bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteomic analysis of cartilage‐ and bone‐associated samples
Authors: Lammi Mikko J. , Häyrinen Jukka , Mahonen Anitta 
Published: June 2006

AbstractThe skeleton of the human body is built of cartilage and bone, which are tissues that contain extensive amounts of extracellular matrix (ECM). In bone, inorganic mineral hydroxyapatite forms 50–70% of the whole weight of the tissue. Although the organic matrix of bone consists of numerous proteins, 90% of it is composed of type I collagen. In cartilage, ECM forms a major fraction of the tissue, type II collagen and aggrecans being the most abundant macromolecules. It is obvious that the high content of ECM components causes analytical problems in the proteomic analysis of cartilage and bone, analogous to those in the analysis of low‐abundance proteins present in serum. The massive contents of carbohydrates present in cartilage proteoglycans, and hydroxyapatite in bone, further complicate the situation. However, the development of proteomic tools makes them more and more tempting also for research of musculoskeletal tissues. Application of proteomic techniques to the research of chondrocytes, osteoblasts, osteocytes, and osteoclasts in cell cultures can immediately benefit from the present knowledge. Here we make an overview to previous proteomic research of cartilage‐ and bone‐associated samples and evaluate the future prospects of applying proteomic techniques to investigate key events, such as cellular signal transduction, in cartilage‐ and bone‐derived cells.
The Science of “Fingerprinting” Bees
Authors: Steinhage Volker , Schröder Stefan , Roth Volker , Cremers Armin B. , Drescher Wilhelm , Wittmann Dieter 
Published: June 2006

AbstractThe ABIS system allows the rapid and accurate identification of bee species. This process is based on automatic image analysis of the bee's wings and enables the development of new, computer‐aided methods to identify the bee species
The Turbulent Birth of a Star
Authors: Jappsen Anne‐Katharina , Schmeja Stefan , Klessen Ralf Stephan 
Published: June 2006

AbstractThe birth of a star is a dramatic process, about which there are many unanswered questions for astrophysicists. Researchers are now using computer simulations to shed light on the mechanisms which cause the gas in the Milky Way to form a star such as our own sun
A joint model for the term structure of interest rates and the macroeconomy
Authors: Dewachter Hans , Lyrio Marco , Maes Konstantijn 
Published: June 2006

AbstractWe present and estimate a continuous time term structure model that incorporates observable macroeconomic variables and latent variables with a clear macroeconomic interpretation. Our model is able to accurately describe the joint dynamics for US macroeconomic variables and the yield curve. However, the observable variables do not explain the long end of the term structure. Central tendencies of these macroeconomic variables do a much better job in this respect. These unobservable factors also play an important role in the description of the interest rate policy rule. Both observable and non‐observable factors determine the risk premia and hence bond excess holding returns. Copyright © 2006 John Wiley & Sons, Ltd.
Estimating an economic model of crime using panel data from North Carolina
Authors: Baltagi Badi H. 
Published: June 2006

AbstractThis paper replicates the Cornwell and Trumbull (1994) estimation of a crime model using panel data on 90 counties in North Carolina over the period 1981–1987. While the Between and Within estimates are replicated, the fixed effects 2SLS as well as the 2SLS estimates are not. In fact, the fixed effects 2SLS estimates turn out to be insignificant for all important deterrent variables as well as legal opportunity variables. We argue that the usual Hausman test, based on the difference between fixed effects and random effects, may lead to misleading inference when endogenous variables of the conventional simultaneous equation type are among the regressors. We estimate the model using random effects 2SLS and perform a Hausman test based on the difference between fixed effects 2SLS and random effects 2SLS. We cannot reject the consistency of the random effects 2SLS estimator and this estimator yields plausible and significant estimates of the crime model. This result should be tempered by the legitimacy of the chosen instruments. Copyright © 2006 John Wiley & Sons, Ltd.
Modified aminosilane substrates to evaluate osteoblast attachment, growth, and gene expression in vitro
Authors: Siperko L.M. , Jacquet R. , Landis W.J. 
Published: June 2006

AbstractBone cell‐substrate interactions are important to understand in the design, selection, and surface modification of bone implants. To gain insight into such interactions, substrates designed with surface species approximating the physiological environment of bone matrix were studied. Osteoblasts (Ob) grown on three such surfaces were used to evaluate cell‐substrate effects on attachment, growth, and gene expression as compared with controls. Initial surface preparation consisted of coating glass slides with aminopropyltriethoxy silane (APTES), after which the coated slides were modified with collagen‐rich extracellular matrix components obtained from normally mineralizing avian tendon: the tripeptide arginine–glycine–aspartic acid (arg–gly–asp), or a precipitate formed from a metastable solution containing inorganic ions normally found in blood (simulated body fluid). Each of the modified substrates, as well as the nonmodified (APTES) control, provided distinctly different physical (evidenced by differences in rms roughness) and chemical surfaces for seeding primary osteoblasts obtained from 14‐day‐old normal embryonic chickens. Cell responses to each of the substrates were evaluated over a 21‐day period in terms of Ob growth and growth rate, alkaline phosphatase (ALP) activity, and gene expression of type I collagen (COL I), osteopontin (OPN), osteocalcin (OC), and bone sialoprotein (BSP). From these preliminary experiments, indications are that cell attachment and growth in this study possibly are independent processes, an assumption that compels the need for further studies. Collagen‐rich matrix‐modified substrates had a distinct advantage over others when cell growth rate, ALP activity, and gene expression were considered; cells on these substrates exhibited increased ALP activity and enhanced expression of BSP, OPN, and OC when compared with those of cells on APTES controls or other modified substrates. These results indicate that matrix‐modified substrates such as those used in this study provide favorable templates for tissue generation, suggesting their potential in the design of surfaces for bone implants. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Characterization of DNA release from composites of oligo(poly(ethylene glycol) fumarate) and cationized gelatin microspheres in vitro
Authors: Kasper F. Kurtis , Jerkins Erin , Tanahashi Kazuhiro , Barry Michael A. , Tabata Yasuhiko , Mikos Antonios G. 
Published: June 2006

AbstractThis research investigates the release of plasmid DNA from novel hydrogel composites of oligo(poly(ethylene glycol) fumarate) (OPF) and cationized gelatin microspheres (CGMS), as well as the swelling and degradation of these materials in vitro. The release of total DNA and of double‐stranded DNA was measured fluorescently, and the swelling properties and polymer mass loss of the hydrogels were assessed. Further, the structural integrity of the released DNA was determined through electrophoresis. It was found that plasmid DNA can be released in a sustained fashion over the course of up to 49–140 days in vitro from hydrogels of OPF synthesized from poly(ethylene glycol) of nominal molecular weights of 10 kDa and 3 kDa, respectively, with the release kinetics depending upon the material composition and the method of DNA loading. Released DNA was predominately double‐stranded DNA (dsDNA) in structure and of the open‐circular conformation. The results suggest that DNA release from hydrogel composites of OPF and CGMS is dominated by the degradation of the OPF component of the gels. Electrophoresis results indicate that the released DNA retains suitable conformation for potential bioactivity over the course of at least 63 days of release. Thus, these studies demonstrate the potential of composites of OPF and CGMS in controlled gene delivery applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
In vitro homogeneous and heterogeneous degradation of poly(ϵ‐caprolactone/polyethylene glycol/L‐lactide): The absence of autocatalysis and the role of enzymes
Authors: Wang Zhaoxu , Wang Shenguo , Guidoin Robert , Marois Yves , Zhang Ze 
Published: June 2006

AbstractThis study investigated the in vitro degradation behavior of poly(ϵ‐caprolactone/polyethylene glycol/L‐lactide) (PCEL) in comparison with that of three other biodegradable polymers. Polymer membranes were incubated in pancreatin solution, Ringer's solution, and distilled water at 37°C for up to 20 weeks. Characterization involved measuring weight loss, observing the morphological changes by scanning electron microscopy (SEM), analyzing molecular weight using size exclusion chromatography (SEC), and studying the crystalline structure using differential scanning calorimetry (DSC). The hydrolysis in a simple aqueous solution experienced no autocatalysis, which was attributed to the high permeability of PCEL to water‐soluble degradation products. Similar degradation rates were recorded for the PCEL and poly(L,L‐lactide) (PLLA) test membranes. In the presence of pancreatin, the PCEL membrane experienced rapid heterogeneous surface erosion likely caused by the selective loss of its surface PEG components under enzymatic action. Pancreatin also substantially increased the even physical resorption of the other test polymers by eliminating autocatalysis. This study demonstrated that autocatalysis commonly experienced by poly(α‐hydroxyl acid) can be reduced through chemical formulation or high enzyme activity. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Activation of ERK signaling upon alternative protease nexin‐1 internalization mediated by syndecan‐1
Authors: Li Xiaobiao , Herz Joachim , Monard Denis 
Published: June 2006

AbstractProtease nexin‐1 (PN‐1), an inhibitor of serine proteases, contributes to tissue homeostasis and influences the behavior of some tumor cells. The internalization of PN‐1 protease complexes is considered to be mediated by the low‐density lipoprotein receptor related protein 1 (LRP1). In this study, both wild‐type and LRP1−/− mouse embryonic fibroblasts (MEF) were shown to internalize PN‐1. Receptor associated protein (RAP) interfered with PN‐1 uptake only in wild‐type MEF cells, indicating that another receptor mediates PN‐1 uptake in the absence of LRP1. In LRP1−/− MEF cells, inhibitor sensitivity and kinetic values (t1/2 at 45 min) of PN‐1 uptake showed a similarity to syndecan‐1‐mediated endocytosis. In these cells, PN‐1 uptake was increased by overexpression of full‐length syndecan‐1 and decreased by RNA interference targeting this proteoglycan. Most important, in contrast to PKA activation known to be triggered by LRP1‐mediated internalization, our study shows that syndecan‐1‐mediated internalization of PN‐1 stimulated the Ras‐ERK signaling pathway. J. Cell. Biochem. 99: 936–951, 2006. © 2006 Wiley‐Liss, Inc.
Differential expression of tropomyosin during segmental heart development in Mexican axolotl
Authors: Zajdel Robert W. , McLean Matthew D. , Denz Christopher R. , Dube Syamalima , Thurston Harold L. , Poiesz Bernard J. , Dube Dipak K. 
Published: June 2006

AbstractThe Mexican axolotl, Ambystoma mexicanum, serves as an intriguing model to investigate myofibril organization and heart development in vertebrates. The axolotl has a homozygous recessive cardiac lethal gene “c” which causes a failure of ventricular myofibril formation and contraction. However, the conus of the heart beats, and has organized myofibrils. Tropomyosin (TM), an essential component of the thin filament, has three known striated muscle isoforms (TPM1α, TPM1κ, and TPM4α) in axolotl hearts. However, it is not known whether there are differential expression patterns of these tropomyosin isoforms in various segments of the heart. Also, it is not understood whether these isoforms contribute to myofibril formation in a segment‐specific manner. In this study, we have utilized anti‐sense oligonucleotides to separately knockdown post‐transcriptional expression of TPM1α and TPM4α. We then evaluated the organization of myofibrils in the conus and ventricle of normal and cardiac mutant hearts using immunohistochemical techniques. We determined that the TPM1α isoform, a product of the TPM1 gene, was essential for myofibrillogenesis in the conus, whereas TPM4α, the striated muscle isoform of the TPM4 gene, was essential for myofibrillogenesis in the ventricle. Our results support the segmental theory of vertebrate heart development. J. Cell. Biochem. 99: 952–965, 2006. © 2006 Wiley‐Liss, Inc.
Growth of choroid plexus epithelium vesicles in vitro depends on secretory activity
Authors: Swetloff Adam , Greenwood Sarah , Wade Angela M. , Ferretti Patrizia 
Published: June 2006

AbstractAlthough a number of models have been used to study choroid plexus epithelium (CPe) function, analysis in physiological conditions of this polarised epithelium which produces the majority of the cerebrospinal fluid (CSF) and is one of the key barriers between blood and CSF in the brain remains challenging. As CPe cells form polarised CPe vesicles when cultured in Matrigel, we have assessed their behaviour and potential use for pharmacological studies. Like CPe cells in vivo, CPe vesicles express transthyretin, E2f5, Fox‐j1 and p73, and contain tight junctions, as indicated by ZO‐1 expression and electron microscopy analysis. Time‐lapse microscopy shows that CPe cells plated in Matrigel are highly migratory and rapidly form homotypic cell aggregates, which then reorganise to form vesicles whose size increases linearly over time. Neither aggregate nor vesicle size is affected by AraC treatment, though this inhibitor significantly reduces proliferation in CPe monolayers. Increase in size of vesicles, which have reached a growth plateau is observed following addition of fluorescently‐labelled CPe cells, which become incorporated into the vesicle walls. Significantly, treatment with secretion inhibitors blocks vesicle formation and their expansion. These results show that secretion, rather than cell division, controls vesicle growth, consistent with low levels of proliferation and thinning of the CPe observed both in growing vesicles and during CPe development. Therefore, changes in vesicle size can be used to evaluate the effect of putative molecules involved in the regulation of secretion. J. Cell. Physiol. 208: 549–555, 2006. © 2006 Wiley‐Liss, Inc.
Re‐evaluation of the distinction between type I and type II cells: The necessary role of the mitochondria in both the extrinsic and intrinsic signaling pathways upon fas receptor activation
Authors: Tafani Marco , Karpinich Natalie O. , Serroni Ada , Russo Matteo A. , Farber John L. 
Published: June 2006

AbstractCyclosporin A (CyA) and bongkrekic acid (BK) prevented Fas‐induced apoptosis in two type I cell lines (H9 and SKW6.4) and two type II cell lines (Jurkat and CEM). CyA and BK inhibited the release of cytochrome c in all four cell lines. In type I cells and in CEM cells, CyA and BK did not prevent the translocation of Bax to the mitochondria. In these same cells, full‐length Bid decreased in the mitochondria and cytosol. The cleavage product of Bid, tBid, appeared in the cytosol and to a lesser extent in the mitochondria. In Jurkat cells, Bid also decreased in the cytosol, but increased in the mitochondria. Similar to the other cells, tBid appeared in the mitochondria and cytosol. In the type I H9 and SKW6.4 cells and type II Jurkat cells, the caspase‐8 inhibitor Z‐Ile‐Glu(OMe)‐Thr‐Asp(OMe)‐CH2F (IETD) prevented the cell killing. In the type I cells, IETD prevented the translocation of Bax, the degradation of Bid and the accumulation of tBid. By contrast, IETD only marginally protected the type II CEM cells. In these cells in the presence of IETD, Bax translocated to the mitochondria, in the absence of any degradation of Bid or accumulation of tBid. In the type I H9 cells, IETD produced a depletion of ATP, an effect that did not occur in the type II CEM cells. It is concluded that in type I cells the extrinsic signaling pathway is mitochondrial dependent to the same extent as is the intrinsic pathway in type II cells. J. Cell. Physiol. 208: 556–565, 2006. © 2006 Wiley‐Liss, Inc.
Regulation of phosphatidylinositol 3‐kinase (PI3K)/Akt and nuclear factor‐kappa B signaling pathways in dystrophin‐deficient skeletal muscle in response to mechanical stretch
Authors: Dogra Charu , Changotra Harish , Wergedal Jon E. , Kumar Ashok 
Published: June 2006

AbstractPhosphatidylinositol 3‐kinase (PI3K)/Akt and nuclear factor‐kappa B (NF‐κB) signaling pathways play a critical role in mediating survival signals. In this study we have investigated how loss of dystrophin (the primary cause of Duchenne muscular dystrophy) modulates the activation of PI3K/Akt and NF‐κB signaling pathways in skeletal muscle in response to mechanical stimulation. Activation of Akt was significantly higher in diaphragm muscle from dystrophin‐deficient mdx mice compared to normal mice at both prenecrotic and necrotic states. Higher activation of Akt was also observed in cultured dystrophin‐deficient primary myotubes differentiated in vitro. Application of passive mechanical stretch ex vivo synergistically increased the activation of Akt in diaphragm of mdx mice. Stretch‐induced activation of PDK‐1 and PI3K were also higher in diaphragm of mdx mice compared to normal mice. Pretreatment of diaphragm with PI3K inhibitor LY294002 blocked the activation of Akt in normal and mdx mice. Higher activation of Akt was associated with increased phosphorylation of its downstream targets glycogen synthase kinase 3β (GSK3β), FKHR, and mammalian target of rapamycin (mTOR). Treatment of diaphragm muscle with LY294002 inhibited the stretch‐induced activation of IkappaB (IκB) kinase (IKK) and NF‐κB transcription factor in normal and mdx mice. Mechanical stretch also reduced the interaction of HDAC1 with RelA subunit of NF‐κB in diaphragm muscle. Finally, cellular levels of Bcl‐2, cIAP1, and integrin β1 and activation of integrin linked kinase were higher in diaphragm muscle of mdx mice compared to normal mice. Taken together, our data suggest that loss of dystrophin and/or mechanical stretch results in the up‐regulation of PI3K/Akt and NF‐κB signaling pathways in skeletal muscle. J. Cell. Physiol. 208: 575–585, 2006. © 2006 Wiley‐Liss, Inc.
ATR dependent activation of Chk2
Authors: Wang Xiao Qi , Redpath J. Leslie , Fan Sheung Tat , Stanbridge Eric J. 
Published: June 2006

AbstractATM and ATR are essential regulators of DNA damage checkpoints in mammalian cells through their respective effectors, Chk2 and Chk1. Cross regulation of the ATM‐Chk2 and ATR‐Chk1 pathways is very limited, although ATM and ATR show overlapping function in a partnership and time‐dependent manner. In this study, we report that Chk2 is a substrate of ATR in response to ionizing and ultraviolet radiation. ATR activation induced by ionizing radiation (IR) is weak in ATM+/+ cells. However, when ATM is inhibited by caffeine, ATR activation is markedly enhanced. Total Chk2 and Chk2 Thr68 are also hyperphosphorylated in the presence of caffeine. Both ATM+/+ and ATM−/− cells display normal ATR activation in response to UV radiation‐induced DNA damage, which is caffeine sensitive. In two lines of ATM‐deficient, as well as in an ATM siRNA silencing cell line, ATR is activated when the cells are exposed to IR and is able to phosphorylate Chk2 in vitro. These observations suggest that ATR is one of the kinases that is likely involved in phosphorylation of Chk2 in response to IR when ATM is deficient. J. Cell. Physiol. 208: 613–619, 2006. © 2006 Wiley‐Liss, Inc.
Nucleotide receptors stimulation by extracellular ATP controls Hsp90 expression through APE1/Ref‐1 in thyroid cancer cells: A novel tumorigenic pathway
Authors: Pines Alex , Bivi Nicoletta , Vascotto Carlo , Romanello Milena , D'Ambrosio Chiara , Scaloni Andrea , Damante Giuseppe , Morisi Roberta , Filetti Sebastiano , Ferretti Elisabetta , Quadrifoglio Franco , Tell Gianluca 
Published: June 2006

AbstractNucleotide receptors signaling affects cell proliferation, with possible implications on tumorigenic processes. However, molecular targets and action mechanisms of the extracellular nucleotides are still poorly elucidated. We have previously shown in ARO cells that APE1/Ref‐1, a transcriptional coactivator responsible for the maintenance of the cellular proliferative rate, is functionally controlled by P2‐mediated signaling. Here, we demonstrate that extracellular ATP has a mitogenic effect on ARO cells, increasing ERK phosphorylation, AP1 activation, and cyclin D1 expression. Using the ATP/ADPase apyrase and the P2 receptor antagonist suramin, we show that the extracellular ATP, physiologically released by ARO cells, exerts mitogenic effects. A differential proteomic approach was used to identify molecular events associated with the ATP‐induced cell proliferation. Among other proteins, Hsp90 was found upregulated upon ATP stimulation. Pretreatment with suramin completely blocked the ATP‐induced Hsp90 activation, confirming the involvement of cell‐surface P2 nucleotide receptors in the ATP‐mediated activation of ARO cells. Treatment of proliferating ARO cells with suramin and apyrase significantly reduced the intracellular levels of Hsp90, suggesting an autocrine/paracrine mechanism of control on Hsp90 expression by extracellular ATP. The influence of Hsp90 on ATP‐induced cell proliferation was also demonstrated by its specific inhibition with 17‐AAG. The molecular pathway by which ATP stimulates cell proliferation was further investigated by siRNA strategies showing that Hsp90 is a target of APE1/Ref‐1 functional activation. Stimulation of ARO cells with specific nucleotide receptors agonists evidenced a major involvement of P2Y1and P2Y2receptors in controlling the Hsp90 activation. Accordingly, these two receptors resulted significantly upregulated in sample biopsies from different thyroid tumors. J. Cell. Physiol. 209: 44–55, 2006. © 2006 Wiley‐Liss, Inc.
Suppression of Cell and Platelet Adhesion to Star‐Shaped 8‐Armed Poly(ethylene glycol)‐Poly(L‐lactide) Block Copolymer Films
Authors: Nagahama Koji , Ohya Yuichi , Ouchi Tatsuro 
Published: June 2006

AbstractSummary: To explore the potential of a star‐shaped 8‐armed poly(ethylene glycol)35K‐block‐poly(L‐lactide)37K (8‐armed PEG35K‐b‐PLLA37K: $\overline M _{\rm n}$ of PEG = 35 000, $\overline M _{\rm n}$ of PLLA = 37 000) film as a novel bioabsorbable adhesion‐prevention membrane, the water structure, surface contact angle, protein adsorption, and cell and platelet anti‐adhesion properties of such a hydrated film are investigated. Based on the results, it is found that the 8‐armed PEG35K‐b‐PLLA37K film exhibits a biologically inert surface, which is the result of a large number of PEG chains and a free water layer on the film surface. This leads to a reduction in protein absorption and cell and platelet adhesion onto the film surface. This implies that the star‐shaped 8‐armed PEG35K‐b‐PLLA37K film can be utilized as a novel bioabsorbable adhesion‐prevention membrane.A schematic presentation of the protein adsorption, platelet adhesion, and cell attachment phenomena for the 8‐armed PEG‐b‐PLLA films.magnified imageA schematic presentation of the protein adsorption, platelet adhesion, and cell attachment phenomena for the 8‐armed PEG‐b‐PLLA films.