A γ-β frequency transition generated by inter-areal communication in the hippocampus in vitro

Gamma oscillations are generated in area CA3 of the hippocampus both in vitro and in vivo (Fisahn et al., 1998; Csicsvari et al., 2003). Here we present experimental and network simulation data to elucidate the mechanism of the generation of CA3-driven gamma and beta oscillations in area CA1. (1) The frequency of area CA1 output generated by gamma input from area CA3 was dependent on the degree of recruitment of CA1 principal cells. Passive involvement of area CA1 principal cells resulted in a gamma frequency oscillation. Active involvement of CA1 principal cells transformed this gamma oscillation into one at beta frequencies. (2) This beta oscillation in area CA1 was dependent on CA1 recurrent excitation. (3) It was also dependent on the temporal relationship between feedforward excitation of CA1 interneurons (by CA3 output) and feedback excitation of CA1 interneurons (by CA1 output). That is, the network beta oscillation in area CA1 depended on doublet firing of certain interneurons driven by area CA3. (4) The interneuron doublet rate during beta corresponded to whether or not dendrites are oriented horizontally or vertically: Interneurons with vertically oriented dendrites (eg. basket cells and - to a lesser extent - bistratified cells, all receiving input from CA3) fired considerably more doublets than interneurons with horizontally oriented dendrites (horizontal alveus cells or olm cells) which are not contacted by area CA3 and hardly ever fired doublets during beta. Taken together the findings demonstrate that different interneurons can serve different purposes during a given network oscillation, that single interneuron subtypes can mediate multiple network frequencies, and that the frequency of output from a cortical region serves to signal the degree of principal cell recruitment

A γ-β frequency transition generated by inter-areal communication in the hippocampus in vitro

Gamma oscillations are generated in area CA3 of the hippocampus both in vitro and in vivo (Fisahn et al., 1998; Csicsvari et al., 2003). Here we present experimental and network simulation data to elucidate the mechanism of the generation of CA3-driven gamma and beta oscillations in area CA1. (1) The frequency of area CA1 output generated by gamma input from area CA3 was dependent on the degree of recruitment of CA1 principal cells. Passive involvement of area CA1 principal cells resulted in a gamma frequency oscillation. Active involvement of CA1 principal cells transformed this gamma oscillation into one at beta frequencies. (2) This beta oscillation in area CA1 was dependent on CA1 recurrent excitation. (3) It was also dependent on the temporal relationship between feedforward excitation of CA1 interneurons (by CA3 output) and feedback excitation of CA1 interneurons (by CA1 output). That is, the network beta oscillation in area CA1 depended on doublet firing of certain interneurons driven by area CA3. (4) The interneuron doublet rate during beta corresponded to whether or not dendrites are oriented horizontally or vertically: Interneurons with vertically oriented dendrites (eg. basket cells and - to a lesser extent - bistratified cells, all receiving input from CA3) fired considerably more doublets than interneurons with horizontally oriented dendrites (horizontal alveus cells or olm cells) which are not contacted by area CA3 and hardly ever fired doublets during beta. Taken together the findings demonstrate that different interneurons can serve different purposes during a given network oscillation, that single interneuron subtypes can mediate multiple network frequencies, and that the frequency of output from a cortical region serves to signal the degree of principal cell recruitment

GEN1 from a thermophilic fungus is functionally closely similar to non-eukaryotic junction-resolving enzymes

AbstractProcessing of Holliday junctions is essential in recombination. We have identified the gene for the junction-resolving enzyme GEN1 from the thermophilic fungus Chaetomium thermophilum and expressed the N-terminal 487-amino-acid section. The protein is a nuclease that is highly selective for four-way DNA junctions, cleaving 1nt 3′ to the point of strand exchange on two strands symmetrically disposed about a diagonal axis. CtGEN1 binds to DNA junctions as a discrete homodimer with nanomolar affinity. Analysis of the kinetics of cruciform cleavage shows that cleavage of the second strand occurs an order of magnitude faster than the first cleavage so as to generate a productive resolution event. All these properties are closely similar to those described for bacterial, phage and mitochondrial junction-resolving enzymes. CtGEN1 is also similar in properties to the human enzyme but lacks the problems with aggregation that currently prevent detailed analysis of the latter protein. CtGEN1 is thus an excellent enzyme with which to engage in biophysical and structural analysis of eukaryotic GEN1

Whiteness and diasporic Irishness: nation, gender and class

Whiteness is often detached from the notion of diaspora in the recent flurry of interest in the phenomenon, yet it is a key feature of some of the largest and oldest displacements. This paper explores the specific contexts of white racial belonging and status over two centuries in two main destinations of the Irish diaspora, the USA and Britain. Its major contribution is a tracing of the untold story of ‘How the Irish became white in Britain’ to parallel and contrast with the much more fully developed narrative in the USA. It argues that, contrary to popular belief, the racialisation of the Irish in England did not fade away at the end of the nineteenth century but became transmuted in new forms which have continued to place the ‘white’ Irish outside the boundaries of the English nation. These have been strangely ignored by social scientists, who conflate Irishness and working-class identities in England without acknowledging the distinctive contribution of Irish backgrounds to constructions of class difference. Gender locates Irish women and men differently in relation to these class positions, for example allowing mothers to be blamed for the perpetuation of the underclass. Class and gender are also largely unrecognised dimensions of Irish ethnicity in the USA, where the presence of ‘poor white’ neighbourhoods continues to challenge the iconic story of Irish upward mobility. Irishness thus remains central to the construction of mainstream ‘white’ identities in both the USA and Britain into the twenty-first century

Molecular and clinical epidemiology of carbapenem-resistant Enterobacterales in the USA (CRACKLE-2): a prospective cohort study

Background: Carbapenem-resistant Enterobacterales (CRE) are a global threat. We aimed to describe the clinical and molecular characteristics of Centers for Disease Control and Prevention (CDC)-defined CRE in the USA. Methods: CRACKLE-2 is a prospective, multicentre, cohort study. Patients hospitalised in 49 US hospitals, with clinical cultures positive for CDC-defined CRE between April 30, 2016, and Aug 31, 2017, were included. There was no age exclusion. The primary outcome was desirability of outcome ranking (DOOR) at 30 days after index culture. Clinical data and bacteria were collected, and whole genome sequencing was done. This trial is registered with ClinicalTrials.gov, number NCT03646227. Findings: 1040 patients with unique isolates were included, 449 (43%) with infection and 591 (57%) with colonisation. The CDC-defined CRE admission rate was 57 per 100 000 admissions (95% CI 45–71). Three subsets of CDC-defined CRE were identified: carbapenemase-producing Enterobacterales (618 [59%] of 1040), non-carbapenemase-producing Enterobacterales (194 [19%]), and unconfirmed CRE (228 [22%]; initially reported as CRE, but susceptible to carbapenems in two central laboratories). Klebsiella pneumoniae carbapenemase-producing clonal group 258 K pneumoniae was the most common carbapenemase-producing Enterobacterales. In 449 patients with CDC-defined CRE infections, DOOR outcomes were not significantly different in patients with carbapenemase-producing Enterobacterales, non-carbapenemase-producing Enterobacterales, and unconfirmed CRE. At 30 days 107 (24%, 95% CI 20–28) of these patients had died. Interpretation: Among patients with CDC-defined CRE, similar outcomes were observed among three subgroups, including the novel unconfirmed CRE group. CDC-defined CRE represent diverse bacteria, whose spread might not respond to interventions directed to carbapenemase-producing Enterobacterales. Funding: National Institutes of Health

Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved

A novel formulation of inhaled sodium cromoglicate (PA101) in idiopathic pulmonary fibrosis and chronic cough: a randomised, double-blind, proof-of-concept, phase 2 trial

Background Cough can be a debilitating symptom of idiopathic pulmonary fibrosis (IPF) and is difficult to treat. PA101 is a novel formulation of sodium cromoglicate delivered via a high-efficiency eFlow nebuliser that achieves significantly higher drug deposition in the lung compared with the existing formulations. We aimed to test the efficacy and safety of inhaled PA101 in patients with IPF and chronic cough and, to explore the antitussive mechanism of PA101, patients with chronic idiopathic cough (CIC) were also studied. Methods This pilot, proof-of-concept study consisted of a randomised, double-blind, placebo-controlled trial in patients with IPF and chronic cough and a parallel study of similar design in patients with CIC. Participants with IPF and chronic cough recruited from seven centres in the UK and the Netherlands were randomly assigned (1:1, using a computer-generated randomisation schedule) by site staff to receive PA101 (40 mg) or matching placebo three times a day via oral inhalation for 2 weeks, followed by a 2 week washout, and then crossed over to the other arm. Study participants, investigators, study staff, and the sponsor were masked to group assignment until all participants had completed the study. The primary efficacy endpoint was change from baseline in objective daytime cough frequency (from 24 h acoustic recording, Leicester Cough Monitor). The primary efficacy analysis included all participants who received at least one dose of study drug and had at least one post-baseline efficacy measurement. Safety analysis included all those who took at least one dose of study drug. In the second cohort, participants with CIC were randomly assigned in a study across four centres with similar design and endpoints. The study was registered with ClinicalTrials.gov (NCT02412020) and the EU Clinical Trials Register (EudraCT Number 2014-004025-40) and both cohorts are closed to new participants. Findings Between Feb 13, 2015, and Feb 2, 2016, 24 participants with IPF were randomly assigned to treatment groups. 28 participants with CIC were enrolled during the same period and 27 received study treatment. In patients with IPF, PA101 reduced daytime cough frequency by 31·1% at day 14 compared with placebo; daytime cough frequency decreased from a mean 55 (SD 55) coughs per h at baseline to 39 (29) coughs per h at day 14 following treatment with PA101, versus 51 (37) coughs per h at baseline to 52 (40) cough per h following placebo treatment (ratio of least-squares [LS] means 0·67, 95% CI 0·48–0·94, p=0·0241). By contrast, no treatment benefit for PA101 was observed in the CIC cohort; mean reduction of daytime cough frequency at day 14 for PA101 adjusted for placebo was 6·2% (ratio of LS means 1·27, 0·78–2·06, p=0·31). PA101 was well tolerated in both cohorts. The incidence of adverse events was similar between PA101 and placebo treatments, most adverse events were mild in severity, and no severe adverse events or serious adverse events were reported. Interpretation This study suggests that the mechanism of cough in IPF might be disease specific. Inhaled PA101 could be a treatment option for chronic cough in patients with IPF and warrants further investigation