bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal Leukemia Inhibitory Factor (LIF) Promotes Fetal Neurogenesis via a LIF-ACTH-LIF Signaling Relay Pathway
Authors: Simamura Eriko , Shimada Hiroki , Higashi Nobuaki , Uchishiba Maimi , Otani Hiroki , Hatta Toshihisa
Published: February 2010

Leukemia inhibitory factor (LIF) promotes the proliferation of neuronal progenitor cells in the cerebrum. However, it remains unclear how fetal LIF level is regulated. Here we show evidence that maternal LIF signals drive fetal LIF levels via the placenta, thereby promoting neurogenesis in the fetal brain in rats. Chronological changes showed that LIF concentration in fetal sera (FS) and fetal cerebrospinal fluid peaked at gestational day (GD) 15.5, after the peak of maternal LIF at GD14.5. LIF injection into rat dams at GD15.5 increased the level of ACTH in FS and subsequently increased LIF levels in FS and fetal cerebrospinal fluid. The elevation of fetal LIF after LIF injection into dams was inhibited by in utero injection of anti-ACTH antibody into fetuses. Cultured syncytiotrophoblasts, which express the LIF receptor and glycoprotein 130, were induced to secrete ACTH and up-regulate Pomc expression by the addition of LIF. Nucleated red blood cells from fetuses at GD15.5, but not GD13.5 or GD17.5, displayed LIF secretion in response to ACTH. Moreover, injection of LIF into dams at GD13.5 or GD17.5 did not result in elevation of ACTH or LIF in fetuses. The labeling index of 5-bromo-2′-deoxyuridine-positive cells in the ventricular zone of the cerebral neocortex increased 24 h after injection of LIF into dams at GD15.5 but not GD13.5 or GD17.5. These results suggest that in rats maternal LIF induces ACTH from the placenta, which in turn induces fetal nucleated red blood cells to secrete LIF that finally increases neurogenesis in fetuses around GD15.
Selective Activation of Estrogen Receptor-β Target Genes by 3,3′-Diindolylmethane
Authors: Vivar Omar I. , Saunier Elise F. , Leitman Dale C. , Firestone Gary L. , Bjeldanes Leonard F.
Published: February 2010

3,3′-Diindolylmethane (DIM) is a natural compound found in cruciferous vegetables that has antiproliferative and estrogenic activity. However, it is not clear whether the estrogenic effects are mediated through estrogen receptor (ER)α, ERβ, or both ER subtypes. We investigated whether DIM has ER subtype selectivity on gene transcription. DIM stimulated ERβ but not ERα activation of an estrogen response element upstream of the luciferase reporter gene. DIM also selectively activated multiple endogenous genes through ERβ. DIM did not bind to ERβ, indicating that it activates genes by a ligand-independent mechanism. DIM causes ERβ to bind regulatory elements and recruit the steroid receptor coactivator (SRC)-2 coactivator, which leads to the activation of ER target genes. Silencing of SRC-2 inhibited the activation of ER target genes, demonstrating that SRC-2 is required for transcriptional activation by DIM. Our results demonstrate that DIM is a new class of ERβ-selective compounds, because it does not bind to ERβ, but instead it selectively recruits ERβ and coactivators to target genes.
A Locus on Mouse Chromosome 2 Is Involved in Susceptibility to Congenital Hypothyroidism and Contains an Essential Gene Expressed in Thyroid
Authors: Amendola Elena , Sanges Remo , Galvan Antonella , Dathan Nina , Manenti Giacomo , Ferrandino Giuseppe , Alvino Francesca Maria , Di Palma Tina , Scarfò Marzia , Zannini Mariastella , Dragani Tommaso A. , De Felice Mario , Di Lauro Roberto
Published: February 2010

We report here the mapping of a chromosomal region responsible for strain-specific development of congenital hypothyroidism in mice heterozygous for null mutations in genes encoding Nkx2-1/Titf1 and Pax8. The two strains showing a differential predisposition to congenital hypothyroidism contain several single-nucleotide polymorphisms in this locus, one of which leads to a nonsynonymous amino acid change in a highly conserved region of Dnajc17, a member of the type III heat-shock protein-40 (Hsp40) family. We demonstrate that Dnajc17 is highly expressed in the thyroid bud and had an essential function in development, suggesting an important role of this protein in organogenesis and/or function of the thyroid gland.
Functional molecular imaging of ILK-mediated Akt/PKB signaling cascades and the associated role of β-parvin
Authors: Kimura Mariko , Murakami Takashi , Kizaka-Kondoh Shinae , Itoh Masayuki , Yamamoto Keiji , Hojo Yukihiro , Takano Makoto , Kario Kazuomi , Shimada Kazuyuki , Kobayashi Eiji
Published: February 2010

Visualization and quantification of the dynamics of protein-protein interactions in living cells can be used to explore the macromolecular events involved in signal transduction processes. In this study, functional molecular imaging using a luciferase-based complementation method demonstrated how the integrin-linked kinase (ILK)-mediated protein complex controls downstream signals. The luciferase complementation assay showed that Akt1 preferentially binds to β-parvin rather than to ILK within the complex. Moreover, photon flux from the interaction between β-parvin and Akt1 increased following serum stimulation, and the β-parvin—Akt1 interaction was dependent on phosphoinositide 3-kinase. Intriguingly, small interfering (si)RNA-mediated β-parvin knockdown increased photon flux from the interaction between ILK and Akt1, leading to stabilization of hypoxia-inducible factor-1α and increased expression of vascular endothelial growth factor-A. These data from functional molecular imaging demonstrated that β-parvin plays a regulatory role in the ILK-mediated Akt (also called protein kinase B) signaling cascades, suggesting that β-parvin might be a crucial modulator of cell survival.
Roadblocks en route to the clinical application of induced pluripotent stem cells
Authors: Lowry William E. , Quan William L.
Published: February 2010

Since the first studies of human embryonic stem cells (hESCs) and, more recently, human induced pluripotent stem cells (hiPSCs), the stem-cell field has been abuzz with the promise that these pluripotent populations will one day be a powerful therapeutic tool. Although it has been proposed that hiPSCs will supersede hESCs with respect to their research and/or clinical potential because of the ease of their derivation and the ability to create immunologically matched iPSCs for each individual patient, recent evidence suggests that iPSCs in fact have several underappreciated characteristics that might mean they are less suitable for clinical application. Continuing research is revealing the similarities, differences and deficiencies of various pluripotent stem-cell populations, and suggests that many years will pass before the clinical utility of hESCs and hiPSCs is realized. There are a plethora of ethical, logistical and technical roadblocks on the route to the clinical application of pluripotent stem cells, particularly of iPSCs. In this Essay, we discuss what we believe are important issues that should be considered when attempting to bring hiPSC-based technology to the clinic.
Opposing effects of retinoic acid and FGF9 onNanos2expression and meiotic entry of mouse germ cells
Authors: Barrios Florencia , Filipponi Doria , Pellegrini Manuela , Paronetto Maria Paola , Di Siena Sara , Geremia Raffaele , Rossi Pellegrino , De Felici Massimo , Jannini Emmanuele A. , Dolci Susanna
Published: February 2010

In the mouse, three genes that are homologous to the Drosophila Nanos (Nos) gene have been identified. Deletion of one of these genes, Nanos2, results in male sterility, owing to loss of germ cells during fetal life. Before apoptosis, Nanos2-null gonocytes enter meiosis, suggesting that Nanos2 functions as a meiotic repressor. Here, we show that Nanos2 is continuously expressed in male germ cells from fetal gonocytes to postnatal spermatogonial stem cells. We observed that the promeiotic factor AtRA, an analog of retinoic acid (RA), downregulates NANOS2 levels, in both fetal and postnatal gonocytes, while promoting meiosis. Interestingly, FGF9, a growth factor crucial for sex differentiation and survival of fetal gonocytes, upregulates levels of NANOS2 in both male and female primordial germ cells (PGCs) and in premeiotic spermatogonia. This effect was paralleled by an impairment of meiotic entry, suggesting that FGF9 acts as an inhibitor of meiosis through the upregulation of Nanos2. We found that NANOS2 interacts with PUM2, and that these two proteins colocalize in the ribonucleoparticle and polysomal fractions on sucrose gradients, supporting the notion that they bind RNA. Finally, we found that recombinant NANOS2 binds to two spermatogonial mRNAs, Gata2 and Taf7l, which are involved in germ-cell differentiation.
Retromer-mediated direct sorting is required for proper endosomal recycling of the mammalian iron transporter DMT1
Authors: Tabuchi Mitsuaki , Yanatori Izumi , Kawai Yasuhiro , Kishi Fumio
Published: February 2010

Endosomal recycling of the mammalian iron transporter DMT1 is assumed to be important for efficient and rapid uptake of iron across the endosomal membrane in the transferrin cycle. Here, we show that the retromer, a complex that mediates retrograde transport of transmembrane cargoes from endosomes to the trans-Golgi network, is required for endosomal recycling of DMT1-II, an alternative splicing isoform of DMT1. Bacterially expressed Vps26-Vsp29-Vsp35 trimer, a retromer cargo recognition complex, specifically binds to the cytoplasmic tail domain of DMT1-II in vitro. In particular, this binding is dependent on a specific hydrophobic motif of DMT1-II, which is required for its endosomal recycling. DMT1-II colocalizes with the Vps35 subunit of the retromer in TfR-positive endosomes. Depletion of the retromer by siRNA against Vps35 leads to mis-sorting of DMT1-II to LAMP2-positive structures, and expression of siRNA-resistant Vps35 can rescue this effect. These findings demonstrate that the retromer recognizes the recycling signal of DMT1-II and ensures its proper endosomal recycling.
Sirtuin-3 deacetylation of cyclophilin D induces dissociation of hexokinase II from the mitochondria
Authors: Shulga Nataly , Wilson-Smith Robin , Pastorino John G.
Published: February 2010

We demonstrate that the transition from a reliance on glycolysis to oxidative phosphorylation in a transformed cell line is dependent on an increase in the levels and activity of sirtuin-3. Sirtuin-3 deacetylates cyclophilin D, diminishing its peptidyl-prolyl cis-trans isomerase activity and inducing its dissociation from the adenine nucleotide translocator. Moreover, the sirtuin-3-induced inactivation of cyclophilin D causes a detachment of hexokinase II from the mitochondria that is necessary for stimulation of oxidative phosphorylation. These results might have important implications for the role of sirtuin-3 in the metabolism of some cancer cells and their susceptibility to mitochondrial injury and cytotoxicity.
Swallowable medical devices for diagnosis and surgery: The state of the art
Authors: Toennies J L , Tortora G , Simi M , Valdastri P , Webster R J
Published: February 2010

The first wireless camera pills created a revolutionary new perspective for engineers and physicians, demonstrating for the first time the feasibility of achieving medical objectives deep within the human body from a swallowable, wireless platform. The approximately 10 years since the first camera pill has been a period of great innovation in swallowable medical devices. Many modules and integrated systems have been devised to enable and enhance the diagnostic and even robotic capabilities of capsules working within the gastrointestinal (GI) tract. This article begins by reviewing the motivation and challenges of creating devices to work in the narrow, winding, and often inhospitable GI environment. Then the basic modules of modern swallowable wireless capsular devices are described, and the state of the art in each is discussed. This article is concluded with a perspective on the future potential of swallowable medical devices to enable advanced diagnostics beyond the capability of human visual perception, and even to directly deliver surgical tools and therapy non-invasively to interventional sites deep within the GI tract.
Analysis of Forces and Moments in Gerotor Pumps
Authors: Ivanovic L , Devedzic G , Miric N , Cukovic S
Published: February 2010

This article presents the analyses of the forces and moments between gears in contact with a gerotor pump. The objective was to reach a more accurate solution for the problems related to load distribution in trochoidal pumps with fixed shaft axes. Calculation of contact forces is complex due to the simultaneous contact of several trochoidal teeth during the load transfer and additional compressive fluid forces that act on the teeth flanks. A simple physical model and a suitable analytical model are used for this analysis. Compressive fluid forces are simulated with single force applied in the middle of the line that separates the suction and upward pressure zone. During the teeth engagement there is also a change in fluid volumes between teeth. This creates pressure change that needs to be considered and calculated at an arbitrary moment of the engagement process. Finite element analysis (FEA) was used to determine the reaction forces that depend on instantaneous moments as well. Analysis shows that if a chamber pressure variation is taken into account, higher values of driving moment and support reaction forces will be generated. Designers can use the obtained results to develop a higher efficiency gerotor pumps.
Review of the systems analysis of interactions between the thermal, lubricant, and combustion processes of diesel engines
Authors: Burke R D , Brace C J , Hawley J G , Pegg I
Published: February 2010

A review of technologies surrounding the thermal management system of the modern diesel engine with increased attention on fuel consumption is presented. A system-based approach has been adopted, looking at the interaction with other key systems. Previous innovation has aimed at reducing the power consumption of the cooling system or incorporating different cooling strategies and improving the engine warm-up rate for improved fuel consumption by higher operating temperatures. Electrical pumps can operate independently of the engine speed, and precision cooling and nucleate boiling have improved the heat transfer within the engine, reducing coolant flow requirements by 90 per cent. Improved warm-up rates have been demonstrated by using reduced thermal inertia or energy recovery systems either simulated on the test rig or through heat exchangers with exhaust gases. The resultant reduction in the fuel consumption is a result of various effects of the temperature on both the lubricating system and the combustion process. Despite difficulties in accurately measuring the engine friction, studies suggest that an increase in the engine temperature from 50°C to 80°C reduces the engine friction by 44 per cent because of 67 per cent lower oil viscosity. Simultaneous reduction in the emissions of nitogen oxides (NO x) and the fuel consumption of 13.5 per cent and 0.7 per cent respectively have been achieved by including the engine thermal system in the calibration procedure. However, in-cylinder data needs to be studied to understand fully the mechanisms involved. Hotter engine temperatures reduce ignition delay, making combustion occur earlier in the cycle, which has a positive effect on the fuel consumption but a negative effect on the NO x emissions. Engine thermal management requires a system-based approach if the effects are to be fully understood but offers potential as an additional parameter in engine calibration.
Combustion and particulate emission characteristics of a diesel engine fuelled with diesel—dimethoxymethane blends
Authors: Zhu R-J , Wang X-B , Miao H , Huang Z-H
Published: February 2010

The effect of fuel constituents on the combustion and particle emission characteristics of a compression ignition engine fuelled with diesel—dimethoxymethane (DMM) blends is investigated experimentally. Four engine loads at the maximum torque engine speed of 1600r/min and rated engine speed of 2200r/min were carried out respectively. Three diesel—DMM blended fuels containing 15 vol %, 30 vol %, and 50 vol % DMM, corresponding to 6.35 mass %, 12.67 mass %, and 21.11 mass % oxygen in the blends were used. The study showed that the ignition delay experienced a slight increase while the rapid combustion duration and the total combustion duration decreased with increase in the DMM fraction in the fuel blends. The maximum cylinder pressure, the maximum rate of pressure rise, and the maximum rate of heat release increase with the addition of DMM to the blended fuels. Moreover, the smoke concentration decreases with increase in the oxygen mass fraction in the blends and the reduction rate reaches 80 per cent for 50 vol % DMM in the blend under a high engine load. The influence of DMM on the nanoparticulate distribution was also studied in the tests and it was found that the total number of nanosized particulates are all reduced with increase in the oxygen content in the blends.
Unmanned aerial vehicle aerodynamic model identification from a racetrack manoeuvre
Authors: Chumalee S , Whidborne J F
Published: February 2010

The determination of aircraft stability and control derivatives from wind-tunnel and computational fluid dynamics data can be an expensive and time-consuming procedure. This case study shows how linear system identification techniques can be used to obtain this information with sufficient accuracy to design a satisfactory flight control system for an aerial target of the Royal Thai Air Force. Just one flight was undertaken, using a racetrack manoeuvre, to provide the data for identification and validation. The system parameters were identified and a flight control system was designed. Hardware-in-the-loop simulation was used to perform initial tests on the controller and to test the control system hardware and software. A second flight was performed to test the resulting controller, and a satisfactory performance was obtained without the need to adjust the controller gains.
Dynamic intelligent autonomous control of an asteroid lander
Authors: Brown B , McInnes C , Allouis E
Published: February 2010

One of the future flagship missions of the European Space Agency is the asteroid sample return mission Marco-Polo. Although there have been a number of past missions to asteroids, a sample has never been successfully returned. The return of asteroid regolith to the Earth's surface introduces new technical challenges. This article develops attitude control algorithms for the descent phase onto an asteroid in micro-gravity conditions and draws a comparison between the algorithms considered. Two studies are also performed regarding the fault detection isolation and recovery of the control laws considered. The potential of using direct adaptive control (DAC) as a controller for the surface sampling process is also investigated. The use of a DAC controller incorporates increased levels of robustness by allowing real-time variation of control gains. This leads to better response to uncertainties encountered during missions.
Using Simulation Early in the Design of a Fuel Injector Production Line
Authors: Tongarlak Mustafa H. , Ankenman Bruce , Nelson Barry L. , Borne Laurent , Wolfe Kyle
Published: February 2010

In this paper, we describe how Delphi Corporation used simulation in the concept-development phase of a new multimillion-dollar fuel injector production line. Delphi wanted to assess the financial viability of production targets and identify the critical features of the line on which it would focus its design-improvement efforts.
Independence of Capacity Ordering and Financial Subsidies to Risky Suppliers
Authors: Babich Volodymyr
Published: February 2010

The risk of supply disruptions because of suppliers' financial problems plays a prominent role in manufacturers' risk portfolios. Even large suppliers (e.g., Delphi) could file for bankruptcy, and manufacturers' actions, such as financial subsidies to suppliers, profoundly affect suppliers' financial health. Using a dynamic, stochastic, periodic-review model of the manufacturer's joint capacity reservation and financial subsidy decisions and a general firm-value model of the supplier's financial state, this paper addresses the following questions: What is the optimal joint capacity ordering and financial subsidy policy for the manufacturer? Must subsidy and capacity ordering decisions be made jointly? How good are the recommendations from the traditional procurement models, which ignore the benefits of controlling the supplier's financial state through subsidies? The paper presents general assumptions that allow the manufacturer to make ordering decisions independent of subsidy decisions and investigates interactions between ordering and subsidy decisions when these assumptions are violated. Conditions are presented for the optimal subsidy policy to have a “subsidize-up-to” structure and for the optimal ordering decisions to be newsvendor fractiles.
Contesting the ‘national interest’ and maintaining ‘our lifestyle’: A discursive analysis of political rhetoric around climate change
Authors: Kurz Tim , Augoustinos Martha , Crabb Shona
Published: February 2010

The release of the fourth United Nations Intergovernmental Panel on Climate Change (IPCC) report in February 2007 prompted a flood of responses from political leaders around the globe. Perhaps nowhere was this more apparent than in Australia, where its release coincided with the first sitting week of the Australian Parliament, in an election year. The current study involves a discursive analysis of climate change rhetoric produced by politicians from the major Australian political parties in the period following the release of the IPCC leading up to the national election. Data include both transcripts of parliamentary debate and statements directly broadcast in the media. The analysis focuses on the various ways in which the issue of climate change was invoked and rhetorically managed by each of the two parties in the lead up to the election. In particular, it focuses on the ways in which appeals to the ‘national interest’ and ‘lifestyle maintenance’, both regular features of political rhetoric, were mobilized by both parties to discursively manage their positions on the climate change issue. Implications of the ways in which such appeals were constructed are discussed in relation to the discursive limits of the ways in which the issue of climate change is constructed in public debate.
Characterizing macro-voids of uncompressed mats and finished particleboard panels using response surface methodology and X-ray CT
Authors: Sackey Emmanuel K. , Smith Gregory D.
Published: February 2010

Macro-voids in the core of uncompressed particle mats and pressed particleboard manufactured from novel particleboard furnishes were characterized using a response surface method with mixture design and X-ray CT technology. Industrial particles were screened into core-fine, medium, and coarse size classes and their dimensions were measured. Wooden blocks measuring 10 times the mean dimensions of these particles were cut and used as surrogates for the industrial particles. Novel particle mixtures were prepared by mixing together various proportions from each particle size class. The mixtures were packed to simulate particleboard mat formation and a pre-pressed particle mat. Panels were then fabricated from the industrial furnish mixtures. The void fraction of the packed particles and the finished panels were measured and correlated with the IB strength and edge screw withdrawal resistance. Results indicated that densely packed hammer-milled industrial particles had a maximum void fraction of 63.2%. The void fraction of a randomly packed, dense particle mat was described using a full cubic model. In both particle mats without resin and the pressed panels, increasing the core-fine content decreased void volume, whereas increasing coarse particle fraction increased void volume in the mat only. The macro-void ratio in the pressed panels increased exponentially with void fraction for the randomly packed, loose particle mats. Particle mixtures that resulted in boards with the smallest void fraction were not necessarily the strongest boards; low density particleboard panels made from the novel 100% coarse mixture were found to have the highest mechanical properties.
Transient Early-Life Forebrain Corticotropin-Releasing Hormone Elevation Causes Long-Lasting Anxiogenic and Despair-Like Changes in Mice
Authors: Kolber Benedict J. , Boyle Maureen P. , Wieczorek Lindsay , Kelley Crystal L. , Onwuzurike Chiamaka C. , Nettles Sabin A. , Vogt Sherri K. , Muglia Louis J.
Published: February 2010

During development, early-life stress, such as abuse or trauma, induces long-lasting changes that are linked to adult anxiety and depressive behavior. It has been postulated that altered expression of corticotropin-releasing hormone (CRH) can at least partially account for the various effects of stress on behavior. In accord with this hypothesis, evidence from pharmacological and genetic studies has indicated the capacity of differing levels of CRH activity in different brain areas to produce behavioral changes. Furthermore, stress during early life or adulthood causes an increase in CRH release in a variety of neural sites. To evaluate the temporal and spatial specificity of the effect of early-life CRH exposure on adult behavior, the tetracycline-off system was used to produce mice with forebrain-restricted inducible expression of CRH. After transient elevation of CRH during development only, behavioral testing in adult mice revealed a persistent anxiogenic and despair-like phenotype. These behavioral changes were not associated with alterations in adult circadian or stress-induced corticosterone release but were associated with changes in CRH receptor type 1 expression. Furthermore, the despair-like changes were normalized with antidepressant treatment. Overall, these studies suggest that forebrain-restricted CRH signaling during development can permanently alter stress adaptation leading to increases in maladaptive behavior in adulthood.
Loss of α7 Nicotinic Receptors Enhances β-Amyloid Oligomer Accumulation, Exacerbating Early-Stage Cognitive Decline and Septohippocampal Pathology in a Mouse Model of Alzheimer's Disease
Authors: Hernandez Caterina M. , Kayed Rakez , Zheng Hui , Sweatt J. David , Dineley Kelly T.
Published: February 2010

Early Alzheimer's disease (AD) is marked by cholinergic hypofunction, neuronal marker loss, and decreased nicotinic acetylcholine receptor (nAChR) density from the cortex and hippocampus. α7 nAChRs expressed on cholinergic projection neurons and target regions have been implicated in neuroprotection against β-amyloid (Aβ) toxicity and maintenance of the septohippocampal phenotype. We tested the role that α7 nAChRs perform in the etiology of early AD by genetically deleting the α7 nAChR subunit from the Tg2576 mouse model for AD and assessing animals for cognitive function and septohippocampal integrity. Thus, Tg2576 mice transgenic for mutant human amyloid precursor protein (APP) were crossed with α7 nAChR knock-out mice (A7KO) to render an animal with elevated Aβ in the absence of α7 nAChRs (A7KO–APP). We found that learning and memory deficits seen in 5-month-old APP mice are more severe in the A7KO–APP animals. Analyses of animals in early-stage preplaque cognitive decline revealed signs of neurodegeneration in A7KO–APP hippocampus as well as loss of cholinergic functionality in the basal forebrain and hippocampus. These changes occurred concomitant with the appearance of a dodecameric oligomer of Aβ that was absent from all other genotypic groups, generating the hypothesis that increased soluble oligomeric Aβ may underlie additional impairment of A7KO–APP cognitive function. Thus, α7 nAChRs in a mouse model for early-stage AD appear to serve a neuroprotective role through maintenance of the septohippocampal cholinergic phenotype and preservation of hippocampal integrity possibly through influences on Aβ accumulation and oligomerization.
Suppression of the Intrinsic Apoptosis Pathway by Synaptic Activity
Authors: Léveillé Frédéric , Papadia Sofia , Fricker Michael , Bell Karen F. S. , Soriano Francesc X. , Martel Marc-André , Puddifoot Clare , Habel Marlen , Wyllie David J. , Ikonomidou Chrysanthy , Tolkovsky Aviva M. , Hardingham Giles E.
Published: February 2010

Synaptic activity promotes resistance to diverse apoptotic insults, the mechanism behind which is incompletely understood. We show here that a coordinated downregulation of core components of the intrinsic apoptosis pathway by neuronal activity forms a key part of the underlying mechanism. Activity-dependent protection against apoptotic insults is associated with inhibition of cytochromecrelease in most but not all neurons, indicative of anti-apoptotic signaling both upstream and downstream of this step. We find that enhanced firing activity suppresses expression of the proapoptotic BH3-only member genePumain a NMDA receptor-dependent, p53-independent manner. Puma expression is sufficient to induce cytochromecloss and neuronal apoptosis. Puma deficiency protects neurons against apoptosis and also occludes the protective effect of synaptic activity, while blockade of physiological NMDA receptor activity in the developing mouse brain induces neuronal apoptosis that is preceded by upregulation of Puma. However, enhanced activity can also confer resistance to Puma-induced apoptosis, acting downstream of cytochromecrelease. This mechanism is mediated by transcriptional suppression of apoptosome components Apaf-1 and procaspase-9, and limiting caspase-9 activity, since overexpression of procaspase-9 accelerates the rate of apoptosis in active neurons back to control levels. Synaptic activity does not exert further significant anti-apoptotic effects downstream of caspase-9 activation, since an inducible form of caspase-9 overrides the protective effect of synaptic activity, despite activity-induced transcriptional suppression of caspase-3. Thus, suppression of apoptotic gene expression may synergize with other activity-dependent events such as enhancement of antioxidant defenses to promote neuronal survival.
Organization of Myelinated Axons by Caspr and Caspr2 Requires the Cytoskeletal Adapter Protein 4.1B
Authors: Horresh Ido , Bar Vered , Kissil Joseph L. , Peles Elior
Published: February 2010

Caspr and Caspr2 regulate the formation of distinct axonal domains around the nodes of Ranvier. Caspr is required for the generation of a membrane barrier at the paranodal junction (PNJ), whereas Caspr2 serves as a membrane scaffold that clusters Kv1 channels at the juxtaparanodal region (JXP). Both Caspr and Caspr2 interact with protein 4.1B, which may link the paranodal and juxtaparanodal adhesion complexes to the axonal cytoskeleton. To determine the role of protein 4.1B in the function of Caspr proteins, we examined the ability of transgenic Caspr and Caspr2 mutants lacking their 4.1-binding sequence (d4.1) to restore Kv1 channel clustering inCaspr- andCaspr2-null mice, respectively. We found that Caspr-d4.1 was localized to the PNJ and is able to recruit the paranodal adhesion complex components contactin and NF155 to this site. Nevertheless, in axons expressing Caspr-d4.1, Kv1 channels were often detected at paranodes, suggesting that the interaction of Caspr with protein 4.1B is necessary for the generation of an efficient membrane barrier at the PNJ. We also found that the Caspr2-d4.1 transgene did not accumulate at the JXP, even though it was targeted to the axon, demonstrating that the interaction with protein 4.1B is required for the accumulation of Caspr2 and Kv1 channels at the juxtaparanodal axonal membrane. In accordance, we show that Caspr2 and Kv1 channels are not clustered at the JXP in4.1B-null mice. Our results thus underscore the functional importance of protein 4.1B in the organization of peripheral myelinated axons.
Alternative Splicing of the Histone Demethylase LSD1/KDM1 Contributes to the Modulation of Neurite Morphogenesis in the Mammalian Nervous System
Authors: Zibetti Cristina , Adamo Antonio , Binda Claudia , Forneris Federico , Toffolo Emanuela , Verpelli Chiara , Ginelli Enrico , Mattevi Andrea , Sala Carlo , Battaglioli Elena
Published: February 2010

A variety of chromatin remodeling complexes are thought to orchestrate transcriptional programs that lead neuronal precursors from earliest commitment to terminal differentiation. Here we show that mammalian neurons have a specialized chromatin remodeling enzyme arising from a neurospecific splice variant of LSD1/KDM1, histone lysine specific demethylase 1, whose demethylase activity on Lys4 of histone H3 has been related to gene repression. We found that alternative splicing of LSD1 transcript generates four full-length isoforms from combinatorial retention of two identified exons: the 4 aa exon E8a is internal to the amine oxidase domain, and its inclusion is restricted to the nervous system. Remarkably, the expression of LSD1 splice variants is dynamically regulated throughout cortical development, particularly during perinatal stages, with a progressive increase of LSD1 neurospecific isoforms over the ubiquitous ones. Notably, the same LSD1 splice dynamics can be fairly recapitulated in cultured cortical neurons. Functionally, LSD1 isoforms displayin vitroa comparable demethylase activity, yet the inclusion of the sole exon E8a reduces LSD1 repressor activity on a reporter gene. Additional distinction among isoforms is supported by the knockdown of neurospecific variants in cortical neurons resulting in the inhibition of neurite maturation, whereas overexpression of the same variants enhances it. Instead, perturbation of LSD1 isoforms that are devoid of the neurospecific exon elicits no morphogenic effect. Collectively, results demonstrate that the arousal of neuronal LSD1 isoforms pacemakes early neurite morphogenesis, conferring a neurospecific function to LSD1 epigenetic activity.
Neuronal Nitric Oxide Synthase Alteration Accounts for the Role of 5-HT1AReceptor in Modulating Anxiety-Related Behaviors
Authors: Zhang Jing , Huang Xin-Yan , Ye Min-Li , Luo Chun-Xia , Wu Hai-Yin , Hu Yao , Zhou Qi-Gang , Wu Dan-Lian , Zhu Li-Juan , Zhu Dong-Ya
Published: February 2010

Increasing evidence suggests that 5-HT1Areceptor (5-HT1AR) is implicated in anxiety disorders. However, the mechanism underlying the role of 5-HT1AR in these diseases remains unknown. Here, we show that 5-HT1AR-selective agonist 8-OH-DPAT and selective serotonin reuptake inhibitor (SSRI) fluoxetine downregulated hippocampal neuronal nitric oxide synthase (nNOS) expression, whereas 5-HT1AR-selective antagonist NAN-190 upregulated hippocampal nNOS expression. By assessing anxiety-related behaviors using the novelty suppressed feeding, open-field, and elevated plus maze tests, we show that mice lacking nNOS gene [knock-out (KO)] or treated with nNOS-selective inhibitor 7-nitroindazole (7-NI; i.p., 30 mg/kg/d for 28 d; or intrahippocampal microinjection, 16.31 μg/1.0 μl) displayed an anxiolytic-like phenotype, implicating nNOS in anxiety. We also show that, in wild-type (WT) mice, administrations of 8-OH-DPAT (i.p., 0.1 mg/kg/d) or fluoxetine (i.p., 10 mg/kg/d) for 28 d caused anxiolytic-like effects, whereas NAN-190 (i.p., 0.3 mg/kg/d for 28 d) caused anxiogenic-like effects. In KO mice, however, these drugs were ineffective. Moreover, intrahippocampal infusion of 8-OH-DPAT (45.963 μg/100 μl) using 14 d osmotic minipump produced anxiolytic effects. Intrahippocampal microinjection of 7-NI (16.31 μg/1.0 μl) abolished the anxiogenic-like effects of intrahippocampal NAN-190 (4.74 μg/1.0 μl). Additionally, NAN-190 decreased and 8-OH-DPAT increased phosphorylated cAMP response element-binding protein (CREB) levels in WT mice but not in KO mice. Blockade of hippocampal CREB phosphorylation by microinjection of H89 (5.19 μg/1.0 μl), a PKA (protein kinase A) inhibitor, abolished the anxiolytic-like effects of 7-NI (i.p., 30 mg/kg/d for 21 d). These findings indicate that both hippocampal nNOS and CREB activity mediate the anxiolytic effects of 5-HT1AR agonists and SSRIs.
Deletion of GRK1 Causes Retina Degeneration through a Transducin-Independent Mechanism
Authors: Fan Jie , Sakurai Keisuke , Chen Ching-Kang , Rohrer Baerbel , Wu Bill X. , Yau King-Wai , Kefalov Vladimir , Crouch Rosalie K.
Published: February 2010

Rpe65−/−mice are unable to produce 11-cis-retinal, the chromophore of visual pigments. Consequently, the pigment is present as the apoprotein opsin with a minute level of pigment containing 9-cis-retinal as chromophore. Notably, a 10–20% fraction of this opsin is mono-phosphorylated independently of light conditions. To determine the role of rhodopsin kinase (GRK1) in phosphorylating this opsin and to test whether eliminating this phosphorylation would accelerate photoreceptor degeneration, we generated theRpe65−/−Grk1−/−mouse. The retinae ofRpe65−/−Grk1−/−mice had negligible opsin phosphorylation, extensive degeneration with decreased opsin levels, and diminished light-evoked rod responses relative toRpe65−/−mice. These data show that opsin phosphorylation in theRpe65−/−mouse is due to the action of GRK1 and is neuroprotective. However, despite the higher activity of unphosphorylated opsin, the severe loss of opsin in the rapidly degeneratingRpe65−/−Grk1−/−mice resulted in lower overall opsin activity and in higher rod sensitivity compared withRpe65−/−mice. InRpe65−/−Grk1−/−Gnat1−/−mice where transduction activation was blocked, degeneration was only partially prevented. Therefore, increased opsin activity in the absence of phosphorylation was not the only mechanism for the accelerated retinal degeneration. Finally, the deletion of GRK1 triggered retinal degeneration inGrk1−/−mice after 1 month, even in the absence of apo-opsin. This degeneration was independent of light conditions and occurred even in the absence of transducin inGrk1−/−Gnat1−/−mice. Taken together, our results demonstrate a light-independent mechanism for retinal degeneration in the absence of GRK1, suggesting a second, not previously recognized role for that kinase.
Premolded Bovine Pericardial Chords for Replacement of Ruptured or Elongated Chordae Tendineae
Authors: Gregori Francisco , Leal Jo�o Carlos , Braile Domingo Marcolino
Published: February 2010

Background: The aim of this study was to assess by Doppler echocardiography (ECO) the functioning of the mitral valve apparatus in patients who have undergone implantation of standardized bovine pericardium chordae (SBPC) for replacement of ruptured or elongated chordae tendineae with significant thinning.Methods: SBPC were implanted in 31 patients who had mitral insufficiency due to rupture of chordae tendinae or elongated chordae with significant thinning. Patient ages ranged from 19 to 85 years (mean of 58 years). The most frequent cause of mitral insufficiency was fibroelastic degeneration in 25 patients (80.6%). The SBPC were fashioned as a set, joined at their extremities by 2 polyester-reinforced rods forming a monobloc. The SBPC were 2-mm wide and were positioned parallel to one another at a distance of 3 mm. Each set of SBPC had a corresponding measurer, and their length ranged from 20 to 35 mm. In 21 patients (67.7%) the SBPC were implanted in the posterior leaflet and in 10 patients (32.3%) in the anterior leaflet (in 2 patients concurrently in the anterior and posterior leaflets). All patients were assessed by ECO postoperatively, with a 20-month mean follow-up time (range 6-45 months).Results: One patient (3.2%) died of pulmonary embolism during the early postoperative period. Postoperative ECO showed absence of mitral regurgitation in 17 patients (54.8%), mild regurgitation in 9 (29.0%), and mild-to-moderate regurgitation in 4 (12.9%). Opening and mobility of the mitral valve were normal in the 30 surviving patients.Conclusion: The ECO revealed good functionality of the mitral valve apparatus with appropriate leaflet coaptation in patients who had undergone implantation of SBPC for replacement of ruptured or elongated and thinned chordae. A longer follow-up is required to assess absence of calcification and/or degeneration of the SBPC.
Overestimation of the Operative Risk by the EuroSCORE Also in High-Risk Patients Undergoing Aortic Valve Replacement with a Stentless Biological Prosthesis
Authors: Holinski Sebastian , Claus Benjamin , Christ Torsten , Kasperiunaite Ruta , Konertz Wolfgang
Published: February 2010

Background: The EuroSCORE generally overestimates the risk of standard aortic valve replacement (AVR). The predictive value of this risk algorithm for high-risk patients undergoing stentless AVR is unclear; therefore, we compared the EuroSCORE prediction with our results in this patient population.Methods: One hundred thirty-two patients with a logistic EuroSCORE of at least 10 (mean, 25) underwent primary isolated AVR with a stentless bioprosthesis between January 2004 and December 2007. Seventy-one patients (54%) were octogenarians or nonagenarians, 62 (47%) had a reduced left ventricular ejection fraction, and 46 (35%) had an extracardiac arteriopathy.Results: Maximum/mean pressure gradients for the implanted valve prostheses were 19/11 mm Hg, and the mean regurgitation grade was 0.06. Stroke occurred in 3% of the patients, and a permanent pacemaker was required in 3%. The 30-day mortality rate was 8%. Another 5% of the patients died after the 30th postoperative day but within the same hospital admission. The predicted mortality was almost 100% greater than the observed mortality.Conclusion: We observed a mortality rate that was 50% lower than that predicted by the logistic EuroSCORE. Therefore, one should not hesitate to use stentless valves in highrisk patients because the EuroSCORE greatly overestimates their surgical risk.
Intra-atrial Placement of a Mitral Prosthesis in a Patient with Severe Mitral Annulus Calcification: A Case Report
Authors: Santana Orlando , Lamelas Joseph
Published: February 2010

An 88-year-old woman presented with increasing dyspnea and angina. She was found to have severe aortic stenosis, 2-vessel coronary artery disease, and severe mitral regurgitation. During surgery the patient was noted to have such severe mitral annular calcification that performing a conventional mitral valve replacement would have significantly increased the operative risk. Instead, an 8-mm Dacron graft was sutured onto the sewing cuff of a reversed 23-mm Mosaic porcine aortic valve (Medtronic, Minneapolis, MN, USA). The Dacron graft was then sutured to the left atrial wall surrounding the calcified mitral annulus. A bioprosthetic aortic valve replacement, along with a 2-vessel coronary artery bypass procedure, was also performed.
Lower Perfusion Pressure during Hypothermic Cardiopulmonary Bypass Is Associated with Decreased Cerebral Blood Flow and Impaired Memory Performance 6 Months Postoperatively
Authors: Paolin Adolfo , Michielon Paolo , Betetto Michele , Sartori Giuseppe , Valfr� Carlo , Rodriguez Guido , Murkin John M.
Published: February 2010

Objectives: We undertook to determine the influence of perfusion pressure during hypothermic cardiopulmonary bypass (CPB) on cerebral blood flow (CBF) and cognitive memory outcome at 6 months postoperatively.Methods: Nineteen patients who underwent hypothermic nonpulsatile CPB for elective coronary artery bypass (CAB) surgery were evaluated by 133Xe measurement of the CBF and by the Incidental Memory Assessment for evaluating cognitive memory (IMTscore), both at baseline before the operation (T1) and again at 5 to 6 months postoperatively (T2).Results: Overall, the mean CBF fell significantly from 39 5 mL(100 g)-1min-1 at T1 to 33 3 mL(100 g)-1min-1 at T2 (P < .001). The decrease in CBF from T1 to T2 (CBF2-1) correlated with a significant reduction in the IMTscore from T1 to T2 (IMTscore2-1) (P < .001) and with a mean arterial pressure during CPB (MAPCPB) of
Xiphoid Lower-Sternotomy Approach for Multivessel Revascularization of the Left Internal Mammary Artery to the Left Anterior Descending Artery and Right Internal Mammary Artery Inflow to the Other Vessels
Authors: Benetti Federico , Prapas Sotirios , Angeletti Ernesto , Ameriso Jose Luis , Cicalle Eduardo , Klokocovnik Tomislav , Knezevic Ivan , Gersak Borut
Published: February 2010

Background: We describe the technical details and the preliminary results of a new surgical approach for multivessel disease that involves using a lower T sternotomy, grafting of the left internal mammary artery (LIMA) to the left anterior descending coronary artery (LAD) and use of the right internal mammary artery (RIMA) as inflow to the other vessels.Operative Technique: The sternotomy was made from the xiphoid up to the fourth intercostal space and then was continued transversally (T incision). The LIMA was harvested for a length of approximately 8 cm, with preservation of the distal part. The vein was simultaneously taken from the leg. The RIMA was dissected for a length of approximately 5 cm, and the distal part was occluded. Then, 3 mg/kg heparin was given. The anastomosis between the vein and the RIMA was performed. The distal venous anastomoses were done either singly or sequentially. The anterior or posterior route was chosen according to the patient's anatomy. The LIMA was then anastomosed to the LAD. One drain was placed. The sternum was closed with 4 wires, 2 for the T incision and 2 for the sternum.Results: Between September and December 2008, 9 patients underwent their operations with this technique. The mean age was 60 years (range, 55-68 years). The mean number of grafts was 2.8. The mean hospital stay was 5.2 days. Operative mortality was 0%. All patients were reevaluated with 16-slice multislice computed tomography, and all grafts were patent. At the 3-month follow-up, all patients were alive and free of symptoms.Conclusion: This minimally invasive technique is a useful alternative for complete revascularization. The sternal mammary supply and the upper part of the sternum are preserved.
Cardiac Effects of Postconditioning Depend Critically on the Duration of Reperfusion and Reocclusion Episodes
Authors: Pinheiro Bruno Botelho , Fiorelli Alfredo In�cio , Gomes Otoni Moreira , Gersak Borut
Published: February 2010

Objective: The objective of the present study was to evaluate the effects of ischemic postconditioning on left ventricular function in isolated rat hearts.Methods: The hearts of 24 Wistar rats were were isolated, perfused immediately, and distributed into 3 groups: GI, control (n = 8); GII, three 10-second cycles of postconditioning (n = 8); and GIII, three 30-second cycles of postconditioning (n = 8). After a 15-minute stabilization period, all hearts underwent 20 minutes of global ischemia following 20 minutes of reperfusion. At times t0 (control), t5, t10, t15, and t20 (0, 5, 10, 15, and 20 minutes of reperfusion, respectively), we recorded the heart rate, coronary flow, systolic pressure, +(dP/dt)max (maximum speed of increase in the left ventricular pressure), and -(dP/dt)max (maximum speed of decrease in the left ventricular pressure). Data were analyzed by a 1-way analysis of variance, followed by the Tukey test; a P value .05); however, statistically significant differences in +(dP/dt)max between GII and GI and between GII and GIII occurred at t20 (GI, 1409.0 415.1 mm Hg/s; GII, 1917.3 403.0 mm Hg/s; GIII, 1344.8 355.8 mm Hg/s) (GII versus GI, P = .04; GII versus GIII, P = .02).Conclusion: Ischemic postconditioning with three 10-second cycles of reperfusion/reocclusion was demonstrated effective for preserving +(dP/dt)max in isolated rat hearts that underwent 20 minutes of ischemia following 20 minutes of reperfusion.