Sudden cardiac death in marathons: a systematic review

The aim of this systematic review is to summarise the results of cohort studies that examined the incidence of SCD in marathons and to assess the quality of the methods used. A search of the PROSPERO international database revealed no prospective or published systematic reviews investigating SCD in marathons. The review was conducted using studies that reported and characterised the incidence of SCD in people participating in marathons. Studies were identified via electronic database searches (Medline, CINAHL, SPORTDiscus and Google Scholar) from January 1, 1966 to October 1, 2014 and through manual literature searches. 7 studies met the inclusion criteria and were included in this review. 6 of the studies were conducted in the USA and 1 in the UK. These studies covered a 34-year period involving between 215,413 and 3,949,000 runners. The SCD of between 4 and 28 people are recorded in the papers and the reported estimates of the incidence of SCD in marathons ranged widely from 0.6 to 1.9 per 100,000 runners. The proportion of those suffering SCD who were male ranged from 57.1% to 100% and the mean age reported in the papers, ranged from 37 to 48. This review raises 4 methodological concerns over i) collating reports of SCD in marathons; ii) time of death in relation to the marathon; iii) the use of registrants rather than runners in the estimates of sample size and iv) limited detail on runners exercise history. These four concerns all threaten the reliability and interpretation of any estimate of SCD incidence rates in marathons. This review recommends that the methods used to collect data on SCD in marathons be improved and that a central reporting system be established

Successful treatment of a patient with COVID-19-induced severe ARDS, pneumothorax, and pneumomediastinum with awake vv-ECMO implantation

Management of acute respiratory distress syndrome (ARDS) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still a challenge for the staff on intensive-care units (ICU's) around the world. Many of these patients are treated with invasive ventilation. Sometimes, the occurrence of pneumothorax and/or pneumomediastinum can complicate the course of the disease because initiation of invasive ventilation might be fatal in those patients. Venovenous extracorporal membrane oxygenation (vv-ECMO) is increasingly used to prevent patients with severe ARDS from hypoxia. However, clear recommendations for or against the initiation of vv-ECMO in awake patients are currently lacking. We present the case of a 42-year-old patient with COVID-19-associated severe ARDS, pneumothorax, and pneumomediastinum. To preserve sufficient oxygenation and to avoid invasive ventilation, we implanted a vv-ECMO while the patient was awake. The patient recovered and was discharged home 41 days after transfer to our hospital. We therefore suggest that awake implantation of vv-ECMO might be useful in a subgroup of patients with severe ARDS caused by SARS-CoV-2. However, further evidence is needed to verify our hypothesis

Efficiency of primary saliva secretion: an analysis of parameter dependence in dynamic single-cell and acinus models, with application to aquaporin knockout studies

Secretion from the salivary glands is driven by osmosis following the establishment of osmotic gradients between the lumen, the cell and the interstitium by active ion transport. We consider a dynamic model of osmotically driven primary saliva secretion and use singular perturbation approaches and scaling assumptions to reduce the model. Our analysis shows that isosmotic secretion is the most efficient secretion regime and that this holds for single isolated cells and for multiple cells assembled into an acinus. For typical parameter variations, we rule out any significant synergistic effect on total water secretion of an acinar arrangement of cells about a single shared lumen. Conditions for the attainment of isosmotic secretion are considered, and we derive an expression for how the concentration gradient between the interstitium and the lumen scales with water- and chloride-transport parameters. Aquaporin knockout studies are interpreted in the context of our analysis and further investigated using simulations of transport efficiency with different membrane water permeabilities. We conclude that recent claims that aquaporin knockout studies can be interpreted as evidence against a simple osmotic mechanism are not supported by our work. Many of the results that we obtain are independent of specific transporter details, and our analysis can be easily extended to apply to models that use other proposed ionic mechanisms of saliva secretion

What do aquaporin knockout studies tell us about fluid transport in epithelia?

The investigation of near-isosmotic water transport in epithelia goes back over 100 years; however, debates over mechanism and pathway remain. Aquaporin (AQP) knockouts have been used by various research groups to test the hypothesis of an osmotic mechanism as well as to explore the paracellular versus transcellular pathway debate. Nonproportional reductions in the water permeability of a water-transporting epithelial cell (e.g., a reduction of around 80–90 %) compared to the reduction in overall water transport rate in the knockout animal (e.g., a reduction of 50–60 %) are commonly found. This nonproportionality has led to controversy over whether AQP knockout studies support or contradict the osmotic mechanism. Arguments raised for and against an interpretation supporting the osmotic mechanism typically have partially specified, implicit, or incorrect assumptions. We present a simple mathematical model of the osmotic mechanism with clear assumptions and, for models based on this mechanism, establish a baseline prediction of AQP knockout studies. We allow for deviations from isotonic/isosmotic conditions and utilize dimensional analysis to reduce the number of parameters that must be considered independently. This enables a single prediction curve to be used for multiple epithelial systems. We find that a simple, transcellular-only osmotic mechanism sufficiently predicts the results of knockout studies and find criticisms of this mechanism to be overstated. We note, however, that AQP knockout studies do not give sufficient information to definitively rule out an additional paracellular pathway

First report from the German COVID-19 autopsy registry

BACKGROUND: Autopsies are an important tool in medicine, dissecting disease pathophysiology and causes of death. In COVID-19, autopsies revealed e.g., the effects on pulmonary (micro)vasculature or the nervous system, systemic viral spread, or the interplay with the immune system. To facilitate multicentre autopsy-based studies and provide a central hub supporting autopsy centres, researchers, and data analyses and reporting, in April 2020 the German COVID-19 Autopsy Registry (DeRegCOVID) was launched. METHODS: The electronic registry uses a web-based electronic case report form. Participation is voluntary and biomaterial remains at the respective site (decentralized biobanking). As of October 2021, the registry included N=1129 autopsy cases, with 69271 single data points including information on 18674 available biospecimens gathered from 29 German sites. FINDINGS: In the N=1095 eligible records, the male-to-female ratio was 1·8:1, with peaks at 65-69 and 80-84 years in males and >85 years in females. The analysis of the chain of events directly leading to death revealed COVID-19 as the underlying cause of death in 86% of the autopsy cases, whereas in 14% COVID-19 was a concomitant disease. The most common immediate cause of death was diffuse alveolar damage, followed by multi-organ failure. The registry supports several scientific projects, public outreach and provides reports to the federal health authorities, leading to legislative adaptation of the German Infection Protection Act, facilitating the performance of autopsies during pandemics. INTERPRETATION: A national autopsy registry can provide multicentre quantitative information on COVID-19 deaths on a national level, supporting medical research, political decision-making and public discussion. FUNDING: German Federal Ministries of Education and Research and Health. Hintergrund: Obduktionen sind ein wichtiges Instrument in der Medizin, um die Pathophysiologie von Krankheiten und Todesursachen zu untersuchen. Im Rahmen von COVID-19 wurden durch Obduktionen z.B. die Auswirkungen auf die pulmonale Mikrovaskulatur, das Nervensystem, die systemische Virusausbreitung, und das Zusammenspiel mit dem Immunsystem untersucht. Um multizentrische, auf Obduktionen basierende Studien zu erleichtern und eine zentrale Anlaufstelle zu schaffen, die Obduktionszentren, Forscher sowie Datenanalysen und -berichte unterstützt, wurde im April 2020 das deutsche COVID-19-Autopsieregister (DeRegCOVID) ins Leben gerufen. Methoden: Das elektronische Register verwendet ein webbasiertes elektronisches Fallberichtsformular. Die Teilnahme ist freiwillig und das Biomaterial verbleibt am jeweiligen Standort (dezentrales Biobanking). Im Oktober 2021 umfasste das Register N=1129 Obduktionsfälle mit 69271 einzelnen Datenpunkten, die Informationen über 18674 verfügbare Bioproben enthielten, die von 29 deutschen Standorten gesammelt wurden. Ergebnisse: In den N=1095 ausgewerteten Datensätzen betrug das Verhältnis von Männern zu Frauen 1,8:1 mit Spitzenwerten bei 65-69 und 80-84 Jahren bei Männern und >85 Jahren bei Frauen. Die Analyse der Sequenz der unmittelbar zum Tod führenden Ereignisse ergab, dass in 86 % der Obduktionsfälle COVID-19 die zugrunde liegende Todesursache war, während in 14 % der Fälle COVID-19 eine Begleiterkrankung war. Die häufigste unmittelbare Todesursache war der diffuse Alveolarschaden, gefolgt von Multiorganversagen. Das Register unterstützt mehrere wissenschaftliche Projekte, die Öffentlichkeitsarbeit und liefert Berichte an die Bundesgesundheitsbehörden, was zu einer Anpassung des deutschen Infektionsschutzgesetzes führte und die Durchführung von Obduktionen in Pandemien erleichtert. Interpretation: Ein nationales Obduktionsregister kann multizentrische quantitative Informationen über COVID-19-Todesfälle auf nationaler Ebene liefern und damit die medizinische Forschung, die politische Entscheidungsfindung und die öffentliche Diskussion unterstützen. Finanzierung: Bundesministerien für Bildung und Forschung und für Gesundheit

The use of Lapita pottery : results from the first analysis of lipid residues

Biomolecular and isotopic characterisation of absorbed organic residues have been performed on eight dentate-stamped and two plain Lapita potsherds from the site of Teouma, in Vanuatu. Lipid profiles associated with decorated pots are homogenous, suggesting that similar food types or mixtures of food types were placed in these vessels. This suggests a high degree of consistency in the use of Lapita decorated pots, irrespective of the morphological and stylistic variation of these vessels. Data obtained from single-compound isotope analysis are also not consistent with marine resources as potential food sources for Lapita vessels. The absence of such commonly consumed, ubiquitous and easily accessible resources in Lapita vessels suggests that these pots were not manufactured to be used for ordinary occasions and day-to-day food consumption. This is the first time tangible data related to the use of these vessels are provided to support this claim in addition to contextual inferences

Antiplasmodial and trypanocidal activity of violacein and deoxyviolacein produced from synthetic operons.

BACKGROUND: Violacein is a deep violet compound that is produced by a number of bacterial species. It is synthesized from tryptophan by a pathway that involves the sequential action of 5 different enzymes (encoded by genes vioA to vioE). Violacein has antibacterial, antiparasitic, and antiviral activities, and also has the potential of inducing apoptosis in certain cancer cells. RESULTS: Here, we describe the construction of a series of plasmids harboring the complete or partial violacein biosynthesis operon and their use to enable production of violacein and deoxyviolacein in E.coli. We performed in vitro assays to determine the biological activity of these compounds against Plasmodium, Trypanosoma, and mammalian cells. We found that, while deoxyviolacein has a lower activity against parasites than violacein, its toxicity to mammalian cells is insignificant compared to that of violacein. CONCLUSIONS: We constructed E. coli strains capable of producing biologically active violacein and related compounds, and propose that deoxyviolacein might be a useful starting compound for the development of antiparasite drugs

Fatal cases after Omicron BA.1 and BA.2 infection: Diffuse alveolar damage occurs only in a minority - results of an autopsy study: [Preprint]

Compared with previously prevalent variants of SARS-CoV-2, the Omicron lineages BA.1 and BA.2 are known to be associated with mild clinical courses. In addition, well-established animal models do not develop severe diseases. To address whether the supposedly fatal cases after Omicron-BA.1/2 infection show the known COVID-19 organ alterations, especially in the lungs, 23 full and 3 partial autopsies in the deceased with known Omicron BA.1/2 infections have been consecutively performed. Viral RNA was determined by RT-qPCR and RNA-in situ hybridization. The lineages were analyzed by whole genome sequencing or S-gene analysis. Despite high viral loads in almost all nasopharyngeal swabs and in 13 lung tissue samples, death caused by COVID-19-associated diffuse alveolar damage (DAD) in the acute and organizing stages was found in only eight cases (31%). This rate is significantly lower compared to previous studies, including non-Omicron variants, where rates of 92% and 69% for non-vaccinated and fully vaccinated vaccines were observed. It is of special interest that neither vaccination status nor known risk factors (i.e., age, comorbidities, obesity, immuno-suppression) were significantly associated with a direct cause of death by COVID-19. Only the reason for the hospital admission of the patients due to COVID-19-related symptoms showed a significant correlation with directly COVID-19-caused deaths (P < 0.001). DAD still occurred in the Omicron BA.1/BA.2 era of the SARS-CoV-2 pandemic but at a considerably lower frequency than seen with previous variants of concern. In our study, none of the known risk factors discriminated the cases with COVID-19-caused death from those that had COVID-19 infections but died due to a different disease. Therefore, the host's genomics might play a key role in this regard. Further studies are urgently needed to elucidate the existence of a genomic mechanism as a risk factor for a fatal course

Fatal cases after Omicron BA.1 and BA.2 infection: results of an autopsy study

Objectives Omicron lineages BA.1/2 are considered to cause mild clinical courses. Nevertheless, fatal cases after those infections are recognized but little is known about risk factors. Methods Twenty-three full and three partial autopsies in deceased with known Omicron BA.1/2 infections have been consecutively performed. The investigations included histology, blood analyses and molecular virus detection. Results COVID-19-associated diffuse alveolar damage (DAD) was found in only eight cases (31%). This rate is significantly lower compared to previous studies, including non-Omicron variants, where rates between 69% and 92% were observed. Neither vaccination nor known risk factors were significantly associated with a direct cause of death by COVID-19. Only those patients who were admitted to the clinic due to COVID-19 but not for other reasons had a significant association with a direct COVID-19 caused death (P > 0.001).). Conclusions DAD still occurred in the Omicron BA.1/BA.2 era but at considerably lower frequency than seen with previous variants of concern. None of the known risk factors discriminated the cases with COVID-19-caused death from those that died due to a different disease. Therefore, the host's genomics might play a key role in this regard. Further studies should elucidate the existence of such a genomic risk factor