bluuebunny/crossref_metadata_2025_split huggingface dataset:
Benzene increases the ratio of arachidonic acids to docosahexaenoic acids and inhibits the de novo synthesis of ceramide in the rat liver
Authors: Sul Donggeun , Shim Ilsub , Im Hosub , Won NamHee , Kim Hae‐Joon , Lee Eunil 
Published: January 2005

AbstractThe present study investigated the effects of inhalation exposure of benzene at 0, 10, 200 and 600 ppm for 1, 2 and 4 weeks on n‐6 and n‐3 fatty acids and ceramide levels in the rat liver. No signicant difference in the ratio of saturated fatty acid to unsaturated fatty acid was found on increasing benzene exposure levels, but the ratio of saturated fatty acid to unsaturated fatty acid decreased with increasing benzene exposure times, with the exception of the phospholipids of rats exposed to 200 and 600 ppm of benzene. A signicant increase in the ratio of arachidonic acid to docosahexaenoic acid was found in the phospholipids of rats exposed to 200 and 600 ppm of benzene for 4 weeks. In our study, no change in the relative amounts of sphingomyelin in phospholipids, due to benzene exposure at 600 ppm for 4 weeks resulted in the lack of sphingomyelin turnover. However, ceramide levels in the livers of rats exposed to 600 ppm of benzene for 4 weeks were signicantly reduced upon increasing the benzene concentration. This result shows that the de novo synthesis of ceramide was signicantly inhibited at higher levels of benzene and that the ratio of arachidonic acid to docosahexaenoic acid in phospholipids is dose‐dependently related to benzene exposure. Copyright © 2005 John Wiley & Sons, Ltd.
In vitro exposure to quercetin and genistein alters lipid peroxides and prevents the loss of glutathione in human progenitor mononuclear (U937) cells
Authors: Boadi William Y. , Iyere Peter A. , Adunyah Samuel E. 
Published: January 2005

AbstractThe effects of ßavonoids quercetin and genistein were investigated according to their potency to inhibit the oxidation of U937 cells via Fenton's pathway through the analysis of lipid peroxides and glutathione (GSH) levels. Human leukemia (U937) cells from the American Type Culture Collection were maintained at 37 °C for 24 h under 5% CO2 tension in RPMI‐1640 medium containing 10% fetal bovine serum and 50 units ml−1 each of penicillin and streptomycin. Cells were oxidized with iron 50 µM) or copper (50 µM) in H2O2 (0.01 mM) without or with a ßavonoid sample (10 or 20 µM) for the lipid peroxidation studies. The GSH levels were measured (GSH Kit) before and after oxidation as above with different concentrations of ßavonoids (0–40 µM). Lipid peroxide was measured by the thiobarbituric acid assay. Both quercetin and genistein at either the 10 or 20 µM level decreased lipid peroxidation signicantly compared with their respective controls (P < 0.01). Lipid peroxides by Fe compared to the Cu‐treated samples did not differ signicantly from each other. However, the combination of ßavonoids at the doses tested signicantly (P < 0.001) decreased lipid peroxides, the effect being the same for both metal ions. The GSH levels increased signicantly before exposure to the metal ions (for the different doses for the differences between the ßavonoid samples and their respective untreated levels). For quercetin and genistein the increases in GSH above their untreated levels were 4.5, 8.3, 11.7 and 15 and 3.8, 7.9, 12.5 and 14.6 nmol 10−6 cells, respectively, for the 5–40 µM levels tested for each ßavonoid. Following the exposure to the metal ions, GSH levels remained almost the same for the different concentrations for each of the ßavonoids tested but signicantly above all of the controls and same for those of the untreated samples. The results indicate that both ßavonoids inhibited lipid peroxides and the inhibition may be attributed to the prevention of loss of intracellular GSH levels in U937 cells. Copyright © 2005 John Wiley & Sons, Ltd.
Radioprotective and locomotor responses of mice treated with nimodipine alone and in combination with WR‐151327
Authors: Landauer M. R. , Castro C. A. , Benson K. A. , Hogan J. B. , Weiss J. F. 
Published: January 2005

AbstractThe effect of combining a radiation‐protective phosphorothioate with another agent was investigated in an attempt to increase radioprotection and reduce toxicity. The calcium channel blocker nimodipine (NIMO) was administered alone (1 or 10 mg kg−1) or in combination with 200 mg kg−1 of the phosphorothioate radioprotector WR‐151327 (WR) (S‐3‐(3‐methylaminopropylamino)propylphosphorothioic acid). Radioprotection as measured (30‐day survival) of mice treated i.p. 30 min before 60Co irradiation at a dose rate of 1 Gy min−1) was evaluated in CD2F1 male mice. The effects of nimodipine and WR‐151327 on locomotor activity were investigated also in a separate group of non‐irradiated mice. The LD50/30 for the Emulphor vehicle control group was 8.56. For nimodipine alone (1 or 10 mg kg−1) the LD50/30was 8.39 and 10.21 Gy, respectively, yielding dose modification factors (DMFs) of 0.98 and 1.19, respectively. When WR‐151327 was given alone, the <LD50/30 was 12.48 Gy (DMF = 1.46; P < 0.05 from vehicle). WR‐151327 combined with 1 or 10 mg kg−1 nimodipine resulted in an LD50/30 of 12.73 Gy (DMF 1.49, P < 0.05 from vehicle), and when WR‐151327 was combined with 10 mg kg−1 nimodipine the LD50/30 was 14.29 Gy (DMF = 1.67, P < 0.001 from WR‐151327). For either dose of nimodipine, locomotor activity did not differ from vehicle. WR‐151327 and WR‐151327 + 1 mg kg−1 nimodipine resulted in locomotor decrements for up to 4 h post‐administration (P < 0.05 from vehicle), and WR‐151327 + 10 mg kg−1 nimodipine for up to 6 h (P < 0.05 from WR‐151327). Therefore, although there was an additive radioprotective effect when the higher dose of nimodipine was combined with WR‐151327, the locomotor decrement was also enhanced. These results demonstrate that a combination of nimodipine and a phosphorothioate such as WR‐151327 may be useful as a clinical setting where behavioral and physiological side‐effects can be monitored. Published in 2001 by John Wiley & Sons, Ltd.
Uncoupling effect of mercuric chloride on mitochondria isolated from an hepatic cell line
Authors: Königsberg Mina , López‐Díazguerrero Norma Edith , Bucio Leticia , Gutiérrez‐Ruiz María Concepción 
Published: January 2005

AbstractA human fetal hepatic cell line (WRL‐68) was used as a model to study the damage produced by mercury. The Hg(II) uptake by WRL‐68 cells was found to be in a biphasic manner with a rapid initial uptake phase lasting about 5 min, followed by a sustained phase of slower accumulation. Distribution of mercury was studied and mitochondria were found to be the major target for mercury in this cell line (48%), followed by nuclei (38%), cytosol (8%) and microsomes (7%). Mitochondrial morphological damage after mercury treatment was observed by transmission electron microscopy. To determine if the toxic effect of mercury on mitochondrial bioenergetics was direct or indirect, mitochondria were isolated from WRL‐68 cells after 1 h of pre‐incubation with 0.5 µM HgCl2. Oxygen consumption was quantified in two sets of experiments: in the presence of classical mitochondrial respiratory inhibitors; and in the presence of oligomycin. No significant difference was found in respiration with classical inhibitors, indicating that mercury does not affect directly the mitochondrial respiratory chain. However, mitochondria of Hg‐treated cells were not inhibited when oligomycin was added, probably due to an uncoupling effect. This effect was prevented with dithiothreitol (DTT) treatment. A possible explanation for mercury's effect on mitochondria and its relation with oxidative stress is presented. Copyright © 2001 John Wiley & Sons, Ltd.
Quantification of the kinetics and thermodynamics of protein adsorption using atomic force microscopy
Authors: Gettens Robert T. T. , Bai Zhijun , Gilbert Jeremy L. 
Published: January 2005

AbstractBoth in situ and ex situ methods for quantifying area fraction coverage of protein on a surface using atomic force microscopy were developed. The in situ method used a continuous fluid flow system to observe the kinetics of adsorption in real time. The ex situ method required immersing the sample in solution, drying the sample, and imaging in an ambient environment to obtain kinetic and isothermal data. These methods were developed using the plasma protein fibrinogen in a phosphate‐buffered saline solution on grade IV muscovite mica and highly ordered pyrolytic graphite (HOPG) substrates. Kinetic and quasiisothermal data were obtained and a Langmuir model was fit to the data. An adsorption rate constant of 2.2 × 10−4 mL · μg−1s−1 and a desorption rate constant of 8.3 × 10−5 s−1 were found on an HOPG surface. Completely irreversible adsorption was found on the mica surface with an adsorption rate constant of 2.7 × 10−4 mL · μg−1s−1. Additionally, protein conformation and assembly orientation on these surfaces were documented where fibrinogen on HOPG formed a network‐like structure, whereas fibrinogen on mica was more random. Also, nano‐topographical factors (ledges) were seen as sites of preferential adsorption. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 246–257, 2005
Three‐dimensional chemical structures by protein functionalized micron‐sized beads bound to polylysine‐coated silicone surfaces
Authors: Lateef Syed S. , Boateng Samuel , Ahluwalia Neil , Hartman Thomas J. , Russell Brenda , Hanley Luke 
Published: January 2005

AbstractA novel method is described here that allows three‐dimensional (3D) control of both chemistry and morphology by a series of wet chemical steps: the attachment of protein functionalized micron‐sized beads onto a flat silicone surface that has been functionalized with a distinct chemical modification. Bovine serum albumin (BSA), laminin, or polylysine is covalently bound to 6.5‐μm‐diameter spherical beads. A chemical method is then used to bind these beads to a flat silicone surface that is subsequently functionalized with polylysine. This process leads to a nonspecific cell adhesive background on the flat surface (polylysine) with the option of differing chemistry on the third‐dimension due to the protein BSA or laminin on the bead protruding from the surface. The beads do not detach during cyclic stretching in vitro. Neo‐natal rat cardiac fibroblasts are cultured on the beaded surfaces and compared with fibroblasts cultured on nonbeaded, flat polylysine surfaces. Fibroblast plating density, integrin, and physical responses are examined as a function of varying the ligands on the beads. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 373–380, 2005
Potential pitfalls of radiolabel adsorption to ceramic biomaterials
Authors: Parker Tony , Upton Zee , Vellinga Douwe , Wei Mei , Leavesley David 
Published: January 2005

AbstractThe use of radiolabeled precursor molecules for the metabolic analysis of cell functions is commonplace. Tritiated thymidine, in particular, has been used to quantitate cellular proliferation in numerous cells, including osteoblasts, when cultured on various biomaterials. Our aim was to assess cellular protein synthesis and proliferation, on a range of fluoride ion‐substituted hydroxyapatites. Initially, we used a classical metabolic analysis strategy with radiolabeled tracer molecules. Our results suggested that these materials supported enhanced protein synthesis and proliferation of SaOS‐2 human osteoblast‐like cells. However, control samples also revealed enhanced adsorption of the radiolabeled tracer. We have shown that this arises because partially fluoride ion‐substituted hydroxyapatite exhibits enhanced adsorptive characteristics of radiolabeled leucine and thymidine over tissue culture plastic, hydroxyapatite, and fluoroapatite. Moreover, manual cell count data obtained through SEM analysis showed no significant difference in cell proliferation between any of the materials, further indicating that our initial results were artifacts. These results highlight the use and reporting of appropriate cell‐free controls are critical in bioassays examining functional responses of cells to biomaterials, and if absent, may confound accurate data interpretation. Our findings have general implications for investigations of cell function on other novel ceramic biomaterials. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 363–372, 2005
Effect of poly‐L‐lysine coating on macrophage activation by alginate‐based microcapsules: Assessment using a new in vitro method
Authors: Juste Sandy , Lessard Mélanie , Henley Nathalie , Ménard Martin , Hallé Jean‐Pierre 
Published: January 2005

AbstractThe characteristics of the microcapsule surface, which interacts directly with the host macrophages, may have a role in the biocompatibility of alginate‐poly‐L‐lysine (PLL)‐alginate (APA) microcapsule. The objectives of the study were: 1) to develop and validate a simple, rapid, and sensitive in vitro method for assessing microcapsule biocompatibility, based on microcapsule coincubation with macrophages and measurement, by reverse transcriptase‐polymerase chain reaction, of cytokine mRNA expression, and 2) to evaluate the effect of alginate purification and PLL coating on macrophage activation. The mRNA expression of tumor necrosis factor‐α and interleukin‐1β was significantly higher when macrophages were coincubated with beads made with nonpurified compared with purified alginate (p < 0.01, p < 0.05, respectively) and negative control (p < 0.001) or with APA microcapsules compared with non‐PLL‐coated alginate beads and negative control (p < 0.001). The mRNA expression of interleukin‐6 differed significantly only when APA microcapsules were compared with a negative control (p < 0.05). These results confirm that alginate purification improves microcapsule biocompatibility, and suggest that PLL is not completely covered and/or neutralized by the second alginate incubation and thus has a role in the host macrophage activation. The assay is sensitive to both alginate contaminants and microcapsule surface characteristics and may be a useful tool for the development of biocompatible microcapsules. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 389–398, 2005
Insulin‐like growth factor‐1 increases endothelin receptor A levels and action in cultured rat aortic smooth muscle cells
Authors: Kwok Ching Fai , Juan Chi‐Chang , Shih Kuang‐Chung , Hwu Chii‐Min , Jap Tjin‐Shing , Ho Low‐Tone 
Published: January 2005

AbstractInsulin is known to cause an increase in endothelin‐1 (ET‐1) receptors in vascular smooth muscle cells (SMCs), but the effect of insulin‐like growth factor 1 (IGF‐1) on ET‐1 receptor expression is not known. We therefore carried out the present study to determine the effect of IGF‐1 on the binding of ET‐1 to, and ET type A receptor (ETAR) expression and ET‐1‐induced 3H‐thymidine incorporation in, vascular SMCs. In serum‐free medium, IGF‐1 treatment increased the binding of 125I‐ET‐1 to SMC cell surface ET receptors from a specific binding of 20.1% ± 3.1% per mg of protein in control cells to 45.1% ± 8.6% per mg of protein in cells treated with IGF‐1 (10 nM). The effect of IGF‐1 was dose‐related, with a significant effect (1.4‐fold) being seen at 1 nM. The minimal time for IGF‐1 treatment to be effective was 30 min and the maximal effect was reached at 6 h. Immunoblotting analysis showed that ETAR expression in IGF‐1‐treated cells was increased by 1.7‐fold compared to controls. Levels of ETAR mRNA measured by the RT‐PCR method and Northern blotting were also increased by 2‐fold in IGF‐1‐treated SMCs. These effects of IGF‐1 were abolished by cycloheximide or genistein. Finally, ET‐1‐stimulated thymidine uptake and cell proliferation were enhanced by IGF‐1 treatment, with a maximal increase of 3.2‐fold compared to controls. In conclusion, in vascular SMCs, IGF‐1 increases the expression of the ET‐1 receptor in a dose‐ and time‐related manner. This effect is associated with increased thymidine uptake and involves tyrosine kinase activation and new protein synthesis. These findings support the role of IGF‐1 in the development of atherosclerotic, hypertensive, and diabetic vascular complications. © 2004 Wiley‐Liss, Inc.
Construction and characterization of multiple human colon cancer cell lines for inducibly regulated gene expression
Authors: Welman Arkadiusz , Cawthorne Christopher , Barraclough Jane , Smith Nigel , Griffiths Gareth J. , Cowen Rachel L. , Williams Judith C. , Stratford Ian J. , Dive Caroline 
Published: January 2005

AbstractValidation of targets for cancer drug discovery requires robust experimental models. Systems based on inducible gene expression are well suited to this purpose but are difficult to establish in several epithelial cell types. Using the recently discovered transcriptional transactivator (rtTA2S‐M2), we developed a strategy for fast and efficient generation of Tet On cells. Multiple clones of HCT116, SW480, and HT29 human colon cancer cells for doxycycline‐regulated gene expression were constructed that constitutively express green fluorescent protein (GFP) for selection/maintenance purposes. The cell lines displayed good fold inducibility (49–124× HCT116; 178–621× SW480; 261–787× HT29) and minimal leakiness after transient transfection with a luciferase reporter or with vectors driving inducible expression of red fluorescent protein (dsRed2), constitutively active c‐Src or dominant negative K‐Ras4B. The clones preserved their transformed phenotype as demonstrated by comparing their properties to respective wild type cells, in terms of growth in vitro and in vivo (as tumor xenografts), cell cycle traverse, and sensitivity to drugs used in chemotherapy. These engineered cell lines enabled tightly controlled inducible gene expression both in vitro and in vivo, and proved well suited for construction of double‐stable cell lines inducibly expressing a protein of interest. As such they represent a useful research tool for example, to dissect oncogene function(s) in colon cancer. Supplementary material for this article be found at http://www.mrw.interscience.wiley.com/suppmat/0730‐2312/suppmat/94/suppmat_welman.doc. © 2005 Wiley‐Liss, Inc.
Effects of cell cycle status on early events in retroviral replication
Authors: Katz Richard A. , Greger James G. , Skalka Anna Marie 
Published: January 2005

AbstractThe study of retroviruses over the last century has revealed a wide variety of disease‐producing mechanisms, as well as apparently harmless interactions with animal hosts. Despite their potential pathogenic properties, the intrinsic features of retroviruses have been harnessed to create gene transfer vectors that may be useful for the treatment of disease. Retroviruses, as all viruses, have evolved to infect specific cells within the host, and such specificities are relevant to both pathogenesis and retrovirus‐based vector design. The majority of cells of an animal host are not progressing rapidly through the cell cycle, and such a cellular environment appears to be suboptimal for replication of all retroviruses. Retrovirus‐based vectors can therefore be restricted in many important target cells, such as post‐mitotic differentiated cells or stem cells that may divide only infrequently. Despite intense interest, our understanding of how cell cycle status influences retroviral infection is still quite limited. In this review, we focus on the importance of the cell cycle as it relates to the early steps in retroviral replication. Retroviruses have been categorized based on their abilities to complete these early steps in non‐cycling cells. However, all retroviruses are subject to a variety of cell cycle restrictions. Here, we discuss such restrictions, and how they may block retroviral replication, be tolerated, or overcome. J. Cell. Biochem. 94: 880–889, 2005. © 2005 Wiley‐Liss, Inc.
Cellular transformation of NIH3T3 fibroblasts by CIZ/NMP4 fusions
Authors: Corveleyn Anniek , Janssen Hilde , Martini Alessandra , Somers Riet , Cools Jan , Marynen Peter 
Published: January 2005

AbstractMolecular cloning of the translocations t(12;22)(p13;q12) and t(12;17)(p13;q11) in acute leukaemia showed that either EWSR1 or its homologue TAF15 are fused to the transcription factor CIZ. EWSR1 and TAF15 belong to the TET family (TLS/FUS, EWSR1 and TAF15) of proteins. TET fusions have been identified in both solid tumours and acute myeloid leukaemia. The novel 12p translocations directly implicated TET fusions in acute lymphoblastic leukaemia as well, and demonstrated the involvement of CIZ in haematopoietic malignancies. In addition, a new fusion E2A‐CIZ was recently cloned as a result of a t(12;19)(p13;p13) in a patient with acute lymphoblastic leukaemia. NIH3T3 cells stably expressing TET‐CIZ fusions display a transformed phenotype in a focus formation assay. We show here that E2A‐CIZ also transforms 3T3 fibroblasts, suggesting that the addition of a transactivation domain to the CIZ protein is involved in this phenotype. An artificial VP16‐CIZ construct reveals similar transforming properties, supporting this. We have then analysed the domains within TAF15‐CIZ that are necessary for 3T3 fibroblast transformation. Deletion of the zinc fingers of CIZ resulted in loss of both DNA‐binding and transforming properties of TAF15‐CIZ, whereas deletion of the other functional domains of CIZ had no effect. Fusion of a transactivation domain to CIZ is suggestive for a transactivating function in transformation. Luciferase experiments indeed showed that E2A‐CIZ as well as VP16‐CIZ transactivates the MMP7 promoter. Taken together, our results reported here suggest that transformation of 3T3 fibroblasts by CIZ fusions is dependent on DNA‐binding and might involve transactivation of CIZ target genes. © 2004 Wiley‐Liss, Inc.
Dexamethasone upregulates the expression of the nuclear cofactor p300 and its interaction with C/EBPβ in cultured myotubes
Authors: Yang Hongmei , Menconi Michael J. , Wei Wei , Petkova Victoria , Hasselgren Per‐Olof 
Published: January 2005

AbstractMuscle wasting during sepsis and other catabolic conditions is, at least in part, mediated by glucocorticoids and is associated with upregulated transcription of multiple genes in the ubiquitin‐proteasome proteolytic pathway. In addition to transcription factors, nuclear cofactors, including p300, regulate gene transcription. We tested the hypothesis that glucocorticoids upregulate the expression of p300 in muscle cells. Treatment of cultured L6 myotubes, a rat skeletal muscle cell line, with dexamethasone resulted in a dose‐ and time‐dependent increase in p300 protein and mRNA levels. Surprisingly, the effect of dexamethasone on p300 levels was not inhibited by the glucocorticoid receptor (GR) antagonist RU38486 and RU38486 exerted an agonist effect on p300, increasing its expression. Co‐immunoprecipitation showed that treatment of the myotubes with dexamethasone resulted in protein–protein interaction between p300 and C/EBPβ, but not C/EBPδ. The present results suggest that glucocorticoids upregulate the expression of p300 and its interaction with C/EBPβ in skeletal muscle. Increased expression and activity of p300 may be involved in the regulation of gene transcription in glucocorticoid‐dependent muscle wasting. J. Cell. Biochem. 94: 1058–1067, 2005. © 2005 Wiley‐Liss, Inc.