Pulseless electrical activity in in-hospital cardiac arrest - A crossroad for decisions

Background PEA is often seen during resuscitation, either as the presenting clinical state in cardiac arrest or as a secondary rhythm following transient return of spontaneous circulation (ROSC), ventricular fibrillation/tachycardia (VF/VT), or asystole (ASY). The aim of this study was to explore and quantify the evolution from primary/secondary PEA to ROSC in adults during in-hospital cardiac arrest (IHCA). Methods We analyzed 700 IHCA episodes at one Norwegian hospital and three U.S. hospitals at different time periods between 2002 and 2021. During resuscitation ECG, chest compressions, and ventilations were recorded by defibrillators. Each event was manually annotated using a graphical application. We quantified the transition intensities, i.e., the propensity to change from PEA to another clinical state using time-to-event statistical methods. Results Most patients experienced PEA at least once before achieving ROSC or being declared dead. Time average transition intensities to ROSC from primary PEA (n = 230) and secondary PEA after ASY (n = 72) were 0.1 per min, peaking at 4 and 7 minutes, respectively; thus, a patient in these types of PEA showed a 10% chance of achieving ROSC in one minute. Much higher transition intensities to ROSC, average of 0.15 per min, were observed for secondary PEA after VF/VT (n = 83) or after ROSC (n = 134). Discussion PEA is a crossroad in which the subsequent course is determined. The four distinct presentations of PEA behave differently on important characteristics. A transition to PEA during resuscitation should encourage the resuscitation team to continue resuscitative efforts.This work was partially supported by the Spanish Ministerio de Ciencia, Innovacion y Universidades through grant RTI2018-101475-BI00, jointly with the Fondo Europeo de Desarrollo Regional (FEDER), and by the Basque Government through grant IT1229-19. This study has been made possible by DAM foundation and the Norwegian Health Association

Heart rate and QRS duration as biomarkers predict the immediate outcome from pulseless electrical activity

Introduction Pulseless electrical activity (PEA) is commonly observed in in-hospital cardiac arrest (IHCA). Universally available ECG characteristics such as QRS duration (QRSd) and heart rate (HR) may develop differently in patients who obtain ROSC or not. The aim of this study was to assess prospectively how QRSd and HR as biomarkers predict the immediate outcome of patients with PEA. Method We investigated 327 episodes of IHCA in 298 patients at two US and one Norwegian hospital. We assessed the ECG in 559 segments of PEA nested within episodes, measuring QRSd and HR during pauses of compressions, and noted the clinical state that immediately followed PEA. We investigated the development of HR, QRSd, and transitions to ROSC or no-ROSC (VF/VT, asystole or death) in a joint longitudinal and competing risks statistical model. Results Higher HR, and a rising HR, reflect a higher transition intensity (“hazard”) to ROSC (p < 0.001), but HR was not associated with the transition intensity to no-ROSC. A lower QRSd and a shrinking QRSd reflect an increased transition intensity to ROSC (p = 0.023) and a reduced transition intensity to no-ROSC (p = 0.002). Conclusion HR and QRSd convey information of the immediate outcome during resuscitation from PEA. These universally available and promising biomarkers may guide the emergency team in tailoring individual treatment.publishedVersio

Characteristics of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) rRNA genes of Apis mellifera (Insecta: Hymenoptera): structure, organization, and retrotransposable elements

As an accompanying manuscript to the release of the honey bee genome, we report the entire sequence of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) ribosomal RNA (rRNA)-encoding gene sequences (rDNA) and related internally and externally transcribed spacer regions of Apis mellifera (Insecta: Hymenoptera: Apocrita). Additionally, we predict secondary structures for the mature rRNA molecules based on comparative sequence analyses with other arthropod taxa and reference to recently published crystal structures of the ribosome. In general, the structures of honey bee rRNAs are in agreement with previously predicted rRNA models from other arthropods in core regions of the rRNA, with little additional expansion in non-conserved regions. Our multiple sequence alignments are made available on several public databases and provide a preliminary establishment of a global structural model of all rRNAs from the insects. Additionally, we provide conserved stretches of sequences flanking the rDNA cistrons that comprise the externally transcribed spacer regions (ETS) and part of the intergenic spacer region (IGS), including several repetitive motifs. Finally, we report the occurrence of retrotransposition in the nuclear large subunit rDNA, as R2 elements are present in the usual insertion points found in other arthropods. Interestingly, functional R1 elements usually present in the genomes of insects were not detected in the honey bee rRNA genes. The reverse transcriptase products of the R2 elements are deduced from their putative open reading frames and structurally aligned with those from another hymenopteran insect, the jewel wasp Nasonia (Pteromalidae). Stretches of conserved amino acids shared between Apis and Nasonia are illustrated and serve as potential sites for primer design, as target amplicons within these R2 elements may serve as novel phylogenetic markers for Hymenoptera. Given the impending completion of the sequencing of the Nasonia genome, we expect our report eventually to shed light on the evolution of the hymenopteran genome within higher insects, particularly regarding the relative maintenance of conserved rDNA genes, related variable spacer regions and retrotransposable elements

Key roles for AMP-activated protein kinase in the function of the carotid body?

The carotid bodies play a critical role in initiating compensatory ventilatory responses to hypoxia. However, the complete mechanism by which hypoxia excites the oxygen-sensing carotid body type 1 cells has not been fully defined. We have previously proposed that the enzyme adenosine monophosphateactivated protein kinase (AMPK) may couple hypoxic inhibition of mitochondrial oxidative phosphorylation to carotid body type I cell excitation (Evans, Mustard, Wyatt, Peers, Dipp, Kumar, Kinnear and Hardie 2005). Here we discuss evidence that AMPK is a key requirement for hypoxic chemotransduction by the carotid body. In addition, we postulate upon a role for AMPK in the plasticity observed in the carotid body during both chronic and chronic intermittent hypoxia

Phylogeographic information systems: putting the geography into phylogeography

Phylogeography is concerned with the observation, description and analysis of the spatial distribution of genotypes and the inference of historical scenarios. In the past, the discipline has concentrated on the historical 'phylo-' component through the utilization of phylogenetic analyses. In contrast, the spatial '-geographic' component is not a prominent feature of many existing phylogenetic approaches and has often been dealt with in a relatively naive fashion. Recently, there has been a resurgence of interest in the importance of geography in evolutionary biology. Thus, we believe that it is time to assess how geographic information is currently handled and incorporated into phylogeographical analysis. Geographical information systems (GISs) are computer systems that facilitate the integration and interrelation of different geographically referenced data sets; however, so far they have been little utilized by the phylogeographical community to manage, analyse and disseminate phylogeographical data. However, the growth in individual studies and the resurgence of interest in the geographical components of genetic pattern and biodiversity should stimulate further uptake. Some advantages of GIS are the integration of disparate data sets via georeferencing, dynamic data base design and update, visualization tools and data mining. An important step in linking GIS to existing phylogeographical and historical biogeographical analysis software and the dissemination of spatial phylogenies will be the establishment of 'GeoPhylo' data standards. We hope that this paper will further stimulate the resurgence of geography as an equal partner in the symbiosis that is phylogeography as well as advertise some benefits that can be obtained from the application of GIS practices and technologies.</p

Genomics of tolerance to abiotic stress in the Triticeae

Genomics platforms offer unprecedented opportunities to identify, select and in some cases clone the genes and the quantitative trait loci (QTLs) that govern the tolerance of Triticeae to abiotic stresses and, consequently, grain yield. Transcriptome profiling and the other \u201comics\u201d platforms provide further information to unravel gene functions and validate the role of candidate genes. This review provides a synopsis of the main results on the studies that have investigated the genomics of Triticeae crops under conditions of abiotic constraints. With their rich biodiversity and high functional plasticity in response to environmental stresses, Triticeae crops provide an ideal ground for taking full advantage of the opportunities offered by genomics approaches. Ultimately, the practical impact of the knowledge and materials generated through genomics-based approaches will depend on their integration and exploitation within the extant breeding programs