bluuebunny/crossref_metadata_2025_split huggingface dataset:
A completely autologous valved conduit prepared in the open form of trileaflets (type VI biovalve): Mold design and valve function in vitro
Authors: Nakayama Yasuhide , Yahata Yuki , Yamanami Masashi , Tajikawa Tsutomu , Ohba Kenkichi , Kanda Keiichi , Yaku Hitoshi 
Published: June 2011

AbstractIn‐body tissue, architecture technology represents a promising approach for the development of living heart valve replacements and preparation of a series of biovalves. To reduce the degree of regurgitation and increase the orifice ratio, we designed a novel mold for a type VI biovalve. The mold had an outer diameter of 14 mm for implantation in beagles, and it was prepared by assembling two silicone rods with a small aperture (1 mm) between them. One rod had three protrusions of the sinus of Valsalva, whereas the other was almost cylindrical. When the molds were embedded in the subcutaneous pouches of beagles for 1 month, the native connective tissues that subsequently developed covered the entire outer surface of the molds and migrated into the aperture between the rods. The mold from both sides of the harvested cylindrical implant was removed, and homogenous well‐balanced trileaflets were found to be separately formed in the open form with a small aperture at the three commissure parts inside the developed conduit, which had a thick homogenous wall even in the sinus of Valsalva. Exposure of the obtained biovalves to physiological aortic valve flow in beagles revealed proper opening motion with a wide orifice area. The closure dynamics were suboptimal, probably due to the reduction in the size of the sinus of Valsalva. The mechanical behavior of this biovalve might allow its use as a living aortic valve replacement. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Development and in vitro studies of a polyethylene terephthalate‐gold nanoparticle scaffold for improved biocompatibility
Authors: Whelove Ona E. , Cozad Matthew J. , Lee Byung‐Doo , Sengupta Shramik , Bachman Sharon L. , Ramshaw Bruce J. , Grant Sheila A. 
Published: June 2011

AbstractPolyethylene terephthalate (PET) mesh is one of the most commonly used synthetic biomaterials for tension‐free hernia repair. In an effort to improve the biocompatibility of PET mesh, gold nanoparticles (AuNP) in various concentrations were conjugated to the PET surface to develop PET‐AuNP scaffolds. These novel scaffolds were characterized with Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) to assess the addition of functional groups, presence of AuNPs, and thermal stability of the modified PET mesh, respectively. The biocompatibility of the PET‐AuNP scaffolds was evaluated through in vitro cell culture assays. The cellularity of cells exposed to the PET‐AuNP scaffolds, as well as the scaffolds' ability to reduce reactive oxygen species, was assessed using L929 murine fibroblasts. Antimicrobial properties of AuNPs conjugated to PET mesh were tested against the bacteria Pseudomonas aeruginosa. Results from the FT‐IR showed presence of COOH groups while SEM displayed bonding of AuNPs to the PET surface. DSC results indicated that the PET more than likely did not undergo any detrimental degradation due to the surface modification. Results from the in vitro studies showed that AuNPs, in optimal concentrations (1× concentrations), enhanced cellularity, reduced ROS, and reduced bacteria adhesion to PET. These studies demonstrated enhanced biocompatibility of the AuNP conjugated PET mesh over pristine PET mesh. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Synthesis of spherical hydroxyapatite granules with interconnected pore channels using camphene emulsion
Authors: Yang Jung‐Ho , Kim Kyo‐Han , You Chang‐Kook , Rautray Tapash R. , Kwon Tae‐Yub 
Published: June 2011

AbstractThe aim of this study was to fabricate porous spherical hydroxyapatite (HA) granules with interconnected pore channels for use as a bone graft substitute. Various weights of camphene porogen were mixed with nano‐sized HA powder (camphene/HA = 0, 10, 30, 50, 70, and 90% w/w) and 10% gelatin aqueous solution then added to the mixture. The water‐in‐oil emulsion method was employed to obtain spherical‐shaped granules, of which those 1000–2000 μm in diameter were selectively classified using a standard sieve set. Thermogravimetric analysis and X‐ray diffraction were used to determine optimal sintering conditions. The sintered granules were characterized using field emission‐scanning electron microscopy (FE‐SEM), microcomputed tomography, and porosimetry. The pore size and porosity of spherical HA granules increased with the addition of camphene. Granules with a HA/camphene ratio of 90% (HG90) demonstrated macropores (>50 μm) with interconnected pore channels (porosity: 58.49%). In addition, FE‐SEM examination of HG90 coated with polycaprolactone showed that the granule may hold promise as a drug delivery carrier. We concluded that these HG90 granules merit consideration as a bone graft substitute or drug delivery carrier in bone tissue engineering. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Experimental and computational models to investigate the effect of adhesion on the mechanical properties of bone‐cement composites
Authors: Helgason B. , Stirnimann P. , Widmer R. , Ferguson S. J. 
Published: June 2011

AbstractA generic finite element approach was developed to study the effect of adhesion on the mechanical response of bone cement composites and validated against literature data. The results showed that a zero friction bone‐cement (PMMA) interface conditions captured the results of the experimental testing better than assuming a fully bonded interface. An experimental model for studying the effect of interface adhesion in a bone‐cement like composite was also developed in the present study. The results using this model indicate that the difference in Young's modulus and ultimate strength between a fully bonded interface and unbonded interface is approximately 30% for bone volume fraction similar to what can be found in osteoporotic vertebrae. Apart from concluding that bone to cement adhesion is a major contributor to the mechanical response of bone‐cement composites, our studies based on the generic FE approach also indicate that the mechanical properties of the cement is the most important contributor to the resulting mechanical properties of the composite at bone volume fraction relevant in terms of vertebroplasty treatment. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Neomycin enhances extracellular matrix stability of glutaraldehyde crosslinked bioprosthetic heart valves
Authors: Friebe Vincent M. , Mikulis Brandon , Kole Sourav , Ruffing Christy S. , Sacks Michael S. , Vyavahare Naren R. 
Published: June 2011

AbstractGlutaraldehyde (GLUT) crosslinked porcine aortic heart valves are continued to be extensively used in heart valve replacement surgeries. GLUT does not crosslink glycosaminoglycans in the tissue and we have demonstrated that GAG loss is associated with tissue degeneration. In this study, we examined the ability of neomycin to enhance GLUT crosslinking to stabilize GAGs, as well as provide evidence of improved functional integrity. Neomycin enhanced GLUT crosslinked (NG) leaflets exposed to collagenase and elastase enzymes exhibited an increased resistance to proteolytic degradation. Furthermore, NG leaflets exhibited small but significant increases in collagen denaturation temperatures when compared to that of standard GLUT crosslinked BHVs. NG leaflets subjected to storage, accelerated cyclic fatigue, and in vitro enzyme mediated GAG degradation revealed improved GAG stabilization versus standard GLUT crosslinked valves, which sustained substantial decreases in GAG content. Ultrastructural analysis using transmission electron microscopy qualitatively confirmed NG leaflets preserved GAGs after enzymatic degradation. Biomechanical analyses demonstrated that NG leaflets were functionally similar to GLUT tissues but were slightly stiffer under both planar biaxial tension and under flexure. Interestingly, after GAGase treatment, GLUT tissues showed increased areal compliance and reduced hysteresis, while NG leaflets were unchanged. Collectively, NG cross‐linking functionally insulated the tissue from GAG digestion, and imparted modest additional matrix stiffness but maintained tissue hysteresis properties. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
A synthesis route to nanoparticle dicalcium silicate for biomaterials research
Authors: Booncharoen W. , Jaroenworaluck A. , Stevens R. 
Published: June 2011

AbstractDicalcium silicate (Ca2SiO4) has been reported as an interesting candidate for biomaterials use due to its attractive bioactive properties. Here, we report on how dicalcium silicate was prepared by a sol–gel route using calcium nitrate tetrahydrate and tetraorthosilicate as the precursors chemicals for CaO and SiO2, respectively. The synthesized powders were characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), Brunauer‐Emmett‐Teller (BET) method, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). High purity dicalcium silicate at a CaO/SiO2 molar ratio of 2:1 could be formed by the sol–gel method without a washing process and was then calcined at 800°C. The effects of the molar ratio of CaO/SiO2, the washing process, and the calcination temperature have been shown to affect the purity, the formation, and the particle size of the nanoparticles, which have been investigated and discussed. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Corrosion of Mg alloy AZ91D in the presence of living cells
Authors: Seuss F. , Seuss S. , Turhan M. C. , Fabry B. , Virtanen S. 
Published: June 2011

AbstractMg and Mg alloys are of interest for biodegradable implants as they readily corrode in biological fluids, and dissolved Mg ions are nontoxic. Even though it is well known that Mg dissolution leads to pH increase in the surroundings, the effect of the corrosion‐induced alkalization on the biological environment has not been studied in detail. We therefore explored the interactions between corrosion‐induced pH increase and cell growth on Mg alloy AZ91D surface. Cell adhesion and spreading on the alloy surface is unimpeded initially. However, with time a large fraction of cells de‐adhere. We attribute this to the observed increase of the pH in the cell culture medium in the process of alloy dissolution. Cytotoxicity tests with HeLa cells grown on glass surfaces confirm that cell death increases with increasing alkalinity of the cell culture medium. We also show that a the cells that adhere on the Mg alloy surface act as a corrosion‐blocking surface layer. In consequence, a slower pH increase in the medium takes place when the alloy surface is covered with cells. Electrochemical impedance spectroscopy measurements (EIS) verify that a cell layer slows down the corrosion process. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Uncertainties in the prevention and treatment of glucocorticoid-induced osteoporosis
Authors: Hansen Karen E , Wilson H Alexander , Zapalowski Carol , Fink Howard A , Minisola Salvatore , Adler Robert A 
Published: June 2011

Abstract
Much knowledge has accrued since the 2001 American College of Rheumatology (ACR) guidelines were published to assist clinicians in the prevention and treatment of glucocorticoid-induced osteoporosis (GIO). Therefore, the ACR undertook a comprehensive effort to review the literature and update the GIO guidelines [Grossman JM, Gordon R, Ranganath VK, et al. American College of Rheumatology 2010 recommendations for the prevention and treatment of glucocorticoid-induced osteoporosis. Arthritis Care Res (Hoboken). 2010;62:1515–1526]. Herein, we review the new guidelines for JBMR readers, highlighting the changes introduced by the 2010 publication. We discuss several patient scenarios for which the new treatment guidelines do not apply, or for which our committee interprets existing literature differently and suggests an alternative approach. © 2011 American Society for Bone and Mineral Research
Effects of antiresorptive treatment on nonvertebral fracture outcomes
Authors: Mackey Dawn C , Black Dennis M , Bauer Douglas C , McCloskey Eugene V , Eastell Richard , Mesenbrink Peter , Thompson John R , Cummings Steven R 
Published: June 2011

Abstract
Various definitions of nonvertebral fracture have been used in osteoporosis trials, precluding comparisons of efficacy. Using only subgroups of nonvertebral fractures for trial outcomes may underestimate the benefits and cost-effectiveness of treatments. The objectives of this study were to determine (1) the effect of antiresorptive treatment on various nonvertebral fracture outcomes, (2) whether risk reduction from antiresorptive treatment is greater for nonvertebral fractures that have stronger associations with low BMD, and (3) sample size estimates for clinical trials of osteoporosis treatments. Study-level data were combined from five randomized fracture-prevention trials of antiresorptive agents that reduce the risk of nonvertebral fracture in postmenopausal women: alendronate, clodronate, denosumab, lasofoxifene, and zoledronic acid. Pooled effect estimates were calculated with random-effects models. The five trials included 30,118 women; 2997 women had at least one nonvertebral fracture. There was no significant heterogeneity between treatments for any outcome (all p &gt; 0.10). Antiresorptive treatment had similar effects on all fractures (summary hazard ratio [HR] = 0.76, 95% CI 0.70–0.81), high-trauma fractures (HR = 0.74, 95% CI 0.57–0.96), low-trauma fractures (HR = 0.77, (95% CI 0.71–0.83), nonvertebral six (ie, hip, pelvis, leg, wrist, humerus, and clavicle) fractures (HR = 0.73, 95% CI 0.66–0.80), other than nonvertebral six fractures (HR = 0.78, 95% CI 0.70–0.87), and all fractures other than finger, face, and toe (HR = 0.75, 95% CI 0.70–0.81). Risk reduction was not greater for fractures with stronger associations with low BMD (p = 0.77). A trial of all nonvertebral fractures would require fewer participants (n = 2641 per arm) than one of a subgroup of six fractures (n = 3289), for example. In summary, antiresorptive treatments reduced all nonvertebral fractures regardless of degree of trauma or special groupings, supporting the use of all nonvertebral fractures as a standard endpoint of osteoporosis trials and the basis for estimating the benefits and cost-effectiveness of treatments. © 2011 American Society for Bone and Mineral Research
Impact of oncopediatric dosing regimen of zoledronic acid on bone growth: Preclinical studies and case report of an osteosarcoma pediatric patient
Authors: Battaglia Séverine , Dumoucel Sophie , Chesneau Julie , Heymann Marie-Françoise , Picarda Gaëlle , Gouin François , Corradini Nadège , Heymann Dominique , Redini Françoise 
Published: June 2011

Abstract
Osteosarcoma and Ewing sarcoma represent the two most frequent primary bone tumors that arise in the pediatric population. Despite recent improvement in their therapeutic management, no improvement in survival rate has been achieved since early 1980 s. Among new therapeutic approaches, bisphosphonates are promising candidates as potent inhibitors of bone resorption. However, their effects on bone growth must be studied at dosing regimen corresponding to pediatric protocols. To this aim, several protocols using zoledronic acid (ZOL) were developed in growing mice (50 µg/kg every 2 days × 10). Parameters of bone remodeling and bone growth were investigated by radiography, micro–computed tomography, histology, and biologic analyses. Extramedullar hematopoiesis was searched for in spleen tissue. A transient inhibitory effect of ZOL was observed on bone length, with a bone-growth arrest during treatment owing to an impressive increase in bone formation at the growth plate level (8- to 10-fold increase in BV/TV). This sclerotic band then shifted into the diaphysis as soon as endochondral bone formation started again after the end of ZOL treatment, revealing that osteoclasts and osteoblasts are still active at the growth plate. In conclusion, endochondral bone growth is transiently disturbed by high doses of ZOL corresponding to the pediatric treatment of primary bone tumors. These preclinical observations were confirmed by a case report in a pediatric patient treated in the French OS2006 protocol over 10 months who showed a growth arrest during the ZOL treatment period with normal gain in size after the end of treatment. © 2011 American Society for Bone and Mineral Research
Direct costs of fractures in Canada and trends 1996–2006: A population-based cost-of-illness analysis
Authors: Leslie William D , Metge Colleen J , Azimaee Mahmoud , Lix Lisa M , Finlayson Gregory S , Morin Suzanne N , Caetano Patricia 
Published: June 2011

Abstract
Cost-of-illness (COI) analysis is used to evaluate the economic burden of illness in terms of health care resource (HCR) consumption. We used the Population Health Research Data Repository for Manitoba, Canada, to identify HCR costs associated with 33,887 fracture cases (22,953 women and 10,934 men) aged 50 years and older that occurred over a 10-year period (1996–2006) and 101,661 matched control individuals (68,859 women and 32,802 men). Costs (in 2006 Canadian dollars) were estimated for the year before and after fracture, and the change (incremental cost) was modeled using quantile regression analysis to adjust for baseline covariates and to study temporal trends. The greatest total incremental costs were associated with hip fractures (median $16,171 in women and $13,111 for men), followed by spine fractures ($8,345 in women and $6,267 in men). The lowest costs were associated with wrist fractures ($663 in women and $764 in men). Costs for all fracture types were greater in older individuals (p &lt; 0.001). Similar results were obtained with regression-based adjustment for baseline factors. Some costs showed a slight increase over the 10 years. The largest temporal increase in women was for hip fracture ($13 per year, 95% CI $6–$21, p &lt; 0.001) and in men was for humerus fracture ($11 per year, 95% CI $3–$19, p = 0.007). At the population level, hip fractures were responsible for the largest proportion of the costs after age 80, but the other fractures were more important prior to age 80. We found that there are large incremental health care costs associated with incident fractures in Canada. Identifying COI from HCR use offers a cost baseline for measuring the effects of evidence-based guidelines implementation. © 2011 American Society for Bone and Mineral Research
MafB interacts with Gcm2 and regulates parathyroid hormone expression and parathyroid development
Authors: Kamitani-Kawamoto Akiyo , Hamada Michito , Moriguchi Takashi , Miyai Masashi , Saji Fumie , Hatamura Ikuji , Nishikawa Keizo , Takayanagi Hiroshi , Hitoshi Seiji , Ikenaka Kazuhiro , Hosoya Toshihiko , Hotta Yoshiki , Takahashi Satoru , Kataoka Kohsuke 
Published: June 2011

Abstract
Serum calcium and phosphate homeostasis is critically regulated by parathyroid hormone (PTH) secreted by the parathyroid glands. Parathyroid glands develop from the bilateral parathyroid-thymus common primordia. In mice, the expression of transcription factor Glial cell missing 2 (Gcm2) begins in the dorsal/anterior part of the primordium on embryonic day 9.5 (E9.5), specifying the parathyroid domain. The parathyroid primordium then separates from the thymus primordium and migrates to its adult location beside the thyroid gland by E15.5. Genetic ablation of gcm2 results in parathyroid agenesis in mice, indicating that Gcm2 is essential for early parathyroid organogenesis. However, the regulation of parathyroid development at later stages is not well understood. Here we show that transcriptional activator v-maf musculoaponeurotic fibrosarcoma oncogene homologue B (MafB) is developmentally expressed in parathyroid cells after E11.5. MafB expression was lost in the parathyroid primordium of gcm2 null mice. The parathyroid glands of mafB+/− mice were mislocalized between the thymus and thyroid. In mafB−/− mice, the parathyroid did not separate from the thymus. Furthermore, in mafB−/− mice, PTH expression and secretion were impaired; expression levels of renal cyp27b1, one of the target genes of PTH, was decreased; and bone mineralization was reduced. We also demonstrate that although Gcm2 alone does not stimulate the PTH gene promoter, it associates with MafB to synergistically activate PTH expression. Taken together, our results suggest that MafB regulates later steps of parathyroid development, that is, separation from the thymus and migration toward the thyroid. MafB also regulates the expression of PTH in cooperation with Gcm2. © 2011 American Society for Bone and Mineral Research
Resveratrol promotes osteogenesis of human mesenchymal stem cells by upregulating RUNX2 gene expression via the SIRT1/FOXO3A axis
Authors: Tseng Pei-Chi , Hou Sheng-Mou , Chen Ruey-Jien , Peng Hsiao-Wen , Hsieh Chi-Fen , Kuo Min-Liang , Yen Men-Luh 
Published: June 2011

Abstract
Reports of the bone-protective effects of resveratrol, a naturally occurring phytoestrogen and agonist for the longevity gene SIRT1, have highlighted this compound as a candidate for therapy of osteoporosis. Moreover, SIRT1 antagonism enhances adipogenesis. There has been speculation that resveratrol can promote osteogenesis through SIRT1, but the mechanism remains unclear. In this study we investigated the molecular mechanism of how resveratrol can modulate the lineage commitment of human mesenchymal stem cells to osteogenesis other than adipogenesis. We found that resveratrol promoted spontaneous osteogenesis but prevented adipogenesis in human embryonic stem cell–derived mesenchymal progenitors. Resveratrol upregulated the expression of osteo-lineage genes RUNX2 and osteocalcin while suppressing adipo-lineage genes PPARγ2 and LEPTIN in adipogenic medium. Furthermore, we found that the osteogenic effect of resveratrol was mediated mainly through SIRT1/FOXO3A with a smaller contribution from the estrogenic pathway. Resveratrol activated SIRT1 activity and enhanced FOXO3A protein expression, a known target of SIRT1, in an independent manner. As a result, resveratrol increased the amount of the SIRT1-FOXO3A complex and enhanced FOXO3A-dependent transcriptional activity. Ectopic overexpression or silencing of SIRT1/FOXO3A expression regulated RUNX2 promoter activity, suggesting an important role for SIRT1-FOXO3A complex in regulating resveratrol-induced RUNX2 gene transcription. Further mutational RUNX2 promoter analysis and chromatin immunoprecipitation assay revealed that resveratrol-induced SIRT1-FOXO3A complex bound to a distal FOXO response element (−1269/−1263), an action that transactivated RUNX2 promoter activity in vivo. Taken together, our results describe a novel mechanism of resveratrol in promoting osteogenesis of human mesenchymal stem cells by upregulating RUNX2 gene expression via the SIRT1/FOXO3A axis. © 2011 American Society for Bone and Mineral Research