Presynaptic actions of 4-Aminopyridine and γ-aminobutyric acid on rat sympathetic ganglia in vitro

Responses to bath-applications of 4-aminopyridine (4-AP) and -aminobutyric acid (GABA) were recorded intracellularly from neurones in the rat isolated superior cervical ganglion. 4-aminopyridine (0.1–1.0 mmol/l) usually induced spontaneous action potentials and excitatory postsynaptic potentials (EPSPs), which were blocked by hexamethonium. Membrane potential was unchanged; spike duration was slightly increased. Vagus nerve B-and C-fibre potentials were prolonged. In 4-AP solution (0.1–0.3 mmol/l), GABA (0.1 mmol/l), 3-aminopropanesulphonic acid or muscimol evoked bursts of spikes and EPSPs in addition to a neuronal depolarization. These bursts, which were not elicited by glycine, glutamate, taurine or (±)-baclofen, were completely antagonised by hexamethonium, tetrodotoxin or bicuculline methochloride. It is concluded that: (a) 4-AP has a potent presynaptic action on sympathetic ganglia; (b) presynaptic actions of GABA can be recorded postsynaptically in the presence of 4-AP; and (c) the presynaptic GABA-receptors revealed in this condition are similar to those on the postsynaptic membrane

Identifying Biomarkers from Transcriptomic Signatures in Renal Allograft Biopsies Using Deceased and Living Donors.

The survival of transplant kidneys using deceased donors (DD) is inferior to living donors (LD). In this study, we conducted a whole-transcriptome expression analysis of 24 human kidney biopsies paired at 30 minutes and 3 months post-transplantation using DD and LD. The transcriptome profile was found significantly different between two time points regardless of donor types. There were 446 differentially expressed genes (DEGs) between DD and LD at 30 minutes and 146 DEGs at 3 months, with 25 genes common to both time points. These DEGs reflected donor injury and acute immune responses associated with inflammation and cell death as early as at 30 minutes, which could be a precious window of potential intervention. DEGs at 3 months mainly represented the changes of adaptive immunity, immunosuppressive treatment, remodeling or fibrosis via different networks and signaling pathways. The expression levels of 20 highly DEGs involved in kidney diseases and 10 genes dysregulated at 30 minutes were found correlated with renal function and histology at 12 months, suggesting they could be potential biomarkers. These genes were further validated by quantitative polymerase chain reaction (qPCR) in 24 samples analysed by microarray, as well as in a validation cohort of 33 time point unpaired allograft biopsies. This analysis revealed that SERPINA3, SLPI and CBF were up-regulated at 30 minutes in DD compared to LD, while FTCD and TASPN7 were up-regulated at both time points. At 3 months, SERPINA3 was up-regulated in LD, but down-regulated in DD, with increased VCAN and TIMP1, and decreased FOS, in both donors. Taken together, divergent transcriptomic signatures between DD and LD, and changed by the time post-transplantation, might contribute to different allograft survival of two type kidney donors. Some DEGs including FTCD and TASPN7 could be novel biomarkers not only for timely diagnosis, but also for early precise genetic intervention at donor preservation, implantation and post-transplantation, in particular to effectively improve the quality and survival of DD

Xe films on a decagonal Al-Ni-Co quasicrystal surface

The grand canonical Monte Carlo method is employed to study the adsorption of Xe on a quasicrystalline Al-Ni-Co surface. The calculation uses a semiempirical gas-surface interaction, based on conventional combining rules and the usual Lennard-Jones Xe-Xe interaction. The resulting adsorption isotherms and calculated structures are consistent with the results of LEED experimental data. In this paper we focus on five features not discussed earlier (Phys. Rev. Lett. 95, 136104 (2005)): the range of the average density of the adsorbate, the order of the transition, the orientational degeneracy of the ground state, the isosteric heat of adsorption of the system, and the effect of the vertical cell dimension.Comment: 6 pages, 5 pic

Allosteric rescue of catalytically impaired ATP phosphoribosyltransferase variants links protein dynamics to active-site electrostatic preorganisation

Funding: This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) [Grant BB/M010996/1] via EASTBIO Doctoral Training Partnership studentships to B. J. R. and G. F., by Stiftelsen Olle Engkvist Byggmästare [Grant 190-0335] and the Knut and Alice Wallenberg Foundation [Grants 2018.0140 and 2019.0431] to S.C.L.K., and by the European Union’s Horizon 2020 Research and Innovation Programme via a Marie Sklodowska-Curie fellowship [Grant 890562] to M.C. The simulations were enabled by resources provided by the Swedish National Infrastructure for Supercomputing (SNIC, UPPMAX), partially funded by the Swedish Research Council [Grant 2016-07213].ATP phosphoribosyltransferase catalyses the first step of histidine biosynthesis and is controlled via a complex allosteric mechanism where the regulatory protein HisZ enhances catalysis by the catalytic protein HisGS while mediating allosteric inhibition by histidine. Activation by HisZ was proposed to position HisGS Arg56 to stabilise departure of the pyrophosphate leaving group. Here we report active-site mutants of HisGS with impaired reaction chemistry which can be allosterically restored by HisZ despite the HisZ:HisGS interface lying ~20 Å away from the active site. MD simulations indicate HisZ binding constrains the dynamics of HisGS to favour a preorganised active site where both Arg56 and Arg32 are poised to stabilise leaving-group departure in WT-HisGS. In the Arg56Ala-HisGS mutant, HisZ modulates Arg32 dynamics so that it can partially compensate for the absence of Arg56. These results illustrate how remote protein-protein interactions translate into catalytic resilience by restoring damaged electrostatic preorganisation at the active site.Publisher PDFPeer reviewe

Complete Genomic Sequence Of An Avian Pathogenic Escherichia Coli Strain Of Serotype O7:hnt.

Avian pathogenic Escherichia coli (APEC) is associated with colibacillosis in poultry. Here, we present the first complete sequence of an APEC strain of the O7:HNT serotype and ST73 sequence type, isolated from a broiler with cellulitis. Complete genomes of APEC with distinct genetic backgrounds may be useful for comparative analysis.

The interaction between vaginal microbiota, cervical length and vaginal progesterone treatment for preterm birth risk

Background: Preterm birth is the primary cause of infant death worldwide. A short cervix in the second trimester of pregnancy is a risk factor for preterm birth. In specific patient cohorts, vaginal progesterone reduces this risk. Using 16S rRNA gene sequencing we undertook a prospective study in women at risk of preterm birth (n=161) to assess 1) the relationship between vaginal microbiota and cervical length in the second trimester and preterm birth-risk, and 2) the impact of vaginal progesterone on vaginal bacterial communities in women with a short cervix. Results: Lactobacillus iners dominance at 16 weeks gestation was significantly associated with both a short cervix <25mm (n=15, P<0.05), and preterm birth <34+0 weeks (n=18, 38P<0.01; 69% PPV). In contrast, L. crispatus dominance was highly predictive of term birth (n=127, 98% PPV). Cervical shortening and preterm birth were not associated with vaginal dysbiosis. A longitudinal characterization of vaginal microbiota (<18, 22, 28 and 34 weeks) was then undertaken in women receiving vaginal progesterone (400mg/OD, n=25) versus controls (n=42). Progesterone did not alter vaginal bacterial community structure nor reduce L. iners-associated preterm birth (<34 weeks). Conclusions: L. iners dominance of the vaginal microbiota at 16 weeks gestation is a risk factor for preterm birth, whereas L. crispatus dominance is protective against preterm birth. Vaginal progesterone does not appear to impact the pregnancy vaginal microbiota. Patients and clinicians who may be concerned about ‘infection risk’ associated with use of a vaginal pessary during high-risk pregnancy can be reassured

Analogue closed-loop optogenetic modulation of hippocampal pyramidal cells dissociates gamma frequency and amplitude

Gamma-band oscillations are implicated in modulation of attention, integration of sensory information and flexible communication among anatomically connected brain areas. How networks become entrained is incompletely understood. Specifically, it is unclear how the spectral and temporal characteristics of network oscillations can be altered on rapid timescales needed for efficient communication. We use closed-loop optogenetic modulation of principal cell excitability in mouse hippocampal slices to interrogate the dynamical properties of hippocampal oscillations. Gamma frequency and amplitude can be modulated bi-directionally, and dissociated, by phase-advancing or delaying optogenetic feedback to pyramidal cells. Closed-loop modulation alters the synchrony rather than average frequency of action potentials, in principle avoiding disruption of population rate-coding of information. Modulation of phasic excitatory currents in principal neurons is sufficient to manipulate oscillations, suggesting that feed-forward excitation of pyramidal cells has an important role in determining oscillatory dynamics and the ability of networks to couple with one another

Evaluation of EGFR mutation status in cytology specimens: An institutional experience

Epidermal growth factor receptor ( EGFR ) mutation status has been shown to predict response to anti‐EGFR tyrosine kinase inhibitors in non‐small cell lung cancer (NSCLC). In patients with advanced‐stage NSCLC, evaluation of mutational status is increasingly requested on biopsy or fine‐needle aspiration specimens, which often have limited material. There are limited data on the suitability of cytology cell blocks (CB) for EGFR mutation testing. In this study, we report our institutional experience with cytology cell block material for EGFR mutation testing. We retrospectively reviewed EGFR mutation analyses performed on 234 surgical (SP) and cytology (CB) from October 2007 to May 2010. One hundred ninety‐two SP specimens and 42 CB specimens were evaluated for EGFR mutation. CB specimens were evaluated for overall specimen size based on aggregate cellularity in comparison to small biopsy specimens, and percent tumor. Of the 192 SP and 42 CB specimens, 31 (16.1%) and 11 (26.2%) were positive for EGFR mutation, respectively; there does not appear to be an association between mutation detection rate and the source of the specimen ( P = 0.124). Limited DNA was obtained from 70.0% (29/42), including 81.8% (9/11) of those which were mutation positive. Additionally, 45.4% (5/11) of mutation positive specimens had extremely low DNA yields. Although 16.6% (7/42) of CB specimens had 10% tumor. These data indicate that CB specimens provide an alternative source for molecular evaluation of NSCLC, and that tumor percentage may be more important than specimen size and/or DNA yield in determining the suitability of these specimens for testing. Diagn. Cytopathol. 2013;41:316–323. © 2011 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97174/1/21851_ftp.pd

Methodological criteria for the assessment of moderators in systematic reviews of randomised controlled trials : a consensus study

Background: Current methodological guidelines provide advice about the assessment of sub-group analysis within RCTs, but do not specify explicit criteria for assessment. Our objective was to provide researchers with a set of criteria that will facilitate the grading of evidence for moderators, in systematic reviews. Method: We developed a set of criteria from methodological manuscripts (n = 18) using snowballing technique, and electronic database searches. Criteria were reviewed by an international Delphi panel (n = 21), comprising authors who have published methodological papers in this area, and researchers who have been active in the study of sub-group analysis in RCTs. We used the Research ANd Development/University of California Los Angeles appropriateness method to assess consensus on the quantitative data. Free responses were coded for consensus and disagreement. In a subsequent round additional criteria were extracted from the Cochrane Reviewers’ Handbook, and the process was repeated. Results: The recommendations are that meta-analysts report both confirmatory and exploratory findings for subgroups analysis. Confirmatory findings must only come from studies in which a specific theory/evidence based apriori statement is made. Exploratory findings may be used to inform future/subsequent trials. However, for inclusion in the meta-analysis of moderators, the following additional criteria should be applied to each study: Baseline factors should be measured prior to randomisation, measurement of baseline factors should be of adequate reliability and validity, and a specific test of the interaction between baseline factors and interventions must be presented. Conclusions: There is consensus from a group of 21 international experts that methodological criteria to assess moderators within systematic reviews of RCTs is both timely and necessary. The consensus from the experts resulted in five criteria divided into two groups when synthesising evidence: confirmatory findings to support hypotheses about moderators and exploratory findings to inform future research. These recommendations are discussed in reference to previous recommendations for evaluating and reporting moderator studies