bluuebunny/crossref_metadata_2025 huggingface dataset:
Three‐dimensional culture of human osteoblastic cells in chitosan sponges: The effect of the degree of acetylation
Authors: Amaral I.F. , Sampaio P. , Barbosa M.A.
Published: November 2005

In this investigation, the effect of the degree of acetylation (DA) of chitosan on the behavior of human osteoblastic MG‐63 cells cultured in three‐dimensional chitosan matrices was assessed. Chitosan sponges with DAs in the range of 4 to 49% were prepared and characterized in terms of microstructure, porosity, and pore size. Collagen sponges were used as 3D control. Cell proliferation was determined using the MTT assay while the retention of the osteoblastic phenotype was monitored by assaying alkaline phosphatase activity. Cell morphology, cytoskeletal organization, and viability were assessed using different microscopy techniques. Chitosan sponges showed a similar microstructure regardless the DA, except for the highest DA used, where a more heterogeneous pore distribution was observed. In terms of cell proliferation, alkaline phosphatase activity and cell viability, cells cultured in chitosan scaffolds performed as well as in the 3D control regardless the DA, except for the highest DA used, where an inhibitory effect on cell proliferation was found. However, while in sponges with DAs ≤ 13% cells attached and spread displaying long cell filopodia and numerous cell‐to‐cell contacts, in sponges with higher DAs cells tended to remain spherical and grow into spheroid‐like cellular aggregates. In the present study, the DA played a key role in determining the affinity of osteoblastic cells towards the substrates, possibly by influencing the nature of the initial adsorbed protein layer. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Cellular response to phase‐separated blends of tyrosine‐derived polycarbonates
Authors: Bailey LeeAnn O. , Becker Matthew L. , Stephens Jean S. , Gallant Nathan D. , Mahoney Christine M. , Washburn Newell R. , Rege Aarti , Kohn Joachim , Amis Eric J.
Published: November 2005

Two‐dimensional thin films consisting of homopolymer and discrete compositional blends of tyrosine‐derived polycarbonates were prepared and characterized in an effort to elucidate the nature of different cell responses that were measured in vitro. The structurally similar blends were found to phase separate after annealing with domain sizes dependent on the overall composition. The thin polymer films were characterized with the use of atomic force microscopy (AFM), water contact angles, and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) and significant changes in roughness were measured following the annealing process. Genetic expression profiles of interleukin‐1β and fibronectin in MC3T3‐E1 osteoblasts and RAW 264.7 murine macrophages were measured at several time points, demonstrating the time and composition‐dependent nature of the cell responses. Real‐time reverse transcriptase polymerase chain reaction (RT‐PCR) depicted upregulation of the fibronectin gene copy numbers in each of the blends relative to the homopolymers. Moreover, the interleukin‐1β expression profile was found to be compositionally dependent. The data suggest strongly that optimal composition and processing conditions can significantly affect the acute inflammatory and extracellular matrix production responses. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
In vitro enzymatic stability of dendritic peptides
Authors: Yang Hu , Lopina Stephanie T.
Published: November 2005

PEGylated polyamidoamine (PAMAM) dendrimers as drug carriers have been a topic of interest because of their biomedically favorable features, including minimal toxicity, reduced immunogenicity, and excellent solubility in aqueous and most organic solutions. A PEG shell on dendrimer surface may provide steric hindrance, known as stealth properties of PEG, to stabilize drug molecules to be delivered. In this article, the effects of PEG and coupling sequence of drug, PEG, and dendrimer in modulating the stability of delivered drug molecules were evaluated. N‐succinyl‐Ala‐Ala‐Pro‐Phe‐p‐nitroanilide was chosen as a model peptide. Dendritic peptides, that is, peptide‐dendrimer, peptide‐PAMAM‐PEG, and peptide‐PEG‐dendrimer, were constructed based on Starburst™ G3.0 PAMAM dendrimer and characterized by 1H‐NMR spectroscopy. Hydrolysis of dendritic peptides was catalyzed by α‐chymotrypsin in pH 7.4 PBS buffer containing 5% DMF (v/v) at room temperature. The enzymatic stability of dendritic peptides was peptide‐PAMAM‐PEG > peptide‐PAMAM > free peptide > peptide‐PEG‐PAMAM. The ratio of PEG/peptide could be reduced for increasing peptide loading while maintaining the delivered peptides' relatively high enzymatic stability. The quantitative analysis of dendritic peptide/enzyme interactions provided the understandings of the molecular structure/stability relationships of dendrimer/drug for the design of an optimal PEGylated dendrimer‐based drug‐delivery system. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Guided tissue regeneration for using a chitosan membrane: An experimental study in rats
Authors: Kuo Shyh Ming , Chang Shwu Jen , Chen Ta Wei , Kuan Tang Ching
Published: November 2005

Barrier membranes are employed clinically to deflect the growth of gingival tissues away from root surface. They provide an isolated space over the regions with the defective tissues that allow the relatively slow growing periodontal ligament fibroblasts to be repopulated onto the root surface. Several makes of bioabsorbable membranes are now commercially available. In this study, we have employed chitosan as barrier membrane material and evaluated it for a guided tissue regeneration application. Three types of chitosan membranes: Chi‐NaOH, Chi‐Na5P3O10, and Chi‐Na2SO3(each was gelated by NaOH, crosslinked by Na5P3O10 and Na2SO3, respectively), were prepared to be evaluated by the following categories: the mechanical strength to create an effective space, the rapid rate to reach hydrolytic equilibrium in phosphate‐buffered solution, and the ease of clinical manipulative operations. Consequently, standardized, transosseous and critical sized skull defects were made in adult rats and the defective regions were covered with the specifically prepared chitosan membranes. After 4 weeks of recovering, varying degrees of bone healing were observed beneath the chitosan membranes in comparison to the control group. The chitosan covered regions showed a clear boundary space between connective tissues and bony tissues. Apparently, this process resulted in a good cell occlusion and beneficial osteogensis effect to the bone. As for the control group, the bone defect was filled with connective tissue, and a destruction of the integrity of newly formed bone was observed. Among the chitosan membranes tested in this study, Chi‐NaOH membrane provided a higher percentage of new bone formation than those from the Chi‐Na5P3O10 and Chi‐Na2SO3 families. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
New physically and chemically crosslinked hyaluronate (HA)‐based hydrogels for cartilage repair
Authors: Huin‐Amargier Cécile , Marchal Philippe , Payan Elisabeth , Netter Patrick , Dellacherie Edith
Published: November 2005

When dissolved in aqueous solutions, sodium hyaluronate substituted with low amounts of alkyl chains [amphiphilic hyaluronate (HA)] can give rise to hydrogels thanks to intermolecular reversible hydrophobic interactions, leading to a three‐dimensional (3D) network. Such hydrogels possess shear‐thinning properties and can thus be injected in cartilage defect to promote chondrocyte proliferation and cartilage repair. However, these hydrogels are only physically crosslinked and can progressively loose their 3D structure when they are in contact with aqueous fluids. To overcome this drawback, HA derivatives substituted with dodecyl chains were chemically crosslinked by a difunctional reagent, tetraethylene glycol ditosylate (TEG‐diOTs). To preserve the shear‐thinning properties of amphiphilic HA, small amounts of TEG‐diOTs were used so as to obtain a low chemical crosslinking ratio. After optimization of the synthesis parameters, aqueous solutions of the HA derivatives, crosslinked both physically and chemically, were obtained, with rheological properties improved compared to the amphiphilic polymers. As the hydrogels are aimed to cartilage repair, they were sterilized by wet heating; the effect of this treatment on the polymer characteristics was analyzed by different techniques. A similar study was carried out on HA derivatives stored under conditions mimicking physiological ones. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Electrolytic deposition of calcium phosphate/chitosan coating on titanium alloy: Growth kinetics and influence of current density, acetic acid, and chitosan
Authors: Wang Jiawei , van Apeldoorn Aart , de Groot Klaas
Published: November 2005

Electrolytically deposited calcium phosphate/chitosan coating demonstrated good bone marrow stromal cell attachment. The aim of this study was to understand the coating's growth kinetics as well as the effects of current density, acetic acid, and chitosan on the coating's formation. The scanning electron micrographs found that calcium phosphate crystals homogeneously distributed into chitosan aggregates as early as 30 min. X‐ray diffraction patterns and Fourier transform infrared spectra demonstrated that the coating experienced a compositional conversion from octacalcium phosphate to carbonate apatite during the deposition process. Electric current influenced the deposition. Higher current density accelerated the process and induced faster and more chitosan deposition. Both acetic acid and chitosan were found to inhibit calcium phosphate deposition. Chitosan was thought to induce stronger effects than acetic acid did. Furthermore, the inhibitive effect related to their concentration in the electrolyte. When chitosan concentration increased to a certain degree, this inhibitive effect not only affected calcium phosphate deposition, but also affected its own deposition. The chitosan content within the hybrid coating was small, which could be verified through Raman spectrum. At the same time, no clear evidence of chemical reactions could be found between these two components. We considered that both components were just naturally wrapped to form as a whole. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Adsorption of charged albumin subdomains on a graphite surface
Authors: Raffaini Giuseppina , Ganazzoli Fabio
Published: November 2005

We report some new molecular dynamics simulation results about the adsorption on a hydrophobic graphite surface of two albumin subdomains, each formed by three different α‐helices, considering the correctly charged side groups at pH = 7 instead of the neutral ones as done in our previous exploratory paper (Raffaini and Ganazzoli, Langmuir 2003;19:3403–3412). We find that the presence of charges affects somewhat the initial adsorption stage on the electrostatically neutral surface, but not the final one. Thus, we recover the result that a monolayer of aminoacids is eventually formed, with a rough parallelism of distant strands to optimize both the intramolecular and the surface interactions. This feature is consistent with the adsorption on the hydrophobic surface being driven by dispersion forces only, and with the “soft” nature of albumin. Additional optimizations of the final monolayer carried out at pH = 3 and 11 do not modify appreciably this picture, suggesting that adsorption on graphite is basically independent of pH. The enhanced hydration of the final adsorption state due to the (delocalized) charges of the side groups is also discussed in comparison with similar results of the neutralized subdomains. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Effects of Runx2 genetic engineering and in vitro maturation of tissue‐engineered constructs on the repair of critical size bone defects
Authors: Byers Benjamin A. , Guldberg Robert E. , Hutmacher Dietmar W. , García Andrés J.
Published: November 2005

Genetic and tissue engineering strategies are being pursued to address the clinical limitations of current bone grafting materials. Based on our previous work demonstrating that overexpression of the Runx2 osteoblastic transcription factor and in vitro construct maturation synergistically enhanced in vivo mineralization in an ectopic site (Byers et al., Tissue Eng 2004;10:1757–1766), we examined the effects of these two parameters on the repair of critical size bone defects. Primary rat bone marrow stromal cells transduced with Runx2 or control (no Runx2 insert) retroviral vector were seeded onto 3D fused deposition‐modeled polycaprolactone scaffolds. Runx2‐modified cells produced biologically‐equivalent mineralized matrices at nearly 2‐fold higher rates than control cells. Constructs cultured in vitro for 1 day (immature) or 21 days (mineralized) were subsequently implanted into critical size calvaria defects in syngeneic rats, and bone healing was analyzed by micro‐CT and histomorphometry at 28 days. Runx2‐modified and control constructs precultured for 1 day healed to a greater extent than defects receiving no implant. Cell‐free scaffolds yielded equivalent levels of bone formation as constructs precultured for 1 day. Interestingly, defects treated with control cell‐seeded constructs precultured for 21 days exhibited low bone formation compared to other construct treatments, and repair was comparable to empty defects. In contrast, Runx2‐modified constructs precultured for 21 days contained twice as much bone as control constructs precultured for 21 days and equivalent levels of new bone as cell‐free and 1 day precultured constructs. These results demonstrate interplay between Runx2 genetically‐modified cells and in vitro construct maturation in bone healing responses. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Detection of biofilm formation in Staphylococcus epidermidis from implant infections. Comparison of a PCR‐method that recognizes the presence of ica genes with two classic phenotypic methods
Authors: Arciola Carla Renata , Campoccia Davide , Baldassarri Lucilla , Donati Maria Elena , Pirini Valter , Gamberini Simonetta , Montanaro Lucio
Published: November 2005

Biofilm‐forming ability is increasingly being recognized as an important virulence factor in Staphylococcus epidermidis. This study compares three different techniques for the detection of biofilm‐positive strains. The presence of icaA and icaD genes responsible for biofilm synthesis was investigated by a PCR method in a collection of 80 S. epidermidis strains isolated from orthopedic implant infections. The results from molecular analysis were compared with those obtained by two classic phenotypic methods, the Congo red agar (CRA) plate test and the microtiter plate test (MtP). Fifty‐seven percent of all the examined strains were found icaA/icaD‐positive, of which only three were not positive for CRA test. Differently, by the MtP method, 66% of the strains were found to be biofilm‐producers but only a limited agreement with the PCR‐method was noticeable because of the observation of (icaA/icaD+)/MtP− strains (8%) and of a surprising ambiguous result of (icaA/icaD−)/MtP+ strains (16%). The category of the weak biofilm‐producers provided the highest contribution to these mismatching results (10%). The better agreement between the CRA plate test with the molecular detection of ica genes indicates the former as a reliable test for the phenotypic characterization of virulence of clinical isolates. However, MtP method remains a precious tool for the in vitro screening of different biomaterials for the adhesive properties using a reference strain. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Characterization and bioactivity of tape‐cast and sintered TCP sheets
Authors: Tanimoto Yasuhiro , Hayakawa Tohru , Sakae Toshiro , Nemoto Kimiya
Published: November 2005

The purpose of this study was to investigate the influence of sintering temperature on in vivo and in vitro bioactivities of sintered tricalcium phosphate (TCP) sheets prepared by the tape casting technique. Green sheets of β‐TCP prepared by tape casting were sintered for 2 h in a furnace at atmospheric pressure, at five different sintering temperatures: 900, 1000, 1100, 1150, and 1200°C. Measurement of X‐ray diffraction and Fourier transform infrared spectrometry showed the presence of α‐tricalcium phosphate phase in the TCP sheet sintered at 1200°C, in addition to β‐TCP phase. As compared with the other sintered TCP sheet, the TCP sheet sintered at 1200°C demonstrated a lower dissolution rate in phosphate buffered saline solution at 37°C and pH 7.4 over 24 weeks, and more amount of apatite formation in Hanks' balanced salt solution with pH 7.4 was observed. After 4 weeks' implantation of sintered TCP sheets into tibial diaphyses of rabbits, the bone‐sheet contact of the TCP sheet sintered at 1200°C was significantly higher than that of the TCP sheet sintered at 900°C. These results indicate that a flat sintered TCP sheet prepared by tape casting is a promising material for a bone substitute. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Retrieval analysis of clinical explanted vena cava filters
Authors: Gatti A. M. , Montanari S.
Published: November 2005

Vena cava filters are the most commonly used mechanical devices to prevent pulmonary embolism. A retrievable permanent filter has been available since 1999. That has allowed the direct study of thrombi captured in humans and the punctual interaction of blood and device at long and short term. Through traditional histologic methods, captured thrombi and the tissues formed around the filter were observed. An innovative environmental scanning electron microscopy technique allowed detection of micro‐ and nanosized foreign bodies inside thrombi and tissues, and chemical analysis could be carried out by means of energy dispersive spectroscopy. All specimens contained different quantities of foreign debris ranging from few tens of microns to 50 nanometers; their chemistry was not homogeneous when patients were compared, and also differed considerably within the same filter. The constant presence of debris deeply embedded in all thrombi observed may mean that they are the cause that triggered the formation of those thrombi as a result of the interaction between foreign bodies and blood components. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Design and delivery of silver sulfadiazine from alginate microspheres‐impregnated collagen scaffold
Authors: Shanmugasundaram N. , Sundaraseelan J. , Uma S. , Selvaraj D. , Babu Mary
Published: November 2005

A reconstituted collagen scaffold impregnated with silver sulfadiazine (SSD) loaded alginate microspheres, capable of delivering the drug in a controlled manner has been developed. SSD‐loaded alginate microspheres were prepared by modified water‐in‐oil emulsion technique through interfacial ionic gelation of alginate using CaCl2. The SSD‐loaded microspheres were impregnated in pepsin‐solubilized collagen, in situ, while inducing fibrillation and cast as thin scaffold. Morphological features of microspheres and microsphere‐impregnated collagen were analyzed through SEM. Distribution homogeneity of impregnated microspheres, their in vitro behavior in (Dulbecco's modified minimal essential media) DMEM, and antibacterial efficiency against ATCC pathogens were determined. Initial drug load of 20% (w/w) with respect to alginate and 40% (v/v) of 2% alginate with respect to oil phase were found to produce microspheres of optimum drug entrapment (3%) and required size range (300–370 μm). In vitro drug release studies from the scaffold showed an initial burst release of 47.5% and a controlled release for 72 h with equilibrium concentration of 68.8%. SSD‐loaded microspheres exhibited minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) levels of 32 and 40.2 μg/mL to both K. pneumoniae and E. coli respectively. P. aeruginosa showed MIC and MBC levels of 44.8 and 51.2 μg/mL respectively, while Staphylococcus aureus exhibited MIC and MBC at the same concentration range (57.6 μg/mL). The collagen‐based scaffold impregnated with SSD‐loaded alginate microspheres can deliver SSD in a controlled fashion, can control infection for extended time period with lesser dressing frequencies, and will enable easier assessment of wound. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Gelatin‐based biomimetic tissue adhesive. Potential for retinal reattachment
Authors: Chen Tianhong , Janjua Rabeea , McDermott Martin K. , Bernstein Steven L. , Steidl Scott M. , Payne Gregory F.
Published: November 2005

An adhesive that cures under moist/wet conditions could facilitate surgical procedures for retinal reattachment. We are investigating an adhesive that mimics the factor XIIIa‐mediated crosslinking of fibrin that occurs in the late stages of the blood coagulation cascade. Specifically, we use gelatin as the structural protein (in place of fibrin), and crosslink gelatin using a calcium‐independent microbial transglutaminase (in place of the calcium‐dependent transglutaminase factor XIIIa). Injection of gelatin and microbial transglutaminase (mTG) into the vitreous cavity of Sprague Dawley white rats did not elicit structural or cellular damage to the retina as evidenced from histological evaluation 2 weeks post‐injection. Qualitative in vitro studies indicate that the gelatin–mTG adhesive binds to bovine retinal tissue under wet conditions. Quantitative lap‐shear tests were performed with more robust bovine tissue from the choroid and sclera. The lap‐shear strength of the biomimetic gelatin–mTG adhesive was independent of tissue‐type and ranged from 15 to 45 kPa, which is comparable to the values reported for other soft‐tissue adhesives. These studies suggest that the mTG‐crosslinked gelatin may provide a simple, safe, and effective adhesive for ophthalmic applications. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Microstructure and corrosion behavior of porous coatings on titanium alloy by vacuum‐brazed method
Authors: Lee T.M. , Chang E. , Yen C.H.
Published: November 2005

The microstructural evolution and electrochemical characteristics of brazed porous‐coated Ti‐6Al‐4V alloy were analyzed and compared with respect to the conventionally 1300°C sintering method. The titanium filler metal of low‐melting‐point (934°C) Ti‐15Cu‐15Ni was used to braze commercially pure (CP) titanium beads onto the substrate of Ti‐6Al‐4V alloy at 970°C for 2 and 8 h. Optical microscopy, scanning and transmission electron microscopy, and X‐ray diffractometry (XRD) were used to characterize the microstructure and phase of the brazed metal; also, the potentiostat was used for corrosion study. Experimental results indicate that the bead/substrate contact interface of the 970°C brazed specimens show larger contact area and higher radius curvature in comparison with 1300°C sintering method. The microstructure of brazed specimens shows the Widmanstätten structure in the brazed zone and equiaxed α plus intergranular β in the Ti‐6Al‐4V substrate. The intermetallic Ti2Ni phase existing in the prior filler metal diminishes, while the Ti2Cu phase can be identified for the substrate at 970 for 2 h, but the latter phase decrease with time. In Hank's solution at 37°C, the corrosion rates of the 1300°C sintering and the 970°C brazed samples are similar at corrosion potential (Ecorr) in potentiodynamic test, and the value of Ecorr for the brazed sample is noble to the sintering samples. The current densities of the brazed specimens do not exceed 100 μA/cm2 at 3.5 V (SCE). These results suggest that the vacuum‐brazed method exhibits the potentiality to manufacture the porous‐coated specimens for biomedical application. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
The biocompatibility of silk fibroin films containing sulfonated silk fibroin
Authors: Ma Xilan , Cao Chuanbao , Zhu Hesun
Published: November 2005

Sulfonation reaction may be an effective method for preparation of heparin‐like materials. However, no sulfonated polymer based on protein backbone was used for improving the blood compatibility of biomaterials. In this study, the biocompatibility of new kind of composite materials films obtained by blending silk fibroin (SF) with sulfonated silk fibroin (SSF) was evaluated. The anticoagulant activity was characterized with prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT), which all increased remarkably, the clot times exceeded the measurement limit of clot detection instrument. Its platelet adhesion was also investigated as another parameter of blood compatibility. The cell compatibility of composite films was evaluated through cell morphologies on the films and cell viability by methyl thiazolyl tetrazolium (MTT) assay. Tensile strength and elongation at break of the composite films reached to 44.6 MPa and 50.3%, respectively. All these results indicated that SF/SSF composite film was a potential material for blood‐contact materials and tissue engineering matrix. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
An in vitro optimized injectable calcium phosphate cement for augmenting screw fixation in osteopenic goats
Authors: Leung Kwok Sui , Siu Wing Sum , Li Siu Fai , Qin Ling , Cheung Wing Hoi , Tam Kam Fai , Lui Pauline Po Yee
Published: November 2005

This study reports the proportioning and standardized mixing procedures for preparing a hydroxylapatite cement (tetracalcium phosphate and dicalcium phosphate) of desired viscosity and mechanical strength reproducibly for application in trauma surgery. The behavior and the biomechanical properties of the resulting bone cement in screw augmentation were then evaluated in our osteopenic goat model. The use of a shaker standardized the mixing procedure. The optimal volume of Na2HPO4 used to prepare the injectable cement was 0.45 mL/g, with averaged in vitro compressive strength of 48.29 ± 5.62 MPa. Histology showed increasing tightly‐coupled bone apposition on the cement surface without fibrous encapsulation as observed in the screw‐only controls with time in the osteopenic goat model. The cement increased the initial screw pull‐out force (54.7%, p = 0.005) significantly and the energy required to failure (54.7%, p < 0.05) significantly, and remained higher than the screw‐only controls after 3 months (9.8% and 20.2%, respectively) and 6 months (20.2% and 44.7%, respectively). These results imply potential in the prevention of interfacial micromotions and subsequent fibrous tissue formation at the implant–bone interface resulting in a decreased risk of implant failure. The optimized cement in this study may serve as a good candidate for augmenting fixation of osteoporotic bone. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Fatigue debonding of the roughened stem–cement interface: Effects of surface roughness and stem heating conditions
Authors: Damron Leatha A. , Kim Do‐Gyoon , Mann Kenneth A.
Published: November 2005

The aim of this study was to determine the effects of cyclic loading on the debond process of a roughened stem–cement interface used in total hip arthroplasty. The specific goals were to assess the effects of two surgeon‐controlled variables (stem heating and degree of stem surface roughness) and to determine if an independent finite element‐based fracture mechanics model could be used to predict the debond response. A clamped cantilever beam geometry was used to determine the fatigue debond response of the stem–cement interface and was created using an experimental mold that simulated in vivo cementing conditions. A second experiment was performed using a torsion‐loading model representative of the stem–cement–bone composite. For both experiments, two stem heating (room temperature and 50°C) and surface roughness conditions (grit blasted: Ra = 2.3 and 5.1 μm) were used. Finally, a finite element model of the torsion experiment with provision for crack growth was developed and compared with the experimental results. Results from both experiments revealed that neither stem preheating nor use of a stem with a greater surface roughness had a marked effect on the fatigue debond response. There was substantial variability in the debond response for all cases; this may be due to microscopic gaps at the interface for all interface conditions. The debond rate from the finite element simulation (10−7.31 m/cycle) had a magnitude similar to the experimental torsion model (10−(6.77 ± 1.25) m/cycle). This suggests that within the context of the experimental conditions studied here that the debond response could be assessed using a linear elastic fracture mechanics‐type approach. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Types of superregular matrices and the number ofn‐arcs and completen‐arcs in PG (r, q)
Authors: Kéri Gerzson
Published: November 2005

Based on the classification of superregular matrices, the numbers of non‐equivalentn‐arcs and completen‐arcs in PG(r,q) are determined (i) for 4 ≤ q ≤ 19, 2 ≤ r ≤ q − 2 and arbitraryn, (ii) for 23 ≤ q ≤ 32,r = 2 andn ≥ q − 8<$>. The equivalence classes over both PGL (k,q) and PΓL(k,q) are considered throughout the examinations and computations. For the classification, ann‐arc is represented by the systematic generator matrix of the corresponding MDS code, without the identity matrix part of it. A rectangular matrix like this is superregular, i.e., it has only non‐singular square submatrices. Four types of superregular matrices are studied and the non‐equivalent superregular matrices of different types are stored in databases. Some particular results ont(r,q) andm′(r,q)—the smallest and the second largest size for complete arcs in PG(r,q)—are also reported, stating thatm′(2, 31) = 22,m′(2, 32) = 24,t(3, 23) = 10, andm′(3, 23) = 16. © 2006 Wiley Periodicals, Inc. J Combin Designs 14: 363–390, 2006
Erratum to: On perfect nonlinear functions
Authors: Xiyong Zhang , Wenbao Han , Shuqin Fan
Published: November 2005

The original article to which this Erratum refers was published in Journal of Combinatorial Designs 13: 349–362, 2005.

No Abstract.
Role of the RANKL/RANK system in the induction of interleukin‐8 (IL‐8) in B chronic lymphocytic leukemia (B‐CLL) cells
Authors: Secchiero Paola , Corallini Federica , Barbarotto Elisa , Melloni Elisabetta , di Iasio Maria Grazia , Tiribelli Mario , Zauli Giorgio
Published: November 2005

B chronic lymphocytic leukemia (B‐CLL) cells express several members of the tumor necrosis factor (TNF) family, such as CD40L, CD30L, and TRAIL. By using the cDNA microarray technology, B‐CLL samples were found to overexpress receptor activator of nuclear factor kB (NF‐kB) ligand (RANKL), as compared to normal CD19+ B cells. These findings were validated at the protein level by Western blot and flow cytometry analyses. Moreover, unlike primary normal B cells, leukemic B‐CLL cells showed surface expression of RANK, the cognate transmembrane receptor of RANKL. When added in vitro to B‐CLL cultures, either alone or in association with chlorambucil or fludarabine, recombinant RANKL did not significantly modulate cell viability, and it minimally affected the IL‐8 expression/release. On the other hand, treatment with RANK‐Fc chimera potently upregulated the release of IL‐8 in the B‐CLL culture supernatants, suggesting involvement of reverse signaling through transmembrane RANKL in IL‐8 induction. In turn, exposure of B‐CLL cells to recombinant IL‐8 significantly decreased spontaneous apoptosis as well as chlorambucil‐ and fludarabine‐mediated cytoxicity in B‐CLL cells. Since IL‐8 has been implicated in progression of B‐CLL disease, our findings suggest that, by upregulating IL‐8, the RANKL/RANK system may contribute to the pathogenesis of B‐CLL. J. Cell. Physiol. 207: 158–164, 2006. © 2005 Wiley‐Liss, Inc.
Scar myofibroblasts of the infarcted rat heart express natriuretic peptides
Authors: Calderone Angelino , Bel‐Hadj Samar , Drapeau Jessica , El‐Helou Viviane , Gosselin Hugues , Clement Robert , Villeneuve Louis
Published: November 2005

The present study examined whether natriuretic peptide expression in the scar of post‐myocardial infarcted (MI) rats was derived at least in part by residing myofibroblasts. ANP and BNP mRNA levels were significantly increased in the non‐infarcted left ventricle and scar of 1‐week post‐MI male rats, as compared to the left ventricle of normal rats. The infarct region contained myofibroblasts and contracted cardiac myocytes residing predominantly in the epicardial border zone. In primary passage scar‐derived myofibroblasts, α‐myosin heavy chain mRNA was undetectable, whereas ANP, BNP, as well as adrenomedullin and corin mRNA expression persisted. In 1–3 day cultured primary passage myofibroblasts, prepro‐ANP, mature ANP, and BNP staining was observed in the cytoplasm/perinuclear region co‐incident with unorganized α‐smooth muscle actin. Following 4–7 days in culture, myofibroblasts expressed organized α‐smooth muscle actin filaments. However, natriuretic peptides were predominantly detected in the nucleus and cytoplasm, and thin filaments occupying the perinuclear region were positive for prepro‐ANP and BNP. Isoproterenol treatment of first passage scar myofibroblasts increased protein synthesis and induced BNP mRNA expression, whereas ANP mRNA levels remained unchanged. By contrast, neither ANP nor BNP mRNAs were induced following exposure to AII despite increased protein synthesis. These data highlight the novel observation that scar myofibroblasts synthesized ANP, BNP, adrenomedullin, and expressed the pro‐convertase corin. Constitutive and sympathetic‐driven natriuretic peptide synthesis by myofibroblasts may in part influence reparative fibrosis. J. Cell. Physiol. 207: 165–173, 2006. © 2005 Wiley‐Liss, Inc.
Steering estrogen signals from the plasma membrane to the nucleus: Two sides of the coin
Authors: Manavathi Bramanandam , Kumar Rakesh
Published: November 2005

Estrogen mediate its biological effects through its association with estrogen receptors (ERs). They also regulate the expression of a variety of genes involved in distinct physiological processes, including development, metabolism, and reproduction. In addition, emerging data suggest that the estrogen–estrogen receptor complex can also function as a cytoplasmic signaling molecule and may influence processes such as cardiovascular protection, bone preservation, neuroprotection, and proliferation of various cell types. Such extranuclear or nongenomic signaling pathways are rapid and supposedly independent of transcription. A recent exciting finding was that G‐coupled membrane protein receptor, GPR30, an alternative to the classical ERs, is also involved in the rapid signaling of estrogen through its direct association with estrogen. These new findings combined with the recent advances in the cytoplasmic functions of proline, glutamic acid, luecine rich protein 1 (PELP1), and metastatic tumor antigen 1 short form (MTA1s) have opened a new spectrum and raised several new concerns in the field of estrogen biology and put the attention to unveil many unknown mechanistic actions of estrogen in cellular physiology. In this review, we briefly summarize what is currently known of the cellular mechanisms and physiology of estrogen's nongenomic actions in various cellular systems used by ERs. © 2005 Wiley‐Liss, Inc.
Platelet‐derived growth factor‐BB‐induced hypertrophy of peritubular smooth muscle cells is mediated by activation of p38 MAP‐kinase and of Rho‐kinase
Authors: Romano Francesca , Chiarenza Claudia , Palombi Fioretta , Filippini Antonio , Padula Fabrizio , Ziparo Elio , De Cesaris Paola
Published: November 2005

Peritubular smooth muscle cells (PSMC) from rat testis in primary serum‐free cultures unexpectedly undergo contraction and subsequent cell hypertrophy in response to the growth factor PDGF‐BB, remaining stationary. The present study investigates the transduction pathways involved in the observed paradoxical upregulation of the differentiated phenotype and induction of hypertrophy in PSMC. PI3K, ERK, JNK, and p38 kinases, known to mediate PDGF‐BB signaling in the canonic dedifferentiative and proliferative response of smooth muscle cells (SMC) were rapidly activated by PDGF‐BB but only p38 remained activated after 2‐day stimulation. Immunofluorescence and immunoblotting experiments showed that in 4‐day treatment: (i) continuous inhibition of PI3K, of ERK, of JNK, failed to inhibit either cell enlargement and formation of prominent α‐SM actin containing stress fibers or the typical increase in α‐SM actin; (ii) when stimulated in the presence of the p38 inhibitor SB203580 both responses were significantly inhibited and cytofluorimetric analysis of cell size showed a remarkable reduction of the hypertrophic response. PDGF‐BB was also found to activate the small GTPase RhoA and inhibition of Rho‐dependent kinase ROCK by Y27632 counteracted the effects of PDGF‐BB similarly to SB203580. Both the transcription factor ATF2 and the nucleosomal kinase MSK1, downstream targets of p38, were activated by PDGF‐BB, but p38 inhibitor SB203580 inhibited only the phosphorylation of MSK1 which appeared unaffected by ROCK inhibitor Y27632. In concluding, p38 and the Rho‐ROCK system were found to play prominent, probably independent roles in the upregulation of PSMC differentiated phenotype and induction of hypertrophy by PDGF‐BB. J. Cell. Physiol. 207: 123–131, 2006. © 2005 Wiley‐Liss, Inc.
Seroreactivity to A‐type retrovirus proteins in a subset of cats with hyperthyroidism
Authors: Sander David M. , Wolfsheimer Karen , Gallaher William R. , Fermin Cesar D. , Haislip Allyson M. , Garry Robert F.
Published: November 2005

The thyroid gland is afflicted in several endocrine, autoimmune, and malignant diseases. Previous studies detected immunoreactivity against proteins of a human intracisternal A‐type retroviral particle type‐I (HIAP‐I) in serum samples from the majority of patients with Graves' disease, an autoimmune disease of the thyroid that can also affect other organs, most prominently the eyes. To determine whether hyperthyroid animals might provide a model for the retroviral involvement in thyroid autoimmunity, serum samples from 32 cats (21 hyperthyroid and 11 controls) and 10 hypothyroid dogs were examined for immunoreactivity with HIAP‐I using a Western blot technique. Of the 21 hyperthyroid cats 15 (71.4%) were HIAP‐I positive, while only 2 of 11 (11.8%) control animals without endocrine pathology were positive. No significant correlations were seen between HIAP seroreactivity and serum thyroid hormone levels (T3 and T4), age, gender, treatment history, vaccination status, or weight. No seroreactivity to HIAP‐I was detected in hypothyroid dogs. An examination of HIAP‐I reactivity in feline leukemia virus (FeLV)‐seroconverting cats found that 7/9 (78%) animals viremic for FeLV‐A showed an alteration in HIAP serology, whereas only 1/7 (14%) nonviremic animals showed a change in HIAP‐I serology. These results suggest that it may be possible to develop an animal (feline) model for the role of retroviruses in thyroid autoimmune diseases. Microsc. Res. Tech. 68:235–238, 2005. © 2005 Wiley‐Liss, Inc.
γ‐Herpesvirus neoplasia: A growing role for COX‐2
Authors: Shelby Bryan D. , Nelson Anne , Morris Cindy
Published: November 2005

Both human γ‐herpesviruses, Epstein‐Barr virus (EBV) and Kaposi's sarcoma‐associated herpesvirus (KSHV) induce neoplasia. Burkitt's and Hodgkin's lymphomas harbor EBV sequences, while KSHV has been associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric castleman's disease (MCD). Each of these γ‐herpesvirus‐associated malignancies displays typical characteristics of neoplasia, such as angiogenesis and cell survival. One enzyme commonly overexpressed in breast, prostate, and colon cancers is cyclooxygenase‐2 (COX‐2). Recently, COX‐2 overexpression has been reported in herpesvirus infections in vitro. This review will outline potential mechanisms by which COX‐2 may participate in herpesvirus‐induced neoplasia. Microsc. Res. Tech. 68:120–129, 2005. © 2005 Wiley‐Liss, Inc.
AIDS‐related non‐Hodgkin's lymphomas
Authors: Krause John
Published: November 2005

This work reviews the current status of non‐Hodgkin's lymphoma (NHL) in HIV infected patients. HIV infection remains at significantly increased risk for the development of NHL. The great majority of these lymphomas are high‐grade monoclonal B‐cell neoplasms often occurring in unusual sites. A number of genetic abnormalities have been found but additional studies are necessary to understand the etiology and pathogenesis of NHL in the setting of HIV infection. The cases in this paper have been seen on the Hematopathology service of the Tulane Health Sciences Center. Microsc. Res. Tech. 68:168–175, 2005. © 2005 Wiley‐Liss, Inc.
The human T‐cell leukemia virus type 1 (HTLV‐1): New insights into the clinical aspects and molecular pathogenesis of adult t‐cell leukemia/lymphoma (ATLL) and tropical spastic paraparesis/HTLV‐associated myelopathy (TSP/HAM)
Authors: Shuh Maureen , Beilke Mark
Published: November 2005

Human T‐cell leukemia virus type 1 (HTLV‐1) was the first human retrovirus to be identified in the early 1980s. The isolation and identification of a related virus, HTLV‐2, and the distantly related human immunodeficiency virus (HIV) immediately followed. Of the three retroviruses, two are associated definitively with specific diseases, HIV, with acquired immune deficiency syndrome (AIDS) and HTLV‐1, with adult T‐cell leukemia/lymphoma (ATLL) and tropical spastic paraparesis/HTLV‐1–associated myelopathy (TSP/HAM). While an estimated 10–20 million people worldwide are infected with HTLV‐I, infection is endemic in the Caribbean, parts of Africa, southwestern Japan, and Italy. Approximately 4% of HTLV‐I infected individuals develop ATLL, a disease with a poor prognosis. The clinical manifestations of infection and the current biology of HTLV viruses with emphasis on HTLV‐1 are discussed in detail. The implications for improvements in diagnosis, treatment, intervention, and vaccination are included, as well as a discussion of the emergence of HTLV‐1 and ‐2 as copathogens among HIV‐1‐infected individuals. Microsc. Res. Tech. 68:176–196, 2005. © 2005 Wiley‐Liss, Inc.
Involvement of human intracisternal A‐type retroviral particles in autoimmunity
Authors: Sander David M. , Szabo Sara , Gallaher William R. , Deas Jane E. , Thompson James J. , Cao Yan , Luo‐Zhang Hong , Liu Leonita G. , Colmegna Ines , Koehler Jeffery , Espinoza Luis R. , Alexander Steve S. , Hart Darren J. , Tom Daniel M. , Fermin Cesar D. , Jaspan Jonathan J. , Kulakosky Peter C. , Tenenbaum Scott A. , Wilson Russell B. , Garry Robert F.
Published: November 2005

Prior studies have linked retroviruses to various arthropathies and autoimmune diseases. Sjögren's syndrome (SS), a systemic autoimmune disease, is characterized by aggressive infiltration of lymphocytes into the salivary and lacrimal glands, resulting in destruction of the glands and dry mouth and eyes (sicca syndrome). The infiltrating lymphocytes in SS may become overtly malignant, and thus, the incidence of lymphoma is greatly increased in SS patients. A human intracisternal A‐type retroviral particle type I (HIAP‐I) has been isolated from persons with SS. HIAP‐I shares a limited number of antigenic epitopes with human immunodeficiency virus (HIV), but is distinguishable from HIV by morphological, physical, and biochemical criteria. A substantial majority of patients with SS or systemic lupus erythematosus (SLE) have serum antibodies to the proteins of this human retrovirus. Fewer than 3% of the normal blood donor population have antibodies to any HIAP‐associated proteins. A second type of a human intracisternal A‐type retrovirus, HIAP‐II, was detected in a subset of patients with idiopathic CD4 lymphocytopenia (ICL), an AIDS‐like immunodeficiency disease. Most HIAP‐II positive ICL patients were also antinuclear antibody positive. Reviewed here are additional studies from several laboratories suggesting that HIAP or related viruses may be involved in SLE and other autoimmune conditions. Additionally, results of comprehensive surveys of autoimmune patients to determine seroreactivity to HIAP, and other human retroviruses, including HIV and human T‐lymphotropic virus type I, are reported. Microsc. Res. Tech. 68:222–234, 2005. © 2005 Wiley‐Liss, Inc.
Evaluation of the nuclear delivery and intra‐nuclear transcription of plasmid DNA condensed with µ (mu) and NLS‐µ by cytoplasmic and nuclear microinjection: a comparative study with poly‐L‐lysine
Authors: Akita Hidetaka , Tanimoto Mitsuhide , Masuda Tomoya , Kogure Kentaro , Hama Susumu , Ninomiya Keiko , Futaki Shiroh , Harashima Hideyoshi
Published: November 2005

Background

The efficient nuclear delivery of plasmid DNA (pDNA) is essential for the development of a promising non‐viral gene vector. In an attempt to achieve nuclear delivery, NLS‐mu, a novel pDNA condenser, was prepared. This consists of mu, a highly potent polypeptide for condensing the pDNA, and a SV40 T antigen‐derived nuclear localization signal (NLSSV40).

Methods

The utility of NLS‐mu was assessed in terms of green fluorescent protein (GFP) expression after cytoplasmic and nuclear microinjection of GFP‐encoding pDNA along with the transfection, and compared with mu and poly‐L‐lysine (PLL). Trans‐gene expression after cytoplasmic microinjection was affected by the efficiencies of nuclear transfer and following intra‐nuclear transcription. To evaluate the nuclear transfer process separately, we introduced a parameter, a nuclear transfer score (NT score), which was calculated as the trans‐gene expression after cytoplasmic microinjection divided by that after nuclear microinjection.

Results

As expected, the rank order of trans‐gene expression after the transfection and cytoplasmic microinjection was NLS‐mu > mu > PLL. However, the calculated NT scores were unexpectedly ranked as mu = NLS‐mu > PLL, suggesting that mu, and not NLSSV40, is responsible for the nuclear delivery of pDNA. In addition, confocal images of rhodamine‐labeled pDNA indicated that pDNA condensed with mu and NLS‐mu was delivered as a condensed form. In comparing the nuclear transcription, the rank order of trans‐gene expression after nuclear microinjection was PLL = NLS‐mu > mu, suggesting that intra‐nuclear transcription is inhibited by efficient condensation by mu, and is avoided by the attachment of NLSSV40.

Conclusions

Collectively, NLS‐mu, which consists of chimeric functions, is an excellent DNA condenser, and the process is based on mu‐derived nuclear transfer and NLSSV40‐derived efficient intra‐nuclear transcription. Copyright © 2005 John Wiley & Sons, Ltd.
(d,1)‐total labeling of graphs with a given maximum average degree
Authors: Montassier Mickaël , Raspaud André
Published: November 2005

The (d,1)‐total number $\lambda _{d}^{T}(G)$ of a graph G is the width of the smallest range of integers that suffices to label the vertices and the edges of G so that no two adjacent vertices have the same color, no two incident edges have the same color, and the distance between the color of a vertex and its incident edges is at least d. In this paper, we prove that $\lambda_{d}^{T}(G) \leq \Delta (G) + 2d - 2$ for connected graphs with a given maximum average degree. © 2005 Wiley Periodicals, Inc. J Graph Theory