bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histologic identification of polyethylene wear debris using Oil Red O stain
Authors: Schmalzried Thomas P. , Jasty Murali , Rosenberg Andrew , Harris William H. 
Published: May 2005

AbstractUltra high molecular weight polyethylene (UHMWPE) wear particles are frequently implicated in causing failure of total joint arthroplasties by eliciting a foreign body reaction. The majority of these particles are subcellular and many are submicron in size. Identification of these small particles of UHMWPE by conventional histologic techniques is difficult. We have therefore investigated the utility of Oil Red O (ORO) stain to identify UHMWPE on histologic sections.A wide variety of specimens was studied including an experimental rabbit model with subcutaneous implantation of polyethylene particles as well as specimens from clinical cases with joint arthroplasties. The sensitivity and specificity of ORO stain was compared to conventional polarized light microscopy for the identification of particulate UHMWPE debris. The ORO stain was found to be as sensitive in identifying particulate UHMWPE debris as polarized light microscopy. However, ORO stain was less specific: two specimens that did not contain any UHMWPE also stained with ORO. Careful examination of standard hematoxylin and eosin stained sections with polarized light was therefore more specific for the identification of particulate UHMWPE. As a single test, the ORO stain does not appear to offer any clear advantage specifically for the identification of UHMWPE. © 1993 John Wiley & Sons, Inc.
A comparison between 51chromium release and LDH release to measure cell membrane integrity: Interest for cytocompatibility studies with biomaterials
Authors: Bordenave Laurence , Bareille Reine , Lefebvre Françoise , Baquey Charles 
Published: May 2005

AbstractA variety of methods have been recorded for the assessment of altered cellular functions caused by biomaterials. Cell membrane integrity can be determined by different tests depending upon the cell membrane permeability to various markers. To measure the degree of cell damage, we have chosen to compare the release of two markers in the supernatants: enzyme lactate dehydrogenase (LDH, which we wanted to compare to that of radioactive chromium preincorporated in cells, the latter being validated by a standard), from three cell types: cells from a fibroblastic cell line (3T3 Balb/c) and human differentiated endothelial cells and osteoblasts, exposed to injurious agents and to biomaterials of classical use. The labeling procedure as well as the incubation periods performed, were carried out according to a standard. Celllabeling efficiency ranged from 4 to 10%. The biomaterials tested provoked no or slight cell membrane damage. After linear regression analysis, we found high coefficients between chromium release and LDH release.Thus, the determination of LDH activity, which is easy to manipulate, could be a satisfactory test to evaluate cell membrane integrity in contact with biomaterials and a prerequisite stage before the more sophisticated 51chromium release test. © 1993 John Wiley & Sons, Inc.
Effect of hydroxyapatite coating on bone growth into porous titanium alloy implants under loaded conditions
Authors: Oonishi Hironobu , Noda Tomohiro , Ito Seiichi , Kohda Akira , Ishimaru Hiroshi , Yamamoto Mitsumasa , Tsuji Eiji 
Published: May 2005

AbstractTitanium alloy tibial segmented defect repair devices whose stems were coated with two layers of titanium alloy beads (Ti‐6A1‐4V, bead diameter c. 750 μm) were implanted in six beagle dogs. In four of the animals stems had been plasma‐sprayed with hydroxyapatite (HA); the other two animals received devices with uncoated stems. Devices intended for 6‐month and 3‐month evaluation were implanted in right and left tibiae, respectively. Because the amount of bone ingrowth into pore spaces was greater in cortical bone than in cancellous bone, stems were more stable and firmer in the cortical bone. In stems coated with HA, new bone tissue came into contact with the surface of beads in the superficial layer of the stem faster than in stems not so coated. Furthermore, new bone tissue entered into pore spaces in these stems earlier, in larger amounts, and reached more deeply, binding directly to the beads. Rate and quality of bone ingrowth did not differ between the 3‐month and 6‐month tibiae; in other words, optimal bone ingrowth was attained within 3 months postimplantation. © 1994 John Wiley & Sons, Inc.
Behaviour of endothelial cells cultured in the presence of polymers impregnated with adsorbable proteins
Authors: Cenni Elisabetta , Ciapetti Gabriela , Arciola Carla Renata , Di Leo Alessandro , Falsone Giuseppina , Pizzoferrato Arturo 
Published: May 2005

AbstractThe aim of this study is the in vitro evaluation of the functional modifications of human endothelial cells in the presence of Dacron® impregnated with resorbable proteins. For this purpose, human endothelial cells isolated from the umbilical vein have been put in contact for 48 h with knitted Dacron® impregnated with collagen or gelatin and with nonimpregnated knitted Dacron® and double velour Dacron®. As control, endothelial cells cultured in the absence of material were used. After the contact time, cell counts were performed. In addition, the concentrations of two proteins synthesized by endothelium, tissue plasminogen activator (t‐PA) and plasminogen activator inhibitor 1 (PAI‐1), were evaluated on the supernatants. In the cultures in contact with Dacron® impregnated with collagen or gelatin and in those in contact with knitted Dacron®, we have observed a smaller cell growth than that observed in cultures without materials. The synthesis of t‐PA showed some significant variations between the control cultures and those in contact with the materials. PAI‐1 production was significantly reduced in the cultures in contact with gelatin impregnated Dacron® and with knitted Dacron®. Double velour Dacron® caused no significant variation in any of the examined parameters. © 1994 John Wiley & Sons, Inc.
FEM analysis of stress and deformation in the vicinities of arterial graft anastomosis
Authors: Matsumoto Takeo , Itagaki Hiroyuki , Hayashi Kozaburo 
Published: May 2005

AbstractEffects of compliance mismatch at end‐to‐end artery/graft anastomoses on the distributions of wall stresses and compliance were studied using the finite element method. The canine common carotid artery (CCA), and expanded polytetrafluoro‐ethylene (EPTFE) thin‐walled graft, and a newly developed polyurethane graft (HS‐2) were used as the models for the host artery, stiff graft, and compliant graft, respectively. Mechanical properties of CCA and HS‐2 were determined from a pressure–diameter test, those of EPTFE graft were obtained by tensile test. Nonlinear elasticity of CCA and HS‐2 was incorporated by iterating a linear FEM analysis: elastic moduli of the vessel walls were changed every 5 mmHg. The results showed that, in the case of the artery/EPTFE anastomosis in which the diameters of the artery and the graft were matched at 0 mmHg, regions of high tensile and shear stresses appeared in the graft near the anastomosis at the intraluminal pressure of 100 mmHg. The stress concentrations were remarkable, even if the diameters were matched at 100 mmHg and the pressure was varied within a physiological range (60–140 mmHg). Moreover, a hypercompliant zone appeared in the arterial wall near the anastomosis in this case. On the other hand, neither high stress concentrations nor hypercompliant zone appeared near the artery/HS‐2 anastomosis. Because the mechanical complications at the compliance‐mismatched anastomosis might finally result in graft failure and occlusion, it is important to match the compliance of graft to that of natural arteries, particularly to improve the patency of small‐calibered arterial grafts. © 1994 John Wiley & Sons, Inc.
Surface modification of polymeric biomaterials by albumin grafting using γ‐irradiation
Authors: Kamath Kalpana R. , Park Kinam 
Published: May 2005

AbstractPolymeric biomaterial surfaces were modified by albumin grafting to improve their blood compatibility. Albumin molecules were functionalized by introducing double bonds using glycidyl acrylate. The functionalized albumin was covalently attached to various biomaterial surfaces such as polypropylene, polycarbonate, and poly(vinyl chloride) by γ‐irradiation. Surface‐induced platelet adhesion and thrombus formation on the albumin‐grafted surfaces was examined using computer‐enhanced video microscopy and scanning electron microscopy. The amount of the grafted albumin was dependent on the γ‐irradiation dose and the concentration of albumin used for adsorption. The grafted albumin molecules remained on the surface even after exposure to blood for prolonged time periods. This approach was used to graft albumin to polymeric materials of an oxygenator. The albumin grafting resulted in a substantial improvement in blood compatibility as compared to control oxygenators. The covalent grafting of functionalized albumin by γ‐irradiation obviates the need for premodification of chemically inert polymer surfaces. It is useful for albumin grafting to various biomaterial surfaces. © 1994 John Wiley & Sons, Inc.
Biomaterials lubricated for minimum frictional resistance
Authors: Tomita Naohide , Tamai Susumu , Okajima Eigorou , Hirao Yoshihiko , Ikeuchi Ken , Ikada Yoshito 
Published: May 2005

AbstractTo improve the frictional characteristics of a biomaterial, the mechanical performance of a lubricated surface was studied. In vitro friction tests showed that the coefficient of dynamic friction of the lubricated surface was about 0.01 against rabbit bladder and the coefficient of static friction increased with the preload period. The efficacy of a lubricated cystoscope was evaluated by an in vivo test simulating cystoscope operation. The maximal and the total resistance force on the cystoscope model were found to decrease with the surface lubrication. Histological study revealed that urethral damage caused by rubbing with the cystoscope model was reduced by this lubrication technique. Presumably, prolonged retention of water on the lubricated surface region prevented tissue adhesion to the foreign material. © 1994 John Wiley & Sons, Inc.
Physical properties of model viscoelastic materials
Authors: Silver Frederick H. , LiBrizzi Joseph J. , Benedetto Dominick 
Published: May 2005

AbstractPrevious observations on polysaccharides used as viscoelastic agents in ophthalmic surgery suggest that the pseudoplasticity of solutions of hyaluronan (HA) and the low surface tension of hydroxypropylmethylcellulose (HPMC) solutions are physical properties that make these solutions useful clinically. Our laboratories are interested in correlating the physical properties of macromolecular solutions with the ability of these molecules to protect ocular structures during eye surgery. The purpose of this study is to compare the physical properties of model viscoelastics with the properties of HA and HPMC. The results of these studies suggest that polysaccharides that form extended structures in solution at low shear rates and that are characterized by large decreases in the axial ratio at high shear rates, exhibit pseudoplastic behavior. In this study pseudoplasticity is exhibited by polysaccharides with molecular weights in excess of 450 000, and is insensitive to the backbone chemistry for linear macromolecules. In addition, low surface tension is associated with charged macromolecules that have a high positive second virial coefficient. © 1994 John Wiley & Sons, Inc.
Effects of hydroxyapatite and alumina sheaths on postoperative peritendinous adhesions in chickens
Authors: Siddiqi Najam A. , Hamada Yoshiki , Ide Takatoshi , Akamatsu Noriya 
Published: May 2005

AbstractTwo experimental methods for restoring flexor tendon sheath integrity and preventing adhesions around traumatized flexor tendons utilizing artificial tendon sheaths made of either hydroxyapatite (HAp) or alumina were studied in a flexor tendon‐trauma model and compared to a standard tendon sheath repair and a control. Eighty toes were divided equally into a control group, a sheath repair group, an HAp group, and an alumina group. Profundus tendons in zone II were divided and repaired after sublimis excision in all groups. In the sheath repair group, the flexor sheath was also repaired after suturing the tendon. In artificial sheath groups, sheaths made of HAp and alumina were placed over the repair sites to protect them from the surrounding tissues. In the control group, after repairing the tendon, the flexor sheath was excised and no artificial sheaths were used. Each toe was immobilized in a plaster cast for 3 weeks. After three weeks, the plaster cast was removed followed by the removal of the sheaths in the artificial sheath groups through a small incision in the skin in zone II. Active mobilization was encouraged in each group. Postoperative adhesions were examined at 3, 6, 9, and 12 week intervals by using light microscopic techniques. To further explore the effects of artificial sheaths on tendon healing, transmission electron microscopy was done for the HAp and alumina groups at 3, 6, and 12 week intervals. Results demonstrated decreased severity of postoperative adhesions in the HAp as well as in the alumina groups in comparison with the sheath repair and controls. A space resembling the fibro‐osseous canal was formed around the tendon after removing the sheaths. This space remained patent until 12 weeks, 9 weeks after removing the sheaths, and a newly formed tendon sheath‐like structure lined by synovial cells and with a peritenon‐like structure over the tendon surface was observed. In the sheath repair and control groups, the severity of adhesions was decreased with the passage of time, to some extent due to unrestricted mobility. However, a newly formed tendon sheath or peritenon‐like structure was not observed. Electron microscopic studies confirmed good healing at the suture in the HAp and alumina groups with no evidence of necrosis. These results are qualitative in nature as no statistical tests were performed. From these results we conclude that if the tendon is separated from the surrounding granulation tissue by a barrier with good biocompatibility, the tendon can heal with fewer adhesions. Artificial sheaths may be used to reduce adhesions in severe injuries of the hand where postoperative immobilization is necessary due to fractures, vascular, or nerve injuries. © 1995 John Wiley & Sons, Inc.
Influence of fluoride on titanium in an acidic environment measured by polarization resistance technique
Authors: Boere Gert 
Published: May 2005

AbstractThe effect of sodium fluoride on the polarization resistance of titanium was investigated. Titanium plates were exposed to sodium chloride solutions with increasing fluoride concentrations. This was done at pH 7 and 4 at 37°C. The polarization resistance technique was chosen because it is the only electrochemical corrosion test procedure that allows sequential measurements of the same specimen and provides a quantitative basis to estimate corrosion currents unlike measurements of the potential. The results showed a large decrease in polarization resistance with increasing fluoride concentration at pH 4. The polarization resistance at pH 7 remained constant after a slight decrease at a very high value, even with a high fluoride concentration. The results clearly confirm that titanium is attacked by fluoride in an acidic environment. The clinical implications are that fluoride rinses or fluoride gels must have a neutral pH if there is a titanium containing device in the oral environment despite the less prophylactic effectiveness. © 1995 John Wiley & Sons, Inc.
Controlling osteopontin orientation on surfaces to modulate endothelial cell adhesion
Authors: Liu Lingyun , Chen Shengfu , Giachelli Cecilia M. , Ratner Buddy D. , Jiang Shaoyi 
Published: May 2005

AbstractOsteopontin (OPN) is an important extracellular matrix protein that has been shown to impact wound healing, inflammation, and the foreign body reaction, and has been identified as a potential surface component for engineered biomaterials. OPN contains the arginine‐glycine‐aspartic acid (RGD) moiety that has been shown to mediate cell adhesion through interactions with integrins. In its preferred orientation and conformation on a surface, the functional domains of OPN will be presented to cells to the greatest extent. However, control of protein orientation and conformation is still challenging. In this work, we investigated OPN adsorption and cell adhesion to the OPN layer on self‐assembled monolayers (SAMs) of alkanethiols terminated with various functional groups and on a gold surface. The four SAM terminal groups studied were CH3, OH, NH2, and COOH, representing hydrophobic, hydrophilic but neutral, positively charged, and negatively charged surfaces, respectively. Surface plasmon resonance biosensor and atomic force microscopy were used to characterize the adsorption of OPN on these surfaces. An in vitro cell adhesion assay of bovine aortic endothelial cells was performed to test the functionality of OPN on various SAMs. Surface plasmon resonance results showed that the amount of protein adsorbed on the NH2 surface is close to a monolayer and similar to that on the COOH surface, consistent with the atomic force microscopy results. However, based on cell adhesion experiments, both cell count and average cell spreading area on the NH2 surface are much higher than those on the COOH surface. From these results, it is suggested that the orientation and conformation of OPN on a positively charged NH2 surface is more favorable for cell adhesion and spreading than on a negatively charged COOH surface. The surface coverage of bovine aortic endothelial cells on the surfaces studied decreased in the following order: NH2 > Au > CH3 > COOH > OH whereas the mean cell spreading area decreased in the following order: NH2 > Au > CH3 > COOH. Our studies show that surface properties will alter OPN behavior on surfaces, thus influencing cell interactions. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Evaluation of polymer scaffolds to be used in a composite injectable system for intervertebral disc tissue engineering
Authors: Brown R. Quinn , Mount Andrew , Burg Karen J. L. 
Published: May 2005

AbstractAdult porcine nucleus pulposus cells were seeded onto gelatin, demineralized bone matrix (DBM), and polylactide scaffolds and cultured in vitro. Cellular behavior in response to the scaffolds was analyzed using biochemical assays, histology, and real‐time quantitative reverse transcriptase‐polymerase chain reaction. Scanning electron microscopy showed pronounced differences in surface texture of the scaffolds. Nucleus pulposus cells attached and assumed an elongated fibroblast‐like morphology on the gelatin and DBM scaffolds. The cells cultured on the gelatin and DBM were metabolically active and expressed types I and II collagen and aggrecan. Detached cellular aggregates with a rounded morphology were noted in the culture tubes containing the polylactide scaffolds. Both surface chemistry and texture likely had a role in causing differences in cellular behavior in response to scaffold material. Promising results were observed using the gelatin and demineralized bone scaffolds, but the behavior of cells cultured on these scaffolds will need to be characterized further. This initial research will be used to direct future work involved in developing this composite injectable tissue engineering system. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Fidelity of micropatterned cell cultures
Authors: Endler Elizabeth E. , Nealey Paul F. , Yin John 
Published: May 2005

AbstractMethods that enable the culture of micropatterned cells may help advance our fundamental understanding of cell–cell and cell–surface interactions, while facilitating the development and implementation of cell‐based biological assays. However, the long‐term stability of the cell patterns can limit the time scales over which such methods can be informative. Here we used self‐assembling monolayers (SAMs) to localize the adsorption of baby hamster kidney (BHK‐21) cells as well as cells from a murine astrocytoma‐derived cell line (delayed brain tumor) in linear arrays. We tested the effects of surface chemistries, fibronectin pre‐treatments, array dimensions, and cell types on pattern fidelity. Changes in patterns were monitored by phase‐contrast microscopy up to 96 h post‐plating, followed by digital imaging, and these changes were quantified by measuring an “intrusion distance” or the average distance cells extend beyond the initial adhesive/non‐adhesive boundary. Loss of pattern boundaries involved different mechanisms for different cells. Treatment of patterned surfaces with fibronectin prior to plating of cells tended to promote earlier loss of pattern fidelity, and the extent of pattern loss was further augmented for SAMs formed using hydrophobic monolayers. Finally, reduction of gap spacing between adjacent cell arrays promoted pattern loss. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
In vivo identification of the interaction site of ErbB2 extracellular domain with its autoinhibitor
Authors: Hu Pinliang , Feng Jiannan , Zhou Tao , Wang Jianing , Jing Baofeng , Yu Ming , Hu Meiru , Zhang Xuemin , Shen Beifen , Guo Ning 
Published: May 2005

AbstractDirect interference with the transforming potential of ErbB2 has become a subject of great interest. Disruption of critical ErbB2 ectodomain interactions may lead to novel therapeutic approaches for the treatment of various tumors. The ErbB receptor signaling can be inhibited by rationally designed peptide mimetics based on the subdomains of ErbB ectodomain. The mimetics can bind to the ErbB receptor specifically and block inter‐receptor interactions, resulting in the growth inhibition of ErbB2‐overexpressing cells in vitro. In this study, three‐dimensional structure of herstatin, an autoinhibitor of ErbB2 and ErbB2 ectodomain complex was constructed by computer‐aided molecular modeling. The binding site on ErbB2 ectodomain for herstatin was determined at S1 domain. The mutants of ErbB2 ectodomain were constructed. The interactions of ErbB2 ectodomain and its mutants with herstatin were analyzed for the first time in living cells that coexpressed herstatin and ErbB2 ectodomain or the mutants. The S1 domain in ErbB2 ectodomain was verified as the interaction site with herstatin by immunoprecipitation, confocal microscopy, and fluorescence resonance energy transfer (FRET). The binding region of herstatin on ErbB2 ectodomain might be a potential target region for the drug design. © 2005 Wiley‐Liss, Inc.
Bcl‐2 overexpression in melanoma cells increases tumor progression‐associated properties and in vivo tumor growth
Authors: Trisciuoglio Daniela , Desideri Marianna , Ciuffreda Ludovica , Mottolese Marcella , Ribatti Domenico , Vacca Angelo , Del Rosso Mario , Marcocci Lucia , Zupi Gabriella , Del Bufalo Donatella 
Published: May 2005

AbstractIn this study, we demonstrated that bcl‐2 overexpression in human melanoma cells consistently enhanced the activity of multiple metastasis‐related proteinases, in vitro cell invasion, and in vivo tumor growth. In particular, by using the M14 parental cell line, the MN8 control clone, and two bcl‐2 overexpressing derivatives, we found that bcl‐2 overexpressing cells exposed to hypoxia, when compared to parental cells, expressed higher level of several metalloproteases (MMPs) such as MMP‐2, MMP‐7, MT1‐MMP, and tissue inhibitors of metalloproteases‐1 and ‐2. Moreover, bcl‐2 overexpression in melanoma cells enhanced in vitro invasion on matrigel and, in vivo tumor growth. The more aggressive behavior of bcl‐2 transfectants tumors is significantly associated to an increase in MMP‐2 expression as well as in a more elevated microvessel density as compared to the parental line. Taken together, our data suggest that bcl‐2 plays a pivotal role in the regulation of molecules associated with the migratory and invasive phenotype, contributing, in cooperation to hypoxia, to tumor progression. © 2005 Wiley‐Liss, Inc.