)

    Wen-Yu Su

    2013-01-01

    Full Text Available Osteomyelitis therapy is a long-term and inconvenient procedure for a patient. Antibiotic-loaded bone cements are both a complementary and alternative treatment option to intravenous antibiotic therapy for the treatment of osteomyelitis. In the current study, the biphasic calcium phosphate cement (CPC, called α-TCP/HAP (α-tricalcium phosphate/hydroxyapatite biphasic cement, was prepared as an antibiotics carrier for osteomyelitis. The developed biphasic cement with a microstructure of α-TCP surrounding the HAP has a fast setting time which will fulfill the clinical demand. The X-ray diffraction and Fourier transform infrared spectrometry analyses showed the final phase to be HAP, the basic bone mineral, after setting for a period of time. Scanning electron microscopy revealed a porous structure with particle sizes of a few micrometers. The addition of gentamicin in α-TCP/HAP would delay the transition of α-TCP but would not change the final-phase HAP. The gentamicin-loaded α-TCP/HAP supplies high doses of the antibiotic during the initial 24 hours when they are soaked in phosphate buffer solution (PBS. Thereafter, a slower drug release is produced, supplying minimum inhibitory concentration until the end of the experiment (30 days. Studies of growth inhibition of Staphylococcus aureus and Pseudomonas aeruginosa in culture indicated that gentamicin released after 30 days from α-TCP/HAP biphasic cement retained antibacterial activity.

  1. RF magnetron-sputtered coatings deposited from biphasic calcium phosphate targets for biomedical implant applications

    Directory of Open Access Journals (Sweden)

    K.A. Prosolov

    2017-09-01

    Full Text Available Bioactive calcium phosphate coatings were deposited by radio-frequency magnetron sputtering from biphasic targets of hydroxyapatite and tricalcium phosphate, sintered at different mass % ratios. According to Raman scattering and X-ray diffraction data, the deposited hydroxyapatite coatings have a disordered structure. High-temperature treatment of the coatings in air leads to a transformation of the quasi-amorphous structure into a crystalline one. A correlation has been observed between the increase in the Ca content in the coatings and a subsequent decrease in Ca in the biphasic targets after a series of deposition processes. It was proposed that the addition of tricalcium phosphate to the targets would led to a finer coating's surface topography with the average size of 78 nm for the structural elements.

  2. Biphasic stimulation of cellular calcium concentration by 3,5,3'-triiodothyronine in rat thymocytes

    International Nuclear Information System (INIS)

    Segal, J.

    1988-01-01

    3,5,3'-Triiodothyronine (T 3 ) produced a rapid and transient increase in 45 Ca uptake and cytoplasmic free calcium concentration in rat thymocytes, which is the most rapid effect of T 3 in this system. This effect was manifested in cells suspended in medium containing 1 mM calcium. The T 3 effect on 45 Ca uptake was evident at 15-30 s, reached maximum at 30-60 s, and returned to control values at 5 min. The T 3 effect on cytoplasmic free calcium concentration was seen after 30 s, reached maximum at 7 min, and returned to control values after 24 min. In cells suspended in Ca 2+ -free medium, T 3 produced a similar rapid increase in 45 Ca uptake, which was sustained for at least 60 min, but T 3 failed to change cytoplasmic free calcium concentration. Alprenolol (10 μM) blocked the stimulatory effects of T 3 on these two functions in a similar fashion. From these results, the authors suggest that in rat thymocytes T 3 influences cellular calcium economy through a biphasic mechanism in which T 3 first increases calcium uptake which, in turn, if followed by a release of calcium from intracellular pool(s), resulting in a further increase in cytoplasmic free calcium concentration and the activation of Ca 2+ -regulated systems. Moreover, the present study provides further support for the postulate that in the rat thymocyte calcium serves as the first messenger for the plasma membrane-mediated stimulatory effects of T 3 on several metabolic functions

  3. Alendronate-Eluting Biphasic Calcium Phosphate (BCP Scaffolds Stimulate Osteogenic Differentiation

    Directory of Open Access Journals (Sweden)

    Sung Eun Kim

    2015-01-01

    Full Text Available Biphasic calcium phosphate (BCP scaffolds have been widely used in orthopedic and dental fields as osteoconductive bone substitutes. However, BCP scaffolds are not satisfactory for the stimulation of osteogenic differentiation and maturation. To enhance osteogenic differentiation, we prepared alendronate- (ALN- eluting BCP scaffolds. The coating of ALN on BCP scaffolds was confirmed by scanning electron microscopy (FE-SEM, energy-dispersive X-ray spectroscopy (EDS, and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR. An in vitro release study showed that release of ALN from ALN-eluting BCP scaffolds was sustained for up to 28 days. In vitro results revealed that MG-63 cells grown on ALN-eluting BCP scaffolds exhibited increased ALP activity and calcium deposition and upregulated gene expression of Runx2, ALP, OCN, and OPN compared with the BCP scaffold alone. Therefore, this study suggests that ALN-eluting BCP scaffolds have the potential to effectively stimulate osteogenic differentiation.

  4. Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic

    International Nuclear Information System (INIS)

    He, Fupo; Ren, Weiwei; Tian, Xiumei; Liu, Wei; Wu, Shanghua; Chen, Xiaoming

    2016-01-01

    In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4 week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vivo response of CC/PG and biphasic calcium phosphate (BCP) was compared. • CC/PG showed faster in vitro degradation rate compared to BCP. • CC/PG showed less in vivo degradation and bone formation than BCP at week 4. • CC/PG had larger increment of degradation and bone formation than BCP at week 8.

  5. Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic

    Energy Technology Data Exchange (ETDEWEB)

    He, Fupo, E-mail: fphebm@126.com [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Ren, Weiwei [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Tian, Xiumei [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Liu, Wei; Wu, Shanghua [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Chen, Xiaoming, E-mail: xmchenw@126.com [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China)

    2016-07-01

    In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4 week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vivo response of CC/PG and biphasic calcium phosphate (BCP) was compared. • CC/PG showed faster in vitro degradation rate compared to BCP. • CC/PG showed less in vivo degradation and bone formation than BCP at week 4. • CC/PG had larger increment of degradation and bone formation than BCP at week 8.

  6. Synthesis of biphasic calcium phosphate containing nanostructured films by micro arc oxidation on magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Seyfoori, A., E-mail: klm.1985@yahoo.com [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); National Cell Bank, Pasteur Institute of Iran, 13164 Tehran (Iran, Islamic Republic of); Mirdamadi, Sh.; Seyedraoufi, Z.S.; Khavandi, A. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Aliofkhazraei, M. [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, 14115-143 Tehran (Iran, Islamic Republic of)

    2013-10-01

    The present research reports the synthesis of an innovative nanostructured composite film containing biphasic calcium phosphate (BCP) by the micro arc oxidation (MAO) method on AZ31 magnesium alloy. Nanometric structure of the used hydroxyapatite powder and the coatings were characterized by means of transmission and field-emission scanning electron microscope, respectively. Electrochemical behaviors of the pure MAO and nanocomposite films were also evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization tests in simulated body fluid (SBF) environment. The results showed higher corrosion resistance of nanocomposite film compared to pure MAO coating, which was related to the blocking feature of the nanoparticles from the diffusing of the corrosive medium through the substrate. In addition, by immersing the specimens in simulated body fluid, greater apatite forming ability of the nanocomposite coating was proved. - Highlights: • Synthesis of innovative biphasic calcium phosphate containing nanostructured films via micro arc oxidation. • Nanocomposite film has lower degradation rate than pure MAO film. • Greater apatite forming ability for nanocomposite coating compared with pure MAO film is obtained.

  7. Synthesis of biphasic calcium phosphate containing nanostructured films by micro arc oxidation on magnesium alloy

    International Nuclear Information System (INIS)

    Seyfoori, A.; Mirdamadi, Sh.; Seyedraoufi, Z.S.; Khavandi, A.; Aliofkhazraei, M.

    2013-01-01

    The present research reports the synthesis of an innovative nanostructured composite film containing biphasic calcium phosphate (BCP) by the micro arc oxidation (MAO) method on AZ31 magnesium alloy. Nanometric structure of the used hydroxyapatite powder and the coatings were characterized by means of transmission and field-emission scanning electron microscope, respectively. Electrochemical behaviors of the pure MAO and nanocomposite films were also evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization tests in simulated body fluid (SBF) environment. The results showed higher corrosion resistance of nanocomposite film compared to pure MAO coating, which was related to the blocking feature of the nanoparticles from the diffusing of the corrosive medium through the substrate. In addition, by immersing the specimens in simulated body fluid, greater apatite forming ability of the nanocomposite coating was proved. - Highlights: • Synthesis of innovative biphasic calcium phosphate containing nanostructured films via micro arc oxidation. • Nanocomposite film has lower degradation rate than pure MAO film. • Greater apatite forming ability for nanocomposite coating compared with pure MAO film is obtained

  8. Injectable TEMPO-oxidized nanofibrillated cellulose/biphasic calcium phosphate hydrogel for bone regeneration.

    Science.gov (United States)

    Safwat, Engie; Hassan, Mohammad L; Saniour, Sayed; Zaki, Dalia Yehia; Eldeftar, Mervat; Saba, Dalia; Zazou, Mohamed

    2018-05-01

    Nanofibrillated cellulose, obtained from rice straw agricultural wastes was used as a substrate for the preparation of a new injectable and mineralized hydrogel for bone regeneration. Tetramethyl pyridine oxyl (TEMPO) oxidized nanofibrillated cellulose, was mineralized through the incorporation of a prepared and characterized biphasic calcium phosphate at a fixed ratio of 50 wt%. The TEMPO-oxidized rice straw nanofibrillated cellulose was characterized using transmission electron microscopy, Fourier transform infrared, and carboxylic content determination. The injectability and viscosity of the prepared hydrogel were evaluated using universal testing machine and rheometer testing, respectively. Cytotoxicity and alkaline phosphatase level tests on osteoblast like-cells for in vitro assessment of the biocompatibility were investigated. Results revealed that the isolated rice straw nanofibrillated cellulose is a nanocomposite of the cellulose nanofibers and silica nanoparticles. Rheological properties of the tested materials are suitable for use as injectable material and of nontoxic effect on osteoblast-like cells, as revealed by the positive alkaline phosphate assay. However, nanofibrillated cellulose/ biphasic calcium phosphate hydrogel showed higher cytotoxicity and lower bioactivity test results when compared to that of nanofibrillated cellulose.

  9. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole

    Directory of Open Access Journals (Sweden)

    Byung-Chul Jeong

    2015-01-01

    Full Text Available Recently a submicron particle of biphasic calcium phosphate ceramic (BCP with through-hole (donut-shaped BCP (d-BCP was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM, energy dispersive spectroscopy (EDS, and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

  10. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole.

    Science.gov (United States)

    Jeong, Byung-Chul; Choi, Hyuck; Hur, Sung-Woong; Kim, Jung-Woo; Oh, Sin-Hye; Kim, Hyun-Seung; Song, Soo-Chang; Lee, Keun-Bae; Park, Kwang-Bum; Koh, Jeong-Tae

    2015-01-01

    Recently a submicron particle of biphasic calcium phosphate ceramic (BCP) with through-hole (donut-shaped BCP (d-BCP)) was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

  11. Synthesis, characterization and in vitro study of magnetic biphasic calcium sulfate-bioactive glass

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Yi-Fan; Akram, Muhammad; Alshemary, Ammar Z. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Darul Ta' zim (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@kimia.fs.utm.my [Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor Darul Ta' zim (Malaysia)

    2015-08-01

    Calcium sulfate-bioactive glass (CSBG) composites doped with 5, 10 and 20 mol% Fe were synthesized using quick alkali sol–gel method. X-ray diffraction (XRD) data of samples heated at 700 °C revealed the presence of anhydrite, while field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) characterization confirmed the formation of nano-sized CSBGs. The UV–vis studies confirmed that the main iron species in 5% Fe and 10% Fe doped CSBGs were tetrahedral Fe(III) whereas that in 20% Fe doped CSBG were extra-framework FeO{sub x} oligomers or iron oxide phases. Measurement of magnetic properties of the samples by vibrating sample magnetometer (VSM) showed very narrow hysteresis loop with zero coercivity and remanence for 10% Fe and 20% Fe doped CSBG, indicating that they are superparamagnetic in nature. All samples induced the formation of apatite layer with Ca/P ratio close to the stoichiometric HA in simulated body fluid (SBF) assessment. - Highlights: • Biphasic calcium sulphate-bioactive glass containing iron was prepared. • Composite bioglass was superparamagnetic in nature. • All samples promoted the growth of apatite layer with Ca/P close to 1.67.

  12. Direct 3D powder printing of biphasic calcium phosphate scaffolds for substitution of complex bone defects

    International Nuclear Information System (INIS)

    Castilho, Miguel; Pires, Inês; Moseke, Claus; Ewald, Andrea; Gbureck, Uwe; Groll, Jürgen; Teßmar, Jörg; Vorndran, Elke

    2014-01-01

    The 3D printing technique based on cement powders is an excellent method for the fabrication of individual and complex bone substitutes even in the case of large defects. The outstanding bone remodeling capacity of biphasic calcium phosphates (BCPs) containing hydroxyapatite (HA) as well as tricalcium phosphate (TCP) in varying ratios makes the adaption of powder systems resulting in BCP materials to this fabrication technique a desirable aim. This study presents the synthesis and characterization of a novel powder system for the 3D printing process, intended for the production of complexly shaped BCP scaffolds by a hydraulic setting reaction of calcium carbonate and TCP with phosphoric acid. The HA/TCP ratio in the specimens could be tailored by the calcium/phosphate ratio of the starting powder. The scaffolds could be fabricated with a dimensional accuracy of >96.5% and a minimal macro pore size of 300 µm. Independent of the phase composition the printed specimens showed a microporosity of approximately 68%, while the compressive strength strongly depended on the chemical composition and increased with rising TCP content in the scaffolds to a maximum of 1.81 MPa. Post-treatment of the scaffolds with a polylactic-co-glycolic acid-solution enhanced the mechanical properties by a factor of 8. In vitro studies showed that all BCP scaffolds were cytocompatible and enhanced the cell viability as well as the cell proliferation, as compared with pure TCP. Cell proliferation is even better on BCP when compared to HA and cell viability is in a similar range on these materials. (paper)

  13. The Effect of Reduced Graphene Oxide-Coated Biphasic Calcium Phosphate Bone Graft Material on Osteogenesis.

    Science.gov (United States)

    Kim, Jeong-Woo; Shin, Yong Cheol; Lee, Jin-Ju; Bae, Eun-Bin; Jeon, Young-Chan; Jeong, Chang-Mo; Yun, Mi-Jung; Lee, So-Hyoun; Han, Dong-Wook; Huh, Jung-Bo

    2017-08-08

    This study was conducted to evaluate the effect of biphasic calcium phosphate (BCP) coated with reduced graphene oxide (rGO) as bone graft materials on bone regeneration. The rGO-coated BCP bone graft material was fabricatied by mixing rGO and BCP at various concentrations. The surface charge of rGO-coated BCP was measured to be -14.43 mV, which formed a static electrostatic interaction. Cell viabilities were significantly diminished at higher concentrations of ≥100 μg/mL. The calvarial defects of 48 rats were implanted rGO-coated BCPs at a weight ratio of 2:1000 (rGO2), 4:1000 (rGO4), and 10:1000 (rGO10), repectively. BCP was used as a control group. The micro-CT and histological analysis were performed to evaluate new bone formation at 2 and 8 weeks after surgery. The results showed that the new bone volume (mm³) was significantly higher in the experimental groups than in the control group. Histological analysis showed that new bone areas (%) were significantly higher in the rGO2 and rGO10 than in the control, and significantly higher in rGO4 than in the rGO2 and rGO10. Conclusively, the rGO-coated BCP was found to be effective on osteogenesis and the concentration of the composite was an important factor.

  14. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application

    International Nuclear Information System (INIS)

    Baradaran, S.; Moghaddam, E.; Nasiri-Tabrizi, Bahman; Basirun, W.J.; Mehrali, M.; Sookhakian, M.; Hamdi, M.; Alias, Y.

    2015-01-01

    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3 wt.% and 6 wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900 °C for 1 h. The GNP (0.5–2 wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15 h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150 °C and 160 MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5 days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5 wt.% was the optimum value. - Highlights: • Ni doped biphasic calcium phosphate/graphene nanoplatelets composite was investigated. • Mechanical and biological properties were evaluated. • Phase compositions and structural features were influenced noticeably by the Ni and GNPs. • The cytotoxicity of the Ni was improved with the addition of GNPs

  15. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Baradaran, S., E-mail: saeid_baradaran@yahoo.com [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Moghaddam, E. [Tropical Infectious Diseases Research and Education Centre, Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Nasiri-Tabrizi, Bahman, E-mail: bahman_nasiri@hotmail.com [Advanced Materials Research Center, Materials Engineering Department, Najafabad Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Basirun, W.J. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Institute of Nanotechnology& Catalysis Research (NanoCat), University Malaya, 50603 Kuala Lumpur (Malaysia); Mehrali, M. [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Sookhakian, M. [Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Hamdi, M. [Center of Advanced Manufacturing and Material Processing, University of Malaya, 50603 Kuala Lumpur (Malaysia); Alias, Y. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2015-04-01

    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3 wt.% and 6 wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900 °C for 1 h. The GNP (0.5–2 wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15 h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150 °C and 160 MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5 days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5 wt.% was the optimum value. - Highlights: • Ni doped biphasic calcium phosphate/graphene nanoplatelets composite was investigated. • Mechanical and biological properties were evaluated. • Phase compositions and structural features were influenced noticeably by the Ni and GNPs. • The cytotoxicity of the Ni was improved with the addition of GNPs.

  16. Porous hydroxyapatite and biphasic calcium phosphate ceramics promote ectopic osteoblast differentiation from mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lingli; Fan Hongsong; Zhang Xingdong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, Sichuan 610064 (China); Hanagata, Nobutaka; Ikoma, Toshiyuki [Biomaterials Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Maeda, Megumi; Minowa, Takashi, E-mail: HANAGATA.Nobutaka@nims.go.j [Nanotechnology Innovation Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan)

    2009-04-15

    Because calcium phosphate (Ca-P) ceramics have been used as bone substitutes, it is necessary to investigate what effects the ceramics have on osteoblast maturation. We prepared three types of Ca-P ceramics with different Ca-P ratios, i.e. hydroxyapatite (HA), beta-tricalcium phosphate ({beta}-TCP), and biphasic calcium phosphate (BCP) ceramics with dense-smooth and porous structures. Comprehensive gene expression microarray analysis of mouse osteoblast-like cells cultured on these ceramics revealed that porous Ca-P ceramics considerably affected the gene expression profiles, having a higher potential for osteoblast maturation. In the in vivo study that followed, porous Ca-P ceramics were implanted into rat skeletal muscle. Sixteen weeks after the implantation, more alkaline-phosphatase-positive cells were observed in the pores of hydroxyapatite and BCP, and the expression of the osteocalcin gene (an osteoblast-specific marker) in tissue grown in pores was also higher in hydroxyapatite and BCP than in {beta}-TCP. In the pores of any Ca-P ceramics, 16 weeks after the implantation, we detected the expressions of marker genes of the early differentiation stage of chondrocytes and the complete differentiation stage of adipocytes, which originate from mesenchymal stem cells, as well as osteoblasts. These marker gene expressions were not observed in the muscle tissue surrounding the implanted Ca-P ceramics. These observations indicate that porous hydroxyapatite and BCP had a greater potential for promoting the differentiation of mesenchymal stem cells into osteoblasts than {beta}-TCP.

  17. Oily calcium hydroxide suspension (Osteoinductal) used as an adjunct to guided bone regeneration: an experimental study in rats.

    NARCIS (Netherlands)

    Stavropoulos, A.; Geenen, C.; Nyengaard, J.R.; Karring, T.; Sculean, A.

    2007-01-01

    OBJECTIVES: To evaluate whether an oily calcium hydroxide suspension (OCHS) promotes bone healing when used as an adjunct to guided bone regeneration (GBR). MATERIAL AND METHODS: Rigid, hemispherical, teflon capsules were placed with their open part facing the lateral surface of the ramus on both

  18. Synthesis, characterization and in vitro behavior of nanostructured diopside/biphasic calcium phosphate scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Ramezani, Samira; Emadi, Rahmatollah; Kharaziha, Mahshid [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Tavangarian, Fariborz, E-mail: f_tavangarian@yahoo.com [Mechanical Engineering Program, School of Science, Engineering and Technology, Penn State Harrisburg, Middletown, PA 17057 (United States)

    2017-01-15

    A significant challenge in bone tissue engineering is the development of 3D constructs serving as scaffolds to fill bone defects, support osteoblasts, and promote bone regeneration. In this paper, highly porous (∼79%) nanostructured diopside/biphasic calcium phosphate (BCP) scaffolds with interconnected porosity were developed using various diopside contents via space holder method. X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques were utilized to evaluate different samples. Furthermore, the effects of scaffold composition on mechanical properties, bioactivity, biodegradability, and cytotoxicity were studied as well. The results showed that the produced scaffolds had an average pore size and density of 200–340 μm and 2.5 ± 0.3–1.8 ± 0.3 gr/cm{sup 3}, respectively, depending on the diopside content. Besides, increasing the diopside content of scaffolds from 0 to 15 wt% enhanced the bioactivity, biodegradability, and compressive strength from 1.2 ± 0.2 to 3.2 ± 0.3 MPa, respectively. In addition, MTT assay also confirmed that the BCP15 scaffold (containing 15 wt% diopside) significantly promoted cell viability and cell adhesion compared to BCP0 scaffold. Overall, our study suggests that nanostructured diopside/BCP scaffolds with improved biological and mechanical properties could potentially be used for bone tissue engineering application. - Highlights: • Highly porous (∼79%) scaffolds were synthesized by space holder method. • Adding diopside nanopowder reduced the average pore size of the scaffolds. • Diopside increased the compressive strength of the scaffolds by three-times. • Nanostructured diopside/BCP scaffolds significantly promoted cell viability. • The nanostructured composite scaffold of BCP15 is cell-friendly.

  19. Micropore-induced capillarity enhances bone distribution in vivo in biphasic calcium phosphate scaffolds.

    Science.gov (United States)

    Rustom, Laurence E; Boudou, Thomas; Lou, Siyu; Pignot-Paintrand, Isabelle; Nemke, Brett W; Lu, Yan; Markel, Mark D; Picart, Catherine; Wagoner Johnson, Amy J

    2016-10-15

    The increasing demand for bone repair solutions calls for the development of efficacious bone scaffolds. Biphasic calcium phosphate (BCP) scaffolds with both macropores and micropores (MP) have improved healing compared to those with macropores and no micropores (NMP), but the role of micropores is unclear. Here, we evaluate capillarity induced by micropores as a mechanism that can affect bone growth in vivo. Three groups of cylindrical scaffolds were implanted in pig mandibles for three weeks: MP were implanted either dry (MP-Dry), or after submersion in phosphate buffered saline, which fills pores with fluid and therefore suppresses micropore-induced capillarity (MP-Wet); NMP were implanted dry. The amount and distribution of bone in the scaffolds were quantified using micro-computed tomography. MP-Dry had a more homogeneous bone distribution than MP-Wet, although the average bone volume fraction, BVF‾, was not significantly different for these two groups (0.45±0.03 and 0.37±0.03, respectively). There was no significant difference in the radial bone distribution of NMP and MP-Wet, but the BVF‾, of NMP was significantly lower among the three groups (0.25±0.02). These results suggest that micropore-induced capillarity enhances bone regeneration by improving the homogeneity of bone distribution in BCP scaffolds. The explicit design and use of capillarity in bone scaffolds may lead to more effective treatments of large and complex bone defects. The increasing demand for bone repair calls for more efficacious bone scaffolds and calcium phosphate-based materials are considered suitable for this application. Macropores (>100μm) are necessary for bone ingrowth and vascularization. However, studies have shown that microporosity (micropore-induced capillarity had the potential to enhance bone growth in vivo. This work illustrates the positive effects of capillarity on bone regeneration in vivo; it demonstrates that micropore-induced capillarity significantly

  20. Probing the limit of magnesium uptake by β-tricalcium phosphate in biphasic mixtures formed from calcium deficient apatites

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P. Nandha; Mishra, Sandeep K.; Kannan, S., E-mail: para_kanna@yahoo.com

    2015-11-15

    A series of magnesium doped non-stoichiometric calcium deficient apatites were synthesized through an aqueous precipitation route. The resultant structural changes during heat treatment were investigated by X-ray diffraction, Raman and FT-IR spectroscopy and Rietveld refinement. The results confirmed the formation of biphasic mixtures comprising Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} and β-Ca{sub 3}(PO{sub 4}){sub 2} after heat treatment at 1000 °C with the preferential occupancy of Mg{sup 2+} at the crystal lattice of β-Ca{sub 3}(PO{sub 4}){sub 2}. The concentration of Mg{sup 2+} uptake in β-Ca{sub 3}(PO{sub 4}){sub 2} is limited till reaching the stoichiometric ratio of (Ca+Mg)/P=1.67 and beyond this stoichiometric value [(Ca+Mg)/P>1.67], Mg{sup 2+} precipitates as Mg(OH){sub 2} and thereafter gets converted to MgO during heat treatment. Any kind of Mg{sup 2+} uptake in the crystal lattice of Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} is discarded from the investigation. - Highlights: • Aqueous co-precipitation of calcium deficient apatites with excess magnesium (Mg{sup 2+}) additions. • Heat treatments beyond 800 °C results in the formation of biphasic apatite mixtures. • Mg{sup 2+} gets accommodated at the β-Ca{sub 3}(PO{sub 4}){sub 2} lattice of biphasic mixtures. • Mg{sup 2+} additions exceeding stoichiometric value (Ca/P>1.67) results in its formation as MgO. • Mg{sup 2+} occupancy at β-Ca{sub 3}(PO{sub 4}){sub 2} lattice delays its allotropic conversion α-Ca{sub 3}(PO{sub 4}){sub 2} till 1350 °C.

  1. Bone healing around nanocrystalline hydroxyapatite, deproteinized bovine bone mineral, biphasic calcium phosphate, and autogenous bone in mandibular bone defects

    DEFF Research Database (Denmark)

    Broggini, Nina; Bosshardt, Dieter D; Jensen, Simon S

    2015-01-01

    The individual healing profile of a given bone substitute with respect to osteogenic potential and substitution rate must be considered when selecting adjunctive grafting materials for bone regeneration procedures. In this study, standardized mandibular defects in minipigs were filled...... with nanocrystalline hydroxyapatite (HA-SiO), deproteinized bovine bone mineral (DBBM), biphasic calcium phosphate (BCP) with a 60/40% HA/β-TCP (BCP 60/40) ratio, or particulate autogenous bone (A) for histological and histomorphometric analysis. At 2 weeks, percent filler amongst the test groups (DBBM (35.65%), HA......-SiO (34.47%), followed by BCP 60/40 (23.64%)) was significantly higher than the more rapidly substituted autogenous bone (17.1%). Autogenous bone yielded significantly more new bone (21.81%) over all test groups (4.91%-7.74%) and significantly more osteoid (5.53%) than BCP 60/40 (3%) and DBBM (2...

  2. Effect of biphasic calcium phosphate nanocomposite on healing of surgically created alveolar bone defects in beagle dogs

    Science.gov (United States)

    Wang, Lanlei; Guan, Aizhong; Shi, Han; Chen, Yangxi; Liao, Yunmao

    2009-09-01

    The aim of the present study was to investigate the effect of porous biphasic calcium phosphate nanocomposite (nanoBCP) scaffolds bioceramic. Alveolar bone defects were surgically created bilaterally at the buccal aspects of the upper second premolar in fourteen beagle dogs. After root conditioning with ethylenediaminetetraacetate (EDTA), nanoBCP was randomly filled in the defects and nothing was put into the contralaterals as controls. Dogs were killed at the 12th weeks. Histological observations were processed through a light microscopy. The results revealed that a great amount of functional periodontal fissures formed in the defects in the nanoBCP groups while minimal bone took shape in the controls. In this study, nanoBCP has proved to work well as a biocompatible and osteoconductive scaffold material to promote periodontal regeneration effectively.

  3. Structural and mechanical characterization of boron doped biphasic calcium phosphate produced by wet chemical method and subsequent thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Albayrak, Onder, E-mail: albayrakonder@mersin.edu.tr

    2016-03-15

    In the current study, boron doped biphasic calcium phosphate bioceramics consisting of a mixture of boron doped hydroxyapatite (BHA) and beta tricalcium phosphate (β-TCP) of varying BHA/β-TCP ratios were obtained after sintering stage. The effects of varying boron contents and different sintering temperatures on the BHA/β-TCP ratios and on the sinterability of the final products were investigated. Particle sizes and morphologies of the obtained precipitates were determined using SEM. XRD and FTIR investigation were conducted to detect the boron formation in the structure of HA and quantitative analysis was performed to determine the BHA/β-TCP ratio before and after sintering stage. In order to determine the sinterability of the obtained powders, pellets were prepared and sintered; the rates of densification were calculated and obtained results were correlated by SEM images. Also Vickers microhardness values of the sintered samples were determined. The experimental results verified that boron doped hydroxyapatite powders were obtained after sintering stage and the structure consists of a mixture of BHA and β-TCP. As the boron content used in the precipitation stage increases, β-TCP content of the BHA/β-TCP ratio increases but sinterability, density and microhardness deteriorate. As the sintering temperature increases, β-TCP content, density and microhardness of the samples increase and sinterability improves. - Highlights: • This is the first paper about boron doped biphasic calcium phosphate bioceramics. • Boron doping affects the structural and mechanical properties. • BHA/β-TCP ratio can be adjustable with boron content and sintering temperature.

  4. Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Webler, Geovana D. [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Correia, Ana C.C.; Barreto, Emiliano [Laboratório de Biologia Celular, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil); Fonseca, Eduardo J.S., E-mail: eduardo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, Maceió-AL 57072970 (Brazil)

    2015-07-15

    Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity.

  5. Biphasic regulation of intracellular calcium by gemfibrozil contributes to inhibiting L6 myoblast differentiation: implications for clinical myotoxicity.

    Science.gov (United States)

    Liu, Aiming; Yang, Julin; Gonzalez, Frank J; Cheng, Gary Q; Dai, Renke

    2011-02-18

    Gemfibrozil is the most myotoxic fibrate drug commonly used for dyslipidemia, but the mechanism is poorly understood. The current study revealed that gemfibrozil inhibits myoblast differentiation through the regulation of intracellular calcium ([Ca(2+)]i) as revealed in L6 myoblasts by use of laser scan confocal microscopy and flow cytometry using Fluo-4 AM as a probe. Gemfibrozil at 20-400 μM, could regulate [Ca(2+)]i in L6 cells in a biphasic manner, and sustained reduction was observed when the concentration reached 200 μM. Inhibition of L6 differentiation by gemfibrozil was concentration-dependent with maximal effect noted between 200 and 400 μM, as indicated by creatine kinase activities and the differentiation index, respectively. In differentiating L6 myoblasts, gemfibrozil at concentrations below 400 μM led to no significant signs of apoptosis or cytotoxicity, whereas differentiation, inhibited by 200 μM gemfibrozil, was only partially recovered. A good correlation was noted between gemfibrozil concentrations that regulate [Ca(2+)]i and inhibit L6 myoblasts differentiation, and both are within the range of total serum concentrations found in the clinic. These data suggest a potential pharmacodynamic effect of gemfibrozil on myogenesis as a warning sign, in addition to the complex pharmacokinetic interactions. It is also noteworthy that mobilization of [Ca(2+)]i by gemfibrozil may trigger complex biological responses besides myocyte differentiation. Information revealed in this study explores the mechanism of gemfibrozil-induced myotoxicity through the regulation of intracellular calcium.

  6. Mg-doped biphasic calcium phosphate by a solid state reaction route: Characterization and evaluation of cytotoxicity

    International Nuclear Information System (INIS)

    Webler, Geovana D.; Correia, Ana C.C.; Barreto, Emiliano; Fonseca, Eduardo J.S.

    2015-01-01

    Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) are widely used in tissue engineering because of their chemical similarity to the inorganic bone phase. In this work, we prepare biphasic calcium phosphate (BCP, a mixture of HAP and β-TCP) doped with different concentrations of magnesium to investigate the influence of magnesium on the BCP crystal structure. Magnesium is known to be an important element in the composition of bones and teeth. Recent research has shown that the doping of magnesium into BCP improves its bone metabolism and mechanical properties without affecting its biocompatibility. The samples were prepared by solid-state reaction from calcium carbonate, monobasic ammonium phosphate, and magnesium nitrate hexahydrate. Varying concentrations of magnesium were used and its modifications were examined by different characterization techniques. The phase composition and morphology of the ceramic powders were characterized by X-ray diffraction and scanning electron microscopy, respectively. The functional groups were analyzed using Fourier transform infrared spectroscopy and Raman spectroscopy. Cell viability experiments, using macrophage-like cell lines J774, showed that the synthesized Mg-doped BCP did not exhibit cytotoxicity regardless of the doses assayed or the different concentrations of magnesium used, suggesting it as a good material for potential biological applications. - Highlights: • Simple and fast method for the preparation of the Mg-BCP. • Study of the influence of the incorporation of Mg in the BCP. • Cell viability showed that the synthesized Mg-BCP did not exhibit cytotoxicity

  7. Comparative Efficacies of Collagen-Based 3D Printed PCL/PLGA/?-TCP Composite Block Bone Grafts and Biphasic Calcium Phosphate Bone Substitute for Bone Regeneration

    OpenAIRE

    Hwang, Kyoung-Sub; Choi, Jae-Won; Kim, Jae-Hun; Chung, Ho Yun; Jin, Songwan; Shim, Jin-Hyung; Yun, Won-Soo; Jeong, Chang-Mo; Huh, Jung-Bo

    2017-01-01

    The purpose of this study was to compare bone regeneration and space maintaining ability of three-dimensional (3D) printed bone grafts with conventional biphasic calcium phosphate (BCP). After mixing polycaprolactone (PCL), poly (lactic-co-glycolic acid) (PLGA), and ?-tricalcium phosphate (?-TCP) in a 4:4:2 ratio, PCL/PLGA/?-TCP particulate bone grafts were fabricated using 3D printing technology. Fabricated particulate bone grafts were mixed with atelocollagen to produce collagen-based PCL/P...

  8. Combined Effect of a Microporous Layer and Type I Collagen Coating on a Biphasic Calcium Phosphate Scaffold for Bone Tissue Engineering

    OpenAIRE

    Mun-Hwan Lee; Changkook You; Kyo-Han Kim

    2015-01-01

    In this study, type I collagen was coated onto unmodified and modified microporous biphasic calcium phosphate (BCP) scaffolds. Surface characterization using a scanning electron microscope (SEM) and a surface goniometer confirmed the modification of the BCP coating. The quantity of the collagen coating was investigated using Sirius Red staining, and quantitative assessment of the collagen coating showed no significant differences between the two groups. MG63 cells were used to evaluate cell p...

  9. The Effect of Covalently Immobilized FGF-2 on Biphasic Calcium Phosphate Bone Substitute on Enhanced Biological Compatibility and Activity

    Directory of Open Access Journals (Sweden)

    Kyung-Suk Moon

    2015-01-01

    Full Text Available The purpose of this research was to covalently graft fibroblast growth factor 2 (FGF-2 onto biphasic calcium phosphate (BCP via a bifunctional cross-linker technique and to estimate the optimal dose of FGF-2 resulting in the best osteogenic differentiation of human mesenchymal stem cells (hMSCs. SEM observation revealed that the surface of the 100 ng FGF-2 coated BCP was completely covered with the nanoparticles expected to be from the silane coupling agent. XRD, FT-IR, and XPS analysis showed that silane treatment, bifunctional cross-linker coating, and FGF-2 covalent grafts were conducted successfully without deforming the crystalline structure of BCP. An MTT assay demonstrated that FGF-2 coated BCP had good biocompatibility, regardless of the concentration of FGF-2, after 24 or 48 h of incubation. An alkaline phosphatase (ALP activity assay (14 days of incubation and the ALP gene expression level of real-time PCR analysis (7 days of incubation revealed that 50, 100, and 200 ng FGF-2 coated BCP induced the highest activities among all experimental groups and control group (P<0.05. Thus, low concentrations of FGF-2 facilitated excellent osteogenesis and were effective at enhancing osteogenic potential. Also, the bifunctional cross-linker technique is expected to be a more feasible way to induce osteogenic differentiation while minimizing the risk of FGF-2 overdose.

  10. Fabrication and materials properties of high-density polyethylene (HDPE)/biphasic calcium phosphate (BCP) hybrid bone plates

    International Nuclear Information System (INIS)

    Jo, Sun Young; Youn, Min Ho; Lim, Youn Mook; Gwon, Hui Jeong; Park, Jong Seok; Nho, Young Chang

    2010-01-01

    Biphasic calcium phosphate-reinforced high-density polyethylene (BCP/HDPE) hybrid composite is a new orthopedic biomaterial, which was made to simulate a natural bone composition. Calcium phosphate systems and HDPE hybrid composites have been used in biomedical applications without any inflammatory response. Differences in natural bone of both materials have motivated the use of coupling agents to improve their interfacial interfacial interactions. The composites were prepared using medical grade BCP powder and granular polyethylene. This material was produced by replacing the mineral component and collagen soft tissue of the bone with BCP and HDPE, respectively. As expected, increased volume fraction of either reinforcement type over 0 ∼ 50 vol.% resulted in a increased Vickers hardness and Young's modulus. Thus, BCP particle-reinforced HDPE composites possessed improved material and mechanical properties. BCP particles-reinforced composites were anisotropic due to an alignment of the particles in the matrix during a processing. On the other hand, bending and tensile strength was dramatically changed in the matrix. To change the material and mechanical properties of HDPE/BCP composites, the process of a blending was used, and its effect on the microstructure and mechanical proprieties of HDPE/BCP composites were investigated by means of FT-IR/ATR spectroscopy, XRD, FE-SEM, Vickers Hardness Testing Machine, Universal Testing Machine, Mercury Porosimeter and Ultrasonic Flaw Detector at room temperature. For the evaluation of the cell viability and proliferation onto the external surface of HDPE/BCP hybrid plates with a HaCaT cell line, which is a multipotent cell line able to differentiate towards different phenotypes under the action of biological factors, has been evaluated with in vitro studies and quantified by colormetric assays. These findings indicate that the HDPE/BCP hybrid plates are biocompatible and non-toxic

  11. Liposomal clodronate inhibition of osteoclastogenesis and osteoinduction by submicrostructured beta-tricalcium phosphate

    NARCIS (Netherlands)

    Davison, N.L.; Gambin, A.-L.; Layrolle, P.; Yuan, Huipin; de Bruijn, Joost Dick; Barrère-de Groot, F.

    2014-01-01

    Bone graft substitutes such as calcium phosphates are subject to the innate inflammatory reaction, which may bear important consequences for bone regeneration. We speculate that the surface architecture of osteoinductive β-tricalcium phosphate (TCP) stimulates the differentiation of invading

  12. Influence of saline solution on hydration behavior of β-dicalcium silicate in comparison with biphasic calcium phosphate/hydroxyapatite bio-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Radwan, M.M., E-mail: mmahmoudradwan@yahoo.com [Ceramics Dept, National Research Centre, Cairo (Egypt); Abd El-Hamid, H.K. [Ceramics Dept, National Research Centre, Cairo (Egypt); Mohamed, A.F. [The Holding Company for Production of Vaccines, Sera and Drugs (EGYVAC) (Egypt)

    2015-12-01

    The influence of using saline solution as mixing and curing liquid on some characteristics of β-dicalcium silicate (β-C{sub 2}S) and biphasic compound tri-calcium phosphate/hydroxyapatite (TCP/HAp) bio-ceramics was investigated. β-C{sub 2}S (27–30 nm) was prepared by solid state reaction at 1450 °C, while biphasic compound TCP/HAp (7–15 nm) was synthesized from an aqueous solution of Ca(NO{sub 3}){sub 2}·4H{sub 2}O and (NH{sub 4}){sub 2}HPO{sub 4}·12H{sub 2}O by chemical precipitation method. Setting times, compressive strength, pH values, X-ray diffraction analysis, infrared spectroscopy, scanning electron microscopy (SEM) were investigated. The evaluation of cytotoxicity of both calcium silicate and biphasic compounds to human gingival fibroblasts was carried out. The use of saline solution as mixing and immersing liquid shortened the setting time for the two bio-cements. TCP/HAp did not show any mechanical strength but β-C{sub 2}S showed good strength values. Both synthesized compounds showed a moderate cytotoxicity and both materials were effective in a no significant way. - Highlights: • The dissolution and hydration of β-C{sub 2}S and TCP/HAp in distilled water and saline solution were studied. • TCP/HAp did not show mechanical strength, while β-C{sub 2}S showed good mechanical strength. • The use of saline solution did enhances the dissolution & hydration rate. • An increase in pH values was detected when using saline solution. • Both materials showed a moderate cytotoxicity in no significant way.

  13. Properties and clinical relevance of osteoinductive biomaterials

    NARCIS (Netherlands)

    Habibovic, Pamela

    2005-01-01

    This thesis had two main goals: (¿) to investigate parameters influencing osteoinductive potential of biomaterials in order to unravel the mechanism underlying osteoinduction and (¿¿) to investigate performance of osteoinductive biomaterials orthotopically in order to get insight into their clinical

  14. A histomorphometric and micro-computed tomography study of bone regeneration in the maxillary sinus comparing biphasic calcium phosphate and deproteinized cancellous bovine bone in a human split-mouth model

    NARCIS (Netherlands)

    de Lange, G.L.; Overman, J.R.; Farre-Guasch, E.; Korstjens, C.M.; Hartman, B.; Langenbach, G.E.J.; van Duin, M.A.; Klein-Nulend, J.

    2014-01-01

    Objective The gain of mineralized bone was compared between deproteinized bovine bone allograft (DBA) and biphasic calcium phosphate (BCP) for dental implant placement. Study Design Five patients with atrophic maxillae underwent bilateral sinus elevation with DBA (Bio-Oss) and BCP (Straumann

  15. Combined Effect of a Microporous Layer and Type I Collagen Coating on a Biphasic Calcium Phosphate Scaffold for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Mun-Hwan Lee

    2015-03-01

    Full Text Available In this study, type I collagen was coated onto unmodified and modified microporous biphasic calcium phosphate (BCP scaffolds. Surface characterization using a scanning electron microscope (SEM and a surface goniometer confirmed the modification of the BCP coating. The quantity of the collagen coating was investigated using Sirius Red staining, and quantitative assessment of the collagen coating showed no significant differences between the two groups. MG63 cells were used to evaluate cell proliferation and ALP activity on the modified BCP scaffolds. The modified microporous surfaces showed low contact angles and large surface areas, which enhanced cell spreading and proliferation. Coating of the BCP scaffolds with type I collagen led to enhanced cell-material interactions and improved MG63 functions, such as spreading, proliferation, and differentiation. The micropore/collagen-coated scaffold showed the highest rate of cell response. These results indicate that a combination of micropores and collagen enhances cellular function on bioengineered bone allograft tissue.

  16. Study of hMSC proliferation and differentiation on Mg and Mg–Sr containing biphasic β-tricalcium phosphate and amorphous calcium phosphate ceramics

    International Nuclear Information System (INIS)

    Singh, Satish S.; Roy, Abhijit; Lee, Boeun; Kumta, Prashant N.

    2016-01-01

    Biphasic mixtures of either Mg"2"+ or combined Mg"2"+ and Sr"2"+ cation substituted β-tricalcium phosphate (β-TCP) and amorphous calcium phosphate (ACP) were prepared using a low temperature chemical phosphatizing and hydrolysis reaction approach. Scaffolds prepared using the cation substituted calcium phosphates were capable of supporting similar levels of human mesenchymal stem cell proliferation in comparison to commercially available β-TCP. The concentrations of Mg"2"+, Sr"2"+, and PO_4"3"− released from these scaffolds were also within the ranges desired from previous reports to support both hMSC proliferation and osteogenic differentiation. Interestingly, hMSCs cultured directly on scaffolds prepared with only Mg"2"+ substituted β-TCP were capable of supporting statistically significantly increased alkaline phosphatase activity, osteopontin, and osteoprotegerin expression in comparison to all compositions containing both Mg"2"+ and Sr"2"+, and commercially available β-TCP. hMSCs cultured in the presence of scaffold extracts also exhibited similar trends in the expression of osteogenic markers as was observed during direct culture. Therefore, it was concluded that the enhanced differentiation observed was due to the release of bioactive ions rather than the surface microstructure. The role of these ions on transforming growth factor-β and bone morphogenic protein signaling was also evaluated using a PCR array. It was concluded that the release of these ions may support enhanced differentiation through SMAD dependent TGF-β and BMP signaling. - Highlights: • Synthesis of Mg and Mg-Sr containing biphasic beta tricalcium phosphate ceramics • Magnesium substitution influences ALP activity compared to strontium content. • Solution extract plays a more dominant role on hMSC differentiation. • Direct and indirect Mg and Mg-Sr TCP culture show similar OPG and OPN expression.

  17. Study of hMSC proliferation and differentiation on Mg and Mg–Sr containing biphasic β-tricalcium phosphate and amorphous calcium phosphate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Satish S., E-mail: sss42@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Roy, Abhijit, E-mail: abr20@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Boeun [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261 (United States)

    2016-07-01

    Biphasic mixtures of either Mg{sup 2+} or combined Mg{sup 2+} and Sr{sup 2+} cation substituted β-tricalcium phosphate (β-TCP) and amorphous calcium phosphate (ACP) were prepared using a low temperature chemical phosphatizing and hydrolysis reaction approach. Scaffolds prepared using the cation substituted calcium phosphates were capable of supporting similar levels of human mesenchymal stem cell proliferation in comparison to commercially available β-TCP. The concentrations of Mg{sup 2+}, Sr{sup 2+}, and PO{sub 4}{sup 3−} released from these scaffolds were also within the ranges desired from previous reports to support both hMSC proliferation and osteogenic differentiation. Interestingly, hMSCs cultured directly on scaffolds prepared with only Mg{sup 2+} substituted β-TCP were capable of supporting statistically significantly increased alkaline phosphatase activity, osteopontin, and osteoprotegerin expression in comparison to all compositions containing both Mg{sup 2+} and Sr{sup 2+}, and commercially available β-TCP. hMSCs cultured in the presence of scaffold extracts also exhibited similar trends in the expression of osteogenic markers as was observed during direct culture. Therefore, it was concluded that the enhanced differentiation observed was due to the release of bioactive ions rather than the surface microstructure. The role of these ions on transforming growth factor-β and bone morphogenic protein signaling was also evaluated using a PCR array. It was concluded that the release of these ions may support enhanced differentiation through SMAD dependent TGF-β and BMP signaling. - Highlights: • Synthesis of Mg and Mg-Sr containing biphasic beta tricalcium phosphate ceramics • Magnesium substitution influences ALP activity compared to strontium content. • Solution extract plays a more dominant role on hMSC differentiation. • Direct and indirect Mg and Mg-Sr TCP culture show similar OPG and OPN expression.

  18. Tissue reaction and material biodegradation of a calcium sulfate/apatite biphasic bone substitute in rat muscle

    Directory of Open Access Journals (Sweden)

    Jian-Sheng Wang

    2016-07-01

    Conclusion: Calcium sulfate hydroxyapatite bone substitute can be used as a carrier for antibiotics or other drugs, without adverse reaction due to the fast resorption of the calcium sulfate. No bone formation was seen despite treating the bone substitute with autologous bone marrow.

  19. Surface modification of biphasic calcium phosphate scaffolds by non-thermal atmospheric pressure nitrogen and air plasma treatment for improving osteoblast attachment and proliferation

    International Nuclear Information System (INIS)

    Choi, Yu-Ri; Kwon, Jae-Sung; Song, Doo-Hoon; Choi, Eun Ha; Lee, Yong-Keun; Kim, Kyoung-Nam; Kim, Kwang-Mahn

    2013-01-01

    Surface modifications induced by non-thermal plasma have been used extensively in biomedical applications. The attachment and proliferation of osteoblast cells are important in bone tissue engineering using scaffolds. Hence the effect of non-thermal plasma on hydroxyapatite/β-tri-calcium phosphate (HA/β-TCP) scaffolds in terms of improving osteoblast attachment and proliferation was investigated. Experimental groups were treated with non-thermal plasma for 10 min and 20 min and a control group was not treated with non-thermal plasma. For surface chemistry analysis, X-ray photoelectron spectroscopy (XPS) analysis was carried out. The hydrophilicity was determined from contact angle measurement on the surface. Atomic force microscopy analysis (AFM) was used to test the change in surface roughness and cell attachment and proliferation were evaluated using MC3T3-E1 osteoblast cells. XPS spectra revealed a decreased amount of carbon on the surface of the plasma-treated sample. The contact angle was also decreased following plasma treatment, indicating improved hydrophilicity of plasma-treated surfaces compared to the untreated disc. A significant increase in MC3T3E-1 cell attachment and proliferation was noted on plasma-treated samples as compared to untreated specimens. The results suggest that non-thermal atmospheric pressure nitrogen and air plasma treatments provide beneficial surface characteristics on HA/β-TCP scaffolds. - Highlights: ► Non-thermal plasma increased OH- and decreased C on biphasic scaffold. ► Non-thermal plasma had no effect on surface roughness. ► Non-thermal plasma resulted in hydrophilic surface. ► Non-thermal plasma resulted in better cell attachment and proliferation. ► Non-thermal plasma treatment on biphasic scaffold is useful for tissue engineering

  20. Alveolar ridge augmentation by osteoinduction in rats

    DEFF Research Database (Denmark)

    Pinholt, E M; Bang, G; Haanaes, H R

    1990-01-01

    The purpose of this study was to evaluate bone substitutes for alveolar ridge augmentation by osteoinduction. Allogenic, demineralized, and lyophilized dentin and bone was tested for osteoinductive properties in order to establish an experimental model for further studies. Implantations were perf...

  1. Biphasic calcium phosphates (BCP of hydroxyapatite (HA and tricalcium phosphate (TCP as bone substitutes: Importance of physicochemical characterizations in biomaterials studies

    Directory of Open Access Journals (Sweden)

    Mehdi Ebrahimi

    2017-02-01

    Full Text Available The data presented in this article are related to the research article entitled “Biphasic calcium phosphates bioceramics (HA/TCP: Concept, physicochemical properties and the impact of standardization of study protocols in biomaterials research” [1]. This article provides in depth study of BCP bone substitutes as valuable option in the field of tissue engineering. However, there are discrepancies in the literature regarding the ideal physicochemical properties of BCP and the ideal balance between different phase compositions for enhanced bone tissue engineering (M. Ebrahimi, M.G. Botelho, S.V. Dorozhkin, 2016; M. Ebrahimi, P. Pripatnanont, S. Suttapreyasri, N. Monmaturapoj, 2014 [1,2]. This is found to be mainly because of improper characterization of BCP bioceramics in basic studies and lack of standard study protocols in in vitro and in vivo research. This data article along with original article provide the basic data required for ideal characterization of BCP and other bioceramics in an attempt to provide basic standardized protocols for future studies.

  2. Decontamination Using a Desiccant with Air Powder Abrasion Followed by Biphasic Calcium Sulfate Grafting: A New Treatment for Peri-Implantitis

    Directory of Open Access Journals (Sweden)

    Giorgio Lombardo

    2015-01-01

    Full Text Available Peri-implantitis is characterized by inflammation and crestal bone loss in the tissues surrounding implants. Contamination by deleterious bacteria in the peri-implant microenvironment is believed to be a major factor in the etiology of peri-implantitis. Prior to any therapeutic regenerative treatment, adequate decontamination of the peri-implant microenvironment must occur. Herein we present a novel approach to the treatment of peri-implantitis that incorporates the use of a topical desiccant (HYBENX, along with air powder abrasives as a means of decontamination, followed by the application of biphasic calcium sulfate combined with inorganic bovine bone material to augment the intrabony defect. We highlight the case of a 62-year-old man presenting peri-implantitis at two neighboring implants in positions 12 and 13, who underwent access flap surgery, followed by our procedure. After an uneventful 2-year healing period, both implants showed an absence of bleeding on probing, near complete regeneration of the missing bone, probing pocket depth reduction, and clinical attachment gain. While we observed a slight mucosal recession, there was no reduction in keratinized tissue. Based on the results described within, we conclude that the use of HYBENX and air powder abrasives, followed by bone defect grafting, represents a viable option in the treatment of peri-implantitis.

  3. Custom-Made Computer-Aided-Design/Computer-Aided-Manufacturing Biphasic Calcium-Phosphate Scaffold for Augmentation of an Atrophic Mandibular Anterior Ridge

    Directory of Open Access Journals (Sweden)

    Francesco Guido Mangano

    2015-01-01

    Full Text Available This report documents the clinical, radiographic, and histologic outcome of a custom-made computer-aided-design/computer-aided-manufactured (CAD/CAM scaffold used for the alveolar ridge augmentation of a severely atrophic anterior mandible. Computed tomographic (CT images of an atrophic anterior mandible were acquired and modified into a 3-dimensional (3D reconstruction model; this was transferred to a CAD program, where a custom-made scaffold was designed. CAM software generated a set of tool-paths for the manufacture of the scaffold on a computer-numerical-control milling machine into the exact shape of the 3D design. A custom-made scaffold was milled from a synthetic micromacroporous biphasic calcium phosphate (BCP block. The scaffold closely matched the shape of the defect: this helped to reduce the time for the surgery and contributed to good healing. One year later, newly formed and well-integrated bone was clinically available, and two implants (AnyRidge, MegaGen, Gyeongbuk, South Korea were placed. The histologic samples retrieved from the implant sites revealed compact mature bone undergoing remodelling, marrow spaces, and newly formed trabecular bone surrounded by residual BCP particles. This study demonstrates that custom-made scaffolds can be fabricated by combining CT scans and CAD/CAM techniques. Further studies on a larger sample of patients are needed to confirm these results.

  4. Bone Formation with Deproteinized Bovine Bone Mineral or Biphasic Calcium Phosphate in the Presence of Autologous Platelet Lysate: Comparative Investigation in Rabbit

    Directory of Open Access Journals (Sweden)

    Carole Chakar

    2014-01-01

    Full Text Available Bone substitutes alone or supplemented with platelet-derived concentrates are widely used to promote bone regeneration but their potency remains controversial. The aim of this study was, therefore, to compare the regenerative potential of preparations containing autologous platelet lysate (APL and particles of either deproteinized bovine bone mineral (DBBM or biphasic calcium phosphate (BCP, two bone substitutes with different resorption patterns. Rabbit APL was prepared by freeze-thawing a platelet suspension. Critical-size defects in rabbit femoral condyle were filled with DBBM or DBBM+APL and BCP or BCP+APL. Rabbits were sacrificed after six weeks and newly formed bone and residual implanted material were evaluated using nondemineralized histology and histomorphometry. New bone was observed around particles of all fillers tested. In the defects filled with BCP, the newly formed bone area was greater (70%; P<0.001 while the residual material area was lower (60%; P<0.001 than that observed in those filled with DBBM. New bone and residual material area of defects filled with either APL+DBBM or APL+BCP were similar to those observed in those filled with the material alone. In summary, osteoconductivity and resorption of BCP were greater than those of DBBM, while APL associated with either DBBM or BCP did not have an additional benefit.

  5. Biological characteristic effects of human dental pulp stem cells on poly-ε-caprolactone-biphasic calcium phosphate fabricated scaffolds using modified melt stretching and multilayer deposition.

    Science.gov (United States)

    Wongsupa, Natkrita; Nuntanaranont, Thongchai; Kamolmattayakul, Suttatip; Thuaksuban, Nuttawut

    2017-02-01

    Craniofacial bone defects such as alveolar cleft affect the esthetics and functions that need bone reconstruction. The advanced techniques of biomaterials combined with stem cells have been a challenging role for maxillofacial surgeons and scientists. PCL-coated biphasic calcium phosphate (PCL-BCP) scaffolds were created with the modified melt stretching and multilayer deposition (mMSMD) technique and merged with human dental pulp stem cells (hDPSCs) to fulfill the component of tissue engineering for bone substitution. In the present study, the objective was to test the biocompatibility and biofunctionalities that included cell proliferation, cell viability, alkaline phosphatase activity, osteocalcin, alizarin red staining for mineralization, and histological analysis. The results showed that mMSMD PCL-BCP scaffolds were suitable for hDPSCs viability since the cells attached and spread onto the scaffold. Furthermore, the constructs of induced hDPSCs and scaffolds performed ALP activity and produced osteocalcin and mineralized nodules. The results indicated that mMSMD PCL-BCP scaffolds with hDPSCs showed promise in bone regeneration for treatment of osseous defects.

  6. Biphasic calcium sulfate dihydrate/iron-modified alpha-tricalcium phosphate bone cement for spinal applications: in vitro study

    International Nuclear Information System (INIS)

    Vlad, M D; Lopez, J; Torres, R; Barraco, M; Fernandez, E; Valle, L J; Poeata, I

    2010-01-01

    In this study, the cytocompatibility of new 'iron-modified/alpha-tricalcium phosphate (IM/α-TCP) and calcium sulfate dihydrate (CSD)' bone cement (IM/α-TCP/CSD-BC) intended for spinal applications has been approached. The objective was to investigate by direct-contact osteoblast-like cell cultures (from 1 to 14 days) the in vitro cell adhesion, proliferation, morphology and cytoskeleton organization of MG-63 cells seeded onto the new cements. The results were as follows: (a) quantitative MTT-assay and scanning electron microscopy (SEM) showed that cell adhesion, proliferation and viability were not affected with time by the presence of iron in the cements; (b) double immunofluorescent labeling of F-actin and α-tubulin showed a dynamic interaction between the cell and its porous substrates sustaining the locomotion phenomenon on the cements' surface, which favored the colonization, and confirming the biocompatibility of the experimental cements; (c) SEM-cell morphology and cytoskeleton observations also evidenced that MG-63 cells were able to adhere, to spread and to attain normal morphology on the new IM/α-TCP/CSD-BC which offered favorable substratum properties for osteoblast-like cells proliferation and differentiation in vitro. The results showed that these new iron-modified cement-like biomaterials have cytocompatible features of interest not only as possible spinal cancellous bone replacement biomaterial but also as bone tissue engineering scaffolds.

  7. Effect of apatite formation of biphasic calcium phosphate ceramic (BCP) on osteoblastogenesis using simulated body fluid (SBF) with or without bovine serum albumin (BSA)

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Li [Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning (China); Department of Orthopaedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning (China); Zhou, Bo; Wu, Huayu [Department of Cell Biology & Genetics, School of Premedical Sciences, Guangxi Medical University, Nanning (China); Zheng, Li, E-mail: zhengli224@163.com [Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning (China); The Medical and Scientific Research Center, Guangxi Medical University, Nanning (China); Zhao, Jinmin, E-mail: zhaojinmin@126.com [Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning (China); Department of Orthopaedic Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning (China); Guangxi Colleges and Universities Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning (China)

    2017-01-01

    Although biphasic calcium phosphate ceramic (BCP) holds promise in therapy of bone defect, surface mineralization prior to implantation may improve the bioactivity to better integrate with the host. Immersion in simulated body fluid (SBF) and bovine serum albumin-simulated body fluid (BSA-SBF) are common methods to form apatite interface layer. This study was intended to investigate the effect of SBF and BSA-SBF treatment on the bioactivity of BCP in vitro. In this study, osteoblasts were grown on BCP with or without treatment of SBF or BSA-SBF, and detected with general observation, scanning electron microscope (SEM), cell proliferation assay, morphology observation, viability assay, alkaline phosphatase (ALP) activity assay, and osteogenic specific gene expression of alkaline phosphatase (ALPL), bone gamma-carboxyglutamate (gla) protein (BGLAP), bone morphogenetic protein 2 (BMP2), bone sialoprotein (BSP), type I collagen (COLI) and runt-related transcription factor 2 (RUNX2) after culture of 2, 5 and 8 days. As the results shown, BCP pre-incubated in SBF and BSA-SBF up-regulated ALP activity and osteogenic related genes and proteins, which testified the positive effect of SBF and BSA-SBF. Especially, BSA-SBF enhanced the cell growth significantly. This study indicated that treatment by BSA-SBF is of importance for BCP before clinical application. - Highlights: • BCP pre-incubated in SBF and BSA-SBF significantly promoted osteogenic differetiation of osteoblasts. • BSA-SBF enhanced the cell growth more significantly than SBF. • SBF may be a little toxic to osteoblasts.

  8. Platelet-rich plasma and bi-phasic tri calcium phosphate in the management of periodontally compromised teeth with hopeless prognosis: A case report with six-year follow-up and surgical re-entry

    Directory of Open Access Journals (Sweden)

    Subramoniam Sundaram

    2014-01-01

    Full Text Available One of the main objectives of periodontal therapy is to prolong the lifespan of dentition as there is no ideal substitute for natural dentition even in the era of dental implants. Treatment of teeth with advanced periodontal disease with hopeless prognosis is always extraction. However in this case report, we discuss a novel regenerative strategy using a combination of platelet rich plasma and bi-phasic tri calcium phosphate for a lower central incisor that was considered for extraction. Clinical and radiographic examination during the six-year follow-up postoperatively revealed stable periodontal health in the lower right central incisor. The surgical re-entry done in the sixth year postoperatively revealed good periradicular healing and alloplastic bone graft incorporation within the host bone.

  9. Analytical assessment of the osteoinductive material COLLOSSE

    DEFF Research Database (Denmark)

    Nienhuijs, M E L; Poulsen, K; van der Zande, M

    2009-01-01

    In this study, the growth factors in COLLOSSE were analyzed, using ELISA tests, mass spectrometry, western blotting, and a 24-day cell culture experiment using osteoblast-like cells. The results of the ELISA testing, mass spectrometry, and western blotting all confirmed that TGF-beta1 was the mai...... of osteoinductive factors in COLLOSSE causes a synergistic effect, explaining the new bone formation found in previously described in vivo studies, with much lower growth factor concentrations when compared with recombinant BMPs....

  10. Synthesis of Hydroxyapatite, β-Tricalcium Phosphate and Biphasic Calcium Phosphate Particles to Act as Local Delivery Carriers of Curcumin: Loading, Release and In Vitro Studies

    Directory of Open Access Journals (Sweden)

    Despoina Xidaki

    2018-04-01

    Full Text Available The successful synthesis of hydroxyapatite (HA, β-Tricalcium phosphate (β-TCP and two biphasic mixtures (BCPs of the two was performed by means of wet precipitation. The resulting crystals were characterized and the BCP composition was analyzed and identified as 13% HA—87% TCP and 41% HA—59% TCP. All samples were treated with curcumin solutions, and the degree of curcumin loading and release was found to be proportional to the TCP content of the ceramic. No further cytotoxicity was observed upon MG-63 treatment with the curcumin-loaded ceramics. Finally, the alkaline phosphatase activity of the cells was found to increase with increasing content of TCP, which provides an encouraging proof of concept for the use of curcumin-loaded synthetic biomaterials in bone remodeling.

  11. The fabrication of nanocomposites via calcium phosphate formation on gelatin–chitosan network and the gelatin influence on the properties of biphasic composites

    International Nuclear Information System (INIS)

    Babaei, Zahra; Jahanshahi, Mohsen; Rabiee, Sayed Mahmood

    2013-01-01

    A novel biodegradable polymer–ceramic nanocomposite which consisted of gelatin (Gel), chitosan (CS), and calcium phosphate (CaP) nanoparticles was prepared based on in situ preparation method. The fabricated biocomposites were characterized by FTIR, X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as scanning electron microscope with X-ray elemental analysis (SEM-EDX). The characterization results confirmed that the crystalline calcium phosphate nanoparticles were mineralized in polymeric matrix and the interaction between Ca2+ in calcium phosphate and functional groups in polymers molecular chains was formed. XRD result showed that in addition to hydroxyapatite (HA), Brushite (BR) and tricalcium phosphate (β-TCP) particles also were formed due to lack of complete penetration of the basic solution into the polymeric matrix. However, SEM image indicated that the polymeric matrix has the controlling role in the particle size of calcium phosphate. The size of particles in three component composites was about 100 nm while in two component composites proved to be more in μm size. TEM observation supported SEM results and showed that the three component composites have calcium phosphate nanoparticles. The elastic modulus and compressive strength of the composites were also improved by the employment of gelatin and chitosan together, which can make them more beneficial for surgical applications. - Highlights: ► A new type of calcium phosphate nanocomposites consisted chitosan and gelatin as polymeric matrix was obtained via in situ precipitation method. ► The formed particles into the polymeric matrix are hydroxyapatite, Brushite and β-tricalcium phosphate. ► The polymer concentration is a predominant factor for inhibiting nucleation and growth of calcium phosphate particles as the particles size was also decreased by increasing the amount of polymeric phase. ► The nano particles formed in three component composites and micro particles

  12. Calcium

    Science.gov (United States)

    ... You can get decent amounts of calcium from baked beans, navy beans, white beans, and others. Canned fish. You're in luck if you like sardines and canned salmon with bones. Almond milk. Working Calcium Into Your ...

  13. Nano-biphasic calcium phosphate/polyvinyl alcohol composites with enhanced bioactivity for bone repair via low-temperature three-dimensional printing and loading with platelet-rich fibrin.

    Science.gov (United States)

    Song, Yue; Lin, Kaifeng; He, Shu; Wang, Chunmei; Zhang, Shuaishuai; Li, Donglin; Wang, Jimeng; Cao, Tianqing; Bi, Long; Pei, Guoxian

    2018-01-01

    As a newly emerging three-dimensional (3D) printing technology, low-temperature robocasting can be used to fabricate geometrically complex ceramic scaffolds at low temperatures. Here, we aimed to fabricate 3D printed ceramic scaffolds composed of nano-biphasic calcium phosphate (BCP), polyvinyl alcohol (PVA), and platelet-rich fibrin (PRF) at a low temperature without the addition of toxic chemicals. Corresponding nonprinted scaffolds were prepared using a freeze-drying method. Compared with the nonprinted scaffolds, the printed scaffolds had specific shapes and well-connected internal structures. The incorporation of PRF enabled both the sustained release of bioactive factors from the scaffolds and improved biocompatibility and biological activity toward bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. Additionally, the printed BCP/PVA/PRF scaffolds promoted significantly better BMSC adhesion, proliferation, and osteogenic differentiation in vitro than the printed BCP/PVA scaffolds. In vivo, the printed BCP/PVA/PRF scaffolds induced a greater extent of appropriate bone formation than the printed BCP/PVA scaffolds and nonprinted scaffolds in a critical-size segmental bone defect model in rabbits. These experiments indicate that low-temperature robocasting could potentially be used to fabricate 3D printed BCP/PVA/PRF scaffolds with desired shapes and internal structures and incorporated bioactive factors to enhance the repair of segmental bone defects.

  14. Feasibility and safety of treating non-unions in tibia, femur and humerus with autologous, expanded, bone marrow-derived mesenchymal stromal cells associated with biphasic calcium phosphate biomaterials in a multicentric, non-comparative trial.

    Science.gov (United States)

    Gómez-Barrena, Enrique; Rosset, Philippe; Gebhard, Florian; Hernigou, Philippe; Baldini, Nicola; Rouard, Helène; Sensebé, Luc; Gonzalo-Daganzo, Rosa M; Giordano, Rosaria; Padilla-Eguiluz, Norma; García-Rey, Eduardo; Cordero-Ampuero, José; Rubio-Suárez, Juan Carlos; Stanovici, Julien; Ehrnthaller, Christian; Huber-Lang, Markus; Flouzat-Lachaniette, Charles Henri; Chevallier, Nathalie; Donati, Davide Maria; Ciapetti, Gabriela; Fleury, Sandrine; Fernandez, Manuel-Nicolás; Cabrera, José-Rafael; Avendaño-Solá, Cristina; Montemurro, Tiziana; Panaitescu, Carmen; Veronesi, Elena; Rojewski, Markus Thomas; Lotfi, Ramin; Dominici, Massimo; Schrezenmeier, Hubert; Layrolle, Pierre

    2018-03-19

    ORTHO-1 is a European, multicentric, first in human clinical trial to prove safety and feasibility after surgical implantation of commercially available biphasic calcium phosphate bioceramic granules associated during surgery with autologous mesenchymal stromal cells expanded from bone marrow (BM-hMSC) under good manufacturing practices, in patients with long bone pseudarthrosis. Twenty-eight patients with femur, tibia or humerus diaphyseal or metaphyso-diaphyseal non-unions were recruited and surgically treated in France, Germany, Italy and Spain with 100 or 200 million BM-hMSC/mL associated with 5-10 cc of bioceramic granules. Patients were followed up during one year. The investigational advanced therapy medicinal product (ATMP) was expanded under the same protocol in all four countries, and approved by each National Competent Authority. With safety as primary end-point, no severe adverse event was reported as related to the BM-hMSC. With feasibility as secondary end-point, the participating production centres manufactured the BM-hMSC as planned. The ATMP combined to the bioceramic was surgically delivered to the non-unions, and 26/28 treated patients were found radiologically healed at one year (3 out of 4 cortices with bone bridging). Safety and feasibility were clinically proven for surgical implantation of expanded autologous BM-hMSC with bioceramic. EU-FP7-HEALTH-2009, REBORNE Project (GA: 241876). Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. A review paper on biomimetic calcium phosphate coatings

    NARCIS (Netherlands)

    Lin, X.; de Groot, K.; Wang, D.; Hu, Q.; Wismeijer, D.; Liu, Y.

    2015-01-01

    Biomimetic calcium phosphate coatings have been developed for bone regeneration and repair because of their biocompatibility, osteoconductivity, and easy preparation. They can be rendered osteoinductive by incorporating an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2), into the

  16. Alveolar ridge augmentation by osteoinductive materials in goats

    DEFF Research Database (Denmark)

    Pinholt, E M; Haanaes, H R; Roervik, M

    1992-01-01

    The purpose of the present study was to determine whether alveolar ridge augmentation could be induced in goats. In 12 male goats allogenic, demineralized, and lyophilized dentin or bone was implanted subperiosteally on the buccal sides of the natural edentulous regions of the alveolar process...... of the mandible. Light microscopic evaluation revealed fibrous encapsulation, a few multinuclear giant cells, little inflammatory reaction, and no osteoinduction. It was concluded that no osteoinduction took place in goats....

  17. Raman study of the repair of surgical bone defects grafted with biphasic synthetic microgranular HA + β-calcium triphosphate and irradiated or not with λ780 nm laser.

    Science.gov (United States)

    Soares, Luiz Guilherme P; Marques, Aparecida Maria C; Barbosa, Artur Felipe S; Santos, Nicole R; Aciole, Jouber Mateus S; Souza, Caroline Mathias C; Pinheiro, Antonio Luiz B; Silveira, Landulfo

    2014-09-01

    The treatment of bone loss due to different etiologic factors is difficult, and many techniques aim to improve repair, including a wide range of biomaterials and, recently, photobioengineering. This work aimed to assess, through Raman spectroscopy, the level of bone mineralization using the intensities of the Raman peaks of both inorganic (∼ 960, ∼ 1,070, and ∼ 1,077 cm(-1)) and organic (∼ 1,454 and ∼ 1,666 cm(-1)) contents of bone tissue. Forty rats were divided into four groups each subdivided into two subgroups according to the time of killing (15 and 30 days). Surgical bone defects were made on femur of each animal with a trephine drill. On animals of group Clot, the defect was filled only by blood clot; on group Laser, the defect filled with the clot was further irradiated. On animals of groups Biomaterial and Laser + Biomaterial, the defect was filled by biomaterial and the last one was further irradiated (λ780 nm, 70 mW, Φ ∼ 0.4 cm(2), 20 J/cm(2) session, 140 J/cm(2) treatment) in four points around the defect at 48-h intervals and repeated for 2 weeks. At both 15th and 30th day following killing, samples were taken and analyzed by Raman spectroscopy. At the end of the experimental time, the intensities of both inorganic and organic contents were higher on group Laser + Biomaterial. It is concluded that the use of laser phototherapy associated to biomaterial was effective in improving bone healing on bone defects as a result of the increasing deposition of calcium hydroxyapatite measured by Raman spectroscopy.

  18. Influence of the λ780nm laser light on the repair of surgical bone defects grafted or not with biphasic synthetic micro-granular hydroxylapatite+Beta-Calcium triphosphate.

    Science.gov (United States)

    Soares, Luiz Guilherme P; Marques, Aparecida Maria C; Guarda, Milena G; Aciole, Jouber Mateus S; dos Santos, Jean Nunes; Pinheiro, Antonio Luiz B

    2014-02-05

    The treatment of bone loss due to different etiologic factors is difficult and many techniques aim to improve repair, including a wide range of biomaterials and, recently, photobioengineering. This work aimed to assess, through histological analysis The aim of this study was to assess, by light microscopy, the repair of bone defects grafted or not with biphasic synthetic micro-granular Calcium hydroxyapatite (HA)+Beta-TCP associated or not with Laser phototherapy - LPT (λ780nm). Forty rats were divided into 4 groups each subdivided into 2 subgroups according to the time of sacrifice (15 and 30days). Surgical bone defects were made on femur of each animal with a trephine drill. On animals of Clot group the defect was filled only by blood clot, on Laser group the defect filled with the clot was further irradiated. On animals of Biomaterial and Laser+Biomaterial groups the defect was filled by biomaterial and the last one was further irradiated (λ780nm, 70mW, spot size∼0.4cm(2), 20J/cm(2)-session, 140J/cm(2)-treatment) in four points around the defect at 48-h intervals and repeated for 2weeks. At both 15th and 30th days following sacrifice, samples were taken and analyzed by light microscopy. Many similarities were observed histologically between groups on regards bone reabsorption and neoformation, inflammatory infiltrate and collagen deposition. The criterion degree of maturation, marked by the presence of basophilic lines, indicated that the use of LPT associated with HA+Beta TCP graft, resulted in more advanced stage of bone repair at the end of the experiment. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Microporous calcium phosphate ceramics driving osteogenesis through surface architecture.

    Science.gov (United States)

    Zhang, Jingwei; Barbieri, Davide; ten Hoopen, Hetty; de Bruijn, Joost D; van Blitterswijk, Clemens A; Yuan, Huipin

    2015-03-01

    The presence of micropores in calcium phosphate (CaP) ceramics has shown its important role in initiating inductive bone formation in ectopic sites. To investigate how microporous CaP ceramics trigger osteoinduction, we optimized two biphasic CaP ceramics (i.e., BCP-R and BCP-S) to have the same chemical composition, equivalent surface area per volume, comparable protein adsorption, similar ion (i.e., calcium and phosphate) exchange and the same surface mineralization potential, but different surface architecture. In particular, BCP-R had a surface roughness (Ra) of 325.4 ± 58.9 nm while for BCP-S it was 231.6 ± 35.7 nm. Ceramic blocks with crossing or noncrossing channels of 250, 500, 1000, and 2000 µm were implanted in paraspinal muscle of dogs for 12 weeks. The percentage of bone volume in the channels was not affected by the type of pores (i.e., crossing vs. closed) or their size, but it was greatly influenced by the ceramic type (i.e., BCP-R vs. BCP-S). Significantly, more bone was formed in the channels of BCP-R than in those of BCP-S. Since the two CaP ceramics differed only in their surface architecture, the results hereby demonstrate that microporous CaP ceramics may induce ectopic osteogenesis through surface architecture. © 2014 Wiley Periodicals, Inc.

  20. Osteoinductive potential of demineralized rat bone increases with increasing donor age from birth to adulthood

    DEFF Research Database (Denmark)

    Pinholt, E M; Solheim, E

    1998-01-01

    Demineralized allogenic bone implanted in the subcutis or muscle of rodents causes formation of heterotopic bone by osteoinduction. The osteoinductive response may be weaker in primates than in rodents. It was suggested that the osteoinductive response of demineralized bone for clinical use could...... be enhanced by using young donors, because studies have indicated that the osteoinductive response is reduced in demineralized bone of old versus young donors. However, these findings may not represent a gradual decline in the osteoinductive property of bone matrix throughout the life span. We evaluated...... quantitatively, by uptake of strontium 85, the osteoinductive effect of demineralized bone matrix from newborn, 8-week-old (adolescent), and 8-month-old (adult) male Wistar rats implanted in the abdominal muscles of 8-week-old male Wistar rats. The osteoinductive response increased significantly with increasing...

  1. Radiation demineralised bone enhanced osteoinductive capacity after transplantation

    International Nuclear Information System (INIS)

    Phillips, G.O.; Al-Assaf, S.; Williams, P.A.; Plessis, A. du; Yim, C.J.

    2007-01-01

    Using a mediating alkyne gas during the radiation treatment prevents the degradation of natural and synthetic polysaccharides and proteins. The product has higher viscosity and is more elastic than the original material and, therefore, gives enhanced functionality. Protein, within demineralised bone, too can be modified to give enhanced osteoinductive capacity after transplantation. Thus new functionalities can be achieved from the new products produced in food and medical products

  2. Osteoinductive biomaterials: current knowledge of properties, experimental models and biological mechanisms

    NARCIS (Netherlands)

    Barradas, A.M.C.; Yuan, Huipin; van Blitterswijk, Clemens; Habibovic, Pamela

    2010-01-01

    In the past thirty years, a number of biomaterials have shown the ability to induce bone formation when implanted at heterotopic sites, an ability known as osteoinduction. Such biomaterials – osteoinductive biomaterials – hold great potential for the development of new therapies in bone

  3. Intrinsic Osteoinductivity of Porous Titanium Scaffold for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Maryam Tamaddon

    2017-01-01

    Full Text Available Large bone defects and nonunions are serious complications that are caused by extensive trauma or tumour. As traditional therapies fail to repair these critical-sized defects, tissue engineering scaffolds can be used to regenerate the damaged tissue. Highly porous titanium scaffolds, produced by selective laser sintering with mechanical properties in range of trabecular bone (compressive strength 35 MPa and modulus 73 MPa, can be used in these orthopaedic applications, if a stable mechanical fixation is provided. Hydroxyapatite coatings are generally considered essential and/or beneficial for bone formation; however, debonding of the coatings is one of the main concerns. We hypothesised that the titanium scaffolds have an intrinsic potential to induce bone formation without the need for a hydroxyapatite coating. In this paper, titanium scaffolds coated with hydroxyapatite using electrochemical method were fabricated and osteoinductivity of coated and noncoated scaffolds was compared in vitro. Alizarin Red quantification confirmed osteogenesis independent of coating. Bone formation and ingrowth into the titanium scaffolds were evaluated in sheep stifle joints. The examinations after 3 months revealed 70% bone ingrowth into the scaffold confirming its osteoinductive capacity. It is shown that the developed titanium scaffold has an intrinsic capacity for bone formation and is a suitable scaffold for bone tissue engineering.

  4. Accelerated healing by composites containing herb epimedium for osteoinductive regeneration

    International Nuclear Information System (INIS)

    Wang, J; Tian, X F; Wu, S Y; Meng, X C; Wen, G W

    2014-01-01

    Porous composites composed of hydroxyapatite (HA), herb epimedium (EP), and chitosan (CS) were used to improve the repair of rabbit bone defects. The in vivo implantation of the HA/CS-EP showed that homogeneous bone formation occurred after 12 weeks' implantation and possessed good osteogenesis. The osteogenic process of the HA/CS-EP group was different from that of the HA/CS group. Direct bone formation of osteoblasts with HA/CS-EP as the matrix could be observed. Compared with the group filled with HA/CS, the group filled with HA/CS-EP showed significant increases in the number of osteoblasts and the bone formation area, and the areas of new bone formation in the HA/CS-EP group after 4 or 12 weeks' implantation reached 33% and 87%, respectively. The novel repair system of HA/CS-EP can induce bone formation, increase osteoblast quantity and improve osteogenesis, for EP can significantly promote the proliferation and activity of osteoblasts in the early stage and accelerate bone remodeling in the later stage. Composites containing EP could be a promising material with multifunctions of osteoinduction, osteoconduction and medication for bone repair, and herb medicine EP could be used as an osteoinduction material for bone tissue engineering. (paper)

  5. The chemical composition of synthetic bone substitutes influences tissue reactions in vivo: histological and histomorphometrical analysis of the cellular inflammatory response to hydroxyapatite, beta-tricalcium phosphate and biphasic calcium phosphate ceramics

    International Nuclear Information System (INIS)

    Ghanaati, Shahram; Barbeck, Mike; Hilbig, Ulrike; Rausch, Vera; Unger, Ronald E; Kirkpatrick, Charles James; Detsch, Rainer; Ziegler, Guenter; Deisinger, Ulrike; Sader, Robert

    2012-01-01

    Bone substitute material properties such as granule size, macroporosity, microporosity and shape have been shown to influence the cellular inflammatory response to a bone substitute material. Keeping these parameters constant, the present study analyzed the in vivo tissue reaction to three bone substitute materials (granules) with different chemical compositions (hydroxyapatite (HA), beta-tricalcium phosphate (TCP) and a mixture of both with a HA/TCP ratio of 60/40 wt%). Using a subcutaneous implantation model in Wistar rats for up to 30 days, tissue reactions, including the induction of multinucleated giant cells and the extent of implantation bed vascularization, were assessed using histological and histomorphometrical analyses. The results showed that the chemical composition of the bone substitute material significantly influenced the cellular response. When compared to HA, TCP attracted significantly greater multinucleated giant cell formations within the implantation bed. Furthermore, the vascularization of the implantation bed of TCP was significantly higher than that of HA implantation beds. The biphasic bone substitute group combined the properties of both groups. Within the first 15 days, high giant cell formation and vascularization rates were observed, which were comparable to the TCP-group. However, after 15 days, the tissue reaction, i.e. the extent of multinucleated giant cell formation and vascularization, was comparable to the HA-group. In conclusion, the combination of both compounds HA and TCP may be a useful combination for generating a scaffold for rapid vascularization and integration during the early time points after implantation and for setting up a relatively slow degradation. Both of these factors are necessary for successful bone tissue regeneration.

  6. Calcium phosphate implants coatings as carriers for BMP-2

    NARCIS (Netherlands)

    Liu, Y.; He, J.F.; Hunziker, E.B.

    2009-01-01

    The osteoconductivity of dental implants can be improved by coating them with a layer of calcium phosphate (CaP), which can be rendered osteoinductive by functionalizing it with an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2). In the present study, we wished to compare the

  7. Sintered porous hydroxyapatites with intrinsic osteoinductive activity: geometric induction of bone formation

    CSIR Research Space (South Africa)

    Ripamonti, U

    1999-08-01

    Full Text Available Sintered hydroxyapatites induce bone formation in adult baboons via intrinsic osteoinductivity regulated by the geometry of the substratum. Bone is thereby formed without exogenous bone morphogenetic proteins (BMPs), well-characterized inducers...

  8. Osteoinductive recombinant silk fusion proteins for bone regeneration.

    Science.gov (United States)

    Dinjaski, Nina; Plowright, Robyn; Zhou, Shun; Belton, David J; Perry, Carole C; Kaplan, David L

    2017-02-01

    Protein polymers provide a unique opportunity for tunable designs of material systems due to the genetic basis of sequence control. To address the challenge of biomineralization interfaces with protein based materials, we genetically engineered spider silks to design organic-inorganic hybrid systems. The spider silk inspired domain (SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQGT) 15 served as an organic scaffold to control material stability and to allow multiple modes of processing, whereas the hydroxyapatite binding domain VTKHLNQISQSY (VTK), provided control over osteogenesis. The VTK domain was fused either to the N-, C- or both terminals of the spider silk domain to understand the effect of position on material properties and mineralization. The addition of the VTK domain to silk did not affect the physical properties of the silk recombinant constructs, but it had a critical role in the induction of biomineralization. When the VTK domain was placed on both the C- and N-termini the formation of crystalline hydroxyapatite was significantly increased. In addition, all of the recombinant proteins in film format supported the growth and proliferation of human mesenchymal stem cells (hMSCs). Importantly, the presence of the VTK domain enhanced osteoinductive properties up to 3-fold compared to the control (silk alone without VTK). Therefore, silk-VTK fusion proteins have been shown suitable for mineralization and functionalization for specific biomedical applications. Organic-inorganic interfaces are integral to biomaterial functions in many areas of repair and regeneration. Several protein polymers have been investigated for this purpose. Despite their success the limited options to fine-tune their material properties, degradation patterns and functionalize them for each specific biomedical application limits their application. Various studies have shown that the biological performance of such proteins can be improved by genetic engineering. The present study provides data

  9. Osteoinductive peptide-functionalized nanofibers with highly ordered structure as biomimetic scaffolds for bone tissue engineering.

    Science.gov (United States)

    Gao, Xiang; Zhang, Xiaohong; Song, Jinlin; Xu, Xiao; Xu, Anxiu; Wang, Mengke; Xie, Bingwu; Huang, Enyi; Deng, Feng; Wei, Shicheng

    2015-01-01

    The construction of functional biomimetic scaffolds that recapitulate the topographical and biochemical features of bone tissue extracellular matrix is now of topical interest in bone tissue engineering. In this study, a novel surface-functionalized electrospun polycaprolactone (PCL) nanofiber scaffold with highly ordered structure was developed to simulate the critical features of native bone tissue via a single step of catechol chemistry. Specially, under slightly alkaline aqueous solution, polydopamine (pDA) was coated on the surface of aligned PCL nanofibers after electrospinning, followed by covalent immobilization of bone morphogenetic protein-7-derived peptides onto the pDA-coated nanofiber surface. Contact angle measurement, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the presence of pDA and peptides on PCL nanofiber surface. Our results demonstrated that surface modification with osteoinductive peptides could improve cytocompatibility of nanofibers in terms of cell adhesion, spreading, and proliferation. Most importantly, Alizarin Red S staining, quantitative real-time polymerase chain reaction, immunostaining, and Western blot revealed that human mesenchymal stem cells cultured on aligned nanofibers with osteoinductive peptides exhibited enhanced osteogenic differentiation potential than cells on randomly oriented nanofibers. Furthermore, the aligned nanofibers with osteoinductive peptides could direct osteogenic differentiation of human mesenchymal stem cells even in the absence of osteoinducting factors, suggesting superior osteogenic efficacy of biomimetic design that combines the advantages of osteoinductive peptide signal and highly ordered nanofibers on cell fate decision. The presented peptide-decorated bone-mimic nanofiber scaffolds hold a promising potential in the context of bone tissue engineering.

  10. Functionalization of deproteinized bovine bone with a coating-incorporated depot of BMP-2 renders the material efficiently osteoinductive and suppresses foreign-body reactivity.

    Science.gov (United States)

    Wu, Gang; Hunziker, Ernst B; Zheng, Yuanna; Wismeijer, Daniel; Liu, Yuelian

    2011-12-01

    The repair of critical-sized bony defects remains a challenge in the fields of implantology, maxillofacial surgery and orthopaedics. As an alternative bone-defect filler to autologous bone grafts, deproteinized bovine bone (DBB) is highly osteoconductive and clinically now widely used. However, this product suffers from the disadvantage of not being intrinsically osteoinductive. In the present study, this property was conferred by coating DBB with a layer of calcium phosphate into which bone morphogenetic protein 2 (BMP-2) was incorporated. Granules of DBB bearing a coating-incorporated depot of BMP-2--together with the appropriate controls (DBB bearing a coating but no BMP-2; uncoated DBB bearing adsorbed BMP-2; uncoated DBB bearing no BMP-2)--were implanted subcutaneously in rats. Five weeks later, the implants were withdrawn for a histomorphometric analysis of the volume densities of (i) bone, (ii) bone marrow, (iii) foreign-body giant cells and (iv) fibrous capsular tissue. Parameters (i) and (ii) were highest, whilst parameters (iii) and (iv) were lowest in association with DBB bearing a coating-incorporated depot of BMP-2. Hence, this mode of functionalization not only confers DBB with the property of osteoinductivity but also improves its biocompatibility--thus dually enhancing its clinical potential in the repair of bony defects. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Biological properties of biphasic tricalcium phosphate bioceramics/calcium sulfate bone cement porous three-dimensional scaffolds%双相钙磷生物陶瓷/硫酸钙骨水泥多孔三维支架的生物性能

    Institute of Scientific and Technical Information of China (English)

    谭迎赟; 白石; 廖运茂

    2014-01-01

    背景:随着组织工程技术的发展,多孔生物陶瓷被越来越多的运用到骨缺损的修复中,当前的研究主要集中在这种生物陶瓷的合成及其各项性能的评价。  目的:研究一种新型骨水泥的制备方法并测定其理化性能及与成骨细胞的生物相容性。  方法:共沉淀法制备双相钙磷生物陶瓷粉体,利用胶体团聚成颗粒,烧结后得到颗粒状、多孔羟基磷灰石/磷酸三钙生物陶瓷,并按不同比例与高纯度医用半水硫酸钙混合制备钙磷陶瓷/硫酸钙骨水泥。  结果与结论:X 射线衍射证实合成物质为双相钙磷陶瓷,颗粒状双相钙磷陶瓷具有多孔网状结构,骨水泥在3 min内保持可塑状态,固化时间为15 min,固化温度为36.5℃,压缩强度最高为5.82 MPa,MTT毒性级为0级,成骨细胞在材料表面生长良好。%BACKGROUND:With the development of tissue engineering, porous bioceramics are more and more used to repair bone defects. Current research focuses on the biological synthesis of this bioceramics and its performance evaluation. OBJECTIVE:To discuss the preparation of a new kind of bone cement and to determine its physicochemical properties and biocompatibility with osteoblasts. METHODS:Biphasic tricalcium phosphate powders were prepared using co-precipitation method. The powder was turned into granular stuff by arabic gum. After sintering, porous hydroxyapatite/tricalcium phosphate bioceramics were harvested, and then mixed with alpha-hemihydrate to prepare the bone cement. RESULTS AND CONCLUSION:X-ray diffraction confirmed that the synthetic substance was a kind of biphasic calcium phosphate ceramic having a porous structure. The bone cement could be in the plastic state within 3 minutes. The curing time was 15 minutes, and the curing temperature was 36.5℃. The maximum compression strength was 5.82 MPa, and the MTT toxicity was level 0. Osteoblasts could grew wel on the

  12. Biomaterials with Antibacterial and Osteoinductive Properties to Repair Infected Bone Defects.

    Science.gov (United States)

    Lu, Haiping; Liu, Yi; Guo, Jing; Wu, Huiling; Wang, Jingxiao; Wu, Gang

    2016-03-03

    The repair of infected bone defects is still challenging in the fields of orthopedics, oral implantology and maxillofacial surgery. In these cases, the self-healing capacity of bone tissue can be significantly compromised by the large size of bone defects and the potential/active bacterial activity. Infected bone defects are conventionally treated by a systemic/local administration of antibiotics to control infection and a subsequent implantation of bone grafts, such as autografts and allografts. However, these treatment options are time-consuming and usually yield less optimal efficacy. To approach these problems, novel biomaterials with both antibacterial and osteoinductive properties have been developed. The antibacterial property can be conferred by antibiotics and other novel antibacterial biomaterials, such as silver nanoparticles. Bone morphogenetic proteins are used to functionalize the biomaterials with a potent osteoinductive property. By manipulating the carrying modes and release kinetics, these biomaterials are optimized to maximize their antibacterial and osteoinductive functions with minimized cytotoxicity. The findings, in the past decade, have shown a very promising application potential of the novel biomaterials with the dual functions in treating infected bone defects. In this review, we will summarize the current knowledge of novel biomaterials with both antibacterial and osteoinductive properties.

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

    Science.gov (United States)

    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. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Biomaterials with Antibacterial and Osteoinductive Properties to Repair Infected Bone Defects

    Directory of Open Access Journals (Sweden)

    Haiping Lu

    2016-03-01

    Full Text Available The repair of infected bone defects is still challenging in the fields of orthopedics, oral implantology and maxillofacial surgery. In these cases, the self-healing capacity of bone tissue can be significantly compromised by the large size of bone defects and the potential/active bacterial activity. Infected bone defects are conventionally treated by a systemic/local administration of antibiotics to control infection and a subsequent implantation of bone grafts, such as autografts and allografts. However, these treatment options are time-consuming and usually yield less optimal efficacy. To approach these problems, novel biomaterials with both antibacterial and osteoinductive properties have been developed. The antibacterial property can be conferred by antibiotics and other novel antibacterial biomaterials, such as silver nanoparticles. Bone morphogenetic proteins are used to functionalize the biomaterials with a potent osteoinductive property. By manipulating the carrying modes and release kinetics, these biomaterials are optimized to maximize their antibacterial and osteoinductive functions with minimized cytotoxicity. The findings, in the past decade, have shown a very promising application potential of the novel biomaterials with the dual functions in treating infected bone defects. In this review, we will summarize the current knowledge of novel biomaterials with both antibacterial and osteoinductive properties.

  15. In vivo performance of microstructured calcium phosphate formulated in novel water-free carriers

    NARCIS (Netherlands)

    Davison, N.L.; Yuan, Huipin; de Bruijn, Joost Dick; Barrere-de Groot, F.YF.

    2012-01-01

    Osteoinductive calcium phosphate (CaP) ceramics can be combined with polymeric carriers to make shapeable bone substitutes as an alternative to autologous bone; however, carriers containing water may degrade the ceramic surface microstructure, which is crucial to bone formation. In this study five

  16. Acute Biphasic Effects of Ayahuasca.

    Science.gov (United States)

    Schenberg, Eduardo Ekman; Alexandre, João Felipe Morel; Filev, Renato; Cravo, Andre Mascioli; Sato, João Ricardo; Muthukumaraswamy, Suresh D; Yonamine, Maurício; Waguespack, Marian; Lomnicka, Izabela; Barker, Steven A; da Silveira, Dartiu Xavier

    2015-01-01

    Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca's chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.

  17. Acute Biphasic Effects of Ayahuasca.

    Directory of Open Access Journals (Sweden)

    Eduardo Ekman Schenberg

    Full Text Available Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca's chemical compounds, mostly N,N-dimethyltryptamine (DMT, harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.

  18. In vitro study on biomineralization of biphasic calcium phosphate ...

    Indian Academy of Sciences (India)

    Chitosan, a product obtained by removal of acetyl group from chitin, is the second .... range using Nicolet Impact 400 Fourier transform infrared spectrophotometer using .... trum shows BCP is intact without disintegration. It reveals the presence ...

  19. Thermal stability of hydroxyapatite in biphasic calcium phosphate ceramics

    CSIR Research Space (South Africa)

    Nilen, RWN

    2008-04-01

    Full Text Available temperatures greater than 1125 C. Because the HA/b-TCP ratio dominantly determines the rate and extent of BCP resorption in vivo, the possible thermal decomposition of HA during BCP synthesis must be considered, particularly if high temperature treatments...

  20. Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak

    Science.gov (United States)

    Sankaranarayanan, Rajiv; Li, Yatong; Greensmith, David J.; Eisner, David A.

    2016-01-01

    Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay.In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase.Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient.Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine.Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient. Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the

  1. Ethylene oxide gas sterilization does not reduce the osteoinductive potential of demineralized bone in rats

    DEFF Research Database (Denmark)

    Solheim, E; Pinholt, E M; Bang, G

    1995-01-01

    It has been shown that different sterilization procedures of demineralized bone may influence its osteoinductive properties. The aim of this study was to evaluate the effect of ethylene oxide sterilization for 1, 3, and 6 hours on the osteoinductive potential of allogeneic demineralized bone...... implanted heterotopically in rats. Sixty male Wistar rats were randomly assigned to one of four groups, A through D, and four demineralized bone chips (2.8 mg) were implanted in a pouch created between the right oblique abdominal muscles in each animal. In Group A, the demineralized bone was implanted...... without prior sterilization of the material, whereas the demineralized bone implanted in Groups B, C, and D had been sterilized in ethylene oxide gas for 1, 3, or 6 hours, respectively, and aerated for 48 hours. At 4 weeks postoperatively, bone formation was evaluated quantitatively by strontium 85 uptake...

  2. Alveolar ridge augmentation in rats by combined hydroxylapatite and osteoinductive material

    DEFF Research Database (Denmark)

    Pinholt, E M; Bang, G; Haanaes, H R

    1991-01-01

    , lyophilized dentin or bone and implanted subperiosteally for alveolar ridge augmentation purposes and heterotopically in the abdominal muscles in rats. Light microscopic evaluation revealed that HA was surrounded by fibrous connective tissue containing foreign body giant cells and it had neither...... an osteoinductive nor an osteoconductive effect. The newly formed bone induced from the implanted allogenic, demineralized, lyophilized dentin or bone was never found in close contact with the HA and did not incorporate the implant....

  3. Effect of ethylene oxide sterilization on the osteoinductivity of demineralized allograft bone powder

    International Nuclear Information System (INIS)

    Hamid Reza Aghayan; Babak Arjmand; Mehdi Golestani; Farokh Tirgari

    2008-01-01

    Full text: Ethylene oxide has been widely used for secondary sterilization of bone allograft to reduce the risk of infection and associated complications. In this study we investigate the effects of ethylene oxide gas sterilization on the osteoinductivity of demineralized bone Powder. Eighteen rats received two separate implants consisting of 30 mg aseptically prepared and 30 mg ethylene oxide-sterilized demineralized bone powder. The demineralized bone powder from each group was placed into two separate muscle pouch created in the paravertebral muscles of each rat. After 4 weeks each implantation site was removed with 0.5 cm normal tissue around the implant. Histological examination was done to determine the presence or absence of osteoinduction. All except one of eighteen aseptically prepared demineralized bone powder sites histologically contained new bone elements (94.4%) and fourteen (77.7%) of ethylene oxide sterilized demineralized bone powder sites showed evidence of new bone elements (p>0.05). There is no significant difference in osteoblast formation in two groups. We concluded that ethylene oxide sterilization in 42 degree C did not significantly reduce the osteoinductivity of demineralized bone powder. So ethylene oxide can be considered as a suitable but not perfect method for secondary sterilization of demineralized bone powder. (Author)

  4. Polyglutamate directed coupling of bioactive peptides for the delivery of osteoinductive signals on allograft bone

    Science.gov (United States)

    Culpepper, Bonnie K.; Bonvallet, Paul P.; Reddy, Michael S.; Ponnazhagan, Selvarangan; Bellis, Susan L.

    2012-01-01

    Allograft bone is commonly used as an alternative to autograft, however allograft lacks many osteoinductive factors present in autologous bone due to processing. In this study, we investigated a method to reconstitute allograft with osteoregenerative factors. Specifically, an osteoinductive peptide from collagen I, DGEA, was engineered to express a heptaglutamate (E7) domain, which binds the hydroxyapatite within bone mineral. Addition of E7 to DGEA resulted in 9× greater peptide loading on allograft, and significantly greater retention after a 5-day interval with extensive washing. When factoring together greater initial loading and retention, the E7 domain directed a 45-fold enhancement of peptide density on the allograft surface. Peptide-coated allograft was also implanted subcutaneously into rats and it was found that E7DGEA was retained in vivo for at least 3 months. Interestingly, E7DGEA peptides injected intravenously accumulated within bone tissue, implicating a potential role for E7 domains in drug delivery to bone. Finally, we determined that, as with DGEA, the E7 modification enhanced coupling of a bioactive BMP2-derived peptide on allograft. These results suggest that E7 domains are useful for coupling many types of bone-regenerative molecules to the surface of allograft to reintroduce osteoinductive signals and potentially advance allograft treatments. PMID:23182349

  5. Biphasic products of dicalcium phosphate-rich cement with injectability and nondispersibility

    International Nuclear Information System (INIS)

    Ko, Chia-Ling; Chen, Jian-Chih; Hung, Chun-Cheng; Wang, Jen-Chyan; Tien, Yin-Chun; Chen, Wen-Cheng

    2014-01-01

    In this study, a calcium phosphate cement was developed using tetracalcium phosphate and surface-modified dicalcium phosphate anhydrous (DCPA). This developed injectable bone graft substitute can be molded to the shape of the bone cavity and set in situ through the piping system that has an adequate mechanical strength, non-dispersibility, and biocompatibility. The materials were based on the modified DCPA compositions of calcium phosphate cement (CPC), where the phase ratio of the surface-modified DCPA is higher than that of the conventional CPC for forming dicalcium phosphate (DCP)-rich cement. The composition and morphology of several calcium phosphate cement specimens during setting were analyzed via X-ray diffractometry and transmission electron microscopy coupled with an energy dispersive spectroscopy system. The compressive strength of DCP-rich CPCs was greater than 30 MPa after 24 h of immersion in vitro. The reaction of the CPCs produced steady final biphasic products of DCPs with apatite. The composites of calcium phosphate cements derived from tetracalcium phosphate mixed with surface-modified DCPA exhibited excellent mechanical properties, injectability, and interlocking forces between particles, and they also featured nondispersive behavior when immersed in a physiological solution. - Highlights: • Bone cement precursor with nanocrystals is characterized. • DCP-rich CPCs with nanocrystals exhibited biphasic product phases. • Nanocrystals in cement significantly affected the interlocking ability. • Nanocrystals in cement exhibited higher strength and anti-dispersion. • DCP-rich CPCs increase the potential of bioresorption after reaction

  6. Osteoinductive peptide-functionalized nanofibers with highly ordered structure as biomimetic scaffolds for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Gao X

    2015-11-01

    Full Text Available Xiang Gao,1,2,* Xiaohong Zhang,3,* Jinlin Song,1,2 Xiao Xu,4 Anxiu Xu,1 Mengke Wang,4 Bingwu Xie,1 Enyi Huang,2 Feng Deng,1,2 Shicheng Wei2–41College of Stomatology, 2Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, 3Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, 4Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, Peking University School and Hospital of Stomatology, Beijing, People’s Republic of China*These authors contributed equally to this workAbstract: The construction of functional biomimetic scaffolds that recapitulate the topographical and biochemical features of bone tissue extracellular matrix is now of topical interest in bone tissue engineering. In this study, a novel surface-functionalized electrospun polycaprolactone (PCL nanofiber scaffold with highly ordered structure was developed to simulate the critical features of native bone tissue via a single step of catechol chemistry. Specially, under slightly alkaline aqueous solution, polydopamine (pDA was coated on the surface of aligned PCL nanofibers after electrospinning, followed by covalent immobilization of bone morphogenetic protein-7-derived peptides onto the pDA-coated nanofiber surface. Contact angle measurement, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the presence of pDA and peptides on PCL nanofiber surface. Our results demonstrated that surface modification with osteoinductive peptides could improve cytocompatibility of nanofibers in terms of cell adhesion, spreading, and proliferation. Most importantly, Alizarin Red S staining, quantitative real-time polymerase chain reaction, immunostaining, and Western blot revealed that human mesenchymal stem cells cultured on aligned nanofibers with osteoinductive peptides exhibited enhanced osteogenic differentiation potential than

  7. Mediated water electrolysis in biphasic systems.

    Science.gov (United States)

    Scanlon, Micheál D; Peljo, Pekka; Rivier, Lucie; Vrubel, Heron; Girault, Hubert H

    2017-08-30

    The concept of efficient electrolysis by linking photoelectrochemical biphasic H 2 evolution and water oxidation processes in the cathodic and anodic compartments of an H-cell, respectively, is introduced. Overpotentials at the cathode and anode are minimised by incorporating light-driven elements into both biphasic reactions. The concepts viability is demonstrated by electrochemical H 2 production from water splitting utilising a polarised water-organic interface in the cathodic compartment of a prototype H-cell. At the cathode the reduction of decamethylferrocenium cations ([Cp 2 *Fe (III) ] + ) to neutral decamethylferrocene (Cp 2 *Fe (II) ) in 1,2-dichloroethane (DCE) solvent takes place at the solid electrode/oil interface. This electron transfer process induces the ion transfer of a proton across the immiscible water/oil interface to maintain electroneutrality in the oil phase. The oil-solubilised proton immediately reacts with Cp 2 *Fe (II) to form the corresponding hydride species, [Cp 2 *Fe (IV) (H)] + . Subsequently, [Cp 2 *Fe (IV) (H)] + spontaneously undergoes a chemical reaction in the oil phase to evolve hydrogen gas (H 2 ) and regenerate [Cp 2 *Fe (III) ] + , whereupon this catalytic Electrochemical, Chemical, Chemical (ECC') cycle is repeated. During biphasic electrolysis, the stability and recyclability of the [Cp 2 *Fe (III) ] + /Cp 2 *Fe (II) redox couple were confirmed by chronoamperometric measurements and, furthermore, the steady-state concentration of [Cp 2 *Fe (III) ] + monitored in situ by UV/vis spectroscopy. Post-biphasic electrolysis, the presence of H 2 in the headspace of the cathodic compartment was established by sampling with gas chromatography. The rate of the biphasic hydrogen evolution reaction (HER) was enhanced by redox electrocatalysis in the presence of floating catalytic molybdenum carbide (Mo 2 C) microparticles at the immiscible water/oil interface. The use of a superhydrophobic organic electrolyte salt was critical to

  8. Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

    Science.gov (United States)

    Ng, Choong Hey; Yang, Kun-Lin

    2016-01-01

    Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Characterization and in vitro evaluation of biphasic α-tricalcium phosphate/β-tricalcium phosphate cement

    Energy Technology Data Exchange (ETDEWEB)

    Arahira, Takaaki; Maruta, Michito, E-mail: maruta@college.fdcnet.ac.jp; Matsuya, Shigeki

    2017-05-01

    Biphasic calcium phosphate consisting of hydroxyapatite (HA) and β-tricalcium phosphate(β-TCP) is an excellent bone substitute with controllable bioresorbability. Fabrication of biphasic calcium phosphate with self-setting ability is expected to enhance its potential application as bone substitute. In this study, mixtures of α-TCP and β-TCP with various compositions were prepared through α-β phase transition of α-TCP powder at 1000 °C for various periods. These powders were mixed with 0.25 M Na{sub 2}HPO{sub 4} at a P/L ratio of 2, and then hardened at 37 °C at 100% RH for up to 24 h. Material properties of biphasic HA/β-TCP cement with different α-TCP/β-TCP composition were characterized. These cements were also evaluated with respect to cell response in vitro using MC3T3-E1 cell lines. In conclusion, mechanical and biological properties of HA/β-TCP cement could be controlled by changing the heat treatment time of α-TCP powder at 1000 °C. In vitro results indicated that cell proliferation and ALP activity increased with increase β-TCP content. - Highlights: • We could fabricate biphasic HA/β-TCP cements using heat treated α-TCP powder. • It is easy to control the ratio of α-TCP to β-TCP changing the heat treatment time up to 48 h. • Both cell number and ALP activity increased with increase in β-TCP content. • In vitro results showed that β-TCP has superior cell affinity to HA.

  10. Metal separations using aqueous biphasic partitioning systems

    International Nuclear Information System (INIS)

    Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.; Vojta, Y.; Gartelmann, J.; Mego, W.

    1996-01-01

    Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation

  11. Biphase sinusoidal oscillator based on negative resistor.

    Science.gov (United States)

    Bayard, Jean

    2010-06-01

    This paper describes a biphase sinusoidal generator which provides two signals: v(ref)=V(M) sin(omegat) and v(out)=V(M) sin(omegat+DeltaPhi), where DeltaPhi is in the range 0, pi/2 or -pi/2, 0 and is not dependent on the frequency value. It is based on a negative resistor and it requires very few components. SPICE simulations and measurements on an experimental setup confirm the theoretical analysis.

  12. Effect of storage on osteoinductive properties of demineralized bone in rats

    DEFF Research Database (Denmark)

    Pinholt, E M; Solheim, E

    1994-01-01

    A requirement for the clinical use of demineralized bone is the possibility of storing the material without loss of its osteoinductive properties. Seventy-five 8-week-old male Wistar rats were randomly assigned to one of five groups of 15 rats each. Lyophilized demineralized allogeneic bone...... was prepared and implanted in the abdominal muscle either without prior storage (control group) or after storage for 9 or 14 months at -70 degrees C or 4 degrees C (four experimental groups). Bone formation in the implants was evaluated quantitatively 4 weeks postoperatively by measuring the strontium 85...

  13. Fabrication of nano structural biphasic materials from phosphogypsum waste and their in vitro applications

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Khaled R., E-mail: Kh_rezk966@yahoo.com [Biomaterials Department, National Research Centre, Dokki, Cairo (Egypt); Mousa, Sahar M. [Chemistry Department, Science and Art College, King Abdulaziz University, Rabigh Campus, P.O. Box 344, 21911 Rabigh (Saudi Arabia); Inorganic Chemistry Department, National Research Centre, Dokki, P.O. Box 12622, 11787 Cairo (Egypt); El Bassyouni, Gehan T. [Biomaterials Department, National Research Centre, Dokki, Cairo (Egypt); Medical Physics Department, College of Medicine, Taif University (Saudi Arabia)

    2014-02-01

    Graphical abstract: (a) Schema of the process, (b) TEM of nano particles of biphasic materials and (c) SEM of post-immersion. - Highlights: • Ratio of HA and β-TCP phases were controlled by thermal treatment. • HA partially decomposed into β-TCP with other bioactive phases. • Calcined HA at 900 °C is the best for the bioactivity behavior. - Abstract: In this study, a novel process of preparing biphasic calcium phosphate (BCP) is proposed. Also its bioactivity for the utilization of the prepared BCP as a biomaterial is studied. A mixture of calcium hydroxyapatite (HAP) and tricalcium phosphate (β-TCP) could be obtained by thermal treatment of HAP which was previously prepared from phosphogypsum (PG) waste. The chemical and phase composition, morphology and particle size of prepared samples was characterized by X-ray diffraction (XRD), Infrared spectroscopy (IR), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The bioactivity was investigated by soaking of the calcined samples in simulated body fluid (SBF). Results confirmed that the calcination temperatures played an important role in the formation of calcium phosphate (CP) materials. XRD results indicated that HAP was partially decomposed into β-TCP. The in vitro data confirmed that the calcined HAP forming BCP besides other phases such as pyrophosphate and silica are bioactive materials. Therefore, BCP will be used as good biomaterials for medical applications.

  14. Charge-balanced biphasic electrical stimulation inhibits neurite extension of spiral ganglion neurons.

    Science.gov (United States)

    Shen, Na; Liang, Qiong; Liu, Yuehong; Lai, Bin; Li, Wen; Wang, Zhengmin; Li, Shufeng

    2016-06-15

    Intracochlear application of exogenous or transgenic neurotrophins, such as neurotrophin-3 (NT-3) and brain derived neurotrophic factor (BDNF), could promote the resprouting of spiral ganglion neuron (SGN) neurites in deafened animals. These resprouting neurites might reduce the gap between cochlear implant electrodes and their targeting SGNs, allowing for an improvement of spatial resolution of electrical stimulation. This study is to investigate the impact of electrical stimulation employed in CI on the extension of resprouting SGN neurites. We established an in vitro model including the devices delivering charge-balanced biphasic electrical stimulation, and spiral ganglion (SG) dissociated culture treated with BDNF and NT-3. After electrical stimulation with varying durations and intensities, we quantified neurite lengths and Schwann cell densities in SG cultures. Stimulations that were greater than 50μA or longer than 8h significantly decreased SG neurite length. Schwann cell density under 100μA electrical stimulation for 48h was significantly lower compared to that in non-stimulated group. These electrical stimulation-induced decreases of neurite extension and Schwann cell density were attenuated by various types of voltage-dependent calcium channel (VDCC) blockers, or completely prevented by their combination, cadmium or calcium-free medium. Our study suggested that charge-balanced biphasic electrical stimulation inhibited the extension of resprouting SGN neurites and decreased Schwann cell density in vitro. Calcium influx through multiple types of VDCCs was involved in the electrical stimulation-induced inhibition. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Incorporation of sol–gel bioactive glass into PLGA improves mechanical properties and bioactivity of composite scaffolds and results in their osteoinductive properties

    International Nuclear Information System (INIS)

    Filipowska, J; Tylko, G; Osyczka, A M; Pawlik, J; Cholewa-Kowalska, K; Laczka, M; Pamula, E; Niedzwiedzki, L; Szuta, M

    2014-01-01

    In this study, 3D porous bioactive composite scaffolds were produced and evaluated for their physico-chemical and biological properties. Polymer poly-L-lactide-co-glycolide (PLGA) matrix scaffolds were modified with sol–gel-derived bioactive glasses (SBGs) of CaO–SiO 2 –P 2 O 5 systems. We hypothesized that SBG incorporation into PLGA matrix would improve the chemical and biological activity of composite materials as well as their mechanical properties. We applied two bioactive glasses, designated as S2 or A2, differing in the content of SiO 2 and CaO (i.e. 80 mol% SiO 2 , 16 mol% CaO for S2 and 40 mol% SiO 2 , 52 mol% CaO for A2). The composites were characterized for their porosity, bioactivity, microstructure and mechanical properties. The osteoinductive properties of these composites were evaluated in human bone marrow stromal cell (hBMSC) cultures grown in either standard growth medium or treated with recombinant human bone morphogenetic protein-2 (rhBMP-2) or dexamethasone (Dex). After incubation in simulated body fluid, calcium phosphate precipitates formed inside the pores of both A2-PLGA and S2-PLGA scaffolds. The compressive strength of the latter was increased slightly compared to PLGA. Both composites promoted superior hBMSC attachment to the material surface and stimulated the expression of several osteogenic markers in hBMSC compared to cells grown on unmodified PLGA. There were also marked differences in the response of hBMSC to composite scaffolds, depending on chemical compositions of the scaffolds and culture treatments. Compared to silica-rich S2-PLGA, hBMSC grown on calcium-rich A2-PLGA were overall less responsive to rhBMP-2 or Dex and the osteoinductive properties of these A2-PLGA scaffolds seemed partially dependent on their ability to induce BMP signaling in untreated hBMSC. Thus, beyond the ability of currently studied composites to enhance hBMSC osteogenesis, it may become possible to modulate the osteogenic response of h

  16. A preliminary study in osteoinduction by a nano-crystalline hydroxyapatite in the mini pig

    Directory of Open Access Journals (Sweden)

    Werner Götz

    2010-04-01

    Full Text Available To test the probable osteoinductive properties of NanoBone®, a new highly non-sintered porous nano-crystallinehydroxylapatite bone substitute embedded into a silica gel matrix, granules were implanted subcutaneously and intramuscularlyinto the back region of 18 mini pigs. After periods of 5 and 10 weeks as well as 4 and 8 months, implantation siteswere investigated using histological and histomorphometric procedures. Signs of early osteogenesis could already be detectedafter 5 weeks. The later periods were characterized by increasing membranous osteogenesis in and around the granulesleading to the formation of bone-like structures showing periosteal and tendon-like structures with bone marrow and focalchondrogenesis. Bone formation was better in the subcutaneous than in the intramuscular implantation sites. This ectopicosteogenesis is discussed with regard to the nanoporosity and microporosity of the material, physico-chemical interactionsat its surface, the differentiation of osteoblasts, the role of angiogenesis and the probable involvement of growth factors. Theresults of this preliminary study indicate that this biomaterial has osteoinductive potential and induces the formation of bonestructures, mainly in subcutaneous adipose tissue in the pig.

  17. Effect of gamma irradiation sterilization on the osteoinductive capacity of demineralized bone powder

    International Nuclear Information System (INIS)

    Babak Arjmand; Hamid Reza Aghayan; Mehdi Golestani; Farid Azmoudeh Ardalan

    2008-01-01

    Full text: Gamma irradiation is a well known method for secondary sterilization of bone allograft before clinical use to reduce the risk of infections and complications. The current study evaluated the effect of gamma irradiation on the osteoinductive capability of human demineralized bone powder using a rat model. Twenty rats received two separate implants consisting of 30 mg aseptically-harvested and 30 mg gamma irradiated demineralized bone powder. The implants from each group were placed into two separate muscle pouch in the paravertebral muscles of each rat. All 20 rats were euthanized after 4 weeks and each implantation site was removed with 0.5 cm normal tissue around the implant. Histological examination was done to determine the presence or absence of new bone, cartilage and bone marrow element. All except one of 20 aseptically-harvested demineralized bone powder sites histologically contained new bone elements (95%) and six (30%) of 20 gamma irradiated demineralized bone powder sites showed evidence of new bone elements. There was significant difference between two groups (p<0.05). The results of this study indicate that gamma irradiation reduces osteoinductive properties of demineralized bone powder. But because of its availability and low cost it is widely used for secondary sterilization of bone allografts. (Author)

  18. A preliminary study in osteoinduction by a nano-crystalline hydroxyapatite in the mini pig.

    Directory of Open Access Journals (Sweden)

    Karsten K H Gundlach

    2011-04-01

    Full Text Available To test the probable osteoinductive properties of NanoBone, a new highly non-sintered porous nano-crystalline hydroxylapatite bone substitute embedded into a silica gel matrix, granules were implanted subcutaneously and intramuscularly into the back region of 18 mini pigs. After periods of 5 and 10 weeks as well as 4 and 8 months, implantation sites were investigated using histological and histomorphometric procedures. Signs of early osteogenesis could already be detected after 5 weeks. The later periods were characterized by increasing membranous osteogenesis in and around the granules leading to the formation of bone-like structures showing periosteal and tendon-like structures with bone marrow and focal chondrogenesis. Bone formation was better in the subcutaneous than in the intramuscular implantation sites. This ectopic osteogenesis is discussed with regard to the nanoporosity and microporosity of the material, physico-chemical interactions at its surface, the differentiation of osteoblasts, the role of angiogenesis and the probable involvement of growth factors. The results of this preliminary study indicate that this biomaterial has osteoinductive potential and induces the formation of bone structures, mainly in subcutaneous adipose tissue in the pig.

  19. A preliminary study in osteoinduction by a nano-crystalline hydroxyapatite in the mini pig.

    Science.gov (United States)

    Götz, Werner; Lenz, Solvig; Reichert, Christoph; Henkel, Kai-Olaf; Bienengräber, Volker; Pernicka, Laura; Gundlach, Karsten K H; Gredes, Tomasz; Gerber, Thomas; Gedrange, Tomasz; Heinemann, Friedhelm

    2010-12-01

    To test the probable osteoinductive properties of NanoBone, a new highly non-sintered porous nano-crystalline hydroxylapatite bone substitute embedded into a silica gel matrix, granules were implanted subcutaneously and intramuscularly into the back region of 18 mini pigs. After periods of 5 and 10 weeks as well as 4 and 8 months, implantation sites were investigated using histological and histomorphometric procedures. Signs of early osteogenesis could already be detected after 5 weeks. The later periods were characterized by increasing membranous osteogenesis in and around the granules leading to the formation of bone-like structures showing periosteal and tendon-like structures with bone marrow and focal chondrogenesis. Bone formation was better in the subcutaneous than in the intramuscular implantation sites. This ectopic osteogenesis is discussed with regard to the nanoporosity and microporosity of the material, physico-chemical interactions at its surface, the differentiation of osteoblasts, the role of angiogenesis and the probable involvement of growth factors. The results of this preliminary study indicate that this biomaterial has osteoinductive potential and induces the formation of bone structures, mainly in subcutaneous adipose tissue in the pig.

  20. Small intestinal submucosa: A potential osteoconductive and osteoinductive biomaterial for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mei [Zhejiang Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211 (China); Ningbo Medical Science Research Institute, Ningbo, Zhejiang 315020 (China); Zhang, Chi; Cheng, Mengjie; Gu, Qiaoqiao [Zhejiang Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211 (China); Zhao, Jiyuan, E-mail: zhaojiyuan@nbu.edu.cn [Zhejiang Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211 (China)

    2017-06-01

    SIS is an acellular, naturally occurring collagenous extracellular matrix (ECM) material with various bioactive factors, which broadly applied in tissue engineering in clinic. Several studies have applied SIS in bone tissue engineering to enhance bone regeneration in animal models. However, the mechanism was rarely investigated. The aim of the current study was to investigate the osteoconductivity and osteoinductivity of SIS scaffold to bone regeneration systematically and the potential mechanism. Our results showed that SIS scaffold with excellent biocompatibility was beneficial for cell attachment, proliferation, migration and osteogenic differentiation of various cells contributing to bone repair. In mouse calvarial defect model, bone regeneration was significantly enhanced in the defects implanted with SIS scaffolds, along with the up-regulation of BMP-2 and CD31 expression. Accordingly, ID-1, the downstream target gene of BMPs, was increased in BMSCs cultured on SIS scaffolds. The results of this study suggest that SIS scaffold is a potential osteoconductive and osteoinductive biomaterial which plays multiple roles to various cells during process of bone regeneration. - Highlights: • SIS facilitates cell adhesion of BMSCs, osteoblasts and fibroblasts. • SIS promotes cell proliferation of osteoblasts and fibroblasts. • SIS promotes osteogenic differentiation of BMSCs and osteoblasts via BMP-2 pathway. • Synergistic effects of SIS to multiple cells enhance bone regeneration in vivo.

  1. Small intestinal submucosa: A potential osteoconductive and osteoinductive biomaterial for bone tissue engineering

    International Nuclear Information System (INIS)

    Li, Mei; Zhang, Chi; Cheng, Mengjie; Gu, Qiaoqiao; Zhao, Jiyuan

    2017-01-01

    SIS is an acellular, naturally occurring collagenous extracellular matrix (ECM) material with various bioactive factors, which broadly applied in tissue engineering in clinic. Several studies have applied SIS in bone tissue engineering to enhance bone regeneration in animal models. However, the mechanism was rarely investigated. The aim of the current study was to investigate the osteoconductivity and osteoinductivity of SIS scaffold to bone regeneration systematically and the potential mechanism. Our results showed that SIS scaffold with excellent biocompatibility was beneficial for cell attachment, proliferation, migration and osteogenic differentiation of various cells contributing to bone repair. In mouse calvarial defect model, bone regeneration was significantly enhanced in the defects implanted with SIS scaffolds, along with the up-regulation of BMP-2 and CD31 expression. Accordingly, ID-1, the downstream target gene of BMPs, was increased in BMSCs cultured on SIS scaffolds. The results of this study suggest that SIS scaffold is a potential osteoconductive and osteoinductive biomaterial which plays multiple roles to various cells during process of bone regeneration. - Highlights: • SIS facilitates cell adhesion of BMSCs, osteoblasts and fibroblasts. • SIS promotes cell proliferation of osteoblasts and fibroblasts. • SIS promotes osteogenic differentiation of BMSCs and osteoblasts via BMP-2 pathway. • Synergistic effects of SIS to multiple cells enhance bone regeneration in vivo.

  2. Biphasic influence of dexamethasone exposure on embryonic vertebrate skeleton development

    International Nuclear Information System (INIS)

    Cheng, Xin; Chen, Jian-long; Ma, Zheng-lai; Zhang, Zhao-long; Lv, Shun; Mai, Dong-mei; Liu, Jia-jia; Chuai, Manli; Lee, Kenneth Ka Ho; Wan, Chao; Yang, Xuesong

    2014-01-01

    Dexamethasone (Dex) has anti-inflammatory and immunomodulatory properties against many conditions. There is a potential teratogenic risk, however, for pregnant women receiving Dex treatment. It has been claimed that Dex exposure during pregnancy could affect osteogenesis in the developing embryo, which still remains highly controversial. In this study, we employed chick embryos to investigate the effects of Dex exposure on skeletal development using combined in vivo and in vitro approach. First, we demonstrated that Dex (10 −8 –10 −6 μmol/egg) exposure resulted in a shortening of the developing long bones of chick embryos, and it accelerated the deposition of calcium salts. Secondly, histological analysis of chick embryo phalanxes exhibited Dex exposure inhibited the proliferation of chondrocytes, increased apoptosis of chondrocytes and osteocytes, and led to atypical arranged hypertrophic chondrocytes. The expression of genes related to skeletogenesis was also analyzed by semi-quantitative RT-PCR. The expression of ALP, Col1a2 and Col2a1 was decreased in the Dex treated phalanxes. A detectable increase was observed in Runx-2 and Mmp-13 expression. We next examined how Dex affected the different stages of skeletogenesis in vitro. Utilizing limb bud mesenchyme micromass cultures, we determined that Dex exposure exerted no effect on apoptosis but impaired chondrogenic cell proliferation. Interestingly, low dose of Dex moderately prompted nodule formation as revealed by alcian blue staining, but higher doses of Dex significantly inhibited similar chondrogenic differentiation. Dex exposure did not induce apoptosis when the chondrogenic precursors were still at the mesenchymal stage, however, cell viability was suppressed when the mesenchyme differentiated into chondrocytes. Alizarin red staining revealed that the capacity to form mineralized bone nodules was correspondingly enhanced as Dex concentrations increased. The mRNA level of Sox-9 was slightly increased

  3. Biphasic influence of dexamethasone exposure on embryonic vertebrate skeleton development

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Xin; Chen, Jian-long; Ma, Zheng-lai; Zhang, Zhao-long; Lv, Shun; Mai, Dong-mei; Liu, Jia-jia [Department of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Medicine, Jinan University, Guangzhou 510632 (China); Chuai, Manli [Division of Cell and Developmental Biology, University of Dundee, Dundee DD1 5EH (United Kingdom); Lee, Kenneth Ka Ho; Wan, Chao [Stem Cell and Regeneration Thematic Research Programme, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin (Hong Kong); Yang, Xuesong, E-mail: yang_xuesong@126.com [Department of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Medicine, Jinan University, Guangzhou 510632 (China); Institute of Fetal-Preterm Labor Medicine, Jinan University, Guangzhou 510632 (China)

    2014-11-15

    Dexamethasone (Dex) has anti-inflammatory and immunomodulatory properties against many conditions. There is a potential teratogenic risk, however, for pregnant women receiving Dex treatment. It has been claimed that Dex exposure during pregnancy could affect osteogenesis in the developing embryo, which still remains highly controversial. In this study, we employed chick embryos to investigate the effects of Dex exposure on skeletal development using combined in vivo and in vitro approach. First, we demonstrated that Dex (10{sup −8}–10{sup −6} μmol/egg) exposure resulted in a shortening of the developing long bones of chick embryos, and it accelerated the deposition of calcium salts. Secondly, histological analysis of chick embryo phalanxes exhibited Dex exposure inhibited the proliferation of chondrocytes, increased apoptosis of chondrocytes and osteocytes, and led to atypical arranged hypertrophic chondrocytes. The expression of genes related to skeletogenesis was also analyzed by semi-quantitative RT-PCR. The expression of ALP, Col1a2 and Col2a1 was decreased in the Dex treated phalanxes. A detectable increase was observed in Runx-2 and Mmp-13 expression. We next examined how Dex affected the different stages of skeletogenesis in vitro. Utilizing limb bud mesenchyme micromass cultures, we determined that Dex exposure exerted no effect on apoptosis but impaired chondrogenic cell proliferation. Interestingly, low dose of Dex moderately prompted nodule formation as revealed by alcian blue staining, but higher doses of Dex significantly inhibited similar chondrogenic differentiation. Dex exposure did not induce apoptosis when the chondrogenic precursors were still at the mesenchymal stage, however, cell viability was suppressed when the mesenchyme differentiated into chondrocytes. Alizarin red staining revealed that the capacity to form mineralized bone nodules was correspondingly enhanced as Dex concentrations increased. The mRNA level of Sox-9 was slightly

  4. The osteoinductive effect of chitosan-collagen composites around pure titanium implant surfaces in rats.

    Science.gov (United States)

    Kung, S; Devlin, H; Fu, E; Ho, K-Y; Liang, S-Y; Hsieh, Y-D

    2011-02-01

    The enhancing effects of chitosan on activation of platelets and differentiation of osteoprogenitor cells have been demonstrated in vitro. The purpose of this study was to evaluate the in vivo osteoinductive effect of chitosan-collagen composites around pure titanium implant surfaces. Chitosan-collagen composites containing chitosan of different molecular weights (450 and 750 kDa) were wrapped onto titanium implants and embedded into the subcutaneous area on the back of 15 Sprague-Dawley rats. The control consisted of implants wrapped with plain collagen type I membranes. Implants and surrounding tissues were retrieved 6 wks after surgery and identified by Alizarin red and Alcian blue whole mount staining. The newly formed structures in the test groups were further analyzed by Toluidine blue and Masson-Goldner trichrome staining, and immunohistochemical staining with osteopontin and alkaline phosphotase. The bone formation parameters of the new bone in the two test groups were measured and compared. New bone formed ectopically in both chitosan-collagen groups, whereas no bone induction occurred in the negative control group. These newly formed bone-like structures were further confirmed by immunohistochemical staining. Comparison of bone parameters of the newly induced bone revealed no statistically significant differences between the 450 and 750 kDa chitosan-collagen groups. Our results demonstrated that chitosan-collagen composites might induce in vivo new bone formation around pure titanium implant surfaces. Different molecular weights of chitosan did not show significantly different effects on the osteoinductive potential of the test materials. © 2010 John Wiley & Sons A/S.

  5. Calcium supplements

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  6. Obtaining of ceramics biphasic dense and porous

    International Nuclear Information System (INIS)

    Pallone, E.M.J.A.; Rigo, E.C.S.; Fraga, A.F.

    2010-01-01

    Among the bioceramic hydroxyapatite (HAP) and beta-tricalcium phosphate (beta-TCP) are materials commonly used in biomedical field. Their combined properties result in a material with absorbable and at the same time with bioactive surface. Called biphasic ceramics such materials respond more quickly when exposed to physiological environment. In this work, powders of HAP/beta-TCP were obtained by chemical precipitation. After obtaining the post-phase was added at a ratio of 0, 15% and 30w% aqueous solutions of corn starch in order to obtain porous bodies. After mixing the resulting solutions were dried, resigned in tablet form and sintered at 1300 deg C. The initial powder was characterized by X-ray diffraction with Rietveld refinement to quantify the phases present. Bodies-of-evidence has been characterized by calculating the bulk density, X-ray diffraction (XRD), scanning electron microscopy and diametral compression. (author)

  7. Calcium absorption

    International Nuclear Information System (INIS)

    Carlmark, B.; Reizenstein, P.; Dudley, R.A.

    1976-01-01

    The methods most commonly used to measure the absorption and retention of orally administered calcium are reviewed. Nearly all make use of calcium radioisotopes. The magnitude of calcium absorption and retention depends upon the chemical form and amount of calcium administered, and the clinical and nutritional status of the subject; these influences are briefly surveyed. (author)

  8. Strontium hydroxyapatite/chitosan nanohybrid scaffolds with enhanced osteoinductivity for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Yong [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Xu, Zhengliang [Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, 600 Yishan Road, Shanghai 200233 (China); Ke, Qinfei [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Yin, Wenjing; Chen, Yixuan [Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, 600 Yishan Road, Shanghai 200233 (China); Zhang, Changqing, E-mail: zhangcq@sjtu.edu.cn [Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, 600 Yishan Road, Shanghai 200233 (China); Guo, Yaping, E-mail: ypguo@shnu.edu.cn [The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China)

    2017-03-01

    For the clinical application of bone tissue engineering with the combination of biomaterials and mesenchymal stem cells (MSCs), bone scaffolds should possess excellent biocompatibility and osteoinductivity to accelerate the repair of bone defects. Herein, strontium hydroxyapatite [SrHAP, Ca{sub 10−x}Sr{sub x}(PO{sub 4}){sub 6}(OH){sub 2}]/chitosan (CS) nanohybrid scaffolds were fabricated by a freeze-drying method. The SrHAP nanocrystals with the different x values of 0, 1, 5 and 10 are abbreviated to HAP, Sr1HAP, Sr5HAP and Sr10HAP, respectively. With increasing x values from 0 to 10, the crystal cell volumes and axial lengths of SrHAP become gradually large because of the greater ion radius of Sr{sup 2+} than Ca{sup 2+}, while the crystal sizes of SrHAP decrease from 70.4 nm to 46.7 nm. The SrHAP/CS nanohybrid scaffolds exhibits three-dimensional (3D) interconnected macropores with pore sizes of 100–400 μm, and the SrHAP nanocrystals are uniformly dispersed within the scaffolds. In vitro cell experiments reveal that all the HAP/CS, Sr1HAP/CS, Sr5HAP/CS and Sr10HAP/CS nanohybrid scaffolds possess excellent cytocompatibility with the favorable adhesion, spreading and proliferation of human bone marrow mesenchymal stem cells (hBMSCs). The Sr5HAP nanocrystals in the scaffolds do not affect the adhesion, spreading of hBMSCs, but they contribute remarkably to cell proliferation and osteogenic differentiation. As compared with the HAP/CS nanohybrid scaffold, the released Sr{sup 2+} ions from the SrHAP/CS nanohybrid scaffolds enhance alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization and osteogenic-related COL-1 and ALP expression levels. Especially, the Sr5HAP/CS nanohybrid scaffolds exhibit the best osteoinductivity among four groups because of the synergetic effect between Ca{sup 2+} and Sr{sup 2+} ions. Hence, the Sr5HAP/CS nanohybrid scaffolds with excellent cytocompatibility and osteogenic property have promising application for

  9. Strontium hydroxyapatite/chitosan nanohybrid scaffolds with enhanced osteoinductivity for bone tissue engineering

    International Nuclear Information System (INIS)

    Lei, Yong; Xu, Zhengliang; Ke, Qinfei; Yin, Wenjing; Chen, Yixuan; Zhang, Changqing; Guo, Yaping

    2017-01-01

    For the clinical application of bone tissue engineering with the combination of biomaterials and mesenchymal stem cells (MSCs), bone scaffolds should possess excellent biocompatibility and osteoinductivity to accelerate the repair of bone defects. Herein, strontium hydroxyapatite [SrHAP, Ca 10−x Sr x (PO 4 ) 6 (OH) 2 ]/chitosan (CS) nanohybrid scaffolds were fabricated by a freeze-drying method. The SrHAP nanocrystals with the different x values of 0, 1, 5 and 10 are abbreviated to HAP, Sr1HAP, Sr5HAP and Sr10HAP, respectively. With increasing x values from 0 to 10, the crystal cell volumes and axial lengths of SrHAP become gradually large because of the greater ion radius of Sr 2+ than Ca 2+ , while the crystal sizes of SrHAP decrease from 70.4 nm to 46.7 nm. The SrHAP/CS nanohybrid scaffolds exhibits three-dimensional (3D) interconnected macropores with pore sizes of 100–400 μm, and the SrHAP nanocrystals are uniformly dispersed within the scaffolds. In vitro cell experiments reveal that all the HAP/CS, Sr1HAP/CS, Sr5HAP/CS and Sr10HAP/CS nanohybrid scaffolds possess excellent cytocompatibility with the favorable adhesion, spreading and proliferation of human bone marrow mesenchymal stem cells (hBMSCs). The Sr5HAP nanocrystals in the scaffolds do not affect the adhesion, spreading of hBMSCs, but they contribute remarkably to cell proliferation and osteogenic differentiation. As compared with the HAP/CS nanohybrid scaffold, the released Sr 2+ ions from the SrHAP/CS nanohybrid scaffolds enhance alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization and osteogenic-related COL-1 and ALP expression levels. Especially, the Sr5HAP/CS nanohybrid scaffolds exhibit the best osteoinductivity among four groups because of the synergetic effect between Ca 2+ and Sr 2+ ions. Hence, the Sr5HAP/CS nanohybrid scaffolds with excellent cytocompatibility and osteogenic property have promising application for bone tissue engineering. - Highlights: • We

  10. Strontium hydroxyapatite/chitosan nanohybrid scaffolds with enhanced osteoinductivity for bone tissue engineering.

    Science.gov (United States)

    Lei, Yong; Xu, Zhengliang; Ke, Qinfei; Yin, Wenjing; Chen, Yixuan; Zhang, Changqing; Guo, Yaping

    2017-03-01

    For the clinical application of bone tissue engineering with the combination of biomaterials and mesenchymal stem cells (MSCs), bone scaffolds should possess excellent biocompatibility and osteoinductivity to accelerate the repair of bone defects. Herein, strontium hydroxyapatite [SrHAP, Ca 10-x Sr x (PO 4 ) 6 (OH) 2 ]/chitosan (CS) nanohybrid scaffolds were fabricated by a freeze-drying method. The SrHAP nanocrystals with the different x values of 0, 1, 5 and 10 are abbreviated to HAP, Sr1HAP, Sr5HAP and Sr10HAP, respectively. With increasing x values from 0 to 10, the crystal cell volumes and axial lengths of SrHAP become gradually large because of the greater ion radius of Sr 2+ than Ca 2+ , while the crystal sizes of SrHAP decrease from 70.4nm to 46.7nm. The SrHAP/CS nanohybrid scaffolds exhibits three-dimensional (3D) interconnected macropores with pore sizes of 100-400μm, and the SrHAP nanocrystals are uniformly dispersed within the scaffolds. In vitro cell experiments reveal that all the HAP/CS, Sr1HAP/CS, Sr5HAP/CS and Sr10HAP/CS nanohybrid scaffolds possess excellent cytocompatibility with the favorable adhesion, spreading and proliferation of human bone marrow mesenchymal stem cells (hBMSCs). The Sr5HAP nanocrystals in the scaffolds do not affect the adhesion, spreading of hBMSCs, but they contribute remarkably to cell proliferation and osteogenic differentiation. As compared with the HAP/CS nanohybrid scaffold, the released Sr 2+ ions from the SrHAP/CS nanohybrid scaffolds enhance alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization and osteogenic-related COL-1 and ALP expression levels. Especially, the Sr5HAP/CS nanohybrid scaffolds exhibit the best osteoinductivity among four groups because of the synergetic effect between Ca 2+ and Sr 2+ ions. Hence, the Sr5HAP/CS nanohybrid scaffolds with excellent cytocompatibility and osteogenic property have promising application for bone tissue engineering. Copyright © 2016. Published

  11. Bone Morphogenic Protein-2 (rhBMP2)-Loaded Silk Fibroin Scaffolds to Enhance the Osteoinductivity in Bone Tissue Engineering

    Science.gov (United States)

    Du, Guang-Yu; He, Sheng-Wei; Sun, Chuan-Xiu; Mi, Li-Dong

    2017-10-01

    There is an increasing demand for formulations of silk fibroin (SF) scaffolds in biomedical applications. SF was crosslinked via glutaraldehyde with osteoinductive recombinant human bone morphogenic protein-2 (rhBMP2) of different ratios viz. (i) 3% SF with no rhBMP2 (SF), (ii) 3% SF with equal amount of rhBMP2 (SF+BMP2), and (iii) 12% SF with 3% of rhBMP2 (4SF+BMP2), and these solutions were used in electrospinning-based fabrication of nanoscaffolds for evaluating increased osteoinductive potential of SF scaffolds with rhBMP2. Stress-strain relationship suggested there is no loss in mechanical strength of fibers with addition of rhBMP2, and mechanical strength of scaffold was improved with increase in concentration of SF. rhBMP2 association increased the water retention capacity of scaffold as evident from swelling studies. Viability of hMSCs was found to be higher in conjugated scaffolds, and scaffolds do not exhibit any cytotoxicity towards guest cells. Cells were found to have higher alkaline phosphatase activity in conjugated scaffolds under in vitro and in vivo conditions which establishes the increased osteoinductivity of the novel construct. The scaffolds were found to be effective for in vivo bone formation as well.

  12. Calcium binding properties of calcium dependent protein kinase 1 (CaCDPK1) from Cicer arietinum.

    Science.gov (United States)

    Dixit, Ajay Kumar; Jayabaskaran, Chelliah

    2015-05-01

    Calcium plays a crucial role as a secondary messenger in all aspects of plant growth, development and survival. Calcium dependent protein kinases (CDPKs) are the major calcium decoders, which couple the changes in calcium level to an appropriate physiological response. The mechanism by which calcium regulates CDPK protein is not well understood. In this study, we investigated the interactions of Ca(2+) ions with the CDPK1 isoform of Cicer arietinum (CaCDPK1) using a combination of biophysical tools. CaCDPK1 has four different EF hands as predicted by protein sequence analysis. The fluorescence emission spectrum of CaCDPK1 showed quenching with a 5 nm red shift upon addition of calcium, indicating conformational changes in the tertiary structure. The plot of changes in intensity against calcium concentrations showed a biphasic curve with binding constants of 1.29 μM and 120 μM indicating two kinds of binding sites. Isothermal calorimetric (ITC) titration with CaCl2 also showed a biphasic curve with two binding constants of 0.027 μM and 1.7 μM. Circular dichroism (CD) spectra showed two prominent peaks at 208 and 222 nm indicating that CaCDPK1 is a α-helical rich protein. Calcium binding further increased the α-helical content of CaCDPK1 from 75 to 81%. Addition of calcium to CaCDPK1 also increased fluorescence of 8-anilinonaphthalene-1-sulfonic acid (ANS) indicating exposure of hydrophobic surfaces. Thus, on the whole this study provides evidence for calcium induced conformational changes, exposure of hydrophobic surfaces and heterogeneity of EF hands in CaCDPK1. Copyright © 2015 Elsevier GmbH. All rights reserved.

  13. Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

    Science.gov (United States)

    Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

    2008-02-28

    The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

  14. BMP2-loaded hollow hydroxyapatite microspheres exhibit enhanced osteoinduction and osteogenicity in large bone defects.

    Science.gov (United States)

    Xiong, Long; Zeng, Jianhua; Yao, Aihua; Tu, Qiquan; Li, Jingtang; Yan, Liang; Tang, Zhiming

    2015-01-01

    The regeneration of large bone defects is an osteoinductive, osteoconductive, and osteogenic process that often requires a bone graft for support. Limitations associated with naturally autogenic or allogenic bone grafts have demonstrated the need for synthetic substitutes. The present study investigates the feasibility of using novel hollow hydroxyapatite microspheres as an osteoconductive matrix and a carrier for controlled local delivery of bone morphogenetic protein 2 (BMP2), a potent osteogenic inducer of bone regeneration. Hollow hydroxyapatite microspheres (100±25 μm) with a core (60±18 μm) and a mesoporous shell (180±42 m(2)/g surface area) were prepared by a glass conversion technique and loaded with recombinant human BMP2 (1 μg/mg). There was a gentle burst release of BMP2 from microspheres into the surrounding phosphate-buffered saline in vitro within the initial 48 hours, and continued at a low rate for over 40 days. In comparison with hollow hydroxyapatite microspheres without BMP2 or soluble BMP2 without a carrier, BMP2-loaded hollow hydroxyapatite microspheres had a significantly enhanced capacity to reconstitute radial bone defects in rabbit, as shown by increased serum alkaline phosphatase; quick and complete new bone formation within 12 weeks; and great biomechanical flexural strength. These results indicate that BMP2-loaded hollow hydroxyapatite microspheres could be a potential new option for bone graft substitutes in bone regeneration.

  15. In Vitro Effects of Strontium on Proliferation and Osteoinduction of Human Preadipocytes

    Directory of Open Access Journals (Sweden)

    V. Nardone

    2015-01-01

    Full Text Available Development of tools to be used for in vivo bone tissue regeneration focuses on cellular models and differentiation processes. In searching for all the optimal sources, adipose tissue-derived mesenchymal stem cells (hADSCs or preadipocytes are able to differentiate into osteoblasts with analogous characteristics to bone marrow mesenchymal stem cells, producing alkaline phosphatase (ALP, collagen, osteocalcin, and calcified nodules, mainly composed of hydroxyapatite (HA. The possibility to influence bone differentiation of stem cells encompasses local and systemic methods, including the use of drugs administered systemically. Among the latter, strontium ranelate (SR represents an interesting compound, acting as an uncoupling factor that stimulates bone formation and inhibits bone resorption. The aim of our study was to evaluate the in vitro effects of a wide range of strontium (Sr2+ concentrations on proliferation, ALP activity, and mineralization of a novel finite clonal hADSCs cell line, named PA20-h5. Sr2+ promoted PA20-h5 cell proliferation while inducing the increase of ALP activity and gene expression as well as HA production during in vitro osteoinduction. These findings indicate a role for Sr2+ in supporting bone regeneration during the process of skeletal repair in general, and, more specifically, when cell therapies are applied.

  16. Biological Strategies for Improved Osseointegration and Osteoinduction of Porous Metal Orthopedic Implants

    Science.gov (United States)

    Riester, Scott M.; Bonin, Carolina A.; Kremers, Hilal Maradit; Dudakovic, Amel; Kakar, Sanjeev; Cohen, Robert C.; Westendorf, Jennifer J.

    2015-01-01

    The biological interface between an orthopedic implant and the surrounding host tissue may have a dramatic effect upon clinical outcome. Desired effects include bony ingrowth (osseointegration), stimulation of osteogenesis (osteoinduction), increased vascularization, and improved mechanical stability. Implant loosening, fibrous encapsulation, corrosion, infection, and inflammation, as well as physical mismatch may have deleterious clinical effects. This is particularly true of implants used in the reconstruction of load-bearing synovial joints such as the knee, hip, and the shoulder. The surfaces of orthopedic implants have evolved from solid-smooth to roughened-coarse and most recently, to porous in an effort to create a three-dimensional architecture for bone apposition and osseointegration. Total joint surgeries are increasingly performed in younger individuals with a longer life expectancy, and therefore, the postimplantation lifespan of devices must increase commensurately. This review discusses advancements in biomaterials science and cell-based therapies that may further improve orthopedic success rates. We focus on material and biological properties of orthopedic implants fabricated from porous metal and highlight some relevant developments in stem-cell research. We posit that the ideal primary and revision orthopedic load-bearing metal implants are highly porous and may be chemically modified to induce stem cell growth and osteogenic differentiation, while minimizing inflammation and infection. We conclude that integration of new biological, chemical, and mechanical methods is likely to yield more effective strategies to control and modify the implant–bone interface and thereby improve long-term clinical outcomes. PMID:25348836

  17. Bone regeneration: Biomaterials as local delivery systems with improved osteoinductive properties.

    Science.gov (United States)

    Martin, Victor; Bettencourt, Ana

    2018-01-01

    Bone is a mineralized conjunctive tissue, with a unique trauma healing capability. However, the replacement or regeneration of lost bone is not always successful and becomes more difficult the wider the bone defect. A significant growth in the demand for orthopedic and maxillofacial surgical procedures as a result of population aging and increase in chronic diseases as diabetes is a fact and successful approaches for bone regeneration are still needed. Until today, autogenous bone graft continues to be the best solution even with important limitations, as quantity and the requirement of a donator area. Alternatively, local delivery systems combining an osteoconductive biomaterial with osteoinductive compounds as hormones, growth factors or drugs is a popular approach aiming to replace the need for autogenous bone grafts. Nevertheless, in spite of the intense research in the area, presently there is no system that can mimic all the biological functions of the autogenous bone grafts. In this context, the present work provides an overview of the most recent advances in the field of synthetic bone grafts. The opportunities and limitations are detailed along with the remaining gaps in the research that are still preventing the successful translation of more products into the market able to be a valuable option in comparison to the autogenous bone grafts. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Stoichiometric implications of a biphasic life cycle.

    Science.gov (United States)

    Tiegs, Scott D; Berven, Keith A; Carmack, Douglas J; Capps, Krista A

    2016-03-01

    Animals mediate flows of elements and energy in ecosystems through processes such as nutrient sequestration in body tissues, and mineralization through excretion. For taxa with biphasic life cycles, the dramatic shifts in anatomy and physiology that occur during ontogeny are expected to be accompanied by changes in body and excreta stoichiometry, but remain little-explored, especially in vertebrates. Here we tested stoichiometric hypotheses related to the bodies and excreta of the wood frog (Lithobates sylvaticus) across life stages and during larval development. Per-capita rates of nitrogen (N) and phosphorus (P) excretion varied widely during larval ontogeny, followed unimodal patterns, and peaked midway through development (Taylor-Kollros stages XV and XII, respectively). Larval mass did not increase steadily during development but peaked at stage XVII and declined until the termination of the experiment at stage XXII. Mass-specific N and P excretion rates of the larvae decreased exponentially during development. When coupled with population-biomass estimates, population-level excretion rates were greatest at stages VIII-X. Percent carbon (C), N, and C:N of body tissue showed weak trends across major life stages; body P and C:P, however, increased sixfold during development from egg to adult. Our results demonstrate that intraspecific ontogenic changes in nutrient contents of excretion and body tissues can be significant, and that N and P are not always excreted proportionally throughout life cycles. These results highlight the dynamic roles that species play in ecosystems, and how the morphological and physiological changes that accompany ontogeny can influence ecosystem-level processes.

  19. Calcium - ionized

    Science.gov (United States)

    ... diuretics Thrombocytosis (high platelet count) Tumors Vitamin A excess Vitamin D excess Lower-than-normal levels may be due to: Hypoparathyroidism Malabsorption Osteomalacia Pancreatitis Renal failure Rickets Vitamin D deficiency Alternative Names Free calcium; Ionized calcium ...

  20. Calcium Carbonate

    Science.gov (United States)

    ... Calcium is needed by the body for healthy bones, muscles, nervous system, and heart. Calcium carbonate also ... to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in ...

  1. Human decellularized bone scaffolds from aged donors show improved osteoinductive capacity compared to young donor bone.

    Directory of Open Access Journals (Sweden)

    Christopher A Smith

    Full Text Available To improve the safe use of allograft bone, decellularization techniques may be utilized to produce acellular scaffolds. Such scaffolds should retain their innate biological and biomechanical capacity and support mesenchymal stem cell (MSC osteogenic differentiation. However, as allograft bone is derived from a wide age-range, this study aimed to determine whether donor age impacts on the ability an osteoinductive, acellular scaffold produced from human bone to promote the osteogenic differentiation of bone marrow MSCs (BM-MSC. BM-MSCs from young and old donors were seeded on acellular bone cubes from young and old donors undergoing osteoarthritis related hip surgery. All combinations resulted in increased osteogenic gene expression, and alkaline phosphatase (ALP enzyme activity, however BM-MSCs cultured on old donor bone displayed the largest increases. BM-MSCs cultured in old donor bone conditioned media also displayed higher osteogenic gene expression and ALP activity than those exposed to young donor bone conditioned media. ELISA and Luminex analysis of conditioned media demonstrated similar levels of bioactive factors between age groups; however, IGF binding protein 1 (IGFBP1 concentration was significantly higher in young donor samples. Additionally, structural analysis of old donor bone indicated an increased porosity compared to young donor bone. These results demonstrate the ability of a decellularized scaffold produced from young and old donors to support osteogenic differentiation of cells from young and old donors. Significantly, the older donor bone produced greater osteogenic differentiation which may be related to reduced IGFBP1 bioavailability and increased porosity, potentially explaining the excellent clinical results seen with the use of allograft from aged donors.

  2. Osteoinduction on acid and heat treated porous Ti metal samples in canine muscle.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Kawai

    Full Text Available Samples of porous Ti metal were subjected to different acid and heat treatments. Ectopic bone formation on specimens embedded in dog muscle was compared with the surface characteristics of the specimen. Treatment of the specimens by H2SO4/HCl and heating at 600 °C produced micrometer-scale roughness with surface layers composed of rutile phase of titanium dioxide. The acid- and heat-treated specimens induced ectopic bone formation within 6 months of implantation. A specimen treated using NaOH followed by HCl acid and then heat treatment produced nanometer-scale surface roughness with a surface layer composed of both rutile and anatase phases of titanium dioxide. These specimens also induced bone formation after 6 months of implantation. Both these specimens featured positive surface charge and good apatite-forming abilities in a simulated body fluid. The amount of the bone induced in the porous structure increased with apatite-forming ability and higher positive surface charge. Untreated porous Ti metal samples showed no bone formation even after 12 months. Specimens that were only heat treated featured a smooth surface composed of rutile. A mixed acid treatment produced specimens with micrometer-scale rough surfaces composed of titanium hydride. Both of them also showed no bone formation after 12 months. The specimens that showed no bone formation also featured almost zero surface charge and no apatite-forming ability. These results indicate that osteoinduction of these porous Ti metal samples is directly related to positive surface charge that facilitates formation of apatite on the metal surfaces in vitro.

  3. Inflammation Intensity-dependent Expression of Osteoinductive Wnt Proteins is Critical for Ectopic New Bone Formation in Ankylosing Spondylitis.

    Science.gov (United States)

    Li, Xiang; Wang, Jianru; Zhan, Zhongping; Li, Sibei; Zheng, Zhaomin; Wang, Taiping; Zhang, Kuibo; Pan, Hehai; Li, Zemin; Zhang, Nu; Liu, Hui

    2018-02-26

    To investigate the molecular mechanism underlying the inflammation- related ectopic new bone formation in ankylosing spondylitis (AS). Spinal tissues and sera were collected from patients or normal volunteers to detect the expression of Wnt proteins. An in vitro cell culture system mimicking the local inflammatory microenvironment of bone-forming sites was established to study the relationship between inflammation and Wnt expression, the regulatory mechanism of inflammation-induced Wnt expression and the role of Wnt signaling in new bone formation. A modified collagen-induced arthritis (mCIA) and a proteoglycan -induced spondylitis (PGIS) animal model were used to confirm the key findings in vivo. The levels of osteoinductive Wnt proteins were obviously increased in the sera and spinal ligament tissues of patients with AS. Only constitutive low-intensity TNF-α stimulation, but not short-term or high-intensity TNF-α stimulation, induced persistent expression of osteoinductive Wnt proteins and subsequent bone formation through NF-κB (p65) and JNK/AP-1 (c-Jun) signaling pathways. Furthermore, inhibition of either Wnt/β-catenin or Wnt/PKCδ pathway significantly suppressed new bone formation. The increased expression of Wnt proteins was confirmed in both mCIA and PGIS models. A kyphotic and ankylosing phenotype of the spine was observed during long-term observation in mCIA model. Inhibition of either Wnt/β-catenin or Wnt/PKCδ signaling pathway significantly reduced the incidence and severity of this phenotype. Inflammation intensity-dependent expression of osteoinductive Wnt proteins is a key link between inflammation and ectopic new bone formation in AS. Activation of both canonical Wnt/β-catenin and noncanonical Wnt/PKCδ pathways is required for inflammation-induced new bone formation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. Progress on the biphase turbine at Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Cerini, D.; Hays, L.; Studhalter, W. [Douglas Energy Company, Placentia, CA (United States)

    1997-12-31

    The status of a Biphase turbine power plant being installed at the Cerro Prieto geothermal field is presented. The major modules for the power plant are completed except for a back pressure steam turbine. The power plant will be started in April 1997 with the Biphase turbine alone followed by the addition of the steam turbine module two months later. The current power plant performance level is 2780 kWe due to a decline in the well. An increase in power output to 4060 kWe by adding the flow from another well is planned. The addition of five Biphase power plants with a total power output of 21.2 megawatts is described.

  5. Biphasic Malignant Pleural Mesothelioma Masquerading as a Primary Skeletal Tumor

    Directory of Open Access Journals (Sweden)

    James Benjamin Gleason

    2016-01-01

    Full Text Available Biphasic malignant pleural mesothelioma is a rare malignant tumor, usually presenting as a pleural-based mass in a patient with history of chronic asbestos exposure. We herein report a case of a 41-year-old man who presented with chest pain and had a chest computed tomography (CT scan suggestive of a primary skeletal tumor originating from the ribs (chondrosarcoma or osteosarcoma, with no history of asbestos exposure. CT-guided core needle biopsies were diagnosed as malignant sarcomatoid mesothelioma. Surgical resection and chest wall reconstruction were performed, confirming the diagnosis and revealing a secondary histologic component (epithelioid, supporting the diagnosis of biphasic malignant mesothelioma.

  6. Early osteoinductive human bone marrow mesenchymal stromal/stem cells support an enhanced hematopoietic cell expansion with altered chemotaxis- and adhesion-related gene expression profiles

    Energy Technology Data Exchange (ETDEWEB)

    Sugino, Noriko [Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Miura, Yasuo, E-mail: ym58f5@kuhp.kyoto-u.ac.jp [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Yao, Hisayuki [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Iwasa, Masaki; Fujishiro, Aya [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Division of Gastroenterology and Hematology, Shiga University of Medical Science, Shiga 520-2192 (Japan); Fujii, Sumie [Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Hirai, Hideyo [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan); Takaori-Kondo, Akifumi [Department of Hematology/Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan); Ichinohe, Tatsuo [Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Maekawa, Taira [Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto 606-8507 (Japan)

    2016-01-22

    Bone marrow (BM) microenvironment has a crucial role in supporting hematopoiesis. Here, by using a microarray analysis, we demonstrate that human BM mesenchymal stromal/stem cells (MSCs) in an early osteoinductive stage (e-MSCs) are characterized by unique hematopoiesis-associated gene expression with an enhanced hematopoiesis-supportive ability. In comparison to BM-MSCs without osteoinductive treatment, gene expression in e-MSCs was significantly altered in terms of their cell adhesion- and chemotaxis-related profiles, as identified with Gene Ontology and Gene Set Enrichment Analysis. Noteworthy, expression of the hematopoiesis-associated molecules CXCL12 and vascular cell adhesion molecule 1 was remarkably decreased in e-MSCs. e-MSCs supported an enhanced expansion of CD34{sup +} hematopoietic stem and progenitor cells, and generation of myeloid lineage cells in vitro. In addition, short-term osteoinductive treatment favored in vivo hematopoietic recovery in lethally irradiated mice that underwent BM transplantation. e-MSCs exhibited the absence of decreased stemness-associated gene expression, increased osteogenesis-associated gene expression, and apparent mineralization, thus maintaining the ability to differentiate into adipogenic cells. Our findings demonstrate the unique biological characteristics of e-MSCs as hematopoiesis-regulatory stromal cells at differentiation stage between MSCs and osteoprogenitor cells and have significant implications in developing new strategy for using pharmacological osteoinductive treatment to support hematopoiesis in hematopoietic stem and progenitor cell transplantation. - Highlights: • Human BM-MSCs in an early osteoinductive stage (e-MSCs) support hematopoiesis. • Adhesion- and chemotaxis-associated gene signatures are altered in e-MSCs. • Expression of CXCL12 and VCAM1 is remarkably decreased in e-MSCs. • e-MSCs are at differentiation stage between MSCs and osteoprogenitor cells. • Osteoinductive treatment

  7. Deep eutectic solvents as performance additives in biphasic reactions

    NARCIS (Netherlands)

    Lan, Dongming; Wang, Xuping; Zhou, Pengfei; Hollmann, F.; Wang, Yonghua

    2017-01-01

    Deep eutectic solvents act as surfactants in biphasic (hydrophobic/aqueous) reaction mixtures enabling higher interfacial surface areas at lower mechanical stress as compared to simple emulsions. Exploiting this effect the rate of a chemoenzymatic epoxidation reaction was increased more than

  8. Biphasic Clinical Course Among Kenyan Children With Cerebral ...

    African Journals Online (AJOL)

    Background Cerebral malaria is the most severe neurological complication of Falciparum malaria. It is associated with a significant risk of death and neurological sequelae. A biphasic clinical picture is associated with an even greater risk of neurological sequelae. Objective To examine the incidence and clinical ...

  9. The osteoinductive potential of printable, cell-laden hydrogel-ceramic composites.

    NARCIS (Netherlands)

    Fedorovich, N.E.; Leeuwenburgh, S.C.G.; Helm, Y.J. van der; Alblas, J.; Dhert, W.J.

    2012-01-01

    Hydrogels used as injectables or in organ printing often lack the appropriate stimuli to direct osteogenic differentiation of embedded multipotent stromal cells (MSCs), resulting in limited bone formation in these matrices. Addition of calcium phosphate (CaP) particles to the printing mixture is

  10. Calcium waves.

    Science.gov (United States)

    Jaffe, Lionel F

    2008-04-12

    Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

  11. Effects of calcium phosphate/chitosan composite on bone healing in rats: calcium phosphate induces osteon formation.

    Science.gov (United States)

    Fernández, Tulio; Olave, Gilberto; Valencia, Carlos H; Arce, Sandra; Quinn, Julian M W; Thouas, George A; Chen, Qi-Zhi

    2014-07-01

    Vascularization of an artificial graft represents one of the most significant challenges facing the field of bone tissue engineering. Over the past decade, strategies to vascularize artificial scaffolds have been intensively evaluated using osteoinductive calcium phosphate (CaP) biomaterials in animal models. In this work, we observed that CaP-based biomaterials implanted into rat calvarial defects showed remarkably accelerated formation and mineralization of new woven bone in defects in the initial stages, at a rate of ∼60 μm/day (0.8 mg/day), which was considerably higher than normal bone growth rates (several μm/day, 0.1 mg/day) in implant-free controls of the same age. Surprisingly, we also observed histological evidence of primary osteon formation, indicated by blood vessels in early-region fibrous tissue, which was encapsulated by lamellar osteocyte structures. These were later fully replaced by compact bone, indicating complete regeneration of calvarial bone. Thus, the CaP biomaterial used here is not only osteoinductive, but vasculogenic, and it may have contributed to the bone regeneration, despite an absence of osteons in normal rat calvaria. Further investigation will involve how this strategy can regulate formation of vascularized cortical bone such as by control of degradation rate, and use of models of long, dense bones, to more closely approximate repair of human cortical bone.

  12. Review of biphasic insulin aspart in the treatment of type 1 and 2 diabetes

    Directory of Open Access Journals (Sweden)

    Nazia Raja-Khan

    2008-01-01

    Full Text Available Nazia Raja-Khan, Sarah S Warehime, Robert A GabbayDivision of Endocrinology, Diabetes, and Metabolism, Penn State Institute for Diabetes and Obesity, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USABackground: Insulin is an effective treatment for achieving glycemic control and preventing complications in patients with diabetes. In order to make insulin therapy more acceptable to patients, newer formulations of insulin have been developed, such as biphasic insulins. Biphasic insulins conveniently provide both prandial and basal insulin in a single injection. One of the most well-studied biphasic insulins is biphasic insulin aspart 70/30.Objective: Our goal was to review the current literature on the safety and efficacy of biphasic insulin aspart in type 1 and type 2 diabetes.Methods: A MEDLINE search was conducted using the terms “biphasic insulin aspart” to identify clinical studies and reviews.Results: Biphasic insulin aspart more effectively reduces post-prandial glucose compared to other biphasic insulins and basal insulins. Compared to biphasic insulin aspart, fasting glucose levels are lower with NPH, similar with glargine, and similar or lower with biphasic human insulin. Treat-to-target trials have shown that a goal HbA1c below 6.5 or 7% can be achieved with biphasic insulin aspart. The risk of hypoglycemia is similar to or less than that seen with other biphasic insulins or NPH insulin.Conclusion: Biphasic insulin aspart 70/30 is a safe and effective treatment option for patients with diabetes.Keywords: biphasic insulin aspart, insulin, diabetes

  13. Synthesis and characterization of nanocomposite powders of calcium phosphate/titanium oxide for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Delima, S.A.; Camargo, N.H.A.; Souza, J.C.P.; Gemelli, E., E-mail: sarahamindelima@hotmail.com, E-mail: dem2nhac@joinville.udesc.br, E-mail: souzajulio@joinville.udesc.br, E-mail: gemelli@joinville.udesc.br [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas

    2009-07-01

    The nanostructured bioceramics of calcium phosphate are current themes of research and they are becoming important as bone matrix in regeneration of tissues in orthopedic and dental applications. Nanocomposite powders of calcium phosphate, reinforced with nanometric particles of titanium oxide, silica oxide and alumina oxid ealpha, are being widely studied because they offer new microstructures, nanostructures and interconnected microporosity with high superficial area of micropores that contribute to osteointegration and osteoinduction processes. This study is about the synthesis of nanocomposites powders of calcium phosphate reinforced with 1%, 2%, 3% and 5% in volume of titanium oxide and its characterization through the techniques of X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis (DTA), Thermogravimetry (TG) and Dilatometry. (author)

  14. Synthesis and characterization of nanocomposite powders of calcium phosphate/titanium oxide for biomedical applications

    International Nuclear Information System (INIS)

    Delima, S.A.; Camargo, N.H.A.; Souza, J.C.P.; Gemelli, E.

    2009-01-01

    The nanostructured bioceramics of calcium phosphate are current themes of research and they are becoming important as bone matrix in regeneration of tissues in orthopedic and dental applications. Nanocomposite powders of calcium phosphate, reinforced with nanometric particles of titanium oxide, silica oxide and alumina oxid ealpha, are being widely studied because they offer new microstructures, nanostructures and interconnected microporosity with high superficial area of micropores that contribute to osteointegration and osteoinduction processes. This study is about the synthesis of nanocomposites powders of calcium phosphate reinforced with 1%, 2%, 3% and 5% in volume of titanium oxide and its characterization through the techniques of X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis (DTA), Thermogravimetry (TG) and Dilatometry. (author)

  15. An Osteoconductive, Osteoinductive, and Osteogenic Tissue-Engineered Product for Trauma and Orthopaedic Surgery: How Far Are We?

    Directory of Open Access Journals (Sweden)

    Wasim S. Khan

    2012-01-01

    Full Text Available The management of large bone defects due to trauma, degenerative disease, congenital deformities, and tumor resection remains a complex issue for the orthopaedic reconstructive surgeons. The requirement is for an ideal bone replacement which is osteoconductive, osteoinductive, and osteogenic. Autologous bone grafts are still considered the gold standard for reconstruction of bone defects, but donor site morbidity and size limitations are major concern. The use of bioartificial bone tissues may help to overcome these problems. The reconstruction of large volume defects remains a challenge despite the success of reconstruction of small-to-moderate-sized bone defects using engineered bone tissues. The aim of this paper is to understand the principles of tissue engineering of bone and its clinical applications in reconstructive surgery.

  16. An osteoconductive, osteoinductive, and osteogenic tissue-engineered product for trauma and orthopaedic surgery: how far are we?

    Science.gov (United States)

    Khan, Wasim S; Rayan, Faizal; Dhinsa, Baljinder S; Marsh, David

    2012-01-01

    The management of large bone defects due to trauma, degenerative disease, congenital deformities, and tumor resection remains a complex issue for the orthopaedic reconstructive surgeons. The requirement is for an ideal bone replacement which is osteoconductive, osteoinductive, and osteogenic. Autologous bone grafts are still considered the gold standard for reconstruction of bone defects, but donor site morbidity and size limitations are major concern. The use of bioartificial bone tissues may help to overcome these problems. The reconstruction of large volume defects remains a challenge despite the success of reconstruction of small-to-moderate-sized bone defects using engineered bone tissues. The aim of this paper is to understand the principles of tissue engineering of bone and its clinical applications in reconstructive surgery.

  17. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha

    2015-01-01

    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p

  18. Actinide recovery using aqueous biphasic extraction: Initial developmental studies

    International Nuclear Information System (INIS)

    Chaiko, D.J.; Mensah-Biney, R.; Mertz, C.J.; Rollins, A.N.

    1992-08-01

    Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less

  19. Actinide recovery using aqueous biphasic extraction: Initial developmental studies

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, D.J.; Mensah-Biney, R.; Mertz, C.J.; Rollins, A.N.

    1992-08-01

    Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less.

  20. Injectable glycosaminoglycan-protein nano-complex in semi-interpenetrating networks: A biphasic hydrogel for hyaline cartilage regeneration.

    Science.gov (United States)

    Radhakrishnan, Janani; Subramanian, Anuradha; Sethuraman, Swaminathan

    2017-11-01

    Articular hyaline cartilage regeneration remains challenging due to its less intrinsic reparability. The study develops injectable biphasic semi-interpenetrating polymer networks (SIPN) hydrogel impregnated with chondroitin sulfate (ChS) nanoparticles for functional cartilage restoration. ChS loaded zein nanoparticles (∼150nm) prepared by polyelectrolyte-protein complexation were interspersed into injectable SIPNs developed by blending alginate with poly(vinyl alcohol) and calcium crosslinking. The hydrogel exhibited interconnected porous microstructure (39.9±5.8μm pore diameter, 57.7±5.9% porosity), 92% swellability and >350Pa elastic modulus. Primary chondrocytes compatibility, chondrocyte-matrix interaction with cell-cell clustering and spheroidal morphology was demonstrated in ChS loaded hydrogel and long-term (42days) proliferation was also determined. Higher fold expression of cartilage-specific genes sox9, aggrecan and collagen-II was observed in ChS loaded hydrogel while exhibiting poor expression of collagen-I. Immunoblotting of aggregan and collagen II demonstrate favorable positive influence of ChS on chondrocytes. Thus, the injectable biphasic SIPNs could be promising composition-mimetic substitute for cartilage restoration at irregular defects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Osteoclast-like cells on deproteinized bovine bone mineral and biphasic calcium phosphate

    DEFF Research Database (Denmark)

    Jensen, Simon S; Gruber, Reinhard; Buser, Daniel

    2015-01-01

    OBJECTIVES: The occurrence of multinucleated giant cells (MNGCs) on bone substitute materials has been recognized for a long time. However, there have been no studies linking material characteristics with morphology of the MNGCs. The aim was to analyze the qualitative differences of MNGCs on two ...... osteoclasts. CONCLUSION: MNGCs demonstrated distinctly different histological features depending on the bone substitute material used. Further research is warranted to understand the clinical implications of these morphological observations....

  2. Synthesis and characterization of nanostructured powders of hydroxyapatite and β-calcium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Prants, W.T.; Muller, D.T.; Orzechowski, L.G.; Feit, G.; Delima, S.A.; Camargo, N.H.A.; Gemelli, E., E-mail: w_prants@hotmail.com, E-mail: danielt_muller@yahoo.com.br, E-mail: sarahamindelima@hotmail.com, E-mail: dem2nhac@joinville.udesc.br, E-mail: gemelli@joinville.udesc.br [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Campus Universitario Prof. Avelino Marcante

    2009-07-01

    Biphasic calcium phosphate (BCP) bioceramics are composed in a general manner from a mixture between hydroxyapatite (HA), and β-calcium phosphate. In the recent years, the BCP bioceramics are pointed out in researches from regeneration and reconstitution in osseous tissue, in reason of their similar mineralogical characteristics of the human bone structure, as great biodegradation, absorption and formation of precocious osseous tissue. The biphasic materials (BCP) are detached for use in medical and dental application, as filling bone cavities, maxillofacial treatment, medicaments discharge for treatment cancerous osteomyelitis and antibiotics discharge related with orthopedic injuries reparation. The aim of this work focused in synthesis and characterization of hydroxyapatite and β-calcium phosphate. The presented results are related with the mineralogical characterization with X-ray diffraction, thermal behavior with Differential Scanning Calorimetry and Dilatometer. The Scanning Electronic Microscopy (SEM) was used to help in the morphological characterization of the nanostructured powders. (author)

  3. Synthesis and characterization of nanostructured powders of hydroxyapatite and β-calcium phosphate

    International Nuclear Information System (INIS)

    Prants, W.T.; Muller, D.T.; Orzechowski, L.G.; Feit, G.; Delima, S.A.; Camargo, N.H.A.; Gemelli, E.

    2009-01-01

    Biphasic calcium phosphate (BCP) bioceramics are composed in a general manner from a mixture between hydroxyapatite (HA), and β-calcium phosphate. In the recent years, the BCP bioceramics are pointed out in researches from regeneration and reconstitution in osseous tissue, in reason of their similar mineralogical characteristics of the human bone structure, as great biodegradation, absorption and formation of precocious osseous tissue. The biphasic materials (BCP) are detached for use in medical and dental application, as filling bone cavities, maxillofacial treatment, medicaments discharge for treatment cancerous osteomyelitis and antibiotics discharge related with orthopedic injuries reparation. The aim of this work focused in synthesis and characterization of hydroxyapatite and β-calcium phosphate. The presented results are related with the mineralogical characterization with X-ray diffraction, thermal behavior with Differential Scanning Calorimetry and Dilatometer. The Scanning Electronic Microscopy (SEM) was used to help in the morphological characterization of the nanostructured powders. (author)

  4. A new kinetic biphasic approach applied to biodiesel process intensification

    Energy Technology Data Exchange (ETDEWEB)

    Russo, V.; Tesser, R.; Di Serio, M.; Santacesaria, E. [Naples Univ. (Italy). Dept. of Chemistry

    2012-07-01

    Many different papers have been published on the kinetics of the transesterification of vegetable oil with methanol, in the presence of alkaline catalysts to produce biodiesel. All the proposed approaches are based on the assumption of a pseudo-monophasic system. The consequence of these approaches is that some experimental aspects cannot be described. For the reaction performed in batch conditions, for example, the monophasic approach is not able to reproduce the different plateau obtained by using different amount of catalyst or the induction time observed at low stirring rates. Moreover, it has been observed by operating in continuous reactors that micromixing has a dramatic effect on the reaction rate. At this purpose, we have recently observed that is possible to obtain a complete conversion to biodiesel in less than 10 seconds of reaction time. This observation is confirmed also by other authors using different types of reactors like: static mixers, micro-reactors, oscillatory flow reactors, cavitational reactors, microwave reactors or centrifugal contactors. In this work we will show that a recently proposed biphasic kinetic approach is able to describe all the aspects before mentioned that cannot be described by the monophasic kinetic model. In particular, we will show that the biphasic kinetic model can describe both the induction time observed in the batch reactors, at low stirring rate, and the very high conversions obtainable in a micro-channel reactor. The adopted biphasic kinetic model is based on a reliable reaction mechanism that will be validated by the experimental evidences reported in this work. (orig.)

  5. Evaluation of the osteo-inductive potential of hollow three-dimensional magnesium-strontium substitutes for the bone grafting application

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mei [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Department of Orthopedics, Guangdong Key Lab of Orthopaedic Technology and Implant Materials, Guangzhou General Hospital of Guangzhou military command, Guangzhou 510010 (China); Yang, Xuan [Guangzhou University of Chinese Medicine, Guangzhou 510405 (China); Wang, Weidan [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang, Yu [Department of Orthopedics, Guangdong Key Lab of Orthopaedic Technology and Implant Materials, Guangzhou General Hospital of Guangzhou military command, Guangzhou 510010 (China); Wan, Peng, E-mail: pwan@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Yang, Ke [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Han, Yong, E-mail: yonghan@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2017-04-01

    Regeneration of bone defects is a clinical challenge that usually necessitates bone grafting materials. Limited bone supply and donor site morbidity limited the application of autografting, and improved biomaterials are needed to match the performance of autografts. Osteoinductive materials would be the perfect candidates for achieving this task. Strontium (Sr) is known to encourage bone formation and also prevent osteoporosis. Such twin requirements have motivated researchers to develop Sr-substituted biomaterials for orthopedic applications. The present study demonstrated a new concept of developing biodegradable and hollow three-dimensional magnesium-strontium (Mg−Sr) devices for grafting with their clinical demands. The microstructure and performance of Mg−Sr devices, in vitro degradation and biological properties including in vitro cytocompatibility and osteoinductivity were investigated. The results showed that our Mg−Sr devices exhibited good cytocompatibility and osteogenic effect. To further investigate the underlying mechanisms, RT-PCR and Western Blotting assays were taken to analyze the expression level of osteogenesis-related genes and proteins, respectively. The results showed that our Mg−Sr devices could both up-regulate the genes and proteins expression of the transcription factors of Runt-related transcription factor 2 (RUNX2) and Osterix (OSX), as well as alkaline phosphatase (ALP), Osteopontin (OPN), Collagen I (COL I) and Osteocalcin (OCN) significantly. Taken together, our innovation presented in this work demonstrated that the hollow three-dimensional Mg−Sr substitutes had excellent biocompatibility and osteogenesis and could be potential candidates for bone grafting for future orthopedic applications. - Highlights: • Novel biodegradable Mg−Sr bone substitutes with the hollow and marginal design was fabricated • The Mg−Sr substitutes exhibited excellent cyto-compatibility and osteo-inductivity effects • The osteo-inductivity

  6. Get Enough Calcium

    Science.gov (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... women, don't get enough calcium. How much calcium do I need every day? Women: If you ...

  7. Calcium - urine

    Science.gov (United States)

    ... Female urinary tract Male urinary tract Calcium urine test References Bringhurst FR, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology . 13th ed. Philadelphia, PA: Elsevier; ...

  8. Formation of calcium phosphate layer on ceramics with different reactivities

    International Nuclear Information System (INIS)

    Ribeiro, C.; Rigo, E.C.S.; Sepulveda, P.; Bressiani, J.C.; Bressiani, A.H.A.

    2004-01-01

    Biphasic ceramic samples of different biological reactivity are prepared by using hydroxyapatite (HAp) and tricalcium phosphate (TCP) in various ratios. Different parameters for sintering in an air atmosphere furnace were defined after dilatometric studies. An increased densification with decreased TCP content was observed. The sintered bodies were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dissolution kinetics and in vitro reactivity were investigated using simulated body fluid (SBF) at 37 deg. C for a maximum period of 3 weeks. The surfaces of the ceramics were analyzed by Fourier transform infrared spectroscopy (FTIR) and SEM in order to observe the formation of a calcium phosphate layer, which indicates the samples bioactivity. Dissolution in SBF demonstrated that layers with different kinetics on the samples surface were formed during the immersion period. The biphasic ceramics show bioactive behavior, even if the resorbable TCP is incorporated

  9. A study on MR signal intensity of calcifications according to calcium concentration and compound

    International Nuclear Information System (INIS)

    Chang, Sun Ae; Kim, Jae Hyoung; Chung, Sung Hoon

    1996-01-01

    The signal of intracranial calcification on magnetic resonance (MR) imaging has been known to be variable. The purpose of this study was to evaluate the MR signal of calcifications according to calcium concentration and compound. T1-weighted, proton density and T2-weighted images were obtained in phantoms with various conposition of calcium carbonate and calcium phosphate. The signal intensities and T1/T2 relaxation times were measured and analyzed according to calcium concentration and compound. The configurations of calcium particles were evaluated by scanning electron microscopy. The signal intensity of calcium carbonate on T1-weighted images gradually decreased as the concentration increased, while that of calcium phosphate showed a biphasic curve with a peak intensity at 0.2g/ml. The signal intensity of both calcium phosphate decreased up to 0.2g/ml and then remained constant. The T2 relaxation time of both calcium compounds decreased in a similar fashion with increasing concentration, Calcium phosphate showed larger surface area on scanning electron microscope. Calcifications show variable MR signal due to difference of T1 and T2 relaxation times according to calcium concentration and compound. Large surface area of calcium particle might cause shortening of T1 relaxation time leading to high signal on T1-weighted image. Understanding of these findings will help interpretation of MR images more precisely

  10. Cell–material interactions on biphasic polyurethane matrix

    Science.gov (United States)

    Dicesare, Patrick; Fox, Wade M.; Hill, Michael J.; Krishnan, G. Rajesh; Yang, Shuying; Sarkar, Debanjan

    2013-01-01

    Cell–matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell–matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

  11. A New Biphasic Dicalcium Silicate Bone Cement Implant

    Directory of Open Access Journals (Sweden)

    Fausto Zuleta

    2017-07-01

    Full Text Available This study aimed to investigate the processing parameters and biocompatibility of a novel biphasic dicalcium silicate (C2S cement. Biphasic α´L + β-C2Sss was synthesized by solid-state processing, and was used as a raw material to prepare the cement. In vitro bioactivity and biocompatibility studies were assessed by soaking the cement samples in simulated body fluid (SBF and human adipose stem cell cultures. Two critical-sized defects of 6 mm Ø were created in 15 NZ tibias. A porous cement made of the high temperature forms of C2S, with a low phosphorous substitution level, was produced. An apatite-like layer covered the cement’s surface after soaking in SBF. The cell attachment test showed that α´L + β-C2Sss supported cells sticking and spreading after 24 h of culture. The cement paste (55.86 ± 0.23 obtained higher bone-to-implant contact (BIC percentage values (better quality, closer contact in the histomorphometric analysis, and defect closure was significant compared to the control group (plastic. The residual material volume of the porous cement was 35.42 ± 2.08% of the initial value. The highest BIC and bone formation percentages were obtained on day 60. These results suggest that the cement paste is advantageous for initial bone regeneration.

  12. Analysis of a biphase-based servo format for hard-disk drives

    NARCIS (Netherlands)

    Makinwa, K.A.A.; Bergmans, J.W.M.; Voorman, J.O.

    2000-01-01

    Biphase modulation in an embedded-servo format for hard-disk drives is investigated. It is shown that for biphase, at the low linear densities typical of servo information, near-maximum-likelihood performance can be attained by a simple bit detector consisting of a full-response linear equalizer and

  13. Hybrid calcium phosphate coatings for implants

    Science.gov (United States)

    Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

    2016-08-01

    Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

  14. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.

    1984-01-01

    Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture,

  15. Generic Model-Based Tailor-Made Design and Analysis of Biphasic Reaction Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata

    systems have a broad range of application, such as the manufacture of petroleum based chemicals, pharmaceuticals, and agro-bio products. Major considerations in the design and analysis of biphasic reaction systems are physical and chemical equilibria, kinetic mechanisms, and reaction rates. The primary...... contribution of this thesis is the development of a systematic modelling framework for the biphasic reaction system. The developed framework consists of three modules describing phase equilibria, reactions and mass transfer, and material balances of such processes. Correlative and predictive thermodynamic......Biphasic reaction systems are composed of immiscible aqueous and organic liquid phases where reactants, products, and catalysts are partitioned. These biphasic conditions point to novel synthesis paths, higher yields, and faster reactions, as well as facilitate product separation. The biphasic...

  16. Strontium (Sr) and silver (Ag) loaded nanotubular structures with combined osteoinductive and antimicrobial activities.

    Science.gov (United States)

    Cheng, Hao; Xiong, Wei; Fang, Zhong; Guan, Hanfeng; Wu, Wei; Li, Yong; Zhang, Yong; Alvarez, Mario Moisés; Gao, Biao; Huo, Kaifu; Xu, Jiangwen; Xu, Na; Zhang, Chengcheng; Fu, Jijiang; Khademhosseini, Ali; Li, Feng

    2016-02-01

    Two frequent problems are associated with the titanium surfaces of bone/dental implants: lack of native tissue integration and associated infection. These problems have prompted a significant body of research regarding the modification of these surfaces. The present study describes a hydrothermal treatment for the fabrication of strontium (Sr) and silver (Ag) loaded nanotubular structures with different tube diameters on titanium surfaces. The Sr loading from a Sr(OH)2 solution was regulated by the size of the inner diameter of the titanium nanotubes (NT) (30nm or 80nm, formed at 10V or 40V, respectively). The quantity of Ag was adjusted by immersing the samples in 1.5 or 2.0M AgNO3 solutions. Sr and Ag were released in a controllable and prolonged matter from the NT-Ag.Sr samples, with negligible cytotoxicity. Prominent antibacterial activity was observed due to the release of Ag. Sr incorporation enhanced the initial cell adhesion, migration, and proliferation of preosteoblast MC3T3-E1 cells. Sr release also up-regulated the expression of osteogenic genes and induced mineralization, as suggested by the presence of more mineralized calcium nodules in cells cultured on NT-Ag.Sr surfaces. In vivo experiments showed that the Sr-loaded samples accelerated the formation of new bone in both osteoporosis and bone defect models, as confirmed by X-ray, Micro-CT evaluation, and histomorphometric analysis of rats implanted with NT-Ag.Sr samples. The antibacterial activity and outstanding osteogenic properties of NT-Ag.Sr samples highlight their excellent potential for use in clinical applications. Two frequent problems associated with Ti surfaces, widely used in orthopedic and dental arenas, are their lack of native tissue integration and risk of infection. We describe a novel approach for the fabrication of strontium (Sr) and silver (Ag) loaded nanotubular structures on titanium surfaces. A relevant aspect of this work is the demonstration of long-lasting and controllable

  17. Biphasic 201thallium scintgraphy after dipyridamole in mitral valve diseases

    International Nuclear Information System (INIS)

    Schmoliner, R.; Dudczak, R.; Kronik, G.; Moesslacher, H.; Kletter, K.; Frischauf, H.

    1980-01-01

    The results of biphasic 201 thallium scintigraphy after dipyridamole i.v. could neither prove nor exclude the presence of small focal lesions in the myocardium of 17 patients with mitral valve diseases. The frequent finding of a decrease in activity in the anterolateral myocardium is probably due to a relative increase in activity in the region of the inferior wall with superimposed areas of the papillary muscle and right ventricular myocardium. If the right ventricle is visualized in stress- or redistribution images, an increase in mean pulmonary artery pressure can be accepted. According to Cohen's criteria, a grade 2 or 3 virtually proves the existence of pulmonary hypertension, a grade 1 makes this finding rather probable. The possibility of pulmonary hypertension can not be excluded if the right ventricular myocardium is not visualized. (orig.) [de

  18. Biphasic growth of orbital volume in Chinese children.

    Science.gov (United States)

    Wei, Nan; Bi, Hua; Zhang, Bin; Li, Xue; Sun, Fengyuan; Qian, Xuehan

    2017-09-01

    The aim of this study was to map out the developmental curve of the orbital volume of Chinese children aged 1-15 years. CT scanning was performed on 109 children and the orbital volume, interlateral orbital rim distance (IORD), and extent of exophthalmos were measured on the CT images and plotted against age. The development of the orbit structure followed a biphasic pattern. The first growth phase was before 3 years and the second growth phase was between 7 years and 12 years of age. The growth speed in the first phase was about 3 times that of the second one (first vs second phase: 2.28 cm 3 /year vs 0.67 cm 3 /year for orbital volume, 5.01 mm/year vs 1.57 mm/year for IORD, 1.29 mm/year vs 0.42 mm/year for the exophthalmos). During development, there was no significant difference between the left and right orbits. There was no significant difference between boys and girls before 12 years of age. However, after 12 years of age, boys had significantly larger orbital volumes (22.16±2.28 cm 3 /year vs 18.57±1.16 cm 3 /year, pChinese children, the development of orbital volume follows a biphasic pattern and a sex difference becomes significant after the age of 12 years. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  19. [Fabrication of porous poly lactic acid-bone matrix gelatin composite bioactive material and its osteoinductive activity].

    Science.gov (United States)

    Zhang, Yumin; Li, Baoxing; Li, Ji

    2007-02-01

    To fabricate a novel porous bioactive composite biomaterial consisting of poly lactic acid (PLA)-bone matrix gelatin (BMG) by using the supercritical carbon dioxide fluid technique (SC-CO2) and to evaluate its osteoinductive activity. The cortical bones selected from healthy adult donors were processed into BMG by the defatting, demineralizing, and deproteinizing processes. PLA and BMG were mixed at a volume radio of 3 : 1; then, the PLA-BMG mixed material and the pure PLA material were respectively placed in the supercritical carbon dioxide reaction kettles, and were respectively added by the NaCl particles 100-200 microm in diameter for the porosity of the materials so that the porous PLA-BMG composite material and the porous PLA composite material could be formed. The mouse osteoblast-like MC3T3-E1 cells were cultured in the dulbecco's modified eagle medium (DMEM) supplemented with 10% fetal bovine serum. Then, 20 microl of the MC3T3-E1 cell suspensions containing 2 X 10(6) cells /ml were delivered into the culturing plate (24 wells/plate) made of the different materials, which were co-cultured for 2 weeks. In the PLA-BMG group, 100 microg of the crushed PLA-BMG material was contained in each well; in the PLA group, 100 microg of the crushed PLA material was contained in each well; and in the DMEM group, only DMEM was contained, which served as the control group. There were 6 wells in each group. The quantitative analysis on the calcification area was performed by the staining of the alizarin red S. The co-cultured cells were harvested and lysated in 1 ml of 0. 2% Nonidet P-40 by the ultrasonic lysating technique. Then, the ALP activity and the Ca content were measured according to the illuminations of the reagent kits. The porous PLA-BMG composite material showed a good homological porosity with a pore diameter of 50-150 microm and a good connectivity between the pores. The ALP activity, the Ca content, and the calcification area were significantly greater in

  20. TSDC and impedance spectroscopy measurements on hydroxyapatite, β-tricalcium phosphate and hydroxyapatite/β-tricalcium phosphate biphasic bioceramics

    Science.gov (United States)

    Prezas, P. R.; Melo, B. M. G.; Costa, L. C.; Valente, M. A.; Lança, M. C.; Ventura, J. M. G.; Pinto, L. F. V.; Graça, M. P. F.

    2017-12-01

    Bone grafting and surgical interventions related with orthopaedic disorders consist in a big business, generating large revenues worldwide every year. There is a need to replace the biomaterials that currently still dominate this market, i.e., autografts and allografts, due to their disadvantages, such as limited availability, need for additional surgeries and diseases transmission possibilities. The most promising replacement materials are biomaterials with bioactive properties, such as the calcium phosphate-based bioceramics group. The bioactivity of these materials, i.e., the rate at which they promote the growth and directly bond with the new host biological bone, can be enhanced through their electrical polarization. In the present work, the electrical polarization features of pure hydroxyapatite (Hap), pure β-tricalcium phosphate (β-TCP) and biphasic hydroxyapatite/β-tricalcium phosphate composites (HTCP) were analyzed by measuring thermally stimulated depolarization currents (TSDC). The samples were thermoelectrically polarized at 500 °C under a DC electric field with a magnitude of 5 kV/cm. The biphasic samples were also polarized under electric fields with different magnitudes: 2, 3, 4 and 5 kV/cm. Additionally, the depolarization processes detected in the TSDC measurements were correlated with dielectric relaxation processes observed in impedance spectroscopy (IS) measurements. The results indicate that the β-TCP crystalline phase has a considerable higher ability to store electrical charge compared with the Hap phase. This indicates that it has a suitable composition and structure for ionic conduction and establishment of a large electric charge density, providing great potential for orthopaedic applications.

  1. Biphasic synaptic Ca influx arising from compartmentalized electrical signals in dendritic spines.

    Directory of Open Access Journals (Sweden)

    Brenda L Bloodgood

    2009-09-01

    Full Text Available Excitatory synapses on mammalian principal neurons are typically formed onto dendritic spines, which consist of a bulbous head separated from the parent dendrite by a thin neck. Although activation of voltage-gated channels in the spine and stimulus-evoked constriction of the spine neck can influence synaptic signals, the contribution of electrical filtering by the spine neck to basal synaptic transmission is largely unknown. Here we use spine and dendrite calcium (Ca imaging combined with 2-photon laser photolysis of caged glutamate to assess the impact of electrical filtering imposed by the spine morphology on synaptic Ca transients. We find that in apical spines of CA1 hippocampal neurons, the spine neck creates a barrier to the propagation of current, which causes a voltage drop and results in spatially inhomogeneous activation of voltage-gated Ca channels (VGCCs on a micron length scale. Furthermore, AMPA and NMDA-type glutamate receptors (AMPARs and NMDARs, respectively that are colocalized on individual spine heads interact to produce two kinetically and mechanistically distinct phases of synaptically evoked Ca influx. Rapid depolarization of the spine triggers a brief and large Ca current whose amplitude is regulated in a graded manner by the number of open AMPARs and whose duration is terminated by the opening of small conductance Ca-activated potassium (SK channels. A slower phase of Ca influx is independent of AMPAR opening and is determined by the number of open NMDARs and the post-stimulus potential in the spine. Biphasic synaptic Ca influx only occurs when AMPARs and NMDARs are coactive within an individual spine. These results demonstrate that the morphology of dendritic spines endows associated synapses with specialized modes of signaling and permits the graded and independent control of multiple phases of synaptic Ca influx.

  2. Calcium blood test

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003477.htm Calcium blood test To use the sharing features on this page, please enable JavaScript. The calcium blood test measures the level of calcium in the blood. ...

  3. Calcium source (image)

    Science.gov (United States)

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  4. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  5. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Products that contain calcium carbonate are certain: Antacids (Tums, Chooz) Mineral supplements Hand lotions Vitamin and mineral supplements Other products may also contain ...

  6. Calcium and bones (image)

    Science.gov (United States)

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  7. Calcium hydroxide poisoning

    Science.gov (United States)

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  8. Paired associative stimulation targeting the tibialis anterior muscle using either mono or biphasic transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Mrachacz-Kersting, Natalie; Stevenson, Andrew James Thomas

    2017-01-01

    Paired associative stimulation (PAS) protocols induce plastic changes within the motor cortex. The objectives of this study were to investigate PAS effects targeting the tibialis anterior (TA) muscle using a biphasic transcranial magnetic stimulation (TMS) pulse form and, to determine whether...... a reduced intensity of this pulse would lead to significant changes as has been reported for hand muscles using a monophasic TMS pulse. Three interventions were investigated: (1) suprathreshold PAbi-PAS (n = 11); (2) suprathreshold PAmono-PAS (n = 11) where PAS was applied using a biphasic or monophasic......% for subthreshold PAbi-PAS. PAS using a biphasic pulse form at subthreshold intensities induces similar effects to conventional PAS....

  9. Drug-Loadable Calcium Alginate Hydrogel System for Use in Oral Bone Tissue Repair.

    Science.gov (United States)

    Chen, Luyuan; Shen, Renze; Komasa, Satoshi; Xue, Yanxiang; Jin, Bingyu; Hou, Yepo; Okazaki, Joji; Gao, Jie

    2017-05-06

    This study developed a drug-loadable hydrogel system with high plasticity and favorable biological properties to enhance oral bone tissue regeneration. Hydrogels of different calcium alginate concentrations were prepared. Their swelling ratio, degradation time, and bovine serum albumin (BSA) release rate were measured. Human periodontal ligament cells (hPDLCs) and bone marrow stromal cells (BMSCs) were cultured with both calcium alginate hydrogels and polylactic acid (PLA), and then we examined the proliferation of cells. Inflammatory-related factor gene expressions of hPDLCs and osteogenesis-related gene expressions of BMSCs were observed. Materials were implanted into the subcutaneous tissue of rabbits to determine the biosecurity properties of the materials. The materials were also implanted in mandibular bone defects and then scanned using micro-CT. The calcium alginate hydrogels caused less inflammation than the PLA. The number of mineralized nodules and the expression of osteoblast-related genes were significantly higher in the hydrogel group compared with the control group. When the materials were implanted in subcutaneous tissue, materials showed favorable biocompatibility. The calcium alginate hydrogels had superior osteoinductive bone ability to the PLA. The drug-loadable calcium alginate hydrogel system is a potential bone defect reparation material for clinical dental application.

  10. Effect of Calcium Phosphate Coating and rhBMP-2 on Bone Regeneration in Rabbit Calvaria Using Poly(propylene fumarate) Scaffolds

    Science.gov (United States)

    2015-01-07

    13,14], dental implants [15,16] and screws for fracture fixation [17,18]. These coatings provide a bone-like mineral matrix that simulates the in... calculus formation. Am J Dent 1999;12:65–71. [27] Bouler J-M, LeGeros RZ, Daculsi G. Biphasic calcium phosphates: influence of three synthesis

  11. Calcium in Urine Test

    Science.gov (United States)

    ... K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2 nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Calcium, Serum; Calcium and Phosphates, Urine; ...

  12. Transcellular transport of calcium

    Energy Technology Data Exchange (ETDEWEB)

    Terepka, A R; Coleman, J R; Armbrecht, H J; Gunter, T E

    1976-01-01

    Studies of two calcium transporting epithelia, embryonic chick chorioallantoic membrane and the small intestine of rat and chick, have strongly suggested that the transfer of calcium across a cell involves processes distinctly different from intracellular calcium ion regulation. In the proposed model, transcellular calcium transport is considered as a specialized process developed only by certain cells in those tissues charged with bulk transfer of calcium. The overall effect of the endocytotic mechanism is bulk calcium movement across a cell, protection of mitochondria from exposure to high concentrations of calcium, and the avoidance of wide and potentially toxic fluctuations in cytosol ionic calcium levels. (MFB)

  13. A microstructural study of the degradation and calcium release from hydroxyapatite-calcium oxide ceramics made by infiltration.

    Science.gov (United States)

    Zhang, Qinghao; Schmelzer, Eva; Gerlach, Jörg C; Nettleship, Ian

    2017-04-01

    Hydroxyapatite pellets, partially densified in a low-temperature heat treatment, were infiltrated with calcium nitrate solution followed by in-situ precipitation of Ca(OH) 2 and CaCO 3 . The infiltrated bodies were then densified to high relative density and the calcium carbonate transformed to calcium oxide during sintering and resulted in biphasic hydroxyapatite-CaO ceramics. This work investigated the influence of the infiltration on surface morphology, weight change, and microstructural-level degradation caused by exposure to saline at pH=7.4 and a temperature of 20°C. The CaO rendered the materials more susceptible to degradation, and released calcium into the saline faster than single phase, calcium deficient hydroxyapatite (HA) that were used as a control. In consequence, these ceramics could be used to release calcium into the culture microenvironments of bone tissue or bone marrow cells next to a scaffold surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. The Phosphodiesterase 4 Inhibitor Prevents Antigen-induced Biphasic Nasal Obstruction in Brown Norway Rats

    Directory of Open Access Journals (Sweden)

    Hirokazu Kawasaki

    2005-01-01

    Conclusions: The present study provides a simple model of allergic biphasic nasal obstruction in BN rats, and also suggests that the PDE4 inhibitor may alleviate nasal obstruction in patients with allergic rhinitis.

  15. Generation of useful energy from process fluids using the biphase turbine

    Science.gov (United States)

    Helgeson, N. L.

    1981-01-01

    The six largest energy consuming industries in the United States were surveyed to determine the energy savings that could result from applying the Biphase turbine to industrial process streams. A national potential energy savings of 58 million barrels of oil per year (technical market) was identified. This energy is recoverable from flashing gas liquid process streams and is separate and distinct from exhaust gas waste heat recovery. The industries surveyed in this program were the petroleum chemical, primary metals, paper and pulp, stone-clay-glass, and food. It was required to determine the applicability of the Biphase turbine to flashing operations connected with process streams, to determine the energy changes associated with these flashes if carried out in a Biphase turbine, and to determine the suitability (technical and economical feasibility) of applying the Biphase turbine to these processes.

  16. Biphasic cuirass ventilation is better than bag-valve mask ventilation for resuscitation following organophosphate poisoning

    Directory of Open Access Journals (Sweden)

    Ilan Gur

    2015-01-01

    Conclusions: The noninvasive, easy-to-operate Biphasic Cuirass Ventilation device was effective in reducing OP-induced mortality and might be advantageous in an organophosphate mass casualty event. This finding should be validated in further investigations.

  17. 2-N, 6-O-sulfated chitosan-assisted BMP-2 immobilization of PCL scaffolds for enhanced osteoinduction

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Lingyan [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3168 (Australia); Department of Prosthodontics, College of Stomatology, Ninth People' s Hospital, School of Medicine, Shanghai Jiao Tong University, 639 Zhizaoju Road, Shanghai 200011 (China); Yu, Yuanman [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Wang, Jing, E-mail: biomatwj@163.com [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Werkmeister, Jerome A [CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3168 (Australia); McLean, Keith M, E-mail: Keith.McLean@csiro.au [CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3168 (Australia); Liu, Changsheng, E-mail: liucs@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China)

    2017-05-01

    The aim of this study was to develop a 2-N, 6-O-sulfated chitosan (26SCS) modified electrospun fibrous PCL scaffold for bone morphogenetic protein-2 (BMP-2) delivery to improve osteoinduction. The PCL scaffold was modified by an aminolysis reaction using ethylenediamine (ED) and 26SCS was immobilized via electrostatic interactions (PCL-N-S). Scaffolds were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. In vitro BMP-2 adsorption and release kinetics indicated that modified PCL-N-S scaffolds showed higher levels of binding of BMP-2 (about 30–100 times), moderative burst release (about one third), and prolonged releasing time compared to the unmodified PCL scaffold. The bioactivity of released BMP-2 determined by alkaline phosphatase (ALP) activity assay was maintained and improved 8– 12 times with increasing concentration of immobilized 26SCS on the scaffolds. In vitro studies demonstrated that bone marrow mesenchymal stem cells (BMSCs) attached more readily to the PCL-N-S scaffolds with increased spreading. In conclusion, 26SCS modified PCL scaffolds can be a potent system for the sustained and bioactive delivery of BMP-2. - Graphical abstract: Limited self-regenerating capacity of human body makes the reconstruction of critical size bone defect a significant challenge. Although bone morphogenetic protein-2 (BMP-2) is an important differentiation factor inducing bone regeneration, it's short half-life in vivo and potent side effect at high dosage still show lots of concerns in the clinical use. Herein, modification of electrospun PCL scaffolds was presented through immobilizing of sulfated chitosan (26SCS). The modified scaffolds effectively improve the binding capacity of BMP-2 and exhibited an enhanced bioactivity and sustained release in vitro. Thus, the use of 26SCS modified PCL scaffolds combined with BMP-2 could be a useful scaffold for tissue

  18. Biphasic oxidation of oxy-hemoglobin in bloodstains.

    Directory of Open Access Journals (Sweden)

    Rolf H Bremmer

    Full Text Available BACKGROUND: In forensic science, age determination of bloodstains can be crucial in reconstructing crimes. Upon exiting the body, bloodstains transit from bright red to dark brown, which is attributed to oxidation of oxy-hemoglobin (HbO(2 to met-hemoglobin (met-Hb and hemichrome (HC. The fractions of HbO(2, met-Hb and HC in a bloodstain can be used for age determination of bloodstains. In this study, we further analyze the conversion of HbO(2 to met-Hb and HC, and determine the effect of temperature and humidity on the conversion rates. METHODOLOGY: The fractions of HbO(2, met-Hb and HC in a bloodstain, as determined by quantitative analysis of optical reflectance spectra (450-800 nm, were measured as function of age, temperature and humidity. Additionally, Optical Coherence Tomography around 1300 nm was used to confirm quantitative spectral analysis approach. CONCLUSIONS: The oxidation rate of HbO(2 in bloodstains is biphasic. At first, the oxidation of HbO(2 is rapid, but slows down after a few hours. These oxidation rates are strongly temperature dependent. However, the oxidation of HbO(2 seems to be independent of humidity, whereas the transition of met-Hb into HC strongly depends on humidity. Knowledge of these decay rates is indispensable for translating laboratory results into forensic practice, and to enable bloodstain age determination on the crime scene.

  19. Comparison between FEBio and Abaqus for biphasic contact problems.

    Science.gov (United States)

    Meng, Qingen; Jin, Zhongmin; Fisher, John; Wilcox, Ruth

    2013-09-01

    Articular cartilage plays an important role in the function of diarthrodial joints. Computational methods have been used to study the biphasic mechanics of cartilage, and Abaqus has been one of the most widely used commercial software packages for this purpose. A newly developed open-source finite element solver, FEBio, has been developed specifically for biomechanical applications. The aim of this study was to undertake a direct comparison between FEBio and Abaqus for some practical contact problems involving cartilage. Three model types, representing a porous flat-ended indentation test, a spherical-ended indentation test, and a conceptual natural joint contact model, were compared. In addition, a parameter sensitivity study was also performed for the spherical-ended indentation test to investigate the effects of changes in the input material properties on the model outputs, using both FEBio and Abaqus. Excellent agreement was found between FEBio and Abaqus for all of the model types and across the range of material properties that were investigated.

  20. Biphasic interactions between a cationic dendrimer and actin.

    Science.gov (United States)

    Ruenraroengsak, Pakatip; Florence, Alexander T

    2010-12-01

    Gene delivery systems face the problem not only of the route toward the cell and tissues in question, but also of the molecularly crowded environment of both the cytoplasm and the nucleus itself. One of the physical barriers in the cytoplasm for diffusing nanoparticles is an actin network. Here, we describe the finding that a self-fluorescent sixth generation cationic dendrimer (6 nm in diameter) interacts reversibly and possibly electrostatically with actin filaments in vitro. Not only does this interaction slow the diffusion of the dendrimer but it also affects actin polymerization in a biphasic manner. At low concentrations the dendrimer behaves like a G-binding actin protein, retarding actin polymerization, whereas at high concentrations the dendrimer acts as a nucleating protein accelerating the polymerization. Thus in vivo the diffusion of a dendrimer carrier such as this has both physical and chemical elements: by decreasing polymerization it might accelerate its own transport, and by enhancing actin polymerization retard it. This finding suggests that such a dendrimer may have a role as an anticancer agent through its inhibitory effect on actin polymerization.

  1. Aqueous biphasic systems involving alkylsulfate-based ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Deive, Francisco J. [Instituto de Tecnologia Quimica e Biologica, UNL, Av. Republica, Apartado 127, 2780-901 Oeiras (Portugal); Department of Chemical Engineering, University of Vigo, P.O. Box 36310, Vigo (Spain); Rodriguez, Ana [Department of Chemical Engineering, University of Vigo, P.O. Box 36310, Vigo (Spain); Marrucho, Isabel M., E-mail: imarrucho@itqb.unl.pt [Instituto de Tecnologia Quimica e Biologica, UNL, Av. Republica, Apartado 127, 2780-901 Oeiras (Portugal); Rebelo, Luis P.N. [Instituto de Tecnologia Quimica e Biologica, UNL, Av. Republica, Apartado 127, 2780-901 Oeiras (Portugal)

    2011-11-15

    Highlights: > K{sub 3}PO{sub 4}, K{sub 2}CO{sub 3}, Na{sub 2}CO{sub 3}, and (NH{sub 4}){sub 2}SO{sub 4} act as phase promoter in aqueous solutions of ILs. > Remarkable influence of alkyl-chain length on solubility curves of alkylsulfate-based ILs. > Merchuck correlation was used for describing these systems. > {Delta}S{sub hyd} and Hofmeister series were used to discuss the different salting out effects. - Abstract: The specific effects of K{sub 3}PO{sub 4}, K{sub 2}CO{sub 3}, Na{sub 2}CO{sub 3}, and (NH{sub 4}){sub 2}SO{sub 4}, as high charge-density inorganic salts and thus inducers of the formation of aqueous biphasic systems (ABS) containing several ethyl-methylimidazolium alkylsulfate ionic liquids, C{sub 2}MIM C{sub n}SO{sub 4} (n = 2, 4, 6, or 8), have been assessed at T = 298.15 K. The results are analyzed in the light of the Hofmeister series. The influence of different alkyl chain lengths in the anion, together with the ability of the selected inorganic salts to induce the formation of ABS, is discussed. Phase diagrams have been determined through turbidimetry, including tie lines assignments from mass phase ratios according to the lever - arm rule. The Merchuck equation was satisfactorily used to correlate the solubility curve.

  2. Biphasically Modulating the Activity of Carboxypeptidase G2 with Ultrasound

    Directory of Open Access Journals (Sweden)

    Wanying Ma

    2017-07-01

    Full Text Available Background/Aims: Carboxypeptidase G2 (CPG2 has been used for cancer prodrug therapy to realize the targeted release of active drugs, but there yet lacks a means to modulate the CPG2 activity. Here ultrasound was used to modulate the CPG2 activity. Methods: The activity of insonated CPG2 was determined, and then underlying biochemical (i.e., monomer, dimer and conformation and ultrasonic (i.e., heat and cavitation mechanisms were explored. Results: Ultrasound (1.0 MHz increased or decreased the enzymatic activity; the activity decreased as zero- or first-order kinetics, depending on the intensity. L1 (10 W/cm2 for 200 s improved the activity via increasing the specific activity. L2 or L3 (20 W/cm2 for 1200 or 3000 s decreased the activity via disassembling the dimer, degrading the monomer, inducing glycosylation, transforming conformation and decreasing the specific activity. An increase or a slight decrease of activity attributable to 10 W/cm2 was reversible, but the activity decrease due to 20 W/cm2 was irreversible. The enzymatic modulation was realized via cavitation. Conclusion: Ultrasound can biphasically modulate the CPG2 activity, and can be employed in the CPG2-prodrug therapy to adjust the release and moles of active drugs.

  3. A biphasic model for bleeding in soft tissue

    Science.gov (United States)

    Chang, Yi-Jui; Chong, Kwitae; Eldredge, Jeff D.; Teran, Joseph; Benharash, Peyman; Dutson, Erik

    2017-11-01

    The modeling of blood passing through soft tissues in the body is important for medical applications. The current study aims to capture the effect of tissue swelling and the transport of blood under bleeding or hemorrhaging conditions. The soft tissue is considered as a non-static poro-hyperelastic material with liquid-filled voids. A biphasic formulation effectively, a generalization of Darcy's law-is utilized, treating the phases as occupying fractions of the same volume. The interaction between phases is captured through a Stokes-like friction force on their relative velocities and a pressure that penalizes deviations from volume fractions summing to unity. The soft tissue is modeled as a hyperelastic material with a typical J-shaped stress-strain curve, while blood is considered as a Newtonian fluid. The method of Smoothed Particle Hydrodynamics is used to discretize the conservation equations based on the ease of treating free surfaces in the liquid. Simulations of swelling under acute hemorrhage and of draining under gravity and compression will be demonstrated. Ongoing progress in modeling of organ tissues under injuries and surgical conditions will be discussed.

  4. Calcium sensing in exocytosis

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wu, Bingbing; Han, Weiping

    2012-01-01

    an increase in intracellular calcium levels. Besides the triggering role, calcium signaling modulates the precise amount and kinetics of vesicle release. Thus, it is a central question to understand the molecular machineries responsible for calcium sensing in exocytosis. Here we provide an overview of our...... current understanding of calcium sensing in neurotransmitter release and hormone secretion....

  5. Calcium fluoride

    International Nuclear Information System (INIS)

    King, C.W.; Nestor, O.H.

    1989-01-01

    A new process for producing large, single, oriented crystals of calcium fluoride (CaF 2 ) has been developed which overcomes the limitations of current growing methods. This process has been reduced to practice and has yielded oriented crystals 17.5 x 17.5 x 5 cm 3 . Currently nearing completion is a system for producing 35 x 35 x 7.5 cm 3 single crystals. A scale up to one-meter-square is considered feasible. This crystal growing process makes possible the fabrication of very large CaF 2 windows. Suitability for very high power lasers, however, requires attention to properties beyond mere size. A process to generate higher purity growth stock (starting material) was also developed. The additional purification of the growth stock contributes to lower bulk absorption, the absence of color centers and increased radiation hardness. Also identified were several specific impurities which correlate with radiation hardness. A correlation was found between color centers induced by laser radiation and ionizing radiation. Other CaF 2 crystal properties such as tensile strength, absorption and laser damage thresholds were studied and are discussed

  6. Production and characterization of setting hydraulic cements based on calcium phosphate

    International Nuclear Information System (INIS)

    Oliveira, Luci C. de; Rigo, Eliana C.S.; Santos, Luis A dos; Boschi, Anselmo Ortega; Carrodeguas, Raul G.

    1997-01-01

    Setting hydraulic cements based on calcium phosphate has risen great interest in scientific literature during recent years due to their total bio compatibility and to the fact that they harden 'in situ', providing easy handling and adaptation to the shape and dimensions of the defect which requires correction, differently from the predecessors, the calcium phosphate ceramics (Hydroxy apatite, β-tri calcium phosphate, biphasic, etc) in the shape of dense or porous blocks and grains. In the work, three calcium-phosphate cement compositions were studied. The resulting compositions were characterized according to the following aspects: setting times, pH, mechanical resistance, crystalline phases, microstructure and solubility in SBF (Simulated Body Fluid). The results show a potential use for the compositions. (author)

  7. The biphasic effect of triiodothyronine compared to bone resorbing effect of PTH on bone modelling of mouse long bone in vitro

    International Nuclear Information System (INIS)

    Soskolne, W.A.; Schwartz, Z.; Goldstein, M.; Ornoy, A.

    1990-01-01

    To examine the effects of T3 on fetal long bone modelling the radii and ulnae of 16 day old fetal mice were grown in vitro for two days. Their growth, mineralization, and resorption were assessed by measuring diaphyseal length, calcium and phosphorus content, hydroxyproline content, and the release of incorporated 45 Ca. The effects of T3 were compared to the effects of 1-34 PTH, a known resorbing agent, on the same system. Devitalized bones were used as a control. The results showed that T3 had a biphasic effect. At high concentrations (10(-5) M-10(-6) M) T3 inhibited the growth of the bones as indicated by their diaphyseal length and hydroxyproline content. Calcium and phosphorus content were significantly decreased while 45 Ca release was increased. Similar effects were also found after the addition of 1-34 PTH to the media. However, T3, at lower concentrations (10(-7) M-10(-9) M), stimulated the growth and calcification of the bones as indicated by an increase in diaphyseal length and the hydroxyproline, calcium, and phosphorus content. 45 Ca release was significantly decreased at these concentrations. Neither T3 nor 1-34 PTH affected devitalized bones in the same system. The results suggest that at physiological concentrations, T3 has a direct, anabolic effect on bone, which may explain its major role in the growth process of various species. At high doses, however, T3 stimulates bone resorption in a way similar to PTH

  8. Design and evaluation of lornoxicam bilayered tablets for biphasic release

    Directory of Open Access Journals (Sweden)

    Songa Ambedkar Sunil

    2012-12-01

    Full Text Available The objective of the present investigation was to develop bilayered tablets of lornoxicam to achieve biphasic release pattern. A bilayered tablet, consisting of an immediate and controlled release layer, was prepared by direct compression technique. The controlled release effect was achieved by using various hydrophilic natural, semi synthetic and synthetic controlled release polymers such as xanthan gum, hydroxypropyl methylcellulose (HPMC and polyethylene oxide (PEO to modulate the release of the drug. The in vitro drug release profiles showed the biphasic release behavior in which the immediate release (IR layer containing the lornoxicam was released within 15 minutes, whereas the controlled release (CR layer controlled the drug release for up to 24 h. All the bilayered tablets formulated have followed the zero order release with non-Fickian diffusion controlled release mechanism after the initial burst release. FTIR studies revealed that there was no interaction between the drug and polymers used in the study. Statistical analysis (ANOVA showed no significant difference in the cumulative amount of drug release after 15 min, but significant difference (p O objetivo do presente trabalho foi desenvolver comprimidos bicamada de lornoxicam para atingir padrão de liberação bifásica. Preparou-se, por compressão direta, comprimido bicamada, consistindo de uma camada de liberação imediata e uma de liberação controlada. A liberação controlada foi obtida pelo uso de vários polímeros naturais hidrofílicos, semi-sintéticos e sintéticos, tais como goma xantana, hidroxipropilmetil celulose (HPMC e óxido de polietileno (PEO para modular a liberação do fármaco. Os perfis de liberação in vitro mostraram comportamento bifásico em que a camada de liberação imediata (IR contendo lornoxicam foi liberada em 15 minutos, enquanto a camada de liberação controlada (CR liberou o fármaco em mais de 24 horas, Todos os comprimidos bicamada

  9. Novel Measurements of Aerosol Particle Interfaces Using Biphasic Microfluidics

    Science.gov (United States)

    Metcalf, A. R.; Dutcher, C. S.

    2014-12-01

    Secondary organic aerosol (SOA) particles are nearly ubiquitous in the atmosphere and yet there remains large uncertainties in their formation processes and ambient properties. These particles are complex microenvironments, which can contain multiple interfaces due to internal aqueous-organic phase partitioning and to the external liquid-vapor surface. These aerosol interfaces can profoundly affect the fate of condensable organic compounds emitted into the atmosphere by altering the way in which organic vapors interact with the ambient aerosol. Aerosol interfaces affect particle internal structure, species uptake, equilibrium partitioning, activation to cloud condensation or ice nuclei, and optical properties. For example, organic thin films can shield the core of the aerosol from the ambient environment, which may disrupt equilibrium partitioning and mass transfer. To improve our ability to accurately predict the fate of SOA in the atmosphere, we must improve our knowledge of aerosol interfaces and their interactions with the ambient environment. Few technologies exist to accurately probe aerosol interfaces at atmospherically-relevant conditions. In this talk, a novel method using biphasic microscale flows will be introduced for generating, trapping, and perturbing complex interfaces at atmospherically relevant conditions. These microfluidic experiments utilize high-speed imaging to monitor interfacial phenomena at the microscale and are performed with phase contrast and fluorescence microscopy on a temperature-controlled inverted microscope stage. From these experiments, interfacial thermodynamic properties such as surface tension, rheological properties such as interfacial moduli, and kinetic properties such as mass transfer coefficients can be measured or inferred. Chemical compositions of the liquid phases studied here span a range of viscosities and include electrolyte and water soluble organic acid species often observed in the atmosphere, such as mixtures

  10. Core-shell nanoreactors for efficient aqueous biphasic catalysis.

    Science.gov (United States)

    Zhang, Xuewei; Cardozo, Andrés F; Chen, Si; Zhang, Wenjing; Julcour, Carine; Lansalot, Muriel; Blanco, Jean-François; Gayet, Florence; Delmas, Henri; Charleux, Bernadette; Manoury, Eric; D'Agosto, Franck; Poli, Rinaldo

    2014-11-17

    Water-borne phosphine-functionalized core-cross-linked micelles (CCM) consisting of a hydrophobic core and a hydrophilic shell were obtained as stable latexes by reversible addition-fragmentation chain transfer (RAFT) in water in a one-pot, three-step process. Initial homogeneous aqueous-phase copolymerization of methacrylic acid (MAA) and poly(ethylene oxide) methyl ether methacrylate (PEOMA) is followed by copolymerization of styrene (S) and 4-diphenylphosphinostyrene (DPPS), yielding P(MAA-co-PEOMA)-b-P(S-co-DPPS) amphiphilic block copolymer micelles (M) by polymerization-induced self-assembly (PISA), and final micellar cross-linking with a mixture of S and diethylene glycol dimethacrylate. The CCM were characterized by dynamic light scattering and NMR spectroscopy to evaluate size, dispersity, stability, and the swelling ability of various organic substrates. Coordination of [Rh(acac)(CO)2 ] (acac=acetylacetonate) to the core-confined phosphine groups was rapid and quantitative. The CCM and M latexes were then used, in combination with [Rh(acac)(CO)2 ], to catalyze the aqueous biphasic hydroformylation of 1-octene, in which they showed high activity, recyclability, protection of the activated Rh center by the polymer scaffold, and low Rh leaching. The CCM latex gave slightly lower catalytic activity but significantly less Rh leaching than the M latex. A control experiment conducted in the presence of the sulfoxantphos ligand pointed to the action of the CCM as catalytic nanoreactors with substrate and product transport into and out of the polymer core, rather than as a surfactant in interfacial catalysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Biphasic Rapamycin Effects in Lymphoma and Carcinoma Treatment.

    Science.gov (United States)

    Liu, Yang; Pandeswara, Srilakshmi; Dao, Vinh; Padrón, Álvaro; Drerup, Justin M; Lao, Shunhua; Liu, Aijie; Hurez, Vincent; Curiel, Tyler J

    2017-01-15

    mTOR drives tumor growth but also supports T-cell function, rendering the applications of mTOR inhibitors complex especially in T-cell malignancies. Here, we studied the effects of the mTOR inhibitor rapamycin in mouse EL4 T-cell lymphoma. Typical pharmacologic rapamycin (1-8 mg/kg) significantly reduced tumor burden via direct suppression of tumor cell proliferation and improved survival in EL4 challenge independent of antitumor immunity. Denileukin diftitox (DD)-mediated depletion of regulatory T cells significantly slowed EL4 growth in vivo in a T-cell-dependent fashion. However, typical rapamycin inhibited T-cell activation and tumor infiltration in vivo and failed to boost DD treatment effects. Low-dose (LD) rapamycin (75 μg/kg) increased potentially beneficial CD44hiCD62L + CD8 + central memory T cells in EL4 challenge, but without clinical benefit. LD rapamycin significantly enhanced DD treatment efficacy, but DD plus LD rapamycin treatment effects were independent of antitumor immunity. Instead, rapamycin upregulated EL4 IL2 receptor in vitro and in vivo, facilitating direct DD tumor cell killing. LD rapamycin augmented DD efficacy against B16 melanoma and a human B-cell lymphoma, but not against human Jurkat T-cell lymphoma or ID8agg ovarian cancer cells. Treatment effects correlated with IL2R expression, but mechanisms in some tumors were not fully defined. Overall, our data define a distinct, biphasic mechanisms of action of mTOR inhibition at doses that are clinically exploitable, including in T-cell lymphomas. Cancer Res; 77(2); 520-31. ©2016 AACR. ©2016 American Association for Cancer Research.

  12. Ascending-ramp biphasic waveform has a lower defibrillation threshold and releases less troponin I than a truncated exponential biphasic waveform.

    Science.gov (United States)

    Huang, Jian; Walcott, Gregory P; Ruse, Richard B; Bohanan, Scott J; Killingsworth, Cheryl R; Ideker, Raymond E

    2012-09-11

    We tested the hypothesis that the shape of the shock waveform affects not only the defibrillation threshold but also the amount of cardiac damage. Defibrillation thresholds were determined for 11 waveforms-3 ascending-ramp waveforms, 3 descending-ramp waveforms, 3 rectilinear first-phase biphasic waveforms, a Gurvich waveform, and a truncated exponential biphasic waveform-in 6 pigs with electrodes in the right ventricular apex and superior vena cava. The ascending, descending, and rectilinear waveforms had 4-, 8-, and 16-millisecond first phases and a 3.5-millisecond rectilinear second phase that was half the voltage of the first phase. The exponential biphasic waveform had a 60% first-phase and a 50% second-phase tilt. In a second study, we attempted to defibrillate after 10 seconds of ventricular fibrillation with a single ≈30-J shock (6 pigs successfully defibrillated with 8-millisecond ascending, 8-millisecond rectilinear, and truncated exponential biphasic waveforms). Troponin I blood levels were determined before and 2 to 10 hours after the shock. The lowest-energy defibrillation threshold was for the 8-milliseconds ascending ramp (14.6±7.3 J [mean±SD]), which was significantly less than for the truncated exponential (19.6±6.3 J). Six hours after shock, troponin I was significantly less for the ascending-ramp waveform (0.80±0.54 ng/mL) than for the truncated exponential (1.92±0.47 ng/mL) or the rectilinear waveform (1.17±0.45 ng/mL). The ascending ramp has a significantly lower defibrillation threshold and at ≈30 J causes 58% less troponin I release than the truncated exponential biphasic shock. Therefore, the shock waveform affects both the defibrillation threshold and the amount of cardiac damage.

  13. Investigation of structural resorption behavior of biphasic bioceramics with help of gravimetry, μCT, SEM, and XRD.

    Science.gov (United States)

    de Wild, Michael; Amacher, Fabienne; Bradbury, Christopher R; Molenberg, Aart

    2016-04-01

    Resorbable bone substitute materials are widely used for bone augmentation after tumor resection, parallel to implant placement, or in critical size bone defects. In this study, the structural dissolution of a biphasic calcium phosphate bone substitute material with a hydroxyapatite (HA)/tricalcium phosphate (β-TCP) ratio of 60/40 was investigated by repeatedly placing porous blocks in EDTA solution at 37 °C. At several time points, the blocks were investigated by SEM, µCT, and gravimetry. It was found that always complete 2-3 µm sized grains were removed from the structure and that the β-TCP is dissolved more rapidly. This selective dissolution of the β-TCP grains was confirmed by XRD measurements. The blocks were eroded from the outside toward the center. The structure remained mechanically stable because the central part showed a delayed degradation and because the slower dissolving HA grains preserved the integrity of the structure. © 2015 Wiley Periodicals, Inc.

  14. The biphasic effect of extracellular glucose concentration on carbachol-induced fluid secretion from mouse submandibular glands.

    Science.gov (United States)

    Terachi, Momomi; Hirono, Chikara; Kitagawa, Michinori; Sugita, Makoto

    2018-06-01

    Cholinergic agonists evoke elevations of the cytoplasmic free-calcium concentration ([Ca 2+ ] i ) to stimulate fluid secretion in salivary glands. Salivary flow rates are significantly reduced in diabetic patients. However, it remains elusive how salivary secretion is impaired in diabetes. Here, we used an ex vivo submandibular gland perfusion technique to characterize the dependency of salivary flow rates on extracellular glucose concentration and activities of glucose transporters expressed in the glands. The cholinergic agonist carbachol (CCh) induced sustained fluid secretion, the rates of which were modulated by the extracellular glucose concentration in a biphasic manner. Both lowering the extracellular glucose concentration to less than 2.5 mM and elevating it to higher than 5 mM resulted in decreased CCh-induced fluid secretion. The CCh-induced salivary flow was suppressed by phlorizin, an inhibitor of the sodium-glucose cotransporter 1 (SGLT1) located basolaterally in submandibular acinar cells, which is altered at the protein expression level in diabetic animal models. Our data suggest that SGLT1-mediated glucose uptake in acinar cells is required to maintain the fluid secretion by sustaining Cl - secretion in real-time. High extracellular glucose levels may suppress the CCh-induced secretion of salivary fluid by altering the activities of ion channels and transporters downstream of [Ca 2+ ] i signals. © 2018 Eur J Oral Sci.

  15. B-Raf and CRHR1 internalization mediate biphasic ERK1/2 activation by CRH in hippocampal HT22 Cells.

    Science.gov (United States)

    Bonfiglio, Juan J; Inda, Carolina; Senin, Sergio; Maccarrone, Giuseppina; Refojo, Damián; Giacomini, Damiana; Turck, Christoph W; Holsboer, Florian; Arzt, Eduardo; Silberstein, Susana

    2013-03-01

    CRH is a key regulator of neuroendocrine, autonomic, and behavioral response to stress. CRH-stimulated CRH receptor 1 (CRHR1) activates ERK1/2 depending on intracellular context. In a previous work, we demonstrated that CRH activates ERK1/2 in limbic areas of the mouse brain (hippocampus and basolateral amygdala). ERK1/2 is an essential mediator of hippocampal physiological processes including emotional behavior, synaptic plasticity, learning, and memory. To elucidate the molecular mechanisms by which CRH activates ERK1/2 in hippocampal neurons, we used the mouse hippocampal cell line HT22. We document for the first time that ERK1/2 activation in response to CRH is biphasic, involving a first cAMP- and B-Raf-dependent early phase and a second phase that critically depends on CRHR1 internalization and β-arrestin2. By means of mass-spectrometry-based screening, we identified B-Raf-associated proteins that coimmunoprecipitate with endogenous B-Raf after CRHR1 activation. Using molecular and pharmacological tools, the functional impact of selected B-Raf partners in CRH-dependent ERK1/2 activation was dissected. These results indicate that 14-3-3 proteins, protein kinase A, and Rap1, are essential for early CRH-induced ERK1/2 activation, whereas dynamin and vimentin are required for the CRHR1 internalization-dependent phase. Both phases of ERK1/2 activation depend on calcium influx and are affected by calcium/calmodulin-dependent protein kinase II inactivation. Thus, this report describes the dynamics and biphasic nature of ERK1/2 activation downstream neuronal CRHR1 and identifies several new critical components of the CRHR1 signaling machinery that selectively controls the early and late phases of ERK1/2 activation, thus providing new potential therapeutic targets for stress-related disorders.

  16. Evaluation of the finite element software ABAQUS for biomechanical modelling of biphasic tissues.

    Science.gov (United States)

    Wu, J Z; Herzog, W; Epstein, M

    1998-02-01

    The biphasic cartilage model proposed by Mow et al. (1980) has proven successful to capture the essential mechanical features of articular cartilage. In order to analyse the joint contact mechanics in real, anatomical joints, the cartilage model needs to be implemented into a suitable finite element code to approximate the irregular surface geometries of such joints. However, systematic and extensive evaluation of the capacity of commercial software for modelling the contact mechanics with biphasic cartilage layers has not been made. This research was aimed at evaluating the commercial finite element software ABAQUS for analysing biphasic soft tissues. The solutions obtained using ABAQUS were compared with those obtained using other finite element models and analytical solutions for three numerical tests: an unconfined indentation test, a test with the contact of a spherical cartilage surface with a rigid plate, and an axi-symmetric joint contact test. It was concluded that the biphasic cartilage model can be implemented into the commercial finite element software ABAQUS to analyse practical joint contact problems with biphasic articular cartilage layers.

  17. Equivalence between short-time biphasic and incompressible elastic material responses.

    Science.gov (United States)

    Ateshian, Gerard A; Ellis, Benjamin J; Weiss, Jeffrey A

    2007-06-01

    Porous-permeable tissues have often been modeled using porous media theories such as the biphasic theory. This study examines the equivalence of the short-time biphasic and incompressible elastic responses for arbitrary deformations and constitutive relations from first principles. This equivalence is illustrated in problems of unconfined compression of a disk, and of articular contact under finite deformation, using two different constitutive relations for the solid matrix of cartilage, one of which accounts for the large disparity observed between the tensile and compressive moduli in this tissue. Demonstrating this equivalence under general conditions provides a rationale for using available finite element codes for incompressible elastic materials as a practical substitute for biphasic analyses, so long as only the short-time biphasic response is sought. In practice, an incompressible elastic analysis is representative of a biphasic analysis over the short-term response deltatelasticity tensor, and K is the hydraulic permeability tensor of the solid matrix. Certain notes of caution are provided with regard to implementation issues, particularly when finite element formulations of incompressible elasticity employ an uncoupled strain energy function consisting of additive deviatoric and volumetric components.

  18. Dissolved nutrients and atrazine removal by column-scale monophasic and biphasic rain garden model systems.

    Science.gov (United States)

    Yang, Hanbae; McCoy, Edward L; Grewal, Parwinder S; Dick, Warren A

    2010-08-01

    Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. We compared hydraulic performance and removal efficiencies of nutrients and atrazine in a monophasic rain garden design versus a biphasic design at a column-scale using simulated runoff. The biphasic rain garden was designed to increase retention time and removal efficiency of runoff pollutants by creating a sequence of water saturated to unsaturated conditions. We also evaluated the effect of C substrate availability on pollutant removal efficiency in the biphasic rain garden. Five simulated runoff events with various concentrations of runoff pollutants (i.e. nitrate, phosphate, and atrazine) were applied to the monophasic and biphasic rain gardens once every 5d. Hydraulic performance was consistent over the five simulated runoff events. Peak flow was reduced by approximately 56% for the monophasic design and 80% for the biphasic design. Both rain garden systems showed excellent removal efficiency of phosphate (89-100%) and atrazine (84-100%). However, significantly (prain garden (29-39%). Addition of C substrate in the form of glucose increased removal efficiency of nitrate significantly (prain gardens. (c) 2010 Elsevier Ltd. All rights reserved.

  19. Aminoglycoside antibiotics as a tool for the study of the biological role of calcium ions. Historical overview.

    Science.gov (United States)

    Corrado, A P; de Morais, I P; Prado, W A

    1989-01-01

    Beginning with the pioneering work of Vital-Brazil and Corrado (1957), which suggested a possible interaction between aminoglycoside antibiotics (AGA) and calcium ions at the neuromuscular junction, the authors review the studies that demonstrated the existence of a competitive antagonism between AGA and calcium ions. In view of the low liposolubility of AGA and their inability to cross biological membranes, this antagonism seems to occur exclusively at calcium-binding sites at the level of the outer opening of calcium channels of the N-subtype, which are also the sites of interaction of omega-conotoxin. Being highly water soluble, AGA are easily removed from their binding sites with a consequent rapid reversal of their effects, a factor of primary importance to explain their wide use as tools in the pharmacological analysis of the study of the biological role of calcium ion on the membrane's outer surface. This use has advantages over the use of inorganic di- and trivalent cations such as Mg2+, Mn2+, Cd2+, Ni2+, La3+, etc., since the latter, though they are considered to be the most specific competitive antagonists of calcium ions, may induce biphasic effects due to their ability to cross the membranes and replace calcium and/or increase intracellular calcium concentration. The performance of AGA is also superior when compared with the so-called "specific" organic calcium antagonists--verapamil and nifedipine derivatives--since the latter, in addition to inducing possible biphasic effects, antagonize calcium in a non-competitive manner. Finally, the authors remark that AGA-Ca2+ antagonism relevance is not limited only to basic aspects and that it may have therapeutic implications since it provides alternatives for reducing the toxic adverse effects of this important group of antibiotics.

  20. Calcium and magnesium determination

    International Nuclear Information System (INIS)

    Bhattacharya, S.K.

    1982-01-01

    The roles of calcium and magnesium in human health and disease have been extensively studied. Calcium and magnesium have been determined in biological specimens by atomic absorption spectroscopy using stiochiometric nitrous oxide-acetylene flame

  1. Fenoprofen calcium overdose

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  2. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium-channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium-channel blockers are a type of medicine used ...

  3. Biomimetic fabrication of a three-level hierarchical calcium phosphate/collagen/hydroxyapatite scaffold for bone tissue engineering

    International Nuclear Information System (INIS)

    Zhou, Changchun; Ye, Xingjiang; Fan, Yujiang; Tan, Yanfei; Qing, Fangzu; Zhang, Xingdong; Ma, Liang

    2014-01-01

    A three-level hierarchical calcium phosphate/collagen/hydroxyapatite (CaP/Col/HAp) scaffold for bone tissue engineering was developed using biomimetic synthesis. Porous CaP ceramics were first prepared as substrate materials to mimic the porous bone structure. A second-level Col network was then composited into porous CaP ceramics by vacuum infusion. Finally, a third-level HAp layer was achieved by biomimetic mineralization. The three-level hierarchical biomimetic scaffold was characterized using scanning electron microscopy, energy-dispersive x-ray spectra, x-ray diffraction and Fourier transform infrared spectroscopy, and the mechanical properties of the scaffold were evaluated using dynamic mechanical analysis. The results show that this scaffold exhibits a similar structure and composition to natural bone tissues. Furthermore, this three-level hierarchical biomimetic scaffold showed enhanced mechanical strength compared with pure porous CaP scaffolds. The biocompatibility and osteoinductivity of the biomimetic scaffolds were evaluated using in vitro and in vivo tests. Cell culture results indicated the good biocompatibility of this biomimetic scaffold. Faster and increased bone formation was observed in these scaffolds following a six-month implantation in the dorsal muscles of rabbits, indicating that this biomimetic scaffold exhibits better osteoinductivity than common CaP scaffolds. (papers)

  4. Fabrication of human hair keratin/jellyfish collagen/eggshell-derived hydroxyapatite osteoinductive biocomposite scaffolds for bone tissue engineering: From waste to regenerative medicine products.

    Science.gov (United States)

    Arslan, Yavuz Emre; Sezgin Arslan, Tugba; Derkus, Burak; Emregul, Emel; Emregul, Kaan C

    2017-06-01

    In the present study, we aimed at fabricating an osteoinductive biocomposite scaffold using keratin obtained from human hair, jellyfish collagen and eggshell-derived nano-sized spherical hydroxyapatite (nHA) for bone tissue engineering applications. Keratin, collagen and nHA were characterized with the modified Lowry method, free-sulfhydryl groups and hydroxyproline content analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and thermal gravimetric analysis (TGA) which confirmed the success of the extraction and/or isolation processes. Human adipose mesenchymal stem cells (hAMSCs) were isolated and the cell surface markers were characterized via flow cytometry analysis in addition to multilineage differentiation capacity. The undifferentiated hAMSCs were highly positive for CD29, CD44, CD73, CD90 and CD105, but were not seen to express hematopoietic cell surface markers such as CD14, CD34 and CD45. The cells were successfully directed towards osteogenic, chondrogenic and adipogenic lineages in vitro. The microarchitecture of the scaffolds and cell attachment were evaluated using scanning electron microscopy (SEM). The cell viability on the scaffolds was assessed by the MTT assay which revealed no evidence of cytotoxicity. The osteogenic differentiation of hAMSCs on the scaffolds was determined histologically using alizarin red S, osteopontin and osteonectin stainings. Early osteogenic differentiation markers of hAMSCs were significantly expressed on the collagen-keratin-nHA scaffolds. In conclusion, it is believed that collagen-keratin-nHA osteoinductive biocomposite scaffolds have the potential of being used in bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  6. Pretreatment of Eucalyptus in biphasic system for furfural production and accelerated enzymatic hydrolysis.

    Science.gov (United States)

    Zhang, Xiudong; Bai, Yuanyuan; Cao, Xuefei; Sun, Runcang

    2017-08-01

    Herein, an efficient biphasic pretreatment process was developed to improve the production of furfural (FF) and glucose from Eucalyptus. The influence of formic acid and NaCl on FF production from xylose in water and various biphasic systems was investigated. Results showed that the addition of formic acid and NaCl significantly promoted the FF yield, and the biphasic system of MIBK (methyl isobutyl ketone)/water exhibited the best performance for FF production. Then the Eucalyptus was pretreated in the MIBK/water system, and a maximum FF yield of 82.0% was achieved at 180°C for 60min. Surface of the pretreated Eucalyptus became relatively rough and loose, and its crystallinity index increased obviously due to the removal of hemicelluloses and lignin. The pretreated Eucalyptus samples showed much higher enzymatic hydrolysis rates (26.2-70.7%) than the raw Eucalyptus (14.5%). Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.

    1985-01-01

    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of

  8. Optimization of calcium phosphate fine ceramic powders preparation

    Science.gov (United States)

    Sezanova, K.; Tepavitcharova, S.; Rabadjieva, D.; Gergulova, R.; Ilieva, R.

    2013-12-01

    The effect of biomimetic synthesis method, reaction medium and further precursor treatments on the chemical and phase composition, crystal size and morphology of calcium phosphates was examined. Nanosized calcium phosphate precursors were biomimetically precipitated by the method of continuous precipitation in three types of reaction media at pH 8: (i) SBF as an inorganic electrolyte system; (ii) organic (glycerine) modified SBF (volume ratio of 1:1); (iii) polymer (10 g/l xanthan gum or 10 g/l guar gum) modified SBF (volume ratio of 1:1). After maturation (24 h) the samples were lyophilized, calcinated at 300°C for 3 hours, and washed with water, followed by new gelation, lyophilization and step-wise (200, 400, 600, 800, and 1000°C, each for 3 hours) sintering. The reaction medium influenced the chemical composition and particle size but not the morphology of the calcium phosphate powders. In all studied cases bi-phase calcium phosphate fine powders with well-shaped spherical grains, consisting of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) with a Ca/P ratio of 1.3 - 1.6 were obtained. The SBF modifiers decreased the particle size of the product in the sequence guar gum ˜ xanthan gum < glycerin < SBF medium.

  9. The standard biphasic-contrast examination of the stomach and duodenum

    International Nuclear Information System (INIS)

    Op den Orth, J.O.

    1979-01-01

    A standard examination has been developed, called biphasic, because it combines the advantages of positive-contrast and double-contrast techniques. The theoretical background and technique of this examination are described and the basic interpretation of double-contrast studies stated. General remarks on the results and on the complementary role of radiological examination and endoscopy are included. A quantitative study of standard biphasic-contrast examinations in patients over a period of 3 years is presented. Finally a radiological atlas of common lesions of the stomach and duodenum is given. (C.F.)

  10. Cytosolic calcium rises and related events in ergosterol-treated Nicotiana cells.

    Science.gov (United States)

    Vatsa, Parul; Chiltz, Annick; Luini, Estelle; Vandelle, Elodie; Pugin, Alain; Roblin, Gabriel

    2011-07-01

    The typical fungal membrane component ergosterol was previously shown to trigger defence responses and protect plants against pathogens. Most of the elicitors mobilize the second messenger calcium, to trigger plant defences. We checked the involvement of calcium in response to ergosterol using Nicotiana plumbaginifolia and Nicotiana tabacum cv Xanthi cells expressing apoaequorin in the cytosol. First, it was verified if ergosterol was efficient in these cells inducing modifications of proton fluxes and increased expression of defence-related genes. Then, it was shown that ergosterol induced a rapid and transient biphasic increase of free [Ca²⁺](cyt) which intensity depends on ergosterol concentration in the range 0.002-10 μM. Among sterols, this calcium mobilization was specific for ergosterol and, ergosterol-induced pH and [Ca²⁺](cyt) changes were specifically desensitized after two subsequent applications of ergosterol. Specific modulators allowed elucidating some events in the signalling pathway triggered by ergosterol. The action of BAPTA, LaCl₃, nifedipine, verapamil, neomycin, U73122 and ruthenium red suggested that the first phase was linked to calcium influx from external medium which subsequently triggered the second phase linked to calcium release from internal stores. The calcium influx and the [Ca²⁺](cyt) increase depended on upstream protein phosphorylation. The extracellular alkalinization and ROS production depended on calcium influx but, the ergosterol-induced MAPK activation was calcium-independent. ROS were not involved in cytosolic calcium rise as described in other models, indicating that ROS do not systematically participate in the amplification of calcium signalling. Interestingly, ergosterol-induced ROS production is not linked to cell death and ergosterol does not induce any calcium elevation in the nucleus. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  11. Calcium phosphate formation from sea urchin - (brissus latecarinatus via modified mechano-chemical (ultrasonic conversion method

    Directory of Open Access Journals (Sweden)

    R. Samur

    2013-07-01

    Full Text Available This study aims to produce apatite structures, such as hydroxyapatite (HA and fluorapatite (FA, from precursor calcium phosphates of biological origin, namely from sea urchin, with mechano-chemical stirring and hot-plating conversion method. The produced materials were heat treated at 800 °C for 4 hours. X-ray diffraction and scanning electron microscopy (SEM studies were conducted. Calcium phosphate phases were developed. The SEM images showed the formation of micro to nano-powders. The experimental results suggest that sea urchin, Brissus latecarinatus skeleton could be an alternative source for the production of various mono or biphasic calcium phosphates with simple and economic mechano-chemical (ultrasonic conversion method.

  12. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Recker, R.R.

    1985-01-01

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  13. Effect of nasal continuous and biphasic positive airway pressure on lung volume in preterm infants

    NARCIS (Netherlands)

    Miedema, Martijn; van der Burg, Pauline S.; Beuger, Sabine; de Jongh, Frans H.; Frerichs, Inez; van Kaam, Anton H.

    2013-01-01

    To monitor regional changes in end-expiratory lung volume (EELV), tidal volumes, and their ventilation distribution during different levels of nasal continuous positive airway pressure (nCPAP) and nasal biphasic positive airway pressure (BiPAP) in stable preterm infants. By using electrical

  14. A randomized trial comparing monophasic and biphasic waveform shocks for external cardioversion of atrial fibrillation

    NARCIS (Netherlands)

    Koster, Rudolph W.; Dorian, Paul; Chapman, Fred W.; Schmitt, Paul W.; O'Grady, Sharon G.; Walker, Robert G.

    2004-01-01

    Background We compared efficacy of and pain felt after biphasic truncated exponential (BTE) and monophasic damped sine (MDS) shocks in patients undergoing external cardioversion of atrial fibrillation (AF). Methods Patients with AF were randomized to BTE or MDS waveform cardioversion. Successive

  15. Occurrence of amylose-lipid complexes in teff and maize starch biphasic pastes

    CSIR Research Space (South Africa)

    Wokadala, OC

    2012-09-01

    Full Text Available The occurrence of amylose–lipid complexes was determined in maize and teff starch biphasic pastes i.e. peak viscosity pastes at short and prolonged pasting times. Maize and teff starches were pasted for 11.5 and 130 min with or without added stearic...

  16. A re-examination of the biphasic theory of skeletal muscle growth.

    Science.gov (United States)

    Levine, A S; Hegarty, P V

    1977-01-01

    Because of the importance of fibre diameter measurements it was decided to re-evaluate the biphasic theory of skeletal muscle growth and development. This theory proposes an initial memophasic distribution of muscle fibres which changes to a biphasic distribution during development. The theory is based on observations made on certain muscles in mice, where two distinct populations of fibre diameters (20 and 40 micronm) contribute to the biphasic distribution. In the present investigation corss sections of frozen biceps brachii of mice in rigor mortis were examined. The rigor state was used to avoid complications produced by thaw-rigor contraction. The diameters of the outermost and innermost fibres were found to be significantly different. However, if the outer and inner fibres were combined to form one group, no significant difference between this group and other random groups was found. The distributions of all groups were monophasic. The diameters of isolated fibres from mice and rats also displayed a monophasic distribution. This evidence leads to the conclusion that the biphasic theory of muscle growth is untenable. Some of the variables which may occur in fibre size and shape are discussed. Images Fig. 1 PMID:858691

  17. Biphasic single-reactor process for dehydration of xylose and hydrogenation of produced furfural

    NARCIS (Netherlands)

    Ordomskiy, V.; Schouten, J.C.; Schaaf, van der J.; Nijhuis, T.A.

    2013-01-01

    The processes of xylose dehydration and the consecutive furfural hydrogenation have been combined in a single biphasic reactor. The dehydration was studied over Amberlyst-15 and the hydrogenation over a hydrophobic Ru/C catalyst. 1-Butanol, 2-methyltetrahydrofuran and cyclohexane were used as

  18. Temperature dependence of microwave absorption phenomena in single and biphase soft magnetic microwires

    Czech Academy of Sciences Publication Activity Database

    El Kammouni, R.; Vázquez, M.; Lezama, L.; Kurlyandskaya, G.; Kraus, Luděk

    2014-01-01

    Roč. 368, Nov (2014), 126-132 ISSN 0304-8853 Institutional support: RVO:68378271 Keywords : magnetic microwire * ferromagnetic resonance * microwave absorption * biphase magnetic system Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.970, year: 2014

  19. Hydroxyapatite/polylactide biphasic combination scaffold loaded with dexamethasone for bone regeneration.

    Science.gov (United States)

    Son, Jun-Sik; Kim, Su-Gwan; Oh, Ji-Su; Appleford, Mark; Oh, Sunho; Ong, Joo L; Lee, Kyu-Bok

    2011-12-15

    This study presents a novel design of a ceramic/polymer biphasic combination scaffold that mimics natural bone structures and is used as a bone graft substitute. To mimic the natural bone structures, the outside cortical-like shells were composed of porous hydroxyapatite (HA) with a hollow interior using a polymeric template-coating technique; the inner trabecular-like core consisted of porous poly(D,L-lactic acid) (PLA) that was loaded with dexamethasone (DEX) and was directly produced using a particle leaching/gas forming technique to create the inner diameter of the HA scaffold. It was observed that the HA and PLA parts of the fabricated HA/PLA biphasic scaffold contained open and interconnected pore structures, and the boundary between both parts was tightly connected without any gaps. It was found that the structure of the combination scaffold was analogous to that of natural bone based on micro-computed tomography analysis. Additionally, the dense, uniform apatite layer was formed on the surface of the HA/PLA biphasic scaffold through a biomimetic process, and DEX was successfully released from the PLA of the biphasic scaffold over a 1-month period. This release caused human embryonic palatal mesenchyme cells to proliferate, differentiate, produce ECM, and form tissue in vitro. Therefore, it was concluded that this functionally graded scaffold is similar to natural bone and represents a potential bone-substitute material. Copyright © 2011 Wiley Periodicals, Inc.

  20. Alpha alumina synthesis by laser treatment of bi-phasic nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Aktas, Cenk, E-mail: cenk.aktas@inm-gmbh.de [Leibniz Institute for New Materials, D2 2 Campus, 66123 Saarbrücken (Germany); Lee, Juseok; Míro, Marina Martinez [Leibniz Institute for New Materials, D2 2 Campus, 66123 Saarbrücken (Germany); Barnoush, Afrooz [Norwegian University of Science and Technology, Trondheim (Norway); Saarland University, D2 2 Campus, 66123 Saarbrücken (Germany); Veith, Michael [Leibniz Institute for New Materials, D2 2 Campus, 66123 Saarbrücken (Germany)

    2013-08-01

    Al/Al{sub 2}O{sub 3} bi-phasic nanowires (Al-core/Al{sub 2}O{sub 3} shell) are prepared by chemical vapor deposition (CVD) using single source precursor (SSP) approach. Such bi-phasic nanostructures were heat-treated using an argon laser operating at visible wavelengths. Al core seems to act as an active binder, which might decrease the inhomogeneous heating and thermal gradients. Nanoindentation method is used to estimate the hardness of the laser treated surfaces. Hardness values and pop-in behaviour in loading-curve indicate a formation of α-Al{sub 2}O{sub 3} with very low defect density. It is believed that Al/Al{sub 2}O{sub 3} bi-phasic layers exhibit a dynamic change by transforming into alumina after the laser irradiation and this leads to alteration of the optical absorption especially in the visible wavelength region. Following the full transformation to alumina, the surface reflects back the laser light which hinders inhomogeneous and excessive heating. In this context, laser treatment of Al/Al{sub 2}O{sub 3} bi-phasic nanowires provides a controlled sintering process which can open up various applications in different fields.

  1. The effect of microwave and conventional heating on a modified sol-gel derived biphasic calcium phosphate

    Science.gov (United States)

    Herradi, S.; Bouhazma, S.; Khaldi, M.; El Hachadi, A.; El Bali, B.; Lachkar, M.

    2018-03-01

    A facile sol-gel method was used to synthesize either hydroxyapatite (HA) or beta-tricalcium phosphate (β-TCP) as the major phase. Herein, we report, on the one hand, the effect of a very low maturation temperature on the final powder composition after drying step, and on the other hand, we compare the effect of calcination of this powder by microwave or electric furnace. It was found that microwave heating has led to the formation of hydroxyapatite phase upon 180°C for 20 minutes, however, XRD patterns show that the powder becomes less crystallized upon 220°C and amorphous upon 230°C. In contrast, furnace heating at 600°C and 700°C converts the as-synthesized powder to β-TCP as the major phase together with HA as the minor phase. This work shows the possibility to obtain the as-prepared BCP at much lower maturation temperature; it also gives an insight into the role, of either microwave or conventional heating, in controlling the ratio between HA and β-TCP in the sintered powder.

  2. Histological Evaluation of Degradable Guided Bone Regeneration Membranes Prepared from Poly(trimethylene carbonate) and Biphasic Calcium Phosphate Composites

    NARCIS (Netherlands)

    Zeng, Ni; van Leeuwen, Anne; Bos, Ruud R.M.; Grijpma, Dirk W.; Kuijer, Roel

    2013-01-01

    In oral and maxillofacial surgery, guided bone regeneration using barrier membranes is an important strategy to treat bone defects. The currently used barrier membranes have important disadvantages. Barrier membranes prepared from resorbable poly(trimethylene carbonate) (PTMC) performed as well as

  3. Histological evaluation of degradable guided bone regeneration membranes prepared from poly(trimethylene carbonate) and biphasic calcium phosphate composites

    NARCIS (Netherlands)

    Zeng, Ni; van Leeuwen, Anne; Bos, Ruud R.M.; Grijpma, Dirk W.; Kuijer, Roel

    2013-01-01

    In oral and maxillofacial surgery, guided bone regeneration using barrier membranes is an important strategy to treat bone defects. The currently used barrier membranes have important disadvantages. Barrier membranes prepared from resorbable poly(trimethylene carbonate) (PTMC) performed as well as

  4. Calcium channel blocker poisoning

    Directory of Open Access Journals (Sweden)

    Miran Brvar

    2005-04-01

    Full Text Available Background: Calcium channel blockers act at L-type calcium channels in cardiac and vascular smooth muscles by preventing calcium influx into cells with resultant decrease in vascular tone and cardiac inotropy, chronotropy and dromotropy. Poisoning with calcium channel blockers results in reduced cardiac output, bradycardia, atrioventricular block, hypotension and shock. The findings of hypotension and bradycardia should suggest poisoning with calcium channel blockers.Conclusions: Treatment includes immediate gastric lavage and whole-bowel irrigation in case of ingestion of sustainedrelease products. All patients should receive an activated charcoal orally. Specific treatment includes calcium, glucagone and insulin, which proved especially useful in shocked patients. Supportive care including the use of catecholamines is not always effective. In the setting of failure of pharmacological therapy transvenous pacing, balloon pump and cardiopulmonary by-pass may be necessary.

  5. Dengue and Calcium

    OpenAIRE

    Shivanthan, Mitrakrishnan C; Rajapakse, Senaka

    2014-01-01

    Dengue is potentially fatal unless managed appropriately. No specific treatment is available and the mainstay of treatment is fluid management with careful monitoring, organ support, and correction of metabolic derangement. Evidence with regards to the role of calcium homeostasis in dengue is limited. Low blood calcium levels have been demonstrated in dengue infection and hypocalcemia maybe more pronounced in more severe forms. The cause of hypocalcemia is likely to be multifactorial. Calcium...

  6. Calcium Channel Blockers

    Science.gov (United States)

    ... Certain calcium channel blockers interact with grapefruit products. Kaplan NM, et al. Treatment of hypertension: Drug therapy. In: Kaplan's Clinical Hypertension. 11th ed. Philadelphia, Pa.: Wolters Kluwer ...

  7. Osteoinduction and proliferation of bone-marrow stromal cells in three-dimensional poly (ε-caprolactone)/ hydroxyapatite/collagen scaffolds.

    Science.gov (United States)

    Wang, Ting; Yang, Xiaoyan; Qi, Xin; Jiang, Chaoyin

    2015-05-08

    Osteoinduction and proliferation of bone-marrow stromal cells (BMSCs) in three-dimensional (3D) poly(ε-caprolactone) (PCL) scaffolds have not been studied throughly and are technically challenging. This study aimed to optimize nanocomposites of 3D PCL scaffolds to provide superior adhesion, proliferation and differentiation environment for BMSCs in this scenario. BMSCs were isolated and cultured in a novel 3D tissue culture poly(ε-caprolactone) (PCL) scaffold coated with poly-lysine, hydroxyapatite (HAp), collagen and HAp/collagen. Cell morphology was observed and BMSC biomarkers for osteogenesis, osteoblast differentiation and activation were analyzed. Scanning Electron Microscope (SEM) micrographs showed that coating materials were uniformly deposited on the surface of PCL scaffolds and BMSCs grew and aggregated to form clusters during 3D culture. Both mRNA and protein levels of the key players of osteogenesis and osteoblast differentiation and activation, including runt-related transcription factor 2 (Runx2), alkaline phosphates (ALP), osterix, osteocalcin, and RANKL, were significantly higher in BMSCs seeded in PCL scaffolds coated with HAp or HAp/collagen than those seeded in uncoated PCL scaffolds, whereas the expression levels were not significantly different in collagen or poly-lysine coated PCL scaffolds. In addition, poly-lysine, collagen, HAp/collagen, and HAp coated PCL scaffolds had significantly more viable cells than uncoated PCL scaffolds, especially scaffolds with HAp/collagen and collagen-alone coatings. That BMSCs in HAp or HAp/collagen PCL scaffolds had remarkably higher ALP activities than those in collagen-coated alone or uncoated PCL scaffolds indicating higher osteogenic differentiation levels of BMSCs in HAp or HAp/collagen PCL scaffolds. Moreover, morphological changes of BMSCs after four-week of 3D culture confirmed that BMSCs successfully differentiated into osteoblast with spread-out phenotype in HAp/collagen coated PCL scaffolds

  8. Three-dimensional CaP/gelatin lattice scaffolds with integrated osteoinductive surface topographies for bone tissue engineering

    International Nuclear Information System (INIS)

    Nadeem, Danish; Su, Bo; Smith, Carol-Anne; Dalby, Matthew J; Dominic Meek, R M; Lin, Sien; Li, Gang

    2015-01-01

    Surface topography is known to influence stem cells and has been widely used as physical stimuli to modulate cellular behaviour including adhesion, proliferation and differentiation on 2D surfaces. Integration of well-defined surface topography into three-dimensional (3D) scaffolds for tissue engineering would be useful to direct the cell fate for intended applications. Technical challenges are remaining as how to fabricate such 3D scaffolds with controlled surface topography from a range of biodegradable and biocompatible materials. In this paper, a novel fabrication process using computer numerically controlled machining and lamination is reported to make 3D calcium phosphate/gelatin composite scaffolds with integrated surface micropatterns that are introduced by embossing prior to machining. Geometric analysis shows that this method is versatile and can be used to make a wide range of lattices with porosities that meet the basic requirements for bone tissue engineering. Both in vitro and in vivo studies show that micropatterned composite scaffolds with surfaces comprising 40 μm pits and 50 μm grooves were optimal for improved osteogenesis. The results have demonstrated the potential of a novel fabrication process for producing cell-instructive scaffolds with designed surface topographies to induce specific tissue regeneration. (paper)

  9. ATP stimulates calcium influx in primary astrocyte cultures

    International Nuclear Information System (INIS)

    Neary, J.T.; van Breemen, C.; Forster, E.; Norenberg, L.O.; Norenberg, M.D.

    1988-01-01

    The effect of ATP and other purines on 45 Ca uptake was studied in primary cultures of rat astrocytes. Treatment of the cells with ATP for 1 to 30 min brought about an increase in cellular 45 Ca. Stimulation of calcium influx by ATP was investigated using a 90 sec exposure to 45 Ca and over a concentration range of 0.1 nM to 3 mM; a biphasic dose-response curve was obtained with EC50 values of 0.3 nM and 9 uM, indicating the presence of low and high affinity purinergic binding sites. Similar levels of 45 Ca influx at 90 sec were observed with ATP, ADP and adenosine (all at 100 uM). Prior treatment of the cultures with LaCl3 blocked the purine-induced 45 Ca influx. These findings indicate that one pathway for calcium entry in astrocytes involves purinergic receptor-operated, calcium channels

  10. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

    Alexander, R Todd; Cordat, Emmanuelle; Chambrey, Régine

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and inhibi...

  11. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  12. Regeneration of skull bones in adult rabbits after implantation of commercial osteoinductive materials and transplantation of a tissue-engineering construct.

    Science.gov (United States)

    Volkov, A V; Alekseeva, I S; Kulakov, A A; Gol'dshtein, D V; Shustrov, S A; Shuraev, A I; Arutyunyan, I V; Bukharova, T B; Rzhaninova, A A; Bol'shakova, G B; Grigor'yan, A S

    2010-10-01

    We performed a comparative study of reparative osteogenesis in rabbits with experimental critical defects of the parietal bones after implantation of commercial osteoinductive materials "Biomatrix", "Osteomatrix", "BioOss" in combination with platelet-rich plasma and transplantation of a tissue-engineering construct on the basis of autogenic multipotent stromal cells from the adipose tissue predifferentiated in osteogenic direction. It was found that experimental reparative osteogenesis is insufficiently stimulated by implantation materials and full-thickness trepanation holes were not completely closed. After transplantation of the studied tissue-engineering construct, the defect was filled with full-length bone regenerate (in the center of the regenerate and from the maternal bone) in contrast to control and reference groups, where the bone tissue was formed only on the side of the maternal bone. On day 120 after transplantation of the tissue-engineering construct, the percent of newly-formed bone tissue in the regenerate was 24% (the total percent of bone tissue in the regenerate was 39%), which attested to active incomplete regenerative process in contrast to control and reference groups. Thus, the study demonstrated effective regeneration of the critical defects of the parietal bones in rabbits 120 days after transplantation of the tissue-engineering construct in contrast to commercial osteoplastic materials for directed bone regeneration.

  13. Calcium metabolism in birds.

    Science.gov (United States)

    de Matos, Ricardo

    2008-01-01

    Calcium is one of the most important plasma constituents in mammals and birds. It provides structural strength and support (bones and eggshell) and plays vital roles in many of the biochemical reactions in the body. The control of calcium metabolism in birds is highly efficient and closely regulated in a number of tissues, primarily parathyroid gland, intestine, kidney, and bone. The hormones with the greatest involvement in calcium regulation in birds are parathyroid hormone, 1,25-dihydroxyvitamin D(3) (calcitriol), and estrogen, with calcitonin playing a minor and uncertain role. The special characteristics of calcium metabolism in birds, mainly associated with egg production, are discussed, along with common clinical disorders secondary to derangements in calcium homeostasis.

  14. Lithium prevents early cytosolic calcium increase and secondary injurious calcium overload in glycolytically inhibited endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Bosche, Bert, E-mail: bert.bosche@uk-essen.de [Department of Neurology, University of Duisburg-Essen (Germany); Max Planck Institute for Neurological Research with Klaus-Joachim-Zülch Laboratories of the Max Planck Society and the Medical Faculty of the University of Cologne (Germany); Schäfer, Matthias, E-mail: matthias.schaefer@sanofi.com [Institute of Physiology, Justus-Liebig-University Giessen (Germany); Graf, Rudolf, E-mail: rudolf.graf@nf.mpg.de [Max Planck Institute for Neurological Research with Klaus-Joachim-Zülch Laboratories of the Max Planck Society and the Medical Faculty of the University of Cologne (Germany); Härtel, Frauke V., E-mail: frauke.haertel@tu-dresden.de [Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden (Germany); Schäfer, Ute, E-mail: ute.schaefer@medunigraz.at [Research Unit for Experimental Neurotraumatology, Medical University of Graz (Austria); Noll, Thomas, E-mail: thomas.noll@tu-dresden.de [Institute of Physiology, Medical Faculty Carl Gustav Carus, Technical University Dresden (Germany)

    2013-05-03

    Highlights: •We investigate free calcium as a central signalling element in endothelial cells. •Inhibition of glycolysis with 2-deoxy-D-glucose reduces cellular ATP. •This manoeuvre leads to a biphasic increase and overload of free calcium. •Pre-treatment with lithium for 24 h abolishes both phases of the calcium increase. •This provides a new strategy to protect endothelial calcium homeostasis and barrier function. -- Abstract: Cytosolic free calcium concentration ([Ca{sup 2+}]{sub i}) is a central signalling element for the maintenance of endothelial barrier function. Under physiological conditions, it is controlled within narrow limits. Metabolic inhibition during ischemia/reperfusion, however, induces [Ca{sup 2+}]{sub i} overload, which results in barrier failure. In a model of cultured porcine aortic endothelial monolayers (EC), we addressed the question of whether [Ca{sup 2+}]{sub i} overload can be prevented by lithium treatment. [Ca{sup 2+}]{sub i} and ATP were analysed using Fura-2 and HPLC, respectively. The combined inhibition of glycolytic and mitochondrial ATP synthesis by 2-desoxy-D-glucose (5 mM; 2-DG) plus sodium cyanide (5 mM; NaCN) caused a significant decrease in cellular ATP content (14 ± 1 nmol/mg protein vs. 18 ± 1 nmol/mg protein in the control, n = 6 culture dishes, P < 0.05), an increase in [Ca{sup 2+}]{sub i} (278 ± 24 nM vs. 71 ± 2 nM in the control, n = 60 cells, P < 0.05), and the formation of gaps between adjacent EC. These observations indicate that there is impaired barrier function at an early state of metabolic inhibition. Glycolytic inhibition alone by 10 mM 2-DG led to a similar decrease in ATP content (14 ± 2 nmol/mg vs. 18 ± 1 nmol/mg in the control, P < 0.05) with a delay of 5 min. The [Ca{sup 2+}]{sub i} response of EC was biphasic with a peak after 1 min (183 ± 6 nM vs. 71 ± 1 nM, n = 60 cells, P < 0.05) followed by a sustained increase in [Ca{sup 2+}]{sub i}. A 24-h pre-treatment with 10 mM of lithium

  15. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free

  16. * Fabrication and Characterization of Biphasic Silk Fibroin Scaffolds for Tendon/Ligament-to-Bone Tissue Engineering.

    Science.gov (United States)

    Font Tellado, Sònia; Bonani, Walter; Balmayor, Elizabeth R; Foehr, Peter; Motta, Antonella; Migliaresi, Claudio; van Griensven, Martijn

    2017-08-01

    Tissue engineering is an attractive strategy for tendon/ligament-to-bone interface repair. The structure and extracellular matrix composition of the interface are complex and allow for a gradual mechanical stress transfer between tendons/ligaments and bone. Thus, scaffolds mimicking the structural features of the native interface may be able to better support functional tissue regeneration. In this study, we fabricated biphasic silk fibroin scaffolds designed to mimic the gradient in collagen molecule alignment present at the interface. The scaffolds had two different pore alignments: anisotropic at the tendon/ligament side and isotropic at the bone side. Total porosity ranged from 50% to 80% and the majority of pores (80-90%) were ligament, enthesis, and cartilage markers significantly changed depending on pore alignment in each region of the scaffolds. In conclusion, the biphasic scaffolds fabricated in this study show promising features for tendon/ligament-to-bone tissue engineering.

  17. Anti-prelog reduction of prochiral carbonyl compounds by Oenococcus oeni in a biphasic system.

    Science.gov (United States)

    Hu, Jian; Xu, Yan

    2006-07-01

    An aqueous-organic biphasic system was established and used with whole cells of Oenococcus oeni to reduce 2-octanone to (R)-2-octanol. The conversion reached 99% when the Tris/borate buffer was increased from 50 mM to 300 mM in the aqueous phase. In addition, the conversion increased as the log P value of the organic solvent changed from 0.5 to 6.6. Under optimized conditions, the conversion of (R)-2-octanol reached 99% from 0.5 M 2-octanone with an optical purity of 99% e.e. The biphasic system allows the anti-Prelog reduction of aliphatic and aromatic ketones to furnish (R)-configurated alcohols in high optical purity as well.

  18. Efficacy and safety of biphasic insulin aspart and biphasic insulin lispro mix in patients with type 2 diabetes: A review of the literature

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2016-01-01

    Full Text Available Type 2 diabetes (T2D represents an escalating burden worldwide, particularly in China and India. Compared with Caucasians, Asian people with diabetes have lower body mass index, increased visceral adiposity, and postprandial glucose (PPG/insulin resistance. Since postprandial hyperglycemia contributes significantly to total glycemic burden and is associated with heightened cardiovascular risk, targeting PPG early in T2D is paramount. Premixed insulin regimens are widely used in Asia due to their convenience and effectiveness. Data from randomized controlled trials and observational studies comparing efficacy and safety of biphasic insulin aspart 30 (BIAsp 30 with biphasic insulin lispro mix (LM 25/50 and versus other insulin therapies or oral antidiabetic drugs (OADs in T2D demonstrated that BIAsp 30 and LM 25/50 were associated with similar or greater improvements in glycemic control versus comparator regimens, such as basal–bolus insulin, in insulin-naÏve, and prior insulin users. Studies directly comparing BIAsp 30 and LM 25 provided conflicting glycemic control results. Safety data generally showed increased hypoglycemia and weight gain with premixed insulins versus basal–bolus insulin or OADs. However, large observational trials documented improvements in glycated hemoglobin, PPG, and hypoglycemia with BIAsp 30 in multi-ethnic patient populations. In summary, this literature review demonstrates that premixed insulin regimens are an appropriate and effective treatment choice in T2D.

  19. Development of Modified-Release Tablets of Zolpidem Tartrate by Biphasic Quick/Slow Delivery System

    OpenAIRE

    Mahapatra, Anjan Kumar; Sameeraja, N. H.; Murthy, P. N.

    2014-01-01

    Zolpidem tartrate is a non-benzodiazepine analogue of imidazopyridine of sedative and hypnotic category. It has a short half-life with usual dosage regimen being 5 mg, two times a day, or 10 mg, once daily. The duration of action is considered too short in certain circumstances. Thus, it is desirable to lengthen the duration of action. The formulation design was implemented by preparing extended-release tablets of zolpidem tartrate using the biphasic delivery system technology, where sodium s...

  20. A phenomenological model of the electrically stimulated auditory nerve fiber: temporal and biphasic response properties

    Directory of Open Access Journals (Sweden)

    Colin eHorne

    2016-02-01

    Full Text Available We present a phenomenological model of electrically stimulated auditory nerve fibers (ANFs. The model reproduces the probabilistic and temporal properties of the ANF response to both monophasic and biphasic stimuli, in isolation. The main contribution of the model lies in its ability to reproduce statistics of the ANF response (mean latency, jitter, and firing probability under both monophasic and cathodic-anodic biphasic stimulation, without changing the model’s parameters. The response statistics of the model depend on stimulus level and duration of the stimulating pulse, reproducing trends observed in the ANF. In the case of biphasic stimulation, the model reproduces the effects of pseudomonophasic pulse shapes and also the dependence on the interphase gap (IPG of the stimulus pulse, an effect that is quantitatively reproduced. The model is fitted to ANF data using a procedure that uniquely determines each model parameter. It is thus possible to rapidly parameterize a large population of neurons to reproduce a given set of response statistic distributions.Our work extends the stochastic leaky integrate and fire (SLIF neuron, a well-studied phenomenological model of the electrically stimulated neuron. We extend the SLIF neuron so as to produce a realistic latency distribution by delaying the moment of spiking. During this delay, spiking may be abolished by anodic current. By this means, the probability of the model neuron responding to a stimulus is reduced when a trailing phase of opposite polarity is introduced. By introducing a minimum wait period that must elapse before a spike may be emitted, the model is able to reproduce the differences in the threshold level observed in the ANF for monophasic and biphasic stimuli. Thus, the ANF response to a large variety of pulse shapes are reproduced correctly by this model.

  1. Preparation of highly infective Leishmania promastigotes by cultivation on SNB-9 biphasic medium

    Czech Academy of Sciences Publication Activity Database

    Grekov, Igor; Svobodová, M.; Nohýnková, E.; Lipoldová, Marie

    2011-01-01

    Roč. 87, č. 3 (2011), s. 273-277 ISSN 0167-7012 R&D Projects: GA MŠk(CZ) LC06009; GA ČR GA310/08/1697 Institutional research plan: CEZ:AV0Z50520514 Keywords : Leishmania * SNB-9 * biphasic culture medium * parasite infectivity Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.086, year: 2011

  2. A simulation study of the reaction of human heart to biphasic electrical shocks

    Directory of Open Access Journals (Sweden)

    Seemann Gunnar

    2004-06-01

    Full Text Available Abstract Background This article presents a study, which examines the effects of biphasic electrical shocks on human ventricular tissue. The effects of this type of shock are not yet fully understood. Animal experiments showed the superiority of biphasic shocks over monophasic ones in defibrillation. A mathematical computer simulation can increase the knowledge of human heart behavior. Methods The research presented in this article was done with different models representing a three-dimensional wedge of ventricular myocardium. The electrophysiology was described with Priebe-Beuckelmann model. The realistic fiber twist, which is specific to human myocardium was included. Planar electrodes were placed at the ends of the longest side of the virtual cardiac wedge, in a bath medium. They were sources of electrical shocks, which varied in magnitude from 0.1 to 5 V. In a second arrangement ring electrodes were placed directly on myocardium for getting a better view on secondary electrical sources. The electrical reaction of the tissue was generated with a bidomain model. Results The reaction of the tissue to the electrical shock was specific to the initial imposed characteristics. Depolarization appeared in the first 5 ms in different locations. A further study of the cardiac tissue behavior revealed, which features influence the response of the considered muscle. It was shown that the time needed by the tissue to be totally depolarized is much shorter when a biphasic shock is applied. Each simulation ended only after complete repolarization was achieved. This created the possibility of gathering information from all states corresponding to one cycle of the cardiac rhythm. Conclusions The differences between the reaction of the homogeneous tissue and a tissue, which contains cleavage planes, reveals important aspects of superiority of biphasic pulses. ...

  3. Work Stress and Alcohol Use: Developing and Testing a Biphasic Self-Medication Model

    OpenAIRE

    Frone, Michael R.

    2016-01-01

    This study developed and tested a moderated-mediation model of work stress and alcohol use, based on the biphasic (stimulant and sedative) effects of alcohol and the self-medication and stress-vulnerability models of alcohol use. The model proposes that exposure to work stressors can increase both negative affect and work fatigue, and that these two sources of strain can subsequently motivate the use of alcohol. However, the relations of negative affect and work fatigue to a...

  4. Use of Respiratory Support in the Biphase Ventilation Airway Mode in the Newborn

    OpenAIRE

    S. N. Koval; A. Ye. Kulagin

    2006-01-01

    Biphasic positive airway pressure (BIPAP) (also known as DuoPAP, BiLevel, BiVent, PCV+, SPAP) is a mode of ventilation with cycling variations between two continuous positive airway pressure levels. It is a mixture of pressure controlled ventilation and spontaneous breathing, which is unrestricted in each phase of the respiratory cycle. The volume displacement caused by the difference between Phigh and Plow airway pressure level. The phase time ratio (PTR — the BIPAP frequency) is calculated ...

  5. A case of mumps-related acute encephalopathy with biphasic seizures and late reduced diffusion.

    Science.gov (United States)

    Hazama, Kyoko; Shiihara, Takashi; Tsukagoshi, Hiroyuki; Hasegawa, Shunji; Dowa, Yuri; Watanabe, Mio

    2017-10-01

    Mumps is a common childhood viral disease characterized by fever and swelling of the parotid gland. The prognosis is generally good, although some complications, such as encephalitis (0.1%), exist. Acute encephalopathy with biphasic seizures and late reduced diffusion is the most common type of acute encephalopathy. However, this type of encephalopathy has not been reported in association with mumps infection. A previously healthy 3-year-old Japanese boy had a brief convulsion after fever for 3days, and then had conscious disturbance and parotitis. After several days, he had a second brief convulsion and was admitted. Increased serum amylase levels and presence of anti-mumps immunoglobulin M antibody confirmed mumps parotitis. The patient had another brief seizure later the day of admission. He did not have status or cluster seizures, although the biphasic nature of his seizures, conscious disturbance between the seizures, no pleocytosis in cerebrospinal fluid, and brain magnetic resonance images were consistent with acute encephalopathy with biphasic seizures and late reduced diffusion. In Japan, the mumps vaccine is not administered as a part of routine immunizations. It thus has low coverage (30-40%), and as a result, mumps infections are still common. However, this is the first case of mumps-related acute encephalopathy with biphasic seizures and late reduced diffusion. This case may be representative of only a minority of patients with mumps-associated central nervous system involvement. Nevertheless, this diagnostic possibility may be considered. In order to prevent mumps-related complications, routine mumps vaccination might be warranted. Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  6. Investigation of the transport properties of metals in the biphase region

    International Nuclear Information System (INIS)

    Oreshkin, V. I.; Rousskikh, A. G.; Chaikovsky, S. A.; Oreshkin, E. V.

    2010-01-01

    Results of experiments on electrical wire explosion are presented and processes of stratum formation and decay are analyzed in this paper. A procedure of calculating the transport coefficients from the rate of stratum damping is described. It is demonstrated that values of the transport coefficients for metals are not an unambiguous function of the material state in the biphase region for characteristic times of ∼10 -7 s but depend on the process prehistory.

  7. Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Ataol, Sibel; Tezcaner, Ayşen [Middle East Technical University, Department of Biomedical Engineering (Turkey); Duygulu, Ozgur [TUBITAK Marmara Research Center, Materials Institute (Turkey); Keskin, Dilek [Middle East Technical University, Department of Biomedical Engineering (Turkey); Machin, Nesrin E., E-mail: nesrinmachin@gmail.com [Kocaeli University, Department of Chemical Engineering (Turkey)

    2015-02-15

    The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20–2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA–DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5–50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications.

  8. Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

    Science.gov (United States)

    Ataol, Sibel; Tezcaner, Ayşen; Duygulu, Ozgur; Keskin, Dilek; Machin, Nesrin E.

    2015-02-01

    The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20-2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA-DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5-50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications.

  9. CO2 Absorption by Biphasic Solvents: Comparison with Lower Phase Alone

    International Nuclear Information System (INIS)

    Xu, Zhicheng; Wang, Shujuan; Qi, Guojie; Liu, Jinzhao; Zhao, Bo; Chen, Changhe

    2014-01-01

    The mixtures of 2 M 1,4-butanediamine (BDA) and 4 M 2-(diethylamino)-ethanol (DEEA) have been found to be promising biphasic solvents. This work identifies the composition of the lower phase using a DX-120 Ion Chromatograph (IC) and a Metrohm 809 Titrando auto titrator. The cyclic capacities, cyclic loadings and reaction products of the biphasic solvent are compared with those of the aqueous solution with the same amine concentration as the lower phase of the biphasic solvent at the rich loading ((2B4D) L ) using a fast screening facility and a JNM ECA-600 Nuclear Magnetic Resonance spectrometer (NMR). Their absorption rates at different loadings are also investigated using a Wetted Wall Column (WWC). The results show that the cyclic capacity and cyclic loading of (2B4D) L are almost the same as those of 2B4D. The absorption rate of (2B4D) L is higher than 2B4D at all the 3 tested loadings, except for the fresh solutions at CO 2 pressure lower than 10 kPa. NMR results show that the reaction products of (2B4D) L had more BDA bi-carbamate, less BDA and less BDA carbamate than 2B4D. The CO 2 reaction products of (2B4D) L had twice as much carbonate/bicarbonate as with 2B4D and less BDA carbamate. (authors)

  10. Paired Associative Stimulation Targeting the Tibialis Anterior Muscle using either Mono or Biphasic Transcranial Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    Natalie Mrachacz-Kersting

    2017-04-01

    Full Text Available Paired associative stimulation (PAS protocols induce plastic changes within the motor cortex. The objectives of this study were to investigate PAS effects targeting the tibialis anterior (TA muscle using a biphasic transcranial magnetic stimulation (TMS pulse form and, to determine whether a reduced intensity of this pulse would lead to significant changes as has been reported for hand muscles using a monophasic TMS pulse. Three interventions were investigated: (1 suprathreshold PAbi-PAS (n = 11; (2 suprathreshold PAmono-PAS (n = 11 where PAS was applied using a biphasic or monophasic pulse form at 120% resting motor threshold (RMT; (3 subthreshold PAbi-PAS (n = 10 where PAS was applied as for (1 at 95% active motor threshold (AMT. The peak-to-peak motor evoked potentials (MEPs were quantified prior to, immediately following, and 30 min after the cessation of the intervention. TA MEP size increased significantly for all interventions immediately post (61% for suprathreshold PAbi-PAS, 83% for suprathreshold PAmono-PAS, 55% for subthreshold PAbi-PAS and 30 min after the cessation of the intervention (123% for suprathreshold PAbi-PAS, 105% for suprathreshold PAmono-PAS, 80% for subthreshold PAbi-PAS. PAS using a biphasic pulse form at subthreshold intensities induces similar effects to conventional PAS.

  11. Comparison of the lysis-centrifugation and agitated biphasic blood culture systems for detection of fungemia.

    Science.gov (United States)

    Murray, P R

    1991-01-01

    Although the detection of fungemia has been improved by the use of vented or biphasic blood culture bottles, the best recovery and earliest detection have been reported in the Isolator lysis-centrifugation system. It was recently demonstrated that improved detection of both bacteria and fungi was accomplished by mechanically agitating blood culture bottles for the first 24 h of incubation. In this study the detection of fungemia by use of the Isolator system was compared with that of an agitated biphasic system. A total of 182 fungi were isolated from blood specimens inoculated into both culture systems. No difference in the overall recovery of fungi or individual species of yeasts was observed between the two systems. However, all seven isolates of Histoplasma capsulatum were recovered in the Isolator system only. The time required to detect fungemia with each of the two systems was also compared. No statistically significant difference was observed. From the data collected during this 18-month study, it can be concluded that the overall recovery and time of detection of yeasts are equivalent in the lysis-centrifugation system and the agitated biphasic blood culture system. The lysis-centrifugation system is still superior for the detection of filamentous fungi such as H. capsulatum. PMID:1993772

  12. Predictive feedback can account for biphasic responses in the lateral geniculate nucleus.

    Directory of Open Access Journals (Sweden)

    Janneke F M Jehee

    2009-05-01

    Full Text Available Biphasic neural response properties, where the optimal stimulus for driving a neural response changes from one stimulus pattern to the opposite stimulus pattern over short periods of time, have been described in several visual areas, including lateral geniculate nucleus (LGN, primary visual cortex (V1, and middle temporal area (MT. We describe a hierarchical model of predictive coding and simulations that capture these temporal variations in neuronal response properties. We focus on the LGN-V1 circuit and find that after training on natural images the model exhibits the brain's LGN-V1 connectivity structure, in which the structure of V1 receptive fields is linked to the spatial alignment and properties of center-surround cells in the LGN. In addition, the spatio-temporal response profile of LGN model neurons is biphasic in structure, resembling the biphasic response structure of neurons in cat LGN. Moreover, the model displays a specific pattern of influence of feedback, where LGN receptive fields that are aligned over a simple cell receptive field zone of the same polarity decrease their responses while neurons of opposite polarity increase their responses with feedback. This phase-reversed pattern of influence was recently observed in neurophysiology. These results corroborate the idea that predictive feedback is a general coding strategy in the brain.

  13. Low-High and High-Low Biphasic Injection Forms in Computed Tomography Examinations of the Upper Abdomen

    International Nuclear Information System (INIS)

    Marti-Bonmati, L.; Arana, E.; Tobarra, E.; Sierra, C.

    2006-01-01

    Purpose: To analyze the influence of different biphasic and monophasic injection rate protocols in abdominal computed tomography (CT). Material and Methods: A randomized, consecutive, parallel group study was designed and conducted in 60 patients studied with the same CT helical protocol. Patients were randomly distributed into three groups: (A) monophasic (120 ml at 2.5 ml/s); (B) low-high biphasic (120 ml, first 60 ml at a rate of 2 ml/s, the other 60 ml at 2.5 ml/s); and (C) high-low biphasic (120 ml, first 60 ml at a rate of 2.5 ml/s, the other 60 ml at 2 ml/s). All patients were injected with 300 mg I/ml non-ionic contrast media at a fixed delay time of 55 s. Contrast enhancement efficacy was evaluated by attenuation coefficient measurements. Results: Although non-significant, monophasic protocol enhancements were higher than biphasic protocol enhancements in all measurements except aortic bifurcation (p = 0.003). At this level, biphasic protocols obtained an increased mean enhancement from 7.6% to 2.5% compared to monophasic protocols. Conclusion: Monophasic contrast agent injection in helical CT of the upper abdomen produces a higher enhancement of parenchymal and venous structures. No significant difference was observed between low-high and high-low biphasic protocols

  14. Calcium Concentration in Culture Medium as a Nondestructive and Rapid Marker of Osteogenesis.

    Science.gov (United States)

    Tanikake, Yohei; Akahane, Manabu; Furukawa, Akira; Tohma, Yasuaki; Inagaki, Yusuke; Kira, Tsutomu; Tanaka, Yasuhito

    2017-06-09

    Artificial bones made of β-tricalcium phosphate (β-TCP) combined with bone marrow-derived mesenchymal stromal cells (BM-MSCs) are used for effective reconstruction of bone defects caused by genetic defects, traumatic injury, or surgical resection of bone tumors. However, the selection of constructs with high osteogenic potential before implantation is challenging. The purpose of this study was to determine whether the calcium concentration in BM-MSC culture medium can be used as a nondestructive and simple osteogenic marker for selecting tissue-engineered grafts constructed using β-TCP and BM-MSCs. We prepared three cell passages of BM-MSCs derived from three 7-week-old, male Fischer 344 rats; the cells were cultured in osteoinductive medium in the presence of β-TCP for 15 days. The medium was replaced with fresh medium on day 1 in culture and subsequently changed every 48 h; it was collected for measurement of osteocalcin secretion and calcium concentration by enzyme-linked immunosorbent assay and X-ray fluorescence spectrometry, respectively. After cultivation, the constructs were implanted subcutaneously into the backs of recipient rats. Four weeks after implantation, the alkaline phosphatase (ALP) activity and osteocalcin content of the constructs were measured. A strong inverse correlation was observed between the calcium concentration in the medium and the ALP activity and osteocalcin content of the constructs, with Pearson's correlation coefficients of 0.92 and 0.90, respectively. These results indicate that tissue-engineered bone with high osteogenic ability can be selected before implantation based on low calcium content of the culture medium, resulting in successful bone formation after implantation. This nondestructive, simple method shows great promise for assessing the osteogenic ability of tissue-engineered bone.

  15. DIHYDROPYRIDINE CALCIUM- CHANNELBLOCKERSFOR ...

    African Journals Online (AJOL)

    Furthermore, the controversy over the role of calci~-channel blockers as first-line ..... group trials while fully accounting for placebo effects as well as interindividual ..... Reducing calcium overload in the ischemic brain. N Engl JMed. 1999; 341 ...

  16. Calcium and Your Child

    Science.gov (United States)

    ... calcium-set tofu edamame (soybeans) broccoli, collard greens, kale, chard, Chinese cabbage, and other leafy greens almonds ... more dark green, leafy vegetables (such as broccoli, kale, collard greens, or Chinese cabbage) with meals. Kids ...

  17. The osteo-inductive activity of bone-marrow-derived mononuclear cells resides within the CD14+ population and is independent of the CD34+ population.

    Science.gov (United States)

    Henrich, D; Seebach, C; Verboket, R; Schaible, A; Marzi, I; Bonig, H

    2018-03-06

    Bone marrow mononuclear cells (BMC) seeded on a scaffold of β-tricalcium phosphate (β-TCP) promote bone healing in a critical-size femur defect model. Being BMC a mixed population of predominantly mature haematopoietic cells, which cell type(s) is(are) instrumental for healing remains elusive. Although clinical therapies using BMC are often dubbed as stem cell therapies, whether stem cells are relevant for the therapeutic effects is unclear and, at least in the context of bone repair, seems dubious. Instead, in light of the critical contribution of monocytes and macrophages to tissue development, homeostasis and injury repair, in the current study it was hypothesised that BMC-mediated bone healing derived from the stem cell population. To test this hypothesis, bone remodelling studies were performed in an established athymic rats critical-size femoral defect model, with β-TCP scaffolds augmented with complete BMC or BMC immunomagnetically depleted of stem cells (CD34+) or monocytes/macrophages (CD14+). Bone healing was assessed 8 weeks after transplantation. Compared to BMC-augmented controls, when CD14- BMC, but not CD34- BMC were transplanted into the bone defect, femora possessed dramatically decreased biomechanical stability and new bone formation was markedly reduced, as measured by histology. The degree of vascularisation did not differ between the two groups. It was concluded that the monocyte fraction within the BMC provided critical osteo-inductive cues during fracture healing. Which factors were responsible at the molecular levels remained elusive. However, this study marked a significant progress towards elucidating the mechanisms by which BMC elicit their therapeutic effects, at least in bone regeneration.

  18. Fabrication of poly(ethylene glycol) hydrogel micropatterns with osteoinductive growth factors and evaluation of the effects on osteoblast activity and function

    Energy Technology Data Exchange (ETDEWEB)

    Subramani, K [Institute for Nanoscale Science and Technology (INSAT), University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7AR (United Kingdom); Birch, M A [Institute for Nanoscale Science and Technology (INSAT), University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7AR (United Kingdom)

    2006-09-15

    orthopaedic applications using osteoinductive PEG hydrogel micropatterns.

  19. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    James, W.P.T.; Branch, W.J.; Southgate, D.A.T.

    1978-01-01

    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  20. Processing and properties of calcium phosphates bioceramics by hot isostatic pressing

    Directory of Open Access Journals (Sweden)

    Boilet Laurent

    2013-11-01

    Full Text Available Stoichiometric β-tricalcium phosphate (β-TCP, hydroxyapatite (HA and biphasic calcium phosphate (TCP/HA 60/40 %wt, BCP40 powders were synthesized by chemical precipitation of aqueous solutions of diammonium phosphate and calcium nitrate. After a calcination treatment and a milling step, powders were shaped by slip-casting. The sintering temperature effect on the density and the average grain size was investigated. By natural sintering, densities between 98 and 99.8% were obtained. Hot Isostatic Pressing (HIP treatment was carried out after a pre-sintering of these materials. Transparent or translucent samples were obtained, indicating a relative density very close to the theoretical value (>99.9%. Mechanical properties (three-point bending strength, fracture toughness, Young's modulus and Vickers hardness were measured on hipped materials with similar grain size (∼0.7μm.

  1. Operation and Performance of a Biphase Turbine Power Plant at the Cerro Prieto Geothermal Field (Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Lance G. [Douglas Energy Company, Placentia, CA (United States)

    2000-09-01

    A full scale, wellhead Biphase turbine was manufactured and installed with the balance of plant at Well 103 of the Cerro Prieto geothermal resource in Baja, California. The Biphase turbine was first synchronized with the electrical grid of Comision Federal de Electricidad on August 20, 1997. The Biphase power plant was operated from that time until May 23, 2000, a period of 2 years and 9 months. A total of 77,549 kWh were delivered to the grid. The power plant was subsequently placed in a standby condition pending replacement of the rotor with a newly designed, higher power rotor and replacement of the bearings and seals. The maximum measured power output of the Biphase turbine, 808 kWe at 640 psig wellhead pressure, agreed closely with the predicted output, 840 kWe. When combined with the backpressure steam turbine the total output power from that flow would be increased by 40% above the power derived only from the flow by the present flash steam plant. The design relations used to predict performance and design the turbine were verified by these tests. The performance and durability of the Biphase turbine support the conclusion of the Economics and Application Report previously published, (Appendix A). The newly designed rotor (the Dual Pressure Rotor) was analyzed for the above power condition. The Dual Pressure Rotor would increase the power output to 2064 kWe by incorporating two pressure letdown stages in the Biphase rotor, eliminating the requirement for a backpressure steam turbine. The power plant availability was low due to deposition of solids from the well on the Biphase rotor and balance of plant problems. A great deal of plant down time resulted from the requirement to develop methods to handle the solids and from testing the apparatus in the Biphase turbine. Finally an online, washing method using the high pressure two-phase flow was developed which completely eliminated the solids problem. The availability of the Biphase turbine itself was 100

  2. A model of propagating calcium-induced calcium release mediated by calcium diffusion

    NARCIS (Netherlands)

    Backx, P. H.; de Tombe, P. P.; van Deen, J. H.; Mulder, B. J.; ter Keurs, H. E.

    1989-01-01

    The effect of sudden local fluctuations of the free sarcoplasmic [Ca++]i in cardiac cells on calcium release and calcium uptake by the sarcoplasmic reticulum (SR) was calculated with the aid of a simplified model of SR calcium handling. The model was used to evaluate whether propagation of calcium

  3. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    NARCIS (Netherlands)

    Jonge, H.J. de; Gans, R.O.; Huls, G.A.

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate

  4. Production and characterization of setting hydraulic cements based on calcium phosphate; Obtencao e caracterizacao de cimentos de fosfato de calcio de pega hidraulica

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luci C. de; Rigo, Eliana C.S.; Santos, Luis A dos; Boschi, Anselmo Ortega [Sao Carlos Univ., SP (Brazil). Dept. de Engenharia de Materiais; Carrodeguas, Raul G. [Universidad de La Habana, Habana (Cuba). Centro de Biomateriales

    1997-12-31

    Setting hydraulic cements based on calcium phosphate has risen great interest in scientific literature during recent years due to their total bio compatibility and to the fact that they harden `in situ`, providing easy handling and adaptation to the shape and dimensions of the defect which requires correction, differently from the predecessors, the calcium phosphate ceramics (Hydroxy apatite, {beta}-tri calcium phosphate, biphasic, etc) in the shape of dense or porous blocks and grains. In the work, three calcium-phosphate cement compositions were studied. The resulting compositions were characterized according to the following aspects: setting times, pH, mechanical resistance, crystalline phases, microstructure and solubility in SBF (Simulated Body Fluid). The results show a potential use for the compositions. (author) 6 figs., 4 tabs.

  5. Biphasic papillary renal cell carcinoma is a rare morphological variant with frequent multifocality: a study of 28 cases.

    Science.gov (United States)

    Trpkov, Kiril; Athanazio, Daniel; Magi-Galluzzi, Cristina; Yilmaz, Helene; Clouston, David; Agaimy, Abbas; Williamson, Sean R; Brimo, Fadi; Lopez, Jose I; Ulamec, Monika; Rioux-Leclercq, Nathalie; Kassem, Maysoun; Gupta, Nilesh; Hartmann, Arndt; Leroy, Xavier; Bashir, Samir Al; Yilmaz, Asli; Hes, Ondřej

    2018-04-01

    To further characterise biphasic squamoid renal cell carcinoma (RCC), a recently proposed variant of papillary RCC. We identified 28 tumours from multiple institutions. They typically showed two cell populations-larger cells with eosinophilic cytoplasm and higher-grade nuclei, surrounded by smaller, amphophilic cells with scanty cytoplasm. The dual morphology was variable (median 72.5% of tumour, range 5-100%); emperipolesis was found in all cases. The male/female ratio was 2:1, and the median age was 55 years (range 39-86 years). The median tumour size was 20 mm (range 9-65 mm). Pathological stage pT1a was found in 21 cases, pT1b in three, and pT3a and pT3b in one each (two not available). Multifocality was found in 32%: multifocal biphasic RCC in one case, biphasic + papillary RCC in two cases, biphasic + clear cell RCC in three cases, biphasic + low-grade urothelial carcinoma of the renal pelvis in one case, and biphasic + Birt-Hogg-Dubé syndrome in one case. Positive immunostains included: PAX8, cytokeratin (CK) 7, α-methylacyl-CoA racemase, epithelial membrane antigen, and vimentin. Cyclin D1 was expressed only in the larger cells. The Ki67 index was higher in the larger cells (median 5% versus ≤1%). Negative stains included: carbonic anhydrase 9, CD117, GATA-3, WT1, CK5/6, and CK20; CD10 and 34βE12 were variably expressed. Gains of chromosomes 7 and 17 were found in two evaluated cases. Follow-up was available for 23 patients (median 24 months, range 1-244 months): 19 were alive without disease, one was alive with recurrence, and one had died of disease (two had died of other causes). Biphasic papillary RCC is a rare variant of papillary RCC, and is often multifocal. © 2017 John Wiley & Sons Ltd.

  6. Switching from biphasic human insulin to biphasic insulin aspart 30 in type 2 diabetes: results from the ASEAN subgroup of the A₁chieve study.

    Science.gov (United States)

    Hussein, Zanariah; Lim-Abrahan, Mary Anne; Jain, Anand B; Goh, Su Yen; Soewondo, Pradana

    2013-04-01

    To evaluate the safety and effectiveness of biphasic insulin aspart 30 (BIAsp 30) in ASEAN type 2 diabetes (T2D) patients switched from biphasic human insulin (BHI) in the non-interventional 24-week A₁chieve study. Indonesian, Malaysian, Filipino and Singaporean patients switched from BHI to BIAsp 30 at their physicians' discretion were included. The incidence of serious adverse drug reactions (SADRs), including major hypoglycaemia was the primary endpoint. Changes in hypoglycaemia, glycated haemoglobin A1c (HbA1c), fasting plasma glucose (FPG), postprandial plasma glucose (PPPG), lipids, body weight and systolic blood pressure were also evaluated. Quality of life (QoL) was measured using the EQ-5D questionnaire. For the 465 patients included (mean ± SD age: 56 ± 10.3 years, diabetes duration: 9.7 ± 7.1 years, baseline HbA1c: 9.4 ± 1.8%), the mean pre-study BHI dose was 0.62 ± 0.28 IU/kg and 63.4% were dosing BHI twice daily (bid). The mean baseline BIAsp 30 dose was 0.65 ± 0.27 U/kg, titrated up to 0.71 ± 0.28 U/kg over 24 weeks, and most patients continued bid dosing. No SADRs or major hypoglycaemic episodes were reported. The proportion of patients reporting overall hypoglycaemia decreased significantly from 10.8% at baseline to 3.4% at Week 24 (p ASEAN subgroup poorly controlled on BHI. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  7. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  8. A Human Clinical, Histological, Histomorphometrical, and Radiographical Study on Biphasic HA-Beta-TCP 30/70 in Maxillary Sinus Augmentation.

    Science.gov (United States)

    Mangano, Carlo; Sinjari, Bruna; Shibli, Jamil A; Mangano, Francesco; Hamisch, Sabine; Piattelli, Adriano; Perrotti, Vittoria; Iezzi, Giovanna

    2015-06-01

    By mixing hydroxyapatite (HA) and tricalcium phosphate (TCP), biphasic calcium phosphate ceramics can be obtained, and by varying their ratio it is possible to tailor the characteristics of the biomaterial. The aim of the present human study was to evaluate the histological and radiographical aspects of bone formation in maxillary sinus augmentation using a 30/70 HA-beta-TCP with a reticular structure. A total of 12 patients, undergoing two-stage sinus augmentation procedure using HA-beta-TCP at a ratio of 30/70, were included in the present study. After a 6-month healing period, during implant insertion, radiographical analysis was performed, and then the bone core biopsies were harvested and processed for histology. At radiographic evaluation, the bone gain was on average 6.85 ± 0.60 mm. HA-beta-TCP 30/70 appeared to be lined by newly formed bone, with no gaps at the interface. The histomorphometric analysis revealed 26 ± 2% of residual grafted biomaterial, 29 ± 3% of newly formed bone, and 45 ± 2% of marrow spaces. The present results indicate histologically the high biocompatibility and osteoconductivity of HA-beta-TCP 30/70, and clinically its successful use for sinus augmentation procedures. © 2013 Wiley Periodicals, Inc.

  9. Calcium-containing scaffolds induce bone regeneration by regulating mesenchymal stem cell differentiation and migration.

    Science.gov (United States)

    Aquino-Martínez, Rubén; Angelo, Alcira P; Pujol, Francesc Ventura

    2017-11-16

    Osteoinduction and subsequent bone formation rely on efficient mesenchymal stem cell (MSC) recruitment. It is also known that migration is induced by gradients of growth factors and cytokines. Degradation of Ca 2+ -containing biomaterials mimics the bone remodeling compartment producing a localized calcium-rich osteoinductive microenvironment. The aim of our study was to determine the effect of calcium sulfate (CaSO 4 ) on MSC migration. In addition, to evaluate the influence of CaSO 4 on MSC differentiation and the potential molecular mechanisms involved. A circular calvarial bone defect (5 mm diameter) was created in the parietal bone of 35 Balb-C mice. We prepared and implanted a cell-free agarose/gelatin scaffold alone or in combination with different CaSO 4 concentrations into the bone defects. After 7 weeks, we determined the new bone regenerated by micro-CT and histological analysis. In vitro, we evaluated the CaSO 4 effects on MSC migration by both wound healing and agarose spot assays. Osteoblastic gene expression after BMP-2 and CaSO 4 treatment was also evaluated by qPCR. CaSO 4 increased MSC migration and bone formation in a concentration-dependent manner. Micro-CT analysis showed that the addition of CaSO 4 significantly enhanced bone regeneration compared to the scaffold alone. The histological evaluation confirmed an increased number of endogenous cells recruited into the cell-free CaSO 4 -containing scaffolds. Furthermore, MSC migration in vitro and active AKT levels were attenuated when CaSO 4 and BMP-2 were in combination. Addition of LY294002 and Wortmannin abrogated the CaSO 4 effects on MSC migration. Specific CaSO 4 concentrations induce bone regeneration of calvarial defects in part by acting on the host's undifferentiated MSCs and promoting their migration. Progenitor cell recruitment is followed by a gradual increment in osteoblast gene expression. Moreover, CaSO 4 regulates BMP-2-induced MSC migration by differentially activating the PI3

  10. Calcium-containing scaffolds induce bone regeneration by regulating mesenchymal stem cell differentiation and migration

    Directory of Open Access Journals (Sweden)

    Rubén Aquino-Martínez

    2017-11-01

    Full Text Available Abstract Background Osteoinduction and subsequent bone formation rely on efficient mesenchymal stem cell (MSC recruitment. It is also known that migration is induced by gradients of growth factors and cytokines. Degradation of Ca2+-containing biomaterials mimics the bone remodeling compartment producing a localized calcium-rich osteoinductive microenvironment. The aim of our study was to determine the effect of calcium sulfate (CaSO4 on MSC migration. In addition, to evaluate the influence of CaSO4 on MSC differentiation and the potential molecular mechanisms involved. Methods A circular calvarial bone defect (5 mm diameter was created in the parietal bone of 35 Balb-C mice. We prepared and implanted a cell-free agarose/gelatin scaffold alone or in combination with different CaSO4 concentrations into the bone defects. After 7 weeks, we determined the new bone regenerated by micro-CT and histological analysis. In vitro, we evaluated the CaSO4 effects on MSC migration by both wound healing and agarose spot assays. Osteoblastic gene expression after BMP-2 and CaSO4 treatment was also evaluated by qPCR. Results CaSO4 increased MSC migration and bone formation in a concentration-dependent manner. Micro-CT analysis showed that the addition of CaSO4 significantly enhanced bone regeneration compared to the scaffold alone. The histological evaluation confirmed an increased number of endogenous cells recruited into the cell-free CaSO4-containing scaffolds. Furthermore, MSC migration in vitro and active AKT levels were attenuated when CaSO4 and BMP-2 were in combination. Addition of LY294002 and Wortmannin abrogated the CaSO4 effects on MSC migration. Conclusions Specific CaSO4 concentrations induce bone regeneration of calvarial defects in part by acting on the host’s undifferentiated MSCs and promoting their migration. Progenitor cell recruitment is followed by a gradual increment in osteoblast gene expression. Moreover, CaSO4 regulates BMP-2-induced

  11. Three dimensional printed calcium phosphate and poly(caprolactone) composites with improved mechanical properties and preserved microstructure.

    Science.gov (United States)

    Vella, Joseph B; Trombetta, Ryan P; Hoffman, Michael D; Inzana, Jason; Awad, Hani; Benoit, Danielle S W

    2018-03-01

    Biphasic calcium phosphate scaffolds formed via three dimensional (3D) printing technology to exhibit porosity and chemical resorbability to promote osseointegration often lack the strength and toughness required to withstand loading in bone tissue engineering applications. Herein, sintering and CaP:poly(caprolactone) (PCL) composite formation were explored to improve 3D printed scaffold strength and toughness. Hydroxyapatite and α-tricalcium phosphate (α-TCP) biphasic calcium powders were printed using phosphoric acid binder, which generated monetite and hydroxyapatite scaffolds. Upon sintering, evolution of β-TCP was observed along with an increase in flexural strength and modulus but no effect on fracture toughness was observed. Furthermore, scaffold porosity increased with sintering. Additionally, two techniques of PCL composite formation were employed: postprint precipitation and 3D print codeposition to further augment scaffold mechanical properties. While both techniques significantly improved flexural strength, flexural modulus, and fracture toughness under most conditions explored, precipitation yielded more substantial increases in these properties, which is attributed to better continuity of the PCL phase. However, precipitation also compromised surface porosity due to PCL passivation of the calcium phosphate surface, which may subsequently hinder scaffold integration and bone regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 663-672, 2018. © 2017 Wiley Periodicals, Inc.

  12. Combination of calcium sulfate and simvastatin-controlled release microspheres enhances bone repair in critical-sized rat calvarial bone defects

    Directory of Open Access Journals (Sweden)

    Fu YC

    2015-12-01

    Full Text Available Yin-Chih Fu,1–4 Yan-Hsiung Wang,1,5 Chung-Hwan Chen,1,3,4 Chih-Kuang Wang,1,6 Gwo-Jaw Wang,1,3,4 Mei-Ling Ho1,3,7,8 1Orthopaedic Research Center, 2Graduate Institute of Medicine, 3Department of Orthopaedics, 4Department of Orthopaedics, College of Medicine, 5School of Dentistry, College of Dental Medicine, 6Department of Medicinal and Applied Chemistry, 7Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 8Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, TaiwanAbstract: Most allogenic bone graft substitutes have only osteoconductive properties. Developing new strategies to improve the osteoinductive activity of bone graft substitutes is both critical and practical for clinical application. Previously, we developed novel simvastatin-encapsulating poly(lactic-co-glycolic acid microspheres (SIM/PLGA that slowly release simvastatin and enhance fracture healing. In this study, we combined SIM/PLGA with a rapidly absorbable calcium sulfate (CS bone substitute and studied the effect on bone healing in critical-sized calvarial bone defects in a rat model. The cytotoxicity and cytocompatibility of this combination was tested in vitro using lactate dehydrogenase leakage and a cell attachment assay, respectively. Combination treatment with SIM/PLGA and the CS bone substitute had no cytotoxic effect on bone marrow stem cells. Compared with the control, cell adhesion was substantially enhanced following combination treatment with SIM/PLGA and the CS bone substitute. In vivo, implantation of the combination bone substitute promoted healing of critical-sized calvarial bone defects in rats; furthermore, production of bone morphogenetic protein-2 and neovascularization were enhanced in the area of the defect. In summary, the combination of SIM/PLGA and a CS bone substitute has osteoconductive and osteoinductive properties, indicating that it could be used for regeneration

  13. Learning new meanings for known words: Biphasic effects of prior knowledge

    Science.gov (United States)

    Fang, Xiaoping; Perfetti, Charles; Stafura, Joseph

    2017-01-01

    In acquiring word meanings, learners are often confronted by a single word form that is mapped to two or more meanings. For example, long after how to roller-“skate”, one may learn that “skate” is also a kind of fish. Such learning of new meanings for familiar words involves two potentially contrasting processes, relative to new form-new meaning learning: 1) Form-based familiarity may facilitate learning a new meaning, and 2) meaning-based interference may inhibit learning a new meaning. We examined these two processes by having native English speakers learn new, unrelated meanings for familiar (high frequency) and less familiar (low frequency) English words, as well as for unfamiliar (novel or pseudo-) words. Tracking learning with cued-recall tasks at several points during learning revealed a biphasic pattern: higher learning rates and greater learning efficiency for familiar words relative to novel words early in learning and a reversal of this pattern later in learning. Following learning, interference from original meanings for familiar words was detected in a semantic relatedness judgment task. Additionally, lexical access to familiar words with new meanings became faster compared to their exposure controls, but no such effect occurred for less familiar words. Overall, the results suggest a biphasic pattern of facilitating and interfering processes: Familiar word forms facilitate learning earlier, while interference from original meanings becomes more influential later. This biphasic pattern reflects the co-activation of new and old meanings during learning, a process that may play a role in lexicalization of new meanings. PMID:29399593

  14. Intervertebral Disc Tissue Engineering with Natural Extracellular Matrix-Derived Biphasic Composite Scaffolds.

    Directory of Open Access Journals (Sweden)

    Baoshan Xu

    Full Text Available Tissue engineering has provided an alternative therapeutic possibility for degenerative disc diseases. However, we lack an ideal scaffold for IVD tissue engineering. The goal of this study is to fabricate a novel biomimetic biphasic scaffold for IVD tissue engineering and evaluate the feasibility of developing tissue-engineered IVD in vitro and in vivo. In present study we developed a novel integrated biphasic IVD scaffold using a simple freeze-drying and cross-linking technique of pig bone matrix gelatin (BMG for the outer annulus fibrosus (AF phase and pig acellular cartilage ECM (ACECM for the inner nucleus pulposus (NP phase. Histology and SEM results indicated no residual cells remaining in the scaffold that featured an interconnected porous microstructure (pore size of AF and NP phase 401.4 ± 13.1 μm and 231.6 ± 57.2 μm, respectively. PKH26-labeled AF and NP cells were seeded into the scaffold and cultured in vitro. SEM confirmed that seeded cells could anchor onto the scaffold. Live/dead staining showed that live cells (green fluorescence were distributed in the scaffold, with no dead cells (red fluorescence being found. The cell-scaffold constructs were implanted subcutaneously into nude mice and cultured for 6 weeks in vivo. IVD-like tissue formed in nude mice as confirmed by histology. Cells in hybrid constructs originated from PKH26-labeled cells, as confirmed by in vivo fluorescence imaging system. In conclusion, the study demonstrates the feasibility of developing a tissue-engineered IVD in vivo with a BMG- and ACECM-derived integrated AF-NP biphasic scaffold. As well, PKH26 fluorescent labeling with in vivo fluorescent imaging can be used to track cells and analyse cell--scaffold constructs in vivo.

  15. Application of aqueous biphasic systems as strategy to purify tannase from Aspergillus tamarii URM 7115.

    Science.gov (United States)

    de Sena, Amanda Reges; Barros Oliveira, Flávio Manoel; Campos Leite, Tonny Cley; Evaristo da Silva Nascimento, Talita Camila; Moreira, Keila Aparecida; de Assis, Sandra Aparecida

    2017-10-21

    The aims of the current study are to assess the influence of polyethylene glycol (PEG) concentration, molar mass, pH, and citrate concentrations on aqueous biphasic systems based on 2 4 factorial designs, as well as to check their capacity to purify tannase secreted by Aspergillus tamarii URM 7115. Tannase was produced through submerged fermentation at 26°C for 67 h in Czapeck-Dox modified broth and added with yeast extract and tannic acid. The factorial design was followed to assess the influence of PEG molar mass (M PEG 600; 4,000 and 8,000 g/ mol), and PEG (C PEG 20.0; 22.0 and 24.0% w/w) and citrate concentrations (C CIT 15.0, 17.5, and 20.0%, w/w), as well as of pH (6.0, 7.0, and 8.0) on the response variables; moreover, partition coefficient (K), yield (Y), and purification factor (PF) were analyzed. The most suitable parameters to purify tannase secreted by A. tamarii URM 7115 through a biphasic system were 600 (g/mol) M PEG , 24% (w/w) C PEG , 15% (w/w) C CIT at pH 6.0 and they resulted in 6.33 enzyme partition, 131.25% yield, 19.80 purification factor and 195.08 selectivity. Tannase secreted by A. tamarii URM 7115 purified through aqueous biphasic systems composed of PEG/citrate can be used for industrial purposes, since it presents suitable purification factor and yield.

  16. Fabrication and tritium release property of Li2TiO3-Li4SiO4 biphasic ceramics

    Science.gov (United States)

    Yang, Mao; Ran, Guangming; Wang, Hailiang; Dang, Chen; Huang, Zhangyi; Chen, Xiaojun; Lu, Tiecheng; Xiao, Chengjian

    2018-05-01

    Li2TiO3-Li4SiO4 biphasic ceramic pebbles have been developed as an advanced tritium breeder due to the potential to combine the advantages of both Li2TiO3 and Li4SiO4. Wet method was developed for the pebble fabrication and Li2TiO3-Li4SiO4 biphasic ceramic pebbles were successfully prepared by wet method using the powders synthesized by hydrothermal method. The tritium release properties of the Li2TiO3-Li4SiO4 biphasic ceramic pebbles were evaluated. The biphasic pebbles exhibited good tritium release property at low temperatures and the tritium release temperature was around 470 °C. Because of the isotope exchange reaction between H2 and tritium, the addition of 0.1%H2 to purge gas He could significantly enhance the tritium gas release and the fraction of molecular form of tritium increased from 28% to 55%. The results indicate that the Li2TiO3-Li4SiO4 biphasic ceramic pebbles fabricated by wet method exhibit good tritium release property and hold promising potential as advanced breeder pebbles.

  17. Electrochemical assessment of water|ionic liquid biphasic systems towards cesium extraction from nuclear waste

    OpenAIRE

    Stockmann, T. Jane; Zhang, Jing; Montgomery, Anne-Marie; Ding, Zhifeng

    2014-01-01

    A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P66614(+)) and tetrakis(pentafluorophenyl) borate anion (TB) was employed within a water| P66614TB (w|P66614TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. Cs-137 is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is th...

  18. New biphasic monocomponent composite material obtained by the partial oxypropylation of bacterial cellulose

    International Nuclear Information System (INIS)

    Rosa, Joyce Rover; Silva, Ingrid S.V. da; Pasquini, Daniel; Santos, Daniele B. dos; Barud, Hernane S.; Ribeiro, Sidney J.L.

    2011-01-01

    This study aimed to partial oxypropylation of bacterial cellulose (CB), as well as the characterization of pure CB, oxypropylated CB (CBO) and oxypropylated CB after Soxhlet extraction with hexane (CBOE). The oxypropylation reaction was carried out by propylene oxide polymerization, catalyzed by KOH, in the presence of CB The CB samples, before and after modification, were subjected to analysis of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was possible verify that the partial transformation of bacterial cellulose by inserting a layer of thermoplastic polymer on its surface occurred efficiently, obtaining a biphasic monocomponent composite material. (author)

  19. Calcium ferrite formation from the thermolysis of calcium tris (maleato)

    Indian Academy of Sciences (India)

    For preparing calcium ferrite, calcium tris (maleato) ferrate(III) precursor was prepared by mixing aqueous solutions of iron(III) maleate, calcium maleate and maleic acid. Various physico-chemical techniques i.e. TG, DTG, DTA, Mössbauer, XRD, IR etc have been used to study the decomposition behaviour from ambient to ...

  20. Production of Phytotoxic Metabolite Using Biphasic Fermentation System from Strain C1136 of Lasiodiplodia pseudotheobromae, a Potential Bioherbicidal Agent

    Directory of Open Access Journals (Sweden)

    Charles Oluwaseun ADETUNJI

    2017-09-01

    Full Text Available Formulation of effective and environmental friendly bioherbicides depends on the type of fermentation medium used for the production of phytotoxic metabolites. The effect of biomass, colony forming unit and the phytotoxic metabolite produced from the biphasic fermentation was carried out, while the phytotoxic metabolite was tested in vivo and in-vitro on Echinochola crus-galli and dicotyledonous Chromolaena odorata. The mutant strain of Lasiodiplodia pseudotheobromae C1136 (Lp90 produced the highest amount of conidia and the largest necrotic area on the two tested weeds when compared to its wild strain in the different biphasic media combinations. The study revealed that the biphasic system containing PDB + rice produced the highest bioherbicidal activities. Therefore, the phytotoxic metabolites from strain C1136 are suggested for large scale production of bioherbicides for the management of weeds in conventional farming to improve yield and enhance food security.

  1. Invariance of the magnetic behavior and AMI in ferromagnetic biphase films with distinct non-magnetic metallic spacers

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.F. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Gamino, M. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Instituto de Física, Universidade Federal do Rio Grande de Sul, 91501-970 Porto Alegre, RS (Brazil); Andrade, A.M.H. de [Instituto de Física, Universidade Federal do Rio Grande de Sul, 91501-970 Porto Alegre, RS (Brazil); Vázquez, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Correa, M.A. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Bohn, F., E-mail: felipebohn@fisica.ufrn.br [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

    2017-02-01

    We investigate the quasi-static magnetic, magnetotransport, and dynamic magnetic properties in ferromagnetic biphase films with distinct non-magnetic metallic spacer layers. We observe that the nature of the non-magnetic metallic spacer material does not have significant influence on the overall biphase magnetic behavior, and, consequently, on the magnetotransport and dynamic magnetic responses. We focus on the magnetoimpedance effect and verify that the films present asymmetric magnetoimpedance effect. Moreover, we explore the possibility of tuning the linear region of the magnetoimpedance curves around zero magnetic field by varying the probe current frequency in order to achieve higher sensitivity values. The invariance of the magnetic behavior and the asymmetric magnetoimpedance effect in ferromagnetic biphase films with distinct non-magnetic metallic spacers place them as promising candidates for probe element and open possibilities to the development of lower-cost high sensitivity linear magnetic field sensor devices.

  2. A sensor for calcium uptake

    Science.gov (United States)

    Collins, Sean; Meyer, Tobias

    2011-01-01

    Mitochondria — the cell’s power plants — increase their energy production in response to calcium signals in the cytoplasm. A regulator of the elusive mitochondrial calcium channel has now been identified. PMID:20844529

  3. Children's Bone Health and Calcium

    Science.gov (United States)

    ... Twitter Pinterest Email Print Children's Bone Health and Calcium: Condition Information What is bone health and how ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  4. Calcium – how and why?

    Indian Academy of Sciences (India)

    Unknown

    biological processes because of its unusual physical and chemical properties. 1. History of calcium ... cellular roles of calcium has established the importance of this ion ..... Ca2+ ion, for example in regulating enzyme activity (Price. 1975 ...

  5. Modeling and predictions of biphasic mechanosensitive cell migration altered by cell-intrinsic properties and matrix confinement.

    Science.gov (United States)

    Pathak, Amit

    2018-04-12

    Motile cells sense the stiffness of their extracellular matrix (ECM) through adhesions and respond by modulating the generated forces, which in turn lead to varying mechanosensitive migration phenotypes. Through modeling and experiments, cell migration speed is known to vary with matrix stiffness in a biphasic manner, with optimal motility at an intermediate stiffness. Here, we present a two-dimensional cell model defined by nodes and elements, integrated with subcellular modeling components corresponding to mechanotransductive adhesion formation, force generation, protrusions and node displacement. On 2D matrices, our calculations reproduce the classic biphasic dependence of migration speed on matrix stiffness and predict that cell types with higher force-generating ability do not slow down on very stiff matrices, thus disabling the biphasic response. We also predict that cell types defined by lower number of total receptors require stiffer matrices for optimal motility, which also limits the biphasic response. For a cell type with robust biphasic migration on 2D surface, simulations in channel-like confined environments of varying width and height predict faster migration in more confined matrices. Simulations performed in shallower channels predict that the biphasic mechanosensitive cell migration response is more robust on 2D micro-patterns as compared to the channel-like 3D confinement. Thus, variations in the dimensionality of matrix confinement alters the way migratory cells sense and respond to the matrix stiffness. Our calculations reveal new phenotypes of stiffness- and topography-sensitive cell migration that critically depend on both cell-intrinsic and matrix properties. These predictions may inform our understanding of various mechanosensitive modes of cell motility that could enable tumor invasion through topographically heterogeneous microenvironments. © 2018 IOP Publishing Ltd.

  6. A Physicochemically Optimized and Neuroconductive Biphasic Nerve Guidance Conduit for Peripheral Nerve Repair.

    Science.gov (United States)

    Ryan, Alan J; Lackington, William A; Hibbitts, Alan J; Matheson, Austyn; Alekseeva, Tijna; Stejskalova, Anna; Roche, Phoebe; O'Brien, Fergal J

    2017-12-01

    Clinically available hollow nerve guidance conduits (NGCs) have had limited success in treating large peripheral nerve injuries. This study aims to develop a biphasic NGC combining a physicochemically optimized collagen outer conduit to bridge the transected nerve, and a neuroconductive hyaluronic acid-based luminal filler to support regeneration. The outer conduit is mechanically optimized by manipulating crosslinking and collagen density, allowing the engineering of a high wall permeability to mitigate the risk of neuroma formation, while also maintaining physiologically relevant stiffness and enzymatic degradation tuned to coincide with regeneration rates. Freeze-drying is used to seamlessly integrate the luminal filler into the conduit, creating a longitudinally aligned pore microarchitecture. The luminal stiffness is modulated to support Schwann cells, with laminin incorporation further enhancing bioactivity by improving cell attachment and metabolic activity. Additionally, this biphasic NGC is shown to support neurogenesis and gliogenesis of neural progenitor cells and axonal outgrowth from dorsal root ganglia. These findings highlight the paradigm that a successful NGC requires the concerted optimization of both a mechanical support phase capable of bridging a nerve defect and a neuroconductive phase with an architecture capable of supporting both Schwann cells and neurons in order to achieve functional regenerative outcome. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Biopolymer-stabilized Pt nanoparticles colloid: a highly active and recyclable catalyst for biphasic catalysis

    International Nuclear Information System (INIS)

    Wang, Yujia; Shen, Yueyue; Qiu, Yunfei; Zhang, Ting; Liao, Yang; Zhao, Shilin; Ma, Jun; Mao, Hui

    2016-01-01

    Noble metal nanoparticles are promising candidates to replace conventional bulk counterparts owing to their high activity and selectivity. To enable catalyst recovery, noble metal nanoparticles are often supported onto solid matrices to prepare heterogeneous catalyst. Although recycle of noble metal nanoparticles is realized by heterogenization, a loss of activity is usually encountered. In the present investigation, Pt nanoparticles with tunable particle size (1.85–2.80 nm) were facilely prepared by using polyphenols as amphiphilic stabilizers. The as-prepared Pt nanoparticles colloid solution could be used as highly active catalyst in aqueous–organic biphasic catalysis. The phenolic hydroxyls of polyphenols could constrain Pt nanoparticles in aqueous phase, and simultaneously, the aromatic scaffold of polyphenols ensured effective interactions between substrates and Pt nanoparticles. As a consequence, the obtained polyphenols-stabilized Pt nanoparticles exhibited high activity and cycling stability in biphasic hydrogenation of a series of unsaturated compounds. Compared with conventional heterogeneous Pt-C and Pt-Al 2 O 3 catalysts, polyphenols-stabilized Pt nanoparticles showed obvious advantage both in activity and cycling stability.

  8. Aqueous biphasic extraction of uranium and thorium from contaminated soils. Final report

    International Nuclear Information System (INIS)

    Chaiko, D.J.; Gartelmann, J.; Henriksen, J.L.; Krause, T.R.; Deepak; Vojta, Y.; Thuillet, E.; Mertz, C.J.

    1995-07-01

    The aqueous biphasic extraction (ABE) process for soil decontamination involves the selective partitioning of solutes and fine particulates between two immiscible aqueous phases. The biphase system is generated by the appropriate combination of a water-soluble polymer (e.g., polyethlene glycol) with an inorganic salt (e.g., sodium carbonate). Selective partitioning results in 99 to 99.5% of the soil being recovered in the cleaned-soil fraction, while only 0.5 to 1% is recovered in the contaminant concentrate. The ABE process is best suited to the recovery of ultrafine, refractory material from the silt and clay fractions of soils. During continuous countercurrent extraction tests with soil samples from the Fernald Environmental Management Project site (Fernald, OH), particulate thorium was extracted and concentrated between 6- and 16-fold, while the uranium concentration was reduced from about 500 mg/kg to about 77 mg/kg. Carbonate leaching alone was able to reduce the uranium concentration only to 146 mg/kg. Preliminary estimates for treatment costs are approximately $160 per ton of dry soil. A detailed flowsheet of the ABE process is provided

  9. Acute exercise induces biphasic increase in respiratory mRNA in skeletal muscle

    International Nuclear Information System (INIS)

    Ikeda, Shin-ichi; Kizaki, Takako; Haga, Shukoh; Ohno, Hideki; Takemasa, Tohru

    2008-01-01

    Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) promotes the expression of oxidative enzymes in skeletal muscle. We hypothesized that activation of the p38 MAPK (mitogen-activated protein kinase) in response to exercise was associated with exercise-induced PGC-1α and respiratory enzymes expression and aimed to demonstrate this under the physiological level. We subjected mice to a single bout of treadmill running and found that the exercise induced a biphasic increase in the expression of respiratory enzymes mRNA. The second phase of the increase was accompanied by an increase in PGC-1α protein, but the other was not. Administration of SB203580 (SB), an inhibitor of p38 MAPK, suppressed the increase in PGC-1α expression and respiratory enzymes mRNA in both phases. These data suggest that p38 MAPK is associated with the exercise-induced expression of PGC-1α and biphasic increase in respiratory enzyme mRNAs in mouse skeletal muscle under physiological conditions

  10. Non-conventional solvents in liquid phase microextraction and aqueous biphasic systems.

    Science.gov (United States)

    An, Jiwoo; Trujillo-Rodríguez, María J; Pino, Verónica; Anderson, Jared L

    2017-06-02

    The development of rapid, convenient, and high throughput sample preparation approaches such as liquid phase microextraction techniques have been continuously developed over the last decade. More recently, significant attention has been given to the replacement of conventional organic solvents used in liquid phase microextraction techniques in order to reduce toxic waste and to improve selectivity and/or extraction efficiency. With these objectives, non-conventional solvents have been explored in liquid phase microextraction and aqueous biphasic systems. The utilized non-conventional solvents include ionic liquids, magnetic ionic liquids, and deep eutectic solvents. They have been widely used as extraction solvents or additives in various liquid phase microextraction modes including dispersive liquid-liquid microextraction, single-drop microextraction, hollow fiber-liquid phase microextraction, as well as in aqueous biphasic systems. This review provides an overview into the use of non-conventional solvents in these microextraction techniques in the past 5 years (2012-2016). Analytical applications of the techniques are also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Biphasic electrical currents stimulation promotes both proliferation and differentiation of fetal neural stem cells.

    Directory of Open Access Journals (Sweden)

    Keun-A Chang

    2011-04-01

    Full Text Available The use of non-chemical methods to differentiate stem cells has attracted researchers from multiple disciplines, including the engineering and the biomedical fields. No doubt, growth factor based methods are still the most dominant of achieving some level of proliferation and differentiation control--however, chemical based methods are still limited by the quality, source, and amount of the utilized reagents. Well-defined non-chemical methods to differentiate stem cells allow stem cell scientists to control stem cell biology by precisely administering the pre-defined parameters, whether they are structural cues, substrate stiffness, or in the form of current flow. We have developed a culture system that allows normal stem cell growth and the option of applying continuous and defined levels of electric current to alter the cell biology of growing cells. This biphasic current stimulator chip employing ITO electrodes generates both positive and negative currents in the same culture chamber without affecting surface chemistry. We found that biphasic electrical currents (BECs significantly increased the proliferation of fetal neural stem cells (NSCs. Furthermore, BECs also promoted the differentiation of fetal NSCs into neuronal cells, as assessed using immunocytochemistry. Our results clearly show that BECs promote both the proliferation and neuronal differentiation of fetal NSCs. It may apply to the development of strategies that employ NSCs in the treatment of various neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases.

  12. Is there an Optimal Shape of the Defibrillation Shock: Constant Current vs. Pulsed Biphasic Waveforms

    Directory of Open Access Journals (Sweden)

    Ivan Dotsinsky

    2013-04-01

    Full Text Available Three waveforms for transthoracic defibrillation are assessed and compared: the Pulsed Biphasic Waveform (PBW, the Rectilinear Biphasic Waveform (RBW, and the "lossless" constant current (LLCC pulses. Two indices are introduced: 1 kf = W/W0 - the ratio between the delivered energy W and the energy W0 of a rectangular pulse with the same duration and electric charge; 2 ηC = W/WC0 - the level of utilizing the initially loaded capacitor energy WC0. The envisioned comparative study shows that ηC index is favorable for both PBW and LLCC, while kf of both RBW and LLCC demonstrates advantage over the PBW in the range of small inter-electrode thoracic impedances below 80 Ω. Some design considerations are also discussed. The attractive LLCC concept needs large and heavy inductive coil to support the constant current amplitude, besides it is capable to induce strong electromagnetic influences due to the complex current control. The RBW technology controls the delivery of current through a series of internal resistors which are, however, a source of high heat losses. The PBW implements controlled duty cycle of high-frequency chopped pulses to adapt the energy delivery in respect of the patient impedance measured at the beginning of the shock. PBW technology makes use of small capacitors which allows the construction of light weight and small-size portable devices for transthoracic defibrillation.

  13. MDCT urography: experience with a bi-phasic excretory phase examination protocol

    International Nuclear Information System (INIS)

    Meindl, Thomas; Coppenrath, Eva; Degenhart, Christoph; Reiser, Maximilian F.; Mueller-Lisse, Ullrich G.; Mueller-Lisse, Ulrike L.

    2007-01-01

    The benefit of multidetector computed tomographic urography (MDCTU) for visualising early and late excretory phase (EP) upper urinary tract (UUT) opacification has been studied. UUT opacification was retrospectively evaluated in 45 bi-phasic four-row MDCTU examinations. The UUT was divided into intrarenal collecting system (IRCS), proximal, middle and distal ureter. Two independent readers rated opacification: 1, none; 2, partial; 3, complete. Numbers of segments and percentages of UUTs at each score were calculated for each EP and two EPs combined. Results of a single EP and of combined EPs were compared by Wilcoxon matched-pairs signed-ranks. IRCS and proximal ureter were at least partially opacified in each EP in >95%. The middle ureter was at least partially opacified in the early and late EP in 85% and 93%, respectively. The distal ureter was opacified in 65% (49/75) in the early EP and in 78% (59/75) in the late EP. Combining two EPs, non-opacified distal segments decreased to 9% (7/75). Significant improvement between a single EP and combining two EPs were found for the middle and distal ureter (P < 0.03). Bi-phasic MDCTU substantially improved opacification of the middle and distal ureter. IRCS and proximal ureter are reliably opacified with one EP. (orig.)

  14. Biopolymer-stabilized Pt nanoparticles colloid: a highly active and recyclable catalyst for biphasic catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yujia; Shen, Yueyue; Qiu, Yunfei; Zhang, Ting; Liao, Yang; Zhao, Shilin; Ma, Jun, E-mail: 1044208419@qq.com; Mao, Hui, E-mail: rejoice222@163.com [Sichuan Normal University, College of Chemistry and Materials Science (China)

    2016-10-15

    Noble metal nanoparticles are promising candidates to replace conventional bulk counterparts owing to their high activity and selectivity. To enable catalyst recovery, noble metal nanoparticles are often supported onto solid matrices to prepare heterogeneous catalyst. Although recycle of noble metal nanoparticles is realized by heterogenization, a loss of activity is usually encountered. In the present investigation, Pt nanoparticles with tunable particle size (1.85–2.80 nm) were facilely prepared by using polyphenols as amphiphilic stabilizers. The as-prepared Pt nanoparticles colloid solution could be used as highly active catalyst in aqueous–organic biphasic catalysis. The phenolic hydroxyls of polyphenols could constrain Pt nanoparticles in aqueous phase, and simultaneously, the aromatic scaffold of polyphenols ensured effective interactions between substrates and Pt nanoparticles. As a consequence, the obtained polyphenols-stabilized Pt nanoparticles exhibited high activity and cycling stability in biphasic hydrogenation of a series of unsaturated compounds. Compared with conventional heterogeneous Pt-C and Pt-Al{sub 2}O{sub 3} catalysts, polyphenols-stabilized Pt nanoparticles showed obvious advantage both in activity and cycling stability.

  15. Efficient One-Pot Synthesis of 5-Chloromethylfurfural (CMF from Carbohydrates in Mild Biphasic Systems

    Directory of Open Access Journals (Sweden)

    Dimitris S. Argyropoulos

    2013-07-01

    Full Text Available 5-Halomethylfurfurals can be considered as platform chemicals of high reactivity making them useful for the preparation of a variety of important compounds. In this study, a one-pot route for the conversion of carbohydrates into 5-chloromethylfurfural (CMF in a simple and efficient (HCl-H3PO4/CHCl3 biphasic system has been investigated. Monosaccharides such as D-fructose, D-glucose and sorbose, disaccharides such as sucrose and cellobiose and polysaccharides such as cellulose were successfully converted into CMF in satisfactory yields under mild conditions. Our data shows that when using D-fructose the optimum yield of CMF was about 47%. This understanding allowed us to extent our work to biomaterials, such as wood powder and wood pulps with yields of CMF obtained being comparable to those seen with some of the enumerated mono and disaccharides. Overall, the proposed (HCl-H3PO4/CHCl3 optimized biphasic system provides a simple, mild, and cost-effective means to prepare CMF from renewable resources.

  16. Biphasic pulses enhance bleomycin efficacy in a spontaneous canine genital tumor model of chemoresistance: Sticker sarcoma

    Directory of Open Access Journals (Sweden)

    Citro Gennaro

    2008-11-01

    Full Text Available Abstract Sticker's sarcoma (also known as transmissible venereal tumor is a horizontally transmitted neoplasm of the dog, that is passed with coitus. It is a locally aggressive tumor with a low tendency to metastatic spread. The most common locations are the genitals, the nose, the perianal area. Standard treatment consists with chemotherapy with vincristine, however other therapies such as, cryotherapy, immunotherapy or, in selected cases, radiation therapy, have been reported. In this article we describe the outcome of a small cohort of canine patients, with chemotherapy resistant transmissible venereal tumor (TVT, treated with bleomycin selectively driven by trains of biphasic pulses (electrochemotherapy. Three canine patients, with refractory TVT, entered the study and received two sessions of ECT under sedation. The pets had local injection of bleomycin at the concentration of 1.5 mg/ml and five minutes after the chemotherapy, trains of 8 biphasic electric pulses lasting 50 + 50 μs each, with 1 ms interpulse intervals, were delivered by means of modified caliper or, for difficult districts, through paired needle electrode. All the patients responded to the treatment and are still in remission at different times. Electrochemotherapy appears as a safe and efficacious modality for the treatment of TVT and warrants further investigations.

  17. Online Epileptic Seizure Prediction Using Wavelet-Based Bi-Phase Correlation of Electrical Signals Tomography.

    Science.gov (United States)

    Vahabi, Zahra; Amirfattahi, Rasoul; Shayegh, Farzaneh; Ghassemi, Fahimeh

    2015-09-01

    Considerable efforts have been made in order to predict seizures. Among these methods, the ones that quantify synchronization between brain areas, are the most important methods. However, to date, a practically acceptable result has not been reported. In this paper, we use a synchronization measurement method that is derived according to the ability of bi-spectrum in determining the nonlinear properties of a system. In this method, first, temporal variation of the bi-spectrum of different channels of electro cardiography (ECoG) signals are obtained via an extended wavelet-based time-frequency analysis method; then, to compare different channels, the bi-phase correlation measure is introduced. Since, in this way, the temporal variation of the amount of nonlinear coupling between brain regions, which have not been considered yet, are taken into account, results are more reliable than the conventional phase-synchronization measures. It is shown that, for 21 patients of FSPEEG database, bi-phase correlation can discriminate the pre-ictal and ictal states, with very low false positive rates (FPRs) (average: 0.078/h) and high sensitivity (100%). However, the proposed seizure predictor still cannot significantly overcome the random predictor for all patients.

  18. Isoattenuating insulinomas at biphasic contrast-enhanced CT: frequency, clinicopathologic features and perfusion characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Liang; Xue, Hua-dan; Sun, Hao; Wang, Xuan; He, Yong-lan; Jin, Zheng-yu [Peking Union Medical College Hospital, Department of Radiology, Beijing (China); Zhao, Yu-pei [Peking Union Medical College Hospital, Department of General Surgery, Beijing (China)

    2016-10-15

    We aimed to determine the frequency of isoattenuating insulinomas, to investigate their clinicopathological features and to assess their regional pancreatic perfusion characteristics. Institutional review board approval was obtained, and patient informed consent was waived. From July 2010 to June 2014, 170 patients (66 male, 104 female) with endogenous hyperinsulinemic hypoglycemia underwent biphasic contrast-enhanced CT before surgery, and 129 of those patients also received preoperative whole-pancreas CT perfusion. A total of 181 tumours were proved histopathologically after surgery. Enhancement pattern and regional pancreatic perfusion characteristics were analyzed. Clinical features, tumour size and pathological grading were investigated. The frequency of isoattenuating tumours was 24.9 %. Tumour size and WHO grading was not significantly different between isoattenuating and hyperattenuating tumours. Tumour-free regions had identical blood flow (BF) regardless of their location (p = 0.35). Isoattenuating tumour-harbouring regions had lower BF compared with hyperattenuating tumour-harbouring regions; both showed higher BF compared with tumour-free neighbourhood regions (all p < 0.01). For patients with isoattenuating tumours, the overall hospital stay was longer (p < 0.01). A substantial subset of insulinomas were isoattenuating on biphasic CT. CT perfusion showed higher BF in tumour-harbouring regions compared to tumour-free regions, providing a clue for tumour regionalization. (orig.)

  19. Biphasic effect of citral, a flavoring and scenting agent, on spatial learning and memory in rats.

    Science.gov (United States)

    Yang, Zheqiong; Xi, Jinlei; Li, Jihong; Qu, Wen

    2009-10-01

    Although some central effects of citral have been reported, cognitive effects on spatial memory have not been investigated. The evidence showed that citral can regulate the synthesis of retinoic acid (RA), which exerts a vital function in the development and maintenance of spatial memory. In this study, we applied Morris water maze to test the effect of citral on animals' spatial learning and memory. To elucidate the mechanism of this effect, we also measured the retinoic acid concentration in rats' hippocampus by high performance liquid chromatography (HPLC). Our data implied biphasic effects of citral. The low dose (0.1 mg/kg) of citral improved the spatial learning capability, and enhanced the spatial reference memory of rats, whereas the high dose (1.0 mg/kg) was like to produce the opposite effects. Meanwhile, the low dose of citral increased the hippocampal retinoic acid concentration, while the high dose decreased it. Due to the quick elimination and non-bioaccumulation in the body, effects of citral on spatial memory in this study seemed to be indirect actions. The change in hippocampal retinoic acid concentration induced by different doses of citral might be responsible for the biphasic effect of citral on spatial learning and memory.

  20. Solar Imagery - Chromosphere - Calcium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about 500...

  1. Antenatal calcium intake in Malaysia.

    Science.gov (United States)

    Mahdy, Zaleha Abdullah; Basri, Hashimah; Md Isa, Zaleha; Ahmad, Shuhaila; Shamsuddin, Khadijah; Mohd Amin, Rahmah

    2014-04-01

    To determine the adequacy of antenatal calcium intake in Malaysia, and the influencing factors. A cross-sectional study was conducted among postnatal women who delivered in two tertiary hospitals. Data were collected from antenatal cards, hospital documents and diet recall on daily milk and calcium intake during pregnancy. SPSS version 19.0 was used for statistical analyses. A total of 150 women were studied. The total daily calcium intake was 834 ± 43 mg (mean ± standard error of the mean), but the calcium intake distribution curve was skewed to the right with a median intake of 725 mg daily. When calcium intake from milk and calcium supplements was excluded, the daily dietary calcium intake was only 478 ± 25 mg. Even with inclusion of milk and calcium supplements, more than a third (n=55 or 36.7%) of the women consumed less than 600 mg calcium in their daily diet. The adequacy of daily calcium intake was not influenced by maternal age, ethnicity, income or maternal job or educational status as well as parity. The daily dietary calcium intake of the Malaysian antenatal population is far from adequate without the addition of calcium supplements and milk. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

  2. The Plasma Membrane Calcium Pump

    Science.gov (United States)

    Rasmussen, H.

    1983-01-01

    Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

  3. A prospective, randomised and blinded comparison of first shock success of monophasic and biphasic waveforms in out-of-hospital cardiac arrest

    NARCIS (Netherlands)

    van Alem, Anouk P.; Chapman, Fred W.; Lank, Paula; Hart, Augustinus A. M.; Koster, Rudolph W.

    2003-01-01

    Background: Evidence suggests that biphasic waveforms are more effective than monophasic waveforms for defibrillation in out-of-hospital cardiac arrest (OHCA), yet their performance has only been compared in un-blinded studies. Methods and results: We compared the success of biphasic truncated

  4. Calcium Domains around Single and Clustered IP3 Receptors and Their Modulation by Buffers

    Science.gov (United States)

    Rüdiger, S.; Nagaiah, Ch.; Warnecke, G.; Shuai, J.W.

    2010-01-01

    Abstract We study Ca2+ release through single and clustered IP3 receptor channels on the ER membrane under presence of buffer proteins. Our computational scheme couples reaction-diffusion equations and a Markovian channel model and allows our investigating the effects of buffer proteins on local calcium concentrations and channel gating. We find transient and stationary elevations of calcium concentrations around active channels and show how they determine release amplitude. Transient calcium domains occur after closing of isolated channels and constitute an important part of the channel's feedback. They cause repeated openings (bursts) and mediate increased release due to Ca2+ buffering by immobile proteins. Stationary domains occur during prolonged activity of clustered channels, where the spatial proximity of IP3Rs produces a distinct [Ca2+] scale (0.5–10 μM), which is smaller than channel pore concentrations (>100 μM) but larger than transient levels. While immobile buffer affects transient levels only, mobile buffers in general reduce both transient and stationary domains, giving rise to Ca2+ evacuation and biphasic modulation of release amplitude. Our findings explain recent experiments in oocytes and provide a general framework for the understanding of calcium signals. PMID:20655827

  5. Calcium supplementation decreases BCP-induced inflammatory processes in blood cells through the NLRP3 inflammasome down-regulation.

    Science.gov (United States)

    Lagadec, Patricia; Balaguer, Thierry; Boukhechba, Florian; Michel, Grégory; Bouvet-Gerbettaz, Sébastien; Bouler, Jean-Michel; Scimeca, Jean-Claude; Rochet, Nathalie

    2017-07-15

    Interaction of host blood with biomaterials is the first event occurring after implantation in a bone defect. This study aimed at investigating the cellular and molecular consequences arising at the interface between whole blood and biphasic calcium phosphate (BCP) particles. We observed that, due to calcium capture, BCP inhibited blood coagulation, and that this inhibition was reversed by calcium supplementation. Therefore, we studied the impact of calcium supplementation on BCP effects on blood cells. Comparative analysis of BCP and calcium supplemented-BCP (BCP/Ca) effects on blood cells showed that BCP as well as BCP/Ca induced monocyte proliferation, as well as a weak but significant hemolysis. Our data showed for the first time that calcium supplementation of BCP microparticles had anti-inflammatory properties compared to BCP alone that induced an inflammatory response in blood cells. Our results strongly suggest that the anti-inflammatory property of calcium supplemented-BCP results from its down-modulating effect on P2X7R gene expression and its capacity to inhibit ATP/P2X7R interactions, decreasing the NLRP3 inflammasome activation. Considering that monocytes have a vast regenerative potential, and since the excessive inflammation often observed after bone substitutes implantation limits their performance, our results might have great implications in terms of understanding the mechanisms leading to an efficient bone reconstruction. Although scaffolds and biomaterials unavoidably come into direct contact with blood during bone defect filling, whole blood-biomaterials interactions have been poorly explored. By studying in 3D the interactions between biphasic calcium phosphate (BCP) in microparticulate form and blood, we showed for the first time that calcium supplementation of BCP microparticles (BCP/Ca) has anti-inflammatory properties compared to BCP-induced inflammation in whole blood cells and provided information related to the molecular mechanisms

  6. Synthesis of calcium phosphates and porous hydroxyapatite beads prepared by emulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, B.-H. [Faculty of Biotechnology, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Chen, K.-I [Department of Electronics Engineering and Computer Science, Tung-Fang Institute of Technology, 100 Dungfang Road, Hunei, Kaohsiung, Taiwan (China); Ho, M.-L. [Department of Physiology, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Chen, H.-N. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Chen, W.-C. [Faculty of Dentistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Wang, C.-K. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China)], E-mail: ckwang@kmu.edu.tw

    2009-01-15

    Raw calcium phosphates were synthesized via a chemical reaction between 0.5 M orthophosphoric acid and 0.5 M calcium hydroxide. Hydroxyapatite (HAp), {beta}-tricalcium phosphate ({beta}-TCP) or biphase calcium phosphate (BCP) comprising HAp and {beta}-TCP were obtained by changing pH value, Ca/P ratio, and the addition of glycerol. The as-synthesized and heat-treated powders were analyzed by X-ray diffraction (XRD) and Fourier transformation infrared spectrometry (FTIR). Thermal stability of the pure apatite phase was obtained to be 1300 deg. C, while synthesis was done at the pH value of 10.0 with a Ca/P ratio of 2.0 and a temperature of 37 deg. C. Besides, the {beta}-TCP phase (with higher purity) was achieved at 800 deg. C, whose synthesis was done at pH 6.4 with a Ca/P ratio of 1.5 and a temperature of 37 deg. C. Therefore, the biphase bioceramics comprising of HAp and {beta}-TCP could be obtained, since it was manipulated suitably. The HAp raw material was subjected to a simple emulsion method for the preparation of porous beads. They should have the advantage of exhibiting higher adsorptive ability and osteoconductivity in comparison with the sintered dense apatite. Additionally, the porous beads of apatite were demonstrated to be non-toxic to cells, and should be suitable for the use as a scaffold of cultured bone and bone graft material, as well as for drug delivery systems.

  7. Voltage-Gated Calcium Channels

    Science.gov (United States)

    Zamponi, Gerald Werner

    Voltage Gated Calcium Channels is the first comprehensive book in the calcium channel field, encompassing over thirty years of progress towards our understanding of calcium channel structure, function, regulation, physiology, pharmacology, and genetics. This book balances contributions from many of the leading authorities in the calcium channel field with fresh perspectives from risings stars in the area, taking into account the most recent literature and concepts. This is the only all-encompassing calcium channel book currently available, and is an essential resource for academic researchers at all levels in the areas neuroscience, biophysics, and cardiovascular sciences, as well as to researchers in the drug discovery area.

  8. Does the calcification of adamantinomatous craniopharyngioma resemble the calcium deposition of osteogenesis/odontogenesis?

    Science.gov (United States)

    Song-Tao, Qi; Xiao-Rong, Yan; Jun, Pan; Yong-Jian, Deng; Jin, Liang; Guang-Long, Huang; Yun-Tao, Lu; Jian, Ruan; Xiang-Zhao, Li; Jia-Ming, Xu

    2014-02-01

    Calcification in adamantinomatous craniopharyngioma (ACP) is troublesome for surgical intervention. The aim of this study was to examine the osteogenic proteins that play important roles in the calcium deposition of the odontogenic/osteogenic tissues in craniopharyngioma. Craniopharyngiomas (n = 89) were investigated for the presence and expression pattern of the osteoinductive/odontoinductive factor bone morphogenetic protein-2 (Bmp2) and two osteoblastic differentiation makers, Runt-related transcription factor-2 (Runx2) and Osterix, using immunohistochemistry and Western blotting. Our results showed that Bmp2, Runx2 and Osterix levels increased in cases with high calcification and correlated positively with the degree of calcification in ACP, whereas they showed little or no expression in squamous papillary craniopharyngioma. In ACP, Bmp2 was expressed primarily in the stellate reticulum and whorl-like array cells; Runx2 and Osterix tended to be expressed in calcification-related epithelia, including whorl-like array cells and epithelia in/around wet keratin and calcification lesions. Our study indicated, for the first time, that osteogenic factor Bmp2 may play an important role in the calcification of ACP via autocrine or paracrine mechanisms. Given the presence of osteogenic markers (Runx2 and Osterix), craniopharyngioma cells could differentiate into an osteoblast-like lineage, and the process of craniopharyngioma calcification resembles that which occurs in osteogenesis/odontogenesis. © 2014 John Wiley & Sons Ltd.

  9. Comparison of low-energy versus high-energy biphasic defibrillation shocks following prolonged ventricular fibrillation.

    Science.gov (United States)

    Walcott, Gregory P; Melnick, Sharon B; Killingsworth, Cheryl R; Ideker, Raymond E

    2010-01-01

    Since the initial development of the defibrillator, there has been concern that, while delivery of a large electric shock would stop fibrillation, it would also cause damage to the heart. This concern has been raised again with the development of the biphasic defibrillator. To compare defibrillation efficacy, postshock cardiac function, and troponin I levels following 150-J and 360-J shocks. Nineteen swine were anesthetized with isoflurane and instrumented with pressure catheters in the left ventricle, aorta, and right atrium. The animals were fibrillated for 6 minutes, followed by defibrillation with either low-energy (n = 8) or high-energy (n = 11) shocks. After defibrillation, chest compressions were initiated and continued until return of spontaneous circulation (ROSC). Epinephrine, 0.01 mg/kg every 3 minutes, was given for arterial blood pressure < 50 mmHg. Hemodynamic parameters were recorded for four hours. Transthoracic echocardiography was performed and troponin I levels were measured at baseline and four hours following ventricular fibrillation (VF). Survival rates at four hours were not different between the two groups (low-energy, 5 of 8; high-energy, 7 of 11). Results for arterial blood pressure, positive dP/dt (first derivative of pressure measured over time, a measure of left ventricular contractility), and negative dP/dt at the time of lowest arterial blood pressure (ABP) following ROSC were not different between the two groups (p = not significant [NS]), but were lower than at baseline. All hemodynamic measures returned to baseline by four hours. Ejection fractions, stroke volumes, and cardiac outputs were not different between the two groups at four hours. Troponin I levels at four hours were not different between the two groups (12 +/- 11 ng/mL versus 21 +/- 26 ng/mL, p = NS) but were higher at four hours than at baseline (19 +/- 19 ng/mL versus 0.8 +/- 0.5 ng/mL, p < 0.05, groups combined). Biphasic 360-J shocks do not cause more cardiac damage

  10. Temperature dependence of microwave absorption phenomena in single and biphase soft magnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    El Kammouni, Rhimou, E-mail: elkammounirhimou@gmail.com [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Vázquez, Manuel [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Lezama, Luis [Depto. Química Inorgánica, Universidad País Vasco, UPV/EHU, Bilbao (Spain); Kurlyandskaya, Galina [Depto. Electricidad y Electrónica, Universidad País Vasco, UPV/EHU, Bilbao (Spain); Dept. Magnetism and Magnetic Nanomaterials, Ural Federal University, Ekaterinburg (Russian Federation); Kraus, Ludek [Institute of Physics, Academy of Sciences of the Czech Republic, Prague (Czech Republic)

    2014-11-15

    The microwave absorption phenomena of single and biphase magnetic microwires with soft magnetic behavior have been investigated as a function of DC applied magnetic field using two alternative techniques: (i) absorption measurements in the temperature range of 4–300 K using a spectrometer operating at X-band frequency, at 9.5 GHz, and (ii) room-temperature, RT, ferromagnetic resonance measurements in a network analyzer in the frequency range up to 20 GHz. Complementary low-frequency magnetic characterization was performed in a Vibrating Sample Magnetometer. Studies have been performed for 8 μm diameter small-magnetostriction amorphous CoFeSiB single-phase microwire, coated by micrometric Pyrex layer, and after electroplating an external shell, 2 µm or 4 µm thick, of FeNi alloys. For single phase CoFeSiB microwire, a single absorption is observed, whose DC field dependence of resonance frequency at RT fits to a Kittel-law behavior for in-plane magnetized thin film. The temperature dependence behavior shows a monotonic increase in the resonance field, H{sub r}, with temperature. A parallel reduction of the circular anisotropy field, H{sub K}, is deduced from the temperature dependence of hysteresis loops. For biphase, CoFeSiB/FeNi, microwires, the absorption phenomena at RT also follow the Kittel condition. The observed opposite evolution with temperature of resonance field, H{sub r}, in 2 and 4 µm thick FeNi samples is interpreted considering the opposite sign of magnetostriction of the respective FeNi layers. The stress-induced magnetic anisotropy field, H{sub K}, in the FeNi shell is deduced to change sign at around 130 K. - Highlights: • A single absorption phenomenon is observed for single phase CoFeSiB. • The T dependence of the microwave behavior shows a monotonic increase of H{sub r} with T. • The absorption at RT follows the Kittel condition for biphase CoFe/FeNi microwires. • The T dependence of resonant field of CoFe/FeNi is interpreted to be

  11. Selective formation of biphasic thin films of metal–organic frameworks by potential-controlled cathodic electrodeposition

    OpenAIRE

    Li, Minyuan Miller; Dinca, Mircea

    2013-01-01

    Cathodic electrodeposition lends itself to the formation of biphasic metal–organic framework thin films at room temperature from single deposition baths using potential bias as the main user input. Depending on the applied potential, we selectively deposit two different phases as either bulk mixtures or bilayer films.

  12. Induction of bone formation by smart biphasic hydroxyapatite tricalcium phosphate biomimetic matrices in the non-human primate Papio ursinus

    CSIR Research Space (South Africa)

    Ripamonti, U

    2008-01-01

    Full Text Available Long-term studies in the non-human primate Chacma baboon Papio ursinus were set to investigate the induction of bone formation by biphasic hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) biomimetic matrices. HA/β-TCP biomimetic matrices in a pre...

  13. INVESTIGATION OF AQUEOUS BIPHASIC SYSTEMS FOR THE SEPARATIONS OF LIGNINS FROM CELLULOSE IN THE PAPER PULPING PROCESS. (R826732)

    Science.gov (United States)

    In efforts to apply a polymer-based aqueous biphasic system (ABS) extraction to the paper pulping process, the study of the distribution of various lignin and cellulosic fractions in ABS and the effects of temperature on system composition and solute partitioning have been inv...

  14. Chiral separation of α-cyclohexylmandelic acid enantiomers by high-speed counter-current chromatography with biphasic recognition

    Science.gov (United States)

    Tong, Shengqiang

    2010-01-01

    This work concentrates on a novel chiral separation technology named biphasic recognition applied to resolution of α-cyclohexylmandelic acid enantiomers by high-speed counter-current chromatography (HSCCC). The biphasic chiral recognition HSCCC was performed by adding lipophilic (−)-2-ethylhexyl tartrate in the organic stationary phase and hydrophilic hydroxypropyl-β-cyclodextrin in the aqueous mobile phase, which preferentially recognized the (−)-enantiomer and (+)-enantiomer, respectively. The two-phase solvent system composed of n-hexane-methyl tert-butyl ether-water (9:1:10, v/v/v) with the above chiral selectors was selected according to the partition coefficient and separation factor of the target enantiomers. Various parameters involved in the chiral separation were investigated, namely the types of the chiral selector (CS); the concentration of each chiral selector; pH of the mobile phase; and the separation temperature. The mechanism involved in this biphasic recognition chiral separation by HSCCC was discussed. Langmuirian isotherm was employed to estimate the loading limits for each chiral selector. The overall experimental results show that the HSCCC separation of enantiomer based on biphasic recognition is much more efficient than the traditional monophasic recognition chiral separation, since it utilizes the cooperation of both lipophilic and hydrophilic chiral selectors. PMID:20303497

  15. Efficient asymmetric hydrolysis of styrene oxide catalyzed by Mung bean epoxide hydrolases in ionic liquid-based biphasic systems.

    Science.gov (United States)

    Chen, Wen-Jing; Lou, Wen-Yong; Zong, Min-Hua

    2012-07-01

    The asymmetric hydrolysis of styrene oxide to (R)-1-phenyl-1,2-ethanediol using Mung bean epoxide hydrolases was, for the first time, successfully conducted in an ionic liquid (IL)-containing biphasic system. Compared to aqueous monophasic system, IL-based biphasic systems could not only dissolve the substrate, but also effectively inhibit the non-enzymatic hydrolysis, and therefore markedly improve the reaction efficiency. Of all the tested ILs, the best results were observed in the biphasic system containing C(4)MIM·PF(6), which exhibited good biocompatibility with the enzyme and was an excellent solvent for the substrate. In the C(4)MIM·PF(6)/buffer biphasic system, it was found that the optimal volume ratio of IL to buffer, reaction temperature, buffer pH and substrate concentration were 1/6, 35°C, 6.5 and 100 mM, respectively, under which the initial reaction rate, the yield and the product e.e. were 18.4 mM/h, 49.4% and 97.0%. The biocatalytic process was shown to be feasible on a 500-mL preparative scale. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Calcium, essential for health

    Science.gov (United States)

    Martínez de Victoria, Emilio

    2016-07-12

    Calcium (Ca) is the most abundant mineral element in our body. It accounts for about 2% of body weight. The functions of calcium are: a) functions skeletal and b) regulatory functions. Bone consists of a protein matrix that mineralizes mainly with calcium (the most abundant), phosphate and magnesium, for it is essential an adequate dietary intake of Ca, phosphorus and vitamin D. The ionic Ca (Ca2+) is essential to maintain and / or perform different specialized functions of, virtually, all body cells cellular. Because of its important functions Ca2+ must be closely regulated, keeping plasma concentrations within narrow ranges. For this reason there is an accurate response against hypocalcemia or hypercalcemia in which the parathormone, calcitriol, calcitonin and vitamin K are involved. Ca intakes in the Spanish population are low in a significant percentage of the older adult’s population, especially in women. The main source of Ca in the diet is milk and milk derivatives. Green leafy vegetables, fruits and legumes can be important sources of Ca in a Mediterranean dietary pattern. The bioavailability of dietary Ca depends on physiological and dietary factors. Physiological include age, physiological status (gestation and lactation) Ca and vitamin D status and disease. Several studies relate Ca intake in the diet and various diseases, such as osteoporosis, cancer, cardiovascular disease and obesity.

  17. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James

    2016-01-01

    This book discusses the ways in which mathematical, computational, and modelling methods can be used to help understand the dynamics of intracellular calcium. The concentration of free intracellular calcium is vital for controlling a wide range of cellular processes, and is thus of great physiological importance. However, because of the complex ways in which the calcium concentration varies, it is also of great mathematical interest.This book presents the general modelling theory as well as a large number of specific case examples, to show how mathematical modelling can interact with experimental approaches, in an interdisciplinary and multifaceted approach to the study of an important physiological control mechanism. Geneviève Dupont is FNRS Research Director at the Unit of Theoretical Chronobiology of the Université Libre de Bruxelles;Martin Falcke is head of the Mathematical Cell Physiology group at the Max Delbrück Center for Molecular Medicine, Berlin;Vivien Kirk is an Associate Professor in the Depar...

  18. A Simplified Whole-Organ CT Perfusion Technique with Biphasic Acquisition: Preliminary Investigation of Accuracy and Protocol Feasibility in Kidneys.

    Science.gov (United States)

    Yuan, XiaoDong; Zhang, Jing; Quan, ChangBin; Tian, Yuan; Li, Hong; Ao, GuoKun

    2016-04-01

    To determine the feasibility and accuracy of a protocol for calculating whole-organ renal perfusion (renal blood flow [RBF]) and regional perfusion on the basis of biphasic computed tomography (CT), with concurrent dynamic contrast material-enhanced (DCE) CT perfusion serving as the reference standard. This prospective study was approved by the institutional review board, and written informed consent was obtained from all patients. Biphasic CT of the kidneys, including precontrast and arterial phase imaging, was integrated with a first-pass dynamic volume CT protocol and performed and analyzed in 23 patients suspected of having renal artery stenosis. The perfusion value derived from biphasic CT was calculated as CT number enhancement divided by the area under the arterial input function and compared with the DCE CT perfusion data by using the paired t test, correlation analysis, and Bland-Altman plots. Correlation analysis was made between the RBF and the extent of renal artery stenosis. All postprocessing was independently performed by two observers and then averaged as the final result. Mean ± standard deviation biphasic and DCE CT perfusion data for RBF were 425.62 mL/min ± 124.74 and 419.81 mL/min ± 121.13, respectively (P = .53), and for regional perfusion they were 271.15 mL/min per 100 mL ± 82.21 and 266.33 mL/min per 100 mL ± 74.40, respectively (P = .31). Good correlation and agreement were shown between biphasic and DCE CT perfusion for RBF (r = 0.93; ±10% variation from mean perfusion data [P < .001]) and for regional perfusion (r = 0.90; ±13% variation from mean perfusion data [P < .001]). The extent of renal artery stenosis was negatively correlated with RBF with biphasic CT perfusion (r = -0.81, P = .012). Biphasic CT perfusion is clinically feasible and provides perfusion data comparable to DCE CT perfusion data at both global and regional levels in the kidney. Online supplemental material is available for this article.

  19. A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

    Directory of Open Access Journals (Sweden)

    Andrew Bogdan

    2009-04-01

    Full Text Available We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leaving the organic product separate from the aqueous by-products. Furthermore, the microreactor oxidized a wide range of alcohols and remained active in excess of 100 trials without showing any loss of catalytic activity.

  20. Obtaining of ceramics biphasic dense and porous; Obtencao de ceramicas bifasicas densas e porosas

    Energy Technology Data Exchange (ETDEWEB)

    Pallone, E.M.J.A.; Rigo, E.C.S., E-mail: eliria@usp.b [Universidade de Sao Paulo (FZEA/USP), Pirassununga, SP (Brazil). Dept. de Ciencias Basicas; Silva, K.L. [Universidade Estadual de Campinas (FEM/UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica; Rezende, M.E. [Universidade Sao Francisco, Itatiba, SP (Brazil); Fraga, A.F. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Marques, R.F.C. [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil)

    2010-07-01

    Among the bioceramic hydroxyapatite (HAP) and beta-tricalcium phosphate (beta-TCP) are materials commonly used in biomedical field. Their combined properties result in a material with absorbable and at the same time with bioactive surface. Called biphasic ceramics such materials respond more quickly when exposed to physiological environment. In this work, powders of HAP/beta-TCP were obtained by chemical precipitation. After obtaining the post-phase was added at a ratio of 0, 15% and 30w% aqueous solutions of corn starch in order to obtain porous bodies. After mixing the resulting solutions were dried, resigned in tablet form and sintered at 1300 deg C. The initial powder was characterized by X-ray diffraction with Rietveld refinement to quantify the phases present. Bodies-of-evidence has been characterized by calculating the bulk density, X-ray diffraction (XRD), scanning electron microscopy and diametral compression. (author)

  1. Pickering interfacial catalysis for biphasic systems: from emulsion design to green reactions.

    Science.gov (United States)

    Pera-Titus, Marc; Leclercq, Loïc; Clacens, Jean-Marc; De Campo, Floryan; Nardello-Rataj, Véronique

    2015-02-09

    Pickering emulsions are surfactant-free dispersions of two immiscible fluids that are kinetically stabilized by colloidal particles. For ecological reasons, these systems have undergone a resurgence of interest to mitigate the use of synthetic surfactants and solvents. Moreover, the use of colloidal particles as stabilizers provides emulsions with original properties compared to surfactant-stabilized emulsions, microemulsions, and micellar systems. Despite these specific advantages, the application of Pickering emulsions to catalysis has been rarely explored. This Minireview describes very recent examples of hybrid and composite amphiphilic materials for the design of interfacial catalysts in Pickering emulsions with special emphasis on their assets and challenges for industrially relevant biphasic reactions in fine chemistry, biofuel upgrading, and depollution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Spindle-cell squamous carcinoma of the esophagus: a tumor with biphasic morphology

    International Nuclear Information System (INIS)

    Agha, F.P.; Keren, D.F.

    1985-01-01

    Spindle-cell squamous carcinoma of the esophagus is a rare malignant tumor. It is characterized by a large bulky mass in the middle third of the esophagus with a lobulated surface and local expansion of the esophagus. This lesion may be pedunculated and cause relatively little obstruction despite its bulk. The current view, based on ultrastructure and immunohistochemical evidence, has confirmed that the sarcomatous component of the squamous cell carcinoma originates from mesenchymal metaplasia of squamous cells. On the basis of this evidence and clinical behavior, it seems appropriate to consider carcinosarcoma and pseudosarcoma as equivalents and as variants of squamous cell carcinoma. Four patients with spindle-cell squamous carcinoma, an unusual subset of squamous carcinoma, are described, and the salient radiographic and pathologic features of this disorder's distinctive biphasic morphology are discussed

  3. Determination of percent calcium carbonate in calcium chromate

    International Nuclear Information System (INIS)

    Middleton, H.W.

    1979-01-01

    The precision, accuracy and reliability of the macro-combustion method is superior to the Knorr alkalimetric method, and it is faster. It also significantly reduces the calcium chromate waste accrual problem. The macro-combustion method has been adopted as the official method for determination of percent calcium carbonate in thermal battery grade anhydrous calcium chromate and percent calcium carbonate in quicklime used in the production of calcium chromate. The apparatus and procedure can be used to measure the percent carbonate in inorganic materials other than calcium chromate. With simple modifications in the basic apparatus and procedure, the percent carbon and hydrogen can be measured in many organic material, including polymers and polymeric formulations. 5 figures, 5 tables

  4. Characterization of liver metastases: the efficacy of biphasic magnetic resonance imaging with ferucarbotran-enhancement

    International Nuclear Information System (INIS)

    Hong, H.S.; Byun, J.H.; Won, H.J.; Kim, K.W.; Lee, S.S.; Lee, M.G.; Yun, S.C.

    2010-01-01

    Aim: To retrospectively evaluate the efficacy of biphasic magnetic resonance imaging (MRI) of the liver with ferucarbotran-enhancement for the characterization of hepatic metastases. Materials and methods: Thirty-six patients underwent MRI of the liver with separate acquisition of double-contrast enhancement consisting of gadolinium and ferucarbotran. A total of 106 focal hepatic lesions (51 metastases, 31 cysts, 23 haemangiomas, and one eosinophilic abscess) were included. Two sets of MRI were analysed: (1) ferucarbotran set: ferucarbotran-enhanced T1-weighted (T1W) dynamic imaging combined with ferucarbotran-enhanced T2*-weighted (T2*W) delayed imaging and (2) double set: gadolinium-enhanced T1W dynamic imaging combined with ferucarbotran-enhanced T2*W delayed imaging. The diagnostic accuracy of the two sets was evaluated using alternative free-response receiver operating characteristic curve analysis. Sensitivity and specificity were compared using the McNemar test. The enhancement pattern of focal hepatic lesions was analysed on gadolinium and ferucarbotran-enhanced T1W dynamic imaging. Results: There was no significant difference in the accuracy of characterizing hepatic metastases between the two sets. Sensitivity and specificity were not significantly different between the sets (p > 0.05). Peripheral rim enhancement was exhibited in 57% of metastatic lesions on ferucarbotran-enhanced T1W dynamic imaging. The majority (96%) of hepatic haemangiomas demonstrated typical peripheral nodular enhancement with progression on ferucarbotran-enhanced T1W dynamic imaging and were easily differentiated from metastases. Conclusion: Biphasic MRI of the liver with ferucarbotran-enhancement alone provided comparable diagnostic efficacy to double-contrast MRI for the characterization of hepatic metastases.

  5. Progranulin haploinsufficiency causes biphasic social dominance abnormalities in the tube test.

    Science.gov (United States)

    Arrant, A E; Filiano, A J; Warmus, B A; Hall, A M; Roberson, E D

    2016-07-01

    Loss-of-function mutations in progranulin (GRN) are a major autosomal dominant cause of frontotemporal dementia (FTD), a neurodegenerative disorder in which social behavior is disrupted. Progranulin-insufficient mice, both Grn(+/-) and Grn(-/-) , are used as models of FTD due to GRN mutations, with Grn(+/-) mice mimicking the progranulin haploinsufficiency of FTD patients with GRN mutations. Grn(+/-) mice have increased social dominance in the tube test at 6 months of age, although this phenotype has not been reported in Grn(-/-) mice. In this study, we investigated how the tube test phenotype of progranulin-insufficient mice changes with age, determined its robustness under several testing conditions, and explored the associated cellular mechanisms. We observed biphasic social dominance abnormalities in Grn(+/-) mice: at 6-8 months, Grn(+/-) mice were more dominant than wild-type littermates, while after 9 months of age, Grn(+/-) mice were less dominant. In contrast, Grn(-/-) mice did not exhibit abnormal social dominance, suggesting that progranulin haploinsufficiency has distinct effects from complete progranulin deficiency. The biphasic tube test phenotype of Grn(+/-) mice was associated with abnormal cellular signaling and neuronal morphology in the amygdala and prefrontal cortex. At 6-9 months, Grn(+/-) mice exhibited increased mTORC2/Akt signaling in the amygdala and enhanced dendritic arbors in the basomedial amygdala, and at 9-16 months Grn(+/-) mice exhibited diminished basal dendritic arbors in the prelimbic cortex. These data show a progressive change in tube test dominance in Grn(+/-) mice and highlight potential underlying mechanisms by which progranulin insufficiency may disrupt social behavior. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  6. Regulation of the demographic structure in isomorphic biphasic life cycles at the spatial fine scale.

    Directory of Open Access Journals (Sweden)

    Vasco Manuel Nobre de Carvalho da Silva Vieira

    Full Text Available Isomorphic biphasic algal life cycles often occur in the environment at ploidy abundance ratios (Haploid:Diploid different from 1. Its spatial variability occurs within populations related to intertidal height and hydrodynamic stress, possibly reflecting the niche partitioning driven by their diverging adaptation to the environment argued necessary for their prevalence (evolutionary stability. Demographic models based in matrix algebra were developed to investigate which vital rates may efficiently generate an H:D variability at a fine spatial resolution. It was also taken into account time variation and type of life strategy. Ploidy dissimilarities in fecundity rates set an H:D spatial structure miss-fitting the ploidy fitness ratio. The same happened with ploidy dissimilarities in ramet growth whenever reproductive output dominated the population demography. Only through ploidy dissimilarities in looping rates (stasis, breakage and clonal growth did the life cycle respond to a spatially heterogeneous environment efficiently creating a niche partition. Marginal locations were more sensitive than central locations. Related results have been obtained experimentally and numerically for widely different life cycles from the plant and animal kingdoms. Spore dispersal smoothed the effects of ploidy dissimilarities in fertility and enhanced the effects of ploidy dissimilarities looping rates. Ploidy dissimilarities in spore dispersal could also create the necessary niche partition, both over the space and time dimensions, even in spatial homogeneous environments and without the need for conditional differentiation of the ramets. Fine scale spatial variability may be the key for the prevalence of isomorphic biphasic life cycles, which has been neglected so far.

  7. Use of Respiratory Support in the Biphase Ventilation Airway Mode in the Newborn

    Directory of Open Access Journals (Sweden)

    S. N. Koval

    2006-01-01

    Full Text Available Biphasic positive airway pressure (BIPAP (also known as DuoPAP, BiLevel, BiVent, PCV+, SPAP is a mode of ventilation with cycling variations between two continuous positive airway pressure levels. It is a mixture of pressure controlled ventilation and spontaneous breathing, which is unrestricted in each phase of the respiratory cycle. The volume displacement caused by the difference between Phigh and Plow airway pressure level. The phase time ratio (PTR — the BIPAP frequency is calculated as the ratio between the durations of the two pressure phases, a PTR greater than 1:1 is called APRV (airway pressure release ventilation. In patients with ARDS maintained spontaneous breathing with BIPAP resulted in lower venous admixture and better arterial blood oxygenation as compared with A/C. Only a few studies with BIPAP have been performed in newborn and infants until now. We studied the use of BIPAP in newborn (body mass > 3kg and randomised 40 patients with respiratory failure for ventilation with BIPAP (n=20 or conventional mechanical ventilatory support (assist-control A/C — synchronised intermittent mandatory ventilation (SIMV (n=20. The Pediatric Risk of Mortality score (PRISM were collected for each patient. Fentanyl, diazepam, GABA were used as sedatives and adjusted in accordance with the Cook scale. We compared ventilatory parameters, information pertaining to pulmonary function and oxygen delivery, cardiac output, additional descriptors of organ system functions, duration and complications of ventilation and number and dosages of sedatives administered. All the patients that we intended to ventilate with BIPAP were successfully ventilated, we can conclude that biphasic ventilatory support suitable mode of ventilation for newborn with a decreased need of analgetics and sedatives than A/C. Finally, BIPAP is an a effective safe, and easy to use for personal mode of mechanical ventilatory support in newborn. 

  8. Influence of microstructure on low cycle fatigue in some single phase and biphasic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Stolarz, J. [Ecole Nationale Superieure des Mines, Centre SMS, URA CNRS 1884, Saint-Etienne (France)

    2004-07-01

    This overview deals with the effects of microstructural parameters in different single phase and biphasic stainless steels on short crack behaviour and on fatigue life in the low cycle regime. The effect of the grain size is investigated in a single phase austenitic stainless steel. Under plastic strain control, the fatigue life increases when the grain size decreases. The results are discussed by analysing the distributions of crack depths as a function of the grain size. The second type of material is a metastable austenitic steel which partially transforms into martensite during LCF at temperatures between -50 C and +120 C. The grain size of the initially single phase austenitic microstructure has a combined influence on the volume fraction of martensite produced during fatigue and on the fatigue life. In this case, the grain size effect is still considerable but totally indirect because all fatigue cracks grow exclusively in the martensite. The cyclic behaviour analysis in biphasic alloys in which two phases undergo plastic deformation during LCF is considerably more complex because the conventional concept of microstructural barriers cannot be applied. The possible damage patterns in a pair of grains with different mechanical properties are discussed on the example of a solution treated and aged superduplex austenitic-ferritic stainless steel (SDSS). The hardening of one phase (ferrite) through ageing at 475 C changes the cyclic behaviour of the initial ''quasi single phase'' microstructure. Consequently, the fatigue life under plastic strain control decreases compared with the solution treated SDSS. The discussion is focussed on LCF damage mechanisms at the microstructure size scale with a particular accent put on the propagation of short cracks in the bulk. All the microstructures exhibit some common features with respect to the behaviour of short cracks. In particular a strong effect of microstructural barriers in the bulk and the

  9. Assessing composition and structure of soft biphasic media from Kelvin-Voigt fractional derivative model parameters

    Science.gov (United States)

    Zhang, Hongmei; Wang, Yue; Fatemi, Mostafa; Insana, Michael F.

    2017-03-01

    Kelvin-Voigt fractional derivative (KVFD) model parameters have been used to describe viscoelastic properties of soft tissues. However, translating model parameters into a concise set of intrinsic mechanical properties related to tissue composition and structure remains challenging. This paper begins by exploring these relationships using a biphasic emulsion materials with known composition. Mechanical properties are measured by analyzing data from two indentation techniques—ramp-stress relaxation and load-unload hysteresis tests. Material composition is predictably correlated with viscoelastic model parameters. Model parameters estimated from the tests reveal that elastic modulus E 0 closely approximates the shear modulus for pure gelatin. Fractional-order parameter α and time constant τ vary monotonically with the volume fraction of the material’s fluid component. α characterizes medium fluidity and the rate of energy dissipation, and τ is a viscous time constant. Numerical simulations suggest that the viscous coefficient η is proportional to the energy lost during quasi-static force-displacement cycles, E A . The slope of E A versus η is determined by α and the applied indentation ramp time T r. Experimental measurements from phantom and ex vivo liver data show close agreement with theoretical predictions of the η -{{E}A} relation. The relative error is less than 20% for emulsions 22% for liver. We find that KVFD model parameters form a concise features space for biphasic medium characterization that described time-varying mechanical properties. The experimental work was carried out at the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Methodological development, including numerical simulation and all data analysis, were carried out at the school of Life Science and Technology, Xi’an JiaoTong University, 710049, China.

  10. Seizure characteristics of epilepsy in childhood after acute encephalopathy with biphasic seizures and late reduced diffusion.

    Science.gov (United States)

    Ito, Yuji; Natsume, Jun; Kidokoro, Hiroyuki; Ishihara, Naoko; Azuma, Yoshiteru; Tsuji, Takeshi; Okumura, Akihisa; Kubota, Tetsuo; Ando, Naoki; Saitoh, Shinji; Miura, Kiyokuni; Negoro, Tamiko; Watanabe, Kazuyoshi; Kojima, Seiji

    2015-08-01

    The aim of this study was to clarify characteristics of post-encephalopathic epilepsy (PEE) in children after acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), paying particular attention to precise diagnosis of seizure types. Among 262 children with acute encephalopathy/encephalitis registered in a database of the Tokai Pediatric Neurology Society between 2005 and 2012, 44 were diagnosed with AESD according to the clinical course and magnetic resonance imaging (MRI) findings and were included in this study. Medical records were reviewed to investigate clinical data, MRI findings, neurologic outcomes, and presence or absence of PEE. Seizure types of PEE were determined by both clinical observation by pediatric neurologists and ictal video-electroencephalography (EEG) recordings. Of the 44 patients after AESD, 10 (23%) had PEE. The period between the onset of encephalopathy and PEE ranged from 2 to 39 months (median 8.5 months). Cognitive impairment was more severe in patients with PEE than in those without. Biphasic seizures and status epilepticus during the acute phase of encephalopathy did not influence the risk of PEE. The most common seizure type of PEE on clinical observation was focal seizures (n = 5), followed by epileptic spasms (n = 4), myoclonic seizures (n = 3), and tonic seizures (n = 2). In six patients with PEE, seizures were induced by sudden unexpected sounds. Seizure types confirmed by ictal video-EEG recordings were epileptic spasms and focal seizures with frontal onset, and all focal seizures were startle seizures induced by sudden acoustic stimulation. Intractable daily seizures remain in six patients with PEE. We demonstrate seizure characteristics of PEE in children after AESD. Epileptic spasms and startle focal seizures are common seizure types. The specific seizure types may be determined by the pattern of diffuse subcortical white matter injury in AESD and age-dependent reorganization of the brain

  11. New technetium-99m generator technologies utilizing polyethylene glycol-based aqueous biphasic systems

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, R.D.; Bond, A.H.; Zhang, Jianhua [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Chemistry; Horwitz, P. [Argonne National Lab., IL (United States)

    1995-12-31

    Two new schemes for TcO{sub 4}{sup {minus}}/MoO{sub 4}{sup 2{minus}} separations from OH{sup {minus}} and MoO{sub 4}{sup 2{minus}} media using polyethylene glycol (PEG)-based aqueous biphasic systems (ABS) have been developed. The two most important salt solutions in current {sup 99m}Tc-generator technologies, OH{sup {minus}} and MoO{sub 4}{sup 2{minus}}, also salt out PEG to form ABS. In liquid/liquid PEG- ABS, pertechnetate can be separated from molybdate with separation factors as high as 10,000. Stripping is accomplished by reduction of the TcO{sub 4}{sup {minus}} and back extraction into a salt solution. the strip solution can be the salt of an imaging agent (e.g., Na{sub 4}HEDPA) and thus may, under the appropriate conditions, be injected directly into the human body. {sup 99m}TcO{sub 4}{sup {minus}} can also be concentrated from a dilute load solution of {sup 99}MoO{sub 4}{sup 2{minus}} in NaOH using an aqueous biphasic extraction chromatographic technique (ABEC). A rinse with K{sub 2}CO{sub 3} assures that all {sup 99}MoO{sub 4}{sup 2{minus}} is removed from the column and this is confirmed by a rapid drop in {sup 99}Mo activity by the fourth free column volume (fcv) of rinse. The {sup 99m}TcO{sub 4}{sup {minus}} is then eluted with water. This chromatographic separation affords 94% of the {sup 99m}TcO{sub 4}{sup {minus}} activity in 5 fcv, with the y spectrum showing less than 2 {times} 10{sup {minus}4} of the original {sup 99}Mo activity.

  12. Calcium oxalate stone and gout.

    Science.gov (United States)

    Marickar, Y M Fazil

    2009-12-01

    Gout is well known to be produced by increased uric acid level in blood. The objective of this paper is to assess the relationship between gout and calcium oxalate stone formation in the humans. 48 patients with combination of gout and calcium oxalate stone problem were included. The biochemical values of this group were compared with 38 randomly selected uric acid stone patients with gout, 43 stone patients with gout alone, 100 calcium oxalate stone patients without gout and 30 controls, making a total of 259 patients. Various biochemical parameters, namely serum calcium, phosphorus and uric acid and 24-h urine calcium, phosphorus, uric acid, oxalate, citrate and magnesium were analysed. ANOVA and Duncan's multiple-range tests were performed to assess statistical significance of the variations. The promoters of stone formation, namely serum calcium (P stone patients and gouty calcium oxalate stone patients compared to the non-gouty patients and controls. Urine oxalate (P stones patients. The inhibitor urine citrate (P stone gouty patients, followed by the gouty uric acid stone formers and gouty calcium oxalate stone patients. The high values of promoters, namely uric acid and calcium in the gouty stone patients indicate the tendency for urinary stone formation in the gouty stone patients. There is probably a correlation between gout and calcium oxalate urinary stone. We presume this mechanism is achieved through the uric acid metabolism. The findings point to the summation effect of metabolic changes in development of stone disease.

  13. Calcium Signaling in Taste Cells

    Science.gov (United States)

    Medler, Kathryn F.

    2014-01-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. PMID:25450977

  14. Ion reactivity of calcium-deficient hydroxyapatite in standard cell culture media.

    Science.gov (United States)

    Gustavsson, J; Ginebra, M P; Engel, E; Planell, J

    2011-12-01

    Solution-mediated surface reactions occur for most calcium phosphate-based biomaterials and may influence cellular response. A reasonable extrapolation of such processes observed in vitro to in vivo performance requires a deep understanding of the underlying mechanisms. We therefore systematically investigated the nature of ion reactivity of calcium-deficient hydroxyapatite (CDHA) by exposing it for different periods of time to standard cell culture media of different chemical composition (DMEM and McCoy medium, with and without osteogenic supplements and serum proteins). Kinetic ion interaction studies of principal extracellular ions revealed non-linear sorption of Ca²⁺ (∼50% sorption) and K⁺ (∼8%) as well as acidification of all media during initial contact with CDHA (48h). Interestingly, inorganic phosphorus (P(i)) was sorbed from McCoy medium (∼50%) or when using osteogenic media containing β-glycerophosphate, but not from DMEM medium. Non-linear sorption data could be perfectly described by pseudo-first-order and pseudo-second-order sorption models. At longer contact time (21 days), and with frequent renewal of culture medium, sorption of Ca²⁺ remained constant throughout the experiment, while sorption of P(i) gradually decreased in McCoy medium. In great contrast, CDHA began to release P(i) slowly with time when using DMEM medium. Infrared spectra showed that CDHA exposed to culture media had a carbonated surface chemistry, suggesting that carbonate plays a key role in the ion reactivity of CDHA. Our data show that different compositions of the aqueous environment may provoke opposite ion reactivity of CDHA, and this must be carefully considered when evaluating the osteoinductive potential of the material. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. Comb polymer architecture and particle size effects on the behavior of biphasic nanoparticle inks for direct-write assembly

    Science.gov (United States)

    Yoshikawa, Jun

    Biphasic nanoparticle mixtures composed of attractive and repulsive colloidal species enable the direct-write assembly of 3D structures with much finer features than those produced by pure colloidal gels. These mixtures rely on the use of comb polymer dispersants to render one particle population stable, while the other population is attractive. In this thesis, we systematically investigate the effects of comb polymer architecture and particle size ratio on the behavior of biphasic nanoparticle inks with the overarching aim of further advancing the direct-write assembly of 3D colloidal structures. We first investigated the effects of both pure polyelectrolytes, poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA), and comb polymer dispersants composed of a PMAA backbone with methoxy-poly(ethylene oxide) (mPEO) teeth of varying molecular weights on the stability of barium titanate (BaTiO 3) suspensions. While each dispersant imparts stability to BaTiO 3 nanoparticles at low ionic strength (teeth (MWteeth = 2000) provides stability at higher ionic strengths over a broad range of particle sizes and counterion valencies. These results provide guidelines for tailoring the molecular architecture and functionality of comb polymer dispersants for optimal stabilization of the repulsive particle population within the biphasic inks. Next, particle size effects on the rheological properties of biphasic nanoparticle suspensions are studied. Shear elastic modulus, shear yield stress, and compressive yield stress are measured for mixtures of varying total volume fraction, attractive-to-repulsive volume fraction, and particle size ratio between attractive and repulsive species. Our observations indicate that the repulsive particles hinder the formation of the attractive gel network. The time required for shear elastic modulus to approach a steady-state value increases with the fraction of repulsive species. Furthermore, this behavior becomes more significant with increasing

  16. Cardiovascular Effects of Calcium Supplements

    Directory of Open Access Journals (Sweden)

    Ian R. Reid

    2013-07-01

    Full Text Available Calcium supplements reduce bone turnover and slow the rate of bone loss. However, few studies have demonstrated reduced fracture incidence with calcium supplements, and meta-analyses show only a 10% decrease in fractures, which is of borderline statistical and clinical significance. Trials in normal older women and in patients with renal impairment suggest that calcium supplements increase the risk of cardiovascular disease. To further assess their safety, we recently conducted a meta-analysis of trials of calcium supplements, and found a 27%–31% increase in risk of myocardial infarction, and a 12%–20% increase in risk of stroke. These findings are robust because they are based on pre-specified analyses of randomized, placebo-controlled trials and are consistent across the trials. Co-administration of vitamin D with calcium does not lessen these adverse effects. The increased cardiovascular risk with calcium supplements is consistent with epidemiological data relating higher circulating calcium concentrations to cardiovascular disease in normal populations. There are several possible pathophysiological mechanisms for these effects, including effects on vascular calcification, vascular cells, blood coagulation and calcium-sensing receptors. Thus, the non-skeletal risks of calcium supplements appear to outweigh any skeletal benefits, and are they appear to be unnecessary for the efficacy of other osteoporosis treatments.

  17. SR calcium handling and calcium after-transients in a rabbit model of heart failure

    NARCIS (Netherlands)

    Baartscheer, Antonius; Schumacher, Cees A.; Belterman, Charly N. W.; Coronel, Ruben; Fiolet, Jan W. T.

    2003-01-01

    Objective: After-depolarization associated arrhythmias are frequently observed in heart failure and associated with spontaneous calcium release from sarcoplasmic reticulum (SR), calcium after-transients. We hypothesize that disturbed SR calcium handling underlies calcium after-transients in heart

  18. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used in...

  19. 21 CFR 573.260 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does not...

  20. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  1. The Effects of Dietary Calcium and/or Iron Deficiency upon Murine Intestinal Calcium Binding Protein Activity and Calcium Absorption

    OpenAIRE

    McDonald, Catherine M.

    1980-01-01

    Iron deficiency has been shown to impair calcium absorption, leading to decreased bone mass. Vitamin D3-dependent calcium binding protein (CaBP) has been demonstrated to be necessary for the active transport of calcium in the intestine of numerous species. Iron deficiency might affect the activity of the calcium binding protein. Four experimental diets were formulated as follows: Diet 1, iron adequate, calcium adequate; Diet 2, iron deficient, calcium adequate; Diet 3, iron adequate, calci...

  2. Biomimetic synthesis of modified calcium phosphate fine powders and their in vitro studies

    Energy Technology Data Exchange (ETDEWEB)

    Gergulova, R., E-mail: rumigg@yahoo.com; Tepavitcharova, S., E-mail: rumigg@yahoo.com; Rabadjieva, D., E-mail: rumigg@yahoo.com; Sezanova, K., E-mail: rumigg@yahoo.com; Ilieva, R., E-mail: rumigg@yahoo.com [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia (Bulgaria); Alexandrova, R.; Andonova-Lilova, B. [Institute of Experimental Morphology, Pathology and Anthropology with Museum, BAS, Acad. G. Bonchev Str., Bl. 25, Sofia (Bulgaria)

    2013-12-16

    Biomimetic approach and subsequent high-temperature treatment were used to synthesize ion modified calcium phosphate fine powders. Thus, using Simulated Body Fluid (SBF) as an ion modifier, a bi-phase mixture of ion modified β-tricalcium phosphate and hydroxyapatite (β-TCP + HA) was prepared. The use of SBF electrolyte solution enriched with Mg{sup 2+} or Zn{sup 2+} yielded monophase β-tricalcium phosphate additionally modified with Mg{sup 2+} or Zn{sup 2+} (Mg-β-TCP or Zn-β-TCP). The in vitro behavior of the prepared powders on cell viability and proliferation of murine BALB/c 3T3 fibroblasts and of human Lep 3 cells was studied by MTT test assays and Mosmann method after 72 h incubation. The relative cell viability was calculated.

  3. Ectopic osteoid and bone formation by three calcium-phosphate ceramics in rats, rabbits and dogs.

    Directory of Open Access Journals (Sweden)

    Liao Wang

    Full Text Available Calcium phosphate ceramics with specific physicochemical properties have been shown to induce de novo bone formation upon ectopic implantation in a number of animal models. In this study we explored the influence of physicochemical properties as well as the animal species on material-induced ectopic bone formation. Three bioceramics were used for the study: phase-pure hydroxyapatite (HA sintered at 1200°C and two biphasic calcium phosphate (BCP ceramics, consisting of 60 wt.% HA and 40 wt.% TCP (β-Tricalcium phosphate, sintered at either 1100°C or 1200°C. 108 samples of each ceramic were intramuscularly implanted in dogs, rabbits, and rats for 6, 12, and 24 weeks respectively. Histological and histomorphometrical analyses illustrated that ectopic bone and/or osteoid tissue formation was most pronounced in BCP sintered at 1100°C and most limited in HA, independent of the animal model. Concerning the effect of animal species, ectopic bone formation reproducibly occurred in dogs, while in rabbits and rats, new tissue formation was mainly limited to osteoid. The results of this study confirmed that the incidence and the extent of material-induced bone formation are related to both the physicochemical properties of calcium phosphate ceramics and the animal model.

  4. Synthesis, characterization, and in-vitro cytocompatibility of amorphous β-tri-calcium magnesium phosphate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Satish S., E-mail: sss42@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Roy, Abhijit, E-mail: abr20@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Lee, Boeun, E-mail: bol11@pitt.edu [Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Banerjee, Ipsita [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261 (United States)

    2016-10-01

    Biphasic mixtures of crystalline β-tricalcium magnesium phosphate (β-TCMP) and an amorphous calcium magnesium phosphate have been synthesized and reported to support enhanced hMSC differentiation in comparison to β-tricalcium phosphate (β-TCP) due to the release of increased amounts of bioactive ions. In the current study, completely amorphous β-TCMP has been synthesized which is capable of releasing increased amounts of Mg{sup 2+} and PO{sub 4}{sup 3−} ions, rather than a biphasic mixture as earlier reported. The amorphous phase formed was observed to crystallize between temperatures of 400–600 °C. The scaffolds prepared with amorphous β-TCMP were capable of supporting enhanced hMSC proliferation and differentiation in comparison to commercially available β-TCP. However, a similar gene expression of mature osteoblast markers, OCN and COL-1, in comparison to biphasic β-TCMP was observed. To further study the role of Mg{sup 2+} and PO{sub 4}{sup 3−} ions in regulating hMSC osteogenic differentiation, the capability of hMSCs to mineralize in growth media supplemented with Mg{sup 2+} and PO{sub 4}{sup 3−} ions was studied. Interestingly, 5 mM PO{sub 4}{sup 3−} supported mineralization while the addition of 5 mM Mg{sup 2+} to 5 mM PO{sub 4}{sup 3−} inhibited mineralization. It was therefore concluded that the release of Ca{sup 2+} ions from β-TCMP scaffolds also plays a role in regulating osteogenic differentiation on these scaffolds and it is noted that further work is required to more accurately determine the exact role of Mg{sup 2+} in regulating hMSC osteogenic differentiation. - Highlights: • Synthesis of amorphous Mg containing beta tricalcium phosphate ceramics • Amorphous beta TCMP supports enhanced hMSC proliferation and differentiation. • Amorphous beta TCMP shows comparable OCN and COL-1 expression to biphasic TCMP. • Presence of 5 mM Mg{sup 2+} and PO{sub 4}{sup 3−} ions in growth media inhibits hMSC mineralization.

  5. Calcium, vitamin D, and your bones

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000490.htm Calcium, vitamin D, and your bones To use the sharing ... and maintain strong bones. How Much Calcium and Vitamin D do I Need? Amounts of calcium are ...

  6. Calcium Supplements: Do Men Need Them Too?

    Science.gov (United States)

    ... Lifestyle Nutrition and healthy eating Should men take calcium supplements? Answers from Katherine Zeratsky, R.D., L. ... Most healthy men don't need to take calcium supplements. Calcium is important for men for optimal ...

  7. Calcium transport in turtle bladder

    International Nuclear Information System (INIS)

    Sabatini, S.; Kurtzman, N.A.

    1987-01-01

    Unidirectional 45 Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (J net Ca ) was secretory (serosa to mucosa). Ouabain reversed J net Ca to an absorptive flux. Amiloride reduced both fluxes such that J net Ca was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, J net Ca decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, J net Ca was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45 Ca content was ≅30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca 2+ -ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na + -K + -ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa

  8. Calcium chromate process related investigations

    International Nuclear Information System (INIS)

    Dillard, B.M.

    1979-01-01

    A pilot plant for production of calcium chromate has been scaled up to a small production facility at the General Electric Neutron Devices Department. In preparation for this scale-up, the process and final product were studied in order to evaluate problems not considered previously. The variables and processes studied included: (1) the determination of optimum drying temperature and time for product analysis; (2) the effect of the grade of lime used as the precipitating agent on the purity of the calcium chromate; (3) product purity when calcium chromate is precipitated by the addition of ammonium chromate to slaked lime; (4) the reagents best suited for cleaning calcium chromate spills; and (5) methods for determining hydroxide ion concentration in calcium chromate. The optimum drying time for the product before analysis is four hours at 600 0 C. Gases evolved at various temperatures during the drying process were carbon dioxide and water vapor. Technical grade lime produced calcium chromate of the highest purity. Both nitric and acetic acids were efficient dissolvers of calcium chromate spills. Direct titration of hydroxide ion with sulfuric acid gave an average recovery of 93% for samples spiked with calcium hydroxide. 1 figure, 17 tables

  9. Irradiation induces a biphasic expression of pro-inflammatory cytokines in the lung

    International Nuclear Information System (INIS)

    Ruebe, C.E.; Wilfert, F.; Palm, J.; Burdak-Rothkamm, S.; Ruebe, C.; Koenig, J.; Liu Li; Schuck, A.; Willich, N.

    2004-01-01

    Background and purpose: the precise pathophysiological mechanisms of radiation-induced lung injury are poorly understood, but have been shown to correlate with dysregulation of different cytokines. The purpose of this study was to evaluate the time course of the pro-inflammatory cytokines tumor necrosis factor-(TNF-)α, interleukin-(IL)-1α and IL-6 after whole-lung irradiation. Material and methods: the thoraces of C57BL/6J mice were irradiated with 12 Gy. Treated and control mice were sacrificed at 0.5, 1, 3, 6, 12, 24, 48, 72 h, 1, 2, 4, 8, 16, and 24 weeks post irradiation (p.i.). Real-time multiplex RT-PCR (reverse transcriptase polmyerase chain reaction) was established to evaluate the expression of TNF-α, IL-1α and IL-6 in the lung tissue of the mice. For histological analysis, lung tissue sections were stained by hematoxylin and eosin. Results: multiplex RT-PCR analysis revealed a biphasic expression of these pro-inflammatory cytokines in the lung tissue after irradiation. After an initial increase at 1 h p.i. for TNF-α and at 6 h p.i. for IL-1α and IL-6, the mRNA expression of these pro-inflammatory cytokines returned to basal levels (48 h, 72 h, 1 week, 2 weeks p.i.). During the pneumonic phase, TNF-α, IL-1α and IL-6 were significantly elevated and revealed their maximum at 8 weeks p.i. Histopathologic evaluation of the lung sections obtained within 4 weeks p.i. revealed only minor lung damage in 5-30% of the lung tissue. By contrast, at 8, 16, and 24 weeks p.i., 70-90% of the lung tissue revealed histopathologically detectable organizing alveolitis. Conclusion: irradiation induces a biphasic expression of pro-inflammatory cytokines in the lung. The initial transitory cytokine response occurred within the first hours after lung irradiation with no detectable histopathologic alterations. The second, more persistent cytokine elevation coincided with the onset of histologically discernible organizing acute pneumonitis. (orig.)

  10. Irradiation induces a biphasic expression of pro-inflammatory cytokines in the lung

    Energy Technology Data Exchange (ETDEWEB)

    Ruebe, C.E.; Wilfert, F.; Palm, J.; Burdak-Rothkamm, S.; Ruebe, C. [Dept. of Radiotherapy - Radiooncology, Saarland Univ., Homburg/Saar (Germany); Koenig, J. [Inst. of Medical Biometrics, Epidemiology and Medical Informatics, Saarland Univ., Homburg/Saar (Germany); Liu Li [Dept. of Radiotherapy - Radiooncology, Saarland Univ., Homburg/Saar (Germany); Cancer Center, Union Hospital Tongji Medical Coll., Huazhong Univ. of Science and Technology, Wuhan (China); Schuck, A.; Willich, N. [Dept. of Radiotherapy - Radiooncology, Univ. of Muenster (Germany)

    2004-07-01

    Background and purpose: the precise pathophysiological mechanisms of radiation-induced lung injury are poorly understood, but have been shown to correlate with dysregulation of different cytokines. The purpose of this study was to evaluate the time course of the pro-inflammatory cytokines tumor necrosis factor-(TNF-){alpha}, interleukin-(IL)-1{alpha} and IL-6 after whole-lung irradiation. Material and methods: the thoraces of C57BL/6J mice were irradiated with 12 Gy. Treated and control mice were sacrificed at 0.5, 1, 3, 6, 12, 24, 48, 72 h, 1, 2, 4, 8, 16, and 24 weeks post irradiation (p.i.). Real-time multiplex RT-PCR (reverse transcriptase polmyerase chain reaction) was established to evaluate the expression of TNF-{alpha}, IL-1{alpha} and IL-6 in the lung tissue of the mice. For histological analysis, lung tissue sections were stained by hematoxylin and eosin. Results: multiplex RT-PCR analysis revealed a biphasic expression of these pro-inflammatory cytokines in the lung tissue after irradiation. After an initial increase at 1 h p.i. for TNF-{alpha} and at 6 h p.i. for IL-1{alpha} and IL-6, the mRNA expression of these pro-inflammatory cytokines returned to basal levels (48 h, 72 h, 1 week, 2 weeks p.i.). During the pneumonic phase, TNF-{alpha}, IL-1{alpha} and IL-6 were significantly elevated and revealed their maximum at 8 weeks p.i. Histopathologic evaluation of the lung sections obtained within 4 weeks p.i. revealed only minor lung damage in 5-30% of the lung tissue. By contrast, at 8, 16, and 24 weeks p.i., 70-90% of the lung tissue revealed histopathologically detectable organizing alveolitis. Conclusion: irradiation induces a biphasic expression of pro-inflammatory cytokines in the lung. The initial transitory cytokine response occurred within the first hours after lung irradiation with no detectable histopathologic alterations. The second, more persistent cytokine elevation coincided with the onset of histologically discernible organizing acute

  11. Square biphasic pulse deep brain stimulation for essential tremor: The BiP tremor study.

    Science.gov (United States)

    De Jesus, Sol; Almeida, Leonardo; Shahgholi, Leili; Martinez-Ramirez, Daniel; Roper, Jaimie; Hass, Chris J; Akbar, Umer; Wagle Shukla, Aparna; Raike, Robert S; Okun, Michael S

    2018-01-01

    Conventional deep brain stimulation (DBS) utilizes regular, high frequency pulses to treat medication-refractory symptoms in essential tremor (ET). Modifications of DBS pulse shape to achieve improved effectiveness is a promising approach. The current study assessed the safety, tolerability and effectiveness of square biphasic pulse shaping as an alternative to conventional ET DBS. This pilot study compared biphasic pulses (BiP) versus conventional DBS pulses (ClinDBS). Eleven ET subjects with clinically optimized ventralis intermedius nucleus DBS were enrolled. Objective measures were obtained over 3 h while ON BiP stimulation. There was observed benefit in the Fahn-Tolosa Tremor Rating Scale (TRS) for BiP conditions when compared to the DBS off condition and to ClinDBS setting. Total TRS scores during the DBS OFF condition (28.5 IQR = 24.5-35.25) were significantly higher than the other time points. Following active DBS, TRS improved to (20 IQR = 13.8-24.3) at ClinDBS setting and to (16.5 IQR = 12-20.75) at the 3 h period ON BiP stimulation (p = 0.001). Accelerometer recordings revealed improvement in tremor at rest (χ 2  = 16.1, p = 0.006), posture (χ 2  = 15.9, p = 0.007) and with action (χ 2  = 32.1, p=<0.001) when comparing median total scores at ClinDBS and OFF DBS conditions to 3 h ON BiP stimulation. There were no adverse effects and gait was not impacted. BiP was safe, tolerable and effective on the tremor symptoms when tested up to 3 h. This study demonstrated the feasibility of applying a novel DBS waveform in the clinic setting. Larger prospective studies with longer clinical follow-up will be required. Copyright © 2017. Published by Elsevier Ltd.

  12. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...... in the char conversion process. Comprehensive global equilibrium calculations predicted important characteristics of the inorganic ash residue. Equilibrium calculations predict the formation of liquid salt if sufficient amounts of Ca are added and according to experiments as well as calculations calcium binds...

  13. Selective use of the biphasic-contrast barium enema study for evaluation of colonic lesions: Results of a prospective study

    International Nuclear Information System (INIS)

    De Lange, E.E.; Shaffer, H.A. Jr.; Riddervold, H.O.

    1987-01-01

    The authors performed a prospective study to determine the value of selective use of the biphasic contrast technique for a variety of indications. In a series of 571 double-contrast barium enema examinations, the examination was immediately followed by a single-contrast study in 85 cases. The biphasic procedure was performed to reexamine a colonic segment that was poorly evaluated initially because of diverticulosis (eta = 35), incomplete filling (eta = 28), or poor mucosal coating (eta = 26); or to verify or exclude a possible lesion identified during the double-contrast examination (eta = 22). The single-contrast study confirmed five polyps and excluded lesions in 17 cases with suspected polyps (eta = 5), strictures (eta = 4), and spasm (eta = 8). Six polyps not visualized on the double-contrast examination were detected with the single-contrast procedure

  14. Species dependent radiotracer study of Cr(VI) and Cr(III) using an aqueous biphasic system

    Energy Technology Data Exchange (ETDEWEB)

    Roy, K.; Lahiri, S. [Chemical Sciences Div., Saha Inst. of Nuclear Physics, Kolkata (India)

    2008-07-01

    The speciation study of Cr(III) and Cr(VI) was carried out using a polyethylene glycol (PEG) based aqueous biphasic extraction system (ABS). Neutron activated Cr(III) and Cr(VI) salts were assayed in a HPGe detector before and after employing aqueous biphasic extraction. Different salts of various salting out abilities were taken as the salt rich phase. The best condition for extraction of Cr(VI) and the maximum differential attitude of ABS to Cr(VI) and Cr(III) was observed when 2 M Na{sub 2}SO{sub 4} and PEG 4000 (50% w/w) solutions were used. Cr(III) can also be extracted by the PEG with prior complexation with diphenylthiocarbazone (dithizone). The chromium dithizonate complex is quantitatively extracted by the PEG rich phase. (orig.)

  15. Catalytic conversion of corncob and corncob pretreatment hydrolysate to furfural in a biphasic system with addition of sodium chloride.

    Science.gov (United States)

    Qing, Qing; Guo, Qi; Zhou, Linlin; Wan, Yilun; Xu, Youqing; Ji, Huilong; Gao, Xiaohang; Zhang, Yue

    2017-02-01

    Catalytic conversion of corncob pretreatment hydrolysate and raw corncob into furfural in a modified biphasic system by SO 4 2- /SnO 2 - MMT solid catalyst has been developed. The influence of the organic solvent type, organic to water phase ratio, sodium chloride concentration, reaction temperature and time on the furfural production were comparatively evaluated. The results showed that furfural yields of 81.7% and 66.1% were achieved at 190°C for 15mins and 190°C for 20mins, respectively, for corncob pretreatment hydrolysate and raw corncob by this solid catalyst. The solid catalyst used in this study exhibited good stability and high efficiency applied in the modified biphasic system in addition to excellent recyclability. The proposed catalytic system displayed high performance for catalytic conversion of lignocellulosic biomass into important platform chemicals and has great potential in industrial application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Posterior mediastinal biphasic synovial sarcoma in a 12 year-old boy: A case report and review of literature

    Directory of Open Access Journals (Sweden)

    Pal Madhumay

    2010-01-01

    Full Text Available We report a case of biphasic synovial sarcoma of the mediastinum, a very rare tumor, in a 12-year-old boy with left-sided chest pain of 3 years duration at presentation. Chest X-ray showed left-sided opacity with loss of cardiac silhouette and the mediastinum deviated to the opposite side. Computed tomography (CT of thorax showed left-sided posterior mediastinal mass with left-sided pleural effusion and pleural thickening. CT guided fine needle aspiration cytology (FNAC from the mass reported it as spindle cell variant of adenocarcinoma. Ultrasonography (USG of the whole abdomen revealed no abnormality. The mediastinal tumor was resected by left thoracotomy and histopathological report confirmed it to be a biphasic synovial sarcoma with capsule invasion at places.

  17. Hierarchical Fabrication of Engineered Vascularized Bone Biphasic Constructs via Dual 3D Bioprinting: Integrating Regional Bioactive Factors into Architectural Design.

    Science.gov (United States)

    Cui, Haitao; Zhu, Wei; Nowicki, Margaret; Zhou, Xuan; Khademhosseini, Ali; Zhang, Lijie Grace

    2016-09-01

    A biphasic artificial vascularized bone construct with regional bioactive factors is presented using dual 3D bioprinting platform technique, thereby forming a large functional bone grafts with organized vascular networks. Biocompatible mussel-inspired chemistry and "thiol-ene" click reaction are used to regionally immobilize bioactive factors during construct fabrication for modulating or improving cellular events. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Biphasic whole-cell synthesis of R-2-octanol with recycling of the ionic liquid

    OpenAIRE

    Dennewald, Danielle

    2011-01-01

    Whole-cell biocatalysis in biphasic systems permits the synthesis of inhibiting chiral alcohols if appropriate non-water miscible ionic liquids are used. Taking the asymmetric reduction of 2-octanone to R-2-octanol by a recombinant Escherichia coli as a model reaction, a detailed characterisation of the biocatalytic reaction was performed with [HMPL][NTF] as ionic liquid. This made the asymmetric synthesis of R-2-octanol in a simple batch at a conversion > 99 % and at an enantiomeric excess >...

  19. Production of Phytotoxic Metabolite Using Biphasic Fermentation System from Strain C1136 of Lasiodiplodia pseudotheobromae, a Potential Bioherbicidal Agent

    OpenAIRE

    Charles Oluwaseun ADETUNJI; Julius Kola OLOKE; Gandham PRASAD; Moses ABALAKA; Emenike Onyebum IROKANULO

    2017-01-01

    Formulation of effective and environmental friendly bioherbicides depends on the type of fermentation medium used for the production of phytotoxic metabolites. The effect of biomass, colony forming unit and the phytotoxic metabolite produced from the biphasic fermentation was carried out, while the phytotoxic metabolite was tested in vivo and in-vitro on Echinochola crus-galli and dicotyledonous Chromolaena odorata. The mutant strain of Lasiodiplodia pseudotheobromae C1136 (Lp90) produced th...

  20. A Biphasic Pleural Tumor with Features of an Epithelioid and Small Cell Mesothelioma: Morphologic and Molecular Findings

    Directory of Open Access Journals (Sweden)

    Sarah Hackman

    2016-01-01

    Full Text Available Malignant mesotheliomas are generally classified into epithelioid, sarcomatoid, desmoplastic, and biphasic types with rare reports of a small cell form. These small cell variants display some morphologic overlap with desmoplastic small round cell tumors (DSRCTs which generally occur within the abdominal cavity of young males and are defined by a characteristic t(11;22(p13;q12 translocation. However, there are rare reports of DSRCTs lacking this translocation. We present a 78-year-old man with a pleura-based biphasic neoplasm with features of both epithelioid mesothelioma and a small cell blastema-like neoplasm. The epithelioid portion showed IHC reactivity for pan cytokeratin, CK5/6, D2-40, and calretinin and the small cell portion marked with CD99, pan cytokeratin, WT1, FLI1, S100, CD200, MyoD1, and CD15. Fluorescence in situ hybridization testing for the t(11;22(p13;q12 translocation disclosed loss of the EWSR1 gene in 94% of tumor cell nuclei, but there was no evidence of the classic translocation. Array based-comparative genomic hybridization (a-CGH confirmed the tumor had numerous chromosome copy number losses, including 11p15.5-p11.12 and 22q12.1-q13.33, with loss of the EWSR1 and WT1 gene regions. Herein, we report novel complex CGH findings in a biphasic tumor and review the molecular genetic alterations in both mesothelioma and DSRCTs.

  1. Design and development of a low-cost biphasic charge-balanced functional electric stimulator and its clinical validation.

    Science.gov (United States)

    Shendkar, Chandrashekhar; Lenka, Prasanna K; Biswas, Abhishek; Kumar, Ratnesh; Mahadevappa, Manjunatha

    2015-10-01

    Functional electric stimulators that produce near-ideal, charge-balanced biphasic stimulation waveforms with interphase delay are considered safer and more efficacious than conventional stimulators. An indigenously designed, low-cost, portable FES device named InStim is developed. It features a charge-balanced biphasic single channel. The authors present the complete design, mathematical analysis of the circuit and the clinical evaluation of the device. The developed circuit was tested on stroke patients affected by foot drop problems. It was tested both under laboratory conditions and in clinical settings. The key building blocks of this circuit are low dropout regulators, a DC-DC voltage booster and a single high-power current source OP-Amp with current-limiting capabilities. This allows the device to deliver high-voltage, constant current, biphasic pulses without the use of a bulky step-up transformer. The advantages of the proposed design over the currently existing devices include improved safety features (zero DC current, current-limiting mechanism and safe pulses), waveform morphology that causes less muscle fatigue, cost-effectiveness and compact power-efficient circuit design with minimal components. The device is also capable of producing appropriate ankle dorsiflexion in patients having foot drop problems of various Medical Research Council scale grades.

  2. Biphasic role of chondroitin sulfate in cardiac differentiation of embryonic stem cells through inhibition of Wnt/β-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Robert D Prinz

    Full Text Available The glycosaminoglycan chondroitin sulfate is a critical component of proteoglycans on the cell surface and in the extracellular matrix. As such, chondroitin sulfate side chains and the sulfation balance of chondroitin play important roles in the control of signaling pathways, and have a functional importance in human disease. In contrast, very little is known about the roles of chondroitin sulfate molecules and sulfation patterns during mammalian development and cell lineage specification. Here, we report a novel biphasic role of chondroitin sulfate in the specification of the cardiac cell lineage during embryonic stem cell differentiation through modulation of Wnt/beta-catenin signaling. Lineage marker analysis demonstrates that enzymatic elimination of endogenous chondroitin sulfates leads to defects specifically in cardiac differentiation. This is accompanied by a reduction in the number of beating cardiac foci. Mechanistically, we show that endogenous chondroitin sulfate controls cardiac differentiation in a temporal biphasic manner through inhibition of the Wnt/beta-catenin pathway, a known regulatory pathway for the cardiac lineage. Treatment with a specific exogenous chondroitin sulfate, CS-E, could mimic these biphasic effects on cardiac differentiation and Wnt/beta-catenin signaling. These results establish chondroitin sulfate and its sulfation balance as important regulators of cardiac cell lineage decisions through control of the Wnt/beta-catenin pathway. Our work suggests that targeting the chondroitin biosynthesis and sulfation machinery is a novel promising avenue in regenerative strategies after heart injury.

  3. Biphasic role of chondroitin sulfate in cardiac differentiation of embryonic stem cells through inhibition of Wnt/β-catenin signaling.

    Science.gov (United States)

    Prinz, Robert D; Willis, Catherine M; van Kuppevelt, Toin H; Klüppel, Michael

    2014-01-01

    The glycosaminoglycan chondroitin sulfate is a critical component of proteoglycans on the cell surface and in the extracellular matrix. As such, chondroitin sulfate side chains and the sulfation balance of chondroitin play important roles in the control of signaling pathways, and have a functional importance in human disease. In contrast, very little is known about the roles of chondroitin sulfate molecules and sulfation patterns during mammalian development and cell lineage specification. Here, we report a novel biphasic role of chondroitin sulfate in the specification of the cardiac cell lineage during embryonic stem cell differentiation through modulation of Wnt/beta-catenin signaling. Lineage marker analysis demonstrates that enzymatic elimination of endogenous chondroitin sulfates leads to defects specifically in cardiac differentiation. This is accompanied by a reduction in the number of beating cardiac foci. Mechanistically, we show that endogenous chondroitin sulfate controls cardiac differentiation in a temporal biphasic manner through inhibition of the Wnt/beta-catenin pathway, a known regulatory pathway for the cardiac lineage. Treatment with a specific exogenous chondroitin sulfate, CS-E, could mimic these biphasic effects on cardiac differentiation and Wnt/beta-catenin signaling. These results establish chondroitin sulfate and its sulfation balance as important regulators of cardiac cell lineage decisions through control of the Wnt/beta-catenin pathway. Our work suggests that targeting the chondroitin biosynthesis and sulfation machinery is a novel promising avenue in regenerative strategies after heart injury.

  4. Evolution of the Calcium Paradigm: The Relation between Vitamin D, Serum Calcium and Calcium Absorption

    Directory of Open Access Journals (Sweden)

    Borje E. Christopher Nordin

    2010-09-01

    Full Text Available Osteoporosis is the index disease for calcium deficiency, just as rickets/osteomalacia is the index disease for vitamin D deficiency, but there is considerable overlap between them. The common explanation for this overlap is that hypovitaminosis D causes malabsorption of calcium which then causes secondary hyperparathyroidism and is effectively the same thing as calcium deficiency. This paradigm is incorrect. Hypovitaminosis D causes secondary hyperparathyroidism at serum calcidiol levels lower than 60 nmol/L long before it causes malabsorption of calcium because serum calcitriol (which controls calcium absorption is maintained until serum calcidiol falls below 20 nmol/L. This secondary hyperparathyroidism, probably due to loss of a “calcaemic” action of vitamin D on bone first described in 1957, destroys bone and explains why vitamin D insufficiency is a risk factor for osteoporosis. Vitamin D thus plays a central role in the maintenance of the serum (ionised calcium, which is more important to the organism than the preservation of the skeleton. Bone is sacrificed when absorbed dietary calcium does not match excretion through the skin, kidneys and bowel which is why calcium deficiency causes osteoporosis in experimental animals and, by implication, in humans.

  5. Aerosol Particle Interfacial Thermodynamics and Phase Partitioning Measurements Using Biphasic Microfluidics

    Science.gov (United States)

    Dutcher, Cari; Metcalf, Andrew

    2015-03-01

    Secondary organic aerosol particles are nearly ubiquitous in the atmosphere and yet there remain large uncertainties in their formation processes and ambient properties. These particles are complex microenvironments, which can contain multiple interfaces due to internal aqueous-organic phase partitioning and to the external liquid-vapor surface. Interfacial properties affect the ambient aerosol morphology, or internal structure of the particle, which in turn can affect the way a particle interacts with an environment of condensable clusters and organic vapors. To improve our ability to accurately predict ambient aerosol morphology, we must improve our knowledge of aerosol interfaces and their interactions with the ambient environment. Unfortunately, many techniques employed to measure interfacial properties do so in bulk solutions or in the presence of a ternary (e.g. solid) phase. In this talk, a novel method using biphasic microscale flows will be introduced for generating, trapping, and perturbing complex interfaces at atmospherically relevant conditions. These microfluidic experiments utilize high-speed imaging to monitor interfacial phenomena at the microscale and are performed with phase contrast and fluorescence microscopy on a temperature-controlled inverted microscope stage. From these experiments, interfacial thermodynamic properties such as surface or interfacial tension, rheological properties such as interfacial moduli, and kinetic properties such as mass transfer coefficients can be measured or inferred.

  6. Development of modified-release tablets of zolpidem tartrate by biphasic quick/slow delivery system.

    Science.gov (United States)

    Mahapatra, Anjan Kumar; Sameeraja, N H; Murthy, P N

    2015-06-01

    Zolpidem tartrate is a non-benzodiazepine analogue of imidazopyridine of sedative and hypnotic category. It has a short half-life with usual dosage regimen being 5 mg, two times a day, or 10 mg, once daily. The duration of action is considered too short in certain circumstances. Thus, it is desirable to lengthen the duration of action. The formulation design was implemented by preparing extended-release tablets of zolpidem tartrate using the biphasic delivery system technology, where sodium starch glycolate acts as a superdisintegrant in immediate-release part and hydroxypropyl methyl cellulose as a release retarding agent in extended-release core. Tablets were prepared by direct compression. Both the core and the coat contained the drug. The pre-compression blends were evaluated for angle of repose, bulk density, and compressibility index. The tablets were evaluated for thickness, hardness, weight variation test, friability, and in vitro release studies. No interaction was observed between zolpidem tartrate and excipients from the Fourier transform infrared spectroscopy and differential scanning calorimetry analysis. The results of all the formulations prepared were compared with reference product Stilnoct®. Optimized formulations showed release patterns that match the United States Pharmacopeia (USP) guidelines for zolpidem tartrate extended-release tablets. The mechanism of drug release was studied using different mathematical models, and the optimized formulation has shown Fickian diffusion. Accelerated stability studies were performed on the optimized formulation.

  7. Airway pressure release ventilation and biphasic positive airway pressure: a systematic review of definitional criteria.

    Science.gov (United States)

    Rose, Louise; Hawkins, Martyn

    2008-10-01

    The objective of this study was to identify the definitional criteria for the pressure-limited and time-cycled modes: airway pressure release ventilation (APRV) and biphasic positive airway pressure (BIPAP) available in the published literature. Systematic review. Medline, PubMed, Cochrane, and CINAHL databases (1982-2006) were searched using the following terms: APRV, BIPAP, Bilevel and lung protective strategy, individually and in combination. Two independent reviewers determined the paper eligibility and abstracted data from 50 studies and 18 discussion articles. Of the 50 studies, 39 (78%) described APRV, and 11 (22%) described BIPAP. Various study designs, populations, or outcome measures were investigated. Compared to BIPAP, APRV was described more frequently as extreme inverse inspiratory:expiratory ratio [18/39 (46%) vs. 0/11 (0%), P = 0.004] and used rarely as a noninverse ratio [2/39 (5%) vs. 3/11 (27%), P = 0.06]. One (9%) BIPAP and eight (21%) APRV studies used mild inverse ratio (>1:1 to branding may further add to confusion. Generic naming of modes and consistent definitional parameters may improve consistency of patient response for a given mode and assist with clinical implementation.

  8. Enhanced refrigerant capacity in Gd-Al-Co microwires with a biphase nanocrystalline/amorphous structure

    Energy Technology Data Exchange (ETDEWEB)

    Shen, H. X. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Department of Physics, University of South Florida, Tampa, Florida 33620 (United States); Xing, D. W.; Liu, Y. F.; Sun, J. F. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sánchez Llamazares, J. L. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055 Col. Lomas 4a, San Luis Potosí, S.L.P. 78216 (Mexico); Sánchez-Valdés, C. F. [Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, AP 14, Ensenada 22860, Baja California (Mexico); Belliveau, H.; Srikanth, H.; Phan, M. H., E-mail: phanm@usf.edu [Department of Physics, University of South Florida, Tampa, Florida 33620 (United States); Wang, H.; Qin, F. X. [Institute for Composites Science and Innovation (InCSI), College of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2016-02-29

    A class of biphase nanocrystalline/amorphous Gd{sub (50+5x)}Al{sub (30−5x)}Co{sub 20} (x = 0, 1, 2) microwires fabricated directly by melt-extraction is reported. High resolution transmission electron microscopy and Fourier function transform based analysis indicate the presence of a volume fraction (∼20%) of ∼10 nm sized nanocrystallities uniformly embedded in an amorphous matrix. The microwires possess excellent magnetocaloric properties, with large values of the isothermal entropy change (−ΔS{sub M} ∼ 9.7 J kg{sup −1} K{sup −1}), the adiabatic temperature change (ΔT{sub ad} ∼ 5.2 K), and the refrigerant capacity (RC ∼ 654 J kg{sup −1}) for a field change of 5 T. The addition of Gd significantly alters T{sub C} while preserving large values of the ΔS{sub M} and RC. The nanocrystallites allow for enhanced RC as well as a broader operating temperature span of a magnetic bed for energy-efficient magnetic refrigeration.

  9. Microstructure and phase evolution during the dealloying of bi-phase Al–Ag alloy

    International Nuclear Information System (INIS)

    Song, T.T.; Gao, Y.L.; Zhang, Z.H.; Zhai, Q.J.

    2013-01-01

    Highlights: ► Selective leaching of α-Al(Ag) and Ag 2 Al occurs simultaneously during dealloying. ► Diffusion of Al and vacancy controlled mechanism dominate the etching of Ag 2 Al. ► The coarsening of ligaments in NPS follows a time dependence of d ∝t 2/5 . - Abstract: The chemical dealloying of bi-phase Al-35Ag alloy has been investigated within the parting limit. The dealloying of α-Al(Ag) and Ag 2 Al commenced simultaneously, and all α-Al(Ag) and part of Ag 2 Al were dealloyed, leaving residual Ag 2 Al to be dealloyed afterwards. The dealloying of the residual Ag 2 Al is associated with vacancy controlled mechanism and diffusion of Al atoms. It is revealed that the diffusions of the Al and Ag atoms during dealloying are significant. The Ag skeletons formed at the initial stage, and became coarsened gradually with a time dependence of d ∝t 2/5 , illustrating the vital role of diffusion of Ag atoms.

  10. Biphasic Regulation of Lipid Metabolism: A Meta-Analysis of Icodextrin in Peritoneal Dialysis

    Directory of Open Access Journals (Sweden)

    Yan-Feng Huang

    2015-01-01

    Full Text Available Objectives. The objective of this systematic meta-analysis was to study the impact of icodextrin (ICO on lipid profiles. Methods. MEDLINE, PubMed, Embase, Chinese Biomedical Literature, and the Cochrane Library and Reference lists were searched (last search September 2014 in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. Results. Searches identified 13 eligible trials with a total of 850 patients. The differentials of total cholesterol (TC and free fatty acid (FFA in the ICO group were greater than those in the GLU group. Metaregression analysis showed that TC levels positively correlated with its baseline levels. In the subgroup of patients with dialysis duration more than 6 months, TC and TG in the ICO group were less. In pooled data from cross-sectional studies, differential of TG in the ICO group was less. In the subgroup of patients with diabetes (Martikainen et al., 2005, Sniderman et al., 2014, and Takatori et al., 2011, differential of high-density lipoprotein cholesterol (HDL-C in the ICO group was less. There was no significant effect on low-density lipoprotein cholesterol (LDL-C, very low-density lipoprotein cholesterol (VLDL-C, or lipoprotein(a. Conclusions. ICO may be beneficial to lipid metabolism, especially for its biphasic regulation of plasma TC levels.

  11. Biphasic dose responses in biology, toxicology and medicine: Accounting for their generalizability and quantitative features

    International Nuclear Information System (INIS)

    Calabrese, Edward J.

    2013-01-01

    The most common quantitative feature of the hormetic-biphasic dose response is its modest stimulatory response which at maximum is only 30–60% greater than control values, an observation that is consistently independent of biological model, level of organization (i.e., cell, organ or individual), endpoint measured, chemical/physical agent studied, or mechanism. This quantitative feature suggests an underlying “upstream” mechanism common across biological systems, therefore basic and general. Hormetic dose response relationships represent an estimate of the peak performance of integrative biological processes that are allometrically based. Hormetic responses reflect both direct stimulatory or overcompensation responses to damage induced by relatively low doses of chemical or physical agents. The integration of the hormetic dose response within an allometric framework provides, for the first time, an explanation for both the generality and the quantitative features of the hormetic dose response. -- Highlights: •The hormetic stimulation is at maximum 30–60% greater than control responses. •Hormesis is a measure of biological performance and plasticity. •The hormetic response is evolutionary based and highly generalizable. -- This paper provides a biologically based explanation for the generalizability/quantitative features of the hormetic dose response, representing a fundamental contribution to the field

  12. Study of volume fractions on biphasic stratified regime using gamma ray

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, William L.; Brandão, Luis E.B., E-mail: william.otero@hotmail.com, E-mail: brandao@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    In the oil industries, interconnected pipelines are used to carry large quantities of petroleum and its byproducts. This modal has an advantage because they are more economical, eliminate a need for stocks and, in addition, great safety in operation minimizing a possibility of loss or theft when transported another way. In many cases, especially in the petrochemical industry, the same pipeline is used to carry more than one type of product. They are called poliduct. In the operation of a poliduct there is a sequence of products to be transported and during the exchange of the product, there are still fractions of the previous product and this generates contamination. It is therefore important to identify precisely this region in order to reduce the costs of reprocessing and treatment of discarded products. In this way, this work presents a methodology to evaluate the sensitivity of the gamma densitometry technique in a study of the calculation of volume fractions in biphasic systems, submitted to the stratified flow regime. Using computational simulations using the Monte Carlo Method with the MCNPX code measurement geometry was proposed that presented a higher sensitivity for the calculation of volume fractions. The relevant technical data to perform a simulation of the scintillator detectors were based on information obtained from the gammagraphy technique. The study had a theoretical validation through analytical equations, and the results show that it is possible to identify volume fractions equivalent to 3%. (author)

  13. Liquid / liquid biphasic electrochemistry in ultra-turrax dispersed acetonitrile / aqueous electrolyte systems

    International Nuclear Information System (INIS)

    Watkins, John D.; Amemiya, Fumihiro; Atobe, Mahito; Bulman-Page, Philip C.; Marken, Frank

    2010-01-01

    Unstable acetonitrile | aqueous emulsions generated in situ with ultra-turrax agitation are investigated for applications in dual-phase electrochemistry. Three modes of operation for liquid / liquid aqueous-organic electrochemical processes are demonstrated with no intentionally added electrolyte in the organic phase based on (i) the formation of a water-soluble product in the aqueous phase in the presence of the organic phase, (ii) the formation of a product and ion transfer at the liquid / liquid-electrode triple phase boundary, and (iii) the formation of a water-insoluble product in the aqueous phase which then transfers into the organic phase. A three-electrode electrolysis cell with ultra-turrax agitator is employed and characterised for acetonitrile / aqueous 2 M NaCl two phase electrolyte. Three redox systems are employed in order to quantify the electrolysis cell performance. The one-electron reduction of Ru(NH 3 ) 6 3+ in the aqueous phase is employed to determine the rate of mass transport towards the electrode surface and the effect of the presence of the acetonitrile phase. The one-electron oxidation of n-butylferrocene in acetonitrile is employed to study triple phase boundary processes. Finally, the one-electron reduction of cobalticenium cations in the aqueous phase is employed to demonstrate the product transfer from the electrode surface into the organic phase. Potential applications in biphasic electrosynthesis are discussed.

  14. A flow reactor setup for photochemistry of biphasic gas/liquid reactions

    Directory of Open Access Journals (Sweden)

    Josef Schachtner

    2016-08-01

    Full Text Available A home-built microreactor system for light-mediated biphasic gas/liquid reactions was assembled from simple commercial components. This paper describes in full detail the nature and function of the required building elements, the assembly of parts, and the tuning and interdependencies of the most important reactor and reaction parameters. Unlike many commercial thin-film and microchannel reactors, the described set-up operates residence times of up to 30 min which cover the typical rates of many organic reactions. The tubular microreactor was successfully applied to the photooxygenation of hydrocarbons (Schenck ene reaction. Major emphasis was laid on the realization of a constant and highly reproducible gas/liquid slug flow and the effective illumination by an appropriate light source. The optimized set of conditions enabled the shortening of reaction times by more than 99% with equal chemoselectivities. The modular home-made flow reactor can serve as a prototype model for the continuous operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories.

  15. Disrupted glutamate-glutamine cycle in acute encephalopathy with biphasic seizures and late reduced diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Takanashi, Jun-ichi; Terai, Masaru [Tokyo Women' s Medical University Yachiyo Medical Center, Department of Pediatrics, Yachiyo-shi (Japan); Mizuguchi, Masashi [The University of Tokyo, Department of Developmental Medical Sciences, Graduate School of Medicine, Tokyo (Japan); Barkovich, A.J. [University of California San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States)

    2015-11-15

    Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype of infectious pediatric encephalopathy in Japan. It is sometimes difficult to make an early diagnosis of AESD; excitotoxicity is postulated to be the pathogenesis based on elevated glutamine (Gln) and glutamate (Glu) complex (Glx = Glu + Gln) observed on MR spectroscopy. It is uncertain whether Gln or Glu contributes to the elevated Glx, or whether MR spectroscopy is useful for an early diagnosis. Five Japanese patients with AESD (three boys and two girls, 1 year of age) were enrolled in this study. MR spectroscopy was acquired from the frontal white matter (repetition time (TR) of 5000 ms, echo time (TE) of 30 ms) with a 1.5- or 3.0-T scanner. MR spectroscopy was performed four times for two patients, three times for one patient, and two times for two patients. Quantification of Glu and Gln was performed using LCModel. Glu was elevated in three of four studies on days 1-4 and became normal or low afterward. Gln was normal in three studies on days 1-2, elevated in all seven studies on days 4-12, and became normal or low afterward. These findings suggest that MR spectroscopy may be useful for an early diagnosis. Acute Glu elevation changes to subacute Gln elevation, suggesting that a disrupted Glu-Gln cycle may play an important role. (orig.)

  16. [Development of biphasic drug-loading lipid emulsion of Salvia miltiorrhiza and its quality evaluation].

    Science.gov (United States)

    Wang, Yin-Yan; Li, Xi; Lai, Xiu-Jun; Li, Wei; Yang, Ya-Jing; Chu, Ting; Mao, Sheng-Jun

    2014-10-01

    The feasibility of simultaneously loading both liposoluble and water-soluble components of Salvia miltiorrhiza in emulsion was discussed, in order to provide new ideas in comprehensive application of effective components in S. miltiorrhiza in terms of technology of pharmaceutics. With tanshinone II (A) and salvianolic acid B as raw materials, soybean phospholipid and poloxamer 188 as emulsifiers, and glycerin as isoosmotic regulator, the central composite design-response surface method was employed to optimize the prescription. The coarse emulsion was prepared with the high-speed shearing method and then homogenized in the high pressure homogenizer. The biphasic drug-loading intravenous emulsion was prepared to investigate its pharmaceutical properties and stability. The prepared emulsion is orange-yellow, with the average diameter of 241 nm and Zeta potential of -35.3 mV. Specifically, the drug loading capacity of tanshinone II (A) and salvianolic acid B were 0.5 g x L(-1) and 1 g x L(-1), respectively, with a good stability among long-term retention samples. According to the results, the prepared emulsion could load liposoluble tanshinone II (A) and water-soluble salvianolic acid B simultaneously, which lays a pharmaceutical foundation for giving full play to the efficacy of S. miltiorrhiza.

  17. Possible biphasic sweating response during short-term heat acclimation protocol for tropical natives.

    Science.gov (United States)

    Magalhães, Flávio de Castro; Machado-Moreira, Christiano Antônio; Vimieiro-Gomes, Ana Carolina; Silami-Garcia, Emerson; Lima, Nilo Resende Viana; Rodrigues, Luiz Oswaldo Carneiro

    2006-05-01

    The aim of the present study was to evaluate the sweat loss response during short-term heat acclimation in tropical natives. Six healthy young male subjects, inhabitants of a tropical region, were heat acclimated by means of nine days of one-hour heat-exercise treatments (40+/-0 degrees C and 32+/-1% relative humidity; 50% (.)VO(2peak) on a cycle ergometer). On days 1 to 9 of heat acclimation whole-body sweat loss was calculated by body weight variation corrected for body surface area. On days 1 and 9 rectal temperature (T(re)) and heart rate (HR) were measured continuously, and rating of perceived exertion (RPE) every 4 minutes. Heat acclimation was confirmed by reduced HR (day 1 rest: 77+/-5 b.min(-1); day 9 rest: 68+/-3 b.min(-1); day 1 final exercise: 161+/-15 b.min(-1); day 9 final exercise: 145+/-11 b.min(-1), p0.05) of the protocol. These findings are consistent with the heat acclimation induced adaptations and suggest a biphasic sweat response (an increase in the sweat rate in the middle of the protocol followed by return to initial values by the end of it) during short-term heat acclimation in tropical natives.

  18. Forging And Milling Contribution On Residual Stresses For A Textured Biphasic Titanium Alloy

    International Nuclear Information System (INIS)

    Deleuze, C.; Fabre, A.; Barrallier, L.; Molinas, O.

    2011-01-01

    Ti-10V-2Fe-3Al is a biphasic titanium alloy (α+β) used in aeronautical applications for its mechanical properties, such as its yield strength of 1200 MPa and it weighs 40% less than steel. This alloy is particularly useful for vital parts with complex geometry, because of its high forging capability. In order to predict the capability for fatigue lifetime, the designers need to know the residual stresses. X-Ray diffraction is the main experimental technique used to determine residual stresses on the surface. In this case, stress levels are primarily influenced by the complex forging and milling process. On this alloy in particular, it may be difficult to characterize stress due to modification of the microstructure close to the surface. Results obtained by x-ray analysis depend on the correct definition of the shape of the diffraction peaks. The more precisely defined the position of the peak, the more accurately the stresses are evaluated. This paper presents a method to detect if residual stresses can be characterized by x-ray diffraction. The characterization of hardness seems to be a relevant technique to quickly analyze the capability of x-ray diffraction to determine residual stresses.

  19. Integration process of fermentation and liquid biphasic flotation for lipase separation from Burkholderia cepacia.

    Science.gov (United States)

    Sankaran, Revathy; Show, Pau Loke; Lee, Sze Ying; Yap, Yee Jiun; Ling, Tau Chuan

    2018-02-01

    Liquid Biphasic Flotation (LBF) is an advanced recovery method that has been effectively applied for biomolecules extraction. The objective of this investigation is to incorporate the fermentation and extraction process of lipase from Burkholderia cepacia using flotation system. Initial study was conducted to compare the performance of bacteria growth and lipase production using flotation and shaker system. From the results obtained, bacteria shows quicker growth and high lipase yield via flotation system. Integration process for lipase separation was investigated and the result showed high efficiency reaching 92.29% and yield of 95.73%. Upscaling of the flotation system exhibited consistent result with the lab-scale which are 89.53% efficiency and 93.82% yield. The combination of upstream and downstream processes in a single system enables the acceleration of product formation, improves the product yield and facilitates downstream processing. This integration system demonstrated its potential for biomolecules fermentation and separation that possibly open new opportunities for industrial production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Study of volume fractions on biphasic stratified regime using gamma ray

    International Nuclear Information System (INIS)

    Salgado, William L.; Brandão, Luis E.B.

    2017-01-01

    In the oil industries, interconnected pipelines are used to carry large quantities of petroleum and its byproducts. This modal has an advantage because they are more economical, eliminate a need for stocks and, in addition, great safety in operation minimizing a possibility of loss or theft when transported another way. In many cases, especially in the petrochemical industry, the same pipeline is used to carry more than one type of product. They are called poliduct. In the operation of a poliduct there is a sequence of products to be transported and during the exchange of the product, there are still fractions of the previous product and this generates contamination. It is therefore important to identify precisely this region in order to reduce the costs of reprocessing and treatment of discarded products. In this way, this work presents a methodology to evaluate the sensitivity of the gamma densitometry technique in a study of the calculation of volume fractions in biphasic systems, submitted to the stratified flow regime. Using computational simulations using the Monte Carlo Method with the MCNPX code measurement geometry was proposed that presented a higher sensitivity for the calculation of volume fractions. The relevant technical data to perform a simulation of the scintillator detectors were based on information obtained from the gammagraphy technique. The study had a theoretical validation through analytical equations, and the results show that it is possible to identify volume fractions equivalent to 3%. (author)

  1. A biphasic epigenetic switch controls immunoevasion, virulence and niche adaptation in non-typeable Haemophilus influenzae.

    Science.gov (United States)

    Atack, John M; Srikhanta, Yogitha N; Fox, Kate L; Jurcisek, Joseph A; Brockman, Kenneth L; Clark, Tyson A; Boitano, Matthew; Power, Peter M; Jen, Freda E-C; McEwan, Alastair G; Grimmond, Sean M; Smith, Arnold L; Barenkamp, Stephen J; Korlach, Jonas; Bakaletz, Lauren O; Jennings, Michael P

    2015-07-28

    Non-typeable Haemophilus influenzae contains an N(6)-adenine DNA-methyltransferase (ModA) that is subject to phase-variable expression (random ON/OFF switching). Five modA alleles, modA2, modA4, modA5, modA9 and modA10, account for over two-thirds of clinical otitis media isolates surveyed. Here, we use single molecule, real-time (SMRT) methylome analysis to identify the DNA-recognition motifs for all five of these modA alleles. Phase variation of these alleles regulates multiple proteins including vaccine candidates, and key virulence phenotypes such as antibiotic resistance (modA2, modA5, modA10), biofilm formation (modA2) and immunoevasion (modA4). Analyses of a modA2 strain in the chinchilla model of otitis media show a clear selection for ON switching of modA2 in the middle ear. Our results indicate that a biphasic epigenetic switch can control bacterial virulence, immunoevasion and niche adaptation in an animal model system.

  2. Biphasic threat to femoral head perfusion in abduction: arterial hypoperfusion and venous congestion

    Energy Technology Data Exchange (ETDEWEB)

    Yousefzadeh, David K. [Comer Children' s Hospital, Department of Radiology, Chicago, IL (United States); University of Chicago, Department of Radiology, Chicago, IL (United States); Jaramillo, Diego [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Johnson, Neil [Cincinnati Children' s Hospital, Department of Radiology, Cincinnati, OH (United States); Doerger, Kirk [Radiology Associates of Northern Kentucky, Crestview Hills, KY (United States); Sullivan, Christopher [University of Chicago, Department of Surgery, Chicago, IL (United States)

    2010-09-15

    Hip abduction can cause avascular necrosis (AVN) of the femoral head in infants. To compare the US perfusion pattern of femoral head cartilage in neutral position with that in different degrees and duration of abduction, testing the venous congestion theory of post-abduction ischemia. In 20 neonates, the Doppler flow characteristics of the posterosuperior (PS) branch of the femoral head cartilage feeding vessels were evaluated in neutral and at 30 , 45 , and 60 abduction. In three neonates the leg was held in 45-degree abduction and flow was assessed at 5, 10, and 15 min. Male/female ratio was 11/9 with a mean age of 1.86 {+-} 0.7 weeks. The peak systolic velocities (PSV) declined in all three degrees of abduction. After 15 min of 45-degree abduction, the mean PSV declined and showed an absent or reversed diastolic component and undetectable venous return. No perfusion was detected at 60-degree abduction. Abduction-induced femoral head ischemia is biphasic and degree- and duration-dependent. In phase I there is arterial hypoperfusion and in phase II there is venous congestion. A new pathogeneses for femoral head ischemia is offered. (orig.)

  3. Nanoscopic characterization of the water vapor-salt interfacial layer reveals a unique biphasic adsorption process

    Science.gov (United States)

    Yang, Liu; He, Jianfeng; Shen, Yi; Li, Xiaowei; Sun, Jielin; Czajkowsky, Daniel M.; Shao, Zhifeng

    2016-08-01

    Our quantitative understanding of water adsorption onto salt surfaces under ambient conditions is presently quite poor owing to the difficulties in directly characterizing this interfacial layer under these conditions. Here we determine the thickness of the interfacial layer on NaCl at different relative humidities (RH) based on a novel application of atomic force spectroscopy and capillary condensation theory. In particular, we take advantage of the microsecond-timescale of the capillary condensation process to directly resolve the magnitude of its contribution in the tip-sample interaction, from which the interfacial water thickness is determined. Further, to correlate this thickness with salt dissolution, we also measure surface conductance under similar conditions. We find that below 30% RH, there is essentially only the deposition of water molecules onto this surface, typical of conventional adsorption onto solid surfaces. However, above 30% RH, adsorption is simultaneous with the dissolution of ions, unlike conventional adsorption, leading to a rapid increase of surface conductance. Thus, water adsorption on NaCl is an unconventional biphasic process in which the interfacial layer not only exhibits quantitative differences in thickness but also qualitative differences in composition.

  4. Transient dysautonomia in an acute phase of encephalopathy with biphasic seizures and late reduced diffusion.

    Science.gov (United States)

    Ichimiya, Yuko; Kaku, Noriyuki; Sakai, Yasunari; Yamashita, Fumiya; Matsuoka, Wakato; Muraoka, Mamoru; Akamine, Satoshi; Mizuguchi, Soichi; Torio, Michiko; Motomura, Yoshitomo; Hirata, Yuichiro; Ishizaki, Yoshito; Sanefuji, Masafumi; Torisu, Hiroyuki; Takada, Hidetoshi; Maehara, Yoshihiko; Ohga, Shouichi

    2017-08-01

    Paroxysmal sympathetic hyperactivity (PSH) is a dysautonomic condition that is associated with various types of acquired brain injuries. Traumatic brain lesions have been documented as the leading cause of PSH. However, detailed clinical features of pediatric PSH caused by intrinsic brain lesions remain to be elusive. We present a 3-year-old boy, who had been diagnosed as having cerebral palsy, developmental delay and epilepsy after perinatal hypoxia-induced brain injury. He developed status epilepticus with fever on the third day of respiratory infection. Whereas the seizure was terminated by systemic infusion of midazolam, consciousness remained disturbed for the next 48h. Serial magnetic resonance imaging studies revealed that acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) evolved on 3days after the seizure. Therapeutic hypothermia was immediately introduced, however, the brain lesion extended to the whole subcortical white matters on day 8. The intermittent bilateral dilation of pupils with increased blood pressure and tachycardia were observed until day 12. Real-time monitoring of electroencephalograms ruled out the recurrent attacks of seizures. The abnormal signs of autonomic nervous system gradually ceased and never relapsed after recovery from the hypothermia. PSH or a transient condition of dysautonomia may emerge and persist during the acute phase of AESD. Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  5. Extraction of Biomolecules Using Phosphonium-Based Ionic Liquids + K3PO4 Aqueous Biphasic Systems

    Science.gov (United States)

    Louros, Cláudia L. S.; Cláudio, Ana Filipa M.; Neves, Catarina M. S. S.; Freire, Mara G.; Marrucho, Isabel M.; Pauly, Jérôme; Coutinho, João A. P.

    2010-01-01

    Aqueous biphasic systems (ABS) provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs) to form ABS with aqueous K3PO4 solutions was evaluated for the first time. Ternary phase diagrams, and respective tie-lines and tie-lines length, formed by distinct phosphonium-based ILs, water, and K3PO4 at 298 K, were measured and are reported. The studied phosphonium-based ILs have shown to be more effective in promoting ABS compared to the imidazolium-based counterparts with similar anions. Moreover, the extractive capability of such systems was assessed for distinct biomolecules (including amino acids, food colourants and alkaloids). Densities and viscosities of both aqueous phases, at the mass fraction compositions used for the biomolecules extraction, were also determined. The evaluated IL-based ABS have been shown to be prospective extraction media, particularly for hydrophobic biomolecules, with several advantages over conventional polymer-inorganic salt ABS. PMID:20480041

  6. Biphasic insulin-releasing effect of BTS 67 582 in rats.

    Science.gov (United States)

    Storey, D A; Bailey, C J

    1998-12-01

    BTS 67 582 (1,1-dimethyl-2(2-morpholinophenyl)guanidine fumarate) is being developed as a short-acting anti-diabetic insulin secretagogue. The effect of BTS 67 582 on the phasic pattern of insulin release was assessed in anaesthetized normal rats by measuring arterial plasma insulin concentrations while arterial glucose concentrations were fixed at 6, 8.5 and 12.5 mM. Intravenous BTS 67 582 (10 mg kg(-1)) induced an immediate but transient increase in insulin concentrations which declined by 10 min (first phase). This was followed by a smaller but sustained increase in insulin concentrations (second phase). The increment from basal to peak insulin release (0-2 min) was independent of glucose, but the first phase was maintained for longer and the second phase was greater at the highest concentration of glucose (12.5 mM). BTS 67 582 also extended the first-phase insulin response to a standard intravenous glucose challenge and enhanced the rate of glucose disappearance by approximately 12%. Thus BTS 67 582 causes biphasic stimulation of insulin release and augments the insulin-releasing effect of glucose.

  7. First calorimetric determination of heat of extraction of 248Cm in a bi-phasic system

    International Nuclear Information System (INIS)

    Martin, Leigh R.; Zalupski, Peter R.

    2011-01-01

    This report presents a summary of the work performed to meet FCR and D level 2 milestone M21SW050201, 'Complete the first calorimetric determination of heat of extraction of 248Cm in a bi-phasic system'. This work was carried out under the auspices of the Thermodynamics and Kinetics FCR and D work package. To complement previous work undertaken under this work package we have extended out heat of extraction studies by di-2-ethyl-hexyl-phosphoric acid to curium. This report also details the heat of extraction of samarium in the same system. This work was performed to not only test the methodology but also to check for consistency with the heats of extraction obtained with those in the prior literature. The heat of extraction for samarium that was obtained in this study was -9.6 kJ mol-1, which is in reasonable agreement with the previously obtained value of -10.9 kJ mol-1. The curium heat of extraction was performed under two sets of conditions and the obtained heats of extraction were in reasonable agreement with each other at -16.0 ± 1.1 and -16.8 ± 1.5 kJ mol-1.

  8. Biphasic Fluence-Response Curves for Phytochrome-Mediated Kalanchoë Seed Germination 1

    Science.gov (United States)

    Rethy, Roger; Dedonder, Andrée; De Petter, Edwin; Van Wiemeersch, Luc; Fredericq, Henri; De Greef, Jan; Steyaert, Herman; Stevens, Hilde

    1987-01-01

    The fluence-response curves for the effect of two red pulses separated by 24 hours on the germination of Kalanchoe blossfeldiana Poelln. cv Vesuv seeds, incubated on gibberellic acid (GA3) are biphasic for suboptimal concentrations. The response in the low fluence range corresponds with a classical red/far-red reversible phytochrome mediated reaction. GA3 induces an additional response in the very low fluence range, which is also phytochrome mediated. The sensitivity to phytochrome-far-red absorbing form (Pfr), however, is increased about 20,000-fold, so that even far-red fluences become saturating. Both in the very low and low fluence response range, the maximal responses induced by saturating fluences are modulated by the GA3 concentration. GA3 having no direct influence on the phytochrome phototransformations, alters the Pfr requirement and determines the responding seed population fraction in the very low and low fluence range. The effet of GA3 appears to be on the transduction chain of the phytochrome signal. PMID:16665187

  9. Biphasic effect of alcohol intake on the development of fatty liver disease.

    Science.gov (United States)

    Takahashi, Hirokazu; Ono, Masafumi; Hyogo, Hideyuki; Tsuji, Chika; Kitajima, Yoichiro; Ono, Naofumi; Eguchi, Takahisa; Fujimoto, Kazuma; Chayama, Kazuaki; Saibara, Toshiji; Anzai, Keizo; Eguchi, Yuichiro

    2015-11-01

    Fatty liver is an important clinical feature not only in alcoholic and non-alcoholic fatty liver diseases, but in other chronic liver diseases as well. Our aim was to elucidate the effect and relationship between habitual alcohol intake and obesity in the development of fatty liver disease. We enrolled 8,029 subjects undergoing abdominal ultrasonography with general medical examinations, and analyzed the factors associated with fatty liver based on daily alcohol intake, body mass index (BMI), and waist circumference. For fatty liver, BMI, waist circumference, total cholesterol, triglycerides, and fasting plasma glucose were significant and independent risk factors. Heavy alcohol intake (50 g/day) was a significant risk factor for fatty liver in women (odds ratio [OR], 3.35). Analysis based on the presence or absence of obesity revealed that moderate alcohol intake was a significant negative risk factor for fatty liver in both male and female obese (BMI ≥25 kg/m(2)) subjects (OR, 0.74 for non-obese and 0.39 for obese patients, respectively). Heavy alcohol intake was also a significant negative risk factor in obese males (0.62). In contrast, heavy alcohol intake was a risk factor in non-obese males (OR, 1.29) and in all females (OR, 2.22 for non-obese and 6.6 for obese patients, respectively). The influence of alcohol intake on fatty liver differed depending on the level of alcohol consumption, gender, and the presence of obesity, and showed biphasic effects.

  10. Study on biphasic material model and mechanical analysis of knee joint cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Nakatani, A; Sakashita, A [Department of Adaptive Machine Systems, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)], E-mail: nakatani@ams.eng.osaka-u.ac.jp

    2008-02-15

    A material model of articular cartilage is formulated, and fundamental problems are analyzed. The soft tissue is assumed to comprise two phases: solid and fluid. The biphasic theory proposed by Spilker and Suh (1990) to deal with such materials is reviewed, and some new additional analyses are carried out on the basis of this theory. Assuming the elasticity for the solid phase and introducing the pressure, which is defined by the product of the volume change and penalty coefficient, it is shown that the viscoelastic property of the soft tissue can be reproduced. A preferable solution is obtained for the solid phase by using the reduction integral, even if a high-order interpolation function is used. However, the high-order element cannot satisfactorily capture the velocity distribution of fluids. The pressure distribution is studied by assuming the change in the surface characteristics of the cartilage tissue with the progress of osteoarthritis. The pressure is strongly related to the lubrication conditions, i.e., perfect lubrication, perfect adhesion, and partial adhesion.

  11. Ectopic bone formation in bone marrow stem cell seeded calcium phosphate scaffolds as compared to autograft and (cell seeded allograft

    Directory of Open Access Journals (Sweden)

    J O Eniwumide

    2007-08-01

    Full Text Available Improvements to current therapeutic strategies are needed for the treatment of skeletal defects. Bone tissue engineering offers potential advantages to these strategies. In this study, ectopic bone formation in a range of scaffolds was assessed. Vital autograft and devitalised allograft served as controls and the experimental groups comprised autologous bone marrow derived stem cell seeded allograft, biphasic calcium phosphate (BCP and tricalcium phosphate (TCP, respectively. All implants were implanted in the back muscle of adult Dutch milk goats for 12 weeks. Micro-computed tomography (µCT analysis and histomorphometry was performed to evaluate and quantify ectopic bone formation. In good agreement, both µCT and histomorphometric analysis demonstrated a significant increase in bone formation by cell-seeded calcium phosphate scaffolds as compared to the autograft, allograft and cell-seeded allograft implants. An extensive resorption of the autograft, allograft and cell-seeded allograft implants was observed by histology and confirmed by histomorphometry. Cell-seeded TCP implants also showed distinct signs of degradation with histomorphometry and µCT, while the degradation of the cell-seeded BCP implants was negligible. These results indicate that cell-seeded calcium phosphate scaffolds are superior to autograft, allograft or cell-seeded allograft in terms of bone formation at ectopic implantation sites. In addition, the usefulness of µCT for the efficient and non-destructive analysis of mineralised bone and calcium phosphate scaffold was demonstrated.

  12. Calcium and Calcium Supplements: Achieving the Right Balance

    Science.gov (United States)

    ... may have on heart attack risk. A similar controversy surrounds calcium and prostate cancer. Some studies have ... your agreement to the Terms and Conditions and Privacy Policy linked below. Terms and Conditions Privacy Policy ...

  13. Calcium signals in olfactory neurons.

    Science.gov (United States)

    Tareilus, E; Noé, J; Breer, H

    1995-11-09

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness.

  14. Biological Assessment of a Calcium Silicate Incorporated Hydroxyapatite-Gelatin Nanocomposite: A Comparison to Decellularized Bone Matrix

    Directory of Open Access Journals (Sweden)

    Dong Joon Lee

    2014-01-01

    Full Text Available Our laboratory utilized biomimicry to develop a synthetic bone scaffold based on hydroxyapatite-gelatin-calcium silicate (HGCS. Here, we evaluated the potential of HGCS scaffold in bone formation in vivo using the rat calvarial critical-sized defect (CSD. Twelve Sprague-Dawley rats were randomized to four groups: control (defect only, decellularized bone matrix (DECBM, and HGCS with and without multipotent adult progenitor cells (MAPCs. DECBM was prepared by removing all the cells using SDS and NH4OH. After 12 weeks, the CSD specimens were harvested to evaluate radiographical, histological, and histomorphometrical outcomes. The in vitro osteogenic effects of the materials were studied by focal adhesion, MTS, and alizarin red. Micro-CT analysis indicated that the DECBM and the HGCS scaffold groups developed greater radiopaque areas than the other groups. Bone regeneration, assessed using histological analysis and fluorochrome labeling, was the highest in the HGCS scaffold seeded with MAPCs. The DECBM group showed limited osteoinductivity, causing a gap between the implant and host tissue. The group grafted with HGCS+MAPCs resulting in twice as much new bone formation seems to indicate a role for effective bone regeneration. In conclusion, the novel HGCS scaffold could improve bone regeneration and is a promising carrier for stem cell-mediated bone regeneration.

  15. Enhanced healing of rabbit segmental radius defects with surface-coated calcium phosphate cement/bone morphogenetic protein-2 scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yi; Hou, Juan; Yin, ManLi [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Wang, Jing, E-mail: biomatwj@163.com [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Liu, ChangSheng, E-mail: csliu@sh163.net [Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237 (China); Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China)

    2014-11-01

    Large osseous defects remain a difficult clinical problem in orthopedic surgery owing to the limited effective therapeutic options, and bone morphogenetic protein-2 (BMP-2) is useful for its potent osteoinductive properties in bone regeneration. Here we build a strategy to achieve prolonged duration time and help inducting new bone formation by using water-soluble polymers as a protective film. In this study, calcium phosphate cement (CPC) scaffolds were prepared as the matrix and combined with sodium carboxymethyl cellulose (CMC-Na), hydroxypropylmethyl cellulose (HPMC), and polyvinyl alcohol (PVA) respectively to protect from the digestion of rhBMP-2. After being implanted in the mouse thigh muscles, the surface-modified composite scaffolds evidently induced ectopic bone formation. In addition, we further evaluated the in vivo effects of surface-modified scaffolds in a rabbit radius critical defect by radiography, three dimensional micro-computed tomographic (μCT) imaging, synchrotron radiation-based micro-computed tomographic (SRμCT) imaging, histological analysis, and biomechanical measurement. The HPMC-modified CPC scaffold was regarded as the best combination for segmental bone regeneration in rabbit radius. - Highlights: • A simple surface-coating method was used to fabricate composite scaffolds. • Growth factor was protected from rapid depletion via superficial coating. • Significant promotion of bone regeneration was achieved. • HPMC-modification displayed optimal effect of bone regeneration.

  16. Development of an Injectable Calcium Phosphate/Hyaluronic Acid Microparticles System for Platelet Lysate Sustained Delivery Aiming Bone Regeneration.

    Science.gov (United States)

    Babo, Pedro S; Santo, Vítor E; Gomes, Manuela E; Reis, Rui L

    2016-11-01

    Despite the biocompatibility and osteoinductive properties of calcium phosphate (CaP) cements their low biodegradability hampers full bone regeneration. Herein the incorporation of CaP cement with hyaluronic acid (HAc) microparticles loaded with platelet lysate (PL) to improve the degradability and biological performance of the cements is proposed. Cement formulations incorporating increasing weight ratios of either empty HAc microparticles or microparticles loaded with PL (10 and 20 wt%) are developed as well as cements directly incorporating PL. The direct incorporation of PL improves the mechanical properties of the plain cement, reaching values similar to native bone. Morphological analysis shows homogeneous particle distribution and high interconnectivity between the HAc microparticles. The cements incorporating PL (with or without the HAc microparticles) present a sustained release of PL proteins for up to 8 d. The sustained release of PL modulates the expression of osteogenic markers in seeded human adipose tissue derived stem cells, thus suggesting the stimulatory role of this hybrid system toward osteogenic commitment and bone regeneration applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. The Influence of Electrolytic Concentration on the Electrochemical Deposition of Calcium Phosphate Coating on a Direct Laser Metal Forming Surface

    Directory of Open Access Journals (Sweden)

    Qianyue Sun

    2017-01-01

    Full Text Available A calcium phosphate (CaP coating on titanium surface enhances its biocompatibility, thus facilitating osteoconduction and osteoinduction with the inorganic phase of the human bone. Electrochemical deposition has been suggested as an effective means of fabricating CaP coatings on porous surface. The purpose of this study was to develop CaP coatings on a direct laser metal forming implant using electrochemical deposition and to investigate the effect of electrolytic concentration on the coating’s morphology and structure by X-ray diffraction, scanning electron microscopy, water contact angle analysis, and Fourier transform infrared spectroscopy. In group 10−2, coatings were rich in dicalcium phosphate, characterized to be thick, layered, and disordered plates. In contrast, in groups 10−3 and 10−4, the relatively thin and well-ordered coatings predominantly consisted of granular hydroxyapatite. Further, the hydrophilicity and cell affinity were improved as electrolytic concentration increased. In particular, the cells cultured in group 10−3 appeared to have spindle morphology with thick pseudopodia on CaP coatings; these spindles and pseudopodia strongly adhered to the rough and porous surface. By analyzing and evaluating the surface properties, we provided further knowledge on the electrolytic concentration effect, which will be critical for improving CaP coated Ti implants in the future.

  18. Why Calcium? How Calcium Became the Best Communicator*

    OpenAIRE

    Carafoli, Ernesto; Krebs, Joachim

    2016-01-01

    Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations,...

  19. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    International Nuclear Information System (INIS)

    Christensen, Hilbert

    1962-12-01

    By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca 9 Sr(PO 4 ) 6 (OH) 2 - CaSr 9 (PO 4 ) 6 (OH) 2 . The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice

  20. Influence of dietary calcium on bone calcium utilization

    International Nuclear Information System (INIS)

    Farmer, M.; Roland, D.A. Sr.; Clark, A.J.

    1986-01-01

    In Experiment 1, 10 microCi 45 Ca/day were administered to 125 hens for 10 days. Hens were then allocated to five treatments with calcium levels ranging from .08 to 3.75% of the diet. In Experiment 2, hens with morning oviposition times were randomly allocated to 11 treatments that were periods of time postoviposition ranging from 6 hr to 24 hr, in 2-hr increments (Experiment 2). At the end of each 2-hr period, eggs from 25 hens were removed from the uterus. The 18-, 20-, and 22-hr treatments were replicated three times. In Experiment 3, hens were fed either ad libitum or feed was withheld the last 5 or 6 hr before oviposition. In Experiment 4, hens were fed 10 microCi of 45 Ca for 15 days to label skeletal calcium. Hens were divided into two groups and fed a .08 or 3.75% calcium diet for 2 days. On the second day, 25 hens fed the 3.75% calcium diet were intubated with 7 g of the same diet containing .5 g calcium at 1700, 2100, 0100, 0500, and 0700 hr. The measurements used were egg weight, shell weight, and 45 Ca content of the egg shell. Results indicated a significant linear or quadratic regression of dietary calcium levels on 45 Ca accumulation in eggshells and eggshell weight (Experiment 1). As the calcium level of the diet increased, eggshell weight increased and 45 Ca recovery decreased. Utilization of skeletal calcium for shell formation ranged from 28 to 96%. In Experiment 2, the rate of shell calcification was not constant throughout the calcification process but varied significantly

  1. 21 CFR 172.410 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely...

  2. A Crash Course in Calcium Channels.

    Science.gov (United States)

    Zamponi, Gerald W

    2017-12-20

    Much progress has been made in understanding the molecular physiology and pharmacology of calcium channels. Recently, there have been tremendous advances in learning about calcium channel structure and function through crystallography and cryo-electron microscopy studies. Here, I will give an overview of our knowledge about calcium channels, and highlight two recent studies that give important insights into calcium channel structure.

  3. Calcium-sensing beyond neurotransmitters

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Han, Weiping

    2009-01-01

    Neurotransmitters, neuropeptides and hormones are released through the regulated exocytosis of SVs (synaptic vesicles) and LDCVs (large dense-core vesicles), a process that is controlled by calcium. Synaptotagmins are a family of type 1 membrane proteins that share a common domain structure. Most....... Also, we discuss potential roles of synaptotagmins in non-traditional endocrine systems....... synaptotagmins are located in brain and endocrine cells, and some of these synaptotagmins bind to phospholipids and calcium at levels that trigger regulated exocytosis of SVs and LDCVs. This led to the proposed synaptotagmin-calcium-sensor paradigm, that is, members of the synaptotagmin family function...... as calcium sensors for the regulated exocytosis of neurotransmitters, neuropeptides and hormones. Here, we provide an overview of the synaptotagmin family, and review the recent mouse genetic studies aimed at understanding the functions of synaptotagmins in neurotransmission and endocrine-hormone secretion...

  4. Calcium phosphates for biomedical applications

    Directory of Open Access Journals (Sweden)

    Maria Canillas

    2017-05-01

    Full Text Available The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies.

  5. Functions of vitamin D / Calcium

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Excitation-contraction coupling,. Cardiac functions. Hormonal secretion. Control of enzymatic reactions. Mitotic division. Maintenance of cell integrity. Ciliary motility. Notes: Calcium is a vital second messenger.

  6. Calcium signals in planetary embryos

    Science.gov (United States)

    Morbidelli, Alessandro

    2018-03-01

    The calcium-isotope composition of planetary bodies in the inner Solar System correlates with the masses of such objects. This finding could have implications for our understanding of how the Solar System formed.

  7. Calcium homeostasis in diabetes mellitus.

    Science.gov (United States)

    Ahn, Changhwan; Kang, Ji-Houn; Jeung, Eui-Bae

    2017-09-30

    Diabetes mellitus (DM) is becoming a lifestyle-related pandemic disease. Diabetic patients frequently develop electrolyte disorders, especially diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. Such patients show characteristic potassium, magnesium, phosphate, and calcium depletion. In this review, we discuss a homeostatic mechanism that links calcium and DM. We also provide a synthesis of the evidence in favor or against this linking mechanism by presenting recent clinical indications, mainly from veterinary research. There are consistent results supporting the use of calcium and vitamin D supplementation to reduce the risk of DM. Clinical trials support a marginal reduction in circulating lipids, and some meta-analyses support an increase in insulin sensitivity, following vitamin D supplementation. This review provides an overview of the calcium and vitamin D disturbances occurring in DM and describes the underlying mechanisms. Such elucidation will help indicate potential pathophysiology-based precautionary and therapeutic approaches and contribute to lowering the incidence of DM.

  8. Calcium phosphates for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Canillas, M.; Pena, P.; Aza, A.H. de; Rodriguez, M.A.

    2017-07-01

    The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies. (Author)

  9. Calcium signaling in liver.

    Science.gov (United States)

    Gaspers, Lawrence D; Thomas, Andrew P

    2005-01-01

    In hepatocytes, hormones linked to the formation of the second messenger inositol 1,4,5-trisphosphate (InsP3) evoke transient increases or spikes in cytosolic free calcium ([Ca2+]i), that increase in frequency with the agonist concentration. These oscillatory Ca2+ signals are thought to transmit the information encoded in the extracellular stimulus to down-stream Ca2+-sensitive metabolic processes. We have utilized both confocal and wide field fluorescence microscopy techniques to study the InsP3-dependent signaling pathway at the cellular and subcellular levels in the intact perfused liver. Typically InsP3-dependent [Ca2+]i spikes manifest as Ca2+ waves that propagate throughout the entire cytoplasm and nucleus, and in the intact liver these [Ca2+]i increases are conveyed through gap junctions to encompass entire lobular units. The translobular movement of Ca2+ provides a means to coordinate the function of metabolic zones of the lobule and thus, liver function. In this article, we describe the characteristics of agonist-evoked [Ca2+]i signals in the liver and discuss possible mechanisms to explain the propagation of intercellular Ca2+ waves in the intact organ.

  10. Effects of diphosphonate on kidney calcium content and duodenal absorption of 45calcium

    International Nuclear Information System (INIS)

    Goulding, A.; Cameron, V.

    1978-01-01

    In rats the relationships between EHDP-induced changes in serum calcium concentration, kidney calcium content and duodenal transport of 45 calcium were studied. Body weights and kidney weights were similar in all groups. EHDP administration was associated with an increase in serum calcium concentration and kidney calcium content, and a decrease in duodenal 45 calcium transport. In the EHDP-treated rats, there was a significant negative correlation between kidney calcium concentration and duodenal 45 calcium transport but no correlation between either kidney calcium content and serum calcium concentration (r = 0.116) or between serum calcium concentration and duodenal 45 calcium transport (r = 0.02). Further experiments will be needed to determine whether the demonstrated increase in kidney calcium content induced by EHDP administration was the cause of, or was secondary to, inhibition of 1, 25(OH) 2 D 3 synthesis. (orig./AJ) [de

  11. Nano clay-enhanced calcium phosphate cements and hydrogels for biomedical applications

    Science.gov (United States)

    Jammalamadaka, Udayabhanu

    Biomaterials are used as templates for drug delivery, scaffolds in tissue engineering, grafts in surgeries, and support for tissue regeneration. Novel biomaterial composites are needed to meet multifaceted requirements of compatibility, ease of fabrication and controlled drug delivery. Currently used biomaterials in orthopedics surgeries suffer limitations in toxicity and preventing infections. Polymethyl methacrylate (PMMA) used as bone cement suffers from limitations of thermal necrosis and monomer toxicity calls for development of better cementing biomaterials. A biodegradable/bioresorbable cement with good mechanical properties is needed to address this short coming. Metal implants used in fixing fractures or total joint replacement needs improvements in preventing biofilm formation and better tissue integration. This research addressed the above mentioned research gaps by formulating novel biomaterial composites. Calcium phosphate cements are the alternative bone cements that are bioresorbable and promote tissue integration. These cements lack sufficient mechanical strengths to be used in load bearing sites. The addition of nanoparticles is hypothesized to improve the mechanical properties without inducing toxicity to the tissue. This hypothesis was tested by evaluating compression and flexural strengths in addition to cytocompatibility tests. Results indicate that addition of nano-clay particles (halloysites nanotubes) improved the compressive strength and osteoinductive properties of calcium phosphate cements. To address the research need of preventing implant failure due to infection and aseptic loosening, novel coatings are needed. Hydrogels are well establish for their ability to mimic in vivo environment, promote cell viability and as drug delivery vehicles. Use of composites of hydrogels and drug-loaded nanoparticles to prevent infection was evaluated. Cytocompatibility results indicate good cell viability. Antibacterial results show sustained release

  12. Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Vuk Uskoković

    2016-06-01

    Full Text Available Socially responsible technologies are designed while taking into consideration the socioeconomic, geopolitical and environmental limitations of regions in which they will be implemented. In the medical context, this involves making therapeutic platforms more accessible and affordable to patients in poor regions of the world wherein a given disease is endemic. This often necessitates going against the reigning trend of making therapeutic nanoparticles ever more structurally complex and expensive. However, studies aimed at simplifying materials and formulations while maintaining the functionality and therapeutic response of their more complex counterparts seldom provoke a significant interest in the scientific community. In this review we demonstrate that such compositional simplifications are meaningful when it comes to the design of a solution for osteomyelitis, a disease that is in its natural, non-postoperative form particularly prevalent in the underdeveloped parts of the world wherein poverty, poor sanitary conditions, and chronically compromised defense lines of the immune system are the norm. We show that calcium phosphate nanoparticles, which are inexpensive to make, could be chemically designed to possess the same functionality as a hypothetic mixture additionally composed of: (a a bone growth factor; (b an antibiotic for prophylactic or anti-infective purposes; (c a bisphosphonate as an antiresorptive compound; (d a viral vector to enable the intracellular delivery of therapeutics; (e a luminescent dye; (f a radiographic component; (g an imaging contrast agent; (h a magnetic domain; and (i polymers as viscous components enabling the injectability of the material and acting as carriers for the sustained release of a drug. In particular, calcium phosphates could: (a produce tunable drug release profiles; (b take the form of viscous and injectable, self-setting pastes; (c be naturally osteo-inductive and inhibitory for osteoclastogenesis

  13. Research of calcium oxide hydration in calcium nitrate solutions

    Directory of Open Access Journals (Sweden)

    M.A. Oliynyk

    2016-09-01

    Full Text Available Mineral fertilizers are one of the important factors of agriculture intensification and increasing of food products quantity. The volume of fertilizers production and its domestic consumption in Ukraine indicate that nitrogen fertilizer using only comes nearer to the required number of science-based. One of the most widespread artificial fertilizers is the calcium nitrate. Aim: The aim is to study and theoretically substantiate the processes occurring in the preparation of suspensions of calcium hydroxide Са(ОН2 in solution of calcium nitrate Ca(NО32. Materials and Methods: The technical calcium oxide (quicklime DSTU BV.2.7-90-99, solutions of calcium nitrate of 15, 20, 25, 30, 35 and 40% Ca(NО32 concentrations were used in the work. The content of lime in the preparation of a suspension in the solution changed (in terms of calcium oxide CaO from 150 g/dm3 to the maximum possible. Each of these solutions saturated at 40°С in lime to maximum concentration. Suitable for use in these experiments and in the technology of calcium nitrate obtaining are considered the solutions (suspensions that within 12 hours did not lose their mobility (transportability. Results: The experimental results show that increasing of the concentration of calcium nitrate in solution within the range 15...40%, the amount of lime that you can put into the solution without loss of transportability decreases. Further increasing of lime quantity in solutions concentrations causes to its solidifying, loss of mobility (transportability. Calculations showed that in the presence of calcium nitrate the solubility of Са(ОН2 is reduced nearly by order that can lead to the formation of calcium oxide CaO the solid phase Са(ОН2 on the surface, which also can form hydrogen bonds with the components of the solution. As the probability of formation of hydrogen bonds in solutions is high, there is a possibility of formation of clusters.

  14. Time course of air hunger mirrors the biphasic ventilatory response to hypoxia.

    Science.gov (United States)

    Moosavi, S H; Banzett, R B; Butler, J P

    2004-12-01

    Determining response dynamics of hypoxic air hunger may provide information of use in clinical practice and will improve understanding of basic dyspnea mechanisms. It is hypothesized that air hunger arises from projection of reflex brain stem ventilatory drive ("corollary discharge") to forebrain centers. If perceptual response dynamics are unmodified by events between brain stem and cortical awareness, this hypothesis predicts that air hunger will exactly track ventilatory response. Thus, during sustained hypoxia, initial increase in air hunger would be followed by a progressive decline reflecting biphasic reflex ventilatory drive. To test this prediction, we applied a sharp-onset 20-min step of normocapnic hypoxia and compared dynamic response characteristics of air hunger with that of ventilation in 10 healthy subjects. Air hunger was measured during mechanical ventilation (minute ventilation = 9 +/- 1.4 l/min; end-tidal Pco(2) = 37 +/- 2 Torr; end-tidal Po(2) = 45 +/- 7 Torr); ventilatory response was measured during separate free-breathing trials in the same subjects. Discomfort caused by "urge to breathe" was rated every 30 s on a visual analog scale. Both ventilatory and air hunger responses were modeled as delayed double exponentials corresponding to a simple linear first-order response but with a separate first-order adaptation. These models provided adequate fits to both ventilatory and air hunger data (r(2) = 0.88 and 0.66). Mean time constant and time-to-peak response for the average perceptual response (0.36 min(-1) and 3.3 min, respectively) closely matched corresponding values for the average ventilatory response (0.39 min(-1) and 3.1 min). Air hunger response to sustained hypoxia tracked ventilatory drive with a delay of approximately 30 s. Our data provide further support for the corollary discharge hypothesis for air hunger.

  15. Microculture in biphasic medium with silicone-coated slides for isolation of mycobacteria.

    Science.gov (United States)

    Shibayama, H; Galván, F J; Contreras, C

    1996-09-01

    The study reported here, seeking to develop a simple, practical, sensitive, and inexpensive technique for microbial diagnosis of tuberculosis, used a combination of biphasic media and microculture techniques to augment the sensitivity of traditional culture methods. A total of 540 sputum samples (5 mL each) were obtained from 180 patients with suspected tuberculosis in Mexico City. These samples were treated with Hanks reagent, neutralized with 25% HCl, and centrifuged. In each case the resulting residue was combined with liquid media (Sula medium or a phosphate-buffered control solution) and was inoculated into a bottle containing a solid medium (Löwenstein-Jensen-Holm or Middlebrook). A silicone-coated slide appropriate for culture of hydrophobic mycobacteria was inserted in each bottle, and the cultures (examined weekly) were incubated at 37 degrees C until the first macroscopic bacterial growth was detected or for up to eight weeks if none was detected. When such growth was detected, or at the end of eight weeks, each slide was withdrawn from the bottle, sterilized, stained by Kinyoun's method, and examined microscopically. Following 2-4 weeks of incubation, macroscopic bacterial growth was detected in 71 bottles and was confirmed by microscopic examination of the corresponding slides. No macroscopic bacterial growth was found in any of the remaining 469 bottles, but microscopic growth was observed on 77 of the slides examined after eight weeks. The authors conclude that this method represents a noteworthy improvement over standard culture methods in terms of bacterial isolation and suggest that its case, economy, and practicality make it suitable for application in developing countries.

  16. Early Peritoneal Immune Response during Echinococcus granulosus Establishment Displays a Biphasic Behavior

    Science.gov (United States)

    Mourglia-Ettlin, Gustavo; Marqués, Juan Martín; Chabalgoity, José Alejandro; Dematteis, Sylvia

    2011-01-01

    Background Cystic echinococcosis is a worldwide distributed helminth zoonosis caused by the larval stage of Echinococcus granulosus. Human secondary cystic echinococcosis is caused by dissemination of protoscoleces after accidental rupture of fertile cysts and is due to protoscoleces ability to develop into new metacestodes. In the experimental model of secondary cystic echinococcosis mice react against protoscoleces producing inefficient immune responses, allowing parasites to develop into cysts. Although the chronic phase of infection has been analyzed in depth, early immune responses at the site of infection establishment, e.g., peritoneal cavity, have not been well studied. Because during early stages of infection parasites are thought to be more susceptible to immune attack, this work focused on the study of cellular and molecular events triggered early in the peritoneal cavity of infected mice. Principal Findings Data obtained showed disparate behaviors among subpopulations within the peritoneal lymphoid compartment. Regarding B cells, there is an active molecular process of plasma cell differentiation accompanied by significant local production of specific IgM and IgG2b antibodies. In addition, peritoneal NK cells showed a rapid increase with a significant percentage of activated cells. Peritoneal T cells showed a substantial increase, with predominance in CD4+ T lymphocytes. There was also a local increase in Treg cells. Finally, cytokine response showed local biphasic kinetics: an early predominant induction of Th1-type cytokines (IFN-γ, IL-2 and IL-15), followed by a shift toward a Th2-type profile (IL-4, IL-5, IL-6, IL-10 and IL-13). Conclusions Results reported here open new ways to investigate the involvement of immune effectors players in E. granulosus establishment, and also in the sequential promotion of Th1- toward Th2-type responses in experimental secondary cystic echinococcosis. These data would be relevant for designing rational therapies

  17. Volume fraction prediction in biphasic flow using nuclear technique and artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Cesar M.; Brandao, Luis E.B., E-mail: otero@ien.gov.br, E-mail: brandao@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The volume fraction is one of the most important parameters used to characterize air-liquid two-phase flows. It is a physical value to determine other parameters, such as the phase's densities and to determine the flow rate of each phase. These parameters are important to predict the flow pattern and to determine a mathematical model for the system. To study, for example, heat transfer and pressure drop. This work presents a methodology for volume fractions prediction in water-gas stratified flow regime using the nuclear technique and artificial intelligence. The volume fractions calculate in biphasic flow systems is complex and the analysis by means of analytical equations becomes very difficult. The approach is based on gamma-ray pulse height distributions pattern recognition by means of the artificial neural network. The detection system uses appropriate broad beam geometry, comprised of a ({sup 137}Cs) energy gamma-ray source and a NaI(Tl) scintillation detector in order measure transmitted beam whose the counts rates are influenced by the phases composition. These distributions are directly used by the network without any parameterization of the measured signal. The ideal and static theoretical models for stratified regime have been developed using MCNP-X code, which was used to provide training, test and validation data for the network. The detector also was modeled with this code and the results were compared to experimental photopeak efficiency measurements of radiation sources. The proposed network could obtain with satisfactory prediction of the volume fraction in water-gas system, demonstrating to be a promising approach for this purpose. (author)

  18. Volume fraction prediction in biphasic flow using nuclear technique and artificial neural network

    International Nuclear Information System (INIS)

    Salgado, Cesar M.; Brandao, Luis E.B.

    2015-01-01

    The volume fraction is one of the most important parameters used to characterize air-liquid two-phase flows. It is a physical value to determine other parameters, such as the phase's densities and to determine the flow rate of each phase. These parameters are important to predict the flow pattern and to determine a mathematical model for the system. To study, for example, heat transfer and pressure drop. This work presents a methodology for volume fractions prediction in water-gas stratified flow regime using the nuclear technique and artificial intelligence. The volume fractions calculate in biphasic flow systems is complex and the analysis by means of analytical equations becomes very difficult. The approach is based on gamma-ray pulse height distributions pattern recognition by means of the artificial neural network. The detection system uses appropriate broad beam geometry, comprised of a ( 137 Cs) energy gamma-ray source and a NaI(Tl) scintillation detector in order measure transmitted beam whose the counts rates are influenced by the phases composition. These distributions are directly used by the network without any parameterization of the measured signal. The ideal and static theoretical models for stratified regime have been developed using MCNP-X code, which was used to provide training, test and validation data for the network. The detector also was modeled with this code and the results were compared to experimental photopeak efficiency measurements of radiation sources. The proposed network could obtain with satisfactory prediction of the volume fraction in water-gas system, demonstrating to be a promising approach for this purpose. (author)

  19. Low cadmium exposure triggers a biphasic oxidative stress response in mice kidneys

    International Nuclear Information System (INIS)

    Thijssen, Sandy; Cuypers, Ann; Maringwa, John; Smeets, Karen; Horemans, Nele; Lambrichts, Ivo; Van Kerkhove, Emmy

    2007-01-01

    Oxidative stress is believed to participate in the early processes of cadmium (Cd)-induced proximal tubular kidney damage. Mice were chronically exposed up to 23 weeks to low Cd concentrations (10 and 100 mg CdCl 2 /l) via the drinking water. Pro- and antioxidant gene expression levels, glutathione, ascorbate and lipid peroxidation levels were measured. Our study provided evidence for an early and a late stress response in the kidney. Metallothioneins were upregulated from 1 week of exposure on and they stayed important during the whole exposure period. After 8 weeks the expression of Bcl2 (anti-apoptotic), Prdx2 and cytosolic superoxide dismutase (Sod1) was reduced in the group exposed to 100 mg CdCl 2 /l, which might indicate a response to Cd-stress. However glutathione, ascorbate and lipid peroxidation levels did not significantly change, and the overall redox balance remained stable. Stable Sod2 transcriptional levels suggested that an increased formation of superoxide anions, which can arise upon Cd-induced mitochondrial free radical generation, was not appearing. A second defence activation was observed after 23 weeks: i.e. an increase of catalase (Cat), glutathione peroxidase 4 (Gpx4) and heme oxygenase 1 (Hmox1), together with NADPH oxidase 4 (Nox4), of which the role has not been studied yet in Cd nephrotoxicity. These findings were in contrast with previous studies, where Cd-induced oxidative stress was detrimental when high Cd concentrations were applied. In conclusion our study provided evidence that a chronic exposure to low Cd concentrations triggered a biphasic defence activation in the kidney that might lead to adaptation and survival

  20. Electrochemical assessment of water|ionic liquid biphasic systems towards cesium extraction from nuclear waste.

    Science.gov (United States)

    Stockmann, T Jane; Zhang, Jing; Montgomery, Anne-Marie; Ding, Zhifeng

    2014-04-22

    A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P66614(+)) and tetrakis(pentafluorophenyl)borate anion (TB(-)) was employed within a water|P66614TB (w|P66614TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. (137)Cs is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is therefore of considerable importance. The extraction was facilitated by the ligand octyl(phenyl)-N,N'-diisobutylcarbamoylphosphine oxide (CMPO) used in TRans-Uranium EXtraction processes and investigated through well established liquid|liquid electrochemistry. This study gave access to the metal ion to ligand (1:n) stoichiometry and overall complexation constant, β, of the interfacial complexation reaction which were determined to be 1:3 and 1.6×10(11) at the w|P66614TB interface while the study at w|o elicited an n equal to 1 with β equal to 86.5. Through a straightforward relationship, these complexation constant values were converted to distribution coefficients, δ(α), with the ligand concentrations studied for comparison to other studies present in the literature; the w|o and w|IL systems gave δ(α) of 2 and 8.2×10(7), respectively, indicating a higher overall extraction efficiency for the latter. For the w|o system, the metal ion-ligand stoichiometries were confirmed through isotopic distribution analysis of mass spectra obtained by the direct injection of an emulsified water-organic solvent mixture into an electron spray ionization mass spectrometer. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Calcium Orthophosphate Cements and Concretes

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2009-03-01

    Full Text Available In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone, calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.

  2. MC3T3-E1 proliferation and differentiation on biphasic mixtures of Mg substituted β-tricalcium phosphate and amorphous calcium phosphate

    International Nuclear Information System (INIS)

    Singh, Satish S.; Roy, Abhijit; Lee, Boeun E.; Banerjee, Ipsita; Kumta, Prashant N.

    2014-01-01

    A low temperature aqueous approach was used to synthesize nanocrystalline, high surface area Mg 2+ substituted β-tricalcium phosphate (β-TCMP) to assess its potential use as a synthetic bone graft substitute. X-ray diffraction indicated that β-TCMP was the predominant crystalline phase formed. However, thermal analysis revealed the presence of a secondary amorphous phase which increased with increasing Mg 2+ concentration. Further analysis by Rietveld refinement indicated that the level of ionic substitution of Ca 2+ by Mg 2+ was significantly lower than the amount of Mg 2+ measured using elemental analysis, confirming the formation of a Mg 2+ rich secondary amorphous phase. MC3T3-E1 proliferation on substrates prepared using β-TCMP was assessed using the MTT assay. In comparison to commercially available β-TCP, increased proliferation was observed on samples prepared with 50% Mg, despite elevated Mg 2+ and PO 4 3− concentrations in culture media. Alkaline phosphatase (ALP) activity and qRT-PCR were used to study the effect of varying Mg 2+ substitution on osteogenic differentiation. Cells cultured on β-TCMP substrates prepared with increased Mg 2+ concentrations expressed significantly increased levels of ALP activity and osteogenic genes such as, osteocalcin, collagen-1, and Runx2, in comparison to those cultured on commercially available β-TCP

  3. Effect of different calcium phosphate scaffold ratios on odontogenic differentiation of human dental pulp cells

    Energy Technology Data Exchange (ETDEWEB)

    AbdulQader, Sarah Talib [School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Department of Pedodontic and Preventive Dentistry, College of Dentistry, University of Baghdad, Baghdad (Iraq); Kannan, Thirumulu Ponnuraj, E-mail: kannan@usm.my [School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Human Genome Centre, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Rahman, Ismail Ab [School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Ismail, Hanafi [School of Materials and Minerals Resource Engineering, Universiti Sains Malaysia, 14300 Penang (Malaysia); Mahmood, Zuliani [School of Dental Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

    2015-04-01

    Calcium phosphate (CaP) scaffolds have been widely and successfully used with osteoblast cells for bone tissue regeneration. However, it is necessary to investigate the effects of these scaffolds on odontoblast cells' proliferation and differentiation for dentin tissue regeneration. In this study, three different hydroxyapatite (HA) to beta tricalcium phosphate (β-TCP) ratios of biphasic calcium phosphate (BCP) scaffolds, BCP20, BCP50, and BCP80, with a mean pore size of 300 μm and 65% porosity were prepared from phosphoric acid (H{sub 2}PO{sub 4}) and calcium carbonate (CaCO{sub 3}) sintered at 1000 °C for 2 h. The extracts of these scaffolds were assessed with regard to cell viability and differentiation of odontoblasts. The high alkalinity, more calcium, and phosphate ions released that were exhibited by BCP20 decreased the viability of human dental pulp cells (HDPCs) as compared to BCP50 and BCP80. However, the cells cultured with BCP20 extract expressed high alkaline phosphatase activity and high expression level of bone sialoprotein (BSP), dental matrix protein-1 (DMP-1), and dentin sialophosphoprotein (DSPP) genes as compared to that cultured with BCP50 and BCP80 extracts. The results highlighted the effect of different scaffold ratios on the cell microenvironment and demonstrated that BCP20 scaffold can support HDPC differentiation for dentin tissue regeneration. - Highlights: • BCPs of different HA/β-TCP ratios influence cell microenvironment. • BCP20 decreases cell viability of HDPCs as compared to BCP50 and BCP80. • HDPCs cultured with BCP20 express highest ALP activity. • HDPCs cultured with BCP20 up-regulate BSP, DMP-1 and DSPP gene expressions. • BCP20 can support HDPC differentiation for dentin tissue regeneration.

  4. Effect of different calcium phosphate scaffold ratios on odontogenic differentiation of human dental pulp cells

    International Nuclear Information System (INIS)

    AbdulQader, Sarah Talib; Kannan, Thirumulu Ponnuraj; Rahman, Ismail Ab; Ismail, Hanafi; Mahmood, Zuliani

    2015-01-01

    Calcium phosphate (CaP) scaffolds have been widely and successfully used with osteoblast cells for bone tissue regeneration. However, it is necessary to investigate the effects of these scaffolds on odontoblast cells' proliferation and differentiation for dentin tissue regeneration. In this study, three different hydroxyapatite (HA) to beta tricalcium phosphate (β-TCP) ratios of biphasic calcium phosphate (BCP) scaffolds, BCP20, BCP50, and BCP80, with a mean pore size of 300 μm and 65% porosity were prepared from phosphoric acid (H 2 PO 4 ) and calcium carbonate (CaCO 3 ) sintered at 1000 °C for 2 h. The extracts of these scaffolds were assessed with regard to cell viability and differentiation of odontoblasts. The high alkalinity, more calcium, and phosphate ions released that were exhibited by BCP20 decreased the viability of human dental pulp cells (HDPCs) as compared to BCP50 and BCP80. However, the cells cultured with BCP20 extract expressed high alkaline phosphatase activity and high expression level of bone sialoprotein (BSP), dental matrix protein-1 (DMP-1), and dentin sialophosphoprotein (DSPP) genes as compared to that cultured with BCP50 and BCP80 extracts. The results highlighted the effect of different scaffold ratios on the cell microenvironment and demonstrated that BCP20 scaffold can support HDPC differentiation for dentin tissue regeneration. - Highlights: • BCPs of different HA/β-TCP ratios influence cell microenvironment. • BCP20 decreases cell viability of HDPCs as compared to BCP50 and BCP80. • HDPCs cultured with BCP20 express highest ALP activity. • HDPCs cultured with BCP20 up-regulate BSP, DMP-1 and DSPP gene expressions. • BCP20 can support HDPC differentiation for dentin tissue regeneration

  5. 21 CFR 184.1207 - Calcium lactate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium lactate. 184.1207 Section 184.1207 Food and... Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where x is any... calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of the Food Chemicals...

  6. Exercise enhance the ectopic bone formation of calcium phosphate biomaterials in muscles of mice.

    Science.gov (United States)

    Cheng, Lijia; Yan, Shuo; Zhu, Jiang; Cai, Peiling; Wang, Ting; Shi, Zheng

    2017-08-01

    To investigate whether exercise can enhance ectopic bone formation of calcium phosphate (Ca-P) biomaterials in muscles of mice. Firstly, ten transient receptor potential vanilloid subfamily member 1 (TRPV1) knockout mice (group KO) and ten C57BL/6 mice (group WT) were randomly chosen, 10μg Ca-P biomaterials were implanted into the thigh muscle pouch of each mouse which was far away from femur; after that, all animals were kept in open field for free exploration 5min, and the movement time and distance were automatically analyzed. Ten weeks later, the Ca-P samples were harvested for histological staining and immunochemistry. Secondly, the Ca-P biomaterials were implanted into the thigh muscle pouch of C57BL/6 mice the same as previous operation, and then randomly divided into two groups: running group and non-running group (n=10); in running group, all mice run 1h as a speed of 6m/h in a treadmill for 10weeks. Ten weeks later, the blood was collected to detect the interleukin-4 (IL-4) and IL-12 levels by enzyme linked immunosorbent assay (ELISA), and the samples were harvested for histological staining. In groups KO and WT, both the movement time and distance were significant higher in group KO than that in group WT (Pstronger athletic ability of mice, causing better osteoinductivity of Ca-P biomaterials both in TRPV1 -/- mice and running mice; according to this, we want to offer a proposal to patients who suffer from bone defects and artificial bone transplantation: do moderate exercise, don't convalesce all the time. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Why Calcium? How Calcium Became the Best Communicator*

    Science.gov (United States)

    Carafoli, Ernesto; Krebs, Joachim

    2016-01-01

    Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations, e.g. magnesium. Its free concentration within cells can thus be maintained at the very low levels demanded by the signaling function. A large cadre of proteins has evolved to bind or transport calcium. They all contribute to buffer it within cells, but a number of them also decode its message for the benefit of the target. The most important of these “calcium sensors” are the EF-hand proteins. Calcium is an ambivalent messenger. Although essential to the correct functioning of cell processes, if not carefully controlled spatially and temporally within cells, it generates variously severe cell dysfunctions, and even cell death. PMID:27462077

  8. Why Calcium? How Calcium Became the Best Communicator.

    Science.gov (United States)

    Carafoli, Ernesto; Krebs, Joachim

    2016-09-30

    Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations, e.g. magnesium. Its free concentration within cells can thus be maintained at the very low levels demanded by the signaling function. A large cadre of proteins has evolved to bind or transport calcium. They all contribute to buffer it within cells, but a number of them also decode its message for the benefit of the target. The most important of these "calcium sensors" are the EF-hand proteins. Calcium is an ambivalent messenger. Although essential to the correct functioning of cell processes, if not carefully controlled spatially and temporally within cells, it generates variously severe cell dysfunctions, and even cell death. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Bone regeneration in experimental animals using calcium phosphate cement combined with platelet growth factors and human growth hormone.

    Science.gov (United States)

    Emilov-Velev, K; Clemente-de-Arriba, C; Alobera-García, M Á; Moreno-Sansalvador, E M; Campo-Loarte, J

    2015-01-01

    Many substances (growth factors and hormones) have osteoinduction properties and when added to some osteoconduction biomaterial they accelerate bone neoformation properties. The materials included 15 New Zealand rabbits, calcium phosphate cement (Calcibon(®)), human growth hormone (GH), and plasma rich in platelets (PRP). Each animal was operated on in both proximal tibias and a critical size bone defect of 6mm of diameter was made. The animals were separated into the following study groups: Control (regeneration only by Calcibon®), PRP (regeneration by Calcibon® and PRP), GH (regeneration by Calcibon® and GH). All the animals were sacrificed at 28 days. An evaluation was made of the appearance of the proximal extreme of rabbit tibiae in all the animals, and to check the filling of the critical size defect. A histological assessment was made of the tissue response, the presence of new bone formation, and the appearance of the biomaterial. Morphometry was performed using the MIP 45 image analyser. ANOVA statistical analysis was performed using the Statgraphics software application. The macroscopic appearance of the critical defect was better in the PRP and the GH group than in the control group. Histologically greater new bone formation was found in the PRP and GH groups. No statistically significant differences were detected in the morphometric study between bone formation observed in the PRP group and the control group. Significant differences in increased bone formation were found in the GH group (p=0.03) compared to the other two groups. GH facilitates bone regeneration in critical defects filled with calcium phosphate cement in the time period studied in New Zealand rabbits. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

  10. Testosterone increases urinary calcium excretion and inhibits expression of renal calcium transport proteins.

    NARCIS (Netherlands)

    Hsu, Y.J.; Dimke, H.; Schoeber, J.P.H.; Hsu, S.C.; Lin, S.H.; Chu, P.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2010-01-01

    Although gender differences in the renal handling of calcium have been reported, the overall contribution of androgens to these differences remains uncertain. We determined here whether testosterone affects active renal calcium reabsorption by regulating calcium transport proteins. Male mice had

  11. Calcium: the molecular basis of calcium action in biology and medicine

    National Research Council Canada - National Science Library

    Pochet, Roland; Donato, Rosario

    2000-01-01

    ... of Calcium Calcium Signalling in Excitable Cells Ca2+ Release in Muscle Cells by N. Macrez and J. Mironneau Calcium Signalling in Neurons Exemplified by Rat Sympathetic Ganglion Cells by S.J. M...

  12. Endocytic mechanisms and osteoinductive profile of hydroxyapatite nanoparticles in human umbilical cord Wharton’s jelly-derived mesenchymal stem cells

    Science.gov (United States)

    Zhang, Juan; Wang, Chen

    2018-01-01

    Background As a potentially bioactive material, the widespread application of nanosized hydroxyapatite (nano-HAP) in the field of bone regeneration has increased the risk of human exposure. However, our understanding of the interaction between nano-HAP and stem cells implicated in bone repair remains incomplete. Methods Here, we characterized the adhesion and cellular internalization of HAP nanoparticles (HANPs) with different sizes (20 nm np20 and 80 nm np80) and highlighted the involved pathway in their uptake using human umbilical cord Wharton’s jelly-derived mesenchymal stem cells (hWJ-MSCs). In addition, the effects of HANPs on cell viability, apoptosis response, osteogenic differentiation, and underlying related mechanisms were explored. Results It was shown that both types of HANPs readily adhered to the cellular membrane and were transported into the cells compared to micro-sized HAP particles (m-HAP; 12 μm). Interestingly, the endocytic routes of np20 and np80 differed, although they exhibited similar kinetics of adhesion and uptake. Our study revealed involvement of clathrin- and caveolin-mediated endocytosis as well as macropinocytosis in the np20 uptake. However, for np80, clathrin-mediated endocytosis and some as-yet-unidentified important uptake routes play central roles in their internalization. HANPs displayed a higher preference to accumulate in the cytoplasm compared to m-HAP, and HANPs were not detected in the nucleolus. Exposure to np20 for 24 h caused a decrease in cell viability, while cells completely recovered with an exposure time of 72 h. Furthermore, HANPs did not influence apoptosis and necrosis of hWJ-MSCs. Strikingly, HANPs enhanced mRNA levels of osteoblast-related genes and stimulated calcium mineral deposition, and this directly correlated with the activation in c-Jun N-terminal kinases and p38 pathways. Conclusion Our data provide additional insight about the interactions of HANPs with MSCs and suggest their application

  13. Stochastic Simulation of Cardiac Ventricular Myocyte Calcium Dynamics and Waves

    OpenAIRE

    Tuan, Hoang-Trong Minh; Williams, George S. B.; Chikando, Aristide C.; Sobie, Eric A.; Lederer, W. Jonathan; Jafri, M. Saleet

    2011-01-01

    A three dimensional model of calcium dynamics in the rat ventricular myocyte was developed to study the mechanism of calcium homeostasis and pathological calcium dynamics during calcium overload. The model contains 20,000 calcium release units (CRUs) each containing 49 ryanodine receptors. The model simulates calcium sparks with a realistic spontaneous calcium spark rate. It suggests that in addition to the calcium spark-based leak, there is an invisible calcium leak caused by the stochastic ...

  14. Lead in calcium supplements (abstract)

    International Nuclear Information System (INIS)

    Rehman, S.; Khalid, N.

    2011-01-01

    Lead present in calcium supplements is of grave concern as some lead levels have been measured up to the extent of regulatory limit set by the United States. Calcium supplements inevitably get contaminated with lead as both are naturally occurring elements. Therefore, it is imperative to indicate its level in these supplements in order to create awareness among consumers. In this study, a sophisticated analytical technique, atomic absorption spectrometry was used to analyze Pb contents in 27 commonly consumed Ca supplements manufactured by different national and multinational companies. The daily intake of lead through these supplements was calculated. Only 10% of the calcium supplements analyzed met the criteria of acceptable Pb levels (1.5 mu g/daily dose) in supplements/consumer products set by the United States. It was also found that Pb intake was highest in chelated calcium supplements 28.5 mu g/daily dose, whereas lowest 0.47 mu g/daily dose through calcium supplements with vitamin D formulation. In order to validate our results from the study conducted, IAEA-certified reference material (animal bone, H-5) was analyzed for its Pb levels. The levels of Pb determined were quite in good agreement with the certified values. (author)

  15. Osteoconduction of impacted porous titanium particles with a calcium-phosphate coating is comparable to osteoconduction of impacted allograft bone particles: in vivo study in a nonloaded goat model.

    Science.gov (United States)

    Walschot, Lucas H B; Aquarius, René; Schreurs, Barend W; Verdonschot, Nico; Buma, Pieter

    2012-08-01

    Impaction grafting restores bone defects in hip arthroplasty. Defects are reconstructed with bone particles (BoP) as substitute materials with adequate mechanical and biological properties are not yet available. Ceramic particles (CeP) have mechanical drawbacks as opposed to porous titanium particles (TiP). In this in vivo study, bone ingrowth and bone volume in coated and noncoated TiP were compared to porous biphasic calcium-phospate CeP and allograft BoP. Coatings consisted of silicated calcium-phosphate and carbonated apatite. Materials were implanted in goats and impacted in cylindrical defects (diameter 8 mm) in the cancellous bone of the femur. On the basis of fluorochrome labeling and histology, bone ingrowth distance was measured at 4, 8, and 12 weeks. Cross-sectional bone area was measured at 12 weeks. TiP created a coherent matrix of entangled particles. CeP pulverized and were noncoherent. Bone ingrowth in TiP improved significantly by the coatings to levels comparable to BoP and CeP. Cross-sectional bone area was smaller in CeP and TiP compared to BoP. The osteoconductive properties of impacted TiP with a calcium-phosphate coating are comparable to impacted allograft bone and impacted biphasic ceramics. A more realistic loaded in vivo study should prove that coated TiP is an attractive alternative to allograft bone. Copyright © 2012 Wiley Periodicals, Inc.

  16. Influences of the steam sterilization on the properties of calcium phosphate porous bioceramics.

    Science.gov (United States)

    Li, Xiangfeng; Guo, Bo; Xiao, Yumei; Yuan, Tun; Fan, Yujiang; Zhang, Xingdong

    2016-01-01

    The influences of steam sterilization on the physicochemical properties of calcium phosphate (Ca-P) porous bioceramics, including β-tricalcium phosphate (β-TCP), biphasic calcium phosphate (BCP) and hydroxyapatite (HA) are investigated. After being steam sterilized in an autoclave (121 °C for 40 min), the porous bioceramics are dried and characterized. The steam sterilization has no obvious effects on the phase composition, thermal stability, pH value and dissolubility of β-TCP porous bioceramic, but changes its morphology and mechanical strength. Meanwhile, the steam sterilization leads to the significant changes of the morphology, phase composition, pH value and dissolubility of BCP porous bioceramic. The increase of dissolubility and mechanical strength, the decrease of pH value of the immersed solution and partial oriented growth of crystals are also observed in HA porous bioceramic after steam sterilization. These results indicate that the steam sterilization can result in different influences on the physicochemical properties of β-TCP, BCP and HA porous bioceramics, thus the application of the steam sterilization on the three kinds of Ca-P porous bioceramics should be considered carefully based on the above changed properties.

  17. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Hilbert

    1962-12-15

    By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca{sub 9}Sr(PO{sub 4}){sub 6}(OH){sub 2} - CaSr{sub 9}(PO{sub 4}){sub 6}(OH){sub 2}. The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice.

  18. Biphasic electrical targeting plays a significant role in schwann cell activation.

    Science.gov (United States)

    Kim, In Sook; Song, Yun Mi; Cho, Tae Hyung; Pan, Hui; Lee, Tae Hyung; Kim, Sung June; Hwang, Soon Jung

    2011-05-01

    Electrical stimulation (ES) is a promising technique for axonal regeneration of peripheral nerve injuries. However, long-term, continuous ES in the form of biphasic electric current (BEC) to stimulate axonal regeneration has rarely been attempted and the effects of BEC on Schwann cells are unknown. We hypothesized that long-term, continuous ES would trigger the activation of Schwann cells, and we therefore investigated the effect of BEC on the functional differentiation of primary human mesenchymal stromal cells (hMSCs) into Schwann cells, as well as the activity of primary Schwann cells. Differentiation of hMSCs into Schwann cells was determined by coculture with rat pheochromocytoma cells (PC12 cell line). We also investigated the in vivo effects of long-term ES (4 weeks) on axonal outgrowth of a severed sciatic nerve with a 7-mm gap after retraction of the nerve ends in rats by implanting an electronic device to serve as a neural conduit. PC12 cells cocultured with hMSCs electrically stimulated during culture in Schwann cell differentiation medium (Group I) had longer neurites and a greater percentage of PC12 cells were neurite-sprouting than when cocultured with hMSCs cultured in growth medium (control group) or unstimulated hMSCs in the same culture conditions as used for Group I (Group II). Group I cells showed significant upregulation of Schwann cell-related neurotrophic factors such as nerve growth factor and glial-derived neurotrophic factor compared to Group II cells at both the mRNA and protein levels. Primary Schwann cells responded to continuous BEC with increased proliferation and the induction of nerve growth factor and glial-derived neurotrophic factor, similar to Group I cells, and in addition, induction of brain-derived neurotrophic factor was observed. Immunohistochemical investigation of sciatic nerve regenerates revealed that BEC increased axonal outgrowth significantly. These results demonstrate that BEC enhanced the functional activity of

  19. Biphasic character of ribosomal translocation and non-Michaelis-Menten kinetics of translation

    Science.gov (United States)

    Xie, Ping

    2014-12-01

    We study theoretically the kinetics of mRNA translocation in the wild-type (WT) Escherichia coli ribosome, which is composed of a small 30 S and large 50 S subunit, and the ribosomes with mutations to some intersubunit bridges such as B1a, B4, B7a, and B8. The theoretical results reproduce well the available in vitro experimental data on the biphasic kinetics of the forward mRNA translocation catalyzed by elongation factor G (EF-G) hydrolyzing GTP, which can be best fit by the sum of two exponentials, and the monophasic kinetics of the spontaneous reverse mRNA translocation in the absence of the elongation factor, which can be best fit by a single-exponential function, in both the WT and mutant ribosomes. We show that both the mutation-induced increase in the maximal rate of the slow phase for the forward mRNA translocation and that in the rate of the spontaneous reverse mRNA translocation result from a reduction in the intrinsic energy barrier to resist the rotational movements between the two subunits, giving the same degree of increase in the two rates. The mutation-induced increase in the maximal rate of the fast phase for the forward mRNA translocation results mainly from the increase in the rate of the ribosomal unlocking, a conformational change in the ribosome that widens the mRNA channel for the mRNA translocation to take place, which could be partly due to the effect of the mutation on the intrasubunit 30S head rotation. Moreover, we study the translation rate of the WT and mutant ribosomes. It is shown that the translation rate versus the concentration of EF-G-GTP does not follow the Michaelis-Menten (MM) kinetics, which is in sharp contrast to the general property of other enzymes that the rate of the enzymatic reaction versus the concentration of a substrate follows the MM kinetics. The physical origin of this non-MM kinetics for the ribosome is revealed.

  20. Electrophysical properties of calcium vanadates

    International Nuclear Information System (INIS)

    Krasnenko, T.I.; Fotiev, A.A.

    1983-01-01

    Electrophysical properties of calcium vanadates are studied for the case of alteration of external parameters of the medium (PO 2 , T). It is lshown that structural transformations bring about changes in the nature of electrophysical properties of Ca 2 V 2 O 7 , Ca 3 (VO 4 ) 2 , this being the reason for charge redistribution in anion groupings. It is obvious, that the general conductivity of calcium methavanadate is mainly caused by ion transport. Ca(VO 3 ) 2 possesses amphoteric character of semiconducting properties: the type of conductivity changes from ''p'' to ''n'' with temperature increase. Polytherms of conductivity and sums of ion numbers of Ca 2 V 2 O 7 transition are given. It is established that calcium pyrovanadate has a mixed electron-ion conductivity

  1. Preparation of calcium phosphate paste

    International Nuclear Information System (INIS)

    Mohd Reusmaazran Yusof; Norzita Yaacob; Idris Besar; Che Seman Mahmood; Rusnah Mustafa

    2010-01-01

    Calcium phosphate paste were prepared by mixing between calcium sodium potassium phosphate, Ca 2 NaK (PO 4 ) 2 (CSPP) and monocalcium phosphate monohydrate, Ca(H 2 PO 4 ) 2 .H 2 O (MCPM). CSPP were obtained by reaction between calcium hydrogen phosphate (CaHPO 4 ), potassium carbonate (K 2 CO 3 ) and sodium carbonate (Na 2 CO 3 ) in solid state sintering process followed by quenching in air at 1000 degree Celsius. The paste was aging in simulated body fluid (SBF) for 0.5, 1, 3, 6, 12, 24, 48 hrs, 3, 7 and 14 days. The morphological investigation indicated the formation of apatite crystal were first growth after 24 hours. The obvious growth of apatite crystal was shown at 3 days. The obvious growth of apatite crystal was shown in 7 and 14 days indicated the prediction of paste would have rapid reaction with bone after implantation. (author)

  2. Uptake of radiactive calcium by groundnut (Arachis hypogaea L. ) and efficiency of utilisation of applied calcium

    Energy Technology Data Exchange (ETDEWEB)

    Loganathan, S; Krishnamoorthy, K K [Tamil Nadu Agricultural Univ., Coimbatore (India). Dept. of Soil Science and Agricultural Chemistry

    1977-04-01

    A pot experiment was conducted with groundnut applying labelled calcium as its sulphate and carbonate at two levels namely 75 and 150 kg Ca per ha with varying levels of P, K and Mg. Plant samples were taken at different stages of crop growth and analysed for the content of radioactive calcium. Calcium sulphate treatment has resulted in larger uptake of calcium compared to calcium carbonate. An application of 150 kg Ca per ha has caused significantly higher uptake by groundnut plant than 75 kg Ca per ha. The percentage of utilisation of added calcium ranged from 2.2 to 5.4 Recovery of calcium by plants was more in calcium sulphate treatment rather than in calcium carbonate. The plants showed a preference for absorbing applied calcium rather than native calcium.

  3. Uptake of radiactive calcium by groundnut (Arachis hypogaea L.) and efficiency of utilisation of applied calcium

    International Nuclear Information System (INIS)

    Loganathan, S.; Krishnamoorthy, K.K.

    1977-01-01

    A pot experiment was conducted with groundnut applying labelled calcium as its sulphate and carbonate at two levels namely 75 and 150 kg Ca per ha with varying levels of P, K and Mg. Plant samples were taken at different stages of crop growth and analysed for the content of radioactive calcium. Calcium sulphate treatment has resulted in larger uptake of calcium compared to calcium carbonate. An application of 150 kg Ca per ha has caused significantly higher uptake by groundnut plant than 75 kg Ca per ha. The percentage of utilisation of added calcium ranged from 2.2 to 5.4 Recovery of calcium by plants was more in calcium sulphate treatment rather than in calcium carbonate. The plants showed a preference for absorbing applied calcium rather than native calcium

  4. The effect of habitat geology on calcium intake and calcium status of wild rodents.

    Science.gov (United States)

    Shore, R F; Balment, R J; Yalden, D W

    1991-12-01

    Calcium is essential for normal physiological function, reproduction and growth in mammals but its distribution in the natural environment is heterogeneous. Spatial variation in calcium soil content is especially marked in the Peak District, United Kingdom, where both calcium-rich limestone and calcium-poor gritstone rock types occur. Wood mice Apodemus sylvaticus (L) and bank voles Clethrionomys glareolus (Schreber 1780) from limestone areas had significantly higher calcium concentrations in stomach contents and in faeces compared with their counterparts from gritstone areas. Calcium status was assessed from serum calcium concentration, femur weight, ash content of the body, calcium concentration in the femur and body ash. There was no significant difference in serum calcium concentration, femur calcium concentration and body ash calcium concentration between animals from the limestone and the gritstone. However, on the limestone, bank voles, but not wood mice, had significantly heavier femora and a greater proportion of ash in the body compared with their gritstone counterparts.

  5. Calcium and Bone Metabolism Indices.

    Science.gov (United States)

    Song, Lu

    2017-01-01

    Calcium and inorganic phosphate are of critical importance for many body functions, thus the regulations of their plasma concentrations are tightly controlled by the concerted actions of reabsorption/excretion in the kidney, absorption in the intestines, and exchange from bone, the major reservoir for calcium and phosphate in the body. Parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D (1,25(OH) 2 D) control calcium homeostasis, whereas PTH, 1,25(OH) 2 D, and bone-derived fibroblast growth factor 23 (FGF 23) control phosphate homeostasis. Hypoparathyroidism can cause hypocalcemia and hyperphosphatemia, whereas deficient vitamin D actions can cause osteomalacia in adults and rickets in children. Hyperparathyroidism, alternatively, can cause hypercalcemia and hypophosphatemia. Laboratory tests of calcium, phosphate, PTH, and 25-hydroxyvitamin D are very useful in the diagnosis of abnormalities associated with calcium and/or phosphate metabolisms. Bone is constantly remodeled throughout life in response to mechanical stress and a need for calcium in extracellular fluids. Metabolic bone diseases such as osteoporosis, osteomalacia in adults or rickets in children, and renal osteodystrophy develop when bone resorption exceeds bone formation. Bone turnover markers (BTM) such as serum N-terminal propeptide of type I procollagen (P1NP) and C-terminal collagen cross-link (CTX) may be useful in predicting future fracture risk or monitoring the response to anti-resorptive therapy. There is a need to standardize sample collection protocols because certain BTMs exhibit large circadian variations and tend to be influenced by food intakes. In the United States, a project to standardize BTM sample collection protocols and to establish the reference intervals for serum P1NP and serum CTX is ongoing. We anticipate the outcome of this project to shine lights on the standardization of BTM assays, sample collection protocols, reference intervals in relation to age, sex, and ethnic

  6. Magnetically responsive calcium carbonate microcrystals.

    Science.gov (United States)

    Fakhrullin, Rawil F; Bikmullin, Aidar G; Nurgaliev, Danis K

    2009-09-01

    Here we report the fabrication of magnetically responsive calcium carbonate microcrystals produced by coprecipitation of calcium carbonate in the presence of citrate-stabilized iron oxide nanoparticles. We demonstrate that the calcite microcrystals obtained possess superparamagnetic properties due to incorporated magnetite nanoparticles and can be manipulated by an external magnetic field. The microcrystals doped with magnetic nanoparticles were utilized as templates for the fabrication of hollow polyelectrolyte microcapsules, which retain the magnetic properties of the sacrificial cores and might be spatially manipulated using a permanent magnet, thus providing the magnetic-field-facilitated delivery and separation of materials templated on magnetically responsive calcite microcrystals.

  7. Biphasic effect of arsenite on cell proliferation and apoptosis is associated with the activation of JNK and ERK1/2 in human embryo lung fibroblast cells

    International Nuclear Information System (INIS)

    He Xiaoqing; Chen Rui; Yang Ping; Li Aiping; Zhou Jianwei; Liu Qizhan

    2007-01-01

    Biphasic dose-response relationship induced by environmental agents is often characterized with the effect of low-dose stimulation and high-dose inhibition. Some studies showed that arsenite may induce cell proliferation and apoptosis via biphasic dose-response relationship in human cells; however, mechanisms underlying this phenomenon are not well understood. In the present study, we aimed at investigating the relationship between biphasic effect of arsenite on cell proliferation and apoptosis and activation of JNK and ERK1/2 in human embryo lung fibroblast (HELF) cells. Our results demonstrated that cell proliferation may be stimulated at lower concentrations (0.1 and 0.5 μM) arsenite but inhibited at higher concentrations (5 and 10 μM). When cell apoptosis was used as the endpoint, the concentration-response curves were changed to U-shapes. During stimulation phospho-JNK levels were significantly increased at 3, 6, and 12 h after 0.1 or 0.5 μM arsenite exposure. Phospho-ERK1/2 levels were increased with different concentrations (0.1-10 μM) of arsenite at 6, 12, and 24 h. Blocking of JNK pathway with 20 μM SP600125 or ERK1/2 by 100 μM PD98059 significantly inhibited biphasic effect of arsenite in cells. Data in the present study suggest that activation of JNK and ERK1/2 may be involved in biphasic effect of arsenite when measuring cell proliferation and apoptosis in HELF cells. JNK activation seems to play a more critical role than ERK1/2 activation in the biphasic process

  8. Trophic Ecology of Benthic Marine Invertebrates with Bi-Phasic Life Cycles: What Are We Still Missing?

    Science.gov (United States)

    Calado, Ricardo; Leal, Miguel Costa

    2015-01-01

    The study of trophic ecology of benthic marine invertebrates with bi-phasic life cycles is critical to understand the mechanisms shaping population dynamics. Moreover, global climate change is impacting the marine environment at an unprecedented level, which promotes trophic mismatches that affect the phenology of these species and, ultimately, act as drivers of ecological and evolutionary change. Assessing the trophic ecology of marine invertebrates is critical to understanding maternal investment, larval survival to metamorphosis, post-metamorphic performance, resource partitioning and trophic cascades. Tools already available to assess the trophic ecology of marine invertebrates, including visual observation, gut content analysis, food concentration, trophic markers, stable isotopes and molecular genetics, are reviewed and their main advantages and disadvantages for qualitative and quantitative approaches are discussed. The challenges to perform the partitioning of ingestion, digestion and assimilation are discussed together with different approaches to address each of these processes for short- and long-term fingerprinting. Future directions for research on the trophic ecology of benthic marine invertebrates with bi-phasic life cycles are discussed with emphasis on five guidelines that will allow for systematic study and comparative meta-analysis to address important unresolved questions. © 2015 Elsevier Ltd. All rights reserved.

  9. Leaf-Cutter Ant Fungus Gardens Are Biphasic Mixed Microbial Bioreactors That Convert Plant Biomass to Polyols with Biotechnological Applications

    Science.gov (United States)

    Somera, Alexandre F.; Lima, Adriel M.; dos Santos-Neto, Álvaro J.; Lanças, Fernando M.

    2015-01-01

    Leaf-cutter ants use plant matter to culture the obligate mutualistic basidiomycete Leucoagaricus gongylophorus. This fungus mediates ant nutrition on plant resources. Furthermore, other microbes living in the fungus garden might also contribute to plant digestion. The fungus garden comprises a young sector with recently incorporated leaf fragments and an old sector with partially digested plant matter. Here, we show that the young and old sectors of the grass-cutter Atta bisphaerica fungus garden operate as a biphasic solid-state mixed fermenting system. An initial plant digestion phase occurred in the young sector in the fungus garden periphery, with prevailing hemicellulose and starch degradation into arabinose, mannose, xylose, and glucose. These products support fast microbial growth but were mostly converted into four polyols. Three polyols, mannitol, arabitol, and inositol, were secreted by L. gongylophorus, and a fourth polyol, sorbitol, was likely secreted by another, unidentified, microbe. A second plant digestion phase occurred in the old sector, located in the fungus garden core, comprising stocks of microbial biomass growing slowly on monosaccharides and polyols. This biphasic operation was efficient in mediating symbiotic nutrition on plant matter: the microbes, accounting for 4% of the fungus garden biomass, converted plant matter biomass into monosaccharides and polyols, which were completely consumed by the resident ants and microbes. However, when consumption was inhibited through laboratory manipulation, most of the plant polysaccharides were degraded, products rapidly accumulated, and yields could be preferentially switched between polyols and monosaccharides. This feature might be useful in biotechnology. PMID:25911490

  10. Direct transformation of xylan-type hemicelluloses to furfural via SnCl₄ catalysts in aqueous and biphasic systems.

    Science.gov (United States)

    Wang, Wenju; Ren, Junli; Li, Huiling; Deng, Aojie; Sun, Runcang

    2015-05-01

    Direct catalytic transformation of xylan-type hemicelluloses to furfural in the aqueous system and the biphasic system were comparatively investigated under mild conditions. Screening of several promising chlorides for conversion of beech xylan in the aqueous system revealed the Lewis acid SnCl4 was the most effective catalyst. Comparing to the single aqueous system, the bio-based 2-methyltetrahydrofuran (2-MTHF)/H2O biphasic system was more conducive to the synthesis of furfural, in which the highest furfural yield of 78.1% was achieved by using SnCl4 as catalysts under the optimized reaction conditions (150°C, 120 min). Additionally, the influences of xylan-type hemicelluloses with different chemical and structural features from beech, corncob and bagasse on the furfural production were studied. It was found that furfural yield to some extent was determined by the xylose content in hemicelluloses and also had relationships with the molecular weight of hemicelluloses and the degree of crystallization. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Lignocellulose fractionation into furfural and glucose by AlCl3-catalyzed DES/MIBK biphasic pretreatment.

    Science.gov (United States)

    Wang, Zhi-Kun; Shen, Xiao-Jun; Chen, Jun-Jie; Jiang, Ying-Qiu; Hu, Zhi-Yan; Wang, Xing; Liu, Li

    2018-06-01

    Herein, an efficient DES/MIBK biphasic pretreatment system for preparation of furfural and fermentable glucose from lignocellulose was developed with AlCl 3 as catalysis. The low-cost and renewable DES (Choline chloride-Oxalic acid) served not only as a Brønsted acid catalyst, but also as a pretreatment solvent in present work, and MIBK as an extracting reagent which can increase the yield of furfural in DES phase. The effects of this biphasic pretreatment on the furfural yield and saccharification of the lignocellulose before and after pretreatment were explored using HPLC, HAPEC, FT-IR, XRD and SEM. Under the best pretreatment condition (at 140 °C for 90 min), furfural could be obtained in 70.3% yield and 80.8% of the pretreated lignocellulose was saccharified, which was 8.4 times higher than that of the raw lignocellulose without pretreatment. In a word, this pretreatment system can be considered as a potential technique for efficient valorization of lignocellulose for production of furfural and fermentable glucose. Copyright © 2018. Published by Elsevier B.V.

  12. Effect of Ganoderma lucidum on pollen-induced biphasic nasal blockage in a guinea pig model of allergic rhinitis.

    Science.gov (United States)

    Mizutani, Nobuaki; Nabe, Takeshi; Shimazu, Masaji; Yoshino, Shin; Kohno, Shigekatsu

    2012-03-01

    Ganoderma lucidum (GL), an oriental medical mushroom, has been used in Asia for the prevention and treatment of a variety of diseases. However, the effect of GL on allergic rhinitis has not been well defined. The current study describes the inhibitory effect of GL on the biphasic nasal blockage and nasal hyperresponsiveness induced by repeated antigen challenge in a guinea pig model of allergic rhinitis. Intranasally sensitized guinea pigs were repeatedly challenged by inhalation of Japanese cedar pollen once every week. Ganoderma lucidum was orally administered once daily for 8 weeks from the time before the first challenge. The treatment with GL dose-dependently inhibited the early and late phase nasal blockage at the fifth to ninth antigen challenges. Furthermore, nasal hyperresponsiveness to intranasally applied leukotriene D₄ on 2 days after the eighth antigen challenge was also inhibited by the treatment with GL. However, Cry j 1-specific IgE antibody production was not affected by the treatment. In conclusion, we demonstrated that the pollen-induced biphasic nasal blockage and nasal hyperresponsiveness were suppressed by the daily treatment with GL in the guinea pig model of allergic rhinitis. These results suggest that GL may be a useful therapeutic drug for treating patients with allergic rhinitis. Copyright © 2011 John Wiley & Sons, Ltd.

  13. Low temperature N,N-dimethylformamide-assisted synthesis and characterization of anatase-rutile biphasic nanostructured titania

    Energy Technology Data Exchange (ETDEWEB)

    Estruga, M; Domenech, X; Ayllon, J A [Departament de Quimica, Universitat Autonoma de Barcelona, Campus UAB, E-08193 Bellaterra (Spain); Domingo, C [Institut de Ciencia dels Materials de Barcelona (CSIC), Campus UAB, E-08193 Bellaterra (Spain)], E-mail: joseantonio.ayllon@uab.es, E-mail: mestruga@qf.uab.cat

    2009-03-25

    Anatase and rutile biphasic nanostructured titania (TiO{sub 2}) has been synthesized via hydrolysis of titanium tetraisopropoxide in an aqueous solution of hydrobromic acid (HBr) and N,N-dimethylformamide (DMF) at 80 deg. C for 16 h. The presence of DMF, which was partially hydrolyzed during the process, determined the formation of a biphasic material. Powder x-ray diffraction showed the presence of both anatase and rutile titania phases in a ratio of approx. 1:1. Transmission electron microscope analysis showed that rutile was present as radial flower-like nanorods, which were surrounded by anatase spherical nanoparticles of 5 nm diameter. Low temperature nitrogen adsorption-desorption analysis showed the characteristic hysteresis loop of a mesoporous material. Specific surface area reached a value of 120 m{sup 2} g{sup -1} and the average pore diameter was 50 A. X-ray photoelectron spectroscopic analysis revealed that interstitial nitrogen was incorporated (0.35 at.%) during the annealing process. According to ultraviolet (UV)-visible diffuse reflectance spectroscope characterization, the N-doping caused a bandgap reduction from 3.0 to 2.9 eV. Photocatalytic activity of the material was tested for the degradation of methylene blue, methyl orange and 4-nitrophenol under near-UV and visible light radiation.

  14. Diagnostic accuracy of segmental enhancement inversion for diagnosis of renal oncocytoma at biphasic contrast enhanced CT: systematic review

    International Nuclear Information System (INIS)

    Schieda, Nicola; McInnes, Matthew D.F.; Cao, Lilly

    2014-01-01

    To use systematic review to evaluate the diagnostic accuracy of segmental enhancement inversion (SEI) at contrast-enhanced biphasic multi-detector computed tomography (MDCT) for the diagnosis of renal oncocytoma. Several electronic databases were searched through October 2013. Two reviewers independently selected studies that met the inclusion criteria and extracted data. Study quality was assessed with the QUADAS-2 tool. The primary 2 x 2 data were investigated with forest plot and ROC plot of sensitivity and specificity. Four studies met the inclusion criteria (307 patients). Considerable heterogeneity between studies precluded meta-analysis. Two studies from the same group of investigators demonstrated reasonable diagnostic accuracy (sensitivity 59-80 % and specificity 87-99 %), while two others did not (sensitivity 0-6 %, specificity 93-100 %). Possible reasons for this include timing of biphasic MDCT and methods of interpretation but not size of lesion. SEI is a specific imaging finding of renal oncocytoma with highly variable sensitivity. This substantial heterogeneity across studies and between institutions suggests that further validation of this imaging finding is necessary prior to application in clinical practice. (orig.)

  15. Diagnostic accuracy of segmental enhancement inversion for diagnosis of renal oncocytoma at biphasic contrast enhanced CT: systematic review

    Energy Technology Data Exchange (ETDEWEB)

    Schieda, Nicola; McInnes, Matthew D.F.; Cao, Lilly [Ottawa Hospital Research Institute, Department of Medical Imaging, Ottawa, ON (Canada)

    2014-06-15

    To use systematic review to evaluate the diagnostic accuracy of segmental enhancement inversion (SEI) at contrast-enhanced biphasic multi-detector computed tomography (MDCT) for the diagnosis of renal oncocytoma. Several electronic databases were searched through October 2013. Two reviewers independently selected studies that met the inclusion criteria and extracted data. Study quality was assessed with the QUADAS-2 tool. The primary 2 x 2 data were investigated with forest plot and ROC plot of sensitivity and specificity. Four studies met the inclusion criteria (307 patients). Considerable heterogeneity between studies precluded meta-analysis. Two studies from the same group of investigators demonstrated reasonable diagnostic accuracy (sensitivity 59-80 % and specificity 87-99 %), while two others did not (sensitivity 0-6 %, specificity 93-100 %). Possible reasons for this include timing of biphasic MDCT and methods of interpretation but not size of lesion. SEI is a specific imaging finding of renal oncocytoma with highly variable sensitivity. This substantial heterogeneity across studies and between institutions suggests that further validation of this imaging finding is necessary prior to application in clinical practice. (orig.)

  16. Potassium-induced contraction in the lamb proximal urethra: Involvement of norepinephrine and different calcium entry pathways

    International Nuclear Information System (INIS)

    Garcia-Pascual, A.; Costa, G.; Isla, M.; Jimenez, E.; Garcia-Sacristan, A.

    1991-01-01

    The purpose of this work was to investigate the mechanisms involved in the peculiar biphasic response of the lamb urethral smooth muscle to high K+ solutions. The relative amplitude of the phasic and tonic components of the contraction and its reproducibility were dependent on the concentration of K+ used. Only concentrations higher than 80 mM (i.e., 120 mM) showed a tonic component greater in amplitude than the phasic one and manifested a tachyphylactic effect. Phentolamine (10(-6) M), prazosin (10(-6) M) and chemical denervation with 6-hydroxydopamine significantly inhibited the tonic component of the K+ (120 mM)-induced contraction, modifying its morphology. Reproducible contractions to K+ (120 mM) could be obtained in the presence of prazosin (10(-6) M) or cocaine (10(-6) M). The preparations were also shown to accumulate [3H]noradrenaline and release it upon depolarization with K+ (60 and 120 mM). Calcium removal inhibited the K+ (120 mM)-induced contraction. After addition of calcium (0.5-5 mM) the contractile activity was restored. Nifedipine (10(-6) M) and verapamil (10(-6) M) but not sodium nitroprusside (10(-6) M) significantly blocked the contractile response for calcium as well as the phasic component of the K+ contraction in calcium-containing medium. In preparations treated with prazosin (10(-6) M) the tonic component of the K+ (120 mM) contraction was more sensitive to nifedipine and removal of extracellular calcium than the phasic one

  17. Application of a Three-Dimensional Poroelastic BEM to Modeling the Biphasic Mechanics of Cell-Matrix Interactions in Articular Cartilage (REVISION).

    Science.gov (United States)

    Haider, Mansoor A; Guilak, Farshid

    2007-06-15

    Articular cartilage exhibits viscoelasticity in response to mechanical loading that is well described using biphasic or poroelastic continuum models. To date, boundary element methods (BEMs) have not been employed in modeling biphasic tissue mechanics. A three dimensional direct poroelastic BEM, formulated in the Laplace transform domain, is applied to modeling stress relaxation in cartilage. Macroscopic stress relaxation of a poroelastic cylinder in uni-axial confined compression is simulated and validated against a theoretical solution. Microscopic cell deformation due to poroelastic stress relaxation is also modeled. An extended Laplace inversion method is employed to accurately represent mechanical responses in the time domain.

  18. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes.

    Science.gov (United States)

    Samigullin, Dmitry; Fatikhov, Nijaz; Khaziev, Eduard; Skorinkin, Andrey; Nikolsky, Eugeny; Bukharaeva, Ellya

    2014-01-01

    At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers-which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal-has hitherto been technically impossible. With the aim of quantifying both Ca(2+) currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 pA and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 μM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

  19. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes

    Directory of Open Access Journals (Sweden)

    Dmitry eSamigullin

    2015-01-01

    Full Text Available At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers—which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal—has hitherto been technically impossible. With the aim of quantifying both Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 рА and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 µM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

  20. Calcium electroporation in three cell lines; a comparison of bleomycin and calcium, calcium compounds, and pulsing conditions

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gissel, Hanne; Hojman, Pernille

    2013-01-01

    offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium...

  1. Calcium fertilization increases the concentration of calcium in sapwood and calcium oxalate in foliage of red spruce

    Science.gov (United States)

    Kevin T. Smith; Walter C. Shortle; Jon H. Connolly; Rakesh Minocha; Jody Jellison

    2009-01-01

    Calcium cycling plays a key role in the health and productivity of red spruce forests in the northeastern US. A portion of the flowpath of calcium within forests includes translocation as Ca2+ in sapwood and accumulation as crystals of calcium oxalate in foliage. Concentrations of Ca in these tree tissues have been used as markers of...

  2. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

    ... Bone Health Featured Resource Find an Endocrinologist Search Vitamin D, Calcium, and Bone Health Download PDFs English ... also helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin ...

  3. Complex formation ions calcium with macromolecules pectin

    International Nuclear Information System (INIS)

    Khalikova, M.D.; Avloev, Kh.Kh.; Muhiddinov, Z.K.

    2005-01-01

    In clause the mechanism of sorption of ions of calcium by macromolecules of pectin is opened. Is shown, that the linkage of ions of calcium descends on acid bunches of pectin, and process carries cooperative character

  4. Atomic layer deposition of calcium oxide and calcium hafnium oxide films using calcium cyclopentadienyl precursor

    International Nuclear Information System (INIS)

    Kukli, Kaupo; Ritala, Mikko; Sajavaara, Timo; Haenninen, Timo; Leskelae, Markku

    2006-01-01

    Calcium oxide and calcium hafnium oxide thin films were grown by atomic layer deposition on borosilicate glass and silicon substrates in the temperature range of 205-300 o C. The calcium oxide films were grown from novel calcium cyclopentadienyl precursor and water. Calcium oxide films possessed refractive index 1.75-1.80. Calcium oxide films grown without Al 2 O 3 capping layer occurred hygroscopic and converted to Ca(OH) 2 after exposure to air. As-deposited CaO films were (200)-oriented. CaO covered with Al 2 O 3 capping layers contained relatively low amounts of hydrogen and re-oriented into (111) direction upon annealing at 900 o C. In order to examine the application of CaO in high-permittivity dielectric layers, mixtures of Ca and Hf oxides were grown by alternate CaO and HfO 2 growth cycles at 230 and 300 o C. HfCl 4 was used as a hafnium precursor. When grown at 230 o C, the films were amorphous with equal amounts of Ca and Hf constituents (15 at.%). These films crystallized upon annealing at 750 o C, showing X-ray diffraction peaks characteristic of hafnium-rich phases such as Ca 2 Hf 7 O 16 or Ca 6 Hf 19 O 44 . At 300 o C, the relative Ca content remained below 8 at.%. The crystallized phase well matched with rhombohedral Ca 2 Hf 7 O 16 . The dielectric films grown on Si(100) substrates possessed effective permittivity values in the range of 12.8-14.2

  5. Kinetics of calcium sulfoaluminate formation from tricalcium aluminate, calcium sulfate and calcium oxide

    International Nuclear Information System (INIS)

    Li, Xuerun; Zhang, Yu; Shen, Xiaodong; Wang, Qianqian; Pan, Zhigang

    2014-01-01

    The formation kinetics of tricalcium aluminate (C 3 A) and calcium sulfate yielding calcium sulfoaluminate (C 4 A 3 $) and the decomposition kinetics of calcium sulfoaluminate were investigated by sintering a mixture of synthetic C 3 A and gypsum. The quantitative analysis of the phase composition was performed by X-ray powder diffraction analysis using the Rietveld method. The results showed that the formation reaction 3Ca 3 Al 2 O 6 + CaSO 4 → Ca 4 Al 6 O 12 (SO 4 ) + 6CaO was the primary reaction 4 Al 6 O 12 (SO 4 ) + 10CaO → 6Ca 3 Al 2 O 6 + 2SO 2 ↑ + O 2 ↑ primarily occurred beyond 1350 °C with an activation energy of 792 ± 64 kJ/mol. The optimal formation region for C 4 A 3 $ was from 1150 °C to 1350 °C and from 6 h to 1 h, which could provide useful information on the formation of C 4 A 3 $ containing clinkers. The Jander diffusion model was feasible for the formation and decomposition of calcium sulfoaluminate. Ca 2+ and SO 4 2− were the diffusive species in both the formation and decomposition reactions. -- Highlights: •Formation and decomposition of calcium sulphoaluminate were studied. •Decomposition of calcium sulphoaluminate combined CaO and yielded C 3 A. •Activation energy for formation was 231 ± 42 kJ/mol. •Activation energy for decomposition was 792 ± 64 kJ/mol. •Both the formation and decomposition were controlled by diffusion

  6. Calcium channel blockers and Alzheimer's disease★

    Science.gov (United States)

    Tan, Yi; Deng, Yulin; Qing, Hong

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofibrillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers involved in Alzheimer's disease therapy. PMID:25767489

  7. 21 CFR 184.1210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium oxide. 184.1210 Section 184.1210 Food and... Substances Affirmed as GRAS § 184.1210 Calcium oxide. (a) Calcium oxide (CaO, CAS Reg. No. 1305-78-8) is also known as lime, quick lime, burnt lime, or calx. It is produced from calcium carbonate, limestone, or...

  8. Oxalic acid decreases calcium absorption in rats

    International Nuclear Information System (INIS)

    Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.

    1987-01-01

    Calcium absorption from salts and foods intrinsically labeled with 45 Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO 3 and CaCl 2 than from CaC 2 O 4 (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach

  9. Calcium and Nuclear Signaling in Prostate Cancer

    OpenAIRE

    Ivan V. Maly; Wilma A. Hofmann

    2018-01-01

    Recently, there have been a number of developments in the fields of calcium and nuclear signaling that point to new avenues for a more effective diagnosis and treatment of prostate cancer. An example is the discovery of new classes of molecules involved in calcium-regulated nuclear import and nuclear calcium signaling, from the G protein-coupled receptor (GPCR) and myosin families. This review surveys the new state of the calcium and nuclear signaling fields with the aim of identifying the un...

  10. 21 CFR 184.1195 - Calcium citrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium citrate. 184.1195 Section 184.1195 Food and... Substances Affirmed as GRAS § 184.1195 Calcium citrate. (a) Calcium citrate (Ca3(C6H5O7)2·4H2O, CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with...

  11. 21 CFR 184.1185 - Calcium acetate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium acetate. 184.1185 Section 184.1185 Food and... Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be...

  12. 21 CFR 184.1229 - Calcium stearate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium stearate. 184.1229 Section 184.1229 Food... Specific Substances Affirmed as GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared as...

  13. Calcium Balance in Chronic Kidney Disease.

    Science.gov (United States)

    Hill Gallant, Kathleen M; Spiegel, David M

    2017-06-01

    The kidneys play a critical role in the balance between the internal milieu and external environment. Kidney failure is known to disrupt a number of homeostatic mechanisms that control serum calcium and normal bone metabolism. However, our understanding of calcium balance throughout the stages of chronic kidney disease is limited and the concept of balance itself, especially with a cation as complex as calcium, is often misunderstood. Both negative and positive calcium balance have important implications in patients with chronic kidney disease, where negative balance may increase risk of osteoporosis and fracture and positive balance may increase risk of vascular calcification and cardiovascular events. Here, we examine the state of current knowledge about calcium balance in adults throughout the stages of chronic kidney disease and discuss recommendations for clinical strategies to maintain balance as well as future research needs in this area. Recent calcium balance studies in adult patients with chronic kidney disease show that neutral calcium balance is achieved with calcium intake near the recommended daily allowance. Increases in calcium through diet or supplements cause high positive calcium balance, which may put patients at risk for vascular calcification. However, heterogeneity in calcium balance exists among these patients. Given the available calcium balance data in this population, it appears clinically prudent to aim for recommended calcium intakes around 1000 mg/day to achieve neutral calcium balance and avoid adverse effects of either negative or positive calcium balance. Assessment of patients' dietary calcium intake could further equip clinicians to make individualized recommendations for meeting recommended intakes.

  14. 21 CFR 184.1193 - Calcium chloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium chloride. 184.1193 Section 184.1193 Food... Specific Substances Affirmed as GRAS § 184.1193 Calcium chloride. (a) Calcium chloride (CaCl2·2H2O, CAS Reg. No. 10035-04-8) or anhydrous calcium chloride (CaCl2, CAS Reg. No. 10043-52-4) may be commercially...

  15. The Electronic Structure of Calcium

    DEFF Research Database (Denmark)

    Jan, J.-P.; Skriver, Hans Lomholt

    1981-01-01

    The electronic structure of calcium under pressure is re-examined by means of self-consistent energy band calculations based on the local density approximation and using the linear muffin-tin orbitals (LMTO) method with corrections to the atomic sphere approximation included. At zero pressure...

  16. The impact of calcium assay change on a local adjusted calcium equation.

    Science.gov (United States)

    Davies, Sarah L; Hill, Charlotte; Bailey, Lisa M; Davison, Andrew S; Milan, Anna M

    2016-03-01

    Deriving and validating local adjusted calcium equations is important for ensuring appropriate calcium status classification. We investigated the impact on our local adjusted calcium equation of a change in calcium method by the manufacturer from cresolphthalein complexone to NM-BAPTA. Calcium and albumin results from general practice requests were extracted from the Laboratory Information Management system for a three-month period. Results for which there was evidence of disturbance in calcium homeostasis were excluded leaving 13,482 sets of results for analysis. The adjusted calcium equation was derived following least squares regression analysis of total calcium on albumin and normalized to the mean calcium concentration of the data-set. The revised equation (NM-BAPTA calcium method) was compared with the previous equation (cresolphthalein complexone calcium method). The switch in calcium assay resulted in a small change in the adjusted calcium equation but was not considered to be clinically significant. The calcium reference interval differed from that proposed by Pathology Harmony in the UK. Local adjusted calcium equations should be re-assessed following changes in the calcium method. A locally derived reference interval may differ from the consensus harmonized reference interval. © The Author(s) 2015.

  17. Absorbability of calcium from calcium-bound phosphoryl oligosaccharides in comparison with that from various calcium compounds in the rat ligated jejunum loop.

    Science.gov (United States)

    To-o, Kenji; Kamasaka, Hiroshi; Nishimura, Takahisa; Kuriki, Takashi; Saeki, Shigeru; Nakabou, Yukihiro

    2003-08-01

    Calcium-bound phosphoryl oligosaccharides (POs-Ca) were prepared from potato starch. Their solubility and in situ absorbability as a calcium source were investigated by comparing with the soluble calcium compounds, calcium chloride and calcium lactate, or insoluble calcium compounds, calcium carbonate and dibasic calcium phosphate. The solubility of POs-Ca was as high as that of calcium chloride and about 3-fold higher than that of calcium lactate. An in situ experiment showed that the intestinal calcium absorption rate of POs-Ca was almost comparable with that of the soluble calcium compounds, and was significantly higher (pcalcium groups. Moreover, the total absorption rate of a 1:1 mixture of the calcium from POs-Ca and a whey mineral complex (WMC) was significantly higher (psoluble calcium source with relatively high absorption in the intestinal tract.

  18. 21 CFR 582.1210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium oxide. 582.1210 Section 582.1210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1210 Calcium oxide. (a) Product. Calcium oxide. (b) Conditions of use. This substance is generally...

  19. 21 CFR 582.5210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium oxide. 582.5210 Section 582.5210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5210 Calcium oxide. (a) Product. Calcium oxide. (b) Conditions of use. This substance is...

  20. Lactulose stimulates calcium absorption in postmenopausal women

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muijs, T.; Dokkum, W. van; Schaafsma, G.

    1999-01-01

    Animal studies have indicated that calcium absorption is increased by lactulose, a synthetic disaccharide. Therefore, the influence of lactulose on calcium absorption was measured in postmenopausal women who may benefit from the possible enhancing effect of lactulose on calcium absorption. Twelve