bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anodic stripping voltammetry at hydrodynamic mercury thin film electrodes. Part 2. Numerical simulation of stripping peaks for irreversible and quasireversible processes
Authors: Ball Jon C. , Compton Richard G. 
Published: May 2005

AbstractThe time dependent backwards implicit method is used to simulate the shape and position of the stripping peaks in DC (linear scan) anodic stripping voltammetry at mercury thin film hydrodynamic electrodes for electrochemically irreversible and quasireversible systems assuming that the electrode diffusion layer thickness is uniform, as in the case of a rotating disk electrode. The effect of the electrochemical rate constant in influencing both the peak potential and peak shape is examined and the conditions identified under which electrochemically reversible behavior is approached.
Polyion‐sensitive membrane electrodes for detecting phosphate‐rich biological polyanions
Authors: Esson Joan M. , Meyerhoff Mark E. 
Published: May 2005

AbstractAppropriately formulated polymeric membrane electrodes are shown to exhibit analytically useful nonequilibrium potentiometric responses to biologically important polyanions with high phosphate content, including polyphosphates and nucleic acids, in the μg/mL concentration range This response is dependent on the charge density, lipophilicity, and molecular weight of the polyanion species. The application of these electrodes for monitoring enzymatic activities is also demonstrated, using acid phosphatase/polyphosphate as a model system. The detection limit of this assay was found to be 0.9 ± 0.4 mU/mL with a linear range of 5–100 mU/mL. A similar electrochemical assay scheme can be utilized to monitor ribonuclease activity, using a RNA homopolymer as the substrate.
Catalytic hydrogen evolution in the presence of sulfide and cobalt ions. A study by cathodic stripping voltammetry on the hanging mercury drop electrode
Authors: Bǎnicǎ Florinel Gabriel , Spǎtaru Nicolae , Spǎtaru Tanţa 
Published: May 2005

AbstractTraces of sulfide ion produce a cathodic peak on the HMDE at about −1.50 V (vs. SCE) after preconcentration at −0.5 V in the borax buffer containing 0.01 mM CoII. This peak is due to the catalytic hydrogen evolution, as demonstrated by the influence of the buffer concentration, the effect of water substitution by deuterium oxide and by the formation of hydrogen bubbles on the electrode. The effect of sulfide ion concentration, deposition time and deposition potential demonstrate that a positively charged cobalt complex is adsorptively accumulated during the deposition step. The reduction of CoII in this species produces a catalytically active compound which is involved in the reduction of the hydrogen ion according to the proposed mechanism. The potential analytical applications of this process for the determination of the sulfide ion have been assessed. The peak current is directly proportional to the concentration of the sulfide ion enabling the application of the standard addition method. The detection limit (using either normal or derivative LSV) is about 1 nM for 10 min accumulation time. The accuracy and reproducibility are fairly good and some of the common interferences in CSV of sulfide ion are removed or at least diminished.
Comparison of metalloporphyrins interacting with DNA
Authors: Qu Feng , Li Nan‐Qiang 
Published: May 2005

AbstractA series of metalloporphyrins (CuTMpyP, CuTMAP. CuTPPS, NiTMpyP, ZnTMpyP and CdTMpyP) reacting with DNA were compared. The interaction of metalloporphyrin with DNA shows different binding modes and electrochemical behavior when either the metal ion or porphyrin ligand is different. Due to electrostatical repulsion interaction between the anionic substitute group and a phosphate group on DNA molecular backbone, it is difficult for the anionic porphyrin to interact with DNA. The ability of cationic porphyrins to react with DNA depends on the size of the substitute group and the metal ion in the porphyrin plane center. Metalloporphyrin with or without axial ligand, which depends on the metal ion, results in outside binding or intercalating modes, and shows different interaction capability with DNA. The conditional binding constants of NiTMpyP, CuTMpyP and CuTMAP, which mainly show intercalating mode to DNA, were evaluated.
A new cerium(IV) vanadate‐based solid membrane electrode for bismuth(III)
Authors: Jain Ajay K. , Gupta Vinod K. , Singh Lok P. , Khurana Upendra 
Published: May 2005

AbstractA 20% (w./w.) polystyrene‐based heterogeneous membrane of inorganic ion‐exchanger, cerium(IV) vanadate, has been prepared and used as a bismuth(III) selective electrode. The electrode gives linear potential response in the concentration range 8.0 × 10−5‐1.0 × 10−1 mol L−1 with a slope of 19.2 mV per decade of concentration and a fast response time of 50s. The electrode functions well in the pH range 2.0–4.0, in partially nonaqueous media up to 25% (v./v.) alcoholic content and was used over a period of 4 months without any significant drift in potentials. It exhibits selectivity for Bi3+ over a large number of metal ions and can be used as an indicator electrode to determine Bi3+ by potentiometric titration with EDTA.
Fabrication of a multilayer film electrode containing 12‐tungstosilicic acid and its electrocatalytic reduction for nitrite
Authors: Sun Changqing , Zhang Jidong 
Published: May 2005

AbstractA novel multilayer film electrode was designed based on the interaction between molecules of 12‐tungstosilicic acid and poly(4‐vinylpyridine) in organic phase. The electrochemical behavior of the modified electrode is characterized. The modified electrode exhibits an excellent and stable electrocatalytic response for the reduction of nitrite.
Mesoporous TiO2 films: New catalytic electrode fabricating amperometric biosensors based on oxidases
Authors: Cosnier Serge , Gondran Chantal , Senillou Anne , Grätzel Michael , Vlachopoulos Nicholas 
Published: May 2005

AbstractA novel catalytic material (mesoporous TiO2 films) for the cathodic detection of hydrogen peroxide in air‐saturated aqueous solution is described. The immobilization of glucose oxidase (GOD) as enzyme model onto the TiO2 electrode provides an efficient biosensor for the amperometric detection of glucose at −0.15 V (vs. SCE). GOD molecules were immobilized in an inorganic laponite gel and cross‐linked by glutaraldehyde. The highest sensitivity and detection limit were 3.33 mAM−1 cm−2 and 15 μM, respectively. In addition different procedures of enzyme immobilization including cross‐linking with glutaraldehyde and physical entrapment in a functionalized polypyrrole film have been compared.
A Murine Model of Acute Liver Injury Induced by Human Monoclonal Autoantibody *
Authors: Yamauchi Katsumi , Yamaguchi Naoko , Furukawa Takaji , Takatsu Kazuko , Nakanishi Toshimi , Ishida Kohji , Komatsu Tatsuji , Tokushige Katsutoshi , Nagahara Hikaru , Hashimoto Etsuko , Shiratori Keiko 
Published: May 2005

Abstract

We have previously reported an immunoglobulin (Ig) M autoantibody to hepatocyte-related 190-kd molecules in patients with type 1 autoimmune hepatitis (AIH). This molecule was first isolated by hepatocyte-specific human monoclonal antibody (MoAb). To elucidate the role of this IgM autoantibody in hepatocyte injury, we examined the reactivity of this MoAb to murine hepatocytes and then questioned whether acute hepatic injury could be induced in mice via injection of this MoAb. The reactivity of MoAb was examined via both FACS analysis using murine hepatocytes and immunostaining of liver tissues. We then identified the murine hepatocyte membrane molecule recognized by this MoAb. The role of this MoAb in the immunopathogenesis of AIH was assessed by testing whether its injection into mice could increase serum aminotransferase levels as well as cause changes in liver histology. The present results demonstrate that this MoAb cross-reacted with murine hepatocytes and recognized a 190-kd molecule on the murine hepatocyte membrane just as in human hepatocytes. One hour after the injection of MoAb, the deposition of both IgM and complement component 3 was found in liver tissues. At 8 hours after the injection, serum aminotransferase levels were significantly increased in MoAb-injected mice compared with controls. Histological study revealed massive hepatocyte necrosis in MoAb-injected mice.
In conclusion
, human MoAb recognized a 190-kd molecule of both human and murine hepatocytes, and the injection of this MoAb to mice resulted in acute liver injury, indicating that this type of autoantibody may play an important role in the immunopathogenesis of AIH. (Hepatology 2005.)
In vivo intrahippocampal microinfusion of carbachol and bicuculline induces theta‐like oscillations in the septally deafferented hippocampus
Authors: Colom Luis V. , Nassif‐Caudarella Siham , Dickson Clayton T. , Smythe James W. , Bland Brian H. 
Published: May 2005

AbstractIn their laboratory the authors have previously demonstrated that hippocampal slices could be induced to generate trains of “theta‐like” oscillations by whole‐bath perfusions of carbachol. Until recently, it has not been possible to generate similar activity in the septally deafferented hippocampus of an otherwise intact brain by microinfusions of carbachol. This study presents a full report of the first demonstration of a theta‐like oscillation in the in vivo, septally deafferented hippocampal formation. Rats were anesthetized with urethane and implanted with microinfusion cannulae in the region of the medial septum/vertical limb of the diagonal band of Broca (MS/vDBB) and at single or multiple sites in the stratum moleculare of the fascia dentata. The MS/vDBB was microinfused with procaine hydrochloride to produce a reversible suppression lasting for approximately 20 minutes. Intrahippocampal microinfusions of carbachol or bicuculline alone (in the postprocaine condition of the MS/vDBB) failed to produce any theta‐like oscillations. The combination of carbachol and bicuculline produced trains of theta‐like oscillations during suppression of the MS/vDBB very similar to those seen in the slice preparations. The oscillations were blocked by intravenous administration of atropine sulfate, and they had the same depth profile as that of theta. Theta‐on cells were shown to discharge in rhythmic bursts in synchrony with the oscillations. Thus, it would appear that the essential nature of the medial septal input to the hippocampal formation, for the generation of theta field activity in the intact brain, consists of a critical balance between cholinergic and GABAergic circuitry.
Isoproterenol increases the phosphorylation of the synapsins and increases synaptic transmission in dentate gyrus, but not in area CA1, of the hippocampus
Authors: Parfitt Karen D. , Van Doze A. , Madison Daniel V. , Browning Michael D. 
Published: May 2005

AbstractPrevious studies have shown that either norepinephrine (NE) or isoproterenol (ISO) enhances the slope of the field excitatory postsynaptic potential (EPSP) in the dentate gyrus of the rat hippocampal formation. In contrast, NE and ISO cause no increase in excitatory transmission in area CA1 of the hippocampus. The molecular mechanism underlying this brain region‐specific increase in synaptic transmission is not known. The phosphorylation of synapsin I and synapsin II, two homologous presynaptic vesicle‐associated proteins, is thought to promote neurotransmitter release. The authors have observed previously NE‐ and ISO‐enhanced phosphorylation of synapsins I and II in the dentate gyrus. The purpose of this study was to determine whether ISO‐stimulated phosphorylation also occurs in the CA1, where ISO has no effect on excitatory neurotransmission. These studies were correlated with electrophysiological studies in in vitro hippocampal slices. Superfusion of slices with ISO resulted in an increase in EPSP slope in the dentate but not in area CA1. The enhanced dentate EPSP returned to baseline levels within 30 minutes of washout of the drug. Isoproterenol produced corresponding increases in the phosphorylation of the synapsins in dentate slices but had no effect on these proteins in CA1 slices. Moreover, in dentate slices exposed to a 30‐minute wash following incubation with ISO, phosphorylation of the synapsins returned to control levels. This close temporal and brain regional correlation between ISO stimulation of both synapsin phosphorylation and synaptic transmission suggests that the synapsin proteins may play a role in the synaptic potentiation produced by ISO in the dentate.
Preserved configural learning and spatial learning impairment in rats with hippocampal damage
Authors: Gallagher Michela , Holland Peter C. 
Published: May 2005

AbstractThis study was undertaken to compare the effect of hippocampal neurotoxic lesions in rats on two behavioral tasks, one a test of spatial learning, and the other an operant discrimination task that is acquired by forming nonspatial configural associations. Lesions of the hippocampus were made with microinjections of ibotenic acid. After postoperative recovery, rats were trained initially to locate a camouflaged escape platform in a water maze using distal spatial cues. Rats also were trained in the maze apparatus with a visible escape platform under conditions in which spatial information was made irrelevant to performance, i. e., cue learning. In an operant task, the same rats were then trained on a discrimination that included simultaneous feature positive and feature negative components (trial types XA+, A−, XB−, B+). After completion of this nonspatial configural learning task, rats received additional training in the water maze using a new platform location for spatial learning. To the extent that proficient performance in both the maze and operant tasks depends on a common function of the hippocampus, i. e., configural learning, the expectation was that hippocampal lesions would prove equally detrimental to performance in both tasks. Contrary to this expectation, lesioned rats were severely impaired in spatial learning but readily acquired the operant discrimination, even exhibiting some evidence of enhanced performance on this nonspatial configural learning task. Performance of the lesioned rats during cue training in the water maze was also enhanced relative to the control group. These results demonstrate that a spatial learning deficit in rats with hippocampal damage does not necessarily occur in the setting of a general configural learning impairment, as originally suggested by Sutherland and Rudy (1989, Psychobiology 17:129–144).
Tracing of axonal connections by rhodamine‐dextran‐amine in the rat hippocampal‐entorhinal cortex slice preparation
Authors: Boulton Carolyn L. , v. Haebler Dorothea , Heinemann Uwe 
Published: May 2005

AbstractIn order to demonstrate axonal connections preserved in rat temporal cortex slices the authors used rhodamine‐dextran‐amine as a tracer. The slices contained the neocortical areas Te2 and Te3, the medial and lateral entorhinal cortices (MEC and LEC), the subicular regions, and the dentate gyrus and hippocampus proper. Rhodamine‐dextran‐amine crystals were placed by microinjection into a given area. Following this local lesioning the dye was permitted to diffuse and migrate intraaxonally in antero‐and retrograde directions for about 8 hours. The slices were then formaldehyde‐fixed and analyzed by fluorescence microscopy. Most of the known connections within and between the entorhinal cortex and the hippocampus and denatate gyrus were preserved in the slice preparation, provided that the slices were cut with a near horizontal orientation corresponding to plates 99–108 in Paxinos and Watson (1986). Only the lateral perforant path between the LEC and the hippocampus could not be followed to its full extent. The authors conclude that most aspects of the intrinsic synaptic organization of the temporal lobe can be reliably studied in hippocampal‐entorhinal cortex slice preparations.
Postnatal development of mossy cells in the human dentate gyrus: A light microscopic Golgi study
Authors: Seress László , Mrzljak Ladislav 
Published: May 2005

AbstractMossy cells in the human dentate gyrus of adults and children of different ages were impregnated using the rapid‐Golgi method. In every case the cause of death was verified by autopsy and the brains were used when neither the history of the patient nor autopsy revealed brainrelated disease.Mossy cells in the human share common light microscopic features with the same cell type in rats and monkeys. Their most characteristic feature is the extremely large and complex excrescences on their proximal dendrites. Distal dendrites display pedunculate spines. Mossy cells have a few somal spines. The axon of mossy cells originates from the cell body and gives rise to several collaterals in the hilar region. The axons could be followed for several hundred microns, but in only one case did an axon collateral enter the granule cell layer of the adult dentate gyrus.In the newborn child, mossy cells display immature somal and dendritic features. The soma frequently bear spines. The dendrites are varicose and terminate in presumed growth cones. Both proximal and distal portions of the dendrites bear a few pedunculate spines and longirregular filopodia. A few small excrescences are present on the proximal dendrites. The first large, complex excrescences on the proximal dendrites of mossy cells appeared in the 7‐month‐old child. Both somata and dendrites dispaly adult‐like characteristics in mossy cells from a 5‐year‐old child. However, not all mossy cells are alike and some dendrites still display long filopodia. The axons of immature mossy cells were similar to adults.The present results indicate that connections between granule cells and hilar mossy cells of the human dentate gyrus develop through an extended postnatal period of time that may last until the fifth year.
Intact verbal and nonverbal short‐term memory following damage to the human hippocampus
Authors: Cave Carolyn Backer , Squire Larry R. 
Published: May 2005

AbstractShort‐term memory was assessed in two groups of amnesic patients. Six patients had confirmed or suspected damage to the hippocampal formation, and six patients had diencephalic damage as a result of alcoholic Korsakoff's syndrome. Verbal short‐term memory was evaluated with seven separate administrations of the standard digit span test in order to obtain a precise measure of short‐term memory. Nonverbal short‐term memory was evaluated with four tests that assessed apprehension, retention, and the ability to manipulate nonverbal material—all within the span of immediate memory. One of these four tests assessed short‐term memory for spatial location. Patients with damage to the hippocampal formation had a digit span equivalent to that of control subjects and also performed normally on the four tests of nonverbal short‐term memory. The patients with Korsakoff's syndrome had a marginally low digit span and performed poorly on three of the four nonverbal tasks, a finding consistent with the deficits in attention and visuospatial processing previously described for this patient group. These deficits are likely due to the frontal lobe atrophy typically associated with Korsakoff's syndrome, rather than to diencephalic damage. The results support the view that short‐term (immediate) memory, including short‐term spatial memory, is independent of the hippocampus.
The importance of comparative studies and ecological validity for understanding hippocampal structure and cognitive function
Authors: Bingman Verner P. 
Published: May 2005

AbstractBuilding from the premise that hippocampal cognitive function has been molded by natural selection under natural environmental conditions, it is argued that traditional laboratory studies likely do not reveal the richness and complexity of hippocampal function. Research on the role of the hippocampal formation in the navigational behavior of homing pigeons is offerred as an example to illustrate the advantages of using an ecological approach to understand hippocampal function. It is further proposed that dissimilarities in hippocampal anatomy, physiology, and neurochemistry found between species reflect species differences in the range of functions served by the hippocampal formation, as well as possibly the molecular and cellular mechanisms that support such functions. These differences notwithstanding, it is suggested that, from an evolutionary perspective, the primary function of the hippocampal formation is a role in some aspect of spatial cognition. Dissimilarities in hippocampal structure and function among extant species are viewed as resulting from differences in evolutionary selective pressure and evolutionary history.
The mechanism of cerebral hypoxic‐ischemic damage
Authors: Schurr Avital , Rigor Benjamin M. 
Published: May 2005

AbstractThe four most prominent hypotheses on the cellular processes leading to hypoxic‐ischemic neuronal damage or death are (1) the lactacidosis hypothesis, (2) the calcium overload hypothesis, (3) the excitotoxic hypothesis, and (4) the oxygen‐free radical hypothesis. The authors comment on the evidence in favor of and against each in an attempt to select the one hypothesis that best explains the mechanism of cerebral hypoxic‐ischemic damage while withstanding the scrutiny of scientific testing. A major part of this inquiry is derived from in vitro studies that are suited to mechanistic exploration. They conclude that the calcium overload hypothesis is the best qualified in this respect. It is important to note, however, that some of the other hypothetical mechanisms may play a secondary role in exacerbating neuronal damage by accelerating calcium influx and overload.