bluuebunny/crossref_metadata_2025_split huggingface dataset:
Binding of the lipid peroxidation product 4‐hydroxynonenal to human polymorphonuclear leukocytes
Authors: Curzio M. , Ferretti C. , Stephens R. J. , Esterbauer H. , Dianzani M. U. 
Published: May 2005

Abstract4‐Hydroxynonenal (HNE) is produced during peroxidation of polyunsaturated fatty acids. It exerts a chemokinetic effect on human polymorphonuclear leukocytes (PMN). Investigations of this mechanism were performed. The results indicate that [3H]‐HNE binding to PMN results both in non‐specific bonds to the numerous SH groups of the cells and in binding to a saturable, reversible and specific HNE site. Scatchard analysis revealed that this is a single site with an apparent affinity constant of 319 nM and a density of 1·57 pmol (106)−1 cells. This specific binding site may be involved in the chemokinetic effect of HNE.
Sperm phospholipid methyltransferase activity during preparation for exocytosis
Authors: Llanos Miguel N. , Ronco Ana María 
Published: May 2005

AbstractThe present report describes experiments to evaluate phospholipid methyltransferase activity in golden hamster spermatozoa incubated under different conditions. Washed cauda epididymal sperm were incubated with taurine, in the presence or absence of epinephrine. At various times, the sperm were separated, and phospholipid methyltransferase activity measured. Also, at each time, aliquots of the sperm suspension were assayed for motility, and acrosome reactions. Some sperm incubated in the presence of taurine and epinephrine were capacitated by 3·5 h, because about 40 per cent of them can undergo the acrosome reaction 10 min after addition of the fusogen lysophosphatidylcholine. In epinephrine‐free incubations the fusogen failed to stimulated acrosome reactions. On the other hand, epinephrine stimulated by twofold phospholipid methyltransferase activity from ‘0 time’ incubated sperm, in comparison to that observed in taurine‐treated cells. Enzyme activities from both taurine or epinephrine plus taurine‐treated cells decreased as the incubation time of the sperm suspension increased. Kinetic properties of the sperm phospholipid methyltransferase acvity were modified by the presence of taurine and epinephrine when S‐adenosylmethionine was used as the substrate. These results suggest that refined molecular events occur in the sperm cell during the acquisition of fertilizing ability.
Effects of β1‐integrin antisense phosphorothioate‐modified oligonucleotide on myoblast behaviour in vitro
Authors: Carraro U. , Bruson A. , Catani C. , Libera L. Dalla , Massimino M. L. , Rizzi C. , Rossini K. , Sandri M. , Cantini M. 
Published: May 2005

AbstractMyoblasts gene‐engineered in vitro and then injected in vivo are safe, efficient options for gene therapy. While isolation of satellite cells is routinely achieved, their proliferation potential in vitro remains a limiting factor for cell transplantation under clinical conditions. We have studied the role of reversible inhibition of gene expression by antisense oligonucleotides on the proliferation of the myogenic cells. Addition of antisense oligonucleotides to myoblast cultures has been used to inhibit specifically the expression of the β1‐integrin subunit gene. Here we show that the effects of multiple pulses of a phosphorothioate oligodeoxinucleotide antisense on the attachment to substrata and on the proliferation of myoblasts are dose‐dependent. The addition of antisense to rat myoblasts caused rounding up of the cells and most of the cells became detached after several days in culture. A single pulse did not show any consistent effect, while in the presence of continously administered antisense, the relative numbers of myoblasts in the treated muscle culture increased. We have no evidence of inhibition of myoblast fusion under these conditions. On the other hand, [3H]‐TdR incorporation, total DNA and total number of cells decreased in antisense‐treated cultures thus demonstrating an inhibitory effect of the phosphorothioate oligonucleotides on DNA synthesis. These side‐effects could be overcome by substituting the phosphorothioate by unmodified oligonucleotides, so decreasing the half‐life of the antisense, but also its toxicity. The overall results suggest a potential role of integrin antisense strategy in modulating the potential of myoblasts to proliferate.
Protein synthesis in the hypertrophied heart of spontaneously hypertensive rats and a comparison of the effects of an ACE‐inhibitor and a calcium channel antagonist
Authors: Patel V. B. , Siddiq T. , Richardson P. J. , Preedy V. R. 
Published: May 2005

AbstractThe aim of the investigation was to assess and compare the effects of a calcium channel antagonist, (i.e. amlodipine) and an ACE‐inhibitor (i.e. lisinopril) in reducing chronic left ventricular hypertrophy in 15‐week old spontaneously hypertensive rats (SHR). Changes in cardiac hypertrophy were assessed after 8 weeks by measuring the fractional rates of protein synthesis using a ‘flooding dose’ of [3H]‐phenylalanine for 10 min. Blood pressure was monitored throughout the treatment period in both SHR and Wistar‐Kyoto control rats (WKY). The results showed a decrease in blood pressure by amlodipine after 1 week of treatment which was further reduced at 4 to 8 weeks. Lisinopril caused immediate and sustained reductions in blood pressure (190 mmHg to 130 mmHg, P < 0·001). After 8 weeks of treatment in SHR rats, amlodipine had no significant effect on left ventricular weight (P > 0·05), whereas lisinopril caused a marked reduction. The protein content and RNA were also not changed by amlodipine. In contrast, lisinopril significantly lowered the tissue protein, RNA and DNA content (P < 0·001). The changes in the left ventricles of lisinopril‐treated SHR rats were accompanied by an increase in the fractional synthesis rate of left ventricular myofibrillar proteins (+12 per cent, P < 0·025). The synthesis rate per unit RNA was also increased in right ventricular tissue of lisinopril‐treated SHR rats. However, amlodipine had no effect on the fractional synthesis rates of any of the left‐ventricular fractions of SHR rats (P > 0·05). The cellular efficiency in the right ventricle was also increased in amlodipine‐treated SHR rats, indicating a moderate effect on protein metabolism. In conclusion, amlodipine had minimal effects in the reduction of established left ventricular hypertrophy (LVH), despite reducing the blood pressure, whereas lisinopril caused regression of LVH. These events were associated with small changes in protein synthesis rates, with the contractile protein showing an increase.
Glutathione reductase (EC 1.6.4.2.) in experimental trypanosomiasis
Authors: Nok Andrew J. , Onyenekwe Paul C. , Ibrahim Sani , Bature Asabe , Ogbadoyi Emmanuel 
Published: May 2005

AbstractThe activity of glutathione reductase (GHSR) in extracts of kidney, liver and testis of rats infected with Trypanosoma congolense decreased with every wave of parasitemia. The implications of these observations as they relate to the risk of oxidative stress are discussed.
Glucocorticoid‐induced changes in liver: Inhibition of nuclear Ca2+, Mg2+‐dependent endonuclease activity in response to dexamethasone administration
Authors: Goodlad George A. J. , Clark Catherine M. 
Published: May 2005

AbstractThe endogenous Ca2+, Mg2+‐dependent endonuclease activity in nuclei from livers of rats receiving daily injections of the synthetic glucocorticoid dexamethasone was examined with respect to the production of both single and double strand breaks in chromatin DNA. The ability to form single strand breaks was measured by means of a nick translation assay and double strand breaks by following the appearance of nucleosomal ladders. A fall in the activity causing double strand breaks to approximately 50 per cent of the control value was apparent at 12 h after the first injection of the steroid. A fall of 25–30 per cent was also observed in the nicking activity but this was not apparent until 24 h after the first steriod injection. Both endonuclease activities remained at these lower levels for the remainder of the period of treatment. Nuclear extracts from dexamethasone‐treated rats also showed a reduced ability to produced nucleosomal ladders when incubated with rat muscle nuclei, indicating that the inhibition observed in intact nuclei from treated animals was independent of any changes in chromatin structure. On the other hand the nick translation activity of the two extracts was the same when calf thymus DNA was used as the substrate suggesting that steriod‐induced alterations in chromatin structure may be a critical factor in the reduced level of this activity observed in intact nuclei.
Cooperation of protein disulfide isomerase and redox environment in the regulation of NF‐κB and AP1 binding to DNA
Authors: Clive Diana R. , Greene James J. 
Published: May 2005

AbstractMost transcription factors are multimeric complexes whose subunits depend on strict conformational requirements to form the active unit. Among these requirements is the presence of appropriate sulfhydryl interactions that are critical to transcription factor binding to cognate DNA recognition sites. Our experiments now suggest that modulation of these sulfhydryls may involve the action of thiol‐modifying oxido‐reductases such as protein disulfide isomerase (PDI). Electrophoretic mobility shift titration experiments incorporating different ratios of GSH:GSSG indicated that changes in GSH and GSSG concentrations corresponding to redox potential differences of as little as ±15 mV enabled or abolished binding of NF‐κB and AP1 to their cognate DNA sites. Moreover, this binding range was modulated significantly by the addition of purified protein disulfide isomerase (PDI). Collectively, these results suggest that a reversible oxidation/reduction signalling pathway may exist in the cell whereby localized changes in redox potentials and/or oxido‐reductase activity can be functionally relevant in the regulation of critical gene expression events.
Modulation of murine osteoarthritis
Authors: Chayen J. , Bitensky Lucille , Chambers M. G. 
Published: May 2005

AbstractUp to nine out of 10 male STR/ORT mice develop osteoarthritis (OA) of the medial tibial cartilage at an early age. This has now been shown to be related to changes in the activity and distribution of monoamine oxidase which is related to the metabolism of catecholamines. Treatment with diclofenac sodium tended to normalize this activity but there was no significant histological improvement. It was therefore postulated that two influences were involved in the development of OA: a cellular and an extracellular factor. The first was improved by diclofenac sodium; the second, namely oedema of the matrix, was improved by tribenoside. In very preliminary studies, feeding the two drugs simultaneously resulted in 7/9 mice having no sign of OA.
JAR human placental choriocarcinoma cells actively synthesize, take up and release polyamines
Authors: Fontana L. , Cravanzola C. , Colombatto S. , Grillo M. A. 
Published: May 2005

AbstractUptake of polyamines has been investigated extensively in many cells, but not in placenta, where the polyamine– polyamine oxidase system is supposed to have an immunoregulatory function in pregnancy. Due to the importance of the transfer in this tissue, we have started this study. JAR human placental choriocarcinoma cells in monolayer at confluency were used as a model for measuring the key enzymes of polyamine synthesis and interconversion, rate of uptake and efflux, and the polyamine content. Polyamines were taken up by JAR cells and released by an independent mechanism. Ornithine decarboxylase and spermidine acetyltransferase activities and the rate of transport in and out of the cell were much higher than in other cells, such as L1210 cells. However the systems used for uptake and release appear in many respects to be similar to those observed in L1210 cells, but different from others. The uptake appears to be regulated by an inhibitory protein. Moreover, protein kinase C appears to be involved in the process. The efflux also is regulated as in L1210 cells, through control of H+ and Ca2+ concentration. In conclusion, this study shows that, in JAR cells, ornithine decarboxylase and spermidine acetyltransferase activities were much higher than in other cells, and so was the rate of transport in and out of the cells. As a result, a much higher polyamine content was observed.
Discrepancy between the initial DNA damage and cell survival after camptothecin treatment in two murine lymphoma L5178Y sublines
Authors: Grądzka Iwona , Szumiel Irena 
Published: May 2005

AbstractTwo L5178Y (LY) murine lymphoma cell sublines, LY‐R, resistant, and LY‐S, sensitive, to X‐irradiation display inverse cross‐sensitivity to camptothecin (CPT): LY‐R cells were more susceptible to this specific topoisomerase I inhibitor than LY‐S cells. After 1 h incubation with CPT, the doses that inhibited growth by 50 per cent (ID50) after 48 h of incubation were 0·54μM for LY‐R cells and 1·25 μM for LY‐S cells. Initial numbers of DNA–protein crosslinks (DPCs) measured at this level of growth inhibition were two‐fold higher in LY‐R (5·6 Gray‐equivalents) than in LY‐S cells (3·1 Gray‐equivalents), which corresponds well with the greater in vitro sensitivity of Topo I from LY‐R cells to CPT.1,2 Conversely, the initial levels of single‐strand DNA breaks (SSBs) and double‐strand DNA breaks (DSBs) were lower in LY‐R cells (4·2 Gray‐equivalent SSBs and 5·8 Gray equivalent DSBs) than in LY‐S cells (8·0 Gray‐equivalent SSBs and 12·0 Gray‐equivalent DSBs). Dissimilarity in the replication‐dependent DNA damage observed after 1 h of treatment with CPT was not due to a difference in the rate of DNA synthesis between the two cell lines, but may have arisen from a substantially slower repair of DNA breaks in LY‐S cells.3 Release from G2 block by caffeine co‐treatment significantly increased cell killing in the LY‐S subline, and only slightly inhibited growth of LY‐R cells. These results show that after CPT treatment cells arrest in G2, allowing them time to repair the long‐lived DSBs. As LY‐S cells are slower in repairing the DSBs, they were more susceptible to CPT in the presence of caffeine.
The control of mitochondrial respiration in yeast: A possible role of the outer mitochondrial membrane
Authors: Ahmadzadeh Mojgan , Horng Andrew , Colombini Marco 
Published: May 2005

AbstractMitochondrial respiration in yeast (S. cerevisiae) is regulated by the level of glucose in the medium. Glucose is known to inhibit respiration by repressing key enzymes in the respiratory chain. We present evidence that the early events in this inhibition include the closure of VDAC channels, the primary pathway for metabolite flow across the outer membrane. Aluminum hydroxide is known to inhibit the closure of VDAC. Addition of aluminum acetylacetonate to yeast cells, which should elevate the aluminum hydroxide concentrations in the cytoplasm, caused the inhibition of cell respiration by glucose to be delayed for up to 100 min. No significant effect of aluminum was observed in cells grown on glycerol. Yeast cells lacking the VDAC gene were also unresponsive to the addition of aluminum salt in the presence of glucose. Therefore, the closure of VDAC channels may be an early step in the inhibition of the respiration of yeast by glucose.
Carboxymethylated beta‐1,3‐glucan inhibits the binding and degradation of acetylated low density lipoproteins in macrophages In Vitro and modulates their plasma clearance In Vivo
Authors: Dushkin Michail I. , Safina Alfija F. , Vereschagin Evgenij I. , Schwartz Yakov Sh. 
Published: May 2005

AbstractIn atherosclerotic lesions, macrophages are transformed into foam cells accumulating modified low density lipoproteins (LDL) via the scavenger receptor pathway. We have investigated the effects of carboxymethylated beta‐1,3‐glucan (CMG) on acetylated LDL (AcLDL) metabolism in murine peritoneal macrophages in vitro and upon the clearance of AcLDL by rat liver in vivo. In cultured murine peritoneal macrophages, CMG reduced substantially the AcLDL‐induced synthesis of cholesteryl esters, decreased the binding and degradation of [125I]‐AcLDL in a dose‐dependent manner with complete inhibition at 20–30 nM, but had no effect on the binding and degradation of native [125I]–LDL. In contrast, other polysaccharides studied, namely zymosan, lipopolysaccharide, non‐modified glucan and mannan Rhodexman, had a slight effect at concentrations significantly exceeding the concentrations of CMG. [125I]‐AcLDL injected intravenously into rats was cleared from the blood with a half‐life of 3.7 min. About 56 per cent of the label of injected [125I]‐AcLDL was recovered in the liver 15 min after administration. Co‐injection of the labelled AcLDL with CMG (25 mg kg−1 b.w.) decreased the rate of AcLDL clearance so that the half‐life increased to 6.0 min. Injections of CMG (25 mg kg−1 b.w.) 48 and 24 h before the determination increased the rate of [125I]‐AcLDL clearance (with a half‐life of about 2.3 min) and increased the uptake of AcLDL by the liver. We suggest that CMG competed with AcLDL for scavenger receptors in vitro and in vivo and repeated CMG injections before the measurements of AcLDL resulted in the induction of scavenger receptor function.
Target factor analysis of parameters influencing solute‐monomeric stationary phase interactions
Authors: Howery Darryl G. , Soroka Joseph M. 
Published: May 2005

AbstractRetention indices for 18 monomeric stationary‐phase solvents and 33 organic solutes are factor analyzed. Six factors reproduce the data matrix near experimental error. The solvents diglycerol and zonyl E‐7 are shown to be highly unique, whereas none of the solutes behaves uniquely. Combination sets of solvent vectors and of solute vectors from the data matrix lead to models having errors within experimental error. Basic factors which might influence the solute—solvent interactions are identified by the least‐squares method of target testing. For the solvents, a number of properties, including McReynolds' constants and molecular weight, test successfully. For the solutes, carbon number and group dipole moment are representative properties which test successfully. The best combination of solvent basic factors gives errors about twice the experimental error. Combination sets composed only of McReynolds' constants do not model the data well.
Coating of TiO2 particles by chemical vapor deposition of SiO2
Authors: Powell Quint. H. , Kodas Toivo. T. , Anderson Bruce M. 
Published: May 2005

A simple CVD process for coating titanium dioxide particles to improve dispersion, pigment durability, and resistance to viscosity increases in paints is presented. The conventionally used liquid‐phase routes are complicated and expensive and often lead to porous layers, which have high oil absorption, whereas the continuous, high temperature gas phase route described here produces dense layers of silica. The Figure shows a possible mechanism for the coating process.magnified image
Study of a cobalt‐based surface modified glassy carbon electrode: Electrocatalytic oxidation of sugars and alditols
Authors: Cataldi Tommaso R. I. , Guerrieri Antonio , Casella Innocenzo G. , Desimoni Elio 
Published: May 2005

AbstractSugars and alditols undergo an electrocatalytic oxidation in alkaline solution at cobalt‐oxide‐based glassy carbon (Co/GC) electrodes. The catalytic deposit was investigated by cyclic voltammetry and scanning electron microscopy (SEM). It is pointed out that, at relatively low coverage of cobalt, two main redox processes, CoII → CoIII and CoIII → CoIV, are observed in 0.2 M NaOH. The redox behavior of the Co/GC electrode is strongly dependent on hydroxide ion concentration, and no electrocatalytic activity is observed at pH lower than 11.5. Under voltammetric conditions the modified electrode exhibits a non‐Nernstian potential/pH shift (−88 ± 3 mV per pH unit). A reasonable explanation of the E/pH behavior in alkaline solution is given and an oxidation mechanism of CoII to CoIII is proposed in terms of hydrous cobalt oxides. No detrimental effects on the electrocatalytic oxidation of polyhydric compounds are observed in the presence of high acetonitrile concentrations (up to 40%). Inspection by SEM of the cobalt‐based deposit evidenced the presence of grain‐like microcrystallites on the glassy carbon surface.
Optimum conditions for polarographic studies of mixed‐ligand complex formation
Authors: Zelić Marina 
Published: May 2005

AbstractSome characteristics of bi‐ligand systems, important for the design and performance of studies on mixed‐ligand complex formation, are given. The problem of the optimum ligand concentration is discussed using published results. In the experimental work the concentration range of the stronger complexant (at a constant level of the weaker) seems to be critical. The measurements should start under conditions where the increase in the half‐wave potential shift (with respect to the situation in the presence of only the weaker ligand) is virtually absent and finish at concentrations where it is pronounced. Small changes at the beginning reflect the ‘contribution’ of ternary species to the composite signal, whereas the big shifts at higher concentrations are mainly produced by simple species with only a minor contribution from mixed‐ligand complexes.
Mediated amperometric biosensor for nicotinic acid based on whole cells of Pseudomonas fluorescens
Authors: Takayama Katsumi , Ikeda Tokuji , Nagasawa Toru 
Published: May 2005

AbstractWhole cells of Pseudomonas fluorescens TN5 were immobilized on the surface of carbon paste electrodes containing p‐benzoquinone or its derivatives. The electrodes produced anodic currents for nicotinic acid due to the electrocatalytic action of the bacterial cells using the quinone compounds as an electron transfer mediator. The characteristics as a nicotinic acid sensor were studied of the electrode containing p‐benzoquinone. It could measure nicotinic acid in the range 5μM to 6mM with a response time of 80s and with high selectivity in the solution of pH between 4 and 10. The electrode was stable for at least two weeks when used for the measurment of nicotinic acid at the concentration below 1 mM. An alternative method of measuring nicotinic acid, which is based on the respiration reaction ofP. fluorescens, is also described.
Determination of indium in bismuth indium telluride materials by anodic stripping voltammetry. Method development
Authors: Kotrlý Stanislav , Pravda Miloslav , Šrámková Jitka , Vytŕas Karel 
Published: May 2005

AbstractDifferential‐pulse anodic‐stripping voltammetry with the use of a pen‐type hanging mercury‐drop electrode was investigated for the determination of indium as dopant in milligram samples of thermoelectric bismuth‐telluride material. After dissolving a milligram sample in dilute HN03, telluric acid present in a great excess was oxidized by H2O2in ammoniacal medium to the less interfering Te(VI). In contrast with the supporting electrolytes containing sulfuric, nitric, perchloric, and hydrochloric acid, respectively, a higher sensitivity was achieved with a citrate buffer (of pH 2.6–2.9). The calibration plot was linear up to a concentration of about 2μg In(III)per 1 mL of the measured solution; the corresponing detection limit was 5.6 ng/mL (49 nmol/L). A standard bismuth telluride material containing 2.94% w./w. In was used to compare the results of the method with applications of flame atomic absorption spectrometry, extraction spectrophotometry and scanning energy dispersive X‐ray analysis.