bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of progesterone derivatives, dihydroprogesterone and tetrahydroprogesterone, on the subependymal layer of the adult rat
Authors: Giachino Claudio , Galbiati Mariarita , Fasolo Aldo , Peretto Paolo , Melcangi Roberto C. 
Published: February 2004

AbstractIndirect evidence suggests that in the subependymal layer (SEL) steroid hormones could be partially involved in the modulation of neurogenesis, but little or nothing is known about a direct effect of these molecules on this cellular system. The possible effect of progesterone (P) and/or its neuroactive metabolites, dihydroprogesterone (DHP) and tetrahydroprogesterone (THP), on the two cellular components of the SEL (i.e., proliferating/migrating neuroblasts and protoplasmic astrocytes) has been analyzed in adult male rat. P, DHP, and THP were administered by intraventricular injections and after 2 days the SEL was analyzed by immunohistochemistry by using anti‐glial fibrillary acidic protein (GFAP) and anti‐vimentin antibodies, to label the glial compartment, anti‐polysialylated form of the neural cell adhesion molecule (PSA‐NCAM), anti‐Stathmin, and anti‐β III Tubulin antibodies to label the migrating neuroblasts. Furthermore, the newly formed cells were identified by using intraventricular injections of 5‐bromo‐2′‐deoxyuridine (BrdU) detected immunohistochemically. Our results demonstrate that DHP and THP treatments drastically decrease the number of BrdU‐labeled cells within the SEL. THP, DHP, and to a lesser extent P, administrations also induce molecular and structural modifications of the SEL glial compartment. On the whole, the present results indicate that neuroactive derivatives of P (i.e., DHP and THP) exert direct effects on adult neurogenesis, strongly affecting both neuroblasts and astrocytes of the SEL. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 493–502, 2004
Differential expression of high voltage‐activated Ca2+ channel types in the rostral reticular thalamic nucleus of the absence epileptic WAG/Rij rat
Authors: van de Bovenkamp‐Janssen M.C. , Scheenen W.J.J.M. , Kuijpers‐Kwant F.J. , Kozicz T. , Veening J.G. , van Luijtelaar E.L.J.M. , McEnery M.W. , Roubos E.W. 
Published: February 2004

AbstractIn the WAG/Rij rat, a model for human absence epilepsy, spike‐wave discharges (SWD) and absence epileptic behavior develop after the age of 3 months. The rostral part of the reticular thalamic nucleus (rRTN) is involved in SWD. Ca2+ channels play a central role in the initiation and maintenance of burst firing activity of thalamic cells. We hypothesize that a changed expression of α1‐subunits of one or more high voltage‐activated Ca2+ channel types in the rRTN underlies the development of SWD. To test this hypothesis we compared 3‐ and 6‐month‐old WAG/Rij rats with nonepileptic, age‐matched control rats. By immunocytochemistry, the expressions of α11.3‐, α12.1‐, α12.2‐, and α12.3‐subunits were shown in both strains, demonstrating the presence of Cav1.3, Cav2.1, Cav2.2, and Cav2.3 channels, respectively. Quantification of channel expression indicates that the development of SWD in WAG/Rij rats is concomitant with an increased expression of Cav2.1 channels in the rRTN. These channels are mainly presynaptic, as revealed by double immunofluorescence involving the presynapse marker syntaxin. The mechanism by which this increase could be related to the occurrence of SWD has been discussed. © 2004 Wiley Periodicals, Inc. J Neurobiol 58: 467–478, 2004
CREB in the pond snail Lymnaea stagnalis: Cloning, gene expression, and function in identifiable neurons of the central nervous system
Authors: Sadamoto Hisayo , Sato Hanae , Kobayashi Suguru , Murakami Jun , Aonuma Hitoshi , Ando Hironori , Fujito Yutaka , Hamano Kaoru , Awaji Masahiko , Lukowiak Ken , Urano Akihisa , Ito Etsuro 
Published: February 2004

AbstractThe pond snail Lymnaea stagnalis is an excellent model system in which to study the neuronal and molecular substrates of associative learning and its consolidation into long‐term memory. Until now, the presence of cyclic AMP (cAMP)‐responsive element binding protein (CREB), which is believed to be a necessary component in the process of a learned behavior that is consolidated into long‐term memory, has only been assumed in Lymnaea neurons. We therefore cloned and analyzed the cDNA sequences of homologues of CREB1 and CREB2 and determined the presence of these mRNAs in identifiable neurons of the central nervous system (CNS) of L. stagnalis. The deduced amino acid sequence of Lymnaea CREB1 is homologous to transcriptional activators, mammalian CREB1 and Aplysia CREB1a, in the C‐terminal DNA binding (bZIP) and phosphorylation domains, whereas the deduced amino acid sequence of Lymnaea CREB2 is homologous to transcriptional repressors, human CREB2, mouse activating transcription factor‐4, and Aplysia CREB2 in the bZIP domain. In situ hybridization revealed that only a relatively few neurons showed strongly positive signals for Lymnaea CREB1 mRNA, whereas all the neurons in the CNS contained Lymnaea CREB2 mRNA. Using one of the neurons (the cerebral giant cell) containing Lymnaea CREB1 mRNA, we showed that the injection of a CRE oligonucleotide inhibited a cAMP‐induced, long‐lasting synaptic plasticity. We therefore conclude that CREBs are present in Lymnaea neurons and may function as necessary players in behavioral plasticity. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 455–466, 2004
Treatment with the antiepileptic drugs phenytoin and gabapentin ameliorates seizure and paralysis ofDrosophilabang‐sensitive mutants
Authors: Reynolds Elaine R. , Stauffer Eric A. , Feeney Laura , Rojahn Elizabeth , Jacobs Benjamin , McKeever Carol 
Published: February 2004

AbstractDrosophilabang‐sensitive (bs) mutants exhibit a stereotypic seizure and paralysis following exposure to mechanical shock. In a physiological preparation, seizures and failures corresponding to the defective behavior are observed in response to high frequency stimulation. The amplitude of the stimulus necessary to produce bs behavior, or seizure threshold, varies with bs mutant and its gene dosage. In many respects, the bs defects are similar to those observed in mammalian seizure disorders. Antiepileptic drugs (AEDs) were administered by feeding toeasily shocked2(eas2), a representative bs mutant. The mean recovery times of treated flies were examined in comparison to control cultures. Some of the drugs administered, including carbamazeprine, ethosuximide, and vigabactrin, had little or no effect on the bs behavior ofeas2. Gabapentin, however, showed a reduction in mean recovery time with chronic drug exposure. Phenytoin also had a significant effect on the bs behavior of treated flies. There was a reduction of both mean recovery time and the percentage of flies that displayed bang‐sensitive behavior with both acute and chronic treatment. The adult giant fiber preparation was used to examine the effects of phenytoin physiologically. Treatedeas2flies showed changes in their response to normal stimulation as well as alterations in seizure threshold in response to high frequency stimulation. Gabapentin was also effective against two other bs mutants,bangsenseless1andslamdanceiso7.8, at strain‐specific concentrations, while phenytoin also reduced bang‐sensitive behaviors inbangsenseless1in a dose dependent manner. AEDs, therefore, can be used to dissect aspects of bs behavior and this model may be useful in understanding the underlying basis of seizure disorders. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 503–513, 2004
Tyramine and octopamine have opposite effects on the locomotion of Drosophila larvae
Authors: Saraswati Sudipta , Fox Lyle E. , Soll David R. , Wu Chun‐Fang 
Published: February 2004

AbstractBiogenic amines are believed to play important roles in producing behaviors. Although some biogenic amines have been extensively studied in both vertebrates and invertebrates, little is known about the effects of trace amines like tyramine and octopamine. We investigated how trace amines affect behaviors using quantitative morphometric methods on Drosophila
TβhnM18 and iavN mutants that have altered levels of tyramine and octopamine. Locomotion of wild‐type and mutant third instar larvae was analyzed using Dynamic Image Analysis System (DIAS) software. We found that TβhnM18 mutants, with elevated tyramine levels and reduced octopamine levels, had a severe locomotion phenotype. Mutant larvae spent much more time in pausing episodes than wild‐type larvae and displayed a reduction in speed and linear translocation. The locomotion phenotype was partially rescued by feeding TβhnM18 larvae octopamine, an effect that could be nullified with simultaneous feeding of tyramine. Feeding TβhnM18 larvae yohimbine, an agent that inhibits the activity of Drosophila tyramine receptors, also improved some locomotion parameters. Feeding both octopamine and yohimbine further improved rescue efficiency. Simultaneously reducing the octopamine and tyramine levels as in iavN larvae, in contrast, led to a less severe behavioral phenotype than that of TβhnM18 mutants. Feeding iavN larvae either tyramine or octopamine exerted only a minor improvement in locomotion. These results suggest that tyramine and octopamine have opposite effects on Drosophila larval locomotion regulation and that a balance between the two is important in producing normal behavior. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 425–441, 2004
Developmental patterns of NMDAR expression within the song system do not recur during adult vocal plasticity in zebra finches
Authors: Scott Luisa L. , Singh Tryambak D. , Nordeen Ernest J. , Nordeen Kathy W. 
Published: February 2004

AbstractAll songbirds learn to sing during postnatal development but then display species differences in the capacity to learn song in adulthood. While the mechanisms that regulate avian vocal plasticity are not well characterized, one contributing factor may be the composition of N‐methyl‐D‐aspartate receptors (NMDAR). Previous studies of an anterior forebrain pathway implicated in vocal plasticity revealed significant regulation of NMDAR subunit expression during the developmental sensitive period for song learning. Much less is known about the developmental regulation of NMDAR subunit expression in regions that participate more directly in motor aspects of song behavior. We show here that an increase in NR2A subunit mRNA and a decrease in NR2B subunit mRNA within the vocal motor pathway accompany song learning in zebra finches; however, manipulations that can alter the timing of song learning did not alter the course of these developmental changes. We also tested whether adult deafening, a treatment that provokes vocal change in songbirds that normally sing a stable song throughout adulthood, would render NMDAR subunit expression more similar to that observed developmentally. We report that NR2A and NR2B mRNA levels did not change within the anterior forebrain or vocal motor pathways after adult deafening, even after substantial changes in song structure. These results indicate that vocal plasticity does not require “juvenile patterns” of NMDAR gene expression in the avian song system. © 2003 Wiley Periodicals, Inc. J Neurobiol 58: 442–454, 2004
Topographic regulation of phosphorylation in giant neurons of the squid, Loligo pealei: Role of phosphatases
Authors: Grant Philip , Pant Harish C. 
Published: February 2004

AbstractIn previous studies of phosphorylation in squid stellate ganglion neurons, we demonstrated that a specific multimeric phosphorylation complex characterized each cellular compartment. Although the endogenous protein profile of cell body extracts (giant fiber lobe, GFL), as determined by Coomassie staining, was similar to that of axoplasm from the giant axon, in this study we show that the protein phosphorylation profiles are qualitatively different. Whereas many axoplasm proteins were phosphorylated, including most cytoskeletal proteins, virtually all phosphorylation in perikarya was confined to low molecular weight compounds (<6 kDa). Because phosphorylation of exogenous substrates, histone and casein, was equally active in extracts from both compartments, failure to detect endogenous protein phosphorylation in cell bodies was attributed to the presence of more active phosphatases. To further explore the role of phosphatases in these neurons, we studied phosphorylation in the presence of serine/threonine and protein tyrosine phosphatase (PTP) inhibitors. We found that phosphorylation of axonal cytoskeletal proteins was modulated by okadaic acid‐sensitive ser/thr phosphatases, whereas cell body phosphorylation was more sensitive to an inhibitor of protein tyrosine phosphatases, such as vanadate. Inhibition of PTPs by vanadate stimulated endogenous phosphorylation of GFL proteins, including cytoskeletal proteins. Protein tyrosine kinase activity was equally stimulated by vanadate in cell body and axonal whole homogenates and Triton X‐100 free soluble extracts, but only the Triton X soluble fraction (membrane bound proteins) of the GFL exhibited significant activation in the presence of vanadate, suggesting higher PTP activities in this fraction than in the axon. The data are consistent with the hypothesis that neuronal protein phosphorylation in axons and cell bodies is modulated by different phosphatases associated with compartment‐specific multimeric complexes. © 2004 Wiley Periodicals, Inc. J Neurobiol 58: 514–528, 2004
Anionic non‐equilibrium ring‐opening polymerization of octamethylcyclotetrasiloxane (D4) initiated by silazyl‐lithiums
Authors: Su Shunxing , Zhang Zhijie , Zheng Zhimin , Xie Zemin 
Published: February 2004

AbstractThe initiation and propagation reactions in anionic non‐equilibrium polymerization of octamethylcyclotetrasiloxane (D4) initiated by silazyl‐lithiums are investigated. It is found that: both the steric hindrance effect and the electronic effect of the substitutes on the Si atom Si influences the initiation activity of silazyl‐lithiums; temperature effect on the propagation rate of D4 increases strongly above 40 °C; the molecular weight distribution of the prepared polysiloxanes widens with time.© 2003 Society of Chemical Industry
Specific interactions in miscible polymer blends of poly(2‐hydroxypropyl methacrylate) with polyvinylpyrrolidone
Authors: Kuo Shiao‐Wei , Shih Chien‐Chou , Shieh Jye‐Shiou , Chang Feng‐Chih 
Published: February 2004

AbstractThe miscibility behaviour and hydrogen‐bonding interaction in blends of poly(2‐hydroxypropyl methacrylate) (PHPMA) with polyvinylpyrrolidone (PVP) were characterized using differential scanning calorimetry and Fourier‐transform infrared spectra. This polymer blend was miscible over the whole composition range and an unusually large positive deviation of Tg from the linearity rule was observed, indicating strong hydrogen bonding between the hydroxyl group of PHPMA and the carbonyl group of PVP. Infrared spectroscopic analysis provided positive evidence for the intra‐molecular hydrogen bonding of PHPMA and inter‐molecular hydrogen bonding between PHPMA and PVP at various compositions and temperatures. Furthermore, equilibrium constants and enthalpies of self‐association and inter‐association between functional groups in the blend of PHPMA and PVP were calculated to explain the results. Copyright © 2004 Society of Chemical Industry
A water‐dispersible conducting nanocomposite from suspension polymerisation of thiophene in presence of N‐vinylcarbazole
Authors: Ballav Nirmalya , Biswas Mukul 
Published: February 2004

AbstractThe polymerisation of a mixture of thiophene and N‐vinylcarbazole was achieved in aqueous suspension in the presence of nanodimensional alumina and FeCl3 as oxidant. The resultant composite was found to contain both polythiophene (PTP) and poly(N‐vinylcarbazole) (PNVC) components even after reflux in benzene, which would remove any PNVC homopolymer. The presence of the individual polymer components was endorsed by FTIR spectroscopic analyses. Thermogravimetric analyses showed that the overall stabilities of the composite and the corresponding homopolymers were in the order: PTP–Al2O3 > PTP > PTP–PNVC–Al2O3 > PNVC. Differential thermal analyses studies showed the manifestation of two different exotherms corresponding to the presence of two different polymeric constituents in the PTP–PNVC–Al2O3 composite. Differential scanning calorimetry studies revealed two glass‐transition temperatures (Tg) suggesting the presence of two polymeric moieties in the PTP–PNVC composite. Scanning electron micrographs of the PTP–Al2O3 and PTP–PNVC–Al2O3 composites showed distinctive morphological patterns. Transmission electron microscopic images of the composite revealed that the average particle size varied between 20 and 80 nm. DC conductivities of the composites were of the order of 10−6 S cm−1. Copyright © 2003 Society of Chemical Industry
Study of miscibility enhancement in poly(styrene‐co‐4‐vinylphenol)/poly(ethylene oxide) blends by the spin labelling method
Authors: Tan Li , Chen Shiming , Ping Zhenghua , Shen Yimin 
Published: February 2004

AbstractThe electron spin resonance (ESR) spectra of end‐group spin labelled poly(ethylene oxide) (SLPEO) using 2,2,6,6‐tetramethyl‐piperdine‐1‐oxyl nitroxide and its blends with poly(styrene‐co‐4‐vinylphenol) (STVPhs) of different hydroxyl contents were recorded over a wide temperature range. For a blend of SLPEO and pure polystyrene (PS), the ESR spectrum was composed of a single motion component, indicating that PS was immiscible with PEO. For blends composed of SLPEO and different‐hydroxyl‐content STVPhs, two spectral components with different motion rates were observed over a certain temperature range. The difference between the motion rates should be attributed to micro‐heterogeneity in the blends, with the faster rate corresponding to a nitroxide radical motion trapped in the PEO‐rich domain and the slower rate corresponding to a nitroxide radical motion trapped in the STVPh‐rich domain. Variations in the values of a number of the ESR parameters (Ta, Td and T50G) and the apparent activation energy (Ea) with hydroxyl content in the blends indicated that the miscibility of the blends increased with increasing hydrogen‐bonding density due to specific interactions between the hydroxyl groups in STVPh and the ether oxygens in PEO. Copyright © 2004 Society of Chemical Industry
Analysis of the interfacial interactions in polypropylene/silica nanocomposites
Authors: Rong Min Zhi , Zhang Ming Qiu , Pan Shun Long , Lehmann Björn , Friedrich Klaus 
Published: February 2004

AbstractPolypropylene‐based composites were prepared by melt blending with nano‐silica, which was pre‐treated by grafting polymerization onto the surface. Tensile moduli and strengths of the composites were determined as a function of the nano‐silica content and the amount of the grafting polymers chemically attached to the nanoparticles, ie percentage grafting. To analyse the relationships between the interfacial interactions in the composites and tensile performance, a number of models dealing with the static and dynamic mechanical behaviours of the particulate composites were applied. It was found that stronger interfacial interactions exist in the grafted nano‐silica‐filled polypropylene composites as compared to the composites with untreated nano‐silica. Since the interfacial interactions occur only within a very short range, the greatest interaction between the modified nanoparticles and the matrix is achieved in the case of low silica concentration and low percentage grafting. An increase in the percentage grafting for various grafted nanoparticles definitely results in an increase of interphase thickness, but the interfacial interactions and the tensile performance of the composites are not necessarily improved because the agglomeration structure of the nanoparticles and the miscibility between the components play the leading role. Copyright © 2004 Society of Chemical Industry
Synthesis of novel poly(vinyl ether)s containing the oxybenzylidenemalononitrile group as a nonlinear optical chromophore, and their electro‐optic properties
Authors: Lee Ju‐Yeon , Lee Won‐Jung , Rhee Bum Ku , Min Hae Sik 
Published: February 2004

Abstract2,4‐Di‐(2′,2′‐dicyanovinyl)‐1‐(2′‐vinyloxyethoxy)benzene and 2,4‐di‐(2′‐carbomethoxy‐2′‐cyanovinyl)‐1‐(2′‐vinyloxyethoxy)benzene were prepared by condensation of 4‐(2′‐vinyloxyethoxy)isophthaldehyde with malononitrile and methyl cyanoacetate, respectively. The two vinyl monomers were polymerized with boron trifluoride etherate as a cationic initiator to yield poly(vinyl ether)s containing two oxybenzylidenemalononitrile and oxybenzylidenecyanoacetate groups, which are effective chromophores for second‐order nonlinear optical applications. These polymers were soluble in common organic solvents such as acetone and dimethyl sulforide. They showed thermal stabilities up to 300 °C from thermogravimetric analysis (TGA), with differential scanning calorimeter (DSC) thermograms giving Tg values in the range 73–87 °C. The second harmonic generation (SHG) coefficients (d33) of poled polymer films were around 1.8 × 10−9 esu, and these polymers showed good long‐term thermal stability for 60 days at room temperature, which is acceptable for nonlinear optical (NLO) device applications. Copyright © 2004 Society of Chemical Industry
Preparation and characterization of poly(vinyl chloride)/organoclay nanocomposites by in situ intercalation
Authors: Haiyan Hu , Mingwang Pan , Xiucuo Li , Xudong Shi , Liucheng Zhang 
Published: February 2004

AbstractIn this article, poly(vinyl chloride) (PVC)–organoclay nanocomposites were prepared via in situ polymerization intercalation and melt blending intercalation, respectively. Their nanostructures were characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Differences in the morphologies of the PVC hybrids prepared by in situ intercalation and melt intercalation were investigated. In addition, three kinds of organoclay were used, in order to consider the effect of the interlayer environment on intercalation. The results show that ammonium cations have a great influence on the hybrids prepared by melt intercalation, while they have no obvious effect on the nanostructures of the composites produced via in situ intercalation due to its distinctive process and its mechanism. Copyright © 2004 Society of Chemical Industry
Synthesis of well‐defined comb‐like amphiphilic copolymers with protonizable units in the pendent chains: 2. Poly(2‐(dimethylamino)ethyl methacrylate) grafted poly(methyl methacrylate‐co‐2‐hydroxyethyl methacrylate) copolymers and their association behavior in aqueous solution
Authors: Jin Lan , Liu Ping , Hu Jianhua , Wang Changchun 
Published: February 2004

AbstractNarrow‐distribution, well‐defined comb‐like amphiphilic copolymers are reported in this work. The copolymers are composed of poly(methyl methacrylate‐co‐2‐hydroxyethyl methacrylate) (P(MMA‐co‐HEMA)) as the backbones and poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA) as the grafted chains, with the copolymer backbones being synthesized via atom‐transfer radical polymerization (ATRP) and the grafted chains by oxyanionic polymerization. The copolymers were characterized by gel permeation chromatography (GPC), Fourier‐transform infrared (FT‐IR) spectroscopy and 1H NMR spectroscopy. The aggregation behavior in aqueous solutions of the comb‐like amphiphilic copolymers was also investigated. 1H NMR spectroscopic and surface tension measurements all indicated that the copolymers could form micelles in aqueous solutions and they possessed high surface activity. The results of dynamic light scattering (DLS) and scanning electron microscopy (SEM) investigations showed that the hydrodynamic diameters of the comb‐like amphiphilic copolymer aggregates increased with dilution. Because of the protonizable properties of the graft chains, the surface activity properties and micellar state can be easily modulated by variations in pH. Copyright © 2004 Society of Chemical Industry