bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oriented Attachment Growth of Three‐Dimensionally Packed Trigonal Selenium Microspheres into Large‐Area Wire Networks
Authors: Yang Liangbao , Shen Yuhua , Xie Anjian , Liang Jianjun 
Published: August 2007

AbstractThe formation of Se microwire networks by hydrothermal treatment in tungstosilicic acid solution is described. The kinetics of crystallization of the Se assembly is studied as a function of reaction time. During the formation process, single‐crystal Se rods can direct the self‐aggregation of the amorphous nanoparticles derived from a supersaturation precipitation reaction and promote their crystallization and transformation under mild hydrothermal conditions. In this system, the rod‐directed epitaxial aggregation of Se was clearly observed in addition to the traditional Ostwald ripening process.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Treatment with amisulpride and olanzapine improve neuropsychological function in schizophrenia
Authors: Mortimer Ann M. , Joyce Eileen , Balasubramaniam Krishnapillai , Choudhary Prasoon C. , Saleem Packeeruther T. 
Published: August 2007

AbstractObjectivesAlthough antipsychotic drugs control acute psychotic manifestations of schizophrenia, improving cognitive symptoms is also important for long‐term prognosis.MethodsThree hundred and seventy‐seven adult patients with acute psychosis were randomised to either amisulpride (200–800 mg/d) or olanzapine (5–20 mg/d) for 6 months. Neuropsychological performance was assessed at inclusion and after 6 months in a subgroup of 26 subjects (11 treated with amisulpride and 15 with olanzapine) using the Auditory Verbal Learning Test (AVLT), the Trail Making Test (TMT) and the Controlled Oral Word Association Test (COWAT).ResultsThe improvement in BPRS score was similar in both treatment groups. No significant differences in test performance between groups were observed at inclusion. After 6 months, AVLT scores increased by 8.7 points in the amisulpride group and by 2.3 points in the olanzapine group (p = 0.049). Completion speed in the TMT increased by 17.4 s (amisulpride) and 15.4 s (olanzapine) for Part A and by 39.8 and 48.8 s, respectively for Part B. Performance in the COWAT improved little in both groups.ConclusionsBoth amisulpride and olanzapine produce sustained improvement in certain measures of neuropsychological performance in patients with schizophrenia; a significant improvement in score on the AVLT was observed only with amisulpride. Copyright © 2007 John Wiley & Sons, Ltd.
Variants of chemokine receptor 2 and interleukin 4 receptor, but not interleukin 10 or Fas ligand, increase risk of cervical cancer
Authors: Ivansson Emma L. , Gustavsson Inger M. , Magnusson Jessica J. , Steiner Lori L. , Magnusson Patrik K.E. , Erlich Henry A. , Gyllensten Ulf B. 
Published: August 2007

AbstractCervical cancer is caused by persistent infection of oncogenic human papillomavirus (HPV). Most infected women clear the virus without developing cervical lesions and it is likely that immunological host factors affect susceptibility to cervical cancer. The impact of the human leukocyte antigen (HLA) locus on the risk of cervical cancer is established and several other genes involved in immunological pathways have been suggested as biologically plausible candidates. The aim of this study was to examine the potential role of polymorphisms in 4 candidate genes by analysis of 1,306 familial cervical cancer cases and 288 controls. The following genes and polymorphisms were studied: Chemokine receptor 2 (CCR‐2) V64I; Interleukin 4 receptor α (IL‐4R) I75V, S503P and Q576R; Interleukin 10 (IL‐10) −592; and Fas ligand (FasL) −844. The CCR‐2 64I variant was associated with decreased risk of cervical cancer; homozygote carriers of the 64I variant had an odds ratio of 0.31 (0.12–0.77). This association was detected in both carriers and noncarriers of the HLA DQB1*0602 cervical cancer risk allele. The IL‐4R 75V variant was associated with increased risk of cervical tumors, cases homozygote for 75V had an odds ratio of 1.91 (1.27–2.86) with a tendency that the association was stronger in noncarriers of the DQB1*0602 allele. We did not find any association for IL‐10 −592, or FasL −844, previously reported to be associated with cervical cancer in the Dutch and Chinese populations, respectively. © 2007 Wiley‐Liss, Inc.
Identification of a subset of pericytes that respond to combination therapy targeting PDGF and VEGF signaling
Authors: Hasumi Yoko , Kłosowska‐Wardęga Agnieszka , Furuhashi Masao , Östman Arne , Heldin Carl‐Henrik , Hellberg Carina 
Published: August 2007

AbstractThe aim of our study was to further explore the use of anti‐angiogenic therapy targeting the vascular endothelial growth factor receptor (VEGFR) on endothelial cells while simultaneously targeting platelet‐derived growth factor receptors (PDGFRs) on adjacent pericytes. B16 mouse melanoma tumors exogenously expressing PDGF‐BB (B16/PDGF‐BB) display higher pericyte coverage on the vasculature compared to the parental B16 tumors (B16/mock). These models were used to investigate the effects of combination therapy targeting VEGFR and PDGFR signaling on size‐matched tumors. Combination therapy using 25 mg/kg/day of the VEGFR inhibitor PTK787 and 100 mg/kg/day of the PDGFR inhibitor STI571 decreased the tumor growth rate of both tumor types, but the inhibition was only significant in the B16/PDGF‐BB tumors. Combination therapy induced vessel remodeling, primarily by reducing the vessel density in B16/mock tumors, and by reducing the vessel size in B16/PDGF‐BB tumors. When analyzing the effects of combination therapy on tumor vessel pericytes, it was found to primarily reduce the subpopulation of α‐smooth muscle actin and PDGFRβ‐positive pericytes partly detached from the tumor vessels, without affecting the number of pericytes closely attached to the endothelium, which also express desmin. Taken together, these data demonstrate an increased benefit of targeting both VEGFR and PDGFR pathways in B16/PDGF‐BB tumors, and demonstrates that the increased tumor growth inhibition in this model is accompanied by a reduction in a specific subset of pericytes, characterized by being loosely attached to endothelial cells and negative for the pericyte marker desmin. © 2007 Wiley‐Liss, Inc.
Intratumoral homogeneity of MGMT promoter hypermethylation as demonstrated in serial stereotactic specimens from anaplastic astrocytomas and glioblastomas
Authors: Grasbon‐Frodl Eva M. , Kreth Friedrich Wilhelm , Ruiter Michael , Schnell Oliver , Bise Karl , Felsberg Jörg , Reifenberger Guido , Tonn Jörg‐Christian , Kretzschmar Hans A. 
Published: August 2007

AbstractHypermethylation of the DNA repair gene O6‐methyl‐guanine DNA methyltransferase (MGMT) has been linked to prolonged survival in glioblastoma patients treated with alkylating agents. It was aimed to analyze prospectively whether the MGMT status of malignant gliomas could be determined from small‐sized stereotactic biopsies (maximum volume: 1 mm3). Special attention was directed towards the intratumoral distribution of the MGMT promoter methylation, the MGMT protein expression and potential correlations between both. Twenty‐five adult patients were included (20 patients with primary World Health Organisation (WHO) Grade III or IV malignant gliomas, 5 patients with secondary malignant gliomas). About 2–4 biopsy specimens per tumor were collected from different sites within the tumor. Promoter methylation of the MGMT gene was assessed by methylation‐specific PCR (MSP) and sodium bisulfite sequencing in each of the collected specimens (overall number of specimens: 69). Both methods were validated for application in small‐sized tissue samples (1 mm3). The MGMT protein expression was analyzed by immunohistochemistry. The overall MGMT promoter methylation rate was 30% in the de novo group and 80% in the tumor progression group. The success rates of MSP and sequencing were 100% and 80%, respectively. Sequence analysis and MSP exhibited 100% concordant findings. No differences in MGMT promoter methylation were detected between the different samples of each individual tumor in 24 of 25 patients. One false negative result was obtained due to the contamination of the biopsy specimen by necrotic tissue. Tissue samples taken from different sites of each individual tumor (13 tumors investigated) exhibited equal or highly similar MGMT protein expression. No correlation between MGMT protein expression and MGMT promoter methylation was observed. The MGMT promoter methylation status of malignant gliomas can be reliably determined from small‐sized stereotactic biopsies. The methylation profile, as defined by MSP and sodium bisulfite sequencing, constitutes a homogeneous marker throughout malignant gliomas. The lack of correlation between MGMT status and MGMT protein expression needs further evaluation. © 2007 Wiley‐Liss, Inc.
Differential osteogenic activity of osteoprogenitor cells on HA and TCP/HA scaffold of tissue engineered bone
Authors: Ng Angela M.H. , Tan K.K. , Phang M.Y. , Aziyati O. , Tan G.H. , Isa M.R. , Aminuddin B.S. , Naseem M. , Fauziah O. , Ruszymah B.H.I. 
Published: August 2007

AbstractBiomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma‐derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Connective‐tissue responses to defined biomaterial surfaces. II. Behavior of rat and mouse fibroblasts cultured on microgrooved substrates
Authors: Grew John C. , Ricci John L. , Alexander Harold 
Published: August 2007

AbstractSurface microgeometry strongly influences the shapes, orientations, and growth characteristics of cultured cells, but in‐depth, quantitative studies of these effects are lacking. We investigated several contact guidance effects in cells within “dot” colonies of primary fibroblasts and in cultures of a transformed fibroblast cell line, employing titanium‐coated, microgrooved polystyrene surfaces that we designed and produced. The aspect ratios, orientations, densities, and attachment areas of rat tendon fibroblasts (RTF) colony cells, in most cases, varied (p < 0.01) by microgroove dimension. We observed profoundly altered cell morphologies, reduced attachment areas, and reduced cell densities within colonies grown on microgrooved substrates, compared with cells of colonies grown on flat, control surfaces. 3T3 fibroblasts cultured on microgrooved surfaces demonstrated similarly altered morphologies. Fluorescence microscopy revealed that microgrooves alter the distribution and assembly of cytoskeletal and attachment proteins within these cells. These findings are consistent with previous results, and taken together with the results of our in vivo and cell colony growth studies, enable us to propose a unified hypothesis of how microgrooves induce contact guidance. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Connective‐tissue responses to defined biomaterial surfaces. I. Growth of rat fibroblast and bone marrow cell colonies on microgrooved substrates
Authors: Ricci John L. , Grew John C. , Alexander Harold 
Published: August 2007

AbstractSurface microgeometry plays a role in tissue‐implant surface interactions, but our understanding of its effects is incomplete. Substrate microgrooves strongly influence cells in vitro, as evidenced by contact guidance and cell alignment. We studied “dot” colonies of primary fibroblasts and bone marrow cells that were grown on titanium‐coated, microgrooved polystyrene surfaces that we designed and produced. Rat tendon fibroblast and rat bone marrow colony growth and migration varied (p < 0.01) by microgroove dimension and slightly by cell type. We observed profoundly altered morphologies, reduced growth rates, and directional growth in colonies grown on microgrooved substrates, when compared with colonies grown on flat, control surfaces (p < 0.01). The cells in our colonies grown on microgrooved surfaces were well aligned and elongated in the direction parallel to the grooves and colonies. Our “dot” colony is an easily reproduced, easily measured and artificial explant model of tissue‐implant interactions that better approximates in vivo implant responses than culturing isolated cells on biomaterials. Our results correlate well with in vivo studies of titanium dioxide‐coated polystyrene, titanium, and titanium alloy implants with controlled microgeometries. Microgrooves and other surface features appear to directionally or spatially organize cells and matrix molecules in ways that contribute to improved stabilization and osseointegration of implants. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
N‐halamine‐based chitosan: Preparation, characterization, and antimicrobial function
Authors: Cao Zhengbing , Sun Yuyu 
Published: August 2007

AbstractUpon chlorine bleach treatment, amino groups in chitosan were transformed into N‐halamine structures. The transformation was confirmed by UV/VIS, XPS, DSC, and TGA evaluation and iodimetric titration. The N‐halalmine‐based chitosan provided total kill of 108–109 colony forming units (CFU/mL) of E. coli (gram‐negative bacteria) and S. aureus (gram‐positive bacteria) in 10 and 60 min, respectively. SEM observations demonstrated that the chlorinated chitosan effectively prevented the formation of bacterial biofilms. The antimicrobial activity and bio film controlling function were stable for longer than 1 month; when the functions were lost due to extensive use and/or prolonged storage, they could be readily recharged by another bleach treatment. The antimicrobial mechanism was also discussed. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
MicroCT analysis of hydroxyapatite bone repair scaffolds created via three‐dimensional printing for evaluating the effects of scaffold architecture on bone ingrowth
Authors: Simon Joshua L. , Rekow E. Dianne , Thompson Van P. , Beam Heather , Ricci John L. , Parsons J. Russell 
Published: August 2007

AbstractRecent studies have shown that it is now possible to construct tissue‐engineered bone repair scaffolds with tight pore size distributions and controlled geometries using 3‐D Printing techniques (3DP). This study evaluated two hydroxyapatite (HA) 8‐mm diameter discs with controlled architectures in a rabbit trephine defect at 8 and 16 weeks using a 2 × 2 factorial design. Input parameters were time and scaffold void volume at two levels. Three output variables were extracted from MicroCT data: bone volume ingrowth with respect to total region of interest, bone volume ingrowth with respect to available ingrowth volume, and soft tissue volume. The experiment measured two groups—Group 1: 500‐μm × 500‐μm channels parallel to the scaffold's long axis and penetrating up 3‐mm from the bottom. Group 2: 800‐μm × 800‐μm struts spaced 500 μm apart set perpendicularly to each other in each printed layer. Rendered 3‐dimensional MicroCT scans and undecalcified histological slides of implants revealed good integration with the surrounding tissue, and a sizeable amount of bone ingrowth into the device. Factorial analysis revealed that the effects of time were the greatest determinant of soft tissue ingrowth, while time and its interaction with void volume were the greatest determinants of bone volume ingrowth with respect to both total and available volume. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Characterization of Staphylococcus aureus strains in a rabbit model of osseointegrated pin infections
Authors: Williams Dustin , Bloebaum Roy , Petti Cathy A. 
Published: August 2007

AbstractStaphylococcus aureus is a common infecting agent of many surgical sites. As a commensal organism to humans and rabbits, the infection process may occur due to native or exogenous S. aureus. We applied exogenous S. aureus ATCC 49230 once weekly to the surgical site of an osseointegrated pin in 20 New Zealand white rabbits. Clinical signs of infection resulted in euthanasia and at necropsy samples were collected from putatively infected sites. The predominant organism cultured was S. aureus. We observed various β‐hemolysis patterns of S. aureus on culture media and used pulsed field gel electrophoresis (PFGE) to determine whether there were distinct strains of S. aureus collected from various sites of the rabbits. On the basis of PFGE results, we found that the exogenous S. aureus ATCC 49230 was not the S. aureus cultured during necropsy, but that S. aureus native to the rabbits was in fact the infecting agent. We conclude that this rabbit model for S. aureus infection, which has not been described previously, may contribute to understanding the pathogenesis of S. aureus infections in future studies with simulated osseointegrated pin infections secondary to S. aureus. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Differentiation stage alters matrix control of stem cells
Authors: Hsiong Susan X. , Carampin Paolo , Kong Hyun‐Joon , Lee Kuen‐Yong , Mooney David J. 
Published: August 2007

AbstractCues from the material to which a cell is adherent (e.g., adhesion ligand presentation, substrate elastic modulus) clearly influence the phenotype of differentiated cells. However, it is currently unclear if stem cells respond similarly to these cues. This study examined how the overall density and nanoscale organization of a model cell adhesion ligand (arginine‐glycine‐aspartic acid [RGD] containing peptide) presented from hydrogels of varying stiffness regulated the proliferation of a clonally derived stem cell line (D1 cells) and preosteoblasts (MC3T3‐E1). While the growth rate of MC3T3‐E1 preosteoblasts was responsive to nanoscale RGD ligand organization and substrate stiffness, the D1 stem cells were less sensitive to these cues in their uncommitted state. However, once the D1 cells were differentiated towards the osteoblast lineage, they became more responsive to these signals. These results demonstrate that the cell response to material cues is dependent on the stage of cell commitment or differentiation, and these findings will likely impact the design of biomaterials for tissue regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Composites of poly(DL‐lactide‐co‐glycolide) and calcium carbonate: In vitro evaluation for use in orthopedic applications
Authors: Cotton Nicholas J. , Egan Melissa J. , Brunelle John E. 
Published: August 2007

AbstractBiodegradable materials utilized in current orthopedic sports medicine fixation devices are required to maintain mechanical properties for at least 12 weeks to facilitate tissue healing and then ideally degrade with eventual replacement by surrounding tissue (bone). Current materials exhibit excessive longevity, which limit the potential for bone replacement, an ideal outcome in clinical procedures where revisions are a possibility. This study investigates material property modification of poly(DL‐lactide‐co‐glycolide) (PLGA) by calcium carbonate. Modification of the degradation rate of PLGA by calcium carbonate (16, 36, 51% w/w) was demonstrated and the percentage of calcium carbonate within the polymer optimized at 36% (w/w). The optimized formulation was molded into a fixation screw and in vitro degradation demonstrated a gradual loss in molecular weight but with a pull‐out strength retention beyond 12 weeks. Significant mass loss then occurred after 26 weeks. Physical testing, insertion torque, and failure torque indicated that this composite also had sufficient initial mechanical properties required for screw in type fixation devices. The combination of mechanical properties and degradation behavior suggests that this material may have potential to be utilized in orthopedic fixation devices that are placed in bone. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Closing capacity of segmental radius defects in rabbits
Authors: Bodde Esther W.H. , Spauwen Paul H.M. , Mikos Antonios G. , Jansen John A. 
Published: August 2007

AbstractIn the research of synthetic bone graft substitutes, the relevance for bone regeneration can be confirmed in a critical‐sized model. In this study the rabbit radial defect was investigated as an ingenious model of critical size, due to its defect immobilizing intact ulna. In addition, the influence of poly(DL‐lactic‐co‐glycolic acid) (PLGA) on bone regeneration was determined. Sixteen, 4‐month‐old rabbits received bilateral segmental radial defects of 15 or 20 mm. The osteotomy ends were marked with small titanium pins. Half of the group received injected PLGA microparticle/carboxymethylcellulose implants. Implantation time was 12 weeks. Evaluation consisted of radiographs after surgery and sacrifice, microcomputed tomography and histology. The radiographs revealed that the created defects were significantly smaller after sacrifice. Further a number of radii showed fibrocartilaginous interposition. Both findings indicated instability of the created defect. All evaluation techniques revealed that 15 and 20 mm were not of critical size, as most defects were more or less regenerated. PLGA microparticles did not influence bone regeneration significantly. In conclusion, 15‐ and 20‐mm radius defects in 4‐month‐old rabbits were not a suitable model for bone regeneration as these defects were neither critical size nor stable. PLGA‐microparticle degradation did not influence bone regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Enhanced osteoblast functions on anodized titanium with nanotube‐like structures
Authors: Yao Chang , Slamovich Elliott B. , Webster Thomas J. 
Published: August 2007

AbstractPrevious studies have demonstrated increased osteoblast (bone‐forming cells) adhesion on titanium and Ti‐6Al‐4V anodized to possess nanometer features compared with their unanodized counterparts. In this study, osteoblast long‐term functions (specifically, synthesis of intracellular proteins, synthesis of intracellular collagen, alkaline phosphatase activity, and deposition of calcium‐containing minerals) were determined on titanium anodized to possess either heterogeneous nanoparticles or ordered nanotubes. Titanium was anodized in dilute hydrofluoric acid at 20 V for 20 min to possess nanotubes, while titanium was anodized at 10 V for 20 min to possess nanoparticles. Most importantly, results showed that calcium deposition significantly increased on anodized titanium with nanotube‐like structures compared with unanodized titanium and anodized titanium with nanoparticulate structures after 21 days of osteoblast culture. In this manner, the results of the present in vitro study indicated that anodization might be a promising quick and inexpensive method to modify the surface of titanium‐based implants to induce better bone cell functions important for orthopedic applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008