bluuebunny/crossref_metadata_2025 huggingface dataset:
Cervical metastases in upper aerodigestive tract squamous cell carcinoma: Histopathologic analysis and reporting
Authors: Jose Jemy , Coatesworth Andrew P. , MacLennan Ken
Published: February 2003

Background.

Accurate histopathologic assessment of neck dissections is of paramount importance. Retrospective analyses of the distribution of lymph node metastases have formed the rationale for elective neck dissection. However, standard techniques for examination of neck dissection specimens may have difficulty in correctly recognizing node levels and may also miss micrometastases, microscopic extracapsular spread, and soft tissue deposits.

Methods.

Two hundred thirty‐seven neck dissections were performed in 173 patients with squamous cell carcinoma of the upper aerodigestive tract between August 1995 and November 2000. The neck dissections were separated into node levels peroperatively, sectioned at 6μm thickness, and stained with hematoxylin and eosin.

Results.

Eleven thousand three hundred forty‐nine lymph nodes were identified and examined. The mean yield per neck dissection was 50.4 (range, 12–131); 21.4% had extracapsular spread, 11.0% had soft tissue deposits, and 13.3% had both. A third of the metastatic nodes were 3 mm or less in diameter.

Conclusions.

The accurate pathologic staging of the neck in patients with upper aerodigestive tract squamous cell cancer is important for providing prognostic information and optimizing the treatment plan for the patient. Accurate staging also allows the changing patterns of disease to be monitored and allows equitable comparison of patients in clinical trials and among surgical units. © 2003 Wiley Periodicals, Inc. Head Neck 25: 194–197, 2003
Generation of vaccine‐primed lymphocytes for the treatment of head and neck cancer
Authors: Chang Alfred E. , Li Qiao , Jiang Guihua , Teknos Theodoros N. , Chepeha Douglas B. , Bradford Carol R.
Published: February 2003

Background.

This study was performed to assess the ability of autologous tumor vaccines to induce T‐cell reactivity to squamous cell cancers (SCC).

Methods.

Irradiated autologous tumor cells admixed with bacillus Calmette‐Guérin (BCG) were given intradermally in patients with advanced head and neck cancers. Vaccine‐primed lymph node (VPLN) cells were secondarily activated with anti‐CD3 mAb and expanded in IL‐2 for adoptive immunotherapy. A mean (± SEM) of 2 (±0.6) × 1010 anti‐CD3–activated cells were administered in conjunction with IL‐2 in six patients.

Results.

Anti‐CD3–activated VPLN cells secreted IFN‐γ and GM‐CSF in response to autologous tumor cells but not to allogeneic tumor cells in four of five patients analyzed. Both CD4+ and CD8+ tumor reactive cells were present in the VPLN. There were no significant tumor responses after transfer of the anti‐CD3–activated VPLN. In separate experiments, costimulation of VPLN cells with anti‐CD3 and anti‐CD28 mAb resulted in enhanced cytokine secretion to autologous tumor compared with anti‐CD3 activation alone.

Conclusions.

Both CD4+ and CD8+ responses can be induced to SCC by autologous tumor vaccination. However, additional approaches need to be identified to enhance the therapeutic efficacy of this approach. © 2003 Wiley Periodicals, Inc. Head Neck 25: 198–209, 2003
Intraoperative radiotherapy for head and neck and skull base cancer
Authors: Pinheiro A. Daniel , Foote Robert L. , McCaffrey Thomas V. , Kasperbauer Jan L. , Bonner James A. , Olsen Kerry D. , Cha Stephen S. , Sargent Daniel J.
Published: February 2003

Background.

The purpose of this study was to evaluate the use of intraoperative electron beam radiotherapy (IORT) as an adjuvant modality in the treatment of advanced head and neck and skull base cancer.

Methods.

Between 1991 and 1996, 34 patients with squamous cell carcinoma (SCCA) and 10 patients with non‐SCCA were enrolled in this prospective nonrandomized clinical trial. Most patients had been previously treated with combinations of surgery, external beam radiotherapy, and chemotherapy. The most frequent sites treated were the skull base (56%) and the neck (44%). IORT was delivered in a dedicated operating room suite with energies of 6 to 15 MeV (6 MeV most commonly used) at doses of 12.5 to 22.5 Gy.

Results.

At 2 years overall and disease‐free survival was 32% and 21%, respectively, for the SCCA patients and 50% and 40%, respectively, for the non‐SCCA patients. Tumor control rates at 2 years in the IORT field were 46% for the SCCA patients and 52% for the non‐SCCA patients. For squamous cell histology, survival in patients with microscopic residual tumor did not differ from those with no residual tumor, but they both had significantly longer disease‐free survival than those patients with gross residual at the time of IORT (p= .03), with a trend toward longer overall survival (p= .09). The only complication directly attributable to IORT was a neuropathy in a patient who received an IORT dose of 22.5 Gy (cumulative dose 130.1 Gy).

Conclusions.

IORT at a dose of 12.5 Gy is safe and produces tumor control and survival for patients likely to have microscopic residual disease in sites difficult to resect such as the skull base. © 2003 Wiley Periodicals, Inc. Head Neck 25: 217–226, 2003
Differentially expressed genes associated with CIS‐diamminedichloroplatinum (II) resistance in head and neck cancer using differential display and CDNA microarray
Authors: Higuchi Eisaku , Oridate Nobuhiko , Furuta Yasushi , Suzuki Seigo , Hatakeyama Hiromitsu , Sawa Hirofumi , Sunayashiki‐Kusuzaki Kousaku , Yamazaki Ken‐ichi , Inuyama Yukio , Fukuda Satoshi
Published: February 2003

Background.

The mechanism by which cancer cells become resistant to cis‐Diamminedichloroplatinum (II) (cDDP) is not completely understood. To investigate the molecular markers involved in the cDDP resistance, we compared the gene expression profiles between a head and neck squamous cell carcinoma (HNSCC) line sensitive to cDDP and its cDDP‐resistant variant.

Methods.

Both a fluorescent differential display and a cDNA microarray analysis were applied to distinguish the gene profiles between KB, a human HNSCC line, and its cDDP‐resistant variant (KB/cDDP). These results were confirmed by Northern blot analysis.

Results.

One up‐regulated gene, glycoprotein hormone α‐subunit, and two down‐regulated genes coding membrane proteins, human folate receptor and tumor‐associated antigen L6, were identified in KB/cDDP cells.

Conclusions.

Our findings suggest that development of the cDDP‐resistant phenotype is accompanied by alternations of gene expression including a glycoprotein hormone and membrane proteins. These gene products could be new molecular markers for resistance to cDDP. © 2003 Wiley Periodicals, Inc. Head Neck 25: 187–193, 2003
Detection of recurrent nasopharyngeal carcinomas with thallium‐201 single‐photon emission computed tomography in patients with indeterminate magnetic resonance imaging findings after radiotherapy
Authors: Tai Chih‐Jaan , Liang Ji‐An , Yang Shih‐Neng , Tsai Ming‐Hsui , Lin Cheng‐Chieh , Kao Chia‐Hung
Published: February 2003

Background.

The aim of this study was to evaluate the usefulness of thallium‐201 (Tl‐201) single‐photon emission CT (SPECT) to detect recurrent nasopharyngeal carcinomas (NPC) when MRI findings are indeterminate.

Methods.

After radiotherapy, 26 NPC patients with indeterminate MRI findings were included in this study. MRI, Tl‐201, and biopsy were performed at least 4 months after radiotherapy and within 1 week. The final results were based on histopathologic findings and clinical follow‐up after at least 6 months.

Results.

For detecting recurrent NPC in indeterminate MRI findings, the sensitivity, specificity, and accuracy of Tl‐201 SPECT were 92.3%, 92.3%, and 92.3%, respectively.

Conclusions.

On the basis of this result, Tl‐201 SPECT seems to be effective in detecting recurrent NPC when MRI findings are indeterminate. © 2003 Wiley Periodicals, Inc. Head Neck 25: 227–231, 2003
Progressive edge detection compression for fingerprint images
Authors: Al‐Asmari Awad K.
Published: February 2003

In this article, a progressive fingerprint image compression (for storage or transmission) that uses an edge detection scheme is developed. First, the image is decomposed into two components: the primary component, which contains the edges, and the secondary component, which contains the textures and the features. Then, a general grasp for the image is reconstructed in the first stage at bit rates of 0.0223 and 0.0245 bpp for the tested fingerprints images (samples 1 and 2), respectively. The quality of the reconstructed images is competitive with the 0.75‐bpp target bit set by the FBI standard. Also, the compression ratio and the image quality of this algorithm are competitive with other methods reported in the literature. The compression ratio for our algorithm is about 45:1 (0.180 bpp). © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 211–216, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10025
Application of Krylov subspaces to SPECT imaging
Authors: Calvini P. , Bertero M.
Published: February 2003

The application of the conjugate gradient (CG) algorithm to the problem of data reconstruction in SPECT imaging indicates that most of the useful information is already contained in Krylov subspaces of small dimension, ranging from 9 (two‐dimensional case) to 15 (three‐dimensional case). On this basis, a new, proposed approach can be basically summarized as follows: construction of a basis spanning a Krylov subspace of suitable dimension and projection of the projector–backprojector matrix (a 106 × 106 matrix in the three‐dimensional case) onto such a subspace. In this way, one is led to a problem of low dimensionality, for which regularized solutions can be easily and quickly obtained. The required SPECT activity map is expanded as a linear combination of the basis elements spanning the Krylov subspace and the regularization acts by modifying the coefficients of such an expansion. By means of a suitable graphical interface, the tuning of the regularization parameter(s) can be performed interactively on the basis of the visual inspection of one or some slices cut from a reconstruction. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 217–228, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10026
Fast color image restoration with multisensors
Authors: Ng Michael K. , Bose N. K.
Published: February 2003

In this article, we consider restoring a single‐color image from two degraded frames of the same scene by a RGB sensor and a luminance sensor. The RGB‐to‐YIQ transformation, the classical Tikhonov regularization and the Neumann boundary condition are used in the restoration process. Regularization based on generalized cross‐validation function with multisensors is also used to obtain the high‐quality restored image. The resulting method is shown to provide improved restoration over other restoration methods. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 189–197, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10028
On the fast search algorithms for vector quantization encoding
Authors: Chen Wen‐Shiung , Hsieh Lili , Yuan Shang‐Yuan
Published: February 2003

One of the major difficulties arising in vector quantization (VQ) is high encoding time complexity. Based on the well‐known partial distance search (PDS) method and a special order of codewords in VQ codebook, two simple and efficient methods are introduced in fast full search vector quantization to reduce encoding time complexity. The exploitation of the “move‐to‐front” method, which may get a smaller distortion as early as possible, combined with the PDS algorithm, is shown to improve the encoding efficiency of the PDS method. Because of the feature of energy compaction in DCT domain, search in DCT domain codebook may be further speeded up. The experimental results show that our fast algorithms may significantly reduce search time of VQ encoding. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 204–210, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10030
A nonlinear inverse problem inspired by three‐dimensional diffuse tomography: Explicit formulas
Authors: Grünbaum F. Alberto , Matusevich Laura Felicia
Published: February 2003

We use time of flight information to obtain explicit inversion formulas for a simple model of optical tomography. This can be considered as an instance of a more general nonlinear inversion problem for multi‐terminal networks. In this case the network is nonplanar with lots of cycles but the underlying physical model yields a highly structured situation. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 198–203, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10031
The role of the TH1 and TH2 immune responses in loosening and osteolysis of cemented total hip replacements
Authors: Arora Amarpal , Song Yong , Chun Linda , Huie Phil , Trindade Michael , Smith R. Lane , Goodman Stuart
Published: February 2003

The mechanisms underlying the development of osteolysis and aseptic loosening have an impact on the longevity of total hip replacements (THRs). This study examines the specific roles of lymphocytes in the TH1 and TH2 subsets in osteolysis and aseptic loosening of THR. Tissue from periprosthetic regions from patients with loose, cemented acetabular components were used to determine the TH1 and TH2 cytokine profile. Twelve tissue specimens from patients with radiographic signs of osteolysis, and nine tissue specimens from patients with no signs of osteolysis were harvested during revision surgery. Immunohistochemistry using primary antibodies against CD3, interferon (IFN)‐γ, interleukin (IL)‐2, IL‐4, and IL‐10 was performed on frozen sections to determine the percentage of positive cells for each of the sections. No statistically significant differences in the percentage of positive cells expressing cytokines characteristic of the TH1 pathway (IFN‐γ, IL‐2) or TH2 pathway (IL‐4, IL‐10) were found when comparing osteolytic and non‐osteolytic tissues. However, significant numbers of T cells (averaging about 10% of the total cells) and TH1 and TH2 immune cytokines (averaging 3–5% of cells) implicate a possible role for immune processes at the prosthetic interface. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 693–697, 2003
Transmission electron microscopic study on setting mechanism of tetracalcium phosphate/dicalcium phosphate anhydrous‐based calcium phosphate cement
Authors: Chen Wen‐Cheng , Lin Jiin‐Huey Chern , Ju Chien‐Ping
Published: February 2003

This work studied transmission electron microscopy on the setting mechanism of tetracalcium phosphate/dicalcium phosphate anhydrous (TTCP/DCPA)‐based calcium phosphate cement. The results suggest the process for early‐stage apatite formation as the follows: When TTCP and DCPA powders are mixed in the phosphate‐containing solution, the TTCP powder is quickly dissolved because of its higher solubility in the acidic solution. The dissolved calcium and phosphate ions, along with those ions readily in the solution, are then precipitated predominantly on the surface of DCPA particles. Few apatite crystals were observed on the surface of TTCP powder. During the later stages of reaction, the extensive growth of apatite crystals/whiskers, with a calcium/phosphorous ratio very close to that of hydroxyapatite, effectively linked DCPA particles together and also bridged the larger TTCP particles. It is suggested that, when the large TTCP particles are locked in place by the bridging apatite crystals/whiskers, the CPC is set and would not dissolve when immersed in Hanks' solution after 20–40 min of reaction. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 664–671, 2003
Ultra‐high molecular weight polyethylene oxidation reduces metalloproteinase 2 secretion in human osteoblast‐like cells in vitro: A mechanism of modulation of extracellular matrix
Authors: Bosetti M. , Renò F. , Bracco P. , Costa L. , Cannas M.
Published: February 2003

Ultra‐high molecular weight polyethylene (UHMWPE) sterilization with gamma rays induced high oxidation levels both on the surface and in the bulk that alter its structure and mechanical properties. The oxidation process of gamma‐radiated UHMWPE induces a reduction of molecular weight and, consequently, a less abrasive resistance that has been related, among others, to the failure of UHMWPE in vivo. To explain the role of cells in such events, human osteoblast‐like cells were seeded onto UHMWPE and oxidized UHMWPE discs. Cellular viability and morphology were evaluated along with matrix metalloproteinases (MMPs) production and activity. Oxidized UHMWPE did not induce any significant cytotoxic effects as observed by lactate dehydrogenase activity compared to the nonoxidized form; no changes in the cell morphology after 4 and 8 days proliferation were observed. In growth medium metalloproteinase 2 (gelatinase‐A, MMP‐2) was produced and released by osteoblast‐like cells. We observed that cells grown onto oxidized UHMWPE discs decreased the release and activity of MMP‐2 after 4 and 8 days culture compared to cells grown on control and non‐oxidized UHMWPE discs; metalloproteinase 9 (gelatinase‐B, MMP‐9) release was not significantly influenced. The absence of cytotoxic and morphological effects in the presence of a down‐regulation of MMP‐2 release and activity suggest that oxidized polyethylene surfaces may modulate matrix remodeling and, consequently, bone formation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 698–705, 2003
Polymeric matrices based on graft copolymers of PCL onto acrylic backbones for releasing antitumoral drugs
Authors: Abraham Gustavo A. , Gallardo Alberto , San Román Julio , Fernández‐Mayoralas Alfonso , Zurita Mercedes , Vaquero Jesús
Published: February 2003

Graft copolymers of poly(ϵ‐caprolactone) (PCL) on poly(dimethylacrylamide) (PDMAm), poly(methylmethacrylate) (PMMA), or on copolymers of poly(DMAm‐co‐MMA) have been synthesized and characterized by 1H NMR spectroscopy, differential scanning calorimetry (DSC), and size exclusion chromatography (SEC). These partially biodegradable copolymer matrices have been proposed as drug delivery systems for the release of low‐molecular‐weight glycosides. Octyl‐N‐acetyl‐6‐O‐[2,2‐bis(hydroxymethyl)‐3‐hydroxypropyl]‐α‐D‐glucosamide, a synthetic carbohydrate able to inhibit the proliferation of human malignant glioma cells in culture and transplanted glioma in rats was selected as drug model. The in vitro aqueous behavior of four drug‐loaded and unloaded graft copolymers of different MMA: DMAm and PCL ratios has been analyzed performing swelling, degradation, and drug release experiments. An intimate dependence of the aqueous behavior with the composition has been found. The higher was the DMAm content, the higher was the hydrophilicity of the synthesized systems as well as the swelling, degradation, and drug release rate. In vivo experiments in pigs demonstrated the very good tolerance of drug‐loaded implanted polymeric discs, and that >95% of the charged drug is released after 2 months' implantation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 638–647, 2003
Behavior of MG‐63 cells on nylon/chitosan‐blended membranes
Authors: Wang Jyh‐Horng , Wei Cheng‐Wey , Liu Hwa‐Chang , Young Tai‐Horng
Published: February 2003

In this work, the properties of nylon, chitosan, and their blended membranes were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and wide‐angle X‐ray diffraction analysis. The SEM photographs show that the undulating surface of the nylon membrane became less obvious by blending with chitosan. The DSC and X‐ray diffraction analysis show that constitutionally different features in the combination of two polymer chains were revealed, suggesting that nylon and chitosan are immiscible at the microscopic level in the blended membranes. Furthermore, an attempt was made to understand whether the two components contribute independently to the adhesion, growth, and activation of MG‐63 osteoblastlike cells. The cell adhesion increased with increasing chitosan content, indicating that the affinity between the cells and the membranes increased with increasing chitosan content. Although the blended membranes with higher nylon content exerted an inhibitory effect on cell adhesion, cells cultured on the nylon membrane proliferated at higher rates and the nylon membrane was the least stimulating of MG‐63 cell cytokine production over a 4‐day period when compared with all the other membranes. Combined with the result of cell growth and cell activation, the chitosan content in the blended membrane did not proportionally influence the behavior of MG‐63 cells. It is proposed that cell's size was larger than the scale of nylon or chitosan domain in the blended membranes because of the incomplete miscibility between them. Therefore, even if the composition of the blended membranes is systematically changed, every cell covers a multiphase surface that is considered a totally new material for cells. Consequently, cell growth and cell activation on a blended membrane are not simply proportional to their composition. In contrast, cell adhesion is a simpler process, like a physical adsorption process, which is related to the bulk property of a blended membrane. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 606–615, 2003
Electrochemically assisted deposition of thin calcium phosphate coatings at near‐physiological pH and temperature
Authors: Rößler S. , Sewing A. , Stölzel M. , Born R. , Scharnweber D. , Dard M. , Worch H.
Published: February 2003

An electrochemical method for the deposition of calcium phosphate phases on titanium surfaces using the galvanostatic mode is presented. Deposition was performed in a (Ca2+/HxPO4(3−x)−)‐containing electrolyte near physiological conditions with regard to pH (6.4) and temperature (36°C). Cathodic alkalization leads first to the formation of a thin homogeneous layer that shows a nanoscale surface topography of alternating wall‐like elevations and channels. It is thought that these channels in the calcium phosphate prelayer are formed as pathways for hydroxyl ions and hydrogen. Upon this layer, spheres of amorphous calcium phosphate (ACP) are formed as indicated by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy. According to transmission electron microscopy images, these spheres consist of small clusters of calcium phosphate (∼30 nm) and can grow up to 300 nm in diameter. Characteristic for this ACP is a high water content as seen by FTIR. As a function of current density, the ACP is then transformed into crystalline hydroxyapatite (HAP), which was identified using FTIR and X‐ray diffraction. The morphology of the HAP crystals can be described as needles with dimensions of <500‐nm length and <60‐nm width. By choice of different electrochemical parameters, a homogeneous coating of either ACP, HAP, or the intermediate phase can be achieved, as shown in a kinetic phase diagram, thus allowing the formation of coatings with different properties in solubility and morphology. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 655–663, 2002
Inhibition of CEM calcification by the sequential pretreatment with ethanol and EDTA
Authors: Singla Anuj , Lee Chi H.
Published: February 2003

The major object of the present study is to optimize the anticalcification activity of ethanol on bioprosthetic heart valve (BHV) calcification. We hypothesize that the chelating agent, in combination with ethanol, will synergistically prevent aortic wall calcification. Collagen‐elastin matrix (CEM) was developed as a calcifiable matrix for simulating the calcification process of implantable biomaterials. The efficacy of the combination effects of ethanol and EDTA on the calcification process of CEMs was investigated by implanting them after pretreatment with various conditions of ethanol and EDTA in the rat subdermal model. The relationship between calcium concentrations and pretreatment conditions (a series vs. simultaneous, i.e., first ethanol and then EDTA in water solution, the reverse, or EDTA in ethanol) was established and the optimal condition for prevention of BHV calcification was determined. The mechanistic studies on anticalcification effects exerted by particular pretreatment sequences were also conducted using FTIR and differential scanning calorimetry (DSC). The sequential pretreatment of CEM first with ethanol and then EDTA in water solution significantly decreased the calcification rate of CEM compared the control. The percentage of prevention of calcification by the serial treatment of ethanol (80 % v/v) and then EDTA in water solutions decreased, as the concentration of elastin in the CEM increased. The percentage of preventing calcification was 42%, 28.6%, and 22.9% for CEM containing collagen and elastin ratios of 90:10, 50:50, 20:80, respectively. These results indicate that elastin is the major regulatory component of BHV calcification, and preventive effects on calcification increased only when CEM were pretreated with first ethanol and then EDTA in water solution. Moreover, the sequential effect is more apparent in the matrix of less elastin content, which is close to the physiological range. The sequential inhibitory effects of ethanol and EDTA could occur due to the distinct separate actions of each agent, thereby achieving a relatively greater inhibition of calcification. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 706–713, 2003
Fibronectin fibrillogenesis on sulfonated polystyrene surfaces
Authors: Pernodet Nadine , Rafailovich Miriam , Sokolov Jonathan , Xu D. , Yang Nan‐Loh , McLeod Kenneth
Published: February 2003

Extracellular matrix (ECM) protein adsorption and organization serves as a critical first step in the development and organization of tissues. Advances in tissue engineering, therefore, will depend on the ability to control the rate and pattern of ECM formation. Fibronectin is a prominent component of the ECM, which undergoes fibrillogenesis in the presence of cells. Using sulfonated polysyrene surfaces, we showed that fibronectin undergoes a transition from monolayer to multilayer adsorption at calculated surface charge densities above 0.03 Coulombs (C)/m2. At charge densities above approximately 0.08 C/m2, distinct fibronectin fibrillar networks are observed to form with a fibril morphology similar to those observed to form in situ on cell surfaces. This self‐organization process is time dependent, with the fibrils achieving dimensions of 30–40 μm in length and 1 μm in height after 72 h of incubation. We suggest that the polarization of charge domains on the polyampholytic fibronectin molecules near high charge density surfaces is sufficient to initiate the multilayer adsorption and the organization of these fibrillar structures. These results suggest that the nonlinear dependence of adsorption on surface charge density may play an important role in the self‐organization of many matrix components. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 684–692, 2003
Textured hydroxyapatite interface onto biomedical titanium‐based coatings
Authors: Manso Miguel , Herrero P. , Fernández M. , Langlet M. , Martínez‐Duart J. M.
Published: February 2003

Hydroxyapatite (HAP) bioceramic coatings grown onto titanium‐nitride (TiN) buffer layers by the aerosol‐gel procedure present interfaces with a preferred growth orientation. These coatings were crystallized at 800°C and subsequently etched to ease the study of the interface by Auger electron spectroscopy depth profiling. Ion beam milling was applied to cross‐section samples to analyze the interface structures using transmission electron microscopy. At the interface, the HAP crystals showed a 〈002〉 orientation. It was shown by Auger electron spectroscopy depth profiling that O atoms diffuse into the nitride interlayer, indicating that the formation of O channels in the HAP structure is the driving force inducing the textured film. The outstanding biocompatible properties of both the materials and properties of their interface suggest that HAP/TiN structures are particularly well suited for endoprosthetic applications. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 600–605, 2003
Fibroblast growth on surface‐modified dental implants: An in vitro study
Authors: Groessner‐Schreiber Birte , Neubert Anja , Müller Wolf‐Dieter , Hopp Michael , Griepentrog Michael , Lange Klaus‐Peter
Published: February 2003

A major consideration in designing dental implants is the creation of a surface that provides strong attachment between the implant and bone, connective tissue, or epithelium. In addition, it is important to inhibit the adherence of oral bacteria on titanium surfaces exposed to the oral cavity to maintain plaque‐free implants. Previous in vitro studies have shown that titanium implant surfaces coated with titanium nitride (TiN) reduced bacterial colonization compared to other clinically used implant surfaces. The aim of the present study was to examine the support of fibroblast growth by a TiN surface that has antimicrobial characteristics. Mouse fibroblasts were cultured on smooth titanium discs that were either magnetron‐sputtered with a thin layer of titanium nitride, thermal oxidized, or modified with laser radiation (using a Nd‐YAG laser). The resulting surface topography was examined by scanning electron microscopy (SEM), and surface roughness was estimated using a two‐dimensional contact stylus profilometer. A protein assay (BCA assay) and a colorimetric assay to examine fibroblast metabolism (MTT) were used. Cellular morphology and cell spreading were analyzed using SEM and fluorescence microscopy. Fibroblasts on oxidized titanium surfaces showed a more spherical shape, whereas cells on laser‐treated titanium and on TiN appeared intimately adherent to the surface. The MTT activity and total protein were significantly increased in fibroblasts cultured on titanium surfaces coated with TiN compared to all other surface modifications tested. This study suggests that a titanium nitride coating might be suitable to support tissue growth on implant surfaces. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 591–599, 2003
Reevaluation of ethylene oxide hemolysis and irritation potential
Authors: Anand V. P. , Cogdill C. P. , Klausner K. A. , Lister L. , Barbolt T. , Page B. F. J. , Urbanski P. , Woss Casimir J. , Boyce John
Published: February 2003

The in vitro hemolytic and in vivo mucosal irritation potential of ethylene oxide (EO) was investigated with standard procedures used to determine the biocompatibility of medical devices. Test solutions containing EO at concentrations of 25, 50, 100, 250, 500, 1,250, 2,500, 5,000, or 10,000 μg/mL were prepared in saline to simulate a worst‐case aqueous extraction of standard medical devices containing 125, 250, 500, 1,250, 2,500, 6,250, 12,500, 25,000, or 50,000 μg/g of EO, respectively. Concentrations of EO up to 500 μg/mL were not hemolytic (<5% hemolysis after a 4‐h exposure), whereas ≥1250 μg/mL of EO resulted in significant hemolysis. Hamster cheek pouches exposed to cotton pellets saturated with EO at concentrations of up to 2500 μg/mL for 4 h with a recovery period of 14 days were without effects attributable to EO. However, at ≥5000 μg/mL of EO, significant histomorphological alterations of the buccal mucosa were observed and attributed to EO exposure. It was concluded that solutions of EO of up to 500 μg/mL representing an aqueous extract of a general medical device containing at least 2500 μg/g of EO residue do not result in significant hemolysis and irritation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 648–654, 2003
Juniper wood as a possible implant material
Authors: Gross K. A. , Ezerietis E.
Published: February 2003

Natural materials, such as wood and bone, possess structures fulfilling the requirements of support and transport of nutrients. Similarity in function and properties provides inspiration for investigating the possible use of wood as an implant material. Juniperus communis wood is dense, durable, and strong and has naturally impregnated essential oils that display antiseptic properties. This study investigated the toxicity of the oil, the effect of sterilization on the mechanical properties of the wood, and bone attachment with animal studies. The possible toxicity of the oil was determined orally and by intravenous injection. At low concentrations, the dose that would be released by the wood in the body could be tolerated without any detrimental effects. Sterilization of the wood in boiling water lowered the elastic modulus and modulus of rupture to a level at which the elastic modulus could be better matched to bone. Wood shaped into the form of femoral implants were implanted into rabbits and displayed good acceptance by the body up to a period of 3 years, indicating bone apposition, abutment into pores, and growth into drilled cavities. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 672–683, 2003
The effect of sintered dicalcium pyrophosphate on osteoclast metabolism: An ultrastructural study
Authors: Sun Jui‐Sheng , Huang Yi‐Chau , Lin Feng‐Huei , Chen Li‐Ting
Published: February 2003

Sintered dicalcium pyrophosphate (SDCP), a synthetic compound, has proved to be both bioabsorbable and biocompatible in vivo. Recent work in our institute also has demonstrated that the ingestion of SDCP can increase bone mass in the ovariectomized rat. In this study, we used an in vitro cell culture model to investigate the ultrastructural changes and fate of osteoclasts induced by SDCP. Quantitative evaluation of osteoblasts and osteoclasts after administration of SDCP was performed. We studied immunohistochemical and ultrastructural features of osteoclasts undergoing apoptosis. The results showed that at 10−4 M SDCP, the osteoblast cell count increased significantly, whereas the osteoclast population decreased significantly. Apoptosis of the osteoclast population was well demonstrated by immunohistochemical study. Ultrastructural study showed that the Golgi apparatus was degraded or dispersed in the cytoplasm. Later, osteoclasts revealed pyknotic nuclei showing condensation and margination of heterochromatins and DNA fragmentation, which are typical features of apoptosis. In addition, disruption of nuclear envelopes leading to leakage of nuclear contents into the cytoplasm was observed in the late stage of apoptosis. In conclusion, SDCP‐induced apoptosis of osteoclasts was characterized by ultrastructural changes of the nucleus accompanied by degradation of cellular organelles. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 616–621, 2003
Calcium phosphate coatings obtained by Nd:YAG laser cladding: Physicochemical and biologic properties
Authors: Lusquiños F. , De Carlos A. , Pou J. , Arias J. L. , Boutinguiza M. , León B. , Pérez‐Amor M. , Driessens F. C. M. , Hing K. , Gibson I. , Best S. , Bonfield W.
Published: February 2003

The plasma spray (PS) technique is the most popular method commercially in use to produce calcium phosphate (CaP) coatings to promote fixation and osteointegration of the cementless prosthesis. Nevertheless, PS has some disadvantages, such as the poor coating‐to‐substrate adhesion, low mechanical strength, and brittleness of the coating. In order to overcome the drawbacks of plasma spraying, we introduce in this work a new method to apply a CaP coating on a Ti alloy using a well‐known technique in the metallurgical field: laser surface cladding. The physicochemical characterization of the coatings has been carried out by means of X‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X‐ray analysis (EDX). The biologic properties of the coatings have been assessed in vitro with human osteoblast‐like MG‐63 cells. The overall results of this study affirm that the Nd:YAG laser cladding technique is a promising method in the biomedical field. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 630–637, 2003
Cell adhesion on supported lipid bilayers
Authors: Andersson Ann‐Sofie , Glasmästar Karin , Sutherland Duncan , Lidberg Ulf , Kasemo Bengt
Published: February 2003

The cell and protein repellent properties of supported phospholipid bilayer (SPB) membranes were investigated. The SPBs were prepared by vesicle adsorption on SiO2 surfaces. The vesicles of phosphatidylcholine fuse and rupture, and form a supported bilayer covering the surface. We carried out cell culture experiments on several surfaces, including SPBs, using two types of epithelial cells to address the cell adhesional properties. The Quartz Crystal Microbalance Dissipation (QCM‐D) technique was used to monitor the SPB formation and subsequent protein adsorption. Neither cell type adhered or proliferated on SiO2 surfaces coated with SPBs, whereas both cell types adhered and proliferated on the three control surfaces of SiO2, tissue culture glass, and TiO2. The QCM‐D measurements showed that about two orders of magnitude less mass adsorbed on a SPB surface compared to a TiO2 surface, from serum‐containing media (10% fetal bovine serum). The reduced adsorption on the SPB is a likely explanation for the nondetectable epithelial cell adhesion on the SPB surface. Biomembranes are therefore attractive candidate systems to achieve alternating cell‐resistant and cell‐interacting regions on surfaces, by including specific cell‐binding proteins in the latter regions. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 622–629, 2003
Putative role for EPC‐1/PEDF in the G0 growth arrest of human diploid fibroblasts
Authors: Pignolo Robert J. , Francis Mary Kay , Rotenberg Mitch O. , Cristofalo Vincent J.
Published: February 2003

EPC‐1/PEDF expression is closely associated with reversible growth arrest in normal human diploid fibroblast‐like (HDF) cells and is diminished with proliferative senescence in vitro. EPC‐1 expression in HDF cells is induced under conditions of density‐dependent contact inhibition and growth factor deprivation. Antiserum generated against EPC‐1 recognizes a secreted protein of approximately 50 kDa from medium conditioned by early passage HDF cells, but not from senescent cells. The addition of EPC‐1 antiserum to early population doubling level (PDL) cultures near the plateau phase of growth significantly increases the number of cells entering DNA synthesis. Affinity purified EPC‐1 antibodies alone enhance the ability of near plateau‐phase early PDL WI‐38 cells to synthesize DNA by as much as threefold. Further, the addition of recombinant EPC‐1 (rEPC‐1) to logarithmically growing cells resulted in a marked decrease in the ability of these cells to enter DNA synthesis. We also demonstrate the loss of EPC‐1 expression in WI‐38 and IMR‐90 HDF cell lines with both senescence and simian virus 40 (SV40) transformation. The loss of EPC‐1 expression with SV40 transformation occurs at the level of steady‐state mRNA and protein accumulation with genomic EPC‐1 sequences grossly intact. Taken together, these results suggest that EPC‐1 may play a role in the entry of early passage fibroblasts into a G0 state or the maintenance of such a state once reached. © 2003 Wiley‐Liss, Inc.
Inflammatory mediators and reversible myocardial dysfunction
Authors: Kan Hong , Finkel Mitchell S.
Published: February 2003

A variety of seemingly unrelated clinical conditions manifest the same effects on the heart. These effects include: (1) reversible myocardial dysfunction, (2) β‐adrenergic desensitization, and (3) activation of inflammatory mediators. We provide evidence supporting a role for cytokines, mitogen activated protein kinases (MAP kinases), and nitric oxide (NO) as common mediators of reversible myocardial dysfunction and β‐adrenergic desensitization. Data from animal models and human studies support a pathogenic role for these inflammatory mediators in ischemic as well as non‐ischemic myocardial dysfunction. It is suggested that compensatory cellular programs are activated to provide short‐term protection from brief periods of ischemia and infection. Continuous activation of these compensatory pathways leads to cardiomyopathy and chronic (congestive) heart failure. Elucidating the signaling pathways involved has the potential to provide the opportunity to exploit the cardioprotective advantages of these agents without bearing the burden of excessive stimulation. © 2003 Wiley‐Liss, Inc.
Hydrocortisone has a protective effect on CyclosporinA‐induced cardiotoxicity
Authors: Florio Salvatore , Ciarcia Roberto , Crispino Luca , Pagnini Ugo , Ruocco Antonio , Kumar Christine , D'Andrilli Giuseppina , Russo Ferdinando
Published: February 2003

CyclosporinA (CsA) is an immunosuppressive drug which induces severe adverse effects such as cardiotoxicity and nephrotoxicity. In several therapeutic protocols CsA is used in association with corticosteroids to obtain better therapeutic results. Recently, our studies showed that CsA increases blood pressure while inhibit Nitric Oxide (NO) production in vivo. In this study we evaluated in rat cardiomyocytes the effects of CsA, used alone or in association with Hydrocortisone (HY), on intracellular calcium concentration, NO production and lipid peroxidation (MDA level). Our results demonstrated that CsA increased intracellular calcium and such effect was dose‐dependent. HY used alone, slightly decreased intracellular calcium, while dramatically reduced CsA‐induced calcium fluxes. CsA (3.2 μM) increased lipid peroxidation and this effect was blunted by HY. Both CsA and HY inhibited NO production in rat cardiomyocytes acting on this pathway synergically. Our results demonstrated that in rat cardiomyocytes, CsA toxicity is due to a calcium overload, which in turn induce lipid peroxidation and determines oxidative stress‐induced cell injury. Treatment with HY effectively inhibits CsA‐induced toxicity, decreasing lipid peroxidation as well as calcium intracellular concentration. Our findings seem to suggest that glucocorticoids may be effective in reducing CsA‐induced cardiotoxicity at concentrations which are consistent with current therapeutic doses. © 2003 Wiley‐Liss, Inc.
Characterization of apoptosis signal transduction pathways in HL‐5 cardiomyocytes exposed to ischemia/reperfusion oxidative stress model
Authors: Cicconi Simona , Ventura Natascia , Pastore Donatella , Bonini Paolo , Nardo Paolo Di , Lauro Renato , Marlier Lionel N.J.L.
Published: February 2003

During ischemia/reperfusion (I/R), cardiomyocytes are exposed to sudden lack of nutrients and successively to radical oxygen species (ROS). In the present study, we used the HL‐5 cardiac atrial myocyte cell line exposed to serum/glucose depletion added or not in H2O2 to mimic ROS during ischemia, then replaced in their standard culture medium to simulate reperfusion. We investigated the effects of serum/glucose depletion combined or not to ROS exposure on AKT and MAP kinases activation to address the role of each event with respect to apoptosis. We demonstrate that serum/glucose depletion per se did not induce apoptosis when compared to ROS exposure. In particular, ROS recruited p38MAPK and JNK pathways. SB202190 preventing p38MAPK activity, partially protected HL‐5 from apoptosis while blocking JNK, thanks to JNKI, further enhanced apoptosis. Blocking phosphatidylinositol (PI) 3‐kinase with LY294002 or ERKs with U0126 was without consequence on apoptosis. Finally, BCL‐2 and BCL‐XL/S expression levels were analyzed in cells exposed to 1 h ischemia followed by 12‐h reperfusion in the presence or not of SB202190; BCL‐2, but not BCL‐XL/S, expression was decreased in ROS treated cells but SB202190 failed to restore BCL‐2 level. Our data suggest that p38MAPK activation primarily mediates ROS‐induced apoptosis while concomitant JNK activation would represent a scavenger pathway for cells trying to escape apoptosis. © 2003 Wiley‐Liss, Inc.
Control of hepatocyte DNA synthesis by intracellular pH and its role in the action of tumor promoters
Authors: Lee Chow H. , Cragoe Edward J. , Edwards Anthony M.
Published: February 2003

The mechanisms of tumor promotion in liver by various xenobiotics of diverse structure are not well understood. However, these tumor promoters share the ability to exert growth‐stimulatory effects on hepatocytes. Our laboratory has been utilizing normal rat hepatocytes under defined conditions of primary cultures, to investigate growth‐stimulatory actions of liver tumor promoters. We have shown that most, if not all, of the liver tumor promoters tested stimulate hepatocyte DNA synthesis when added in combination with epidermal growth factor (EGF), insulin, and glucocorticoids. In the present study, we sought evidence for the role of the Na+/H+ antiporter and cytoplasmic alkalinization in the direct growth‐stimulatory actions of tumor promoters on hepatocytes. Hepatocytes cultured under conditions (bicarbonate‐buffered medium) where intracellular pH (pHi) was independent of extracellular pH (pHe), EGF‐ and insulin‐stimulated rates of DNA synthesis were unaffected by modest changes in pHe. However, under conditions (HEPES‐buffered medium) where pHi varied in a linear fashion with pHe, rates of EGF‐ and insulin‐stimulated DNA synthesis were highly dependent on pHe. Similarly, 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) and α‐hexachlorocyclohexane (HCH)‐stimulated DNA synthesis were pHe‐dependent but were stimulatory over different pHe ranges, suggesting that these promoters may act by distinct mechanisms. Chemicals that are capable of inducing rapid cytoplasmic alkalinization, ammonium chloride (1 and 15 mM) and monensin (0.5 μM), were found to stimulate hepatocyte DNA synthesis. The role of the Na+/H+ antiport in controlling pHi of hepatocytes was demonstrated by artificially acidifying 2′,7′‐bis(carboxyethyl)‐5,6‐carboxyfluorescein acetoxymethyl (BCECF)‐loaded isolated hepatocytes with 20 mM sodium acetate and the use of specific inhibitors. Amiloride and its analogues inhibited pHi recovery from the acid load in a dose dependent manner and the relative potency of these inhibitors paralleled their Ki values for the Na+/H+ antiport. At concentrations that stimulate hepatocyte DNA synthesis, some liver tumor promoters phenobarbital (PB) and HCH, were found to cause a rapid rise pHi in isolated hepatocytes which was sensitive to amiloride and its analogues. Taken together, our data suggest that activation of Na+/H+ antiport activity may be one mechanism whereby some liver tumor promoters stimulate hepatocytes DNA synthesis. This study has implications for the mechanisms of tumor promotion in liver carcinogenesis. © 2003 Wiley‐Liss, Inc.
Cyclooxygenase and cytochrome P‐450 pathways induced by fetal calf serum regulate wound closure in 3T6 fibroblast cultures through the effect of prostaglandin E2 and 12 and 20 hydroxyeicosatetraenoic acids
Authors: Moreno Juan Jose
Published: February 2003

Wound‐induced injury of 3T6 fibroblast cultures initiated a repair process stimulated by fetal calf serum (FCS) that restored the integrity of cell cultures. In these experimental conditions, FCS induced arachidonic acid (AA) release and eicosanoid production. Our results show that the inhibition of the cyclooxygenase (COX) and/or cytochrome P‐450 pathways significantly decreases the wound closure, whereas that of the lipoxygenase pathway does not modify the wound repair process. Both EP1 and EP4 receptors of prostaglandin E2 (PGE2) mediate PGE2 stimulated 3T6 fibroblast wound closure. Our data suggest that calcium and cAMP are involved in the signaling event induced by PGE2 during the 3T6 fibroblast wound repair process. On the other hand, we show that ketoconazole, a cytochrome P‐450 inhibitor, hinders the wound closure induced by FCS in wounded 3T6 fibroblast cultures. 12 and 20 Hydroxyeicosatetraenoic acids (HETEs), which are key AA metabolites synthesized by cytochrome P‐450, partially revert the effects of ketoconazole on the wound repair process. Thus, the COX and cytochrome P‐450 pathways of the arachidonate cascade are involved in 3T6 fibroblast wound closure. © 2003 Wiley‐Liss, Inc.