bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions of a mammalian β‐galactoside‐binding lectin with hamster fibroblasts
Authors: Stojanovic D. , Hughes R. C. , Feizi T. , Childs R. A. 
Published: December 2004

AbstractA β‐galactoside‐binding endogenous lectin extracted from bovine heart binds to the surface of baby hamster kidney (BHK) cells. The binding to and agglutination of cells is reduced in certain ricin‐resistant mutants (Ric cells) in parallel with the decreased number of binding sites for the selective agent, ricin, a galactose‐specific plant lectin. However, clear differences in the binding specificities of bovine lectin and ricin are shown by the effect of neuraminidase. BHK cells and Ric mutant cells treated with neuraminidase bind similar amounts of the bovine lectin compared with untreated cells, and ricin binding is greatly increased.The mammalian lectin immobilised on inert glass mediates the attachment and spreading of normal BHK cells and agglutinates these cells in solution. Ricin‐resistant mutant cells respond poorly. These results are consistent with a role of endogenous lectins in cellular adhesiveness and show that cell adhesion may be regulated by the density of specific surface receptors for lectins.
Role of cholesterol in the structure and function of gastric microsomal vesicles
Authors: Ray Tushar K. , Nandi Jyotirmoy , Dannemann Andrew , Gordon Gerald B. 
Published: December 2004

AbstractDigitonin was used as a tool to investigate the organization and function of cholesterol in gastric microsomes. Microsomal vesicles were treated with digitonin for different time at 0–4°C under isotonic conditions. The effects of digitonin treatment of the vesicles on removal of cholesterol, ultrastructural changes, (H+ + K+)‐ATPase activity, and gastric ATPase‐dependent H+ uptake ability were investigated. Microsomal cholesterol was extracted in an exponential manner with a t1/2 of 32 min. There was no release of microsomal phospholipids by digitonin treatment during the same period. Digitonin treatment (30 min) produced visible “holes” in the vesicles; at the same time (H+ + K+)‐ATPase‐dependent H+ uptake was abolished. Under the same conditions the K+‐stimulated ATPase activity, however, was moderately (about 35%) reduced, although the response of K+ stimulation to valinomycin was obliterated. Longer digitonin treatment resulted in gradual diffusion and eventual disappearance of the “holes” with the generation of distorted cup‐shaped microsomes. The data strongly suggest that membrane lipids are freely mobile and that there is a certain degree of specialization in the organization of gastric microsomal cholesterol for the proper maintenance of the membrane structure and function.
Adipocyte insulin‐binding species: The size and subunit composition of the larger binding species
Authors: Goren H. Joseph , Elliott C. , Dudley R. A. 
Published: December 2004

AbstractSeveral investigators have reported that there are both large and small insulinbinding proteins in plasma membranes; the larger protein demonstrates nonlinear Scatchard binding, and the smaller protein has linear binding. We now present evidence that the larger insulin‐binding species consists of four proteins of different sizes. Rat epididymal adipocyte plasma membranes were prebound with 125I‐insulin and then exposed to 1 mM disuccinimidyl suberate for 15 min at 2°C. The membranes were solubilized in 0.1% Triton X‐100 and applied to a Sepharose 6B column. Peaks of radioactivity from the column were dialyzed, lyophilized, and analyzed by dodecyl‐sulphate gel electrophoresis (5%, 100/1; mono/bisacrylamide). Autoradiograms of the gels were scanned with a densitometer. The Sepharose chromatogram revealed four radioactive peaks: peak 1 at column void volume; peak 2, Kav = 0.27; peak 3, Kav = 0.77; and peak 4, Kav = 1.09. Dodecyl sulphate electrophoresis of fractions in peak 2 demonstrated four bands on autoradiography; peak 1 did not enter the gel and peaks 3 and 4 ran with the dye front. Molecular weight estimates of the four insulin‐binding species in peak 2 were 600, 500, 420, and 350 K. On dithiothreitol reduction each insulin‐binding species yielded subunits of Mr ≅ 135 and 18 K. The three largest binding species demonstrated an additional 45‐K dalton protein on dithiothreitol reduction, and the 500‐K and 420‐K binding species also yielded a 49‐K dalton protein. These results suggest that the large insulin‐binding protein in rat epididymal adipocytes contains several insulin‐binding species, and that these insulin‐binding species differ in the number of and the type of subunits they contain. In addition, it may be postulated that the nonlinear Scatchard binding associated with the larger binding protein is a consequence of the heterogeneity of the insulin‐binding species in this Sepharose peak.
Mice immunized to insulin develop antibody to the insulin receptor
Authors: Shechter Yoram , Elias Dana , Maron Ruth , Cohen Irun R. 
Published: December 2004

AbstractWe immunized mice with insulin and found that those strains that develop insulin antibodies subsequently produce insulin‐like activity in amount equivalent to 300–400 ng insulin per ml serum. The activity was due exclusively to IgG2 antibodies. Bioactivity could be blocked efficiently by insulin antibodies from guinea pigs and from mice. The active IgG2 also displaced labeled insulin from fat cells. Preliminary in vivo studies have indicated that the appearance of insulin‐like antibodies in the mouse resulted in abnormal glucose homeostasis and “down regulation” of insulin receptors. These results indicate that immunization to insulin can initiate an idiotype‐anti‐idiotype network resulting in antibodies to the hormone receptor.
Immunological studies of β‐adrenergic receptors
Authors: Couraud P. O. , Lu B. Z. , Schmutz A. , Durieu‐Trautmann O. , Klutchko‐Delavier C. , Hoebeke J. , Strosberg A. D. 
Published: December 2004

AbstractTwo types for antibodies have been raised against the β‐adrenergic receptor: either by injection of highly purified receptor from turkey erythrocytes or by injection of anticatecholamine ligand antibodies, and induction of anti‐idiotypic antibodies Our data illustrate the interactions of the β‐adrenergic receptor with these polyclonal antibodies. Preliminary results with monoclonal antibodies are also described. The redistribution of β‐receptors on intact cells is visualized by the use of fluorescent antibodies. Immunoprecipitation of radioiodinated receptor by the antireceptor antibodies yields a single major 60,000 MW component.
The orientation of insulin receptors in the red cell membrane
Authors: Baumann Gerhard , Abramson Edith C. , Drobny Elaine C. 
Published: December 2004

AbstractHigh‐affinity binding of insulin to receptors in human erythrocyte membranes occurred at the external surface, but not at the cytoplasmic surface of the plasma membrane, as assessed by insulin binding to right‐side‐out and inside‐out membrane vesicles. Even after prolonged (3 h) incubation at 22°C, binding at the cytoplasmic membrane aspect remained negligible. The data indicate that the insulin receptor displays its hormone‐binding site exclusively toward the extracellular space and that transmembrane mobility (“flip‐flop”) of the receptor from one to the other membrane leaflet is severely restricted.
Butyrate inhibits mouse fibroblasts at a control point in the G1 phase
Authors: Wintersberger Erhard , Mudrak Ingrid , Wintersberger Ulrike 
Published: December 2004

AbstractButyrate block 3T6 cells in the G1 phase of the cell cycle approximately 5–6 h prior to the start of the S phase. Serum factors are required before as well as after the butyrate‐sensitive steps in G1 in order to allow cells to start DNA synthesis. 3T6 cells infected with SV40 or with polyoma virus are also blocked at the same stage in G1 in the presence of the fatty acid. However, events before as well as after the butyrate‐sensitive step do not require serum in virus‐infected cells. The sensitivity of the initiation of cellular DNA synthesis to increasing concentrations of butyrate is the same for serum‐stimulated or for virus‐infected cells. A similar and parallel effect on DNA synthesis is observed if cells are incubated in the presence of very small amounts of cycloheximide. After release of the cycloheximide‐induced G1 arrest about 4–6 h have to pass before cells enter the S phase. Cells stably transformed by SV40 are considerably more resistant to low cycloheximide concentrations and to butyrate. These data are discussed in the light of the hypothesis that both low concentrations of cycloheximide and sodium butyrate block cells at a control point in G1 by interference with the synthesis of one or more rapidly turning over, cell cycle‐specific proteins.
A plasmodium protein kinase that is developmentally regulated, stimulated by spermine, and inhibited by quercetin
Authors: Wiser Mark F. , Eaton John W. , Sheppard J.R. 
Published: December 2004

AbstractPlasmodium berghei–infected murine red cells possess protein kinase activity that is associated with the isolated parasites. Schizonts contain significantly higher levels of this protein kinase than the more immature forms, suggesting a relationship between this enzyme activity and parasite development. Partially purified protein kinase has a Km for ATP of ∼30 μM, whereas the Km for GTP is ∼300 μM and the substrate preference is phosvitin > casein > > histone > protamine. The Mg2+ optimum is 10–20 mM, and the protein kinase activity is stimulated by the polyamines spermine and spermidine. The flavone, quercetin, inhibits the protein kinase activity in a competitive manner with' respect to ATP (Ki ∼3 μM), and P chabaudi also has a very similarly regulated protein kinase. Protein kinases from both species are very similar to the type I casein kinase.
Suicide gene therapy with an adenovirus expressing the fusion gene CD::UPRT in human glioblastomas: different sensitivities correlate with p53 status
Authors: Bourbeau Denis , Lavoie Geneviève , Nalbantoglu Josephine , Massie Bernard 
Published: December 2004

AbstractBackgroundSeveral gene therapy strategies have been designed for cancer treatment. Intra‐tumoral injection of adenoviruses expressing pro‐drug‐converting enzymes is one such strategy. Although the efficacy of these therapies was tested in animal models, little work has been devoted to the determination of critical variables for success. In this work, we aimed at better understanding variables that affect the cytosine deaminase::uracil phosphoribosyl transferase (CD::UPRT)‐based strategy in two human glioblastomas.MethodsWe have constructed two adenoviruses expressing either CD or the fusion protein CD::UPRT. We have tested their anti‐tumor activity in combination with 5‐fluorocytosine (5‐FC) in the glioblastoma cell lines U87 and U251, which are p53‐wt and p53‐deficient, respectively. Anti‐tumor activity has also been investigated in spheroid structures.ResultsThe superiority of CD::UPRT over CD was confirmed in both glioblastoma cells. We found that the pro‐drug concentration required for anti‐tumor activity was 9‐fold higher in U251 than in U87, while multiplicity of infection (MOI) as low as 6 was sufficient to achieve 50% killing. Bystander activity was observed with as few as 2 and 6% transduced cells for U87 and U251, respectively. Differences in sensitivity between U87 and U251 were not due to differences in transduction, transgene expression, or intercellular transport, but were related to 5‐FU sensitivity and p53 status. Also, it is noteworthy that, in contrast to U87, U251 spheroids barely responded to the treatment, whereas their monolayer counterparts were very sensitive.ConclusionsOur study has shown that p53 status is important for CD::UPRT/5‐FC treatment. Moreover, this study demonstrated that the three‐dimensional spheroid model is a more stringent in vitro model for suicide gene therapy evaluation than are monolayer cultures. Copyright © 2004 John Wiley & Sons, Ltd.
Miniaturized system of a gas chromatograph coupled with a Paul ion trap mass spectrometer
Authors: Shortt B. J. , Darrach M. R. , Holland Paul M. , Chutjian A. 
Published: December 2004

AbstractMiniature gas chromatography (GC) and miniature mass spectrometry (MS) instrumentation has been developed to identify and quantify the chemical compounds present in complex mixtures of gases. The design approach utilizes micro‐GC components coupled with a Paul quadrupole ion trap (QIT) mass spectrometer. Inherent to the system are high sensitivity, good dynamic range, good QIT resolution, low GC flow‐rates to minimize vacuum requirements and the need for consumables; and the use of a modular approach to adapt to volatile organic compounds dissolved in water or present in sediment. Measurements are reported on system response to gaseous species at concentrations varying over four orders of magnitude. The ability of the system to deal with complicated mixtures is demonstrated, and future improvements are discussed. The GC/QIT system described herein has a mass, volume and power that are, conservatively, one‐twentieth of those of commercial off‐the‐shelf systems. Potential applications are to spacecraft cabin‐air monitoring, robotic planetary exploration and trace‐species detection for residual gas analysis and environmental monitoring. Copyright © 2004 John Wiley & Sons, Ltd.
Mass spectrometry in the study of anthocyanins and their derivatives: differentiation of Vitis vinifera and hybrid grapes by liquid chromatography/electrospray ionization mass spectrometry and tandem mass spectrometry
Authors: Mazzuca Pierluca , Ferranti Pasquale , Picariello Gianluca , Chianese Lina , Addeo Francesco 
Published: December 2004

AbstractA mass spectrometric‐based procedure for anthocyanin profiling was set up to distinguish authentic Vitis vinifera from hybrid red grapevine cultivars. 3‐O‐Monoglucoside and the related acetyl‐, p‐coumaryl‐ and caffeoyl‐monoglucoside anthocyanins occurred only in Vitis vinifera, whereas 3,5‐O‐diglucoside and the substituted acetyl‐, p‐coumaryl‐, feruloyl‐ and caffeoyl‐diglucoside anthocyanins were the additional pigments in hybrid grapevines. The procedure was applied expressly to identify red grape cultivars based on the anthocyanin chemo‐type determination. In particular, a red grape cultivar, having 3,5‐O‐diglucoside anthocyanins and a novel class of anthocyanin monoglucosides, such as cyanidin‐3‐O‐, cyanidin‐3‐O‐(6‐O‐acetyl)‐ and cyanidin‐3‐O‐(6‐O‐p‐coumaryl)pentoside, was classified as hybrid. A second vine cultivar, characterized exclusively by 3‐O‐monoglucoside anthocyanins, was included among the Vitis vinifera species. Anthocyanin profiling by mass spectrometry could represent the core of a chemotaxonomic procedure for distinguishing American and European grapevines based on the identification of post‐synthetic anthocyanidin modification. Copyright © 2004 John Wiley & Sons, Ltd.
Multilayer Films Fabricated from Oppositely Charged Polyphenylene Dendrimers by Electrostatic Layer‐by‐Layer Assembly
Authors: Kim Dong Ha , Hernandez‐Lopez Jose Luis , Liu Jianyun , Mihov George , Zhi Linjie , Bauer Roland E. , Grebel‐Köhler Dörte , Klapper Markus , Weil Tanja , Müllen Klaus , Mittler Silvia , Knoll Wolfgang 
Published: December 2004

AbstractSummary: Assemblies of oppositely charged L‐lysine/carboxylic acid functionalized polyphenylene dendrimers and hybrid multilayers of L‐lysine dendrimers/colloidal gold nanocrystals were fabricated as alternate multilayers on 3‐mercaptopropionic acid coated gold surfaces via layer‐by‐layer deposition. The fabrication of the multilayer films was monitored by kinetic and scan mode surface plasmon resonance spectroscopy. The permeability properties of the dendritic polyelectrolyte layers were characterized by electrochemistry in the presence of [Fe(CN)6]3−/4− as the redox couple. A high interfacial charge‐transfer resistance, originating from the electrostatic repulsion of the negatively charged redox couple against the negatively charged interface was observed and the charge‐transfer resistance found to increase with increasing number of layers.3D‐structure of the investigated polyphenylene dendrimers: a) G2(L‐lysine)8 and b) G2(COOH)16.magnified image3D‐structure of the investigated polyphenylene dendrimers: a) G2(L‐lysine)8 and b) G2(COOH)16.
Interfacial Behavior of a Reacting Alkoxysilane Monolayer System
Authors: Carino Stephen R. , Duran Randolph S. 
Published: December 2004

AbstractSummary: We report here the results on the investigations of the dynamic interfacial behavior of a trifunctional alkoxysilane, octadecyltrimethoxysilane (OTMS) as it is reacting at the air‐water interface. We have investigated both the Π‐A isotherms and A(t) isobars of OTMS at acidic subphases. An attempt to analyze the kinetics of the reaction in the monolayer was limited to the early stages of the reactions and only describes the kinetics of hydrolysis. We also confirmed by rheological measurements that this system does indeed form a network inefficiently and the resulting structure most likely consists of extensive linear segments as has been suggested in earlier reports. The general rheological characteristic indicates the product to have high molecular weight. The product also exhibited a 2D sol‐gel transition that has general features of a percolating network. However, the scaling behavior does not follow exactly that predicted; several reasons for this are discussed.A(t) isobars of OTMS at various subphase pHmagnified imageA(t) isobars of OTMS at various subphase pH
Defining mitogen‐activated protein kinase pathways with mass spectrometry‐based approaches
Authors: Powell David W. , Pierce William M. , McLeish Kenneth R. 
Published: December 2004

AbstractMitogen‐activated protein kinases are a group of ubiquitously expressed kinase pathways that have been conserved from yeast through humans. They control a large number of critical cell functions. Identification of targets of those kinases is necessary to define signal transduction pathways that lead to cell responses. The application of a number of mass spectrometry‐based techniques to the identification of phosphoproteins is reviewed. A new proteomic approach is described for the identification of the downstream targets of specific kinases that combines phosphorylation of cell lysates in in vitro kinase reactions by active recombinant kinase with protein separation by two‐dimensional (2D) gel electrophoresis or SDS–PAGE and phosphoprotein identification by MALDI‐TOF mass spectrometry or by phosphopeptide enrichment and tandem mass spectrometry. The results suggested that a combination of multiple approaches will be required to fully identify phosphoproteomes. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:847–864, 2005
Beurteilung des Motorenverschleißes zur Bewertung von Motorenölen
Authors: Bartz W. J. , Müller K. 
Published: December 2004

AbstractBei der Beurteilung des Verschleißverhaltens von Motorenölen ist infolge des komplexen Verschleißvorganges in Verbrennungsmotoren die objektive Bestimmung eines absoluten Verschleißmaßes besonders erschwert. Dies gilt vor allem für den Zylinderverschleiß, da es oft unmöglich ist, Verschleiß und Verformung eindeutig voneinander zu trennen. Da die Richtung des maximalen Verschleißes bei verschiedenen Versuchen nicht exakt gleich bleiben muß und es bei Vergleichsmessungen nicht leicht ist, stets die gleiche Meßstelle exakt einzuhalten, sollten möglichst Rundummessungen und Mantellinienmessungen vorgenommen werden, um daraus auf den Maximalverschleiß zu schließen. Deshalb sind bei der Festlegung eines zulässigen Maximalverschleißes in Spezifikationen Toleranzen anzugeben, da in Grenzfällen sonst eine ungerechte Einordnung der Öle nicht ausgeschlossen werden kann.
Anwendungsmöglichkeiten des Pulvernitrierens im Vergleich zum Badnitrieren (Tenifer‐Verfahren)
Authors: Kurz Rudolf 
Published: December 2004

AbstractDas Pulvernitrieren beruht auf der thermischen Zersetzung von Kalkstickstoff. Es ist ein einfaches Verfahren, das im Gegensatz zum Badnitrieren keine aufwendigen Einrichtungen erfordert. Es können nur kleine Teile pulvernitriert werden. Einer Badnitrierdauer von 90 min entspricht eine Pulvernitrierung von ca. 5 Stunden. Wie beim Badnitrieren bildete sich auf der Oberfläche der nitrierten Stähle eine Verbindungszone und eine Diffusionszone aus. Die Verbindungszone pulvernitrierter Teile war porenfrei.
Anreicherung von Spurenelementen zur Atomabsorptionsspektralanalyse
Authors: Prugger H. , Kling O. 
Published: December 2004

AbstractZum Nachweis von Spurenelementen mit der Atomabsorptions‐analyse werden je nach Probenart und Menge verschiedene Anreicherungsverfahren vorgeschaltet. Hierzu gehören die selektive Volumeneinengung durch Extraktion und Ionenaustauscher sowie die Mitfällung im Bereich sehr niedriger Konzentration. Für die Spurenanalyse an Mikromengen haben sich besondere Verdampfungseinrichtungen anstelle der konventionellen Technik mit Zerstäuber und Flamme bewährt. Im einzelnen werden Zeitaufwand, Präzision und Nachweisgrenzen der wichtigsten Verfahren vergleichsweise diskutiert und an Hand eigener Ergebnisse erläutert.
Prüfung und Ausbesserung von Apparateemaillierungen
Authors: Eisner Joachim. H. 
Published: December 2004

AbstractDie im Apparatebau zur Beurteilung der Güte von Emaillierungen gebräuchlichen Prüfverfahren und die für Chemie‐Emaillierungen üblichen Ausbesserungsverfahren werden beschrieben.
Die Bedeutung der Werkstoffauswahl für die Gebrauchstauglichkeit von Chemieapparaten Auswahlkriterien und Prüfverfahren
Authors: Gräfen H. , Gerischer K. , Horn E.‐M. 
Published: December 2004

AbstractWerkstoffauswahl und konstruktive Planung – Betriebstemperatur und mechanische Beanspruchbarkeit – Verarbeitbarkeit – Beständigkeit gegenüber Korrosion und Verschleiß – Korrosionsprüfverfahren – Prüfung des Korrosionsverhaltens von Schweißverbindungen.
Ergebnisse von Untersuchungen zur Bauteilzähigkeit
Authors: v. Meysenbug C.‐M. , Gaube E. , Gramberg P. , Dickhäuser M. 
Published: December 2004

AbstractDie Untersuchungen an Modellbehältern aus Kesselblechen und aus Tieftemperaturstahl, über die in früheren Veröffentlichungen schon berichtet worden ist, werden abschließend ausgewertet und zu den Werkstoffeigenschaften in Beziehung gesetzt. Dabei ergibt sich, daß für das Berstverhalten der Behälter (Bauteilzähigkeit) Bereiche unterschieden werden können, für die gängige Werkstoffkennwerte (Rißauffangtemperatur und Kerbschlagübergangstemperatur) charakteristische Grenzwerte darstellen. So erhält der Anwender einen Überblick über die zu erwartenden Bruchformen.
Einfluß der Hartstoffkomponenten auf einige Eigenschaften von Hartmetallen unter besonderer Berücksichtigung neuerer Werkstoffentwicklungen
Authors: Grewe H. 
Published: December 2004

AbstractIn den folgenden Ausführungen werden einige die Anwendungstechnik interessierende Eigenschaften von Hartmetallen diskutiert. Zunächst wird bei den konventionellen Hartmetallen die Wirkungsweise von Wolframkarbid, Titankarbid und Tantalkarbid beschrieben, wobei auf die Möglichkeiten der linearanalytischen Strukturuntersuchung in Verbindung mit Standzeitversuchen hingewiesen wird. Das Gebiet der heute neben den konventionellen Hartmetallen marktgängigen Sonderwerkstoffe mit karbidischer Hartstoffphase wird knapp beleuchtet. Besonders werden die neueren Werkstoffentwicklungen auf dem Gebiet der Verbundschneidstoffe berücksichtigt.