228 research outputs found

    Cortical oscillatory dynamics and benzodiazepine-site modulation of tonic inhibition in fast spiking interneurons

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    Tonic conductance mediated by extrasynaptic GABAA receptors has been implicated in the modulation of network oscillatory activity. Using an in vitro brain slice to produce oscillatory activity and a kinetic model of GABAA receptor dynamics, we show that changes in tonic inhibitory input to fast spiking interneurons underlie benzodiazepine-site mediated modulation of neuronal network synchrony in rat primary motor cortex. We found that low concentrations (10 nM) of the benzodiazepine site agonist, zolpidem, reduced the power of pharmacologically-induced beta-frequency (15-30 Hz) oscillatory activity. By contrast, higher doses augmented beta power. Application of the antagonist, flumazenil, also increased beta power suggesting endogenous modulation of the benzodiazepine binding site. Voltage-clamp experiments revealed that pharmacologically-induced rhythmic inhibitory postsynaptic currents were reduced by 10 nM zolpidem, suggesting an action on inhibitory interneurons. Further voltage-clamp studies of fast spiking cells showed that 10 nM zolpidem augmented a tonic inhibitory GABAA receptor mediated current in fast spiking cells whilst higher concentrations of zolpidem reduced the tonic current. A kinetic model of zolpidem-sensitive GABAA receptors suggested that incubation with 10 nM zolpidem resulted in a high proportion of GABAA receptors locked in a kinetically slow desensitized state whilst 30 nM zolpidem favoured rapid transition into and out of desensitized states. This was confirmed experimentally using a challenge with saturating concentrations of GABA. Selective modulation of an interneuron-specific tonic current may underlie the reversal of cognitive and motor deficits afforded by low-dose zolpidem in neuropathological states

    The CatWISE Preliminary Catalog: Motions from WISE and NEOWISE Data

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    CatWISE is a program to catalog sources selected from combined WISE and NEOWISE all-sky survey data at 3.4 and 4.6 Ī¼m (W1 and W2). The CatWISE Preliminary Catalog consists of 900,849,014 sources measured in data collected from 2010 to 2016. This data set represents four times as many exposures and spans over 10 times as large a time baseline as that used for the AllWISE Catalog. CatWISE adapts AllWISE software to measure the sources in coadded images created from six-month subsets of these data, each representing one coverage of the inertial sky, or epoch. The catalog includes the measured motion of sources in eight epochs over the 6.5 yr span of the data. From comparison to Spitzer, signal-to-noise ratio = 5 limits in magnitudes in the Vega system are W1 = 17.67 and W2 = 16.47, compared to W1 = 16.96 and W2 = 16.02 for AllWISE. From comparison to Gaia, CatWISE positions have typical accuracies of 50 mas for stars at W1 = 10 mag and 275 mas for stars at W1 = 15.5 mag. Proper motions have typical accuracies of 10 mas yrā»Ā¹ and 30 mas yrā»Ā¹ for stars with these brightnesses, an order of magnitude better than from AllWISE. The catalog is available in the WISE/NEOWISE Enhanced and Contributed Products area of the NASA/IPAC Infrared Science Archive

    Women's experiences of ovulation testing: A qualitative analysis

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    Ā© 2015 Jones et al.Background: The introduction of home digital ovulation tests (OTs) has provided a simple solution for women wishing to optimise the timing of intercourse when trying to conceive. However, despite this, very little is understood about women's experiences of using these tests. Methods: We carried out qualitative, semi-structured telephone interviews with women who were seeking to conceive (not actively undergoing clinical investigation/fertility treatment) from the general UK population. The interviews were conducted following participation in a randomised controlled trial (RCT) in which participants were either provided with digital home OTs to assist in timing intercourse (n = 18) or advised to have intercourse every 2-3 days (n = 18). The interviews were digitally recorded, transcribed and then analysed using Framework analysis to identify the themes. Results: Data saturation was reached after 36 interviews. The use of the OT appeared to elicit 10 key themes, which could be described within the context of three overarching issues: 1) a positive impact (understanding the menstrual cycle, confirming when ovulating, emotional support, improving the relationship), 2) a negative impact (changing sex life and relationship with their partner, the emotional consequences of prolonged use, questions and uncertainty about what their results mean for them) and 3) the experiences of trying to conceive in general (use of clinical guidance and emotional experience). Conclusions: Overall, the use of home OTs were found to affect women's thoughts and feelings in multiple ways during attempts to conceive. Although some women reported a range of negative experiences when using OTs, they also reported similar negative experiences when trying to conceive without using the tests. However, there were many positive themes associated with OT use, including an increased understanding of the menstrual cycle, confirmation of ovulation timing and providing a source of help and support when trying to conceive. Overall, when women are trying to conceive, ensuring they have access to high-quality information, including use of OT, may be of benefit to help address some of the questions and uncertainties that were raised by the participants in this study. Trial registration number: NCT01084304

    Asynchronous Antarctic and Greenland ice-volume contributions to the last interglacial sea-level highstand

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    The last interglacial (LIG; ~130 to ~118 thousand years ago, ka) was the last time global sea level rose well above the present level. Greenland Ice Sheet (GrIS) contributions were insufficient to explain the highstand, so that substantial Antarctic Ice Sheet (AIS) reduction is implied. However, the nature and drivers of GrIS and AIS reductions remain enigmatic, even though they may be critical for understanding future sea-level rise. Here we complement existing records with new data, and reveal that the LIG contained an AIS-derived highstand from ~129.5 to ~125 ka, a lowstand centred on 125ā€“124 ka, and joint AIS + GrIS contributions from ~123.5 to ~118 ka. Moreover, a dual substructure within the first highstand suggests temporal variability in the AIS contributions. Implied rates of sea-level rise are high (up to several meters per century; m cāˆ’1), and lend credibility to high rates inferred by ice modelling under certain ice-shelf instability parameterisations

    Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop

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    <p>Abstract</p> <p>Background</p> <p>Envenomation by crotaline snakes (rattlesnake, cottonmouth, copperhead) is a complex, potentially lethal condition affecting thousands of people in the United States each year. Treatment of crotaline envenomation is not standardized, and significant variation in practice exists.</p> <p>Methods</p> <p>A geographically diverse panel of experts was convened for the purpose of deriving an evidence-informed unified treatment algorithm. Research staff analyzed the extant medical literature and performed targeted analyses of existing databases to inform specific clinical decisions. A trained external facilitator used modified Delphi and structured consensus methodology to achieve consensus on the final treatment algorithm.</p> <p>Results</p> <p>A unified treatment algorithm was produced and endorsed by all nine expert panel members. This algorithm provides guidance about clinical and laboratory observations, indications for and dosing of antivenom, adjunctive therapies, post-stabilization care, and management of complications from envenomation and therapy.</p> <p>Conclusions</p> <p>Clinical manifestations and ideal treatment of crotaline snakebite differ greatly, and can result in severe complications. Using a modified Delphi method, we provide evidence-informed treatment guidelines in an attempt to reduce variation in care and possibly improve clinical outcomes.</p

    Complications associated with transobturator sling procedures: analysis of 233 consecutive cases with a 27 months follow-up

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    <p>Abstract</p> <p>Backround</p> <p>The transobturator tape procedure (TOT) is an effective surgical treatment of female stress urinary incontinence. However data concerning safety are rare, follow-up is often less than two years, and complications are probably underreported. The aim of this study was to describe early and late complications associated with TOT procedures and identify risk factors for erosions.</p> <p>Methods</p> <p>It was a 27 months follow-up of a cohort of 233 women who underwent TOT with three different types of slings (Aris<sup>Ā®</sup>, Obtape<sup>Ā®</sup>, TVT-O<sup>Ā®</sup>). Follow-up information was available for 225 (96.6%) women.</p> <p>Results</p> <p>There were few per operative complications. Forty-eight women (21.3%) reported late complications including <it>de novo </it>or worsening of preexisting urgencies (10.2%), perineal pain (2.2%), <it>de novo </it>dyspareunia (9%), and vaginal erosion (7.6%). The risk of erosion significantly differed between the three types of slings and was 4%, 17% and 0% for Aris<sup>Ā®</sup>, Obtape<sup>Ā® </sup>and TVT-O<sup>Ā® </sup>respectively (P = 0.001). The overall proportion of women satisfied by the procedure was 72.1%. The percentage of women satisfied was significantly lower in women who experienced erosion (29.4%) compared to women who did not (78.4%) (RR 0.14, 95% CI 0.05-0.38, P < 0.001).</p> <p>Conclusion</p> <p>Late post operative complications are relatively frequent after TOT and can impair patient's satisfaction. Women should be informed of these potential complications preoperatively and require careful follow-up after the procedure. Choice of the safest sling material is crucial as it is a risk factor for erosion.</p

    The effect of sepsis and its inflammatory response on mechanical clot characteristics: a prospective observational study

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    Purpose: Sepsis and its progression are known to have a major influence on the coagulation system. Current coagulation tests are of limited use when assessing coagulation in sepsis patients. This study aims to assess the potential for a new functional biomarker of clot microstructure, fractal dimension, to identify changes in the mechanical properties of clot microstructure across the sepsis spectrum (sepsis, severe sepsis and septic shock). Methods: A total of 100 patients that presented acutely to a large teaching hospital were included in this prospective observational study (50 sepsis, 20 severe sepsis and 30 septic shock) against a matched control of 44 healthy volunteers. Fractal analysis was performed, as well as standard markers of coagulation, and six plasma markers of inflammation. Results: Fractal dimension was significantly higher in the sepsis and severe sepsis groups than the healthy control (1.78 Ā± 0.07 and 1.80 Ā± 0.05 respectively vs 1.74 Ā± 0.03) (p < 0.001), indicating a significant increase in mechanical clot strength and elasticity consistent with a hypercoagulable state. Conversely, fractal dimension was significantly lower in septic shock (1.66 Ā± 0.10, p < 0.001), indicating a significant reduction in mechanical clot strength and functionality consistent with a hypocoagulable state. This corresponded with a significant increase in the inflammatory response. Conclusions: This study confirms that clot microstructure is significantly altered through the various stages of sepsis. Of particular importance was the marked change in clot development between severe sepsis and septic shock, which has not been previously reported

    Increased autophagy in EphrinB2-deficient osteocytes is associated with elevated secondary mineralization and brittle bone

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    Mineralized bone forms when collagen-containing osteoid accrues mineral crystals. This is initiated rapidly (primary mineralization), and continues slowly (secondary mineralization) until bone is remodeled. The interconnected osteocyte network within the bone matrix differentiates from bone-forming osteoblasts; although osteoblast differentiation requires EphrinB2, osteocytes retain its expression. Here we report brittle bones in mice with osteocyte-targeted EphrinB2 deletion. This is not caused by low bone mass, but by defective bone material. While osteoid mineralization is initiated at normal rate, mineral accrual is accelerated, indicating that EphrinB2 in osteocytes limits mineral accumulation. No known regulators of mineralization are modified in the brittle cortical bone but a cluster of autophagy-associated genes are dysregulated. EphrinB2-deficient osteocytes displayed more autophagosomes in vivo and in vitro, and EphrinB2-Fc treatment suppresses autophagy in a RhoA-ROCK dependent manner. We conclude that secondary mineralization involves EphrinB2-RhoA-limited autophagy in osteocytes, and disruption leads to a bone fragility independent of bone mass

    Womenā€™s responses to changes in U.S. preventive task forceā€™s mammography screening guidelines: results of focus groups with ethnically diverse women

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    Background: The 2009 U.S. Preventive Services Task Force (USPSTF) changed mammography guidelines to recommend routine biennial screening starting at age 50. This study describes womenā€™s awareness of, attitudes toward, and intention to comply with these new guidelines. Methods: Women ages 40ā€“50 years old were recruited from the Boston area to participate in focus groups (k = 8; n = 77). Groups were segmented by race/ethnicity (Caucasian = 39%; African American = 35%; Latina = 26%), audio-taped, and transcribed. Thematic content analysis was used. Results: Participants were largely unaware of the revised guidelines and suspicious that it was a cost-savings measure by insurers and/or providers. Most did not intend to comply with the change, viewing screening as obligatory. Few felt prepared to participate in shared decision-making or advocate for their preferences with respect to screening. Conclusions: Communication about the rationale for mammography guideline changes has left many women unconvinced about potential disadvantages or limitations of screening. Since further guideline changes are likely to occur with advances in technology and science, it is important to help women become informed consumers of health information and active participants in shared decision-making with providers. Additional research is needed to determine the impact of the USPSTF change on womenā€™s screening behaviors and on breast cancer outcomes
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