bluuebunny/crossref_metadata_2025_split huggingface dataset:
Local carboplatin delivery and tissue distribution in livers after radiofrequency ablation
Authors: Szymanski‐Exner A. , Gallacher A. , Stowe N. T. , Weinberg B. , Haaga J. R. , Gao J. 
Published: October 2003

AbstractThis study investigated the local drug pharmacokinetics of intralesional drug delivery after radiofrequency ablation of the liver. We hypothesized that the tissue architecture damaged by the ablation process facilitates the drug penetration in the liver and potentially enlarges the therapeutic margin in the local treatment of cancer. The delivery rate and tissue distribution of carboplatin, an anticancer agent, released from poly(D,L‐lactide‐co‐glycolide) implants into rat livers after radiofrequency ablation were quantified by atomic absorption spectroscopy. Results showed that carboplatin clearance through blood perfusion was significantly slower in the ablated livers, leading to a more extensive tissue retention and distribution of the drug. The concentration of Pt at the implant–tissue interface ranged from 234 to 1440 μg Pt/(g liver) in the ablated livers over 144 h versus 56 to 177 μg Pt/(g liver) in the normal tissue. The maximum penetration distance at which Pt level reached above 6 μg/g (calculated based on a reported IC90 value for carboplatin) was 8–10 mm and 4–6 mm in ablated and normal liver, respectively. Histological analysis of the necrotic lesions showed widespread destruction of tissue structure and vasculature, supporting the initial hypothesis. This study demonstrated that intralesional drug delivery could provide a sustained, elevated concentration of anticancer drug at the ablation boundary that has the potential to eliminate residual cancer cells surviving radiofrequency ablation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 510–516, 2003
Effect of increasing silver content in phosphate‐based glasses on biofilms of Streptococcus sanguis
Authors: Mulligan A. M. , Wilson M. , Knowles J. C. 
Published: October 2003

AbstractSilver is a powerful antibacterial ion that may be useful for dealing with localized infections, such as periodontitis. However, the use of silver in this role could be significantly improved by the development of an effective means of delivery. Phosphate‐based glasses may provide a means of delivering the ions in a controlled manner. In our study, we have examined the effect of increasing silver content in phosphate‐based glasses on biofilms of Streptococcus sanguis. Glasses of nominally the same dissolution rate were doped with silver at 1, 5,10, and 15 mol % and the number of colony‐forming units (CFUs) determined after 6 and 24 h in a constant depth film fermenter (CDFF). The 1 mol % silver showed little change between 6 and 24 h. However, only 0.5 log CFUs were present on the glass containing 5 mol % at 6 h, and this reduced to virtually zero at 24 h. Few viable bacteria were found on the 10 mol % glass at both 6 and 24 h. The 15 mol % glass was investigated in this experiment, but no viable counts were detected. In a second set of experiments, glasses with 10 and 15 mol % silver were tested in the CDFF for up to 192 h. For the 10 mol % silver glass, there was ∼0.8 log CFUs on this glass, which dropped to almost zero at 50 h. This was approximately 1.5–2.0 log reduction in CFUs compared to controls, and this difference was maintained for the first 50 h. After 50 h, there was a slow increase in the CFUs on all samples. However, CFUs on the 10 mol % silver glass were still suppressed up to 192 h compared to the controls. However, both controls also exhibited a decrease in viable counts at 50 h; this may have been due to carryover of silver into the control sample holders. However, this was minimized by the specimen layout in the CDFF and by having gaps between specimen sets. For the 15 mol % silver glass, counts for both this glass and the controls decreased to virtually zero between 24 and 48 h, but the numbers slowly increased up to 170 h, but the number of CFUs was suppressed compared to the 10 mol % glass at the same time point. The decrease seen is clearly the effect of the silver ions; however, the slow increase in CFUs may be accounted for by the biofilms forming thick layers on top of the glass discs inhibiting the release of ions from the glass by forming a “sacrificial layer” through which further ions have to diffuse. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 401–412, 2003
Fatigue and fracture toughness of acrylic bone cements modified with long‐chain amine activators
Authors: Deb S. , Lewis G. , Janna S. W. , Vazquez B. , San Roman J. 
Published: October 2003

AbstractThe composition of acrylic bone cement has been identified as one of the important parameters affecting its mechanical properties and may, in turn, ultimately influence the longevity of a cemented arthroplasty. Our aim in this study was to determine the influence of change of one compositional variable, the activator, on the fatigue performance and fracture toughness of specimens of the fully cured cement. To that end, three sets of cements were prepared, containing either the conventional activator, 4‐N,N dimethyl p‐toluidine (DMPT), or novel ones that are tertiary amines based on long‐chain fatty acids, that is, 4‐N,N dimethylaminobenzyl oleate (DMAO) and 4‐N,N dimethylaminobenzyl laurate (DMAL). In the fatigue tests, the specimens were subjected to tension–tension loading, and the results (number of cycles to failure, Nf) were analyzed using the linearized form of the three‐parameter Weibull equation. The fracture toughness (KIc) tests were conducted with rectangular compact tension specimens. All fracture surfaces were subsequently examined with scanning electron microscopy. We found that the Weibull mean fatigue lives for specimens fabricated using the DMPT, DMAL, and DMAO containing cements were 272,823, 453,551, and 583,396 cycles, respectively. The corresponding values for KIc were 1.94 ± 0.05, 2.06 ± 0.09, and 2.00 ± 0.07 MPa√m, respectively. Statistical analyses showed that for both the DMAL‐ and DMAO‐containing cements, the mean values of Nf were significantly higher compared to the corresponding value for the DMPT‐containing cement (Mann–Whitney test; α < 0.10). This result is attributed to the higher molecular weights of the former cements compared to the latter. The same trend was found for the mean KIc values (Mann–Whitney test; α < 0.05), with the trend being explained in terms of the differences seen in the crack morphologies. These results thus demonstrate that these novel amines are viable alternatives to DMPT for incorporation into acrylic bone cement formulations in the future. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 571–577, 2003
Electrical polarization of bioactive glass and assessment of their in vitro apatite deposition
Authors: Obata Akiko , Nakamura Satoshi , Moriyoshi Yusuke , Yamashita Kimihiro 
Published: October 2003

AbstractWe evaluated the electrical polarizability of a bioactive glass of the 45S5 type (BG) by thermally stimulated depolarization current (TSDC) measurement based on the effects of the surface charges generated by an electrical polarization treatment on the growth of calcium phosphate crystals in simulated body fluid (SBF). From the results of the TSDC measurements, the polarized BG showed broad peaks in the depolarization current density spectra. The stored electrical charges calculated from the TSDC measurements of the BG polarized with an electrical dc field of 10 V · cm−1 at 500°C for 1 h was 8.5 mC · cm−2 and depended on the electrical dc field intensity. The depolarization of the BG was assumed to be due to a migration of sodium ions and influenced by transitions of the BG structure. The immersion tests with the SBF showed that the effects of the electrical polarization produced morphologic changes in the calcium phosphate deposit grown on the BG after the short period of 2 h. We expected the effects to be caused by a change in the ion concentrations in the surrounding SBF due to the surface charges of the polarized BG. The change in the ion concentrations induced the difference in the calcium phosphate deposition. Consequently, we confirmed that BG had an electrical polarizability, a possibility of storing large charges, and differences in the growth of the calcium phosphate deposit due to the effects of the surface charges. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 413–420, 2003
Protein adsorption and smooth muscle cell adhesion on biodegradable agmatine‐modified poly(propylene fumarate‐co‐ethylene glycol) hydrogels
Authors: Tanahashi Kazuhiro , Mikos Antonios G. 
Published: October 2003

AbstractWe synthesized positively charged biodegradable hydrogels from poly(propylene fumarate‐co‐ethylene glycol) block copolymer and agmatine‐modified poly(ethylene glycol)‐tethered fumarate by radical crosslinking, and investigated the effect of the guanidino group of agmatine on vascular smooth muscle cell adhesion and protein adsorption to the hydrogels. In the presence of serum, the number of adherent smooth muscle cells per unit surface area increased dose‐dependently from 15 to 75% of the initial seeding density at 20 h as the initial agmatine‐modified monomer content increased from 0 to 200 mg/g. Cell spreading also depended on the initial monomer content. In the absence of serum, the number of adherent cells per unit surface area increased slightly from 10 to 17% of the initial seeding density as the initial monomer content increased from 0 to 200 mg/g. Cell adhesion increased significantly by adding exogenous vitronectin to serum‐free medium, whereas exogenous fibronectin addition did not enhance cell adhesion. The enzyme‐linked immunosorbent assay of fibronectin and vitronectin adsorbed onto the hydrogels revealed that the incorporation of positive charges into the hydrogels enhanced vitronectin, but not fibronectin, adsorption significantly. These results suggest that the guanidino group of agmatine enhanced cell adhesion by promoting the adsorption of serum components, and vitronectin may be one of the components. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 448–457, 2003
Modification of Ti6Al4V surfaces using collagen I, III, and fibronectin. I. Biochemical and morphological characteristics of the adsorbed matrix
Authors: Bierbaum Susanne , Beutner René , Hanke Thomas , Scharnweber Dieter , Hempel Ute , Worch Hartmut 
Published: October 2003

AbstractStudies in developmental and cell biology have established the fact that responses of cells are influenced to a large degree by morphology and composition of the extracellular matrix. Goal of this work is to use this basic principle to improve the biological acceptance of implants by modifying the surfaces with components of the extracellular matrix (ECM). Aiming at load‐bearing applications in bone contact, in this study the modification of titanium surfaces with the collagen types I and III in combination with fibronectin was undertaken; fibrillogenesis, fibril morphology and adsorption of type I, III and I/III‐cofibrils onto titanium were assessed. Increasing the collagen type III amount resulted in a decrease of fibril diameter, while no significant changes in adsorption could be detected. The amount of fibronectin bound to the heterotypic fibrils depended on fibrillogenesis parameters such as ionic strength or concentration of phosphate, and varied with the percentage of integrated type III collagen. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 421–430, 2003
Interactions of heparin with human skin cells: Binding, location, and transdermal penetration
Authors: Parisel Claire , Saffar Line , Gattegno Liliane , André Valérie , Abdul‐Malak Nabil , Perrier Eric , Letourneur Didier 
Published: October 2003

AbstractThe development of new materials for tissue engineering of skin substitutes requires an increasing knowledge of their interactions with human skin cells. Since carbohydrate recognition is involved in numerous biologic processes, including skin regeneration, the aim of this study was to identify sugar receptors expressed at the surface of human dermic and epidermic cells. Binding of fluorescent sugar–polyhydroxyethylacrylamide derivatives was analyzed by flow cytofluorimetry on cultured human skin fibroblasts, keratinocytes, and melanocytes. We observed that these three cell types express a membrane receptor specific for GlcNAc6S. Since the polysaccharide heparin contains this sugar moiety, we further investigated the interactions of heparin with skin cells. We analyzed the in vitro cell binding and ex vivo diffusion with the Franz cell of heparin and of two other polysaccharides of similar molecular weight, dextran and chondroitin sulfate. We found evidence of the preferential binding of heparin on keratinocytes and its high transcutaneous penetration of skin. Altogether, our results describe the affinity of heparin for human skin cells and suggest it may be an excellent candidate for use in the skin delivery of drugs or cosmetics and also as an active component in engineered skin. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 517–523, 2003
Bridging a 30‐mm nerve defect using collagen filaments
Authors: Yoshii Satoru , Oka Masanori , Shima Mitsuhiro , Taniguchi Ataru , Akagi Masao 
Published: October 2003

AbstractThis article describes a 30‐mm regeneration of severed peripheral nerve axons along collagen filaments. Two thousand or 4000 31‐mm‐long collagen filaments were grafted to bridge a 30‐mm defect of the rat sciatic nerve. A collagen tube was grafted as a control. The mean number and mean fiber diameter of regenerated myelinated axons were 330 ± 227 and 2.7 ± 0.9 μm in the distal end of the 2000 collagen‐filaments nerve guide, and 564 ± 275 and 2.5 ± 1.1 μm in the distal end of the 4000 collagen‐filaments nerve guide at 12 weeks postoperatively, whereas in the distal end of the collagen tube, no regenerated axon was found. These results suggest that the collagen filaments guide axons of the rat's sciatic nerve to regenerate for 30 mm and act as a scaffold for axonal regeneration. Thirty‐millimeter nerve regeneration of a 1‐mm‐diameter rat sciatic nerve by an artificial nerve guarantees a clinical application of the implant which should be very important for patients and surgeons. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 467–474, 2003
Structure and properties of the precipitates formed from condensed solutions of the revised simulated body fluid
Authors: Dorozhkina Elena I. , Dorozhkin Sergey V. 
Published: October 2003

AbstractPrecipitation experiments with aqueous solutions of the Kokubo's revised simulated body fluid (rSBF) equal to 2, 4, 8, and 12 times the ionic concentration of human blood plasma were performed. Instead of Hepes, solution pH was adjusted to the desired value of 7.40 ± 0.02 by either bubbling of CO2 or addition of HCl. The experiments were performed in tightly closed plastic vessels kept at 37.0 ± 0.2°C for 72 h under permanent shaking. Afterward, the suspensions were filtrated, and the precipitates were collected and analyzed. The results revealed that increasing the concentration of rSBF resulted in great changes in both the structure and the chemical composition of the precipitates. Phosphate substitution for carbonate (although the amounts of calcium and magnesium remained unchanged) and crystallinity decreasing were the most important modifications found in the precipitates formed from the highly condensed solutions of rSBF. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 578–581, 2003
In vitro cytotoxicity evaluation of a 50.8% NiTi single crystal
Authors: Manceur Aziza , Chellat Fatiha , Merhi Yahye , Chumlyakov Yuriy , Yahia L'Hocine 
Published: October 2003

AbstractTo our knowledge, the biocompatibility of nickel–titanium (NiTi) single crystals has not been reported. Yet certain orientations of single crystals present several advantages over the polycrystalline form in terms of maximal strain, fatigue resistance, and temperature range of superelasticity. Therefore we tested the in vitro biocompatibility of 50.8% NiTi single crystals in the orientation 〈001〉 after four different heat treatments in a helium atmosphere followed by mechanical polishing. The study was performed on the material extracts after immersion of the specimens in cell culture medium (DMEM) for 7 days at 37°C. Cytotoxicity studies were performed on L‐929 mouse fibroblasts using the MTT assay. J‐774 macrophages were used to assess the potential inflammatory effect of the extracts by IL1‐β and TNF‐α dosages (sandwich ELISA method). Exposure of L‐929 to material extracts did not affect cell viability. In addition, IL1‐β and TNF‐α secretion was not stimulated after incubation with NiTi extracts compared to the negative controls. These results were predictable since atomic absorption spectroscopy did not detect nickel ions in the extracts with a resolution of 1 ppm. Within the limits of in vitro testing, our results demonstrate that the TiNi50.8% single crystals do not trigger a cytotoxic reaction. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 641–646, 2003
Direct attachment of fibronectin to tresyl chloride‐activated titanium
Authors: Hayakawa Tohru , Yoshinari Masao , Nemoto Kimiya 
Published: October 2003

AbstractThe aim of this study was to bind fibronectin directly to a titanium surface treated with tresyl chloride (2,2,2‐trifluoroethanesulfonyl chloride) for the development of a strong connection of a dental implant to subepithelial connective tissues and/or peri‐implant epithelia. Basic terminal OH groups of mirror polished titanium were allowed to react with tresyl chloride at 37°C for 2 days. The tresylated titanium disk was then immersed into a fibronectin/phosphate‐buffered saline solution for 24 h at 37°C. The activation reaction of the basic OH of titanium with tresyl chloride was confirmed by S2p, F1s, and O1s spectra using X‐ray photoelectron spectroscopy and OSO2 bonds using Fourier transform infrared reflection‐absorption spectroscopy. After the reaction of fibronectin with titanium, the X‐ray photoelectron spectroscopy revealed the remarkable effect of the activation of terminal OH groups with the tresyl chloride treatment. The N1s peak derived from the attached fibronectin still remained after 60 s of argon‐ion sputtering after tresyl chloride treatment. In contrast, the N1s peak of the specimen not treated with tresyl chloride almost disappeared after only 10 s of argon‐ion etching. Fibronectin, a well‐known cell‐adhesive protein, could easily be attached to the titanium surface by use of the tresyl chloride activation technique. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 684–688, 2003
Transforming growth factor‐β1 in a sterilized tissue derived from the pig small intestine submucosa
Authors: McDevitt Cahir A. , Wildey Gary M. , Cutrone Rochelle M. 
Published: October 2003

AbstractThe extracellular matrices of connective tissues contain growth factors such as transforming growth factor (TGF)‐β1. The possibility arises, therefore, that animal connective tissues that have been excised and rendered acellular in the sterilization, lyophilization, and other preparative processes for human use may still retain active growth factors that could contribute to the clinical efficacy of the product. We therefore analyzed 4M guanidine HCl extracts of a sterilized, acellular matrix, Oasis® Wound Matrix, for the presence of TGF‐β1 by a sandwich enzyme‐linked immunosorbent assay using the soluble type II receptor for TGF‐β to capture the growth factor, and for biological activity by testing the capacity of the extracts to inhibit 3[H]thymidine incorporation into Mv1Lu cells (mink lung epithelial cells). The enzyme‐linked immunosorbent assay determined that TGF‐β1 was present at a concentration of 710.9 ± 157.7 pg/g dry weight of tissue in Oasis® and 768.1 ± 182.1 pg/g dry weight of tissue in SIS (porcine small intestinal submucosa), the disinfected precursor of Oasis®. The growth inhibition assays demonstrated that the Oasis® extracts inhibited the proliferation of Mv1Lu cells in culture, consistent with the TGF‐β1 in the material having biological activity. Most of the TGF‐β1 survives the sterilization and lyophilization processes in the preparation of the Oasis® Wound Matrix, and is functional in its ability to bind to its receptor and, apparently, in its capacity to inhibit growth. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 637–640, 2003
Localized corrosion of 316L stainless steel with SiO2‐CaO films obtained by means of sol–gel treatment
Authors: Vallet‐Regí M. , Izquierdo‐Barba I. , Gil F. J. 
Published: October 2003

AbstractSol–gel films on austenitic stainless steel (AISI 316L) polished wafer were prepared from sono‐sols obtained from tetraethylorthosilane and hydrated calcium nitrate. However, pitting was observed in different places on the stainless steel surfaces. The corrosion resistance was evaluated by the polarization resistance in simulated body fluid environment at 37°C. The critical current density, the passive current density, the corrosion potential, and the critical pitting potential were studied. The austenitic stainless steel 316L treated presents important electrochemical corrosion and consequently its application as endosseous implants is not possible. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 674–678, 2003
How to build an adapted and bioactive cell microenvironment? A chemical interaction study of the structure of Ca‐alginate matrices and their repercussion on confined cells
Authors: Bienaimé Christophe , Barbotin Jean‐Noël , Nava‐Saucedo José‐Edmundo 
Published: October 2003

AbstractAlginates are increasingly being used as medical materials (matrices for tissue regeneration, surgical sponges, hemostatic bandages, microbial and cell encapsulation, artificial bacterial biofilms, etc.). The constitution of alginate gel networks is a complex phenomenon. A great number of different kinds of polysaccharidic frameworks can come to existence depending on the conditions used for their attainment. For instance, the degree of heterogeneity and porosity of Ca‐alginate beads rely on this molecular organization. The formation of structural irregularities (superficial crust, cavities, shafts, dense or light gel frameworks, ordered or chaotic domains, etc.) within the alginate gel beads are inherent to this skeletal design. Several specific staining molecules (e.g. calcon carboxylic acid, murexide, methylene blue) that are negatively or positively charged interact with the gel network. These molecules allowed us to reveal a great variety of chemical interactions shown by the pattern coloration of the internal structure of the gel. The results observed are very different for the several matrices analyzed, which could explain to a great extent the singular behavior that cells confined in these kind of matrices exhibit. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 376–388, 2003