Initial Evaluation of a Mobile SARS-CoV-2 RT-LAMP Testing Strategy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) control in the United States remains hampered, in part, by testing limitations. We evaluated a simple, outdoor, mobile, colorimetric reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay workflow where self-collected saliva is tested for SARS-CoV-2 RNA. From July 16, 2020, to November 19, 2020, surveillance samples (n = 4704) were collected from volunteers and tested for SARS-CoV-2 at 5 sites. Twenty-one samples tested positive for SARS-CoV-2 by RT-LAMP; 12 were confirmed positive by subsequent quantitative reverse-transcription polymerase chain reaction (qRT-PCR) testing, whereas 8 tested negative for SARS-CoV-2 RNA, and 1 could not be confirmed because the donor did not consent to further molecular testing. We estimated the false-negative rate of the RT-LAMP assay only from July 16, 2020, to September 17, 2020 by pooling residual heat-inactivated saliva that was unambiguously negative by RT-LAMP into groups of 6 or fewer and testing for SARS-CoV-2 RNA by qRT-PCR. We observed a 98.8% concordance between the RT-LAMP and qRT-PCR assays, with only 5 of 421 RT-LAMP-negative pools (2493 total samples) testing positive in the more-sensitive qRT-PCR assay. Overall, we demonstrate a rapid testing method that can be implemented outside the traditional laboratory setting by individuals with basic molecular biology skills and that can effectively identify asymptomatic individuals who would not typically meet the criteria for symptom-based testing modalities.

Initial evaluation of a mobile SARS-CoV-2 RT-LAMP testing strategy.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) control in the United States remains hampered, in part, by testing limitations. We evaluated a simple, outdoor, mobile, colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay workflow where self-collected saliva is tested for SARS-CoV-2 RNA. From July 16 to November 19, 2020, 4,704 surveillance samples were collected from volunteers and tested for SARS-CoV-2 at 5 sites. A total of 21 samples tested positive for SARS-CoV-2 by RT-LAMP; 12 were confirmed positive by subsequent quantitative reverse-transcription polymerase chain reaction (qRT-PCR) testing, while 8 were negative for SARS-CoV-2 RNA, and 1 could not be confirmed because the donor did not consent to further molecular testing. We estimated the RT-LAMP assay's false-negative rate from July 16 to September 17, 2020 by pooling residual heat-inactivated saliva that was unambiguously negative by RT-LAMP into groups of 6 or less and testing for SARS-CoV-2 RNA by qRT-PCR. We observed a 98.8% concordance between the RT-LAMP and qRT-PCR assays, with only 5 of 421 RT-LAMP negative pools (2,493 samples) testing positive in the more sensitive qRT-PCR assay. Overall, we demonstrate a rapid testing method that can be implemented outside the traditional laboratory setting by individuals with basic molecular biology skills and can effectively identify asymptomatic individuals who would not typically meet the criteria for symptom-based testing modalities.

The disposition and bioavailability of 35S-GSH from 35S-GSSG in BSS PLUS in rabbit ocular tissues.

The purpose of this study was to evaluate the biodistribution and uptake of 35S-GSH into intraocular tissues following the administration of BSS PLUS containing 35S-GSSG by either an anterior chamber or intravitreal injection. This study evaluated the disposition and uptake of the 35S-radiolabel, the intracellular concentrations of 35S-GSH from extracellular 35S-GSSG, and the percentage of 35S-GSH to the total cellular GSH pool. Glutathione was analyzed by high-performance liquid chromatography (HPLC) using fluorescence detection after derivitizing the thiols in situ with monobromobimane. The effluent from the GSH peak was then collected for measurement of 35S-GSH. After an anterior chamber injection of 35S-BSS PLUS, 35S-radioactivity rapidly disappeared from the aqueous humor between 0.5 and 2 hours; corneal 35S-radioactivity remained constant over time. 35S-GSH was detected in the iris and ciliary body. However, in the cornea, 35S-GSH became the predominant radioactive thiol in the stroma, endothelium, and epithelium; the corneal stroma appeared to be a possible GSH reservoir for the adjacent corneal layers. After an intravitreal injection, 35S-radioactivity slowly decreased in the vitreous humor but was readily taken up by the tissues of the posterior segment, especially the retina and choroid, which showed the greatest concentrations of 35S-GSH of all tissues studied. The data from this study demonstrate that 35S-GSSG in BSS PLUS is metabolized and taken up by ocular cells and that 35S-GSH becomes incorporated into the intracellular GSH pool of ocular tissues.