bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chitosan implants in the rat spinal cord: Biocompatibility and biodegradation
Authors: Kim Howard , Tator Charles H. , Shoichet Molly S. 
Published: April 2011

AbstractBiomaterials are becoming increasingly popular for use in spinal cord repair, but few studies have investigated their long‐term biocompatibility in central nervous system tissue. In this study, chitosan was compared with two commercial materials, degradable polyglycolide (vicryl and polyglactin 910) and nondegradable expanded poly(tetrafluoroethylene) (Gore‐Tex and ePTFE), in terms of host tissue response and biodegradation in the rat spinal cord in two different spinal cord implantation models. In an uninjured model, implants were placed in the spinal cord intrathecal space for up to 6 months. At 1 month, vicryl implants elicited an elevated macrophage/microglia response compared to chitosan and Gore‐Tex, which subsided in all groups by 6 months. Fibrous encapsulation was observed for all three materials. At 6 months, the in vivo degradation of vicryl was complete, while Gore‐Tex showed no signs of degradation, as assessed by mass loss and SEM. Chitosan implants showed evidence of chain degradation at 6 months as demonstrated by differential hematoxylin and eosin staining; however, this did not result in mass loss. In the second model, implants were placed directly into the spinal cord for up to 12 months. This resulted in increased immune and inflammatory responses but did not alter degradation profiles. The same trends observed for the materials in the intrathecal space were mirrored in the spinal cord tissue. These results demonstrate that chitosan is a relatively inert biomaterial that does not elicit a chronic immune response and is suitable for long‐term applications for repair of the spinal cord. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Three‐dimensional glass‐derived scaffolds for bone tissue engineering: Current trends and forecasts for the future
Authors: Baino Francesco , Vitale‐Brovarone Chiara 
Published: April 2011

AbstractBiomaterials used in regenerative medicine are often designed to act as 3D porous templates (scaffolds) able to support and promote the growth and repair of natural tissues. Some types of glasses have a great potential for making bone tissue engineering scaffolds, as they can bond to host bone, stimulate bone cells toward osteogenesis, and resorb at the same time as the bone is repaired. This review article highlights the evolution of glass‐based scaffolds for bone tissue engineering; specifically, the features, limitations, and advantages of the different types of glass‐derived scaffolds proposed in the literature (macroporous glass‐ceramic, sol–gel glass, composite, graded, hybrid, and hierarchical implants) are critically examined, discussed, and compared. Future directions for the research are also suggested, highlighting the promise of multifunctional systems able to combine bone regeneration and drug release abilities, the increasing role of nondestructive advanced imaging techniques, such as X‐ray microtomography, for scaffolds investigation and the potential of stem cells incorporation into scaffolds. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Efficiency of random search procedures along the silicon cluster series: Sin (n = 5–10, 15, and 20)
Authors: Avaltroni Fabrice , Corminboeuf Clemence 
Published: April 2011

AbstractThe efficiency of the simplest isomeric search procedure consisting in random generation of sets of atomic coordinates followed by density functional theory geometry optimization is tested on the silicon cluster series (Si5–
10,
15,
20). Criteria such as yield, isomer distributions and recurrences are used to clearly establish the performance of the approach with respect to increasing cluster size. The elimination of unphysical candidate structures and the use of distinct box shapes and theoretical levels are also investigated. For the smaller Sin (n = 5–10) clusters, the generation of random coordinates within a spherical box is found to offer a reasonable alternative to more complex algorithms by allowing straightforward identification of every known low‐lying local minima. The simple stochastic search of larger clusters (i.e. Si15 and Si20) is however complicated by the exponentially increasing number of both low‐ and high‐lying minima leading to rather arbitrary and non‐comprehensive results. © 2011 Wiley Periodicals, Inc. J Comput Chem 2011
The effect of iron and copper impurities on the wettability of sphalerite (110) surface
Authors: Simpson Darren J. , Bredow Thomas , Chandra Anand P. , Cavallaro Giuseppe P. , Gerson Andrea R. 
Published: April 2011

AbstractThe effect of impurities in the zinc sulfide mineral sphalerite on surface wettability has been investigated theoretically to shed light on previously reported conflicting results on sphalerite flotation. The effect of iron and copper impurities on the sphalerite (110) surface energy and on the water adsorption energy was calculated with the semi‐empirical method modified symmetrically orthogonalized intermediate neglect of differential overlap (MSINDO) using the cyclic cluster model. The effect of impurities or dopants on surface energies is small but significant. The surface energy increases with increasing surface iron concentration while the opposite effect is reported for increasing copper concentration. The effect on adsorption energies is much more pronounced with water clearly preferring to adsorb on an iron site followed by a zinc site, and copper site least favorable. The theoretical results indicate that a sphalerite (110) surface containing iron is more hydrophilic than the undoped zinc sulfide surface. In agreement with the literature, the surface containing copper (either naturally or by activation) is more hydrophobic than the undoped surface. © 2011 Wiley Periodicals, Inc. J Comput Chem 2011
Being homeless and the use and nonuse of services: a qualitative study
Authors: Ogden Jane , Avades Talin 
Published: April 2011

AbstractEight homeless people were interviewed about their experiences of health and social services. Three themes emerged: responsibility, identity, and feeling trapped. Although some felt they were responsible for their own situation and avoided help, most turned to formal channels for help, but professionals were often seen as offering unwanted labels and as being rule bound. In contrast, peers were considered more understanding but colluded with their problems. Participants also expressed feeling trapped within the homeless system. Therefore, by locating responsibility for change with others, they were left feeling stigmatized, but by turning to their peers, their situation remained the same. © 2011 Wiley Periodicals, Inc.
Limiting attrition in longitudinal research on homeless adolescents: what works best?
Authors: Hobden Karen , Curtis Forney Jason , Wyszacki Durham Kathleen , Toro Paul 
Published: April 2011

AbstractThe effectiveness of five tracking strategies (collateral contacts, Internet databases, driver's records, letters, and community visits) used in attempting to locate homeless and housed adolescents 4.5 years after they were first contacted was examined and compared. The study sample comprised 401 adolescents (252 homeless and 149 matched housed) from 8 counties in Southeast Michigan. Homelessness was defined as sleeping in a shelter, at a friend's home without parental permission, or on the streets for at least 1 night within 1 month before initial contact. We successfully located and interviewed 85% (n=340) of our sample at the 4.5‐year time point. The most effective tracking procedure was collateral contact, which was important in locating 43% of participants in this study, followed by Internet databases (18%), community visits (11%), driver's records (6%), and letters (6%). © 2011 Wiley Periodicals, Inc.
TRAIL up‐regulation must be accompanied by a reciprocal PKCε down‐regulation during differentiation of colonic epithelial cell: Implications for colorectal cancer cell differentiation
Authors: Gobbi Giuliana , Di Marcantonio Daniela , Micheloni Cristina , Carubbi Cecilia , Galli Daniela , Vaccarezza Mauro , Bucci Giovanna , Vitale Marco , Mirandola Prisco 
Published: April 2011

AbstractPKC isoenzymes play central roles in various cellular signalling pathways, participating in a variety of protein phosphorylation cascades that regulate/modulate cellular structure and gene expression. It has been firmly established that several isoforms of PKC have a role in the regulation of tumor necrosis factor‐related apoptosis inducing ligand (TRAIL) activity. Our interest in probing the role of the epsilon isoform of PKC in the colonic cell differentiation stems from the discovery that PKCε and TRAIL are involved in the differentiation of other cell types like hematopoietic stem cells. Although the role of PKCε and TRAIL in the gastrointestinal system is unclear, it has been observed that PKCε has oncogenic activity in colon epithelial cells (CEC), while TRAIL increases the death of intestinal epithelial cells during inflammation. Here we demonstrate a reciprocal expression of PKCε and TRAIL in human colon mucosa: CECs at the bottom of the colonic crypts show high levels of PKCε, being negative for TRAIL expression. On the contrary, luminal CECs are positive for TRAIL, while negative for PKCε. Indeed, TRAIL‐ and butyrate‐induced differentiation of the human colorectal cancer cell line HT29 requires the decrease of PKCε expression, whose absence in turn increases cell sensitivity to TRAIL‐induced apoptosis. Moreover, TRAIL preferentially promotes HT29 differentiation into goblet cells. Taken together, this data demonstrate that TRAIL and PKCε must be reciprocally regulated to ensure physiological CEC differentiation starting from the stem cell pool, and that the down‐regulation of PKCε is however critical for the differentiation and apoptosis of cancer cells. J. Cell. Physiol. 227: 630–638, 2012. © 2011 Wiley Periodicals, Inc.
Emerging strategies for the early detection and prevention of head and neck squamous cell cancer
Authors: Dasgupta Santanu , Dash Rupesh , Das Swadesh K. , Sarkar Devanand , Fisher Paul B. 
Published: April 2011

AbstractDespite significant improvements in therapeutic protocols, head and neck squamous cell carcinoma (HNSCC) remains a major health problem worldwide. The 5‐year post‐therapeutic survival rate is among the lowest of the major cancers with loco‐regional relapse being the main cause of death. Moreover, in most instances, the quality of life of the afflicted patient is severely compromised. The poor prognosis for HNSCC is primarily due to disease detection at advanced stages. Accordingly, development of early detection and preventive strategies are essential. Recent advances in our understanding of the molecular biology and etiology of HNSCC should facilitate development of improved intervention and therapeutic approaches. The present review discusses the potential role of such factors for developing preventive and early diagnostic strategies for HNSCC management. J. Cell. Physiol. 227: 467–473, 2012. © 2011 Wiley Periodicals, Inc.
The roles of integrin β4 in Vascular Endothelial Cells
Authors: Wang Li , Dong ZhiWu , Zhang Yun , Miao JunYing 
Published: April 2011

AbstractIntegrin heterodimers play diverse and important roles in physiological and pathological processes, such as cell adhesion, migration, proliferation, differentiation, angiogenesis, and tumor progression, via the outside‐in and/or inside‐out signaling pathways. Aberrant functions of integrins have been implicated in the causation and intervention of multiple diseases. Integrin β4, a laminin‐5 (LN5) receptor, mainly locates in the adhesion structure of hemidesmosome (HD). Most of the previous researches concentrated on the role of integrin β4 in cancer and cancer therapy, and a few focused on the physiological roles of normal mammalian cells. Recently, accumulating data reveal that integrin β4 participates in cell death, macroautophagy (hereafter autophagy), senescence, and differentiation regulations in various cell types including human umbilical vein endothelial cells (HUVECs), mesenchymal stem cells, and mouse neural cells, implying the key roles of integrin β4 in the physiological alteration of mammalian cells. Thus, the elucidation of integrin β4‐mediated signaling may undoubtedly contribute to novel therapeutic strategies for various human diseases, such as vascular and neural disorders. We have reviewed the roles of integrin β4 in neural cells. In the present review we will discuss the recent research progress in the inherent functions and pharmacological modulation of integrin β4 in vascular endothelial cells. J. Cell. Physiol. 227: 474–478, 2012. © 2011 Wiley Periodicals, Inc.
Nuclear γ‐tubulin associates with nucleoli and interacts with tumor suppressor protein C53
Authors: Hořejší Barbora , Vinopal Stanislav , Sládková Vladimíra , Dráberová Eduarda , Sulimenko Vadym , Sulimenko Tetyana , Vosecká Věra , Philimonenko Anatoly , Hozák Pavel , Katsetos Christos D. , Dráber Pavel 
Published: April 2011

Abstractγ‐Tubulin is assumed to be a typical cytosolic protein necessary for nucleation of microtubules from microtubule organizing centers. Using immunolocalization and cell fractionation techniques in combination with siRNAi and expression of FLAG‐tagged constructs, we have obtained evidence that γ‐tubulin is also present in nucleoli of mammalian interphase cells of diverse cellular origins. Immunoelectron microscopy has revealed γ‐tubulin localization outside fibrillar centers where transcription of ribosomal DNA takes place. γ‐Tubulin was associated with nucleolar remnants after nuclear envelope breakdown and could be translocated to nucleoli during mitosis. Pretreatment of cells with leptomycin B did not affect the distribution of nuclear γ‐tubulin, making it unlikely that rapid active transport via nuclear pores participates in the transport of γ‐tubulin into the nucleus. This finding was confirmed by heterokaryon assay and time‐lapse imaging of photoconvertible protein Dendra2 tagged to γ‐tubulin. Immunoprecipitation from nuclear extracts combined with mass spectrometry revealed an association of γ‐tubulin with tumor suppressor protein C53 located at multiple subcellular compartments including nucleoli. The notion of an interaction between γ‐tubulin and C53 was corroborated by pull‐down and co‐immunoprecipitation experiments. Overexpression of γ‐tubulin antagonized the inhibitory effect of C53 on DNA damage G2/M checkpoint activation. The combined results indicate that aside from its known role in microtubule nucleation, γ‐tubulin may also have nuclear‐specific function(s). J. Cell. Physiol. 227: 367–382, 2012. © 2011 Wiley Periodicals, Inc.
Lysyl hydroxylase 3 is secreted from cells by two pathways
Authors: Wang Chunguang , Ristiluoma Marja‐Maija , Salo Antti M. , Eskelinen Sinikka , Myllylä Raili 
Published: April 2011

AbstractLysyl hydroxylase 3 (LH3) is a post‐translational modification enzyme with lysyl hydroxylase (LH), collagen galactosyltransferase (GT), and glucosyltransferase (GGT) activities. The active sites responsible for LH and GT/GGT activities of LH3 are localized separately in the carboxy‐ and the amino‐terminal parts of the molecule, respectively. LH3 is found both intracellularly in the ER, as well as extracellularly in serum, the extracellular space and on cell surfaces, and is the only secreted LH isoform. In order to determine whether the activities of LH3 play a role in the secretion, we created various LH3 and mutant expression constructs and over‐expressed the proteins in COS‐7 and HT‐1080 cells. Our data indicate that while the LH active site mediates retention of LH3 in the ER, the GGT active site is required for the secretion of LH3 into the extracellular space. Moreover, Brefeldin A treatment and cholesterol depletion of the cells revealed that the secretion of LH3 from the ER to the extracellular space occurs via two secretory pathways, which generate two glycoforms. LH3 molecules found in the cell medium are secreted through the Golgi complex, and the secretion is dependent on LH3 glycosyltransferase activity. LH3 found on the cell surface bypasses the Golgi complex. J. Cell. Physiol. 227: 668–675, 2012. © 2011 Wiley Periodicals, Inc.
Dynamic redistribution of calcium sensitive potassium channels (hKCa3.1) in migrating cells
Authors: Schwab Albrecht , Nechyporuk‐Zloy Volodymyr , Gassner Birgit , Schulz Christoph , Kessler Wolfram , Mally Sabine , Römer Michael , Stock Christian 
Published: April 2011

AbstractCalcium‐sensitive potassium channels (KCa3.1) are expressed in virtually all migrating cells. Their activity is required for optimal cell migration so that their blockade leads to slowing down. KCa3.1 channels must be inserted into the plasma membrane in order to elicit their physiological function. However, the plasma membrane of migrating cells is subject to rapid recycling by means of endo‐ and exocytosis. Here, we focussed on the endocytic internalization and the intracellular transport of the human isoform hKCa3.1. A hKCa3.1 channel construct with an HA‐tag in the extracellularly located S3‐S4 linker was transfected into migrating transformed renal epithelial MDCK‐F cells. Channel internalization was visualized and quantified with immunofluorescence and a cell‐based ELISA. Movement of hKCa3.1 channel containing vesicles as well as migration of MDCK‐F cells were monitored by means of time lapse video microscopy. hKCa3.1 channels are endocytosed during migration. Most of the hKCa3.1 channel containing vesicles are moving at a speed of up to 2 µm/sec in a microtubule‐dependent manner towards the front of MDCK‐F cells. Our experiments indicate that endocytosis of hKCa3.1 channels is clathrin‐dependent since they colocalize with clathrin adaptor proteins and since it is impaired when a C‐terminal dileucine motif is mutated. The C‐terminal dileucine motif is also important for the subcellular localization of hKCa3.1 channels in migrating cells. Mutated channels are no longer concentrated at the leading edge. We therefore propose that recycling of hKCa3.1 channels contributes to their characteristic subcellular distribution in migrating cells. J. Cell. Physiol. 227: 686–696, 2012. © 2011 Wiley Periodicals, Inc.
Regulation of inositol 1,4,5‐trisphosphate receptor function during mouse oocyte maturation
Authors: Wakai Takuya , Vanderheyden Veerle , Yoon Sook‐Young , Cheon Banyoon , Zhang Nan , Parys Jan B. , Fissore Rafael A. 
Published: April 2011

AbstractAt the time of fertilization, an increase in the intracellular Ca2+ concentration ([Ca2+]i) underlies egg activation and initiation of development in all species studied to date. The inositol 1,4,5‐trisphosphate receptor (IP3R1), which is mostly located in the endoplasmic reticulum (ER) mediates the majority of this Ca2+ release. The sensitivity of IP3R1, that is, its Ca2+ releasing capability, is increased during oocyte maturation so that the optimum [Ca2+]i response concurs with fertilization, which in mammals occurs at metaphase of second meiosis. Multiple IP3R1 modifications affect its sensitivity, including phosphorylation, sub‐cellular localization, and ER Ca2+ concentration ([Ca2+]ER). Here, we evaluated using mouse oocytes how each of these factors affected IP3R1 sensitivity. The capacity for IP3‐induced Ca2+ release markedly increased at the germinal vesicle breakdown stage, although oocytes only acquire the ability to initiate fertilization‐like oscillations at later stages of maturation. The increase in IP3R1 sensitivity was underpinned by an increase in [Ca2+]ER and receptor phosphorylation(s) but not by changes in IP3R1 cellular distribution, as inhibition of the former factors reduced Ca2+ release, whereas inhibition of the latter had no impact. Therefore, the results suggest that the regulation of [Ca2+]ER and IP3R1 phosphorylation during maturation enhance IP3R1 sensitivity rendering oocytes competent to initiate oscillations at the expected time of fertilization. The temporal discrepancy between the initiation of changes in IP3R1 sensitivity and acquisition of mature oscillatory capacity suggest that other mechanisms that regulate Ca2+ homeostasis also shape the pattern of oscillations in mammalian eggs. J. Cell. Physiol. 227: 705–717, 2012. © 2011 Wiley Periodicals, Inc.
Vitamin A metabolism in benign and malignant melanocytic skin cells: Importance of lecithin/retinol acyltransferase and RPE65
Authors: Amann Philipp M. , Luo Chonglin , Owen Robert W. , Hofmann Claudia , Freudenberger Muriel , Schadendorf Dirk , Eichmüller Stefan B. , Bazhin Alexandr V. 
Published: April 2011

AbstractDisturbance in vitamin A metabolism seems to be an important attribute of cancer cells. Retinoids, particularly retinoic acid, have critical regulatory functions and appear to modulate tumor development and progression. The key step of vitamin A metabolism is the esterification of all‐trans retinol, catalyzed by lecithin/retinol acyltransferase (LRAT). In this work, we show that malignant melanoma cells are able to esterify all‐trans retinol and subsequently isomerize all‐trans retinyl esters (RE) into 11‐cis retinol, whereas their benign counterparts—melanocytes are not able to catalyze these reactions. Besides, melanoma cell lines express lecithin/retinol acyltranseferase both at the mRNA and protein levels. In contrast, melanocytes do not express this enzyme at the protein level, but mRNA of lecithin/retinol acyltransefrase could still be present at mRNA level. RPE65 is expressed in both melanocytic counterparts, and could be involved in the subsequent isomerization of RE produced by lecithin/retinol acyltransefrase to 11‐cis retinol. Cellular retinol‐binding protein 2 does not appear to be involved in the regulation of all‐trans retinol esterification in these cells. Expression of LRAT and RPE65 can be modulated by retinoids. We propose that the post‐transcriptional regulation of lecithin/retinol acyltransefrase could be involved in the differential expression of this enzyme. Besides, activities of LRAT and RPE65 may be important for removal of all‐trans retinal which is the substrate for retinoic acid production in skin cells. Consequently, the decreasing cellular amount of retinoic acid and its precursor molecules could result in a change of gene regulation. J. Cell. Physiol. 227: 718–728, 2012. © 2011 Wiley Periodicals, Inc.