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BackgroundSerosurveys are essential to understand SARS-CoV-2 exposure and enable population-level surveillance, but currently available tests need further in-depth evaluation. We aimed to identify testing-strategies by comparing seven seroassays in a population-based cohort.MethodsWe analysed 6,658 samples consisting of true-positives (n=193), true-negatives (n=1,091), and specimens of unknown status (n=5,374). For primary testing, we used Euroimmun-Anti-SARS-CoV-2-ELISA-IgA/IgG and Roche-Elecsys-Anti-SARS-CoV-2; and virus-neutralisation, GeneScript®cPass™, VIRAMED-SARS-CoV-2-ViraChip®, and Mikrogen-recomLine-SARS-CoV-2-IgG, including common-cold CoVs, for confirmatory testing. Statistical modelling generated optimised assay cut-off-thresholds.FindingsSensitivity of Euroimmun-anti-S1-IgA was 64.8%, specificity 93.3%; for Euroimmun-anti-S1-IgG, sensitivity was 77.2/79.8% (manufacturer’s/optimised cut-offs), specificity 98.0/97.8%; Roche-anti-N sensitivity was 85.5/88.6%, specificity 99.8/99.7%. In true-positives, mean and median titres remained stable for at least 90-120 days after RT-PCR-positivity. Of true-positives with positive RT-PCR (recomLine-RBD) were >94.9% sensitive, >98.1% specific. Seasonality had limited effects; cross-reactivity with common-cold CoVs 229E and NL63 in SARS-CoV-2 true-positives was significant.ConclusionOptimised cut-offs improved test performances of several tests. Non-reactive serology in true-positives was uncommon. For epidemiological purposes, confirmatory testing with virus-neutralisation may be replaced with GeneScript®cPass™ or recomLine-RBD. Head-to-head comparisons given here aim to contribute to the refinement of testing-strategies for individual and public health use.

Introduction The public interest steadily increases in the biological adverse effects caused by components released from resin-based dental restorations. Objective In this study, the cytotoxicity and the genotoxicity were investigated of following released components from dental resin restorations in human gingival fibroblasts (HGF): tetraethyleneglycol dimethacrylate (TEEGDMA), neopentylglycol dimethacrylate (Neopen), diphenyliodoniumchloride (DPIC), triphenyl-stibane (TPSB) and triphenylphosphane (TPP). Methods XTT based cell viability assay was used for cytotoxicity screening of substances. γ-H2AX assay was used for genotoxicity screening. In the γ-H2AX assay, HGFs were exposed to the substances for 6 h. Induced foci represent double DNA strand breaks (DSBs), which can induce ATM-dependent phosphorylation of the histone H2AX. Cell death effects (apoptosis and necrosis), induced by the substances were visually tested by the same investigator using the fluorescent microscope. Results All tested substances induced a dose-dependent loss of viability in HGFs. Following toxicity ranking among the substances at EC50-concentration were found in the XTT assay (mM, mean ± SEM; n = 5): DPIC > Neopen > TPSB > TPP > TEEGDMA. DSB-foci per HGF-cell were obtained, when HGFs were exposed to the EC50-concentration of each substance in the following order (mean ± SEM; n = 3): DPIC > Neopen > TPSB > TPP > TEEGDMA. Multi-foci cells (cells that contain more than 40 foci each) in 80 HGF-cells at EC50-concentration of each substance were found as follow (mean ± SEM; n = 3): DPIC > Neopen > TPP > TPSB > TEEGDMA. Cell apoptosis contained in each substance at EC50-concentration in the following order (mean ± SEM; n = 3): DPIC > Neopen > TPSB > TPP >TEEGDMA. Cell necrosis contained in each substance at EC50-concentration in the following order (mean ± SEM; n = 3): DPIC > Neopen > TPSB > TPP > TEEGDMA. Conclusion Leached components from dental resin restorations can induce DNA DSBs and cell death effects in HGFs.

Given a set of PSA values, we answer the question: “Is its information content typical for the existence of a prostate cancer, or not?” Our findings support PSA screening.