bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anisotropic scaffolds facilitate enhanced neurite extension in vitro
Authors: Dodla Mahesh Chandra , Bellamkonda Ravi V. 
Published: May 2006

AbstractTissue engineering (TE) techniques to enhance nerve regeneration following nerve damage have had limited success in matching the performance of autografts across short nerve gaps (< 10 mm). For regeneration over longer nerve gaps, TE techniques have been less successful than autografts. Most engineered scaffolds do not present directional cues to the regenerating nerves. In our efforts to design a TE scaffold to replace the autograft, we hypothesize that anisotropic hydrogel scaffolds with gradients of a growth‐promoting glycoprotein, laminin‐1 (LN‐1), may promote directional neurite extension and enhance regeneration. In this study we report the engineering of three‐dimensional (3D) agarose scaffolds with photoimmobilized gradients of LN‐1 of differing slopes. Dorsal root ganglia (DRG) from chicken embryos were cultured in the agarose scaffolds and their neurite extension rate was determined. DRG neurite extension rates were significantly higher in the anisotropic scaffolds, with a maximal growth rate in an anisotropic scaffold twice that of the maximal growth rate in isotropic scaffolds of LN‐1. We suggest that these anisotropic scaffolds, presenting an optimal gradient of LN‐1, may significantly impact nerve regeneration. Such anisotropic scaffolds may represent a new generation of tissue engineered materials with built‐in directional cues for guided tissue or nerve regeneration. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Collagen I‐coated titanium surfaces: Mesenchymal cell adhesion and in vivo evaluation in trabecular bone implants
Authors: Morra M. , Cassinelli C. , Cascardo G. , Mazzucco L. , Borzini P. , Fini M. , Giavaresi G. , Giardino R. 
Published: May 2006

AbstractThe goal of the study was the evaluation of the effect of modification of titanium implants by acrylic acid surface grafting‐collagen I coupling. Tests were performed on titanium samples treated by galvanostatic anodization to create a porous surface topography. Surface characterization by X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) confirms the biochemical modification of the surface and shows a surface topography characterized by pores mostly below 1 μm diameter. In vitro evaluation involving human mesenchymal cells shows enhanced cell growth on collagen coated surfaces as compared to titanium ones. Four weeks in vivo evaluation of implants in rabbit femur trabecular bone shows improvements of bone‐to‐implant contact, while improvement of bone ingrowth is slightly not significant (p = 0.056), when compared to the control. Overall, these data indicate that integration in trabecular, or cancellous, bone can be enhanced by the surface collagen layer, confirming previous findings obtained by modification of machined surfaces by the same approach in cortical bone implants. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Isolation and characterization of UHMWPE wear particles down to ten nanometers in size from in vitro hip and knee joint simulators
Authors: Tipper J.L. , Galvin A.L. , Williams S. , McEwen H.M.J. , Stone M.H. , Ingham E. , Fisher J. 
Published: May 2006

AbstractThere is currently considerable interest in the wear debris and osteolytic potential of different types of bearings used in total joint replacements. The biological activity of the wear debris is dependent on the size and volume of the particles produced. Wear volume also plays an important role in the functional biological activity of a joint replacement. In vitro studies have shown that crosslinking of ultra high molecular weight polyethylene (UHMWPE) acetabular cups and tibial trays produces a reduction in wear volume, and crosslinking has now been introduced clinically for both types of prostheses. Previous studies have identified both micron and submicron‐sized polyethylene wear particles. The aim of this study was to characterize the wear and wear particles generated from moderately crosslinked GUR 1020 GVF UHMWPE acetabular cups and tibial trays in hip and knee joint wear simulators down to 10 nanometers in size. The wear rates of the two prosthesis types were very similar at 25.6 ± 5.3 mm3 per million cycles for the hip prostheses and 22.75 ± 5.95 mm3 per million cycles for the knee prostheses. Nanometer‐sized wear particles were isolated and characterized from both hip and knee simulator lubricants for the first time. Significantly higher numbers (p < 0.05) of particles in the nanometer (<0.1 μm) size range were produced by the hip prostheses compared to the knee prostheses. The knee prostheses produced larger particles, with the mode of particle size in the 0.1–1.0 μm size range, compared to <0.1 μm size range for the hip prostheses. In addition, the knee prostheses produced a greater volumetric concentration of wear particles in the 1.0–10 μm size range, and consequently lower specific biological activity and functional biological activity indices. These results indicated that the knee prostheses had a lower osteolytic potential compared to the hip prostheses. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Molecular vibrational analysis and MAS‐NMR spectroscopy study of epilepsy drugs encapsulated in TiO2‐sol–gel reservoirs
Authors: Lopez T. , Navarrete J. , Conde R. , Ascencio J.A. , Manjarrez J. , Gonzalez R.D. 
Published: May 2006

AbstractA nanostructured matrix, consisting of titania, was designed in such a way that an antiepileptic drug could be encapsulated and released according to a well‐defined time release schedule. The titania was synthesized by a sol–gel method in which titanium n‐butoxide was used as the precursor for the formation of the sol. The synthesis was optimized to yield a homogeneous particle size with a high porosity and an anatase crystal structure. The antiepilectic drugs, phenytoine or valproic acid, were added during the gelation stage in order to obtain a homogeneous gel phase. The resulting nanostructured matrix including the drug showed only weak attractive forces, such as London forces, dipole–dipole coupling, and in some cases hydrogen bonds. The resulting assembly, referred to as a reservoir, was characterized using conventional FTIR and NMR spectroscopic techniques. Theoretical simulation studies were performed so as to obtain an understanding of the equilibrium electrostatic potential distribution and the relative charges on the titania and the anticonvulsants. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
In vitro testing of calcium phosphate (HA, TCP, and biphasic HA‐TCP) whiskers
Authors: Jalota Sahil , Bhaduri Sarit B. , Tas A. Cuneyt 
Published: May 2006

AbstractCalcium phosphate [single‐phase hydroxyapatite (HA, Ca10(PO4)6(OH)2), single‐phase tricalcium phosphate (β‐TCP, Ca3(PO4)2), and biphasic HA‐TCP] whiskers were formed by using a novel microwave‐assisted molten salt mediated process. Aqueous solutions containing NaNO3, HNO3, Ca(NO3)2·4H2O, and KH2PO4 (with or without urea) were used as starting reagents. These solutions were irradiated in a household microwave oven for 5 min. As‐recovered precursors were then simply stirred in water at room temperature for 1 h to obtain the whiskers of the desired calcium phosphate (CaP) bioceramics. These whiskers were evaluated, respectively, in vitro by (1) soaking those in synthetic body fluid (SBF) solutions at 37°C for one week, and (2) performing cell attachment and total protein assay tests on the neat whiskers by using a mouse osteoblast cell line (7F2). β‐TCP, HA, and HA‐TCP biphasic whiskers were all found to possess apatite‐inducing ability when soaked in SBF. SBF‐soaked whiskers were found to have BET surface areas ranging from 45 to 112 m2/g. Although the osteoblast viability and protein concentrations were found to be the highest on the neat HA whiskers, cells were attached and proliferated on all the whiskers. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Expression of genes regulating Malonyl‐CoA in human skeletal muscle
Authors: Pender Celia , Trentadue Anna R. , Pories Walter J. , Dohm G. Lynis , Houmard Joseph A. , Youngren Jack F. 
Published: May 2006

AbstractIn humans and animal models, increased intramuscular lipid (IML) stores have been implicated in insulin resistance. Malonyl‐CoA plays a critical role in cellular lipid metabolism both by serving as a precursor in the synthesis of lipids and by inhibiting lipid oxidation. In muscle, Malonyl‐CoA acts primarily as a negative allosteric regulator of carnitine palmitoyl transferase‐1 (CPT1) activity, thereby blocking the transport of long chain fatty acyl CoAs into the mitochondria for oxidation. In muscle, increased malonyl‐CoA, decreased muscle CPT1 activity, and increased IML have all been reported in obesity. In order to determine whether malonyl‐CoA synthesis might be under transcriptional as well as biochemical regulation, we measured mRNA content of several key genes that contribute to the cellular metabolism of malonyl‐CoA in muscle biopsies from lean to morbidly obese subjects. Employing quantitative real‐time PCR, we determined that expression of mitochondrial acetyl‐CoA carboxylase 2 (ACC2) was increased by 50% with obesity (P < 0.05). In both lean and obese subjects, expression of mitochondrial ACC2 was 20‐fold greater than that of cytoplasmic ACC1, consistent with their hypothesized roles in synthesizing malonyl‐CoA from acetyl‐CoA for CPT1 regulation and lipogenesis, respectively. In addition, in both lean and obese subjects, expression of malonyl‐CoA decarboxylase was approximately 40‐fold greater than fatty acid synthase, consistent with degradation, rather than lipogenesis, being the primary fate of malonyl‐CoA in human muscle. No other genes showed signs of increased mRNA content with obesity, suggesting that there may be selective transcriptional regulation of malonyl‐CoA metabolism in human obesity. J. Cell. Biochem. 99: 860–867, 2006. © 2006 Wiley‐Liss, Inc.
Identification of mannose moieties in N‐ and O‐linked oligosaccharides of the primordial germ cells of Xenopus embryos
Authors: Alonso Edurne , Gómez Laura , Madrid Juan Francisco , Sáez Francisco José 
Published: May 2006

AbstractThe presence of mannose (Man) in the glycoconjugates of primordial germ cells (PGCs) of Xenopus embryos was elucidated by lectin histochemistry with Concanavalin A (Con A) and snowdrop (Galanthus nivalis) bulb lectin (GNA), in combination with deglycosylative pretreatments: β‐elimination, which removes O‐linked oligosaccharides, and incubation with Peptide N glycosidase F (PNGase F), which removes N‐linked glycan chains. In addition, histochemistry with Con A, which binds to Man and glucose (Glc), was also performed after glucose‐oxidase incubation, which converts Glc into gluconic acid, and GNA was carried out after acid hydrolysis, which removes terminal sialic acid (NeuAc) moieties. PGCs were analyzed during their migration over the mesentery until the genital ridge, and after colonization of this gonad anlage. The results showed that for both lectins: (1) the PGCs and other surrounding tissue showed a similar binding pattern, and (2) the staining in the PGCs was similar in the developmental stages studied. Labeling with Con A was due to Man, and not to Glc, as shown after incubation with glucose‐oxidase, and it was assumed that Man was in N‐linked oligosaccharides. However, GNA labeling was mainly due to O‐linked oligosaccharides, because the pretreatment of β‐elimination turned cells negative. Moreover, acid hydrolysis pretreatment gave rise to a stronger GNA‐staining, suggesting that either Man was also in subterminal position to NeuAc or some Man‐containing glycans were unmasked after removal of NeuAc from other oligosaccharide chains. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.
Mechanism of plasmid delivery by hydrodynamic tail vein injection. II. Morphological studies
Authors: Budker Vladimir G. , Subbotin Vladimir M. , Budker Tatiana , Sebestyén Magdolna G. , Zhang Guofeng , Wolff Jon A. 
Published: May 2006

AbstractBackgroundThe efficient delivery of plasmid DNA (pDNA) to hepatocytes by a hydrodynamic tail vein (HTV) procedure has greatly popularized the use of naked nucleic acids. The hydrodynamic process renders onto the tissue increased physical forces in terms of increased pressures and shear forces that could lead to transient or permanent membrane damage. It can also trigger a series of cellular events to seal or reorganize the stretched membrane. Our goal was to study the uptake mechanism by following the morphological changes in the liver and correlate these with the fate of the injected plasmid DNA.MethodsWe utilized both light microscopic (LM) and electron microscopic (EM) techniques to determine the effect of the HTV procedure on hepatocytes and non‐parenchymal cells at various times after injection. The LM studies used paraffin‐embedded livers with hematoxylin and eosin (H&E) staining. The immune‐EM studies used antibodies labeled with sub‐nanometer gold particles followed by silver enhancement to identify the location of injected pDNA at the subcellular level. The level of overall damage to liver cells was estimated based on alanine aminotransferase (ALT) release and clearance.ResultsBoth the LM and EM results showed the appearance of large vesicles in hepatocytes as early as 5 min post‐injection. The number of vesicles decreased by 20–60 min. Plasmid DNA molecules often appeared to be associated with or inside such vesicles. DNA could also be detected in the space of Disse, in the cytoplasm and in nuclei. Non‐parenchymal cells also contained DNA, but HTV‐induced vesicles could not be observed in them.ConclusionsOur studies suggest an alternative or additional pathway for naked DNA into hepatocytes besides direct entry via membrane pores. It may be difficult to prove which of these pathways lead to gene expression, but the membrane pore hypothesis alone appears insufficient to explain why expression happens preferentially in hepatocytes. Further study is needed to delineate the importance of each of these putative pathways and their interrelationship in enabling oligonucleotide (siRNA) activity and pDNA expression. Copyright © 2006 John Wiley & Sons, Ltd.
Reform complementarities and economic growth in the Middle East and North Africa
Authors: Nabli Mustapha Kamel , Véganzonès‐Varoudakis Marie‐Ange 
Published: May 2006

AbstractIn this paper we empirically analyse the linkages amongst economic reforms, human capital, physical infrastructure, and growth for a panel of 44 developing countries over 1970–1980 to 1999. For this purpose, we generate aggregated reform indicators using principal component analysis. We show that the growth performance of Middle East and North Africa (MENA) has been disappointing because these economies have lagged behind in terms of economic reforms. However, our analysis also reveals that the growth dividend of some reforms has been small. This is the case when structural reforms are implemented in an unstable macroeconomic environment (which corresponds to the situation of the MENA countries in the 1980s), and when macroeconomic reforms are accompanied by a low level of structural reforms (as observed during the 1990s). Our result illustrates the complementarities between reforms as modelled by Mussa (1987) and Williamson (1994). Actually, after human capital and physical infrastructure, our analysis finds that macroeconomic and external stability are key variables for the reform process and for the growth prospects of the developing world. Copyright © 2006 John Wiley & Sons, Ltd.
Interleukin‐1α stimulates non‐amyloidogenic pathway by α‐secretase (ADAM‐10 and ADAM‐17) cleavage of APP in human astrocytic cells involving p38 MAP kinase
Authors: Bandyopadhyay Sanghamitra , Hartley Dean M. , Cahill Catherine M. , Lahiri Debomay K. , Chattopadhyay Naibedya , Rogers Jack T. 
Published: May 2006

AbstractInterleukin‐1α (IL‐1α) stimulates a disintegrin and metalloproteinase, ADAM‐17 synthesis, consistent with activation of the soluble fragment of Amyloid Precursor Protein, APP, (sAPPα) in human primary astrocytes. To characterize the mechanism by which IL‐1α promotes the non‐amyloidogenic pathway of APP metabolism, we used U373 MG astrocytoma cells. IL‐1α significantly increased levels of ADAM‐10 and ADAM‐17 mRNA in 16 hr. Upregulation of ADAM‐17 mRNA by IL‐1α was more pronounced despite higher basal levels of ADAM‐10 mRNA. This pattern was also observed at the protein level with the upregulation of α‐secretase. RNA interference (RNAi) of ADAM‐10 and ADAM‐17 inhibited IL‐1α‐stimulated sAPPα release and the effect was more pronounced with ADAM‐17 RNAi. Concomitantly, the level of sAPPα was significantly increased by IL‐1α in 48 hr; however, IL‐1α stimulated cell‐associated APP levels maximally at 6 h but the induction declined at 48 hr. IL‐1α treatment of cells for 48 h reduced both intracellular and secreted levels of amyloid‐β, Aβ‐40, and Aβ‐42 peptides. Multiple MAP kinases (MAPK), including MEK/ERK, p38 kinase, PI3 kinase (PI3K) but not JNK were involved in the regulation of IL‐1α‐stimulated α‐secretase activity and sAPPα release. p38 MAPK seems to be the most proximal of these MAPKs, as it was the earliest to be activated by IL‐1α and blocking this pathway attenuated activation of IL‐1α‐induced MEK and PI3K pathways. Our data show a complex mechanism of sAPPα regulation by IL‐1α that involves ADAM‐10, ADAM‐17 and p38 MAPK upstream of MEK and PI3K. © 2006 Wiley‐Liss, Inc.
Evaluation of antibacterial activity of extracts of five species of wood‐colonizing fungi
Authors: Janeš Damjan , Umek Andrej , Kreft Samo 
Published: May 2006

AbstractScreening new organisms for antibacterial activity and searching for new antibacterial drugs is important due to the constant generation of new antibiotic‐resistant strains of pathogenic bacteria. An E. coli broth microdilution test was used to evaluate the results of the Vibrio fischeri bioluminescence test in five of the most antibacterially active species of wood‐colonizing fungi. Serpula lacrymans was found to be a potential source of thermostable antibiotic(s) and the Vibrio fischeri bioluminescence test was confirmed to be a useful method for screening for antibacterial activity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of bacteriocin HV219, produced by Lactococcus lactis subsp. lactis HV219 isolated from human vaginal secretions
Authors: Todorov Svetoslav D. , Danova Svetla T. , Van Reenen Carol A. , Meincken Martina , Dinkova Galina , Ivanova Iskra V. , Dicks Leon M. T. 
Published: May 2006

AbstractBacteriocin HV219, produced by Lactococcus lactis subsp. lactis HV219, is active against Gram‐positive and Gram‐negative bacteria. Activity was lost when treated with proteolytic enzymes, SDS, Triton X‐114 and Triton X‐100, but not at pH 2.0 to 10.0 or after 20 min at 121 °C. Growth in the presence of yeast extract as sole nitrogen source yielded 3200 AU/ml. No bacHV219 activity was recorded in MRS broth with maltose, mannose, lactose or sucrose as sole carbohydrate, but fructose yielded 1600 AU/ml. K2HPO4 at 10.0 g/l yielded 3200 AU/ml. Addition of 1.0 mg/l cyanocobalamin, l‐ascorbic acid and thiamine to MRS broth yielded 3200 AU/ml, 1600 AU/ml and 1600 AU/ml, respectively. The mode of activity is bacteriolytic, as confirmed by atomic force microscopy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Plant growth promotion and induction of resistance in Camellia sinensis by Bacillus megaterium
Authors: Chakraborty Usha , Chakraborty Bishwanath , Basnet Merab 
Published: May 2006

AbstractBacillus megaterium de Bary TRS‐4 was isolated from tea rhizosphere and tested for its ability to promote growth and cause disease reduction in tea plants. In vivo studies revealed the ability of this bacterium to promote growth of tea plants very significantly. Brown root rot disease, caused by Fomes lamaoensis was markedly reduced by application of the bacterium to the soil. Population of F. lamaoensis in soil before and after application of B. megaterium, as determined by ELISA and dot‐blot using PAb raised against the pathogen, was shown to be greatly reduced in presence of the bacterium. Biochemical changes induced in tea plants were also examined. Root colonization by B. megaterium and subsequent inoculation with F. lamaoensis also led to an increase in polyphenolics, as well as in defense related enzymes‐peroxidase, chitinase, β ‐1,3‐glucanase and phenyl alanine ammonia lyase. Determination of mechanism of action of this bacterium revealed it to be able to solubilize phosphate, produce IAA, siderophore and antifungal metabolite. The plant growth promotion and reduction of disease intensity have been shown to be due to a combination of several mechanisms. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A mathematical model of Saccharomyces cerevisiae growth in response to cadmium toxicity
Authors: Hietala Katie A. , Lynch Miranda L. , Allshouse John C. , Johns Craig J. , Roane Timberley M. 
Published: May 2006

AbstractMicrobial growth can be described using models derived by differential equations, but available mathematical models have yet to adequately describe lag phase related cell growth or cell mortality in response to chemical toxicity. Lag phase cell behavior, however, dictates the onset of exponential growth and the number of actively growing cells available to initiate exponential growth, important factors in the success of remediation efforts. In this study, a five‐parameter polynomial ratio (PR) model was used to characterize the growth, from lag through stationary phase, of the yeast Saccharomyces cerevisiae in response to cadmium toxicity. The PR model used in this study has the advantages over standard mathematical models in the ability to represent the initial cell mortality observed when S. cerevisiae is exposed to increasing cadmium levels, up to 12 mg/l Cd, as well as following cell recovery and growth to stationary levels. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Screening and selection of most potent diazotrophic cyanobacterial isolate exhibiting natural tolerance to rice field herbicides for exploitation as biofertilizer
Authors: Singh Surendra , Datta Pallavi 
Published: May 2006

AbstractPeriodic applications of heavy dosages of herbicides in modern rice‐agriculture are a necessary evil for obtaining high crop productivity. Such herbicides are not only detrimental to weeds but biofertilizer strains of diazotrophic cyanobacteria also. It is therefore, essential to screen and select such biofertilizer strains of diazotrophic cyanobacteria exhibiting natural tolerance to common rice‐field herbicides that can be further improved by mutational techniques to make biofertilizer technology a viable one. Therefore, efforts have been made to screen five dominant diazotrophic cyanobacterial forms e.g. filamentous heterocystous Nostoc punctiforme , Nostoc calcicola , Anabaena variabilis and unicellular Gloeocapsa sp. and Aphanocapsa sp. along with standard laboratory strain Nostoc muscorum ISU against increasing concentrations (0–100 mg l–1) of four commercial grade common rice‐field herbicides i.e. Arozin, Butachlor, Alachlor and 2,4‐D under diazotrophic growth conditions. The lethal and IGC50 concentrations for all four herbicides tested were found highest for A. variabilis as compared to other test cyanobacteria. The lowest reduction in chlorophyll a content, photosynthetic oxygen evolution, and N2‐fixation was found in A. variabilis as compared to other rice field isolates and standard laboratory strain N. muscorum ISU. On the basis of prolong survival potential and lowest reductions in vital metabolic activities tested at IGC50 concentration of four herbicides, it is concluded that A. variabilis is the most potent and promising cyanobacterial isolate as compared with other forms. This could be further improved by mutational techniques for exploitation as most potential and viable biofertilizer strain. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)