bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cholinergic modulation of Pavlovian fear conditioning: Effects of intrahippocampal scopolamine infusion
Authors: Gale Greg D. , Anagnostaras Stephan G. , Fanselow Michael S. 
Published: November 2004

AbstractCholinergic neurotransmission has been implicated in the acquisition of a variety of tasks, including Pavlovian fear conditioning. To more precisely define the role of cholinergic modulation in this process, the effect of site‐specific cholinergic antagonism was assessed. Male Long‐Evans rats were implanted with chronic, bilateral cannulae aimed at the dorsal hippocampus. Infusions of scopolamine hydrobromide (50 μg bilaterally) or phosphate‐buffered saline (PBS) were made immediately prior to a signaled Pavlovian fear conditioning procedure. On consecutive days following training, all rats were given independent tests assessing freezing to both the training context and the tone conditional stimulus (CS). Relative to PBS infused controls, rats that received intrahippocampal infusions of scopolamine showed a significant attenuation of contextual freezing but comparable levels of freezing to the tone CS. Neither shock sensitivity nor general activity levels differed between rats infused with scopolamine or PBS. These findings suggest that fear conditioning to context, but not discrete CS, requires intact cholinergic neurotransmission in the hippocampus. Hippocampus 2001;11:371–376. © 2001 Wiley‐Liss, Inc.
Increased extracellular release of hippocampal NE is associated with tetanization of the medial perforant pathway in the freely moving adult male rat
Authors: Bronzino Joseph D. , Kehoe Priscilla , Mallinson Kathy , Fortin Dale A. 
Published: November 2004

AbstractThe induction of long‐term potentiation (LTP) within the dentate gyrus of the hippocampal formation is modulated by many afferent influences from a number of subcortical structures known to be intimately involved in hippocampal‐dependent learning and memory. It has been demonstrated in slice and anesthetized preparations that norepinephrine (NE) is one of these major neuromodulators involved in the induction of LTP. However, the majority of these studies have not been conducted in the freely moving animal. Recently, we developed surgical procedures and instrumentation techniques to simultaneously record electrophysiological and neurochemical data from the hippocampal formation. The present study uses these techniques to examine the underlying neurochemical changes in the hippocampus associated with the induction of hippocampal dentate LTP in the freely moving adult rat. These findings establish baseline levels of NE that can be used to evaluate the impact of various tetanization paradigms as well as the effect of a variety of insults on hippocampal plasticity. Hippocampus 2001;11:423–429. © 2001 Wiley‐Liss, Inc.
Alterations of hippocampal GABAergic system contribute to development of spontaneous recurrent seizures in the rat lithium‐pilocarpine model of temporal lobe epilepsy
Authors: André Véronique , Marescaux Christian , Nehlig Astrid , Fritschy Jean Marc 
Published: November 2004

AbstractReorganization of excitatory and inhibitory circuits in the hippocampal formation following seizure‐induced neuronal loss has been proposed to underlie the development of chronic seizures in temporal lobe epilepsy (TLE). Here, we investigated whether specific morphological alterations of the GABAergic system can be related to the onset of spontaneous recurrent seizures (SRS) in the rat lithium‐pilocarpine model of TLE. Immunohistochemical staining for markers of interneurons and their projections, including parvalbumin (PV), calretinin (CR), calbindin (CB), glutamic acid decarboxylase (GAD), and type 1 GABA transporter (GAT1), was performed in brain sections of rats treated with lithium‐pilocarpine and sacrificed after 24 h, during the silent phase (6 and 12 days), or after the onset of SRS (10–18 days after treatment). Semiquantitative analysis revealed a selective loss of interneurons in the stratum oriens of CA1, associated with a reduction of GAT1 staining in the stratum radiatum and stratum oriens. In contrast, interneurons in CA3 were largely preserved, although GAT1 staining was also reduced. These changes occurred within 6 days after treatment and were therefore insufficient to cause SRS. In the dentate gyrus, extensive cell loss occurred in the hilus. The pericellular innervation of granule cells by PV‐positive axons was markedly reduced, although the loss of PV‐interneurons was only partial. Most strikingly, the density of GABAergic axons, positive for both GAD and GAT1, was dramatically increased in the inner molecular layer. This change emerged during the silent period, but was most marked in animals with SRS. Finally, supernumerary CB‐positive neurons were detected in the hilus, selectively in rats with SRS. These findings suggest that alterations of GABAergic circuits occur early after lithium‐pilocarpine‐induced status epilepticus and contribute to epileptogenesis. In particular, the reorganization of GABAergic axons in the dentate gyrus might contribute to synchronize hyperexcitability induced by the interneuron loss during the silent period, leading to the onset of chronic seizures. Hippocampus 2001;11:452–468. © 2001 Wiley‐Liss, Inc.
Acute stress and dexamethasone rapidly increase hippocampal somatostatin synthesis and release from the dentate gyrus hilus
Authors: Arancibia Sandor , Payet Olivier , Givalois Laurent , Tapia‐Arancibia Lucia 
Published: November 2004

AbstractSomatostatin is a neuropeptide whose facilitatory action in the generation of long‐term potentiation (LTP) in the hippocampal dentate gyrus has been associated with memory processes. Since stress and memory seem to share some neural pathways, we studied somatostatin release from dentate gyrus hilar cells of the hippocampus in unanesthetized free‐moving rats subjected to stress or dexamethasone treatments. In parallel, the number of dentate gyrus hilar cells expressing somatostatin mRNA was quantified by nonradioactive in situ hybridization in these two experimental conditions.Rats were stereotaxically implanted with a push‐pull cannula in the dentate gyrus hilar region. Animals were perfused 1 week later in basal or stress (30 min immobilization stress) conditions. The other group was intraperitoneally injected with the synthetic glucocorticoid dexamethasone (3 mg/kg b.w.). Samples were collected every 15 min for somatostatin radioimmunoassay. In parallel, in other groups of animals undergoing the same treatments, brains were removed for in situ hybridization studies with an oligonucleotide labeled with digoxigenin that recognizes somatostatin‐14.The results showed that stress induced a significant increase in somatostatin release from dentate gyrus hilar cells 30–45 min after immobilization stress application. Dexamethasone‐injected animals exhibited a similar response 45 min after drug administration. In situ hybridization analysis revealed that the two treatments significantly increased the number of cells expressing somatostatin mRNA in the hilar region.In conclusion, somatostatin interneurons of the hippocampal hilar region appear to be a novel stress stimulus target. Their rapid reactivity, expressed as modifications of both somatostatin release and number of cells expressing somatostatin mRNA, provides an interesting model of neuronal plasticity. Hippocampus 2001;11:469–477. © 2001 Wiley‐Liss, Inc.
NMDA receptor regulation of memory and behavior in humans
Authors: Newcomer John W. , Krystal John H. 
Published: November 2004

AbstractN‐methyl‐D‐aspartate (NMDA) receptor hypofunction is associated with a range of effects on cognition and behavior in whole animal and human studies. NMDA receptor hypofunction within the brain, which can be induced experimentally in vivo using NMDA receptor antagonist drugs, produces adverse effects on memory function. The results suggest that NMDA receptor hypofunction can preferentially affect neural mechanisms regulating the efficiency of encoding and consolidation into longer‐term storage. More pronounced NMDA receptor hypofunction can produce a clinical syndrome that includes core features of psychosis, as well as dissociation. Finally, sustained and severe underexcitation of NMDA receptors in the adult brain is associated with a neurotoxic process with well‐characterized neuropathological features. Progressive increases in severity of NMDA receptor hypofunction within the brain can produce a range of effects on brain function, involving local and distributed circuitry, which may underlie the observed changes in behavior. As the brain ages, the NMDA receptor system becomes progressively hypofunctional, potentially contributing to further age‐related decreases in memory and learning performance. Pharmacological and genomic methods for preventing NMDA receptor hypofunction, or for preventing the upstream or downstream consequences modeled by treatment with NMDA antagonists, may be applicable to the prevention and treatment of memory and behavioral dysfunction in a variety of neuropsychiatric disease conditions. Hippocampus 2001;11:529–542. © 2001 Wiley‐Liss, Inc.
The sensitivity and specificity of FDG PET in distinguishing recurrent brain tumor from radionecrosis in patients treated with stereotactic radiosurgery
Authors: Chao Samuel T. , Suh John H. , Raja Shanker , Lee Shih‐Yuan , Barnett Gene 
Published: November 2004

AbstractRadiation necrosis and recurrent brain tumor have similar symptoms and are indistinguishable on both magnetic resonance imaging (MRI) and computed tomograph scans. 18F‐fluorodeoxyglucose (FDG) positron emission tomography (PET) has been proposed as a diagnostic alternative, particularly when co‐registered with MRI. We studied 47 patients with brain tumors treated with stereotactic radiosurgery and followed with FDG PET. For all tumor types, the sensitivity of FDG PET for diagnosing tumor was 75% and the specificity was 81%. For brain metastasis without MRI co‐registration, FDG PET had a sensitivity of 65% and a specificity of 80%. For brain metastasis with MRI co‐registration, FDG PET had a sensitivity of 86% and specificity of 80%. MRI co‐registration appears to improve the sensitivity of FDG PET, making it a useful modality to distinguish between radiation necrosis and recurrent brain metastasis. © 2001 Wiley‐Liss, Inc.
Ionizing radiation induces CD20 surface expression on human B cells
Authors: Kunala Subrahmanyam , Macklis Roger M. 
Published: November 2004

AbstractThe CD20 surface antigen is expressed on the great majority of B‐cell lymphoma cases. The expression of this antigen ranges from moderate to bright, and it is neither internalized nor shed. These characteristics make CD20 a common target for antibody directed lymphoma therapy. The development of strategies to significantly increase CD20 expression on lymphoma cells is therefore of great interest as a means of increasing specific targeting and cell kill in antibody therapy and radio‐immunotherapy. We present here data demonstrating that relatively low doses of external beam radiotherapy are capable of significant and consistent increases in CD20 surface expression in vitro. The effect is dose related up to approximately 10 Gy and is maximal in the first day after radiotherapy. We believe that these data may suggest a potent way to combine a short pretreatment course of external beam radiotherapy with a subsequent course of immunotherapy using either an unlabeled antibody or a radio‐immunotoxin. © 2001 Wiley‐Liss, Inc.
Discovery in toxicology: Mediation by gene expression array technology
Authors: Hamadeh Hisham K. , Bushel Pierre , Paules Richard , Afshari Cynthia A. 
Published: November 2004

AbstractToxicogenomics is a term that represents the merging of toxicology with novel genomics techniques. Data generated in the new‐age era of toxicology is relatively complex, requires new bioinformatics tools for adequate interpretation, and allows for the rapid generation of testable hypotheses. Hazard identification and risk assessment processes will advance from the use of genomics techniques, which will lead to greater understanding of mechanism(s) of action of toxicants, development of novel biomarkers of exposure and effect, and better identification of sensitive subpopulations. © 2001 John Wiley & Sons, Inc. *This article is a US Government work and, as such, is in the public domain in the United States of America.
J Biochem Mol Toxicol 15:231–242, 2001
Effects of the circadian mutation ‘tau’ on the Harderian glands of Syrian hamsters
Authors: Coto‐Montes Ana , Tomás‐Zapico Cristina , Rodríguez‐Colunga María Josefa , Tolivia‐Cadrecha Delio , Martínez‐Fraga Jorge , Hardeland Rüdiger , Tolivia Delio 
Published: November 2004

AbstractThe Syrian hamster Harderian gland (HG) is an organ continually exposed to oxidative stress caused by high concentrations of porphyric metabolites. According to previous studies, melatonin, which is rhythmically secreted by the pineal gland and tonically produced by the HG, antagonizes the oxidative damage. HGs exhibit a strong gender‐dependent correlation between porphyrins, melatonin, and histological appearance. In HGs of both sexes, we have investigated effects of a single gene defect in the circadian clock system (tau mutation) causing a shortened free‐running period and an advanced maximum of circulating melatonin. Comparisons were made with wild‐type animals, one group of which received daily pharmacological injections of melatonin in late photophase. Changes were observed in histological characteristics, porphyrin content, antioxidant enzyme activities, and damage of proteins and lipids. HGs of tau hamsters showed morphological changes which can be partially interpreted in terms of increased damage. Additionally, tau females exhibited a many‐fold augmentation in the percentage of so‐called type II cells, which are otherwise typical for the male glands. In tau hamsters of both sexes, major antioxidative enzyme activities (superoxide dismutase, glutathione reductase, and catalase) were markedly enhanced, a presumably compensatory response to increased oxidative stress. Higher oxidative damage in tau HGs was directly demonstrable by a many‐fold increase in protein carbonyl. Rises in antioxidative enzymes were also observed upon injections of melatonin; this was, however, not accompanied by changes in protein carbonyl, so that enzyme inductions by the hormone should be understood as protective actions. Our data are not only in accordance with findings on protective effects by melatonin, but also with our earlier observation made in Drosophila that perturbations in the circadian system lead to increased oxidative stress. J. Cell. Biochem. 83: 426–434, 2001. © 2001 Wiley‐Liss, Inc.
The MPSim‐Dock hierarchical docking algorithm: Application to the eight trypsin inhibitor cocrystals
Authors: Cho Art E. , Wendel John A. , Vaidehi Nagarajan , Kekenes–Huskey Peter M. , Floriano Wely B. , Maiti Prabal K. , Goddard William A. 
Published: November 2004

AbstractTo help improve the accuracy of protein–ligand docking as a useful tool for drug discovery, we developed MPSim‐Dock, which ensures a comprehensive sampling of diverse families of ligand conformations in the binding region followed by an enrichment of the good energy scoring families so that the energy scores of the sampled conformations can be reliably used to select the best conformation of the ligand. This combines elements of DOCK4.0 with molecular dynamics (MD) methods available in the software, MPSim. We test here the efficacy of MPSim‐Dock to predict the 64 protein–ligand combinations formed by starting with eight trypsin cocrystals, and crossdocking the other seven ligands to each protein conformation. We consider this as a model for how well the method would work for one given target protein structure. Using as a criterion that the structures within 2 kcal/mol of the top scoring include a conformation within a coordinate root mean square (CRMS) of 1 Å of the crystal structure, we find that 100% of the 64 cases are predicted correctly. This indicates that MPSim‐Dock can be used reliably to identify strongly binding ligands, making it useful for virtual ligand screening. © 2004 Wiley Periodicals, Inc. J Comput Chem 26: 48–71, 2005
Fine adjustment of the coupling length of a Ti‐diffused LiNbO3 directional coupler with a groove structure
Authors: Liu Ju‐Feng , Lin Yih‐Bin , Wang Way‐Seen 
Published: November 2004

AbstractTwo kinds of groove structure for shortening and broadening the coupling lengths of Ti:diffused LiNbO3 directional couplers are presented. The coupling lengths as functions of the depth, width, and spacing of the grooves were numerically calculated. The results show that the maximum shortening of the coupling length is up to 43%, and the maximum broadening is even larger, depending on the groove depth. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 301–303, 2001.
Mixing frequency achievement with a photoinduced load in silicon substrate
Authors: Ahouassa P. , Boussey J. , Bouthinon M. , Vilcot A. 
Published: November 2004

AbstractA metallic microstrip line deposited on silicon, illuminated at its end while its entry is being connected to an ultra‐high‐frequency generator, presents a photoinduced load at its extremity. By performing a mixing frequency experiment, it has been proved that this load actually behaves as a nonlinear element. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 309–312, 2001.
A new compact dual‐band dual‐polarized microstrip antenna
Authors: Paulson Manju , Kundukulam Sona O. , Aanandan C. K. , Mohanan P. 
Published: November 2004

AbstractA new compact dual‐band, dual‐polarized microstrip antenna is presented. This antenna resonates at two frequencies with different polarizations: a linearly polarized one for terrestrial communication, and a circularly polarized one for satellite mobile communication. This antenna also provides an area reduction of 70% compared to a standard rectangular patch antenna. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 315–317, 2001.
A method‐of‐moments‐based algorithm to synthesize a conformal onboard array antenna
Authors: Obelleiro F. , Landesa L. , Taboada J. M. 
Published: November 2004

AbstractThe design of low‐sidelobe radiation patterns for array antennas mounted over aircrafts, ships, or any other complex platform is performed here. Both the electromagnetic coupling with the platform and the mutual coupling between the array elements are considered, and their effects are introduced in a novel synthesis algorithm. This is done by using a method‐of‐moments‐based algorithm for three‐dimensional scatters combined with an optimization procedure. The proposed method leads to a set of excitation coefficients that optimize the conformal array antenna over the vehicular platform. Some results are presented to demonstrate that high‐performance radiation patterns can be synthesized. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 324–328, 2001.
Propagation characteristics of Schottky‐contact slow‐wave microstrip line
Authors: Verma A. K. , Nasimuddin  
Published: November 2004

AbstractThe present paper computes the normalized phase constant, dielectric loss, and conductor loss of the voltage‐controlled Schottky‐contact microstrip line using the variational method based on the single‐layer reduction (SLR) formulation. Results computed by the SLR formulation show very good agreement with the experimental results, both in the normalized phase constant and total losses with 2.0% and 0.01 dB/mm, respectively. The present formulation can also handle a greater number of dielectric layers. The model is suitable for the CAD of Schottky‐contact microstrip structures. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 341–344, 2001.
Community Leadership Is the Key to Meeting the Y2K Challenge
Authors: Davis Steven C. 
Published: November 2004

AbstractCommunities need to respond quickly to the unique aspects and broad scope of the year 2000 problem and its risks. The public is looking to government for information and assistance as it grapples with the personal issues Y2K presents. But it will take broad‐based and innovative approaches to deal with the host of Y2K issues.
Synthesis and characterization of new soluble poly(amide‐imide)s derived from 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]hexafluoropropane
Authors: Liaw Der‐Jang , Hsu Pei‐Nan , Chen Wen‐Hsiang , Liaw Been‐Yang 
Published: November 2004

AbstractA series of new soluble poly(amide‐imide)s were prepared from the diimide‐dicarboxylic acid 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]hexafluoropropane with various diamines by direct polycondensation in N‐methyl‐2‐pyrrolidinone containing CaCl2 with triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 0.52–0.86 dL · g−1. The poly(amide‐imide)s showed an amorphous nature and were readily soluble in various solvents, such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, pyridine, and cyclohexanone. Tough and flexible films were obtained through casting from DMAc solutions. These polymer films had tensile strengths of 71–107 MPa and a tensile modulus range of 1.6–2.7 GPa. The glass‐transition temperatures of the polymers were determined by a differential scanning calorimetry method, and they ranged from 242 to 279 °C. These polymers were fairly stable up to a temperature around or above 400 °C, and they lost 10% of their weight from 480 to 536 °C and 486 to 537 °C in nitrogen and air, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3498–3504, 2001
Quantum hysteresis loops in coupled two‐dimensional microscopic systems: Loop area and energy dissipation
Authors: Mondal Chandan Kumar , Bhattacharyya S. P. 
Published: November 2004

AbstractA recipe is proposed for calculating the area enclosed by hysteresis‐like loops in a periodically forced bistable microscopic system at zero temperature by using the time‐dependent Hellmann–Feynman theorem and the Fourier grid Hamiltonian method for solving the time‐dependent Schrödinger equation. The method is applied to the dynamics of a particle moving in a two‐dimensional system involving coupled Morse and symmetric double‐well potentials and interacting with an external time periodic field. The dependence of the computed loop area on the coupling strength and characteristics of the external field are analyzed, throwing light on energy transfer to the mode not directly coupled to the external field. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 11–21, 2001
Thomas–Fermi approximation for the quasi‐two‐dimensional electron gas
Authors: Moreno M. , Méndez‐Moreno R. M. 
Published: November 2004

AbstractTo take into account static correlation effects in the quasi‐two‐dimensional electron gas a screened Coulombic interaction between particles is studied. The Thomas–Fermi approximation is used and the potential screening appears as a function of the Wigner–Seitz density parameter rs and the effective width t of the system. With the self‐consistent field theory applied to the modified deformable jellium, the ground‐state energy per particle and the conditions for electron localization are obtained in terms of the interparticle distance and the screening parameter μ. A critical minimum characteristic width tc is obtained; below tc no long‐range order is obtained. For larger widths a stable localized state is predicted at finite densities. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 82: 269–276, 2001