209 research outputs found

    Examining the reversibility of long-term behavioral disruptions in progeny of maternal SSRI exposure

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    Serotonergic dysregulation is implicated in numerous psychiatric disorders. Serotonin plays widespread trophic roles during neurodevelopment; thus perturbations to this system during development may increase risk for neurodevelopmental disorders. Epidemiological studies have examined association between selective serotonin reuptake inhibitor (SSRI) treatment during pregnancy and increased autism spectrum disorder (ASD) risk in offspring. It is unclear from these studies whether ASD susceptibility is purely related to maternal psychiatric diagnosis, or if treatment poses additional risk. We sought to determine whether maternal SSRI treatment alone or in combination with genetically vulnerable background was sufficient to induce offspring behavior disruptions relevant to ASD. We exposed C57BL/6J or Celf6(+/-) mouse dams to fluoxetine (FLX) during different periods of gestation and lactation and characterized offspring on tasks assessing social communicative interaction and repetitive behavior patterns including sensory sensitivities. We demonstrate robust reductions in pup ultrasonic vocalizations (USVs) and alterations in social hierarchy behaviors, as well as perseverative behaviors and tactile hypersensitivity. Celf6 mutant mice demonstrate social communicative deficits and perseverative behaviors, without further interaction with FLX. FLX re-exposure in adulthood ameliorates the tactile hypersensitivity yet exacerbates the dominance phenotype. This suggests acute deficiencies in serotonin levels likely underlie the abnormal responses to sensory stimuli, while the social alterations are instead due to altered development of social circuits. These findings indicate maternal FLX treatment, independent of maternal stress, can induce behavioral disruptions in mammalian offspring, thus contributing to our understanding of the developmental role of the serotonin system and the possible risks to offspring of SSRI treatment during pregnancy

    Appropriate Timing of Fluoxetine and Statin Delivery Reduces the Risk of Secondary Bleeding in Ischemic Stroke Rats

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    Background: Ongoing clinical trials are testing the effect of fluoxetine delivered post-stroke where a majority of patients are taking statins. This study determined the influence of the timing of administration of fluoxetine and statin on the final infarct volume and the risk of secondary bleeding in an animal model of ischemic stroke. Methods and findings: Ischemic strokes were induced by endothelin-1 injection into two cortical sites of 10-12 month old female rats, targeting the forelimb motor cortex. Combined medications (5 mg/kg fluoxetine and 1 mg/kg simvastatin) were orally administered either beginning 6-12 hours or 20-26 hours after stroke induction and continued daily for 90 days. Infarct volumes were assessed at poststroke day 91 using Nissl stained coronal brain sections. Control animals typically had 5-13 mm3 infarct volumes following endothelin-1 induced stroke. Animals that received fluoxetine and simvastatin (FS) beginning 20- 26 hours after stroke induction showed a strong trend of reduced infarct volume (3±0.3447 mm3 SEM, P=0.0563). Earlier drug delivery (6-12 hours after stroke) resulted in significantly larger infarct volumes (15.44.260 mm3 SEM, P=0.0157) when the drug groups were directly compared. Examination of the infarcts showed that earlier drug delivery induced secondary hemorrhagic infarcts, while later delivery did not (P=0.0427; Fisher’s exact test). Conclusion: There is a danger of secondary bleeding if fluoxetine and simvastatin are combined within 6-12 hours of ischemic stroke induction in rats resulting in larger infarct volumes. Delaying fluoxetine and simvastatin delivery to 20-26 hours after stroke induction in rats, however, reduces infarct volume and significantly lowers the risk of secondary hemorrhagic infarcts

    Ambiguity, multiple streams, and EU policy

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    The multiple streams framework draws insight from interactions between agency and institutions to explore the impact of context, time, and meaning on policy change and to assess the institutional and issue complexities permeating the European Union (EU) policy process. The authors specify the assumptions and structure of the framework and review studies that have adapted it to reflect more fully EU decision-making processes. The nature of policy entrepreneurship and policy windows are assessed to identify areas of improvement. Finally, the authors sketch out a research agenda that refines the logic of political manipulation which permeates the lens and the institutional complexity which frames the EU policy process

    A 10Gbps optical burst switching network incorporating ultra-fast (5ns) wavelength switched tunable laser sources

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    This paper outlines the development of a prototype optical burst mode switching network based upon a star topology, the ultimate application of which could be as a transparent payload processor onboard satellite repeaters. The network architecture incorporates multiple tunable laser sources, burst mode receivers and a passive optical router (Arrayed Waveguide Grating). Each tunable optical signal should carry ≄10Gbps and be capable of wavelength switching in c. 5ns timescales. Two monolithic tunable laser types, based upon different technologies, will be utilised: a Slotted Fabry Perot laser (a Fabry Perot laser with slots added in order to introduce controlled cavity perturbations); and a Modulated Grating Y-Branch Laser (MGY: a widely tunable, multi-section device similar to the DBR laser). While the Slotted Fabry Perot laser is expected to achieve the required switching times, it is an immature technology not yet capable of achieving tunability over 80 ITU channels from a single chip. The MGY device is a more mature technology and has full C-band ITU channel coverage, but is not capable of the required short switching times. Hence, in order to facilitate the integration of this more mature technology into the prototype breadboard with the requisite switching time capabilities, a system of ‘dual laser’ transmitters is being developed to enable data transmission from one MGY laser while the other switches and vice-versa. This work is being performed under ESA contract AO 1-5025/06/NL/PM, Optical Technologies for Ultra - fast Processing

    Glycan repositioning of influenza hemagglutinin stem facilitates the elicitation of protective cross-group antibody responses.

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    The conserved hemagglutinin (HA) stem has been a focus of universal influenza vaccine efforts. Influenza A group 1 HA stem-nanoparticles have been demonstrated to confer heterosubtypic protection in animals; however, the protection does not extend to group 2 viruses, due in part to differences in glycosylation between group 1 and 2 stems. Here, we show that introducing the group 2 glycan at Asn38 to a group 1 stem-nanoparticle (gN38 variant) based on A/New Caledonia/20/99 (H1N1) broadens antibody responses to cross-react with group 2 HAs. Immunoglobulins elicited by the gN38 variant provide complete protection against group 2 H7N9 virus infection, while the variant loses protection against a group 1 H5N1 virus. The N38 glycan thus is pivotal in directing antibody responses by controlling access to group-determining stem epitopes. Precise targeting of stem-directed antibody responses to the site of vulnerability by glycan repositioning may be a step towards achieving cross-group influenza protection.We thank D. Scorpio, A. Taylor, H. Bao, C. Chiedi, M. Dillon, L. Gilliam, and G. Sarbador (VRC) for help with animal studies; H. Andersen (Bioqual, Inc.) for mouse challenge studies; C. Case (Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc.) for help with challenge study coordination; A. Kumar (VRC) for producing RSV proteins; and members of Viral Pathogenesis Laboratory and Universal Influenza Vaccine Program (VRC) for helpful discussion. Support for this work was provided by the Intramural Research Program of the Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health. Electron microscopy data collection and analyses were funded by federal funds from the Frederick National Laboratory for Cancer Research, National Institutes of Health, under contract number HHSN261200800001E, and by Leidos Biomedical Research, Inc. (Y.T. and T.S.)

    Mutation in the xpsD gene of Xanthomonas axonopodis pv. citri affects cellulose degradation and virulence

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    The Gram-negative bacterium Xanthomonas axonopodis pv. citri, the causal agent of citrus canker, is a major threat to the citrus industry worldwide. Although this is a leaf spot pathogen, it bears genes highly related to degradation of plant cell walls, which are typically found in plant pathogens that cause symptoms of tissue maceration. Little is known on Xac capacity to cause disease and hydrolyze cellulose. We investigated the contribution of various open reading frames on degradation of a cellulose compound by means of a global mutational assay to selectively screen for a defect in carboxymethyl cellulase (CMCase) secretion in X. axonopodis pv. citri. Screening on CMC agar revealed one mutant clone defective in extracellular glycanase activity, out of nearly 3,000 clones. The insertion was located in the xpsD gene, a component of the type II secretion system (T2SS) showing an influence in the ability of Xac to colonize tissues and hydrolyze cellulose. In summary, these data show for the first time, that X. axonopodis pv. citri is capable of hydrolyzing cellulose in a T2SS-dependent process. Furthermore, it was demonstrated that the ability to degrade cellulose contributes to the infection process as a whole

    Molecular epidemiology, drug susceptibility and economic aspects of tuberculosis in mubende district, Uganda

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    <div><p>Background</p><p>Tuberculosis (TB) remains a global public health problem whose effects have major impact in developing countries like Uganda. This study aimed at investigating genotypic characteristics and drug resistance profiles of <i>Mycobacterium tuberculosis</i> isolated from suspected TB patients. Furthermore, risk factors and economic burdens that could affect the current control strategies were studied.</p><p>Methods</p><p>TB suspected patients were examined in a cross-sectional study at the Mubende regional referral hospital between February and July 2011. A questionnaire was administered to each patient to obtain information associated with TB prevalence. Isolates of <i>M. tuberculosis</i> recovered during sampling were examined for drug resistance to first line anti-TB drugs using the BACTEC-MGIT960<sup>TM</sup>system. All isolates were further characterized using deletion analysis, spoligotyping and MIRU-VNTR analysis. Data were analyzed using different software; MIRU-VNTR <i>plus</i>, SITVITWEB, BioNumerics and multivariable regression models.</p><p>Results</p><p><i>M. tuberculosis</i> was isolated from 74 out of 344 patients, 48 of these were co-infected with HIV. Results from the questionnaire showed that previously treated TB, co-infection with HIV, cigarette smoking, and overcrowding were risk factors associated with TB, while high medical related transport bills were identified as an economic burden. Out of the 67 isolates that gave interpretable results, 23 different spoligopatterns were detected, nine of which were novel patterns. T2 with the sub types Uganda-I and Uganda-II was the most predominant lineage detected. Antibiotic resistance was detected in 19% and multidrug resistance was detected in 3% of the isolates.</p><p>Conclusion</p><p>The study detected <i>M. tuberculosis</i> from 21% of examined TB patients, 62% of whom were also HIV positive. There is a heterogeneous pool of genotypes that circulate in this area, with the T2 lineage being the most predominant. High medical related transport bills and drug resistance could undermine the usefulness of the current TB strategic interventions.</p></div

    Design of Nanoparticulate Group 2 Influenza Virus Hemagglutinin Stem Antigens That Activate Unmutated Ancestor B Cell Receptors of Broadly Neutralizing Antibody Lineages.

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    Influenza vaccines targeting the highly conserved stem of the hemagglutinin (HA) surface glycoprotein have the potential to protect against pandemic and drifted seasonal influenza viruses not covered by current vaccines. While HA stem-based immunogens derived from group 1 influenza A viruses have been shown to induce intragroup heterosubtypic protection, HA stem-specific antibody lineages originating from group 2 may be more likely to possess broad cross-group reactivity. We report the structure-guided development of mammalian-cell-expressed candidate vaccine immunogens based on influenza A virus group 2 H3 and H7 HA stem trimers displayed on self-assembling ferritin nanoparticles using an iterative, multipronged approach involving helix stabilization, loop optimization, disulfide bond addition, and side-chain repacking. These immunogens were thermostable, formed uniform and symmetric nanoparticles, were recognized by cross-group-reactive broadly neutralizing antibodies (bNAbs) with nanomolar affinity, and elicited protective, homosubtypic antibodies in mice. Importantly, several immunogens were able to activate B cells expressing inferred unmutated common ancestor (UCA) versions of cross-group-reactive human bNAbs from two multidonor classes, suggesting they could initiate elicitation of these bNAbs in humans. Current influenza vaccines are primarily strain specific, requiring annual updates, and offer minimal protection against drifted seasonal or pandemic strains. The highly conserved stem region of hemagglutinin (HA) of group 2 influenza A virus subtypes is a promising target for vaccine elicitation of broad cross-group protection against divergent strains. We used structure-guided protein engineering employing multiple protein stabilization methods simultaneously to develop group 2 HA stem-based candidate influenza A virus immunogens displayed as trimers on self-assembling nanoparticles. Characterization of antigenicity, thermostability, and particle formation confirmed structural integrity. Group 2 HA stem antigen designs were identified that, when displayed on ferritin nanoparticles, activated B cells expressing inferred unmutated common ancestor (UCA) versions of human antibody lineages associated with cross-group-reactive, broadly neutralizing antibodies (bNAbs). Immunization of mice led to protection against a lethal homosubtypic influenza virus challenge. These candidate vaccines are now being manufactured for clinical evaluation
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