T84 Monolayer Cell Cultures Support Productive HBoV and HSV-1 Replication and Enable In Vitro Co-Infection Studies.

Based on several clinical observations it was hypothesized that herpesviruses may influence the replication of human bocaviruses, the second known parvoviruses that have been confirmed as human pathogens. While several cell lines support the growth of HSV-1, HBoV-1 was exclusively cultivated on air-liquid interface cultures, the latter being a rather complicated, slow, and low throughput system. One of the cell lines are T84 cells, which are derived from the lung metastasis of a colorectal tumor. In this study, we provide evidence that T84 also supports HBoV replication when cultivated as monolayers, while simultaneously being permissive for HSV-1. The cell culture model thus would enable co-infection studies of both viruses and is worth being optimized for high throughput studies with HBoV-1. Additionally, the study provides evidence for a supporting effect of HSV-1 on the replication and packaging of HBoV-1 progeny DNA into DNase-resistant viral particles.

Direct comparison of Altona-SARS-CoV-2 dual target RT-qPCR Assay with commercial LAMP Assay using throat washes in health care staff testing.

Background: Rapid molecular diagnostics by PCR has a crucial role in handling the global SARS-CoV-2 pandemic. As diagnoses are time-sensitive and global supply chains are susceptible to various factors alternative detection methods would be an important backup. Objectives: During the study the performance of a commercially available isothermal LAMP method for SARS-CoV-2 detection was compared to a IVD RT-PCR Assays using throat wash specimens that were routinely taken in our hospital setting. Study design: Throat wash specimens of hospital staff (n = 174) previously tested positive for SARS-CoV-2 by the Altona Diagnostics RealStar SARS-CoV-2 RT-PCR (Altona Diagnostics, Hamburg, Germany) was tested for SARS-CoV-2 also by the SARS-CoV-2 Rapid Colorimetric LAMP Assay (NEB Germany GmbH, Frankfurt a.M., Germany). Results: The sensitivity of the colorimetric LAMP Assay compared to RT-qPCR was 78.74%, and the specificity was determined to 88.24% with a positive predictive value of 0.986 and a negative predicitve value of 0.882. The positive and negative likelihood ratio for LAMP was 6.693 and 0.241, respectively, while the diagnostic odds ratio was 27.77. Conclusions: In times of limited PCR test ressources and in settings with limited PCR capacities, the colorimetric LAMP Assay could serve as an alternative, if a calculable loss of sensitivity is acceptable from the Public Health perspective in certain settings.

A JAM-A-tetraspanin-αvß5 integrin complex regulates contact inhibition of locomotion.

Contact inhibition of locomotion (CIL) is a process that regulates cell motility upon collision with other cells. Improper regulation of CIL has been implicated in cancer cell dissemination. Here, we identify the cell adhesion molecule JAM-A as a central regulator of CIL in tumor cells. JAM-A is part of a multimolecular signaling complex in which tetraspanins CD9 and CD81 link JAM-A to αvß5 integrin. JAM-A binds Csk and inhibits the activity of αvß5 integrin-associated Src. Loss of JAM-A results in increased activities of downstream effectors of Src, including Erk1/2, Abi1, and paxillin, as well as increased activity of Rac1 at cell-cell contact sites. As a consequence, JAM-A-depleted cells show increased motility, have a higher cell-matrix turnover, and fail to halt migration when colliding with other cells. We also find that proper regulation of CIL depends on αvß5 integrin engagement. Our findings identify a molecular mechanism that regulates CIL in tumor cells and have implications on tumor cell dissemination.

Limits and Opportunities of SARS-CoV-2 Antigen Rapid Tests: An Experienced-Based Perspective.

BACKGROUND: Due to the steadily rising case numbers of SARS-CoV-2 infections worldwide, there is an increasing need for reliable rapid diagnostic devices in addition to existing gold standard PCR methods. Actually, public attention is focused on antigen assays including lateral flow tests (LFTs) as a diagnostic alternative. Therefore, different LFTs were analyzed regarding their performance in a clinical setting. MATERIAL AND METHODS: A pilot sample panel of 13 bronchoalveolar fluids (BALFs) and 60 throat washing (TW) samples with confirmed PCR results, as well as eight throat washes invalid by PCR, were tested with the BIOCREDIT test (RapiGEN), the PanbioTM assay (Abbott), and the SARS-CoV-2 rapid antigen test (Roche). CONCLUSION: The analyzed antigen test showed an interassay correlation of 27.4%, with overall specificities ranging from 19.4% to 87.1%, while sensitivities of the respective tests ranged between 33.3% and 88.1%. Because these assays did not entirely meet all high expectations, their benefit has to be carefully evaluated for the respective test strategy and setting.

Differences in biocompatibility of microneedles from cyclic olefin polymers with human endothelial and epithelial skin cells.

Microneedles are promising devices for transdermal delivery and diagnostic applications, due to their minimally invasive and painless nature of application. However, so far, applications are limited to small scale research projects. Material selection and production for larger projects remain a challenge. In vitro testing using human cell culture could bridge the gap between cost effective screening of suitable materials and concerns for safety and ethics. In this study, materials were tested for effects on viability and morphology of human endothelial cells and keratinocytes. In addition, materials were assessed for their potential to influence cellular differentiation and barrier formation. Elution-based testing of inflammatory markers revealed no negative effects in all applied tests, whereas the assessment of differentiation markers on cells in direct contact with the material showed differences and allowed the selection of candidate materials for future medical device applications. This study illustrates that elution-based biocompatibility testing can paint an incomplete picture. Advanced staining techniques and cell types specific for the application of the medical device improve material selection to reduce and replace animal testing at an early stage in the development process. © 2018 The Authors. journal Of Biomedical Materials Research Part A Published By Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 505-512, 2019.