Studies on preconditioning with adenosine, glutamate and ouabain in rat hippocampal slices

Preconditioning is the phenomenon whereby tolerance to lethal insults is induced by exposing the tissue to a prior sublethal stimulus. This exists in several forms, such as ischaemic preconditioning, adenosine preconditioning and excitotoxic preconditioning. Adenosine preconditioning is known to be mediated by activation of A1 receptors and ATP-sensitive potassium channels whilst excitotoxic preconditioning mainly involves stimulation of NMDA receptors, nitric oxide and most likely ATP-sensitive potassium channel activation. ATP-sensitive potassium channel openers such as pinacidil and diazoxide are also known to exert preconditioning against various types of insults. There have been several models of ischaemia used to study preconditioning in vivo and in vitro leading to some confusion over the effects of preconditioning agents. High concentrations of glutamate or NMDA have been used as models of excitotoxicity in many experimental paradigms. Some molecular changes are associated with preconditioning phenomena, the most prominent being an increased expression of heat shock protein 72 (HSP72). The aims of the current study were to: 1) investigate the effects of exogenous glutamate and other depolarizing agents in the slice preparation and their validity for use as toxic agents 2) examine any potential preconditioning neuroprotection induced by adenosine against various depolarizing agents and elucidate the underlying mechanisms where relevant 3) examine the excitotoxic preconditioning phenomenon and possible underlying mechanisms 4) look at the effectiveness of other known preconditioning agents e.g. ATP-sensitive potassium channel openers against depolarizing agents and identify the underlying mechanisms of protection 5) identify any molecular changes that may occur during acute models of chemical ischemia or acute preconditioning. The rat hippocampal slice preparation was used to investigate the effects of depolarizing agents and preconditioning paradigms upon the extracellularly evoked field epsps, orthodromic and antidromic population spikes. Western blotting was used to detect any changes in the levels of HSP72 in the slices that may have occurred as a result of the depolarizing agents or the preconditioning treatments. It was first established that 5mM and 10mM glutamate induced depressions in the amplitudes of orthodromic population spikes which recovered to a stable plateau. The degree of recovery of the spikes depended partially upon the initial size of the response. As adenosine is known to be released in response to glutamate receptor stimulation, the effects of 5mM glutamate upon the orthodromic spikes were studied in the presence of the A1 receptor antagonist, DPCPX. It was observed that DPCPX did not attenuate the depression of the response during glutamate perfusion but there was a significant elevation in the post-glutamate recovery of the response. This effect was not observed when the protocol was applied to antidromic population spikes and field epsps, both of which showed a depression in response during 5mM glutamate perfusion but recovered fully when glutamate was removed. The field epsps showed a trend whereby smaller epsps recovered to a far greater degree than population spikes. Although this effect was not significant, the NMDA receptor blocker, MK-801, was co-perfused with glutamate during epsp recordings to examine this further. The degree to which MK-801 alone affected the response correlated with the post-glutamate recovery. To study this effect, isolated NMDA-receptor mediated epsps were recorded and the effects of 5mM glutamate upon them were studied. There was a similar tendency for small NMDA-receptor mediated epsps to recover to a higher level following glutamate treatment compared with larger potentials. In the presence of DPCPX, the larger potentials showed a significant elevation in recovery following treatment with glutamate. It was also shown that the post-5mM glutamate recovery of the orthodromic population spikes was elevated by the presence of the A2a receptor antagonist, SCH 58261. Further experiments using the ATP-sensitive potassium channel blocker, glibenclamide, indicated that this effect may be due to increasing the opening of these channels. Adenosine preconditioning was attempted using 10mM glutamate as an insult. It was shown that adenosine could not precondition against this effect in antidromic or orthodromic population spikes. The effects of the sodium-potassium ATPase inhibitor, ouabain, upon the evoked responses were studied as an alternative insult. It was shown that ouabain induced depressions in field epsps, orthodromic and antidromic population spikes. The antidromic population spikes showed significantly smaller depressions than the orthodromic responses. Further experiments using the glutamate receptor antagonist, kynurenic acid, showed that glutamate receptors mediated the effects of ouabain upon the orthodromic population spikes but not the antidromic spikes. Adenosine preconditioning was attempted against ouabain. It was shown that adenosine preconditioned against the effects of ouabain upon orthodromic and antidromic population spikes but not field epsps. Further experiments were conducted using antidromic population spikes. It was shown using various antagonists, that adenosine protection against ouabain was mediated by A1 receptors, ATP-sensitive potassium channels, NMDA receptors and nitric oxide. To extend these results further, preconditioning using the ATP-sensitive potassium channel opener, pinacidil, was attempted against 10mM glutamate and ouabain. It was shown that pinacidil was able to precondition the antidromic population spike against either insult. Using the NMDA receptor antagonist, DL-AP5, showed that the preconditioning effect of pinacidil against ouabain was mediated by NMDA receptors. Another preconditioning paradigm was attempted to see if glutamate could precondition against ouabain. It was shown that pre- treatment with glutamate resulted in enhancing the depressant effect of ouabain upon field epsps and antidromic population spikes. To further examine the effects of ouabain upon antidromic population spikes, ouabain was co-perfused in the presence of the intracellular calcium chelator, BAPTA-AM. This resulted in enhancing the depressant effect of ouabain upon the response. A similar result was observed when the calcium concentration in the perfusion medium was lowered to 0.5mM from 2.5mM whereas increasing the concentration to 5mM attenuated the depressant effect. Ouabain was also co-perfused in the presence of charybdotoxin, a blocker of large-conductance calcium activated potassium channels. It was observed that charybdotoxin enhanced the effect of ouabain upon the antidromic spikes. No changes were detected in HSP72 expression in the slices in response to ouabain treatment, 10mM glutamate treatment, pinacidil preconditioning treatment or glutamate preconditioning. The present results show that glutamate and ouabain can induce depressions in the evoked responses from the rat hippocampal slice and that the effects of 5mM glutamate can be attenuated by adenosine receptor antagonists. In addition, adenosine can precondition against ouabain but not glutamate and this effect involves A1 receptors, NMDA receptors, nitric oxide and ATP-sensitive potassium channels. It has also been observed that pinacidil can precondition against ouabain or glutamate and NMDA receptors may be involved in this effect. The inability of glutamate to precondition against ouabain in evoked responses was also demonstrated. The study highlights the effectiveness of preconditioning agents against different depolarizing agents and the interactions between adenosine and glutamate receptors which play a role in preconditioning

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey - The Hubble Space Telescope Observations, Imaging Data Products and Mosaics

This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at $z\sim1.5-8$, and to study Type Ia SNe beyond $z>1.5$. Five premier multi-wavelength sky regions are selected, each with extensive multiwavelength observations. The primary CANDELS data consist of imaging obtained in the Wide Field Camera 3 / infrared channel (WFC3/IR) and UVIS channel, along with the Advanced Camera for Surveys (ACS). The CANDELS/Deep survey covers \sim125 square arcminutes within GOODS-N and GOODS-S, while the remainder consists of the CANDELS/Wide survey, achieving a total of \sim800 square arcminutes across GOODS and three additional fields (EGS, COSMOS, and UDS). We summarize the observational aspects of the survey as motivated by the scientific goals and present a detailed description of the data reduction procedures and products from the survey. Our data reduction methods utilize the most up to date calibration files and image combination procedures. We have paid special attention to correcting a range of instrumental effects, including CTE degradation for ACS, removal of electronic bias-striping present in ACS data after SM4, and persistence effects and other artifacts in WFC3/IR. For each field, we release mosaics for individual epochs and eventual mosaics containing data from all epochs combined, to facilitate photometric variability studies and the deepest possible photometry. A more detailed overview of the science goals and observational design of the survey are presented in a companion paper.Comment: 39 pages, 25 figure

Health, education, and social care provision after diagnosis of childhood visual disability

Aim: To investigate the health, education, and social care provision for children newly diagnosed with visual disability.Method: This was a national prospective study, the British Childhood Visual Impairment and Blindness Study 2 (BCVIS2), ascertaining new diagnoses of visual impairment or severe visual impairment and blindness (SVIBL), or equivalent vi-sion. Data collection was performed by managing clinicians up to 1-year follow-up, and included health and developmental needs, and health, education, and social care provision.Results: BCVIS2 identified 784 children newly diagnosed with visual impairment/SVIBL (313 with visual impairment, 471 with SVIBL). Most children had associated systemic disorders (559 [71%], 167 [54%] with visual impairment, and 392 [84%] with SVIBL). Care from multidisciplinary teams was provided for 549 children (70%). Two-thirds (515) had not received an Education, Health, and Care Plan (EHCP). Fewer children with visual impairment had seen a specialist teacher (SVIBL 35%, visual impairment 28%, χ2p < 0.001), or had an EHCP (11% vs 7%, χ2p < 0 . 01).Interpretation: Families need additional support from managing clinicians to access recommended complex interventions such as the use of multidisciplinary teams and educational support. This need is pressing, as the population of children with visual impairment/SVIBL is expected to grow in size and complexity.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8--1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the mid-ultraviolet to the near-infrared, and will find and measure Type Ia supernovae at z>1.5 to test their accuracy as standardizable candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10^9 M_\odot to z \approx 2, reaching the knee of the ultraviolet luminosity function (UVLF) of galaxies to z \approx 8. The survey covers approximately 800 arcmin^2 and is divided into two parts. The CANDELS/Deep survey (5\sigma\ point-source limit H=27.7 mag) covers \sim 125 arcmin^2 within GOODS-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (EGS, COSMOS, and UDS) and covers the full area to a 5\sigma\ point-source limit of H \gtrsim 27.0 mag. Together with the Hubble Ultra Deep Fields, the strategy creates a three-tiered "wedding cake" approach that has proven efficient for extragalactic surveys. Data from the survey are nonproprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design. The Hubble data processing and products are described in a companion paper.Comment: Submitted to Astrophysical Journal Supplement Series; Revised version, subsequent to referee repor

Integrated genomic characterization of oesophageal carcinoma

Oesophageal cancers are prominent worldwide; however, there are few targeted therapies and survival rates for these cancers remain dismal. Here we performed a comprehensive molecular analysis of 164 carcinomas of the oesophagus derived from Western and Eastern populations. Beyond known histopathological and epidemiologic distinctions, molecular features differentiated oesophageal squamous cell carcinomas from oesophageal adenocarcinomas. Oesophageal squamous cell carcinomas resembled squamous carcinomas of other organs more than they did oesophageal adenocarcinomas. Our analyses identified three molecular subclasses of oesophageal squamous cell carcinomas, but none showed evidence for an aetiological role of human papillomavirus. Squamous cell carcinomas showed frequent genomic amplifications of CCND1 and SOX2 and/or TP63, whereas ERBB2, VEGFA and GATA4 and GATA6 were more commonly amplified in adenocarcinomas. Oesophageal adenocarcinomas strongly resembled the chromosomally unstable variant of gastric adenocarcinoma, suggesting that these cancers could be considered a single disease entity. However, some molecular features, including DNA hypermethylation, occurred disproportionally in oesophageal adenocarcinomas. These data provide a framework to facilitate more rational categorization of these tumours and a foundation for new therapies