bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic changes in Rap1 activity are required for cell retraction and spreading during mitosis
Authors: Dao Vi Thuy , Dupuy Aurélien Guy , Gavet Olivier , Caron Emmanuelle , de Gunzburg Jean
Published: July 2009

At the onset of mitosis, most adherent cells undergo cell retraction characterised by the disassembly of focal adhesions and actin stress fibres. Mitosis takes place in rounded cells, and the two daughter cells spread again after cytokinesis. Because of the well-documented ability of the small GTPase Rap1 to stimulate integrin-dependent adhesion and spreading, we assessed its role during mitosis. We show that Rap1 activity is regulated during this process. Changes in Rap1 activity play an essential role in regulating cell retraction and spreading, respectively, before and after mitosis of HeLa cells. Indeed, endogenous Rap1 is inhibited at the onset of mitosis; conversely, constitutive activation of Rap1 inhibits the disassembly of premitotic focal adhesions and of the actin cytoskeleton, leading to delayed mitosis and to cytokinesis defects. Rap1 activity slowly increases after mitosis ends; inhibition of Rap1 activation by the ectopic expression of the dominant-negative Rap1[S17A] mutant prevents the rounded cells from spreading after mitosis. For the first time, we provide evidence for the direct regulation of adhesion processes during mitosis via the activity of the Rap1 GTPase.
Transient assembly of F-actin by phagosomes delays phagosome fusion with lysosomes in cargo-overloaded macrophages
Authors: Liebl David , Griffiths Gareth
Published: July 2009

Dynamic remodelling of the cortical actin cytoskeleton is required for phagocytic uptake of pathogens and other particles by macrophages. Actin can also be nucleated de novo on membranes of nascent phagosomes, a process that can stimulate or inhibit phagosome fusion with lysosomes. Recently, phagosomes were shown to polymerize actin in transient pulses, called actin `flashing', whose function remains unexplained. Here, we investigated phagosomal actin dynamics in live macrophages expressing actin tagged with green fluorescent protein (GFP). We show that only immature phagosomes can transiently induce assembly of actin coat, which forms a barrier preventing phagosome-lysosome docking and fusion. The capacity of phagosomes to assemble actin is enhanced in cells exposed to increased phagocytic load, which also exhibit a delay in phagosome maturation. Parallel analysis indicated that polymerization of actin on macropinosomes also induces compression and propulsion. We show that dynamic interactions between membrane elastic tension and compression forces of polymerizing actin can also lead to macropinosome constriction and scission – a process that is obstructed on rigid phagosomes. We hypothesize that the rate of individual phagosome maturation, as well as the biogenesis and remodelling of macropinosomes, can be regulated by the extent and manner of actin assembly on their membrane.
KDP-1 is a nuclear envelope KASH protein required for cell-cycle progression
Authors: McGee Matthew D. , Stagljar Igor , Starr Daniel A.
Published: July 2009

Klarsicht, ANC-1 and Syne homology (KASH) proteins localize to the outer nuclear membrane where they connect the nucleus to the cytoskeleton. KASH proteins interact with Sad1-UNC-84 (SUN) proteins to transfer forces across the nuclear envelope to position nuclei or move chromosomes. A new KASH protein, KDP-1, was identified in a membrane yeast two-hybrid screen of a Caenorhabditis elegans library using the SUN protein UNC-84 as bait. KDP-1 also interacted with SUN-1. KDP-1 was enriched at the nuclear envelope in a variety of tissues and required SUN-1 for nuclear envelope localization in the germline. Genetic analyses showed that kdp-1 was essential for embryonic viability, larval growth and germline development. kdp-1(RNAi) delayed the entry into mitosis in embryos, led to a small mitotic zone in the germline, and caused an endomitotic phenotype. Aspects of these phenotypes were similar to those seen in sun-1(RNAi), suggesting that KDP-1 functions with SUN-1 in the germline and early embryo. The data suggest that KDP-1 is a novel KASH protein that functions to ensure the timely progression of the cell cycle between the end of S phase and the entry into mitosis.
Thyrotoxic periodic paralysis due to excessive L-thyroxine replacement in a Caucasian man
Authors: Hannon M J , Behan L A , Agha A
Published: July 2009

Thyrotoxic periodic paralysis is a potentially fatal complication of hyperthyroidism, more common in Asian races, which is defined by a massive intracellular flux of potassium. This leads to profound hypokalaemia and muscle paralysis. Although the paralysis is temporary, it may be lethal if not diagnosed and treated rapidly, as profound hypokalaemia may induce respiratory muscle paralysis or cardiac arrest. The condition is often misdiagnosed in the west due to its comparative rarity in Caucasians; however it is now increasingly described in Caucasians and is also being seen with increasing frequency in western hospitals due to increasing immigration and population mobility. Here we describe the case of a patient with panhypopituitarism due to a craniopharyngioma, who developed thyrotoxic periodic paralysis due to excessive L-thyroxine replacement. This disorder has been described in Asian subjects but, to our knowledge, thyrotoxic periodic paralysis secondary to excessive L-thyroxine replacement has never been described in Caucasians.
Partially Observable Markov Decision Processes: A Geometric Technique and Analysis
Authors: Zhang Hao
Published: July 2009

This paper presents a novel framework for studying partially observable Markov decision processes (POMDPs) with finite state, action, observation sets, and discounted rewards. The new framework is solely based on future-reward vectors associated with future policies, which is more parsimonious than the traditional framework based on belief vectors. It reveals the connection between the POMDP problem and two computational geometry problems, i.e., finding the vertices of a convex hull and finding the Minkowski sum of convex polytopes, which can help solve the POMDP problem more efficiently. The new framework can clarify some existing algorithms over both finite and infinite horizons and shed new light on them. It also facilitates the comparison of POMDPs with respect to their degree of observability, as a useful structural result.
Technology, Organization, and Structure—A Morphogenetic Approach
Authors: Mutch Alistair
Published: July 2009

This article relates Archer's morphogenetic approach, derived from the philosophical tradition of critical realism, to the use of information and communication technology in organizations. Three gains are seen to accrue from this approach: greater clarity about the material properties of technology, links to broader structural conditions arising from the conceptualization of the relationship between agency and structure, and the potential to explore the importance of reflexivity in contemporary organizations, especially in conditions of the widespread use of information and communication technology. The importance of disaggregating the artifacts of this technology into levels and features is stressed to enable analysis to explore the specific impacts of particular combinations. This is developed through a discussion of data warehousing in connection with the attention being given to the importance of analytics in organizational strategies. Key features are in wider aspects of the cultural and structural context, demonstrating the fruitfulness of a morphogenetic approach.
Acute Hepatic Injury Associated with Varenicline in a Patient with Underlying Liver Disease
Authors: Franck Andrew J , Sliter Lisa R
Published: July 2009

Objective:

To report a case of acute hepatic injury associated with varenicline.

Case Summary:

A 53-year-old white male with underlying alcoholic liver disease and history of hepatitis C virus infection experienced elevated aminotransferase and alkaline phosphatase levels consistent with acute hepatic injury after initiation of varenicline for smoking cessation. The hepatic injury manifested 4 weeks after initiation of varenicline therapy at 0.5 mg once daily for 3 days, 0.5 mg twice daily for 4 days, and then 1 mg twice daily. Following discontinuation of varenicline, the patient's aminotransferase levels continued to rise for 2 days before steadily decreasing and returning to baseline levels in approximately 4 months. Alkaline phosphatase continued to rise for 8 days after discontinuation of varenicline before returning to baseline within 1 month. Rechallenge was not attempted.

Discussion:

Varenicline is a novel, first-line agent for smoking cessation. The presentation of this patient is most consistent with an acute hepatic injury related to drug toxicity. The pattern of the patient's elevated hepatic enzyme levels is not consistent with his underlying alcoholic liver disease or hepatitis C. Using the Naranjo probability scale, as well as the Counsel for International Organizations of Medical Science/Roussel Uclaf Causality Assessment Method algorithm for drug-induced liver toxicity, we determined that varenicline was the probable cause of the acute hepatic injury. Varenicline was a possible cause of the acute hepatic injury using the algorithm for drug-induced liver toxicity developed by Maria and Victorino. To our knowledge, this is the first report of acute hepatic injury associated with varenicline.

Conclusions:

While the benefits of smoking cessation are likely greater than the risk of hepatic injury, clinicians should be cognizant of this reaction associated with varenicline.
Production and Manufacture of Fine and Coarse Aggregates
Authors: Rockwood Nathan C.
Published: July 2009

The processing of natural and manufactured aggregates is described briefly, including exploration to determine the planning of excavation and transportation methods adapted to local conditions; successive steps in processing— cleaning, washing, crushing, screening or sizing, hydraulic classifying, air separation, fine reduction, special processing to remove “soft” particles, flats, etc., storage in bins and stockpiles, recovery from storage and shipping facilities. Manufacture of slag, burned-clay and lightweight aggregates is described briefly. Plant testing and administrative details of commercial operations are referred to.
The Effect of State Tax Regulations and State Specifications on Tractor Fuels from the Petroleum Industry Standpoint
Authors: Hinkle C. N.
Published: July 2009

In my younger days when I was farming in western Kansas, no one worried about a standardized tractor fuel. Kerosine was the standard fuel. As for octane number, the term wasn't known at that time. If the tractor knocked excessively, we turned on more water or tried to lighten the load. In those days our first concern was to get the tractor started, and then we wondered how long it would run before we had to search the countryside for repairs. A lot of changes have taken place since that time, and I think everyone welcomes the many improvements made in farm tractors. Improvements have also been made in the burning qualities of fuels and, as a result, more efficient tractor engines have been developed. Because of improved tractors and fuels, we have seen an ever growing tractor population, as pointed out by Mr. Everett. Improvement in tractor engines and general design has made the tractor more usable and has caused the farmer to demand the improved tractor fuels. Professor Barger told us what the farmer wants in a tractor fuel. It is the improvement in tractor engines plus the advancements yet to come that make Mr. Bowers interested in the fuels that will be available for tractors when farmers operate their tractors at full power. Mr. Anderson discussed another problem, the complexity of tractor fuels and their taxation which confronts everyone interested in tractors and tractor fuels. In fact, these tax problems are the primary reasons for tractor owners today considering the use of tractor fuels heavier than gasoline. Actually, the tractor owner with the many improvements in his modern tractor, such as starter, lights, rubber tires, etc., wants a volatile fuel, and in states where the tax problem does not appreciably increase his fuel costs, gasoline is the fuel which a majority of the farmers—even owners of two-fuel tractors—now use. My assignment on this program is to discuss “The Effect of State Tax Regulations and State Specifications on Tractor Fuels from the Petroleum Industry Standpoint.” This tractor fuel problem is not a new one, it has been discussed for the past ten to fifteen years. But like the weather, although much discussed, little has been done about it. Perhaps now that scientists have discovered how, by the use of an airplane and a little dry ice or water, they can make it rain or snow, A.S.T.M. Committee D-2 will not consider its problem hopeless and will make progress in standardizing tractor fuels advantageous to the farmer, to the states, to the tractor industry, and to the petroleum industry.
Implementation of Spatial Transformation Rules for Goal-Directed Reaching via Gain Modulation in Monkey Parietal and Premotor Cortex
Authors: Gail Alexander , Klaes Christian , Westendorff Stephanie
Published: July 2009

Planning goal-directed movements requires the combination of visuospatial with abstract contextual information. Our sensory environment constrains possible movements to a certain extent. However, contextual information guides proper choice of action in a given situation and allows flexible mapping of sensory instruction cues onto different motor actions. We used anti-reach tasks to test the hypothesis that spatial motor-goal representations in cortical sensorimotor areas are gain modulated by the behavioral context to achieve flexible remapping of spatial cue information onto arbitrary motor goals. We found that gain modulation of neuronal reach goal representations is commonly induced by the behavioral context in individual neurons of both, the parietal reach region (PRR) and the dorsal premotor cortex (PMd). In addition, PRR showed stronger directional selectivity during the planning of a reach toward a directly cued goal (pro-reach) compared with an inferred target (anti-reach). PMd, however, showed stronger overall activity during reaches toward inferred targets compared with directly cued targets. Based on our experimental evidence, we suggest that gain modulation is the computational mechanism underlying the integration of spatial and contextual information for flexible, rule-driven stimulus–response mapping, and thereby forms an important basis of goal-directed behavior. Complementary contextual effects in PRR versus PMd are consistent with the idea that posterior parietal cortex preferentially represents sensory-driven, “automatic” motor goals, whereas frontal sensorimotor areas are stronger engaged in the representation of rule-based, “inferred” motor goals.
Cortical Oscillatory Activity Is Critical for Working Memory as Revealed by Deficits in Early-Onset Schizophrenia
Authors: Haenschel Corinna , Bittner Robert A. , Waltz James , Haertling Fabian , Wibral Michael , Singer Wolf , Linden David E. J. , Rodriguez Eugenio
Published: July 2009

Impairments in working memory (WM) are a core cognitive deficit in schizophrenia. Neurophysiological models suggest that deficits during WM maintenance in schizophrenia may be explained by abnormalities in the GABAergic system, which will lead to deficits in high-frequency oscillations. However, it is not yet clear which of the three WM phases (encoding, maintenance, retrieval) are affected by dysfunctional oscillatory activity. We investigated the relationship between impairments in oscillatory activity in a broad frequency range (3–100 Hz) and WM load in the different phases of WM in 14 patients with early-onset schizophrenia and 14 matched control participants using a delayed matching to sample paradigm.

During encoding, successful memorization was predicted by evoked theta, alpha, and beta oscillatory activity in controls. Patients showed severe reductions in the evoked activity in these frequency bands. During early WM maintenance, patients showed a comparable WM load-dependent increase in induced alpha and gamma activity to controls. In contrast, during the later maintenance phase, patients showed a shift in the peak of induced gamma activity to the lower WM load conditions. Finally, induced theta and gamma activity were reduced in patients during retrieval.

Our findings suggest that the WM deficit in schizophrenia is associated with impaired oscillatory activity during all phases of the task and that the cortical storage system reaches its capacity limit at lower loads. Inability to maintain oscillatory activity in specific frequency bands could thus result in the information overload that may underlie both cognitive deficits and psychopathological symptoms of schizophrenia.
Poly-(ADP-Ribose) Polymerase-1 Is Necessary for Long-Term Facilitation inAplysia
Authors: Hernández A. Iván , Wolk Jason , Hu Jiang-Yuan , Liu Jinming , Kurosu Takeshi , Schwartz James H. , Schacher Samuel
Published: July 2009

Activity-dependent long-term synaptic plasticity requires gene expression and protein synthesis. Identifying essential genes and studying their transcriptional and translational regulation are key steps to understanding how synaptic changes become long lasting. Recently, the enzyme poly-(ADP-ribose) polymerase 1 (PARP-1) was shown to be necessary for long-term memory (LTM) inAplysia. Since PARP-1 decondenses chromatin, we hypothesize that this enzyme regulates the expression of specific genes essential for long-term synaptic plasticity that underlies LTM. We clonedAplysiaPARP-1 (ApPARP-1) and determined that its expression in sensory neurons is necessary for serotonin (5-HT)-mediated long-term facilitation (LTF) of sensorimotor neuron synapses. PARP enzymatic activity is also required, since transient application of PARP inhibitors blocked LTF. Differential display and RNA analysis of ganglia dissected from intact animals exposed to 5-HT identified the ribosomal RNA genes as PARP-dependent effector genes. The increase in the expression of rRNAs is long lasting and dynamic. Pulse-labeling RNA studies showed a PARP-dependent increase in rRNAs but not in the total RNA 24 h after 5-HT treatment. Moreover, the expression of both theAprpL27a(Aplysiaribosomal protein L27a) and theApE2N(Aplysiaubiquitin-conjugating enzyme E2N) mRNAs also increased after 5-HT. Thus, our results suggest that 5-HT, in part by regulating PARP-1 activity, alters the expression of transcripts required for the synthesis of new ribosomes necessary for LTF.
Get Aroused and Be Stronger: Emotional Facilitation of Physical Effort in the Human Brain
Authors: Schmidt Liane , Cléry-Melin Marie-Laure , Lafargue Gilles , Valabrègue Romain , Fossati Philippe , Dubois Bruno , Pessiglione Mathias
Published: July 2009

Effort magnitude is commonly thought to reflect motivation, but little is known about the influence of emotional factors. Here, we manipulated the emotional state of subjects, via the presentation of pictures, before they exerted physical effort to win money. After highly arousing pictures, subjects produced more force and reported lower effort sensation, regardless of monetary incentives. Functional neuroimaging revealed that emotional arousal, as indexed by postscan ratings, specifically correlated with bilateral activity in the ventrolateral prefrontal cortex. We suggest that this region, by driving the motor cortex, constitutes a brain pathway that allows emotional arousal to facilitate physical effort.
Deviant Ryanodine Receptor-Mediated Calcium Release Resets Synaptic Homeostasis in Presymptomatic 3xTg-AD Mice
Authors: Chakroborty Shreaya , Goussakov Ivan , Miller Megan B. , Stutzmann Grace E.
Published: July 2009

Presenilin mutations result in exaggerated endoplasmic reticulum (ER) calcium release in cellular and animal models of Alzheimer's disease (AD). In this study, we examined whether dysregulated ER calcium release in young 3xTg-AD neurons alters synaptic transmission and plasticity mechanisms before the onset of histopathology and cognitive deficits. Using electrophysiological recordings and two-photon calcium imaging in young (6–8 weeks old) 3xTg-AD and non-transgenic (NonTg) hippocampal slices, we show a marked increase in ryanodine receptor (RyR)-evoked calcium release within synapse-dense regions of CA1 pyramidal neurons. In addition, we uncovered a deviant contribution of presynaptic and postsynaptic ryanodine receptor-sensitive calcium stores to synaptic transmission and plasticity in 3xTg-AD mice that is not present in NonTg mice. As a possible underlying mechanism, the RyR2 isoform was found to be selectively increased more than fivefold in the hippocampus of 3xTg-AD mice relative to the NonTg controls. These novel findings demonstrate that 3xTg-AD CA1 neurons at presymptomatic ages operate under an aberrant, yet seemingly functional, calcium signaling and synaptic transmission system long before AD histopathology onset. These early signaling alterations may underlie the later synaptic breakdown and cognitive deficits characteristic of later stage AD.
Excitability Changes Related to GABAAReceptor Plasticity during Pregnancy
Authors: Maguire Jamie , Ferando Isabella , Simonsen Charlotte , Mody Istvan
Published: July 2009

Alterations in GABAAreceptor (GABAAR) expression and function, similar to those we described previously during pregnancy in the mouse dentate gyrus, may also occur in other brain regions. Here we show, using immunohistochemical techniques, a decreased δ subunit-containing GABAAR (δGABAAR) expression in the dentate gyrus, hippocampal CA1 region, thalamus, and striatum but not in the cerebral cortex. In the face of the highly elevated neurosteroid levels during pregnancy, which can act on δGABAARs, it may be beneficial to decrease the number of neurosteroid-sensitive receptors to maintain a steady-state level of neuronal excitability throughout pregnancy. Consistent with this hypothesis, the synaptic input/output (I/O) relationship in the dentate gyrus molecular layer in response to lateral perforant path stimulation was shifted to the left in hippocampal slices from pregnant compared with virgin mice. The addition of allopregnanolone, at levels comparable with those found during pregnancy (100 nm), shifted the I/O curves in pregnant mice back to virgin levels. There was a decreased threshold to induce epileptiform local field potentials in slices from pregnant mice compared with virgin, but allopregnanolone reverted the threshold for inducing epileptiform activity to virgin levels. According to these data, neuronal excitability is increased in pregnant mice in the absence of allopregnanolone attributable to brain region-specific downregulation of δGABAAR expression. In brain regions, such as the cortex, that do not exhibit alterations in δGABAAR expression, there were no changes in the I/O relationship during pregnancy. Similarly, no changes in network excitability were detected in pregnantGabrd−/−mice that lack δGABAARs, suggesting that changes in neuronal excitability during pregnancy are attributable to alterations in the expression of these receptors. Our findings indicate that alterations in δGABAAR expression during pregnancy result in brain region-specific increases in neuronal excitability that are restored by the high levels of allopregnanolone under normal conditions but under pathological conditions may result in neurological and psychiatric disorders associated with pregnancy and postpartum.
Tenascin-C Is an Inhibitory Boundary Molecule in the Developing Olfactory Bulb
Authors: Treloar Helen B. , Ray Arundhati , Dinglasan Lu Anne , Schachner Melitta , Greer Charles A.
Published: July 2009

We recently described the boundary-like expression pattern of the extracellular matrix molecule tenascin-C (Tnc) in the developing mouse olfactory bulb (OB) (Shay et al., 2008). In the present study, we test the hypothesis that Tnc inhibits olfactory sensory neuron (OSN) axon growth in the developing OB before glomerulogenesis. The period of time before glomerular formation begins, when axons remain restricted to the developing olfactory nerve layer (ONL), is crucial for axon sorting. Here, we show within vitroanalyses that OSN neurite outgrowth is inhibited by Tnc in a dose-dependent manner and that, in stripe assays, axons preferentially avoid Tnc. Using Tnc-null mice, we also show that that glomerular development is delayed in the absence of Tnc. In wild-type mice, OSN axons coalesce into immature or protoglomeruli, which further differentiate and segregate into glomeruli. Glomeruli are first identifiable as discrete structures at birth. In null mice, glomeruli appear immature at birth, remain fused to the ONL, and have a significantly larger diameter compared with wild-type controls. By postnatal day 4, null glomeruli are indistinguishable from controls. Thus, OSN axons appear delayed in their coalescence into glomerular structures. These data correlate with behavioral reports of Tnc-null mice, which are delayed by 24 h in their acquisition of an olfactory behavior (de Chevigny et al., 2006). Collectively, these data demonstrate that Tnc is an inhibitory boundary molecule in the developing OB during a key period of development.
Ethanol Affects Transforming Growth Factor β1-Initiated Signals: Cross-Talking Pathways in the Developing Rat Cerebral Wall
Authors: Powrozek Teresa A. , Miller Michael W.
Published: July 2009

TGFβ1 regulates early cortical development by moving young neurons from the proliferative population and promoting their migration. Altered TGFβ1-regulated signaling can lead to abnormal development underlying microencephaly and migratory defects as in attention deficit hyperactivity disorder, dyslexia, and fetal alcohol spectrum disorder. The present study tested the hypotheses that TGFβ1 signals through cross-talking Smad2/3 and extracellular signal-regulated kinase 1/2 (ERK1/2) pathways and that ethanol simulates these TGFβ1-initiated signals. Slices generated from the telencephalons of 17-d-old rat fetuses were treated with TGFβ1 (0 or 10 ng/ml), ethanol (0, 200, 400, or 800 mg/dl), and/or a pharmacological agent [to block phosphorylation of Smad2/3 (SB431542 or LY364947) or ERK1/2 (PD98059 or U0126)]. In some experiments, the proliferative compartment (the ventricular and subventricular zones; S/VZ) and the postproliferative compartment (intermediate zone/cortical plate/marginal zone) were examined separately. Smad2/3 phosphorylation increased following treatment with TGFβ1, ethanol, and PD98059 (or U0126) plus ethanol. In contrast, SB431542 (and LY364947) blocked Smad2/3 activation and led to the phosphorylation of ERK1/2. These changes revealed cross talk between the two TGFβ1-responsive pathways. TGFβ1-induced effects were primarily in the S/VZ, whereas ethanol induced activation in both compartments. In summary, TGFβ1 activates two separate pathways (Smad2/3 and ERK1/2) that actively interact. Ethanol simulates TGFβ1-induced changes in these signaling systems. Each pathway is preferentially activated during specific developmental events: the Smad2/3 pathway is key for cells exiting from the cycling population and the ERK1/2 pathway is particularly inducible during neuronal migration.
L-Type Voltage-Dependent Calcium Channel Antagonists Impair Perirhinal Long-Term Recognition Memory and Plasticity Processes
Authors: Seoane Ana , Massey Peter V. , Keen Hannah , Bashir Zafar I. , Brown Malcolm W.
Published: July 2009

The perirhinal cortex of the temporal lobe is essential for the familiarity discrimination component of recognition memory. In view of the importance of changes in calcium ion concentration for synaptic plasticity, the present study examined the effects of L-type voltage-dependent calcium channel (VDCC) antagonism on rat perirhinal-based familiarity discrimination processes and plasticity including long-term depression (LTD), long-term potentiation (LTP), and depotentiation. Single doses of three different types of L-type VDCC antagonists, verapamil, diltiazem, and nifedipine, administered systemically, or verapamil administered locally into the perirhinal cortex, impaired acquisition of long-term (24 h) but not shorter-term (20 min) recognition memory. L-type VDCC antagonism also disrupted memory retrieval after 24 h but not 20 min. Differential neuronal activation produced by viewing novel or familiar visual stimuli was measured by Fos expression. L-type VDCC antagonism by verapamil in perirhinal cortex during memory acquisition disrupted the normal pattern of differential Fos expression, so paralleling the antagonist-induced memory impairment. In slices of perirhinal cortex maintainedin vitro, verapamil was without effect on baseline excitability or LTP but blocked LTD and depotentiation. The consistency of effects across the behavioral and cellular levels of analysis provides strong evidence for the involvement of perirhinal L-type VDCCs in long-term recognition memory processes.
Molecular Mechanisms of Lipoic Acid Modulation of T-Type Calcium Channels in Pain Pathway
Authors: Lee Woo Yong , Orestes Peihan , Latham Janelle , Naik Ajit K. , Nelson Michael T. , Vitko Iuliia , Perez-Reyes Edward , Jevtovic-Todorovic Vesna , Todorovic Slobodan M.
Published: July 2009

α-Lipoic acid (1,2-dithiolane-3-pentanoic acid; lipoic acid) is an endogenous compound used to treat pain disorders in humans, but its mechanisms of analgesic action are not well understood. Here, we show that lipoic acid selectively inhibited native CaV3.2 T-type calcium currents (T-currents) and diminished T-channel-dependent cellular excitability in acutely isolated rat sensory neurons. Lipoic acid locally injected into peripheral receptive fields of pain-sensing sensory neurons (nociceptors)in vivodecreased sensitivity to noxious thermal and mechanical stimuli in wild-type but not CaV3.2 knock-out mice. Ensuing molecular studies demonstrated that lipoic acid inhibited recombinant CaV3.2 channels heterologously expressed in human embryonic kidney 293 cells by oxidating specific thiol residues on the cytoplasmic face of the channel. This study provides the first mechanistic demonstration of a nociceptive ion channel modulation that may contribute to the documented analgesic properties of lipoic acidin vivo.
Modellreduktion für parametrisierte Systeme durch balanciertes Abschneiden und InterpolationModel Reduction for Parametric Systems Using Balanced Truncation and Interpolation
Authors: Baur Ulrike , Benner Peter
Published: July 2009

Der Beitrag stellt einen neuen Ansatz zur Parameter-erhaltenden Modellreduktion parametrisierter, linearer Systeme vor. Das Verfahren ist eine Kopplung des balancierten Abschneidens mit Interpolation, sodass Fehlerabschätzungen für die Qualität des reduzierten Systems ableitbar sind. Durch die Verwendung dünner Gitter zur Diskretisierung des Parameterraumes kann das Verfahren auch auf Systeme mit mehreren Parametern angewendet werden.
Normas e redistribuição: um estudo sobre condicionantes internacionais das políticas de combate ao racismo no Brasil
Authors: Godinho Rodrigo de Oliveira
Published: July 2009

Neste artigo, examina-se como a exposição do Estado a normas internacionais pode condicionar a implementação de políticas redistributivas, a partir de estudo de caso relativo ao combate à discriminação racial no Brasil, no período 1995-2005. Conclui que o processo de preparação e de seguimento da Conferência de Durban teria viabilizado equilíbrio propício à implementação de políticas de ação afirmativa.
Observações hidrobiológicas sobre a poluição do rio Capibaribe-Mirim, Pernambuco, Brasil
Authors: Lyra Luiz Tavares de
Published: July 2009

Foi estudada, do ponto de vista ecológico, a poluição da água do rio Capibaribe-Mirim. Foram feitas cerca de 40 coletas de material de janeiro a dezembro de 1974, compreendendo os períodos seco e chuvoso, em 6 estações distribuídas desde o alto curso do rio (perto de Macaparana) até o médio curso (imediações de Goiana). Observaram-se 96 taxa entre espécies e variedades, sendo as mais frequëntes e dominantes as seguintes: Biddulphia laevis (Ehr.) Hustedt, Synedra ulna (Nitzsch) Ehr., Eunotia pectinalis (Kutz) Rabenhost, Nitzschia sigma (Kutz) W. Smith, Navicula cuspidata var. ambigua (Ehr.) Cleve, Eunotia didyma Grunow, Amphora ovalis Kutz., Amphora coffeaeformis Agard, Hantzschia amphioxys (Ehr.) Grunow, Nitzschia triblionella var. victoriae (H.) Grunow, Pinnularia acrospheria Breb., Pinnularia mesolepta (Ehr.) W. Smith, Rhopalodia gibberula (Ehr.) O. Müller, Surirella ovata kutz. É dada especial atenção ás algas Bacillariophyceae e Chlorophyceae. São apresentados, em forma tabular, o inventário ecológico, os índices halóbicos e sapróbicos das espécies, e a freqüência e distribuição das diatomáceas nas diversas estações de coleta.
O vaso dorsal de Triatoma infestans
Authors: Barth Rudolf
Published: July 2009

Descreve-se a anatomia do coração e da aorta de Triatoma infestans, material criado durante alguns anos em cativeiro. O principal resultado das observações é o fato de que, em vez de três pares de ostíolos, o coração possui apenas um único ostíolo em cada uma das suas últimas câmaras. Material capturado no campo (Panstrongylus megistrus) possui normalmente três pares de ostíolos, porém diferentes em tamanho e localização.
Equivalência conceitual, de itens e semântica da versão brasileira do instrumento Dysfunctional Voiding Scoring System (DVSS) para avaliação de disfunção do trato urinário inferior em crianças
Authors: Rizzini Marta , Donatti Teresinha Lermen , Bergamaschi Denise Pimentel , Brunken Gisela Soares
Published: July 2009

Investiga-se a equivalência conceitual, de itens e semântica entre o instrumento Dysfunctional Voiding Scoring System (DVSS), utilizado para avaliar a disfunção funcional do trato urinário inferior em crianças, concebido em inglês e uma versão em português. Na primeira etapa realizou-se a avaliação da equivalência conceitual e de itens, seguida de duas traduções do instrumento original para o português. Na segunda etapa foram realizadas 63 entrevistas, com crianças de 3 a 10 anos e responsáveis, e modificação de itens segundo dificuldades de interpretação. Na terceira etapa foi realizada a retradução do instrumento em português para o inglês e avaliação da equivalência semântica. Na quarta etapa, a versão pré-teste foi aplicada em vinte duplas de crianças de 3 a 10 anos e responsáveis. Apresenta-se o instrumento em português com equivalência conceitual, de itens e semântica. Sugere-se que a aplicação do DVSS seja realizada por meio de entrevista por profissional treinado e não baseada em autopreenchimento como proposto no instrumento original.
O desafio da descentralização do Sistema Único de Saúde em município de grande porte: o caso de São Paulo, Brasil
Authors: Spedo Sandra Maria , Tanaka Oswaldo Yoshimi , Pinto Nicanor Rodrigues da Silva
Published: July 2009

A descentralização do Sistema Único de Saúde (SUS) ainda enfrenta importantes desafios, em particular a busca de alternativas para grandes municípios. Por se caracterizar como um processo eminentemente político, variáveis político-institucionais, dentre as quais se destaca a capacidade de gestão do nível local, são determinantes para a conformação da descentralização em cada contexto. Utilizando o referencial do triângulo de governo para avaliar a capacidade de gestão, realizou-se um estudo de caso, com o objetivo de analisar o processo de descentralização do SUS no Município de São Paulo, Brasil, a maior metrópole brasileira. Pela análise de entrevistas com gestores selecionados e documentos da gestão, identificou-se um movimento de centralização da saúde na gestão municipal 2005-2008, acompanhado do desconcerto das estruturas locorregionais da Secretaria Municipal de Saúde, o que resultou no esvaziamento técnico e político dessas instâncias. Apesar dos limites da descentralização, destaca-se sua potência enquanto estratégia operacional para alcançar os objetivos do SUS. Aponta-se a necessidade de retomar o processo de descentralização da saúde no Município de São Paulo que, além de avançar para instâncias locorregionais, esteja articulado à descentralização da gestão pública municipal.
Oferta e utilização de serviços de saúde bucal no Amazonas, Brasil: estudo de caso em população ribeirinha do Município de Coari
Authors: Cohen-Carneiro Flávia , Souza-Santos Reinaldo , Pontes Danielson Guedes , Salino Alessandra Valle , Rebelo Maria Augusta Bessa
Published: July 2009

O presente estudo de caso teve o objetivo de descrever a oferta e utilização de serviços odontológicos em duas comunidades ribeirinhas do Município de Coari, Amazonas, Brasil. Para tanto, foram colhidos dados sobre freqüência de utilização de serviços de saúde bucal, por entrevistas estruturadas com indivíduos acima de 18 anos, e dados sobre oferta de serviços obtidos por entrevistas semi-estruturadas com informantes-chave. Nas análises bivariadas, embora sem diferença estatística, os indivíduos da comunidade mais distante da sede do município apresentaram maior tempo decorrido da última consulta, e menor proporção de atendimentos pelo serviço público e por barcos de saúde. A análise qualitativa das entrevistas revelou: ausência de serviço odontológico permanente nas comunidades; oferta esporádica através de barcos da saúde, com menor ocorrência dos serviços na comunidade mais distante; alto custo do deslocamento do ribeirinho à sede do município; e tratamento odontológico voltado para o controle da dor, basicamente se resumindo à extração dentária. O acesso precário dos ribeirinhos aos serviços de saúde bucal aponta para a necessidade de implantação de medidas amplas de promoção de saúde, aliada a maior oferta de serviços.
A identidade em discursos de taxistas
Authors: Velôso Thelma Maria Grisi , Oliveira Filho Pedro de , Medeiros Carolina Silva de , Araújo Audizélia dos Santos
Published: July 2009

Este artigo é resultado de uma pesquisa mais ampla, cujo objetivo principal foi o de analisar a construção da identidade em discursos de taxistas que fazem em seus veículos o transporte alternativo entre os municípios de João Pessoa e Campina Grande - PB. Optou-se por uma pesquisa qualitativa, por meio da qual foram obtidos treze relatos orais de vida - sete em Campina Grande e seis em João Pessoa -, os quais foram submetidos à análise de discurso. Nos relatos, predominam descrições em que os taxistas se posicionam como membros desencantados de uma profissão decadente, que mal lhes garante a sobrevivência. A situação atual, difícil e instável, é contrastada insistentemente com um passado financeiramente mais estável. Em seus discursos, os entrevistados retratam si mesmos e o grupo ao qual pertencem como trabalhadores que lutam pela sobrevivência, legitimando, assim, a necessidade de optar pelo transporte alternativo.
O livro didático na perspectiva da formação de professores
Authors: Pessoa Rosane Rocha
Published: July 2009

Há provavelmente tanto razões a favor quanto contra a utilização do livro didático no ensino de língua estrangeira, mas o fato é que, no Brasil, poucos são os contextos educacionais em que não se adota um livro didático. A relação entre essa ampla adoção do livro didático e os modelos tradicionais de formação profissional, nos quais os professores aprendem a aplicar em suas práticas pedagógicas teorias produzidas por agentes externos, parece bastante óbvia. No entanto, nos modelos atuais de formação, que objetivam principalmente que os professores construam conhecimento sobre ensino e aprendizagem, será que há espaço para o livro didático ou deveria o professor criar os seus próprios materiais? Neste texto, abordaremos esse tópico, levando em consideração a percepção de alunos do curso de graduação em Letras da UFG sobre a utilização do livro didático no ensino de inglês.
Ensinar a escrever o texto acadêmico: as múltiplas funções do orientador
Authors: Riolfi Claudia Rosa , Andrade Emary
Published: July 2009

O presente estudo toma as observações de um orientador de mestrado em uma área das ciências humanas que foram encontradas em rascunhos produzidos por duas informantes ao longo de 36 meses de trabalho como objeto de análise. Seu objetivo principal é estudar como a ação de ensinar a escrever o texto acadêmico se configura. Para tal fim, partilhamos a hipótese de trabalho de Pommier (1993), segundo a qual os modos pelos quais alguém aprende a escrever atualizam, de forma metafórica, os caminhos por meio dos quais sua subjetivação se deu. Tendo a psicanálise de orientação lacaniana como campo em que trabalhamos, inserimo-nos na continuidade dos trabalhos que vêm defendendo a possibilidade do agenciamento da singularidade de quem escreve em direção a uma universidade produtiva. A partir da análise dos dados, foi possível depreender cinco diferentes funções exercidas pelo orientador para ensinar suas alunas a escrever um texto acadêmico, a saber: 1) diretor de trabalhos, 2) leitor, 3) coautor, 4) revisor e 5) agente do real. Dessa forma, pudemos ratificar a alegada dificuldade para orientar um trabalho. Pudemos, também, ter uma visão mais detalhada da complexidade de escrever um texto acadêmico.
Análise comparativa da criação dos camarões-rosa Farfantepenaeus brasiliensis e FarfantePenaeus paulensis criados em gaiolas em ambiente estuarino
Authors: Lopes Diogo Luiz de Alcantara , Wasielesky Junior Wilson , Ballester Eduardo Cupertino , Peixoto Sílvio Ricardo Maurano
Published: July 2009

A análise da criação de Farfantepenaeus brasiliensis e Farfantepenaeus paulensis em gaiolas, na Lagoa dos Patos, Rio Grande do Sul (RS), foi realizada a partir de juvenis produzidos em cativeiro com peso médio inicial de aproximadamente 1,2g. O experimento foi realizado em seis gaiolas (três gaiolas/tratamento), com abertura de malha de 5mm, área de fundo de 4m² durante 65 dias. A distribuição dos indivíduos nos tratamentos (F. brasiliensis e F. paulensis) foi aleatória, mantendo-se a densidade de 20 camarões m-2 nas unidades experimentais. A cada 15 dias foram realizadas biometrias para ajuste da quantidade de ração fornecida e avaliação do crescimento dos camarões. Ao final do experimento, foi realizada a biometria total dos camarões para avaliação da sobrevivência. Não houve diferença significativa entre a sobrevivência de F. brasiliensis (94,17 ± 9,04) e F. paulensis (98,50±0,71). O peso médio final foi significativamente maior para o F. brasiliensis (7,98± 0,94g); porém, não foram observadas diferenças significativas na produção de biomassa (127,81±17,93 e 126,65±1,74g m-2) e conversão alimentar aparente (1,39±0,27 e 1,57±0,09) de F. brasiliensis e F. paulensis, respectivamente. Os resultados indicam que F. brasiliensis apresenta potencial para produção em estruturas alternativas e incentivam que novas pesquisas sejam realizadas para o desenvolvimento de um pacote tecnológico de produção dessas espécies.
Avaliação: um contrato de trabalho
Authors: Silva Maria Regina Gomes da
Published: July 2009

Este artigo apresenta, tendo em vista perplexidades constituídas a partir de uma leitura acerca do funcionamento do modelo tradicional de ensino, considerações sobre a Proposta Pedagógica Assimilação Solidária, AS (Baldino, 1995a). Proposta interventora, a AS muda o conceito de mérito, pois considera, ao lado do prêmio ao saber, o justo prêmio ao trabalho coletivo produzido em sala de aula. O instrumento fundamental da AS é um contrato de trabalho, negociado entre professor e alunos, que vincula a avaliação e o trabalho em grupos na sala de aula.
Morphometric and ultrastructural studies of the effect of infrared laser on rabbit temporo-mandibular joint fibroblasts
Authors: Uribe Ricardo Cornejo , Vargas Fernando Matamala , Mella Héctor Silva , Onate Orlando Garrido
Published: July 2009

The infrared laser beams has been successfully used in joint lesions treatment due to its analgesic anti inflamatory and healing action, and on a cellular level, inducing an accentuated synthesis of ATP, activating cellular proliferation and collagen synthesis. Samples of normal-control and irradiated tissue from temporo-mandibular joint disc of rabbit, were obtained, with daily doses of 2 joules/cm²during 10 consecutive days. They were prepared for transmission electronic microscopy.Transmission electronic micrographs of normal and irradiated fibroblasts were obtained with final increase of 11.500 X for morphometric studies with the purpose of quantifying the volumetric fractions of the cellular components pertaining to the mentioned cellular types. Volumetric fractions of the quoted cell corresponding to nucleus, cytoplasm, rough endoplasmatic reticule, eu and heterochromatin were evaluated. In the same manner, the nucleus - cytoplasmatic relation and the area of each cellular type were quantified. The results derived from the morphometric comparative study between the normal and irradiated fibroblasts indicated that there were significant differences with respect to the volumetric fractions of euchromatin and heterochromatin and fundamentally in the cellular areas of both types. On the other hand, the rest of quantified parameters remained constant. It could be concluded that the cellular function reflected in collagen synthesis and secretion remained constant in both cellular types. However, by means of infrared laser stimulations, this fibroblast facilitated protein synthesis, due to high percentage of transcriptionally active euchromatine.
Reproductive biology of weakly electric fish Eigenmannia trilineata López and Castello, 1966 (Teleostei, Sternopygidae)
Authors: Giora Júlia , Fialho Clarice Bernhardt
Published: July 2009

This study described the reproductive biology of a population of the weakly electric fish Eigenmannia trilineata from southern Brazil, providing the information on the estimation of reproductive period, fecundity, spawning type, first maturation size, and analysis of gonadal morphology and histology of the species, relating these data to alimentary and abiotic characters. The species showed a relatively long reproductive period, a relative fecundity of 0.27 oocytes per mg of total weight and a parcelled spawning type. First maturation size estimated for the females was 80.5 mm and for the males 63.5 mm of total length. Sex ratio did not differ from 1:1 under a X²test (α= 0.01) during all the sampled months. Sexual dimorphism was related to total length, and males had larger total length than females. The abiotic factors photoperiod and water conductivity presented significant correlations with female GSI, while male GSI presented a significant correlation only with photoperiod.
Benthic Community zonation in a breakwater on the north coast of the state of Rio de Janeiro, Brazil
Authors: Masi Bruno Pereira , Macedo Isabela Maria , Zalmon Ilana Rosental
Published: July 2009

The present study presents the vertical zonation pattern of the intertidal benthic organisms on granitic boulders in the Farol de São Tomé beach (22º02'S, 41º03'W), Rio de Janeiro State. Four sampling profiles using 20 x 20 cm quadrats through a photo quadrat technique revealed four horizontal bands: (1) Littoral Fringe characterized by empty space and Littorina; (2) Upper eulittoral mainly occupied by Chthamalus and bare rock; (3) Lower eulittoral characterized by Chthamalus, Phragmatopoma, Ulva and Centroceras; and (4) Sublittoral Fringe characterized by Ulva, Phragmatopoma and Hypnea. The high variability in the relative abundance of the dominant species among the profiles may be attributed to the high topographic irregularity, reflecting in different wave action intensity at the same height, and consequently favoring the establishment of different species. The frequent substrate alternation from granitic rock to Phragmatopoma sandy reefs might contribute to the small-scale spatial variability. The implantation of a breakwater on an area without natural rocky shores allowed the study of intertidal benthic communty zonation, and provide a baseline for the experimental studies.