bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dietary retinoic acid affects song maturation and gene expression in the song system of the zebra finch
Authors: Wood William E. , Olson Christopher R. , Lovell Peter V. , Mello Claudio V. 
Published: June 2008

AbstractVitamin A, an essential nutrient, is required in its acidic form (retinoic acid) for normal embryogenesis and neuronal development, typically within well‐defined concentration ranges. In zebra finches, a songbird species, localized retinoic acid synthesis in the brain is important for the development of song, a learned behavior sharing significant commonalities with speech acquisition in humans. We tested how dietary retinoic acid affects the development of song behavior and the brain's system for song control. Supplemental doses of retinoic acid given to juveniles during the critical period for song learning resulted in more variable or plastic‐like songs when the birds reached adulthood, compared to the normal songs of vehicle‐fed controls. We also observed that several genes (brinp1, nrgn, rxr‐α, and sdr2/scdr9) had altered levels of expression in specific nuclei of the song system when comparing the experimental and control diet groups. Interestingly, we found significant correlations between gene expression levels in nuclei of the anterior forebrain pathway (lMAN and area X) and the degree of variability in the recorded songs. We observed, however, no major morphological effects such as changes in the volumes of song nuclei. Overall, our results lend further support to a fundamental role of retinoic acid in song maturation and point to possible molecular pathways associated with this action. The data also demonstrate that dietary content of Vitamin A can affect the maturation of a naturally learned complex behavior. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Identification of Drosophila type II neuroblast lineages containing transit amplifying ganglion mother cells
Authors: Boone Jason Q. , Doe Chris Q. 
Published: June 2008

AbstractMammalian neural stem cells generate transit amplifying progenitors that expand the neuronal population, but these type of progenitors have not been studied in Drosophila. The Drosophila larval brain contains ∼100 neural stem cells (neuroblasts) per brain lobe, which are thought to bud off smaller ganglion mother cells (GMCs) that each produce two post‐mitotic neurons. Here, we use molecular markers and clonal analysis to identify a novel neuroblast cell lineage containing “transit amplifying GMCs” (TA‐GMCs). TA‐GMCs differ from canonical GMCs in several ways: each TA‐GMC has nuclear Deadpan, cytoplasmic Prospero, forms Prospero crescents at mitosis, and generates up to 10 neurons; canonical GMCs lack Deadpan, have nuclear Prospero, lack Prospero crescents at mitosis, and generate two neurons. We conclude that there are at least two types of neuroblast lineages: a Type I lineage where GMCs generate two neurons, and a type II lineage where TA‐GMCs have longer lineages. Type II lineages allow more neurons to be produced faster than Type I lineages, which may be advantageous in a rapidly developing organism like Drosophila. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
The development of intrinsic excitability in mouse retinal ganglion cells
Authors: Qu Juan , Myhr Karen L. 
Published: June 2008

AbstractActivity‐dependent refinement of synaptic connections occurs throughout the developing nervous system, including the visual system. Retinal ganglion cells (RGCs) overproduce synapses then refine them in an activity‐dependent manner that segregates RGC connections into multicellular patterns, such as eye‐specific regions and retinotopic maps. Ferrets additionally segregate ON and OFF retinogeniculate pathways in an activity‐dependent manner. It was unknown whether differences in ON versus OFF intrinsic and spontaneous activity occur in postnatal mouse. The work reported here measured the intrinsic properties and spontaneous activity of morphologically identified postnatal mouse RGCs, and tested the hypothesis that mouse ON and OFF RGCs develop differences in spontaneous activity. We found developmental changes in resting potential, action potential threshold, depolarization to threshold, action potential width, action potential patterns, and maximal firing rates. These results are consistent with the maturation of the intrinsic properties of RGCs extending through the first three postnatal weeks. However, there were no differences among mouse ON, OFF, and multistratified RGCs in intrinsic excitability, spontaneous synaptic drive or spontaneous action potential patterns. The absence of differences between ON and OFF activity patterns is unlike the differences that arise in ferrets. In contrast to the ferret, the ON and OFF target neurons in the mouse are organized in a random pattern, not layers. This supports the hypothesis that the absence of systematic differences in activity results in the nonlayered distribution of retinogeniculate connections. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Normal dendrite growth in Drosophila motor neurons requires the AP‐1 transcription factor
Authors: Hartwig Cortnie L. , Worrell Jason , Levine Richard B. , Ramaswami Mani , Sanyal Subhabrata 
Published: June 2008

AbstractDuring learning and memory formation, information flow through networks is regulated significantly through structural alterations in neurons. Dendrites, sites of signal integration, are key targets of activity‐mediated modifications. Although local mechanisms of dendritic growth ensure synapse‐specific changes, global mechanisms linking neural activity to nuclear gene expression may have profound influences on neural function. Fos, being an immediate‐early gene, is ideally suited to be an initial transducer of neural activity, but a precise role for the AP‐1 transcription factor in dendrite growth remains to be elucidated. Here we measure changes in the dendritic fields of identified Drosophila motor neurons in vivo and in primary culture to investigate the role of the immediate‐early transcription factor AP‐1 in regulating endogenous and activity‐induced dendrite growth. Our data indicate that (a) increased neural excitability or depolarization stimulates dendrite growth, (b) AP‐1 (a Fos, Jun hetero‐dimer) is required for normal motor neuron dendritic growth during development and in response to activity induction, and (c) neuronal Fos protein levels are rapidly but transiently induced in motor neurons following neural activity. Taken together, these results show that AP‐1 mediated transcription is important for dendrite growth, and that neural activity influences global dendritic growth through a gene‐expression dependent mechanism gated by AP‐1. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Three‐Dimensionally Ordered CDW State in Quasi‐One‐Dimensional Iodo‐Bridged Dinuclear Platinum Mixed‐Valence Compounds, A4[Pt2I(pop)4]·nH2O (A = Aromatic Ammonium Cations)
Authors: Matsunaga Satoshi , Takizawa Kouichi , Kawakami Daisuke , Iguchi Hiroaki , Takaishi Shinya , Kajiwara Takashi , Miyasaka Hitoshi , Yamashita Masahiro , Matsuzaki Hiroyuki , Okamoto Hiroshi 
Published: June 2008

AbstractLinear‐chain iodo‐bridged dinuclear Pt mixed‐valence compounds with aromatic ammonium countercations, A4[Pt2I(pop)4]·nH2O [pop = P2O5H22–, A = benzyl ammonium (n = 2; 1), anilinium (n = 2; 2), and p‐methoxy anilinium (n = 2; 3)], that have three‐dimensionally ordered structures were synthesized. In the case of 1–3 the aromatic ammonium countercations were located between neighboring Pt chains and stacked in 1D columns. π–π Interactions between the phenyl rings and hydrogen bonds between the –NH3+ moieties and the oxygen atoms of the pop ligand link the Pt chains together, thus giving rise to a three‐dimensionally ordered CDW state. This is the first observation of this phenomenon in compounds of this type.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Unprecedented N‐Inserted Disulfide Ligand Stabilized by Coordination to the Electropositive CoIII Center
Authors: Yoo Houng Sik , Yoon Jung Hee , Kim Jae Il , Koh Eui Kwan , Hong Chang Seop 
Published: June 2008

AbstractThe reaction of CoII and 2,2′‐dipyridyldisulfide (PySSPy) in the presence of azide produced a peculiar monomeric complex [CoIII(PyS)(PyS‐N‐SPy)(N3)] (1). In this reaction, redox chemistry takes place, which is associated mainly with the oxidation of CoII to CoIII and the reduction of PySSPy. During the reaction, the azide ion decomposes and donates a nitrogen atom to PySSPy. The crystal structure of 1 provides evidence that the unusual, N‐inserted ligand PyS‐N‐SPy can be stabilized through coordination to the electropositive CoIII ion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Superacid‐Catalyzed Dimerization/Cyclization of Isopropenyl‐PAHs – Novel Pathways to PAH Dimers, Phenalenes and Their Stable Carbocations
Authors: Brulé Cédric , Sultana Fatima , Hollenstein Sandro , Okazaki Takao , Laali Kenneth K. 
Published: June 2008

AbstractThe isopropenyl derivatives of representative classes of polycyclic aromatic hydrocarbons (PAHs) having four and five fused‐ring systems, namely pyrene, chrysene, benzo[c]phenanthrene (BcPh), dibenzo[a,c]anthracene (benzo[f]tetraphene) and perylene, were synthesized by Wittig olefination from the corresponding acetyl‐PAHs. Under the influence of triflic acid (TfOH), the isopropenyl derivatives were converted to novel PAH dimers and/or phenalenes in a simple one‐pot procedure. A plausible mechanism for this process has been outlined, and the synthetic scope of this chemistry has been explored. Structural features in the PAH dimers were examined by DFT. As representative initial and final carbocation intermediates in the reaction sequence, stable carbocations derived from 3‐isopropenylperylene and from 4,6,6‐trimethyl‐6H‐dibenzo[a,kl]anthracene were generated and studied directly by NMR spectroscopy. The NMR characteristics and charge delocalization modes in the resulting benzylic carbocations are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Bovine red blood cell starvation age discrimination through a glutaraldehyde‐amplified dielectrophoretic approach with buffer selection and membrane cross‐linking
Authors: Gagnon Zachary , Gordon Jason , Sengupta Shramik , Chang Hsueh‐Chia 
Published: June 2008

AbstractWe report a novel buffer electric and dielectric relaxation time tuning technique, coupled with a glutaraldehyde (Glt.) cross‐linking cell fixation reaction that allows for sensitive dielectrophoretic analysis and discrimination of bovine red blood cells of different starvation age. Guided by a single‐shell oblate spheroid model, a zwitterion buffer composition is selected to ensure that two measurable crossover frequencies (cof's) near 500 kHz exist for dielectrophoresis (DEP) within a small range of each other. It is shown that the low cof is sensitive to changes in the cell membrane dielectric constant, in which cross‐linking by Glt. reduces the dielectric constant of the cell membrane from 10.5 to 3.8, while the high cof is sensitive to cell cytoplasm conductivity changes. We speculate that this enhanced particle polarizability that results from the cross‐linking reaction is because younger (reduced starvation time) cells possess more amino groups that the reaction can release to enhance the cell interior ionic strength. Such sensitive discrimination of cells with different age (surface protein density) by DEP is not possible without the zwitterion buffer and cleavage by Glt. treatment. It is then expected that rapid identification and sorting of healthy from diseased cells can be similarly sensitized.
Bulk electrical properties of single‐walled carbon nanotubes immobilized by dielectrophoresis: Evidence of metallic or semiconductor behavior
Authors: Mureau Natacha , Watts Paul C. P. , Tison Yann , Silva S. Ravi P. 
Published: June 2008

AbstractWe report the electrical characterization of single‐walled carbon nanotubes (SWCNTs) trapped between two electrodes by dielectrophoresis (DEP). At high frequency, SWCNTs collected by DEP are expected to be of metallic type. Indeed current‐voltage (I‐V) measurements for devices made at 10 MHz show high values of conductivity and exhibit metallic behavior with linear and symmetric electrical features attributed to ohmic conduction. At low frequency, SWCNTs attracted by DEP are expected to be of semiconducting nature. Devices made at 10 kHz behave as semiconductors and demonstrate nonlinear and rectifying electrical characteristics with conductivities many orders of magnitude below the sample resulting from high‐frequency immobilization of SWCNTs. Conducting atomic force microscopy (C‐AFM) and current density calculation results are presented to reinforce results obtained by I‐V measurements which clearly show type separation of SWCNTs after DEP experiments.
Cortical compensation associated with dysphagia caused by selective degeneration of bulbar motor neurons
Authors: Dziewas Rainer , Teismann Inga K. , Suntrup Sonja , Schiffbauer Hagen , Steinstraeter Olaf , Warnecke Tobias , Ringelstein Erich‐Bernd , Pantev Christo 
Published: June 2008

AbstractAccording to recent neuroimaging studies, swallowing is processed within multiple regions of the human brain. In contrast to this, little is known about the cortical contribution and compensatory mechanisms produced by impaired swallowing. In the present study, we therefore investigated the cortical topography of volitional swallowing in patients with X‐linked bulbospinal neuronopathy (Kennedy disease, KD). Eight dysphagic patients with genetically proven KD and an age‐matched healthy control group were studied by means of whole‐head magnetoencephalography using a previously established swallowing paradigm. Analysis of data was carried out with synthetic aperture magnetometry (SAM). The group analysis of individual SAM results was performed using a permutation test. KD patients showed significantly larger swallow‐related activation of the bilateral primary sensorimotor cortex than healthy controls. In contrast to the control group, in KD patients the maximum activity was located in the right sensorimotor cortex. Furthermore, while in nondysphagic subjects a previously described time‐dependent shift from the left to the right hemisphere was found during the one second of most pronounced swallow‐related muscle activity, KD patients showed a strong right hemispheric activation in each time segment analyzed. Since the right hemisphere has an established role in the coordination of the pharyngeal phase of swallowing, the stronger right hemispheric activation observed in KD patients indicates cortical compensation of pharyngeal phase dysphagia. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.
Paired‐pulse depression of excitatory postsynaptic current sinks in hippocampal CA1 in vivo
Authors: Leung L. Stan , Peloquin Pascal , Canning Kevin J. 
Published: June 2008

AbstractPaired‐pulse depression (PPD), a short‐term neural plasticity, was studied in hippocampal CA1 of urethane‐anesthetized rats in vivo, using field potential recordings and current source density analysis. PPD was robust when an ipsilateral CA3 (iCA3) conditioning pulse of moderate stimulus intensity was followed 30–200 ms later by a contralateral CA3 (cCA3) test pulse; the ratio of the conditioned (C) to the nonconditioned (NC) response, as measured by the peak excitatory sink at the apical dendrites, ranged from 0.6 to 0.8. An alveus conditioning pulse evoked a large antidromic population spike in CA1 and a modest depression of the CA3‐evoked excitatory sink (C/NC ratio of ∼0.85). High‐intensity paired pulses, both delivered to iCA3, also showed PPD of the proximal excitatory sinks; however, paired‐pulse facilitation of the dendritic sinks was found at the mid‐apical dendrites, >250 μm from the soma. Local injection of GABAA antagonist picrotoxin or bicuculline increased the C/NC ratio at IPIs of <150 ms, as well as the ratio of the amplitude of the population spikes (P2/P1; where P2 and P1 are the population spikes evoked by the second and first pulse, respectively). GABAB receptor antagonists, CGP35348 given intracerebroventricularly or CGP56999A administered locally, increased C/NC and P2/P1 at IPIs of 150–400 ms. It is concluded that conditioned depression of the excitatory sinks was caused by mainly feedforward and some feedback inhibition at the apical dendrites. GABAA‐mediated postsynaptic inhibition dominated at early latencies, while GABAB‐mediated inhibition prevailed at long latencies, probably at both presynaptic and postsynaptic sites. PPD of the excitatory sinks provides a measure of population dendritic inhibition in vivo. © 2008 Wiley‐Liss, Inc.
S‐ketamine and GABA‐A‐receptor interaction in humans: an exploratory study with I‐123‐iomazenil SPECT
Authors: Heinzel Alexander , Steinke Rainer , Poeppel Thorsten Dirk , Grosser Oliver , Bogerts Bernhard , Otto Hans , Northoff Georg 
Published: June 2008

AbstractObjectiveWe aimed to probe for regional cerebral effects of S‐ketamine on in vivo GABA‐A‐receptor binding in healthy human subjects.MethodsWe investigated I‐123‐iomazenil SPECT before, during and after administration of S‐ketamine in a blinded placebo‐controlled study design (n = 12 in both groups). Analyses of SPECT were performed with voxel‐based statistical parametric mapping (SPM), and statistical comparisons were made between the groups. We also assessed biochemical and behavioural changes during S‐ketamine infusion.ResultsS‐ketamine induced positive and negative symptoms measured by the Brief Psychiatric Rating scale (BPRS). It increased the cortisol and prolactin levels. Image analysis revealed significantly decreased I‐123‐iomazenil binding in bilateral dorsomedial prefrontal cortex during S‐ketamine administration when compared to placebo.ConclusionOur study delivers preliminary evidence for an in vivo interaction of S‐ketamine with GABA‐A‐receptors in human dorsomedial prefrontal cortex. Copyright © 2008 John Wiley & Sons, Ltd.
Activation of NF‐κB by extracellular S100A4: Analysis of signal transduction mechanisms and identification of target genes
Authors: Boye Kjetil , Grotterød Ida , Aasheim Hans‐Christian , Hovig Eivind , Mælandsmo Gunhild M. 
Published: June 2008

AbstractThe metastasis‐promoting protein S100A4 stimulates metastatic progression through both intracellular and extracellular functions. Extracellular activities of S100A4 include stimulation of angiogenesis, regulation of cell death and increased cell motility and invasion, but the exact molecular mechanisms by which extracellular S100A4 exerts these effects are incompletely elucidated. The aim of the present study was to characterize S100A4‐induced signal transduction mechanisms and to identify S100A4 target genes. We demonstrate that extracellular S100A4 activates the transcription factor NF‐κB in a subset of human cancer cell lines through induction of phosphorylation and subsequent degradation of the NF‐κB inhibitor IκBα. Concomitantly, S100A4 induced a sustained activation of the MAP kinase JNK, whereas no increased activity of the MAP kinases p38 or ERK was observed. Microarray analyses identified 136 genes as being significantly regulated by S100A4 treatment, and potentially interesting S100A4‐induced gene products include IκBα, p53, ephrin‐A1 and optineurin. Increased expression of ephrin‐A1 and optineurin was validated using RT‐PCR, Western blotting and functional assays. Furthermore, S100A4‐stimulated transcription of these target genes was dependent on activation of the NF‐κB pathway. In conclusion, these findings contribute to the understanding of the complex molecular mechanisms responsible for the diverse biological functions of extracellular S100A4, and provide further evidence of how S100A4 may stimulate metastatic progression. © 2008 Wiley‐Liss, Inc.
Chronic rhinosinusitis and risk of lung cancer in the Singapore Chinese Health Study
Authors: Koh Woon‐Puay , Yuan Jian‐Min , Wang Renwei , Seow Adeline , Lee Hin‐Peng , Yu Mimi C. 
Published: June 2008

AbstractEpidemiologic evidence suggests that chronic inflammatory conditions of the lung may increase lung cancer risk. These chronic conditions, such as chronic obstructive pulmonary disease and asthma, commonly coexist with chronic rhinosinusitis. We prospectively examined if chronic rhinitis or sinusitis was associated with lung cancer risk in the Singapore Chinese Health Study, a population‐based cohort of 63,257 Singapore Chinese, who were aged 45–74 years when recruited between 1993 and 1998. Each subject completed a comprehensive interview on medical conditions, dietary and lifestyle factors at recruitment, and cancer occurrence and survival status were determinedvialinkage to population‐based registries. As of 31 December, 2005, 954 cohort participants had developed lung cancer. Compared with subjects without such history, subjects who reported a history of physician‐diagnosed rhinitis or sinusitis at baseline, whether allergic or nonallergic, had a statistically significant 59% increase in risk of lung cancer (hazard ratio [HR] = 1.59; confidence interval [CI] = 1.06–2.37). This association was significant and stronger in women (HR = 2.32; 95% CI = 1.23–4.39) compared to men, and for the adenocarcinoma cell type (HR = 1.91; 95% CI = 1.07–3.42) compared to other histologies. Overall, a history of asthma, hay fever, allergic dermatitis, food allergy or any other allergic conditions asked in a single question was not related to lung cancer risk (HR = 1.11; 95% CI = 0.90–1.36). Chronic rhinosinusitis may be a marker of pan‐airway inflammation and its association with lung cancer risk provides evidence linking inflammation to lung carcinogenesis, especially among women. © 2008 Wiley‐Liss, Inc.
Gene expression and methylation status of 14‐3‐3σ in human renal carcinoma tissues
Authors: Liang Shufang , Xu Yuhuan , Shen Guobo , Zhao Xinyu , Zhou Jin , Li Xingbin , Gong Fengming , Ling Bo , Fang Li , Huang Canhua , Wei Yuquan 
Published: June 2008

AbstractLoss of 14‐3‐3σ expression mainly by methylation‐mediated silencing has been reported in several human cancers, but the methylation status of 14‐3‐3σ in human renal carcinoma is rarely studied so far. In this report, 14‐3‐3σ expression was first examined by RT‐PCR and immunohistochemistry, and further we investigated the methylation status by methylation‐specific PCR and the correlation between 14‐3‐3σ expression and its methylation. We found 14‐3‐3σ expression was lost in 27 of 31 renal tissues including 16 renal carcinoma tissues, eight para‐cancerous kidney tissues and seven normal kidney tissues. Among 16 renal carcinoma tissues, 14 cases had complete hypermethylation of 14‐3‐3σ. Eight para‐cancerous kidney tissues were almost completely methylated except one case had both methylation and unmethylation. Among seven normal kidney tissues, five cases had partial methylation, and the other two cases were completely methylated. In addition, 14‐3‐3σ mRNA had weak expression in OS‐RC‐2 cells, but it increased with gradual demethylation after treatment by a demethylation agent, 5‐aza‐2′‐deoxycytidine. In general, 14‐3‐3σ mRNA was mostly unexpressed, and its DNA frequently hypermethylated within 14‐3‐3σ coding region was closely associated with the gene silencing in cancerous and para‐cancerous kidney tissues. 14‐3‐3σ was also frequently methylated and almost silencing in normal kidney tissues. However, the methylation frequency was gradually reinforced with the extent of malignancy from normal to para‐cancerous and cancerous kidney tissues. © 2008 IUBMB IUBMB Life, 60(8): 534–540, 2008