bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ceramic/polymer nanocomposites with tunable drug delivery capability at specific disease sites
Authors: Liu Huinan , Webster Thomas J. 
Published: September 2009

AbstractPharmaceutical agents are often used to stimulate new bone formation for the treatment of bone injuries or diseases (such as osteoporosis). However, there are several problems associated with current orthopedic drug delivery methods. First, conventional systemic administration of pharmaceutical agents may not effectively reach targeted sites and, thus, they can cause nonspecific bone formation in areas not affected by injury or disease. Second, even if intentionally delivered or implanted locally to the damaged bone tissue, these agents tend to rapidly diffuse into adjacent tissues due to weak physical bonding to their drug carriers, which limits their potential to promote prolonged bone formation in targeted areas of bone disease. Therefore, in this study, biodegradable ceramic/polymer nanocomposites were explored as novel drug carriers for orthopedic applications to prolong local drug release and, thus, improve drug effectiveness at bone disease sites. Specifically, a bone morphogenetic protein (BMP‐7) derived peptide (DIF‐7c) was used as a model drug in this study and was first loaded onto nanocrystalline hydroxyapatite (nano‐HA) by either covalent chemical attachment or physical adsorption. These drug‐carrying nano‐HA particles were then dispersed into a degradable polymer (poly‐lactide‐co‐glycolide or PLGA) matrix to create an implantable system capable of long‐term drug release. The aminophase silane covalent chemical immobilization process was utilized in this study. These nanocomposite‐based drug delivery systems were then characterized for drug loading efficiency andin vitrodrug release. Results demonstrated that DIF‐7c was successfully immobilized onto nano‐HA placed in PLGA. Moreover, a greater prolonged two‐phase release profile (of more than 3 months) was achieved when using aminophase silane chemical immobilization to nano‐HA particles. Since previous studies have demonstrated greaterin vivobone growth on nano‐ compared with micron‐HA particles placed in rat calvaria, this study continued to demonstrate that ceramic/polymer nanocomposites are promising candidates as novel orthopedic materials to promote bone regeneration. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Functionalization of chitosan/poly(lactic acid‐glycolic acid) sintered microsphere scaffolds via surface heparinization for bone tissue engineering
Authors: Jiang Tao , Khan Yusuf , Nair Lakshmi S. , Abdel‐Fattah Wafa I. , Laurencin Cato T. 
Published: September 2009

AbstractScaffolds exhibiting biological recognition and specificity play an important role in tissue engineering and regenerative medicine. The bioactivity of scaffolds in turn influences, directs, or manipulates cellular responses. In this study, chitosan/poly(lactic acid‐co‐glycolic acid) (chitosan/PLAGA) sintered microsphere scaffolds were functionalized via heparin immobilization. Heparin was successfully immobilized on chitosan/PLAGA scaffolds with controllable loading efficiency. Mechanical testing showed that heparinization of chitosan/PLAGA scaffolds did not significantly alter the mechanical properties and porous structures. In addition, the heparinized chitosan/PLAGA scaffolds possessed a compressive modulus of 403.98 ± 19.53 MPa and a compressive strength of 9.83 ± 0.94 MPa, which are in the range of human trabecular bone. Furthermore, the heparinized chitosan/PLAGA scaffolds had an interconnected porous structure with a total pore volume of 30.93 ± 0.90% and a median pore size of 172.33 ± 5.89 μm. The effect of immobilized heparin on osteoblast‐like MC3T3‐E1 cell growth was investigated. MC3T3‐E1 cells proliferated three dimensionally throughout the porous structure of the scaffolds. Heparinized chitosan/PLAGA scaffolds with low heparin loading (1.7 μg/scaffold) were shown to be capable of stimulating MC3T3‐E1 cell proliferation by MTS assay and cell differentiation as evidenced by elevated osteocalcin expression when compared with nonheparinized chitosan/PLAGA scaffold and chitosan/PLAGA scaffold with high heparin loading (14.1 μg/scaffold). This study demonstrated the potential of functionalizing chitosan/PLAGA scaffolds via heparinization with improved cell functions for bone tissue engineering applications. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Stable subclones of the chondrogenic murine cell line MC615 mimic distinct stages of chondrocyte differentiation
Authors: Surmann‐Schmitt Cordula , Widmann Nathalie , Mallein‐Gerin Frédéric , von der Mark Klaus , Stock Michael 
Published: September 2009

AbstractFourteen stable subclones derived from the murine chondrogenic cell line MC615 were established and characterised regarding their differentiation stages and responsivity to BMP2. Based on their gene expression profiles which revealed remarkable variances in Col2a1 and Col10a1 expression, subclones could be grouped into at least three distinct categories. Three representative subclones (4C3, 4C6 and 4H4) were further characterised with respect to gene expression pattern and differentiation capacity. These subclones resembled (i) weakly differentiated chondrogenic precursors, strongly responding to BMP2 stimulation (4C3), (ii) collagen II expressing chondrocytes which could be induced to undergo maturation (4C6) and (iii) mature chondrocytes expressing Col10a1 and other markers of hypertrophy (4H4). Interestingly, BMP2 administration caused Smad protein phosphorylation and stimulated Col10a1 expression in all clones, but induced Col2a1 expression only in precursor‐like cells. Most remarkably, these clones maintained a stable gene expression profile at least until the 30th passage of subconfluent culture, but revealed reproducible changes in gene expression and differentiation pattern in long term high density cultures. Thus, the newly established MC615 subclones may serve as a potent new tool for investigations on the regulation of chondrocyte differentiation and function. J. Cell. Biochem. 108: 589–599, 2009. © 2009 Wiley‐Liss, Inc.
JNK1/c‐Jun and p38α MAPK/ATF‐2 pathways are responsible for upregulation of Fas/FasL in human chronic myeloid leukemia K562 cells upon exposure to Taiwan cobra phospholipase A2
Authors: Chen Ku‐Chung , Chiou Yi‐Ling , Chang Long‐Sen 
Published: September 2009

AbstractFas and FasL expression upregulation was found in human leukemia K562 cells upon exposure to Naja naja atra phospholipase A2 (PLA2). PLA2 treatment induced an increase in intracellular Ca2+ ([Ca2+]i) and ROS generation levels, leading to activation of p38 MAPK and JNK. Suppression of both p38 MAPK and JNK abrogated Fas and FasL upregulation. Unlike PLA2, catalytically inactive PLA2 treatment did not markedly increase Fas and FasL protein expression, and p38 MAPK activation was exclusively responsible for catalytically inactive PLA2‐induced increase in Fas and FasL protein expression. Knockdown of p38α MAPK and JNK1 by siRNA proved that p38α MAPK and JNK1 were involved in ATF‐2 and c‐Jun phosphorylation, respectively. Compared with the p38α MAPK/ATF‐2 pathway, the JNK1/c‐Jun pathway played a crucial role in Fas/FasL upregulation. Unlike arachidonic acid, lysophosphatidylcholine mimicked the PLA2 action in inducing Fas/FasL upregulation. Together with the previous finding that c‐Jun and ATF‐2 are involved in transcriptional regulation of Fas and FasL, our data suggest that PLA2 induces Fas and FasL upregulation through p38α MAPK/ATF‐2 and JNK1/c‐Jun pathways in K562 cells, and PLA2 catalytic activity is involved in this action. J. Cell. Biochem. 108: 612–620, 2009. © 2009 Wiley‐Liss, Inc.
Neuropeptide Y is expressed by osteocytes and can inhibit osteoblastic activity
Authors: Igwe John C. , Jiang Xi , Paic Frane , Ma Li , Adams Douglas J. , Baldock Paul A. , Pilbeam Carol C. , Kalajzic Ivo 
Published: September 2009

AbstractOsteocytes are the most abundant osteoblast lineage cells within the bone matrix. They respond to mechanical stimulation and can participate in the release of regulatory proteins that can modulate the activity of other bone cells. We hypothesize that neuropeptide Y (NPY), a neurotransmitter with regulatory functions in bone formation, is produced by osteocytes and can affect osteoblast activity. To study the expression of NPY by the osteoblast lineage cells, we utilized transgenic mouse models in which we can identify and isolate populations of osteoblasts and osteocytes. The Col2.3GFP transgene is active in osteoblasts and osteocytes, while the DMP1 promoter drives green fluorescent protein (GFP) expression in osteocytes. Real‐time PCR analysis of RNA from the isolated populations of cells derived from neonatal calvaria showed higher NPY mRNA in the preosteocytes/osteocytes fraction compared to osteoblasts. NPY immunostaining confirmed the strong expression of NPY in osteocytes (DMP1GFP+), and lower levels in osteoblasts. In addition, the presence of NPY receptor Y1 mRNA was detected in cavaria and long bone, as well as in primary calvarial osteoblast cultures, whereas Y2 mRNA was restricted to the brain. Furthermore, NPY expression was reduced by 30–40% in primary calvarial cultures when subjected to fluid shear stress. In addition, treatment of mouse calvarial osteoblasts with exogenous NPY showed a reduction in the levels of intracellular cAMP and markers of osteoblast differentiation (osteocalcin, BSP, and DMP1). These results highlight the potential regulation of osteoblast lineage differentiation by local NPY signaling. J. Cell. Biochem. 108: 621–630, 2009. © 2009 Wiley‐Liss, Inc.
ERK‐1 MAP kinase prevents TNF‐induced apoptosis through bad phosphorylation and inhibition of Bax translocation in HeLa Cells
Authors: Pucci Bruna , Indelicato Manuela , Paradisi Valentina , Reali Valentina , Pellegrini Laura , Aventaggiato Michele , Karpinich Natalie O. , Fini Massimo , Russo Matteo A. , Farber John L. , Tafani Marco 
Published: September 2009

AbstractExtracellular signal‐regulated kinase (ERK) 1/2 signaling is involved in tumor cell survival through the regulation of Bcl‐2 family members. To explore this further and to demonstrate the central role of the mitochondria in the ERK1/2 pathway we used the HeLa cellular model where apoptosis was induced by tumor necrosis factor (TNF) and cycloheximide (CHX). We show that HeLa cells overexpressing ERK‐1 displayed resistance to TNF and CHX. HeLa cells overexpressing a kinase‐deficient form of ERK‐1 (K71R) were more sensitive to TNF and CHX. In the ERK‐1 cells, Bad was phosphorylated during TNF + CHX treatment. In the HeLa wt cells and in the K71R clones TNF and CHX decreased Bad phosphorylation. ERK‐1 cells treated with TNF and CHX did not release cytochrome c from the mitochondria. By contrast, HeLa wt and K71R clones released cytochrome c. Bax did not translocate to the mitochondria in ERK‐1 cells treated with TNF + CHX. Conversely, HeLa wt and K71R clones accumulated Bax in the mitochondria. In the HeLa wt cells and in both ERK‐1 transfectants Bid was cleaved and accumulated in the mitochondria. The caspase‐8 inhibitor IETD‐FMK and the mitochondrial membrane permeabilization inhibitor bongkrekic acid (BK), partially prevented cell death by TNF + CHX. Anisomycin, a c‐Jun N‐terminal kinases activator, increased TNF‐killing. The ERK‐1 cells were resistant to TNF and anisomycin, whereas K71R clones resulted more sensitive. Our study demonstrates that in HeLa cells the ERK‐1 kinase prevents TNF + CHX apoptosis by regulating the intrinsic mitochondrial pathway through different mechanisms. Inhibition of the intrinsic pathway is sufficient to almost completely prevent cell death. J. Cell. Biochem. 108: 1166–1174, 2009. © 2009 Wiley‐Liss, Inc.
Lanthanum suppresses osteoblastic differentiation via pertussis toxin‐sensitive G protein signaling in rat vascular smooth muscle cells
Authors: Shi Yan‐Ling , Wang Li‐Wen , Huang Jian , Gou Bao‐Di , Zhang Tian‐Lan , Wang Kui 
Published: September 2009

AbstractA major cellular event in vascular calcification is the phenotypic transformation of vascular smooth muscle cells (VSMCs) into osteoblast‐like cells. After demonstrating that lanthanum chloride (LaCl3) suppresses hydrogen peroxide‐enhanced calcification in rat calcifying vascular cells (CVCs), here we report its effect on the osteoblastic differentiation of rat VSMCs, a process leading to the formation of CVCs. Cells were isolated from aortic media of male SD rats, and passages between three and eight were cultured in Dulbeccol's Modified Eagle's Medium (DMEM) containing 10% fetal bovine serum (FBS) and 10 mM β‐glycerophosphate (β‐GP) in the presence or absence of LaCl3. Exposure of cells to LaCl3 suppressed the β‐GP‐induced elevations in calcium deposition, alkaline phosphatase (ALP) activity, and Cbfa1/Runx2 expression, as well as the concomitant loss of SM α‐actin. Furthermore, LaCl3 activated the phosphorylation of extracellular signal‐regulated kinase (ERK) and c‐Jun N‐terminal kinase (JNK), and the blockage of either pathway with a specific inhibitor abolished the effects of LaCl3. In addition, pretreatment of the cells with pertussis toxin (PTx), an inhibitor of G protein‐mediated signaling pathway, repealed all the changes induced by LaCl3. These findings demonstrate that LaCl3 suppresses the β‐GP‐induced osteoblastic differentiation and calcification in rat VSMCs, and its effect is mediated by the activation of both ERK and JNK MAPK pathways via PTx‐sensitive G proteins. J. Cell. Biochem. 108: 1184–1191, 2009. © 2009 Wiley‐Liss, Inc.
Evaluation of exchange‐correlation functionals for time‐dependent density functional theory calculations on metal complexes
Authors: Holland Jason P. , Green Jennifer C. 
Published: September 2009

AbstractThe electronic absorption spectra of a range of copper and zinc complexes have been simulated by using time‐dependent density functional theory (TD‐DFT) calculations implemented in Gaussian03. In total, 41 exchange‐correlation (XC) functionals including first‐, second‐, and third‐generation (meta‐generalized gradient approximation) DFT methods were compared in their ability to predict the experimental electronic absorption spectra. Both pure and hybrid DFT methods were tested and differences between restricted and unrestricted calculations were also investigated by comparison of analogous neutral zinc(II) and copper(II) complexes. TD‐DFT calculated spectra were optimized with respect to the experimental electronic absorption spectra by use of a Matlab script. Direct comparison of the performance of each XC functional was achieved both qualitatively and quantitatively by comparison of optimized half‐band widths, root‐mean‐squared errors (RMSE), energy scaling factors (εSF), and overall quality‐of‐fit (QF) parameters. Hybrid DFT methods were found to outperform all pure DFT functionals with B1LYP, B97‐2, B97‐1, X3LYP, and B98 functionals providing the highest quantitative and qualitative accuracy in both restricted and unrestricted systems. Of the functionals tested, B1LYP gave the most accurate results with both average RMSE and overall QF < 3.5% and εSF values close to unity (>0.990) for the copper complexes. The XC functional performance in spin‐restricted TD‐DFT calculations on the zinc complexes was found to be slightly worse. PBE1PBE, mPW1PW91 and B1LYP gave the most accurate results with typical RMSE and QF values between 5.3 and 7.3%, and εSF around 0.930. These studies illustrate the power of modern TD‐DFT calculations for exploring excited state transitions of metal complexes. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Engineering adeno‐associated virus serotype 2‐based targeting vectors using a new insertion site‐position 453‐and single point mutations
Authors: Boucas Jorge , Lux Kerstin , Huber Anke , Schievenbusch Stephanie , von Freyend Miriam John , Perabo Luca , Quadt‐Humme Sibille , Odenthal Margarete , Hallek Michael , Büning Hildegard 
Published: September 2009

AbstractBackgroundGenetic modification of capsid proteins by peptide insertion has created the possibility of using adeno‐associated viral (AAV) vectors for receptor specific gene transfer (AAV targeting). The most common site used for insertion in AAV serotype 2 capsids are amino acid positions 587 and 588 located at the second highest capsid protrusion. Reasoning that peptide insertions at the most exposed position augments target receptor interaction, we explored position 453 as a new insertion site.MethodsPosition 453 was identified in silico. Capsid mutants carrying the model ligand RGD‐4C in position 453 with and without R585A/R588A substitutions were compared with respective mutants carrying the ligand in position 587. The accessibility of the inserted ligand was determined by an enzyme‐linked immunosorbent assay, whereas the transduction efficiency and specificity of receptor binding were assayed by gene transfer and competition experiments, respectively. Vector biodistribution was determined in mice by quantitative polymerase chain reaction analysis.ResultsInitially, RGD‐4C, inserted at position 453, failed to efficiently bind its target receptor. R585 and R588, located at the neighboring peak and known to mediate primary receptor binding, were identified as interfering residues. R585A and R588A substitutions rendered position 453 mutants superior to those with the ligand in position 587 in target receptor binding and cell transduction efficiency. The in vivo biodistribution was independent of the insertion site, but directed by the inserted ligand when primary receptor binding was avoided.ConclusionsPosition 453 emerged as a prominent site for the development of targeting mutants. Furthermore, we show for the first time that linearly distant residues can be critical for the efficiency of inserted peptide ligands. Copyright © 2009 John Wiley & Sons, Ltd.
Identification and spectra–structure determination of soil minerals: Raman study supported by IR spectroscopy and X‐ray powder diffraction
Authors: Tomić Zorica , Makreski Petre , Gajić Boško 
Published: September 2009

AbstractRaman and IR spectroscopy were used for the characterization of several minerals in morphologically similar vertisol sequences from Kiževak (Serbia). It helped us to establish the surface layer transition going from calcic vertisols (containing gypsum and calcite) to calcimagnesic vertisols (containing aragonite, magnesium‐calcite and dolomite) derived from peridotite and serpentinite. The observed band positions are found to be solely characteristic for each carbonate mineral and are used to discuss the main structural features of carbonates and sulfates present in the studied soil. It was found that the dolomite, calcite and aragonite concretions are present in the deepest layer of the soil, whereas the gypsum is found in the topsoil. The identification was confirmed of the carbonates having calcite and aragonite structure, and the representative from the sulfate group (gypsum) was confirmed by X‐ray powder diffraction. Copyright © 2009 John Wiley & Sons, Ltd.
Probing the adsorption of methylimidazole at ionic liquids/Cu electrode interface by surface‐enhanced Raman scattering spectroscopy
Authors: Yuan Ya‐Xian , Niu Tian‐Chao , Xu Min‐Min , Yao Jian‐Lin , Gu Ren‐Ao 
Published: September 2009

AbstractTwo kinds of room‐temperature ionic liquids, 1‐butyl‐3‐methylimidazolium bromide ([BMIM]Br) and 1‐butyl‐3‐methylimidazolium tetrafluoroboride ([BMIM]BF4), were used as solvent, and the adsorption of the ionic liquids themselves and of N‐methylimidazole (NMIM) were investigated by electrochemical surface‐enhanced Raman scattering (SERS) over a wide potential window. The results revealed that the cation of ionic liquid adsorbed onto Cu surface with different configurations in different potential ranges. When the potential was changed from the negative to the positive range, the orientation underwent a change from flat to vertical, and the onset potential for the orientation change was dependent on the types of anion of the ionic liquid. The ionic liquid in bulk solution exhibited a remarkable effect on the adsorption of NMIM. The electrode surface structure changed from adsorbing the ionic liquid at the negative potential to coadsorbing the ionic liquid and NMIM at relative positive potential for the [BMIM]BF4 liquids, and formed films of NMIM at extremely positive potential. Due to the strong specific adsorption of Br−, the coadsorption of ionic liquid and NMIM was not observed in the system [BMIM]Br. By simulating the electrode surroundings, two surface complexes [Cu(NMIM)4Br]Br·H2O and [Cu(NMIM)4](BF4)2 were synthesized by the electrochemical method in the corresponding ionic liquids for modeling the surface coordination chemistry of NMIM. The surface coordination configuration of NMIM and ionic liquids is proposed. Copyright © 2009 John Wiley & Sons, Ltd.
Expression of X‐linked inhibitor of apoptosis protein in human colorectal cancer and its correlation with prognosis
Authors: Guoan Xiang , Xiaomin Wen , Hanning Wang , Kaiyun Chen , Hao Liu 
Published: September 2009

AbstractBackgroundX‐linked inhibitor of apoptosis protein (XIAP) is a member of the inhibitor of apoptosis family of proteins and deregulation of XIAP can result in tumorigenicity. The objective of this study was to evaluate the prognostic significance of XIAP expression in colorectal cancer (CRC).MethodsRT‐PCR was performed to detect the expression of XIAP mRNA in CRC cells and tissues. The expression of XIAP protein in tissues was measured by immunohistochemistry. The correlation of XIAP expression with clinicopathologic factors and prognosis of CRC patients was evaluated.ResultsCRC cells showed significantly higher levels of XIAP mRNA expression than normal human intestinal epithelial cell. The expression level of XIAP mRNA in CRC samples was significantly higher than that in corresponding non‐tumor samples. XIAP staining was positive in the cytoplasm of CRC cells. Higher XIAP protein expression was significantly correlated with tumor differentiation (P = 0.016), venous invasion (P = 0.039), and Duke's staging (P = 0.002). Moreover, XIAP‐high group showed lower disease‐free (P = 0.0136) and overall survival (P = 0.0084) rates than XIAP‐low group. Multivariate analysis indicated that the status of XIAP expression was an independent prognostic factor for CRC (P = 0.0206; HR: 2.730; 95% CI: 1.226–5.445).ConclusionThe status of XIAP expression might become an independent prognostic marker for CRC. J. Surg. Oncol. 2009;100:708–712. © 2009 Wiley‐Liss, Inc.
Dispersion‐solidification liquid–liquid microextraction for volatile aromatic hydrocarbons determination: Comparison with liquid phase microextraction based on the solidification of a floating drop
Authors: Vickackaite Vida , Pusvaskiene Edita 
Published: September 2009

AbstractTwo microextraction techniques – liquid phase microextraction based on solidification of a floating organic drop (LPME‐SFO) and dispersive liquid–liquid microextraction combined with a solidification of a floating organic drop (DLLME‐SFO) – are explored for benzene, toluene, ethylbenzene and o‐xylene sampling and preconcentration. The investigation covers the effects of extraction solvent type, extraction and disperser solvents' volume, and the extraction time. For both techniques 1‐undecanol containing n‐heptane as internal standard was used as an extracting solvent. For DLLME‐SFO acetone was used as a disperser solvent. The calibration curves for both techniques and for all the analytes were linear up to 10 μg/mL, correlation coefficients were in the range 0.997–0.998, enrichment factors were from 87 for benzene to 290 for o‐xylene, detection limits were from 0.31 and 0.35 μg/L for benzene to 0.15 and 0.10 μg/L for o‐xylene for LPME‐SFO and DLLME‐SFO, respectively. Repeatabilities of the results were acceptable with RSDs up to 12%. Being comparable with LPME‐SFO in the analytical characteristics, DLLME‐SFO is superior to LPME‐SFO in the extraction time. A possibility to apply the proposed techniques for volatile aromatic hydrocarbons determination in tap water and snow was demonstrated.