bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zinc partitions insulin‐like growth factors (IGFs) from soluble IGF binding protein (IGFBP)‐5 to the cell surface receptors of BC3H‐1 muscle cells
Authors: McCusker Robert H. , Novakofski Jan 
Published: October 2003

AbstractZinc (Zn2+) is a multifunctional micronutrient. The list of functions for this micronutrient expanded with the recent discovery that Zn2+ retains insulin‐like growth factors binding proteins (IGFBPs) on the surface of cultured cells, lowers the affinity of cell‐associated IGFBPs, and increases the affinity of the cell surface insulin‐like growth factor (IGF)‐type 1 receptor (IGF‐1R). However, currently there is no information concerning the effect of Zn2+ on soluble IGFBPs. In the current study, the soluble IGFBP‐5 secreted by BC3H‐1 cells is shown to bind approximately 50% more [125I]‐IGF‐II than [125I]‐IGF‐I at pH 7.4. Zn2+ is shown to depress the binding of both IGF‐I and IGF‐II to soluble secreted IGFBP‐5; [125I]‐IGF‐I binding is affected more so than [125I]‐IGF‐II binding. Zn2+ acts by lowering the affinity (Ka) of IGFBP‐5 for the IGFs. Scatchard plots are non‐linear indicating the presence of high and low affinity binding sites; Zn2+ affects only binding to the high affinity site. In contrast, Zn2+ increases the affinity by which either [125I]‐IGF‐I or [125I]‐R3‐IGF‐I binds to the IGF‐1R, but depresses [125I]‐IGF‐II binding to the IGF‐type 2 receptor (IGF‐2R) on BC3H‐1 cells. By depressing the association of the IGFs with soluble IGFBPs, Zn2+ is shown to repartition either [125I]‐IGF‐I or [125I]‐IGF‐II from soluble IGFBP‐5 onto cell surface IGF receptors. Zn2+ was active at physiological doses depressing IGF binding to IGFBP‐5 and the IGF‐2R at 15–20 μM. Hence, a novel mechanism is further characterized by which the trace micronutrient Zn2+ could regulate IGF activity. J. Cell. Physiol. 197: 388–399, 2003© 2003 Wiley‐Liss, Inc.
Grb10 adapter protein as regulator of insulin‐like growth factor receptor signaling
Authors: Morrione Andrea 
Published: October 2003

AbstractGrb10 is a member of a superfamily of adapter proteins that includes Grb10, 7, 14, and a protein of Caenorhabditis elegans called Mig10. Grb10 proteins are binding partners for several trans‐membrane tyrosine‐kinase receptors, including the insulin‐like growth factor receptor (IGF‐IR) and the insulin receptor (IR). Many recent reports have suggested a very important role of Grb10 in regulating IGF‐IR signaling. In this review, we will focus on the role of Grb10 in IGF‐I‐induced mitogenesis and we will discuss the recent findings that show the involvement of Grb10 in the regulation of ligand‐induced ubiquitination, internalization, and stability of the IGF‐IR. J. Cell. Physiol. 197: 307–311, 2003© 2003 Wiley‐Liss, Inc.
How to overcome (and exploit) tumor hypoxia for targeted gene therapy
Authors: Greco Olga , Marples Brian , Joiner Michael C. , Scott Simon D. 
Published: October 2003

AbstractTumor hypoxia has long been recognized as a critical issue in oncology. Resistance of hypoxic areas has been shown to affect treatment outcome after radiation, chemotherapy, and surgery in a number of tumor sites. Two main strategies to overcome tumor hypoxia are to increase the delivery of oxygen (or oxygen‐mimetic drugs), and exploiting this unique environmental condition of solid tumors for targeted therapy. The first strategy includes hyperbaric oxygen breathing, the administration of carbogen and nicotinamide, and the delivery of chemical radiosensitizers. In contrast, bioreductive drugs and hypoxia‐targeted suicide gene therapy aim at activating cytotoxic agents at the tumor site, while sparing normal tissue from damage. The cellular machinery responds to hypoxia by activating the expression of genes involved in angiogenesis, anaerobic metabolism, vascular permeability, and inflammation. In most cases, transcription is initiated by the binding of the transcription factor hypoxia‐inducible factor (HIF) to hypoxia responsive elements (HREs). Hypoxia‐targeting for gene therapy has been achieved by utilizing promoters containing HREs, to induce selective and efficient transgene activation at the tumor site. Hypoxia‐targeted delivery and prodrug activation may add additional levels of selectivity to the treatment. In this article, the latest developments of cancer gene therapy of the hypoxic environment are discussed, with particular attention to combined protocols with ionizing radiation. Ultimately, it is proposed that by adopting specific transgene activation and molecular amplification systems, resistant hypoxic tumor tissues may be effectively targeted with gene therapy.
J. Cell. Physiol. 197: 312–325, 2003© 2003 Wiley‐Liss, Inc.
Transforming growth factor‐β induces expression of vascular endothelial growth factor in human retinal pigment epithelial cells: Involvement of mitogen‐activated protein kinases
Authors: Nagineni Chandrasekharam N. , Samuel William , Nagineni Sahrudaya , Pardhasaradhi Komanduri , Wiggert Barbara , Detrick Barbara , Hooks John J. 
Published: October 2003

AbstractVascular endothelial growth factor (VEGF) is a major agent in choroidal and retinal neovascularization, events associated with age‐related macular degeneration (AMD) and diabetic retinopathy. Retinal pigment epithelium (RPE), strategically located between retina and choroid, plays a critical role in retinal disorders. We have examined the effects of various growth factors on the expression and secretion of VEGF by human retinal pigment epithelial cell cultures (HRPE). RT‐PCR analyses revealed the presence of three isoforms of mRNA corresponding to VEGF 121, 165, and 189 that were up regulated by TGF‐β1. TGF‐β1, β2, and β3 were the potent inducers of VEGF secretion by HRPE cells whereas bFGF, PDGF, TGF‐α, and GM‐CSF had no effects. TGF‐β receptor type II antibody significantly reversed induction of VEGF secretion by TGF‐β. In contrast activin, inhibin and BMP, members of TGF‐β super family, had no effects on VEGF expression in HRPE. VEGF mRNA levels and protein secretion induced by TGF‐β were significantly inhibited by SB203580 and U0126, inhibitors of MAP kinases, but not by staurosporine and PDTC, protein kinase C and NF‐κB pathway inhibitors, respectively. TGF‐β also induced VEGF expression by fibroblasts derived from human choroid of eye. TGF‐β induction of VEGF secretion by RPE and choroid cells may play a significant role in choroidal neovascularization (CNV) in AMD. Since the secretion of VEGF by HRPE is regulated by MAP kinase pathways, MAP kinase inhibitors may have potential use as therapeutic agents for CNV in AMD. Published 2003 Wiley‐Liss, Inc. J. Cell. Physiol. 197: 453–462, 2003© 2003 Wiley‐Liss, Inc.
Defective P2Y purinergic receptor function: A possible novel mechanism for impaired glucose transport
Authors: Solini Anna , Chiozzi Paola , Morelli Anna , Passaro Angela , Fellin Renato , Virgilio Francesco Di 
Published: October 2003

AbstractExtracellular ATP is an ubiquitous mediator that regulates several cellular functions via specific P2 plasma membrane receptors (P2Rs), for which a role in modulating intracellular glucose metabolism has been recently suggested. We have investigated glucose uptake in response to P2Rs stimulation in fibroblasts from type 2 diabetic (T2D) patients and control subjects. P2Rs expression was evaluated by RT‐PCR; intracellular calcium release by fluorometry; glucose transporter (GLUT1) translocation by immunoblotting and chemiluminescence; glucose uptake was measured with 2‐deoxy‐D‐[1‐3H]glucose (2‐DOG) and ATP by luminometry. Cells from T2D patients, in contrast to those from healthy controls, showed no increase in glucose uptake after ATP stimulation; extracellular ATP caused, however, a similar GLUT1 recruitment to the plasma membrane in both groups. P2Rs expression did not differ between fibroblasts from diabetic and healthy subjects, but while plasma membrane depolarization, a P2X‐mediated response was similar in both groups, no evident intracellular calcium increase was detectable in the cells from the former group. The calcium response in fibroblasts from diabetics was restored by co‐incubation with apyrase or hexokinase, suggesting that P2YRs in those cells were normally expressed but chronically desensitised. In support to this finding, fibroblasts from T2D subjects secreted a two‐fold larger amount of ATP compared to controls. Pre‐treatment with apyrase or hexokinase also restored ATP stimulated glucose uptake in fibroblasts from diabetic subjects. These results suggest that extracellular ATP plays a role in the modulation of glucose transport via GLUT1, and that the P2Y‐dependent GLUT1 activation is deficient in fibroblasts from T2D individuals. Our observations may point to additional therapeutic targets for improving glucose utilization in diabetes. J. Cell. Physiol. 197: 435–444, 2003© 2003 Wiley‐Liss, Inc.
Stable overexpression of specific segments of the P2P‐R protein in human MCF‐7 cells promotes camptothecin‐induced apoptosis
Authors: Gao S. , Scott R.E. 
Published: October 2003

AbstractThe stable overexpression of near full‐length P2P‐R protein in human Saos 2 cells restricts cell cycle progression by inducing mitotic arrest at prometaphase and mitotic apoptosis (Gao and Scott, 2002, J Cell Physiol 193: 199–207). Those effects of P2P‐R were observed in Saos‐2 cells that lack p53 and employ a caspase‐3‐dependent apoptotic signaling pathway. The current studies were performed to evaluate if overexpression of specific segments of the P2P‐R protein promote apoptosis in human MCF‐7 cells that contain p53 and employ a different apoptotic signaling pathway. Since segments of P2P‐R were found not to induce apoptosis independently, the ability of three different P2P‐R segments to promote camptothecin‐induced apoptosis was evaluated following their stable transfection and expression in MCF‐7 cells. Relative to full‐length P2P‐R (1–1560 aa), the three P2P‐R segments used in these studies included: P2P‐R‐2 (761–1560 aa), P2P‐R‐3 (1156–1560 aa), and P2P‐R‐4 (1314–1560 aa). The results document that overexpression of P2P‐R‐2 and P2P‐R‐3 promotes camptothecin‐induced apoptosis by three to fivefold when assayed by flow cytometric analysis of apoptotic sub 2n cell populations or by TUNEL assays. In contrast, P2P‐R‐4 had no effect on apoptosis. These results suggest that the ability of P2P‐R to promote camptothecin‐induced apoptosis in MCF‐7 cells involves a specific region (1156–1314 aa) that exists within P2P‐R. The data presented also show that the p53 binding domain of P2P‐R overlaps with the apoptosis‐associated region and previous studies documented that this region of P2P‐R also binds single‐strand nucleotides (Witte and Scott, 1997, Proc Natl Acad Sci USA 94: 1212–1217). Therefore, P2P‐R‐promoted apoptosis induced by camptothecin may be influenced by such interactions. J. Cell. Physiol. 197: 445–452, 2003© 2003 Wiley‐Liss, Inc.
A rapid method for assessment of plant residue quality
Authors: Praveen‐Kumar  , Tarafdar Jagadish C. , Panwar Jitendra , Kathju Shyam 
Published: October 2003

AbstractA simple, reproducible and new method (modified dehydrogenase activity measurement after 72 h; DHA 72) was developed to assess plant residue quality for decomposition. The method resulted in similar assessments of residue quality than measurements of the C:N ratio, lignin:N ratio, and lignin and polyphenol concentration (PRQI). Among 25 plant residues tested, there was a large variation of DHA 72 as found in other well‐established methods. Based on cluster analysis, plant residues were grouped in four different classes; highly decomposable, moderately decomposable, slowly decomposable, and least decomposable. It is concluded that DHA 72 can very well be used to screen plant residues for residue quality judgment. The proposed method is very simple and easy to handle.
Uptake of residual phosphate and freshly applied diammonium phosphate byLolium perenneandTrifolium repens
Authors: Gallet Anne , Flisch René , Ryser Jean‐Pierre , Nösberger Joseph , Frossard Emmanuel , Sinaj Sokrat 
Published: October 2003

AbstractResidual fertilizer phosphorus (residual P) may significantly contribute to crop P nutrition. To test this hypothesis, a pot experiment was conducted with ryegrass(Lolium perenne)and clover(Trifolium repens)grown separately on three different soils which either had not received P fertilizer for at least nine years (0F) or had received P fertilizer equivalent to crop P off‐take (F). Soils in the pot experiment were given either none (0F, F) or a single rate of 15 mg P (kg soil)–1as diammonium phosphate (0F+DAP, F+DAP). In the treatments0F+DAPandF+DAPDAP had been labeled with33PO4while in the treatments0FandFthe pool of available soil P had been labeled with carrier‐free33PO4. This allowed estimating the quantities of P in plant dry matter that derived from native soil P, residual fertilizer P or fresh fertilizer P. Fourteen to 62 % of the P in the above ground biomass of white clover or perennial ryegrass were derived from residual P whereas 7 to 28 % were derived from freshly applied DAP. The proportion of P derived from residual P was correlated to the total amount of P fertilizer added to the soils, while the proportion of P derived from DAP was correlated to the concentration of P in the soil solution of the0FandFsoils.
Effect of phosphate fertilization on crop yield and soil phosphorus status
Authors: Gallet Anne , Flisch René , Ryser Jean‐Pierre , Frossard Emmanuel , Sinaj Sokrat 
Published: October 2003

AbstractTo evaluate the effect of three phosphorus (P) fertilization regimes (no P, P input equivalent to P off‐take by crops, P input higher than P off‐take) on crop yield, P uptake, and soil P availability, seven field experiments (six in crop rotations, one under permanent grassland) were conducted in Switzerland during nine years (six trials) or 27 years (one trial). Soil total P (Pt), inorganic P (Pi), organic P (Po), and the amount of isotopically exchangeable soil P were measured in the 0–20 cm and 30–50 cm layers of the arable soils and in the 0–10 cm layer of the permanent grassland soil. Omitting P fertilization resulted in significant yield decreases only in one field crop trial as the amount of P isotopically exchangeable within one minute (E1min) reached values lower than 5 mg P (kg soil)–1. In the absence of P fertilization Pi decreased on average from 470 to 410 mg P (kg soil)–1 in the upper horizon of 6 sites while Po decreased only at two sites (from 510 to 466 mg P (kg soil)–1 on average). In all the treatments of the trials started in 1989 the E1min values of the upper horizon decreased on average from 15.6 to 7.4 mg P (kg soil)–1 between 1989 and 1998. These decreases were also observed when P inputs were higher than crops needs, showing that in these soils the highest P inputs were not sufficient to maintain the high initial available P levels. Finally for the six arable trials the values of the isotopic exchange kinetics parameters (R/r1, n, CP) and P exchangeable within 1 minute (E1min) at the end of the experiment could be estimated from the values measured at the beginning of trial and the cumulated P balance.
Effects of consecutive applications of gypsum in equal, increasing, and decreasing quantities on soil hydraulic conductivity of a saline‐sodic soil
Authors: Sahin Ustun , Oztas Taskin , Anapali Omer 
Published: October 2003

AbstractThe objective of this study was to determine the effects of consecutive application of gypsum dissolved in leaching water on hydraulic conductivity of a saline‐sodic soil. Drainage type plastic columns with a 10 cm diameter were used in this laboratory experiment. Soil depth within columns was 30 cm with an average bulk density of 1.38 g cm–3. Leaching water was applied in six equal portions. Total gypsum was applied at 1, 3, and 5 portions after dissolving in leaching water. In dissolution, equal (1.273 + 1.273 + 1.273 Mg ha–1), increasing (0.637 + 1.273 + 1.910 Mg ha–1) and decreasing (1.910 + 1.273 + 0.637 Mg ha–1) quantities of gypsum were used. Results were compared with the control treatment, in which total amount of gypsum were mixed with surface layer of soil column before leaching. Hydraulic conductivity of soil increased in all treatments. The maximum hydraulic conductivity value was obtained at consecutive application of gypsum at decreasing quantities.
Chemical changes in the rhizosphere of metal hyperaccumulator and excluder Thlaspi species
Authors: Puschenreiter Markus , Wieczorek Simone , Horak Othmar , Wenzel Walter W. 
Published: October 2003

AbstractRhizosphere processes involved in hyperaccumulation and exclusion of metals are still largely unknown. Therefore, we conducted a rhizobag experiment on contaminated and non‐contaminated soils to investigate the chemical changes in the rhizosphere of the hyperaccumulators Thlaspi goesingense and T. caerulescens, and the metal‐excluder T. arvense. Root growth was restricted to the rhizobags separated by a nylon membrane (7 μm \x 25 μm mesh size) from surrounding bulk soil. Depletion of labile Zn in rhizosphere could not explain the amount of metals accumulated in T. caerulescens, whereas the difference in EDTA‐extractable Zn even exceeded total plant uptake. Substantially increased DOC in T. arvense rhizosphere indicates alleviation of phytotoxicity by formation of metal‐organic complexes. Hyperaccumulation and depletion of labile Zn in the rhizosphere was observed for T. goesingense grown on contaminated soil. On non‐contaminated soil, Zn was accumulated but labile Zn in rhizosphere was not changed. Nickel present in background concentrations in both soils was accumulated by T. goesingense only when grown on non‐contaminated soil. In contrast, labile Ni in the rhizosphere was increased in both soils, suggesting a general tendency of Ni mobilization by T. goesingense.
Relationship between heme vinyl conformation and the protein matrix in peroxidases
Authors: Marzocchi Mario P. , Smulevich Giulietta 
Published: October 2003

AbstractA direct relationship between the ν and Cb atoms of the vinyl groups and the surrounding atoms, the origin of the different vinyl orientations is ascribed to a variety of interactions, namely van der Waals contacts, weak π–π electron interactions and C—H···O hydrogen bonds. The vinyl group orientations appear to depend on the concerted orientations of the distal helix B and proximal helix F axes as controlled by the H‐bonds between the distal Arg, a heme propionyl group and a residue on the extended strand adjacent to proximal helix F. Finally, a possible mechanism explaining the alkaline configuration changes of cytochrome c peroxidase and the reorientation of a vinyl group upon fluoride complexation is given. Copyright © 2003 John Wiley & Sons, Ltd.
Applicability of laser‐induced Raman microscopy for in situ monitoring of imine formation in a glass microfluidic chip
Authors: Lee Moonkwon , Lee Jong‐Phil , Rhee Hakjune , Choo Jaebum , Gyu Chai Young , Kyu Lee Eun 
Published: October 2003

AbstractLaser‐induced Raman microscopy has been used to illustrate its applicability for the in situ monitoring of imine formation reaction in a glass microfluidic chip. In order to monitor the diffusion process in a micro channel, the Raman spectra were measured at various points along the channel with a constant flow rate of 2.7 µl min−1. Time‐dependent Raman spectra were also measured without flow in order to monitor the variation of Raman peaks to a complete conversion. The disappearance of the CO stretching peak at 1700 cm−1 of the reactant, benzaldehyde, and the appearance of the Raman peak for the product, an imine, at 1628 cm−1 were successfully monitored. In addition, the intensity increases of three phenyl stretching modes in the 1550–1630 cm−1 region were also observed. The increase in Raman intensity for this vibrational mode is caused by an effective π‐electron conjugation between two phenyl rings through the —CN—bridging group of the product. Laser‐induced Raman microscopy enables us to monitor in situ product formation and to obtain detailed structural information in a glass microfluidic chip. Copyright © 2003 John Wiley & Sons, Ltd.
Raman spectroscopic study of spodumene (LiAlSi2O6) through the pressure‐induced phase change from C2/c to P21/c
Authors: Pommier C. J. S. , Denton M. B. , Downs R. T. 
Published: October 2003

AbstractHigh‐pressure Raman spectroscopy was used to follow the effects of a phase transition on the Raman spectrum of a natural specimen of the pyroxene spodumene, from its low‐pressure (C2/c) to its high‐pressure (P21/c) phases. The transition occurred at 3.2 GPa and was accompanied by an increase from 15 to 23 observed peaks, owing to a decrease in symmetry. Comparisons were made with other pyroxenes with the same space groups. The change in Raman shift with pressure of all peaks observed is reported. An additional change in the spectrum is observed between 7.7 and 8.9 GPa, possibly due to the formation of an additional bond between Li and O3 or some other transition that retained the mineral's P21/c space group. Splitting of the peak appearing at ∼700 cm−1, used to characterize the P21/c phase in other studies, was not observed. Copyright © 2003 John Wiley & Sons, Ltd.
Low‐temperature Raman spectra of Sr0.66Ba0.34Nb2O6 single‐crystal fibers
Authors: Faria J. L. B. , Freire P. T. C. , Ayala A. P. , Melo F. E. A. , Filho J. Mendes , Paschoal C. W. A. , Santos I. A. , Eiras J. A. 
Published: October 2003

AbstractA possible structural change in Sr0.66Ba0.34Nb2O6 single‐crystal fibers when the temperature decreases from 295 to 10 K was investigated by dielectric constant measurements and Raman spectroscopy. An anomaly observed in the dielectric constant and the loss factor is associated with the variation in the intensity and wavenumber of certain Raman modes. We observe that the relative intensity of low wavenumber modes has a singular behavior for the y(xz)ȳ scattering geometry. A high‐wavenumber band disappears when the temperature is lowered to 10 K for the y(xz)ȳ geometry and shifts to higher wavenumber for the y(zz)ȳ geometry. These observations can be interpreted as evidence of a structural phase transition undergone by Sr0.66Ba0.34Nb2O6 single‐crystal fibers at temperatures below 100 K. Copyright © 2003 John Wiley & Sons, Ltd.
Microprocesses of metal dusting on iron‐nickel alloys and their dependence on the alloy composition
Authors: Pippel E. , Woltersdorf J. , Grabke H. J. 
Published: October 2003

AbstractMetal dusting of iron proceeds via the formation and disintegration of the metastable carbide Fe3C, and the resulting fine Fe particles in the coke further catalyse carbon deposition. By contrast, nickel disintegrates directly, and larger grains are released. As revealed by TEM and AEM techniques, in both cases the disintegration proceeds by inward growth of thin graphite filaments, the atomic basal planes of which being oriented perpendicular to the surface thus effecting a high reactivity at the growth front.Consequently, successive alloying of iron with nickel should lead to a change over from one disintegration mechanism to the other, and, in fact, we could evidence that the carbide formation takes place only up to a nickel content of about 5 wt.%. Already at a Ni concentration of 10 wt.% a direct disintegration of the metal proceeds, as it is typical for pure nickel. Furthermore, in all investigated Ni‐Fe alloys a surface‐near enrichment of Ni was observed which indicates a selective corrosion of Fe, decreasing with increasing Ni content of the basic alloy.