bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and development of anti‐chitosan antibodies
Authors: Sorlier Pierre , Hartmann Daniel J. , Denuzière Anne , Viton Christophe , Domard Alain 
Published: November 2003

AbstractPolyclonal antibodies directed against chitosan were produced using several immunogens, prepared by binding the polymer according to two ways (covalent and electrostatic) with a protein (bovine serum albumin or hemocyanin). It appeared that the presence of a carrier protein linked to chitosan was necessary to enhance the immune response and to obtain antibodies in a stable and reproducible way. Direct and inhibition enzyme‐linked immunosorbent assay experiments were performed to assess the affinity and the specificity of the antibodies. The interactions of these antibodies with modified chitosans showed no influence of the degree of polymerization of the polymer in the range studied (from 24 to 2261), by contrast with the degree of acetylation. The affinity decreased when the degree of acetylation increased. Absence of cross‐reactivity with glycosaminoglycans was observed whatever the antibody. The cationicity of the amine function along the polymer chains may have a role in the immunological recognition of the chitosan structure. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 766–774, 2003
Quantitative assessment of collagen assembly by live cells
Authors: Johnson Chad , Galis Zorina S. 
Published: November 2003

AbstractChanges in supramolecular assembly of matrix, specifically collagen, have important functional consequences, especially for tissues requiring high mechanical strength. Thus modulation of collagen assembly could be used as a therapeutic intervention or to control the development of tissue‐engineered constructs containing natural matrix. Quantitative methods that monitor such effects currently are lacking. Using live cultured cells, we developed a convenient way either to visualize by fluorescence microscopy or to measure directly, using a high throughput fluorescence assay, the supramolecular assembly of FITC‐labeled collagen monomers. The wide applicability of this assay was confirmed by testing the assay using two major collagen sources, rat tail and bovine skin, and vascular smooth muscle cells from two different origins, mouse aorta and human saphenous vein. We further determined that treatments that interfere with the function of the cytoskeleton modulate collagen assembly. Use of positive and negative regulators of lysyl‐oxidase indicated that while the assay does not require active production of endogenous collagen, it can be used to monitor the incorporation of such de novo synthesized collagen into labeled fibrils. Thus we have designed a novel quantitative assay that can monitor assembly of exogenous and endogenous collagen by live cells and reveal the effects of various interventions upon this process. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 775–784, 2003
Mechanical properties and Young's modulus of plasma‐sprayed hydroxyapatite coating on Ti substrate in simulated body fluid
Authors: Yang Y. C. , Chang Edward , Lee S. Y. 
Published: November 2003

AbstractThis study evaluated the Young's modulus, residual stress and strain, bonding strength, and microstructure of the plasma‐sprayed hydroxyapatite coating (HAC) on Ti6Al4V substrate with and without immersion in Hank's balanced salt solution (HBSS). The purpose was to explore the possible correlation of HAC durability and mechanical properties of the coating. The results show that the residual stress and strain, Young's modulus, and bonding strength of the HAC after immersion in HBSS are substantially decreased. The decayed Young's modulus and mechanical properties of HACs are accounted for by the degraded interlamellar or cohesive bonding in the coating due to the increased porosity after immersion that weakens the bonding strength of coating and substrate system. The biologic implications of the research are discussed in detail. This study contributes to the arguments that the method to alleviate the dissolution of HAC will increase the bonding strength of the coating system after immersion, which together with the controlled residual stress and strain in the coating might promote the long‐term stability of the HA‐coated implant. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 886–899, 2003
Preparation, degradation, and calcification of biodegradable polyurethane foams for bone graft substitutes
Authors: Gorna Katarzyna , Gogolewski Sylwester 
Published: November 2003

AbstractAutogenous cancellous bone graft is used to heal critical‐size segmental long bone defects and defects in the maxillofacial skeleton. Harvesting of bone graft is traumatic, causes morbidity of the donor site, and often results in complications. Thus, there is a need for new biologically functional bone graft substitutes that, instead of autogenous bone graft, could be used to facilitate bone regeneration in critical‐size defects. Porous biodegradable elastomeric polyurethane scaffolds combined with the patient's own bone marrow could potentially be such bone substitutes. The elastomeric bone substitute prevents shear forces at the interface between bone and rigid, e.g., ceramic bone substitutes and establishes an intimate contact with the native bone ends, thus facilitating the proliferation of osteogenic cells and bone regeneration. Crosslinked 3D biodegradable polyurethane scaffolds (foams) with controlled hydrophilicity for bone graft substitutes were synthesized from biocompatible reactants. The scaffolds had hydrophilic‐to‐hydrophobic content ratios of 70:30, 50:50, and 30:70. The reactants used were hexamethylene diisocyanate, poly(ethylene oxide) diol (MW = 600) (hydrophilic component), and poly(ϵ‐caprolactone) diol (Mw = 2000), amine‐based polyol (Mw = 515) or sucrose‐based polyol (Mw = 445) (hydrophobic component), water as the chain extender and foaming agent, and stannous octoate, dibutyltin dilaurate, ferric acetylacetonate, and zinc octoate as catalysts. Citric acid was used as a calcium complexing agent, calcium carbonate, glycerol phosphate calcium salt, and hydroxyapatite were used as inorganic fillers, and lecithin or solutions of vitamin D3 were used as surfactants. The scaffolds had an open‐pore structure with pores whose size and geometry depended on the material's chemical composition. The compressive strengths of the scaffolds were in the range of 4–340 kPa and the compressive moduli in the range of 9–1960 kPa, the values of which increased with increasing content of polycaprolactone. Of the two materials with the same amount of polycaprolactone the compressive strengths and moduli were higher for the one containing inorganic fillers. The scaffolds absorbed water and underwent controlled degradation in vitro. The amount of absorbed water and susceptibility to degradation increased with the increasing content of the polyethylene oxide segment in the polymer chain and the presence in the material of calcium complexing moiety. All polyurethane scaffolds induced the deposition of calcium phosphate crystals, the structure and calcium:phosphorus atomic ratio of which depended on the chemical composition of the polyurethane and varied from 1.52–2.0. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 813–827, 2003
Dimensional changes in acid‐demineralized dentin matrices following the use of HEMA–water versus HEMA–alcohol primers
Authors: Eddleston C. L. , Hindle A. R. , Agee K. A. , Carvalho R. M. , Tay F. R. , Rueggeberg F. A. , Pashley D. H. 
Published: November 2003

AbstractAlthough dried acid‐etched dentin can be reexpanded by hydroxyethyl methacrylate (HEMA)/water primers, the primed dentin collapses when the water is evaporated. Experimental HEMA/alcohol primers should stiffen the matrix and permit less shrinkage when the solvent is evaporated. The purpose of this study was to test the hypotheses that matrix shrinkage induced by solvent evaporation from HEMA primers is inversely related to solvent‐induced matrix stiffness. Dentine discs were prepared from midcoronal dentine of unerupted human third molars. After demineralization in 37% phosphoric acid, the specimens were placed in the well of a linear variable differential transformer instrument, which measures changes in the matrix height and stiffness by load displacement after the application of weights. This was done in their hydrated state after water had been applied, after drying with dry nitrogen gas, and after the application of 35 vol % HEMA–water, HEMA–methanol, HEMA–ethanol, or HEMA–propanol primers. The degree of reexpansion after the application of the primers to the dentine in the dried state was found to be highest using the HEMA–water primer, followed by HEMA–methanol and HEMA–ethanol, with the HEMA–propanol primer producing no expansion. However, when the solvents were evaporated the HEMA–water‐treated specimens shrank the most, the HEMA–ethanol‐treated specimens shrank an intermediate amount, and the HEMA–methanol‐treated specimens shrank the least. The net result of expansion minus shrinkage produced by evaporation determines how much HEMA remains in the hybrid layer just prior to polymerization. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 900–907, 2003
Material‐induced tissue factor expression but not CD11b upregulation depends on the presence of platelets
Authors: Gorbet M. B. , Sefton M. V. 
Published: November 2003

AbstractBiomaterials activate leukocytes as well as platelets when exposed to blood. One feature of leukocyte activation at least at times beyond a few hours is tissue factor expression, contributing to a procoagulant state. We show here that platelet activation and specifically platelet–monocyte aggregate formation appears to be a precondition for tissue factor expression. Material‐induced Tissue Factor (TF) expression by isolated leukocytes (6 × 106 cells/mL) resuspended in increasing concentrations of platelets in plasma was elevated when the platelet concentration was 50 × 106 platelets/mL or more; at lower platelet concentrations (1–25 × 106 · cells/mL) the TF expression remained at background levels. On the other hand, significant CD11b upregulation was observed on leukocytes, in bulk and adherent to beads, at all platelet concentrations. This platelet effect on material‐induced TF expression appeared to be mediated by the formation of platelet–monocyte aggregates. Anti‐P‐selectin, which blocked the association between platelets and leukocytes, reduced monocyte adhesion and material‐induced TF expression for bulk monocytes. Anti‐GPIIb/IIIa, a GPIIb/IIIa platelet antagonist, also reduced monocyte adhesion and material‐induced TF expression in the bulk, most likely due to its inhibiting effect on the formation of platelet–monocyte aggregates, secondary to platelet activation. However, the antibody‐associated reductions for bulk leukocytes (mainly neutrophils) were small and incomplete. Similar levels of TF expression, in the bulk, were observed with both polystyrene (PS), a strong platelet activator, and polyethylene glycol‐modified PEG (PS‐PEG), a mild platelet activator. The role of platelets in material‐induced TF expression appears to be mediated in part via the formation of platelet–monocyte aggregates, although other mechanisms are likely also involved. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 792–800, 2003
Increased osteoblast adhesion on titanium‐coated hydroxylapatite that forms CaTiO3
Authors: Webster Thomas J. , Ergun Celaletdin , Doremus Robert H. , Lanford William A. 
Published: November 2003

AbstractCaTiO3 is a strong candidate to form at the interface between hydroxylapatite (HA) and titanium implants during many coating procedures. However, few studies have compared the cytocompatibility properties of CaTiO3 to HA pertinent for bone–cell function. For this reason, the objective of the present in vitro study was to determine the ability of bone‐forming cells (osteoblasts) to adhere on titanium coated with HA that resulted in the formation of CaTiO3. To accomplish the formation of CaTiO3, titanium was coated on HA discs and annealed either under air or a N2+H2 environment. Materials were characterized by X‐ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), and atomic force microscopy (AFM). These characterization techniques demonstrated the formation of a nanometer rough CaTiO3 layer as a consequence of interactions between HA and titanium during coating conditions. Results from cytocompatibility tests revealed increased osteoblast adhesion on materials that contained CaTiO3 compared to both pure HA and uncoated titanium. The greatest osteoblast adhesion was observed on titanium‐coated HA annealed under air conditions. Because adhesion is a crucial prerequisite to subsequent functions of osteoblasts (such as the deposition of calcium containing mineral), the present in vitro results imply that orthopedic coatings that form CaTiO3 could increase osseointegration with juxtaposed bone needed for increased implant efficacy. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 975–980, 2003
The effect of silica‐containing calcium‐phosphate particles on human osteoblasts in vitro
Authors: Phan Phong V. , Grzanna Mark , Chu James , Polotsky Anna , El‐Ghannam Ahmed , Van Heerden David , Hungerford David S. , Frondoza Carmelita G. 
Published: November 2003

AbstractThere is an ongoing need for more effective and less costly bone substitutes. It has previously been proposed that silica‐containing bioactive glass would be more effective as a bone repair material because of its physiochemical properties. Three newly synthesized silica‐containing bioactive glass formulations, HA‐31 (25%), HA‐11 (50%), and HA‐13 (75%), were tested as biocompatible substrates for the continued proliferation and phenotype expression of human bone cells in vitro. Two currently available bioactive glasses (BioGlass®, Hydroxyapatite) served as comparisons. The biocompatibility of these bioglasses, as well as their osteoconductive properties, was assessed by employing primary cultures of human osteoblasts and human synoviocytes for 4 days. The results obtained demonstrated that the three new bioglasses enhanced the proliferative response of osteoblasts compared with osteoblasts cultured alone. Reverse Transcription Polymerase Chain Reaction (RT‐PCR) analysis indicated that osteoblasts retained their phenotypic expression by continued expression of collagen type I and alkaline phosphatase. The newly synthesized preparations of silica‐containing bioactive glass did not induce stimulation of proinflammatory markers iNOS and IL‐1β in synoviocytes. In conclusion, the newly synthesized silica‐containing bioactive glasses are biocompatible substrate for bone‐forming osteoblasts. However, the formulations tested did not show significant advantage over the currently available bioactive glasses in vitro. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 1001–1008, 2003
Metal ions alter lipopolysaccharide‐induced NFκB binding in monocytes
Authors: Lewis J. B. , Wataha J. C. , Randol T. M. , McCloud V. V. , Lockwood P. E. 
Published: November 2003

AbstractMetals are components of a variety of biomaterials used in orthopedic and dental appliances; however, their biocompatibility with the surrounding tissues is not completely understood. Monocytes are important immune cells that respond to inflammatory stimuli by rapidly producing a variety of inflammatory proteins. Regulation of this response often involves activation of the transcription factor NFκB. The current study was designed to determine whether monocyte activation of NFκB in response to bacterial lipopolysaccharide (LPS) is affected by pretreatment with metal ions. Concentrations of metal ions that affected cell number after 24 h of exposure were first determined. Then THP‐1 human monocytes were cultured for 2 h in media containing metal ions at concentrations below levels that altered cell growth. Parallel cultures were treated with 10 μg/mL Escherichia coli LPS, and all samples were cultured an additional 2 h. Nuclear proteins were extracted and normalized amounts were incubated with [32P]‐end‐labeled NFκB consensus oligonucleotide. NFκB–DNA complexes were identified and quantified by electrophoretic mobility shift analysis. The extent of NFκB–DNA complex formation after metal ion pretreatment with or without LPS induction was compared to no treatment or LPS‐only treated controls. Finally, LPS‐induced IL1β secretion was measured from palladium‐treated and control cells. Concentrations were identified for each metal ion (Ag+, Co2+, Cu2+, Hg2+, Ni2+, and Pd2+) that did not reduce cell number after 24 h of exposure (ranging from 5 μM for Ag+ and Hg2+ to 200 μM for Ni2+). Exposures of 2 h at these concentrations did not alter cell morphology, staining with trypan blue, or cell number. LPS exposure had no effect on cell number with or without metal ions after 2 h. When metal treatment alone was assessed, none of the metal ions had a significant effect on NFκB–DNA binding. However, pretreatment with Co2+, Ni2+, Ag1+, Hg2+, and Pd2+ significantly decreased NFκB–DNA binding by 40–70% versus LPS alone. Only Cu2+ had no effect on LPS‐induced NFκB–DNA complex formation. Pd2+ lowered, but did not abolish, IL1β secretion at concentrations comparable to those that altered NFκB–DNA binding. These results suggest that many commonly used metals alter monocyte function at concentrations that are not overtly toxic, and that protein levels controlled in part by NFκB also may be altered. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 868–875, 2003
Porosity of porcine bladder acellular matrix: Impact of ACM thickness
Authors: Farhat Walid , Chen Jun , Erdeljan Petar , Shemtov Oren , Courtman David , Khoury Antoine , Yeger Herman 
Published: November 2003

AbstractThe objectives of this study are to examine the porosity of bladder acellular matrix (ACM) using deionized (DI) water as the model fluid and dextran as the indicator macromolecule, and to correlate the porosity to the ACM thickness. Porcine urinary bladders from pigs weighing 20–50 kg were sequentially extracted in detergent containing solutions, and to modify the ACM thickness, stretched bladders were acellularized in the same manner. Luminal and abluminal ACM specimens were subjected to fixed static DI water pressure (10 cm); and water passing through the specimens was collected at specific time interval. While for the macromolecule porosity testing, the diffusion rate and direction of 10,000 MW fluoroescein‐labeled dextrans across the ACM specimens mounted in Ussing's chambers were measured. Both experiments were repeated on the thin stretched ACM. In both ACM types, the fluid porosity in both directions did not decrease with increased test duration (3 h); in addition, the abluminal surface was more porous to fluid than the luminal surface. On the other hand, when comparing thin to thick ACM, the porosity in either direction was higher in the thick ACM. Macromolecule porosity, as measured by absorbance, was higher for the abluminal thick ACM than the luminal side, but this characteristic was reversed in the thin ACM. Comparing thin to thick ACM, the luminal side in the thin ACM was more porous to dextran than in the thick ACM, but this characteristic was reversed for the abluminal side. The porcine bladder ACM possesses directional porosity and acellularizing stretched urinary bladders may increase structural density and alter fluid and macromolecule porosity. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 970–974, 2003
Risks and responses among the urban poor in India
Authors: Kantor Paula , Nair Padmaja 
Published: November 2003

AbstractThis paper describes the events faced by urban poor households in Lucknow, India and household responses in the face of these events. Using household and individual data collected in 2002 from 12 slum settlements, the authors found that certain events, such as illness and social and religious spending, are more frequent than others and that some groups, characterized by gender of head of household, community and economic status, experience certain event types more than others. It also found that some less frequent events may be very burdensome due to their high severity. Responses to common event types exhibited a pattern. Households reduced consumption, used savings and took loans much more frequently than other options, across event types. Variations in responses were identified by event type and severity and economic status. The results illustrate the need for both protective and promotive interventions to improve livelihood security among the urban poor. Copyright © 2003 John Wiley & Sons, Ltd.
Aid and public sector borrowing in developing countries
Authors: Feeny Simon , McGillivray Mark 
Published: November 2003

AbstractThis paper analyses the relationship between public sector borrowing and foreign development aid. It is concerned specifically with the public sector borrowing requirement net of aid, questioning the assumption that aid and this type of borrowing are substitutes for one another. After looking at the public sector budget constraint and various conditions under which aid might lead to an increase in this borrowing, the paper surveys the empirical results of literature on aid and public sector fiscal behaviour. It finds that the results of a number of studies are consistent with aid leading to increases in this borrowing. Further investigation, in the form of econometric analysis of panel data, also points to this outcome. Copyright © 2003 John Wiley & Sons, Ltd.
International trade in ‘quality goods’: signalling problems for developing countries
Authors: Hudson John , Jones Philip 
Published: November 2003

AbstractConsumers evaluate product quality with information signals such as brand name giving an advantage to established firms over other firms even when introducing a new product. Another signal is ‘country of origin’ and, as high‐income countries focus more heavily on higher quality goods, there is a tendency for consumers to associate quality with a country's income per capita. Thus new firms from developing countries face particular problems in export markets. International standardization offers a potential solution to their problem. However, analysis of the use of ISO 9000 suggests that it is difficult to eliminate the informational asymmetry. Copyright © 2003 John Wiley & Sons, Ltd.
From microcredit to microfinance: evolution of savings products by MFIs in Bangladesh
Authors: Dowla Asif , Alamgir Dewan 
Published: November 2003

AbstractThis paper chronicles how the microfinance industry in Bangladesh has evolved from its initial focus on credit, disbursing standardized loan products and collecting obligatory savings to the development of flexible savings products. We describe the process through which the industry gradually moved away from compulsory savings and introduce flexible savings. We provide detailed descriptions of various savings related products used by MFIs in Bangladesh. We point out the numerous problems that can arise when MFIs collects savings especially from non‐members without a proper legal framework. We conclude the paper by suggesting prudent regulation of MFIs to ensure the security of the meager savings of the poor. Copyright © 2003 John Wiley & Sons, Ltd.
Causes of inequalities in China, 1952 to 1999
Authors: Bhalla Ajit S. , Yao Shujie , Zhang Zongyi 
Published: November 2003

AbstractThis paper presents a comprehensive picture of inequality in China on the basis of provincial data. It decomposes overall inequalities into intra and inter components. Rural–urban inequality dominated overall inequality in the past and will continue to do so in the future. Meanwhile, in recent years inter‐regional inequality has grown rapidly and become an important component of inequality. We find that the pattern of inequality is quite different in the pre‐reform and reform periods. Our results show that overall inequality in China is large by international standards and that it has grown worse during the past half century. Copyright © 2003 John Wiley & Sons, Ltd.