Trends in the numbers of SARS-CoV-2 infections among students: a prospective cohort study comparing students in sports boarding schools with students in day schools during early COVID-19 pandemic

IntroductionDuring the first months of the COVID pandemic it emerged that facilities where people gather or live together in cohorts, such as nursing homes or schools, were particularly at high risk for becoming hotspots of virus transmission. German political and health institutions responded with far-reaching interventions and preventive strategies to protect the population from infection with SARS-CoV-2. In this context, it remains unclear whether boarding schools for sports particularly pose a risk of infection to their residents.MethodsIn a single-center prospective cohort study, numbers of SARS-CoV-2 infections of students in sports boarding schools (n = 11) vs. students attending regular day schools (n = 22) in the region Freiburg/Hochschwarzwald in Germany were investigated over a period from October 2020 to January 2021 via regular virus and antibody screening (German Clinical Trials Register; Study ID: DRKS00021909). In addition, individual and behavioral risk factors for infection were stratified via questionnaire, which provide an indication of cohort specific risk factors for infection and the success of the implementation of hygiene concepts, as well as other infection prevention strategies, within the respective facilities.ResultsRegarding SARS-CoV-2 infection numbers, the screening detected no significant group difference between sports boarding schools vs. day schools.DiscussionThe study results provide indications that sports boarding schools did not pose an increased risk of infection, assuming that the facilities prevent virus transmissions with appropriate preventive strategies and hygiene measures. In future pandemic scenarios larger-scale and multicenter studies are necessary to achieve more comprehensive epidemiological data in this field

Unusual cause of exercise-induced ventricular fibrillation in a well-trained adult endurance athlete: a case report

<p>Abstract</p> <p>Introduction</p> <p>The diseases responsible for sudden deaths in athletes differ considerably with regard to age. In young athletes, congenital malformations of the heart and/or vascular system cause the majority of deaths and can only be detected noninvasively by complex diagnostics. In contrast, in older athletes who die suddenly, atherosclerotic disease of the coronary arteries is mostly found. Reports of congenital coronary anomalies as a cause of sudden death in older athletes are rare.</p> <p>Case presentation</p> <p>A 48-year-old man who was a well-trained, long-distance runner collapsed at the finish of a half marathon because of a myocardial infarction with ventricular fibrillation. Coronary angiography showed an anomalous origin of the right coronary artery from the left sinus of Valsalva with minimal wall alterations. Multislice computed tomography of the coronary arteries confirmed these findings. Cardiomagnetic resonance imaging demonstrated a mild hypokinesia of the basal right- and left-ventricular posterior wall. An electrophysiological study showed an inducible temporary polymorphic ventricular tachycardia and an inducible ventricular fibrillation. The athlete was subsequently treated by acetylsalicylic acid 100 mg (0-1-0), bisoprolol 2.5 mg (1-0-0) and atorvastatin 10 mg (0-0-1) and was instructed to keep his training intensity under the 'individual anaerobic threshold'. Intense and long-lasting exercise under extreme environmental conditions, particularly heat, should also be avoided.</p> <p>Conclusion</p> <p>This case report presents a coronary anomaly as the most likely reason for an exercise-induced myocardial infarction with ventricular fibrillation in a well-trained 48-year-old endurance athlete. Therefore, coronary anomalies have also to be considered as a possible cause of cardiac problems in older athletes.</p

Cultivation of human meniscus cells at different culture conditions

In den letzten Jahren konnte gezeigt werden, dass die Degeneration sowie auch die durch Verletzung bedingten Schäden der Menisci eine große Rolle im Gesundheitswesen spielen. Obwohl viele Studien im Rahmen der Meniskusersatztherapie hoffnungsvolle Ergebnisse bezüglich der Heilungsrate, der klinischen Symptome und eines gewissen Schutzes des Gelenkknorpels propagieren, so bleiben sie doch den Beweis schuldig, dass sie zu einer Wiederherstellung der mechanischen Eigenschaften des Meniskus sowie zu einer Vermeidung der nach totaler Meniskektomie häufig entstehenden Knorpelveränderungen imstande sind. Gerade aufgrund der Tatsache, dass bei den zellfreien Repairsystemen ein inhomogenes Einwachsen der Zellen in die eingenähte Kollagenmatrix beobachtet werden kann und dass die Hauptrisikogruppe der Meniskektomiepatienten mit dieser Therapieform nicht behandelt werden kann, hat uns bewogen, grundlegende Untersuchungen zu einem zellgebundenen Meniskusrepair durchzuführen. In dieser Arbeit konnte gezeigt werden, dass humane Meniskuszellen in vitro kultivierbar sind. Dabei errreichten die Meniskuszellen in der Monolayerkultur die höchste Proliferationsrate bei der Verwendung von HAM'S F 12 Medium mit 20%igem gepooltem Humanserum-Gehalt (maximale Verdopplungsrate/Tag: 0,480), einem Sauerstoff-Gehalt von 16,5% (maximale Verdopplungsrate/Tag: 0,376) sowie einem Kohlendioxid-Gehalt von 5% (maximale Verdopplungsrate/Tag: 0,376) des Begasungsbrutschrankes. Bei den untersuchten 3-dimensionalen Kultursystemen besaß das TissuFleece E® gegenüber dem TissuFoil E® aufgrund des geringeren Kollagenanteiles und der höheren Eigenstabilität die besseren Voraussetzungen für die Verwendung im Rahmen des Tissue Engineering. Dennoch zeigte das Proliferationsverhalten der humanen Meniskuszellen auf den jeweiligen biogenen Trägermaterialien über den kompletten Kulturverlauf von 30 Tagen keinen signifikanten Wachstumsunterschied. Die mittlere Verdopplungsrate/Tag lag auf dem TissuFleece® bei 0,246 und auf dem TissuFoil® bei 0,275. Auf beiden Materialien nahm die Verdopplungsrate/Tag über den Kulturverlauf mit zunehmender Zelldichte ab. Die histologische Auswertung zeigte, dass sich die Meniskuszellen auf beiden Trägermaterialien lediglich auf der Oberfläche angesiedelt haben. Bei der Kultivierung in Alginate beads zeigten die Zellen über den gesamten Kulturverlauf eine relativ konstante Zellzahl. Die gemittelte Verdopplungsrate lag bei 0,125. Wurde zu der 1,2%igen Alginate-Lösung 25 % Synvisc® hinzugegeben, zeigte sich über den Kulturverlauf eine statistisch signifikant niedrigere absolute Zellzahl in den beads (mittlere Verdopplungsrate/Tag: 0,103).In the last years it has been proven that degeneration as well as meniscus-damages caused by injuries play an important role in health care. Even though research on meniscus-substitution-therapy propagates hopeful results with regard to cure rate, clinical symptoms and a certain protection of the articular cartilage, there is still no evidence that by this kind of therapy a rehabilitation of the mechanic properties of the meniscus and a prevention of cartilage-damage, which is often the result of meniscectomy, can be achieved. The very fact that with cellfree repairsystems an inhomogeneous growth of the cells into the sown-in collagenmatrix can be observed and that the major risk group of meniscectomy patients cannot be treated with this kind of therapy gave us the idea to conduct basic research on meniscus-repair based on cells. This dissertation shows that human meniscus cells can be cultivated in vitro. In doing so the meniscus cells in monolayerculture reached the highest proliferationrate using HAM'S F 12 medium with 20% human serum (maximum doubling rate per day: 0,480), an oxygen-concentration of 16,5 % (maximum doubling rate per day: 0,376) as well as a carbondioxid-concentration of 5 % (maximum doubling rate per day: 0,376) of the incubator. Of the 3-dimensional culturesystems analyzed, the TissuFleece E® met the requirements for the use in Tissu Engineering much better than TissuFoil E® because of its lower collagenconcentration and its higher inherent stability. However, the proliferation-behaviour of human meniscus cells on the individual biogen carrier-material didn't show a significant difference in growth in the course of 30 days. The average doubling rate per day was 0,246 on TissuFleece® and 0,275 on TissuFoil®. On both materials the doubling rate per day decreased within these 30 days with increasing cell density. The histological analysis showed that on both materials meniscus cells only settled on the surface. In the cultivation in Alginate beads the number of cells stayed relatively constant in the course of the process. The average doubling rate was 0,125. When 25% Synvisc® was added to the 1,2 percent Alginate-solution, a statistically significant lower absolute number of cells in the beads (average doubling rate per day: 0,103) could be observed in the course of the process