bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationship of PCDD/F concentrations in duck-egg farmers and consumption of ranched duck eggs in central Taiwan
Authors: Chen Hsiu-Ling , Huang Po-Chin , Lee Ching-Chang 
Published: August 2010

Abstract
The 2004 food market-basket survey in Taiwan found high levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in duck eggs. A subsequent survey in Chang-Hua County, central Taiwan, found nine duck farms for egg production and duck eggs that were highly contaminated by PCDD/Fs in the secondary sampling and analysis during the years 2004 to 2005. Duck-egg farmers eat duck eggs rather than chicken eggs, and the aim of the current study was to evaluate how eating contaminated duck eggs affected serum PCDD/F accumulation and PCDD/F profiles in family members of duck-egg farmers. Forty-two family members of duck-egg farmers and 88 residents living nearby (control group) were recruited. Serum PCDD/F levels were significantly higher in duck-egg farmers than in the control group (28.1 vs 18.6 pg World Health Organization toxic equivalency [TEQ]/g lipid, WHO-TEQ). Significant differences in PCDD/F levels were found for most congeners, especially for 2,3,4,7,8-penta–chlorinated dibenzofurans. Elevated serum PCDD/F levels were positively associated with an increase in monthly duck-egg consumption after adjustments for fish consumption. The current result contradicted results of our previous study, which showed a positive association between fish intake and serum PCDD/F levels. The matter of cultivation in the contaminant area in Chang-Hua County should be considered more seriously. Environ. Toxicol. Chem. 2010;29:2402–2408. © 2010 SETAC
The effect of natural dissolved organic carbon on the acute toxicity of copper to larval freshwater mussels (glochidia)
Authors: Gillis Patricia L. , McGeer James C. , Mackie Gerald L. , Wilkie Michael P. , Ackerman Josef D. 
Published: August 2010

AbstractThe present study examined the effect of dissolved organic carbon (DOC), both added and inherent, on Cu toxicity in glochidia, the larvae of freshwater mussels. Using incremental additions of natural DOC concentrate and reconstituted water, a series of acute copper toxicity tests were conducted. An increase in DOC from 0.7 to 4.4 mg C/L resulted in a fourfold increase (36–150 µg Cu/L) in the 24-h median effective concentration (EC50) and a significant linear relationship (r2 = 0.98, p = 0.0008) between the DOC concentration and the Cu EC50 of Lampsilis siliquoidea glochidia. The ameliorating effect of added DOC on Cu toxicity was confirmed using a second mussel species, the endangered (in Canada) Lampsilis fasciola. The effect of inherent (i.e., not added) DOC on Cu toxicity was also assessed in eight natural waters (DOC 5–15 mg C/L). These experiments revealed a significant relationship between the EC50 and the concentration of inherent DOC (r2 = 0.79, p = 0.0031) with EC50s ranging from 27 to 111 µg Cu/L. These laboratory tests have demonstrated that DOC provides glochidia with significant protection from acute Cu toxicity. The potential risk that Cu poses to mussel populations was assessed by comparing Cu and DOC concentrations from significant mussel habitats in Ontario to the EC50s. Although overall mean Cu concentration in the mussel's habitat was well below the acutely toxic level given the concentration of DOC, episodic Cu releases in low DOC waters may be a concern for the recovery of endangered freshwater mussels. The results are examined in the context of current Cu water quality regulations including the U.S. Environmental Protection Agency's (U.S. EPA) biotic ligand model. Environ. Toxicol. Chem. 2010;29:2519–2528. © 2010 SETAC
Characterization of aneurysmal aortas by biochemical, thermal, and dielectric techniques
Authors: Samouillan Valerie , Dandurand Jany , Lacabanne Colette , Stella Andrea , Gargiulo Mauro , Degani Annamaria , Gandaglia Alessandro , Spina Michel 
Published: August 2010

AbstractAbdominal aortic aneurysms (AAA) are characterized by structural alterations of the aortic wall resulting from the degradation of elastic fibres and an increase of collagen/elastin ratio. In this study we investigated the chain dynamics of AAA tissues by two techniques generally used for the characterization of polymers, Differential scanning calorimetry (DSC) and thermally stimulated currents (TSC), and we correlated the obtained data with biochemical analyses. The thermal denaturation of collagen observed by DSC allowed us to evaluate the thermal stability of the triple helix domain: notable modifications were evidenced between collagen from control tissue and collagen from AAA, particularly concerning the thermal denaturation. The dielectric analysis of pathologic aortic walls by TSC revealed a relevant change of collagen mobility in AAA, with the occurrence of a specific mode of relaxation between −60 and −40°C. Biochemical, thermal, and dielectric results are compatible with increase of new collagen deposition and/or impairment of the collagen phase stability in the extracellular matrix of AAAs. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Pluronic/chitosan hydrogels containing epidermal growth factor with wound‐adhesive and photo‐crosslinkable properties
Authors: Choi Ji Suk , Yoo Hyuk Sang 
Published: August 2010

AbstractWound‐adhesive and thermo‐responsive hydrogels were prepared in an aim to develop a wound‐care device for diabetic ulcers. A mixture of glycidyl methacrylated chitooligosaccharide (COS), di‐acrylated Pluronic, and a recombinant human epidermal growth factor (rhEGF) formed a physical hydrogel. Photo‐irradiation was subsequently applied to chemically crosslink the hydrogel. Release profiles of encapsulated rhEGF from the hydrogel showed that release rates were dependent on degradation rates of hydrogels. Human primary keratinocytes were cultivated with the released fraction from the hydrogel to measure effects of released rhEGF on in vitro differentiation of keratinocytes. Muco‐adhesive property of the hydrogel was investigated in animal skins and significant amounts of quantum dot‐labeled rhEGF were retained at wound sites along with chitosan. The hydrogel was administered to dorsal burn wounds in wound healing impaired animals and photo‐irradiated. COS and rhEGF in the hydrogels significantly enhanced epidermal differentiation during the wound healing process. Thus, the rhEGF‐encapsulated hydrogel was expected to be a potential wound care product by increasing local concentration of rhEGF at wound sites with maintaining keratinocytic differentiation. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Antibacterial coatings of fluoridated hydroxyapatite for percutaneous implants
Authors: Ge Xiang , Leng Yang , Bao Chongyun , Xu Sherry Li , Wang Renke , Ren Fuzeng 
Published: August 2010

AbstractPercutaneous orthopedic and dental implants require not only good adhesion with bone but also the ability to attach and form seals with connective tissues and the skin. To solve the skin‐seal problem of such implants, an electrochemical deposition method was used to modify the surfaces of metallic implants to improve their antibacterial ability and skin seals around them. A dense and uniform fluoridated calcium phosphate coating with a thickness of about 200 nm was deposited on an acid‐etched pure titanium substrate by controlling the current density and reaction duration of the electrochemical process. The as‐deposited amorphous fluoridated calcium phosphate transformed to fluoridated hydroxyapatite (FHA) after heat treatment at 600°C in a water vapor environment for 3 h. Both single crystal diffraction patterns and high‐resolution transmission electron microscope (HRTEM) images confirmed the phase of the fluoridated calcium phosphate after the heat treatment. The antibacterial activities of FHA coatings were tested against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Porphyromonas gingivalis (P. gingivalis) with the film attachment method. The antibacterial activity of FHA coating is much higher than that of pure hydroxyapatite (HA) coating and acid‐etched pure titanium surface. The promising features of FHA coating make it suitable for orthopedic and dental applications. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Paracrine factors from fibroblast aggregates in a fibrin‐matrix carrier enhance keratinocyte viability and migration
Authors: Peura Matti , Siltanen Antti , Saarinen Ira , Soots Anu , Bizik Jozef , Vuola Jyrki , Harjula Ari , Kankuri Esko 
Published: August 2010

AbstractEfficient re‐epithelialization of skin lesions is dependent on paracrine support from connective tissue fibroblasts. In deep skin defects, the supporting growth factor incentive is lacking. Current methods of keratinocyte transplantation with compromised attachment, spread, and cell proliferation warrant improvement and refinement. We describe here how human keratinocytes can be stimulated by matrix‐embedded factors from a novel process of fibroblast activation: nemosis. Interestingly, the unique set of mediators released in this process also plays a key role in normal wound healing. To develop a system for targeted delivery of nemosis‐derived paracrine effectors, herein designated as Finectra, we combined them with fibrin to establish a controlled‐release gel. Keratinocytes seeded to cover this active matrix showed better adherence, outgrowth, and viability than did cells on control matrix. The matrix incorporating Finectra supported viability of both primary keratinocytes and green fluorescent protein (GFP)‐labeled HaCaT cells, as evaluated by MTT assay and persistence of GFP‐fluorescence. The fibrin‐Finectra matrix promoted migration of keratinocytes to cover a larger area on the matrix, suggesting better wound coverage on transplantation. An inhibitor of EGFR/c‐Met receptor tyrosine kinases abolished keratinocyte responses to fibrin‐Finectra matrix. This matrix can thus deliver biologically relevant synergistic stimuli to keratinocytes and hasten re‐epithelialization. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Synthesis of multilayered alginate microcapsules for the sustained release of fibroblast growth factor‐1
Authors: Khanna Omaditya , Moya Monica L. , Opara Emmanuel C. , Brey Eric M. 
Published: August 2010

AbstractAlginate microcapsules coated with a permselective poly‐L‐ornithine (PLO) membrane have been investigated for the encapsulation and transplantation of islets as a treatment for type 1 diabetes. The therapeutic potential of this approach could be improved through local stimulation of microvascular networks to meet mass transport demands of the encapsulated cells. Fibroblast growth factor‐1 (FGF‐1) is a potent angiogenic factor with optimal effect occurring when it is delivered in a sustained manner. In this article, a technique is described for the generation of multilayered alginate microcapsules with an outer alginate layer that can be used for the delivery of FGF‐1. The influence of alginate concentration and composition (high mannuronic acid (M) or guluronic acid (G) content) on outer layer size and stability, protein encapsulation efficiency, and release kinetics was investigated. The technique results in a stable outer layer of alginate with a mean thickness between 113 and 164 μm, increasing with alginate concentration and G‐content. The outer layer was able to encapsulate and release FGF‐1 for up to 30 days, with 1.25% of high G alginate displaying the most sustained release. The released FGF‐1 retained its biologic activity in the presence of heparin, and the addition of the outer layer did not alter the permselectivity of the PLO coat. This technique could be used to generate encapsulation systems that deliver proteins to stimulate local neovascularization around encapsulated islets. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
In vivo evaluation of MMP sensitive high‐molecular weight HA‐based hydrogels for bone tissue engineering
Authors: Kim Jungju , Kim In Sook , Cho Tae Hyung , Kim Ho Chul , Yoon So Jeong , Choi Jaesoon , Park Yongdoo , Sun Kyung , Hwang Soon Jung 
Published: August 2010

AbstractHyaluronic acid (170 kDa)‐based hydrogel was synthesized using acrylated hyaluronic acid (HA) and matrix metalloproteinase (MMP) sensitive HA‐based hydrogels were then prepared by conjugation with two different peptides: cell adhesion peptides containing integrin‐binding domains (Arg‐Gly‐Asp: RGD) and a cross‐linker with MMP degradable peptides to mimic the remodeling characteristics of natural extracellular matrices by cell‐derived MMPs. Mechanical properties of these hydrogels were evaluated with different weight percentages (2.5 and 3.5 wt %) by measuring elastic modulus, viscous modulus, and swelling ratio. Human mesenchymal stem cells (hMSCs) were then cultured in MMP‐sensitive or insensitive HA‐based hydrogels and/or immobilized cell adhesive RGD peptides in vitro. Actin staining and image analysis proved that cells cultured in the MMP‐sensitive hydrogel with RGD peptides showed extensive cell spreading and sprouting. Gene expression analysis showed that bone specific genes such as alkaline phosphatase, osteocalcin, and osteopontin increased in MMP‐sensitive hydrogels as biomolecules such as BMPs and cells were added in the gels. For in vivo calvarial defect regeneration, five different samples (MMP insensitive hydrogel, MMP sensitive hydrogel, MMP sensitive hydrogel with BMP‐2, MMP sensitive hydrogel with hMSC, and MMP sensitive hydrogel with BMP‐2 and hMSC) were prepared. After 4 weeks of implantation, the Masson‐Trichrome staining and micro computed tomography scan results demonstrated that the MMP sensitive hydrogels with BMP‐2 and hMSCs have the highest mature bone formation. The MMP sensitive HA‐based hydrogel could become useful scaffolds in bone tissue engineering with improvements on tissue remodeling rates and regeneration activity. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Rough surface topography enhances the activation of Wnt/β‐catenin signaling in mesenchymal cells
Authors: Galli Carlo , Passeri Giovanni , Ravanetti Francesca , Elezi Erida , Pedrazzoni Mario , Macaluso Guido Maria 
Published: August 2010

AbstractIt is known that the roughness of titanium surfaces affects cell proliferation and differentiation. However, the mechanisms mediating the cellular responses to surface topography are only partially understood. The present study investigated whether Wnt canonical signaling, an important pathway in determining cell fate, is modulated by surface roughness. This study analyzed the behavior of the murine C2C12 mesenchymal cell line on polished or acid‐etched, sand‐blasted (SLA) commercially pure titanium. When we transfected cells with Wnt3a or wild‐type β‐catenin and a reporter construct, we found that stimulation of Wnt canonical signaling was enhanced in cells on SLA surfaces. Moreover, more β‐catenin translocated to the nucleus in cells on SLA surfaces after stimulation with Wnt3a as evidenced by immunofluorescence. However, when cells were transfected with constitutively active S33Y β‐catenin mutant, no difference was observed between the groups. Higher levels of transcripts of Wnt target genes were detected in C2C12 cells cultured on SLA surfaces following transfection with Wnt3a, but the expression of a gene regulating β‐catenin degradation, Axin 2, was reduced on SLA surfaces. Inhibition of β‐catenin mediated transcription by dnTCF in murine osteoblastic MC3T3 cells, reversed the effects of topography on cell differentiation. Taken together, these results show that surface roughness modulates the responsiveness of mesenchymal cells to Wnt3a, that this requires the control of β‐catenin degradation, and that the control of β‐catenin signaling by surface topography is accountable for at least part of the effects of surface on cell differentiation. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
In vitro hydrolytic and enzymatic degradation of nestlike‐patterned electrospun poly(D,L‐lactide‐co‐glycolide) scaffolds
Authors: Zhou Xuegang , Cai Qing , Yan Na , Deng Xuliang , Yang Xiaoping 
Published: August 2010

AbstractA common problem in applying electrospun biodegradable polyester matrixes as tissue‐engineering scaffolds is their serious shrinkage with degradation to reduce the porosity drastically. To ameliorate this problem, a nestlike‐patterned poly(D,L‐lactide‐co‐glycolide) (PLGA) nanofibrous (∼900 nm) matrix was proposed and fabricated by electropinning. Shrinkage studies demonstrated that the dimension change of nestlike‐patterned fibrous membrane was much smaller than those of nonwoven and parallel‐aligned fibrous membranes. And the robust framework of the patterned matrix helped to maintain its original nestlike topographical structure during degradation. Compared to hydrolytic‐degraded specimens, the PLGA nanofibrous matrixes degraded in the presence of lysozyme showed larger weight loss but slower decrease in molecular weight. Besides, porous fibers with intact surface were detected by scanning electron microscopy after 20‐week hydrolysis, and fibers with pores both inside and on surface were observed after enzymatic degradation for 12 weeks. Accordingly, the former presented a bimodal gel permeation chromatography (GPC) peak, while no bi or multimodal GPC peaks were found for the latter as degradation proceeded. These results indicated that an acid autocatalytic effect still existed in the hydrolysis of PLGA nanofibrous matrix. The presence of lysozyme could only accelerate the dissolution of degradation products with low molecular weight, but have no contribution to the chain scission. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Effects of VEGF loading on scaffold‐confined vascularization
Authors: Lindhorst Daniel , Tavassol Frank , von See Constantin , Schumann Paul , Laschke Matthias W. , Harder Yves , Bormann Kai‐Hendrik , Essig Harald , Kokemüller Horst , Kampmann Andreas , Voss André , Mülhaupt Rolf , Menger Michael D. , Gellrich Nils‐Claudius , Rücker Martin 
Published: August 2010

AbstractAdequate vascularization of tissue‐engineered constructs remains a major challenge in bone grafting. In view of this, we loaded ß‐tricalcium‐phosphate (ß‐TCP) and porous poly(L‐lactide‐co‐glycolide) (PLGA) scaffolds via collagen coating with vascular endothelial growth factor (VEGF) and studied whether the VEGF loading improves scaffold angiogenesis and vascularization. Dorsal skinfold chambers were implanted into 48 balb/c mice, which were assigned to 6 groups (n = 8 each). Uncoated (controls), collagen‐coated, and additionally VEGF‐loaded PLGA and ß‐TCP scaffolds were inserted into the chambers. Angiogenesis, neovascularization, and leukocyte‐endothelial cell interaction were analyzed repeatedly during a 14‐day observation period using intravital fluorescence microscopy. Furthermore, VEGF release from PLGA und ß‐TCP scaffolds was studied by ELISA. Micromorphology was studied from histological specimens. Unloaded ß‐TCP scaffolds showed an accelerated and increased angiogenic response when compared with unloaded PLGA scaffolds. In vitro, PLGA released significantly higher amounts of VEGF compared with ß‐TCP at the first two days resulting in a rapid drop of the released amount at the following days up to day 7 where the VEGF release was negligible. Nonetheless, in vivo VEGF loading increased neovascularization, especially in ß‐TCP scaffolds. This increased vascularization was associated with a temporary leukocytic response with pronounced leukocyte‐endothelial cell interaction at days 3 and 6. Histology revealed adequate host tissue response and engraftment of both ß‐TCP and PLGA scaffolds. Our study demonstrates that ß‐TCP scaffolds offer more suitable conditions for vascularization than PLGA scaffolds, in particular if they are loaded with VEGF. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
In‐vitro dissolution of magnesium–calcium binary alloys: Clarifying the unique role of calcium additions in bioresorbable magnesium implant alloys
Authors: Kirkland Nicholas T. , Birbilis Nick , Walker Jemimah , Woodfield Tim , Dias George J. , Staiger Mark P. 
Published: August 2010

AbstractA systematic investigation of a series of magnesium–calcium binary alloys is presented to reveal the influence of increasing calcium (Ca) additions on the in vitro degradation of magnesium (Mg). Because of its prevalence in structural tissues, Ca is among the most biologically viable additions to orthopedic‐intended Mg‐based biomaterials. Hence, a fundamental electrochemical study of Ca additions to Mg biomaterials is essential to its continued role as an alloying addition. In this work, in vitro degradation conditions closer to the physiological environment were implemented through the addition of proteins to simulated body fluid and maintenance of a constant pH, with tests conducted using Hanks solution, minimum essential medium (MEM), and MEM containing fetal bovine serum. Alloying with Ca leads to the formation of Mg2Ca intermetallic particles that result in systematically enhanced dissolution kinetics. This observation is rationalized via microelectrochemical tests upon the Mg2Ca intermetallic in isolation, which reveals rapid anodic kinetics. Hence, the extent of Mg‐Ca alloy dissolution can be modified depending on the amount of Mg2Ca present, suggesting that Ca can be deployed as a functional addition capable of not only enhancing biodissolution of the alloy, but being able to do this in a systematic, controllable manner depending on its volume fraction. In addition, up to a 3‐fold reduction in the corrosion rate is observed with corrosion testing in an albumin‐containing medium when compared to Hanks solution, the results highlighting that the use of a physiologically “correct” medium is essential for the in vitro screening of Mg‐based alloys suitable for orthopaedic applications. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Novel three‐dimensional scaffolds of poly(L‐lactic acid) microfibers using electrospinning and mechanical expansion: Fabrication and bone regeneration
Authors: Shim In Kyong , Jung Mi Ra , Kim Kyung Hwa , Seol Yang Jo , Park Yoon Jeong , Park Won Ho , Lee Seung Jin 
Published: August 2010

AbstractPoly(L‐lactic acid) (PLLA) microfibrous scaffolds with three‐dimensional (3D) structures were fabricated using an electrospinning technique with a subsequent mechanical expansion process. To achieve a 3D fibrous structure, the fusion at the contact points of the as‐spun PLLA microfibers was avoided using an appropriate binary solvent system of methylene chloride and acetone. The solvent composition was optimized based on the solvent power, volatility, and viscosity (methylene chloride:acetone = 9:1 volume ratio). The final 3D structure of the electrospun scaffolds was obtained after mechanical expansion of the electrospun microfibrous mats. The pore sizes of the scaffolds were controlled by varying the degree of expansion of the nonbonded microfibrous mats, and they were in the range of several microns up to 400 μm. The 3D scaffolds were examined for their morphological properties and their potential use for the proliferation of osteoblasts. Generally recognized electrospun 2D nanofibrous membranes were also tested in order to compare the cell behaviors using different scaffold geometries. The 3D scaffolds demonstrated a high level of osteoblast proliferation (1.8‐fold higher than nanofibrous membranes in a week). The osteoblasts actively penetrated the inside of the 3D scaffold and showed a spatial cell distribution, as confirmed by SEM and H&E staining, while a monolayer formed in the case of the 2D nanofibrous membranes with limited cell infiltration. In vivo results further showed that 3D electrospun microfibrous matrices were a favorable substrate for cell infiltration and bone formation after 2 and 4 weeks, using a rabbit calvarial defect model. In this study, the 3D microfibrous PLLA scaffolds fabricated using electrospinning techniques might be an innovative addition to tissue engineering applications. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.