bluuebunny/crossref_metadata_2025 huggingface dataset:
CYP1B1 expression promotes the proangiogenic phenotype of endothelium through decreased intracellular oxidative stress and thrombospondin-2 expression
Authors: Tang Yixin , Scheef Elizabeth A. , Wang Shoujian , Sorenson Christine M. , Marcus Craig B. , Jefcoate Colin R. , Sheibani Nader
Published: November 2008

Reactive species derived from cell oxygenation processes play an important role in vascular homeostasis and the pathogenesis of many diseases including retinopathy of prematurity. We show that CYP1B1-deficient (CYP1B1−/−) mice fail to elicit a neovascular response during oxygen-induced ischemic retinopathy. In addition, the retinal endothelial cells (ECs) prepared from CYP1B1−/− mice are less adherent, less migratory, and fail to undergo capillary morphogenesis. These aberrant cellular responses were completely reversed when oxygen levels were lowered or an antioxidant added. CYP1B1−/− ECs exhibited increased oxidative stress and expressed increased amounts of the antiangiogenic factor thrombospondin-2 (TSP2). Increased lipid peroxidation and TSP2 were both observed in retinas from CYP1B1−/− mice and were reversed by administration of an antioxidant. Reexpression of CYP1B1 in CYP1B1−/− ECs resulted in down-regulation of TSP2 expression and restoration of capillary morphogenesis. A TSP2 knockdown in CYP1B1−/− ECs also restored capillary morphogenesis. Thus, CYP1B1 metabolizes cell products that modulate intracellular oxidative stress, which enhances production of TSP2, an inhibitor of EC migration and capillary morphogenesis. Evidence is presented that similar changes occur in retinal endothelium in vivo to limit neovascularization.
A new approach to fitting induced-polarization spectra
Authors: Nordsiek Sven , Weller Andreas
Published: November 2008

Best fitting of induced-polarization (IP) spectra by different models of Cole-Cole type evidences discrepancies in the resulting model parameters. The time constant determined from the same data could vary in magnitude over several decades. This effect, which makes an evaluation of the results of different models nearly impossible, is demonstrated by induced polarization measurements in the frequency range between [Formula: see text] and [Formula: see text] on thirteen mixtures of quartz sand and slag grains. The samples differ in size and the amount of the slag grains. Parameters describing the IP spectra are derived by fitting models of the Cole-Cole type to the measured data. The fitting quality of the generalized Cole-Cole model, the standard Cole-Cole model, and the Cole-Davidson model is investigated. The parameters derived from these models are compared and correlated with mass percentage and grain size of the slag particles. An alternative fittingapproach is introduced, using the decomposition of observed IP spectra into a variety of Debye spectra. Four integrating parameters are derived and correlated with parameters of the slag-sand mixtures and Cole-Cole parameters, respectively. The alternative approach generally enables a better fitting of measured spectra compared with Cole-Cole type models. It proves to be more flexible and stable, even for complicated phase spectra that cannot be fitted by single Cole-Cole type models. The integrating parameters are well correlated with characterizing parameters of the slag-sand mixtures. The total chargeability well indicates the mass percentage of slag grains, and the mean relaxation time is related to the grain size. The relaxation time distribution can be displayed by cumulative normalized chargeability versus relaxation time, similar to granulation curves. Anologous to the latter, a nonuniformity parameter characterizes the width of the relaxation time distribution.
The leukemogenic t(8;21) fusion protein AML1-ETO controls rRNA genes and associates with nucleolar-organizing regions at mitotic chromosomes
Authors: Bakshi Rachit , Zaidi Sayyed K. , Pande Sandhya , Hassan Mohammad Q. , Young Daniel W. , Montecino Martin , Lian Jane B. , van Wijnen Andre J. , Stein Janet L. , Stein Gary S.
Published: November 2008

RUNX1/AML1 is required for definitive hematopoiesis and is frequently targeted by chromosomal translocations in acute myeloid leukemia (AML). The t(8;21)-related AML1-ETO fusion protein blocks differentiation of myeloid progenitors. Here, we show by immunofluorescence microscopy that during interphase, endogenous AML1-ETO localizes to nuclear microenvironments distinct from those containing native RUNX1/AML1 protein. At mitosis, we clearly detect binding of AML1-ETO to nucleolar-organizing regions in AML-derived Kasumi-1 cells and binding of RUNX1/AML1 to the same regions in Jurkat cells. Both RUNX1/AML1 and AML1-ETO occupy ribosomal DNA repeats during interphase, as well as interact with the endogenous RNA Pol I transcription factor UBF1. Promoter cytosine methylation analysis indicates that RUNX1/AML1 binds to rDNA repeats that are more highly CpG methylated than those bound by AML1-ETO. Downregulation by RNA interference reveals that RUNX1/AML1 negatively regulates rDNA transcription, whereas AML1-ETO is a positive regulator in Kasumi-1 cells. Taken together, our findings identify a novel role for the leukemia-related AML1-ETO protein in epigenetic control of cell growth through upregulation of ribosomal gene transcription mediated by RNA Pol I, consistent with the hyper-proliferative phenotype of myeloid cells in AML patients.
Effect of cell shape and packing density on granulosa cell proliferation and formation of multiple layers during early follicle development in the ovary
Authors: Da Silva-Buttkus Patricia , Jayasooriya Gayani S. , Mora Jocelyn M. , Mobberley Margaret , Ryder Timothy A. , Baithun Marianne , Stark Jaroslav , Franks Stephen , Hardy Kate
Published: November 2008

The postnatal mouse ovary is rich in quiescent and early-growing oocytes, each one surrounded by a layer of somatic granulosa cells (GCs) on a basal lamina. As oocytes start to grow the GCs change shape from flattened to cuboidal, increase their proliferation and form multiple layers, providing a unique model for studying the relationship between cell shape, proliferation and multilayering within the context of two different intercommunicating cell types: somatic and germ cells. Proliferation of GCs was quantified using immunohistochemistry for Ki67 and demonstrated that, unusually, cuboidal cells divided more than flat cells. As a second layer of GCs started to appear, cells on the basal lamina reached maximum packing density and the axes of their mitoses became perpendicular to the basal lamina, resulting in cells dividing inwards to form second and subsequent layers. Proliferation of basal GCs was less than that of inner cells. Ultrastructurally, collagen fibrils outside the basal lamina became more numerous as follicles developed. We propose that the basement membrane and/or theca cells that surround the follicle provide an important confinement for rapidly dividing columnar cells so that they attain maximum packing density, which restricts lateral mitosis and promotes inwardly oriented cell divisions and subsequent multilayering.
Community-Based Nonwork Supports: Findings From the National Survey of Day and Employment Programs for People With Developmental Disabilities
Authors: Sulewski Jennifer Sullivan , Butterworth John , Gilmore Dana
Published: November 2008

This article presents findings on community-based nonwork (CBNW; activities that do not involve paid employment but take place in the community) from a 2001 survey of state intellectual disabilities/developmental disabilities agency directors. Survey responses indicated that CBNW is a considerable and growing part of the day services mix but that it is loosely defined with respect to requirements, activities, populations served, and goals. Although CBNW has the potential to enhance the lives of people with disabilities, these findings raise some concerns, including how quality can be assured when supports are loosely defined, how CBNW can be provided without taking resources away from supported employment, and whether community connections can be made when people are supported in groups.
Synapsins Are Late Activity-Induced Genes Regulated by Birdsong
Authors: Velho Tarciso A. F. , Mello Claudio V.
Published: November 2008

The consolidation of long-lasting sensory memories requires the activation of gene expression programs in the brain. Despite considerable knowledge about the early components of this response, little is known about late components (i.e., genes regulated 2–6 h after stimulation) and the relationship between early and late genes. Birdsong represents one of the best natural behaviors to study sensory-induced gene expression in awake, freely behaving animals. Here we show that the expression of several isoforms of synapsins, a group of phosphoproteins thought to regulate the dynamics of synaptic vesicle storage and release, is induced by auditory stimulation with birdsong in the caudomedial nidopallium (NCM) of the zebra finch (Taeniopygia guttata) brain. This induction occurs mainly in excitatory (non-GABAergic) neurons and is modulated (suppressed) by early song-inducible proteins. We also show that ZENK, an early song-inducible transcription factor, interacts with thesyn3promoterin vivo, consistent with a direct regulatory effect and an emerging novel view of ZENK action. These results demonstrate that synapsins are a late component of the genomic response to neuronal activation and that their expression depends on a complex set of regulatory interactions between early and late regulated genes.
Loss of γ-Secretase Function Impairs Endocytosis of Lipoprotein Particles and Membrane Cholesterol Homeostasis
Authors: Tamboli Irfan Y. , Prager Kai , Thal Dietmar R. , Thelen Karin M. , Dewachter Ilse , Pietrzik Claus U. , St. George-Hyslop Peter , Sisodia Sangram S. , De Strooper Bart , Heneka Michael T. , Filippov Mikhail A. , Müller Ulrike , van Leuven Fred , Lütjohann Dieter , Walter Jochen
Published: November 2008

Presenilins (PSs) are components of the γ-secretase complex that mediates intramembranous cleavage of type I membrane proteins. We show that γ-secretase is involved in the regulation of cellular lipoprotein uptake. Loss of γ-secretase function decreased endocytosis of low-density lipoprotein (LDL) receptor. The decreased uptake of lipoproteins led to upregulation of cellular cholesterol biosynthesis by increased expression of CYP51 and enhanced metabolism of lanosterol. Genetic deletion of PS1 or transgenic expression of PS1 mutants that cause early-onset Alzheimer's disease led to accumulation of γ-secretase substrates and mistargeting of adaptor proteins that regulate endocytosis of the LDL receptor. Consistent with decreased endocytosis of these receptors, PS1 mutant mice have elevated levels of apolipoprotein E in the brain. Thus, these data demonstrate a functional link between two major genetic factors that cause early-onset and late-onset Alzheimer's disease.
G-Protein-Coupled Receptor Screen Reveals a Role for Chemokine Receptor CCR5 in Suppressing Microglial Neurotoxicity
Authors: Gamo Kazushige , Kiryu-Seo Sumiko , Konishi Hiroyuki , Aoki Shunsuke , Matsushima Kouji , Wada Keiji , Kiyama Hiroshi
Published: November 2008

G-protein-coupled receptors (GPCRs) form the largest superfamily of membrane proteins, and several GPCRs have been implicated in signaling between neurons and glia to protect neurons from pathological stresses. Here, we have used a screening strategy to investigate GPCRs that are involved in neuronal protection. The real-time PCR was performed using 274 primers targeting nonsensory GPCR mRNAs, which were listed on the database. The cDNAs from control and nerve-injured hypoglossal nuclei of mouse brain were used, and the alterations of PCR products were compared. This screen and the subsequentin situhybridization screen exhibited six GPCR mRNAs which were prominently and convincingly induced in nerve-injured hypoglossal nuclei. Among these candidates, the chemokine receptor CCR5 was selected, based on the marked induction in CCR5 mRNA in microglia after nerve injury. The mRNA expression of ligands for CCR5, such as regulated on activation normal T-cell expressed and secreted (RANTES/CCL5), MIP-1α, and MIP-1β, were induced in injured motor neurons, indicating that CCR5 and its ligands were expressed in microglia and neurons, respectively, in response to nerve injury.In vitro, lipopolysaccharide (LPS)-induced expression of mRNAs for inflammatory cytokines (IL-1β, IL-6, and tumor necrosis factor-α) and inducible nitric oxide synthase (iNOS) in microglia were all suppressed by RANTES. Those suppressions were not observed in microglia from CCR5 null mice. In addition, nerve injury-induced motor neuron death seen in wild type C56BL/6J mice was accelerated in CCR5 knock-out C57BL/6J. These results may suggest that CCR5-mediated neuron–glia signaling functions to protect neurons by suppressing microglia toxicity.
Compensatory Rapid Switching of Binasal Inputs in the Olfactory Cortex
Authors: Kikuta Shu , Kashiwadani Hideki , Mori Kensaku
Published: November 2008

Odors are inhaled through the nostrils into two segregated nasal passages and detected by sensory neurons in the bilateral olfactory epithelia. Airflow through the two nasal passages is usually asymmetrical because of alternating changes in nasal mucosal congestion. Here we show that neurons in the anterior olfactory nucleus (AON) of the adult rat olfactory cortex are ordinarily dominated by ipsi-nasal inputs and that binasal neurons in the AON respond to ipsilateral and contralateral nasal inputs with nearly equivalent odorant category selectivity. Deprivation of ipsilateral nasal inputs by unilateral nostril obstruction greatly enhanced the response to contralateral odor stimulation, in a reversible manner, in ∼33% of AON neurons within only several minutes. In 27% of AON neurons that showed spike responses induced by the inspiration of room air, ipsilateral nasal obstruction initially suppressed respiration phase-locked spike discharges and, several minutes later, induced respiration phase-locked discharges with longer delays between inspiration and response. Recordings from AON neurons in rats with anterior commissure (AC) transection indicated that the resumed respiration phase-locked discharges with longer delays were mediated by the contralateral pathway via the AC. The ipsi-nasal occlusion-induced switching of nasal inputs to individual AON neurons shows that a subset of AON neurons in the adult rat has neuronal mechanisms for rapid nostril dominance plasticity, which may enable both right and left olfactory cortices to preserve their responsiveness to the external odor world, despite reciprocal changes in nasal airflow.
Maladaptive Homeostatic Plasticity in a Rodent Model of Central Pain Syndrome: Thalamic Hyperexcitability after Spinothalamic Tract Lesions
Authors: Wang Gexin , Thompson Scott M.
Published: November 2008

Central pain syndrome (CPS) is defined as pain associated with a lesion of the CNS and is a common consequence of spinal cord injuries. We generated a rodent model of CPS by making unilateral electrolytic or demyelinating lesions centered on the spinothalamic tract in rats. Thermal hyperalgesia and mechanical allodynia occurred in both hind paws and forepaws by 7 d postlesion and were maintained >31 d. Field potentials in the ventral posterior lateral nucleus (VPL) in thalamic brain slices from lesioned animals displayed an increased probability of burst responses. Ethosuximide, a T-type calcium channel blocker, eliminated busting in lesioned thalamic slices and attenuated lesion-induced hyperalgesia and allodynia. We conclude that CPS in this model results from an increase in the excitability of thalamic nuclei that have lost normal ascending inputs as the result of a spinal cord injury and suggest that ethosuximide will relieve human CPS by restoring normal thalamic excitability.
Crucial Role of CB2Cannabinoid Receptor in the Regulation of Central Immune Responses during Neuropathic Pain
Authors: Racz Ildiko , Nadal Xavier , Alferink Judith , Baños Josep E. , Rehnelt Jennifer , Martín Miquel , Pintado Belén , Gutierrez-Adan Alfonso , Sanguino Elena , Manzanares Jorge , Zimmer Andreas , Maldonado Rafael
Published: November 2008

Neuropathic pain is a clinical manifestation of nerve injury difficult to treat even with potent analgesic compounds. Here, we used different lines of genetically modified mice to clarify the role played by CB2cannabinoid receptors in the regulation of the central immune responses leading to the development of neuropathic pain. CB2knock-out mice and wild-type littermates were exposed to sciatic nerve injury, and both genotypes developed a similar hyperalgesia and allodynia in the ipsilateral paw. Most strikingly, knock-outs also developed a contralateral mirror image pain, associated with an enhanced microglial and astrocytic expression in the contralateral spinal horn. In agreement, hyperalgesia, allodynia, and microglial and astrocytic activation induced by sciatic nerve injury were attenuated in transgenic mice overexpressing CB2receptors. These results demonstrate the crucial role of CB2cannabinoid receptor in modulating glial activation in response to nerve injury. The enhanced manifestations of neuropathic pain were replicated in irradiated wild-type mice reconstituted with bone marrow cells from CB2knock-outs, thus demonstrating the implication of the CB2receptor expressed in hematopoietic cells in the development of neuropathic pain at the spinal cord.
Interferon-γ Is a Critical Modulator of CB2Cannabinoid Receptor Signaling during Neuropathic Pain
Authors: Racz Ildiko , Nadal Xavier , Alferink Judith , Baños Josep E. , Rehnelt Jennifer , Martín Miquel , Pintado Belén , Gutierrez-Adan Alfonso , Sanguino Elena , Bellora Nicolas , Manzanares Jorge , Zimmer Andreas , Maldonado Rafael
Published: November 2008

Nerve injuries often lead to neuropathic pain syndrome. The mechanisms contributing to this syndrome involve local inflammatory responses, activation of glia cells, and changes in the plasticity of neuronal nociceptive pathways. Cannabinoid CB2receptors contribute to the local containment of neuropathic pain by modulating glial activation in response to nerve injury. Thus, neuropathic pain spreads in mice lacking CB2receptors beyond the site of nerve injury. To further investigate the mechanisms leading to the enhanced manifestation of neuropathic pain, we have established expression profiles of spinal cord tissues from wild-type and CB2-deficient mice after nerve injury. An enhanced interferon-γ (IFN-γ) response was revealed in the absence of CB2signaling. Immunofluorescence stainings demonstrated an IFN-γ production by astrocytes and neurons ispilateral to the nerve injury in wild-type animals. In contrast, CB2-deficient mice showed neuronal and astrocytic IFN-γ immunoreactivity also in the contralateral region, thus matching the pattern of nociceptive hypersensitivity in these animals. Experiments in BV-2 microglia cells revealed that transcriptional changes induced by IFN-γ in two key elements for neuropathic pain development, iNOS (inducible nitric oxide synthase) and CCR2, are modulated by CB2receptor signaling. The most direct support for a functional involvement of IFN-γ as a mediator of CB2signaling was obtained with a double knock-out mouse strain deficient in CB2receptors and IFN-γ. These animals no longer show the enhanced manifestations of neuropathic pain observed in CB2knock-outs. These data clearly demonstrate that the CB2receptor-mediated control of neuropathic pain is IFN-γ dependent.
Differential Contributions of Prefrontal and Hippocampal Dopamine D1and D2Receptors in Human Cognitive Functions
Authors: Takahashi Hidehiko , Kato Motoichiro , Takano Harumasa , Arakawa Ryosuke , Okumura Masaki , Otsuka Tatsui , Kodaka Fumitoshi , Hayashi Mika , Okubo Yoshiro , Ito Hiroshi , Suhara Tetsuya
Published: November 2008

Dopamine D1receptors in the prefrontal cortex (PFC) are important for prefrontal functions, and it is suggested that stimulation of prefrontal D1receptors induces an inverted U-shaped response, such that too little or too much D1receptor stimulation impairs prefrontal functions. Less is known of the role of D2receptors in cognition, but previous studies showed that D2receptors in the hippocampus (HPC) might play some roles via HPC–PFC interactions. We measured both D1and D2receptors in PFC and HPC using positron emission tomography in healthy subjects, with the aim of elucidating how regional D1and D2receptors are differentially involved in frontal lobe functions and memory. We found an inverted U-shaped relation between prefrontal D1receptor binding and Wisconsin Card Sorting Test performance. However, prefrontal D2binding has no relation with any neuropsychological measures. Hippocampal D2receptor binding showed positive linear correlations not only with memory function but also with frontal lobe functions, but hippocampal D1receptor binding had no association with any memory and prefrontal functions. Hippocampal D2receptors seem to contribute to local hippocampal functions (long-term memory) and to modulation of brain functions outside HPC (“frontal lobe functions”), which are mainly subserved by PFC, via the HPC–PFC pathway. Our findings suggest that orchestration of prefrontal D1receptors and hippocampal D2receptors might be necessary for human executive function including working memory.
Habenula: Crossroad between the Basal Ganglia and the Limbic System
Authors: Hikosaka Okihide , Sesack Susan R. , Lecourtier Lucas , Shepard Paul D.
Published: November 2008

There is a growing awareness that emotion, motivation, and reward values are important determinants of our behavior. The habenula is uniquely positioned both anatomically and functionally to participate in the circuit mediating some forms of emotive decision making. In the last few years there has been a surge of interest in this structure, especially the lateral habenula (LHb). The new studies suggest that the LHb plays a pivotal role in controlling motor and cognitive behaviors by influencing the activity of dopamine and serotonin neurons. Further, dysfunctions of the LHb have also been implicated in psychiatric disorders, such as depression, schizophrenia, and drug-induced psychosis.
Two-Photon Imaging during Prolonged Middle Cerebral Artery Occlusion in Mice Reveals Recovery of Dendritic Structure after Reperfusion
Authors: Li Ping , Murphy Timothy H.
Published: November 2008

Filament occlusion of the middle cerebral artery (MCA) is a well accepted animal model of focal ischemia. Advantages of the model are relatively long occlusion times and a large penumbra region that simulates aspects of human stroke. Here, we use two-photon and confocal microscopy in combination with regional measurement of blood flow using laser speckle to assess the spatial relationship between the borders of the MCA ischemic territory and loss of dendrite structure, as well as the effect of reperfusion on dendritic damage in adult YFP (yellow fluorescent protein) and GFP (green fluorescent protein) C57BL/6 transgenic mice with fluorescent (predominantly layer 5) neurons. By examining the spatial extent of dendritic damage, we determined that 60 min of MCA occlusion produced a core with severe structural damage that did not recover after reperfusion (begins ∼3.8 mm lateral to midline), a reversibly damaged area up to 0.6 mm medial to the core that recovered after reperfusion (penumbra), and a relatively structurally intact area (∼1 mm wide; medial penumbra) with hypoperfusion. Loss of structure was preceded by a single ischemic depolarization 122.1 ± 10.2 s after occlusion onset. Reperfusion of animals after 60 min of ischemia was not associated with exacerbation of damage (reperfusion injury) and resulted in a significant restoration of blebbed dendritic structure, but only within ∼0.6 mm lateral of the dendritic damage structural border. In summary, we find that recovery of dendritic structure can occur after reperfusion after even 60 min of ischemia, but is likely restricted to a relatively small penumbra region with partial blood flow or oxygenation.
Molecular Correlates of Laminar Differences in the Macaque Dorsal Lateral Geniculate Nucleus
Authors: Murray Karl D. , Rubin Carol M. , Jones Edward G. , Chalupa Leo M.
Published: November 2008

In anthropoid primates, cells in the magnocellular and parvocellular layers of the dorsal lateral geniculate nucleus (dLGN) are distinguished by unique retinal inputs, receptive field properties, and laminar terminations of their axons in visual cortex. To identify genes underlying these phenotypic differences, we screened RNA from magnocellular and parvocellular layers of adult macaque dLGN for layer-specific differences in gene expression. Real-time quantitative reverse transcription-PCR andin situhybridization were used to confirm gene expression in adult and fetal macaque. Cellular localization of gene expression revealed 11 new layer-specific markers, of which 10 were enriched in magnocellular layers (BRD4,CAV1,EEF1A2,FAM108A1,INα,KCNA1,NEFH,NEFL,PPP2R2C, andSFRP2) and one was enriched in parvocellular and koniocellular layers (TCF7L2). These markers relate to functions involved in development, transcription, and cell signaling, with Wnt/β-catenin and neurofilament pathways figuring prominently. A subset of markers was differentially expressed in the fetal dLGN during a developmental epoch critical for magnocellular and parvocellular pathway formation. These results provide new evidence for the molecular differentiation of magnocellular and parvocellular streams through the primate dLGN.
Adaptation of Firing Rate and Spike-Timing Precision in the Avian Cochlear Nucleus
Authors: Kuznetsova Marina S. , Higgs Matthew H. , Spain William J.
Published: November 2008

Adaptation is commonly defined as a decrease in response to a constant stimulus. In the auditory system such adaptation is seen at multiple levels. However, the first-order central neurons of the interaural time difference detection circuit encode information in the timing of spikes rather than the overall firing rate. We investigated adaptation duringin vitrowhole-cell recordings from chick nucleus magnocellularis neurons. Injection of noisy, depolarizing current caused an increase in firing rate and a decrease in spike time precision that developed over ∼20 s. This adaptation depends on sustained depolarization, is independent of firing, and is eliminated by α-dendrotoxin (0.1 μm), implicating slow inactivation of low-threshold voltage-activated K+channels as its mechanism. This process may alter both firing rate and spike-timing precision of phase-locked inputs to coincidence detector neurons in nucleus laminaris and thereby adjust the precision of sound localization.
Modes and Mishaps of Neuronal Migration in the Mammalian Brain
Authors: Métin Christine , Vallee Richard B. , Rakic Pasko , Bhide Pradeep G.
Published: November 2008

The ability of neurons to migrate to their appropriate positions in the developing brain is critical to brain architecture and function. Recent research has elucidated different modes of neuronal migration and the involvement of a host of signaling factors in orchestrating the migration, as well as vulnerabilities of this process to environmental and genetic factors. Here we discuss the role of cytoskeleton, motor proteins, and mechanisms of nuclear translocation in radial and tangential migration of neurons. We will also discuss how these and other events essential for normal migration of neurons can be disrupted by genetic and environmental factors that contribute to neurological disease in humans.
The Immediate Early GeneArc/Arg3.1: Regulation, Mechanisms, and Function
Authors: Bramham Clive R. , Worley Paul F. , Moore Melissa J. , Guzowski John F.
Published: November 2008

In a manner unique among activity-regulated immediate early genes (IEGs), mRNA encoded byArc(also known asArg3.1) undergoes rapid transport to dendrites and local synaptic translation. Despite this intrinsic appeal, relatively little is known about the neuronal and behavioral functions of Arc or its molecular mechanisms of action. Here, we attempt to distill recent advances on Arc spanning its transcriptional and translational regulation, the functions of the Arc protein in multiple forms of neuronal plasticity [long-term potentiation (LTP), long-term depression (LTD), and homeostatic plasticity], and its broader role in neural networks of behaving animals. Worley and colleagues have shown that Arc interacts with endophilin and dynamin, creating a postsynaptic trafficking endosome that selectively modifies the expression of AMPA-type glutamate receptors at the excitatory synapses. Both LTD and homeostatic plasticity in the hippocampus are critically dependent on Arc-mediated endocytosis of AMPA receptors. LTD evoked by activation of metabotropic glutamate receptors depends on rapidArctranslation controlled by elongation factor 2. Bramham and colleagues have shown that sustained translation of newly induced Arc mRNA is necessary for cofilin phosphorylation and stable expansion of the F-actin cytoskeleton underlying LTP consolidation in the dentate gyrus of live rats. In addition to regulating F-actin, Arc synthesis maintains the activity of key translation factors during LTP consolidation. This process of Arc-dependent consolidation is activated by the secretory neurotrophin, BDNF. Moore and colleagues have shown that Arc mRNA is a natural target for nonsense-mediated mRNA decay (NMD) by virtue of its two conserved 3′-UTR introns. NMD and other related translation-dependent mRNA decay mechanisms may serve as critical brakes on protein expression that contribute to the fine spatial-temporal control of Arc synthesis. In studies in behaving rats, Guzowski and colleagues have shown that location-specific firing of CA3 and CA1 hippocampal neurons in the presence of theta rhythm provides the necessary stimuli for activation ofArctranscription. The impact ofArctranscription in memory processes may depend on the specific context of coexpressed IEGs, in addition to posttranscriptional regulation of Arc by neuromodulatory inputs from the amygdala and other brain regions. In sum, Arc is emerging as a versatile, finely tuned system capable of coupling changes in neuronal activity patterns to diverse forms of synaptic plasticity, thereby optimizing information storage in active networks.
Next Generation Mobile Internet – Network and Service PlatformDie nächste Generation des mobilen Internet – Netz- und Serviceplattform
Authors: Kellerer Wolfgang , Widmer Jörg , Berndt Hendrik
Published: November 2008

The Internet has become the main network technology supporting communications and Web services in all areas of our society. In order to perform this role efficiently, a fundamental redesign of the Internet architecture is being discussed. In particular, mobile devices and wireless access networks will constitute an important part of the Internet infrastructure. Based on a general discussion of requirements, this article focuses on the challenges of a next generation mobile Internet and discusses research approaches for mobility, addressing, heterogeneous access, and service platforms.
Spontaneous Virtual Networks: On the Road Towards the Internet´s Next GenerationSpontane Virtuelle Netze: Auf dem Weg zur nächsten Generation des Internets
Authors: Waldhorst Oliver P. , Blankenhorn Christian , Haage Dirk , Holz Ralph , Koch Gerald G , Koldehofe Boris , Lampi Fleming , Mayer Christoph P. , Mies Sebastian
Published: November 2008

Novel Internet applications demand global availability of complex services that can adapt dynamically to application requirements. At the same time, pervasive Internet usage and heterogeneous access technologies impose new challenges for service deployment. We present Spontaneous Virtual Networks (SpoVNet), a methodology that enables easy development of new services with transparent support for mobility, multi-homing, and heterogeneous environments. This article presents the overlay-based architecture of SpoVNet that supports the spontaneous deployment of new services as well as a seamless transition towards future networks. SpoVNet´s architecture offers support for the underlay aware adaptation of overlays by the use of cross-layer information. In the context of two exemplary services like a group communication service and an event service as well as two demanding applications – a realtime online game and a video streaming application – we illustrate how SpoVNet is of value in establishing services and applications for the Next Generation Internet.
The Social Significance of Barack Obama
Authors: Hartmann Doug
Published: November 2008

This summer, Contexts convened a panel of esteemed sociologists at contexts.org and asked them to discuss the social significance of Barack Obama's campaign for President of the United States and what it might mean, sociologically speaking, were he to win the office.
Clouds and Rain
Authors: Olson Todd
Published: November 2008

In the Florentine Codex, an indigenous tlacuilo (painter-scribe) of sixteenth-century New Spain responded to imported European visual technologies by dissociating form from material requirements.
The Social and Its Forms
Authors: Vernon James
Published: November 2008

Thoughts on the relationship between form and the social.
On Forms and Media
Authors: Henkin David M.
Published: November 2008

Reflections on the relationship between forms and media. Recent interest in the history of media presents new occasions for interdisciplinary thinking about form.
A Fugitive Book
Authors: Hesse Carla
Published: November 2008

This essay describes a virtually unknown French revolutionary edition of Rousseau's Social Contract and reconstructs the trajectory of its appearance, disappearance, and reappearance. The purpose of the essay is to show that formal analysis and narrative are inseparable in the act of interpretation and that neither mode of interpretation can escape the historicity of the object.
Form in Ashes
Authors: Laqueur Thomas
Published: November 2008

This essay explains the advent of modern cremation by how it came to stand in a variety of isomorphic relationships with other cultural practices or political positions. The meanings of this form of disposing of the dead—of rendering corpses quickly into their component parts through combustion in technologically advanced furnaces—are a consequence of the ways this relationship was articulated.
The association of serum adipocyte fatty acid-binding protein with coronary artery disease in Korean adults
Authors: Rhee E J , Lee W Y , Park C Y , Oh K W , Kim B J , Sung K C , Kim B S
Published: November 2008

Objectives

Adipocyte fatty acid-binding protein (A-FABP), also known as aP2 or FABP4, is abundantly expressed in adipocytes and plays a role in glucose homeostasis. We analyzed the relationship between the coronary artery disease and serum FABP4 levels in Korean adults.

Methods

In a total of 234 Korean adults, in whom coronary angiograms were performed, anthropometric measurements were done and fasting glucose and lipid profiles were measured. Serum FABP4 levels were measured using ELISA. The presence of metabolic syndrome was diagnosed according to American Heart Association/National Heart, Lung and Blood Institute (AHA/NHBL) criteria with body mass index (BMI) substituted for waist circumference.

Results

Among the subjects, 31.6% had diabetes, 46.9% had metabolic syndrome, and mean log (FABP4) levels showed significantly higher levels in subjects with diabetes. Among the subjects, 42.4% had normal coronary vessel, 34.6% had 1-vessel disease, 13.7% had 2-vessel disease, and 9.4% had 3-vessel disease. Among the parameters, mean age, fasting glucose, and log (FABP4) levels increased significantly as the numbers of stenotic vessel increased from normal to 3-vessel disease, and for FABP4, these significances showed a consistent trend for difference after adjustment for age, gender, BMI, and fasting glucose (P=0.072). Mean log (FABP4) level showed lower values in subjects taking aspirin, and higher values in subjects taking statin and anti-hypertensive drugs.

Conclusions

Serum FABP4 levels increased as the numbers of stenotic coronary artery increased, although these differences were attenuated after adjustment for age and fasting glucose levels. Various anti-atherogenic medications showed different effects on the serum FABP4 levels, which need further investigation.
Armazenamento de botões florais para produção de sementes de abóbora com polinização manual
Authors: Salata Ariane da Cunha , Bertolini Erick Vinicius , Cardoso Antonio Ismael Inácio
Published: November 2008

O objetivo deste trabalho foi verificar a influência do armazenamento de botões florais masculinos por diferentes períodos, na produção e qualidade de sementes de abóbora cultivar Piramoita. O experimento foi desenvolvido no período de agosto a dezembro de 2005. O delineamento experimental utilizado foi em blocos ao acaso, com quatro repetições e cinco tratamentos: polinização manual com flor aberta no dia (zero dia de armazenamento) e polinização manual com botões armazenados em geladeira (7 ºC) por 1, 2, 3 e 4 dias. Quanto maior o período de armazenamento dos botões florais masculinos, menor a produção (número e massa) de sementes por fruto e a massa média do fruto. Também há uma perda de vigor e germinação das sementes quando se aumenta o período de armazenamento dos botões florais, reduzindo sua qualidade.
Estabilidade de produção de híbridos simples e duplos de milho oriundos de um mesmo conjunto gênico
Authors: Machado Juarez Campolina , Souza João Cândido de , Ramalho Magno Antonio Patto , Lima José Luís
Published: November 2008

O presente trabalho foi realizado com o objetivo de comparar a estabilidade de híbridos simples e híbridos duplos de milho oriundos de um mesmo conjunto gênico. Foram avaliados 55 tratamentos, sendo dez híbridos simples comerciais, utilizados como parentais e 45 híbridos duplos resultantes de um dialelo completo. As sementes dos híbridos duplos foram obtidas na área experimental do Departamento de Biologia da Universidade Federal de Lavras (DBI/UFLA). Os experimentos foram desenvolvidos em 15 ambientes, no ano agrícola de 2005/2006, em propriedades de agricultores e estações experimentais. O delineamento experimental utilizado foi o de blocos casualizados com três repetições e o caráter avaliado foi a produtividade de espigas despalhadas (kg ha-1), corrigida para 13% de umidade. Obteve-se a contribuição de cada híbrido para a interação genótipos x ambientes e o desvio em relação ao desempenho máximo em cada ambiente utilizando a estatística não-paramétrica por meio da soma de postos. Os híbridos duplos foram, em média, mais estáveis, contudo, identificaram-se híbridos simples tão estáveis quanto os duplos.
Capacidade combinatória, divergência genética entre linhagens de milho e correlação com heterose
Authors: Paterniani Maria Elisa Ayres Guidetti Zagatto , Guimarães Paula de Souza , Lüders Reginaldo Roberto , Gallo Paulo Boller , Souza Anete Pereira de , Laborda Prianda Rios , Oliveira Karine Miranda
Published: November 2008

Objetivou-se avaliar o desempenho de híbridos simples de milho (Zea mays L.), obtidos de cruzamentos dialélicos entre linhagens divergentes, estimar a capacidade de combinação das linhagens e verificar se a divergência genética entre as linhagens, obtida por marcadores moleculares, é correlacionada com a heterose dos híbridos simples no campo. Trinta e seis híbridos resultantes de um dialelo parcial foram avaliados em Campinas e em Mococa e as 12 linhagens parentais somente em Campinas, a fim de se calcular a heterose dos híbridos. O delineamento experimental empregado foi o de blocos ao acaso, com três repetições e 2 testemunhas comerciais. Avaliaram-se os caracteres: altura da planta (AP), altura da espiga (AE) e massa de grãos (MG). Análises de variância foram efetuadas, sendo as médias comparadas entre si pelo teste de Tukey a 5%. A capacidade de combinação das linhagens foi obtida de acordo com o método de Geraldi e Miranda Filho. Estimaram-se as correlações entre heterose, produtividade e capacidade específica de combinação com divergência genética obtida por AFLP e SSR. Destacou-se o híbrido PM624 x IP398, e as linhagens VER266 e L105 revelaram efeitos positivos da capacidade de combinação para produtividade. As estimativas de heterose variaram de -559 a 6.320 kg ha-1. Não houve correlação entre heterose, capacidade específica de combinação e produtividade dos híbridos com a distância genética por AFLP e SSR, indicando que não é possível fazer inferências sobre o comportamento dos híbridos de milho a partir da divergência genética entre as linhagens parentais.
Agronomic performance of sugarcane families in response to water stress
Authors: Silva Marcelo de Almeida , Soares Rogério Augusto Bremm , Landell Marcos Guimarães de Andrade , Campana Mário Pércio
Published: November 2008

Water deficit is one of the major factors limiting the production of sugarcane, especially in areas where there is a prolonged period of water deficiency, such as the West Central Brazilian region. One way to overcome this problem is to cultivate resistant or tolerant varieties. An experiment was set up at the Jalles Machado Sugar Mill, located near Goianésia, Goiás State, Brazil, to evaluate agronomic performance of several sugarcane families. A comparative analysis was carried out among the families under two irrigation regimes, one under regular environmental conditions and another under monthly irrigations during the period of water deficiency. Evaluated families consisted of 25 progenies planted in a factorial design with three replications with 20 plants each. The first ratoon crop was evaluated for four yield components, stalk height, stalk diameter, stalk number and Brix. By analysis of variance, stalk number and stalk height were influenced by water stress conditions during the initial growth phase, and for stalk diameter and Brix, water regime had no effect on the average expression of the characters during the growth phase. The method of classification in four categories proved to be adequate. Some families had high values for stalk diameter, stalk number and stalk height under water stress conditions. This study showed that it is possible to select sugarcane families under water deficit conditions associated with higher stalk diameter, stalk number and stalk height.
Fenologia da goiabeira 'Paluma' sob diferentes sistemas de cultivos, épocas e intensidades de poda de frutificação
Authors: Serrano Luiz Augusto Lopes , Marinho Cláudia Sales , Lima Inorbert de Melo , Martins Marlon Vagner Valentim , Ronchi Cláudio Pagotto , Tardin Flávio Dessaune
Published: November 2008

O trabalho teve como objetivo avaliar os efeitos de diferentes épocas e intensidades de poda de frutificação sobre a fenologia da goiabeira 'Paluma', em dois sistemas de cultivo, em Pedro Canário (ES). O delineamento experimental foi o de blocos ao acaso, em esquema de parcelas sub-subdivididas. As parcelas foram os sistemas de cultivo irrigado e sequeiro; as subparcelas foram as épocas de poda (10/11/2005, 9/12/2005, 13/1/2006 e 10/2/2006); e as sub-subparcelas foram as intensidades de poda (curta, média e longa). O ciclo da goiabeira 'Paluma', entre a poda até o início da colheita dos frutos, variou de 182 (poda em novembro e dezembro) a 203 dias (poda em fevereiro). A queda fisiológica dos frutos ocorreu até os 56 dias após o final do florescimento. A irrigação e a poda longa proporcionaram maior brotação e estabelecimento dos ramos. As plantas submetidas à poda longa em fevereiro produziram maior número de frutos por ramo. Independentemente da época de poda, as plantas submetidas à poda curta apresentaram menor número de frutos por ramo e menor índice de pegamento de frutos. A irrigação e as podas realizadas em dezembro e janeiro favoreceram a produção de frutos maiores.
Acúmulo de silício em plantas de arroz do ecossistema de várzea submetido à aplicação de diferentes fontes
Authors: Ramos Lucélia Alves , Korndörfer Gaspar Henrique , Nolla Antonio
Published: November 2008

A baixa produtividade brasileira de arroz decorre, principalmente, da reduzida fertilidade do solo e alta suscetibilidade a algumas doenças. A adubação com silício pode ser uma alternativa no sentido de amenizar, sobretudo, o impacto das doenças sobre a produtividade. No intuito de identificar fontes eficientes quanto ao fornecimento de Si para a cultura do arroz, foi instalado um experimento em vasos, utilizando-se Neossolo Quartzarênico Órtico típico, em delineamento em blocos casualizados. As fontes de Si utilizadas foram siligran e silicon, nas formas granulada e pó, na dose de 200 mg kg-1 de Si. A curva de resposta a Si foi estabelecida pela aplicação de uma fonte-padrão (Wollastonita) nas doses de 0, 50, 100, 200, 400 mg kg-1 de Si, visando obter uma curva de resposta. Após a semeadura da cultivar de arroz Rio Formoso, avaliou-se a produção de massa seca da parte aérea, massa de panículas, produção de grãos, Si acumulado na planta e teores de Si no solo. A fonte-padrão Wollastonita apresentou comportamento linear, aumentando o Si disponível no solo e a absorção pelo arroz com o aumento das doses aplicadas. Os maiores aumentos, nos teores de Si na parte aérea, casca, Si acumulado e na massa seca total foram proporcionados pela Wollastonita. A fonte que proporcionou maior aumento na produtividade de grãos foi silicon na forma de pó. O extrator ácido acético extraiu maiores quantidade de Si do solo em relação ao cloreto de cálcio, superestimando os resultados.
Tempo de estratificação e temperatura na porcentagem e velocidade de germinação do marmeleiro 'Japonês'
Authors: Pio Rafael , Abucarma Vânia Márcia , Höring Carla Franciele , Chagas Edvan Alves , Barbosa Wilson
Published: November 2008

Os marmeleiros sempre foram propagados comercialmente através de enraizamento de estacas. Devido à falta de vigor das mudas, principalmente nos primeiros anos após o plantio, uma série de trabalhos foi desenvolvida no Brasil a fim de viabilizar a utilização do marmeleiro 'Japonês' como porta-enxerto para marmelos. No entanto, ainda algumas metodologias, na fase de produção desses porta-enxertos, necessitam de investigação para preconizar o sistema de produção de mudas. Assim, realizou-se esse trabalho com o intuito de determinar o tempo ideal de estratificação e o efeito da temperatura na porcentagem e velocidade de germinação do marmeleiro 'Japonês'. Sementes foram colocadas em placas de Petri, entre camadas de algodão umedecido e submetidas a diferentes tempos de estratificação (0, 15 e 30 dias), em câmara tipo B.O.D., a 4º C de temperatura e, posteriormente, semeadas em bandejas plásticas contendo areia autoclavada como substrato (120 º C por 20 minutos), em câmara tipo B.O.D., sob diferentes temperaturas (15, 20, 25 e 30 ºC). As contagens das plântulas normais foram realizadas diariamente, por 30 dias e no fim calculou-se o índice de velocidade de germinação (IVG) e a porcentagem de germinação. Concluiu-se que as sementes do marmeleiro 'Japonês' devem ser estratificadas por 30 dias a frio e semeadas quando as temperaturas externas estiverem entre 15 e 20 ºC para se obter máxima germinação das sementes.