bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection and analysis of protein–protein interactions in organellar and prokaryotic proteomes by native gel electrophoresis: (Membrane) protein complexes and supercomplexes
Authors: Krause Frank 
Published: July 2006

AbstractIt is an essential and challenging task to unravel protein–protein interactions in their actual in vivo context. Native gel systems provide a separation platform allowing the analysis of protein complexes on a rather proteome‐wide scale in a single experiment. This review focus on blue‐native (BN)‐PAGE as the most versatile and successful gel‐based approach to separate soluble and membrane protein complexes of intricate protein mixtures derived from all biological sources. BN‐PAGE is a charge‐shift method with a running pH of 7.5 relying on the gentle binding of anionic CBB dye to all membrane and many soluble protein complexes, leading to separation of protein species essentially according to their size and superior resolution than other fractionation techniques can offer. The closely related colorless‐native (CN)‐PAGE, whose applicability is restricted to protein species with intrinsic negative net charge, proved to provide an especially mild separation capable of preserving weak protein–protein interactions better than BN‐PAGE. The essential conditions determining the success of detecting protein–protein interactions are the sample preparations, e.g. the efficiency/mildness of the detergent solubilization of membrane protein complexes. A broad overview about the achievements of BN‐ and CN‐PAGE studies to elucidate protein–protein interactions in organelles and prokaryotes is presented, e.g. the mitochondrial protein import machinery and oxidative phosphorylation supercomplexes. In many cases, solubilization with digitonin was demonstrated to facilitate an efficient and particularly gentle extraction of membrane protein complexes prone to dissociation by treatment with other detergents. In general, analyses of protein interactomes should be carried out by both BN‐ and CN‐PAGE.
Expression and function of calcium‐activated potassium channels in human glioma cells
Authors: Weaver Amy K. , Bomben Valerie C. , Sontheimer Harald 
Published: June 2006

AbstractCa2+‐activated K+ (KCa) channels are a unique family of ion channels because they are capable of directly communicating calcium signals to changes in cell membrane potential required for cellular processes including but not limited to cellular proliferation and migration. It is now possible to distinguish three families of KCa channels based on differences in their biophysical and pharmacological properties as well as genomic sequence. Using a combination of biochemical, molecular, and biophysical approaches, we show that human tumor cells of astrocytic origin, i.e. glioma cells, express transcripts for all three family members of KCa channels including BK, IK, and all three SK channel types (SK1, SK2, and SK3). The use of selective pharmacological inhibitors shows prominent expression of currents that are inhibited by the BK channel specific inhibitors iberiotoxin and paxilline. However, despite the presence of transcripts for IK and SK, neither clotrimazole, an inhibitor of IK channels, nor apamin, known to block most SK channels inhibited any current. The exclusive expression of functional BK channels was further substantiated by shRNA knockdown experiments, which selectively reduced iberiotoxin sensitive currents. Western blotting of patient biopsies with antibodies specific for all three KCa channel types further substantiated the exclusive expression of BK type KCa channels in vivo. This finding is in sharp contrast to other cancers that express primarily IK channels. © 2006 Wiley‐Liss, Inc.
Improving irrigated agriculture performance through an understanding of the water delivery process
Authors: Clemmens Albert J. 
Published: June 2006

AbstractThe performance of large‐scale irrigation projects worldwide has been disappointing to the international community. Continued poor performance could limit our ability to provide food and fibre for a growing, more affluent world population. Improvement in the productivity of large irrigation systems is a key component to assuring future adequate food and fibre supplies. This paper discusses the reasons for poor performance of these schemes and proposes a method to improve their performance. A main problem is that operation of these irrigation systems is not tied to productivity. As a result, the dispersive nature of these large open canal distribution systems causes extreme variability in water delivery service to users. The remedy is to break the system down at key intermediate locations within the network and to improve physical and administrative control at those locations. Published in 2006 by John Wiley & Sons, Ltd.
Impacts of drainage activities for clay soils on hydrology and solute loads to surface water
Authors: van den Eertwegh G. A. P. H. , Nieber J. L. , de Louw P. G. B. , van Hardeveld H. A. , Bakkum R. 
Published: July 2006

AbstractSeveral extended field‐monitoring programmes were set up in the Netherlands to study hydrological and surface water quality impacts of agricultural drainage activities for clay soils.At the field scale, agricultural land use data and hydrological measurements were combined with analysis of drainage water quality data, and related to the loading of the surface water system with salts and nutrients. Water, salt, and nutrient balances of the soil and/or surface water system were set up to analyse the hydrological behaviour of the systems studied and to quantify solute sources.Field observations were performed by field data analysis and numerical modelling, using the 1D F1W‐MultiSWAP code, a 2D dual‐porosity code, and the MODFLOW code. Drainage activities showed a significant impact on hydrology by influencing subsurface drainage water flow paths and regional‐scale groundwater seepage.Through solute balances it was shown that the salt and nutrient loading of the surface water were clearly affected by both agricultural and drainage activities. The conclusion was that the drainage activities and their surface water quality aspects need to be studied in an integrated way. Changes in subsurface drainage system redesign, surface water level management, and the field‐scale nutrient management need to be integrated. Copyright © 2006 John Wiley & Sons, Ltd.
Global gene expression analysis of the effects of vinblastine on endothelial cells, when eluted from a thermo‐responsive polymer
Authors: McLucas E. , Gallagher H. , Rochev Y. , Carroll W.M. , Gorelov A. , Smith T.J. 
Published: June 2006

AbstractIn‐stent restenosis remains a significant problem associated with bare metal stents. This drawback has prompted research into improving stent design and the development of novel coatings, including drug‐eluting stents. A number of drug‐eluting stents are currently on the market; however, the success rate of these stents in complex situations has been found to be quite low. Thus, there remains potential for the development of more suitable drug‐eluting stents. The aims of this study were to use a thermoresponsive polymer to develop a system to locally deliver vinblastine, an antimitotic agent currently used as an anticancer drug, and in addition, assess the effects of this drug at the gene expression level in vitro. An N‐isopropylacrylamide/N‐tert‐butylacrylamide (NiPAAm/NtBAAm) copolymer solution in the ratio 65:35 was prepared and appropriate volumes of vinblastine were added to generate two final drug concentrations of 22 nanomoles/film or 0.022 nanomoles/film. Stainless steel discs (316) were coated with the copolymer solution or this solution containing drug. Human endothelial cells were cultured on collagen type 1 gels and then incubated with the coated discs for 24 h. Gene expression studies using oligonucleotide microarray analysis and quantitative RT‐PCR were then performed. Microarray analysis revealed that vinblastine causes the differential expression of a range of genes involved in a variety of different functions, including cell cycle and apoptosis. The changes in expression of some of these genes culminate in cell cycle arrest and apoptotic pathways. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Biomineralization of polyanionic collagen–elastin matrices during cavarial bone repair
Authors: Rocha Lenaldo B. , Adam Randall L. , Leite Neucimar J. , Metze Konradin , Rossi Marcos A. 
Published: June 2006

AbstractThe polyanionic collagen–elastin matrices (PCEMs) are osteoconductive scaffolds that present high biocompatibility and efficacy in the regeneration of bone defects. In this study, the objective was to determine if these matrices are directly mineralized during the osteogenesis process and their influence in the organization of the new bone extracellular matrix. Samples of three PCEMs, differing in their charge density, were implanted into critical‐sized calvarial bone defects created in rats and evaluated from 3days up to 1 year after implantation. The implanted PCEMs were directly biomineralized by osteoblasts as shown by ultrastructural, histoenzymologic, and morphologic analysis. The removal of the implants occurred during the bone remodeling process. The organization of the new bone matrix was evaluated by image texture analysis determining the Shannon's entropy and the fractal dimension of digital images. The bone matrix complexity decreased as the osteogenesis progressed approaching the values obtained for the original bone structure. These results show that the PCEMs allow faster formation of new bone by direct biomineralization of its structure and skipping the biomaterial resorption phase. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Substrate mineralization stimulates focal adhesion contact redistribution and cell motility of bone marrow stromal cells
Authors: Leonova Elena V. , Pennington Keith E. , Krebsbach Paul H. , Kohn David H. 
Published: June 2006

AbstractUnderstanding the mechanisms of substrate based control of cell function is critical to the design of biomaterials. Cells interact with their extracellular matrix through cell adhesion contacts. We have previously described the self assembly of bone‐like mineral onto an organic template and have shown that these biomimetic surfaces lead to an increased volume fraction of bone regenerated in vivo. In the present study, we compared the distribution of cell adhesion contacts, cell spreading, and cell motility of murine bone marrow stromal cells (BMSC) on mineralized vs. nonmineralized substrates. We developed a new approach for quantification of cell‐material interactions and demonstrated that cell adhesion contacts on mineralized substrates were distributed throughout the cell surface contacting the substrate, whereas on nonmineralized substrates cell adhesion contacts were present near the cell periphery. We propose that mineralized substrates stimulate the predominant expression of fibrillar contacts, and nonmineralized substrates stimulate expression of focal adhesion contacts. Cell motility assays with colloidal gold demonstrated a statistically significant decrease in the average phagokinetic index of migrating cells on mineralized vs. nonmineralized substrates after 90 min of cell seeding. We propose that the physical–chemical properties of the substrate, altered by mineralization, cause expression of specific types of cell contacts and, as a result, modify molecular mechanisms responsible for cell spreading, motility, and possibly differentiation. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Adsorption of bisphosphonate onto hydroxyapatite using a novel co‐precipitation technique for bone growth enhancement
Authors: McLeod Kate , Anderson Gail I. , Dutta Naba K. , Smart Roger St.C. , Voelcker Nicolas H. , Sekel Ron , Kumar Sunil 
Published: June 2006

AbstractPremature bone resorption and remodeling by osteoclasts can limit the longevity of implant fixation and recovery time. Orally administered bisphosphonates (BPs) have been used to inhibit osteoclast action at the implant/bone interface. Ideally, these should be delivered at the interface with the osteoblast‐active hydroxyapatite (HA) for maximum effect. This investigation introduces a novel BP loading technique to achieve improved BP release from a simulated body fluid‐grown HA (SBF‐HA) with the aim of improving implant fixation. A solution co‐precipitation technique incorporates the BP (pamidronate) into a thin SBF‐HA coating. Surface analysis, using X‐ray photoelectron spectroscopy (XPS), of the resultant coating was employed to confirm the presence of the adsorbed BP on the surface of SBF‐HA. XPS analysis was also used to determine the optimal adsorption process. Osteoclast cell culture experiments confirmed the biological effectiveness of BP adsorption and proved that the pamidronate was biologically active, causing both decreased osteoclast numbers and decreased resorption. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Strain patterns during tensile, compressive, and shear fatigue of human cortical bone and implications for bone biomechanics
Authors: Winwood K. , Zioupos P. , Currey J.D. , Cotton J.R. , Taylor M. 
Published: June 2006

AbstractIt is a common theme in basic bone biomechanics and in biomechanical applications that much of the behavior can be determined and is dictated by the level of strain, whether this pertains to bone physiology, bone remodeling, osseoinduction, osseointegration, or the development of damage. The development of damage, demonstrated by stiffness loss measurements, has already been reported in detail in the literature. However, the systematic study of the development of “plastic” (residual) strains, which are associated with the inelastic mechanical behavior of bone tissue, has generally been overlooked. The present study compares the rates at which the elastic (ea) and plastic components (ep) of strain developed during tensile, compressive, and shear fatigue in human cortical bone of six individuals aged between 53 and 79 years. The overall hypothesis of this investigation is that there is a common underlying factor in the damage‐related behavior of bone, which may allow us to link together the various aspects of the damage related behavior of bone. The rate of development of plastic strain (Δep/ΔN) and the rate of growth in elastic strain amplitude (Δea/ΔN) are described as a function of the stress (σ), and/or stress normalized by the modulus of elasticity (σ/E). The implications of our findings are discussed with respect to simple models/mechanisms, which may underlie the observed behavior. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Effects of interconnecting porous structure of hydroxyapatite ceramics on interface between grafted tendon and ceramics
Authors: Omae Hiromichi , Mochizuki Yu , Yokoya Shin , Adachi Nobuo , Ochi Mitsuo 
Published: June 2006

AbstractThe purpose of this study was to evaluate histologically and biomechanically the interface between porous hydroxyapatite ceramics and a tendon grafted into ceramics, and to compare the interface in two ceramics with different porous structures: interconnected porous calcium hydroxyapatite ceramics (IP‐CHA) with an effective porosity index (interpore diameter > 20 μm) of 63.6%, and porous calcium hydroxyapatite ceramics with less interconnection (HA‐L) with an effective porosity index of 5.5%. The tendon‐IP‐CHA complex and the tendon‐HA‐L complex were implanted into the bone defects made in both knees of rabbits. With IP‐CHA, abundant fibrous tissue, including vessels and collagen fiber continuity, was observed inside interface‐region pores. The amount of osseous tissue in interface‐region pores increased over time, and at 24 weeks after operation, the tendon was in direct contact with the osseous tissue in IP‐CHA. With HA‐L, the amount of fibrous tissue in interface‐region pores was low and did not increase. The results of biomechanical analysis revealed that the maximum tendon pull‐out load from IP‐CHA was significantly higher than that from HA‐L. With the porous hydroxyapatite ceramics having highly interconnecting porous structure, a bioactive interface was achieved between ceramics and grafted tendon. On the basis of these results, we conclude that bone defects, including tendon insertion, can be reconstructed using IP‐CHA. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Mineralization of hydroxyapatite in electrospun nanofibrous poly(L‐lactic acid) scaffolds
Authors: Chen Jinglu , Chu Benjamin , Hsiao Benjamin S. 
Published: June 2006

AbstractA highly porous electrospun poly(L‐lactic acid) (PLLA) nanofibrous scaffold was used as a matrix for mineralization of hydroxyapatite. The mineralization process could be initiated by immersing the electrospun scaffold in the simulated body fluids (SBF) at 37°C for varying periods of time. Scanning electron microscopy (SEM), energy‐dispersive spectroscopy (EDS), wide‐angle X‐ray diffraction (WAXD), Fourier transform infrared (FTIR), and Raman spectroscopy were used to characterize the composition and the structure of the deposited mineral on the nanofiber surface. Results indicated that the mineral phase was a carbonated apatite with thin flake‐like nanostructures. The effects of functional groups on the scaffold surface and anionic additives in the incubation fluids on the nucleation and growth of the mineral were investigated. It was found that a minuscule amount of anionic additives (e.g., citric acid and poly‐L‐aspartic acid) in the SBF could effectively inhibit the mineral growth. Surface modification of the scaffold was carried out by hydrolysis of PLLA scaffold in NaOH aqueous solution, where carboxylic acid groups were produced without compromising the scaffold integrity. The mineralization process from modified PLLA electrospun scaffolds was significantly enhanced because the calcium ions can bind to the carboxylate groups on the fiber surface. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Effects of biomaterial surface chemistry on the adhesion and biofilm formation of Staphylococcus epidermidis in vitro
Authors: MacKintosh Erin E. , Patel Jasmine D. , Marchant Roger E. , Anderson James M. 
Published: June 2006

AbstractThe formation of biofilm, a structured community of bacteria enclosed in slime, is a significant virulence factor in medical‐device‐centered infection. The development of cardiovascular device infection can be separated into two phases: initial bacterial adhesion and aggregation, followed by proliferation and production of slime. It is possible to modulate the adhesion and biofilm formation of Staphylococcus epidermidis, a commensal skin bacterium commonly found on infected medical devices, through biomaterial surface chemistry. This study examines bacterial adhesion and biofilm formation on surface‐modified polyethylene terephthalate (PET), including surfaces with varying hydrophilic, hydrophobic, and ionic character. Bacterial adhesion and biofilm formation were observed over 48 hours in phosphate‐buffered saline (PBS) and 20% pooled human serum. The hydrophilic surface (PAAm) had significantly less nonspecific adhesion of bacteria than that in the control (PET) and other surfaces, when cultured in PBS (P < 0.0001). Charged surfaces, both anionic and cationic, had increased adhesion and aggregation of bacteria in comparison with the control (PET) in the presence of serum proteins over 24 hours (P < 0.0001). Bacteria cultured in serum on the charged surfaces did not have significantly different amounts of biofilm formation compared with that of the control (PET) surface after 48 hours. This study showed that biomaterial surface chemistry characteristics impact initial adhesion and aggregation of S. epidermidis on biomaterials. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Overexpression of regucalcin enhances glucose utilization and lipid production in cloned rat hepatoma H4‐II‐E cells: Involvement of insulin resistance
Authors: Nakashima Chikage , Yamaguchi Masayoshi 
Published: July 2006

AbstractThe role of regucalcin, which is a regulatory protein in intracellular signaling pathway, in the regulation of glucose utilization and lipid production was investigated using the cloned rat hepatoma H4‐II‐E cells overexpressing regucalcin. The hepatoma cells (wild‐type) and stable regucalcin/pCXN2‐transfected cells (transfectant) were cultured for 72 h in a medium containing 10% fetal bovine serum (FBS) to obtain subconfluent monolayers. Cells with subconfluency were cultured for 24 or 72 h in medium containing either vehicle or insulin (10−8 or 10−7 M) with or without supplementation of glucose (10, 25, or 50 mg/ml of medium) in the absence of insulin. The production of triglyceride and free fatty acid was significantly increased in transfectants cultured without insulin and glucose supplementation as compared with that of wild‐type cells. The supplementation of glucose (10, 25, or 50 mg/ml) caused a remarkable increase in medium glucose consumption, triglyceride, and free fatty acid productions in transfectants cultured without insulin. The presence of insulin (10−7 M) caused a significant increase in medium glucose consumption, triglyceride, and free fatty acid productions in wild‐type cells cultured with glucose supplementation. These increases were significantly prevented in transfectants cultured for 72 h. The expression of acetyl‐CoA carboxylase, HMG‐CoA reductase, glucokinase, pyruvate kinase, and glyceroaldehyde‐3‐phosphate dehydrogenase (G3PDH) mRNAs in wild‐type cells was not significantly changed by culture with or without glucose supplementation in the presence of insulin. These gene expressions were not significantly changed in transfectants. The expression of glucose transporter 2 mRNA was significantly increased in transfectants as compared with that of wild‐type cells. Such an increase was not seen in transfectants cultured in the presence of insulin with or without glucose supplementation. This study demonstrates that overexpression of regucalcin enhances glucose utilization and lipid production in the cloned rat hepatoma H4‐II‐E cells, and that it regulates the effect of insulin. J. Cell. Biochem. 99: 1582–1592, 2006. © 2006 Wiley‐Liss, Inc.
Calcium‐pH Crosstalks in the human mast cell line HMC‐1: Intracellular alkalinization activates calcium extrusion through the plasma membrane Ca2+‐ATPase
Authors: Pernas‐Sueiras Octavio , Alfonso Amparo , Vieytes Mercedes R. , Orfao Alberto , Escribano Luis , Francisca Sánchez‐Jiménez , Botana Luis M. 
Published: July 2006

AbstractThe human mast cell line (HMC‐1) has been used to study the relationship between intracellular pH and cytosolic calcium (Ca2+) in mast cells. Thapsigargin (TG) caused store‐operated Ca2+ entry, that is enhanced by the PKC activator PMA. NH4Cl‐induced alkalinization showed an inhibitory effect on TG‐sensitive stores depletion (not on TG‐insensitive stores), and also on final cytosolic Ca2+ levels reached in response to both TG and the ionophore ionomycin. Loperamide, a positive modulator of store‐operated channels, induced a slight Ca2+ entry by itself, and also increased TG‐induced Ca2+ entry. This enhancement was not enough to reverse the inhibitory effect of NH4Cl‐induced alkalinization. When comparing the effect of NH4Cl‐induced alkalinization on Ca2+ levels, with those observed using Ca2+ channel blockers (namely Ni2+ and SKF‐96365), cytosolic profiles for this ion are different, either in modified saline solution or in HCO‐free medium. Thus, it seems unlikely that the inhibitory effect of NH4Cl‐induced alkalinization on Ca2+ is taking place by blockage of Ca2+ entry. Furthermore, inhibition of the plasma membrane Ca2+‐ATPase (an important mechanism for Ca2+ efflux) with sodium orthovanadate (SO) matches with the inhibition of the negative effect on Ca2+ levels elicited by NH4Cl. Data indicate that NH4Cl‐induced alkalinization might be activating Ca2+ efflux from the cell, by stimulation of the plasma membrane Ca2+‐ATPase, and also confirm our previous finding that Ca2+ is a secondary signal to activate HMC‐1 cells. J. Cell. Biochem. 99: 1397–1408, 2006. © 2006 Wiley‐Liss, Inc.