Background The extent to which children and adolescents contribute to SARS-CoV-2 transmission remains not fully understood. Novel high-capacity testing methods may provide real-time epidemiological data in educational settings helping to establish a rational approach to prevent and minimize SARS-CoV-2 transmission. We investigated whether pooling of samples for SARS-CoV-2 detection by RT-qPCR is a sensitive and feasible high-capacity diagnostic strategy for surveillance of SARS-CoV-2 infections in schools. Methods In this study, students and school staff of 14 educational facilities in Germany were tested sequentially between November 9 and December 23, 2020, two or three times per week for at least three consecutive weeks. Participants were randomized for evaluation of two different age adjusted swab sampling methods (oropharyngeal swabs or buccal swabs compared to saliva swabs using a ‘lolli method’). Swabs were collected and pooled for SARS-CoV-2 RT-qPCR. Individuals of positive pooled tests were retested by RT-qPCR the same or the following day. Positive individuals were quarantined while the SARS-CoV-2 negative individuals remained in class with continued pooled RT-qPCR surveillance. The study is registered with the German Clinical Trials register (registration number: DRKS00023911). Findings 5,537 individuals were eligible and 3970 participants were enroled and included in the analysis. In students, a total of 21,978 swabs were taken and combined in 2218 pooled RT-qPCR tests. We detected 41 positive pooled tests (1·8%) leading to 36 SARS-CoV-2 cases among students which could be identified by individual re-testing. The cumulative 3-week incidence for primary schools was 564/100,000 (6/1064, additionally 1 infection detected in week 4) and 1249/100,000 (29/2322) for secondary schools. In secondary schools, there was no difference in the number of SARS-CoV-2 positive students identified from pooled oropharyngeal swabs compared to those identified from pooled saliva samples (lolli method) (14 vs. 15 cases; 1·3% vs. 1·3%; OR 1.1; 95%-CI 0·5–2·5). A single secondary school accounted for 17 of 36 cases (47%) indicating a high burden of asymptomatic prevalent SARS-CoV-2 cases in the respective school and community. Interpretation In educational settings, SARS-CoV-2 screening by RT-qPCR-based pooled testing with easily obtainable saliva samples is a feasible method to detect incident cases and observe transmission dynamics. Funding Federal Ministry of education and research (BMBF; Project B-FAST in “NaFoUniMedCovid19”; registration number: 01KX2021).

Background:The endothelium requires stabilization factors for efficient blood vessel formation. Results: Engulfment and cell motility 1/dedicator of cytokinesis 180 (Elmo1/Dock180) expression reduces endothelial cell apoptosis in vitro and in vivo. Conclusion: Elmo1/Dock180 protects endothelial cells from apoptosis and acts as a stabilization factor for the endothelium. Significance: First report revealing a cell-intrinsic, pro-survival function of Elmo1/Dock180 in the endothelium.

1 Prostaglandin E2 (PGE2) is an autacoid that decreases proteoglycan synthesis, increases metalloprotease production by cultured chondrocytes, and can modulate some of the actions of interleukin-l on cartilage. The objective of the present study was to characterize the subtype of prostaglandin E2 receptor present in bovine chondrocytes in culture. 2 Primary cultures of articular chondrocytes were prepared from slices of bovine carpal cartilage by sequential digestion with type III hyaluronidase, trypsin, type II collagenase, followed by overnight incubation in Dulbecco's Modified Eagle's Medium (DMEM) with type II collagenase, washing, and seeding at a density of 2 x 105 cells cm-2 in DMEM with 10% foetal bovine serum.3 PGE2 and carbaprostacyclin induced dose-dependent increases in intracellular cyclic AMP in bovine chondrocytes in culture. The potencies of these compounds were different, and maximal doses of PGE2 and carbaprostacyclin had an additive effect. PGD2 induced a small increase in intracellular cyclic AMP only at a high concentration (10-' M).4 PGE2 was more potent that the EP2 agonist 11-deoxy-PGE, at inducing increases in intracellular cyclic AMP. The EP2 agonist butaprost, however, induced only a small increase at a concentration of l0-5 M. 17-Phenyl-PGE2 (EPI agonist), sulprostone and MB 28767 (15S-hydroxy-9-oxo-16-phenoxy-wotetranorprost-13E-enoic acid) (EP3 agonists) did not induce an increase in intracellular cyclic AMP at concentrations up to l0-' M. The EP4 antagonist AH 23848B ([1a(Z),2fl,5a]-(±)-7-[5-[[(l,1'-biphenyl)-4-yl]methoxy]-2-(4-morpholinyl)-3-oxocyclopentyl]-5-heptenoic acid) antagonized PGE2 but not carbaprostacyclin effects on intracellular cyclic AMP. The Schild plot slope was different from 1 but this could be due to an interaction of PGE2 with IP receptors in high doses. The exact nature of the antagonism by compound AH 23848B could not be definitely established in these experimental conditions. 6 Neither PGE2 nor any of its analogues inhibited the increase in intracellular cyclic AMP induced by forskolin, and pertussis toxin did not alter the response to PGE2, suggesting that no Gi-coupled PGE2 receptors are present in these cells. Stimulation with PGE2 did not induce significant increases in intracellular inositol-trisphosphate levels nor increases in intracellular free calcium as determined by confocal microscopy, suggesting the absence of phospholipase-C-coupled or of calcium channel-coupled PGE2 receptors in bovine chondrocytes in these experimental conditions. 7 These results show for the first time that bovine chondrocytes in culture present a functional PGE2 receptor that has some pharmacological characteristics of an EP4 subtype, as well as an IP receptor.