bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of multigrooved surfaces on osteoblast‐like cells in vitro: Scanning electron microscopic observation and mRNA expression of osteopontin and osteocalcin
Authors: Matsuzaka K. , Yoshinari M. , Shimono M. , Inoue T. 
Published: December 2003

AbstractThis study evaluated the behavior of osteoblast‐like cells on multigrooved surfaces consisting of a combination of microgrooves and macrogrooves. A polystyrene substrate was fabricated with multigrooves with 90‐degree, V‐shaped microgrooves with a 2‐μm pitch cut on trapezoidal macrogrooves, which had a 50‐μm ridge width, a 50‐μm wall width, a 50‐μm bottom width, and 25‐μm depth. Smooth polystyrene substrates were also prepared as controls. Rat bone marrow cells were cultured as osteoblast‐like cells on the substrates for morphological evaluation using a scanning electron microscope, and for biochemical evaluation using the quantitative reverse transcriptase‐polymerase chain reaction technique for osteopontin and osteocalcin mRNA expression. After 8 days of incubation, the osteoblast‐like cells were aligned parallel to the surface grooves on the multigrooved substrates. After 16 days of incubation, a dense mineralized extracellular matrix (ECM) was produced along the multigrooves. The ECM on the multigrooved surface appeared oriented more in the direction of the grooves than on the smooth surface, and trapezoid‐shaped macrogrooves of the ECM were cast upside down. Although there were not significant differences, the osteopontin and osteocalcin mRNA expressions of the osteoblast‐like cells on the multigrooved surfaces tended to be higher than on smooth surfaces. These results suggest that multigrooves could be used to control the orientation of mineralized ECM as well as of cells, and also to enhance the production of mineralized ECM. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 227–234, 2004
Immobilized concentration gradients of nerve growth factor guide neurite outgrowth
Authors: Kapur Terri Adams , Shoichet Molly S. 
Published: December 2003

AbstractAxons are guided to their targets by a combination of haptotactic and chemotactic cues. We previously demonstrated that soluble neurotrophic factor concentration gradients guide axons in a model system. In an attempt to translate this model system to a device for implantation, our goal was to immobilize a stable neurotrophic concentration gradient for axonal (or neurite) guidance. Nerve growth factor (NGF) was immobilized within poly(2‐hydroxyethylmethacrylate) [p(HEMA)] microporous gels using a gradient maker. The NGF was stably immobilized, with only ∼0.05% of the amount originally incorporated into the gel released over an 8‐day period. Immobilized NGF was bioactive: the percent of PC12 cells extending neurites on NGF‐immobilized p(HEMA) gels was 16 ± 2%, which was statistically the same as those exposed to soluble NGF (22 ± 6%). We were able to predict and reproducibly create stable NGF concentration gradients in the gel. At an NGF concentration gradient of 357 ng/mL/mm, PC12 cell neurites were guided up the gradient. The facile, flexible, and reproducible nature of this method allowed us to translate soluble growth factor gradient models to stable growth factor gradient devices that may ultimately enhance axonal guidance and regeneration in vivo. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 235–243, 2004
Substrate‐dependent cellular behavior of Swiss 3T3 fibroblasts and activation of Rho family during adhesion and spreading processes
Authors: Kato Shinya , Kidoaki Satoru , Matsuda Takehisa 
Published: December 2003

AbstractRecent biochemical studies revealed that intracellular Rho guanosine triphosphatases (Rho, Rac1, and Cdc42) are key regulatory molecules that link surface receptors to cytoskeletal organization and regulation of cell shape/morphology/motility. In this study, Swiss 3T3 fibroblasts were cultured on three representative substrates [tissue culture polystyrene dishes, nontreated polystyrene, and poly(ethylene terephthalate)] for 24 h after plating. Time‐dependent changes in cell shape, morphology, cytoskeletal dynamics, and motility as well as Rho family activities were determined on each substrate. The cells on tissue culture polystyrene and on poly(ethylene terephthalate), which induced rapid and relatively rapid cell spreading, respectively, expressed Rac1 and Cdc42 activities continuously during the observation period. In contrast, such activities were suppressed in cells on polystyrene, which induced slow spreading but the highest cell motility compared with the other two substrates. Although a clear‐cut relationship between cellular behavior and Rho family activation was not obtained, substrate‐dependent coordinated control of cellular activities by Rho family is discussed. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 314–324, 2004
Cytotoxicity evaluation of ceramic particles of different sizes and shapes
Authors: Yamamoto Akiko , Honma Rieko , Sumita Masae , Hanawa Takao 
Published: December 2003

AbstractWhen artificial hip or knee joints are implanted in the human body, they release metallic, ceramic, and polymeric debris into the surrounding tissues. The toxicity of the released particles is of two types: chemical, caused by the released soluble ions and monomers, and mechanical, a result of mechanical stimulation produced by the insoluble particles. In this study, the cytotoxicity of particles of TiO2, Al2O3, ZrO2, Si3N4, and SiC for murine fibroblasts and macrophages were examined to evaluate just their mechanical toxicity because these particles are not expected to release soluble metal ions. Different sizes and shapes of TiO2 particles were used to evaluate the effect of size and shape on particle cytotoxicity. The results suggest that the cytotoxicity of ceramic particles does not depend on their chemical species. Cytotoxicity levels were lower than those of corresponding metal ions, indicating that the mechanical toxicity of particles is lower than the chemical toxicity of released soluble ions and monomers. The differences in size did not affect the mechanical toxicity of these particles. The dendritic particles had a higher cytotoxicity level for macrophages than did spindle and spheric particles. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 244–256, 2004
Fibronectin interactions with osteoblasts: Identification of a non–integrin‐mediated binding mechanism using a real‐time fluorescence binding assay
Authors: Sim Bushra , Cladera Josep , O'Shea Paul 
Published: December 2003

AbstractFibronectin (Fn) is an extracellular matrix protein that interacts with specific integrins on the cell surface, initiating signal transduction processes that lead to a reorganization of the cytoskeleton and the assembly of focal adhesions. Cell surface proteoglycans or glycosaminoglycans (GAGs) such as heparan sulfate are also known to participate in the interaction of Fn with the cell surface by binding to two different heparin‐binding domains. The influence of Fn and GAGs on the spreading and differentiation of human osteoblasts was also previously described. In the current work, a method developed in our laboratory is established to evaluate the interaction between Fn and human osteoblasts and the influence of GAGs on such interactions. This technique makes use of fluoresceinphosphatidylethanolamine (FPE) such that when inserted into the lipidic bilayer, it acts as a fluorescent indicator of membrane interactions. The results indicate that the binding profile of Fn with the osteoblast cell surface is best represented by a hyperbolic single binding site model with a membrane affinity of 120 nM. Removal of cell surface heparan sulfate by treatment with heparitinase indicates that the cell surface moiety is directly involved in the binding process. Studies directed to assess the influence of heparin on the interaction of Fn with osteoblasts reveal that although it does not hamper Fn binding to the cell surface, it blocks the initial attachment to Fn‐coated surfaces, indicating that binding to the integrin receptor alone is not enough to promote cell attachment but that the participation of the cell‐surface GAGs is also a necessary condition. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 352–359, 2004
Gingival organotypic culture and langerhans cells: A tool for immunotoxicologic experiments
Authors: Lamarque Stéphane , Pellen‐Mussi Pascal , Rougier Nathalie , Le Lan Jacky , Chesne Christophe , Bonnaure‐Mallet Martine 
Published: December 2003

AbstractLangerhans cells (LCs) are dendritic cells localized in epidermis and mucosal tissues, where they are responsible for triggering the immune response. To study LCs in the oral epithelium, organotypic cultures were prepared using gingival explants. Immunochemical techniques using anti‐CD1a, anti‐HLA‐DR, and anti‐Langerin antibodies were used to detect and quantify LCs at various times. Observations were made by light and confocal microscopy. Quantification studies showed that there is a statistically significant drop in LC numbers in the epithelial tissue after 96 h of incubation. Gingival organotypic cultures thus are a good model for studying the migration of LCs and their involvement in contact hypersensitivity and periodontal diseases. The model offers potential utility as a tool for the study of periodontal tissue in the presence of different stimuli and for conducting immunotoxicologic experiments. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 257–263, 2004
Use of an intramedullary in vivo model to study bone formation and maintenance in ceramic porous domains
Authors: Pabbruwe Moreica B. , Standard Owen C. , Sorrell Charles. C. , Howlett C. Rolfe 
Published: December 2003

AbstractTissue ingrowth, differentiation, and osteogenesis in a porous bioinert bioceramic were studied using an intramedullary model. Pure alumina tubes (1.3 mm outer diameter, 0.6 mm inner diameter, 15 mm length) were implanted in the femoral medullary canal of young female rats for 4, 6, 8, 12, and 16 weeks. Tissues present within each tube were characterized by histology and quantified by histomorphometry. A tissue front consisting of undifferentiated mesenchymal cells, fibrovascular tissue, osteoid, woven bone, and marrow penetrated the tube from both ends. Behind the front, woven bone remodeled to produce a thin layer of lamellar bone that lined the tube walls the entire distance to the tube ends and enclosed a marrow‐filled lumen. The front was considered to represent the differentiation cascade from mesenchymal cells to fibrovascular tissue to osteoid to woven bone and marrow to lamellar bone and marrow. The fronts advanced into the tube with time such that, by 16 weeks, they were close to meeting or had met. In several instances, the tube was completely lined with a thin layer of mature lamellar bone continuous between the two ends and enclosing marrow. This configuration was considered to be the final equilibrium of tissues within the tube. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 305–313, 2004
Peripheral nerve regeneration by microbraided poly(L‐lactide‐co‐glycolide) biodegradable polymer fibers
Authors: Bini T. B. , Gao Shujun , Xu Xiaoyun , Wang Shu , Ramakrishna S. , Leong Kam. W. 
Published: December 2003

AbstractTiny tubes with fiber architecture were developed by a novel method of fabrication upon introducing some modification to the microbraiding technique, to function as nerve guide conduit and the feasibility of in vivo nerve regeneration was investigated through several of these conduits. Poly(L‐lactide‐co‐glycolide) (10:90) polymer fibers being biocompatible and biodegradable were used for the fabrication of the conduits. The microbraided nerve guide conduits (MNGCs) were characterized using scanning electron microscopy to study the surface morphology and fiber arrangement. Degradation tests were performed and the micrographs of the conduit showed that the degradation of the conduit is by fiber breakage indicating bulk hydrolysis of the polymer. Biological performances of the conduits were examined in the rat sciatic nerve model with a 12‐mm gap. After implantation of the MNGC to the right sciatic nerve of the rat, there was no inflammatory response. One week after implantation, a thin tissue capsule was formed on the outer surface of the conduit, indicating good biological response of the conduit. Fibrin matrix cable formation was seen inside the MNGC after 1 week implantation. One month after implantation, 9 of 10 rats showed successful nerve regeneration. None of the implanted tubes showed tube breakage. The MNGCs were flexible, permeable, and showed no swelling apart from its other advantages. Thus, these new poly(L‐lactide‐co‐glycolide) microbraided conduits can be effective aids for nerve regeneration and repair and may lead to clinical applications. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 286–295, 2004
Osteointegration of bioactive glass‐coated and uncoated zirconia in osteopenic bone: An in vivo experimental study
Authors: Aldini N. Nicoli , Fini M. , Giavaresi G. , Martini L. , Dubini B. , Bossi M. G. Ponzi , Rustichelli F. , Krajewski A. , Ravaglioli A. , Mazzocchi M. , Giardino R. 
Published: December 2003

AbstractIn elderly and osteoporotic patients an age‐related loss of osteoinductivity could be the biological cause of implant failure regardless of the high quality of the implanted device. yttria stabilized tetragonal zirconia (YSTZ), either coated with the bioactive glass named RKKP bioglaze® (RKKP) or uncoated, was implanted in the distal femurs of sham‐operated and ovariectomized female rats. Animals were sacrificed at 30 and 60 days. Histomorphometry and microhardness tests were performed to assess osteointegration rate as well as bone quality around the implants. Significant decreases (p < 0.0005) in trabecular bone volume, BV/TV (41%), trabecular bone surface BS/TV (33%), trabecular thickness Tb.Th (20%), and trabecular number Tb.N (32%), together with a significant increase in trabecular separation Tb.Sp (184%), were found for the osteopenic rats compared with the sham‐operated rats. At both experimental times the RKKP coating ensured a better osteointegration rate with higher AI values than the uncoated YSTZ, even when osteopenic rats were used (48% at 30 days and 12% at 60 days). No differences were observed at the bone‐biomaterial interfaces for either material when comparing sham‐operated with osteopenic rats. The present results demonstrate that the RKKP bioactive glass used as a coating ensures a high osteointegration rate even in osteoporotic bone, which is already visible from postoperative day 30 and is still apparent on day 60. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 264–272, 2004
Ultrastructure and nanomechanical properties of cementum dentin junction
Authors: Ho S. P. , Balooch M. , Goodis H. E. , Marshall G. W. , Marshall S. J. 
Published: December 2003

AbstractThe attachment between cementum and dentin has been given several definitions and nomenclature, including: interzonal layer, intermediate cementum, collagen hiatus, Hopewell‐Smith's hyaline layer, and more commonly, cementum–dentin junction (CDJ). Understanding the attachment of two structurally dissimilar hard tissues such as cementum and dentin defined by a junction may provide information necessary to engineer functionally graded materials that can be used for efficient tooth restorations in clinical dentistry and other bioengineering applications. Hence, in this study, as a first step toward understanding the CDJ using a biomechanical approach, it was hypothesized that the CDJ between cementum and dentin is a wide zone with mechanical properties significantly lower than the neighboring tissues. The structure of the CDJ was studied using an atomic force microscope (AFM), and site‐specific mechanical response of the three regions; cementum, CDJ, and dentin were determined using an AFM‐nanoindenter under dry and wet conditions. The AFM results of the CDJ demonstrated a valley under dry conditions and a peak under wet conditions. The magnitude of the depth of the valley was approximately the same as the height of the peak of the CDJ, ranging from 10 to 40 μm. The nanomechanical properties under dry conditions indicated no significant difference (p > 0.05) in elastic modulus and hardness of the CDJ (Er = 17.5 ± 2.7 GPa, H = 0.6 ± 0.1 GPa) and cementum (Er = 18.7 ± 2.5 GPa, H = 0.6 ± 0.1 GPa). The mechanical properties of the CDJ were significantly lower (p ≪ 0.05) than dentin (Er = 19.9 ± 2.9 GPa, H = 0.6 ± 0.1 GPa) under dry conditions. However, under more relevant hydrated conditions, the mechanical properties of CDJ (Er 3.0 ± 0.7 GPa, H = 0.1 ± 0.0 GPa) were significantly lower (p ≪ 0.05) than those of cementum (Er 6.8 ± 1.9 GPa, H = 0.2 ± 0.1 GPa) and dentin (Er 9.4 ± 2.3 GPa, H = 0.3 ± 0.1 GPa). Based on the results from this study, it can be concluded that the CDJ can be regarded as a wide zone containing large quantities of proteins including collagen that contribute to hydration and significantly reduce mechanical properties, compared with the adjacent hard tissues, cementum, and dentin. The lower mechanical properties of the CDJ may make it possible for it to redistribute occlusal loads to the alveolar bone. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 343–351, 2004
Surface analyses of micro‐arc oxidized and hydrothermally treated titanium and effect on osteoblast behavior
Authors: Zhang Y. M. , Bataillon‐Linez P. , Huang P. , Zhao Y. M. , Han Y. , Traisnel M. , Xu K. W. , Hildebrand H. F. 
Published: December 2003

AbstractOsteoblast adhesion on the implant material surface is essential for the success of any implant in which osteointegration is required. Surface properties of implant material have a critical role in the cell adhesion progress. Titanium and its alloys are widespread and increasingly used as implant material in dentistry and orthopedics because of their excellent biocompatibility, which is attributed to a passive layer of TiO2 on the surface. In this study, the micro‐arc oxidizing (MAO) and hydrothermally synthesizing (HS) methods were used to modify the TiO2 layer on the titanium surface. The surface microstructure was observed by scanning electron microscopy. The surface energy was assessed. The mouse osteoblastic cell line (MC3T3‐E1) was seeded on the treated surfaces to evaluate their effect on cell behavior. This included cell adhesion kinetics, cell proliferation, cell morphology, and cytoskeletal organization. The surface structure of MAO samples exhibited micropores with a diameter of 1–3 μm, whereas the MAO–HS‐treated samples showed additional multiple crystalline microparticles on the microporous surface. The surface energy of MAO and MAO–HS was higher than that of titanium. The cell adhesion rate was higher on the MAO–HS surface than on the MAO and titanium surface, but without any significant difference between them. After 3 days of culture, cells proliferated significantly more on the MAO and titanium surface than on the MAO–HS surface. The cytoskeletal organization was analyzed by actin and vinculin staining on all the samples. We conclude that the MAO and MAO–HS methods change the surface energy of TiO2 layer on the titanium surface. This may have an influence on the initial cell attachment. Other surface characteristics may be involved in the cell proliferation, which is different from cell attachment on the sample surface. A longer‐duration cell experiment should be conducted to see the effect on cell differentiation. Future in vivo evaluation may give further evidence to optimize the surface character of this kind of implant material. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 383–391, 2004
Gene expression changes in BALB/3T3 transformants induced by poly(L‐lactic acid) or polyurethane films
Authors: Matsuoka Atsuko , Tsuchiya Toshie 
Published: December 2003

AbstractWe performed DNA microarray analysis on two BALB/3T3 transformants (A5 and A6) induced by polyurethane (PU) film, two (L11 and L21) induced by biodegradable poly(L‐lactic acid) (PLLA) film, and the parental cells. The transforming ability of the cells was in the order A5 < A6 < L21 < L11. In all, 1176 cancer‐related genes were up‐ or down‐regulated in at least one transformant. Those that were markedly up‐regulated were c‐fos protooncogene, FBJ osteosarcoma oncogene B, and Jun oncogene; those markedly down‐regulated were pleiotrophin, histidine triad nucleotide‐binding protein, protein kinase C iota, and large multifunctional protease 7. A common function of proteins encoded by genes that underwent marked expression changes was bone formation. The genes were c‐fos, FBJ osteosarcoma, Jun, pleiotrophin, a disintegrin‐like and metalloprotease with TS‐1 motif protein 1. This finding was consistent with the tumor formation in the 2‐year PLLA or PU subcutaneous implantation into rats. The number of genes that underwent marked expression change in each transformant was consistent with its malignancy. PLLA induced more malignant transformants than PU, especially in relation to osteosarcoma‐like gene expression. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 376–382, 2004
Tissue adhesiveness and host response of in situ photopolymerizable interpenetrating networks containing methylprednisolone acetate
Authors: Zilinski Jodi L. , Kao Weiyuan John 
Published: December 2003

AbstractInterpenetrating networks (IPNs) of varying formulations were investigated as candidates for an in situ photopolymerizable drug delivery matrix containing poly(ethylene glycol) diacrylate and gelatin. The anti‐inflammatory agent methylprednisolone acetate was loaded into the IPN. Bond strength between the IPN and tissue (i.e., muscle, dermis, skin) was determined by a modified American Society for Testing and Materials peel test at constant peel rate. The IPNs provided adhesion values of up to 5.7N, which were three‐ to fivefold lower than that of the commercial tissue bioadhesive. The subcutaneous cage implant system was utilized to assess material host response and drug efficacy in vivo. IPN formulations elicited a more intense acute inflammatory response than the empty cage controls. Methylprednisolone acetate loaded within the IPNs lowered the level of inflammatory response to levels that were comparable to the empty cage baseline controls. In conclusion, a methodology was developed to quantify the tissue adhesiveness of an in situ photopolymerized IPN matrix containing anti‐inflammatory agents. The efficacy of drug‐loaded IPN in affecting the host inflammatory response was demonstrated in vivo. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 392–400, 2004
Administration of bone marrow cells into surgically induced fibrocollagenous tunnels induces angiogenesis in ischemic rat hindlimb model
Authors: Padilla Luis , Krötzsch Edgar , Schalch Paul , Figueroa Siegfried , Miranda Adriana , Rojas Enrique , Esperante Sandro , Villegas Fernando , De La Garza Anabel S. , Di Silvio Mauricio 
Published: December 2003

AbstractWe established a comparative model of angiogenic induction in previously formed fibrocollagenous tunnels in rat inner thigh muscles. A unilateral hindlimb chronic ischemia model was performed in male Sprague‐Dawley rats. A device was then inserted in the central portion of the inner thigh muscles. Vascularity in the ischemic limb was determined by means of an angiographic score, capillary/fiber ratio, and endothelial proliferation by histochemistry and immunohistochemistry. Autologous transplant of bone marrow, vascular endothelial growth factor (VEGF), or collagen‐polyvinylpyrrolidone plus heparin induced significant vascularization of the ischemic hindlimb when compared to saline solution. However, the bone marrow group presented a higher angiographic score than the other two. No differences among groups were observed in capillary/fiber ratio or proliferation, except for the VEGF group, where capillary proliferating cells were significantly higher than in controls. Based on these results, bone marrow‐derived progenitor cells may constitute a safe and viable alternative for the induction of therapeutic angiogenesis. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:568–574 2003