Proposed Framework for Considering SARS-CoV-2 Antigen Testing of Unexposed Asymptomatic Workers in Selected Workplaces.

OBJECTIVES: To propose a framework for considering SARS-CoV-2 antigen testing of unexposed asymptomatic workers in selected workplaces. METHODS: This is a commentary based on established occupational safety and health principles, published articles, and other pertinent literature, including non-peer-reviewed preprints in medrixiv.org prior to April 16, 2021. RESULTS: Not applicable to this commentary/viewpoint article. CONCLUSION: Antigen testing is a rapidly evolving and useful public health tool that can be used to guide measures to reduce spread of SARS-CoV-2 in the community and in selected workplaces. This commentary provides a proposed framework for occupational safety and health practitioners and employers for considering antigen testing as a method to screen asymptomatic workers in selected non-healthcare settings. When applied selectively, antigen testing can be a useful, effective part of a comprehensive workplace program for COVID-19 prevention and control.

Considerations for Pooled Testing of Employees for SARS-CoV-2.

OBJECTIVES: To identify important background information on pooled tested of employees that employers workers, and health authorities should consider. METHODS: This paper is a commentary based on the review by the authors of pertinent literature generally from preprints in medrixiv.org prior to August 2020. RESULTS/CONCLUSIONS: Pooled testing may be particularly useful to employers in communities with low prevalence of COVID-19. It can be used to reduce the number of tests and associated financial costs. For effective and efficient pooled testing employers should consider it as part of a broader, more comprehensive workplace COVID-19 prevention and control program. Pooled testing of asymptomatic employees can prevent transmission of SARS-CoV-2 and help assure employers and customers that employees are not infectious.

Examination of genetic variants involved in generation and biodisposition of kinins in patients with angioedema.

BACKGROUND: Angioedema (AE) is idiopathic in the majority of cases. We studied patients with AE for genetic variants of proteins involved with bradykinin generation and biodisposition. METHODS: One hundred sixty one patients with AE were recruited at a university hospital clinic. Patients were categorized according to the proposed pathogenesis of AE: low C1 inhibitor (C1-INH) and C4 levels, autoimmune disease, cancer, angiotensin-converting enzyme (ACE) inhibitor-induced, nonsteroidal antiinflammatory drug (NSAID)-induced, or idiopathic. In addition, each patient had a blood sample analyzed for a complement profile and enzymes (C1-INH and C4). Fifty-two of the patients were tested for genetic variants in factor XII, plasminogen-activator inhibitor-1 (PAI-1), ACE, and aminopeptidase P (APP). RESULTS: The cause of angioedema was identified in 59/161 (37%) of the cases: 3 (2%) patients had a low plasma C1-INH and C4; 20 (12%) were ACE inhibitor-induced; 12 (7%) were associated with autoimmune disorders; 7 (4%) were associated with malignancy; and 17 (11%) were associated with NSAIDs. In the remaining 102 (63%) patients the cause of angioedema was idiopathic. Of 52 patients with genetic analysis, 13 (25%) had a genetic variant in APP, 10 (19%) in ACE, 13 (25%) in PAI-1, and 0 in Factor XII. CONCLUSIONS: In addition to related diseases and medications causing AE, certain genetic variants encoding proteins involved in bradykinin generation and/or catabolism pathways may be involved in the pathogenesis of AE.

Evaluation of irritancy and sensitization potential of metalworking fluid mixtures and components.

There are approximately 1.2 million workers exposed to metalworking fluids (MWF), which are used to reduce the heat and friction associated with industrial machining and grinding operations. Irritancy and sensitization potential of 9 National Toxicology Program (NTP) nominated MWFs (TRIM 229, TRIM VX, TRIM SC210, CIMTECH 310, CIMPERIAL 1070, CIMSTAR 3800, SYNTILO 1023, SUPEREDGE 6768, and CLEAREDGE 6584) were examined in a combined local lymph node assay (LLNA). BALB/c mice were dermally exposed to each MWF at concentrations up to 50%. Significant irritation was observed after dermal exposure to all MWFs except CIMTECH 310 and SYNTILO 1023. Of the 9 MWFs, 6 induced greater than a 3-fold increase in lymphocyte proliferation and 7 tested positive in the irritancy assay. TRIM VX yielded the lowest EC3 value (6.9%) with respect to lymphocyte proliferation. Chemical components of TRIM VX identified using HPLC were screened for sensitization potential using structural activity relationship (SAR) modeling and the LLNA. TOPKAT predicted triethanolamine (TEA) as a sensitizer while Derek for Windows predicted only 4-chloro-3-methylphenol (CMP) to be positive for sensitization. When tested in the LLNA only CMP (EC3 = 11.6%) and oleic acid (OA) (EC3 = 29.7%) were identified as sensitizers. Exposure to all tested TRIM VX components resulted in statistically significant irritation. An additive proliferative response was observed when mixtures of the two identified sensitizing TRIM VX components, OA and CMP, were tested in the LLNA. This is one explanation of why the EC3 value of TRIM VX, with respect to lymphocyte proliferation, is lower than those assigned to its sensitizing components.

Physical-chemical and solvent considerations in evaluating the influence of carbon chain length on the skin sensitization activity of 1-bromoalkanes.

The murine local lymph node assay (LLNA) is an internationally accepted assay for identification of contact allergens. The LLNA has also been used in research studies to evaluate contact allergen potency, as well as chemical structural-allergenic activity relationships. The 1-bromoalkanes have been used in such a manner as they represent a chemical series with generally the same chemical reactivity but differing in alkane carbon chain length-dependent lipid solubilities. Previous reports noted a biphasic LLNA response with increasing carbon chain length that peaked at the 16-carbon chain (C16) of 1-bromohexadecane (delivered in an acetone-olive oil [AOO] vehicle; 4:1). In the present study, this biphasic LLNA response was confirmed, and 1-bromoalkane chemical-physical factors were explored using both modeling tools and further laboratory studies to help understand this finding. Volatility and effect of vehicle on 1-bromoalkanes' sensitizations were assessed. Selected 1-bromoalkanes were tested in the LLNA using the polar, protic vehicle, tetrahydrofuran-butanol (THF-BuOH; 1:1), to compare to the nonpolar (aprotic) vehicle AOO 1-bromoalkanes-LLNA responses. Enhanced 1-bromoalkane LLNA responses were observed using the THF-BuOH vehicle but with the greatest activity still observed for 1-bromohexadecane (C16). The shorter 1-bromoalkanes were subject to volatile losses upon application with approximately 75% volatile loss from a surface of 1-bromohexane (C6) within 5 min at room temperature. It is concluded that multiple factors, in addition to lipid solubility, including vehicle, solvation, and retention on the skin surface contribute to the apparent potency of 1-bromoalkanes in the LLNA.

Bioaerosol sampling for the detection of aerosolized influenza virus.

BACKGROUND: Influenza virus was used to characterize the efficacy of a cyclone-based, two-stage personal bioaerosol sampler for the collection and size fractionation of aerosolized viral particles. METHODS: A Collison single-jet nebulizer was used to aerosolize the attenuated FluMist vaccine into a calm-air settling chamber. Viral particles were captured with bioaerosol samplers that utilize 2 microcentrifuge tubes to collect airborne particulates. The first tube (T1) collects particles greater than 1.8 microm in diameter, while the second tube (T2) collects particles between 1.0 and 1.8 microm, and the back-up filter (F) collects submicron particles. Following aerosolization, quantitative PCR was used to detect and quantify H1N1 and H3N2 influenza strains. RESULTS: Based on qPCR results, we demonstrate that aerosolized viral particles were efficiently collected and separated according to aerodynamic size using the two-stage bioaerosol sampler. Most viral particles were collected in T2 (1-1.8 microm) and on the back-up filter (< 1 microm) of the bioaerosol sampler. Furthermore, we found that the detection of viral particles with the two-stage sampler was directly proportional to the collection time. Consequently, viral particle counts were significantly greater at 40 minutes in comparison to 5, 10 and 20 minute aerosol collection points. CONCLUSIONS: Due to a lack of empirical data, aerosol transmission of influenza is often questioned. Using FluMist, we demonstrated that a newly developed bioaerosol sampler is able to recover and size fractionate aerosolized viral particles. This sampler should be an important tool for studying viral transmission in clinical settings and may significantly contribute towards understanding the modes of influenza virus transmission.