bluuebunny/crossref_metadata_2025 huggingface dataset:
Key issues involved with the use of miniature specimens in the characterization of the mechanical behavior of polymeric biomaterials—A review
Authors: Lewis Gladius
Published: September 2002

This article is arranged in three parts. In the first, a brief history of the use of miniature specimens for characterizing the mechanical behavior of materials in general is given. In the second part, several trends in literature reports of small punch and small shear punch tests of ultra‐high‐molecular‐weight polyethylene and acrylic bone cement specimens are examined critically. In this exercise, special attention is paid to one test metric; namely, the work to failure [which is the area under the punch load (P) versus punch displacement (Δ) plot up to the failure point]. In the third part of the article, seven key issues in this field are discussed. In each case, the gaps in the current knowledge base are pointed out. Among those issues are determination of sensitivity of test results to test variables, development of methods for converting P−Δ results to bulk material properties, and constitutive modeling of the mechanical behavior of a polymeric biomaterial, under both small punch and small shear punch loading. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 455–466, 2002
Biomembranes enriched with TGFβ1 favor bone matrix protein expression by human osteoblasts in vitro
Authors: Lilli C. , Marinucci L. , Stabellini G. , Belcastro S. , Becchetti E. , Balducci C. , Staffolani N. , Locci P.
Published: September 2002

The use of growth factors in oral tissue regeneration is currently under investigation. When growth factors are combined with commercial materials, the in vitro mechanisms of action still remain unclear. The present study first evaluated the capacity of barrier membranes, used in oral surgery, to sequester TGFβ1. Resorbable HYAFF, paroguide, poly DL‐lactide and nonresorbable PTFE membranes were immersed in MEM containing 0.2 ng 125I‐TGFβ1 for different periods of time. It was found that HYAFF membrane and paroguide sequestered the most TGFβ1, which was then released in its active form (as shown by the CCL64 cell line bioassay). Untreated membranes and membranes enriched with TGFβ1 were then used as substrate for human bone cells to evaluate the synthesis of the osteoblast phenotype, as indicated by specific parameters. Results showed that membranes enriched with TGFβ1 increased alkaline phosphatase activity, collagen, and osteocalcin production more than untreated membranes. HYAFF and paroguide membranes, which sequestered the most of TGFβ1, were the most suitable for stimulating bone matrix proteins. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 577–582, 2002
Long‐term biocompatibility of implanted polymer‐based intrafascicular electrodes
Authors: Lawrence Stephen M. , Larsen Jytte O. , Horch Kenneth W. , Riso Ron , Sinkjær Thomas
Published: September 2002

Polymer‐based longitudinal intrafascicular electrodes (polyLIFEs) were chronically implanted into the sciatic nerve of white New Zealand rabbits (n=8) for a period of 6 months (hereafter referred to as the long‐term group). The impact of the implantation procedure, as observed 6 months post surgery, was evaluated in a sham‐treated control group (n=9). The contralateral sciatic nerve served as the control for each animal. Nerve‐fiber counts, fiber diameters, and myelin thickness were estimated at the level of the implant site, 1.5 cm proximally, and 1.5 cm distally for both nerves in sham‐treated and long‐term groups. Implantation of polyLIFEs had no significant effect on fiber counts, nerve‐fiber diameter, or myelin thickness. A slight increase in connective tissue in the vicinity of the implant site was evident in the long‐term group, including a thin but dense capsule immediately surrounding the implanted electrode. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 501–506, 2002
Morphologic and immunohistochemical observations of tissues surrounding retrieved transvenous pacemaker leads
Authors: Esposito Marco , Kennergren Charles , Holmström Nils , Nilsson Susanne , Eckerdal Johan , Thomsen Peter
Published: September 2002

Immunohistochemical and morphologic techniques were employed to evaluate the tissue response around chronically implanted pacing leads. Seventeen leads were retrieved from 12 patients. Leads were extracted by direct manual traction (1), extraction with sheaths and locking stylets (1), or with by a combination of mechanical tools and Excimer laser sheaths (15). Mean lead implantation time was 5.6 years (range 1–8 years). Frozen sections, 6–8 μm thick, were incubated with antibodies against HLA‐DR antigen, endothelial cells, macrophages, T cells, plasma cells, fibrinogen, and interleukin‐1β. Prominent morphologic observations were fibrous encapsulations of the leads. Immunohistochemical analysis revealed a tissue generally devoid of inflammatory and immune cells. The fibrous capsule surrounding the lead was partially or completely covered with a monolayer of CD34 expressing endothelial cells. The results from this study provide useful information in design and material selection for pacemaker leads. Endothelialization of the fibrous encapsulation indicates a functionalization of blood‐contacting surfaces around pacemaker materials, thus providing a mechanism for long‐term persistence of foreign materials in the blood. The laser method allowed an efficient extraction of pacemaker leads without damage to the studied tissues, as suggested by the presence of immunolabeled cells close to the cut surfaces. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 548–558, 2002
Biological reactivity of zirconia–hydroxyapatite composites
Authors: Silva Viviane V. , Lameiras Fernando S. , Lobato Zélia I. P.
Published: September 2002

Materials and devices intended for end‐use applications as implants and medical devices must be evaluated to determine their biocompatibility potential in contact with physiological systems. The use of standard practices of biological testing provides a reasonable level of confidence concerning the response of a living organism to a given material or device, as well as guidance in selecting the proper procedures to be carried out for the screening of new or modified materials. This article presents results from cytotoxicity assays of cell culture, skin irritation, and acute toxicity by systemic and intracutaneous injections for powders, ceramic bodies, and extract liquids of hydroxyapatite (HA), calcia partially stabilized zirconia (ZO), and two types of zirconia–hydroxyapatite composites (Z4H6 and Z6H4) with potential for future use as orthopedic and dental implants. They indicate that these materials present potential for this type of application because they meet the requirements of the standard practices recommended for evaluating the biological reactivity of ATCC cell cultures (CCL1 NCTC clone 929 of mouse connective tissue and CCL 81 of monkey connective tissue) and animals (rabbit and mouse) with direct or indirect patient contact, or by the injection of specific extracts prepared from the material under test. In addition, studies involving short‐term intramuscular and long‐term implantation assays to estimate the reaction of living tissue to the composites studied, and investigations on long‐term effects that these materials can cause on the cellular metabolism, are already in progress. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 583–590, 2002
Deconvolution of surface topology for quantification of initial wear in highly cross‐linked acetabular components for THA
Authors: Kurtz S. M. , Turner J. L. , Herr M. , Edidin A. A.
Published: September 2002

Evaluation of the surface morphology of short‐term retrieved cross‐linked acetabular components requires differentiation between the features generated during machining and the smaller‐scale morphologies generated during the in vivo wear process. Previously, the distinction between the waviness of machining and the roughness of wear has been related to the grain size of the UHMWPE. Here a low‐frequency cutoff is proposed, based on the maximum spectral frequency of machining marks, rather than on the grain size of the bulk UHMWPE material, as a reliable method for deconvolving machining marks from in vivo wear following short‐term implantation. To this end, as‐machined articulating surfaces of conventional (GUR 1050) and two groups of highly cross‐linked UHMWPE acetabular components were examined to determine whether they exhibited a periodic surface morphology with a well‐defined spatial frequency. The surface frequency spectra revealed low‐frequency peaks associated with the machining marks, which were unique to each type of implant. Furthermore, the surface frequency spectra appeared uniform within a single group of implants. Statistically significant differences in the surface roughness and waviness were observed between the three groups of new implants. Our research suggests that machining marks can be effectively deconvolved from the articulating surface with the use of a Fourier transform algorithm with a single cutoff frequency of 0.08 1/μm, corresponding to a wavelength of 12.5 μm. The results of this study provide a unified conceptual framework for discriminating between waviness and roughness of the articulating surface for machined orthopedic components. The distinction between waviness and roughness is expected to be crucial for the comprehensive evaluation of wear surfaces after short‐term implantation, when machining marks may be partially worn away or plastically deformed in vivo. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 492–500, 2002
Comparison of two methods to measure permeability of dentin
Authors: De La Macorra Jose C. , Escribano Nuria I.
Published: September 2002

Dentin permeability was measured alternatively with two methods: a 10‐μl capillary method with visual evaluation (PC) and a motorized automatic measuring device (Flodec, FD), both interposed in a simulated perfusion system. Eight human third molar coronal fragments were connected to systems, and their permeability to distilled water measured at 0, 5, 10, 15, 20, 25, and 29 cm H2O pressure. Resultant permeabilities (in μl/s) for both techniques were interrelated with the use of the Passing and Bablok nonparametric method, which gives information about the range of constant and proportional errors and their 95% confidence intervals (95CI). The relationship between the methods is described by the regression formula: FD = −0.0003 + 0.945·PC, with 95CI for constant (−0.0015–0.0009) and for slope (0.738–1.168), indicating that both methods are interchangeable, although not identical. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 531–534, 2002
Effect of bleaching agents on the fluoride release and microhardness of dental materials4
Authors: Lee J. H. , Kim H. I. , Kim K. H. , Kwon Y. H.
Published: September 2002

The use of bleaching agents has become a popular procedure for whitening teeth. Recently introduced polyacid‐modified composite resins (compomers) have several favorable features, such as improved physical properties and fluoride release. Because these two materials have many possibilities to interact in the oral cavity during dental treatment, it is necessary to understand such interaction. To evaluate the effect of a bleaching agent on dental restoratives, three compomers were photopolymerized and then bleached for 1, 2, 3 and 5 days with the use of 30% hydrogen peroxide. Fluoride release, surface microhardness, and surface modifications were evaluated. It was found that the cumulative fluoride release was found to be linearly correlated to the tested periods of bleaching in all compomers. Among the tested compomers, F2000 showed the highest cumulative fluoride release. Bleached compomers became soft because of surface degradation, so the surface microhardness decreased. F2000 showed an apparent crack formation that was not observed in other compomers. The nearly linear correlation between the filler content and microhardness was found in the control samples. However, the same correlation was not observed after the compomers were stored in a bleaching agent or distilled water. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 535–541, 2002
Fabrication and surface modification of macroporous poly(L‐lactic acid) and poly(L‐lactic‐co‐glycolic acid) (70/30) cell scaffolds for human skin fibroblast cell culture
Authors: Yang Jian , Shi Guixin , Bei Jianzhong , Wang Shenguo , Cao Yilin , Shang Qingxin , Yang Guanghui , Wang Wenjing
Published: September 2002

The fabrication and surface modification of a porous cell scaffold are very important in tissue engineering. Of most concern are high‐density cell seeding, nutrient and oxygen supply, and cell affinity. In the present study, poly(L‐lactic acid) and poly(L‐lactic‐co‐glycolic acid) (70/30) cell scaffolds with different pore structures were fabricated. An improved method based on Archimedes' Principle for measuring the porosity of scaffolds, using a density bottle, was developed. Anhydrous ammonia plasma treatment was used to modify surface properties to improve the cell affinity of the scaffolds. The results show that hydrophilicity and surface energy were improved. The polar N‐containing groups and positive charged groups also were incorporated into the sample surface. A low‐temperature treatment was used to maintain the plasma‐modified surface properties effectively. It would do help to the further application of plasma treatment technique. Cell culture results showed that pores smaller than 160 μm are suitable for human skin fibroblast cell growth. Cell seeding efficiency was maintained at above 99%, which is better than the efficiency achieved with the common method of prewetting by ethanol. The plasma‐treatment method also helped to resolve the problem of cell loss during cell seeding, and the negative effects of the ethanol trace on cell culture were avoided. The results suggest that anhydrous ammonia plasma treatment enhances the cell affinity of porous scaffolds. Mass transport issues also have been considered. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 438–446, 2002
Theoretical investigation of elastic flexural properties for multistranded orthodontic archwires
Authors: Rucker Brian K. , Kusy Robert P.
Published: September 2002

The bending and torsional stresses during flexure were detailed and simplified for a single twisted strand, which emulates a spring. General expressions were derived to evaluate the elastic properties (i.e., strength, stiffness, and range) of multistranded wires by combining the effects of a number of outer twisted strands, with or without an inner strand. Specific expressions were solved for single‐stranded, twisted, and coaxial wires. Initially, we considered the following multistranded wire configurations: two‐ (twin), three‐ (triple), four‐strand (quad) twisted, and coaxial wires. The elastic properties of the twin and quad wires were essentially subsets of the triple wire. For a given overall wire diameter (D) and helix angle (α), the ranges of multistranded wires were independent of wire configurations. By varying the α from 45 to 85°, the D from 0.394 to 0.546 mm (15.5 to 21.5 mil), and the stress at the proportional limit from 1.03 to 3.28 GPa (150 to 475 ksi), the theoretical elastic properties of triple and coaxial stainless steel wires matched many of the properties of conventional nickel titanium leveling wires. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 338–349, 2002
Evaluation of feasibility of hydroxyapatite putty as a local hemostatic agent for bone
Authors: Momota Yukihiro , Miyamoto Youji , Ishikawa Kunio , Takechi Masaaki , Yuasa Tetsuya , Tatehara Seiko , Nagayama Masaru , Suzuki Kazuomi
Published: September 2002

Although bone wax is known to cause an inflammatory reaction in soft tissue and a delay of bone healing, it is usually the first choice to arrest bleeding from bone. Hydroxyapatite (HAP) putty is proposed here. This study evaluated the feasibility of HAP putty with respect to whether or not it has potential value as a hemostatic agent for bone. First, the adhesive strength of HAP putty to bone was evaluated. The adhesive strength of HAP putty to wet bone was much higher when compared with that of bone wax, even though the adhesive strengths of HAP putty and bone wax to dry bone were equivalent. Next, to evaluate the hemostatic ability of HAP putty, bony defects were made in rabbits. HAP putty could arrest bleeding from bone within 3 min. However, when the hemostasis was performed with bone wax, bleeding was arrested within 8 min. Thus, HAP putty showed better hemostatic ability than bone wax. Finally, the tissue response to HAP putty in rabbit subcutaneous tissue was evaluated. Histological observation revealed a slight inflammatory response around HAP putty, whereas bone wax was surrounded by moderate inflammatory tissue. In conclusion, HAP putty has good potential value to be a hemostatic agent for bone because it has strong adhesion, good hemostatic ability, and biocompatibility. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 542–547, 2002
Theoretical prediction and experimental determination of the effect of mold characteristics on temperature and monomer conversion fraction profiles during polymerization of a PMMA‐based bone cement
Authors: Vallo Claudia I.
Published: September 2002

The present work is concerned with applications of a kinetic model for free‐radical polymerization of a polymethylmethacrylate‐based bone cement. Autocatalytic behavior at the first part of the reaction as well as a diffusion control phenomenon near vitrification are described by the model. Comparison of theoretical computations with experimental measurements for the temperature evolution during batch casting demonstrated the capacity of the proposed model to represent the kinetic behavior of the polymerization reaction. Temperature evolution and monomer conversion were simulated for the cure of the cement in molds made of different materials. The maximum monomer conversion fraction was markedly influenced by the physical properties of the mold material. The unreacted monomer acts as a plasticizer that influences the mechanical behavior of the cement. Hence, the same cement formulation cured in molds of different materials may result in different mechanical response because of the differences in the amounts of residual monomer. Standardization of the mold type to prepare specimens for the mechanical characterization of bone cements is recommended. Theoretical prediction of temperature evolution during hip replacement indicated that for cement thickness lower than 6 mm the peak temperature at the bone–cement interface was below the limit stated for thermal injury (50 °C for more than 1 min). The use of thin cement layers is recommended to diminish the risk of thermal injury; however, it is accompanied by an increase in the amount of unreacted monomer present in the cured material. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 627–642, 2002
A jet impingement investigation of osteoblastic cell adhesion
Authors: Giliberti Danielle C. , Anderson Kimberly A. , Dee Kay C
Published: September 2002

When designing dental and orthopedic implants, it is important to consider phenomena occurring at the microscopic level, particularly at the bone‐implant interface. The presence of hard tissue at this interface is essential to implant viability. The integrity of this tissue‐biomaterial interface is dependent on appropriate osteoblast functions (adhesion, matrix deposition, etc.) in the immediate area. Researchers have modified various materials with cell‐adhesive peptides with the ultimate goal of controlling osteoblast functions. This study used microjet impingement to compare the strength of adhesion of osteoblastic cells (at varying populations) and fibroblasts to peptide‐modified substrates in the presence and absence of fetal bovine serum. In the presence of the serum, there was no significant difference in cellular adhesion strength between substrates. In the absence of serum, all cells tested adhered more strongly to underlying substrates, and the strength of cellular adhesion was greater on modified surfaces than on plain glass surfaces. In the absence of serum, second‐passage osteoblastic cells generally adhered to substrates more strongly than first‐passage osteoblastic cells; fibroblasts adhered similarly to second‐passage osteoblastic cells. Fundamental studies such as the present increase the understanding of cell adhesion to various substrates—knowledge that may be ultimately useful in creating an optimal bone‐implant interface. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 422–429, 2002
Tissue responses against immunoisolating alginate‐PLL capsules in the immediate posttransplant period
Authors: de Vos Paul , van Hoogmoed Chris G. , de Haan Bart J. , Busscher Henk J.
Published: September 2002

Alginate‐polylysine (PLL) capsules are commonly applied for immunoisolation of living cells for the treatment of a wide variety of diseases. Large‐scale application of the technique, however, is hampered by insufficient biocompatibility of the capsules with failure of the grafts as a consequence. Most studies addressing biocompatibility issues of alginate‐PLL capsules have focused on the degree of overgrowth on the capsules after graft failure and not on the reaction against the capsules in the immediate posttransplant period. Therefore, capsules were implanted in the peritoneal cavity of rats and retrieved 1, 5, and 7 days later for histological examination and X‐ray photoelectron spectroscopy analysis for evaluation of chemical changes at the capsule surface. After implantation, the nitrogen signal increased from 5% on day 0, to 8.6% on day 7, illustrating protein adsorption on the capsule's surface. This increase in protein content of the membrane was accompanied by an increase in the percentage of overgrown capsules from 0.5 ± 0.3% on day 1 to 3.3 ± 1.6% on day 7. The cellular overgrowth was composed of monocytes/macrophages, granulocytes, fibroblasts, erythrocytes, multinucleated giant cells, and basophils. This overgrowth was not statical as generally assumed but rather dynamic as illustrated by our observation that at day 1 after implantation we mainly found monocytes/macrophages and granulocytes that on later time points were substituted by fibroblasts. As the inflammatory reaction predictably interfere with survival of encapsulated cells, efforts should be made to suppress activities or recruitment of inflammatory cells. These efforts may be temporary rather than permanent because most inflammatory cells have disappeared after 2 weeks of implantation. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 430–437, 2002
Extracellular matrix of human amnion manufactured into tubes as conduits for peripheral nerve regeneration
Authors: Mligiliche Nurru , Endo Katsuaki , Okamoto Keiko , Fujimoto Etsuko , Ide Chizuka
Published: September 2002

The human amnion consists of the epithelial cell layer and underlying connective tissue. After removing the epithelial cells, the resulting acellular connective tissue matrix was manufactured into thin dry sheets called amnion matrix sheets. The sheets were further processed into tubes, amnion matrix tubes (AMTs), of varying diameters, with the walls of varying numbers of amnion matrix sheets with or without a gelatin coating. The AMTs were implanted into rat sciatic nerves. Regenerating nerves extended in bundles through tubes of 1–2 mm in diameter and further elongated into host distal nerves 1–3 weeks after implantation. Morphometrical analysis of the regenerated nerve cable at the middle of each amnion matrix tube 3 weeks after implantation was performed. The average numbers of myelinated axons were almost the same (ca. 80–112/104 μm2) in AMTs of 1–2 mm in diameter, as in the normal sciatic nerve (ca. 95/104 μm2). No myelinated fibers were found in AMTs composed of multiple thin tubes of 0.2 mm in diameter. The myelinated axons were thinner in implanted tubes than those in the normal sciatic nerve. The rate of occurrences of myelinated axons less than 4 μm in diameter was significantly higher in the AMTs, whereas axons in the normal sciatic nerve were diverse in distribution, with the highest population at 8–12 μm in diameter. Reinnervation to the gastrocnemius muscle was demonstrated electrophysiologically 9 months after implantation. It was concluded that the extracellular matrix sheet from the human amnion is an effective conduit material for peripheral nerve regeneration. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 591–600, 2002
Effect of ball milling on the processing of bone substitutes with calcium phosphate powders
Authors: Bignon Aurélien , Chevalier Jérôme , Fantozzi Gilbert
Published: September 2002

Decreasing the microscale morphology of synthetic bone substitutes is of primary importance in order to enhance the morphology of the surface of the material, which is directly in contact with osteoconductive cells when it is implanted in bone. The aim of this study was to investigate the influence of ball milling of slurries on the microscale morphology of hydroxyapatite and tricalcium phosphate bone substitutes and the influence on their processing. Ball milling appeared to be a successful method in order to raise the sintering reactivity of the powders, that is, to decrease the sintering temperature and microstructural morphology of the material. However, it was demonstrated that ball milling had a great influence on dispersion, which became very difficult under long milling times because of dissolution of the calcium phosphate powders. Due to dissolution, ionic species were generated in the slurry and interfered with the dispersing agent. Moreover a reprecipitation process occurred simultaneously, and large particles of the most stable phase (HAP) formed. The presence of such large particles generated stress gradients and cracks in the material during the sintering stage. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 619–626, 2002
Effect of surface conditions on the color of dental resin composites
Authors: Lee Yong‐Keun , Lim Bum‐Soon , Kim Cheol‐We
Published: September 2002

The objectives of this study were to evaluate the effect of surface conditions of dental resin composites on the measured color depending on the measuring geometry (SCE, SCI), and to determine the color difference (ΔE*) caused by varied surface conditions. Color and surface roughness (Ra) of five brands of resin composites of A2 shade were measured after polymerization and polishing with 600‐, 1000‐, or 1500‐grit SiC paper. Color was measured according to the CIE L*a*b* color scale. ΔE* between different surface conditions was calculated by the equation ΔE* = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2. Before polishing, CIE L* values with the SCE were significantly lower than those measured with the SCI. Before polishing, ΔE* values depending on the measuring geometry were very high (3.78–5.93). However, those after polishing were lower than 1.61. CIE L* values increased after polishing (p < 0.05) with the SCE; however, they were not changed with the SCI. ΔE* values between Mylar‐covered and 600‐grit polished specimens were 4.20–5.99 with the SCE and 0.27–1.46 with the SCI. Measurement with the SCE geometry may result in accurate color determination, which reflects the surface conditions of dental restorative materials. ΔE* values measured with the SCE between the specimens of different surface conditions were significantly higher than those with the SCI (p < 0.05). © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 657–663, 2002
A field‐focusing device to increase power output of ThermoRod™ implants for thermal ablation of tissue
Authors: Berthusen Andrew H. , Tucker Robert D. , Park Joon B.
Published: September 2002

Induction heating of small, cylindrical ferromagnetic implants (1.4 cm long and 1 mm in diameter) is a method for treating deep‐seated tumors. These implants, or ThermoRods™, are placed within a lesion in 1‐cm2 arrays and are exposed to an alternating magnetic field. The implants absorb energy from that field and transfer it as heat to the surrounding tissue. Each ThermoRod™ offers approximately 400 mW of power, and to kill cells, the target temperature must be greater than 42 °C. In this work, a magnetic field‐focusing device is employed to concentrate the induced magnetic flux toward a local region near the base of the prostate to increase the power output of proximal ThermoRods™. This, in turn, allows for more complete thermal ablation of lesions near the base of the prostate where the heat‐sink characteristics of the bladder can cause significant power losses. Boundary element analysis and in vitro testing have shown that the use of a ferrofluid‐based field‐focusing device can lead to a significant increase in power output of approximately 25% and 13%, respectively, of proximal ThermoRods™. These preliminary results indicate that the incorporation of such a ferrofluid‐based focusing device into ThermoRod™ treatments is promising for the avoidance of significant power loss and for assuring complete thermal ablation of prostatic lesions. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 650–656, 2002
Glucose‐dependent regulation of osteoclast H+‐ATPase expression: Potential role of p38 MAP‐kinase
Authors: Larsen Kirsten I. , Falany Marina L. , Ponomareva Larissa V. , Wang Wei , Williams John P.
Published: September 2002

Bone resorption is glucose concentration dependent. Mechanisms regulating glucose‐dependent increases in bone resorption have not been identified. Glucose activates p38 MAP‐kinase in other cells and since MAP kinases activate transcription factors, we hypothesized that glucose‐stimulated bone resorption may be modulated by increased expression of the vacuolar H+‐ATPase. Glucose activates osteoclast p38 MAP‐kinase in a time and concentration‐dependent manner as determined by Western analysis with phospho‐specific p38 antibody while total p38 levels are unchanged. The K0.5 for glucose‐dependent activation of p38 MAP‐kinase is ∼7 mM, activation is maximal at 30 min and is elevated but returning to basal levels by 60 min. The concentration‐dependent increase in H+‐ATPase expression was confirmed by Northern analysis. The specific inhibitor of p38 MAP‐kinase, SB203580, inhibited glucose transport in osteoclasts, as well as glucose concentration‐dependent increases in bone resorption and expression of H+‐ATPase A and B subunits. Glucose had no effect on calmodulin expression levels that are regulated in response to other environmental changes. The glucose‐stimulated increase in H+‐ATPase mRNA expression is a specific response to glucose since glucose has little effect on G3PDH mRNA levels. We conclude that glucose regulates osteoclast H+‐ATPase expression by a mechanism likely to involve p38 MAP‐kinase. J. Cell. Biochem. 87: 75–84, 2002. © 2002 Wiley‐Liss, Inc.
Further characterization of human fetal osteoblastic hFOB 1.19 and hFOB/ERα cells: Bone formation in vivo and karyotype analysis using multicolor fluorescent in situ hybridization
Authors: Subramaniam M. , Jalal Syed M. , Rickard David J. , Harris Steven A. , Bolander Mark E. , Spelsberg Thomas C.
Published: September 2002

We have previously generated an immortalized human fetal osteoblastic cell line (hFOB) using stably transfected temperature sensitive SV40 T‐antigen (Harris et al. [1995a] J. Bone. Miner. Res. 10:178–1860). To characterize these cells for phenotypic/genotypic attributes desired for a good cell model system, we performed karyotype analysis by multicolor fluorescent in situ hybridization (M‐FISH), their ability to form bone in vivo without developing cell transformation, and finally their ability to form extracellular matrix formation in vitro. The karyotype analysis of hFOB cells revealed structural or numeric anomalies involving 1–2 chromosomes. In contrast, the human osteosarcoma MG63 cells displayed multiple, and often complex, numeric, and structural abnormalities. Subcutaneous injection of hFOB cells in the presence of Matrigel into nude mice resulted in bone formation after 2–3 weeks. Electron microscopic analysis of the extracellular matrix deposited by hFOB cells in culture revealed a parallel array of lightly banded fibrils typical of the fibrillar collagens such as type I and III. These results demonstrate that the hFOB cell line has minimal chromosome abnormalities, exhibit the matrix synthetic properties of differentiated osteoblasts, and are immortalized but non‐transformed cell line. These hFOB cells thus appear to be an excellent model system for the study of osteoblast biology in vitro. J. Cell. Biochem. 87: 9–15, 2002. © 2002 Wiley‐Liss, Inc.
Identification of cultured progenitor cells from human marrow stroma
Authors: Shur I. , Marom R. , Lokiec F. , Socher R. , Benayahu D.
Published: September 2002

The marrow stromal cells (MSC) are essential for regulation of bone remodeling and hematopoiesis. It is of prime importance to isolate MSC and to expand the proliferating cells ex vivo. In this study, we analyzed cultured MSC for various cellular parameters, including cell morphology, cell cycle, and expression of cell surface antigens by flow cytometry. MSC were divided based on cell size to small (S‐cells) and large (L‐cells) and were visualized by light and electron microscope. The S‐cells were proliferating cells correlated with G0/G1 phase of cell cycle, and expressed cFOS. The expression of surface markers CD‐34, ‐44, ‐51, ‐61, ‐62E, ‐62P, ‐62L was quantified using flow cytometry. CD‐44 was ubiquitously expressed by S and L cells, CD‐51 and ‐61 were expressed by 30%–38% of S‐cells. CD‐34 and ‐62 expressed 20% positive of the analyzed cells that were of the proliferating progenitors (S‐cells). This study enables the identification of subpopulations from MSC with special attention paid to the proliferating cells from ex vivo cultures of marrow stroma. J. Cell. Biochem. 87: 51–57, 2002. © 2002 Wiley‐Liss, Inc.
Arsenic induces oxidative stress and activates stress gene expressions in cultured lung epithelial cells
Authors: Li Muyao , Cai Jiu‐Feng , Chiu Jen‐Fu
Published: September 2002

Chronic exposure to low levels of arsenic can cause lung cancer. However, the cellular and molecular mechanisms for lung cell transformation in response to arsenic are not known. These studies investigated the hypothesis that low levels of arsenic increase intracellular oxidant levels, promote production of mitogenic transcription factors and antioxidant enzymes. Initially, arsenic decreased GSH cellular level and rapidly increased to 280% of GSH level in nonexposed lung cells in 24 h. Buthionine sulfoximine (BSO) potentiated the arsenic toxicity of lung epithelial cells (LEC). Exposure of LEC to 5 μM arsenite cause time‐dependent increase in γ‐glutamylcysteine synthetase (γ‐GCS) expression. Our data demonstrated that arsenic induced the heavy subunit of γ‐GCS (γ‐GCS‐HS) mRNA levels as early as 4 h as compared to the control level. It significantly increased (sixfolds) γ‐GCS‐HS mRNA expression after 8 h of treatment. The activation of AP‐1 transcription factors may also play a regulatory role in this process. Significant elevations in c‐fos and c‐jun mRNA levels were observed within 30 min after exposure to arsenic and by enhancement of AP‐1 DNA binding activity and transactivation activity. Responsiveness of LEC to oxidative stress caused by arsenic exposure was further evaluated with mobility shift assay involving redox‐sensitive transcription factor NF‐κB. The specificity of binding was verified by an antibody‐supershift. The NF‐κB DNA binding activities increased more than twofold 30 min after exposure to arsenic and returned to control levels after 4 h of treatment. It remains to be determined whether NF‐κB plays a role in the As‐induced apoptosis or alternatively in attempting to protect the cells from As‐induced cell death by upregulating the expression of resistance factors. J. Cell. Biochem. 87: 29–38, 2002. © 2002 Wiley‐Liss, Inc.
Microgravity modifies protein kinase C isoform translocation in the human monocytic cell line U937 and human peripheral blood T‐cells
Authors: Hatton Jason P. , Gaubert Francois , Cazenave Jean‐Pierre , Schmitt Didier
Published: September 2002

Individual protein kinase C (PKC) isoforms fulfil distinct roles in the regulation of the commitment to differentiation, cell cycle arrest, and apoptosis in both monocytes and T‐cells. The human monocyte like cell line U937 and T‐cells were exposed to microgravity, during spaceflight and the translocation (a critical step in PKC signaling) of individual isoforms to cell particulate fraction examined. PKC activating phorbol esters induced a rapid translocation of several PKC isoforms to the particulate fraction of U937 monocytes under terrestrial gravity (1g) conditions in the laboratory. In microgravity, the translocation of PKC βII, δ, and ε in response to phorbol esters was reduced in microgravity compared to 1g, but was enhanced in weak hypergravity (1.4g). All isoforms showed a net increase in particulate PKC following phorbol ester stimulation, except PKC δ which showed a net decrease in microgravity. In T‐cells, phorbol ester induced translocation of PKC δ was reduced in microgravity, compared to 1g, while PKC βII translocation was not significantly different at the two g‐levels. These data show that microgravity differentially alters the translocation of individual PKC isoforms in monocytes and T‐cells, thus providing a partial explanation for the modifications previously observed in the activation of these cell types under microgravity. J. Cell. Biochem. 87: 39–50, 2002. © 2002 Wiley‐Liss, Inc.
Purification and characterization of the active form of tyrosine hydroxylase from mesangial cells in culture
Authors: Yuri Arita Danielle , Seno Di Marco Giovana , Schor Nestor , Casarini Dulce Elena
Published: September 2002

The capacity of mesangial cells (MC) to produce catecholamines (CAs) has been investigated in our laboratory. To study the CA cascade, it is necessary to examine some steps in their metabolic pathway. Tyrosine hydroxylase (TH) catalyzes the rate‐limiting step in the biosynthesis of these biogenic amines (dopamine (DA), norepinephrine (NE), and epinephrine (EPI)). Since the glomerular mesangium is their target in the regulation of renal sodium transport and renin secretion, the aim of the study was to determine the presence of TH in these cells in culture. The CA levels were detected in immortalized MC by high‐performance liquid chromatography with electrochemical detection. The following concentrations were found in the intracellular region and in the medium, respectively: NE = 284 ± 31 and 134 ± 22, EPI = 75 ± 14 and 22 ± 5, and DA = 42 ± 14, 40 ± 20 pg/mg cell protein. The enzymatic activity of the cell lysate and medium was measured based on l‐dopa formation. In the presence of o‐phenanthroline, both samples presented 39% inhibition. The biopterin was detected in the intracellular and in the medium (64.87 and 631.99 pmol/mg protein, respectively) using high‐performance liquid chromatography with ultraviolet detection. The cell lysate was submitted to a DEAE‐Sephacel column, followed by gel filtration, and Heparin‐Sepharose. TH was purified 613.16‐fold with a specific activity of 466.0 pg/mg cell protein. Immunoblotting using monoclonal antibody revealed the presence of TH in the different purification steps. Purified TH was sequenced, presenting an alignment with amino‐terminal sequence of mouse enzyme. Our results demonstrated the presence of active TH in MC, suggesting that these cells are able to produce CA “in vivo”, and establishing a convenient purification method for TH that can be applied to the study of the molecular properties of the enzyme modified “in vivo” by different physiological and pathophysiological stimuli. J. Cell. Biochem. 87: 58–64, 2002. © 2002 Wiley‐Liss, Inc.
ERK activation and αvβ3 integrin signaling through Shc recruitment in response to mechanical stimulation in human osteoblasts
Authors: Weyts F.A.A. , Li Y.‐S. , van Leeuwen J. , Weinans H. , Chien S.
Published: September 2002

Osteoblast growth and differentiation are critical processes for bone development and maintenance, and are regulated by both humoral and mechanical factors. Humoral (hormonal) factors can affect gene transcription via MAPkinases, e.g., extracellular signal‐regulated kinase (ERK). We studied whether the ERK pathway is also involved in processing mechanical inputs in human bone cells. Exposing MG63 cells to physiologically relevant levels of fluid flow resulted in ERK phosphorylation. Genistein blocked this response, indicating that it is dependent on tyrosine phosphorylation. Furthermore, αvβ3 integrins were activated in response to fluid flow, as shown by recruitment of adaptor molecule Shc and clustering of αvβ3 in focal adhesion‐like structures. Antibodies blocking formation of β1 or β3 integrin‐matrix interactions or RGD peptides could not inhibit fluid flow‐induced ERK phosphorylation, suggesting that formation of new integrin‐matrix interactions is not essential for this response and that other upstream mechanosensors regulate induction of ERK phosphorylation in response to fluid flow in human bone cells. J. Cell. Biochem. 87: 85–92, 2002. © 2002 Wiley‐Liss, Inc.
C2PA is a nuclear protein implicated in the heat shock response
Authors: Hirabayashi Susumu , Ohno Hideki , Iida Junko , Hata Yutaka
Published: September 2002

C2PA is a protein of unknown function that is expressed in spermatocytes. PDZ‐RGS3 is a signaling molecule whose PDZ domain binds Ephrin‐B2 and mediates reverse signaling of this protein. C2PA and PDZ‐RGS3 have identical PDZ domains. To explore the function of C2PA, we compared it with PDZ‐RGS3 with respect to tissue distribution, subcellular localization, and biochemistry. C2PA is expressed only in testis, whereas PDZ‐RGS3 is expressed in various tissues including brain, heart, lung, liver, spleen, kidney, small intestine, skeletal muscles, and testis. These proteins also differ in their subcellular distribution, in that PDZ‐RGS3 is cytosolic while C2PA is exclusively nuclear. C2PA is distributed diffusely in the nucleus and forms a few foci at 37°C. However, when cells are exposed to 42°C, the number of C2PA foci is increased. These heat shock‐induced foci colocalize with CREB‐binding protein and heat shock factor‐1. In contrast, the distribution of PDZ‐RGS3 does not change during heat stress. When overexpressed, C2PA induces heat shock response element (HSE)‐dependent gene transcription, whereas PDZ‐RGS3 does not. These data suggest that the function of C2PA is distinct from that of PDZ‐RGS3, and that C2PA may be involved in the heat shock response in testis. J. Cell. Biochem. 87: 65–74, 2002. © 2002 Wiley‐Liss, Inc.
Use of the reasons for depression questionnaire with adolescents
Authors: Fitzgerald John M. , Richardson Hayley
Published: September 2002

The Reasons For Depression Questionnaire (RFD) was developed to examine the explanations that people give for being depressed. In its original form it was evaluated with samples of non‐depressed and depressed university students and other adults. The data reported here were used to evaluate the use of the RFD with a community sample of New Zealand adolescents. While the underlying eight‐factor structure reported by the original authors was confirmed, with the addition of a ninth biological factor, additional principal component‐factor analysis supported the existence of a six‐factor solution for adolescents. The revised factor structure incorporated a revision of the scale's item content. It is proposed that an abbreviated scale (RFD‐A) using 35 of the original 48 items would be more appropriate for use with adolescents. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 1045–1056, 2002.
The Existential Loneliness Questionnaire: Background, development, and preliminary findings
Authors: Mayers Aviva M. , Khoo Siek‐Toon , Svartberg Martin
Published: September 2002

We described the background and the development of a new measure of existential loneliness, the Existential Loneliness Questionnaire (ELQ). Specifically, we analyzed the items of the preliminary version of the ELQ (ELQ‐P) using methods based on item response theory (the Rasch model) and examined the convergent and discriminative validity of the ELQ in a sample of 47 HIV‐infected women. Item analysis produced an ELQ version consisting of 22 items that were internally consistent and performed well in measuring an underlying construct conceptualized as existential loneliness. In addition, the ELQ discriminated well between symptomatic and asymptomatic HIV‐infected women. The ELQ correlated strongly with measures of depression, loneliness not identified as existential and purpose‐in‐life and moderately strongly with a measure of hopelessness. Holding constant depression scores, the correlation between the ELQ and loneliness not identified as existential was significantly attenuated. Limitations of the study include the small sample size, which precluded an analysis of the dimensional structure of the ELQ. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 1183–1193, 2002.
Treatment of PTSD: Stress inoculation training with prolonged exposure compared to EMDR
Authors: Lee Christopher , Gavriel Helen , Drummond Peter , Richards Jeff , Greenwald Ricky
Published: September 2002

The effectiveness of Stress Inoculation Training with Prolonged Exposure (SITPE) was compared to Eye Movement Desensitization and Reprocessing (EMDR). Twenty‐four participants who had a diagnosis of Post Traumatic Stress Disorder (PTSD) were randomly assigned to one of the treatment conditions. Participants were also their own wait‐list control. Outcome measures included self‐report and observer‐rated measures of PTSD, and self‐report measures of depression. On global PTSD measures, there were no significant differences between the treatments at the end of therapy. However on the subscale measures of the degree of intrusion symptoms, EMDR did significantly better than SITPE. At follow‐up EMDR was found to lead to greater gains on all measures. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 1071–1089, 2002.
Prediction of personality disorder traits by psychosis proneness scales in a German sample of young adults
Authors: Meyer Thomas D. , Hautzinger Martin
Published: September 2002

Prior research has focused on schizophrenia‐spectrum disorder traits in psychosis‐prone subjects. The whole range of personality disorders were only explored in patient samples and with the relatives of patients. In light of this situation, the predictive value of Physical Anhedonia (PhA), Perceptual Aberration (PER), and Magical Ideation (MI) for personality disorder traits were examined dimensionally and categorically in a non‐patient sample. We selected a non‐student sample (n = 404) and focused on two risk groups (PhA: n = 14; combined PER/MI: n = 36), and a control group (n = 19) using the SCID II to assess personality disorders at a time period two years later. MI explained most of the variance in clinically relevant schizotypal personality disorder symptoms, while PER and PhA dimensionally were associated with the number of diagnostic criteria met for other personality disorders. While both risk groups exceeded the control group in clinically relevant borderline traits, only the PER/MI‐individuals differed in fulfilling more criteria for schizotypal personality disorder. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 1091–1101, 2002.