bluuebunny/crossref_metadata_2025_split huggingface dataset:
Astroglia growth retardation and increased microglia proliferation by lithium and ornithine decarboxylase inhibitor in rat cerebellar cultures: Cytotoxicity by combined lithium and polyamine inhibition
Authors: Gilad Gad M. , Gilad Varda H. 
Published: December 2006

AbstractLithium, the most prevalent treatment for manic‐depressive illness, might have a neuroprotective effect after brain injury. In culture, lithium can exert neurotoxic effects associated with reduction in polyamine synthesis but neuroprotective effects as cultured neurons mature. Cumulative evidence suggests that lithium may exert some of its effects on neurons indirectly, by initially acting on glial cells. We used rat cerebellar cultures to ascertain the effects of lithium on ornithine decarboxylase (ODC) activity, the enzyme catalyzing the first step in polyamine synthesis, and to compare effects of lithium with those of the ODC inhibitor α‐difluoromethylornithine (DFMO) on neuron survival and glial growth. Switching cultures from high (25 mM) to low (5 mM) KCl concentrations served as the traumatic neuronal insult. The results indicate the following. 1) Whereas high depolarizing KCl concentration enhances neuron survival, it inhibits astroglial growth. 2) Lithium (LiCl; 1–5 mM) enhances neuronal survival but inhibits astroglial growth. 3) Lithium treatment leads to reduced ODC activity. 4) DFMO enhances neuron survival but inhibits astroglial growth. 5) Lithium and DFMO lead to transformation of astroglia from epithelioid (flat) to process‐bearing morphology and to increased numbers of microglia. 6) Combined lithium plus DFMO treatment is cytolethal to both neurons and glia in culture. In conclusion, lithium treatment results in growth retardation and altered cell morphology of cultured astroglia and increased microglia proliferation, and these effects may be associated with inhibition of polyamine synthesis. This implies that direct effects on astrocytes and microglia may contribute to the effects of lithium on neurons. © 2006 Wiley‐Liss, Inc.
Glutathione elevation by γ‐glutamyl cysteine ethyl ester as a potential therapeutic strategy for preventing oxidative stress in brain mediated by in vivo administration of adriamycin: Implication for chemobrain
Authors: Joshi Gururaj , Hardas Sarita , Sultana Rukhsana , St. Clair Daret K. , Vore Mary , Butterfield D. Allan 
Published: December 2006

AbstractOxidative stress in heart and brain by the cancer chemotherapeutic drug adriamycin (ADR), used for treating solid tumors, is well established. Long‐term treatment with ADR in breast cancer patients has led to symptoms of cardiomyopathy. Less well recognized, but increasingly well documented, is cognitive dysfunction. After chemotherapy, free radical‐mediated oxidative stress has been reported in both heart and brain. We recently showed a significant increase in protein oxidation and lipid peroxidation in brain isolated from mice injected intraperitonially (i.p) with ADR. Systemic administration of ADR also induces tumor necrosis factor‐α (TNF‐α), which leads to production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in brain. Circulating TNF also causes mitochondrial dysfunction, leading to apoptotic pathways in brain. Inducible nitric oxide synthase also plays a role in ADR‐induced TNF‐mediated neurotoxicity. In addition, we previously showed a significant decrease in glutathione (GSH) levels in brain isolated from ADR injected mice, along with increased expression of multidrug‐resistant protein‐1 (MRP‐1), glutathione‐S‐transferase (GST), glutathione peroxidase (GPx), and glutathione reductase (GR). There was a significant decrease in activity of brain GST. The present study was designed to test the hypothesis that, by elevating brain levels of GSH, the brain would be protected against oxidative stress in ADR‐injected mice. γ‐Glutamyl cysteine ethyl ester (GCEE), a precursor of glutathione, injected i.p. (150 mg/ kg body weight) 4 hr prior ADR injection (20 mg/kg body weight) led to significantly decreased protein oxidation and lipid peroxidation in subsequently isolated mice brain compared with brain isolated from ADR‐injected mice without GCEE. The GSH levels were restored to the level of brain isolated from saline‐injected mice. Furthermore, the enzyme activity of GST was increased in brain isolated from ADR‐injected mice previously injected with GCEE compared with the brain isolated from ADR‐injected mice previously injected with saline. These results are discussed with regard to potential pharmacological prevention of brain cognitive dysfunction in patients receiving ADR chemotherapy. © 2006 Wiley‐Liss, Inc.
An effective traffic management scheme using adaptive handover time in next‐generation cellular networks
Authors: Kim Dongwook , Sawhney Mrinalini , Yoon Hyunsoo 
Published: December 2006

AbstractNext‐generation cellular networks are expected to support various multimedia services over IP networks with high spectral efficiency. In these networks, hotspot cells can occur when available wireless resources at some location are not sufficient to sustain the needs of users. The hotspot cell can potentially lead to blocked or dropped calls, which can deteriorate the service quality for users. A group of users enjoying multimedia services could move around in the networks generating heavy flows of traffic. This situation can generate a hotspot cell which has a short lifespan of only a few minutes. If there is a steady increase in the number of these users, the hotspot cell which has a short lifespan will occur more frequently in the overall service area. In this paper, we propose a handover‐based traffic management scheme which can effectively deal with hotspot cells in next‐generation cellular networks. With our scheme, the current serving cell can recognize the traffic load status of the target cell in advance, before handover execution. Then, according to the load status, it adaptively controls the handover time. The handover‐based traffic management scheme can effectively and flexibly handle hotspot cells in the networks. Acceptable service quality can also be supported as users continuously maintain communication links. In the simulation results, we find that our scheme generates a smaller number of hotspot cells and supports higher service quality than the schemes compared. Copyright © 2006 John Wiley & Sons, Ltd.
Polycondensation of activated L‐valine and L‐leucine esters with various lewis acids
Authors: Nemoto Tadamasa , Ando Daisuke , Naka Kensuke , Chujo Yoshiki 
Published: December 2006

AbstractTo develop a novel polycondensation method for the preparation of poly (amino acid)s, we screened a transition metal or a rare‐earth triflate as a Lewis acid for the polycondensation of activated amino acid esters in N,N‐dimethylformamide solutions at room temperature. The polymerizations of 4‐nitrophenyl L‐leucinate (1a) and 4‐nitrophenyl L‐valinate (1b) scarcely proceeded without any Lewis acid at room temperature. In the presence of 5 mol % metal triflates, especially scandium(III) trifluoromethanesulfonate, the polymerizations of both monomers were promoted effectively. The products, which were collected by the reaction mixture being poured into water, were recognized as poly(L‐valine)s by Fourier transform infrared spectroscopy, gel permeation chromatography analysis, and 1H NMR spectroscopy. These results showed that a metal triflate as a Lewis acid could coordinate to a carbonyl oxygen of activated L‐valinate and L‐leucinate even in a highly polar solvent, such as N,N‐dimethylformamide; therefore, the polymerizations of activated L‐valinate and L‐leucinate were promoted. Because steric hindrance derived from the isobutyl group in 1b was less than that of the isopropyl unit in 1a, the effect of the metals was not as sensitive for the polymerization of 1b. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 543–547, 2007
Structure and properties of a truely apo form of AraC dimerization domain
Authors: Weldon John E. , Rodgers Michael E. , Larkin Christopher , Schleif Robert F. 
Published: December 2006

AbstractThe arabinose‐binding pockets of wild type AraC dimerization domains crystallized in the absence of arabinose are occupied with the side chains of Y31 from neighboring domains. This interaction leads to aggregation at high solution concentrations and prevents determination of the structure of truely apo AraC. In this work we found that the aggregation does not significantly occur at physiological concentrations of AraC. We also found that the Y31V mutation eliminates the self‐association, but does not affect regulation properties of the protein. At the same time, the mutation allows crystallization of the dimerization domain of the protein with only solvent in the arabinose‐binding pocket. Using a distance difference method suitable for detecting and displaying even minor structural variation among large groups of similar structures, we find that there is no significant structural change in the core of monomers of the AraC dimerization domain resulting from arabinose, fucose, or tyrosine occupancy of the ligand‐binding pocket. A slight change is observed in the relative orientation of monomers in the dimeric form of the domain upon the binding of arabinose but its significance cannot yet be assessed. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Aquatic fulvic acid as a matrix for matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric analysis
Authors: Mugo Samuel M. , Bottaro Christina S. 
Published: December 2006

AbstractAquatic fulvic acids (AFAs) are demonstrated to be effective matrices for the analysis of various polar compounds (ranging from 100–1500 Da) by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). The efficiency of AFA as a matrix is shown for a wide range of test compounds, including a number of carbohydrates, cyclodextrins and peptides, with typical detection limits of ∼10 µg mL−1. The propensity of AFA to enhance ionization through protonation of peptides, and formation of sodium and potassium adducts of carbohydrates and polyethylene glycol, was noted. Differences were observed in the performances of the two AFA matrices used, a Suwannee River, International Humic Substances Society (IHSS) standard and a locally extracted fulvic acid (LFA). For example, in the analysis of carbohydrate standards, the use of the LFA matrix typically doubled the analyte ion signal intensities and resulted in signal‐to‐noise (S/N) ratios that were 2–4 times better than when the Suwannee River AFA matrix was used. AFA was also used in the analysis of real‐world samples without extraction or purification; cantaloupe juice and acetaminophen tablets were analyzed, and glucose and acetaminophen could easily be identified as respective components. When lower concentrations of fulvic acid were used in the presence of sugars, a reversal of roles was observed in which the sugars functioned as the matrix and significantly enhanced ionization of the AFA components, while ions associated with the sugars themselves were suppressed or absent. Effective as a matrix for a variety of analytes and widely available, AFA is an attractive environmentally friendly choice for use in MALDI applications. Copyright © 2006 John Wiley & Sons, Ltd.
The use of stable isotope ratio analyses to discriminate wild and farmed gilthead sea bream (Sparus aurata)
Authors: Rojas Jose Manuel Moreno , Serra Francesca , Giani Ivan , Moretti Vittorio M. , Reniero Fabiano , Guillou Claude 
Published: December 2006

AbstractContinuous flow isotope ratio mass spectrometry (CF‐IRMS) has been used to analyze samples of gilthead sea bream (g.s.b.) (Sparus aurata) of known geographical origin (four countries on the Mediterranean Sea) from wild and farmed sources (40 farmed and 10 wild). δ13C and δ15N values have been measured on muscle samples as these are the most informative parameters of the diet of the animals. Both stable isotopes are indicators of the origin of the fish: δ13C giving a tool to distinguish between wild and farmed g.s.b. and δ15N being more informative on the geographical origin of the fish (this fact could be related more to differences in feed mixtures given to farmed fish than to geographical reasons). The proposed methodology offers a cost‐ and time‐effective alternative to other analytical techniques in identifying wild and farmed fish. Copyright © 2006 John Wiley & Sons, Ltd.
Protein Transport and Concentration by Electrophoresis in Two-phase Microflows
Authors: Münchow G. , Hardt S. , Kutter J.P. , Drese K.S. 
Published: December 2006

This work aims at a new class of methods for electric field-mediated separation of biomolecules. In contrast to standard techniques, electrophoretic transport was not performed in a single-phase homogenous fluid, but in a system of stratified layers. The large surface-to-volume ratio characteristic for microfluidic systems allows the interactions of biomolecules with liquid/liquid interfaces to be examined and the suitability of corresponding effects for applications in the field of biomolecular separations and enrichment to be assessed. To perform these types of studies, a micro flow cell was fabricated into which two coflowing immiscible liquid phases can be introduced. Subsequently, the electrophoretic transport of biomolecules driven by an electric field perpendicular to the channel was examined. To investigate the transport phenomena related to electrophoresis in stratified two-phase systems, aqueous solutions consisting of polyethylene glycol and dextran were prepared, which allowed a stable interface to develop. Transport within one phase and an enrichment of proteins at the phase boundary has been established. In addition, other kinds of fluid combinations such as water and propylene carbonate have been examined, also supporting the enrichment of proteins at the phase boundary.
A Microcarrier‐Based Cultivation System for Expansion of Primary Mesenchymal Stem Cells
Authors: Frauenschuh Simone , Reichmann Elisabeth , Ibold Yvonne , Goetz Peter M. , Sittinger Michael , Ringe Jochen 
Published: December 2006

AbstractMicrocarrier cultures have been shown to allow extensive cell expansion of tissue engineering relevant cells, such as chondrocytes, while maintaining their phenotype. Our aim was to investigate the in vitro three‐dimensional expansion of porcine bone‐marrow‐derived primary mesenchymal stem cells (MSC) using commercially available Cytodex type 1, type 2, and type 3 microcarriers. In comparison, the Cytodex type 1 microcarriers showed the best results for adherence with over 80% adherent cells after 3 h of incubation, analyzed by the Poisson distribution. Different start cell densities ranging from 1 to 3 × 106 cells per 100 cm2 had only a minor influence on adhesion. The proliferation was examined on Cytodex type 1 microcarriers over a cultivation time of 28 days, which could reveal cell growth and proof of cells recolonizing freshly added microcarriers. Scanning electron microscopy displayed appropriate cell morphology and confirmed cell proliferation. After enzymatic harvest from microcarriers, the osteogenic and chondrogenic differentiation of these cells was induced and shown by relevant histochemistry, such as von Kossa and Alcian blue staining. Totaling the results, we have shown that the three‐dimensional expansion of MSC on microcarriers represents a beneficial alternative to the conventional two‐dimensional monolayer cultivation method.
Trafficking and phosphorylation dynamics of AQP4 in histamine‐treated human gastric cells
Authors: Carmosino Monica , Procino Giuseppe , Tamma Grazia , Mannucci Roberta , Svelto Maria , Valenti Giovanna 
Published: December 2006

Background information. AQP4 (aquaporin 4) internalization and a concomitant decrease in the osmotic water permeability coefficient (Pf) after histamine exposure has been reported in AQP4‐transfected gastric HGT1 cells.Results. In the present study we report that AQP4 internalization is followed by an increase in AQP4 phosphorylation. Histamine treatment for 30 min resulted in an approx. 10‐fold increase in AQP4 phosphorylation that was inhibited by 1 μM H89, a specific PKA (protein kinase A) inhibitor, but not by PKC (protein kinase C) and CK2 inhibitors. Moreover, measurement of PKA activity after 30 min of histamine treatment showed that PKA activity was approx. 3‐fold higher compared with basal conditions. AQP4 phosphorylation was prevented in cells treated with histamine for 30 min after pre‐incubation with PAO (phenylarsine oxide), an inhibitor of protein endocytosis. Using an endo—exocytosis assay we showed that, after histamine washed out, internalized AQP4 recycled back to the cell surface, even in cells in which de novo protein synthesis was inhibited by cycloheximide.Conclusions. Phosphorylation experiments, combined with immunolocalization studies, indicated that AQP4 phosphorylation is mediated by PKA and occurs subsequently to its internalization in late endosomes. We suggest that phosphorylation might be a mechanism involved in retaining AQP4 in a vesicle‐recycling compartment.
Visualization of cell microtubules in their native state
Authors: Bouchet‐Marquis Cédric , Zuber Benoît , Glynn Anne‐Marie , Eltsov Mikhail , Grabenbauer Markus , Goldie Kenneth N. , Thomas Daniel , Frangakis Achilleas S. , Dubochet Jacques , Chrétien Denis 
Published: December 2006

Background information. Over the past decades, cryo‐electron microscopy of vitrified specimens has yielded a detailed understanding of the tubulin and microtubule structures of samples reassembled in vitro from purified components. However, our knowledge of microtubule structure in vivo remains limited by the chemical treatments commonly used to observe cellular architecture using electron microscopy.Results. We used cryo‐electron microscopy and cryo‐electron tomography of vitreous sections to investigate the ultrastructure of microtubules in their cellular context. Vitreous sections were obtained from organotypic slices of rat hippocampus and from Chinese‐hamster ovary cells in culture. Microtubules revealed their protofilament ultrastructure, polarity and, in the most favourable cases, molecular details comparable with those visualized in three‐dimensional reconstructions of microtubules reassembled in vitro from purified tubulin. The resolution of the tomograms was estimated to be approx. 4 nm, which enabled the detection of luminal particles of approx. 6 nm in diameter inside microtubules.Conclusions. The present study provides a first step towards a description of microtubules, in addition to other macromolecular assemblies, in an unperturbed cellular context at the molecular level. As the resolution appears to be similar to that obtainable with plunge‐frozen samples, it should allow for the in vivo identification of larger macromolecular assemblies in vitreous sections of whole cells and tissues.
Alexander George Ogston. 30 January 1911–29 June 1996
Authors: Smithies O. 
Published: December 2006

For science is more than the search for truth, more than a challenging game, more than a profession. It is a life that a diversity of people lead together, in the closest proximity, a school for social living. We are members one of another.
A.G. Ogston, 1970 lecture to the Australian Biochemical Society
In 1984, at the age of 73, Alexander (‘sandy’) Ogston, with the gentle encouragement of Professor R.B. (‘David’) Fisher, F.R.S.E., as an interviewer, recorded a videotape of his life and science (now in the Biochemistry Society Archives). A few years later in 1988 he completed a more comprehensive written account in his ‘Reminiscences, 1911–1988’ (now in the Royal Society Archives). These eloquent records and a published lecture given in 1970 to the Australian Biochemical Society (17)* have provided much of the material for this memoir and are quoted or paraphrased extensively. Unannotated ‘quote's’ are from Sandy's own accounts or his papers.
Tadeus Reichstein. 20 July 1897 — 1 August 1996
Authors: Rothschild Miriam 
Published: December 2006

Tadeus Reichstein was born on 20 July 1897 in Wloclawek (in Russian Poland), the eldest of five sons of Jewish parents, Isidor Reichstein and Gustava Brochman (7)*.
In Russia, in those days, only a small number of Jews were allowed to study at the technical high school in St Petersburg, and Tadeus's father, Isidor, considered himself extremely fortunate to have been selected. He received virtually no financial support, and in order to survive embarked on an austere self-disciplined routine, limiting his daily meal to one herring, black bread and water. After a while, he managed to earn a meagre pittance giving lessons in physics and mathematics to children of wealthy citizens. Despite hard times, he won a medal for his brilliant examination papers. After leaving school, Isidor moved to Kiev in the Ukraine, where he succeeded in founding his own business as a sugar-processing engineer and was able to marry.
In 1904 the youngest brother, Paul, was born and the flat in Kiev proved too small to accommodate five boys, so Tadeus, as the eldest, was sent to live temporarily with his aunt, who was married to a Lublin pharmacist. Although only eight years old, Tadeus took a lively interest in the chemist shop, and his uncle encouraged him to assist in making pills, by rolling them by hand. On rejoining his family he turned his sleeping quarters into a ‘laboratory’ and he and a young friend spent all their spare time attempting to create silver from iron filings. It was his first attempt at alchemy.
In 1905, violent pogroms occurred in Russia and the little boy heard the screams of the victims outside in the street and saw the wounded and dying, streaming with blood, dragged into their shop, while the mounted cossacks galloped past heedlessly. Tadeus recalled the atmosphere of terror, but he had never seen blood before and he remembered he found that very interesting.
Eugene Paul Wigner. 17 November 1902 — 1 January 1995
Authors: Seitz Frederick , Vogt Erich , Weinberg Alvin M. 
Published: December 2006

Eugene Wigner was a towering leader of modern physics for more than half of the twentieth century. Although his greatest renown was associated with the research–article of symmetry theory to quantum physics and chemistry, for which he was awarded the Nobel Prize in Physics for 1963, his scientific work encompassed an astonishing breadth of science, perhaps unparalleled during his time.
In preparing this memoir, we have the impression we are attempting to record the monumental achievements of half a dozen scientists. There is the Wigner who demonstrated that symmetry principles are of great importance in quantum mechanics; who pioneered the application of quantum mechanics in the fields of chemical kinetics and the theory of solids; who was the first nuclear engineer; who formulated many of the most basic ideas in nuclear physics and nuclear chemistry; who was the prophet of quantum chaos; who served as a mathematician and philosopher of science; and the Wigner who was the supervisor and mentor of more than forty PhD students in theoretical physics during his career of over four decades at Princeton University.
The legacy of these contributions exists in two forms. First, there are the papers–in excess of 500–now included in eight volumes of his collected works (15)*. His legacy also resides in the many concepts and phenomena that bear his name. There is, for example, the Wigner–Eckart theorem for the addition of angular momenta, the Wigner effect in nuclear reactors, the Wigner correlation energy, as well as the Wigner crystal in solids, the Wigner force, the Breit–Wigner formula in nuclear physics, and the Wigner distribution in the quantum theory of chaos. is collection of essays Symmetries and reflections (14) provides an insightful view of the many intellectual matters that concerned him during a busy career. The recollections of his life recorded by Andrew Szanton when Wigner was in his eighties (Szanton 1992) provide a special insight into the circumstances of his life and the incidents that brought him to the fore.