The outbreak of the coronavirus disease (COVID-19) pandemic caused by the novel coronavirus (SARS-CoV-2) has been declared an international public health crisis. It is essential to develop diagnostic tests that can quickly identify infected individuals to limit the spread of the virus and assign treatment options. Herein, we report a proof-of-concept label-free electrochemical immunoassay for the rapid detection of SARS-CoV-2 virus via the spike surface protein. The assay consists of a graphene working electrode functionalized with anti-spike antibodies. The concept of the immunosensor is to detect the signal perturbation obtained from ferri/ferrocyanide measurements after binding of the antigen during 45 min of incubation with a sample. The absolute change in the [Fe(CN)6]3−/4− current upon increasing antigen concentrations on the immunosensor surface was used to determine the detection range of the spike protein. The sensor was able to detect a specific signal above 260 nM (20 µg/mL) of subunit 1 of recombinant spike protein. Additionally, it was able to detect SARS-CoV-2 at a concentration of 5.5 × 105 PFU/mL, which is within the physiologically relevant concentration range. The novel immunosensor has a significantly faster analysis time than the standard qPCR and is operated by a portable device which can enable on-site diagnosis of infection.

The measurement of microvessel density (MVD) is a widely accepted method for assessing the neoangiogenetic activity in neoplasia. The aim of the present study was to compare MVD with single nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor receptor (VEGFR)-1 and VEGFR-2 genes and, furthermore, with quantitative measurements of the receptors in colorectal cancer (CRC) tissue. Prognosis was also assessed. Blood and tissue were collected from 110 patients surgically resected for CRC. SNPs were analysed from genomic DNA by polymerase chain reaction. MVD was assessed by immunohistochemistry using CD34 and CD105 combined with caldesmon in order to identify also immature vessels. Microvessels were counted in three fields of vision, and the mean MVD was used for statistical analysis. The VEGFR-2 1192 C/T and -604 T/C SNPs were associated with the MVD assessed by CD105. The median MVD score for the 1192 CC genotype was significantly lower compared to the CT + TT genotypes (p = 0.002). The median MVD score for the -604 CC genotype was significantly higher compared to the TT + TC genotypes (p = 0.009). A possible association, although non-significant, was demonstrated for the CD34-positive microvessels. The 1192 CC genotype and the -604 TT + TC genotypes correlated with improved survival. This is the first report on correlations between SNPs in the VEGF receptor genes and MVD in patients with CRC. Associations were shown between two SNPs in the VEGFR-2 gene and the CD105-positive microvessels indicating an impact on neoangiogenesis. Moreover, an association between the SNPs and survival was demonstrated. The clinical implications of these findings need further investigations.

Extracellular superoxide dismutase (EC-SOD

Extracellular superoxide dismutase (EC-SOD) is a tetramer composed of either intact (Trpfor Gly enabled us to test these hypotheses. The mutation does not prevent proteolysis of the ECM-binding region but prevents a carboxypeptidase B-like enzyme from trimming residues beyond Gly 213 . The R213G mutation is located in the ECM-binding region, and individuals carrying this mutation have an increased concentration of EC-SOD in the circulatory system. In this study, we purified the R213G EC-SOD variant from heterozygous or homozygous individuals and determined the C-terminal residue of the processed subunit to be Gly 213 . This finding supports the two-step processing mechanism and indicates that the R213G mutation does not disturb the initial endoproteinase cleavage event but perturbs the subsequent trimming of the C terminus.