bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel star PEG–derived surface coating for specific cell adhesion
Authors: Groll Juergen , Fiedler Joerg , Engelhard Erika , Ameringer Thomas , Tugulu Stefano , Klok Harm‐Anton , Brenner Rolf E. , Moeller Martin 
Published: July 2005

AbstractIn this study a novel approach for the coating and functionalization of substrates for cell culture and tissue engineering is presented. Glass, silicon, and titanium panes were coated with an ultrathin film (30 ± 5 nm) of reactive star‐shaped poly(ethylene glycol) prepolymers (Star PEG). Homogeneity of the films was checked by optical microscopy and scanning force microscopy. These coatings prevent unspecific protein adsorption as monitored by fluorescence microscopy and ellipsometry. In order to allow specific cell adhesion the films were modified with linear RGD peptides (gRGDsc) in different concentrations. After sterilization, fibroblast, SaOS, and human mesenchymal stem cells (hMSC) were seeded on these substrates. Cell adhesion, spreading, and survival was observed for up to 30 days on linear RGD peptide (gRGDsc)‐modified coatings, whereas no cell adhesion could be detected on unmodified Star PEG layers. By variation of the RGD concentration within the film the amount of cells that became adhesive could be controlled. When differentiation conditions are used for cultivation of hMSCs the cells show the expression of osteogenic marker genes after 14 days which is comparable to cultivation on cell culture plastic. Thus, the Star PEG/RGD film did not negatively influence the differentiation process. The high flexibility of the system considering the incorporation of biologically active compounds opens a broad field of future experiments. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Complement inhibition reduces material‐induced leukocyte activation with PEG modified polystyrene beads (Tentagel™) but not polystyrene beads
Authors: Gorbet M. B. , Sefton M. V. 
Published: July 2005

AbstractWith isolated leukocytes, inhibiting complement reduced material‐induced leukocyte activation (CD11b) with polyethylene glycol modified polystyrene beads (PS‐PEG), but not with polystyrene beads (PS). The PS‐PEG beads (TentaGel™) were complement activating as measured by SC5b‐9 levels consistent with the sensitivity of these beads to leukocyte inhibition with complement inhibitors. Following contact with PS and PS‐PEG beads, isolated leukocytes in plasma and in the absence in platelets were found to significantly upregulate CD11b, while TF expression and exposure of phosphatidylserine remained at background levels. Complement inhibition by means of sCR1 partially reduced CD11b upregulation on PS‐PEG beads, but had no effect with PS beads. Pyridoxal‐5‐phosphate (P5P) was able to significantly reduce both CD11b upregulation and exposure of phosphatidylserine with PS‐PEG beads, although it did not appear to inhibit SC5b‐9 production. Pentamidine and NAAGA inhibited complement and were effective in reducing CD11b upregulation with both PS and PS‐PEG. However, they also had an inhibitory effect on leukocyte signaling mechanisms, precluding their utility for further study in this context. Leukocyte adhesion occurred to similar extents on both PS and PS‐PEG beads. While sCR1 and P5P blocked adhesion and activation (for adherent leukocytes) on PS‐PEG beads, they had no effect on leukocytes adherent to PS beads. The role of complement in leukocyte activation and adhesion was found to be material‐dependent. Thus, leukocyte‐material compatibility may be resolved by complement inhibition in some but not all cases. For these other materials (example here was PS), other mechanisms, such as fibrinogen adsorption and direct leukocyte release, may need exploitation to minimize leukocyte activation and adhesion. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Increased osteoblast function on PLGA composites containing nanophase titania
Authors: Webster Thomas J. , Smith Tyler A. 
Published: July 2005

AbstractNanotechnology creates materials that potentially outperform, at several boundaries, existing materials in terms of mechanical, electrical, catalytic, and optical properties. However, despite their promise to mimic the surface roughness cells experience in vivo, the use of nanophase materials in biological applications remains to date largely unexplored. The objective of the present in vitro study was, therefore, to determine whether when added to a polymer scaffold, nanophase compared to conventional ceramics enhance functions of osteoblasts (or bone‐forming cells). Results from this study provided the first evidence that functions (specifically, adhesion, synthesis of alkaline phosphatase, and deposition of calcium‐containing mineral) of osteoblasts increased on poly‐lactic‐co‐glycolic acid (PLGA) scaffolds containing nanophase compared to conventional grain size titania with greater weight percentage (from 10–30 wt %). Because the chemistry, material phase, porosity (%), and pore size of the composites were similar, this study implies that the surface features created by adding nanophase compared to conventional titania was a key parameter that enhanced functions of osteoblasts. In this manner, the study adds another novel property of nanophase ceramics: their ability to promote osteoblast functions in vitro when added to a polymer scaffold. For this reason, nanophase ceramics (and nanomaterials in general) deserve further attention as orthopedic tissue engineering materials. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Mineralization of SaOS‐2 cells on enzymatically (silicatein) modified bioactive osteoblast‐stimulating surfaces
Authors: Schröder Heinz C. , Boreiko Oleksandra , Krasko Anatoli , Reiber Andreas , Schwertner Heiko , Müller Werner E. G. 
Published: July 2005

AbstractThere is a demand for novel bioactive supports in surgery, orthopedics, and tissue engineering. The availability of recombinant silica‐synthesizing enzyme (silicatein) opens new possibilities for the synthesis of silica‐containing bioactive surfaces under ambient conditions that do not damage biomolecules like proteins. Here it is shown that growth of human osteosarcoma SaOS‐2 cells on cluster plates precoated with Type 1 collagen is not affected by additional coating of the plates with the recombinant silicatein and incubation with its enzymatic substrate, tetraethoxysilane (TEOS). However, the enzymatic modification of the plates by biosilica deposition on the protein‐coated surface caused a marked increase in calcium phosphate formation of SaOS‐2 cells as revealed by alizarin red‐S staining to quantify calcium mineral content. The increased occurrence of calcium‐phosphate nodules on the modified surface was also observed by scanning electron microscopy. These results suggest that by supporting calcium‐phosphate deposition in vitro, biosilica (silicatein)‐modified surfaces are potentially bioactive in vivo, by stimulating osteoblast mineralization function. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Biological properties of photocrosslinked alginate microcapsules
Authors: Shen Feng , Li Anna Aihua , Cornelius Rena M. , Cirone Pasquale , Childs Ronald F , Brash John L. , Chang Patricia L. 
Published: July 2005

AbstractAn alternative form of gene therapy using recombinant cell lines delivering therapeutic products encapsulated in alginate hydrogel has proven effective in treating many murine models. The lack of long‐term capsule stability has led to a new strategy to reinforce the microcapsules with a photopolymerized interpenetrating covalent network of N‐vinylpyrrolidone (NVP) and sodium acrylate. Here the properties for potential application in gene therapy are reported. In assessing potential toxicity of the unpolymerized residues, HPLC showed that even after 1 week of washing, no toxic monomers could be detected. Their ability to sustain cell growth was monitored with growth of the encapsulated cells in vitro and in vivo. Although the initial photopolymerization caused significant cell damage, the cells were able to recover normal growth rates thereafter. After implanting into mice, the NVP‐modified capsules showed a high level of biocompatibility as measured by hematological and biochemical functional tests. There was also no difference in the amount and type of plasma proteins adsorbing to the NVP‐modified and the classical alginate capsules, thus indicating their similar biological compatibility. Both in vitro and in vivo tests confirmed that the NVP‐modified capsules were more resistant to osmotic stress than the alginate microcapsules. Furthermore, when applied to the treatment of a murine model of human cancer by delivering encapsulated cells secreting angiostatin, the NVP‐modified microcapsules suppressed tumor growth as successfully as the regular alginate microcapsules. In conclusion, the covalently modified microcapsules have shown a high level of biocompatibility, safety, increase in stability, and clinical efficacy for use as immunoisolation devices in gene therapy. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Matrix physicochemical properties affect activity of entrapped chlorophyllase
Authors: Yi Yunyu , Kermasha Selim , Neufeld Ronald 
Published: July 2005

AbstractChlorophyllase, a membrane glycoprotein, was entrapped in various matrices, including alginate, alginate–silicate mixed gel, TMOS‐based sol–gel, and their hydrophobically‐modified counterparts. Chlorophyllase activity was affected by the physicochemical properties of the matrix, demonstrating lower activity in organically‐modified matrices compared with the corresponding hydrophilic matrices. The advantage of adopting organically‐modified matrices to facilitate the transfer of hydrophobic substrate is likely compromised by detrimental interaction between chlorophyllase and the hydrophobic components. This hypothesis is at least partly substantiated by the negligible activity demonstrated by free chlorophyllase in hydrophobic micellar media. Even though activity yields exceeded 50% in alginate beads, the release profile reveals that alginate matrix is too porous to retain chlorophyllase. Although alginate–silicate mixed gel more effectively confined chlorophyllase in the matrix, only 16% of the activity was recovered. In contrast, inorganic sol–gel yielded a chlorophyllase preparation with mass yield above 90%, and activity yield above 50%. Doping additives did not improve activity yield, which could be explained by the lower specific surface area and pore volume, and hence possible restricted accessibility of chlorophyllase by its substrate. Water/silane ratio was found to affect the sol–gel‐entrapped chlorophyllase activity by influencing the gelation time and physical properties of the gel. Copyright © 2005 Society of Chemical Industry
Electrochemical removal of ammonia, chemical oxygen demand and energy consumption from aquaculture waters containing different marine algal species
Authors: Wijesekara RG Saman , Nomura Nakao , Matsumura Masatoshi 
Published: July 2005

AbstractPhytoplankton over‐blooming and consequent die‐off is one of the major contributory factors for ammonia and chemical oxygen demand (COD) loadings. In this work, electrolysis technology was applied to determine its ability to remove ammonia and total chemical oxygen demand (TCOD) in both laboratory‐scale batch and continuous systems. Under an initially set voltage of 5 V, a constant current of 0.1 A was applied and different retention times were used for ammonia‐removal experiments. Results showed that these conditions are not satisfactory in removing TCOD loadings contributed by algal cells. However, a retention time of 35.7 min was sufficient to remove 100% ammonia from algal‐uncontaminated waters. Ammonia removals in waters containing Chlorella spp and Isochrysis spp were 87 and 68%, respectively, after 140 min of electrolysis. Energy consumption for ammonia removal in algal‐free water was 50 W mg−1 of ammonia. For waters containing Chlorella spp and Isochrysis spp energy consumptions were 67 and 85 W mg−1 of ammonia, respectively. Interestingly, the applied mild electrolysis condition was just sufficient to control excess algal blooming and ammonia without increasing the dissolved COD and chlorine in shrimp grow‐out ponds. This minimizes operating costs due the process requiring less energy. Furthermore, it was also found that electrolysis does not lower alkalinity. Copyright © 2005 Society of Chemical Industry
Developmental neurotoxicology
Authors: Bondy Stephen C. , Campbell Arezoo 
Published: July 2005

AbstractThe developing brain has a distinctive set of characteristics that make it unusually sensitive to damage by toxic agents. Mechanistic understanding of the vulnerability of the immature nervous system to various chemicals is important from a preventive perspective but has also frequently given us new insights into maturation of neural circuitry. This review examines some of the developmental consequences of contact with various exogenous agents, including metals, solvents, pharmaceuticals, and natural products. This review emphasizes how subtle suboptimal brain function rather than acute toxicity can be a consequence of chemical exposures occurring during ontogenesis. The rate of brain aging may be influenced by events taking place in embryogenesis, following a prolonged asymptomatic period. The potential for appearance of adverse effects after prolonged latent periods is underscored. © 2005 Wiley‐Liss, Inc.
Direct profiling of the cerebellum by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry: A methodological study in postnatal and adult mouse
Authors: Laurent Claudine , Levinson Douglas F. , Schwartz Sarah A. , Harrington Peter B. , Markey Sanford P. , Caprioli Richard M. , Levitt Pat 
Published: July 2005

AbstractMatrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI MS) can detect substantial changes in expression of proteins in tissues, such as cancer cells. A more challenging problem is detecting the smaller changes expected in normal development or complex diseases. Here we address methodological issues regarding the acquisition and analysis of MALDI MS data from tissue sections, in a study of mouse cerebellum at different stages of development. Sections of the cerebellar cortex were analyzed at the peak of granule neuron production [postnatal day (P) 7], during synapse formation (P14), and in adults. Data were acquired (Voyager‐DE™ STR Biospectrometry Workstation; seven acquisitions of 50 shots per section, 3.5–50 kDa), preprocessed (Data Explorer 4.3), and averaged. Among 846 peaks detected, in at least 50% of at least one group, 122 showed significant group differences (Kruskal‐Wallis ANOVA) after Bonferroni correction. Factor analyses revealed two age‐related factors, possibly reflecting gradients of expression during development. Predictive analysis of microarrays generated a model from half of the sample that correctly predicted developmental groups for the second half. Intraclass correlation coefficients, measuring within‐mouse consistency of peak heights from three tissue sections, were acceptable at lower m/z and for larger peaks at higher m/z. Low mass was the best predictor of significant group differences. The analysis demonstrates that MALDI MS of normal tissue sections at different ages can detect consistent, significant group differences. Further work is needed to increase the sensitivity of the methods and to apply them reliably to brain regions and to subproteomes with relevance to diverse brain functions and diseases. © 2005 Wiley‐Liss, Inc.
Expression of N19S‐SOD1, an SOD1 mutant found in sporadic amyotrophic lateral sclerosis patients, induceslow‐grade motoneuronal toxicity
Authors: Obata Yuji , Niikura Takako , Kanekura Kohsuke , Hashimoto Yuichi , Kawasumi Masaoki , Kita Yoshiko , Aiso Sadakazu , Matsuoka Masaaki , Nishimoto Ikuo 
Published: July 2005

AbstractAmyotrophic lateral sclerosis (ALS) is the most common fatal motor neuron disease. It has been generally accepted that the proapoptotic property of the familial ALS (FALS)‐linked mutant SOD1 genes plays an important role in the pathogenesis of some FALS cases. We found here that expression of N19S‐SOD1, a novel SOD1 mutant originally found in a sporadic ALS patient, induces lower grade death in NSC34 cells than FALS‐linked mutant SOD1. In agreement, intracytoplasmic aggregate formation and SOD1 polymerization are less prominently induced by ectopic expression of N19S‐SOD1 than FALS‐linked mutant SOD1. We further found that additional cell stresses, such as inhibition of proteasomal activity or up‐regulation of intracellular oxidative stress, enhance N19S‐SOD1‐induced aggregate formation and polymerization of N19S‐SOD1. Such analysis of the intracellular polymerization and the ubiquitination of N19S‐SOD1 have further suggested that it is recognized as a misfolded protein, like FALS‐linked mutant SOD1, whereas wild‐type SOD1 is not. Altogether, it is speculated that the N19S mutation of SOD1 in cooperation with associated cell stresses contributes to the onset of ALS as a risk factor. © 2005 Wiley‐Liss, Inc.
Expression of the transcription factor Pax6 in the adult rat dentate gyrus
Authors: Nacher Juan , Varea Emilio , Blasco‐Ibañez Jose M. , Castillo‐Gomez Esther , Crespo Carlos , Martinez‐Guijarro Francisco J. , McEwen Bruce S. 
Published: July 2005

AbstractThe transcription factor Pax6 is expressed in precursor cells during embryonic CNS development, and it plays an important role in the regulation of cell proliferation and neuronal fate determination. Pax6‐expressing cells are also present in the adult hippocampal dentate gyrus and subventricular zone/rostral migratory stream, regions in which neuronal precursors exist during adult life. In the adult dentate gyrus, precursor cells are located in the innermost portion of the granule cell layer, and Pax6‐expressing nuclei are most abundant in this region. To examine the putative role of Pax6 in adult hippocampal neurogenesis, we have studied the proliferative activity, distribution, and phenotype of Pax6‐expressing cells by using immunohistochemistry. Our results indicate that Pax6 is intensely expressed in proliferating precursors of the adult dentate gyrus. Pax6 is also expressed in nonproliferating cells, which may correspond to resting progenitor cells and to granule neurons in their very early developmental stages, because this transcription factor is strongly down‐regulated during granule neuron differentiation. However, a small subpopulation of hilar mature neurons and certain astrocytes of the adult hippocampus also express Pax6. Although the precise roles of this transcription factor in the adult brain remain to be determined, our findings support the idea that its function in the control of cell proliferation and neuronal fate determination during embryogenesis is also operative in the adult hippocampus. However, the expression of Pax6 in astrocytes and certain mature neurons may indicate the existence of other roles for this transcription factor in this telencephalic region. © 2005 Wiley‐Liss, Inc.
Crack Toughness Behaviour of Multiwalled Carbon Nanotube (MWNT)/Polycarbonate Nanocomposites
Authors: Satapathy Bhabani K. , Weidisch Roland , Pötschke Petra , Janke Andreas 
Published: July 2005

AbstractSummary: The morphology and fracture behaviour of polycarbonate (PC)/multiwalled carbon nanotube (MWNT) composites have been studied by AFM and post‐yield fracture mechanics. The essential work of fracture (EWF) method has been used to distinguish between two terms representing the resistance to crack initiation and crack propagation. A maximum in the non‐essential work of fracture was observed at 2 wt.‐% MWNT, demonstrating enhanced resistance to crack propagation compared to pure PC. At 4 wt.‐% MWNT, a tough‐to‐brittle transition has been observed. The time‐resolved in‐situ strain field analysis revealed that the onset of crack initiation was shifted to a shorter time for nanocomposites with 4 wt.‐% MWNT compared to that with 2 wt.‐%, and thus explained the existence of a tough‐to‐brittle transition in these nanocomposites.
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Synthesis of Polyaniline‐Vanadium Oxide Nanocomposite Nanosheets
Authors: Pang Shuping , Li Guicun , Zhang Zhikun 
Published: July 2005

AbstractSummary: Polyaniline‐vanadium oxide nanocomposite nanosheets with thickness between 10 and 20 nm, and lateral dimensions in the range of hundreds of nanometers to several microns have been synthesized by in situ intercalation polymerization of aniline with layered V2O5 under hydrothermal conditions. The product was characterized by field‐emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT‐IR) spectroscopy, and X‐ray diffractometer (XRD). The effects of the concentration of aniline and reaction temperature on the morphologies of polyaniline‐vanadium oxide nanocomposites have also been investigated.SEM image of tremella‐like polyaniline‐vanadium oxide nanocomposite nanosheets.magnified imageSEM image of tremella‐like polyaniline‐vanadium oxide nanocomposite nanosheets.
Ambipolar Field‐Effect Transistor (FET) and Redox Characteristics of a π‐Conjugated Thiophene/1,3,4‐Thiadiazole CT‐Type Copolymer
Authors: Yamamoto Takakazu , Yasuda Takuma , Sakai Yoshimasa , Aramaki Shinji 
Published: July 2005

AbstractSummary: A π‐conjugated charge transfer‐type copolymer consisting of an electron‐donating thiophene and an electron‐accepting 1,3,4‐thiadiazole, P(ThdzTh), underwent facile electrochemical p‐ and n‐doping, as revealed by cyclic voltammetry. The copolymer gave a new ambipolar field‐effect transistor (FET), which showed typical IDS (source–drain current)–VDS (source–drain voltage) curves in both a p‐type working mode and an n‐type working mode. In the n‐type working mode, the polymer showed a carrier mobility of about 5 × 10−3 cm2 · V−1 · s−1 and an on/off ratio of about 3 × 104.n‐Channel field‐effect transistor characteristics of P(ThdzTh).magnified imagen‐Channel field‐effect transistor characteristics of P(ThdzTh).
Intra‐abdominal desmoid tumor after successful treatment for Hodgkin disease
Authors: Rosoff Philip M. , Larrier Nicole , Rice Henry E. 
Published: July 2005

AbstractThe risk of second malignancies after successful treatment for Hodgkin disease can be considerable. The most common malignancies are solid tumors arising in irradiated sites, such as the breast and thyroid gland after mantle field radiation. Sarcomas and other musculoskeletal tumors are also seen. We describe a young woman who developed an intra‐abdominal desmoid tumor more than 4 years after completing therapy for Stage IIB Hodgkin disease, treated with combination chemotherapy (ABVD) and mantle irradiation. The tumor did not occur at either a surgical site or within a radiation field. She did not carry a mutation for familial adenomatosis polypoli. © 2005 Wiley‐Liss, Inc.