bluuebunny/crossref_metadata_2025_split huggingface dataset:
A long‐term follow‐up study on the natural course of snus‐induced lesions among Swedish snus users
Authors: Roosaar Ann , Johansson Anna L.V. , Sandborgh‐Englund Gonilla , Nyrén Olof , Axéll Tony 
Published: February 2006

AbstractSnus‐induced lesions (SILs) are mucosal changes that are regularly seen in users of moist snuff (snus). Their role in oral carcinogenesis remains undefined. Our aim was to assess the natural course of SILs over several decades. A cohort of 1,115 individuals with SILs, confirmed in 1973–1974 during a population‐based survey was followed for 27–29 years through multiple record linkages with virtually complete population‐ and health registers. A sample (n = 267) of the cohort members were invited for reexamination after 19–22 years. Register‐based follow‐up through January 2002 revealed a total of 3 incident cases of oral cancer (standardized incidence ratio of 2.3, 95% CI 0.5–6.7), none of which occurred at the site of the original SIL. There was a strong association noted between the degree of SIL and current snus consumption. The SILs had disappeared in all 62 individuals who had permanently quitted using snus. In no case did we observe an important clinical change for the worse among individuals who had decreased their use or continued unabatedly. While the incidence of oral cancer in this cohort of individuals with SILs tended to be higher than expected, we conclude that cancers rarely occur at the site of lesions observed in the distant past. © 2006 Wiley‐Liss, Inc.
Enhancement of myoblast microencapsulation for gene therapy
Authors: Li Anna Aihua , Shen Feng , Zhang Tao , Cirone Pasquale , Potter Murray , Chang Patricia L 
Published: February 2006

AbstractOne method of nonviral‐based gene therapy is to implant microencapsulated nonautologous cells genetically engineered to secrete the desired gene products. Encapsulating the cells within a biocompatible permselective hydrogel, such as alginate‐poly‐L‐lysine‐alginate (APA), protects the foreign cells from the host immune system while allowing diffusion of nutrients and the therapeutic gene products. An important consideration is which kind of cells is the best candidate for long‐term implantation. Our previous work has shown that proliferation and differentiation of encapsulated C2C12 myoblasts in vitro are significantly improved by inclusion of basic fibroblast growth factor (bFGF), insulin growth factor II (IGF‐II), and collagen within the microcapsules (“enhanced” capsules). However, the effects of such inclusions on the functional status of the microcapsules in vivo are unknown. Here we found that comparing the standard with the enhanced APA microcapsules; there was no difference in the rates of diffusion of recombinant products of different sizes, that is, human factor IX (FIX, 65 kDa), murine IgG (150 kDa), and a lysosomal enzyme, β‐glucuronidase (300 kDa), thus providing a key requirement of such an immunoprotective device. Furthermore, the creatine phosphokinase activity and myosin heavy chain staining (markers for differentiation of the myoblasts) and the cell number per capsule in the enhanced microcapsules indicated a higher degree of differentiation and proliferation when compared to the standard microcapsules, thus demonstrating an improved microenvironment for the encapsulated cells. Efficacy was tested in a melanoma cancer tumor model by treating tumor induced by B16‐F0/neu tumor cells in mice with myoblasts secreting angiostatin from either the standard or enhanced APA microcapsules. Mice treated with enhanced APA‐microcapsules had an 80% reduction in tumor volume at day 21 compared to a 70% reduction in those treated with standard APA‐microcapsules. In conclusion, enhancement of APA microcapsules with growth factors and collagen did not adversely affect their permeability property and therapeutic efficacy. However, the enhanced differentiation and viability of the encapsulated myoblasts in vivo should be advantageous for long‐term delivery with this method of gene therapy. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Composite coating of bonelike apatite particles and collagen fibers on poly L‐lactic acid formed through an accelerated biomimetic coprecipitation process
Authors: Chen Yun , Mak Arthur F. T. , Wang Min , Li Jiashen 
Published: February 2006

AbstractCollagen and apatite were coprecipitated as a composite coating on poly L‐lactic acid (PLLA) in an accelerated biomimetic process. The incubation solution contained collagen (1 g/L) and simulated body fluid with 5 times inorganic ionic concentrations as human blood plasma. The coating formed on PLLA films and scaffolds after a 24‐h incubation was characterized by using energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM). It was shown that the coating contained carbonated bonelike apatite and collagen, which was similar in composition to natural bone. SEM showed a complex composite coating of submicron bonelike apatite particulates combined with collagen fibrils. It is expected that such biocomposite coating may better facilitate cell interaction and osteoconductivity. This work provided an efficient process to obtain bonelike apatite/collagen composite coating, which is potentially useful in bone tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
PLA stereocopolymers as sources of bioresorbable stents: Preliminary investigation in rabbit
Authors: Lafont Antoine , Li Suming , Garreau Henri , Cornhill Frederic , Vert Michel 
Published: February 2006

AbstractThe aim of the present work was to evaluate whether the degradation of PLA‐based bioresorbable stents can be modulated via the configuration of repeating units as it is the case in other applications like osteosynthesis. The first obstacle was finding a stent design that could allow implantation in the aorta of a rabbit taken as a model of a human coronary artery. In the absence of guidelines other than those tentatively proposed in patents, several simple designs were considered that allowed us to evaluate the fate of the stents made of poly(lactic acid) stereocopolymers with L/(L + D) ratio of 0.92 (PLA92) and 0.50 (PLA50) up to 6 months post in vivo implantation. Our findings show the feasibility of bioresorbable stenting using PLA stereocopolymers and that PLA50 degraded faster than PLA92. Therefore, using stereocopolymers appears as a means to vary the degradation rate and adapt it to the artery remodelling process that is very much dependent on the release of the stenting stress protection. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
A mechanism on why slower polymerization of a dental composite produces lower contraction stress
Authors: Feng L. , Suh B. I. 
Published: February 2006

AbstractIt has been well documented that the rate of polymerization of a dental composite often affects its polymerization contraction stress. In most cases, a slower cure produces a lower stress. To investigate the mechanism behind this, we prepared an unfilled dimethacrylate resin sample and photocured it using two light irradiances, both with the same total irradiation energy. We measured the polymerization‐induced shrinkage from the unbonded surface of a class I restoration, contraction stress, extent of polymerization, and flexural modulus. The resin specimens cured under the two irradiances achieved the same extent of polymerization and developed an identical amount of shrinkage from the unbonded surface. But those cured under the lower irradiance possessed a lower contraction stress and a lower flexural modulus than those cured under the higher irradiance. We demonstrated that the stress level did not respond to the extent of viscous flow of the curing resin because the slower polymerization did not produce more shrinkage from the unbonded surface. Instead, the lower stress is likely due to a lower modulus of the cured resin. To explain why the cured resin with an identical extent of polymerization can have different moduli, we proposed that slower polymerization produces a higher level of structural inhomogeneity, which reduces the rigidity of the cured resin. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Oxidation and oxidation potential in contemporary packaging for polyethylene total joint replacement components
Authors: Costa Luigi , Bracco Pierangiola , Brach del Prever Elena Maria , Kurtz Steven M. , Gallinaro Paolo 
Published: February 2006

AbstractThe packaging and chemical stability of both conventional and highly crosslinked polyethylene (PE) components available for clinical use in Italy were analyzed. A total of 100 sterilized PE components were entered by 18 orthopedic manufacturers into the study. Six of the manufacturers were Italian and the remaining were based in Europe or America. Hydroperoxide, oxidation, and trans‐vinylene levels within the PE components were characterized using Fourier‐transform infrared spectroscopy (FTIR). None of the 31 gas‐sterilized components had detectable free radicals, hydroperoxide content, or oxidation. Among radiation‐sterilized inserts, the highest oxidation and hydroperoxide levels were associated with gas‐permeable and polymer‐barrier packaging. To the authors' knowledge, this is the first study that relates elevated oxidation and hydroperoxide content in γ‐sterilized PE components to certain types of contemporary, polymeric barrier packaging. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Cytotoxic effects of dental desensitizers on human gingival fibroblasts
Authors: Sengun A. , Buyukbas S. , Hakki S. S. 
Published: February 2006

AbstractThe purpose of this study was to evaluate the effects of three different desensitizers on the cell viability and morphology of human gingival fibroblasts (HGF). Human gingival tissues were obtained from individuals who have clinically, healthy periodontium. HGF were grown at 37°C in humidified atmosphere of 5% CO2 in Dulbecco's modified eagle's medium, supplemented with glutamine, penicillin, streptomycin, and 10% fetal bovine serum. The cells were treated with different concentrations (0.1, 0.3, and 0.5 μL/mL) of desensitizers (Gluma Desensitizer, Seal&Protect, and MicroPrime). After 24‐ and 48‐h exposure to the desensitizer solutions, the viable cells were examined using a hemocytometer. To monitor HGF viability, 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl tetrazolium bromide (MTT) colorimetric assay was used and cell morphology was also observed at 48 h. Following exposure to concentrations of 0.1 μL/mL of test materials for 24 h, cell survival rates for Gluma Desensitizer (106%) and Micro Prime (62%) were not significantly different from the control, while it was significant for Seal&Protect (50%). Growing cells were significantly inhibited by all tested materials for 48 h (p < 0.05) in survival rates of 51, 47, and 31%, respectively. On the basis of the MTT assay, the cytotoxic effect of MicroPrime was more prominent, especially at high concentrations, than does Gluma Desensitizer and Seal&Protect. After exposure to Seal&Protect and MicroPrime, HGF became retracted, rounded in appearance and had loss of normal organization, leading to enlargement of intercellular space when compared with Gluma Desensitizer. As a conclusion, taking the limitations of an in vitro experiment into consideration, the cytotoxic effects were varied, depending on the chemical composition and exposure periods of the tested desensitizers. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
The nature of platinum in silicones for biomedical and healthcare use
Authors: Lambert James M. 
Published: February 2006

AbstractSilicone is an important biomaterial in many different biomedical and healthcare applications. Network formation in one type of silicone relies upon a chemical crosslinking reaction that typically employs a platinum catalyst. As a consequence, low concentrations of platinum may remain in certain medical devices designed for human use. The characteristics of platinum in silicone before, during, and after the crosslinking reaction have been well described in the literature. This review summarizes the relevant literature on the organometallic and analytical chemistry of platinum in silicone and thus provides a foundation for understanding the effects this platinum may have, if any, in the various biomedical and healthcare applications where it may be present. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Synthesis and performance of amphiphilic copolymers for blood cell separation
Authors: Natori Shizue Hayashi , Gomei Yumiko , Higuchi Akon 
Published: February 2006

AbstractThree types of amphiphilic copolymers using n‐butylmethacrylate (BMA) as a hydrophobic monomer, and each of N,N′‐dimethylacrylamide (DMA), N‐acryloylmorpholine (AMO), and N‐vinylpyrrolidone (VP) as hydrophilic comonomers were synthesized for coating filters used to remove leukocytes. The influence of the amphiphilic property of the resulting filters, which were composed of nonwoven fabrics coated with the above copolymers, on leukocyte removal and platelet permeation through the filters from whole blood was investigated. The platelet permeation ratio through hydrophobic noncoated filters was only 0.2%, because platelets in whole blood adhered easily to the hydrophobic filter material. However, filters coated with poly(AMO‐co‐BMA) of high AMO content showed a much higher platelet permeation ratio (nearly 90%). Further, the filters coated with poly(DMA‐co‐BMA) also showed high permeation ratios of platelets (more than 78%) over a broad range of DMA content in the copolymer. On the other hand, the coated filters showed slightly a higher permeation ratio of leukocytes than did the noncoated filters, resulting from the increase in hydrophilicity of the surface of the filters. Moreover, the coating of the amphiphilic copolymers on the surface of the nonwoven fabrics may have affected the pore size of the filters, affecting the permeation ratio of leukocytes more strongly than that of platelets. The coated filters effectively improved platelet permeation through the filters, with a slight increase in the permeation ratio of leukocytes. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Morphological assessment of the behavior of three‐dimensional anionic collagen matrices in bone regeneration in rats
Authors: Miguel Fúlvio B. , Cardoso Ana Karina M. V. , Barbosa Aryon A. , Marcantonio Elcio , Goissis Gilberto , Rosa Fabiana P. 
Published: February 2006

AbstractThe osteogenic behavior of three‐dimensional collagenic and anionic matrices (M3DGA) implanted in critical bone defects of 8 mm diameter was morphologically assessed. The defects were performed in the calvaria of 48 adult male (Wistar) rats, and observed at days 15, 30, and 60. The animals were distributed in four groups of equal number: GA1 (M3DGA with 60 min of cross‐linking in glutaraldehyde [GA]); GA2 (M3DGA with 30 min of cross‐linking in GA); GA3 (M3DGA with 15 min of cross‐linking in GA); and G4 (control group, without any implanted biomaterial). The M3DGAs were biocompatible, with mild and regressive chronic granulomatous inflammation, associated with the degradation of their fibers. Furthermore, tissue neovascularization and neomineralization was noted, with statistically significant differences in these amounts among the groups (GA1, GA2, and GA3) and G4. In G4 neoformation was limited to the edges of the defect as well as interstitial fibrosis. Under the experimental conditions and for the parameters analyzed, the M3DGAs had osteogenic behavior, which was more evident in M3DGA 15 min. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Effect of pH and temperature on orthodontic NiTi wires immersed in acidic fluoride solution
Authors: Ahn Hyung‐Soo , Kim Myong‐Jin , Seol Hyo‐Joung , Lee Jung‐Hyun , Kim Hyung‐Il , Kwon Yong Hoon 
Published: February 2006

AbstractOrthodontic arch wires can confront diverse pH and temperature conditions in the oral cavity after replacement. The current study evaluated the effect of pH and temperature on orthodontic NiTi arch wires after immersion in an acidic fluoride solution. The acetic acid added for the adjustment of pH forms hydrofluoric acid (HF). More HF was formed in a solution of lower pH with higher temperature than that of the higher pH with lower temperature. Within the same pH value, the temperature of the solution affected the concentration of HF. Each as‐received wire exhibited quite different microhardness values. The reduction of microhardness, 1.2–5.7%, occurred after immersion. Within the same product, however, the pH and temperature had minor influence on the reduction. The volumetric weight change, concentration of the released elements, and surface morphology were influenced by pH and temperature. At pH 3.5 of 60°C solution, the greatest weight loss, release of elements, and corrosion of surface occurred from the wires. At pH 6, on the other hand, no such loss or release occurred regardless of temperature. At 5°C solution, the surface exhibited minor corrosion regardless of pH value. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
The effect of fiber insertion on fracture resistance of endodontically treated molars with MOD cavity and reattached fractured lingual cusps
Authors: Belli Sema , Cobankara Funda Kont , Eraslan Oğuz , Eskitascioglu Gürcan , Karbhari Vistasp 
Published: February 2006

AbstractIn this study, the effect of flowable composite reinforced with a leno wave ultra high modulus (LWUHM) polyethylene fiber (Ribbond) on fracture resistance of endodontically treated molars with MOD cavity and lingual cuspal fracture was evaluated. Sixty sound extracted human mandibular molars were randomly assigned to six groups (n = 10). Group 1 served as control. Teeth in groups 2–6 received root canal treatment and a MOD cavity preparation. Teeth in group 2 were kept unrestored. Lingual walls of specimens in groups 3–6 were fractured at the CEJ and reattached (C&B Super‐Bond). Group 3 was kept unrestored, and group 4 was restored with a composite resin (CR) (AP‐X). In group 5, a flowable resin (FR, Protect Liner F) and in group 6, a Ribbond in combination with FR were inserted inside the cavity before CR restoration. After finishing and polishing, the specimens were subjected to compressive loading perpendicular to the occlusal surface at a crosshead speed of 1 mm/min. The mean load necessary to fracture were recorded in Newton and the results were statistically analyzed. MOD cavity preparation reduced fracture resistance of endodontically treated teeth (p < 0.05). Fracture resistance of rebonded fractured specimens was found to be similar to that of the nonfractured samples (p > 0.05). Use of LWUHM polyethylene fiber Ribbond increased fracture strength of endodontically treated molar teeth with MOD cavity preparation and cuspal fracture (p < 0.05). As a result, it was concluded that the insertion of Ribbond inside the cavity has a positive effect on fracture strength of endodontically treated molar teeth with MOD cavity preparation and cuspal fracture. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Transverse fracture of brittle bilayers: Relevance to failure of all‐ceramic dental crowns
Authors: Kim Jae‐Won , Bhowmick Sanjit , Hermann Ilja , Lawn Brian R. 
Published: February 2006

AbstractThis study examines the behavior of cracks approaching interfaces in all‐ceramic dental crown‐like bilayers. Flat specimens are fabricated by fusing porcelain veneers onto yttria‐tetragonal‐zirconia‐polycrystal (Y‐TZP) and alumina core ceramic plates, with veneer/core matching to minimize residual thermal expansion mismatch stresses. Vickers indentations are placed on either side of the interfaces, at systematically decreasing distances, so that the lead corner cracks approach and intersect the interfaces in a normal orientation. Cracks originating in the porcelain arrest at the boundaries and, after further diminution in indentation distance, deflect along the interface without penetration into the tough core ceramic. Cracks initiating in the core ceramic pass unimpeded into the weaker porcelain without deflection, and with abrupt increase in crack size. These latter cracks, because of their lack of containment within the core layer, are regarded as especially dangerous. Implications concerning the design of optimal dental crowns in relation to materials optimization are considered. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
The internalized CdSe/ZnS quantum dots impair the chondrogenesis of bone marrow mesenchymal stem cells
Authors: Hsieh Shu‐Chen , Wang Fung‐Fang , Hung Shih‐Chieh , Chen Yu‐Ju , Wang Yng‐Jiin 
Published: February 2006

AbstractMesenchymal stem cells (MSCs) are capable of differentiating into multiple cell lineages and are useful for therapeutic applications. Labeling the MSCs with fluorescent probes is beneficial in tracing the fate of MSCs after implantation. We have introduced the CdSe/ZnS quantum dots (QDs) into the human bone marrow MSCs and examined the effects of QDs on the proliferation and chondrogenesis of the cells. The internalized QDs were found localized in perinuclear regions and remained there after a number of cell passages. The presence of QDs did not affect the proliferation of cells or the size of chondrospheres formed, when subjected to chondrogenesis induction. However, the expression of mRNA and protein of type II collagen and aggrecan in the chondrospheres was significantly inhibited in cells labeled with QDs, suggesting impaired chondrogenesis. Our results that the presence of QDs interferes with the chondrogenic differentiation of MSCs raise concerns in using the QDs as fluorescence tracers for stem cells. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Leptin effect on RANKL and OPG expression in MC3T3‐E1 osteoblasts
Authors: Lamghari M. , Tavares L. , Camboa N. , Barbosa M.A. 
Published: February 2006

AbstractRecent studies have suggested that leptin hormone may play a pivotal role on bone remodeling through a direct effect by modulating positively the OPG/RANKL balance. Here, we investigate the effect of leptin hormone on RANKL and OPG expression in MC3T3‐E1 osteoblasts using RT‐PCR and ELISA measurements. We have at first identified the expression of Ob‐Rb and Ob‐Ra leptin receptor isoforms in MC3T3‐E1 and observed that these cells respond to mrleptin treatments. We then investigated the effect of mrleptin on RANKL and OPG expression. We show that mrleptin dose‐dependently regulated the expression of RANKL mRNA with complete inhibition observed at concentrations higher than 12 ng/ml. This effect was confirmed with sRANKL protein measurements. However, the exposure of MC3T3‐E1 to mrleptin had no effect on OPG mRNA. Taken together, these results suggest that leptin modulates positively OPG/RANKL balance by inhibiting the expression of RANKL gene. J. Cell. Biochem. 98: 1123–1129, 2006. © 2006 Wiley‐Liss, Inc.