Development of a protein assay with copper chelator chromeazurol B, based on the biuret reaction

AbstractThe COVID-19 pandemic continues to have an unprecedented impact on societies and economies worldwide. There remains an ongoing need for high-performance SARS-CoV-2 tests which may be broadly deployed for infection monitoring. Here we report a highly sensitive single molecule array (Simoa) immunoassay in development for detection of SARS-CoV-2 nucleocapsid protein (N-protein) in venous and capillary blood and saliva. In all matrices in the studies conducted to date we observe >98% negative percent agreement and >90% positive percent agreement with molecular testing for days 1–7 in symptomatic, asymptomatic, and pre-symptomatic PCR+ individuals. N-protein load decreases as anti-SARS-CoV-2 spike-IgG increases, and N-protein levels correlate with RT-PCR Ct-values in saliva, and between matched saliva and capillary blood samples. This Simoa SARS-CoV-2 N-protein assay effectively detects SARS-CoV-2 infection via measurement of antigen levels in blood or saliva, using non-invasive, swab-independent collection methods, offering potential for at home and point of care sample collection.

Download Full-text

Impact of routine S100B protein assay on CT scan use in children with mild traumatic brain injury

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2020-1293 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Fleur Lorton ◽

Jeanne Simon-Pimmel ◽

Damien Masson ◽

Elise Launay ◽

Christèle Gras-Le Guen ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

Mild Traumatic Brain Injury ◽

University Hospital ◽

S100b Protein ◽

Research Network ◽

Ct Scans ◽

Intermediate Risk ◽

Protein Assay ◽

The Impact

AbstractObjectivesTo evaluate the impact of implementing a modified Pediatric Emergency Care Applied Research Network (PECARN) rule including the S100B protein assay for managing mild traumatic brain injury (mTBI) in children.MethodsA before-and-after study was conducted in a paediatric emergency department of a French University Hospital from 2013 to 2015. We retrospectively included all consecutive children aged 4 months to 15 years who presented mTBI and were at intermediate risk for clinically important traumatic brain injury (ciTBI). We compared the proportions of CT scans performed and of in-hospital observations before (2013–2014) and after (2014–2015) implementation of a modified PECARN rule including the S100B protein assay.ResultsWe included 1,062 children with mTBI (median age 4.5 years, sex ratio [F/M] 0.73) who were at intermediate risk for ciTBI: 494 (46.5%) during 2013–2014 and 568 (53.5%) during 2014–2015. During 2014–2015, S100B protein was measured in 451 (79.4%) children within 6 h after mTBI. The proportion of CT scans and in-hospital observations significantly decreased between the two periods, from 14.4 to 9.5% (p=0.02) and 73.9–40.5% (p<0.01), respectively. The number of CT scans performed to identify a single ciTBI was reduced by two-thirds, from 18 to 6 CT scans, between 2013–2014 and 2014–2015. All children with ciTBI were identified by the rules.ConclusionsThe implementation of a modified PECARN rule including the S100B protein assay significantly decreased the proportion of CT scans and in-hospital observations for children with mTBI who were at intermediate risk for ciTBI.

Download Full-text

Absolute protein assay for the simultaneous quantification of two epoxide hydrolases in rats by mass spectrometry‐based targeted proteomics

Journal of Separation Science ◽

10.1002/jssc.202100066 ◽

2021 ◽

Author(s):

Ting Wu ◽

Xiaoyun Xi ◽

Ying Chen ◽

Chao Jiang ◽

Qian Zhang ◽

...

Keyword(s):

Mass Spectrometry ◽

Targeted Proteomics ◽

Epoxide Hydrolases ◽

Protein Assay ◽

Simultaneous Quantification

Download Full-text

Prediction of Human Acute Toxicity by the Hep G2/24-hour/Total Protein Assay, with Protein Measurement by the CBQCA Method

Alternatives to Laboratory Animals ◽

10.1177/026119290503300304 ◽

2005 ◽

Vol 33 (3) ◽

pp. 207-213 ◽

Cited By ~ 4

Author(s):

Paul J. Dierickx

Keyword(s):

Protein Content ◽

Total Protein ◽

Total Protein Content ◽

Human Toxicity ◽

Hep G2 ◽

Vitro Assay ◽

Protein Assay ◽

Lowry Method ◽

Total Protein Assay

In our previously described Hep G2/24-hour/total protein assay, protein levels were measured by using the Lowry method. This assay was the best acute in vitro assay for the prediction of human toxicity within the Multicentre Evaluation of In Vitro Cytotoxicity (MEIC) study. In order to increase the MEIC data-base with a wider range of chemicals, we were interested in introducing the more practical 3-(4-carboxybenzoyl)-quinoline-2-carboxaldehyde (CBQCA) method for the quantification of the total protein content. Therefore, we investigated whether the same good results for the prediction of acute human toxicity would be obtained with the CBQCA method. The cells were treated for 24 hours, then cytotoxicity was determined by measuring the total protein content with CBQCA. The results were quantified by using the PI50c: the concentration (in mM) of test compound required to reduce the total protein content measured with the CBQCA-method by 50% as compared to the control cells. The results were compared with the PI50, the corresponding value when the Lowry method was used. A relatively low correlation was observed between PI50 and PI50c, reflecting the large and unexpected, differences when using the two protein assays. However, when comparing the log PI50c with the human toxicity, a correlation coefficient of r2 = 0.761 ( n = 44) was obtained for exactly the same series of MEIC chemicals. This value is clearly higher than that for the Lowry method ( r2 = 0.695). Compared to the Lowry method originally used, the Hep G2/24-hour/CBQCA total protein assay has the additional important advantage that it can be very easily adapted for large-scale analyses with robotic systems, including the on-line calculation of the results.

Download Full-text