Openings of the Rat Recombinant α1 Homomeric Glycine Receptor as a Function of the Number of Agonist Molecules Bound

The functional properties of rat homomeric α1 glycine receptors were investigated using whole-cell and outside-out recording from human embryonic kidney cells transfected with rat α1 subunit cDNA. Whole-cell dose-response curves gave EC50 estimates between 30 and 120 μM and a Hill slope of ∼3.3. Single channel recordings were obtained by steady-state application of glycine (0.3, 1, or 10 μM) to outside-out patches. Single channel conductances were mostly 60–90 pS, but smaller conductances of ∼40 pS were also seen (10% of the events) with a relative frequency that did not depend on agonist concentration. The time constants of the apparent open time distributions did not vary with agonist concentration, but short events were more frequent at low glycine concentrations. There was also evidence of a previously missed short-lived open state that was more common at lower glycine concentrations. The time constants for the different components of the burst length distributions were found to have similar values at different concentrations. Nevertheless, the mean burst length increased with increasing glycine. This was because the relative area of each burst-length component was concentration dependent and short bursts were favored at lower glycine concentrations. Durations of adjacent open and shut times were found to be strongly (negatively) correlated. Additionally, long bursts were made up of longer than average openings separated by short gaps, whereas short bursts usually consisted of single isolated short openings. The most plausible explanation for these findings is that long bursts are generated when a higher proportion of the five potential agonist binding sites on the receptor is occupied by glycine. On the basis of the concentration dependence and the intraburst structure we provide a preliminary kinetic scheme for the activation of the homomeric glycine receptor, in which any number of glycine molecules from one to five can open the channel, although not with equal efficiency

Understanding Patterns of Emergency Department (ED) Use over time in Ontario to plan new EDs for the future

Introduction The Applied Health Research Question (AHRQ) portfolio is an initiative funded by the Ontario Ministry of Health and Long-Term Care, leveraging the linked data and scientific expertise at ICES to answer questions that directly impact healthcare policy, planning or practice. Objectives and Approach The objective of this project was to evaluate historical patterns of emergency department (ED) use to better plan for a new emergency Department in Kingston and to better understand the factors contributing to increasing ED utilization. Emergency departments across Ontario continue to see consistent increases in volume at rates exceeding expected volume growth due to population growth alone. Some hospitals across the province observe significantly higher volume increases compared to the provincial average. Results From 2006/07 to 2016/17, rate and volume of emergency department visits in Ontario increased 8.82% and 19.87% respectively. Throughout the same period, emergency department visit rate and volume at Kingston General Hospital increased 20.70%, and 27.2%. Using historical data and projected population growth by age and sex, we were able to estimate that emergency department volume would increase at least 11.94% by 2025 due to estimated shifts in population size and distribution (by age and sex) alone. From 2006/07 to 2016/17, the greatest rate of increase in reason for ED visits was mental/behavioral problems. Throughout this period the increase in volume and rate of ED visits due to mental/behavioural problems was 274.46% and 259.59% respectively. Conclusion/Implications Population-specific volume projections and historical trends in ED use can be utilized for planning ED operations to improve efficiency and patient care quality. This has been used to inform the redesign of the ED at the Kingston Health Sciences Centre to ensure it will meet the needs of the community

Human α3β4 Neuronal Nicotinic Receptors Show Different Stoichiometry if They Are Expressed in Xenopus Oocytes or Mammalian HEK293 Cells

The neuronal nicotinic receptors that mediate excitatory transmission in autonomic ganglia are thought to be formed mainly by the α3 and β4 subunits. Expressing this composition in oocytes fails to reproduce the properties of ganglionic receptors, which may also incorporate the α5 and/or β2 subunits. We compared the properties of human α3β4 neuronal nicotinic receptors expressed in Human embryonic kidney cells (HEK293) and in Xenopus oocytes, to examine the effect of the expression system and α:β subunit ratio.Two distinct channel forms were observed: these are likely to correspond to different stoichiometries of the receptor, with two or three copies of the α subunit, as reported for α4β2 channels. This interpretation is supported by the pattern of change in acetylcholine (ACh) sensitivity observed when a hydrophilic Leu to Thr mutation was inserted in position 9' of the second transmembrane domain, as the effect of mutating the more abundant subunit is greater. Unlike α4β2 channels, for α3β4 receptors the putative two-α form is the predominant one in oocytes (at 1:1 α:β cRNA ratio). This two-α form has a slightly higher ACh sensitivity (about 3-fold in oocytes), and displays potentiation by zinc. The putative three-α form is the predominant one in HEK cells transfected with a 1:1 α:β DNA ratio or in oocytes at 9:1 α:β RNA ratio, and is more sensitive to dimethylphenylpiperazinium (DMPP) than to ACh. In outside-out single-channel recordings, the putative two-α form opened to distinctive long bursts (100 ms or more) with low conductance (26 pS), whereas the three-α form gave rise to short bursts (14 ms) of high conductance (39 pS).Like other neuronal nicotinic receptors, the α3β4 receptor can exist in two different stoichiometries, depending on whether it is expressed in oocytes or in mammalian cell lines and on the ratio of subunits transfected

Investigation of non-structural carbohydrates and xylem anatomy in petiole of grapevine varieties during water limitation and after re-irrigation

Water shortage (WS) during growing of Vitis vinifera L. can limit shoot growth and affect yield and fruit quality, as well as allocation of carbon reserves into perennial organs for the upcoming years. Varietal anatomical differences, such as specific mean xylem vessel diameter in petiole, are expected to influence water transport in canes facing water limitation. Several authors have also evidenced that non-structural carbohydrates (NSC) of adjacent living parenchyma are involved in the repair mechanism of embolized vessels. In this work, we evaluated NSC level and xylem anatomy in petiole of Cabernet Sauvignon and Syrah varieties, subjected to WS and subsequent water refilling in the summer of 2017. The anatomical analysis highlighted that Syrah had high frequency of classes of large vessels, and that the xylem differentiation of vascular bundles was also affected by WS. Moreover, petiole NSC content was significantly influenced by WS and recovery, supporting the hypothesis that starch mobilization was associated to an elevated concentration in soluble NSC. This effect was determinant for Cabernet Sauvignon, whose stress response seemed to be based mainly on NSC metabolism. Finally, Syrah, differently to Cabernet Sauvignon, sustained the WS-induced increase in soluble NSC of petiole also 18 h after re-watering

Analysis of Non-Structural Carbohydrates and Xylem Anatomy of Leaf Petioles Offers New Insights in the Drought Response of Two Grapevine Cultivars

In grapevine, the anatomy of xylem conduits and the non-structural carbohydrates (NSCs) content of the associated living parenchyma are expected to influence water transport under water limitation. In fact, both NSC and xylem features play a role in plant recovery from drought stress. We evaluated these traits in petioles of Cabernet Sauvignon (CS) and Syrah (SY) cultivars during water stress (WS) and recovery. In CS, the stress response was associated to NSC consumption, supporting the hypothesis that starch mobilization is related to an increased supply of maltose and sucrose, putatively involved in drought stress responses at the xylem level. In contrast, in SY, the WS-induced increase in the latter soluble NSCs was maintained even 2 days after re-watering, suggesting a different pattern of utilization of NSC resources. Interestingly, the anatomical analysis revealed that conduits are constitutively wider in SY in well-watered (WW) plants, and that water stress led to the production of narrower conduits only in this cultivar

Starting, building and sustaining a program of research in emergency medicine in Canada

Objective: To develop pragmatic recommendations for starting, building and sustaining a program of research in emergency medicine (EM) in Canada at sites with limited infrastructure and/or prior research experience. Methods: At the direction of the Canadian Association of Emergency Physicians (CAEP) academic section, we assembled an expert panel of 10 EM researchers with experience building programs of research. Using a modified Delphi approach, our panel developed initial recommendations for (1) starting, (2) building, and (3) sustaining a program of research in EM. These recommendations were peer-reviewed by emergency physicians and researchers from each of the panelist’s home institutions and tested for face and construct validity, as well as ease of comprehension. The recommendations were then iteratively revised based on feedback and suggestions from peer review and amended again after being presented at the 2020 CAEP academic symposium. Results: Our panel created 15 pragmatic recommendations for those intending to start (formal research training, find mentors, local support, develop a niche, start small), build (funding, build a team, collaborate, publish, expect failure) and sustain (become a mentor, obtain leadership roles, lead national studies, gain influence, prioritize wellness) a program of EM research in centers without an established research culture. Additionally, we suggest four recommendations for department leads aiming to foster a program of research within their departments. Conclusion: These recommendations serve as guidance for centres wanting to establish a program of research in EM

Multiplying the serum aminotransferase by the acetaminophen concentration to predict toxicity following overdose The APAP × AT multiplication product

Context. The first available predictors of hepatic injury following acetaminophen (APAP) overdose are the serum APAP and aminotransferases [AT, i.e., aspartate (AST) aminotransferase or alanine (ALT) aminotransferase]. Objective. We describe the initial value, rate of change, and interrelationship between these biomarkers in patients who develop hepatotoxicity despite treatment following acute overdose. A new parameter, the APAP × AT multiplication product, is proposed for early risk stratification. Methods. We conducted a descriptive study of individuals selected from a multicenter retrospective cohort of patients hospitalized for APAP poisoning. We selected those acute APAP overdose patients who subsequently developed AT >1,000 IU/L. Rising serum AT values were compared to simultaneously measured (or estimated) falling serum APAP. The APAP × AT was expressed relative to initiation of acetylcysteine therapy and grouped by time to meeting hepatotoxicity criteria. Results. In the 94 cases studied, serum APAP concentrations were still appreciable Because serum AT rose rapidly (doubling time 9.5 h ) and APAP fell slowly (half-life 4.8 h), the multiplication product remained elevated during the first 12-24 h of antidotal therapy, especially among patients who developed earlier hepatotoxicity (AT > 1,000 IU/L). Discussion and conclusions. The APAP × AT multiplication product, calculated at the time of presentation and after several h of antidotal therapy, holds promise as a new risk predictor following APAP overdose. It requires neither graphical interpretation nor accurate time of ingestion, two limitations to current risk stratification

High risk clinical characteristics for subarachnoid haemorrhage in patients with acute headache: prospective cohort study

Objective To identify high risk clinical characteristics for subarachnoid haemorrhage in neurologically intact patients with headache

Acute Management and Outcomes of Patients with Diabetes Mellitus Presenting to Canadian Emergency Departments with Hypoglycemia

Objectifs: Cette vérification rétrospective des dossiers a permis d\u27examiner les données démographiques, les examens, la prise en charge et les résultats des patients adultes souffrant de diabète sucré qui se sont présentés aux services des urgences (SU) au Canada. Méthodes: Tous les sites ont mené une recherche dans leurs dossiers médicaux électroniques à l\u27aide des codes de la Classification internationale des maladies, dixième révision, pour relever les visites aux SU entre 2008 et 2010 qui étaient liées à l\u27hypoglycémie. Les caractéristiques des patients, les données démographiques, la prise en charge aux SU, les ressources des SU et les résultats sont rapportés. Résultats: Un total de 1039 patients de plus de 17 ans ont été inclus dans l\u27étude; 347 (33,4 %) ont été classifiés comme étant des cas de diabète de type 1 et 692 (66,6 %) ont été classifiés comme étant des cas de diabète de type 2. Les patients souffrant du diabète de type 2 étaient beaucoup plus âgés (73 ans vs 49 ans; p\u3c0,0001) et avaient plus d\u27affections chroniques inscrites à leur dossier (tous p\u3c0,001). La plupart des sujets arrivaient par ambulance, et 39 % des cas montraient des scores de triage qui révélaient des tableaux cliniques graves. Les traitements contre l\u27hypoglycémie étaient fréquents (75,7 %) durant le transport préhospitalier; 38,5 % recevaient du glucose et 40,1 % recevaient du glucagon par voie intraveineuse. Les traitements administrés dans les SU contre l\u27hypoglycémie comprenaient le glucose par voie orale (76,8 %), le glucose par voie intraveineuse (29,6 %) et en perfusion continue (27,7 %). Les examens diagnostiques (81,9 %) comprenaient fréquemment les électrocardiogrammes (51,9 %), la radiographie thoracique (37,5 %) et la tomodensitométrie crânienne (14,5 %). La plupart des patients (73,5 %) recevaient leur congé. Cependant, plus de sujets souffrant du diabète de type 2 nécessitaient une admission (30,3 vs 8,8 %). Les instructions de congé étaient étayées chez seulement 55,5 % des patients, et l\u27orientation vers des services de diabète se rencontrait chez moins de 20 % des cas. Une variation considérable dans la prise en charge de l\u27hypoglycémie existait entre les SU. Conclusions: Les patients souffrant de diabète qui se présentaient à un SU en raison d\u27une hypoglycémie consomment considérablement de ressources en soins de santé, puis une variation est observée dans la pratique. Les SU devraient élaborer des protocoles de prise en charge de l\u27hypoglycémie en portant une attention à la planification du congé pour réduire la récurrence

Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study

Objective To measure the sensitivity of modern third generation computed tomography in emergency patients being evaluated for possible subarachnoid haemorrhage, especially when carried out within six hours of headache onset