bluuebunny/crossref_metadata_2025_split huggingface dataset:
Processing, characterization, andin vitro/in vivoevaluations of powder metallurgy processed Ti‐13Nb‐13Zr alloys
Authors: Bottino Marco C. , Coelho Paulo G. , Henriques Vinicius A. R. , Higa Olga Z. , Bressiani Ana H. A. , Bressiani José C. 
Published: March 2008

AbstractThis article presents details of processing, characterization andin vitroas well asin vivoevaluations of powder metallurgy processed Ti‐13Nb‐13Zr samples with different levels of porosity. Sintered samples were characterized for density, crystalline phases (XRD), and microstructure (SEM and EDX). Samples sintered at 1000°C showed the highest porosity level (∼30%), featuring open and interconnected pores ranging from 50 to 100 μm in diameter but incomplete densification. In contrast, samples sintered at 1300 and 1500°C demonstrated high densification with 10% porosity level distributed in a homogeneous microstructure. The different sintering conditions used in this study demonstrated a coherent trend that is increase in temperature lead to higher sample densification, even though densification represents a drawback for bone ingrowth. Cytotoxicity tests did not reveal any toxic effects of the starting and processed materials on surviving cell percentage. After an 8‐week healing period in rabbit tibias, the implants were retrieved, processed for nondecalcified histological evaluation, and then assessed by backscattered electron images (BSEI‐SEM) and EDX. Bone growth into the microstructure was observed only in samples sintered at 1000°C. Overall, a close relation between newly formed bone and all processed samples was observed. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Retention and biodistribution of microspheres injected into ischemic myocardium
Authors: Anderl Jeff N. , Robey Thomas E. , Stayton Patrick S. , Murry Charles E. 
Published: March 2008

AbstractIntramyocardial injection of therapeutic agents may enhance heart repair after infarction. Incomplete retention of intramyocardial injections has been reported, but modes of loss are undefined. We determined the fate of neutron‐activated microspheres injected into acutely ischemic rat myocardium using saline, Pluronic F127, or Matrigel as vehicle. Twenty minutes after injection in saline, 63% ± 12% of 10‐μm microspheres was retained in the heart. Similar retention was observed after 6 days. Injection site leakage accounted for 14% ± 5% of the microspheres, whereas exit via coronary veins resulted in 11.2% ± 9.5% collecting in the lungs. Microspheres distribution to other organs was minimal. Retention of 40‐μm microspheres was similar to that observed with the 10‐μm microspheres. Pluronic F127 and Matrigel reduced immediate leakage to 4% ± 1% and 2% ± 1%, respectively. Surprisingly, microsphere retention in the heart was not improved at 20 min using either gelling vehicle, suggesting that leakage occurs over a prolonged period. Thus, most injected particles are retained in the ischemic rat heart following direct injection, but significant fractions are lost from the injection site and through coronary veins. Gelling agents reduced short‐term leakage, but failed to enhance longer‐term retention. Hydrogels with stiffer mechanical properties might enhance retention and reduce variability. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Immunohistochemical identification of MMP‐2 and MMP‐9 in human dentin: Correlative FEI‐SEM/TEM analysis
Authors: Mazzoni Annalisa , Pashley David H. , Tay Franklin R. , Gobbi Pietro , Orsini Giovanna , Ruggeri Alessandra , Carrilho Marcela , Tjäderhane Leo , Di Lenarda Roberto , Breschi Lorenzo 
Published: March 2008

AbstractMatrix metalloproteinases (MMPs) are a family of peptidases trapped within mineralized dentin matrix and involved with degradation of the extracellular matrix components in hybrid layers and caries. Despite their identification through indirect evidences and biochemical assays, MMP‐2 and ‐9 have not been localized within the human dentin extracellular organic matrix. Thus, this study aimed to assess the localization and distribution of MMP‐2 and ‐9 in human dentin organic matrix by employing a correlative field emission in‐lens‐scanning electron microscopy (FEI‐SEM) and transmission electron microscopy (TEM) immunohistochemical approach. Dentin specimens were submitted either to a preembedding or to a postembedding immunolabeling technique using primary monoclonal antibodies anti‐MMP‐2 and anti‐MMP‐9 and exposed to a secondary antibody conjugated with gold nanoparticles. MMP‐2 and ‐9 labelings were identified in the demineralized dentin matrix as highly electron‐dense gold particles dispersed on the collagen fibrils. Correlative FEI‐SEM/TEM observations confirmed that MMP‐2 and MMP‐9 are endogenous components of the human dentin organic matrix and revealed the three‐dimensional relationship between these proteinases and the collagen fibrils, showing that both antibodies yielded a similar labeling pattern. In conclusion, the results of the study contribute to reveal distinct distribution pattern of gelatinases and support the hypothesis that these enzymes are intrinsic constituents of the dentin organic matrix after decalcification. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Effects of fabrication parameters on viscoelastic shear modulus of 2,3‐dialdehydecellulose membranes—Potential scaffolds for vocal fold lamina propria tissue engineering
Authors: RoyChowdhury Priyanka , Klemuk Sarah , Titze Ingo , Kumar Vijay 
Published: March 2008

AbstractPorous 2,3‐dialdehydecellulose (2,3‐DAC) membranes were investigated for use as a synthetic scaffold for engineering vocal fold‐like tissues. Two criteria of this application are (i) the viscoelastic shear properties of the scaffold should be controllable in the range of vocal fold tissues and (ii) scaffolds should remain biomechanically stable to withstand vibrational stresses in a bioreactor. Porous 2,3‐DAC membranes were fabricated from methylolcellulose by water‐induced cellulose regeneration, with or without sodium chloride leaching, followed by periodate oxidation. They were freeze‐dried and ethylene oxide‐sterilized. Different degrees of oxidation were obtained on reacting with sodium metaperiodate for different time points. Rheological studies were performed to investigate the effect of freeze‐drying, porosity, degree of oxidation, sterilization, and incubation time on elastic and viscous shear moduli, G′ and G″, respectively, for frequencies 0.01–10 Hz. Freeze drying increased G′ and G″, while increased porosity and degree of oxidation reduced G′ and G″. Sterilization had no effect on viscoelasticity. When incubated in Dulbecco's minimum essential medium at 37°C, membranes with 6–7% and 19–20% oxidation disintegrated after 7 and 3 days, respectively, while membranes with 3–4% oxidation showed little viscoelastic change over a period of 42 days. The upper frequency limit of rheologic measurement was a limitation of the study and should be addressed in future investigations. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Effects of gold coating on experimental implant fixation
Authors: Zainali Kasra , Danscher Gorm , Jakobsen Thomas , Jakobsen Stig S. , Baas Jørgen , Møller Per , Bechtold Joan E. , Soballe Kjeld 
Published: March 2008

AbstractInsertions of orthopedic implants are traumatic procedures that trigger an inflammatory response. Macrophages have been shown to liberate gold ions from metallic gold. Gold ions are known to act in an antiinflammatory manner by inhibiting cellular NF‐κB–DNA binding and suppressing I‐κ B‐kinase activation. The present study investigated whether gilding implant surfaces augmented early implant osseointegration and implant fixation by its modulatory effect on the local inflammatory response. Ion release was traced by autometallographic silver enhancement. Gold‐coated cylindrical porous coated Ti6Al4V implants were inserted press‐fit in the proximal part of tibiae in nine canines and control implants without gold inserted contralateral. Observation time was 4 weeks. Biomechanical push‐out tests showed that implants with gold coating had ∼50% decrease in mechanical strength and stiffness. Histomorphometrical analyses showed gold‐coated implants had a decrease in overall total bone‐to‐implant contact of 35%. Autometallographic analysis revealed few cells loaded with gold close to the gilded implant surface. The findings demonstrate that gilding of implants negatively affects mechanical strength and osseointegration because of a significant effect of the released gold ions on the local inflammatory process around the implant. The possibility that a partial metallic gold coating could prolong the period of satisfactory mechanical strength, however, cannot be excluded. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
The bone‐derived collagen containing mineralized matrix for the loading of collagen‐binding bone morphogenetic protein‐2
Authors: Zhao Yannan , Chen Bing , Lin Hang , Sun Wenjie , Zhao Wenxue , Zhang Jing , Dai Jianwu 
Published: March 2008

AbstractBone tissue‐derived biomaterials have often been applied for bone repair because of their similarity to human bone in structure and composition. When combined with growth factors, they could accelerate bone formation. Here, we explore a collagen containing mineralized bone‐derived matrix (CCMBM) from bovine bone tissues, which not only maintains proper mechanical strength but also binds to the collagen‐binding recombinant human collagen‐binding bone morphogenetic protein‐2 (CBD‐BMP2). By analyzing its morphology and composition, we found that CCMBM was porous and mainly composed of calcium compounds. CCMBM could provide mechanical support for bone injury repair. It also showed good biocompatibility and proper degradation rate that would be helpful for bone regeneration. In addition, the intentionally preserved collagen allowed the specific binding of CBD‐BMP2 to CCMBM, and resulted in significantly increased osteogenesis in vivo. The results indicated that the combination of CCMBM with collagen‐binding BMP2 could be emerged into an effective medical device for bone repair. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Antimicrobial activity and local release characteristics of chlorhexidine diacetate loaded within the dental copolymer matrix, ethylene vinyl acetate
Authors: Arnold Roland R. , Wei Hong Hong , Simmons Eric , Tallury Padmavathy , Barrow David A. , Kalachandra Sid 
Published: March 2008

AbstractIn vitro results are presented for a novel oral drug‐delivery system ultimately intended for treatment of oral infections in immunocompromised patients. Test samples of ethylene vinyl acetate copolymer (EVA) containing chlorhexidine diacetate (CDA) showed desirable antimicrobial properties and steady, slow release into aqueous and other media after an initial burst of drug release in the first day of liquid exposure. By washing away this initial burst, the proposed mouthguard device should be capable of sustained delivery of locally effective CDA concentrations far below systemically toxic levels. A prolonged room temperature shelf‐life of at least 1 year, and effectivity against a wide range of oral bacteria and Candida species was demonstrated. Drug loaded films showed a top‐to‐bottom asymmetry in drug release, but good lateral homogeneity, and a linear relationship between initial CDA loading concentration (from 0.63 to 10 wt %) and days 3–14 release rates in a static aqueous environment. The EVA matrix containing CDA appears to possess many suitable properties for localized oral delivery of sustained antimicrobial activity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Effect of porosity and pore size on microstructures and mechanical properties of poly‐ε‐caprolactone‐ hydroxyapatite composites
Authors: Yu Haiying , Matthew Howard W. , Wooley Paul H. , Yang Shang‐You 
Published: March 2008

AbstractThe influence of variant pore‐size and porosity on the microstructure and the mechanical properties of poly‐ε‐caprolactone (PCL) and hydroxyapatite (HA) composite were examined for an optimal scaffold in bone tissue engineering. Three various amounts of sodium chloride (NaCl, as porogens) with two distinct particle size ranges (212–355 μm and 355–600 μm) were blended into PCL and HA mixture, followed by a leaching technique to generate PCL‐HA scaffolds with various pores and porosity. The porosities of the scaffolds were correlated with the porogen size and concentration. The morphological properties of the resulting scaffolds were assessed by micro‐computerized tomography (μCT), scanning electron microscopy (SEM), and energy dispersive X‐ray analysis (EDX). Extensive PCL‐HA pore interconnections with thinner pore walls were present in scaffolds with higher concentration (4:1 w/w) and larger particulate of porogen used in the fabrication process. Embedding of HA particles in the scaffold resulted in rough surfaces on the composites. Instron actuator testing indicated that the tensile strengths and Young's moduli of scaffolds were influenced by both the porosities and pore sizes of the scaffold. It was apparent that increasing the concentration of porogen compromised the mechanical properties; and a larger porogen particle size led to increased tensile strength but a reduction in Young's modulus. Overall, the data indicated that modification of the concentration and particle size of porogen altered the porous features and mechanical strength of HA‐PCL scaffolds. This provided means to manipulate the properties of biocompatible cell‐supporting scaffolds for use as bone graft substitutes. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Evaluation of a flexible collagen surgical patch for reinforcement of a fascial defect: Experimental study in a sheep model
Authors: Sullivan Eileen K. , Kamstock Debra A. , Turner A. Simon , Goldman Scott M. , Kronengold Russell T. 
Published: March 2008

AbstractThere is a need for a surgical mesh that can be used in general surgical procedures for reinforcement or repair of soft tissue. Collagen based surgical meshes may possess the appropriate qualities. In this study, the potential of a collagen product BioBlanket™ Surgical Mesh to facilitate soft tissue repair in an ovine fascial defect model in vivo was evaluated. BioBlanket Surgical Mesh facilitated soft tissue repair in an ovine fascial defect model in vivo. Superficial fascial surgical sites were evaluated grossly, histologically, and mechanically at 6 and 12 week time points. BioBlanket Surgical Mesh and the predicate device Restore® Orthobiologic Implant both performed favorably when implanted in superficial fascial defects compared with the negative control empty defect. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
A Doppler waveform index to characterize hepatic vein velocity pattern and evaluate hepatic fibrosis
Authors: Pedersen Jan Fog , Madsen Lone Galmstrup , Larsen Vibeke Andrée , Hamberg Ole , Horn Thomas , Federspiel Birgitte , Bytzer Peter 
Published: March 2008

AbstractPurpose.To describe a Doppler waveform index representing the hepatic vein flow velocity pattern and to examine its relationship to the degree of hepatic fibrosis.Methods.Doppler waveforms were obtained in 66 patients scheduled for percutaneous liver needle biopsy and categorized as normal (with a retrograde flow phase) or abnormal (without retrograde flow). Waveforms were also characterized using a hepatic vein waveform index (HVWI): (maximum − minimum velocity)/(maximum velocity). Biopsy specimens were graded for fibrosis.Results.There was a highly significant decrease in HVWI with increasing fibrosis score in the biopsy (p < 0.001, Jonckheere trend test). The biopsy showed cirrhosis in 14 of 29 patients (48%) with absent retrograde flow and 5 of 37 patients (14%) with a normal flow pattern. Using HVWI as the criterion, cirrhosis was present in 13 of 21 (62%) patients with HVWI < 0.75, in 6 of 31 (19%) patients with 0.75 < HVWI < 1.50, and in none of 14 (0%) patients with HVWI > 1.50.Conclusions.HVWI is inversely correlated to the degree of liver fibrosis and may be more efficient than the presence or absence of retrograde flow in diagnosing and grading hepatic fibrosis. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2008.
Alleviating the consequences of marginalisation? EU aid policy towards the Caribbean ACPs
Authors: Clegg Peter L. 
Published: March 2008

AbstractThe article reviews the EU's development policy in relation to the Caribbean members of the African, Caribbean and Pacific (ACP) group. It considers the particular challenges faced by these small economies before assessing their trade and aid relationship with the EU. The article evaluates both the regional assistance programme and the particular experiences of Guyana and Jamaica. Both countries are singled out because of the breadth and depth of their aid relationship with the EU. Finally, the article provides an analysis of EU aid policy within the context of EU–Caribbean relations more generally. Copyright © 2008 John Wiley & Sons, Ltd.
Nonmotor symptoms in Parkinson's disease: Investigating early‐phase onset of behavioral dysfunction in the 6‐hydroxydopamine‐lesioned rat model
Authors: Branchi Igor , D'Andrea Ivana , Armida Monica , Cassano Tommaso , Pèzzola Antonella , Potenza Rosa Luisa , Morgese Maria Grazia , Popoli Patrizia , Alleva Enrico 
Published: March 2008

AbstractTo investigate the psychiatric symptoms accompanying the early phases of Parkinson's disease (PD), we injected adult rats with 10.5 μg 6‐hydroxydopamine (6‐OHDA) bilaterally into the dorsal striatum. The resulting neurodegeneration led, 12 weeks after injection, to a mild (36%) reduction of striatal dopamine. We tested the behavioral response of sham and 6‐OHDA‐lesioned animals at different time points after injection to evaluate the onset and progression of behavioral abnormalities. The results showed that such a mild reduction of dopamine levels was associated with a decrease in anxiety‐like behavior, an increase in “depression”‐like behavior, and a marked change in social behavior. Learning and memory abilities were not affected. Overall, the PD rat model used here displays behavioral alterations having face validity with psychiatric symptoms of the pathology and thus appears to be a valuable tool for investigating the neural bases of the early phases of PD. © 2008 Wiley‐Liss, Inc.
Role of protein kinase Cδ in paraquat‐induced glial cell death
Authors: Kim Sangseop , Hwang Jaegyu , Lee Won‐Ha , Hwang Dae Youn , Suk Kyoungho 
Published: March 2008

AbstractParaquat (1,1′‐dimethyl‐4,4′‐bipyridinium) is structurally similar to the neurotoxin 1‐methyl‐4‐phenyl‐4‐phenylpyridium ion (MPP+), the active metabolite of the parkinsonism‐inducing agent 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP), which can induce the parkinsonism property in rodents, nonhuman primates, and human. In contrast to the neurotoxic effects of paraquat, little is known about its effects on glial cells. Here, we examined the mechanisms of paraquat toxicity in glial cells in culture. Paraquat treatment also reduced the viability of C6 glial cells in primary astrocyte cultures, and cell death was mostly apoptotic in nature. PKCδ played a central role in the paraquat‐induced glial cell death: (1) the PKCδ‐specific inhibitor rottlerin blocked paraquat‐induced glial cell death; (2) paraquat induced tyrosine and threonine phosphorylation of PKCδ; and (3) transfection of the dominant‐negative mutant of PKCδ attenuated paraquat toxicity. PKCδ was also involved in the generation of reactive oxygen species (ROS), which mediated the paraquat toxicity. The nicotinamide adenine dinucleotide phosphate (reduced form) oxidase (NADPH oxidase) inhibitor diphenyleneiodonium blocked the paraquat‐induced ROS production and subsequent cell death, indicating the involvement of NADPH oxidase in the cytotoxic action of paraquat in glia. PKCδ was also important in glial cell death induced by MPP+ but not in that induced by rotenone. Last, Rac1 appeared to antagonize paraquat toxicity in glia. These results indicate a gliotoxic effect of paraquat and an opposing role of PKCδ and Rac1 in paraquat‐induced glial cell death. © 2008 Wiley‐Liss, Inc.
Immune or inflammatory response by the host brain suppresses neuronal differentiation of transplanted ES cell–derived neural precursor cells
Authors: Ideguchi Makoto , Shinoyama Mizuya , Gomi Masanori , Hayashi Hideki , Hashimoto Nobuo , Takahashi Jun 
Published: March 2008

AbstractEmbryonic stem (ES) cells are a promising donor source for transplantation therapy, but several problems must be solved before they can be clinically useful. One of these is the host immune reaction to allogeneic grafts. In this article, we examine the effect of the host immune reaction on survival and differentiation of grafted ES cell–derived neural precursor cells (NPCs). We induced NPCs from mouse ES cells by stromal cell–derived inducing activity and then transplanted them into mouse brains with or without administering the immunosuppressant cyclosporine A (CsA). Two and 8 weeks following transplantation, the accumulation of host‐derived microglia/macrophages and lymphocytes was observed around the graft. This effect was reduced by CsA treatment, although no significant difference in graft volume was observed. These data suggest that an immune response occurs in allografts of ES cell–derived NPCs. Intriguingly, however, the ratio of neurons to astrocytes in the graft was higher in immunosuppressed mice. Because inflammatory or immune cells produce various cytokines, we examined the effect of IL‐1β, IL‐6, IFN‐γ, and TNF‐α on the differentiation of NPCs in vitro. Only IL‐6 promoted glial cell fate, and this effect could be reversed by the addition of an IL‐6 neutralizing antibody. These results suggest that allogeneic ES cell–derived NPCs can cause an immune response by the host brain, but it is not strong enough to reject the graft. More important, activated microglia and lymphocytes can suppress neuronal differentiation of grafted NPCs in vivo by producing cytokines such as IL‐6. © 2008 Wiley‐Liss, Inc.
MBNL1 associates with YB‐1 in cytoplasmic stress granules
Authors: Onishi Hayato , Kino Yoshihiro , Morita Tomoko , Futai Eugene , Sasagawa Noboru , Ishiura Shoichi 
Published: March 2008

AbstractThe muscleblind‐like (MBNL) protein family is thought to be involved in the molecular mechanism of myotonic dystrophy (DM). Although it has been shown to have splicing activity, a broader function in cellular RNA metabolism has been implicated. In this study, we attempted to find the binding proteins of MBNL1 in order to elucidate its physiological function. First, we performed a GST pull‐down assay using GST‐MBNL1‐6xHis as bait. Several proteins were identified, including YB‐1, a multifunctional DNA/RNA‐binding protein, and DDX1, a DEAD box RNA helicase. MBNL1 formed an RNP complex with YB‐1 and DDX1 in binding assays. YB‐1 also showed a weak but significant effect on α‐actinin splice site selection. Interestingly, in response to stress, MBNL1 moved to cytoplasmic stress granules, where it colocalized with YB‐1, which was previously reported to be a component of stress granules. We found that DDX1 also colocalized with MBNL1 at stress granules. These results provide new insight into the dynamics of MBNL1 in response to stress, and they suggest a role for MBNL1 in mRNA metabolism in the cytoplasm. © 2008 Wiley‐Liss, Inc.