bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low‐dose, long‐term exposures of dental material components alter human monocyte metabolism
Authors: Noda M. , Wataha J. C. , Lockwood P. E. , Volkmann K. R. , Kaga M. , Sano H. 
Published: October 2002

AbstractThe short‐term degradation of dental polymers and alloys in biological environments has been well documented, but recent evidence indicates that oral tissues may be chronically exposed to low levels of these released components. The effect of these chronic exposures on the ability of cells to respond to a subsequent challenge is not known. To investigate this idea, we exposed human THP‐1 monocytes to sublethal concentrations of HEMA, TEGDMA, Hg2+, and Ni2+ for 2 weeks and then assessed the monocytic response to subsequent 24‐h challenge with the same components at higher concentrations. Chronic (2 week) exposures of monocytes to HEMA and both metal ions significantly altered monocyte response to short‐term (24 h) secondary exposures, even when overt effects of the chronic exposures were not apparent. However, cellular responses were highly variable depending on the material and its concentrations. For TEGDMA, no effects were seen. These results demonstrate that the chronic effects of materials must be considered even when the chronic exposure has no initial overt effect. The effect on cells may only be apparent if the cell is challenged by a secondary exposure. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 237–243, 2002
The effect of polyethylene particle phagocytosis on the viability of mature human macrophages
Authors: Xing S. , Santerre J. P. , Labow R. S. , Boynton E. L. 
Published: October 2002

AbstractMacrophages are the major cell type observed in the inflammatory membrane retrieved at implant revision surgery. In this study, mature human monocyte‐derived macrophages (MDM) were adapted to a previously established in vitro model to examine the influence of high‐density polyethylene (HDPE) particulate (4–10 μm) on MDM viability. HDPE particles were suspended in soluble type I collagen, which subsequently was solidified on glass coverslips. Mature human macrophages, derived from differentiating peripheral blood monocytes on polystyrene for 10 days, were incubated in culture media on collagen controls and collagen–particle substrata for 31 days. Histologic analysis demonstrated that MDMs were in contact with the particles at 2 h. The majority of the particles were associated with the cells within 24 h. Based on electron microscopy, those cells associated with the particles appeared to be morphologically activated rather than necrotic or apoptotic. Assessment of cell viability revealed no differences among the groups at 24 h, but at 31 days significantly more viable cells and higher DNA values were found associated with the particle groups versus the collagen controls. The histologic results validate human mature MDMs as a clinically relevant cell type for study of the role of polyethylene particulate in aseptic loosening. The cell viability results indicate that phagocytosis of HDPE is not toxic to MDMs but in fact prolongs MDM survival. The long‐lived MDMs may play a role in perpetuating chronic inflammation surrounding implants. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 619–627, 2002
Delivery of insulin from hydroxyapatite ceramic microspheres: Preliminary in vivo studies
Authors: Paul Willi , Nesamony Jerry , Sharma Chandra P. 
Published: October 2002

AbstractThe major limiting factor in utilizing protein drugs for sustained delivery is the lack of suitable delivery systems. Ceramic hydroxyapatite microspheres are biocompatible and utilized for the purification of proteins. As a preliminary study, we have investigated the possibility of using hydroxyapatite ceramic microspheres loaded with insulin as an implantable delivery system in rats. With this limited test, it was shown that the loaded insulin was active and able to suppress the blood glucose level in normal rats. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 660–662, 2002
Porous polymer/bioactive glass composites for soft‐to‐hard tissue interfaces
Authors: Zhang Kai , Ma Yue , Francis Lorraine F. 
Published: October 2002

AbstractPorous composites consisting of a polysulfone (or cellulose acetate) matrix and bioactive glass particles were prepared by phase separation techniques. Microstructures were designed for potential application as an interconnect between artificial cartilage and bone. The effects of polymer type, concentration and molecular weight, as well as bioactive glass size and content, on the microstructures of the composites were studied. The composites have asymmetric structures with dense top layers and porous structures beneath. The microstructural features depend most strongly on the type of polymer, the interaction between the polymer and bioactive glass, and the glass content. The dense top layer could be removed by abrasion to make a structure with large pores (20‐150 μm) exposed. Composites were immersed in simulated body fluid at body temperature. The growth of hydroxycarbonate apatite inside and on the composites demonstrates their potential for integration with bone. Composite modulus and break strength increased with increasing glass content due to the change in composition and pore content. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 551–563, 2002
Studies on the tumor promoting mechanism of hard and soft segment models of polyetherurethane: Tyr265 phosphorylation of connexin43 is a key step in the GJIC inhibitory reaction induced by polyetherurethane
Authors: Ichikawa Akira , Tsuchiya Toshie 
Published: October 2002

AbstractGap junctional intercellular communication (GJIC) is inhibited by 4,4′‐di(ethoxycarboamide) diphenylmethane (MDU) and polytetramethylene oxide 1000 (PTMO1000), which are model chemicals of hard and soft segments of polyetherurethane (PEU), respectively. In our previous study, we suggested that the inhibition of GJIC induced by MDU and PTMO1000 may lead to accelerate promotion step by both segments after the initiation step by hard segment, MDU. To examine this hypothesis, we established connexin 43 overexpressed clones from Balb/c 3T3 A31‐1‐1 clones (A31‐1‐1 cells) by transfection. Here we show that these clones acquired much higher GJIC ability than parental A31‐1‐1 cells and kept them even if MDU or PTMO1000 was added to the culture. We also found that Mutation of Cx43 at Tyr‐265 resulted in reduced inhibition of GJIC induced by MDU and PTMO1000. These findings suggest that inhibition of GJIC by PEU may be caused by Tyr‐265 phosphorylation of Cx43 molecule. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 157–162, 2002
Loading of collagen‐heparan sulfate matrices with bFGF promotes angiogenesis and tissue generation in rats
Authors: Pieper J. S. , Hafmans T. , van Wachem P. B. , van Luyn M. J. A. , Brouwer L. A. , Veerkamp J. H. , van Kuppevelt T. H. 
Published: October 2002

AbstractThe loading of biocompatible matrices with growth factors offers the opportunity to induce specific cell behavior. The attachment of heparan sulfate (HS) to these matrices may promote the binding, modulation, and sustained release of signaling molecules. In this study, basic fibroblast growth factor (bFGF) was bound to crosslinked collagenous matrices with and without covalently attached HS. The tissue response to these matrices was evaluated after subcutaneous implantation in rats. Attachment of HS to collagen matrices increased the bFGF binding capacity threefold and resulted in a more gradual and sustained release of the growth factor in vitro. bFGF primarily was located at the matrix margins. In vivo, the presence of HS without bFGF resulted in a transient vascularization, predominantly at the matrix periphery. Angiogenesis was further enhanced by combining HS with bFGF. In contrast to collagen‐HS and collagen/bFGF matrices, collagen‐HS/bFGF matrices remained highly vascularized throughout the matrix during the 10‐week implantation period. In addition, these latter matrices revealed an intense and prolonged tissue response and considerably promoted the generation of new tissue. Foreign body reactions were only observed sporadically at this time interval. It is concluded that bFGF loading of collagen‐HS matrices has additional value for those tissue‐engineering applications that require enhanced angiogenesis and generation of new tissue. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 185–194, 2002
Surface characteristics and dissolution behavior of plasma‐sprayed hydroxyapatite coating
Authors: Sun Limin , Berndt Christopher C. , Khor Khiam Aik , Cheang H. N. , Gross Karlis A. 
Published: October 2002

AbstractOne of the most important concerns with the clinical use of plasma‐sprayed hydroxyapatite (HA) coatings is the resorption of the coating, and dissolution at neutral pH is one of the two major resorption mechanisms. In this study, highly crystalline pure HA powders were atmospherically plasma sprayed using various parameters. Dissolution of both HA powders and coatings was measured using a calcium ion meter. Surface characteristics, including phase, morphology, and roughness, were compared for the coatings before and after dissolution. Pulverized HA coatings exhibited significantly higher dissolution compared with the same quantity of feedstock HA powders because of the decreased crystallinity and fine crystal size of the coating. Furthermore, the dissolution decreased with the crystallinity of the coating. Dissolution of HA coatings did not show much difference with respect to the coatings in the initial stage of immersion (4 h). However, dissolution of all coatings reached saturation in a fresh physiological solution. The saturation values were much lower compared with their counterparts in the form of powders, which may imply the stability of HA coatings in long‐term use. In addition to crystallinity, the particle melting status in the coatings, i.e., the volume of nanocrystals, and porosity, was found to be another important factor for the dissolution of the HA coating. X‐ray diffraction patterns of HA coatings indicated the complete dissolution of impurity phases and amorphous phase after the coatings were immersed in the solution for 4 days. Coatings sprayed at lower power (27.5 kW) exhibited a pattern of crystalline HA whereas coatings sprayed at higher power (42 kW) exhibited a pattern of bone apatite. Surface morphologies showed preferential dissolution of amorphous phase in all coatings accompanied with precipitation of bone apatite observable for coatings sprayed at higher power. Surface roughness measured after the dissolution studies increased for the two coatings sprayed at lower power level but decreased for coatings sprayed at higher power level. This decrease is attributed to the better match in solubility characteristics between the fine crystals and the amorphous calcium phosphate within the coating. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 228–236, 2002
In hereditary hemochromatosis, red cell apheresis removes excess iron twice as fast as manual whole blood phlebotomy
Authors: Muncunill J. , Vaquer P. , Galmés A. , Obrador A. , Parera M. , Bargay J. , Besalduch J. 
Published: October 2002

AbstractThe current treatment of hereditary hemochromatosis (HH) consists of performing periodic manual whole blood phlebotomies. Erythroapheresis (EPH) is considered to be an alternative procedure if the classic treatment is contra‐indicated. A prospective study of 13 consecutive cases of HH were included in a periodic EPH program with the aim of assessing the efficacy, feasibility, and tolerability of EPH in the treatment of HH by induction and maintenance. Iron depletion (ferritin <20 μg/l) was achieved in all patients after a mean of 6.7 ± 2.9 months of treatment and a mean of 13.5 ± 7.2 EPH sessions. The procedure was well tolerated and there were no complications. After a follow‐up period of 10.5 ± 6.6 months, only four patients have required further maintenance sessions beyond 6 months after completing the induction therapy. The efficacy, speed, tolerability, and more favorable schedule of an EPH program facilitate treatment of HH. J. Clin. Apheresis 17:88–92, 2002. © 2002 Wiley‐Liss, Inc.
Contribution of HDL‐apolipoproteins to the inhibition of low density lipoprotein oxidation and lipid accumulation in macrophages
Authors: Lin Kae‐Yuan , Chen Yuh‐Lien , Shih Chun‐Che , Pan Ju‐Pin , Chan Woan‐Eng , Chiang An‐Na 
Published: October 2002

AbstractHigh‐density lipoprotein (HDL) is known as a protective factor against atherosclerosis. However, whether HDL‐apolipoproteins (apo‐HDL) contribute to the protection in arterial cells remains unclear. The localization patterns of human apolipoproteins in atherosclerotic arteries were determined using immunohistochemical examination. The results indicate that several apolipoproteins are retained in component cells of the coronary artery walls. To elucidate the possible roles of apo‐HDL in the protection of atherosclerotic lesion formation, we investigated the effects of apo‐HDL on the formation of conjugated diene (CD) in a cell‐free system and thiobarbituric acid‐reactive substances (TBARS) in the medium of a macrophage‐mediated LDL oxidation system. The results showed that apo‐HDL significantly exerted an inhibitory effect on LDL lipid oxidation in vitro. In addition, apo‐HDL decreased cholesterol influx but enhanced cholesterol efflux from J774 macrophages in a dose‐dependent manner. These results are consistent with the notion that there is reduced intracellular lipid accumulation in apo‐HDL treated macrophages. These data provide a direct evidence for apo‐HDL in protecting LDL from oxidative modification and in reducing the accumulation of cholesterol and lipid droplets by J774 macrophages. J. Cell. Biochem. 86: 258–267, 2002. © 2002 Wiley‐Liss, Inc.
Characterization of stably transfected fusion protein GFP‐estrogen receptor‐α in MCF‐7 human breast cancer cells
Authors: Zhao Helen , Hart Laura L. , Keller Ulrike , Holth Laurel T. , Davie James R. 
Published: October 2002

AbstractTagging hormone receptors with the green fluorescent protein (GFP) has increased our knowledge of ligand dependent sub‐cellular trafficking of hormone receptors. However, the effect of the tagged hormone receptor expression on the corresponding wild type hormone receptor and endogenous gene expression has not been investigated. In this study, we constructed a MCF‐7 cell line stably expressing GFP‐tagged human estrogen receptor‐α (ER) under control of the tetracycline‐on system to determine the effect of GFP‐ER expression on cell proliferation and expression of endogenous ER and hormone‐responsive genes. Further, the inducible system was applied to determine the ligand dependent turnover rates of GFP‐ER protein and mRNA. Our results demonstrate that GFP‐ER expression did not affect cell cycling. Independent of ligand, GFP‐ER markedly reduced the level of endogenous ER mRNA and protein, suggesting that ER negatively autoregulates its expression. Cisplatin cross‐linking studies showed that GFP‐ER is associated with nuclear DNA in situ, suggesting that GFP‐ER is partially replacing ER at estrogen response elements. Furthermore, GFP‐ER expression did not affect the estradiol induced temporal expression of hormone responsive genes c‐myc and pS2. J. Cell. Biochem. 86: 365–375, 2002. © 2002 Wiley‐Liss, Inc.
A novel mechanism for the regulation of osteoblast differentiation: Transcription of periostin, a member of the fasciclin I family, is regulated by the bHLH transcription factor, twist
Authors: Oshima Akira , Tanabe Hideyuki , Yan Tao , Lowe Gina N. , Glackin Carlotta A. , Kudo Akira 
Published: October 2002

AbstractPeriostin is a secreted protein that is highly expressed in early osteoblastic cells in vitro and in periosteum and periodontal ligament tissues in vivo. It is known that periostin supports cellular adhesion and spreading in vitro. Although, the mechanisms of transcriptional regulation of periostin are poorly understood, gene‐profiling data have revealed that overexpression of Twist, a basic helix‐loop‐helix (bHLH) transcription factor, resulted in increased periostin expression as validated by Northern blot and reverse transcription‐polymerase chain reaction (RT‐PCR) analyses. Twist is an important transcription factor for cell type determination and differentiation and has been shown to play an important regulatory role in early osteogenesis. In situ hybridization of mouse calvarial bones indicated that periostin and Twist mRNA are co‐localized at the osteogenic fronts of calvarial bones. To characterize the 5′ flanking region of the periostin gene, primer extension was carried out to identify the transcription start site, and DNA sequence analysis confirmed the presence of a ‘Twist‐box’ response element. The results of electrophoretic mobility shift assay (EMSA) using nuclear extracts of MC3T3‐E1 cells revealed that Twist bound to the Twist‐box sequence on the periostin promoter. In vivo footprinting experiments using ligation‐mediated PCR (LM‐PCR) indicated that the Twist‐box sequence was protected in undifferentiated MC3T3‐E1 preosteoblasts but not in differentiated MC3T3‐E1 osteoblasts. To determine whether Twist actually regulates the periostin expression, 293T cells were transiently co‐transfected with the periostin promoter construct and the human Twist expression vector. Reporter analysis indicated that the periostin promoter activities were enhanced by overexpression of Twist. These data suggest that Twist can bind to the periostin promoter in undifferentiated preosteoblasts and up‐regulate periostin expression, consistent with the up‐regulation of periostin expression by Twist as observed in the gene‐profiling data. J. Cell. Biochem. 86: 792–804, 2002. © 2002 Wiley‐Liss, Inc.
Gravitational smoothing as a global optimization strategy
Authors: Whitfield T. W. , Straub John E. 
Published: October 2002

AbstractAn optimization scheme for atomic cluster structures, based on exaggerating the importance of the gravitational force, is introduced. Results are presented for calculations on Lennard‐Jones clusters of 13, 38, and 55 atoms, and the 13‐atom Morse cluster. © 2002 Wiley Periodicals, Inc. J Comput Chem 11: 1100–1103, 2002
Stable conformations of 12‐crown‐O3N and its Li+ complex in aqueous solution
Authors: Hori Kenzi , Dou Nobumitsu , Okano Katsuhiko , Ohgami Ai , Tsukube Hiroshi 
Published: October 2002

AbstractStable conformations of 12‐crown‐O3N and its Li complexes in aqueous solution were investigated. To calculate the free energy differences of conformers of 12‐crown‐O3N and its Li+ complex, our procedure was to make use of two programs, CONFLEX and BOSS. The former generates conformers, and the latter calculates the differences in free energy of solvation between two conformers in aqueous solution. It was confirmed that the present procedure is applicable in solving the question of what is the most stable conformation of 12‐crown‐O3N in aqueous solution. Results of the calculations suggest that the order of stability for conformers in a vacuum is different from that in aqueous solution. It was also confirmed that the coordination geometry of solvent waters to Li+ changes depending on the distance between the cation and the crown ring. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1226–1235, 2002
Prediction of aqueous solubility of drugs and pesticides with COSMO‐RS
Authors: Klamt Andreas , Eckert Frank , Hornig Martin , Beck Michael E. , Bürger Thorsten 
Published: October 2002

AbstractThe COSMO‐RS method, originally developed for the prediction of liquid–liquid and liquid–vapor equilibrium constants based on quantum chemical calculations, has been extended to solid compounds by addition of a heuristic expression for the Gibbs free energy of fusion. By this addition, COSMO‐RS is now capable of a priori prediction of aqueous solubilities of a wide range of typical neutral drug and pesticide compounds. Only three parameters in the heuristic expression have been fitted on a data set of 150 drug‐like compounds. On these data an rms deviation of 0.66 log‐units was achieved. Later, the model was tested on a set of 107 pesticides, which have been critically selected based on two experimental data sources and by a crosscheck with an independent HQSAR model. On this data set an rms of 0.61 log‐units was achieved, without any adjustments to the structurally extremely diverse pesticides. This result verifies the ability of this extended COSMO‐RS to predict aqueous solubilities of drugs and pesticides of almost arbitrary structural classes. The new method is COSMO‐RSol. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 275–281, 2002
Childhood antecedents of adult sense of belonging
Authors: Hagerty Bonnie M. , Williams Reg Arthur , Oe Hiroaki 
Published: October 2002

AbstractSense of belonging has been proposed to be a basic human need, and deficits in sense of belonging have been linked to problems in social and psychological functioning. Yet, there is little evidence about what early life experiences contribute to sense of belonging. The purpose of this study was to examine potential childhood antecedents of adult sense of belonging. The sample consisted of 362 community college students ranging in age from 18 to 72 years, with a mean age of 26 years. Measures included the Sense of Belonging Instrument, the Parental Bonding Instrument, and the Childhood Adversity and Adolescent Deviance Instrument. Multiple regression analysis was used to correlate childhood antecedents with adult sense of belonging. The final reduced model included 12 variables, which accounted for 25% of the variance in sense of belonging. Significant positive antecedents with a relationship with sense of belonging were perceived caring by both mother and father while growing up, participation in high school athletic activity, and parental divorce. Significant negative variables with a relationship with sense of belonging included perceived overprotection of father, high school pregnancy, family financial problems while growing up, incest, and homosexuality. Knowledge of these factors should influence interventions with families regarding child‐rearing and parenting practices, mediating the effects of crises during childhood such as divorce and teen pregnancy, and the interpersonal growth needs of teenagers. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 793‐801, 2002.