Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members

Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic. Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine. Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis. Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years

Les sous-types de récepteurs de transmission de l'angiotensine II: caractérisation, distribution et mécanisme de transmission du signal

Doctorat en sciences médicalesinfo:eu-repo/semantics/nonPublishe

Inactivation of β-adrenergic receptors by N-ethylmalmeimide: Permissive role of β-adrenergic agents in relation to adenylate cyclase activation

The β1-adrenergic receptors of turkey erythrocyte membranes have been identified by the specific binding of the radiolabeled antagonist (-)-[3H]dihydroalprenolol. Binding of β-adrenergic agonists to these receptors sites sensitizes them to inactivation by the alkylating agent N-ethylmaleimide. A dose- and time-dependent decrease of 45 to 60% of the sites is commonly observed. Binding of (-)-3H-dihydroalprenolol and β-adrenergic agonists to the remaining sites occurs with the same characteristics as for the untreated receptor population. Kinetic experiments reveal that the rate of inactivation is proportional to the concentration of N-ethylmaleimide (between 5.5 and 450μM). In contrast, the rate of inactivation reaches a plateau value when increasing the concentration of the agonist. The rate of inactivation is half-maximal in presence of 1.3 μM (-)-epinephrine or 20μM (+)-epinephrine. This marked stereospecificity, along with the close identity of the above concentrations with the equilibrium dissociation constant (K(D)) of the epinephrine isomers for binding to the β-receptor (i.e. 2.0 μM for (-)-epinephrine and 21 μM for (+)-epinephrine) indicate that N-ethylmaleimide inactivates the agonist-bound form of the receptor. The second-order rate constant (k2) of the inactivation process, in the presence of 15 β-adrenergic ligands, was found to correlate with their capability to stimulate the adenylate cyclase activity, i.e. 'intrinsic activity'. Since all tested ligands were able to cause a complete and dose-dependent displacement of bound (-)-[3H]dihydroalprenolol, it is likely that both the intrinsic activity and k2 of each adrenergic ligand reflect an inherent property of the ligand-bound receptor. The proportionality between k2 and the intrinsic acid activity further suggests that β-adrenergic agonists 'induce' or 'favor' a conformational change of the receptor, resulting in adenylate cyclase activation and the uncovering of an alkylable group which becomes exposed to N-ethylmaleimide in the active conformation.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Gonadal steroid control of α-adrenergic and muscarinic acetylcholine receptors in human myometrium

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Identification and characterization of α1-adrenergic receptors in human myometrium by [3H]prazosin binding

α1-adrenergic receptors can be directly characterized in myometrial membranes using the specific α1-adrenergic radioligand [3H]prazosin. Compared to the previous approach, this allows a more precise determination of the α1-adrenergic receptor number and of their agonist and antagonist binding properties. Use of this radioligand might prove to be a powerful tool in distinguishing α1-receptors from the total amount of α-adrenergic receptors. As a practical application, it becomes now possible to determine whether the reported influence of sex steroid hormones on the total α-adrenergic receptor population in animal uteri does also apply to the α1-subpopulation.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Identification and characterization of α2-adrenergic receptors in human myometrium by [3H]rauwolscine binding

Human myometrium contains α3-adrenergic receptors which can be identified by binding of the α2-adrenergic antagonist [3H]rauwolscine. Scatchard analysis of saturation binding data on myometrial membranes revealed that [3H]rauwolscine bound to a single class on noncooperative sites (262 ± 89 fmol/mg of membrane protein) with high affinity (i.e. with an equilibrium dissociation constant of 5.3 ± 2.2 nM). The α2-adrenergic nature of these sites was derived from the order of potencies and stereospecificity of α-adrenergic agonists and antagonists to compete with [3H]rauwolscine binding.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Differential regulation of α-adrenergic receptor subclasses by gonadal steroids in human myometrium

Adrenergic receptors have been shown to be involved in uterine contractility. α-Adrenergic receptors cause uterine contraction, whereas β-adrenergic receptors induce relaxation. In animals, myometrial α-adrenergic receptors are regulated by gonadal steroids. We have identified α1- and α2-adrenergic receptors in myometrial membranes using the newly developed radiolabeled specific antagonists [3H]prazosin and [3H]rauwolscine. This allowed characterization of both receptor subclasses individually and study of them in various physiological and pharmacological conditions in the human, i.e. during different phases of the menstrual cycle, in postmenopausal women, term pregnancy, and during depo-progestin (medroxyprogesterone acetate) therapy. The affinity and number of α1-adrenergic receptors were unchanged in all conditions, whereas the number of α2-adrenergic receptors increased concomitantly with circulating plasma estradiol levels. However, this latter effect was counteracted by progesterone. These results are an example of the heteroregulation of membrane receptors by estrogens and progesterone and throw new light on the regulatory mechanisms involved in uterine contractility in the human.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Evidence for essential disulfide bonds in β1-adrenergic receptors of turkey erythrocyte membranes. Inactivation by dithiothreitol

The radiolabeled β-adrenergic antagonists (-)-[3H]-dihydroalprenolol binds to a single class of noncooperative sites on turkey erythrocyte membranes. These sites have previously been identified as the functional β-adrenergic receptors. Treatment of the membranes with the reducing agent dithiothreitol causes a decrease in the number of binding sites, without affecting the affinity of (-)-[3H]dihydroalprenolol for the remaining sites. The binding activity is partially restored by extensive washing of the dithiothreitol-treated membranes. No restoration occurs when the wash buffer contains 2 mM N-ethylmaleimide or 10 mM reduced glutathione. The effect of dithiohreitol is mimicked by a hundredfold higher concentration of the monosulfydryl derivatives: reduced glutathione, cysteine, and mercaptoethanol. In contrast, treatment of the membranes with the metal chelators ethylenediamine tetraacetate and ethylene glycol bis(β-amino-ethyl ether)N,N'-tetraacetic acid (10 mM) does not affect (-)-[3H]dihydroalprenolol binding. Kinetic data indicate that dithiothreitol inactivates the β-receptors according to a bimolecular reaction mechanism, with a second order rate constant (k2) of approximately 1.27 M-1 x S-1 at 30°C. The data suggest that dithiothreitol inactivates the β-receptors by reducing one or more disulfide bonds. Both β-adrenergic agonists and antagonists cause an effective protection of the (-)-[3H]dihydroalprenolol binding sites against inactivation by dithiothreitol. The protection is dose-dependent, and linearly related to the fraction of receptor sites occupied by the tracer. The protection is stereospecific for both agonists (epinephrine) and antagonists (propranolol) and reflects, for the same concentration of agonists, the order of affinities for the receptor. The α-adrenergic agents clonidine (agonist) and phentolamine (antagonist), and the nonbioactive compound pyrocatechol do not confer an appreciable protection at concentrations as high as 100 μM. Receptor protection by β-adrenergic agonists and antagonists proceed by causing a conformational change of the receptors as to bury the disulfide bonds or by shielding bonds located near or at the binding site of the receptor.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Conformational changes of β-adrenergic and muscarinic receptors in the presence of agonist molecules

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe